1,143 research outputs found

    Inscribing or Circumscribing a Histogon to a Convex Polygon

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    We consider two optimization problems of approximating a convex polygon, one by a largest inscribed histogon and the other by a smallest circumscribed histogon. An axis-aligned histogon is an axis-aligned rectilinear polygon such that every horizontal edge has an integer length. A histogon of orientation ? is a copy of an axis-aligned histogon rotated by ? in counterclockwise direction. The goal is to find a largest inscribed histogon and a smallest circumscribed histogon over all orientations in [0,?). Depending on whether the horizontal width of a histogon is predetermined or not, we consider several different versions of the problem and present exact algorithms. These optimization problems belong to shape analysis, classification, and simplification, and they have applications in various cost-optimization problems

    Bone regeneration potential of sub-microfibrous membranes with osteogenic induction of rBMSC for tissue engineering

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    Purpose: To examine the biocompatibility and osteoinductive potential of  sub-microfibrous membranes with cells in vitro and in vivo.Methods: Polylactic acid (PLA) and poly-ε-caprolactone (PCL) were blended at various volume ratios (PLA:PCL = 100:0, 70:30, 50:50, 30:70 and 0:100) and each membrane form was prepared by electrospinning. Cell viability,  biocompatibility, and bone regeneration were measured.Results: The membranes from the PLA/PCL blends prepared by an electrospinning process showed a range of diameter distribution ranging from 1,580 to 550 nm. The cells of 100 % PCL membrane (smallest diameter) exhibited significantly higher adhesion and proliferation than those of the other membranes. Among the  membranes from PLA/PCL blends, PCL membrane showed weak inflammatory changes in the early stages of implantation without acute or chronic inflammation. PCL membranes with osteogenically-induced cells successfully stimulated new bone formation in a rate calvarial defect model.Conclusion: The results indicate that biodegradable PCL sub-microfibrous membrane produced by electrospinning process seems to have excellent biocompatibility, and may be used as a scaffold for bone tissue engineering.Keywords: Biocompatibility, Hard tissue, Biomaterial availability, Bone remodeling, Polylactic acid, Poly-ε-caprolactone, Osteoinductive potential, Sub-microfibrous membrane

    A Three-Step Resolution-Reconfigurable Hazardous Multi-Gas Sensor Interface for Wireless Air-Quality Monitoring Applications

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    This paper presents a resolution-reconfigurable wide-range resistive sensor readout interface for wireless multi-gas monitoring applications that displays results on a smartphone. Three types of sensing resolutions were selected to minimize processing power consumption, and a dual-mode front-end structure was proposed to support the detection of a variety of hazardous gases with wide range of characteristic resistance. The readout integrated circuit (ROIC) was fabricated in a 0.18 ??m CMOS process to provide three reconfigurable data conversions that correspond to a low-power resistance-to-digital converter (RDC), a 12-bit successive approximation register (SAR) analog-to-digital converter (ADC), and a 16-bit delta-sigma modulator. For functional feasibility, a wireless sensor system prototype that included in-house microelectromechanical (MEMS) sensing devices and commercial device products was manufactured and experimentally verified to detect a variety of hazardous gases

    The farnesoid X receptor negatively regulates osteoclastogenesis in bone remodeling and pathological bone loss

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    Farnesoid X receptor (FXR, NR1H4) is a member of the nuclear receptor superfamily of ligand-activated transcription factors. Since the role of FXR in osteoclast differentiation remains ill-defined, we investigated the biological function of FXR on osteoclastogenesis, using FXR-deficient mice. We demonstrated that FXR deficiency increases osteoclast formation in vitro and in vivo. First, FXR deficiency was found to accelerate osteoclast formation via down-regulation of c-Jun N-terminal kinase (JNK) 1/2 expression. Increased expression of peroxisome proliferator-activated receptor (PPAR)γ and peroxisome proliferator-activated receptor gamma coactivator 1 (PGC- 1)β seems to mediate the pro-osteoclastogenic effect of FXR deficiency via the JNK pathway. In addition, we found that FXR deficiency downregulated the expression of interferon-β (IFN-β), a strong inhibitor of osteoclastogenesis, via receptor activator of nuclear factor-kappaB ligand (RANKL). We further suggested that interference of IFN-β expression by FXR deficiency impaired the downstream JAK3-STAT1 signaling pathways, which in turn increased osteoclast formation. Finally, FXR deficiency accelerated unloading- or ovariectomy-induced bone loss in vivo. Thus, our findings demonstrate that FXR is a negative modulator in osteoclast differentiation and identify FXR as a potential therapeutic target for postmenopausal osteoporosis and unloadinginduced bone loss

    Photodistributed Telangiectasia Induced by Amlodipine

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    Calcium channel blockers are widely used antihypertensive drugs, which are uncommonly associated with cutaneous reactions, such as pruritus, urticaria, or alopecia. Photosensitivity presenting with telangiectasia has rarely been described. We present here a case of photodistributed telangiectasia induced clinically by amlodipine and histologically by enlarged capillaries in the upper dermis without signs of vasculitis

    MRI Findings of Pericardial Fat Necrosis: Case Report

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    Pericardial fat necrosis is an infrequent cause of acute chest pain and this can mimic acute myocardial infarction and acute pericarditis. We describe here a patient with the magnetic resonance imaging (MRI) findings of pericardial fat necrosis and this was correlated with the computed tomography (CT) findings. The MRI findings may be helpful for distinguishing pericardial fat necrosis from other causes of acute chest pain and from the fat-containing tumors in the cardiophrenic space of the anterior mediastinum

    A Case of Cicatricial Alopecia Associated with Erlotinib

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    Erlotinib is a small-molecule tyrosine kinase inhibitor (TKI) of the epidermal growth factor receptor (EGFR). Erlotinib has been used primarily to treat non-small cell lung cancer. In addition to its role in tumor cells, EGFR is also an important regulator of growth and differentiation in the skin and hair. Therefore, EGFR-TKIs have been associated with a number of cutaneous side effects including follicular acneiform eruptions, cutaneous xerosis, chronic paronychia, desquamation, seborrheic dermatitis, and hair texture changes. Herein, we report a rare case of a 61-year-old woman who was treated with erlotinib and experienced cicatricial alopecia
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