282 research outputs found

    High Quality Factor Silicon Cantilever Driven by PZT Actuator for Resonant Based Mass Detection

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    A high quality factor (Q-factor) piezoelectric lead zirconat titanate (PZT) actuated single crystal silicon cantilever was proposed in this paper for resonant based ultra-sensitive mass detection. Energy dissipation from intrinsic mechanical loss of the PZT film was successfully compressed by separating the PZT actuator from resonant structure. Excellent Q-factor, which is several times larger than conventional PZT cantilever, was achieved under both atmospheric pressure and reduced pressures. For a 30 micrometer-wide 100 micrometer-long cantilever, Q-factor was measured as high as 1113 and 7279 under the pressure of 101.2 KPa and 35 Pa, respectively. Moreover, it was found that high-mode vibration can be realized by the cantilever for the pursuit of great Q-factor, while support loss became significant because of the increased vibration amplitude at the actuation point. An optimized structure using node-point actuation was suggested then to suppress corresponding energy dissipation.Comment: Submitted on behalf of EDA Publishing Association (http://irevues.inist.fr/handle/2042/16838

    Structural effects of phosphate groups on apatite formation in a copolymer modified with Ca2+ in a simulated body fluid

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    Organic–inorganic composites are novel bone substitutes that can ameliorate the mismatch of Young\u27s moduli between natural bone and implanted ceramics. Phosphate groups contribute to the formation of apatite in a simulated body fluid (SBF) and the adhesion of osteoblast-like cells. Therefore, modification of a polymer with these functional groups is expected to enhance the ability of the organic–inorganic composite to bond with bone. Two phosphate groups have been used, phosphonic acid (–C–PO3H2) and phosphoric acid (–O–PO3H2). However, the effects of structural differences between these phosphate groups have not been clarified. In this study, the apatite formation of copolymers modified with Ca2+ and either –C–PO3H2 or –O–PO3H2 was examined. The mechanism of apatite formation is discussed based on analytical and computational approaches. The copolymers containing –O–PO3H2, but not those containing –C–PO3H2, formed apatite in the SBF, although both released similar amounts of Ca2+ into the SBF. Adsorption of HPO42− from –O–PO3H2 in the SBF following Ca2+ adsorption was confirmed by zeta-potential measurement and X-ray photoelectron spectroscopy. The measurement of the complex formation constant revealed that the –O–PO32−⋯Ca2+ complex was thermodynamically unstable enough to convert into CaHPO4, which was not the case with –C–PO32−⋯Ca2+. The formation of CaHPO4-based clusters was found to be a key factor for apatite nucleation. In conclusion, this study revealed that modification with –O–PO3H2 was more effective for enhancing apatite formation compared with –C–PO3H2

    A profile of pro-inflammatory cytokine expression in human Delta-1-induced monocyte-derived Langerhans cell-like dendritic cells after stimulation with Toll-like receptor ligands

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    Monocyte-derived Langerhans cell-like dendritic cells (Mo-LCs) are involved in epidermal disorders such as psoriasis in murine models. However, the roles of Mo-LCs in the pathogenesis of psoriasis in humans remain unclear. Also, the contribution of notch ligand delta-like 1 (DLL-1), expressed on keratinocytes, to Mo-LC functions requires clarification. Here, we established a new method of stimulating Mo-LCs derived from CD14+ monocytes with immobilized human DLL-1 to generate induced Mo-LCs (DI(+)Mo-LCs). The DI(+)Mo-LCs were compared to the dendritic cells derived from monocytes (Mo-DCs) cultured with interleukin-4 (IL-4) and granulocyte-macrophage colony-stimulating factor (GM-CSF), and M1 macrophages (Mφ) derived from monocytes cultured with GM-CSF. The DI(+)Mo-LCs were found to produce significant amounts of IL15, IL23A, and interferon-β (IFNB1) in response to the Toll-like receptor (TLR)3 agonist Polyinosinic-polycytidylic acid (Poly(I:C)) or TLR4 agonist lipopolysaccharide (LPS) despite their low expression of tumor necrosis factor (TNF). In conclusion, we have established a new method to generate DI(+)Mo-LCs. We have also discovered that DI(+)Mo-LCs have a unique capacity for producing IL15 and IL23A, which are related to the pathogenesis of psoriasis. Our data contribute to a better understanding of the roles of Mo-LCs in epidermal defense and pathogenesis

    Attenuated Disease in SIV-Infected Macaques Treated with a Monoclonal Antibody against FasL

