Scipedia: Documents published in 2017

Retrospective analysis of the experience with 100 cases of retroperitoneoscopy in Centro Hospitalar do Tâmega e Sousa

Scipedia content — Tue, 11 Apr 2017 11:28:44 +0200

Since the introduction of minimal invasive surgery in the 90s, many international urologic centres have developed retroperitoneoscopy as access way for treatment of multiple urologic pathologies. The aim of this work is to analyze our initial experience in retroperitoneoscopy. Materials and methods: Retrospective analysis of the first 100 cases of retroperitoneoscopy by counsulting the clinical records. These operations were classified according to their technical difficulty and operative risk. Operative complications were stratified into five grades using the modified Clavien classification system (CCS). The first 100 retroperitoneoscopic procedures of our hospital were performed from January 2008 to July 2013 in 51 men and 49 women with a mean age of 52 years old (18‐84 years old). They were comprised of 22 renal cyst marsupialization, 36 Simple Nephrectomies, 4 Radical Nephrectomies, 2 Nephroureterectomies, 14 dismembered pyeloplasties, 1 lumbar ureterolithotomy and 21 Parcial Nephrectomies. Using the classification of surgical complexity European Scoring System for Laparoscopic Operations in Urology modified by Rassweiler in 2006, we classified 22 procedures as simple, 57 procedures as difficult and 21 procedures as very difficult. The mean operation time was 158 minutes (range: 67‐280 minutes). The mean operation time was 96, 157, and 220 minutes in simple, difficult and very difficult procedures, repectively. The open conversion rate was 3%. A total of 12 patients had postoperative complications: CCS Grade I in 4, CCS Grade II in 6 and CCS Grade IIIb in 2 patients. Discussion/Conclusions: The retroperitoneoscopy has proven to be a safe and a versatile access for a minimally invasive treatment of many urologic pathologies.

Metilação do gene MST1R como biomarcador de diagnóstico em tumores de células renais

Scipedia content — Tue, 11 Apr 2017 11:28:38 +0200

Renal cell tumors comprise both benign – oncocytoma – and malignant – clear cell renal cell carcinoma, papillary renal cell carcinoma, and chromophobe renal cell carcinoma – entities. Since the differential diagnosis among renal cell tumors is sometimes difficult on clinical, imaging and pathological grounds, and prognosis is quite dissimilar, epigenetic-based diagnostic biomarkers, specially promoter methylation, might be useful for accurate diagnosis and therapeutic planning. EpiTect Methyl II PCR Array was used to screen methylation status of 22 genes, involved in epithelial to mesenchymal transition. Quantitative real-time methylation specific polymerase chain reaction was performed for candidate gene validation, and methylation levels of renal cell tumors subtypes and normal kidney were determined and compared. MST1R promoter methylation level was significantly higher in clear cell renal cell carcinoma (median: 5367) compared to other renal cell tumors (median: papillary renal cell carcinoma – 1084, chromophobe renal cell carcinoma – 1023, oncocytoma – 1337) and normal kidney (median: 1125), allowing for accurate discrimination from other renal cell tumors with high sensitivity (>96.7%) and specificity (86.7%). Quantitative MST1R promoter methylation may be useful as biomarker for accurate diagnosis of clear cell renal cell carcinoma in problematic cases.

Penile prosthesis in treatment of erectile dysfunction: 13‐year experience

Scipedia content — Tue, 11 Apr 2017 11:28:32 +0200

Penile prosthesis implantation is a common, well‐established treatment for correcting medical refractory erectile dysfunction. Although more invasive than some of the other currently available therapies, PP surgery has the advantages of high patient satisfaction rates. The aim of this study was to evaluate the surgical results and patient satisfaction after implantation of PP in 25 patients treated at the University Hospital of Coimbra (CHUC). We evaluated 25 patients with erectile dysfunction who underwent implantation of PP, inflatable and semi‐rigid, between November 2000 and November 2013. The information was obtained from medical records and telephone interviews and encompassed clinical severity, comorbidity, etiology, PP type, surgical complications, need for reintervention and degree of patient satisfaction. 88% of patients had severe ED. The main etiologies reported were: multifactorial (46.4%), atherogenic (24%) and neurologic (16%). Most devices implanted were inflatable prostheses (84%). In 80% of the cases there were no complications reported, the rate of re‐intervention was 20%. There were a high percentage of satisfied / very satisfied patients (65%). PP surgery remains an excellent alternative in restoring erectile function in patients whose medical therapies have failed. Despite its invasive nature, the implementation of PP has proven to be associated with a low rate of complications and a high degree of patient satisfaction.

Paratesticular adenomatoid tumor: a case report

Scipedia content — Tue, 11 Apr 2017 11:28:22 +0200

The adenomatoid tumor is a rare benign neoplasm of mesothelial origin, possible to occur in the genital tract in both sexes. It is commonly paratesticular, mainly in the epididymis. Surgical treatment consists of tumor resection and preservation of the testis whenever possible. We describe a case of a 40 years old man presenting scrotal discomfort, palpable lower pole mass of the right testicle and normal tumor markers. The patient underwent local excision of nodule with right testis preservation, as the neoplasm was unrelated with the albuginea. Subsequent pathology study (with histology and immunohistochemical markers) diagnosed a paratesticular adenomatoid tumor.

Intravesical bacilo de Calmette-Guérin therapy for bladder tumors / what we know so far

Scipedia content — Tue, 11 Apr 2017 11:28:17 +0200

The use of intravesical Bacillus Calmette-Guérin is a valid option in the treatment of non-muscle invasive bladder tumors, making it the main subject of a lot of publications. The aim of the present study is to review and consolidate the data available about this subject. A review of the data available was made on PubMed with the keywords: “intravesical BCG” and “non-muscle invasive bladder cancer”. Original and review articles written in English or Portuguese were selected. We present the discussion alongside the results for structural purposes. Scientific evidence strongly advises in favor of BCG use on intermediate and high risk tumors, due to its impact on the recurrence and possibly on the progression rates. It is important to be watchful for possible local and systemic side effects, that when detected call for a rightful therapeutically decision alongside the recommended schemes. The use of intravesical BCG with therapeutically purposes has strong evidence on the non-muscle invasive bladder tumors. More studies are needed in order to better understand the best administration scheme and its mechanism of action.

Effectiveness of penile vibratory stimulation after spinal cord injury

Scipedia content — Tue, 11 Apr 2017 11:28:12 +0200

Spinal cord injury in males is frequently associated with infertility, due to ejaculatory dysfunction and/or semen properties alterations. Penile vibratory stimulation can be used as a semen collecting method. The aim of this work is to disclose the use of this method in spinal cord injured male patients, evaluate its possible complications and clarify if the ejaculated semen is prone to fertilization. Vibratory stimulation was used in three spinal cord injured patients to collect semen and, after that procedure, the evaluation of sperm parameters was performed. Vibratory stimulation was efficient in all the subjects, in the majority of the sessions. The ejaculates present normal sperm concentration, but variable sperm progressive motility and morphology, when comparing with the standard criteria. Penile vibratory stimulation is an efficient procedure to induce ejaculation in spinal cord injured patients. Despite the considerable variability between the subjects, the ejaculates met the required quality to allow fertilization trough assisted reproductive technologies.

Complications of androgen deprivation therapy in prostate cancer / a review

Scipedia content — Tue, 11 Apr 2017 11:28:08 +0200

Androgen deprivation therapy (ADT) is the standard therapy for advanced prostate cancer. However, it encompasses several adverse effects, with impact on patient’s quality of life and, eventually, on overall survival. This article will review the most important side-effects associated with androgen deprivation therapy and the methods for minimizing their impact.

Sparing surgery for testicular tumors

Scipedia content — Tue, 11 Apr 2017 11:28:03 +0200

Malignant germ cell tumors represent the majority of testicular masses, according to current knowledge, radical orchiectomy remains the standard of care in the management of this type of cancer. However, testis‐sparing surgery (TSS) can be an alternative to radical surgery in selected cases, particularly in patients with small testicular masses (STM). The authors conducted a review of the current indications for performing testicular sparing surgery as well as functional and oncological results of it. We conducted a literature search in Medline database (PubMed) using the keywords: “testis sparing surgery”, “partial orchiectomy”, ‘testis tumor’, ‘small testicular mass/tumor’. The search was limited to article in English language, published from 2010 to the current date. randomized controlled trials/studies with high level of evidence that compare TSS with radical orchiectomy were not found. Indications for TSS are still controversial, particularly in patients with normal contralateral testis. The organ sparing surgery seems a viable therapeutic option for patients with small non‐palpable testicular mass (with

Use of acetylsalicylic acid, metformin and statins and prostate cancer: Impact on the pathological characteristics and risk of biochemical recurrence

Scipedia content — Tue, 11 Apr 2017 11:27:49 +0200

The impact of using ASA (acetylsalicylic acid), metformin and statins on the prostate cancer may be significant, but is not clear and findings from previous studies are inconsistent. This study aims to evaluate the relationship between the use of ASA, metformin and statins and the pathological characteristics and risk of biochemical recurrence (BCR) of prostate cancer. A total of 311 patients submitted to radical prostatectomy (RP) at Hospital de Braga between January 2010 and June 2014 were analyzed. Data were obtained from clinical records and the crude and adjusted association between the use of a specific drug and prostate specific antigen (PSA), pathological stage, Gleason score, positive surgical margin and risk of biochemical recurrence were calculated. Overall, 26 (8.4%) of the patients used ASA, 35 (11.3%) metformin and 112 (36%) statins. The ASA users had a lower PSA compared with the non users (5.9 vs. 8.9 ng/m, p = 0.008). Its use was an independent predictor of positive surgical margin (OR = 3.77, IC 95%: 1.45‐9.78). The use of metformin was associated with advanced pathological stages, more precisely pT3b (20% vs. 7.7%, p = 0.048). No other differences were detected between ASA, metformin and statins users. The use of ASA, metformin and statins has no beneficial effect on prostatic cancer patients. On the opposite, an association between the use of metformin and advanced pathological stages was observed. These results should be validated in other larger samples and longer follow‐up. The association between the use of ASA and lower PSA was already detected in other studies, whose mechanism should be clarified in future

Hyperbaric oxygen therapy for radiation‐induced hemorrhagic cystitis

Scipedia content — Tue, 11 Apr 2017 11:27:45 +0200

Due to considerable morbidity and mortality rates, radiation‐induced hemorrhagic cystitis is an important complication of pelvic irradiation. The available conservative treatment techniques show limited results. Hyperbaric oxygen has shown to be effective in the treatment of radiation‐induced lesions, including radiation cystitis. Our aim was to analyze the effectiveness and safety of hyperbaric oxygen therapy for refractory radiation‐induced hemorrhagic cystitis. Clinical records of 176 patients with refractory radiation‐induced hemorrhagic cystitis treated at our centre were retrospectively analyzed. The evolution of macroscopic hematuria was the main therapeutic outcome analyzed. 23, 9% of patients showed other radiation‐induced soft tissue lesions. After an average of 37 sessions of hyperbaric oxygen, 89, 8% of patients showed resolution of hematuria. Adverse events were reported in 1, 7% of patients. Hyperbaric oxygen was a safe and effective therapy for radiation‐induced hemorrhagic cystitis. Concomitant radiation‐induced soft tissue lesions were relatively frequent, which makes hyperbaric oxygen an excellent choice as first line treatment in those patients.

Considerations in the treatment of Peyronie disease

Scipedia content — Tue, 11 Apr 2017 11:27:41 +0200

Augmentation Cystoplasty using modified Studers Orthotopic Ileal Neobladder tecnhique

Scipedia content — Tue, 11 Apr 2017 11:27:37 +0200

Although exceedingly rare in developed countries nowadays, we still come across some devastating sequels of genitourinary tuberculosis, requiring careful medical evaluation and expertise on surgical reconstruction. A 58‐year‐old man, previously submitted to a right nephrectomy, developed a life‐threatening episode of urosepsis, leading to the need of a percutaneous nephrostomy due to a long stricture of the terminal ureter of the remaining left kidney. The patient had also developed very severe urinary frequency related to an extremely crippled bladder, with a capacity under 20 mL. After medical treatment of the tuberculosis, an augmentation cystoplasty was performed but in a patient‐tailored way, using an ileal neobladder constructed following the Studer technique that was anastomosed to the remaining bladder tissue with implantation of the healthy segment of the shortened ureter on the afferent limb of the reservoir. The normalisation of bladder capacity (over 250 mL), with preserved filling sensation allowed an excellent patient adaptation. The combination of a severely decreased bladder capacity with a stenosis of the terminal ureter of a single kidney led to a need of a great capacity reservoir as well as a reimplantation of a shortened ureter. The use of an orthotopic ileal neobladder as a large ileocystoplasty patch was the solution adopted.

