104 research outputs found

    Parameter identification of nonlinear viscoelastic model with impact area parameter for sport surface by using multi-intensity multi-area impact test

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    AbstractIn previous studies, we proposed various models of material and methods for identifying the parameters of these models by multi-intensity impact test. Especially, the exponential funtion type nonlinear Voigt model shows an excellent accuracy for identifying the property of material behavior. Although other papers show that this model is applicable to the case of varying impact duration and various temperatures, we have not yet discussed how the properties would change as the impact area changed. The purpose of this study is to propose an identification technique of nonlinear Voigt model with hysteresis and dependence on impact area by multi-intensity multi-area impact test. The nonlinear elastic element of this model is expressed by the exponential function based on displacement and impact area. And the nonlinear viscous element of the model is expressed by the product of the exponential function based on displacement and the exponential function based on velocity

    Myocardial sympathetic denervation prevents chamber-specific alteration of beta-adrenergic transmembrane signaling in rabbits with heart failure

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    Objectives.The purpose of this study was to assess the effect of myocardial sympathetic denervation on the chamber-specific alteration of beta-adrenergic signaling in left ventricular failure in rabbits.Background.Local abnormalities in sympathetic nerve terminals, including the neuronal reuptake of norepinephrine, are thought to be responsible for the chamber-specific regulation of beta-adrenergic signaling in heart failure.Methods.Sixteen rabbits were given 6-hydroxydopamine, 25 mg/kg body weight intravenously on days 1 and 2 and 50 mg/kg intravenously on days 7 and 8. Another 16 rabbits received vehicle. Aortic regurgitation was induced in eight of the 6-hydroxydopamine—treated and eight of the vehicle-treated rabbits on day 14. Another eight of the 6-hydroxydopamine—treated and eight of the vehicletreated rabbits underwent a sham operation. The hearts were excised for biochemical analysis on day 21.Results.Hemodynamic characteristics on day 21 showed left ventricular failure in both the aortic regurgitation groups. The plasma norepinephrine concentration on day 21 was higher in both the aortic regurgitation groups than in the sham groups. The beta-adrenoceptor densities and isoproterenol plus 5′guanylylimidodiphosphate-, 5′-guanylylimidodiphosphate- and sodium fluoride-stimulated adenylyl cyclase activities were decreased only in the failing left ventricle of the vehicle-pretreated aortic regurgitation group, but in both ventricles of the 6-hydroxydopamine-pretreated aortic regurgitation group. The basal and forskolin-stimulated adenylyl cyclase activities were similar in both the aortic regurgitation groups and in the sham groups.Conclusions.Sympathetic denervation prevented chamberspecific alterations in beta-adrenergic signaling in acute left ventricular failure. Local loss of sympathetic nerve endings, and especially the defective neuronal norepinephrine reuptake, are likely to be responsible for the chamber-specific alteration of the beta-adrenoceptor-G protein-adenylyl cyclase system in heart failure in rabbits

    Nutrition Support for Head and Neck Squamous Cell Carcinoma Patients Treated with Chemoradiotherapy: How Often and How Long?

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    Background. Oral intake of many patients with locally advanced head and neck cancer (LAHNC) decrease during chemoradiotherapy (CRT). Although prophylactic percutaneous endoscopic gastrostomy (PEG) is recommended, not a few patients complete CRT without using PEG tube. Patients and Methods. The subjects were patients with LAHNC who received CRT. We retrospectively investigated the incidence and duration of nutritional support during and after CRT, and predicting factors of nutritional support. For patients who required nutritional support, we also checked the day of initiation and the duration of nutritional support. Results. Of 53 patients, 29 patients (55%) required nutritional support during and/or after CRT. While no clear relation between requirement of nutritional support and variables including age, T stage, N stage, clinical stage and chemotherapy regimen, there could be some relationships between tumor primary sites and the requirement and duration of nutritional support. 17 (77%) of 22 patients with oropharynx cancer(OP) required nutritional support and prolonged for 4.4 months, and 11 (46%) of 24 patients with hypopharynx cancer(HP) required nutritional support and prolonged for 21.9 months. Conclusion. Nutritional support is indicated many HNC patients treated with CRT and primary sites may have some relation to its indication and duration

