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The SAM-Krom biomonitoring study shows occupational exposure to hexavalent chromium and increased genotoxicity in Denmark
Full text linkBackground
Hexavalent chromium (Cr(VI)) is a carcinogen. Exposure to Cr(VI) may occur in different industrial processes such as chrome plating and stainless steel welding. The aim of this study was to assess occupational exposure to Cr(VI) in Denmark.
Methods
This cross-sectional study included 28 workers and 8 apprentices with potential Cr(VI) exposure and 24 within company controls, all recruited from six companies and one vocational school. Use of occupational safety and health (OSH) risk prevention measures were assessed through triangulation of interviews, a questionnaire and systematic observations. Inhalable Cr(VI) and Cr-total were assessed by personal air exposure measurements on Cr(VI) exposed participants and stationary measurements. Cr concentrations were measured in urine and in red blood cells (RBC) (the latter reflecting Cr(VI)). Genotoxicity was assessed by measurement of micronuclei in peripheral blood reticulocytes (MNRET).
Results
At announced visits, a consistent high degree of compliance to OSH risk prevention measures were seen in ‘chromium bath plating’ for both technical devices (e.g. ventilation, plastic balls, sheet coverings) and in the use of personal protective equipment (e.g. gloves, respirators), yet a lesser degree of compliance was observed in ‘stainless steel welding’. The geometric mean of the air concentration of Cr(VI) was 0.26 μg/m3 (95% confidence interval (CI): 0.12–0.57) for the Cr(VI)-exposed workers and 3.69 μg/m3 (95% CI: 1.47–9.25) for the Cr(VI)-exposed apprentices. Subdivided by company type, the exposure levels were 0.13 μg/m3 (95% CI: 0.04–0.41) for companies manufacturing and processing metal products, and 0.81 μg/m3 (95% CI: 0.46–1.40) for bath plating companies. Workers with occupational exposure to Cr(VI) had significantly higher median levels of urinary Cr (2.42 μg/L, 5th-95th percentile 0.28–58.39), Cr in RBC (0.89 μg/L, 0.54–4.92) and MNRET (1.59 ‰, 0.78–10.92) compared to the within company controls (urinary: 0.40 μg/L, 0.16–21.3, RBC: 0.60 μg/L, 0.50–0.93,MNRET: 1.06 ‰, 0.71–2.06). When sub-dividing by company type, urinary Cr (4.61 μg/L, 1.72–69.5), Cr in RBC (1.33 μg/L, 0.95–4.98) and MNRET (1.89 μg/L, 0.78–12.92) levels were increased for workers with potential Cr(VI) exposure in bath-plating companies, and when subdividing by work task, workers engaged in process operation had increased levels of urinary Cr (8.51 μg/L, 1.71–69.5), Cr in RBC (1.33 μg/L, 0.95–4.98) and MNRET (1.89 μg/L, 0.82–12.92) levels.
Conclusion
This biomonitoring study shows that bath platers were highly exposed to Cr(VI), as suggested by relatively high levels of urinary Cr, Cr in RBC and increased levels of micronuclei. The urinary Cr concentrations were high when compared to the French biological limit value of 2.5 μg Cr/L, corresponding to the Danish occupational exposure limit of 1 μg/m3. This, in turn, indirectly suggests that additional exposure routes than via air may contribute to the exposure. For welders, no statistically significant increases compared to within company controls were observed, however, the observed urinary Cr levels were similar to the levels observed in a European study (HBM4EU), and were higher than the levels observed for welders in Sweden (SafeChrom). In spite of a high degree of self-reported and observed compliance to OSH risk prevention measures during announced visits, the biomarkers of exposure reflecting recent exposure (urinary Cr) or exposure during the last four months (Cr in RBC) may point to variation in compliance to OSH risk prevention measures in general. Reduced occupational exposure to Cr(VI) may be achieved by applying the hierarchy of controls in eliminating or substituting Cr(VI), and the use of more effective technical solutions (e.g. automation)
High-pressure conversion of ammonia additivated with dimethyl ether in a flow reactor
Full text linkThe oxidation of ammonia (NH3) mixed with dimethyl ether (DME) was investigated from experimental and modeling points of view using a quartz flow reactor with argon as bath gas from 350 K to 1225 K, for two different DME/NH3 ratios (0.05 and 0.3), three oxygen excess ratios (λ = 0.7, 1 and 3) and various pressures (1, 10, 20 and 40 bar).
