Effect of Sn Addition on Microstructure, Aging Properties and Softening Resistance of Cu-Cr Alloy.

The relationship between microstructure evolution and properties of a Cu-Cr-Sn alloy during aging and high-temperature softening was investigated in detail in the present work. The results show that the addition of Sn refines obviously the size of the Cr phase and enhances the thermal stability of the alloy, which improves the peak-aged hardness of the Cu-Cr-Sn alloy reaching 139 HV after aging at 450 °C for 240 min. In addition, the recrystallization behavior of the Cu-Cr alloy with the 0.12 wt.% of Sn at high temperature is also significantly inhibited. Lots of precipitated Cr phases and a high density of dislocations are found in the Cu-Cr-Sn alloy annealed at high temperature, resulting in the softening temperature of the Cu-Cr-Sn alloy reaching 565 °C, which is higher than (about 50 °C) that of the Cu-Cr alloy.

Management Algorithm for Prevention of Mother-to-child Transmission of Hepatitis B Virus (2022).

The World Health Organization (WHO) has set the goal of eliminating hepatitis as a threat to public health by 2030. Blocking mother-to-child transmission (MTCT) of hepatitis B virus (HBV) is not only the key to eliminating viral hepatitis, but also a hot issue in the field of hepatitis B prevention and treatment. To standardize the clinical management of preventing MTCT of HBV and achieve zero HBV infection among infants, the Chinese Foundation for Hepatitis Prevention and Control organized experts to compile a management algorithm for prevention of MTCT of HBV based on the latest research progress and guidelines, including 10 steps of pregnancy management and postpartum follow-up, among which screening, antiviral treatment, and infant immunization are its core components.

Management Algorithm for Interrupting Mother-to-Child Transmission of Hepatitis B Virus.

In areas where hepatitis B virus (HBV) is endemic, mother-to-child transmission (MTCT) is the major route of infection of children. Blocking MTCT of HBV therefore would reduce its prevalence. The China Foundation of Hepatitis Prevention and Control organized a team of specialists in infectious diseases, hepatology, immunology, obstetrics, and public health to develop an algorithm for interrupting MTCT of HBV, based on the most recent hepatitis B guidelines and latest evidence. This algorithm comprises 10 steps and has been adopted in clinical practice in China. Four aspects (screening, antiviral intervention during pregnancy, immunoprophylaxis, and postvaccination serologic testing) are the core components of preventing MTCT. Although the combination of passive and active immunization in newborns of hepatitis B surface antigen-positive mothers reduces MTCT of HBV, this immunoprophylaxis cannot completely eradicate MTCT. In the past decade, administration of antiviral agents to pregnant women has been shown to be safe and effective in reducing MTCT of HBV in combination with immunoprophylaxis. Aiming to achieve zero MTCT, this algorithm recommends the use of antivirals during pregnancy by women with high viral loads. Preventing MTCT is key to achieving the goal of eliminating HBV as a public health threat by 2030. Implementation and enhancement of the standardized algorithm for pregnant women with chronic HBV infection and their infants is urgently needed to prevent MTCT.

Wide distribution and genetic diversity of "Candidatus Neoehrlichia mikurensis" in rodents from China.

"Candidatus Neoehrlichia mikurensis" was detected by PCR in 4.0% (34/841) of the rodents tested in this study. The 34 rodents represented nine species from seven regions of China. Phylogenetic analyses based on the partial groEL and nearly entire 16S rRNA gene sequences of the agent revealed genetic diversity, which was correlated with its geographic origins.

Polymorphisms of hypoxia-related genes in subjects susceptible to acute mountain sickness.

