1,218 research outputs found

    Analytical Studies on a Modified Nagel-Schreckenberg Model with the Fukui-Ishibashi Acceleration Rule

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    We propose and study a one-dimensional traffic flow cellular automaton model of high-speed vehicles with the Fukui-Ishibashi-type (FI) acceleration rule for all cars, and the Nagel-Schreckenberg-type (NS) stochastic delay mechanism. By using the car-oriented mean field theory, we obtain analytically the fundamental diagrams of the average speed and vehicle flux depending on the vehicle density and stochastic delay probability. Our theoretical results, which may contribute to the exact analytical theory of the NS model, are in excellent agreement with numerical simulations.Comment: 3 pages previous; now 4 pages 2 eps figure

    Design of Novel S-Shaped Quad-Band Antenna for MedRadio/WMTS/ISM Implantable Biotelemetry Applications

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    A novel S-shaped quad-band planar inverted-F antenna (PIFA) is proposed for implantable biotelemetry in the Medical Device Radiocommunications Service (MedRadio) band (401–406 MHz), Wireless Medical Telemetry Service (WMTS) band (1427–1432 MHz), and industrial, scientific, and medical (ISM) bands (433-434 MHz and 2.4–2.4835 GHz). The proposed antenna reveals compact dimension of 254 mm3 (10×10×2.45 mm3) and is composed of three substrates and a superstrate, which are constructed from an S-shaped radiator (layer 1) and two twin radiators of spiral structures (layer 2 and layer 3). The optimal antenna characteristics were measured in the ground pork skin, and the measured bandwidths are 150 MHz for the MedRadio and ISM bands (433 MHz), 52 MHz for the WMTS band, and 102 MHz for the ISM band (2.4 GHz), respectively. The characteristics of proposed antenna are enough to support the applications of implantable body area networks (BAN) for biotelemetry and can completely cover main available frequency bands of BAN for biotelemetry below 3 GHz

    Synergistic effect of phosphodiesterase 4 inhibitor and serum on migration of endotoxin-stimulated macrophages.

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    Macrophage migration is an essential step in host defense against infection and wound healing. Elevation of cAMP by inhibiting phosphodiesterase 4 (PDE4), enzymes that specifically degrade cAMP, is known to suppress various inflammatory responses in activated macrophages, but the role of PDE4 in macrophage migration is poorly understood. Here we show that the migration of Raw 264.7 macrophages stimulated with LPS was markedly and dose-dependently induced by the PDE4 inhibitor rolipram as assessed by scratch wound healing assay. Additionally, this response required the involvement of serum in the culture medium as serum starvation abrogated the effect. Further analysis revealed that rolipram and serum exhibited synergistic effect on the migration, and the influence of serum was independent of PDE4 mRNA expression in LPS-stimulated macrophages. Moreover, the enhanced migration by rolipram was mediated by activating cAMP/exchange proteins directly activated by cAMP (Epac) signaling, presumably via interaction with LPS/TLR4 signaling with the participation of unknown serum components. These results suggest that PDE4 inhibitors, together with serum components, may serve as positive regulators of macrophage recruitment for more efficient pathogen clearance and wound repair

    Experimental and Numerical Analysis of High-Resolution Injection Technique for Capillary Electrophoresis Microchip

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    This study presents an experimental and numerical investigation on the use of high-resolution injection techniques to deliver sample plugs within a capillary electrophoresis (CE) microchip. The CE microfluidic device was integrated into a U-shaped injection system and an expansion chamber located at the inlet of the separation channel, which can miniize the sample leakage effect and deliver a high-quality sample plug into the separation channel so that the detection performance of the device is enhanced. The proposed 45° U-shaped injection system was investigated using a sample of Rhodamine B dye. Meanwhile, the analysis of the current CE microfluidic chip was studied by considering the separation of Hae III digested ϕx-174 DNA samples. The experimental and numerical results indicate that the included 45° U-shaped injector completely eliminates the sample leakage and an expansion separation channel with an expansion ratio of 2.5 delivers a sample plug with a perfect detection shape and highest concentration intensity, hence enabling an optimal injection and separation performance

    Starch granules as Pickering emulsifiers: role of octenylsuccinylation and particle size

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    The present study aimed at investigating the effects of octenylsuccinylation and particle size on the emulsifying properties of starch granules as Pickering emulsifiers. Starch spherulites (1-5 μm), native rice starch (5-10 μm), waxy maize starch (10-20 μm) and waxy potato starch (20-30 μm) were modified with octenylsuccinic anhydride. Results showed that octenylsuccinylation caused a significant increase in the contact angle, and there was a weak positive linear correlation with the emulsifying capacity of the starch granules. After octenylsuccinylation, smaller particles of octenylsuccinate-starch granules exhibited better emulsifying properties with smaller droplet size and lower creaming index. Overall, both octenylsuccinylation and particle size have important effects on the emulsifying properties of starch granules as Pickering stabilizers. This study could be useful in the design and development of starch-based Pickering emulsifiers, and provide potential applications in the food and pharmaceutical industries

