The influence of effective microorganisms (EM) and yeast on the degradation of strobilurins and carboxamides in leafy vegetables monitored by LC-MS/MS and health risk assessment.

The aim of this study was to determine the behaviour of strobilurin and carbocyamides commonly used in chemical protection of lettuce depending on carefully selected effective microorganisms (EM) and yeast (Y). Additionally, the assessment of the chronic health risk during a 2-week experiment was performed. The statistical method for correlation of physico-chemical parameters and time of degradation for pesticides was applied. In this study, the concentration of azoxystrobin, boscalid, pyraclostrobin and iprodione using liquid chromatography-mass spectrometry (LC-MS/MS) in the matrix of lettuce plants was performed, and there was no case of concentration above maximum residues levels. Before harvest, four fungicides and their mixture with EM (1 % and 10 %) and/or yeast 5 % were applied. In our work, the mixtures of 1%EM + Y and 10%EM + Y both stimulated and inhibited the degradation of the tested active substances. Adding 10%EM to the test substances strongly inhibited the degradation of iprodione, and its concentration decreased by 30 %, and in the case of other test substances, the degradation was approximately 60 %. Moreover, the addition of yeast stimulated the distribution of pyraclostrobin and boscalid in lettuce leaves. The risk assessment for the pesticides ranged from 0.4 to 64.8 % on day 1, but after 14 days, it ranged from 0.0 to 20.9 % for children and adults, respectively. It indicated no risk of adverse effects following exposure to individual pesticides and their mixtures with EM and yeast.

Experimental assessment of the effects of sublethal salinities on growth performance and stress in cultured tra catfish (Pangasianodon hypophthalmus).

The effects of a range of different sublethal salinities were assessed on physiological processes and growth performance in the freshwater 'tra' catfish (Pangasianodon hypophthalmus) juveniles over an 8-week experiment. Fish were distributed randomly among 6 salinity treatments [2, 6, 10, 14 and 18 g/L of salinity and a control (0 g/L)] with a subsequent 13-day period of acclimation. Low salinity conditions from 2 to 10 g/L provided optimal conditions with high survival and good growth performance, while 0 g/L and salinities >14 g/L gave poorer survival rates (p < 0.05). Salinity levels from freshwater to 10 g/L did not have any negative effects on fish weight gain, daily weight gain, or specific growth rate. Food conversion ratio, however, was lowest in the control treatment (p < 0.05) and highest at the maximum salinities tested (18 g/L treatment). Cortisol levels were elevated in the 14 and 18 g/L treatments after 6 h and reached a peak after 24-h exposure, and this also led to increases in plasma glucose concentration. After 14 days, surviving fish in all treatments appeared to have acclimated to their respective conditions with cortisol levels remaining under 5 ng/mL with glucose concentrations stable. Tra catfish do not appear to be efficient osmoregulators when salinity levels exceed 10 g/L, and at raised salinity levels, growth performance is compromised. In general, results of this study confirm that providing culture environments in the Mekong River Basin do not exceed 10 g/L salinity and that cultured tra catfish can continue to perform well.

Protein interactions with surfaces: Computational approaches and repellency.

Study of protein adsorption to solid surfaces continues to be substantial because of its role in cellular responses to biomaterials, interest in molecular aspects such as conformation and orientation, new methods for making protein repellent surfaces, and new application areas such as nanoparticles and microfluidics. This brief review is based only on very recent articles of particular interest to the authors, who each have worked in this area for some time. Simulations of protein interactions with surfaces and protein repellent surfaces are the only subtopics reviewed here.

Modeling the release of proteins from degrading crosslinked dextran microspheres using kinetic Monte Carlo simulations.

To optimize and predict the release of proteins from biodegradable microspheres based on crosslinked dextran, a fundamental understanding of the mechanisms controlling their release is necessary. For that purpose, a mathematical model has been developed to describe the release of proteins from these hydrogel-based microspheres. A kinetic Monte Carlo scheme for the degradation of a small domain inside the microsphere was developed. The results from this were used in a second kinetic Monte Carlo scheme to model the diffusion and the subsequent release of proteins. The only processes included in this model are diffusion and degradation. The general effects of diffusion, crosslink density, protein loading, and clustering of proteins on the release were investigated. The model crosslink density (Xmodel) and the model diffusivity (Dmodel) were fitted to experimental release data of BSA monomer from hydroxyethyl methacrylated dextran (dex-HEMA) microspheres. By using the experimental release curves of liposomes and BSA monomer, it was found that (1) the model crosslink density (Xmodel) scales with the hydrodynamic diameter (dh) as dh(1.64) and (2) the diffusivity of the protein (Dmodel) scales approximately with 1/dh (Stokes-Einstein). Using these scaling relations, quantitative predictions of the release curves of BSA dimer, immunoglobulin G and human growth hormone were possible. In conclusion, this model may play an important role in the optimization, understanding and prediction of the release of various proteins from degradable hydrogels.

Amended final report on the safety assessment of ethyl methacrylate.

Ethyl Methacrylate is a methacrylate ester used as a chemical additive in artificial fingernail enhancement products. These products may be applied by trained professionals or be provided directly to consumers with instructions for use. Ethyl Methacrylate readily polymerizes and rapidly reacts with multifunction methacrylates to form a highly cross-linked polymer. The oral LD(50) of Ethyl Methacrylate for rats ranged from 12.7 to 18.14 g/kg. In acute studies with rats, hemoglobinuria and respiratory tract lesions were observed. Animal studies indicate that Ethyl Methacrylate is a skin irritant and sensitizer. In some cases the results were dependent on the vehicle. Evidence of embryotoxicity and teratogenicity were observed in rats injected intraperitoneally with 0.1223 to 0.4076 ml/kg Ethyl Methacrylate. Positive evidence of mutagenicity was observed in the L5178Y mouse lymphoma cell assay, but not in two Ames tests. Case reports cite examples of individuals suffering allergic contact dermatitis from exposure to Ethyl Methacrylate and related methacrylates, and some degree of cross-reactivity appears to exist between widely used acrylates and methacrylates. Information from several clinical registries of sensitization reactions to various agents reported that Ethyl Methacrylate is a sensitizer, but not a potent one. Because Ethyl Methacrylate monomer is short-lived in the normal course of using artificial fingernail-enhancement products, the primary hazard is expected to be inadvertant skin contact. In order to avoid sensitization, it is necessary to avoid skin contact. It is recommended that fingernail-enhancement products containing Ethyl Methacrylate include directions to avoid skin contact because of the sensitizing potential. Based on the available data on the formulation of nail products containing this ingredient, it is concluded that Ethyl Methacrylate is safe as used, when application is accompanied by directions for use as above.

Assessment of structurally related chemicals: toxicity and ecotoxicity of acrylic acid and acrylic acid alkyl esters (acrylates), methacrylic acid and methacrylic acid alkyl esters (methacrylates).

BUA compiled the available data on toxicity and ecotoxicity for several acrylic and methacrylic acid esters and their corresponding acids. A comparison of these data revealed a qualitative similarity in the toxicological and ecotoxicological properties of the compounds considered. The data indicate that methacrylates are less reactive than the corresponding acrylates.