Micromechanical Properties of Injection-Molded Starch–Wood Particle Composites

The micromechanical properties of injection molded starch–wood particle composites were investigated as a function of particle content and humidity conditions. The composite materials were characterized by scanning electron microscopy and X-ray diffraction methods. The microhardness of the composites was shown to increase notably with the concentration of the wood particles. In addition,creep behavior under the indenter and temperature dependence were evaluated in terms of the independent contribution of the starch matrix and the wood microparticles to the hardness value. The influence of drying time on the density and weight uptake of the injection-molded composites was highlighted. The results revealed the role of the mechanism of water evaporation, showing that the dependence of water uptake and temperature was greater for the starch–wood composites than for the pure starch sample. Experiments performed during the drying process at 70°C indicated that the wood in the starch composites did not prevent water loss from the samples.Peer reviewe

Severe plastic deformation for producing superfunctional ultrafine-grained and heterostructured materials: An interdisciplinary review

Ultrafine-grained and heterostructured materials are currently of high interest due to their superior mechanical and functional properties. Severe plastic deformation (SPD) is one of the most effective methods to produce such materials with unique microstructure-property relationships. In this review paper, after summarizing the recent progress in developing various SPD methods for processing bulk, surface and powder of materials, the main structural and microstructural features of SPD-processed materials are explained including lattice defects, grain boundaries and phase transformations. The properties and potential applications of SPD-processed materials are then reviewed in detail including tensile properties, creep, superplasticity, hydrogen embrittlement resistance, electrical conductivity, magnetic properties, optical properties, solar energy harvesting, photocatalysis, elec- trocatalysis, hydrolysis, hydrogen storage, hydrogen production, CO$_ 2$ conversion, corrosion resistance and biocompatibility. It is shown that achieving such properties is not limited to pure metals and conventional metallic alloys, and a wide range of materials are currently processed by SPD, including high-entropy alloys, glasses, semiconductors, ceramics and polymers. It is particularly emphasized that SPD has moved from a simple metal processing tool to a powerful means for the discovery and synthesis of new superfunctional metallic and nonmetallic materials. The article ends by declaring that the borders of SPD have been extended from materials science and it has become an interdisciplinary tool to address scientific questions such as the mechanisms of geological and astronomical phenomena and the origin of life

Severe plastic deformation for producing superfunctional ultrafine-grained and heterostructured materials: An interdisciplinary review

Ultrafine-grained and heterostructured materials are currently of high interest due to their superior mechanical and functional properties. Severe plastic deformation (SPD) is one of the most effective methods to produce such materials with unique microstructure-property relationships. In this review paper, after summarizing the recent progress in developing various SPD methods for processing bulk, surface and powder of materials, the main structural and microstructural features of SPD-processed materials are explained including lattice defects, grain boundaries and phase transformations. The properties and potential applications of SPD-processed materials are then reviewed in detail including tensile properties, creep, superplasticity, hydrogen embrittlement resistance, electrical conductivity, magnetic properties, optical properties, solar energy harvesting, photocatalysis, electrocatalysis, hydrolysis, hydrogen storage, hydrogen production, CO2 conversion, corrosion resistance and biocompatibility. It is shown that achieving such properties is not limited to pure metals and conventional metallic alloys, and a wide range of materials are currently processed by SPD, including high-entropy alloys, glasses, semiconductors, ceramics and polymers. It is particularly emphasized that SPD has moved from a simple metal processing tool to a powerful means for the discovery and synthesis of new superfunctional metallic and nonmetallic materials. The article ends by declaring that the borders of SPD have been extended from materials science and it has become an interdisciplinary tool to address scientific questions such as the mechanisms of geological and astronomical phenomena and the origin of life

