Refugees demonstrate high rates of post-traumatic stress disorder (PTSD) and other psychological disorders. The recent increase in forcible displacement internationally necessitates the understanding ...of factors associated with refugee mental health. While pre-migration trauma is recognized as a key predictor of mental health outcomes in refugees and asylum seekers, research has increasingly focused on the psychological effects of post-migration stressors in the settlement environment. This article reviews the research evidence linking post-migration factors and mental health outcomes in refugees and asylum seekers. Findings indicate that socioeconomic, social, and interpersonal factors, as well as factors relating to the asylum process and immigration policy affect the psychological functioning of refugees. Limitations of the existing literature and future directions for research are discussed, along with implications for treatment and policy.
Dissatisfactory load transfer has been a critical issue in carbon nanotube (CNT)- and graphene-reinforced metal matrix composites (MMCs) mainly because of the intrinsically unpleasant carbon-metal ...interfaces. Here we show by introducing in-situ Al2O3 nanoparticles at aluminum (Al)-CNTs interface, the load transfer efficiency can be noticeably enhanced in powder metallurgy CNTs/Al composites. From in-situ tensile tests, the nanoparticle-modified Al-CNTs interfaces result in CNT fracture, a sign of high load transfer efficiency; while clean interfaces without nanoparticles lead to CNT pulling-out. The nanoparticle-induced enhancement of interface strength can be explained by the increased sliding resistance of CNTs in MMCs at the wake of cracks under tensile loading. Our study provides a new strategy for designing strong carbon-metal interfaces to fabricate high-performance nanocarbon-reinforced MMCs.
Display omitted
•A type of strong Al-CNT interface was studied by TEM and in-situ tensile tests.•Clean Al-CNT interfaces led to CNT pulling-out.•Al-CNT interfaces with in-situ alumina nanoparticles resulted in CNT fracture.•Alumina nanoparticles increased interfacial strength without damaging CNT structure.
A 56‐day feeding trial was carried out to investigate the effect of dietary glutamate (Glu) supplementation on growth performance, digestive enzyme activities and intestinal antioxidant capacity of ...grass carp (Ctenopharyngodon idella). A total of 540 grass carp with average initial weight of 370 ± 3.8 g were fed three diets supplemented with 0, 8 and 16 g kg⁻¹ Glu. The per cent weight gain, specific growth rate, feed conversion ratio, and protein and lipid productive value were significantly improved by dietary Glu supplementation. Feed intake, condition factor, visceral somatic index and perivisceral fat ratio were not significantly different between dietary groups. Hepatosomatic index, intestinal somatic index, intestine length index, intestine protein content, trypsin activity in hepatopancreas and intestine, lipase activity in proximal and mid‐intestine (MI) and hepatopancreas, alkaline phosphatase and gamma‐glutamyl transpeptidase activities in intestine, creatine kinase activities in the mid‐ and distal intestine, intestinal folds height in the proximal and MI were significantly increased with increased Glu. Malondialdehyde and protein carbonyl contents in the intestine decreased with increased Glu. Superoxide anion and hydroxyl radical scavenging ability, glutathione reducase, catalase and total superoxide dismutase activities, and glutathione content in the intestine were increased with increased Glu. These results suggested that dietary Glu supplementation increased intestinal antioxidant capacity, digestive and absorptive ability and improved fish growth.
Ignited by the discovery of the metal-insulator transition, the behaviour of low-disorder two-dimensional (2D) electron systems is currently the focus of a great deal of attention. In the strongly ...interacting limit, electrons are expected to crystallize into a quantum Wigner crystal, but no definitive evidence for this effect has been obtained despite much experimental effort over the years. Here, studying the insulating state of a 2D electron system in silicon, we have found two-threshold voltage-current characteristics with a dramatic increase in noise between the two threshold voltages. This behaviour cannot be described within existing traditional models. On the other hand, it is strikingly similar to that observed for the collective depinning of the vortex lattice in type-II superconductors. Adapting the model used for vortexes to the case of an electron solid yields good agreement with our experimental results, favouring the quantum electron solid as the origin of the low-density state.
Multiferroic films are increasingly being studied for applications in solar energy conversion because of their efficient ferroelectric polarization-driven carrier separation and above-bandgap ...generated photovoltages, which in principle can lead to energy conversion efficiencies beyond the maximum value (34%) reported in traditional silicon-based bipolar heterojunction solar cells. However, the efficiency reported so far is still too low (<2%) to be considered for commercialization. Here, we demonstrate a new approach to effectively tune the bandgap of double perovskite multiferroic oxides by engineering the cationic ordering for the case of Bi sub(2)FeCrO sub(6). Using this approach, we report a power conversion efficiency of 8.1% under AM 1.5G irradiation (100mWcm super(-2)) for Bi sub(2)FeCrO sub(6) thin-film solar cells in a multilayer configuration.
