AbstractExperimental research on seismic behavior of structural columns is one of the most important and active research areas in structural engineering. Various methods with innovative loading ...configurations have been developed by researchers over the past several decades, and the research has enhanced our knowledge about the performance of structural columns, resulting in the improvement of design practice. This paper provides a state-of-the-art review of the testing setups for simulating earthquake loading on structural columns, to reveal the trend of sophistication of testing methods. Special attention is given to the large tonnage axial loading methods and the shortcomings of existing methods. Based on past experiences and a review of existing methods, a new multiuse structural testing (MUST) system is developed and described in this paper. Because the MUST equipment has the unique ability to maintain the axial load vertical during lateral loading, and the force inputs to the structural model can be directly measured, it is more suitable for simulating structural responses under horizontal and vertical ground motions.
Summary
Background
Tinea capitis is still common in developing countries, such as China. Its pathogen spectrum varies across regions and changes over time.
Objectives
This study aimed to clarify the ...current epidemiological characteristics and pathogen spectrum of tinea capitis in China.
Methods
A multicentre, prospective descriptive study involving 29 tertiary hospitals in China was conducted. From August 2019 to July 2020, 611 patients with tinea capitis were enrolled. Data concerning demography, risk factors and fungal tests were collected. When necessary, the pathogens were further identified by morphology or molecular sequencing in the central laboratory.
Results
Among all enrolled patients, 74·1% of the cases were in patients aged 2–8 years. The children with tinea capitis were mainly boys (56·2%) and were more likely than adults to have a history of animal contact (57·4% vs. 35·3%, P = 0·012) and zoophilic dermatophyte infection (73·5% vs. 47%). The adults were mainly female (83%) and were more likely than children to have anthropophilic agent infection (53% vs. 23·9%). The most common pathogen was zoophilic Microsporum canis (354, 65·2%), followed by anthropophilic Trichophyton violaceum (74, 13·6%). In contrast to the eastern, western and northeastern regions, where zoophilic M. canis predominated, anthropophilic T. violaceum predominated in central China (69%, P < 0·001), where the patients had the most tinea at other sites (20%) and dermatophytosis contact (26%) but the least animal contact (39%). Microsporum ferrugineum was the most common anthropophilic agent in the western area, especially in Xinjiang province.
Conclusions
Boys aged approximately 5 years were the most commonly affected group. Dermatologists are advised to pay more attention to the different transmission routes and pathogen spectra in different age groups from different regions.
What is already known about this topic?
Tinea capitis is an infection of the scalp and hair caused by dermatophytes and is still common in developing countries. Prepubertal children are mainly affected.
The pathogen spectrum of tinea capitis varies across different geographical areas and changes over time.
Nationwide prospective epidemiological surveys of tinea capitis in China are rare and out of date.
What does this study add?
This study provides data concerning the epidemiological characteristics and pathogen spectrum of tinea capitis in contemporary China.
Boys aged approximately 5 years were most commonly affected and were more likely than adults to have zoophilic dermatophyte infection.
The main pathogens of tinea capitis in China are zoophilic dermatophytes, mainly Microsporum canis. In contrast to the other regions, the predominant pathogens in central China are anthropophilic dermatophytes.
Plain language summary available online
Influenza A virus (IAV) infection leads to variable and imperfectly understood pathogenicity. We report that segment 3 of the virus contains a second open reading frame ("X-ORF"), accessed via ...ribosomal frameshifting. The frameshift product, termed PA-X, comprises the endonuclease domain of the viral PA protein with a C-terminal domain encoded by the X-ORF and functions to repress cellular gene expression. PA-X also modulates IAV virulence in a mouse infection model, acting to decrease pathogenicity. Loss of PA-X expression leads to changes in the kinetics of the global host response, which notably includes increases in inflammatory, apoptotic, and T lymphocyte-signaling pathways. Thus, we have identified a previously unknown IAV protein that modulates the host response to infection, a finding with important implications for understanding IAV pathogenesis.
Intestinal IgA, which is regulated by gut microbiota, has a crucial role in maintenance of intestinal homeostasis and in protecting the intestines from inflammation. However, the means by which ...microbiota promotes intestinal IgA responses remain unclear. Emerging evidence suggests that the host can sense gut bacterial metabolites in addition to pathogen-associated molecular patterns and that recognition of these small molecules influences host immune response in the intestines and beyond. We reported here that microbiota metabolite short-chain fatty acid acetate promoted intestinal IgA responses, which was mediated by "metabolite-sensing" GPR43. GPR43
mice demonstrated lower levels of intestinal IgA and IgA
gut bacteria compared with those in wild type (WT) mice. Feeding WT but not GPR43
mice acetate but not butyrate promoted intestinal IgA response independent of T cells. Acetate promoted B-cell IgA class switching and IgA production in vitro in the presence of WT but not GPR43
dendritic cells (DCs). Mechanistically, acetate-induced DC expression of Aldh1a2, which converts Vitamin A into its metabolite retinoic acid (RA). Moreover, blockade of RA signaling inhibited the acetate induction of B-cell IgA production. Our studies thus identified a new pathway by which microbiota promotes intestinal IgA response through its metabolites.
