161 research outputs found

    SPRINT STEP-TYPE SPECIFIC CHARACTERISTICS OF ANTHROPOMETRIC AND KINEMATIC VARIABLES IN SPRINTING ACCELERATION

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    The purpose of this study was to compare the anthropometric and the kinematic characteristics during the acceleration phase between stride frequency (SF)-type and stride length (SL)-type sprinters. Seventeen sprinters participated in this study. The maximal 60-m sprints and anthropometric measures were obtained from subjects. Two sprints were recorded by using high-speed cameras. Sprint velocity, SL, SF and their underlying kinematic variables were calculated. Cluster analysis was used to classify the subjects into the SF or SL -type groups (step-type) as indicated by the ratio of the SF and SL at maximum velocity. The SF-type group showed shorter lower limbs length, flight time, lower the height of center of mass at takeoff, smaller swing motion and faster forward rotation of the shank and foot segments than the SL-type group. This study showed the noticeable differences between SFtype and SL-type sprinters were not only in swing motion but also in push-off motion

    TYPE-SPECIFIC STEP CHARACTERISTICS OF SPRINTERS DURING ACCELERATION PHASE OF 100-M RACE

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    The purpose of this study was to show the type-specific step characteristics during acceleration phase (0?30 m) of a 100-m race. Fifty-nine male varsity sprinters (10.68 ± 0.22 s) were recorded running in 100-m races using 10 high-speed cameras, and step variables in 0?30 m and maximum speed phase (MSP, 30?60 m) were calculated. Cluster analysis was used to classify the subjects into the step-frequency (SF) or -length (SL) reliant group (i.e., type-specific) as indicators for the ratio of the SF and SL in the MSP. Then, each group was divided into two sub-groups according to the mean speed in MSP (good and poor sprinters). As a result, the sprinters were classified into SL-, SF-, and Mid-groups. In SL-group, good sprinters showed a longer SL from the 7th step to MSP than the poor sprinters. In SF-group, good sprinters showed a higher SF from the 7th step to MSP than the poor sprinters

    Spectral analysis of an operator associated with linear functional differential equations and its applications

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    The spectral set of an operator which is associated with linear autonomous functional differential equations is determined. The consequence is applied to study the admissibility of linear autonomous functional differential equations for the function space which consists of functions whose spectrum is contained in a fixed closed subset of the real line

    In situ preparation of colloidal iron by microwave irradiation for transmission electron microscopy.

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    We attempted to prepare colloidal iron within tissues by means of microwave irradiation. Mouse tissue blocks were fixed with a mixture of paraformaldehyde and ferric chloride in a cacodylate buffer, immersed in a cacodylate buffered ferric chloride solution, and irradiated in a microwave processor. Colloidal iron was prepared within tissues or cells, and was observed in the form of electron dense fine granules (1-2 nm in diameter) by transmission electron microscopy. Collagen fibrils in the connective tissue showed colloidal iron deposition at regular periodical intervals. Cells in the splenic tissue showed that fine colloidal granules were deposited on the ribosomes but not on the nuclear chromatin. This finding suggests that ferric ions could not diffuse into the nucleus, which was surrounded by the nuclear envelope. The podocyte processes of the renal glomerulus were stained diffusedly. Though this microwave in situ colloidal iron preparation method has some limitations, it is convenient for use in biomedical specimen preparation in transmission electron microscopy.</p

    APC/C-Cdh1-dependent anaphase and telophase progression during mitotic slippage

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    <p>Abstract</p> <p>Background</p> <p>The spindle assembly checkpoint (SAC) inhibits anaphase progression in the presence of insufficient kinetochore-microtubule attachments, but cells can eventually override mitotic arrest by a process known as mitotic slippage or adaptation. This is a problem for cancer chemotherapy using microtubule poisons.</p> <p>Results</p> <p>Here we describe mitotic slippage in yeast <it>bub2Δ </it>mutant cells that are defective in the repression of precocious telophase onset (mitotic exit). Precocious activation of anaphase promoting complex/cyclosome (APC/C)-Cdh1 caused mitotic slippage in the presence of nocodazole, while the SAC was still active. APC/C-Cdh1, but not APC/C-Cdc20, triggered anaphase progression (securin degradation, separase-mediated cohesin cleavage, sister-chromatid separation and chromosome missegregation), in addition to telophase onset (mitotic exit), during mitotic slippage. This demonstrates that an inhibitory system not only of APC/C-Cdc20 but also of APC/C-Cdh1 is critical for accurate chromosome segregation in the presence of insufficient kinetochore-microtubule attachments.</p> <p>Conclusions</p> <p>The sequential activation of APC/C-Cdc20 to APC/C-Cdh1 during mitosis is central to accurate mitosis. Precocious activation of APC/C-Cdh1 in metaphase (pre-anaphase) causes mitotic slippage in SAC-activated cells. For the prevention of mitotic slippage, concomitant inhibition of APC/C-Cdh1 may be effective for tumor therapy with mitotic spindle poisons in humans.</p

