Semiempirical Study Research Articles

Molecular Docking and Semi-Empirical Study of the Binding between Allura Red, a synthetic food dye, with Bovine Serum Albumin

Molecular Docking and Semi-Empirical Study of the Binding between Allura Red, a synthetic food dye, with Bovine Serum Albumin

Molecular Docking and Semi-Empirical Study of the Binding between Allura Red, a synthetic food dye, with Bovine Serum Albumin

Molecular Docking and Semi-Empirical Study of the Binding between Allura Red, a synthetic food dye, with Bovine Serum Albumin

Molecular Docking and Semi-Empirical Study of the Binding between Allura Red, a synthetic food dye, with Bovine Serum Albumin

Molecular Docking and Semi-Empirical Study of the Binding between Allura Red, a synthetic food dye, with Bovine Serum Albumin

Semiempirical studies, spectral analysis, in vitro antibacterial and DNA degradation studies of heterocyclic thiosemicarbazone ligand and its metal complexes

We have synthesized (Z)-1-(3,3-dimethyl-5-oxocyclohexylidene)-3-(pyridin-2-yl)thiourea (H2DEPT) and their Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Cd(II), Hg(II), Zn(II) and U(VI)O2 complexes. They were characterized using FT-IR, UV–vis 1H NMR, and 13C NMR, magnetic and thermal technique. To interpret the experimental data, theoretical calculations have been performed to obtain IR spectra of ligand and its complexes using AM1, MM, Zindo/1, MM+ and PM3, methods. The combined use of experiments and computations allowed a firm assignment of the majority of observed bands for the compound. The calculated stretching frequencies have been found to be in good agreement with the experimental frequencies. The electronic and charge transfer properties have been explained on the basis of highest occupied molecular orbitals (HOMOs), lowest unoccupied molecular orbitals (LUMOs) and density of states (DOS). The theoretical results showed good agreement with the experimental values. Furthermore, the kinetic and thermodynamic parameters for the different decomposition steps were calculated using the Coats-Redfern and Horowitz-Metzger methods. Finally, the antibacterial results suggest that Cr(III), Mn(II), Cd(II), Fe(III), Ni(II), Zn(II) metal complexes showed potential antibacterial activity. The biochemical studies showed that, all complexes have powerful and complete degradation effect on DNA except H2DEPT and its Zn(II) complex. For the foremost majority of cases the activity of the ligand is greatly enhanced by the presence of a metal ion. Thus presented results may be useful in design new more active or specific structures.

Effect of heterosubstituent and ring puckering angle on linear and nonlinear properties of exo-insaturated four-membered heterocycles, Y=CCH2CH2X: a comparative ab initio, DFT and semi-empirical study

ABSTRACTThe influence of heterosubstituent and ring puckering angle (ϕ) on electronic properties (μ, α, β and γ) of 16 four-membered heterocycles (1–16) were demonstrated theoretically using ab initio (HF and MP2), density functional theory (DFT) (PBE1PBE, SVWN5 and B3LYP) and semi-empirical (PM6 and PM3) treatments. Comparing the DFT and ab initio methods, these showed a similar description of electric dipole moment (μ) and polarisability (α) for each one of the studied heterocycles, with small differences in the prediction of α. The calculated hyperpolarisabilities (β and γ) are very sensitive to the quality of level theory, especially when the heterocycles contain phosphorus and sulphur. On the other hand, comparing with the rest of methods used, the semi-empirical calculations show significant deviations in the prediction of the different properties, and only are in agreement with the calculations of μ for the heterocycles that do not contain phosphorus or sulphur. In general, β and γ are more sensitive to the molecular geometry than μ and α. The dipole moment is determined by the heteroatom (X) within the ring, where the oxetanes and thietanes exhibit a minimum value of μ at planar conformations, while the azetidines and phosphetanes at axial conformations. All heterocycles show a minimum value of α at planar conformation, and their largest values are associated to conformations highly puckered. β exhibits an implicit relationship with the C = Y bond according to the conformational states. In addition, the X and Y heterosubstituents affect significantly the values of α, β and γ, observing the largest values for the phosphorus- and sulphur-containing heterocycles. Finally, considering the values obtained for α, β and γ, the studied heterocycles can represent an interesting unit for the design of new promising push–pull systems as donor or acceptor group.