Relação entre a qualidade seminal e o equilíbrio oxidativo nos espermatozoides

Scipedia content — Tue, 11 Apr 2017 11:27:32 +0200

Infertility is a clinical disorder affecting approximately 15% of reproductive-aged couples worldwide. Recently, the influence of oxidative stress (OS) in decreased semen quality has been discussed. OS corresponds to an imbalance between oxidants and antioxidants defenses, present in the organism. High levels of reactive oxygen species (ROS) damage biomolecules present in sperm cells and may lead to the loss of membrane integrity, DNA fragmentation or even to death by apoptosis. This study aimed to evaluate the correlation between human semen clinic parameters and parameters that assessed the presence of OS. A total of 32 semen samples, obtained from a randomized group of donors, were included in this study. Basic semen parameters were analyzed according to the WHOs guidelines. The total antioxidant capacity of sperm cells was measured as well as the expression of certain antioxidant proteins, namely superoxide dismutase (SOD) and glutathione peroxidase 4 (GPx4), by colorimetric techniques and immunoblotting, respectively. The effect of ROS in spermatozoa protein oxidation was analyzed by determining the presence of 3-nitrotyrosine and carbonyl groups, by slot blot. Lipid peroxidation was evaluated, by performing the thiobarbituric acid reactive substances (TBARS) assay with colorimetric tests. The results indicated that SOD was negatively correlated with viscosity (p = 0.035), volume (p = 0.004) and carbonyl groups presence (p = 0.005). This protein also showed a positive correlation with the presence of tail defects in sperm cells (p = 0.044). In turn, GPx4 showed a negative correlation with the presence of non-progressive motile spermatozoa (p = 0.012). TBARS assay revealed a negative correlation with the concentration of sperm cells (p = 0.000) and the total number of spermatozoa (p = 0.026), but, in turn, this assay showed a positive correlation with the volume of semen (p = 0.038). It was concluded that the seminal quality is affected by the oxidative balance in sperm cells. The obtained results suggest that lipid peroxidation leads to a reduction in sperm concentration, antioxidant proteins protect the spermatozoa against protein oxidation and contribute to an increased sperm motility and normal semen viscosity. Thus, evaluation of oxidative parameters may be a useful tool for male infertility diagnosis and follow-up of antioxidant treatments.

Microsurgical vasovasostomy: our experience

Scipedia content — Tue, 11 Apr 2017 11:27:27 +0200

To describe the initial experience of CHVNG/E in microsurgical vasovasostomy. The two‐layer technique was applied under microscope magnification in every patient by the same surgeon. 8 bilateral vasovasostomies were performed for vasectomy reversal between 2008 and 2014 at our unit. All the patients were available for follow‐up, with a mean follow‐up time of 6 months. Mean patient age was 38.8 ± 8.7 years and the interval between vasectomy and recanalization of 6 ± 1.5 years. Overall spermatozoid patency rate was 100%, with mobile spermatozoa in the ejaculate of all patients (median 12 x 106 /mL, interquartile interval [7 x 106 /mL‐21 x 106 /mL]). Four of the 8 patients fathered after the procedure. Our results were comparable to the ones described in the literature, confirming the performance of a good surgical technique. Microsurgical vasovasostomy constitutes a very safe method of vasectomy reversal, enabling couples to obtain pregnancies without additional medical treatment. To our knowledge, this is the first group of patients treated by this method in Portugal.

Ureteral reimplantation in urinary diversions: its the laparoscopy an option?

Scipedia content — Tue, 11 Apr 2017 11:27:22 +0200

The ureterointestinal stenosis is a relatively frequent complication after urinary diversions. The laparoscopic approach is rarely used but stay a therapeutic option. Show the surgical technique, step by step, of the laparoscopic ureteral/ureterointestinal estenosis correction. A vídeo of a distal ureteral stenosis laparoscopic correction, on a patient that undergone laparoscopic radical cystectomy with orthotopic neobladder confection, was presented. It was possible the laparoscopic correction of a distal right ureter estenosis with good results and no complications. The laparoscopic approach proved effective for treating ureter/ureterointestinal anastomosis stenosis and should be taken as a good option of treatment.

Nephrogenic adenoma of the urinary bladder: A case report and review of the literature

Scipedia content — Tue, 11 Apr 2017 11:27:15 +0200

Nephrogenic adenoma of the urinary bladder (NAB) is a rare and benign urothelial tumor. The existing literature is scarce regarding its etiology, clinical symptoms and therapeutic options. This paper presents the first reported case of a patient with HIV‐1 infection to whom an NAB was diagnosed. We report a case of a female patient of 49 years old, seropositive for HIV‐1, with pollakiuria, mictional urgency, feeling of incomplete bladder emptying and intermittent macroscopic hematuria. The patient was submitted to TURB of a suspected intravesical lesion. Histopathological examination of the resected material was consistent with an NAB. The patient is in follow‐up, having completed one year with no sign of lesion recurrence. NAB is a metaplastic lesion of the urothelial tissue. Its etiology is not fully understood. NAB is associated with chronic inflammatory processes or to a state of immunosuppression. Its diagnosis is histological, characterized by the presence of tubular structures similar to renal tubules. This work is particularly relevant because it is the first described case of NAB in a patient immunodepressed by HIV‐1 infection.

Mais um passo a caminho do objectivo - a excelência

Scipedia content — Tue, 11 Apr 2017 11:27:10 +0200

Efficacy of botulinum toxin type A in the treatment of neurogenic lower urinary tract disfunction due to spinal cord injury

Scipedia content — Tue, 11 Apr 2017 11:27:06 +0200

The prevalence of neurogenic lower urinary tract disfunction (NLUTD) is unknown, but the risk of developing NLUTD associated with spinal cord injury (SCI) is high. Verify the changes of intradetrusor BTX‐A injection on urodynamic parameters and in the QoL of NLUTD patients due to SCI. Retrospective study of 38 patients with SCI submitted to BTX‐A injection in our departments. Urodinamic studies were performed before and 3 to 6 months after treatment. QoL was evaluated by the Qualiveen questionnaire applied to 20 patients. Statistical analysis was performed with correlation tests for paired samples. Mean age was 38 years (Min = 23, Máx = 63), with 63.2% of males. The most frequent level of SCI was thoracic (52.6%). The average period between the SCI and the first treatment was 92 months (15 to 240 months). The patients had a mean of 3 treatments (min = 1, máx = 8), with 3 episodes of side effects ‐ transient and mild hypoasthenia. We collected data of urodynamic studies in 35 patients that showed increase in bladder capacity (p = 0, 24) and compliance (p

Cognitive Fusion targeted Prostate Biopsy after Multiparametric Magnetic Resonance Imaging. Comparison with traditional Randomized Biopsy

Scipedia content — Tue, 11 Apr 2017 11:26:57 +0200

Multiparametric Magnetic Resonance Imaging of the prostate (Mp‐MRI) allows the detection, localization and characterization of suspicious lesions for prostate cancer (PCa). When done prior to the diagnosis it also allows targeting of the biopsy, significantly improving the performance of the standard random prostate biopsy. Our goal is to compare a targeted biopsy technique (cognitive fusion) with the standard double sextant randomized prostate biopsy, and to determine which has better accuracy in the detection of cinically significant prostate cancer. 30 patients aged 61‐67 were selected with a PSA greater than 4 ng/mL (PSA between 5.6 – 19.2) and with suspicious PCa lesions on Mp‐MRI (Pi‐RADS 3‐5). A total of 75 suspicious lesions were detected. All biopsies were performed by the same Urologist (JMP), using trans‐rectal ultrasound guidance and after previous visualization of MRI images. Sampling was targeted to the area considered suspicious on MRI, using a Cognitive Fusion Technique, collecting two samples per area. After that, a double‐sextant standard prostate biopsy was also done in all patients. The variables used for statistical analysis were PCa detection rate and amount of cancer per sample. 22 patients were diagnosed with PCa. In 5 patients, cancer was only detected on targeted cores. Targeted biopsies diagnosed 17% more PCa when compared to random biopsies, and almost doubled the amount of cancer per sample. The overall PCa detection rate was 61% for all samples. 360 fragments were collected from standard randomized prostate biopsy, of which 169 were positive for PCa (47%), with a median Gleason score of 6 (3+3). The average amount of cancer per sample was 25% (5%‐85%). 105 of 150 fragments collected by cognitive fusion targeted biopsies were positive for PCa (70%). The median Gleason score was 7(3+4) with a median amount of cancer per sample of 45% (10%‐90%). Multiparametric prostatic MRI detects areas highly suspicious for PCa, allowing targeted biopsies, which increases diagnostic accuracy and improves the detection of clinically significant PCa.

A utilidade da quantificação do coeficiente aparente de difusão na estratificação de risco do cancro da próstata por ressonância magnética em 1,5 T sem sonda endorretal

Scipedia content — Tue, 11 Apr 2017 11:26:52 +0200

To evaluate the relationship between mean apparent diffusion coefficient (ADC) and post-surgical Gleason scores. To determine the diagnostic accuracy of multiparametric magnetic resonance imaging (mp-MRI) on a 1.5 T magnet in distinguishing low, intermediate and high-grade prostate tumors. This is a retrospective institutional-review-board-approved, single-center study including 30 patients (median age, 60 years) who underwent mp-MRI before prostatectomy for prostate cancer. Using histological reports for guidance, the tumors were localized in ADC maps, and mean ADCs were measured and examined for correlation with Gleason scores. 2 patients had 2 measurable foci, so a total of 32 tumors were studied. The diagnostic accuracy of the mean ADC was assessed by using the area under the receiver operating characteristic curve (ROC). In the differentiation of tumors with a Gleason score of 6 from those with a Gleason score of at least 7, mean ADC yielded an AUC of 0.76 (95% confidence interval: 0.59, 0.93). In the differentiation of tumors with Gleason scores of 6 or 7 from those with a Gleason score of at least 8, mean ADC yielded an AUC of 0.94 (95% confidence interval: 0.86, 1.00). Mean ADC values may allow a correct assessment of the patient risk using a 1.5 T magnet without ERC.

18F‐Fluorocholine PET/CT in prostate cancer initial staging

Scipedia content — Tue, 11 Apr 2017 11:26:46 +0200

In the evaluation of prostate cancer, clinical nomograms are commonly used to predict the probability of lymphatic and extra‐nodal spread. Those nomograms may suggest the presence and the extension of this cancer but do not allow a clear distinction between loco‐regional and distant disease. In this study, it was intended to evaluate the usefulness of 18F‐Fluorocoline positron emission tomography/computed tomography (18F‐FCH‐PET/CT) in the workup of patients with the initial diagnosis of prostate cancer and staged by this imaging technique. The medical records of 39 patients with prostate cancer who underwent 18F‐FCH PET/CT for initial staging, between November 2010 and April 2015, were reviewed. Of these, 20 patients were excluded because they had already started hormonotherapy. In the other 19 patients, the performance of 18F‐FCH PET/CT for the detection of lymph node metastasis was evaluated by calculating the sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy. Six patients had performed pelvic lymphadenectomy (total of 69 lymph nodes), allowing histological confirmation. When there was no histological confirmation (total of 30 lymph nodes and 3 cases of bone metastasis), the findings of 18F‐FCH PET/CT were correlated with the values of PSA and the information from multiple imaging modalities such as CT, bone scan, magnetic resonance (MRI), 18F‐Sodium Fluoride (18F‐NaF) PET/CT of control. The sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy for lymph node metastasis detection were, respectively, 96.8%, 80.9%, 69.8%, 98.2% and 85.8%. In our sample, this technique also allowed the identification of nodal extra pelvic or bone metastasis in 5 patients (26.3%) with implications in the treatment. It showed uptake suggestive of bone metastasis, corroborated by other diagnostic technics or by the follow‐up, in 3 patients, those with prostate specific antigen (PSA) of 9.5 ± 2.9 ng/mL. 18F‐FCH PET/CT is an entire body and multi organ imaging modality that allows the identification, globally, of the sites of disease in patients with prostate cancer. In this study, 18F‐FCH PET/CT showed good results when used in the initial staging of these patients. It is highlighted the ability to detect distant disease, in particular bone metastasis, even with PSA

Ureteropelvic junction obstruction caused by Fibroepithelial polyps in children

Scipedia content — Tue, 11 Apr 2017 11:26:41 +0200

Fibroepithelial polyps are extremely rare benign tumors arising from mesodermal tissue in the ureteral wall in children, that can cause ureteropelvic junction obstruction. In this report, we present an 11‐year‐old boy complaining of left intermitent lumbar pain related with ipsilateral hydronephrosis. Surgical exploration revealed several endoluminal polyps located at the ureteropelvic junction, obstructing the lumen of the ureter. Standard treatment consists in resection of the affected ureteral segment followed by open or laparoscopic dismembered pyeloplasty. The prognosis is excellent.

