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International audience; In this paper, buckling and free vibration of imperfect, functionally graded beams, including porosities, are investigated, using a higher order shear strain theory. Due to defects during the manufacturing process, micro porosities may appear in the material, hence the appearance of this imperfection in the structure. The material properties of the beams are assumed to vary regularly, with power and sigmoid law, in the direction of thickness. A novel porosity distribution affecting the functionally graded volume fraction is presented. For the compact formulation used for cementite-based materials and already used in P-FGM, we have adapted it for the distribution of S-FGM. The equations of motion in the FG beam are derived using Hamilton's principle. The boundary conditions for beam FG are assumed to be simply supported. Navier's solution is used to obtain the closed form solutions of the FG beam. The numerical results of this work are compared with those of other published research to verify accuracy and reliability. The comparisons of different shear shape functions, the influence of porosity, thickness and inhomogeneity parameters on buckling and free vibration of the FG beam are all discussed. It is established that the present work is more precise than certain theories developed previously. Copyright © 2022 Techno-Press, Ltd.

Review of scientific instruments 92(2), 023907 (2021). doi:10.1063/5.0035529, Dynamic Light Scattering (DLS) and Small-Angle Neutron Scattering (SANS) are two key tools to probe the dynamic and static structure factors, respectively, in soft matter. Usually, DLS and SANS measurements are performed separately, in different laboratories, on different samples, and at different times. However, this methodology has particular disadvantages for a large variety of soft materials, which exhibit a high sensitivity to small changes in fundamental parameters, such as waiting times, concentration, pH, and ionic strength. Here, we report on a new portable DLS-SANS apparatus that allows one to simultaneously measure both the microscopic dynamics (through DLS) and the static structure (through SANS) on the same sample. The apparatus has been constructed as a collaboration between two laboratories, each an expert in one of the scattering methods, and was commissioned on the LOQ and ZOOM SANS instruments at the ISIS Pulsed Neutron and Muon Source, U.K., Published by American Institute of Physics, [S.l.]

Marine microorganisms play a fundamental role in the global carbon cycle by mediating the sequestration of organic matter in ocean waters and sediments. A better understanding of how biological factors, such as microbial community composition, influence the lability and fate of organic matter is needed. Here, we explored the extent to which organic matter remineralization is influenced by species-specific metabolic capabilities. We carried out aerobic time-series incubations of Guaymas Basin sediments to quantify the dynamics of carbon utilization by two different heterotrophic marine isolates (Vibrio splendidus 1A01; Pseudoalteromonas sp. 3D05). Continuous measurement of respiratory CO2 production and its carbon isotopic compositions (13C and 14C) shows species-specific differences in the rate, quantity and type of organic matter remineralized. Each species was incubated with hydrothermally-influenced versus unimpacted sediments, resulting in a ~2-fold difference in respiratory CO2 yield across the experiments. Genomic analysis indicated that the observed carbon utilization patterns may be attributed in part to the number of gene copies encoding for extracellular hydrolytic enzymes. Our results demonstrate that the lability and remineralization of organic matter in marine environments is not only a function of chemical composition and/or environmental conditions, but also a function of the microorganisms that are present and active.

To overcome the deficit in natural resources and meet the ever-increasing demand in the field of construction, waste recovery channels represent significant interests in a sustainable development perspective. The valorization of the dredged silt at the Bouhanifia dam, located in the north-west of Algeria, for its use in the brick-making technology is the way we have followed. In the context of decision support in order to have an adequate chemical analysis of a clay used in the manufacture of red brick, the use of the Electre III multi-criteria method, developed in hybridization with the Genetic Algorithm, is recommended, which makes it possible to establish a ranking of the different parameters, within a set of potential actions constituting a range of possible solutions for the choice of the best chemical composition of the mud from the dredging of the Bouhanifia dam.

