Distortional Buckling Experiment on Cold-Formed Steel Lipped Channel Columns with Circle Holes under Axial Compression

The objective of this paper is to research the distortional buckling mode and load-carrying capacity of cold-formed thin-walled steel columns with circle holes in web. Compression tests were conducted on 26 intermediate length columns with and without holes. The test members included four different kinds of circle holes. Test results show that the distortional buckling occurred for intermediate columns with holes and the strength of columns with holes was less than that of columns without circle hole. The ultimate strength of columns decreased with the increase of the total transverse width of hole in cross-section of members. For each specimen, a shell finite element Eigen-buckling analysis and nonlinear analysis was also conducted. Analysis results show that the holes can affect on the elastic buckling stress of columns. The shell finite element can be used to model the buckling modes of columns with holes and analyze the load-carrying capacities of members with holes. The comparison on ultimate strength between test results and calculated results using Chinese code GB50018-2002, North American specification AISI S100-2016 and nonlinear Finite Element method was made. The calculated ultimate strength show that results predicted with AISI S100-2016 and analyzed using finite element method are close to test results. The calculated results using Chinese code is higher than test results because Chinese code has no provision to calculate the ultimate strength of members with holes. So the calculated method for cold-formed steel columns with circle holes was proposed. The calculated results using this proposed method show good agreement with test results and can be used in engineering design of cold-formed steel columns with circle hole

Patient safety education for undergraduate medical students: a systematic review

<p>Abstract</p> <p>Background</p> <p>To reduce harm caused by health care is a global priority. Medical students should be able to recognize unsafe conditions, systematically report errors and near misses, investigate and improve such systems with a thorough understanding of human fallibility, and disclose errors to patients. Incorporating the knowledge of how to do this into the medical student curriculum is an urgent necessity. This paper aims to systematically review the literature about patient safety education for undergraduate medical students in terms of its content, teaching strategies, faculty availability and resources provided so as to identify evidence on how to promote patient safety in the curriculum for medical schools. This paper includes a perspective from the faculty of a medical school, a major hospital and an Evidence Based Medicine Centre in Sichuan Province, China.</p> <p>Methods</p> <p>We searched MEDLINE, ERIC, Academic Source Premier(ASP), EMBASE and three Chinese Databases (Chinese Biomedical Literature Database, CBM; China National Knowledge Infrastructure, CNKI; Wangfang Data) from 1980 to Dec. 2009. The pre-specified form of inclusion and exclusion criteria were developed for literature screening. The quality of included studies was assessed using Darcy Reed and Gemma Flores-Mateo criteria. Two reviewers selected the studies, undertook quality assessment, and data extraction independently. Differing opinions were resolved by consensus or with help from the third person.</p> <p>Results</p> <p>This was a descriptive study of a total of seven studies that met the selection criteria. There were no relevant Chinese studies to be included. Only one study included patient safety education in the medical curriculum and the remaining studies integrated patient safety into clinical rotations or medical clerkships. Seven studies were of a pre and post study design, of which there was only one controlled study. There was considerable variation in relation to contents, teaching strategies, faculty knowledge and background in patient safety, other resources and outcome evaluation in these reports. The outcomes from including patient safety in the curriculum as measured by medical students' knowledge, skills, and attitudes varied between the studies.</p> <p>Conclusions</p> <p>There are only a few relevant published studies on the inclusion of patient safety education into the undergraduate curriculum in medical schools either as a selective course, a lecture program, or by being integrated into the existing curriculum even in developed countries with advanced health and education systems. The integration of patient safety education into the existing curriculum in medical schools internationally, provides significant challenges.</p

Analysis of the molecular composition of humic substances and their effects on physiological metabolism in maize based on untargeted metabolomics

IntroductionHumic substances (HSs), components of plant biostimulants, are known to influence plant physiological processes, nutrient uptake and plant growth, thereby increasing crop yield. However, few studies have focused on the impact of HS on overall plant metabolism, and there is still debate over the connection between HS’ structural characteristics and their stimulatory actions.MethodsIn this study, two different HSs (AHA, Aojia humic acid and SHA, Shandong humic acid) screened in a previous experiment were chosen for foliar spraying, and plant samples were collected on the tenth day after spraying (62 days after germination) to investigate the effects of different HSs on photosynthesis, dry matter accumulation, carbon and nitrogen metabolism and overall metabolism in maize leaf.Results and discussionThe results showed different molecular compositions for AHA and SHA and a total of 510 small molecules with significant differences were screened using an ESI-OPLC-MS techno. AHA and SHA exerted different effects on maize growth, with the AHA inducing more effective stimulation than the SHA doing. Untargeted metabolomic analysis revealed that the phospholipid components of maize leaves treated by SHA generally increased significantly than that in the AHA and control treatments. Additionally, both HS-treated maize leaves exhibited different levels of accumulation of trans-zeatin, but SHA treatment significantly decreased the accumulation of zeatin riboside. Compared to CK treatment, AHA treatment resulted in the reorganization of four metabolic pathways: starch and sucrose metabolism, TCA cycle, stilbenes, diarylheptanes, and curcumin biosynthesis, and ABC transport, SHA treatment modified starch and sucrose metabolism and unsaturated fatty acid biosynthesis. These results demonstrate that HSs exert their function through a multifaceted mechanism of action, partially connected to their hormone-like activity but also involving hormoneindependent signaling pathways

