508 research outputs found

    Observation of Plasma Hole in an ECR Ar Plasma

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    The first experimental observation of a plasma hole structure in an ECR argon plasma is reported. The plasma hole is a cylindrical density cavity, which is formed spontaneously in the center of the plasma. The steep density gradient between the hole plasma and the ambient plasma is sustained by a thin interfacial layer, the width of which is a few ion Larmor radii. Supersonic rotation is found over the large cross-sectional area of Ar plasma hole. The axial flow can also exceed ion sound speed. Spectral measurements revealed that the neutral density profile exhibits a hole structure as well as that in ion density, the diameter of which is much shorter than the mean free path of neutral particles

    THE INITIAL CONDITIONS AT RELEASE IN HAMMER THROW OF WORLD CLASS TOP ATHLETES

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    INTRODUCTION: In hammer throw, the influence of the air resistance is negligibly smaller in comparison with javelin and discus throw. Therefore, the throwing distance of a projectile object is practically determined by the initial conditions at release such as initial velocity, the angle of projection and the release height. The purpose of this study was to investigate the influence of initial conditions at release on the throwing distance of hammer throw

    Development of fully-automated synthesis systems

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    This paper describes the development of fully-automated synthesis systems for preparing and isolating various kinds of pharmaceutical compounds. The systems are versatile, and are able to perform most of the chemical reactions currently used in organic chemistry, with the exception of hydrogenation which requires high pressure. An additional benefit is the very user-friendly software

    INFLUENCE OF BODY WEIGHT ON PULLING FORCE IN HAMMER THROW

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    In hammer throw it can be considered that the body weight affects the throwing distance because the muscle volume is directly proportional to the body weight. The pulling force of the hammer may also be affected by the body weight. The purpose of this study was to investigate the influence of the body weight on the pulling force during throwing motion in hammer throw

    Biexciton binding energy in CuCl quantum dots

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    Induced absorption from the exciton state to the biexciton state was clearly observed under the site-selective excitation of the inhomogeneously broadened Z3 exciton band in CuCl microcrystallites embedded in NaCl crystals. This allows us to obtain the size-dependent biexciton binding energy in CuCl quantum dots. The binding energy of biexcitons increases with the decrease in their size and its size dependence and bulk value are well represented by the expression 78/a*2+52/a*+33 (meV), where a* is the effective radius of microcrystallites in a unit of nm. The experimental results are compared with an available theoretical result. The enhanced Coulomb interaction in microcrystallites still increases the biexciton binding energy in the large-size regime, where the quantum confinement energy of excitons is not considerable. The size-dependent biexciton binding energy cannot be explained by the weak-confinement model of biexcitons

    Evolutionally Conserved Function of Kisspeptin Neuronal System Is Nonreproductive Regulation as Revealed by Nonmammalian Study

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    The kisspeptin neuronal system, which consists of a neuropeptide kisspeptin and its receptor Gpr54, is considered in mammals a key factor of reproductive regulation, the so-called hypothalamic–pituitary–gonadal (HPG) axis. However, in nonmammalian vertebrates, especially in teleosts, existence of kisspeptin regulation on the HPG axis is still controversial. In this study, we applied multidisciplinary techniques to a teleost fish, medaka, and examined possible kisspeptin regulation on the HPG axis. First, we generated knockout medaka for kisspeptin-related genes and found that they show normal fertility, gonadal maturation, and expression of gonadotropins. Moreover, the firing activity of GnRH1 neurons recorded by the patch clamp technique was not altered by kisspeptin application. Furthermore, in goldfish, in vivo kisspeptin administration did not show any positive effect on HPG axis regulation. However, as kisspeptin genes are completely conserved among vertebrates except birds, we surmised that kisspeptin should have some important nonreproductive functions in vertebrates. Therefore, to discover novel functions of kisspeptin, we generated a gpr54-1:enhanced green fluorescent protein (EGFP) transgenic medaka, whose gpr54-1–expressing cells are specifically labeled by EGFP. Analysis of neuronal projection of gpr54-1:EGFP–expressing neurons showed that these neurons in the ventrolateral preoptic area project to the pituitary and are probably involved in endocrine regulation other than gonadotropin release. Furthermore, combination of deep sequencing, histological, and electrophysiological analyses revealed various novel neural systems that are under control of kisspeptin neurons—that is, those expressing neuropeptide Yb, cholecystokinin, isotocin, vasotocin, and neuropeptide B. Thus, our new strategy to genetically label receptor-expressing neurons gives insights into various kisspeptin-dependent neuronal systems that may be conserved in vertebrates