A NOVEL STRATEGY FOR CORRECTION OF LIPID PROFILES VIA MATRICARIA CHAMOMILLA L

Statins which are most useful in reducing blood fat have a chemical combination and present various side effects. Identifying some plants with positive effects on reducing blood fat can be a great alternative to these chemical drugs. The current study has been carried out to compare the effects of hydroalcoholic extract of Matricaria chamomilla on the serum lipid profile in hypercholesterolemic rats. Twenty-five male Wistar Rats, ranging in weight from 150 to 180 grams, were assigned to five groups: the control group received an ordinary dietary regimen, the sham group was fed on a high cholesterol (2) dietary regimen, experimental groups 1, 2 and 3 were given an ordinary nutrition plus chamomilla extract and Lovastatin dosages equal to 0.55 mg/ml, 1.1 mg/ml and 10 mg/kg were also, respectively, administered. Blood samples were taken on the first and the last days of the study period. To determine the blood's lipid profile and the serum cholesterol concentration, LDL-c, HDL-c and TG were measured and the results obtained for the groups were compared. The data were analyzed in SPSS 16 software. The results of the current research paper indicated that the treatment with 1.1 mg/ml chamomile hydroalcoholic extract and 10 mg/kg lovastatin significantly reduced (P<0.001) the total serum cholesterol concentration, LDL-c and TG in experimental hypercholesterolemic groups 2 and 3 as compared to the Sham Group. Also, it was found causing a significant increase in serum HDL-c in experimental hypercholesterolemic groups 2 and 3 in contrast to the Sham Group (P<0.001 and P<0.05, respectively). The mean weight scores of the Sham group and experimental group 1 were demonstrative of a significant increase in respect to control group (P<0.001 and P<0.01, respectively). The present study showed that the use of chamomile extract in hypercholesterolemic rats can bring about clearly discernible hypocholesterolemic effects and cause considerable and desirable effects on the serum lipid profile

Using concentration gradients to examine the effects of Al, Ga and Sn additions on the low-activation VCrMnFe system

A critical design criterion for future fusion reactor components is low activation. The equiatomic multi-principal element alloy VCrMnFe is comprised solely of low activation elements and forms a single-phase solid solution at temperatures over 1000 °C. However, at lower temperatures it forms detrimental sigma phase. In this work, compositional gradients of Ga, Sn or Al were induced in VCrMnFe using only a furnace to investigate their effect on intermetallic formation. By examining how the microstructure changed across a region with varying composition, phase stability limits could be assessed. For example, all three elements were found to prevent sigma phase from forming within the alloy when they were present at relatively low concentrations (2–5 at%). Al was found to be the most promising addition (in terms of not causing embrittlement), and the approach used enabled the characterisation of the VCrMnFe–Al pseudo binary phase diagram up to 50 at% Al after heat treatment of 800 °C/240 h followed by ageing at 600 °C/240 h, with numerous ordered phases found using electron diffraction. The level of Al addition required to suppress the sigma phase has been identified more precisely, which will be useful for future alloy development work

Hydrogen storage in TiVCr(Fe,Co)(Zr,Ta) multi-phase high-entropy alloys

High-entropy alloys (HEAs) have a great potential in hydrogen storage applications. Developing an alloy showing remarkable hydrogen sorption capacity, close to ambient temperature without activating is a significant challenge for solid-state hydrogen storage. The present investigation was conducted to develop HEAs to satisfy these requirements. Accordingly, four novel equiatomic TiVCrFeTa, TiVCrFeZr, TiVCrCoTa and TiVCrCoZr HEAs were designed, fabricated and characterized to address their capability for hydrogen storage application. Alloy design was accomplished based on empirical relations and thermodynamic calculations in order to obtain a microstructure containing both BCC and Laves phases using elements with different affinity to hydrogen. The thermodynamic calculations through CALPHAD predicted the presence of BCC/B2 phase together with C14 and C15 Laves phases in all designed alloys which was in good agreement with experimental analyses. Studies on hydrogen storage properties revealed that all alloys, except for TiVCrFeZr, are able to absorb hydrogen at 294 K and 30 bar without any activation process at a short incubation time and noted HEA needed activation process at 573 K under 30 bar of hydrogen. The results revealed that after activation, TiVCrFeZr and TiVCrCoZr alloys containing high volume fraction of Laves phase (~40%) displayed the highest absorption capacity, with 2.3 and 1.6 wt% of hydrogen, respectively, at 294 K and 30 bar. In addition, the PCT curves proposed formation of solid solution of hydrides in TiVCrFeTa and TiVCrCoTa alloys at room temperature, however, TiVCrFeZr and TiVCrCoZr alloys provide a plateau region illustrating typical transition during hydrogen absorption. This study is a step forward to understanding necessities for developing advanced materials for hydrogen storage

