Workers particularly sensitive to cardiovascular risk

Background: Of the 607 fatal occupational accidents that occurred in Spain in 2016, 37.9% were due to ischemic heart disease and stroke. Working conditions such as night work, noise or respiratory contaminants were associated with a higher cardiovascular incidence. The aim of the present study was to assess whether health surveillance in workers exposed to these conditions should include assessment of cardiovascular risk.Subjects and methods: A cross-sectional study was conducted in 680 workers in a public administration. The qualification of working conditions was obtained from the company risk assessment and from personal, anthropometric and analytical data, which allowed the assessment of cardiovascular risk in the medical examination performed in 2015.Results: 30.1% of the sample were exposed to these working conditions, with significant differences by sex (37% in men, 11.9% in women, p<0.05). According to REGICOR, 13.2% of those exposed were classified as particularly sensitive to cardiovascular risk.Conclusions: A large percentage of workers are exposed to TC related to a greater prevalence of cardiovascular pathology. The percentage of workers classified as especially sensitive to cardiovascular risk among those exposed suggests that this risk should be assessed in occupational health surveillance when there are working conditions related to cardiovascular pathology

Covariation in oxidative stress markers in the blood of nestling and adult birds

Interest in the imbalance between the production of reactive oxygen species and the state of the antioxidant machinery—that is, oxidative stress—has recently grown among comparative physiologists and evolutionary/behavioral ecologists. The number and types of markers used to estimate oxidative stress is, however, under debate. The study of covariation among these markers is necessary to better interpret the information content of each independent variable. Here, the covariation in levels of 10 blood parameters in a group of zebra finches (Taeniopygia guttata) as nestlings and adults was analyzed across a large data set. Total glutathione levels in erythrocytes were negatively correlated with plasma carotenoid values in nestlings only, supporting the implication of carotenoids in the antioxidant machinery during a particularly stressful period of life. Plasma lipid levels (triglycerides [TRGs]) as well as plasma antioxidant capacity—the latter tested with and without control for uric acid levels—showed individual consistency with age. Plasma TRG and uric acid levels were strongly correlated with plasma lipid peroxidation and antioxidant capacity, respectively, suggesting an influence of recent intake or mobilization of energy stores on these variables. The meaning of oxidative stress markers, whether corrected or uncorrected for levels of nutritional metabolites, remains to be explored. Experiments manipulating diet composition and oxidative stress are necessary to confirm or reject the hypothesized causalities.A.A.R.-H. was funded by a Formación de Personal de Investigación grant (BES-2010-035013; Ministerio de Economía y Competitividad [MINECO], Spanish government). Financial support was obtained from the projects CGL-2009-10883-C02-02 and CGL2012-40229-C02-01 (MINECO).Peer Reviewe

The level of an intracellular antioxidant during development determines the adult phenotype in a bird species: a potential organizer role for glutathione

Life-history traits are often involved in trade-offs whose outcome would depend on the availability of resources but also on the state of specific molecular signals. Early conditions can influence trade-offs and program the phenotype throughout the lifetime, with oxidative stress likely involved in many taxa. Here we address the potential regulatory role of a single intracellular antioxidant in lifehistory trade-offs. Blood glutathione levels were reduced in a large sample of birds (zebra finch Taeniopygia guttata) during development using the synthesis inhibitor buthionine sulfoximine (BSO). Results revealed several modifications in the adult phenotype. BSO-treated nestlings showed lower glutathione and plasma antioxidant levels. In adulthood, BSO birds endured greater oxidative damage in erythrocytes but stronger expression of a sexual signal. Moreover, adult BSO females also showed weaker resistance to oxidative stress but were heavier and showed better body condition. Results suggest that low glutathione values during growth favor the investment in traits that should improve fitness returns, probably in the form of early reproduction. Higher oxidative stress in adulthood may be endured if this cost is paid later in life. Either the presence of specific signaling mechanisms or the indirect effect of increased oxidative stress can explain our findings.Ministerio de Economía y Competitividad [MINECO], Spain). Financial support was obtained from the projects CGL-2009-10883-C02-02 and CGL2012-40229-C02-01 (MINECO).Peer Reviewe

Experimental and numerical analysis of the influence of drill point angle when drilling biocomposites

Biocomposites are promising materials for traditional composites replacement in specific applications due to their interesting properties and sustainability. Although the composite components are manufactured near net shape, some machining operations, commonly drilling, are commonly required prior to mechanical joining of the components. Tool geometry, mainly the point angle of the drill, strongly affects the performance of the drilling process of composites in terms of machining induced damage. The aim of this work is analyzing the influence of the point angle of the drill on the damage generated during drilling of 100% biodegradable composite, using both numerical and experimental approaches. The novelty of the work relies on the lack of studies of drilling 100% biodegradable composites. The influence of the point angle on the thrust forces and hence in the machining induced damage was demonstrated.The authors acknowledge the financial support to the Ministry of Economy and Competitiveness of Spain and FEDER program through the projects DPI2017-89197-C2-1-R and DPI2017-89197-C2-2-R