Crude oil has been part of the marine environment for millions of years, and microbes that use its rich source of energy and carbon are found in seawater, sediments, and shorelines from the tropics to the polar regions. Catastrophic oil spills stimulate these organisms to "bloom" in a reproducible fashion, and although oil does not provide bioavailable nitrogen, phosphorus or iron, there are enough of these nutrients in the sea that when dispersed oil droplets dilute to low concentrations these low levels are adequate for microbial growth. Most of the hydrocarbons in dispersed oil are degraded in aerobic marine waters with a half-life of days to months. In contrast, oil that reaches shorelines is likely to be too concentrated, have lower levels of nutrients, and have a far longer residence time in the environment. Oil that becomes entrained in anaerobic sediments is also likely to have a long residence time, although it too will eventually be biodegraded. Thus, data that encompass everything from the ecosystem to the molecular level are needed for understanding the complicated process of petroleum biodegradation in marine environments.

International audience

Gastric variceal bleeding is an uncommon, serious complication of portal hypertension. The significant morbidity and mortality resulting from bleeding from gastric varices presents a challenge for gastroenterologists. The management of this complication has not been standardized. Although transjugular intrahepatic portosystemic shunt (TIPS) is used in many centres to treat gastric varices, endoscopic treatment with the tissue glue cyanoacrylate (N-butyl-2-cyanoacrylate) has been used successfully in many countries for 20 years and is considered, by many clinicians, to be the optimal initial treatment for bleeding gastric varices (1). Despite the widespread use of cyanoacrylate, there are still controversies in the literature regarding its use. The present article deals with the indications, technique, preparation, catheter use, long-term results and cost-effectiveness of the procedure. Close attention to these recommendations can result in successful and safe usage of the tissue glue. The endoscopy unit planning to perform gastric variceal glueing should have a detailed nursing protocol established before performing this procedure.

The effect of specific nutrients on Salmo trutta caspius intestinal variation are practically unknown. The purpose of this work was to study the effects of different levels (0, 0.25 and 0.5%) of dietary nucleotide that added in control meal, on several segment of intestinal structure of Caspian salmon juvenile with average001/0± 26/12 g weight (average length 11/1±0/002). This trial was achieved in fiber glass 300 liter fresh water tank with 35 fish in each one. Fish cultured in 8 weeks and experiment has done on fish with average 26 g weight. 6 fish from each treatment captured, sacrificed and immediately gastro intestinal tract fixed by immersion into Bouin solution for histology. Then histological sections of 4 mm obtained, stained with Hematoxiline-Fushin and investigated. Results indicate that in duodenum nucleotide has a significantly (P

This research was carried out for 10 successive weeks (2 weeks for adaptation and 8 weeks for culture) in summer 2008 at Abzisytan Shrimp Hatchery Center in Bushehr province. The effects of dietary nucleotides at 5 levels including 0.0% (control), 0.15%, 0.25%, 0.35% and 0.5% on the growth performance and whole-body composition of Epinephelus coioides was investigated. Juvenile fish specimens with average weight of 10.70±0.29g were fed by experimental diets for 8 weeks. The trial was carried out in 300 liter fiberglass tanks. The highest protein content was observed in 0.15% diet nucleotide and the highest fat in 0.15% and 0.25% diet nucleotide which showed significant difference with the control group (P

The estimated worldwide incidence of Plasmodium falciparum malaria is about 500 million cases a year. In tropical areas, the dramatic increase of resistance to most antimalarial drugs is directly responsible for persistent widespread high endemicity and related morbidity. The search to identify new drug targets and agents is a high priority. However the value of standard pharmacological research methods is greatly diminished by technical problems involving in vitro and in vivo modeling of malaria infection. In recent decades new mathematical tools have been developed to predict drug properties and to estimate biological activity in silico. Various approaches have been proposed based on 2D or 3D descriptions of the chemical structure of the drug and target followed by mathematical and statistical characterization of their interaction. These techniques are now widely used in medicinal chemistry and have proven their efficacy for screening the anti-malarial activity of numerous molecules in large databases and for virtual synthesis. Incorporating new knowledge from the genomic studies of Plasmodium has markedly increased the performance and range of application of these tools for identifying new drug targets against malaria.