Adenocarcinoma do úraco – metástase atípica de um tumor raro

Scipedia content — Tue, 11 Apr 2017 11:26:30 +0200

We present the clinical case of a 74-year-old woman with an urachal tumor diagnosed in 2004. The patient underwent a partial cystectomy of the dome with remotion of the urachal remnant and the umbilicus. She had been clinical well until 2011 when she had a kidney metastasis from the urachal tumor. Urachal tumors are very rare, comprising 0.17-0.34% of all bladder cancers. The most common sites of distant metastases are: lung, lymph nodes, bone, intestine, brain, liver, peritoneum, skin and spine. We describe an extremely rare case of a renal metastasis from an urachal cancer, seven years after the initial diagnosis. Usually, patients with localized disease have a good prognosis when treated with surgery. The prognosis gets worse for patients with metastases or local recurrence because a standard chemotherapy regimen does not exist.

Renal oncocytoma – an incidentaloma

Scipedia content — Tue, 11 Apr 2017 11:26:25 +0200

Renal oncocytoma account for 3 to 7% of primary renal tumors. It is usually diagnosed incidentally and typically has a benign behavior. No currently used imaging techniques can reliably distinguish it from malignant lesions. Similarly, the microscopic diagnosis of oncocytoma remains a challenge. We present a case of an asymptomatic elderly, hypertensive, diabetic and with moderate chronic renal insufficiency, who underwent radical nephrectomy for a solid exophytic lesion of 4.7 cm in the renal pole, detected accidentally. Pathological examination revealed a renal oncocytoma. In this situation, partial nephrectomy would be the preferred surgical treatment, avoiding the long‐term risk of living with a single kidney. The lack of diagnostic tools that reliably differentiate between benign and malignant lesions makes this an important area of study, in order to reduce the number of surgical interventions and the associated morbidity.

Pollakiuria and imperforate hymen with hematocolpometra

Scipedia content — Tue, 11 Apr 2017 11:26:20 +0200

Introduction : Imperforate hymen occurs in approximately 1 in 1, 000 females. It can be found incidentally on physical examination, it is treatable and does not cause significant morbidity. If it is not screened for and treated early, patients present at menarche with a history of cyclical pelvic or abdominal pain and symptoms of urinary retention due to hematocolpos. Case presentation : A 12-year-old premenarchal girl presented to the emergency department with cyclical hypogastric abdominal pain and pollakiuria, with 6 months-evolution. Her medical history was unremarkable, she had never been menstruated or sexually active. She took no medications. Examination of the perineum revealed an imperforate hymen protruding from the introitus. A Y incision was made on the imperforate hymen and during hymenectomy 500mL of brown blood (viscous chocolate colored) was drained from the vagina. She was discharged on postoperative day 2. At the follow-up visit (52nd postoperative day), the patient reported her symptoms had resolved. Conclusion : Although rare, imperforate hymen with retrograde menstruation can cause dilatation of the vagina and uterus (i.e., hematocolpometra). It is an important differential diagnosis of abdominal pain in premenarchal girls often associated with urinary symptoms. It is easily diagnosed by physical examination. © 2014 Associação Portuguesa de Urologia. Published by Elsevier España, S.L.U. All rights reserved.

Mecanismos de infertilidade masculina na doença renal poliquística autossómica dominante

Scipedia content — Tue, 11 Apr 2017 11:26:15 +0200

Native tissue repairs in vaginal prolapse surgery – A 5‐year case series

Scipedia content — Tue, 11 Apr 2017 11:26:11 +0200

Currently, the use of mesh in surgery for pelvic organ prolapse has increased, mainly due to the high anatomic failure rate of native tissues repair. The objectives of this study were to analyze the results obtained in the surgical treatment of anterior and posterior defects with native tissues and assess the success rate. Retrospective study of 418 vaginal surgeries to repair defects in the anterior and posterior compartments using native tissues, performed in the Department of Urogynecology, from January 2008 to December 2012. In our sample, mean age was 64 years, with 90% of patients in menopause. 48.1% of women was hysterectomized, 78.2% were submitted to anterior colporrhaphy and 72.7% to posterior colporrhaphy. The correction of anterior paravaginal defect occurred in 32.5% of the surgeries and the posterior in 25.4%. Enterocele was repaired in 68.1% of cases. The intra‐operative and postoperative complications rate was 5%. Of the 347 patients evaluated in the postoperative period, 91.6% was discharged. Seven were later readmitted (2.2%). 29 women were kept in surveillance, mostly for recurrent prolapse, which worsened after a year of follow‐up. A total of 18 women was re‐operated, 13 for recurrence (3.7%). Therefore, the anatomic success rate was 80%. After adding the asymptomatic cases, in which anatomic cure was not achieve, the rate rose to 94%. The compartment defects correction rate of success, in our department, is in accordance with that described in the literature, with lower rates of complications and re‐interventions.

Urological outpatient surgery / Oporto’s hospital centre reality and assessment of grade of satisfaction

Scipedia content — Tue, 11 Apr 2017 11:26:02 +0200

The new Integrated Outpatient Surgery Centre (CICA) of Oporto’s Hospital Centre (CHP), opened in March/2011, developed around a paradigm of innovation and accurate protocols. Analysis of complications and Grade of satisfaction (Grade 1-5) of patients operated by Urology in the first 2 years of CICA, and their correlation through the χ2 test. 550 patients operated between March/2011 and April/2013, predominantly male (96.4%), mean age 43.5 years and anesthetic risk (ASA Average) 1.7. Main pathologies addressed: phimosis (34.0 %), hydrocele (22.7 %), varicocele (10.0%), and isolated short frenulum (6.9%). Mean surgical time 31.71 ± 14.32 min. Rate of early complications (

Adenocarcinoma incidental da próstata em doentes submetidos a cistoprostatectomia radical / um estudo retrospectivo

Scipedia content — Tue, 11 Apr 2017 11:25:57 +0200

Bladder cancer is responsible for 90-95% of urotelial carcinoma. Prostate Cancer is the most prevalent visceral tumor for males and one of the main oncological death causes. The presence of both tumours in the same individual is considered common. Radical cystoprostatectomy with lymphadenectomy and urinary diversion is the gold standard treatment for muscle-invasive bladder cancer. Incidental prostate cancer is described as being present in about 37.9% of cystoprostatectomy patients. To demonstrate the presence of incidental prostate cancer in cystoprostatectomy patients at our department. Clinical data concerning 72 men, from 2008 to 2013, at our institution were retrospectively reviewed. There was incidental prostate cancer in 19.4% of patients, being more frequent in patients older than 70 years of age. Lesions detected were small and circumscribed to the prostate. Four patients (5.6%) had clinically significant prostate cancer: one with a Gleason 7 (3 + 4), pT3b, one with a Gleason 7 (3 + 4), pT2c, one with a Gleason 7 (3 + 4), pT2a, and finally one with a Gleason 6 (3 + 3), with a positive surgical (urethral) margin. The most common histological pattern was Gleason 6 (3 + 3) (78.6%). pT2b predominated in 7 patients (9, 7%). There were equally 4.17% of patients with a pT2a and pT2c (3 patients each). Tumoral volume was inferior to 0.5 cc in 78.6% (11 patients) and superior/ equal to 0.5 cc in 22.4% (3 patients). There was only one patient with a biochemical relapse after 7 months of follow-up, initiating hormonal therapy at that time. Incidental prostate cancer rate was close to the one reported in the literature, being very variable, depending on the definition, the type of histopathological analysis, as the particular methodology of the study. Significative incidental prostate cancer was rare, requiring a closer follow-up with direct implications on the patient’s outcome. Standard pre-operatory evaluation is insufficient to determine precisely which tumours are eligible to this category. Adjuvant treatment for these tumours following cystoprostatectomy has been the same as if it were a prostate cancer following radical prostatectomy surgery. A common carcinogenesis pathway has been proposed and is currently being investigated. Prostate sparing cystectomy may occur in very selected individuals with a known oncological risk for disease progression with questionable functional benefits.

Training of Urology residents in laparoscopy - Comparison between Portugal and the rest of Europe

Scipedia content — Tue, 11 Apr 2017 11:25:52 +0200

''Objectives'' : To evaluate the exposure of Portuguese Urology residents (IP) to urological laparoscopy and to its training methods, comparing with the remaining Urology residents in Europe (IE).
''Materials and methods'' : A survey consisting of 23 questions concerning laparoscopic training, which was published online as well as distributed on paper, during the Annual European. Association of Urology Congress in 2012. Data was analysed with descriptive statistics, student t, Mann-Whitney and χ² tests.
''Results'' : We obtained 219 valid responses, 53 (24.2%) of which from IP. Conventional laparoscopy is equally available for both groups (78.8% of IP vs 72.0% of IE, p = NS). IP have greater access to single port laparoscopy (22.6% vs 8.4%, p

Uso de estatinas e níveis séricos do antigénio específico da próstata

Scipedia content — Tue, 11 Apr 2017 11:25:47 +0200

To quantify the effect of statins’ use on Prostate Specific Antigen (PSA) levels in patients referred to prostate biopsy and to determinate if the exposure to statins must be considered to improve the prostate cancer diagnostic accuracy of PSA. We selected 551 subjects with PSA

Laparoscopic resection of a retroperitoneal schwannoma: a case report and review of the literature

Scipedia content — Tue, 11 Apr 2017 11:25:41 +0200

Retroperitoneal schwannomas are rare, usually benign tumours that originate in the peripheral neural sheath. Preoperative diagnosis is often impossible. Few cases of laparoscopic removal of retroperitoneal schwannoma have been reported to date. We aim to report a case of retroperitoneal schwannoma using laparoscopic surgical technique. A 61‐year‐old man was found incidentally a solid retroperitoneal tumour by ultrasound. Abdominal computed tomography and magnetic ressonance imaging revealed a well‐defined, heterogeneous tumour, 3 cm in diameter, in pararrenal space close to psoas major. A transperitoneal laparoscopic resection was performed. Operative time was 65 minutes. The patient had an uneventful perioperative course. Histopathological exam revealed a benign schwannoma. No recurrence was detected after 2 years of follow‐up. Preoperative establishment of diagnosis is difficult in case of retroperitoneal schwannomas even with imagiologic or biopsy studies. Complete resection is the diagnosis and treatment of choice. Laparoscopic treatment is minimal invasive, safe and feasible for retroperitoneal schwannomas mainly because these lesions are well limited and hypovascular, allowing a careful dissection from adjacent structures through an improved visualization.

AMS 800 artificial urinary sphincter - retrospective analysis of six years

Scipedia content — Tue, 11 Apr 2017 11:25:29 +0200

Introduction : The artificial urinary sphincter (AUS) is the gold standard for surgical treatment of male stress urinary incontinence. Objective : Evaluate the results of the artificial urinary sphincter placement of AMS 800 in the Department of Urology of São João Hospital Center in a 6-year period (January 2007/December 2012). Material and methods : 30 male patients with urinary incontinence (UI) underwent placement of AUS AMS 800 through penoscrotal approach, with an average age of 69 years. 25 patients had severe incontinence and 5 moderate. With regard to etiology, UI secondary to radical prostatectomy (RP) in 26 patients, mixed incontinence (detrusor overactivity and PR) in 1 patient, prostatectomy for BPH in 1 patient, neurogenic UI in 2. 9 patients have a prior history of unsuccessful sling Invance, 14 a prior history of external pelvic radiotherapy and 8 a prior history of internal urethrotomy for stricture of vesico-urethral anastomosis. The mean postoperative follow-up was 22.1 months. Mean pads/day before surgery: 5.73. Results : 20 patients (67%) are fully continent (no protection), 5 patients (17%) partially improved or continents (1-2 pads per day or reduction of > 50% of the number of pads), 5 patients (17%) without improvement (≥ 3 pads/day). Adding cured and improved patients, we obtain an overall success rate of approximately 84%. The variation of pads/day before and after surgery (respectively 5.7 and 0.8) is statistically significant (p

Dynamic sentinel node biopsy in invasive squamous cell carcinoma of the penis: a single uro‐oncology Portuguese centre experience

Scipedia content — Tue, 11 Apr 2017 11:25:25 +0200

The 2014 European Association of Urology (EAU) guidelines on Penile cancer recommend dynamic sentinel node biopsy (DSNB) as a standard staging method for intermediate and high risk squamous cell carcinoma of the penis (SCCp), (≥ T1G2), c N0. The aim of this work is to evaluate the false negative rate and morbidity of our DSNB series. Since 2005 to 2014, 23 patients with SCCp and a patient with melanoma of the distal urethra, cN0, underwent DSNB in the urology department of Porto Portuguese Oncology Institute ‐ IPOPFG, EPE, Portugal. Bilateral inguinal ultrasound scan and fine needle aspiration cytology (FNAC) of suspicious inguinal nodes were not performed before DSNB. Lymphoscintigraphy starts in the morning of surgery with peri‐tumoral injection of albumin nanocoloid labeled with 99m Tc. Peri‐operatively, patent blue is injected into the dermis in peri‐tumoral location. The sentinel node is identified during surgery with the aid of lymphoscintigraphy images, a portable probe which detects gamma rays and identification of the blue dye in lymph nodes and vessels. The false negative rate was calculated per patient. The complication rate was calculated per groin within 30 days of DSNB. In 23 patients with SCCp, lymphoscintigraphy was bilateral in 7 patients. Biopsy was bilateral in 11 patients, with a mean number of lymph nodes excised per patient of 2, negative for metastasis in 20 patients. After median follow‐up of 45.5 months, we had a false negative. The false negative rate [1 false negative / (3 true positive + 1 false negative)] was 25%. The complication rate of BDGS per groin was 5.8%, with 2 minor linfoceles (Clavien I). Inguinal ultrasound and FNAC of suspicious lymph nodes before DSNB, although operator‐dependent, seems very important to decrease our false negative rate. The referral of patients with SCCp for DSNB can increase the number of patients undergoing this nodal staging method in Portugal. The DSNB morbidity is minimal.