Analysis of orthogonal cutting of biocomposites

The use of 100% biodegradable composites in the industry is increasing significantly over the years, mainly due to their excellent properties as well as to the growing ecologic concern. However, after their manufacture, the composite pieces do not always have the final shape, requiring subsequent processing operations, usually drilling and trimming. The performance of cutting processes on fully biodegradable composites are often limited by induced damage as fraying and delamination. This type of phenomena is related, among others, with the cutting parameters and geometries of the tool. Orthogonal cutting is a simplified process that could help in the understanding of damage mechanisms, it is a well-known technique in traditional composites but its use in biocomposites is an almost unexplored field. This work focuses on flax/PLA 100% biodegradable woven composites. The specimens have been manufactured with different angles of orientation, ranging from 0° to 60°, being subjected to orthogonal cutting in a special machine developed for that purpose that allows to develop cutting tests with linear displacement at high speeds. Damage extension, failure modes, and cutting forces are analyzed allowing the extraction of important experimental information.Authors gratefully acknowledges the financial support to the Ministry of Economy and Competitiveness of Spain and FEDER program through the project DPI2017-89197-C2-1-R

Energy absorption and residual bending behavior of biocomposites bumper beams

This paper presents and analyzes the behavior of bumper beams made of PLA/flax composites subjected to low velocity impacts. The relevance of this material resides in the biodegradability of both fibers and matrix. Moreover, the after-impact behavior of this composite is excellent due to the absence of delamination. Impact tests have been performed using a drop weight tower within the range of impact energies 5 J ≤ Eimp ≤ 73 J. The experimental setup enabled the measuring of impact velocity, residual velocity, load-time history and failure mode. Results show that damage generated during impact produces a significant reduction of residual stiffness but the residual strength is not affected by damage generated in the range of the applied impact energies considered

Modelling thermal effects in machining of carbon fiber reinforced polymer composites

Machining-induced damage is commonly observed when manufacturing components based on carbon fiber reinforced polymer (CFRP) composites. Despite the importance of thermal effects in machining CFRPs, this problem has been poorly analyzed in the literature. Predictive tools are not available for thermal phenomena involved during cutting, while only few experimental studies have been found. In this paper, a three-dimensional (3D) finite element model of orthogonal machining of CFRPs including thermal effects is presented. Predicted thermal and mechanical intralaminar damage showed strong influence of fiber orientation. Thermally affected area was larger than mechanically damaged zone. This fact confirms the importance of accounting for thermal effects when modelling CFRP machining.The authors acknowledge the financial support for the work to the Ministry of Economy and Competitiveness of Spain under the projects DPI2011-25999 and DPI2010-15123.Publicad

Mitochondrial Sulfide Detoxification Requires a Functional Isoform O-Acetylserine(thiol)lyase C in Arabidopsis thaliana

In non-cyanogenic species, the main source of cyanide derives from ethylene and camalexin biosyntheses. In mitochondria, cyanide is a potent inhibitor of the cytochrome c oxidase and is metabolised by the β-Cyanoalanine synthase CYS-C1, catalysing the conversion of cysteine and cyanide to hydrogen sulfide and β- cyanoalanine. The hydrogen sulfide released also inhibits the cytochrome c oxidase and needs to be detoxified by the O-acetylserine(thiol)lyase mitochondrial isoform, OAS-C, which catalyses the incorporation of sulfide to O-acetylserine to produce cysteine, thus generating a cyclic pathway in the mitochondria. The loss of functional OAS-C isoforms causes phenotypic characteristics very similar to the loss of the CYS-C1 enzyme, showing defects in root hair formation. Genetic complementation with the OAS-C gene rescues the impairment of root hair elongation restoring the wild type phenotype. The mitochondria compromise their capacity to proper detoxify cyanide and the resulting sulfide because the latter cannot re-assimilate into cysteine in the oas-c null mutant. Consequently, we observe an accumulation of sulfide and cyanide and of the alternative oxidase, which is unable to prevent the production of reactive oxygen species probably due to the accumulation of both toxic molecules. Our results allow us to suggest that the significance of OAS-C is related with its role in the proper sulfide and cyanide detoxification in mitochondria.Ministerio de Ciencia e Innovación BIO2010-15201Junta de Andalucía BIO–27