Search

The effect of spheroidizing annealing on carbide characteristic parameters, mechanical properties and wear resistance of the quenching and tempering (Q&T) high carbon martensitic stainless steel is investigated. The microstructure of the steel is characterized and analyzed through various techniques, including scanning electron microscope (SEM), X‐ray diffraction (XRD), electron backscattering diffraction (EBSD), and transmission electron microscope (TEM). Results show that the microstructure of the annealing steel is mainly composed of ferrite and M23C6 carbide. With the rise of austenitizing temperature, the average diameter of carbide of the annealed steel increases. The average diameter of carbides in the Q&T steel changes in the same way as that observed in the annealed steel. The steel has the lowest annealing hardness, highest Q&T toughness, and wear resistance at an annealed soaking temperature of 860 °C. The influence factor of the toughness and wear resistance can be identified that small‐sized carbides and low angle grain boundaries exhibit strong interface adhesive strength. This reduces the probability of cracking in the particle or at the interface. [ABSTRACT FROM AUTHOR]

Plastic food contact materials (FCM)-based products were widely used in everyday life. These products were normally imposed to strict regulations in order to pass the enforcement tests of compliance as a prefix condition. However, even in these “qualified” materials, unknown chemical substances, not involving in legislation lists, could migrate from FCM. In this perspective, the present work aims to thoroughly analyze by means of Gas Chromatography-Mass Spectrometry (GC-MS) the different substances/migrants in 120 qualified FCM plastic products. Unexpectedly, among the identified compounds (nearly 100), only 13% was included in the permitted list of Commission Regulation EU No 10/2011. All the identified compounds were classified into 11 categories according to their chemical structure and the FCM type, whereas toxicology data were in addition analyzed. Each plastic type exhibited different preferences of chemical migrants. Fortunately, most of the compounds identified were of low toxicity, and only 4 chemicals were included in priority lists and previous literature reports as potential risk factors. Subsequently, the accurate amount of these 4 chemicals was determined. The amount of Bis(2-ethylhexyl) adipate (DEHA) and Bis(2-ethylhexyl) phthalate (DEHP) were lower than the SML in Commission Regulation EU No 10/2011, and that of stearamide was under the recommended use quantity. The 2,4-di-tert-butylphenol (2,4-DTBP) was widely exist in the investigated FCM products. Among them, the highest level is obtained in polypropylene/low density polyethylene (BOPP/LDPE) materials, up to 45.568±31.513 mg/kg. In summary, a panel of unlisted chemical migrants were discovered and identified by GS-MS screening. The results implied that plastic FCMs were not so “inert” as they usually considered, and further safety evaluation should be performed toward the complete identification of new substances in FCM products. [ABSTRACT FROM AUTHOR]

Abstract: MicroRNAs regulate gene expression at the post-transcriptional level and were involved in diverse biological and pathological processes. Single nucleotide polymorphism (SNP) which is located in the pre-miRNA may affect the processing and then influence the expression of mature miRNA. Previous studies yielded conflicting results as to the association of a common polymorphism in pre-miRNAs (i.e. hsa-miR-499 rs3746444) with various diseases. Therefore, here we performed a meta-analysis to address the association between this polymorphism and cancer risks. A total of twenty studies involving 10,584 cases and 12,414 controls were retrieved based on PubMed. No significant association was found either in cancers and other diseases in all genetic models. And then in the stratified analysis by ethnicity, significantly increased risks were found in Asians (OR=1.11; 95% CI=1.00–1.23 for C vs. T; OR=1.16; 95% CI=1.00–1.36 for TC vs. TT; OR=1.15; 95%CI=1.01–1.31 for TC/CC vs. TT), but not in Caucasians in all comparison models tested. Our meta-analysis suggested that polymorphism of hsa-miR-499 rs3746444 T>C was not associated with the increased susceptibility to cancers and other diseases. [Copyright &y& Elsevier]

Reverse genetics systems have been established for all major groups of plant DNA and positive-strand RNA viruses, and our understanding of their infection cycles and pathogenesis has benefitted enormously from use of these approaches. However, technical difficulties have heretofore hampered applications of reverse genetics to plant negative-strand RNA (NSR) viruses. Here, we report recovery of infectious virus from cloned cDNAs of a model plant NSR, Sonchus yellow net rhabdovirus (SYNV). The procedure involves Agrobacterium-mediated transcription of full-length SYNV antigenomic RNA and co-expression of the nucleoprotein (N), phosphoprotein (P), large polymerase core proteins and viral suppressors of RNA silencing in Nicotiana benthamiana plants. Optimization of core protein expression resulted in up to 26% recombinant SYNV (rSYNV) infections of agroinfiltrated plants. A reporter virus, rSYNV-GFP, engineered by inserting a green fluorescence protein (GFP) gene between the N and P genes was able to express GFP during systemic infections and after repeated plant-to-plant mechanical passages. Deletion analyses with rSYNV-GFP demonstrated that SYNV cell-to-cell movement requires the sc4 protein and suggested that uncoiled nucleocapsids are infectious movement entities. Deletion analyses also showed that the glycoprotein is not required for systemic infection, although the glycoprotein mutant was defective in virion morphogenesis. Taken together, we have developed a robust reverse genetics system for SYNV that provides key insights into morphogenesis and movement of an enveloped plant virus. Our study also provides a template for developing analogous systems for reverse genetic analysis of other plant NSR viruses. [ABSTRACT FROM AUTHOR]

