排序方式: 共有110条查询结果,搜索用时 15 毫秒
21.
Siavash Riahi Farhang Jalali Farahani Abdolmajid Bayandori Moghaddam Mohammad Reza Ganjali Parviz Norouzi 《Journal of Molecular Structure》2008,850(1-3):48-54
This research presents calculations and computation of two anticoagulant derivatives electrode potentials in methanol. For this purpose, the ab initio molecular orbital calculations (HF) and density functional theory (DFT) together with the 6-31G(d) basis set were utilized. The calculated values were compared with the experimental values obtained by linear sweep voltammetry. The observed and the calculated changes in the reduction potential of the anticoagulant derivatives differed from those of the reference compound (catechol), being less than 20 mV. In this way, a method was provided, by which the reduction potentials of the related molecules could be predicted very accurately. Actually, the resulting data illustrated that the method was likely to be useful for the prediction of biomolecules electrode potentials in different aprotic solvents. The bond lengths, bond angles and dipole moment of the studied compounds were calculated in two different solvents and the solvent effects were discussed. 相似文献
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Reza Zanjirani Farahani Zvi Drezner Nasrin Asgari 《Annals of Operations Research》2009,167(1):353-368
In this paper a single facility location problem with multiple relocation opportunities is investigated. The weight associated
with each demand point is a known function of time. We consider either rectilinear, or squared Euclidean, or Euclidean distances.
Relocations can take place at pre-determined times. The objective function is to minimize the total location and relocation
costs. An algorithm which finds the optimal locations, relocation times and the total cost, for all three types of distance
measurements and various weight functions, is developed. Locations are found using constant weights, and relocations times
are the solution to a Dynamic Programming or Binary Integer Programming (BIP) model. The time horizon can be finite or infinite. 相似文献
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In this paper we study thermodynamics, statistics and spectroscopic aspects of a charged black hole with a scalar hair coupled to the gravity in (2+1) dimensions. We obtained effects of the black hole charge and scalar field on the thermodynamical and statistical quantities. We find that scalar charge may increase entropy, temperature and probability, while may decrease black hole mass, free and internal energy. Also electric charge increases probability and decreases temperature and internal energy. Also we investigate stability of the system and find that the thermodynamical stability exists. 相似文献
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Along the same line as that in Ono (Ann Pure Appl Logic 161:246–250, 2009), a proof-theoretic approach to Glivenko theorems is developed here for substructural predicate logics relative not only to classical predicate logic but also to arbitrary involutive substructural predicate logics over intuitionistic linear predicate logic without exponentials QFL e . It is shown that there exists the weakest logic over QFL e among substructural predicate logics for which the Glivenko theorem holds. Negative translations of substructural predicate logics are studied by using the same approach. First, a negative translation, called extended Kuroda translation is introduced. Then a translation result of an arbitrary involutive substructural predicate logics over QFL e is shown, and the existence of the weakest logic is proved among such logics for which the extended Kuroda translation works. They are obtained by a slight modification of the proof of the Glivenko theorem. Relations of our extended Kuroda translation with other standard negative translations will be discussed. Lastly, algebraic aspects of these results will be mentioned briefly. In this way, a clear and comprehensive understanding of Glivenko theorems and negative translations will be obtained from a substructural viewpoint. 相似文献
25.
ArF laser surface modification of polyethersulfone film: Effect of laser fluence in improving surface biocompatibility 总被引:1,自引:0,他引:1
H. Pazokian S. Jelvani M. MollabashiJ. Barzin G. Azizabadi Farahani 《Applied Surface Science》2011,257(14):6186-6190
ArF laser treatment of polyethersulfone (PES) films was performed to improve biocompatibility of surfaces. For this purpose, the threshold fluence for laser ablation of PES was obtained from experimental measurements and then samples were irradiated at 2 separate ranges of fluences, i.e. below and above the ablation threshold. In order to investigate the physico-chemical changes, the modified surfaces were characterized by attenuated total reflectance (ATR) infrared spectroscopy and contact-angle measurements. The biocompatibility of the treated samples in comparison to those untreated was examined in vitro using a platelet adhesion test. The number of adhered platelets was obtained using the lactate dehydrogenase (LDH) method. For surfaces irradiated below the ablation threshold, a high reduction in the number of the adhered platelets was observed; while this number increased in samples treated at the fluence above the ablation threshold. The change in platelet adhesion was attributed to the change in chemistry and roughness of the irradiated surfaces. 相似文献
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27.
