562 research outputs found

    A METHOD TO OBTAIN 3D KINEMATICS DATA OF WHOLE HIGH JUMP MOVEMENT

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    The purpose of this study was to introduce how to use 3D image analysis with Pan/Tilt/Zoom cameras to obtain the 3D kinematical data in the event of high jump. The attempts by a chinese elite female highjumper were filmed with two cameras. In addition to control frame, the 3D coordinates of additional control points were measured by a theodolite and transformed into the same reference system. Then these parameters were used in the Motion Analysis System and in the software to level the reference system. Finally, the 3D kinematical data of whole high jump movement could be obtained for further analyzing techniques. This method can be used to analyze other sport events

    Effective Silencing of Sry Gene with RNA Interference in Developing Mouse Embryos Resulted in Feminization of XY Gonad

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    Delivering siRNA or shRNA into the developing embryos is still a main challenge to use of RNAi in mammalian systems. Here we analyze several factors influencing RNAi-mediated silencing of Sry gene, which is a tightly controlled spatiotemporal expressed gene and only shortly expressed in developing mouse embryo gonad. A Sry gene-specific shRNAs expression vector (pSilencer4.1/Sry565) was constructed. The shRNA constructs were mixed with polyethylenimines (PEIs) to form a complex and then injected into pregnant mice though tail vein. Our results showed that Sry gene was downregulated significantly in developing embryos. Further study revealed that knocking-down of Sry expression resulted in feminization of gonad development in mouse embryos and the expression level of Sox9 and Wt1 gene was also significantly changed by downregulation of Sry. The transfection efficiency is associated with the amount of plasmid DNA injection, injection time, injection speed, and volume. Our studies suggest that transplacental RNAi could be implemented by tail vein injection of plasmid vector into pregnant mice

    Research on biomimetic design and impact characteristics of periodic multilayer helical structures

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    Osteons are composed of concentric lamellar structure, the concentric lamellae are composed of periodic thin and thick sub-lamellae, and every 5 sub-lamellae is a cycle, the periodic helix angle of mineralized collagen fibers in two adjacent sub-lamellae is 30°. Four biomimetic models with different fiber helix angles were established and fabricated according to the micro-nano structure of osteon. The effects of the fiber periodic helical structure on impact characteristic and energy dissipation of multi-layer biomimetic composite were investigated. The calculation results indicated that the stress distribution, contact characteristics and fiber failur during impact, and energy dissipation of the composite are affected by the fiber helix angle. The stress concentration of composite materials under external impact can be effectively improved by adjusting the fiber helix angle when the material composition and material performance parameters are same. Compared with the sample30, the maximum stress of sample60 and sample90 increases by 38.1% and 69.8%, respectively. And the fiber failure analysis results shown that the model with a fiber helix angle of 30° has a better resist impact damage. The drop-weight test results shown that the impact damage area of the specimen with 30° helix angle is smallest among the four types of biomimetic specimens. The periodic helical structure of mineralized collagen fibers in osteon can effectively improve the impact resistance of cortical bone. The research results can provide useful guidance for the design and manufacture of high-performance, impact-resistant biomimetic composite materials

    Hamiltonian type Lie bialgebras

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    We first prove that, for any generalized Hamiltonian type Lie algebra LL, the first cohomology group H1(L,LL)H^1(L,L \otimes L) is trivial. We then show that all Lie bialgebra structures on LL are triangular.Comment: LaTeX, 16 page

    Complete mitochondrial genomes of Taenia multiceps, T. hydatigena and T. pisiformis: additional molecular markers for a tapeworm genus of human and animal health significance

