1,614 research outputs found

    Research on forming quality of poly-wedge pulley spinning

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    As an important power transmission part, pulleys are widely used in automobile industry, agricultural machinery, pumps and machines. A near-net forming process for six-wedge belt pulleys manufacturing was put forward. For this purpose, the required tooth shape and size can be formed directly by spinning without machining. The whole manufacturing procedures include blanking, drawing and spinning. The spinning procedure includes five processes, performing, drumming, thickening, toothing and finishing. The forming defects occurred during each forming processes of poly-wedge pulley spinning, such as the drumming failure, flanged opening-end, folded side-wall, insufficient bottom size, flashed opening-end, cutting-off bottom, are introduced, and the factors influencing the defects are analyzed. The corresponding preventive measures are put forward

    Synthesis of NaYF4:Yb3+, Er3+ upconversion nanoparticles in normal microemulsions

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    An interface-controlled reaction in normal microemulsions (water/ethanol/sodium oleate/oleic acid/n-hexane) was designed to prepare NaYF4:Yb3+, Er3+ upconversion nanoparticles. The phase diagram of the system was first studied to obtain the appropriate oil-in-water microemulsions. Transmission electron microscopy and X-ray powder diffractometer measurements revealed that the as-prepared nanoparticles were spherical, monodisperse with a uniform size of 20 nm, and of cubic phase with good crystallinity. Furthermore, these nanoparticles have good dispersibility in nonpolar organic solvents and exhibit visible upconversion luminescence of orange color under continuous excitation at 980 nm. Then, a thermal treatment for the products was found to enhance the luminescence intensity. In addition, because of its inherent merit in high yielding and being economical, this synthetic method could be utilized for preparation of the UCNPs on a large scale

    Expressions of toll-like receptors 2 and 4, and relative cellular factors in HIV patients with tuberculosis infection

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    Purpose: To investigate the expressions of toll-like receptor 2 (TLR2), toll-like receptor 4 (TLR4), tumor necrosis factor alpha (TNF-α), IFN-γ (IFN- gamma), interleukin 2 (IL-2), interleukin 6 (IL-6) and interleukin 10 (IL-10) in human immunodeficiency virus (HIV) patients with tuberculosis (TB) infection.Methods: Two groups of HIV patients (68 in each group) were used for this study. These were HIV with TB (HIV/TB) group and HIV without TB group. A third group (68 healthy people) served as control. Quantitative polymerase chain reaction (qPCR) was adopted to measure TLR-2 and TLR-4 expressions in peripheral blood mononuclear cells (PBMC), while the serum levels of TNF-α, IFN-γ, IL-2, IL-6 and IL-10 were determined by ELISA.Results: The △Ct values of TLR-2 and TLR-4 in HIV/TB and HIV groups were significantly lower than those in the control group (p < 0.05). Compared to control group, the serum levels of TNF-α, IL-6 and IL-10 significantly increased, while IFN-γ and IL-2 in HIV/TB and HIV groups significantly decreased (p < 0.05). However, IFN-γ and IL-2 decreased significantly in HIV/TB group (p < 0.05). Expression of TLR2 correlated positively with serum levels of TNF-α, IL-6 and IL-10, but negatively with IFN-γ and IL-2 (p < 0.05).Conclusion: TLR2 signal pathway plays a role in HIV patients with TB infection by promoting the expressions of TNF-α, IL-6 and IL-10, while inhibiting IFN-γ and IL-2 cellular factors, and thus may provide a new pathway for the treatment of patients with HIV/TB.Keywords: HIV, Tuberculosis, Toll-like receptor, Cellular factors, Tumor necrosis factor, Interleuki

    Molecular docking studies on rocaglamide, a traditional Chinese medicine for periodontitis

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    Purpose: To undertake an in silico assessment of rocaglamide as a potential drug therapy forperiodontitis (dental arthritis).Method: Lamarckian algorithm-based automated docking approach using AutoDock4.2 tool wasapplied for calculating the best possible binding mode of rocaglamide to IL-23p19 and IL-17, the targets of anti-inflammatory drugs in periodontal disease.Results: The top two interactions of rocaglamide with IL-17 (ΔG = -5.45 and -4.83 kcal/mol) were more spontaneous, and the physical interactions (two hydrogen bonds and one π-πbond) generated in the two IL-17- rocaglamide complexes were higher in number than in IL-23p14-rocaglamide complexes.Conclusion: In silico analysis of rocaglamide, a known antimicrobial and anti-inflammatory agent, is a promising natural candidate for periodontitis therapy, and should be further subjected to in vitro and in vivo anti-periodontitis investigations.Keywords: Periodontitis, Inflammation, Rocaglamide, Molecular docking, Lamarckian algorithm, IL- 23p19, IL-1

    Tetra­aqua­bis­[2-(4-pyridyl­sulfan­yl)acetato-κN]nickel(II)

