Showing papers by "Kharazmi University published in 2015"

Teacher Self-Efficacy and Teacher Burnout: A Study of Relations

Abstract: In any teaching and learning setting, there are some variables that play a highly significant role in both teachers' and learners' performance. Two of these influential psychological domains in educational context include self-efficacy and burnout. This study is conducted to investigate the relationship between the self-efficacy of Iranian teachers of English and their reports of burnout. The data was collected through application of two questionnaires. The Maslach Burnout Inventory (MBI; Maslach& Jackson 1981, 1986) and Teacher Efficacy Scales (Woolfolk& Hoy, 1990) were administered to ten university teachers. After obtaining the raw data, the SPSS software (version 16) was used to change the data into numerical interpretable forms. In order to determine the relationship between self-efficacy and teachers' burnout, correlational analysis was employed. The results showed that participants' self-efficacy has a reverse relationship with their burnout.

Silver Nanoparticles Biosynthesized Using Achillea biebersteinii Flower Extract: Apoptosis Induction in MCF-7 Cells via Caspase Activation and Regulation of Bax and Bcl-2 Gene Expression

Abstract: Silver nanoparticles (Ag-NPs), the most popular nanoparticles, possess unique properties Achillea biebersteinii is a plant of the Asteraceae family rich in active antitumor components The aim of this research was the characterization and investigation of the cytotoxic properties of Ag-NPs synthesized using A biebersteinii flower extract, on a human breast cancer cell line The Ag-NPs were synthesized after approximately 180 min of reaction at 40 °C, then they were characterized by UV-visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and dynamic light scattering (DLS) The anti-apoptosis effect of Ag-NPs on the MCF-7 cell line was investigated by MTT assay, DAPI and acridine orange staining and caspase activity The transcriptional expression of bax, bcl-2, caspase-3, -8 and -9 were also evaluated by RT-PCR The TEM images revealed that the Ag-NPs morphology had a different shape The DLS indicated that the average hydrodynamic diameter of the biosynthesized Ag-NPs was around 12 nm By UV-visible spectroscopy the strongest absorbance peak was observed at 460 nm The FTIR results also showed interaction between the plant extract and Ag-NPs due to the similarity in the peak patterns The EDS results showed that Ag-NPs display an absorption peak at 3 keV, indicating the presence of the element silver The Ag-NPs caused a dose-dependent decrease in cell viability, fragmentation in nucleic acid, inhibited the proliferation and induction of apoptosis on MCF-7 by suppressing specific cell cycle genes, and simulation programmed cell dead genes Further investigation is required to establish the potential of this novel and promising approach in cancer therapy

Preparation and characterization of antifouling graphene oxide/polyethersulfone ultrafiltration membrane: Application in MBR for dairy wastewater treatment

Abstract: This study was performed to investigate effect of different concentrations of graphene oxide (GO) nanoplates on fouling mitigation of polyethersulfone (PES) membranes applied in membrane bioreactor (MBR) to treatment milk processing wastewater. The GO was prepared from graphite and characterized by FTIR, SEM and XRD. The mixed matrix membranes were prepared in three concentrations of 13, 15 and 17 wt% of PES polymer. Static contact angle of the membranes were decreased significantly with addition of the GO nanosheets caused to increasing of pure water flux and MWCO. Cross sectional SEM images showed that the finger-like pores for all of the GO embedded membranes were slightly wider than that of the unfilled PES membrane. Ultrafiltration performance and fouling resistance of the membranes were tested by filtration of activated sludge. With addition of GO nanoplates, fouling resistance ratio (FRR) of the nanocomposite membranes was improved. AFM images and FRR results presented that a membrane with smoother surface has greater fouling resistance ability. Based on antifouling and water flux results, the PES/GO membrane with 15 wt% of PES and GO content of 0.5 wt%, was selected as an optimal membrane and tested in MBR system. The MBR showed an increased capacity for removal of organic matter, both in terms of COD and BOD5 of milk processing wastewater. With increasing of MLSS concentration, flux of the membrane was increased due to a decrease in soluble microbial products and extracellular polymeric substance from the bacterial cells in the lower food to microorganism ratio (F/M).

