256 research outputs found

    A polyhedral approach to the discrete lot-sizing and scheduling problem

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    On the discrete lot-sizing and scheduling problem with Wagner-Whitin costs

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    We consider the single-item discrete lot-sizing and scheduling problem. We present a partial linear description of the convex hull of feasible solutions that solves this problem in the presence of Wagner-Whitin costs.operations research and management science;

    Elucidation of xenobiotic metabolism pathways in human skin and human skin models by proteomic profiling

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    Human skin has the capacity to metabolise foreign chemicals (xenobiotics), but knowledge of the various enzymes involved is incomplete. A broad-based unbiased proteomics approach was used to describe the profile of xenobiotic metabolising enzymes present in human skin and hence indicate principal routes of metabolism of xenobiotic compounds. Several in vitro models of human skin have been developed for the purpose of safety assessment of chemicals. The suitability of these epidermal models for studies involving biotransformation was assessed by comparing their profiles of xenobiotic metabolising enzymes with those of human skin

    Проблеми управління експлуатаційним потенціалом газорозподільчих підприємств міста

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    У статті узагальнені проблеми управління експлуатаційним потенціалом газорозподільчих підприємств міста, визначено причини їх виникнення та запропоновано шляхи вирішення. Визначено коло завдань держави, які мають бути вирішені, щоб експлуатація газорозподільчих мереж у місті була більш ефективною та економічно доцільною

    Vaccinia virus utilizes microtubules for movement to the cell surface

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    Vaccinia virus (VV) egress has been studied using confocal, video, and electron microscopy. Previously, intracellular-enveloped virus (IEV) particles were proposed to induce the polymerization of actin tails, which propel IEV particles to the cell surface. However, data presented support an alternative model in which microtubules transport virions to the cell surface and actin tails form beneath cell-associated enveloped virus (CEV) particles at the cell surface. Thus, VV is unique in using both microtubules and actin filaments for egress. The following data support this proposal. (a) Microscopy detected actin tails at the surface but not the center of cells. (b) VV mutants lacking the A33R, A34R, or A36R proteins are unable to induce actin tail formation but produce CEV and extracellular-enveloped virus. (c) CEV formation is inhibited by nocodazole but not cytochalasin D or 4-amino-5-(4-methylphenyl)-7-(t-butyl)pyrazolo(3,4-d)pyrimidine (PP1). (d) IEV particles tagged with the enhanced green fluorescent protein fused to the VV B5R protein moved inside cells at 60 μm/min. This movement was stop-start, was along defined pathways, and was inhibited reversibly by nocodazole. This velocity was 20-fold greater than VV movement on actin tails and consonant with the rate of movement of organelles along microtubules
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