522 research outputs found

    Reaction Behavior of a Silicide Electrode with Lithium in an Ionic-Liquid Electrolyte

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    Silicides are attractive novel active materials for use in the negative-electrodes of next-generation lithium-ion batteries that use certain ionic-liquid electrolytes; however, the reaction mechanism of the above combination is yet to be clarified. Possible reactions at the silicide electrode are as follows: deposition and dissolution of Li metal on the electrode, lithiation and delithiation of Si, which would result from the phase separation of the silicide, and alloying and dealloying of the silicide with Li. Herein, we examined these possibilities using various analysis methods. The results revealed that the lithiation and delithiation of silicide occurred

    Electrochemical Lithiation and Delithiation Properties of FeSi2/Si Composite Electrodes in Ionic-Liquid Electrolytes

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    We investigated the applicability of ionic-liquid electrolytes to FeSi2/Si composite electrode for lithium-ion batteries. In conventional organic-liquid electrolytes, a discharge capacity of the electrode rapidly faded. In contrast, the electrode exhibited a superior cycle life with a reversible capacity of 1000 mA h g(Si)−1 over 850 cycles in a certain ionic-liquid electrolyte. The difference in the cycle life was explained by surface film properties. In addition, the rate performance of the FeSi2/Si electrode improved in another ionic-liquid electrolyte. Remarkably, lithiation of only Si in FeSi2/Si composite electrode occurred whereas each FeSi2- and Si-alone electrode alloyed with Li in the ionic-liquid electrolyte. FeSi2 certainly covered the shortcomings of Si and the FeSi2/Si composite electrode exhibited improved cycle life and rate capability compared to Si-alone electrode

    Joint Degradation in a Monkey Model of Collagen-Induced Arthritis: Role of Cathepsin K Based on Biochemical Markers and Histological Evaluation

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    The role of cathepsin K in joint degradation in a model of collagen-induced arthritis (CIA) in cynomolgus monkey was examined using biochemical markers and histology. Joint swelling, urinary C-telopeptide of type II collagen (CTX-II), deoxypyridinoline (DPD), and N- and C-telopeptides of type I collagen (NTX and CTX-I, resp.) were analyzed. Immunohistochemistry of type II collagen, cathepsin K, and CTX-II were performed using joints. Joint swelling reached peak on day 42 and continued at this level. The CTX-II level peaked on day 28 and declined thereafter, while CTX-I, NTX, and DPD reached plateau on day 43. Joint swelling was positively correlated with CTX-II increases on days 20 and 42/43, with increases in CTX-I and NTX/Cr on days 42/43 and 84, and with DPD increases throughout the study period. Intense cathepsin K staining was observed in osteoclasts and in articular cartilage and synovial tissue in arthritic joints. CTX-II was present in the superficial layer of articular cartilage in CIA monkeys. Evidence from biochemical markers suggests that matrix degradation in the CIA model starts with degradation of cartilage, rather than bone resorption. Cathepsin K expressed in osteoclasts, articular cartilage, and synovial tissue may contribute to degradation of cartilage

    Two New Tryptamine Derivatives, Leptoclinidamide and (-)-Leptoclinidamine B, from an Indonesian Ascidian Leptoclinides dubius

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    Two new tryptamine-derived alkaloids, named as leptoclinidamide (1) and (-)-leptoclinidamine B (2), were isolated from an Indonesian ascidian Leptoclinides dubius together with C2-α-D-mannosylpyranosyl-L-tryptophan (3). The structure of 1 was assigned on the basis of spectroscopic data for 1 and its N-acetyl derivative (4). Compound 1 was an amide of tryptamine with two β-alanine units. Although the planar structure of 2 is identical to that of the known compound (+)-leptoclinidamine B (5), compound 2 was determined to be the enantiomer of 5 based on amino acid analysis using HPLC methods. Compounds 1 to 4 were evaluated for cytotoxicity against two human cancer cell lines, HCT-15 (colon) and Jurkat (T-cell lymphoma) cells, but none of the compounds showed activity

    Eccentric Figure-Eight Coils for Transcranial Magnetic Stimulation

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    Previously we proposed an eccentric figure-eight coil that can cause threshold stimulation in the brain at lower driving currents. In this study, we performed numerical simulations and magnetic stimulations to healthy subjects for evaluating the advantages of the eccentric coil. The simulations were performed using a simplified spherical brain model and a realistic human brain model. We found that the eccentric coil required a driving current intensity of approximately 18% less than that required by the concentric coil to cause comparable eddy current densities within the brain. The eddy current localization of the eccentric coil was slightly higher than that of the concentric coil. A prototype eccentric coil was designed and fabricated. Instead of winding a wire around a bobbin, we cut eccentric-spiral slits on the insulator cases, and a wire was woven through the slits. The coils were used to deliver magnetic stimulation to healthy subjects; among our results, we found that the current slew rate corresponding to motor threshold values for the concentric and eccentric coils were 86 and 78 A/µs, respectively. The results indicate that the eccentric coil consistently requires a lower driving current to reach the motor threshold than the concentric coil. Future development of compact magnetic stimulators will enable the treatment of some intractable neurological diseases at home. Bioelectromagnetics. 35:55–65, 2015. © 2014 Wiley Periodicals, Inc.ArticleBIOELECTROMAGNETICS. 36(1):55-65 (2015)journal articl

    Development of a Gastric Cancer Diagnostic Support System with a Pattern Recognition Method Using a Hyperspectral Camera

