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931.
932.
This research forecasts peak call volume of a centralized after‐hours call center for rural electric cooperatives to help the call center determine staffing levels. A Gaussian copula is used to capture the dependence among non‐normal distributions. Using a centralized call center reduces costs by approximately 75% compared to having individual call centers at each cooperative. Adding cooperatives to the centralized call center is projected to further decrease costs per member. An out‐of‐sample forecasting exercise after the call center expanded validated the model's forecast that additional cooperatives could be added without a proportional increase in the peak number of calls. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
933.
Zinc-indium-tin oxide (ZITO) films were grown by pulsed-laser deposition.Three different material compositions were investigated:ZITO-30,ZITO-50 and ZITO-70 in which 30%,50% and 70%,respectively,of the... 相似文献
934.
Alexander V. Zhdanov Ruslan I. Dmitriev Dmitri B. Papkovsky 《Cellular and molecular life sciences : CMLS》2011,68(5):903-917
Bafilomycin A1 (Baf) induces an elevation of cytosolic Ca2+ and acidification in neuronal cells via inhibition of the V-ATPase. Also, Baf uncouples mitochondria in differentiated PC12
(dPC12), dSH-SY5Y cells and cerebellar granule neurons, and markedly elevates their respiration. This respiratory response in dPC12 is accompanied by morphological changes in the mitochondria and decreases the mitochondrial pH, Ca2+ and ΔΨm. The response to Baf is regulated by cytosolic Ca2+ fluxes from the endoplasmic reticulum. Inhibition of permeability transition pore opening increases the depolarizing effect
of Baf on the ΔΨm. Baf induces stochastic flickering of the ΔΨm with a period of 20 ± 10 s. Under conditions of suppressed
ATP production by glycolysis, oxidative phosphorylation impaired by Baf does not provide cells with sufficient ATP levels.
Cells treated with Baf become more susceptible to excitation with KCl. Such mitochondrial uncoupling may play a role in a
number of (patho)physiological conditions induced by Baf. 相似文献
935.
936.
Aquatic sex pheromone from a male tree frog. 总被引:3,自引:0,他引:3
937.
938.
Mutations in a new gene encoding a thiamine transporter cause thiamine-responsive megaloblastic anaemia syndrome. 总被引:7,自引:0,他引:7
Thiamine-responsive megaloblastic anaemia syndrome (TRMA; MIM 249270) is an autosomal recessive disorder with features that include megaloblastic anaemia, mild thrombocytopenia and leucopenia, sensorineural deafness and diabetes mellitus. Treatment with pharmacologic doses of thiamine ameliorates the megaloblastic anaemia and diabetes mellitus. A defect in the plasma membrane transport of thiamine has been demonstrated in erythrocytes and cultured skin fibroblasts from TRMA patients. The gene causing TRMA was assigned to 1q23.2-q23.3 by linkage analysis. Here we report the cloning of a new gene, SLC19A2, identified from high-through-put genomic sequences due to homology with SLC19A1, encoding reduced folate carrier 1 (refs 8-10). We cloned the entire coding region by screening a human fetal brain cDNA library. SLC19A2 encodes a protein (of 497 aa) predicted to have 12 transmembrane domains. We identified 2 frameshift mutations in exon 2. a 1-bp insertion and a 2-bp deletion, among four Iranian families with TRMA. The sequence homology and predicted structure of SLC19A2, as well as its role in TRMA, suggest that its gene product is a thiamine carrier, the first to be identified in complex eukaryotes. 相似文献
939.
A family of mammalian Na+-dependent L-ascorbic acid transporters. 总被引:10,自引:0,他引:10
H Tsukaguchi T Tokui B Mackenzie U V Berger X Z Chen Y Wang R F Brubaker M A Hediger 《Nature》1999,399(6731):70-75
Vitamin C (L-ascorbic acid) is essential for many enzymatic reactions, in which it serves to maintain prosthetic metal ions in their reduced forms (for example, Fe2+, Cu+), and for scavenging free radicals in order to protect tissues from oxidative damage. The facilitative sugar transporters of the GLUT type can transport the oxidized form of the vitamin, dehydroascorbic acid, but these transporters are unlikely to allow significant physiological amounts of vitamin C to be taken up in the presence of normal glucose concentrations, because the vitamin is present in plasma essentially only in its reduced form. Here we describe the isolation of two L-ascorbic acid transporters, SVCT1 and SVCT2, from rat complementary DNA libraries, as the first step in investigating the importance of L-ascorbic acid transport in regulating the supply and metabolism of vitamin C. We find that SVCT1 and SVCT2 each mediate concentrative, high-affinity L-ascorbic acid transport that is stereospecific and is driven by the Na+ electrochemical gradient. Despite their close sequence homology and similar functions, the two isoforms of the transporter are discretely distributed: SVCT1 is mainly confined to epithelial systems (intestine, kidney, liver), whereas SVCT2 serves a host of metabolically active cells and specialized tissues in the brain, eye and other organs. 相似文献
940.
E A Rogaeva S Premkumar J Grubber L Serneels W K Scott T Kawarai Y Song D L Hill S M Abou-Donia E R Martin J J Vance G Yu A Orlacchio Y Pei M Nishimura A Supala B Roberge A M Saunders A D Roses D Schmechel A Crane-Gatherum S Sorbi A Bruni G W Small P M Conneally J L Haines F Van Leuven P H St George-Hyslop L A Farrer M A Pericak-Vance 《Nature genetics》1999,22(1):19-22