960 research outputs found

    Optimal managerial decision model in a closed-loop supply chain for a retailer to collect used products with different transfer policy

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    In recent years, the concerns of environmental and resource issues are growing. Due to a great deal of attention for closed-loop supply chains, collection behaviour of used products from public consumers becomes more and more important. This paper proposes an inventory model for retailer with new products and used products and the retailer is the decision maker who follows the rule of Economic Ordering Quantity (EOQ) model. We assumed that the retailer not only sells products but also collects those sold used products. The proposed problem faced by the retailer is formulated as a cost-minimization problem where the replenishment quantity of new products and the return rate of used products are the decision variables and an efficient iterative algorithm is provided to search for the solution. Furthermore, we extend our model to consider the "not lot for lot policy" inventory model for forward channel and reverse channel and determine the optimal management policy. Finally, we discuss the economical decision modelling for a retailer to analyse the willingness of collecting used products

    Dual Targeting of Tumor Angiogenesis and Chemotherapy by Endostatin- Cytosine Deaminase-Uracil PhosphoribosylTransferase

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    Antiangiogenesis is a promising anti-tumor strategy through inhibition tumor vascularformation to suppress tumor growth. Targeting specific VEGF/R has been showntherapeutic benefits in many cancer types and become a first approvedantiangiogenic modalities by Food and Drug Administration (FDA) in United States.However, interruption of homeostasis in normal tissues that is likely due to theinhibition of VEGF/R signaling pathway induces unfavorable side effects. Moreover,cytostatic nature of antiangiogenic drugs frequently causes less tumor cell specifickilling activity, and cancer cells escaped from cell death induced by these drugseven gain more malignant phenotypes, resulting in tumor invasion and metastasis.To overcome these issues, we developed a novel anti-tumor therapeutic EndoCDfusion protein which linked endostatin (Endo) to cytosine deaminase-uracilvphosphoribosyl transferase (CD). Endo targets unique tumor endothelial cells toprovide tumor-specific antiangiogenesis activity and also carries CD to the localtumor area, where it serves nontoxic prodrug 5-fluorocytosine (5-FC) enzymaticconversion reaction to anti-metabolite chemotherapy drug 5-fluorouracil (5-FU). Wedemonstrated that 5-FU concentration was highly increased in tumor sites, resultingin high level of endothelial cells and tumor cells cytotoxic efficacy. Furthermore,EndoCD/5-FC therapy decreased tumor growth and colorectal liver metastasisincident compared with bevacizumab/5-FU treatment in human breast and colorectalliver metastasis orthotropic animal models. In cardiotoxicity safety profile,EndoCD/5-FC is a contrast to bevacizumab/5-FU; lower risk of cardiotoxicityinduction or heart function failure was found in EndoCD/5-FC treatment thanbevacizumab/5-FU does in mice. EndoCD/5-FC showed more potent therapeuticefficacy with high safety profile and provided stronger tumor invasion or metastasisinhibition than antiangiogenic drugs. Together, EndoCD fusion protein with 5-FCshowed dual tumor targeting activities including antiangiogenesis and tumor localchemotherapy, and it could serve as an alternative option for antiangiogenic therapy

    A Comparative Study on Spin-Orbit Torque Efficiencies from W/ferromagnetic and W/ferrimagnetic Heterostructures

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    It has been shown that W in its resistive form possesses the largest spin-Hall ratio among all heavy transition metals, which makes it a good candidate for generating efficient dampinglike spin-orbit torque (DL-SOT) acting upon adjacent ferromagnetic or ferrimagnetic (FM) layer. Here we provide a systematic study on the spin transport properties of W/FM magnetic heterostructures with the FM layer being ferromagnetic Co20_{20}Fe60_{60}B20_{20} or ferrimagnetic Co63_{63}Tb37_{37} with perpendicular magnetic anisotropy. The DL-SOT efficiency ∣ξDL∣|\xi_{DL}|, which is characterized by a current-induced hysteresis loop shift method, is found to be correlated to the microstructure of W buffer layer in both W/Co20_{20}Fe60_{60}B20_{20} and W/Co63_{63}Tb37_{37} systems. Maximum values of ∣ξDL∣≈0.144|\xi_{DL}|\approx 0.144 and ∣ξDL∣≈0.116|\xi_{DL}|\approx 0.116 are achieved when the W layer is partially amorphous in the W/Co20_{20}Fe60_{60}B20_{20} and W/Co63_{63}Tb37_{37} heterostructures, respectively. Our results suggest that the spin Hall effect from resistive phase of W can be utilized to effectively control both ferromagnetic and ferrimagnetic layers through a DL-SOT mechanism
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