Effect of Vitamin C on Serum Concentration of Brain-Derived Neurotrophic Factor among Healthy Inactive Young Men

Introduction: The aim of this study was to investigate the effect of consuming vitamin C on the serum level of Brain-derived neurotrophic factor (BDNF) among healthy inactive young men. Materials and Methods: In this semi-empirical study, 18 healthy inactive men were randomly divided into two groups; a group consuming vitamin C as a supplement and a control group. Subjects in consuming vitamin C group received 500 milligrams of vitamin C supplement daily for one week. The control group consumed placebo. Blood samples of participants were taken in fasting mode to measure BDNF concentration. BDNF was measured by ELISA method. Results: The serum levels of BDNF significantly increased one week after receiving vitamin C compared to the control group. In addition, the level of BDNF in subjects received vitamin C for one week significantly increased compared to the beginning of the investigation. Conclusion: Data indicate that consuming vitamin C increased the serum concentration of BDNF in healthy inactive men.

THE DISCUSSION ON THE EFFECTS OF PULMONARY REHABILITATION PROGRAM ON QUALITY OF LIFE FOR PEOPLE WITH CHRONIC OBSTRUCTIVE PULMONARY DISEASE

Chronic obstructive pulmonary disease is a disease that is determined by airflow limitation in the lungs. So that this limitation is not fully reversible. The aim of this study is to determine the effect of rehabilitation program on quality of life in patients with chronic obstructive pulmonary disease. In this semi-empirical study, 90 persons of individuals with this disease were selected by sampling and divided to two experimental and control and finally 33 persons and 37 persons remain of witness group and test group respectively. Data collection tools included demographic information questionnaire and discussion of quality of life. The results have shown that pulmonary rehabilitation program leads to improvement of patients’ quality of life and there is a meaningful relationship between some of the demographic characteristics of patients and their quality of life score as well.

Semi-Empirical Study of the Indirect Exchange Interaction in the Rem – Al System

The Ruderman–Kittel–Kasuya–Yosida exchange interaction (RKKY) is semi-empirically studied for the first time in compounds of binary REM – Al systems (REM – rare-earth metals: Gd, Dy, Ho, Er) using experimental values of paramagnetic Curie point (θр) of these compounds. Prediction of the RKKY theory was confirmed, i.e. there is a direct proportional dependence of θр value on de Gennes factor for equiatomic compounds of heavy REM with aluminum, just as in the case of pure REM. Values of the indirect exchange interaction parameter were semi-empirically estimated for the studied compounds. In general, it was established that RKKY-type exchange interaction is typical for REM compounds with aluminum, just as for pure REM.

Preparation and characterization of a imipramine-ß-cyclodextrin inclusion complex

ABSTRACTThis article characterizes the association between imipramine and ß-cyclodextrin. The formation of supramolecular host-guest inclusion complex of imipramine with the nano-hydrophobic cavity of ß-cyclodextrin was prepared by physical mixing and coprecipitation. The inclusion complex of imipramine and ß-cyclodextrin in solution was characterized by ultraviolet-visible and fluorescence spectroscopy. The inclusion complex was characterized by infrared spectroscopy, scanning electron microscopy, X-ray diffraction, thermogravimetric analysis, and differential scanning calorimetry. The spectral shifts showed that only a portion of the imipramine molecule was within the ß-cyclodextrin cavity. The binding constant and the 1:1 stoichiometry of the inclusion complex at 303 K was obtained using a Benesi-Hildebrand plot. The Gibbs free energy change of the complex formation process was determined and the complex formation was shown to be spontaneous. The changes observed in vibrational frequencies, morphology, diffraction, and thermal stability confirmed the formation of the solid inclusion complex. Molecular docking and semi-empirical studies were used to characterize the ß-cyclodextrin-associated inclusion complexes of imipramine. The results of molecular modeling were systematically analyzed to determine the stability of the complexes.

Electronic Structures of Anti-Ferromagnetic Tetraradicals: Ab Initio and Semi-Empirical Studies.

The energy relationships and electronic structures of the lowest-lying spin states in several anti-ferromagnetic tetraradical model systems are studied with high-level ab initio and semi-empirical methods. The Full-CI method (FCI), the complete active space second-order perturbation theory (CASPT2), and the n-electron valence state perturbation theory (NEVPT2) are employed to obtain reference results. By comparing the energy relationships predicted from the Heisenberg and Hubbard models with ab initio benchmarks, the accuracy of the widely used Heisenberg model for anti-ferromagnetic spin-coupling in low-spin polyradicals is cautiously tested in this work. It is found that the strength of electron correlation (|U/t|) concerning anti-ferromagnetically coupled radical centers could range widely from strong to moderate correlation regimes and could become another degree of freedom besides the spin multiplicity. Accordingly, the Heisenberg-type model works well in the regime of strong correlation, which reproduces well the energy relationships along with the wave functions of all the spin states. In moderately spin-correlated tetraradicals, the results of the prototype Heisenberg model deviate severely from those of multi-reference electron correlation ab initio methods, while the extended Heisenberg model, containing four-body terms, can introduce reasonable corrections and maintains its accuracy in this condition. In the weak correlation regime, both the prototype Heisenberg model and its extended forms containing higher-order correction terms will encounter difficulties. Meanwhile, the Hubbard model shows balanced accuracy from strong to weak correlation cases and can reproduce qualitatively correct electronic structures, which makes it more suitable for the study of anti-ferromagnetic coupling in polyradical systems.