Terapêuticas focais no tratamento do carcinoma da próstata localizado: o papel da eletroporação irreversível – presente ou futuro?

Scipedia content — Tue, 11 Apr 2017 11:25:21 +0200

In the PSA era, the incidence of localized prostate cancer has been increasing. This reality requires new therapeutic strategies, in order to give an answer to patients, in whom active surveillance may be indicate but desire more interventionist strategy with minimal side effects and without compromising cancer control. In these cases, focal therapies that include irreversible electroporation may be effective alternative strategies. The irreversible electroporation is an emergent approach on focal treatment of localized PCa. The nonthermal mechanism that preserves the tissue architecture without damaging tissue structures, such as vessels and nerves within the target region, is the main advantage comparatively to other techniques used in focal treatment. The number of clinical studies is reduced and the results still immature.

Treatment of cystine calculi - an observational retrospective review

Scipedia content — Tue, 11 Apr 2017 11:25:17 +0200

Introduction : Patients with cystinuria require multiple and varied treatments due to disease persistence and recurrence. In this study we analyzed therapeutic modalities and outcomes in the treatment of cystine calculi at a single academic center over the last 7 years. Materials and methods : We retrospectively analyzed patients undergoing invasive treatment of cystine calculi at our institution in the period between January 2006 and March 2013. Medical and surgical interventions and patient outcomes regarding stone-free status and renal function were considered. Results : A total of 7 cystinuric patients were invasively treated in our institution over the period of 7 years from January 2006 to March 2013. Of these 4 were male and 3 female with an average age at last follow-up of 39 years (range 19-59). Treatment modalities included medical therapy with high fluid intake, sodium restriction and urine alkalinization (all 7 patients), captopril (6 patients), and penicillamine (1 patient). These patients underwent a total of 156 procedures, with an average of 22.3 procedures per patient. All patients underwent extracorporeal shockwave lithotripsy (SWL), with a mean of 20 sessions per patient, range 8-35). Other treatment modalities included ureterorenoscopy and intracorporeal lithotripsy, (9 procedures in 4 patients, mean = 2, range 1-4), percutaneous nephrolithotomy (PCNL), (3 procedures in 3 patients), pyelolithotomy (2 procedures in 2 patients, one laparoscopic and one open) and one open nephrectomy (sepsis due to an atrophic kidney at presentation). Three patients have been stone free for the last 12 months, all have undergone PCNL or pyelolithotomy. Three patients have had serial renal scintigraphy, all maintained global and differential renal function over a period of 6 years (2 patients) and 2 years (1 patient) despite continued invasive procedures. Conclusions : In our series, more invasive procedures (PCNL or pyelolithotmy) were required for debulking disease burden or achieving a stone-free status. Medical therapy and repeated minimally invasive procedures, especially SWL, were required for preventing recurrence and treating residual stones. Despite the frequent use of procedures with potential deleterious effect for the kidney, in our series renal function was not affected either by the disease or its aggressive treatment over a period of several years. © 2014 Associação Portuguesa de Urologia. Published by Elsevier España, S.L.U. All rights reserved.

Erectile dysfunction and diabetes – evaluation of molecular alterations induced by oxidative stress

Scipedia content — Tue, 11 Apr 2017 11:25:12 +0200

Erectile dysfunction (ED) is one of the most common complications of diabetes, being oxidative stress an important feature of diabetic ED. Deleterious events induced by oxidative stress lead to crucial cellular and tissue alterations targeted by oxidative lesions. However, the noxious effects of oxidative stress mechanisms in penile tissue with the progression of diabetes, remains unclear. We intended to evaluate systemic and penile oxidative stress in an early and late stage of diabetes. Male Wistar rats were divided in groups: 2 and 8‐weeks of streptozotocin‐induced type 1 diabetes, and age‐matched controls. Systemic oxidative stress was evaluated in urine by hydrogen peroxide (H2 O2 ) quantification and in plasma by reduced/oxidized glutathione (GSH/GSSG) ratio. Penile oxidative status was assessed by H2 O2 production and by the evaluation of protein nitration through the detection of 3‐nitrotyrosine (3‐NT). 3‐NT was quantified by Western blotting analysis and immunohistochemistry allowed to identify its cavernosal cellular location. Systemic evaluation revealed a significant increase in urinary H2 O2 levels in both diabetic groups. A significant decrease of circulating GSH/GSSG ratio was observed in animals with late stage diabetes. In cavernosal tissue, H2 O2 production was significantly increased at 8‐weeks diabetes. Regarding 3‐NT cavernosal formation, data revealed a significant increment in advanced diabetes and a predominant location in cavernosal smooth muscle cells. We observed that systemic and cavernosal noxious effects induced by oxidative stress are predominant in advanced diabetes. Increased penile protein oxidative modifications in late‐staged diabetes may be responsible for structural/functional deregulations in cellular/molecular systems, contributing to the development of diabeticassociated ED.

Female urethral diverticula: A contemporary review

Scipedia content — Tue, 11 Apr 2017 11:25:07 +0200

Urethral diverticula affect from 0.6 to 4.7% of women, are a frequent cause of persistent urinary symptoms and can present with complications such as lithiasis and malignization. Today, underdiagnosis and diagnostic and therapeutic delay of female urethral diverticula are still common. The aim of this article is to analyse the state of art regarding ethiology, diagnosis and therapeutics of this disease. Bibliographic revision of articles published until January/2014 after search of the database Medline for the keywords: “female urethral diverticula”, “female urethral diverticulum”, “urethral diverticula”, “urethral diverticulum” and “female urethra”, and of bibliographic references of the articles obtained. Most female urethral diverticula are secondary to infection of the periurethral and urethral glands. Despite the classically described triad of dysuria, dyspareunia and post‐void dribbling, the clinical manifestations are diverse and unspecific. Over a third are palpable on gynaecologic examination. Imaging exams, namely magnetic resonance and ultrasound, have high diagnostic capability and contribute to surgical planning. Depending on location, conformation and associated symptoms, urethral diverticula can be managed conservatively or, more frequently, surgically. Clinical evaluation is still essential for the diagnosis of female urethral diverticula. Currently, magnetic resonance is considered to be the best modality to diagnose the diverticula and to exclude pre‐ and post‐operative complications. Less invasive techniques have been described but transvaginal urethral diverticulectomy yields the highest symptomatic cure rates. Awareness of the medical community is the most powerful weapon to reduce the underdiagnosis and diagnostic delay associated with female urethral diverticula.

Urolithiasis in the XXI century: bibliometric analysis of scientific publications in the last decade

Scipedia content — Tue, 11 Apr 2017 11:25:01 +0200

As the prevalence of urolithiasis is growing and there has been an increase in technologies and minimally invasive techniques in all areas of surgery, it would be expected that the total number of publications about this disease should increase. We hypothesized if there is also an evident trend towards the increase of urolithiasis related publications in urology journals. We evaluated the publications in five prestigious urology journals over the last decade, in order to perform a bibliometric analysis of every article published related to urinary lithiasis. An electronic search was performed using PubMed and all issues of British Journal of Urology International® (BJU Int), European Urology® (Eur Urol), Journal of Endourology® (J Endourol), Journal of Urology® (J Urol) and Urology® (Urology) were consulted from 2001 to 2010. All articles related to renal and ureteral lithiasis were collected, recorded and analyzed. A total of 30, 847 articles were published in these five prestigious journals. The J Urol was the journal with the most number of articles published per year with an average of 1146 papers. J Endourol was the publication with less publicated articles in this decade, with an average of 231 papers per year. There was a total of 1425 urolithiasis related papers in all journals. The J Endourol was the journal with the greatest number of urolithiasis related articles published in the period of analysis, with a total of 545 articles. The ratio of urolithiasis related articles and the total articles published per year in each journal was analyzed. The J Endourol was the publication with the greatest ratio. Eur Urol was the journal with less publications in urolithiasis, with ratios ranging from 0 in the year of 2010 and 5.3% in the year of 2003, with a decrease in the last years. All the other journals maintained a stable ratio of publications. Urolithiasis as a great subject to urologists practice would be expected to be an important source of original research studies in the more active urology journals. However, our study showed that, during the last decade, there was a steady number of urolithiasis related articles published in several journals.

Radical cystectomy / experience of an oncology center

Scipedia content — Tue, 11 Apr 2017 11:24:53 +0200

To present our clinical and surgical experience of radical cystectomy in bladder cancer, evaluate postoperative complications and overall survival. We performed a retrospective analysis of all patients undergoing radical cystectomy for bladder cancer between 2006 and 2010. Pathological characteristics were described based on 2009 TNM classification. We evaluated postoperative complications in the first 30 days after surgery according to the Clavien-Dindo classification and determined overall survival. We analyzed the data from 195 patients with a mean age of 67.8 years (28-87 years). 82.6% were male. The median follow-up was 2.5 years. Urothelial cancer was diagnosed in 93.8% cases. The majority of patients had extravesical disease with pathologic T3 stage in 28.7% and T4 in 22.1%. 32.8% of patients who underwent lymphadenectomy had positive lymph nodes. The most frequent urinary diversion was the ileal conduit, performed in 79% of cases, followed by neobladder in 10.3%. Postoperative complications were reported in 40.5% of patients, 28.2% were grade I/II and 12.3% were grade III-V, with a mortality rate of 3.6%. The overall survival at 3 years was 54% and at 5 years was 48%. The cases with disease localized to the bladder (≤ pT2N0) showed a 3-year survival of 89%. The presence of extravesical disease (≥ pT3) and lymph nodes metastasis confirmed to be poor prognostic factors, with a 3-year overall survival of 46% and 22%, respectively. This series results show that radical cystectomy is a complex surgery but with reasonable early postoperative morbidity and mortality. Surgery should be performed in the early stages of disease in order to offer the best survival outcomes.

Renal oncocytoma: Is URO‐CT useful in histological diagnosis?

Scipedia content — Tue, 11 Apr 2017 11:24:48 +0200

Over the past few years, the increasing use of cross‐sectional imaging, including ultrasound and computed tomography imaging, resulted in an increase incidental diagnosis of renal tumors, especially small renal masses (

Testis‐sparing surgery attempt: Case report

Scipedia content — Tue, 11 Apr 2017 11:24:37 +0200

Until the late 1980s, it was considered that any testicular mass, if suspicious, should be removed totally by radical orchiectomy, however, a marked increase in incidental testicular mass diagnosis, the high accuracy of diagnosis obtained from frozen section examinations, and evidence showing the potential advantages of testis‐sparing surgery, threw into question the need to sacrifice the entire testis even when a normal contralateral testis was present. We present a 23‐year‐old patient who was asymptomatic at diagnosis of a non‐palpable testicular mass with a size of approximately 7.5 mm and negative for tumor markers. He underwent a Testis‐sparing surgery guided by ultrasound with frozen section examination, however, with the suspicious of Germ cell tumor, it was decided to complete the orchiectomy. The final histological results were Leydig cell tumor. Given the high likelihood of non‐palpable and small testicular lesions being benign (80%), the negative impact of radical orchiectomy on spermatogenesis, cosmetic aspects, and endocrine function, impossible to ignore, Testis‐sparing surgery is a procedure that although it is not a standard procedure must be employed as the first approach in selected cases and specialized reference centers.