    Helping-Like Behaviour in Mice Towards Conspecifics Constrained Inside Tubes

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    Prosocial behaviour, including helping behaviour, benefits others. Recently, helping-like behaviour has been observed in rats, but whether it is oriented towards rescue, social contact with others, or other goals remains unclear. Therefore, we investigated whether helping-like behaviour could be observed in mice similar to that in rats. Because mice are social animals widely used in neuroscience, the discovery of helping-like behaviour in mice would be valuable in clarifying the psychological and biological mechanisms underlying pro-sociability. We constrained mice inside tubes. Subject mice were allowed to move freely in cages with tubes containing constrained conspecifics. The subject mice released both cagemates and stranger mice but did not engage in opening empty tubes. Furthermore, the same behaviour was observed under aversive conditions and with anesthetised conspecifics. Interestingly, hungry mice opened the tubes containing food before engaging in tube-opening behaviour to free constrained conspecifics. Mice showed equal preferences for constrained and freely moving conspecifics. We demonstrated for the first time that mice show tube-opening behaviour. Furthermore, we partly clarified the purpose and motivation of this behaviour. An effective mouse model for helping-like behaviour would facilitate research on the mechanisms underlying prosocial behaviour

    Twin Rectal Tonsils Mimicking Carcinoid or Mucosa-Associated Lymphoid Tissue Lymphoma

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    The rectal tonsil is a rare polypoid lesion exclusively found in the rectum and is considered a reactive proliferation of the lymphoid tissue. Although this lesion is benign, we recommend that it should be differentiated from carcinoid or polypoid type of mucosa-associated lymphoid tissue lymphomas, based on gross findings. In this case report, we describe a case of rectal lesions with a unique appearance in a 41-year-old man. Colonoscopy revealed two 5-mm-sized nodules located opposite from each other on the left and right sides of the lower rectum. Endoscopic mucosal resection was conducted. Histopathologically, both lesions were mainly located in the submucosa and consisted of prominent lymphoid follicles with germinal centers of various sizes. No immunoreactivity of Bcl-2 was seen in the germinal centers. Immunohistochemical staining for kappa and lambda light chains revealed a polyclonal pattern. Therefore, these lesions were diagnosed as rectal tonsils

    Layer-specific expression of extracellular matrix molecules in the mouse somatosensory and piriform cortices

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    In the developing central nervous system (CNS), extracellular matrix (ECM) molecules have regulating roles such as in brain development, neural-circuit maturation, and synaptic-function control. However, excluding the perineuronal net (PNN) area, the distribution, constituent elements, and expression level of granular ECM molecules (diffuse ECM) present in the mature CNS remain unclear. Diffuse ECM molecules in the CNS share the components of PNNs and are likely functional. As cortical functions are greatly region-dependent, we hypothesized that ECM molecules would differ in distribution, expression level, and components in a region- and layer-dependent manner. We examined the layer-specific expression of several chondroitin sulfate proteoglycans (aggrecan, neurocan, and brevican), tenascin-R, Wisteria floribunda agglutinin (WFA)-positive molecules, hyaluronic acid, and link protein in the somatosensory and piriform cortices of mature mice. Furthermore, we investigated expression changes in WFA-positive molecules due to aging. In the somatosensory cortex, PNN density was particularly high at layer 4 (L4), but not all diffuse ECM molecules were highly expressed at L4 compared to the other layers. There was almost no change in tenascin-R and hyaluronic acid in any somatosensory-cortex layer. Neurocan showed high expression in L1 of the somatosensory cortex. In the piriform cortex, many ECM molecules showed higher expression in L1 than in the other layers. However, hyaluronic acid showed high expression in deep layers. Here, we clarified that ECM molecules differ in constituent elements and expression in a region- and layer-dependent manner. Region-specific expression of ECM molecules is possibly related to functions such as region-specific plasticity and vulnerability
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