Optimization of Hydrogen Storage Capacity by Physical Adsorption on Open-ended Single-walled Carbon Nanotube as Diameter Function

In this paper, we perform combination methods of semi-empirical research, a theoretical approach, and force-matching to determine the optimum adsorption capacity on an open-ended single-walled carbon nanotube (SWCNT) as a diameter function. Using a semi-empirical study, we can determine the value of monolayer coverage and isosteric heat of adsorption from available thermodynamic data. By completing the semi-empirical study, we carried out quantum mechanical calculations to determine the adsorption energy on the interior and exterior of SWCNTs. Furthermore, monolayer coverage, specific surface area, and maximum adsorption capacity as the main quantity in the adsorption process was estimated using the combination method of force-matching and a classical Lennard-Jones potential model. Hydrogen physisorption was investigated on zig-zag SWCNTs at conditions for a pressure range of 0.1 to 10 MPa at 233 K and 298.15 K temperature. The adsorption of all data can be explained with the Toth model. The results shows the SWCNT exterior physisorption energy range between 1.35 to 1.62 kcal/mol. The interior range from 1.22 to 2.43 kcal/mol. With a wide degree of temperature and pressure variations, we obtained an optimum SWCNT diameter of 8-12 A . At the optimum diameter maximum adsorption capacity, we achieved 1.75 wt% at 233 K and an operating pressure of 10 MPa.

Comparison of Electronic and Workshop Teaching Methods on Midwives Knowledge about Pregnant Women Caring and Attitude Regarding to E-Learning in Kerman

Introduction Obstetricians and health personnel are the first and foremost personnel with direct patient contact. E-learning can be considered an appropriate method for the in-service training of the health personnel. Therefore, the present study was conducted aiming at an investigation on the efficacy of the two training methods of workshop and e-learning training on the level of knowledge of the obstetricians as well as their attitudes towards e-Learning. Methods This was a semi empirical study in which 66 obstetricians, working at health centers. The participants were randomly divided into two groups of workshop (33 subjects) and e-Learning training (33 subjects). Using knowledge and attitude questionnaire, the knowledge and attitude of the subjects in the two groups were measured and data was analyzed through paired and independent T-test employing SPSS version 18. Results No difference was observed between the knowledge pre-test scores of the two groups; and the post-test scores of the two groups showed an identical and significant increase. Furthermore, the difference between scores of attitude towards e-learning, before and after training (34.24 ± 4.86 and 36.76 ± 6.36, respectively) was statistically significant (P = 0.04). Conclusions The results showed that both training methods increased the personnel knowledge level equally and that the attitudes of participants of the e-learning training group were more positive towards e-learning subsequent to the training. As a result, e-learning training method (especially in the form of training CDs) can be employed as a complement to workshop training and a modern method to be adopted for employee in-service training.

The Effect of Group-Discussion on the Nurses' Performance of Patients' Rights

Objective : Group discussion enhances the knowledge and the quality of cares provided for patients and reinforces nurses' skills and diagnostic reasoning, its effect on changing and respecting patients' right has though been less considered. This paper, thus, aims to study the effect of group discussion on nurses' performance in respecting the rights of patients staying inMadaniHospital inTabrizIran in 2014. Methods : This is a semi-empirical research study conducted on nurses using a pre- and post-test design. A research sample of 71 nurses randomly selected with negative attitude scores or less than 80 on respecting patients' rights. Data were gathered by an observation checklist including the principle components of patients' physical, mental and social rights. Data were analyzed in SPSS. Results : Mac Nemar Test was used to compare results before and after intervention. Results indicated that there was a significant statistical difference in the group on respecting patients' rights (p < 0.05). Conclusion : According to results, group discussion may contribute to the improvement of nurses' performance in respecting and understanding patients' rights. Group discussion is recommended to be held as an appropriate method in educational therapy centers to improve nurses' perception of patients' rights