    Locality and diel cycling of viral production revealed by a 24 h time course cross-omics analysis in a coastal region of Japan

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    International audienceViruses infecting microorganisms are ubiquitous and abundant in the ocean. However, it is unclear when and where the numerous viral particles we observe in the sea are produced and whether they are active. To address these questions, we performed time-series analyses of viral metagenomes and microbial metatranscriptomes collected over a period of 24 h at a Japanese coastal site. Through mapping the metatranscriptomic reads on three sets of viral genomes ((i) 878 contigs of Osaka Bay viromes (OBV), (ii) 1766 environmental viral genomes from marine viromes, and (iii) 2429 reference viral genomes), we revealed that all the local OBV contigs were transcribed in the host fraction. This indicates that the majority of viral populations detected in viromes are active, and suggests that virions are rapidly diluted as a result of diffusion, currents, and mixing. Our data further revealed a peak of cyanophage gene expression in the afternoon/dusk followed by an increase of genomes from their virions at night and less-coherent infectious patterns for viruses putatively infecting various groups of heterotrophs. This suggests that cyanophages drive the diel release of cyanobacteria-derived organic matter into the environment and viruses of heterotrophic bacteria might have adapted to the population-specific life cycles of hosts

    Cetylpyridinium chloride at sublethal levels increases the susceptibility of rat thymic lymphocytes to oxidative stress

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    Cetylpyridinium chloride (CPC) is an antimicrobial agent used in many personal care products, with subsequent release into the environment. Since CPC is found at low concentrations in river and municipal wastewater, its influence on wildlife is of concern. Therefore, in this study, we used flow cytometry to examine the effects of sublethal concentrations of CPC on rat thymic lymphocytes in order to characterize the cellular actions of CPC at low concentrations in the presence and absence of H2O2-induced oxidative stress. CPC treatment increased the population of living cells with phosphatidylserine exposed on the outer surface of their plasma membranes (a marker of early stage apoptosis), elevated intracellular Zn2+ levels, and decreased the cellular content of nonprotein thiols. CPC also potentiated the cytotoxicity of H2O2. Our results suggest that, even at environmentally relevant sublethal concentrations, CPC exerts cytotoxic effects under oxidative stress conditions by increasing intracellular Zn2+ concentration and decreasing the cellular content of nonprotein thiols. These findings indicate that, under some in vitro conditions, CPC is bioactive at environmentally relevant concentrations. Therefore, CPC release from personal care products into the environment may need to be regulated to avoid its adverse effects on wildlife

    Diffuse Intervertebral Disk Calcification in a Patient with Rheumatoid Arthritis

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    A patient with seronegative rheumatoid arthritis (RA) who presented with intervertebral disk calcification (IDC) of several thoracic and lumbar intervertebral disks is herein described. There was no evidence of any other coexisting diseases such as ochronosis and hemochromatosis, but a remarkable degree of polyclonal hypergammaglobulinemia was observed as a notable finding. Although the appearance of IDC on T1-weighted images on magnetic resonance is controversal, no increased signal intensity was observed in our patient. To the best of our knowledge, this is the first report of IDC in RA

    Defective function of GABA-containing synaptic vesicles in mice lacking the AP-3B clathrin adaptor

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    AP-3 is a member of the adaptor protein (AP) complex family that regulates the vesicular transport of cargo proteins in the secretory and endocytic pathways. There are two isoforms of AP-3: the ubiquitously expressed AP-3A and the neuron-specific AP-3B. Although the physiological role of AP-3A has recently been elucidated, that of AP-3B remains unsolved. To address this question, we generated mice lacking μ3B, a subunit of AP-3B. μ3B−/− mice suffered from spontaneous epileptic seizures. Morphological abnormalities were observed at synapses in these mice. Biochemical studies demonstrated the impairment of γ-aminobutyric acid (GABA) release because of, at least in part, the reduction of vesicular GABA transporter in μ3B−/− mice. This facilitated the induction of long-term potentiation in the hippocampus and the abnormal propagation of neuronal excitability via the temporoammonic pathway. Thus, AP-3B plays a critical role in the normal formation and function of a subset of synaptic vesicles. This work adds a new aspect to the pathogenesis of epilepsy
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