103 research outputs found

    Arginase from kiwifruit: properties and seasonal variation

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    The in vitro activity of arginase (EC 3.5.3.1) was investigated in youngest-mature leaves and roots (1-3 mm diameter) of kiwifruit vines (Actinidia deliciosa var. deliciosa) during an annual growth cycle, and enzyme from root material partially purified. No seasonal trend in the specific activity of arginase was observed in roots. Measurements in leaves, however, rose gradually during early growth and plateaued c. 17 weeks after budbreak. Changes in arginase activity were not correlated with changes in the concentration of arginine (substrate) or glutamine (likely end-product of arginine catabolism) in either tissue during the growth cycle. Purification was by (NH4)2SO4 precipitation and DEAE-cellulose chromatography. The kinetic properties of the enzyme, purified 60-fold over that in crude extracts, indicated a pH optimum of 8.8, and a Km (L-arginine) of 7.85 mM. Partially-purified enzyme was deactivated by dialysis against EDTA, and reactivated in the presence of MnÂČâș, CoÂČâș, and NiÂČâș

    Real-time, label-free, intraoperative visualization of peripheral nerves and microvasculatures using multimodal optical imaging techniques

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    Accurate, real-time identification and display of critical anatomic structures, such as the nerve and vasculature structures, are critical for reducing complications and improving surgical outcomes. Human vision is frequently limited in clearly distinguishing and contrasting these structures. We present a novel imaging system, which enables noninvasive visualization of critical anatomic structures during surgical dissection. Peripheral nerves are visualized by a snapshot polarimetry that calculates the anisotropic optical properties. Vascular structures, both venous and arterial, are identified and monitored in real-time using a near-infrared laser-speckle-contrast imaging. We evaluate the system by performing in vivo animal studies with qualitative comparison by contrast-agent-aided fluorescence imaging

    Salicylic acid-based organic dyes acting as the photosensitizer for solar cells

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    A D-π-A metal-free organic dye, featuring salicylic acid as a novel acceptor/anchoring unit, has been designed, synthesized and applied to dye-sensitized solar cell. The detailed photophysical, electrochemical, photovoltaic and sensitizing properties of the organic dye were investigated, in addition to the computational studies of the dye and dye-(TiO2)6 system. A solar cell device using this new organic dye as a sensitizer produced a solar to electric power conversion efficiency (PCE) of 3.49% (J(sc) = 6.69 mAcm-2, V(oc) = 0.74 V and ff = 0.70) under 100 mWcm(-2) simulated AM 1.5 G solar irradiation, demonstrating that the salicylic acid-based organic dye is a suitable alternative to currently used organometallic dye

    Inhibition of HIV replication by amino-sugar derivatives

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    AbstractThe plant alkaloids castanospermine, dihydroxymethyldihydroxypyrrolidine and deoxynojirimycin have recently been shown to have potential anti-HIV activity [(1987) Proc. Natl. Acad. Sci. USA 84, 8120–8124; (1987) Nature 330, 74–77; (1987) Lancet i, 1025–1026]. They are thought to act by inhibiting α-glucosidase I, an enzyme involved in the processing of N-linked oligosaccharides on glycoproteins. We report here the relative efficacy of a spectrum of amino-sugar derivatives as inhibition of HIV cytopathicity. Several α-glucosidase inhibitors and α-fucosidase inhibitors were found to be active at concentrations which were non-cytotoxic

    Altering the DNA-binding specificity of Mu transposase in vitro

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    Association of Human Papillomavirus and Extra-genital Bowen’s Disease (Squamous Cell Carcinoma in situ): A Systematic Review

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    Supplementary materials for publication JAAD-D-20-02223 (Namgoong et al. Association of Human Papillomavirus and Extra-genital Bowen’s Disease (Squamous Cell Carcinoma in situ): A Systematic Review

    Association of Human Papillomavirus and Extra-genital Bowen’s Disease (Squamous Cell Carcinoma in situ): A Systematic Review

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    Supplementary materials for publication JAAD-D-20-02223 (Namgoong et al. Association of Human Papillomavirus and Extra-genital Bowen’s Disease (Squamous Cell Carcinoma in situ): A Systematic Review

    INTERCEPTION OF AN IMINIUM ION EQUIVALENT BY INTRAMOLECULAR NUCLEOPHILIC-ATTACK BY A SILYL ETHER DURING LITHIUM ALUMINUM-HYDRIDE REDUCTION OF A TERTIARY LACTAM

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    The efficient formation of a bicyclic oxazolidine by lithium aluminium hydride reduction of a tertiary amide provides an example of intramolecular nucleophilic capture of an iminium ion equivalent by the oxygen of a silyl ether
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