SYNTHESES AND CHARACTERIZATIONS OF COPPER COMPLEXES: INTERACTION OF COPPER ACETATE DIHYDRATE WITH 4,4´-BIPYRIDINE

ABSTRACT Two complexes have been synthesized through the reaction of copper(II) acetate dihydrate with 4,4´-bipyridine. Both were characterized by elemental analysis, magnetic moment, FT-IR spectroscopy, and thermogravimetric analysis. Semiempirical structural DFT studies of [Cu 2 (CH 3 COO) 4 (4,4.bipy) 2 ] n and 4,4´ bipyridine were carried out.4,4´-Bipyridine acts as bidentate ligand, breaking the Cu 2 (CH 3 COO) 4 unit and acting as bridge between the metal centers, yielding a polymeric structure bearing monodentate acetate groups. The compounds [Cu 2 (CH 3 COO) 4 (4,4-bipy) 2 ] n and [Cu 2 (CH 3 COO) 4 (4,4-bipy) 2 (H 2 O) 2 ] n have magnetic moments of 1.83 and 1.77 B.M, respectively. These values are higher than those of copper (II) acetate monohydrate (1.4 B.M). Keywords: metallic acetates, 4,4´-bipyridine, DFT calculations. INTRODUCTION Metal complexes with carboxylates and nitrogen ligand are the subject of particular interest due to their biochemical importance. Several studies of copper(II) acetate complexes with nitrogen ligands, such as pyridine, aminopyrimidine, bipyridyl, and nicotinamide, have been reported. Instead of forcing dissociation of the dinuclearCu

Synthesis, Spectroscopy, Semi‐empirical and Biological Activities of Organotin(IV) Complexes with o‐Isopropyl Carbonodithioic Acid

AbstractNew organotin(IV) complexes have been synthesized by treating potassium o‐isopropyl carbonodithioate with R2SnCl2/R3SnCl in 1 : 2/1 : 1 M/L ratio. All complexes have been characterized by IR and NMR (1H, 13C) spectroscopy. IR results shows that ligand acts as bidentate which is also confirmed by semi‐empirical study. NMR data reveals four coordinated geometry in solution. Computed positive heat of formation shows that complex 5 is thermodynamically unstable. UV/visible spectroscopy was used to assess the mode of interaction and binding of the complexes with DNA which shows that complex 5 exhibits higher binding constant as compared to complex 3. In protein kinase inhibition assay, compound 3 was found most active, while other biological activities shows that triorganotin(IV) complexes are biologically more active as compared to diorganotin(IV) complexes.

EFFECTIVENESS OF E-LEARNING COMPARED TO CLASSROOM LEARNING IN THE DIAGNOSTIC APPROACH TO BIOTERRORISM AND CHEMICAL TERRORISM FOR EMERGENCY PHYSICIANS

Background and purpose: Emergency physicians play an important role in the immediate diagnosis of bioterrorism activities. The present study was conducted with the purpose of comparing the effectiveness of e-learning and classroom learning in approach to bioterrorism and chemical terrorism for emergency physicians. Methods: This was a semi-empirical study, which was conducted via testing knowledge before and after the educational intervention in the field of bioterrorism and chemical terrorism on the emergency physicians in Tehran. The external validity of the questionnaire was confirmed by two academic experts in order to determine the ability to detect bioterrorist and chemical terrorist diseases. In this study, education was done in both virtual and classroom forms. The education regarded 6 bioterrorist diseases in group A (anthrax, plague, viral hemorrhagic fever, tularemia, smallpox), and 5 chemical terrorist diseases (nerve gas, mustard, lewisite, phosgene, chlorine). Results: 160 doctors participated in this study. 96 people (60%) were men and 64 people (40%) were women. The average age of the participants was 36.2±5.5 years. In e-learning method, the pre-test scores average was (30.6%), while the post-test scores average was (81.6%) (p=0.001). In classroom learning method, the pre-test scores average was (41.9%), while the post-test scores average was (72.9%), which the pre-test and post-test scores average differences in both cases are significant (p<0.001). In e-learning method, the difference was (51%), and in the classroom method it was (31%), which these two represent a 20% difference between methods. From statistical point of view, this difference indicates that the e-learning method being more effective (p=0.02). Conclusions: Based on the study results, it seems that in comparison to the classroom learning, e-learning method is more effective in helping emergency physicians to diagnose bioterrorism or chemical terrorism factors. Keywords: E-LEARNING, CLASSROOM LEARNING, CHEMICAL TERRORISM, BIOTERRORISM, EMERGENCY PHYSICIANS