Cryptanalysis and Improvement of an Improved Two Factor Authentication Protocol for Telecare Medical Information Systems

Abstract: Telecare medical information systems (TMIS) provides rapid and convenient health care services remotely. Efficient authentication is a prerequisite to guarantee the security and privacy of patients in TMIS. Authentication is used to verify the legality of the patients and TMIS server during remote access. Very recently Islam et al. (J. Med. Syst. 38(10):135, 2014) proposed a two factor authentication protocol for TMIS using elliptic curve cryptography (ECC) to improve Xu et al.'s (J. Med. Syst. 38(1):9994, 2014) protocol. They claimed their improved protocol to be efficient and provides all security requirements. However our analysis reveals that Islam et al.'s protocol suffers from user impersonation and server impersonation attacks. Furthermore we proposed an enhanced protocol. The proposed protocol while delivering all the virtues of Islam et al.'s protocol resists all known attacks.

An enhanced privacy preserving remote user authentication scheme with provable security

Abstract: Very recently, Kumari et al. proposed a symmetric key and smart card-based remote user password authentication scheme to enhance Chung et al.'s scheme. They claimed their enhanced scheme to provide anonymity while resisting all known attacks. In this paper, we analyze that Kumari et al.'s scheme is still vulnerable to anonymity violation attack as well as smart card stolen attack. Then we propose a supplemented scheme to overcome security weaknesses of Kumari et al.'s scheme. We have analyzed the security of the proposed scheme in random oracle model which confirms the robustness of the scheme against all known attacks. We have also verified the security of our scheme using automated tool ProVerif. Copyright © 2015 John Wiley & Sons, Ltd.

Optimizing a bi-objective multi-product multi-period three echelon supply chain network with warehouse reliability

Abstract: A bi-objective optimization model of a MP-MP 3-echelon SC network is derived.Uncertainties are involved in the services of the warehouses.The total cost is minimized while the total number of products dispatched is maximized.The best out of six MODM methods is selected to be used in GAMS.Numerical illustrations are provided to show the applicability of the proposed methodology. Bi-objective optimization of a multi-product multi-period three-echelon supply chain network consisting of manufacturing plants, distribution centers (DCs) each with uncertain services, and customer nodes is aimed in this paper. The two objectives are minimization of the total cost while maximizing the average number of products dispatched to customers. The decision variables are: (1) the number and the locations of reliable DCs in the network, (2) the optimum number of items produced by plants, (3) the optimum quantity of transported products, (4) the optimum inventory of products at DCs and plants, and (5) the optimum shortage quantity of the customer nodes. The problem is first formulated into the framework of a constrained bi-objective mixed integer linear programming model. Then, to solve the problem using the GAMS software, six multi-objective decision-making (MODM) methods are investigated in order to select the best in terms of total supply chain cost, total expected number of products dispatched to customers, and their required CPU time, simultaneously. At the end, some numerical illustrations are provided to show the applicability of the proposed methodology.

Al-HMS-20 catalyzed synthesis of pyrano[2,3- d ]pyrimidines and pyrido[2,3- d ]pyrimidines via three-component reaction

Abstract: A large library of pyrano[2,3-d]pyrimidines and pyrido[2,3-d]pyrimidines was synthesized through the reaction between various aromatic aldehydes, malononitrile and pyrimidine derivatives in the presence of Al-HMS-20 as the catalyst in EtOH at room temperature after 12 h. This multi-component approach is a very efficient and economical benign process.

Open access and sources of full-text articles in Google Scholar in different subject fields

Abstract: Google Scholar, a widely used academic search engine, plays a major role in finding free full-text versions of articles. But little is known about the sources of full-text files in Google Scholar. The aim of the study was to find out about the sources of full-text items and to look at subject differences in terms of number of versions, times cited, rate of open access availability and sources of full-text files. Three queries were created for each of 277 minor subject categories of Scopus. The queries were searched in Google Scholar and the first ten hits for each query were analyzed. Citations and patents were excluded from the results and the time frame was limited to 2004---2014. Results showed that 61.1 % of articles were accessible in full-text in Google Scholar; 80.8 % of full-text articles were publisher versions and 69.2 % of full-text articles were PDF. There was a significant difference between the means of times cited of full text items and non-full-text items. The highest rate of full text availability for articles belonged to life science (66.9 %). Publishers' websites were the main source of bibliographic information for non-full-text articles. For full-text articles, educational (edu, ac.xx etc.) and org domains were top two sources of full text files. ResearchGate was the top single website providing full-text files (10.5 % of full-text articles).