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    Acute SIVmac infection in macaques is accompanied by high levels of plasma viremia that decline with the appearance of viral immunity and is a model for acute HIV disease in man. Despite specific immune responses, the virus establishes a chronic, persistent infection. The destruction of CD4+ and CD4- lymphocyte subsets in macaques contributes to viral persistence and suggests the importance of mechanisms for depleting both infected and uninfected (bystander) cells. Bystander cell killing can occur when FasL binds the Fas receptor on activated lymphocytes, which include T and B cell subpopulations that are responding to the infection. Destruction of specific immune cells could be an important mechanism for blunting viral immunity and establishing persistent infection with chronic disease. We inhibited the Fas pathway in vivo with a monoclonal antibody against FasL (RNOK203). Here we show that treatment with anti-FasL reduced cell death in circulating T and B cells, increased CTL and antibody responses to viral proteins, and lowered the setpoint viremia. By blocking FasL during only the first few weeks after infection, we attenuated SIVmac disease and increased the life span for infected and treated macaques

    Fabrication of 16-main-core RE123 split wire using inner split method

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    For application to ultrahigh-field nuclear magnetic resonance spectroscopy (e.g., 30 T), we have started to develop a REBa2Cu3O7-δ (RE123, RE: rare earth) multi-core coated conductor in which the ceramic layers (RE123 and buffer layers) are electrically separated to create multiple filaments. This method is called electrical separation by inner splitting, and the wire is called a split wire. The multi-core structure is fabricated using electrical separation by a phase stress, which utilizes the difference in toughness between ceramics and metal, such as partial V-bending by stress along the longitudinal direction of the coated conductor using a commercially available single-core RE123 coated conductor. In addition, about 10 narrow cores (width: 5-15 μm) can be formed by one bending. These cores are called subcores. The wire is composed of main cores and subcores. In this study, a 4 mm wide multifilamentary RE123 split wire with 16 main cores and 150 subcores was fabricated and evaluated. The manufacturing method, microstructure, and critical current properties under an external magnetic field and tension are presented

    ボニュウ エイヨウ ノ モンダイテン

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    Breastfeeding is recognized by many mothers, families and health professionals to beimportant for the health and wellbeing of mothers and babies. One of the important objectivesof the puerperium is to enhance the maternal-infant interaction as regards nutrition ofthe infants. The advantages of breastfeeding are many. Human milk is always at the correcttemperature and requires no sterilization ; the protein content is lower than in formulabut of high quality, gives a small curd, and is easily digestible ; the fats are well absorbed ;the carbohydrate is relatively high in lactose.But there are a few problems in breastfeeding ; for example, 1. breastfeeding jaundice, 2.Vitamin K deficiency, 3. drugs, 4. allergic disease, 5. HTLV-1, 6. The secretion of breast milkin pregnant women after therapy of sterility. We must mange these problems of breastfeeding

    Aluminum Silicate Nanotube Coating of Siloxane-Poly(lactic acid)-Vaterite Composite Fibermats for Bone Regeneration

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    In our earlier work, a flexible fibermat consisting of a biodegradable composite with soluble silicate species, which has been reported to enhance bone formation, was prepared successfully using poly(L-lactic acid) and siloxane-containing calcium carbonate particles by electrospinning. The fibermat showed enhanced bone formation in an in vivo test. In the present work, to improve the hydrophilicity of skeletal fibers in a fibermat, they were coated with nanotubular aluminum silicate crystals, which have a hydrophilic surface that has excellent affinity to body fluids and a high surface area advantageous for pronounced protein adsorption. The nanotubes were coated easily on the fiber surface using an electrophoretic method. In a conventional contact angle test, a drop of water rapidly penetrated into the nanotube-coated fibermat. The culture test using murine osteoblast-like cells (MC3T3-E1) showed that the cell attachment to the nanotube-coated fibermat at an early stage after seeding was enhanced in comparison with that to the noncoated one. This approach may provide a new method of improving the surface of polymer-based biomaterials

    Jet Quenching Parameter in Medium with Chemical Potential from AdS/CFT

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    We calculate the jet quenching parameter in medium with chemical potential from AdS/CFT correspondence. Our result is summarized in a plot. Moreover, we extract the explicit form of the jet quenching parameter of medium with small chemical potential for phases of dual SYM corresponding to large and small black holes. For the former phase, the jet quenching is increased as the charge density increases, however, for the latter it is the opposite though the background is thermodynamically unstable.Comment: 10 pages, 1 figure;v2 minor changes, references added; v3 minor changes and final to PL
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