193 research outputs found

    Pricing Strategies for User-Provided Connectivity Services

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    User-provided connectivity (UPC) services offer a possible alternative, orcomplement, to existing infrastructure-based connectivity. A userallows other users to occasionally connect through its home base inexchange for reciprocation, or possibly compensation. This service modelexhibits strong positive and negative externalities. A large user basemakes the service more attractive, as it offers more connectivity options toroaming users, but it also implies a greater volume of (roaming) trafficpassing through a user\u27s home base, which can increase congestion. Theseinteractions make it difficult to predict the eventual success of such aservice offering, and in particular how to effectively price it. This paperinvestigates a two-price policy where the first price is an introductory price that expires onceservice adoption reaches a certain level. The paper uses a simplifiedanalytical model to investigate pricing strategies under this policy, and their sensitivity to changesin system parameters. The insight and practicalguidelines this yields are validated numerically under morerealistic conditions

    The crosslink density of styrene butadiene rubber/nano copper oxide nanocomposites

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    Styrene butadiene rubber (SBR) is one of the most applicant rubbers in the world which could be used in the industrial usages and medical applications. In other some works, combination of styrene butadiene rubber with other rubbers could be used for composite and nanocomposites applications. In this paper, crosslink density of rubber based nanocomposites have been investigated by swelling test. Results showed that nano copper oxide nano copper oxide affect the crosslink density content of nanocomposites with presence of nano copper oxide. Moreover, extraction and swelling tests of nanocomposites has been carried out. The results showed that the nano copper oxide increased the amount of average molecular weight between two crosslinks

    The low abundance of CpG in the SARS-CoV-2 genome is not an evolutionarily signature of ZAP

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    The zinc finger antiviral protein (ZAP) is known to restrict viral replication by binding to the CpG rich regions of viral RNA, and subsequently inducing viral RNA degradation. This enzyme has recently been shown to be capable of restricting SARS-CoV-2. These data have led to the hypothesis that the low abundance of CpG in the SARS-CoV-2 genome is due to an evolutionary pressure exerted by the host ZAP. To investigate this hypothesis, we performed a detailed analysis of many coronavirus sequences and ZAP RNA binding preference data. Our analyses showed neither evidence for an evolutionary pressure acting specifically on CpG dinucleotides, nor a link between the activity of ZAP and the low CpG abundance of the SARS-CoV-2 genome

    RRM2 (ribonucleotide reductase M2)

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    Ribonucleotide reductase subunit M2 (RRM2) is located in chromosome-2 p25-p24, converts ribonucleotides to deoxynucleotides which is required for DNA polymerization and repair. It has been shown that RMM2 plays a key role in DNA synthesis, cell growth, and drug resistance of cancer cells. There is accumulating evidence that alteration in the expression level of RRM2 can have a substantial impact on the biological characteristics of cancer cells, including tumor initiation and progression, suggesting its role as a prognostic factor and a possible therapeutic target for cancer therapy. Therefore, this review highlights several recent and clinically relevant aspects of the expression and function of RRM2 in human cancer

    Inhibition of HERG1 K+ channel protein expression decreases cell proliferation of human small cell lung cancer cells

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    HERG (human ether-à-go-go-related gene) K+ currents fulfill important ionic functions in cardiac and other excitable cells. In addition, HERG channels influence cell growth and migration in various types of tumor cells. The mechanisms underlying these functions are still not resolved. Here, we investigated the role of HERG channels for cell growth in a cell line (SW2) derived from small cell lung cancer (SCLC), a malignant variant of lung cancer. The two HERG1 isoforms (HERG1a, HERG1b) as well as HERG2 and HERG3 are expressed in SW2 cells. Inhibition of HERG currents by acute or sustained application of E-4031, a specific ERG channel blocker, depolarized SW2 cells by 10–15 mV. This result indicated that HERG K+ conductance contributes considerably to the maintenance of the resting potential of about −45 mV. Blockage of HERG channels by E-4031 for up to 72 h did not affect cell proliferation. In contrast, siRNA-induced inhibition of HERG1 protein expression decreased cell proliferation by about 50%. Reduction of HERG1 protein expression was confirmed by Western blots. HERG current was almost absent in SW2 cells transfected with siRNA against HERG1. Qualitatively similar results were obtained in three other SCLC cell lines (OH1, OH3, H82), suggesting that the HERG1 channel protein is involved in SCLC cell growth, whereas the ion-conducting function of HERG1 seems not to be important for cell growth

    Aquaculture code of conduct and mechanization management

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    In this report rules and focal points about code of conduct for cold water farm, warm water establishment, mechanization management and oxygen generators are collected and discussed. One of the most important point difference between aquaculture engineering with mechanization. Mechanization is improvement of management level from ancient to better by some special tools but aquaculture engineering can do by any vessel in every management
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