Optimization of a multiproduct economic production quantity problem with stochastic constraints using sequential quadratic programming

Abstract: A multiproduct single vendor-single buyer supply chain problem is modeled.To suite real-world environments, the model includes five stochastic constraints.The recently-developed SQP is used to solve the problem.Twenty numerical examples are solved in order to demonstrate the performance.The results show that SQP has better performance than the interior point method. In this paper, a multiproduct single vendor-single buyer supply chain problem is investigated based on the economic production quantity model developed for the buyer to minimize the inventory cost. The model to be more applicable for real-world supply chain problems contains five stochastic constraints including backordering cost, space, ordering, procurement, and available budget. The objective is to find the optimal order quantities of the products such that the total inventory cost is minimized while the constraints are satisfied. The recently-developed sequential quadratic programming (SQP), as one of the best optimization methods available in the literature, is used to solve the problem. Twenty numerical examples in 3 scales of small, medium, and large are solved in order to demonstrate the applicability of the proposed methodology and to evaluate its optimum performance. The results show that SQP has satisfactory performance in terms of optimum solutions, number of iterations to achieve the optimum solution, infeasibility, optimality error, and complementarity. Besides, the optimum performance of the SQP method is compared with the one of another exact method called interior point using the above numerical examples under similar conditions. The comparison results are in favor of the employed SQP. At the end, a sensitivity analysis is performed on the change rate of the objective function obtained based on the change rate of the variance of the order quantity.

A novel imperialist competitive algorithm for generalized traveling salesman problems

Abstract: A hybrid imperialist competitive algorithm is presented.It uses assimilation, destruction/construction and imperialist development schemes.The algorithm is calibrated using Taguchi method.For evaluation, it is compared against two effective existing algorithms. This paper deals with generalized traveling salesman problems. In this problem, all nodes are partitioned into some clusters and each cluster must be visited exactly once in a tour. We present an effective metaheuristic method hybridized with a local search procedure to solve this problem. The proposed algorithm is based on the imperialist competitive algorithm (ICA), which is a new socio-politically motivated global search strategy. ICA is enhanced by a novel encoding scheme, assimilation policy procedure, destruction/construction operator and imperialist development plans. Various parameters of the algorithm are analyzed to calibrate the algorithm by means of the Taguchi method. For the evaluation of the proposed algorithm, it is compared against two effective existing algorithms through a set of available instances. The results demonstrate the superiority of our algorithm in both solution quality and robustness of the solution.

Pre-ischemic exercise reduces apoptosis in hippocampal CA3 cells after cerebral ischemia by modulation of the Bax/Bcl-2 proteins ratio and prevention of caspase-3 activation.

Abstract: Ischemia induces physiological alterations in neurons that lead to cell death. This study investigated the effects of pre-ischemic exercise on CA3 neurons. Rats were divided into three groups. Animals in the exercise group were trained 5 days a week for 4 weeks. Ischemia was induced by occlusion of both common carotid arteries (CCAs) for 20 min. Apoptotic cell death was detected by TUNEL assay. Furthermore, expression of different proteins was determined by immunohistochemical staining. The number of TUNEL-positive cells was significantly increased in the ischemia group, but pre-ischemic exercise significantly reduced apoptotic cell death (P < 0.001). In addition, our results showed a significant increase in the Bax/Bcl-2 ratio in the ischemia group. Pre-ischemic exercise attenuated this ratio (P < 0.05). Furthermore, the number of active caspase-3-positive neurons was significantly increased in the ischemia group, which was reduced markedly by exercise preconditioning (P < 0.05). This study showed that pre-ischemic exercise can exert neuroprotective effects against ischemia in CA3 neurons.

Inhibitory effects of deferasirox on the structure and function of bovine liver catalase: a spectroscopic and theoretical study

Abstract: Deferasirox (DFX), as an oral chelator, is used for treatment of transfusional iron overload. In this study, we have investigated the effects of DFX as an iron chelator, on the function and structu...

Probing of the interaction between β-lactoglobulin and the anticancer drug oxaliplatin.