The effect of pressure, oxygen stoichiometry, temperature, and DME/NH3 ratio has been analyzed on DME, NH3, NO, NO2, N2O, N2, O2, H2, HCN, CH4, CO, and CO2 concentrations.
The present study indicates that oxygen availability, DME/NH3 ratio, and pressure are important variables that shift NH3 and DME conversion to lower temperatures as their values increase. Under certain conditions, the pressure effect can avoid NO and HCN production, which would represent a benefit for pressure applications.
The main products of ammonia/dimethyl ether oxidation are N2, N2O, CO, and CO2, and under certain conditions, NO, H2, CH4, and HCN are also produced. NO2 is always detected below 5 ppm for all the conditions considered. The N2O formation is favored by increasing the O2 stoichiometry, pressure, and/or DME/NH3 ratio.
The experimental results are interpreted and discussed in terms of an updated detailed chemical kinetic mechanism, which captures, with a general good agreement, the main trends of NH3 and DME conversion under the considered conditions. Despite this, some calculated species present discrepancies with the experimental results. The main challenge is the consideration of the C-N interactions that can be present in the combustion of DME/NH3 mixtures
Interrelationships between polygenic risk scores, cognition, symptoms, and functioning in first-episode psychosis: A network analysis approach
No full textPsychopathological manifestations and cognitive impairments are core features of psychotic disorders. Polygenic risk scores (PRS) offer insights into the relationships between genetic vulnerability, symptomatology, and cognitive impairments. This study used a network analysis to explore the connections between PRS, cognition, psychopathology, and overall functional outcomes in individuals experiencing a first episode of psychosis (FEP). The study sample comprised 132 patients with FEP. Genetic data were used to construct PRS for mental disorders and cognitive traits via PRS-continuous shrinkage. We conducted comprehensive clinical and neuropsychological assessments at 2 months post-diagnosis and again at a 2-year follow-up. A network analysis was performed to generate two distinct networks and their centrality indices, encompassing 19 variables across domains such as symptoms, cognition, functioning, and PRS. Variables were grouped within related domains, and stronger relationships were observed within domains than between them. PRS for schizophrenia showed weak negative associations with attention, working memory, and verbal memory, while PRS for cognitive performance showed weak positive associations with attention. Negative symptoms were negatively associated with functioning and verbal memory at both the 2-month and 2-year assessments, as well as with social cognition at 2 years. Poor functioning was moderately related to greater severity of Positive and Negative Syndrome Scale dimensions. This study identified pathways linking PRS, cognition, symptoms, and functioning, suggesting that genetic risk may serve as a marker of vulnerability and disorder progression. The findings also highlight the importance of considering genetic predispositions alongside clinical and cognitive factors to better understand the heterogeneity of psychotic disorders
Structural and functional insights into UDP-N-acetylglucosamine-enolpyruvate reductase (MurB) from Brucella ovis
No full textThe peptidoglycan biosynthetic pathway involves a series of enzymatic reactions in which UDP-N-acetylglucosamine-enolpyruvate reductase (MurB) plays a crucial role in catalyzing the conversion of UDP-N-acetylglucosamine-enolpyruvate (UNAGEP) to UDP-N-acetylmuramic acid. This reaction relies on NADPH and FAD and, since MurB is not found in eukaryotes, it is an attractive target for the development of antimicrobials. MurB from Brucella ovis, the causative agent of brucellosis in sheep, is characterized here. The FAD cofactor in MurB of B. ovis is reduced to the hydroquinone state without semiquinone stabilization with an estimated Eox/hq of −260 mV. MurB from B. ovis catalyzes the oxidation of NADPH in a slow process that is positively