Stress is an external event or condition that places a strain on a biological system. The animal response to a stress involves the expenditure of energy to remove or reduce the impact of the stress. ...This increases maintenance requirements of the animal and results in loss of production. The biological response to stress is divided into acute and chronic phases, with the acute phase lasting hours to a few days and the chronic phase lasting several days to weeks. The acute response is driven by homeostatic regulators of the nervous and endocrine systems and the chronic phase by homeorhetic regulators of the endocrine system. Both responses involve alterations in energy balance and metabolism. Thermal environment affects all animals and therefore represents the largest single stressor in animal production. Other types of stressors include housing conditions, overcrowding, social rank, disease, and toxic compounds. “Acclimation” to a stress is a phenotypic response developed by the animal to an individual stressor within the environment. However, under natural conditions, it is rare for only one environmental variable to change over time. “Acclimatization” is the process by which an animal adapts to several stressors within its natural environment. Acclimation is a homeorhetic process that takes several weeks to occur and occurs via homeorhetic, not homeostatic, mechanisms. It is a phenotypic change that disappears when the stress is removed. When the stress is severe and not relieved by acclimatization or management changes, the animal is considered chronically stressed and is susceptible to increased incidence of disease and poor health. Milk yield and reproduction are extremely sensitive to stress because of the high energy and protein demands of lactation and the complexity of the reproductive process and multiple organs that are involved. Improvements in protection of animals against stress require improved education of producers to recognize stress and methods for estimating degree of stress on animals.
Water plays an important role in the whole process of geopolymer synthesis. X-ray diffraction (XRD) and thermogravimetry (TG) showed that residual water depressed the activity development of calcined ...kaolin before stable crystalline phases formed as confirmed by the compressive strength. Reaction heat evolution measurement revealed that high liquid/solid ratio could accelerate the dissolution of raw materials and the hydrolysis of Si
4+ and Al
3+ compounds but hinder the polycondensation when OH
− concentration is high enough as 12 mol/L. The effect of nonevaporable water on the strength variation of geopolymers was firstly analyzed. The results indicated that nonevaporable water was necessary to keep the strength stable and the optimum content was about 7.4%.
•Developed a new type of hybrid space truss system composed of steel lower chord and glubam upper chords and web elements.•Experimentally investigated the gravity loading behavior of the steel-glubam ...truss, validating its good capacity.•Different possible failure modes were investigated and the lower chord yielding can offer larger deformability.
This paper introduces a new type of hybrid truss system composed of glue laminated bamboo (glubam) for web and upper chord members and steel pipes for lower chords. Several experiments of physical and mechanical properties were carried out on the glubam material for structural design and construction according to timber specifications and codes. A full-scale space truss model with different configurations was constructed and tested under gravity loads. Different failure modes, such as buckling of web chords, shear fracture of bolted connecting joints and yield of bottom steel pipes, were discussed. Analyses of the structural behavior under static load are compared with the experimental results, showing a good agreement. The experimental results validate that the space truss system is of excellent load carrying capacity. If yielding of the lower chord steel pipes can be realized, the system can also have a large plastic deformation under the ultimate loading condition. A prototype structure was successfully designed and constructed as a rain-shed canopy of an office building.
► Numerical typhoon wind-field model applied to southeast China costal regions is validated. ► Probabilistic models for key typhoon parameters in this region are established. ► Extreme wind speeds ...for 11 cities in this regions is predicted by simulating 1000
years of typhoons. ► The resulted wind speeds agree reasonably well with those in available literature.
Southeast coastal region is the most developed and populated area in China, and also is one of the regions most seriously impacted by typhoons in the world. In this paper, typhoon wind hazard analysis for 11 major cities, Shanghai, Ningbo, Wenzhou, Fuzhou, Xiamen, Taipei, Guangzhou, Shenzhen, Hong Kong, Zhanjiang, and Haikou, in the southeast China coastal regions, is conducted for the first time. The historical typhoon data from the China Meteorological Administration (CMA) and the State Oceanic Administration is carefully processed and the probabilistic distributions of the key typhoon parameters for the 11 cities are established. The correlations between the key typhoon parameters are carefully evaluated. The wind field model given by Thompson and Cardone is introduced, and the radial pressure profile is properly addressed with validation of the model by six cyclones. Monte Carlo random sampling method is employed to generate virtual typhoons and 1000
years of typhoons are simulated for the 11 cities. Extreme wind speeds of different return periods are then predicted. There is a reasonable agreement between the predictions of wind speed in the code of Hong Kong and available literature, suggesting that the approach is effective in determining the design wind speeds for critical structures in the southeast China coastal regions.
In recent years, recovery of metals from electronic waste within the European Union has become increasingly important due to potential supply risk of strategic raw material and environmental ...concerns. Electronic waste, especially a mixture of end-of-life electronic products from a variety of sources, is of inherently high complexity in composition, phase, and physiochemical properties. In this research, a closed-loop hydrometallurgical process was developed to recover valuable metals, i.e., copper and precious metals, from an industrially processed information and communication technology waste. A two-stage leaching design of this process was adopted in order to selectively extract copper and enrich precious metals. It was found that the recovery efficiency and extraction selectivity of copper both reached more than 95% by using ammonia-based leaching solutions. A new electrodeposition process has been proven feasible with 90% current efficiency during copper recovery, and the copper purity can reach 99.8 wt %. The residue from the first-stage leaching was screened into coarse and fine fractions. The coarse fraction was returned to be releached for further copper recovery. The fine fraction was treated in the second-stage leaching using sulfuric acid to further concentrate precious metals, which could achieve a 100% increase in their concentrations in the residue with negligible loss into the leaching solution. By a combination of different leaching steps and proper physical separation of light materials, this process can achieve closed-loop recycling of the waste with significant efficiency.
PDF
