Results for "diaphragm" : Scipedia

Is surgical plication necessary in diaphragm eventration?

Abstract

Diaphragm plication surgery is conducted to remove dyspnea, which results from mediastinal shift, atelectasia, and ventilation/perfusion dyssynchrony in lungs that occur because of an eventrated diaphragm. This study aims to determine whether diaphragm plication has any effect on respiration by analyzing the patients' changing values in the respiratory function test (RFT) after plication surgery. Sixteen patients who underwent diaphragm plication surgery in our clinic because of plication eventration or paralysis were examined prospectively. Diaphragm eventration values were assessed using a calculation method that uses posteroanterior pulmonary radiographies taken during patient admission and control, then, these data were recorded. The amount of changes in the eventration levels and in restrictive respiratory failure parameters—forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC) of RFTs—conducted in pre- and postoperative control periods were compared using statistical analysis methods. The compatibility between the amounts of RFT changes was examined through a satisfaction survey—using a questionnaire that consisted of multiple choice questions with answer options such as “better, ” “the same, ” and “worse”—to understand preoperative and postoperative symptom levels in the 12th month of postoperative control. According to postoperative levels, a decrease between 19% and 23% was observed in eventration amounts within the 1st postoperative month, 6th postoperative month, and 12th postoperative month. In addition, the highest average increase in FEV1 liter (lt) values was 0.2 lt and 0.25 in FVC (lt) values. Researchers of this study believe that more distinctive decisions need to be taken while identifying patients for surgery in unilateral diaphragm eventrations, especially in the adult patient group, surgical option should be used for cases in which the eventrated diaphragm results in mediastinal shift and respiratory failure.

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Collection of Toxicology Reports

Downregulation of nicotinic and muscarinic receptor function in rats after subchronic exposure to diazinon

Abstract

Diazinon (DZN) is an organophosphate insecticide which exerts its effect through the inhibition of acetylcholinesterase enzyme (AChE). In this work, we studied the development of tolerance to subchronic p.o. administration of DZN in rats, under both in vivo and in vitro conditions. [...]

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Revista Internacional de Métodos Numéricos para Cálculo y Diseño en Ingeniería

Coupled Thermal-Structural Analysis and Structural Optimization of the Diaphragm of a Diaphragm Compressor for a Hydrogen Refueling Station

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Diaphragm fatigue fracture stands as one of the primary failure modes in hydrogen refueling station diaphragm compressors, urgently requiring systematic investigation into the mechanical properties and fatigue reliability of diaphragms under actual service conditions. However, due to the complex contact state between the diaphragm and the gas cavity cover plate (gas passage, gas hole)/oil cavity support plate and oil distribution plate (oil passage, oil hole), it is difficult to accurately obtain the stress distribution state of the diaphragm. In this study, we conducted material property experiments on the diaphragm to characterize its constitutive parameters. A refined numerical simulation model of the cover platediaphragm-support plate was established to analyze the mechanical properties of the diaphragm group under different conditions. The influence of diaphragm thickness on stress distribution and fatigue life was also explored. The results indicated that high stress distribution areas were mainly concentrated in the cavity transition zone and in the overlapping area of the diaphragm and gas passage/oil passage. The temperature inside the diaphragm compressor cavity had a significant impact on the stress level of the diaphragm. When the cavity temperature reached 300°C, the maximum von Mises stress reached 1286 MPa. The optimization results of diaphragm thickness indicated that when the diaphragm thickness was within the range of [0.3, 0.5 mm], the diaphragm was at a low stress service level; considering both the fatigue life and deflection performance of the diaphragm, the diaphragm thickness should be selected as thick as possible within the range of [0.3, 0.5 mm]. The numerical simulation model of the diaphragm compressor and the structural optimization design method of the diaphragm proposed in this article have significant engineering implications for improving the fatigue life of diaphragm compressor diaphragms.OPEN ACCESS Received: 02/03/2025 Accepted: 13/05/2025 Published: 14/07/2025

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