This article concerns the study of post-impact damage propagation in two thin hybrid woven composite laminates loaded in tension. Low velocity normal drop weight impact tests are first performed. ...Post-impact quasi-static tensile tests are then carried out and monitored by Digital Image Correlation. The influence of the impact energy variation on the fracture surfaces and the residual strength is studied. In order o have a better understanding of the mechanisms involved into the hybrid laminates, four monomaterial sample configurations are also tested. When the damage after impact is barely visible, the sample behaves as a non-impacted sample. When the damage is visible, it propagates whatever the impact energy. The damage grows in the direction perpendicular to the loading for all the monomaterial laminates while two different damage scenarios are observed for the hybrid laminates. The residual strength evolves in three steps depending on the impact energy: first a very low decrease, then an important drop and finally a plateau.
Low plasma 25-hydroxyvitamin D (25OHD) concentration is associated with high arterial blood pressure and hypertension risk, but whether this association is causal is unknown. We used a mendelian ...randomisation approach to test whether 25(OH)D concentration is causally associated with blood pressure and hypertension risk.
In this mendelian randomisation study, we generated an allele score (25OHD synthesis score) based on variants of genes that affect 25(OH)D synthesis or substrate availability (CYP2R1 and DHCR7), which we used as a proxy for 25(OH)D concentration. We meta-analysed data for up to 108 173 individuals from 35 studies in the D-CarDia collaboration to investigate associations between the allele score and blood pressure measurements. We complemented these analyses with previously published summary statistics from the International Consortium on Blood Pressure (ICBP), the Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) consortium, and the Global Blood Pressure Genetics (Global BPGen) consortium.
In phenotypic analyses (up to n=49 363), increased 25(OH)D concentration was associated with decreased systolic blood pressure (β per 10% increase, −0·12 mm Hg, 95% CI −0·20 to −0·04; p=0·003) and reduced odds of hypertension (odds ratio OR 0·98, 95% CI 0·97–0·99; p=0·0003), but not with decreased diastolic blood pressure (β per 10% increase, −0·02 mm Hg, −0·08 to 0·03; p=0·37). In meta-analyses in which we combined data from D-CarDia and the ICBP (n=146 581, after exclusion of overlapping studies), each 25(OH)D-increasing allele of the synthesis score was associated with a change of −0·10 mm Hg in systolic blood pressure (−0·21 to −0·0001; p=0·0498) and a change of −0·08 mm Hg in diastolic blood pressure (−0·15 to −0·02; p=0·01). When D-CarDia and consortia data for hypertension were meta-analysed together (n=142 255), the synthesis score was associated with a reduced odds of hypertension (OR per allele, 0·98, 0·96–0·99; p=0·001). In instrumental variable analysis, each 10% increase in genetically instrumented 25(OH)D concentration was associated with a change of −0·29 mm Hg in diastolic blood pressure (−0·52 to −0·07; p=0·01), a change of −0·37 mm Hg in systolic blood pressure (−0·73 to 0·003; p=0·052), and an 8·1% decreased odds of hypertension (OR 0·92, 0·87–0·97; p=0·002).
Increased plasma concentrations of 25(OH)D might reduce the risk of hypertension. This finding warrants further investigation in an independent, similarly powered study.
British Heart Foundation, UK Medical Research Council, and Academy of Finland.
The effects of nitrate supply on growth, pigments, mycosporine‐like amino acids (MAAs), C:N ratios and carrageenan yield were investigated in Mazzaella laminarioides cultivated under solar radiation. ...This species is economically important in southern Chile where an increase of nitrogen in coastal waters is expected as a consequence of salmon aquaculture activity. Apical segments were cultivated in enriched seawater with five different NO3− concentrations (0, 0.09, 0.18, 0.38 and 0.75 mm) during 18 days. Although phycoerythrin and phycocyanin content, as well as C:N ratios, were reduced in the control treatment (without NO3− supply), when compared to NO3− treatments, total MAA concentration, carrageenan yield and growth rates were similar in all tested conditions. Nevertheless, during the experiment, an important synthesis of mycosporine‐glycine took place in a nitrate concentration‐dependent manner, with accumulation being saturated around 0.18 mm of nitrate. These results indicate that exposure to high NO3− concentration of more than 100 times the values observed in the nature did not impair the photoprotection system, as determined by MAAs, nor did it have a deleterious effect on growth or carrageenan yield of M. laminarioides, a late successional species from Chile.