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    In the centrosymmetric title complex, [Ni(C7H6NO2S)2(H2O)4], the NiII atom, located on a centre of inversion, is coordinated by two N atoms from two 2-(4-pyridyl­sulfan­yl)acetate ligands and four water O atoms in an octa­hedral geometry. In the crystal, inter­molecular O—H⋯O hydrogen bonds between the coordinated water mol­ecules and the carboxyl­ate group of the anionic 2-(4-pyridyl­sulfan­yl)acetate ligands link these discrete mononuclear units into a three-dimensional network

    Prognostic value of vitamin D in patients with pneumonia: A systematic review and meta-analysis

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    Purpose: To investigate the prognostic role of vitamin D in pneumonia patients  through meta-analysis.Methods: PubMed and Embase were systematically searched for relevant studies that assessed the impact of vitamin D on the risk of adverse outcomes among patients with pneumonia. Risk ratios (RR) with 95 % confidence intervals (95 % CI) were pooled using meta-analysis. Q-test and I2 statistics were used to evaluate between-study heterogeneity.Results: Six studies were finally included in the meta-analysis. The results of meta-analysis of these studies indicated that low vitamin D status was associated with higher risk of mortality among pneumonia patients (RR = 2.59, 95 % CI = 1.32-5.08; p = 0.005). Results from meta-analysis of studies with adjusted estimates suggest that low vitamin D status was independently associated with higher risk of mortality among pneumonia patients (RR = 3.15, 95 % CI 1.54-6.44, p = 0.002). There was no significant risk of bias in the meta-analysis.Conclusion: This study demonstrates that low vitamin D level is associated with a higher risk of adverse outcomes in patients with pneumonia.Keywords: Pneumonia, Vitamin D, Prognosis, Meta-analysis, Systematic revie

    Generation of marker- and/or backbone-free transgenic wheat plants via Agrobacterium-mediated transformation

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    Horizontal transfer of antibiotic resistance genes to animals and vertical transfer of herbicide resistance genes to the weedy relatives are perceived as major biosafety concerns in genetically modified (GM) crops. In this study, five novel vectors which used gusA and bar as a reporter gene and a selection marker gene, respectively, were constructed based on the pCLEAN dual binary vector system. Among these vectors, 1G7B and 5G7B carried two T-DNAs located on two respective plasmids with 5G7B possessing an additional virGwt gene. 5LBTG154 and 5TGTB154 carried two T-DNAs in the target plasmid with either one or double right borders, and 5BTG154 carried the selectable marker gene on the backbone outside of the T-DNA left border in the target plasmid. In addition, 5BTG154, 5LBTG154, and 5TGTB154 used pAL154 as a helper plasmid which contains Komari fragment to facilitate transformation. These five dual binary vector combinations were transformed into Agrobacterium strain AGL1 and used to transform durum wheat cv Stewart 63. Evaluation of the co-transformation efficiencies, the frequencies of marker-free transgenic plants, and integration of backbone sequences in the obtained transgenic lines indicated that two vectors (5G7B and 5TGTB154) were more efficient in generating marker-free transgenic wheat plants with no or minimal integration of backbone sequences in the wheat genome. The vector series developed in this study for generation of marker- and/or backbone-free transgenic wheat plants via Agrobacterium-mediated transformation will be useful to facilitate the creation of “clean” GM wheat containing only the foreign genes of agronomic importance

    Single cell epigenomic and transcriptomic analysis uncovers potential transcription factors regulating mitotic/meiotic switch

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    In order to reveal the complex mechanism governing the mitotic/meiotic switch in female germ cells at epigenomic and genomic levels, we examined the chromatin accessibility (scATAC-seq) and the transcriptional dynamics (scRNA-seq) in germ cells of mouse embryonic ovary between E11.5 to 13.5 at single-cell resolution. Adopting a strict transcription factors (TFs) screening framework that makes it easier to understand the single-cell chromatin signature and a TF interaction algorithm that integrates the transcript levels, chromatin accessibility, and motif scores, we identified 14 TFs potentially regulating the mitotic/meiotic switch, including TCFL5, E2F1, E2F2, E2F6, E2F8, BATF3, SP1, FOS, FOXN3, VEZF1, GBX2, CEBPG, JUND, and TFDP1. Focusing on TCFL5, we constructed Tcfl5(+/-) mice which showed significantly reduced fertility and found that decreasing TCFL5 expression in cultured E12.5 ovaries by RNAi impaired meiotic progression from leptotene to zygotene. Bioinformatics analysis of published results of the embryonic germ cell transcriptome and the finding that in these cells central meiotic genes (Stra8, Tcfl5, Sycp3, and E2f2) possess open chromatin status already at the mitotic stage together with other features of TCFL5 (potential capability to interact with core TFs and activate meiotic genes, its progressive activation after preleptotene, binding sites in the promoter region of E2f2 and Sycp3), indicated extensive amplification of transcriptional programs associated to mitotic/meiotic switch with an important contribution of TCFL5. We conclude that the identified TFs, are involved in various stages of the mitotic/meiotic switch in female germ cells, TCFL5 primarily in meiotic progression. Further investigation on these factors might give a significant contribution to unravel the molecular mechanisms of this fundamental process of oogenesis and provide clues about pathologies in women such as primary ovarian insufficiency (POI) due at least in part to meiotic defects
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