Background: Hand, foot and mouth disease (HFMD) is caused by a variety of enterovirus serotypes and the etiological spectrum worldwide has changed since a large scale of outbreaks occurred in 1997. Methods: A large number of clinical specimens of HFMD patients were collected in Xiangyang and genotyping was performed by qRT-PCR, conventional PCR amplification and sequencing. Among the 146 CV-A5 detected cases, the complete genome sequences of representative strains were determined for genotyping and for recombination analysis. Results: It was found that CV-A5 was one of the six major serotypes that caused the epidemic from October 2016 to December 2017. Phylogenetic analyses based on the VP1 sequences showed that these CV-A5 belonged to the genotype D which dominantly circulated in China. Recombination occurred between the CV-A5 and CV-A2 strains with a breakpoint in the 2A region at the nucleotide 3791. Conclusions: The result may explain the emergence of CV-A5 as one of the major pathogens of HFMD. A multivalent vaccine against HFMD is urgently needed to control the disease and to prevent emerging and spreading of new recombinants. [ABSTRACT FROM AUTHOR]

In China, incidences involving pupils suffering health problems caused by synthetic running tracks have attracted the public's attention. However, the existence of known and unknown harmful chemicals in the tracks have not yet been explored. Here, the levels of 16 known harmful ingredients were firstly analyzed in 167 school running tracks. In all samples, the recognized toxic solvents and additives, such as the benzene series, soluble mercury, 3,3′-dichloro-4,4′-diaminodiphenylmethane (MOCA) and toluene diisocyanate monomer (TDI) were under the limits of detection. In contrast, polycyclic aromatic hydrocarbons (PAHs), phthalates, Short chain chlorinated paraffins (SCCPs) soluble lead, cadmium and chromium were found in 86%, 88%, 46%, 81%, 43% and 83% of the specimens, respectively. The levels, toxicology and distribution of these known chemicals were evaluated. Then, a static-headspace gas chromatography-mass spectrometer (GC-MS) method in full scan mode was employed to screen for unknown volatile chemicals. Three groups of chemicals reflecting different kinds of pollution sources were discovered: new solvents, such as N, N-Dimethylformamide, new additives, such as 2-ethylhexanoic acid, and by-products, such as carbon disulfide. In summary, the existence of potential risk factors in school plastic tracks was revealed through exhaustive testing. Moreover, most of the hazardous components detected have been recently included in a new national standard to improve the safety performance of synthetic running tracks. [ABSTRACT FROM AUTHOR]

This study described the spatial distribution and trend of HIV/AIDS among older adults in China, and we tried to identify the clustering of infections and translocation of hotspots during the study period.Background. Recent studies have indicated an increasing burden of human immunodeficiency virus (HIV)/AIDS among older adults.Methods. All identified people living with HIV/AIDS (PLWHA) recorded through the Chinese HIV/AIDS CRS during 2005–2012 were included in the study, except for the cases that lacked specific spatial information. Trend tests and spatial analyses were conducted.Results. Information about 73,521 PLWHA (aged ≥50 years) was collected during 2005–2012. Three provinces—Guangxi, Henan, and Yunnan—accounted for 54.4% of the identified cases during the study period. Compared with 2005, the ratio between residents and migrants among the study population decreased to 40.1% in 2012. The ratio of HIV-infected patients to AIDS patients and the ratio of males to females increased gradually among older infected adults. Results of spatial analysis indicate a clustered distribution of HIV/AIDS among older adults throughout the country. Hot spots were observed in 4 provinces (Guangxi, Henan, Yunnan, and Sichuan) and 1 municipality (Chongqing). A trend from central provinces toward southern provinces was also identified.Conclusions. The number and proportion of HIV/AIDS among older adults have increased in recent years. The hot spots showed movement from central to southern China. A focused intervention strategy targeting the older PLWHA is urgently required in China. [ABSTRACT FROM AUTHOR]

This study described the prevalence and trend of HIV, hepatitis C virus (HCV) and syphilis among female sex workers (FSWs) in China, and we tried to identify the correlation between HIV, HCV and syphilis. Disparity of the epidemics were found between lower-tier and higher-tier FSWs.Background. Studies on the transmission of human immunodeficiency virus (HIV) and sexually transmitted diseases in female sex workers (FSWs) have been limited primarily to inferences drawn by focusing on defined geographical areas.Methods and Findings. This serial cross-sectional study was conducted in mainland China from 2008 through 2012. Data for 827 079 participants was analyzed. We classified venues such as karaoke bars and hotels as high tier and venues such as hair salons and barbershops, massage parlors, and other public outdoor venues as low tier based on the participants’ socioeconomic status. FSWs who worked at the venues and those who were present on the days of the survey were recruited.The prevalence of HIV decreased from 0.6% in 2008 to 0.3% in 2012, the syphilis prevalence ranged from 2.4% to 3.2% between 2008 and 2012, and hepatitis C virus (HCV) prevalence decreased from 0.9% in 2008 to 0.8% in 2012. Further, we found that HIV, syphilis, and HCV prevalence proportions were high in FSWs from low tiers.Conclusions. HIV, syphilis, and HCV prevalence among FSWs in our study decreased during the study period. Comprehensive intervention strategies, particularly those that focus on low-tier and older FSWs, are needed in order to decrease the disease burden in this population. [ABSTRACT FROM AUTHOR]