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    <p>Abstract</p> <p>Background</p> <p>Mitochondrial genomes provide a rich source of molecular variation of proven and widespread utility in molecular ecology, population genetics and evolutionary biology. The tapeworm genus <it>Taenia </it>includes a diversity of tapeworm parasites of significant human and veterinary importance. Here we add complete sequences of the mt genomes of <it>T. multiceps</it>, <it>T. hydatigena </it>and <it>T. pisiformis</it>, to a data set of 4 published mtDNAs in the same genus. Seven complete mt genomes of <it>Taenia </it>species are used to compare and contrast variation within and between genomes in the genus, to estimate a phylogeny for the genus, and to develop novel molecular markers as part of an extended mitochondrial toolkit.</p> <p>Results</p> <p>The complete circular mtDNAs of <it>T. multiceps</it>, <it>T. hydatigena </it>and <it>T. pisiformis </it>were 13,693, 13,492 and 13,387 bp in size respectively, comprising the usual complement of flatworm genes. Start and stop codons of protein coding genes included those found commonly amongst other platyhelminth mt genomes, but the much rarer initiation codon GTT was inferred for the gene <it>atp</it>6 in <it>T. pisiformis</it>. Phylogenetic analysis of mtDNAs offered novel estimates of the interrelationships of <it>Taenia</it>. Sliding window analyses showed <it>nad</it>6, <it>nad</it>5, <it>atp</it>6, <it>nad</it>3 and <it>nad</it>2 are amongst the most variable of genes per unit length, with the highest peaks in nucleotide diversity found in <it>nad</it>5. New primer pairs capable of amplifying fragments of variable DNA in <it>nad</it>1, <it>rrn</it>S and <it>nad</it>5 genes were designed <it>in silico </it>and tested as possible alternatives to existing mitochondrial markers for <it>Taenia</it>.</p> <p>Conclusions</p> <p>With the availability of complete mtDNAs of 7 <it>Taenia </it>species, we have shown that analysis of amino acids provides a robust estimate of phylogeny for the genus that differs markedly from morphological estimates or those using partial genes; with implications for understanding the evolutionary radiation of important <it>Taenia</it>. Full alignment of the nucleotides of <it>Taenia </it>mtDNAs and sliding window analysis suggests numerous alternative gene regions are likely to capture greater nucleotide variation than those currently pursued as molecular markers. New PCR primers developed from a comparative mitogenomic analysis of <it>Taenia </it>species, extend the use of mitochondrial markers for molecular ecology, population genetics and diagnostics.</p

    Epidemiological and laboratory characteristics of Omicron infection in a general hospital in Guangzhou: a retrospective study

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    The COVID-19 pandemic caused by SARS-CoV-2 has emerged as a major global public health concern. In November 2022, Guangzhou experienced a significant outbreak of Omicron. This study presents detailed epidemiological and laboratory data on Omicron infection in a general hospital in Guangzhou between December 1, 2022, and January 31, 2023. Out of the 55,296 individuals tested, 12,346 were found to be positive for Omicron. The highest prevalence of positive cases was observed in the 20 to 39 age group (24.6%), while the lowest was in children aged 0 to 9 years (1.42%). Females had a higher incidence of infection than males, accounting for 56.6% of cases. The peak time of Omicron infection varied across different populations. The viral load was higher in older adults and children infected with Omicron, indicating age-related differences. Spearman’s rank correlation analysis revealed positive correlations between Ct values and laboratory parameters in hospitalized patients with Omicron infection. These parameters included CRP (rs = 0.059, p = 0.009), PT (rs = 0.057, p = 0.009), INR (rs = 0.055, p = 0.013), AST (rs = 0.067, p = 0.002), LDH (rs = 0.078, p = 0.001), and BNP (rs = 0.063, p = 0.014). However, EO (Eosinophil, rs = −0.118, p &lt; 0.001), BASO (basophil, rs = −0.093, p &lt; 0.001), and LY (lymphocyte, rs = −0.069, p = 0.001) counts showed negative correlations with Ct values. Although statistically significant, the correlation coefficients between Ct values and these laboratory indices were very low. These findings provide valuable insights into the epidemiology of Omicron infection, including variations in Ct values across gender and age groups. However, caution should be exercised when utilizing Ct values in clinical settings for evaluating Omicron infection

    Inhibition of UGT1A1 by natural and synthetic flavonoids

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    Flavonoids are widely distributed phytochemicals in vegetables, fruits and medicinal plants. Recent studies demonstrate that some natural flavonoids are potent inhibitors of the human UDP-glucuronosyltransferase 1A1 (UGT1A1), a key enzyme in detoxification of endogenous harmful compounds such as bilirubin. In this study, the inhibitory effects of 56 natural and synthetic flavonoids on UGT1A1 were assayed, while the structure–inhibition relationships of flavonoids as UGT1A1 inhibitors were investigated. The results demonstrated that the C-3 and C-7 hydroxyl groups on the flavone skeleton would enhance UGT1A1 inhibition, while flavonoid glycosides displayed weaker inhibitory effects than their corresponding aglycones. Further investigation on inhibition kinetics of two strong flavonoid-type UGT1A1 inhibitors, acacetin and kaempferol, yielded interesting results. Both flavonoids were competitive inhibitors against UGT1A1-mediated NHPN-O-glucuronidation, but were mixed and competitive inhibitors toward UGT1A1-mediated NCHN-O-glucuronidation, respectively. Furthermore, docking simulations showed that the binding areas of NHPN, kaempferol and acacetin on UGT1A1 were highly overlapping, and convergence with the binding area of bilirubin within UGT1A1. In summary, detailed structure-inhibition relationships of flavonoids as UGT1A1 inhibitors were investigated carefully and the findings shed new light on the interactions between flavonoids and UGT1A1, and will contribute considerably to the development of flavonoid-type drugs without strong UGT1A1 inhibition.Peer reviewe
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