Abstract: The potential carrier role of β-lactoglobulin (β-LG) and its interactions with oxaliplatin were studied using various spectroscopic techniques (fluorescence, UV-visible, and circular dichroism (CD)) in an aqueous medium at two temperatures of 25 and 37 °C in combination with a molecular docking study. Fluorescence measurements have shown that the observed quenching is a combination of static and dynamic quenching with a predominant contribution of static mode. The presence of a single binding site located in the internal cavity of the β-barrel of β-LG was confirmed by molecular docking calculations. Thermodynamic data as well as molecular docking indicated that the hydrophobic interactions dominate in the binding site. Results of fluorescence resonance energy transfer (FRET) measurements in combination with docking results imply that resonance energy transfer occurs between β-LG and its ligand oxaliplatin. Additionally, CD results revealed that oxaliplatin binding has no influence on the β-LG structure. The molecular docking results indicate that docking may be an appropriate method for the prediction and confirmation of experimental results. Complementary molecular docking results may be useful for the determination of the binding mechanism of proteins such as β-LG in pharmaceutical and biophysical studies providing new insight in the novel pharmacology and new solutions in the formulation of advanced oral drug delivery systems.

Evaluation of groundwater chemistry and its suitability for drinking and agricultural uses in the Lenjanat plain, central Iran

Abstract: Study of the 59 groundwater samples from Lenjanat area, central Iran, was carried out in order to assess their chemical compositions and suitability for drinking and agricultural purposes. Based on Gibbs’ diagram, weathering of rocks and evaporation were found to be the dominant processes in the ion concentration of the water samples. The saturation index calculated through geochemical modeling indicates a suitable chemical environment for anhydrite, aragonite, calcite, dolomite, fluorite, and gypsum dissolution in both wet and dry seasons. All samples have the SO4 2− + HCO3 − more than 5 meq/l indicating that in addition to calcite and dolomite, dissolution of gypsum is the probable process in this plain. Assessment of the concentration of Mg2+ + Ca2+ proportion to SO4 2− + HCO3 − demonstrates that the advanced direct and reverse ion exchange between groundwater and surrounding environment has occurred. The Chadha diagram indicates that the amount of earth-alkali parameters is more than alkali ones and by considering the high value of strong acids, the dominant hydrochemical facies in both wet and dry seasons are Ca2+–Mg2+–Cl−–SO4 2−. According to pollution index, in the selected time domain, all samples are in safe conditions. Calculation of entropy weighted water quality index for groundwater samples demonstrates that in the wet and dry seasons, over 57 and 42 % of the samples are in the range of “excellent” to “medium” quality, respectively. The values of SI, RSC, SSP, SAR, KR, PI, MAR, and CI show that 90 and 85 % of the samples in wet and dry seasons have the good quality for agricultural purposes.

An inventory model for non-instantaneous deteriorating items with partial backlogging, permissible delay in payments, inflation- and selling price-dependent demand and customer returns

Abstract: This paper develops an economic ordering policy model for non-instantaneous deteriorating items with selling price- and inflation-induced demand under the effect of inflation, permissible delay in payments and customer returns. Shortages are allowed and partially backlogged. The customer returns are assumed to increase with both the quantity sold and the product price. The main objective is to determine the optimal selling price, the optimal length of time in which there is no inventory shortage, and the optimal replenishment cycle simultaneously, to minimize the present value of the total profit. An efficient algorithm is presented to find the optimal solution of the developed model. Finally, a numerical example is extracted to solve the presented inventory model using the proposed algorithm.

Optimization of rewards in single machine scheduling in the rewards-driven systems

Abstract: Article history: Received January 20, 2015 Received in revised format 6 February 2015 Accepted 25 March 2015 Available online March 25 2015 The single machine scheduling problem aims at obtaining the best sequence for a set of jobs in a manufacturing system with a single machine. In this paper, we optimize rewards in single machine scheduling in rewards-driven systems such that total reward is maximized while the constraints contains of limitation in total rewards for earliness and learning, independent of earliness and learning and etc. are satisfied. In mentioned systems as for earliness and learning the bonus is awarded to operators, we consider only rewards in mentioned systems and it will not be penalized under any circumstances. Our objective is to optimize total rewards in mentioned system by taking the rewards in the form of quadratic for both learning and earliness. The recently-developed sequential quadratic programming (SQP), is used by solve the problem. Results show that SQP had satisfactory performance in terms of optimum solutions, number of iterations, infeasibility and optimality error. Finally, a sensitivity analysis is performed on the change rate of the objective function obtained based on the change rate of the “amount of earliness for jobs (Ei parameter)”. Growing Science Ltd. All rights reserved. 5 © 201