    Analysis of complement C4 loci in Caucasoids and Japanese with idiopathic membranous nephropathy

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    Analysis of complement C4 loci in Caucasoids and Japanese with idiopathic membranous nephropathy. Deletion of the HLA class III complement gene, C4A, has been linked with susceptibility to a number of autoimmune diseases. In this study, we show a strong positive association between C4A gene deletion and development of idiopathic membranous nephropathy (IMN) in European Caucasoids [patients, 17/27 (63%); healthy controls, 13/65 (20%); RR 6.8; P = 0.003]. To clarify whether C4A deletion is an independent risk factor for IMN or is increased secondarily to the Caucasoid HLA A1, B8, DR3 extended haplotype, we examined the frequency of C4A deletion in Japanese patients, in whom the disease is associated with another HLA haplotype (DR2-DQw1). Analysis of 31 Japanese patients and 46 healthy controls showed that C4A deletion was present in only one patient (3%) and one control (2%). In addition, examination of the C4B locus in Japanese patients showed that there was no significant increase in the estimated frequency of C4B deletion in patients against controls (31 vs. 27%) and no difference in the frequency of the C4B long gene (73 vs. 87%) or C4B short gene (77 vs. 78%). We conclude that although C4A deletion confers significant risk of IMN in Caucasoids, there is no significant association between C4 polymorphism, as detected here, and risk of IMN in Japanese. This suggests that either C4A deletion is irrelevant to the pathogenesis of IMN or that more than one genetic mechanism is involved

    Dynorphin induced magnetic ordering in lipid bilayers as studied by 31P NMR spectroscopy

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    AbstractLipid bilayers of dimyristoyl phosphatidylcholine (DMPC) containing opioid peptide dynorphin A(1–17) are found to be spontaneously aligned to the applied magnetic field near at the phase transition temperature between the gel and liquid crystalline states (Tm=24°C), as examined by 31P NMR spectroscopy. The specific interaction between the peptide and lipid bilayer leading to this property was also examined by optical microscopy, light scattering, and potassium ion-selective electrode, together with a comparative study on dynorphin A(1–13). A substantial change in the light scattering intensity was noted for DMPC containing dynorphin A(1–17) near at Tm but not for the system containing A(1–13). Besides, reversible change in morphology of bilayer, from small lipid particles to large vesicles, was observed by optical microscope at Tm. These results indicate that lysis and fusion of the lipid bilayers are induced by the presence of dynorphin A(1–17). It turned out that the bilayers are spontaneously aligned to the magnetic field above Tm in parallel with the bilayer surface, because a single 31P NMR signal appeared at the perpendicular position of the 31P chemical shift tensor. In contrast, no such magnetic ordering was noted for DMPC bilayers containing dynorphin A(1–13). It was proved that DMPC bilayer in the presence of dynorphin A(1–17) forms vesicles above Tm, because leakage of potassium ion from the lipid bilayers was observed by potassium ion-selective electrode after adding Triton X-100. It is concluded that DMPC bilayer consists of elongated vesicles with the long axis parallel to the magnetic field, together with the data of microscopic observation of cylindrical shape of the vesicles. Further, the long axis is found to be at least five times longer than the short axis of the elongated vesicles in view of simulated 31P NMR lineshape

    Comparison of Epirubicin-Iodized Oil Suspension and Emulsion for Transcatheter Arterial Chemoembolization in VX2 Tumor

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    To compare the antitumor efficacy and safety of transcatheter arterial chemoembolization (TACE) by epirubicin suspension (epirubicin suspension: epirubicin-iodized oil mixture without solution) to that by epirubicin emulsion (epirubicin emulsion: epirubicin-iodized oil mixture with solution), the efficacy of treatment by administration of either an epirubicin suspension or emulsion was examined in an animal model. Changes in plasma epirubicin concentration were compared over 24 h immediately after treatment, and enhanced ultrasonographic and histopathological analysis subsequently conducted 7 days after treatment to determine the growth ratio and proportion of viable tumor cells. The growth ratio and proportion of viable tumor cells were found to be significantly lower in the suspension group than in the emulsion group while the plasma epirubicin concentration was found to be significantly higher in the suspension group than in the emulsion group. These results indicate that administration of an epirubicin suspension is a superior form of TACE compared to that of administration of an epirubicin emulsion
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