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    Gastric cancer is a completely curable cancer when it can be detected at its early stage. Thus, because early detection of gastric cancer is important, cancer screening by gastroscopy is performed. Recently, the hyperspectral camera (HSC), which can observe gastric cancer at a variety of wavelengths, has received attention as a gastroscope. HSC permits the discerning of the slight color variations of gastric cancer, and we considered its applicability to a gastric cancer diagnostic support system. In this paper, after correcting reflectance to absorb the individual variations in the reflectance of the HSC, a gastric cancer diagnostic support system was designed using the corrected reflectance. In system design, the problems of selecting the optimum wavelength and optimizing the cutoff value of a classifier are solved as a pattern recognition problem by the use of training samples alone. Using the hold-out method with 104 cases of gastric cancer as samples, design and evaluation of the system were independently repeated 30 times. After analyzing the performance in 30 trials, the mean sensitivity was 72.2% and the mean specificity was 98.8%. The results showed that the proposed system was effective in supporting gastric cancer screening

    Secular trends and features of thalamic hemorrhages compared with other hypertensive intracerebral hemorrhages: an 18-year single-center retrospective assessment

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    IntroductionTrends regarding the locations of hypertensive cerebral hemorrhages are unclear. To clarify hypertensive hemorrhage trends, we investigated intracerebral hemorrhages (ICHs) over an 18-year period, focusing on thalamic hemorrhages compared with other sites of hemorrhages.MethodsWe reviewed the cases of patients hospitalized for hypertensive ICH in 2004–2021 at our hospital; 1,320 eligible patients were registered with a primary ICH/intraventricular hemorrhage. After exclusion criteria were applied, we retrospectively analyzed 1,026 hypertensive ICH cases.ResultsThe proportions of thalamic and subcortical hemorrhages increased over the 18-year period, whereas putaminal hemorrhage decreased. Multivariate logistic regression analyses revealed that for thalamic hemorrhage, ≥200 mmHg systolic blood pressure (p = 0.031), bleeding <15 mL (p = 0.001), and higher modified Rankin scale (mRS) score ≥ 4 at discharge (p = 0.006) were significant variables in the late period (2013–2021) versus the early period (2004–2012), whereas for putaminal hemorrhage, significant factors in the late period were triglyceride <150 mg/dL (p = 0.006) and mRS score ≥ 4 at discharge (p = 0.002). Among the features of the thalamic hemorrhages in the late period revealed by our group comparison with the putaminal and subcortical hemorrhages, the total and subcortical microbleeds were more notable in the thalamic hemorrhages than in the other two types of hemorrhage, whereas cerebellar microbleeds were more prominent when compared only with subcortical hemorrhages.DiscussionOur findings revealed an increasing trend for thalamic hypertensive hemorrhage and a decreasing trend for putaminal hemorrhage. The thalamic hemorrhage increase was observed in both young and older patients, regardless of gender. The main features of thalamic hemorrhage in the late period versus the early period were decrease in larger hemorrhage (≥15 mL) and an increase in cases with higher systolic blood pressure (at least partially involved a small number of untreated hypertensive patients who developed major bleeding). The total and subcortical microbleeds were more notable in the thalamic hemorrhages of the late period than in the putaminal and subcortical hemorrhages. These results may contribute to a better understanding of the recent trends of hypertensive ICHs and may help guide their appropriate treatments for this condition

    Gene expression profile and pathogenicity of biofilm-forming Prevotella intermedia strain 17

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    <p>Abstract</p> <p>Background</p> <p><it>Prevotella intermedia </it>(<it>P. intermedia</it>), a gram-negative, black-pigmented anaerobic rod, has been implicated in the development of chronic oral infection. <it>P. intermedia </it>strain 17 was isolated from a chronic periodontitis lesion in our laboratory and described as a viscous material producing strain. The stock cultures of this strain still maintain the ability to produce large amounts of viscous materials in the spent culture media and form biofilm-like structures. Chemical analyses of this viscous material showed that they were mainly composed of neutral sugars with mannose constituting 83% of the polysaccharides. To examine the biological effect of the extracellular viscous materials, we identified and obtained a naturally-occurring variant strain that lacked the ability to produce viscous materials <it>in vitro </it>from our stock culture collections of strain 17, designated as 17-2. We compared these two strains (strains 17 versus 17-2) in terms of their capacities to form biofilms and to induce abscess formation in mice as an indication of their pathogenicity. Further, gene expression profiles between these two strains in planktonic condition and gene expression patterns of strain 17 in solid and liquid cultures were also compared using microarray assays.</p> <p>Results</p> <p>Strain 17 induced greater abscess formation in mice as compared to that of the variant. Strain 17, but not 17-2 showed an ability to interfere with the phagocytic activity of human neutrophils. Expression of several genes which including those for heat shock proteins (DnaJ, DnaK, ClpB, GroEL and GroES) were up-regulated two to four-fold with statistical significance in biofilm-forming strain 17 as compared to the variant strain 17-2. Strain 17 in solid culture condition exhibited more than eight-fold up-regulated expression levels of several genes which including those for levanase, extracytoplasmic function-subfamily sigma factor (σ<sup>E</sup>; putative) and polysialic acid transport protein (KpsD), as compared to those of strain 17 in liquid culture media.</p> <p>Conclusion</p> <p>These results demonstrate that the capacity to form biofilm in <it>P. intermedia </it>contribute to their resistance against host innate defence responses.</p
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