Implicit Damping Iterative Algorithm to Solve Elastoplastic Static and Dynamic Equations

This paper presents an implicit damping iterative algorithm to simultaneously solve equilibrium equations, yield function, and plastic flow equations, without requiring an explicit expression of elastoplastic stiffness matrices and local iteration for “return mapping” stresses to the yield surface. In addition, a damping factor is introduced to improve the stiffness matrix conformation in the nonlinear iterative process. The incremental iterative scheme and whole amount iterative scheme are derived to solve the dynamical and static and dynamical elastoplastic problems. To validate the proposed algorithms, computation procedures are designed and the numerical tests are implemented. The computational results verify the correctness and reliability of the proposed implicit iteration algorithms

A Sir2-Like Protein Participates in Mycobacterial NHEJ

In eukaryotic cells, repair of DNA double-strand breaks (DSBs) by the nonhomologous end-joining (NHEJ) pathway is critical for genome stability. In contrast to the complex eukaryotic repair system, bacterial NHEJ apparatus consists of only two proteins, Ku and a multifunctional DNA ligase (LigD), whose functional mechanism has not been fully clarified. We show here for the first time that Sir2 is involved in the mycobacterial NHEJ repair pathway. Here, using tandem affinity purification (TAP) screening, we have identified an NAD-dependent deacetylase in mycobacteria which is a homologue of the eukaryotic Sir2 protein and interacts directly with Ku. Results from an in vitro glutathione S-transferase (GST) pull-down assay suggest that Sir2 interacts directly with LigD. Plasmid-based end-joining assays revealed that the efficiency of DSB repair in a sir2 deletion mutant was reduced 2-fold. Moreover, the Δsir2 strain was about 10-fold more sensitive to ionizing radiation (IR) in the stationary phase than the wild-type. Our results suggest that Sir2 may function closely together with Ku and LigD in the nonhomologous end-joining pathway in mycobacteria

Hypoglycemia and Death in Mice Following Experimental Exposure to an Extract of Trogia venenata Mushrooms

BACKGROUND: Clusters of sudden unexplained death (SUD) in Yunnan Province, China, have been linked to eating Trogia venenata mushrooms. We evaluated the toxic effect of this mushroom on mice. METHODS: We prepared extracts of fresh T. venenata and Laccaria vinaceoavellanea mushrooms collected from the environs of a village that had SUD. We randomly allocated mice into treatment groups and administered mushroom extracts at doses ranging from 500 to 3500 mg/kg and water (control) via a gavage needle. We observed mice for mortality for 7 days after a 3500 mg/kg dose and for 24 hours after doses from 500 to 3000 mg/kg. We determined biochemical markers from serum two hours after a 2000 mg/kg dose. RESULTS: Ten mice fed T. venenata extract (3500 mg/kg) died by five hours whereas all control mice (L. vinaceoavellanea extract and water) survived the seven-day observation period. All mice died by five hours after exposure to single doses of T. venenata extract ranging from 1500 to 3000 mg/kg, while the four mice exposed to a 500 mg/kg dose all survived. Mice fed 2000 mg/kg of T. venenata extract developed profound hypoglycemia (median= 0.66 mmol/L) two hours after exposure. DISCUSSION: Hypoglycemia and death within hours of exposure, a pattern unique among mushroom toxicity, characterize T. venenata poisoning

The Immungenicity and Cross-Neutralizing Activity of Enterovirus 71 Vaccine Candidate Strains

This study aimed to evaluate enterovirus 71 (EV-A71) vaccine candidate strains, including their genotypes, immunogenicity and cross-neutralization capacity. From clinical samples, EV-A71 strains were separated by using Vero cells. Six strains were chosen for vaccine candidates, and the sequences were analyzed. To detect the immunogenicity of the strains, we used them to immunize NIH mice at 0 and 14 days. Cytopathic effects (CPE) were examined to determine the EV-A71 neutralizing antibody (NTAb) titer 14 d after the first and second inoculations. To evaluate the cross-neutralizing capacity of the EV-A71 vaccine candidate strains, we tested serum immunized mice with ten EV-A71 genotype strains. Six EV-A71 vaccine candidate strains were identified, all belonging to sub-genotype C4, the prevalent genotype in China. The sequence similarity of the VP1 regions of the six candidate vaccine strains and three approved inactivated vaccines was 97.58%–97.77%, and the VP1 amino acid similarity was 98.65%–99.33%. Experiments were performed to evaluate the immunogenicity and cross-neutralizing activity of the EV-A71 vaccine candidate strains. The strains had good immunogenicity 14 d after two immunizations, inducing an NTAb titer ranging from 1:94 to 1:346. The NTAb seroconversion rates 14 d after one immunization were above 80% (except HB0007), and significantly increased immunogenicity of EV-A71 strains was observed post-inoculation. Furthermore, our candidate vaccine strains had broad cross-neutralizing activity after challenge with ten sub-genotypes of EV-A71. The highest NTAb titer/lowest NTAb titer ratios of sera against EV-A71 sub-genotypes were 8.0 (JS0002), 8.0 (JS0005), 21.3 (HB0005), 21.3 (HB0007), 10.7 (HB0040) and 8.0 (GD0002), respectively. Our EV-A71 strains had good immunogenicity and cross-neutralization activity, and have the potential to serve as vaccine strains for multivalent hand, foot and mouth disease vaccines

Construction of a cross-species cell landscape at single-cell level.

Individual cells are basic units of life. Despite extensive efforts to characterize the cellular heterogeneity of different organisms, cross-species comparisons of landscape dynamics have not been achieved. Here, we applied single-cell RNA sequencing (scRNA-seq) to map organism-level cell landscapes at multiple life stages for mice, zebrafish and Drosophila. By integrating the comprehensive dataset of > 2.6 million single cells, we constructed a cross-species cell landscape and identified signatures and common pathways that changed throughout the life span. We identified structural inflammation and mitochondrial dysfunction as the most common hallmarks of organism aging, and found that pharmacological activation of mitochondrial metabolism alleviated aging phenotypes in mice. The cross-species cell landscape with other published datasets were stored in an integrated online portal-Cell Landscape. Our work provides a valuable resource for studying lineage development, maturation and aging

Effect of moisture content on compressive and split tensile strength of concrete

427-435The aim of this study is to evaluate the moisture effect on the strength of concrete specimens that has completely cured. This study is also aimed to develop relations that can be used to determine the properties of concrete with different moisture contents that are normally experienced in outside conditions. Numerous compressions and split tensile tests are performed. In order to better understand the results obtained from mechanical tests, a simple empirical formula is suggested that accurately fits experimentally measured sorption data for concrete specimens. Analysis of the collected test results suggests that the moisture content in concrete does have a significant effect on the compressive strength of concrete, but has a much lesser effect on the split tensile strength. As the specimen degrees of saturation increased, the compressive strength fell. However, at nearly saturated condition, an increase in compressive strength can be found

Stress-Strain Behavior of Cementitious Materials with Different Sizes

The size dependence of flexural properties of cement mortar and concrete beams is investigated. Bazant's size effect law and modified size effect law by Kim and Eo give a very good fit to the flexural strength of both cement mortar and concrete. As observed in the test results, a strong size effect in flexural strength is found in cement mortar than in concrete. A modification has been suggested to Li's equation for describing the stress-strain curve of cement mortar and concrete by incorporating two different correction factors, the factors contained in the modified equation being established empirically as a function of specimen size. A comparison of the predictions of this equation with test data generated in this study shows good agreement