Características biológicas do carcinoma urotelial da bexiga: à descoberta de potenciais biomarcadores

Scipedia content — Tue, 11 Apr 2017 11:24:29 +0200

Urothelial bladder carcinoma (UBC), the most frequent type (90%) of bladder cancer and the second most common malignancy of the urogenital region, is a relatively well understood type of cancer, with numerous studies concerning pathogenetic pathways, natural history and bladder tumor biology being reported. Despite this, it continues to remain a challenge in the oncology field, mostly due to its relapsing and progressive nature, and to the heterogeneity in the response to cisplatin-containing regimens. Although the formulae based on clinical staging and histopathological parameters are classically used as diagnostic and prognostic tools, they have proven insufficient to characterize the individual biological features and clinical behaviour of the tumours. Understanding the pathobiology of the disease can add important information to these classical criteria, and contribute to accurately predict outcome and individualize therapy for UBC patients. In this line of investigation, we found that tumour angiogenesis and lymphangiogenesis, the process of invasion and metastasis and the energy metabolism reprogramming/tumour microenvironment encompass several potential biomarkers that seem to infl bladder cancer aggressiveness and chemoresistance. We particularly highlight the roles of lymphovascular invasion, and of RKIP, CD147 and MCT1 immunoexpressions, as relevant prognostic and/or predictive biomarkers, and as promising areas of therapeutic intervention, eliciting for the development of additional studies that can validate and further explore these biomarkers.

Prostatectomia radical laparoscópica versus aberta: margens cirúrgicas

Scipedia content — Tue, 11 Apr 2017 11:24:23 +0200

Laparoscopic radical prostatectomy has become an accepted alternative to open surgery. Our goal is to compare the oncological outcome of both approaches. The prospective study was initiated in September 2012, during 10 months. The high risk tumors were excluded from the study, only low and intermediate risk were included. We evaluated the following parameters: age, PSA, biopsy Gleason score, operative time, blood units, surgical margins, complications, Gleason score and TNM stage of the surgical specimen. Within 10 months, 45 patients underwent radical prostatectomy. 24 underwent laparoscopic approach and 21 the open approach. In the laparoscopic group, 70.8% (17) presented negative margins, 25% (6) positive margins and 4.17% (1) not suitable for classification. In the open approach 66.7% (14) presented negative margins, 28.6% (6) presented positive margins and 4.76% (1) not suitable for classification. It was used a Chi-Square Test considering positive and negative margins. No statistically differences were found (p value = 0.79). We evaluated the distribution of the different tumor stages T2a, T2b, T2c, T3a and T3b (TNM) in both groups. No difference was found in the distribution of the tumor stages in both groups. We have used a chi-square test (p value = 0.23). There is no association between the margins and the surgical approaches, and no association between the tumor stages and the two surgical approaches. We can conclude that the laparoscopic approach can be an alternative in low and intermediate risk cancers, even in low volume centres. © 2014 Associação Portuguesa de Urologia. Published by Elsevier España, S.L.U. All rights reserved.

Investigation on stacked cascade multilevel inverter by employing single-phase transformers

Scipedia content — Mon, 10 Apr 2017 16:21:45 +0200

In the present paper a new version of multilevel inverter is investigated. This new version is based on hybrid association of commutation cells with H-bridge cells. The association allows a significant reduction of the volume of the capacitors. In fact, presented topology allows us to work on higher input voltage levels with the same power switches. This new version is generally called as SCMI (stacked cascade multilevel inverter). The proposed inverter has potential to generate high quality waveforms, reduction in switching frequency, capable to operate at higher voltage levels and finally utilizes minimum number of switching components. The presented version of SCMI is simulated in Matlab-simulink and further, experimental validation is carried out in the laboratory with prototype setup.

Multi-response optimization of process parameters for TIG welding of Incoloy 800HT by Taguchi grey relational analysis

Scipedia content — Mon, 10 Apr 2017 16:21:32 +0200

Incoloy 800HT which was selected as one of the prominent material for fourth generation power plant can exhibit appreciable strength, good resistance to corrosion and oxidation in high temperature environment. This study focuses on the multi-objective optimization using grey relational analysis for Incoloy 800HT welded with tungsten inert arc welding process with N82 filler wire of diameter 1.2 mm. The welding input parameters play a vital role in determining desired weld quality. The experiments were conducted according to L9 orthogonal array. The input parameter chosen were the welding current, Voltage and welding speed. The output response for quality targets chosen were the ultimate tensile strength and yield strength (at room temperature, 750 °C) and impact toughness. Grey relational analysis was applied to optimize the input parameters simultaneously considering multiple output variables. The optimal parameters combination was determined as A2 B1 C2 i.e. welding current at 110 A, voltage at 10 V and welding speed at 1.5 mm/s. ANOVA method was used to assess the significance of factors on the overall quality of the weldment. The output of the mechanical properties for best and least grey relational grade was validated by the metallurgical characteristics:

Shadow removal using sparse representation over local dictionaries

Scipedia content — Mon, 10 Apr 2017 16:21:21 +0200

The presence of shadow in an image is a major problem associated with various visual processing applications such as object recognition, traffic surveillance and segmentation. In this paper, we introduce a method to remove the shadow from a real image using the morphological diversities of shadows and sparse representation. The proposed approach first generates an invariant image and further processing is applied to the invariant image. Here, shadow removal is formulated as a decomposition problem that uses separate local dictionaries for shadow and nonshadow parts, without using single global or fixed generic dictionary. These local dictionaries are constructed from the patches extracted from the residual of the image obtained after invariant image formation. Finally, non-iterative Morphological Component Analysis-based image decomposition using local dictionaries is performed to add the geometric component to the non-shadow part of the image so as to obtain shadow free version of the input image. The proposed approach of shadow removal works well for indoor and outdoor images, and the performance has been compared with previous methods and found to be better in terms of RMSE.

Design of optimal input–output scaling factors based fuzzy PSS using bat algorithm

Scipedia content — Mon, 10 Apr 2017 16:21:03 +0200

In this article, a fuzzy logic based power system stabilizer (FPSS) is designed by tuning its input–output scaling factors. Two input signals to FPSS are considered as change of speed and change in power, and the output signal is considered as a correcting voltage signal. The normalizing factors of these signals are considered as the optimization problem with minimization of integral of square error in single-machine and multi-machine power systems. These factors are optimally determined with bat algorithm (BA) and considered as scaling factors of FPSS. The performance of power system with such a designed BA based FPSS (BA-FPSS) is compared to that of response with FPSS, Harmony Search Algorithm based FPSS (HSA-FPSS) and Particle Swarm Optimization based FPSS (PSO-FPSS). The systems considered are single-machine connected to infinite-bus, two-area 4-machine 10-bus and IEEE New England 10-machine 39-bus power systems for evaluating the performance of BA-FPSS. The comparison is carried out in terms of the integral of time-weighted absolute error (ITAE), integral of absolute error (IAE) and integral of square error (ISE) of speed response for systems with FPSS, HSA-FPSS and BA-FPSS. The superior performance of systems with BA-FPSS is established considering eight plant conditions of each system, which represents the wide range of operating conditions.

Analysis of heatlines and entropy generation during double-diffusive MHD natural convection within a tilted sinusoidal corrugated porous enclosure

Scipedia content — Mon, 10 Apr 2017 16:20:46 +0200

The natural convection and entropy generation during double-diffusive MHD natural convection in a tilted sinusoidal corrugated porous enclosure is investigated numerically in this work by using heatline visualization technique. The top and bottom horizontal walls are assumed as adiabatic and non-diffusive, while the left and right vertical corrugated sidewalls are maintained at a constant hot and cold temperatures and concentrations respectively. The flow in the enclosure is subjected to an inclined magnetic field. The enclosure is filled with an electrically conducting fluid [Pr = 0.024] saturated with a porous media. The numerical computations are presented for various values of Rayleigh number (Ra), Hartmann number (Ha), Lewis number (Le), Darcy number (Da), buoyancy ratio (N), magnetic field orientation angle (φ) and enclosure inclination angle (Φ). In addition, the entropy generation due to fluid friction, thermal gradients, diffusion, and magnetic field beside the total entropy generation are studied and discussed. It is found that the flow circulation decreases strongly when the magnetic field applied horizontally and the enclosure is considered vertical. Heatline visualization concept is successfully applied to the considered problem. The average Nusselt number decreases when the Lewis number increases, while the average Sherwood number increases when the Lewis number increases. Also, both average Nusselt and Sherwood numbers increase when the Darcy number and buoyancy ratio increase. Moreover, the results show that the entropy generations due to magnetic field when the enclosure is subjected to the horizontal magnetic field are higher than the corresponding values when it subjected to the vertical magnetic field.

Magneto-dielectric properties of doped ferrite based nanosized ceramics over very high frequency range

Scipedia content — Mon, 10 Apr 2017 16:20:33 +0200

In the present study, indium doped nano sized nickel zinc cobalt based ferrite ceramics with composition Ni0.5 Zn0.3 Co0.2 Inx Fe2-x O4 (x = 0.2 and 0.4) were synthesized by a co-precipitation technique. Powdered sample has been pre-sintered at 800 °C, pressed into toroids and finally sintered at 1000 °C. The single phase formation of the presintered powder has been confirmed by X ray diffraction (XRD). The average particle size of the presintered powder has been estimated by field emission scanning electron microscope (FESEM) and found to be about ~60 nm for x = 0.2 and ~80 nm at x = 0.4. The electromagnetic characterization has been made using vector network analyzer. High value of permeability (17.3 and 15.2 for x = 0.2 and 0.4 respectively) with low magnetic loss tangent of 10−1 order were obtained. Permittivity of 8.2 and 10, and dielectric loss tangent of the order of 10−2 were also achieved. With the measured electromagnetic parameters, miniaturization factor of 12.32 and normalized characteristic impedance close to unity (1.23) were obtained up to 100 MHz frequency. These fascinating parameters definitely propose Ni0.5 Zn0.3 Co0.2 In0.4 Fe1.6 O4 ceramics as a substrate material for miniaturized antenna in very high frequency band. Possible reasons and mechanisms of electromagnetic properties for different concentrations of indium are discussed in the paper.

A novel transmission line protection using DOST and SVM

Scipedia content — Mon, 10 Apr 2017 16:20:19 +0200

This paper proposes a smart fault detection, classification and location (SFDCL) methodology for transmission systems with multi-generators using discrete orthogonal Stockwell transform (DOST). The methodology is based on synchronized current measurements from remote telemetry units (RTUs) installed at both ends of the transmission line. The energy coefficients extracted from the transient current signals due to occurrence of different types of faults using DOST are being utilized for real-time fault detection and classification. Support vector machine (SVM) has been deployed for locating the fault distance using the extracted coefficients. A comparative study is performed for establishing the superiority of SVM over other popular computational intelligence methods, such as adaptive neuro-fuzzy inference system (ANFIS) and artificial neural network (ANN), for more precise and reliable estimation of fault distance. The results corroborate the effectiveness of the suggested SFDCL algorithm for real-time transmission line fault detection, classification and localization.

Evaluation of in-cylinder mixture homogeneity in a diesel HCCI engine – A CFD analysis

Scipedia content — Mon, 10 Apr 2017 16:20:08 +0200

Performance and emission characteristics of HCCI engines depend on achieving a good in-cylinder homogeneous mixture. The formation of in-cylinder mixture depends on many engine parameters, which need optimization. In addition, as of now, there is no direct way to clearly describe and estimate in-cylinder mixture homogeneity. In the CFD analysis, it is evaluated indirectly using contour plots of equivalence ratio, variation of in-cylinder pressure with crank angles, heat release curves or by the comparison of emissions. In this study, an attempt has been made to develop methods to evaluate the in-cylinder mixture homogeneity by the CFD analysis using AVL-FIRE. Here, global and local in-cylinder fuel distribution and in-cylinder fuel distribution index are used to evaluate the mixture homogeneity. In order to evaluate these methods, mixture homogeneities in two cases of fuel injections with 7- and 10-hole injector are compared. Finally, we found that the global fuel distribution (GFD) plot helps direct quantitative assessment of mixture distribution in various ER range. However, the GFD method cannot explain the spatial variation of fuel distribution and does not provide mixture homogeneity on a simple scale. In the method of plotting fuel distribution index, the overall homogeneity will be evaluated on a scale of 0 to 1 by a simple way. In the method of plotting local fuel distribution (LFD), the spatial variation of mixture homogeneity is well defined in local zones both in radial and axial directions. Further, these proposed methods help us to reduce the computation time significantly.

