Abstract

The concentrations of nine metals (Cd, Pb, Ni, Cr, Co, Cu, Fe, Mn and Zn) were determined in lip sticks, lip glosses, lip balms, eye pencils, eyeliners, eye shadows, blushes, mascaras and face powders. The study was aimed at providing information on the risk associated with human exposure to metals in these facial cosmetic products. The concentrations of metals in the samples were measured by atomic absorption spectrometry after digestion with a mixture of nitric acid, hydrochloric acid and hydrogen peroxide. The mean concentrations of metals in these facial cosmetics ranged from 3.1 to 8.4 μg g−1 Cd, 12–240 μg g−1 Pb, 9.1–44 μg g−1 Cr, 18–288 μg g−1 Ni, 1.6–80 μg g−1 Cu, 7.9–17 μg g−1 Co, 2.3–28 mg g−1 Fe, 12–230 μg g−1 Mn, and from 18 to 320 μg g−1 Zn. The concentrations of Ni, Cr and Co were above the suggested safe limit of 1 μg g−1 for skin protection, while Cd and Pb were above the Canadian specified limits. The systemic exposure dosage (SED) values for these metals obtained from the use of these facial cosmetic products were below their respective provisional tolerable daily intake (PTDI)/or recommended daily intake (RDI) values. The margin of safety values obtained were greater than 100 which indicated that the concentrations of the metals investigated in these facial cosmetics do not present considerable risk to the users except in the case of face powders.

Abstract

The incidence of microstructural characteristics on the localization of plastic deformation in stretching plates in the form of necking was investigated by performing polycrystal plasticity simulations: crystal aggregates were generated by a Voronoї tessellation algorithm and crystal orientations were randomly distributed among the grains. The most outstanding results of this analysis, detailed in [1], are presented here. During dynamic extension, a transition is displayed between an initial grain scale strain organization towards the development of much larger patterns and a final stage during which one or a few localization zones develop drastically. The influence of the initial strain distribution on the final necking framework is enhanced when the number of grains in the plate thickness is reduced or the loading rate is moderate. Additionally, the sensitivity of the different stages of the localization process to texture has been highlighted: the co-existence of both favorably and unfavorably oriented grains raises the initial strain heterogeneity and triggers macroscopic localization at shorter times.

Abstract

Due to the accelerated growth of the population, the need for food has increased, this added to the differentiated climatic factors that Ecuador has, causes users to use pesticides and fertilizers in an alarming way, in search of increasing the productivity of crops, exploit an accumulation of residues in food and soil. In this study, the concentrations of metals and ions from fertilizers in four high-consumption products will be limited: INIAP Cecilia and Chaucha Amarilla potatoes, Kidney Tomato and Paiteña Onion found in markets and supermarkets. The metals were determined by inductively coupled plasma spectrometry with mass spectrometer (ICP-MS) and the ions through a UV-visible spectrophotometer. The values ​​found were within the norm. Differences were found between the metal content of the potato between peel and pulp where the latter will appear the highest concentrations. Multivariate statistics showed that the samples are grouped by the planting site and not the type of sample, which shows the importance of the soil and the cultivation process. The generation of a classification model for fed products with the analyzed parameters is discussed.

Abstract

Polychlorinated biphenyls (PCBs), industrial chemicals and persistent environmental pollutants, are found in rural and urban settings. Rodent studies have shown that exposure to PCB126, a dioxin-like PCB, causes a significant disruption of hepatic micronutrient homeostasis and an increase in metallothionein (MT), an antioxidant protein and metal carrier. A MT knockout mouse strain was used to assess metallothionein’s role in micronutrient disruption and overall hepatotoxicity. Twenty four 129S male mice (12 wild type (WT) and 12 MT knockout (MTKO)) were placed on a purified diet (AIN-93G) for 3 weeks to achieve hepatic metal equilibrium. Mice were then given a single IP injection of either vehicle or 150 μmol/kg PCB126 in vehicle. The animals were sacrificed 2 weeks later and organs processed for analysis. Liver histology, hepatic lipids, gene expression, micronutrient and ROS status were investigated. Liver weights, liver lipids, ROS, and hepatocyte vacuolation were increased with PCB126 exposure along with AhR responsive genes. The MTKO animals had more severe histological changes in the liver and elevated liver lipids than their wild type counterparts. Hepatic and renal metals levels (Cu, Zn, Se and Mn) were mostly reduced by PCB126 treatment. Renal micronutrients were more affected by PCB126 treatment in the MTKO animals. This research suggests that MT may not be the sole/primary cause of the metal disruption caused by PCB126 exposure in mice, but may provide protection against overall hepatotoxicity.