BACKGROUND: The occurrence of acute mountain sickness (AMS), which develops in some individuals who ascend to altitudes above 2,500 m, may be associated with 4 hypoxia-related genes (HIF-1, VEGFA, HSP-70 and eNOS). OBJECTIVES: The aim of our study was to investigate the potential role of the 4 hypoxia-related genes in AMS pathogenesis. We therefore evaluated single-nucleotide polymorphisms (SNPs) of the genes in an association study using a case-control design. METHODS: At an altitude of 4,600 m, 64 male Chinese patients with AMS, defined according to the Lake Louise consensus criteria, were compared to 64 Chinese men free of symptoms of AMS. Clinical data, such as age, history of diseases, oxygen saturation (SpO(2)) and heart rate, were obtained. Genotypes of selected SNPs of these genes in patients were compared with those in controls. RESULTS: The mean SpO(2) and heart rate of the AMS and control groups were similar before ascent to high altitude (p = 0.79, p = 0.62) but, 24 h after ascent, the mean SpO(2) of the AMS group was significantly lower than that of the control group (p = 0.001), and the mean heart rate of the AMS group was significantly higher than that of the control group (p = 0.001). Twenty-eight of the 48 SNPs investigated were successfully genotyped, and SNP allele frequencies were obtained. The rs3025039 SNP and the haplotype (rs1413711, rs833070 and rs3025000) in the VEGFA gene were significantly associated with AMS (p = 0.0435 and 0.024, respectively). CONCLUSIONS: Our study demonstrates a possible association between the VEGFA gene and AMS. We conclude that VEGFA may have an important role in the AMS process.

Clinical and immunological characteristics of patients with 2009 pandemic influenza A (H1N1) virus infection after vaccination.

BACKGROUND: We followed a cohort of 773 individuals who received a monovalent vaccine against 2009 pandemic influenza A (H1N1). Approximately 6 weeks after vaccination, 12 persons developed the disease. METHODS: Three groups of subjects were studied (12 patients who had or had not received previous monovalent vaccine and 1 group of 49 control subjects who had previously been immunized with the same vaccine). For all patients, clinical features were characterized and the causative viruses sequenced for possible mutations. Nasopharyngeal swabs, serum specimens, and peripheral blood monocyte cells (PBMCs) were collected at different time points up to 11 weeks after symptom onset to measure the virus load and humoral and cellular immune responses. Serum samples and PBMCs were also collected from 49 and 16 vaccinated control subjects, respectively. RESULTS: Both patient groups had similar clinical manifestations. No substantial viral mutations were detected. Compared with unvaccinated patients, viral loads in vaccinated patients were initially higher, but the levels decreased faster to undetectable levels. However, the virus became detectable again for 6 of them. Two weeks after infection, vaccinated and unvaccinated patients had similar neutralizing antibody levels as the vaccinated control subjects. Thereafter, the neutralizing antibody levels decreased markedly in vaccinated patients. During the acute phase, memory T cell counts and tumor necrosis factor-α levels were significantly higher in vaccinated than in unvaccinated patients. CONCLUSIONS: Although the clinical consequences of infection are comparable between vaccinated and unvaccinated patients, humoral and cellular immune responses in vaccinated patients are boosted for some weeks, indicating an additional benefit of vaccination against 2009 pandemic influenza A (H1N1) virus.

Mixed infections of pandemic H1N1 and seasonal H3N2 viruses in 1 outbreak.

BACKGROUND: In early September 2009, an outbreak of influenza occurred at a college campus in Beijing, China, in which both pandemic H1N1 and seasonal H3N2 viruses were detected. METHODS: Outbreak investigation was performed in the campus. Epidemiologic, clinical data were collected by interviewing patients and retrieving medical records. Individual contact tracing was performed for detailed contact information. Viruses were identified by reverse-transcription polymerase chain reaction assays followed by sequence analysis. The hemagglutination inhibition test was used to detect antibodies to both viruses for paired serum samples. RESULTS: Forty of 45 people with influenza-like illness had laboratory-confirmed influenza A infection; 22 of these 40 people were infected with pandemic H1N1 virus, 12 were infected with seasonal H3N2 virus, and 6 were coinfected with both viruses. In the subsequent generation of cases with mixed infection, we detected pandemic H1N1 virus infection more often than seasonal H3N2 virus infection. The clinical patterns were essentially similar for patients with different virus infections. No substantial differences in sequences were observed in either pandemic H1N1 or seasonal H3N2 virus between patients with mixed and single infection. Sequence analyses revealed that all of the detected viruses were susceptible to oseltamivir but resistant to adamantane. Hemagglutination inhibition tests of paired serum samples confirmed mixed infection in the outbreak. CONCLUSIONS: Cocirculation of pandemic H1N1 virus and seasonal H3N2 virus led to a mixed infection in patients. Pandemic H1N1 virus, however, took prevalence over seasonal influenza virus in the course of transmission. Therefore, competitive circulation of seasonal influenza A virus with the pandemic H1N1 virus seems less likely.