Microcontroller USB interfacing with MATLAB GUI for low cost medical ultrasound scanners

Scipedia content — Mon, 10 Apr 2017 16:20:00 +0200

This paper presents an 8051 microcontroller-based control of ultrasound scanner prototype hardware from a host laptop MATLAB GUI. The hardware control of many instruments is carried out by microcontrollers. These microcontrollers are in turn controlled from a GUI residing in a computing machine that is connected over the USB interface. Conventionally such GUIs are developed using ‘C’ language or its variants. But MATLAB GUI is a better tool, when such GUI programs need to do huge image/video processing. However interfacing MATLAB with the microcontroller is a challenging task. Here, MATLAB interfacing through an intermediate MEX ‘C’ language program is presented. This paper outlines the MEX programming methods for achieving the smooth interfacing of microcontrollers with MATLAB GUI.

Effects of induced magnetic field and homogeneous–heterogeneous reactions on stagnation flow of a Casson fluid

Scipedia content — Mon, 10 Apr 2017 16:19:41 +0200

In this study, we analyzed the induced magnetic field effect on the stagnation-point flow of a non-Newtonian fluid over a stretching sheet with homogeneous–heterogeneous reactions and non-uniform heat source or sink. The transformed ordinary differential equations are solved numerically using Runge–Kutta and Newtons method. For physical relevance we analyzed the behavior of homogeneous and heterogeneous profiles individually in the presence of induced magnetic field. The effects of different non-dimensional governing parameters on velocity, induced magnetic field, temperature and concentration profiles, along with the skin friction coefficient and local Nusselt number, are discussed and presented through graphs. The results of the present study are validated by comparing with the existed literature. Results indicate that induced magnetic field parameter and stretching ratio parameter have the tendency to enhance the heat transfer rate.

Bat algorithm optimized fuzzy PD based speed controller for brushless direct current motor

Scipedia content — Mon, 10 Apr 2017 16:19:20 +0200

In this paper, design of fuzzy proportional derivative controller and fuzzy proportional derivative integral controller for speed control of brushless direct current drive has been presented. Optimization of the above controllers design is carried out using nature inspired optimization algorithms such as particle swarm, cuckoo search, and bat algorithms. Time domain specifications such as overshoot, undershoot, settling time, recovery time, and steady state error and performance indices such as root mean squared error, integral of absolute error, integral of time multiplied absolute error and integral of squared error are measured and compared for the above controllers under different operating conditions such as varying set speed and load disturbance conditions. The precise investigation through simulation is performed using simulink toolbox. From the simulation test results, it is evident that bat optimized fuzzy proportional derivative controller has superior performance than the other controllers considered. Experimental test results have also been taken and analyzed for the optimal controller identified through simulation.

Investigation on energy efficient sensor node placement in railway systems

Scipedia content — Mon, 10 Apr 2017 16:19:05 +0200

Recently wireless sensor network (WSN) has been widely used for monitoring railway tracks and rail tunnels. The key requirement in the design of such WSN is to minimize the energy consumption so as to maximize the network lifetime. This paper includes the performance of an improved medium access control (MAC) protocol, namely, time adaptive-bit map assisted (TA-BMA) protocol, for the purpose of communication between the sensors placed in a railway wagon. The train is considered to be moving at a constant speed, and the sensor nodes are stationary with respect to the motion of train. The effect of mobility on the proposed MAC protocol is determined using genetic algorithm (GA), and the observed increase in energy consumption on considering mobility is 18.51%. Performance analysis of the system model is carried out using QualNet (ver. 7.1), and the energy consumption in transmit mode, receive mode, percentage of time in sleep mode, end-to-end delay and throughput are investigated.

Free vibration analysis of pre-stressed FGM Timoshenko beams under large transverse deflection by a variational method

Scipedia content — Mon, 10 Apr 2017 16:18:42 +0200

A theoretical study on free vibration behavior of pre-stressed functionally graded material (FGM) beam is carried out. Power law variation of volume fraction along the thickness direction is considered. Geometric non-linearity is incorporated through von Kármán non-linear strain–displacement relationship. The governing equation for the static problem is obtained using minimum potential energy principle. The dynamic problem for the pre-stressed beam is formulated as an eigenvalue problem using Hamiltons principle. Three classical boundary conditions with immovable ends are considered for the present work, namely clamped–clamped, simply supported–simply supported and clamped–simply supported. Four different FGM beams, namely Stainless Steel–Silicon Nitride, Stainless Steel–Zirconia, Stainless Steel–Alumina and Titanium alloy–Zirconia, are considered for generation of results. Numerical results for non-dimensional frequency parameters of undeformed beam are presented. The results are presented in non-dimensional pressure-displacement plane for the static problem and in non-dimensional frequency-displacement plane for the dynamic problem. Comparative frequency-displacement plots are presented for different FGMs and also for different volume fraction indices.

Effect of welding parameters on pitting behavior of GTAW of DSS and super DSS weldments

Scipedia content — Mon, 10 Apr 2017 16:18:33 +0200

This work focuses on the effect of welding parameters on corrosion behavior of welded duplex stainless steel (DSS) and super duplex stainless steel (SDSS). The effect of welding parameters, such as heat input, inter-pass temperature, cooling rate, shielding/back purging gas, on corrosion behavior was studied. DSS and SDSS pipes were welded with Gas Tungsten Arc Welding (GTAW) process. After welding, the test samples were non-destructively tested to ensure no defects and test samples were prepared for microstructural examinations and ferrite content measurements. The root region had complex microstructure because of the repetitive heating of the zone during different weld layers. It was observed that at low heat input desirable microstructure was formed. The test samples were subjected to corrosion tests, i.e. ASTM G48 test for the determination of pitting corrosion rate, potentiodynamic polarization tests, and potentiostatic tests to verify susceptibility of the alloys to corrosion attack. DSS weldments had CPT in between 23 °C to 27 °C and SDSS weldments had CPT between 37 °C to 41 °C in potentiostatic measurements. The corrosion test results were correlated to the microstructures of the weldments. The pitting resistance of individual phases was studied and the effect of secondary austenite on corrosion attack was also observed.

Dry sliding wear behavior of epoxy fly ash composite with Taguchi optimization

Scipedia content — Mon, 10 Apr 2017 16:18:23 +0200

Epoxy resin matrix composite reinforced with fly ash particles was prepared by ultrasonic stirring method. Pin-on-disc wear test of the composite was carried out and compared according to Taguchi design-of-experiment. An orthogonal array exhibited and examined the influencing parameters like % of fly ash debris, typical load, sliding speed and track distance on the composite. Signal to noise ratio analysis optimizes the parametric condition that yields minimum wear rate, minimum frictional force and minimum coefficient of friction. A multi-criteria decision analysis method, TOPSIS is used to optimize the output, and confirmation test has been done to verify the projected model. ANOVA shows that applied normal load plays a vital role in increasing dry sliding wear of epoxy composites.

Influence of CaCO3 , Al2 O3 , and TiO2 microfillers on physico-mechanical properties of Luffa cylindrica /polyester composites

Scipedia content — Mon, 10 Apr 2017 16:18:15 +0200

The development of natural fibre reinforced polymer composites has gained popularity in many applications due to their environment friendly characteristics over the synthetic fibre based polymer composites. This paper describes the fabrication and physical, mechanical, three-body abrasive wear and water absorption behaviour of Luffa fibre reinforced polyester composites with and without addition of micro-fillers of Al2 O3, CaCO3 and TiO2 . The ranking of the composite materials has been made by using Technique for order preference by similarity to ideal solution (TOPSIS) method with output parameters of their physical, mechanical and abrasive wear and water absorption attributes. The addition of microfillers has enhanced greatly the physical and mechanical properties of Luffa -fibre based composites. The addition of microfillers has influenced the physico-mechanical properties of Luffa -fibre based polyester composites in descending order of CaCO3, Al2 O3, and TiO2 .

State of the art on tribological behavior of polymer matrix composites reinforced with natural fibers in the green materials world

Scipedia content — Mon, 10 Apr 2017 16:18:01 +0200

Natural fiber reinforced polymer composites have emerged as a potential environmentally friendly and cost-effective alternative to synthetic fiber reinforced composites. Therefore, in the past decade, a number of major industries, such as the automotive, construction and packaging industries, have shown a considerable interest in the progress of new natural fiber reinforced composite materials. The availability of natural fibers and the ease of manufacturing have tempted researchers to study their feasibility of their application as reinforcement and the extent to which they satisfy the required specifications in tribological applications. However, less information concerning the tribological performance of natural fiber reinforced composite material is available in the literature. Hence, the aim of this bibliographic review is to demonstrate the tribological behavior of natural fiber reinforced composites and find a knowledge about their usability for various applications that tribology plays a dominant role. This review presents the reported work on natural fiber reinforced composites with special reference to the type of fibers, matrix polymers, treatment of fibers and test parameters. The results show that composites reinforced with natural fibers have an improvement in tribological properties and their properties are comparable with conventional fibers. In addition, fiber treatment and fiber orientation are two important factors can affect tribological properties where treated fibers and normal oriented fibers exhibit better friction and wear behavior. This review is trying to evaluate the effect of test parameter including normal load and sliding speed on tribological properties, and the results vary based on type of reinforcement. Generally, due to their positive economic and environmental aspects, as well as their good tribological properties, natural composites are showing a good potential for employing in several applications.

Hydromagnetic flow over an unsteady curved stretching surface

Scipedia content — Mon, 10 Apr 2017 16:17:40 +0200

In this study, the boundary layer flow of an incompressible viscous fluid over an unsteady curved stretching surface is investigated in the presence of a variable applied magnetic field. Since the geometry is curved, the basic flow equations of the present problem are modeled using curvilinear coordinates. The obtained system is then reduced into nonlinear ordinary differential equations in two dependent quantities namely the fluid pressure and velocity by introducing suitable transformations. A numerical solution for fluid pressure and velocity is obtained by using a shooting method using Runge–Kutta integration scheme. The effects of various physical parameters on the fluid velocity and pressure distribution are shown through graphs and are discussed in detail. The comparison between the present and the existing results in the literature in special case for flat unsteady stretching, i.e. (K→∞K→∞ ), is found in good agreement.

Experimental investigation on mechanical and microstructural properties of AISI 304 to Cu joints by CO2 laser

Scipedia content — Mon, 10 Apr 2017 16:17:32 +0200

Aim of the present work is to investigate mechanical and metallurgical characteristics of continuous wave CO2 laser welded dissimilar couple of AISI 304 stainless steel and commercially pure copper sheets in autogenous mode. Metallurgical analysis of the fusion zone has been done to understand the mixing and solidification behavior. Macroscopic examination has been carried out to observe the macro-segregation pattern of Cu, Fe and Cr rich phases in different zones, and the thickness of HAZ was found to be around 10 µm. The micro-channels formed from the steel side to weld pool describe that the copper solidifies first and provides the nucleation surface for the residual melt to grow. These tubular micro-channels formed may be due to carbide precipitation. The EDS analysis conforms the well mixing of SS and Cu inside the weld pool. The mechanical properties in terms of tensile stress found up to 201 MPa and the fracture are obtained outside the weld zone. Microhardness measurements over the fusion zone have been done to understand the keyhole growth and quenching, solidification sequence and stress distribution over the full area.

Friction and wear behavior of nitrogen-doped ZnO thin films deposited via MOCVD under dry contact

Scipedia content — Mon, 10 Apr 2017 16:17:23 +0200

Most researches on doped ZnO thin films are tilted toward their applications in optoelectronics and semiconductor devices. Research on their tribological properties is still unfolding. In this work, nitrogen-doped ZnO thin films were deposited on 304 L stainless steel substrate from a combination of zinc acetate and ammonium acetate precursor by MOCVD technique. Compositional and structural studies of the films were done using Rutherford Backscattering Spectroscopy (RBS) and X-ray Diffraction (XRD). The frictional behavior of the thin film coatings was evaluated using a ball-on-flat configuration in reciprocating sliding under dry contact condition. After friction test, the flat and ball counter-face surfaces were examined to assess the wear dimension and failure mechanism. Both friction behavior and wear (in the ball counter-face) were observed to be dependent on the crystallinity and thickness of the thin film coatings.