influenced by the presence of the second product, UNAGEP. The crystallographic structure of the MurBox:UNAGEP complex confirms its folding into three domains and the binding of UNAGEP, positioning its enolpyruvyl group for hydride transfer from FAD. MurB shows a complex thermal unfolding pathway that is influenced by UNAGEP and NADP+, confirming its ability to bind both molecules. Molecular dynamics (MD) simulations predict that the nicotinamide of NADP+ is more stable at the active site than the enolpyruvyl of UNAGEP, and suggests that MurB can simultaneously accommodate NADPH and UNAGEP in the substrate channel, increasing overall protein-ligand flexibility. Sequence and evolutionary analyses show that MurB from B. ovis conserves all motifs predicted to be involved in catalysis within the Type IIa family
The Cuntz semigroup of a ring
Full text linkFor any ring R, we introduce an invariant in the form of a partially ordered abelian semigroup built from an equivalence relation on the class of countably generated projective modules. We call the Cuntz semigroup of the ring R. This construction is akin to the manufacture of the Cuntz semigroup of a C*-algebra using countably generated Hilbert modules. To circumvent the lack of a topology in a general ring R, we deepen our understanding of countably projective modules over R, thus uncovering new features in their direct limit decompositions, which in turn yields two equivalent descriptions of . The Cuntz semigroup of R is part of a new invariant which includes an ambient semigroup in the category of abstract Cuntz semigroups that provides additional information. We provide computations for both and in a number of interesting situations, such as unit-regular rings, semilocal rings, and in the context of nearly simple domains. We also relate our construcion to the Cuntz semigroup of a C*-algebra
Evaluation of Salt Tolerance in Four Self-Rooted Almond Genotypes for Super-High-Density Orchards Under Varying Salinity Levels
Full text linkIncreasing soil salinity threatens almond production globally, driving the need for the development of salt-tolerant cultivars. This study investigated the salt tolerance mechanisms of four self-rooted almond genotypes (Vialfas, Guara, Penta, and Avijor) under controlled conditions. Young plants were exposed to four salinity levels (0, 25, 50, and 75 mM NaCl) for 5 months. Growth parameters (trunk diameter, shoot length, fresh and dry weights), physiological responses (chlorophyll fluorescence, gas exchange, Soil–Plant Analysis Development (SPAD)), and mineral content were analyzed. Results show significant genotype-specific responses at the critical salinity threshold of 50 mM NaCl. Under these conditions, Guara and Vialfas maintained higher stem fresh weights (31.4 g and 37 g, respectively), while Avijor showed significant declines. Trunk diameter measurements revealed Vialfas’ superior performance (7 mm) compared to Guara and Penta (both around 6 mm), while Avijor exhibited the most significant reduction (5 mm). Chlorophyll fluorescence parameters indicated stress impact, with Fv/Fm values decreasing to 0.84 compared to control values of 0.87. Guara maintained higher K+/Na+ ratios in leaves (3.05) compared to Avijor (1.95), while Penta showed better Na+ exclusion ability with the lowest leaf Na+ content (0.57%). Cl− accumulation patterns also differed among genotypes, with Avijor and Vialfas showing higher leaf Cl− concentrations (0.74% and 0.73%, respectively) compared to Penta (0.44%). Genotype responses across all salinity levels revealed distinct tolerance patterns: Guara maintained growth and physiological functions across treatments, while Penta showed remarkable stability under high salinity. Vialfas exhibited vigor at low salinity but declined sharply at 75 mM NaCl. Avijor demonstrated the highest salt sensitivity. These findings highlight the genetic variability in salt tolerance among almond cultivars and identify potential sources of salt-tolerant traits for breeding programs. The study also provides insights for optimizing genotype selection and management strategies in salt-affected orchards, contributing to more sustainable almond production in challenging environments