The effect of solvent composition on vancomycin hydrochloride and free base vancomycin release from in situ forming implants 下载免费PDF全文
In situ forming drug delivery systems that are formed by solvent‐induced phase inversion have attracted extensive attention in sustained delivery of peptides and proteins. Based on the findings of our previous studies, N‐methyl‐2‐pyrrolidone (NMP) and acetone are two solvents that could improve the release profile of vancomycin from in situ forming systems based on poly(D,L‐lactide‐co‐glycolic acid). In this study, the effect of different compositions of these solvents on the release profile of hydrochloride and free base forms of vancomycin was investigated. To this end, several formulations with vancomycin (either hydrochloride or free base form) and different proportions of NMP and acetone were prepared. The cumulative drug release at specified time was determined and tested against conventional kinetic models. The surface and cross‐sectional morphology of implants were investigated by SEM. The experimental results showed that as solvent composition changed, the amount of vancomycin release during the first 12 h changed, too. The use of free base vancomycin resulted in an extended vancomycin release profile with less initial burst release. The formulation containing free base vancomycin and mixed solvents of acetone and NMP in 2:1 ratio released 70% of loaded drug in 6 weeks with near zero‐order kinetic. The best kinetic model to fit the in vitro release profiles was found to be Peppas–Sahlin model. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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Reza Zanjirani Farahani Shabnam Rezapour Tammy Drezner Ameneh Moharerhaye Esfahani Mehdi Amiri-Aref 《The Journal of the Operational Research Society》2015,66(7):1182-1205
This paper investigates the network design problem of a two-level supply chain (SC), which is applicable for industries such as automotive, fuel and tyre manufacturing. Models presented in this paper aim at locating retail facilities of an SC and identifying their required capacities in the presence of existing competing retailers of a rival SC. We consider feasible locating space of the retail facilities on the continuous plane with bounded constraints and static competition among the rivals of the markets with deterministic demands. The problem is used for both essential and luxury product cases; hence, we consider elastic and inelastic demands, both. The models discussed in this paper are non-linear and non-convex which are difficult to solve. We use interval branch-and-bound as optimization algorithm for small size single-retailer problems, but for large-scale, multi-retailer problems we need to have more efficient methods. Therefore, we apply a heuristic algorithm (H1), a simulated annealing (SA) algorithm, an interior point (IP) algorithm, a genetic algorithm (GA) and a pattern search algorithm for solving multi-retailer problem with elastic and inelastic demands. Computational results obtained from performing different solution approaches for both elastic and inelastic show that mostly IP, PS, and H1 methods outperform the other approaches. The computational results on a real-life case are also promising. Several extended mathematical models and an example of a typical case with details are presented in the appendices of the paper. 相似文献
30.
Hadi Farahani Parviz Norouzi Rassoul Dinarvand Mohammad Reza Ganjali 《Journal of separation science》2009,32(2):314-320
A simple and sensitive methodology based on liquid‐phase microextraction (LPME) followed by GC‐MS, was developed for the determination of trihalomethanes (THMs) in drinking water. A microdrop of organic solvent was floated on the surface of the aqueous sample and it was agitated for a desired time. Then, the sample vial was cooled by inserting it into an ice bath for 4 min. The solidified solvent was transferred into a suitable vial and immediately melted. The extract was directly injected into the GC. Microextraction efficiency factors were investigated and optimized: 7 μL 1‐undecanol microdrop exposed for 15 min floated on the surface of a 10.0 mL aqueous sample with the temperature of 60°C containing 3 M of NaCl and stirred at 750 rpm. Under the selected conditions, enrichment factors (EFs) up to 482‐fold, LOD of 0.03–0.08 μg/L (S/N = 3) and dynamic linear ranges of 0.10–100 μg/L were obtained. A reasonable repeatability (RSD < 8.6%, n = 8) with satisfactory linearity (r2 ? 0.9947) of results illustrated a good performance of the present method. The protocol proved to be rapid, cost‐effective, and is a green procedure for the screening purposes. 相似文献