Wheat Root Exudates Affected Phosphorus Uptake and Growth of Soybean in Two Farming Systems

Root exudates (REs) of wheat, containing phytosiderophores collected under iron stress conditions were used to assess the phosphorus (P) uptake and growth of soybeans. REs were applied to intercropped and monocultured soybeans. REs of wheat mobilized iron bounded P in an acid soil under monocculture system and increased P uptake of intercropped soybean. Shoot P content of intercropped soybean with REs significantly increased by 165.3% compared to that without REs at the harvest. REs also had a positive effect on shoot biomass of the intercropped soybean. Soil testing indicated that Olsen P may not be a good indicator for plant available P in acid soils

Wheat Root Exudates Affected Phosphorus Uptake and Growth of Soybean in Two Farming Systems

Root exudates (REs) of wheat, containing phytosiderophores collected under iron stress conditions were used to assess the phosphorus (P) uptake and growth of soybeans. REs were applied to intercropped and monocultured soybeans. REs of wheat mobilized iron bounded P in an acid soil under monocculture system and increased P uptake of intercropped soybean. Shoot P content of intercropped soybean with REs significantly increased by 165.3% compared to that without REs at the harvest. REs also had a positive effect on shoot biomass of the intercropped soybean. Soil testing indicated that Olsen P may not be a good indicator for plant available P in acid soils

Analyses of GLONASS and GPS+GLONASS Precise Positioning Performance in Different Latitude Regions

The orbital inclination angle of the GLONASS constellation is about 10° larger than that of GPS, Galileo, and BDS. Theoretically, the higher orbital inclination angle could provide better observation geometry in high latitude regions. A wealth of research has investigated the positioning accuracy of GLONASS and its impact on multi-GNSS, but rarely considered the contribution of the GLONASS constellation’s large orbit inclination angle. The performance of GLONASS in different latitude regions is evaluated in both stand-alone mode and integration with GPS in this paper. The performance of GPS is also presented for comparison. Three international GNSS service (IGS) networks located in high, middle, and low latitudes are selected for the current study. Multi-GNSS data between January 2021 and June 2021 are used for the assessment. The data quality check shows that the GLONASS data integrity is significantly lower than that of GPS. The constellation visibility analysis indicates that GLONASS has a much better elevation distribution than GPS in high latitude regions. Both daily double-difference network solutions and daily static Precise Point Positioning (PPP) solutions are evaluated. The statistical analysis of coordinate estimates indicates that, in high latitude regions, GLONASS has a comparable or even better accuracy than that of GPS, and GPS+GLONASS presents the best estimate accuracy; in middle latitude regions, GPS stand-alone constellation provides the best positioning accuracy; in low latitude regions, GLONASS offers the worst accuracy, but the positioning accuracy of GPS+GLONASS is better than that of GPS. The tropospheric estimates of GLONASS do not present a resemblance regional advantage as coordinate estimates, which is worse than that of GPS in all three networks. The PPP processing with combined GPS and GLONASS observations reduces the convergence time and improves the accuracy of tropospheric estimates in all three networks

In vitro assessment of the effect of four polysaccharides on intestinal bacteria of mice with colitis

Abstract Polysaccharides are typically resistant to digestion in the gastrointestinal tract and are instead degraded by gut microbiota in the colon. As such, they are commonly employed as carriers for colon‐targeted drugs, with the potential to regulate gut microbiota. Pectin, carrageenan, guar gum, and xanthan gum are commonly used polysaccharide carriers, but their degradation in the gut microbiota under colitis conditions as well as their effects on gut microbiota remains unclear. In this study, we performed the in vitro fermentation of these four polysaccharides using colonic content microbiota from mice with colitis and evaluated the degree of polysaccharide degradation and the effects on pH, short‐chain fatty acids, and gut microbiota. Our findings indicate that pectin and guar gum had a greater degree of degradation and promoted the production of butyrate, inhibited the proliferation of harmful bacteria (e.g., Enterobacteriaceae), and increased beneficial bacteria (e.g., Bifidobacterium). In contrast, carrageenan and xanthan gum promote the proliferation of Enterobacteriaceae. These results provide theoretical guidance for the selection of drug delivery carriers for inflammatory bowel disease treatment and provide information on the relationship between polysaccharides and gut microbiota