Multi-objective optimized fuzzy-PID controllers for fourth order nonlinear systems

Scipedia content — Mon, 10 Apr 2017 16:16:56 +0200

In this paper, the Multi-objective Genetic Algorithm (MOGA) is used to obtain the Pareto frontiers of conflicting objective functions for the fuzzy-Proportional-Integral-Derivative (fuzzy-PID) controllers. The ball–beam and inverted pendulum fourth order nonlinear systems are regarded as nonlinear benchmarks. The considered objective functions for the ball–beam system are the distance error of the ball, the angle error of the beam, and the control effort. For the inverted pendulum system, the objective functions are the distance error of the cart, the angle error of the pendulum, and the control effort, which must be minimized simultaneously. The Pareto fronts are compared with those obtained by Multi-objective Particle Swarm Optimization (MOPSO). Four points are chosen from nondominated solutions of the obtained Pareto fronts based on the three conflicting objective functions and used for illustration of the state variables of the controlled systems. Obtained results elucidate the efficiency of the proposed controller in order to control nonlinear systems.

A hybrid press system: Motion design and inverse kinematics issues

Scipedia content — Mon, 10 Apr 2017 16:16:35 +0200

A hybrid machine (HM) is a system integrating two types of motor, servo and constant velocity with a mechanism. The purpose is to make use of the energy in the system efficiently with a flexible system having more than one degree of freedom (DOF). A review is included on hybrid press systems. This study is included as a part of an industrial project used for metal forming. The system given here includes a 7 link mechanism, one of link is driven by a constant velocity motor (CV) and the other is driven by a servo motor (SM). Kinematics analysis of the hybrid driven mechanism is presented here as inverse kinematics analysis. Motion design is very crucial step when using a hybrid machine. So motion design procedure is given with motion curve examples needed. Curve Fitting Toolbox (CFT) in Matlab® is offered as an auxiliary method which can be successfully applied. Motion characteristics are chosen by looking at requirements taken from metal forming industry. Results are then presented herein.

Design of microstrip-fed printed UWB diversity antenna with tee crossed shaped structure

Scipedia content — Mon, 10 Apr 2017 16:16:23 +0200

A compact, Ultra Wideband (UWB) antenna system for multi-input multi-output (MIMO)/diversity application is proposed. The antenna system is a microstrip structure with two similar triangular shaped radiating elements and a common ground plane. The radiating elements are excited by tapered feed for better impedance matching. A T-crossed shaped stub is added in the ground plane to increase the isolation between the two radiators. The overall dimension of the proposed antenna system is 46 mm × 32.6 mm × 1.6 mm. The measured impedance bandwidth (reflection coefficient

Analysis of low mutual coupling compact multi-band microstrip patch antenna and its array using defected ground structure

Scipedia content — Mon, 10 Apr 2017 16:16:10 +0200

In this paper, a simple microstrip patch antenna and a two-element E-plane coupled microstrip antenna array employing a defected ground structure are investigated. Without defected ground structure, the antenna has an impedance bandwidth of 675 MHz (6.78% at the center frequency of 9.955 GHz) and a gain of around 4.38 dB. The performance of the microstrip antenna in terms of impedance bandwidth, matching performance, gain and return loss can be improved by introducing a defect in the ground plane. As a result of which, bandwidth of 1.652 GHz (16.42% at the center frequency of 10.06 GHz) and a gain of 8.96 dB along with 5 different other operating bands are achieved. After integrating the microstrip antenna with the proposed defected ground structure, effective footprint of the antenna is reduced up to 66.95%. When integrated with proposed DGS array, the same antenna array structure shows miniaturization up to 78.97%. The proposed defected ground structure when compared to other techniques shows an exceptionally lower mutual coupling between two E-plane coupled microstrip antenna elements.

Exploration of waste cooking oil methyl esters (WCOME) as fuel in compression ignition engines: A critical review

Scipedia content — Mon, 10 Apr 2017 16:16:04 +0200

The ever growing human population and the corresponding economic development of mankind have caused a relentless surge in the energy demand of the world. The fast diminishing fossil fuel reserves and the overdependence of petroleum based fuels have already prompted the world to look for alternate sources of energy to offset the fuel crisis in the future. Waste Cooking Oil Methyl Ester (WCOME) has proven itself as a viable alternate fuel that can be used in Compression Ignition (CI) engines due to its low cost, non-toxicity, biodegradability and renewable nature. It also contributes a minimum amount of net greenhouse gases, such as CO2, SO2 and NO emissions to the atmosphere. The main objective of this paper is to focus on the study of the performance, combustion and emission parameters of CI engines using WCOME and to explore the possibility of utilizing WCOME blends with diesel extensively in place of diesel. The production methods used for transesterification play a vital role in the physiochemical properties of the methyl esters produced. Various production intensification technologies such as hydrodynamic cavitation and ultrasonic cavitation were employed to improve the yield of the methyl esters during transesterification. This review includes the study of WCOME from different origins in various types of diesel engines. Most of the studies comply with the decrease in carbon monoxide (CO) emissions and the increase in brake thermal efficiency while using WCOME in CI engines. Many researchers reported slight increase in the emissions of oxides of nitrogen. ANN modeling has been widely used to predict the process variables of the diesel engine while using WCOME. The versatility of ANN modeling was proven by the minimum error percentages of the actual and predicted values of the performance and emission characteristics.

Fast vector quantization using a Bat algorithm for image compression

Scipedia content — Mon, 10 Apr 2017 16:15:49 +0200

Linde–Buzo–Gray (LBG), a traditional method of vector quantization (VQ) generates a local optimal codebook which results in lower PSNR value. The performance of vector quantization (VQ) depends on the appropriate codebook, so researchers proposed optimization techniques for global codebook generation. Particle swarm optimization (PSO) and Firefly algorithm (FA) generate an efficient codebook, but undergoes instability in convergence when particle velocity is high and non-availability of brighter fireflies in the search space respectively. In this paper, we propose a new algorithm called BA-LBG which uses Bat Algorithm on initial solution of LBG. It produces an efficient codebook with less computational time and results very good PSNR due to its automatic zooming feature using adjustable pulse emission rate and loudness of bats. From the results, we observed that BA-LBG has high PSNR compared to LBG, PSO-LBG, Quantum PSO-LBG, HBMO-LBG and FA-LBG, and its average convergence speed is 1.841 times faster than HBMO-LBG and FA-LBG but no significance difference with PSO.

Impact of chemical reaction on Cu, Al2 O3 and SWCNTs–nanofluid flow under slip conditions

Scipedia content — Mon, 10 Apr 2017 16:15:26 +0200

Single walled carbon nanotube, alumina and copper nanoparticles on convective mass transfer in the presence of base fluid (water) over a horizontal plate are investigated numerically. The governing partial differential equations with auxiliary conditions are reduced into the system of coupled ordinary differential equations via similarity transformation and it has been solved numerically using fourth or fifth order Runge–Kutta–Fehlberg method with shooting technique. The results display that the diffusion boundary layer thickness of the water based Cu and SWCNTs is stronger than Al2 O3 –water with increase of chemical reaction.

Comparison of reliability techniques of parametric and non-parametric method

Scipedia content — Mon, 10 Apr 2017 16:15:16 +0200

Reliability of a product or system is the probability that the product performs adequately its intended function for the stated period of time under stated operating conditions. It is function of time. The most widely used nano ceramic capacitor C0G and X7R is used in this reliability study to generate the Time-to failure (TTF) data. The time to failure data are identified by Accelerated Life Test (ALT) and Highly Accelerated Life Testing (HALT). The test is conducted at high stress level to generate more failure rate within the short interval of time. The reliability method used to convert accelerated to actual condition is Parametric method and Non-Parametric method. In this paper, comparative study has been done for Parametric and Non-Parametric methods to identify the failure data. The Weibull distribution is identified for parametric method, Kaplan–Meier and Simple Actuarial Method are identified for non-parametric method. The time taken to identify the mean time to failure (MTTF) in accelerating condition is the same for parametric and non-parametric method with relative deviation.

Parametric simulation and experimental analysis of earth air heat exchanger with solar air heating duct

Scipedia content — Mon, 10 Apr 2017 16:15:08 +0200

Earth air heat exchanger (EAHE) systems are insufficient to meet the thermal comfort requirements in winter conditions. The low heating potential of such systems can be improved by integrating the system with solar air heating duct (SAHD). The aim of this paper is to present a model to estimate the heating potential for EAHE system with and without SAHD. The model is generated using TRNSYS 17 simulation tool and validated against experimental investigation on an experimental set-up in Ajmer, India. The experiment was done during the winter season, where the system was evaluated for different inlet flow velocities, length and depth of buried pipe. From the experimentation, it was observed that the depth of 3.7 m is sufficient for pipe burial and the 34 m length of pipe is sufficient to get optimum EAHE outlet temperature. It is also observed that increase in flow velocity results in drop in EAHE outlet temperature, while room temperature is found to increase for higher velocities (5 m/s). The COP of the system also increased up to 6.304 when assisted with solar air heating duct. The results obtained from the experiment data are in good agreement with simulated results within the variation of up to 7.9%.

An improved energy aware distributed unequal clustering protocol for heterogeneous wireless sensor networks

Scipedia content — Mon, 10 Apr 2017 16:14:58 +0200

In this paper, an improved version of the energy aware distributed unequal clustering protocol (EADUC) is projected. The EADUC protocol is commonly used for solving energy hole problem in multi-hop wireless sensor networks. In the EADUC, location of base station and residual energy are given importance as clustering parameters. Based on these parameters, different competition radii are assigned to nodes. Herein, a new approach has been proposed to improve the working of EADUC, by electing cluster heads considering number of nodes in the neighborhood in addition to the above two parameters. The inclusion of the neighborhood information for computation of the competition radii provides better balancing of energy in comparison with the existing approach. Furthermore, for the selection of next hop node, the relay metric is defined directly in terms of energy expense instead of only the distance information used in the EADUC and the data transmission phase has been extended in every round by performing the data collection number of times through use of major slots and mini-slots. The methodology used is of retaining the same clusters for a few rounds and is effective in reducing the clustering overhead. The performance of the proposed protocol has been evaluated under three different scenarios and compared with existing protocols through simulations. The results show that the proposed scheme outperforms the existing protocols in terms of network lifetime in all the scenarios.

Multiple-valued logic design based on the multiple-peak BiCMOS-NDR circuits

Scipedia content — Mon, 10 Apr 2017 16:14:50 +0200

Three different multiple-valued logic (MVL) designs using the multiple-peak negative-differential-resistance (NDR) circuits are investigated. The basic NDR element, which is made of several Si-based metal-oxide-semiconductor field-effect-transistor (MOS) and SiGe-based heterojunction-bipolar-transistor (HBT) devices, can be implemented by using a standard BiCMOS process. These MVL circuits are designed based on the triggering-pulse control, saw-tooth input signal, and peak-control methods, respectively. However, there are some transient states existing between the multiple stable levels for the first two methods. These states might affect the circuit function in practical application. As a result, our proposed peak-control method for the MVL design can be used to overcome these transient states.

Numerical study on flow separation in 90° pipe bend under high Reynolds number by k-ε modelling

Scipedia content — Mon, 10 Apr 2017 16:14:41 +0200

The present paper makes an effort to find the flow separation characteristics under high Reynolds number in pipe bends. Single phase turbulent flow through pipe bends is investigated using k-ε turbulence model. After the validation of present model against existing experimental results, a detailed study has been performed to study the influence of Reynolds number on flow separation and reattachment. The separation region and the velocity field of the primary and the secondary flows in different sections have been illustrated. Numerical results show that flow separation can be clearly visualized for bend with low curvature ratio. Distributions of the velocity vector show the secondary motion clearly induced by the movement of fluid from inner to outer wall of the bend leading to flow separation. This paper provides numerical results to understand the flow characteristics of fluid flow in 90° bend pipe.

Application of grey fuzzy logic for the optimization of CNC milling parameters for Al–4.5%Cu–TiC MMCs with multi-performance characteristics

Scipedia content — Mon, 10 Apr 2017 16:14:27 +0200

With the major application of MMCs, it is thus necessary to develop an appropriate technology for their efficient machining. Milling is the most common and versatile technology among different machining processes, characterized by an extensive range of metal cutting capacity that places it in a central role in the manufacturing industries. In the present study an attempt has been made to find out the most optimal level of process parameters for CNC milling of Al–4.5%Cu–TiC metal matrix composites using grey-fuzzy algorithm. Taguchis L25 orthogonal array design is used for performing CNC milling operation on the composite plates. The Grey fuzzy optimization of CNC milling parameters consist of three different output characteristics, such as, cutting force Fc, surface roughness Ra and surface roughness Rz. It was found that a cutting speed of 600 rpm, feed of 40 mm/min and a depth of cut of 0.30 mm is the optimal combination of CNC milling parameters that has produced a high value of grey fuzzy reasoning grade of 0.8191 which is close to the reference value. ANOVA analysis is carried out and it is found that among three different process parameters, the cutting speed played a major role on the determination of GFRG.