Seasonal plasticity of cognition and related biological measures in adults with and without Alzheimer disease: Analysis of multiple cohorts.

BackgroundThere are few data concerning the association between season and cognition and its neurobiological correlates in older persons-effects with important translational and therapeutic implications for the diagnosis and treatment of Alzheimer disease (AD). We aimed to measure these effects.Methods and findingsWe analyzed data from 3,353 participants from 3 observational community-based cohort studies of older persons (the Rush Memory and Aging Project [MAP], the Religious Orders Study [ROS], and the Minority Aging Research Study [MARS]) and 2 observational memory-clinic-based cohort studies (Centre de Neurologie Cognitive [CNC] study at Lariboisière Hospital and the Sunnybrook Dementia Study [SDS]). We performed neuropsychological testing and, in subsets of participants, evaluated cerebrospinal fluid AD biomarkers, standardized structured autopsy measures, and/or prefrontal cortex gene expression by RNA sequencing. We examined the association between season and these variables using nested multiple linear and logistic regression models. There was a robust association between season and cognition that was replicated in multiple cohorts (amplitude = 0.14 SD [a measure of the magnitude of seasonal variation relative to overall variability; 95% CI 0.07-0.23], p = 0.007, in the combined MAP, ROS, and MARS cohorts; amplitude = 0.50 SD [95% CI 0.07-0.66], p = 0.017, in the SDS cohort). Average composite global cognitive function was higher in the summer and fall compared to winter and spring, with the difference equivalent in cognitive effect to 4.8 years' difference in age (95% CI 2.1-8.4, p = 0.002). Further, the odds of meeting criteria for mild cognitive impairment or dementia were higher in the winter and spring (odds ratio 1.31 [95% CI 1.10-1.57], p = 0.003). These results were robust against multiple potential confounders including depressive symptoms, sleep, physical activity, and thyroid status and persisted in cases with AD pathology. Moreover, season had a marked effect on cerebrospinal fluid Aβ 42 level (amplitude 0.30 SD [95% CI 0.10-0.64], p = 0.003), which peaked in the summer, and on the brain expression of 4 cognition-associated modules of co-expressed genes (m6: amplitude = 0.44 SD [95% CI 0.21-0.65], p = 0.0021; m13: amplitude = 0.46 SD [95% CI 0.27-0.76], p = 0.0009; m109: amplitude = 0.43 SD [95% CI 0.24-0.67], p = 0.0021; and m122: amplitude 0.46 SD [95% CI 0.20-0.71], p = 0.0012), which were in phase or anti-phase to the rhythms of cognition and which were in turn associated with binding sites for several seasonally rhythmic transcription factors including BCL11A, CTCF, EGR1, MEF2C, and THAP1. Limitations include the evaluation of each participant or sample once per annual cycle, reliance on self-report for measurement of environmental and behavioral factors, and potentially limited generalizability to individuals in equatorial regions or in the southern hemisphere.ConclusionsSeason has a clinically significant association with cognition and its neurobiological correlates in older adults with and without AD pathology. There may be value in increasing dementia-related clinical resources in the winter and early spring, when symptoms are likely to be most pronounced. Moreover, the persistence of robust seasonal plasticity in cognition and its neurobiological correlates, even in the context of concomitant AD pathology, suggests that targeting environmental or behavioral drivers of seasonal cognitive plasticity, or the key transcription factors and genes identified in this study as potentially mediating these effects, may allow us to substantially improve cognition in adults with and without AD