Zn and Pb marking of Ca binding to humic substances and PHREEQC speciation simulations

Power generating companies using and recycling cooling water usually experience deposition of insoluble salts on pipes carrying the water, leading to scaling problems. By controlling parameters that optimize competitive Ca complexation, the scaling potential could be reduced. This semi-empirical study determined the effect of ligands in binding, as well as the optimum parameters for Ca complexation experimentally using simulated water solutions before modelling. Experimental results showed that metal binding to ligands depended on the type of metal in competition, the pH and the humic substance used. Zn and Pb voltammetric peaks decreased with the addition of humic acid, tannic acid and catechol. Ca showed a synergistic phenomenon in the form of increased peak heights of the trace cations. Using PHREEQC model saturation index output results, the mineral phases likely to precipitate were successfully described. Furthermore, the effect of changing pH on scale formation was determined. For example, we successfully described the influence of pH on speciation and complexation through the formation of H-humate− and humate2−. The models showed that pH may be manipulated to govern the incidence of scale. Predictive models were derived to determine what would be a useful tool in reducing the potential for scaling.

Synthesis, spectral, DFT, and semi-empirical study of trimetallic complexes with pyrazole-3,5-dicarboxylic acid containing Sn(IV) and Hg(II)

Trimetallic compounds have been synthesized by treating pyrazole-3,5-dicarboxylic acid with CS2, di-, and triorganotin(IV) chlorides and HgCl2 under reflux. The complexes have been characterized by elemental analysis, IR, 1H and 13C NMR spectroscopy. Dipole moments and charges were calculated by the semi-empirical method. Two complexes were studied by DFT (BLYP/3-21G, B3LYP-3-21G) and semiempirical methods (PM3, PM6, MNDO, AM1, ab initio). IR data indicated that Sn was attached to oxygen of the carboxylic groups in a bidentate manner and adopted trigonal bipyramidal geometry. Hg was bonded to both S atoms of a ligand and exhibited square planner geometry in solid state. NMR data confirmed the four coordinated geometry of compounds in solutions.

Surface characterization and sorption efficacy of tire‐obtained carbon: experimental and semiempirical study of rhodamine B adsorption

This work focuses on the surface characterization and sorption activity of carbon derived from waste tires. The carbon was prepared by thermal treatment of waste rubber tires, followed by exposure to nitric acid and hydrogen peroxide. The tired‐obtained activated carbon (AC) was evaluated using a variety of techniques. Fourier transform infrared spectroscope and Raman spectra reveal existence of hydroxyl and carboxylic groups on AC surface. Scanning electron microscope and Brunauer–Emmett–Teller revealed the porosity of AC is well developed with mesopore structure (mesopore volume of 0.96 cm3/g). AC was tested for Rhodamine B sorption, and the adsorption kinetics well fitted using a pseudo second‐order kinetic model. The adsorption isotherm data could be well described by the Langmuir model. Semiempirical calculations using Austin Model 1 were performed to explain the adsorption at molecular level. Binding enthalpies in the range of 0.5–4 kcal/mol of four possible scenarios were computed. We believe the combination between experimental work and semiempirical calculations allows for a better understanding of Rhodamine B molecules adsorption on the AC surface. Copyright © 2015 John Wiley &amp; Sons, Ltd.

Synthesis and characterization of hetero-bimetallic complexes with 2-mercapto-5-methyl-benzimidazole: theoretical study and biological activities

Heterobimetallic complexes have been synthesized by stirring 2-mercapto-5-methylbenzimidazole with carbon disulfide in methanol at room temperature. In the second step, the product was treated with R2SnCl2/R3SnCl (R = Me, n-Bu, Ph) in 1 : 1 M ratio, then organotin(IV) complexes were treated with HgCl2 in 2 : 1 M : L ratio to yield heterobimetallic complexes. The ligand and complexes have been characterized by elemental analysis, IR, 1H- and 13C NMR spectroscopy, mass spectrometry (EI-MS), and semiempirical study to assess the binding mode of the heterobimetallic complexes. IR data showed the bidentate nature of the dithiocarbamate moiety, which is also confirmed by semiempirical study. Mass spectra correspond to the expected for the complexes. NMR spectroscopy confirmed the four-coordinate geometry in solution. Computed molecular descriptors, thermodynamic parameters, and electrostatic surface potential map of 4 were calculated by using the PM6 method. Biological screening data indicated that complexes exhibit significant activity against various bacterial and fungal strains with few exceptions. Ligand and 6 are excellent for phagocyte reactive oxygen species inhibition.