zahra fallah ebrahimi

A comparative ab initio study is performed to investigate the cooperativity between the N···H hydrogen bond and the N···Y interactions in XCN···HCN···YCN complexes, where X = H, F, and Y = H, Li, F, Cl, and Br. To understand the properties of the systems better, the corresponding dimers are also studied. It is found that the lithium bond has a larger influence on the hydrogen bond than vice versa. The shortening of the N···H distances in the trimers is dependent on the strength of the H···Y interactions and they become larger in the order lithium bond > hydrogen bond > halogen bond. The estimated values of cooperative energy Ecoop are all negative with much larger Ecoop in absolute value for the systems including lithium.

Small and Medium-sized Enterprises (SMEs) are comprised 90% of all enterprises in Iran. In this regards they have significant role in the development of the country's economy. The purpose of this paper is to develop a conceptual framework to investigate the impact of multidimensionality of total quality management practices on the role stressors. Numerous studies have been done by other researchers on the quality revolution and implemented various Total Quality Management (TQM) programs such as ISO 9000 series as a way to improve quality. This paper investigates the multidimensional relationships between eight TQM practices and role stressors. The empirical data was gathered from 410 Iranian manufacturing SMEs and analysed by using the Structural Equation Modelling (SEM) technique. The findings indicate important association among leadership, information analysis; supplier management, employee involvement, process management and human resources focus with role stressors but no significant relationship between customer focus and supplier management with role stressors.

Studies have demonstrated the efficacy of metformin (MTF ) in reducing insulin resistance and N-acetyl cysteine (NAC) in inhibiting oxidative stress which are involved in the pathogenesis of polycystic ovarian syndrome (PCOS). We aimed to compare the effects of MTF and NAC combination on serum metabolite and hormonal levels during the course of ovulation induction in PCOS individual candidates of intracytoplasmic sperm injection (ICSI). In this prospective randomized clinical trial, placebo con- trolled pilot study, 80 patients of polycystic ovarian syndrome at the age of 25-35 years were divided into 4 groups (n=20): i. NAC=treated with N-acetyl cysteine (600 mg three times daily), ii. MTF=treated with metformin (500 mg three times daily), iii. MTF+NAC=treated with N-acetyl cysteine plus metformin (the offered doses) and iv. placebo (PLA). A total number of 20 patients (6 from MTF group, 4 from NAC group, 6 from MTF+NAC group and 4 from PLA group) were dropped of the study. The dru...

Killer cell immunoglobulin-like receptors (KIR) gene frequencies vary between populations and contribute to functional variation in immune responses to viruses, autoimmunity and reproductive success. This study describes the frequency distribution of 12 variable KIR genes and their HLA-C ligands in two Iranian populations who have lived for many generations in different environments: the Azerbaijanis at high altitude and the Jonobi

The aim of this study was to analyse the explanatory power of variables measuring health-strengthening factors for self-rated health among community-living frail older people. Frailty is commonly constructed as a multi-dimensional geriatric syndrome ascribed to the multi-system deterioration of the reserve capacity in older age. Frailty in older people is associated with decreased physical and psychological well-being. However, knowledge about the experiences of health in frail older people is still limited. The design of the study was cross-sectional. The data were collected between October 2008 and November 2010 through face-to-face structured interviews with older people aged 65-96 years (N = 161). Binary logistic regression was used to analyse whether a set of explanatory relevant variables is associated with self-rated health. The results from the final model showed that satisfaction with one's ability to take care of oneself, having 10 or fewer symptoms and not feeling lonely had the best explanatory power for community-living frail older peoples' experiences of good health. The results indicate that a multi-disciplinary approach is desirable, where the focus should not only be on medical problems but also on providing supportive services to older people to maintain their independence and experiences of health despite frailty.

