12,182 research outputs found
Optimization of deep drawing process parameters of 304 stainless steel
The one-step drawing process of double-box flume was simulated by finite element method(FEM). It was found that major defects in the forming process were vertical surface fractures in the box and material accumulation near rounded corners. The optimal forming parameters were obtained by optimizing and improving workpiece, single factor analysis and orthogonal experiment optimization. Guiding grooves with an included angle of 140° and a depth of 1 mm was designed in the blank holder to guide materials from accumulation area to insufficient area, thus reducing material fractures and improving deep drawing. The ultimate depth of one-step drawing without defects was increased to 190 mm by optimizing process parameters and improving structure
Comparative study on the broadening of exciton luminescence linewidth due to phonon in zinc-blende and wurtzite GaN epilayers
The broadening of exciton luminescence linewidth due to phonon in zinc-blende and wurtzite GaN epilayers was discussed. The coupling parameters between exciton and acoustic and longitudinal optical phonons were obtained for both structures. The analysis showed that the coupling constants of both exciton-acoustic optial phonon coupling and exciton-longitudinal optical phonon coupling for zinc-blende GaN were almost twice as much as the corresponding values of wurtzite GaN.published_or_final_versio
Direct observation of a Ga adlayer on a GaN(0001) surface by LEED Patterson inversion
A low-energy electron diffraction (LEED) Patterson function (PF) with multiple incident angles is used to obtain three-dimensional interatomic information of hexagonal GaN(0001) grown on a 6H-SiC(0001)-√3 x √3 surface. A Ga-Ga atomic pair between the Ga adlayer and the terminating Ga layer is observed in the LEED PF. This provides direct experimental evidence to support the structural model proposed by first-principles calculations. The LEED PF also shows that the GaN film has a hexagonal structure and the surface has single-bilayer steps.published_or_final_versio
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On the implications of aerosol liquid water and phase separation for modeled organic aerosol mass
Water is an important component of PM2.5 Many traditional SOA species are highly soluble and thus can be considered extractable Water can influence the partitioning of compounds traditionally considered insoluble in models Organic aerosol takes up water according to RH Organic aerosol interacts with inorganic water Deviations in ideality (solubility) must be considered
Valproic Acid Teratogenicity: A Toxicogenomics Approach
Embryonic development is a highly coordinated set of processes that depend on hierarchies of signaling and gene regulatory networks, and the disruption of such networks may underlie many cases of chemically induced birth defects. The antiepileptic drug valproic acid (VPA) is a potent inducer of neural tube defects (NTDs) in human and mouse embryos. As with many other developmental toxicants however, the mechanism of VPA teratogenicity is unknown. Using microarray analysis, we compared the global gene expression responses to VPA in mouse embryos during the critical stages of teratogen action in vivo with those in cultured P19 embryocarcinoma cells in vitro. Among the identified VPA-responsive genes, some have been associated previously with NTDs or VPA effects [vinculin, metallothioneins 1 and 2 (Mt1, Mt2), keratin 1-18 (Krt1-18)], whereas others provide novel putative VPA targets, some of which are associated with processes relevant to neural tube formation and closure [transgelin 2 (Tagln2), thyroid hormone receptor interacting protein 6, galectin-1 (Lgals1), inhibitor of DNA binding 1 (Idb1), fatty acid synthase (Fasn), annexins A5 and A11 (Anxa5, Anxa11)], or with VPA effects or known molecular actions of VPA (Lgals1, Mt1, Mt2, Id1, Fasn, Anxa5, Anxa11, Krt1-18). A subset of genes with a transcriptional response to VPA that is similar in embryos and the cell model can be evaluated as potential biomarkers for VPA-induced teratogenicity that could be exploited directly in P19 cell–based in vitro assays. As several of the identified genes may be activated or repressed through a pathway of histone deacetylase (HDAC) inhibition and specificity protein 1 activation, our data support a role of HDAC as an important molecular target of VPA action in vivo
Assessment of the determinant of choice of ‘over the counter’ analgesics among students of a university in Abbottabad, Pakistan