Oxidative stress has a critical role in the pathogenesis of vitiligo. However, the specific molecular mechanism involved in oxidative stress-induced melanocyte death is not well characterized. Given ...the powerful role of microRNAs (miRNAs) in the regulation of cell survival as well as the fact that the generation of miRNAs can be affected by oxidative stress, we hypothesized that miRNAs may participate in vitiligo pathogenesis by modulating the expression of vital genes in melanocytes. In the present study, we initially found that miR-25 was increased in both serum and lesion samples from vitiligo patients, and its serum level was correlated with the activity of vitiligo. Moreover, restoration of miR-25 promoted the H2O2-induced melanocyte destruction and led to the dysfunction of melanocytes. Further experiments proved that MITF, a master regulator in melanocyte survival and function, accounted for the miR-25-caused damaging impact on melanocytes. Notably, other than the direct role on melanocytes, we observed that miR-25 inhibited the production and secretion of SCF and bFGF from keratinocytes, thus impairing their paracrine protective effect on the survival of melanocytes under oxidative stress. At last, we verified that oxidative stress could induce the overexpression of miR-25 in both melanocytes and keratinocytes possibly by demethylating the promoter region of miR-25. Taken together, our study demonstrates that oxidative stress-induced overexpression of miR-25 in vitiligo has a crucial role in promoting the degeneration of melanocytes by not only suppressing MITF in melanocytes but also impairing the paracrine protective effect of keratinocytes. Therefore, it is worthy to investigate the possibility of miR-25 as a potential drug target for anti-oxidative therapy in vitiligo.
SmB6, a well-known Kondo insulator, exhibits a transport anomaly at low temperature. This anomaly is usually attributed to states within the hybridization gap. Recent theoretical work and transport ...measurements suggest that these in-gap states could be ascribed to topological surface states, which would make SmB6 the first realization of topological Kondo insulator. Here by performing angle-resolved photoemission spectroscopy experiments, we directly observe several dispersive states within the hybridization gap of SmB6. These states show negligible kz dependence, which indicates their surface origin. Furthermore, we perform photoemission circular dichroism experiments, which suggest that the in-gap states possess chirality of the orbital angular momentum. These states vanish simultaneously with the hybridization gap at around 150 K. Together, these observations suggest the possible topological origin of the in-gap states.
An adaptive orientation reconstruction algorithm is developed for near‐field high‐energy X‐ray diffraction microscopy. When combined with a spatially adaptive extension the algorithm results in a ...factor of 10–1000 speed‐up over the existing forward modeling reconstruction method while preserving most of the spatial and orientation resolution characteristics. Tests of the reconstruction code based on simulated structures and real data on a complex microstructure are presented. Simulated structures include intra‐granular orientation gradients and noisy detector images. It is shown that resolution in both real space and orientation space degrades gracefully as complexity and detector noise increase.
The study of the relationship between the amount of drug applied to the skin and fraction of drug absorbed can improve our understanding of finite-dose percutaneous absorption in the development of ...topical products and risk assessment of hazardous chemical exposure. It has been previously shown that an increase in the dose applied to the skin leads to a decrease in the fraction of drug permeated the skin (dose-dependent effect). The objective of this research was to examine the dose-dependent effect using permeants of varying physiochemical properties. The dose-dependent effect was studied using human epidermal membrane under finite dose conditions in Franz diffusion cell with model permeants at doses ranging from 0.1 to 200 μg. The dose-dependent effect was evident with model permeants caffeine, corticosterone, dexamethasone, and estradiol, consistent with the relationship of decreasing fraction of dose permeated the skin at increasing the applied dose. However, no significant dose-dependent effect was observed for the polar model permeants urea, mannitol, tetraethyl ammonium, and ethylene glycol, suggesting different transport mechanisms for these permeants. It was also found that, at relatively high doses, estradiol, dexamethasone, and corticosterone could increase the permeation of polar and lipophilic permeants, which could counter the dose-dependent effect under the conditions studied.
•Heat treatment promotes the Ti/C interfacial reaction of the CFs/TC4 composite.•The thickness and structure of the TiC interface are examined.•The 900CFs/TC4 composite shows an excellent ...strength-plasticity match.•Suitable interface TiC thickness and grain size are beneficial for the mechanical performance.
Weak interfacial bonding was a significant problem in titanium matrix composites (TMCs) reinforced with carbon fibers (CFs). In this study, heat treatment (HT) up to 1000 °C was applied on powder metallurgy Ti-6Al-4V matrix composites reinforced with discontinuous CFs to obtain different interfacial structures. Mechanical tests at both room-temperature and 500 °C showed that the best mechanical properties were attained at HT temperature of 900 °C. To understand the underlying mechanism, the phase structure, grain morphology and interfacial microstructure were examined. It was found that as HT temperature was increased, the interface thickness increases continuously and obvious grain growth happens at 1000 °C. Suitable interfacial reaction and fine grain size are identified as critical structural parameters to obtain high-performance CFs/TMCs. This study may provide new insight into the role of interfacial structure played in the strengthening effect of CFs/TMCs.
PDF