In this study we explored frail elders' experiences with and perceptions of the phenomenon of health so as to develop a deeper understanding of living with diseases and disorders in old age. Frail elders participated in qualitative interviews that explored the meaning of the phenomenon of health for them. Eleven men and 11 women, who had diverse ratings of self-perceived health ranging from poor to excellent, were selected by means of a purposeful strategic sampling of frail elders taken from a broader sample that participated in a larger quantitative study on health. In total, 22 individual interviews were analyzed using Giorgi's descriptive phenomenology. We found that frail elders described health as being in harmony and balance in everyday life, and this occurred when participants were able to adjust to the demands of their daily lives in the context of their resources and capabilities.

The purpose of this study is to develop a conceptual model to examine the multidimensionality of total quality management (TQM) practices and their impact on role stressors. The background of TQM and role stressors theories are considered the beginning-points for the development of the conceptual model. The model is based on TQM practices, and by considering the role of stressors, a basis for an evaluation of the level of role stressors under which the employment and retention of different parts of TQM should be revised is established. The finding proposes the TQM practices that will have a greater effect on role stressors components. For this analysis, the proposed model is a useful tool for practical contributions to study because it includes independent TQM practices regarding role stressors, and organisational administrators can achieve a view of the negative and positive influences of TQM practices on employees' role stressors. The conceptual model presents a full view of the relationship between the multidimensionality of TQM and the role stressors. The model evaluates the dependent function of role stressors toward TQM practices as the independent variables.

Human resource plays a critical role in the success or failure of any decision to take a publicly traded company private. Also, it plays more of a transformational role in helping the organization in identifying and meeting the larger challenges it faces in its external environment by ensuring that the internal mechanisms that facilitate change are in place. People are an organization's only sustainable competitive advantage. For these reasons, the main objective of this study was to investigate the situation human resource practices in Teaman Company (Refah Tea). This study showed that human resource is process to achieve the right people in the right job at the right time. It will do is make an assessment of the current capabilities of employees, determine what it will need in the future, and design a program to meet those needs. With considering objectives and strategies, demand for human resources is contingent upon demand for products.

This paper considers the problem of choosing optimal production policy in an integrated production-inventory system comprising a single manufacturer and a single buyer. Two production scenarios are compared, namely continuous and lot-for-lot production policies, using a mathematical modelling approach and the expected total joint cost is considered as the performance measure. In addition, the lost opportunity cost due to production downtime in the lot-for-lot policy, including the cost of unemployment of human resources and stoppage of the production line, is incorporated into the model. Numerical experiment and sensitivity analysis in terms of setup and lost opportunity costs are provided to illustrate the theory and the percentage of difference in the expected total cost of the two policies is analysed. The presented approach helps managers to make the right decisions on the optimal production policy under different conditions, especially where expert and technical human resources and/or expensive production equipments are utilised. Keywords: joint economic lot size model; single-vendor single-buyer; SVSB; continuous production policy; lot-for-lot production policy; integrated system; lost opportunity cost. 2 R.H. Rad et al. Reference to this paper should be made as follows: Rad, R.H., Razmi, J., Sangari, M.S. and Ebrahimi, Z.F. (xxxx) 'A note on the joint economic lot size model with stochastic demand and variable lead time', Int.

This paper considers a two-echelon supply chain model with a single vendor and two buyers in which the vendor supplies the same item to both buyers at a finite production rate. The purpose of this study is twofold. First, mathematical models are developed for the integrated vendor-managed inventory (VMI) policy as well as the traditional retailer-managed inventory (RMI) system and solution algorithms are presented to determine the optimal lot size and total inventory cost of the supply chain. Then, the effect of key parameters including buyer's demand, buyer's transportation cost, vendor's ordering cost, and vendor's holding cost on lot size variation is studied in each policy. A weighting factor is also determined for the vendor's ordering cost which is used to compare the two policies. Detailed numerical experiments are provided to illustrate efficacy of the proposed approach. Results indicate that greater reduction in total cost of supply chain can be achieved by using VMI and provide a comprehensive insight into selection of inventory policies to improve commercial business and supply chain performance.