Comparative Evaluation of Salt Tolerance in Four Self-Rooted Hazelnut (Corylus avellana L. and Corylus americana Walter) Cultivars
Full text linkRising soil salinity poses a significant challenge to hazelnut cultivation, particularly in Mediterranean regions, where the increasing use of low-quality irrigation water necessitates the identification of salt-tolerant cultivars for sustainable production. This study investigated the salt tolerance mechanisms in four hazelnut cultivars (Barcelona, Tonda di Giffoni, Tonda Gentile Romana, and Yamhill) exposed to varying NaCl concentrations (0, 25, 50, and 75 mM) over five months. This research assessed their morphological, physiological, and biochemical responses through an analysis of their growth parameters, photosynthetic efficiency, visual symptoms, and ion content. The results revealed significant genotypic variation in their salt tolerance mechanisms. Tonda di Giffoni demonstrated superior salt tolerance, maintaining a higher photosynthetic efficiency and better ion balance, particularly in K⁺/Na⁺ and Ca2⁺/Na⁺ ratios. Barcelona showed moderate tolerance at lower salinity levels but declined sharply under higher stress. Yamhill exhibited a strong survival capacity despite its poor photosynthetic performance, while Tonda Gentile Romana proved most sensitive to salinity stress. All the cultivars showed a significant biomass reduction, with their fresh and dry weights decreasing by over 80% at 75 mM NaCl. Leaf chloride concentrations dramatically increased, reaching levels 481% higher than those in the control conditions. This study identifies Tonda di Giffoni as the most suitable cultivar for moderately saline conditions and provides insights into hazelnut salt tolerance mechanisms, contributing valuable information for breeding programs and cultivation strategies in salt-affected regions
La formación que se debe proporcionar a los directivos y empleados de la persona jurídica como elemento esencial del criminal compliance program
Full text linkEn el apartado quinto del art. 31 bis CP se recogen los seis requisitos que debe cumplir el modelo de organización y gestión para que se pueda considerar que es idóneo y ha sido ejecutado con eficacia. Sin embargo, no se alude en ninguno de estos requisitos a la necesidad de que se proporcione formación a los directivos y empleados de la empresa u organización en materia de criminal compliance. Por ello, cabe preguntarse si realmente se debería eximir de responsabilidad «penal» a una persona jurídica si no se ha preocupado de que sus trabajadores reciban formación adecuada en esta materia
La concreción del deber objetivo de cuidado en el desarrollo de la actividad médico-quirúrgica curativa a la luz de los avances de los sistemas de inteligencia artificial
Full text linkEn este trabajo nos proponemos analizar el papel que desempeña la Inteligencia Artificial en la definición del deber objetivo de cuidado en la realización de una actividad médico-quirúrgica curativa, aspecto que es imprescindible tratar previamente para poder afirmar la creación de un riesgo típicamente desaprobado que permite definir la existencia de un desvalor de la acción en el delito imprudente. Las cuestiones que se abordan en este contexto son diversas: ¿cómo influyen los sistemas de Inteligencia Artificial en la determinación del deber objetivo de cuidado en una intervención médico-quirúrgica curativa?; ¿los sistemas de Inteligencia Artificial pueden reemplazar el juicio clínico del personal facultativo?; ¿debe responder el personal sanitario de los errores de la Inteligencia Artificial cuando ha adoptado una decisión con base en la información proporcionada por ella misma? La respuesta a estos interrogantes nos ha conducido a la revisión del alcance del límite social de los medios y modos de ejecución de las actividades médico-quirúrgica curativas en el marco del desarrollo actual de la Inteligencia Artificial, con la finalidad de implementar sus tecnologías de una manera responsable y con un equilibrio necesario entre la innovación tecnológica y la seguridad del paciente