The effect of NO3− on Mazzaella laminarioides was evident by the preferential accumulation of mycosporine‐glycine, rather than total MAAs. The fact that mycosporine‐glycine, but not total MAAs, was increased could have resulted from interconversions among different MAAs. Synthesis and accumulation of compounds with antioxidant activities, such as mycosporine‐glycine, could play an important ecological role.
Natural history after a first episode of acute pancreatitis Suria, C.; García, T.; Varela, J.M. ...
Pancreatology : official journal of the International Association of Pancreatology (IAP) ... et al.,
11/2023, Letnik:
23, Številka:
7
Journal Article
The addition of a dissipation step to the widely used McCormack numerical scheme is proposed for solving one-dimensional open-channel flow equations. The extra step is devised according to the theory ...of total variation diminishing (TVD) schemes that are capable of capturing sharp discontinuities without generating the spurious oscillations that more classical methods do. At the same time, the extra step does not introduce any additional difficulty for the treatment of the source terms of the equations. Results from several computations are presented and comparison with the analytical solution for some test problems is shown. The overall performance of the method can be considered very good, and it allows for accurate open-channel flow computations involving hydraulic jumps and bores.
An experimental study of Cd(II) transport through a polymer-immobilised liquid membrane (PILM) using Cyanex 923 as carrier has been performed. Factors affecting cadmium permeability, such as stirring ...speed of the source phase, extractant concentration in the membrane phase, metal, HCl and H
3PO
4 concentrations in the source phase, etc., have been analyzed. Optimal experimental conditions for Cd(II) permeation and recovery (
P
Cd=34.3 μm/s and 85.8% recovery) were obtained after 3 h using membranes containing 30% v/v Cyanex 923 dissolved in xylene, using a microporous Durapore GVHP support, with water as stripping agent and initial source phase of 0.89 μM Cd, and 100 g/L each of HCl and H
3PO
4.
This article concerns the modelling of post-impact damage propagation in thin woven composite laminates. Simulations of low velocity impacts and post-impact quasi-static tension are performed on ...single-material and hybrid laminates. The modelling is based on the semi-continuous approach implemented into the explicit finite element code RADIOSS. The bundles are modelled with rod elements and a specific damageable shell element is used to stabilize this truss structure. Improvements are brought with the introduction of a compressive failure criterion for the rod elements and the development of a pseudo-plastic law with damaging for in in-plane shear. The results provided by the modelling well correlates the experimental observations in terms of damage propagation and load-displacement curves for all the configurations studied.
The control of the Ca(2+)-ATPase gene (LCA1) that encodes two different membrane-located isoforms by two antagonic phytohormones, ABA and IAA, has been investigated. Strikingly both the growth ...regulators induce the LCA1 expression. By using a protoplast transient system, the cis-acting DNA elements responding to both, abiotic stress (ABA) and normal development (IAA), are dissected. ABA triggered a 4-fold increase in the GUS-activity. A single ACGT motif responsible for most of the LCA1 mRNA induction was localized at an unexpectedly large distance (1577 bp) upstream of the translational start. In the case of IAA, although there is a TGTCTC sequence that is known to be an important cis-acting element, two TGA motifs play a more critical role. It is proposed that the Ca(2+)-ATPase isoforms might intervene in the generation of specific Ca(2+) signals by restoring steady-state Ca(2+) levels, modulating both frequency and amplitude of Ca(2+) waves via wave interference.
Nature Communications 7: Article number: 11106 (2016); Published: 26 April 2016; Updated: 3 June 2016 The original version of this Article contained an error in the spelling of the author Milka ...Koupenova, which was incorrectly given as Milka Koupenova-Zamor. This has now been corrected in both the PDF and HTML versions of the Article.
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