Purpose – The aim of this paper is to evaluate the impact of total quality management (TQM) practices on role stressors in Iranian manufacturing SMEs in order to determine the relationship between the multidimensionality of TQM practices and role ambiguity, role conflict and role overload. Design/methodology/approach – Questionnaires are administrated to 410 employees of 100 different manufacturing SMEs in Iran. Findings – The results support important negative association among some of TQM practices (such as employee involvement, information analysis, process management, supplier management, strategic planning and customer focus) and role conflict, role ambiguity, role overload. By utilizing multiple regression analysis, information analysis, supplier management, employee involvement, process management, customer focus, strategic planning are found to have significant and negative relationship with role stressors. Leadership and human resource focus are found to have significant and positive relationship with role stressors. Practical implications – This model is perfect for practical usage by SME managers to estimate the perceptions of role stressors of employees in TQM oriented firms. The findings recommend that manufacturing should look into ways of improving the major roles of TQM practices in order to decrease the negative role stressors of employees. Originality/value – TQM practices emerge to be related to role stressors (role ambiguity, role conflict and role overload), attending to an obvious noticeable gap in the previous studies of TQM and the psychological welfare of employees.

In this study, by carrying out detailed density functional theory calculations, we investigate the adsorption and stepwise decomposition of hydrogen peroxide (H 2 O 2) over (6,0) and (7,0) zigzag silicon carbide nanotubes (SiCNTs). The results indicate that the H 2 O 2 can be adsorbed on the exterior surface of the SiCNTs with noticeable adsorption energies and charge transfers. To gain insight into the catalytic activity of the surface , the interaction between the H 2 O 2 and SiCNT is analyzed by detailed electronic analysis such as adsorption energy, charge density difference and activation barrier. The decomposition of H 2 O 2 into O 2 and H 2 species can be viewed as the kinetically preferred reaction pathway for dehydrogenation of hydrogen peroxide over SiCNTs. There is also a curvature effect on the dehydrogenation kinetics of hydrogen peroxide, that small diameter SiCNTs with large curvature would be beneficial for decomposition of H 2 O 2. V

Computational studies have been carried out at DFT-B3LYP/ 6-31+G* and PW91P86/6-31+G* levels of theory on the structural and spectroscopic properties of 3,4-methylenedioxymethamphetamine (MDMA) and its derivatives. Nuclear quadrupole coupling constants (NQCCs) of 14 N and 17 O and chemical shift of 13 C and 1 H have been calculated. There is a good correlation between the calculated chemical shifts of 13 C and 1 H and experimental data. Our results showed that 14 N and 17 O NQCCs are quite sensitive to substitute-induced structural charge. In these compounds, a correlation has been observed between the parameters characteristic biological activity (LD50, IC50) and nuclear quadruple resonance (NQR) parameters. We also report a computational study for the 14 N and 17 O nuclear magnetic resonance (NMR) tensors in ecstasy and its derivatives. To our knowledge, no sufficient ab initio study has been carried out on MDMA and its derivatives. Reference to this paper should be made as follows: Ebrahimi, Z.F. (2016) 'An ab initio study on 3,4-methylenedioxymethamphetamine, MDMA (ecstasy) and its derivatives', Int.

To understand the relationship between the electronic structure of amphetamines and their biological activity, a computational investigation was carried out to characterise the 17 O and 14 N, electric field gradient (EFG) tensors and nuclear quadrupole coupling constants (NQCC) as well as 17 O, 15 N, 13 C and 1 H chemical shielding tensors of amphetamines. Calculation were performed with the B3LYP and PW91P86 density functional theory (DFT) methods with the 6-311++G(d,p) basis set. The anisotropic (∆σ) and isotropic (σ iso) shielding are in good agreement with the available experimental data. The results indicate that the EFG and σ at oxygen are insensitive to substitution at the N and C 10 positions in amphetamines. In contrast, the nitrogen EFG and σ are quite sensitive towards substituent changes. Furthermore, it was found that EFG tensors are more sensitive than σ tensor to the electron density distribution in amphetamines. Biological activities of amphetamines were found to depend upon the electron density distribution in the region of N atoms. Reference to this paper should be made as follows: Ebrahimi, Z.F. and Wilson, D.J.D. (2015) 'DFT investigation of the electronic structure of amphetamines: effect of substituent on O and N chemical shielding and electric field gradient tensors', Int.