    SiMMap: a web server for inferring site-moiety map to recognize interaction preferences between protein pockets and compound moieties

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    The protein–ligand interacting mechanism is essential to biological processes and drug discovery. The SiMMap server statistically derives site-moiety map with several anchors, which describe the relationship between the moiety preferences and physico-chemical properties of the binding site, from the interaction profiles between query target protein and its docked (or co-crystallized) compounds. Each anchor includes three basic elements: a binding pocket with conserved interacting residues, the moiety composition of query compounds and pocket–moiety interaction type (electrostatic, hydrogen bonding or van der Waals). We provide initial validation of the site-moiety map on three targets, thymidine kinase, and estrogen receptors of antagonists and agonists. Experimental results show that an anchor is often a hot spot and the site-moiety map can help to assemble potential leads by optimal steric, hydrogen bonding and electronic moieties. When a compound highly agrees with anchors of site-moiety map, this compound often activates or inhibits the target protein. We believe that the site-moiety map is useful for drug discovery and understanding biological mechanisms. The SiMMap web server is available at http://simfam.life.nctu.edu.tw/

    Does Long-Term Use of Silver Nanoparticles Have Persistent Inhibitory Effect on H. pylori Based on Mongolian Gerbil’s Model?

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    It is urgent to find alternative agents due to increasing failure rate of Helicobacter pylori (H. pylori) eradication. The study surveyed the long-term effect of silver nanoparticles (AgNP) on H. pylori based on Mongolian gerbil's model

    Preparation, Characterization, and Properties of Polyurethane-Grafted Multiwalled Carbon Nanotubes and Derived Polyurethane Nanocomposites

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    We incorporated hydroxyl groups into the polyurethane backbone and then used the “grafting to” approach to functionalize the multiwalled carbon nanotubes (MWNTs) via the esterification reaction between MWNTs and segmented polyurethanes (PUs). X-ray photoelectron spectroscopy (XPS) spectra showed that the sidewalls of MWNTs had been functionalized with acid treatment, and the amount of COOH increased with increasing acid treatment time. FTIR spectra further confirmed that PU was covalently attached to the sidewalls of MWNTs. The functionalized acid amount and the grafted PU amount were determined by thermogravimetric analyses (TGAs). Comparative studies based on SEM images of the PU-functionalized and chemically defunctionalized MWNT samples also revealed the covalent coating character. Dynamic mechanical analysis (DMA) of nanocomposite films prepared from PU and PU-functionalized MWNTs showed enhanced mechanical properties and increased soft segment . Tensile properties indicated that PU-functionalized MWNTs were effective reinforcing fillers for the polyurethane matrix

    Lymphotoxin Is Required for Maintaining Physiological Levels of Serum IgE That Minimizes Th1-mediated Airway Inflammation

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    Although elevated levels of IgE in asthmatic patients are strongly associated with lung infiltration by activated T helper (Th) 2 cells, the physiological role of immunoglobulin E (IgE) in the airway remains largely undefined. Lymphotoxin-deficient α (LTα−/−) mice exhibit increased airway inflammation, paradoxically accompanied by diminished levels of IgE and reduced airway hyperresponsiveness in response to both environmental and induced antigen challenge. The severe lung inflammation in LTα−/− mice is Th1 in nature and can be alleviated by IgE reconstitution. Conversely, depletion of IgE in wild-type mice recapitulates the lung pathologies of LTα−/− mice. Therefore, this work has revealed that lymphotoxin is essential for IgE production, and a physiological role of IgE in the airway may consist of maintaining the balance of Th1 and Th2 responses to prevent aberrant inflammation

    MOAP-1 Mediates Fas-Induced Apoptosis in Liver by Facilitating tBid Recruitment to Mitochondria

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    SummaryFas apoptotic signaling regulates diverse physiological processes. Acute activation of Fas signaling triggers massive apoptosis in liver. Upon Fas receptor stimulation, the BH3-only protein Bid is cleaved into the active form, tBid. Subsequent tBid recruitment to mitochondria, which is facilitated by its receptor MTCH2 at the outer mitochondrial membrane (OMM), is a critical step for commitment to apoptosis via the effector proteins Bax or Bak. MOAP-1 is a Bax-binding protein enriched at the OMM. Here, we show that MOAP-1-deficient mice are resistant to Fas-induced hepatocellular apoptosis and lethality. In the absence of MOAP-1, mitochondrial accumulation of tBid is markedly impaired. MOAP-1 binds to MTCH2, and this interaction appears necessary for MTCH2 to engage tBid. These findings reveal a role for MOAP-1 in Fas signaling in the liver by promoting MTCH2-mediated tBid recruitment to mitochondria
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