Test case minimization approach using fault detection and combinatorial optimization techniques for configuration-aware structural testing

Scipedia content — Mon, 10 Apr 2017 16:14:15 +0200

This paper presents a technique to minimize the number of test cases in configuration-aware structural testing. Combinatorial optimization is used first to generate an optimized test suite by sampling the input configuration. Second, for further optimization, the generated test suite is filtered based on an adaptive mechanism by using a mutation testing technique. The initialized test suite is optimized using cuckoo search (CS) along with combinatorial approach, and mutation testing is used to seed different faults to the software-under-test, as well as to filter the test cases based on the detected faults. To measure the effectiveness of the technique, an empirical study is conducted on a software system. The technique proves its effectiveness through the conducted case study. The paper also shows the application of combinatorial optimization and CS to the software testing.

Optimizing real power loss and voltage stability limit of a large transmission network using firefly algorithm

Scipedia content — Mon, 10 Apr 2017 16:13:59 +0200

This paper proposes a Firefly algorithm based technique to optimize the control variables for simultaneous optimization of real power loss and voltage stability limit of the transmission system. Mathematically, this issue can be formulated as nonlinear equality and inequality constrained optimization problem with an objective function integrating both real power loss and voltage stability limit. Transformers taps, unified power flow controller and its parameters have been included as control variables in the problem formulation. The effectiveness of the proposed algorithm has been tested on New England 39-bus system. Simulation results obtained with the proposed algorithm are compared with the real coded genetic algorithm for single objective of real power loss minimization and multi-objective of real power loss minimization and voltage stability limit maximization. Also, a classical optimization method known as interior point successive linear programming technique is considered here to compare the results of firefly algorithm for single objective of real power loss minimization. Simulation results confirm the potentiality of the proposed algorithm in solving optimization problems.

Analysis of enhancement in available power transfer capacity by STATCOM integrated SMES by numerical simulation studies

Scipedia content — Mon, 10 Apr 2017 16:13:50 +0200

Power system researches are mainly focused in enhancing the available power capacities of the existing transmission lines. But still, no prominent solutions have been made due to several factors that affect the transmission lines which include the length, aging of the cables and losses on generation, transmission and distribution etc. This paper exploited the integration of static synchronous compensator (STATCOM) and superconducting magnetic energy storage (SMES) which is then connected to existing power transmission line for enhancing the available power transfer capacity (ATC). STATCOM is power electronic voltage source converter (VSC) which is connected to the transmission system for shunt reactive power and harmonics compensation. SMES is a renowned clean energy storage technology. Feasibility of the proposed power system can control the real as well as reactive power flow independently between the transmission lines and STATCOM-(SMES) units. Complete proposed power system is implemented in numerical simulation software (Matlab/Simulink) and its performance is validated based on obtained investigation results.

Mechanical strength development of mortars containing volcanic scoria-based binders with different fineness

Scipedia content — Mon, 10 Apr 2017 16:13:39 +0200

The benefits of using natural pozzolan as cement replacement are often associated with shortcomings such as the need to moist-curing for longer time and a reduction of strength at early ages. The objective of the study is to investigate the influence of binder fineness on the mechanical strength development of scoria-based binder mortars. In the study, mortar specimens have been produced with four types of binder: one plain Portland cement (control) and three scoria-based binders with three replacement levels: 25%, 30% and 35%, respectively. All scoria-based binders have been inter-ground into four different Blaine fineness: 2400, 3200, 4200 and 5100 cm2 /g. The development of the compressive and flexural tensile strength of all mortar specimens with curing time has been investigated. The effects of the Blaine fineness of the scoria-based blended cement on the compressive and flexural strengths of mortar have been evaluated at curing ages of 2, 7, 28 and 90 days, respectively. Particle size distribution measured by a laser diffractometer has been considered in the study. Test results revealed that there is a decrease in strength with increasing amounts of scoria. In addition, there was found an increase in strength with increasing the Blaine fineness values. No direct relationship between Blaine and particle size distribution was observed. Effects of Blaine fineness on some physical properties of blended cements such as water demand, setting times and soundness have also been investigated. Further, an estimation equation for strength development incorporating the effects of fineness measured either by Blaine or by particle size distribution has been derived by the authors.

Comparison of different pressure waveforms for heat transfer performance of oscillating flow in a circular cylinder

Scipedia content — Mon, 10 Apr 2017 16:13:13 +0200

In the present investigation, an oscillating motion of unsteady Burgers fluid in a circular cylinder was modeled with different pressure waveforms. Three different waveforms are considered: the case of a trapezoidal, triangular and sinusoidal waveform. Analytical solutions of velocity and temperature distribution are obtained for an oscillating laminar flow, which can be used to analyze the effects of flow type on the heat transfer performance. The limiting cases have been considered to examine the heat transfer performance of four different non-Newtonian fluids. Results show that the heat transfer of the oscillating flow depends on the fluid material parameter, Prandtl number, amplitude oscillating waveform and radial coordinate. The trapezoidal and sinusoidal waveforms of oscillating motion can result in a higher heat transfer performance.

Flower pollination algorithm to solve combined economic and emission dispatch problems

Scipedia content — Mon, 10 Apr 2017 16:12:59 +0200

Economic Load Dispatch (ELD) is the process of allocating the required load between the available generation units such that the cost of operation is minimized. The ELD problem is formulated as a nonlinear constrained optimization problem with both equality and inequality constraints. The dual-objective Combined Economic Emission Dispatch (CEED) problem is considering the environmental impacts that accumulated from emission of gaseous pollutants of fossil-fuelled power plants. In this paper, an implementation of Flower Pollination Algorithm (FPA) to solve ELD and CEED problems in power systems is discussed. Results obtained by the proposed FPA are compared with other optimization algorithms for various power systems. The results introduced in this paper show that the proposed FPA outlasts other techniques even for large scale power system considering valve point effect in terms of total cost and computational time.

Facing Challenges Together

Scipedia content — Thu, 06 Apr 2017 15:23:43 +0200

The General Design and Technology Innovations of CAP1400

Scipedia content — Thu, 06 Apr 2017 15:23:37 +0200

The pressurized water reactor CAP1400 is one of the sixteen National Science and Technology Major Projects. Developed from Chinas nuclear R&D system and manufacturing capability, as well as AP1000 technology introduction and assimilation, CAP1400 is an advanced large passive nuclear power plant with independent intellectual property rights. By discussing the top design principle, main performance objectives, general parameters, safety design, and important improvements in safety, economy, and other advanced features, this paper reveals the technology innovation and competitiveness of CAP1400 as an internationally promising Gen-III PWR model. Moreover, the R&D of CAP1400 has greatly promoted Chinas domestic nuclear power industry from the Gen-II to the Gen-III level.

The Shandong Shidao Bay 200 MWe High-Temperature Gas-Cooled Reactor Pebble-Bed Module (HTR-PM) Demonstration Power Plant: An Engineering and Technological Innovation

Scipedia content — Thu, 06 Apr 2017 15:23:30 +0200

After the first concrete was poured on December 9, 2012 at the Shidao Bay site in Rongcheng, Shandong Province, China, the construction of the reactor building for the worlds first high-temperature gas-cooled reactor pebble-bed module (HTR-PM) demonstration power plant was completed in June, 2015. Installation of the main equipment then began, and the power plant is currently progressing well toward connecting to the grid at the end of 2017. The thermal power of a single HTR-PM reactor module is 250 MWth, the helium temperatures at the reactor core inlet/outlet are 250/750 °C, and a steam of 13.25 MPa/567 °C is produced at the steam generator outlet. Two HTR-PM reactor modules are connected to a steam turbine to form a 210 MWe nuclear power plant. Due to Chinas industrial capability, we were able to overcome great difficulties, manufacture first-of-a-kind equipment, and realize series major technological innovations. We have achieved successful results in many aspects, including planning and implementing R&D, establishing an industrial partnership, manufacturing equipment, fuel production, licensing, site preparation, and balancing safety and economics, these obtained experiences may also be referenced by the global nuclear community.

Health in an Aging World: What Should We Do?

Scipedia content — Thu, 06 Apr 2017 15:23:22 +0200

Sustainable Management of Water Resources

Scipedia content — Thu, 06 Apr 2017 15:23:17 +0200

Design and R&D Progress of China Lead-Based Reactor for ADS Research Facility

Scipedia content — Thu, 06 Apr 2017 15:23:10 +0200

In 2011, the Chinese Academy of Sciences launched an engineering project to develop an accelerator-driven subcritical system (ADS) for nuclear waste transmutation. The China Lead-based Reactor (CLEAR), proposed by the Institute of Nuclear Energy Safety Technology, was selected as the reference reactor for ADS development, as well as for the technology development of the Generation IV lead-cooled fast reactor. The conceptual design of CLEAR-I with 10 MW thermal power has been completed. KYLIN series lead-bismuth eutectic experimental loops have been constructed to investigate the technologies of the coolant, key components, structural materials, fuel assembly, operation, and control. In order to validate and test the key components and integrated operating technology of the lead-based reactor, the lead alloy-cooled non-nuclear reactor CLEAR-S, the lead-based zero-power nuclear reactor CLEAR-0, and the lead-based virtual reactor CLEAR-V are under realization.

The Progress and Grand Challenge of Urbanization in China

Scipedia content — Thu, 06 Apr 2017 15:23:03 +0200

HPR1000: Advanced Pressurized Water Reactor with Active and Passive Safety

Scipedia content — Thu, 06 Apr 2017 15:22:56 +0200

HPR1000 is an advanced nuclear power plant (NPP) with the significant feature of an active and passive safety design philosophy, developed by the China National Nuclear Corporation. On one hand, it is an evolutionary design based on proven technology of the existing pressurized water reactor NPP, on the other hand, it incorporates advanced design features including a 177-fuel-assembly core loaded with CF3 fuel assemblies, active and passive safety systems, comprehensive severe accident prevention and mitigation measures, enhanced protection against external events, and improved emergency response capability. Extensive verification experiments and tests have been performed for critical innovative improvements on passive systems, the reactor core, and the main equipment. The design of HPR1000 fulfills the international utility requirements for advanced light water reactors and the latest nuclear safety requirements, and addresses the safety issues relevant to the Fukushima accident. Along with its outstanding safety and economy, HPR1000 provides an excellent and practicable solution for both domestic and international nuclear power markets.

Responding to Global Changes as a Community of Common Destiny

Scipedia content — Thu, 06 Apr 2017 15:22:50 +0200

Fitting on the Earth: Challenges of Carbon and Nitrogen Cycle to Preserve the Habitability of the Planet

Scipedia content — Thu, 06 Apr 2017 15:22:46 +0200

Informatics: The Frontier of Innovation in Health and Healthcare

Scipedia content — Thu, 06 Apr 2017 15:22:42 +0200

Human-Centered Mobility: A New Approach to Designing and Improving Our Urban Transport Infrastructure

Scipedia content — Thu, 06 Apr 2017 15:22:36 +0200

In-Vessel Melt Retention of Pressurized Water Reactors: Historical Review and Future Research Needs

Scipedia content — Thu, 06 Apr 2017 15:22:29 +0200

A historical review of in-vessel melt retention (IVR) is given, which is a severe accident mitigation measure extensively applied in Generation III pressurized water reactors (PWRs). The idea of IVR actually originated from the back-fitting of the Generation II reactor Loviisa VVER-440 in order to cope with the core-melt risk. It was then employed in the new deigns such as Westinghouse AP1000, the Korean APR1400 as well as Chinese advanced PWR designs HPR1000 and CAP1400. The most influential phenomena on the IVR strategy are in-vessel core melt evolution, the heat fluxes imposed on the vessel by the molten core, and the external cooling of the reactor pressure vessel (RPV). For in-vessel melt evolution, past focus has only been placed on the melt pool convection in the lower plenum of the RPV, however, through our review and analysis, we believe that other in-vessel phenomena, including core degradation and relocation, debris formation, and coolability and melt pool formation, may all contribute to the final state of the melt pool and its thermal loads on the lower head. By looking into previous research on relevant topics, we aim to identify the missing pieces in the picture. Based on the state of the art, we conclude by proposing future research needs.

Climate Intervention: Possible Impacts on Global Security and Resilience

Scipedia content — Thu, 06 Apr 2017 15:22:24 +0200

Insecurity by Design: Todays IoT Device Security Problem

Scipedia content — Thu, 06 Apr 2017 15:22:20 +0200

A Triumph of Science−and Engineering

Scipedia content — Thu, 06 Apr 2017 15:22:16 +0200

Can Engineers Lead Again?

Scipedia content — Thu, 06 Apr 2017 15:22:12 +0200