Purpose: To ascertain the preference of COMSATS Institute of Information Technology, Abbottabad, Pakistan (CIIT) students for various ‘over the counter’ analgesics.Methods: This cross-sectional survey study on self-medication of ibuprofen in students of CIIT was conducted in July - August 2013 using a self-administered questionnaire. Five hundred students with an average age of 20 - 25 years cooperated in this inquisition. The questionnaire contained 18 questions including socio-demographic queries, economical status, perception of the frequency of pain, their locality, and behavior and knowledge of participants on the use of ibuprofen regarding its therapeutic and adverse effects, and interactions.Results: Out of the 500 participants in the study, 70.4 % were female. The response rate was 68.2 %. Ibuprofen (54 %) was the most used analgesic of all the NSAIDs among the respondents. Approximately, 11.2 % of the respondents reported that they suffer from pain almost every day. The younger and more educated respondents had better level of awareness about the ibuprofen’s indications as compared to those who had low level of education. Of the respondents, 29.6 % were not aware of any side effect caused by ibuprofen. Approximately, 22.4 % of the respondents had no knowledge of the interactions of ibuprofen while 61.2 % of the participants consult a physician about painkillers.Conclusion: Although many of the students undergo almost daily pain and favor ibuprofen over other NSAIDs analgesics among but they still lack information on its appropriate handling and safety. The overall result of the survey indicates very low level of information about the drug interaction.Keywords: Pain, OTC, analgesic, ibuprofen, questionnaire based survey, awarenes
Interleukin-1 regulates multiple atherogenic mechanisms in response to fat feeding
Background: Atherosclerosis is an inflammatory process that develops in individuals with known risk factors that include hypertension and hyperlipidaemia, influenced by diet. However, the interplay between diet, inflammatory mechanisms and vascular risk factors requires further research. We hypothesised that interleukin-1 (IL-1) signaling in the vessel wall would raise arterial blood pressure and promote atheroma.
Methodology/Principal Findings: Apoe(-/-) and Apoe(-/-)/IL-1R1(-/-) mice were fed high fat diets for 8 weeks, and their blood pressure and atherosclerosis development measured. Apoe(-/-)/IL-R1(-/-) mice had a reduced blood pressure and significantly less atheroma than Apoe(-/-) mice. Selective loss of IL-1 signaling in the vessel wall by bone marrow transplantation also reduced plaque burden (p<0.05). This was associated with an IL-1 mediated loss of endothelium-dependent relaxation and an increase in vessel wall Nox 4. Inhibition of IL-1 restored endothelium-dependent vasodilatation and reduced levels of arterial oxidative stress.
Conclusions/Significance: The IL-1 cytokine system links atherogenic environmental stimuli with arterial inflammation, oxidative stress, increased blood pressure and atherosclerosis. This is the first demonstration that inhibition of a single cytokine can block the rise in blood pressure in response to an environmental stimulus. IL-1 inhibition may have profound beneficial effects on atherogenesis in man
Developmental changes in the role of different metalinguistic awareness skills in Chinese reading acquisition from preschool to third grade
Copyright @ 2014 Wei et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted
use, distribution, and reproduction in any medium, provided the original author and source are credited.The present study investigated the relationship between Chinese reading skills and metalinguistic awareness skills such as phonological, morphological, and orthographic awareness for 101 Preschool, 94 Grade-1, 98 Grade-2, and 98 Grade-3 children from two primary schools in Mainland China. The aim of the study was to examine how each of these metalinguistic awareness skills would exert their influence on the success of reading in Chinese with age. The results showed that all three metalinguistic awareness skills significantly predicted reading success. It further revealed that orthographic awareness played a dominant role in the early stages of reading acquisition, and its influence decreased with age, while the opposite was true for the contribution of morphological awareness. The results were in stark contrast with studies in English, where phonological awareness is typically shown as the single most potent metalinguistic awareness factor in literacy acquisition. In order to account for the current data, a three-stage model of reading acquisition in Chinese is discussed.National Natural Science Foundation of China and Knowledge Innovation Program of the
Chinese Academy of Sciences
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