Showing papers by "Islamic Azad University North Tehran Branch published in 2008"

Density functional calculations of oxygen, nitrogen and hydrogen electric field gradient and chemical shielding tensors to study hydrogen bonding properties of peptide group (OC–NH) in crystalline acetamide

Abstract: A density functional theory (DFT) study was carried out to investigate hydrogen bonding (HB) properties of peptide group (O C–NH) in crystalline acetamide. Since the peptide group in acetamide contributes to N–H⋯O and C–H⋯O types of HB interactions, acetamide is considered as the simplest form of peptide linkage in proteins. The evaluated NMR parameters including quadrupole coupling constants and asymmetry parameters from the calculated electric field gradient (EFG) tensors at the sites of O17, N14 and H2 nuclei and isotropic chemical shieldings from the calculated chemical shielding (CS) tensors at the sites of O17, N15 and H1 nuclei reveal the major contribution of O C–NH group to HB interactions. Although N–H⋯O type of HB interaction play the major role in the HB properties of peptide group in lattice form of crystalline acetamide, however, the role of weaker C–H⋯O type of HB interaction cannot be neglected.

Trichlorido(4,4'-dimethyl-2,2'-bipyridine-κN,N')(dimethyl sulfoxide-κO)indium(III).

Abstract: In the mol­ecule of the title compound, [InCl3(C12H12N2)(C2H6OS)], the InIII atom is six-coordinated in a distorted octa­hedral configuration by two N atoms from the chelating 4,4′-dimethyl-2,2′-bipyridine ligand, one O atom from dimethyl sulfoxide and three Cl atoms. In the crystal structure, inter­molecular C—H⋯Cl hydrogen bonds link the mol­ecules into centrosymmetric dimers.

(5,5′-Dimethyl-2,2′-bipyridine-κ2N,N′)diiodidomercury(II)

Abstract: In the mol­ecule of the title compound, [HgI2(C12H12N2)], the HgII atom is four-coordinated in a distorted tetra­hedral configuration by two N atoms from 5,5′-dimethyl-2,2′-bipyridine and two I atoms. There is a π–π contact between pyridine rings of adjacent molecules [centroid–centroid distance = 3.723 (5) A].

Audiotaped Dialogue Journal: A Technique to Improve Speaking Skill of Iranian EFL Learners

Abstract: This study attempted to investigate whether there was any significant difference between the speaking achievement of learners who were trained by means of audiotaped dialogue journal, dialogue journal writing, or traditional free speech. The participants, 45 male and female students aged between 21 and 32, were selected by random sampling from among free speech classes in an English teaching Institute in Tehran. On the basis of the scores obtained from an oral interview, a one way analysis of variance (ANOVA) was performed, and it was proved that the three groups were homogeneous in terms of their speaking ability. Yet, the ANOVA performed on the scores of the learners after the treatment showed that the oral proficiency of the three groups differed significantly. A follow-up Tukey test revealed that the audiotaped dialogue journal group did not have any advantage over the dialogue journal writing group, whereas there was a statistically significant difference between the audiotaped dialogue journal group and the traditional free speech group.

Chemical composition and antibacterial activity of essential oils from leaves, stems, and flowers of Salvia reuterana grown in Iran

Abstract: akbaresmaeili@yahoo.com; 2) Marine Science and Technology, North Tehran Branch, I. A. University, Tehran, Iran; 3) Department of Chemistry, Science & Research Campus, I.A. Universiy, O.Box 14515-775 Tehran, Iran; 4) Department of Agronomy, Faculty of Agriculture, Ferdowsi University of Mashhad, Iran; 5) Department of Biology, Islamic Azad University, North Tehran Branch, Tehran, Iran. Published in Khimiya Prirodnykh Soedinenii, No. 3, pp. 313-314, May-June, 2008. Original article submitted January 30, 2007.

Light requirement for the carotenoids production by mucor hiemalis

Abstract: Objective Fungi produce many different carotenoids and some are attractive in medical and industrial sources. In this work the ability of Mucor hiemalis (PTCC 5292) to produce carotenoids in media with different nitrogenous and carbon sources and incubation with white, yellow, blue and red lights (15W, 220V, E27) against dark-grown were studied. Materials and Method The microorganism cultivation in SDA medium, with or without aeration (120 rpm) at 25 °C. Mycelia were collected and dried at 50 °C. The dried mycelia were homogenized in hexane, acetone and H2SO4 (0.5 M) solvents. The carotenoids determined by TLC and HPLC methods. Results Theresults showed that M. hiemalis accumulated astaxanthin (mono-esters, di-esters and free), echinenone and canthaxanthin in the mycelia in different conditions. Blue and white lights incubation was the best for production of carotenoid pigments with 1.2 and 1.33 mg/g dried mycelia respectively, but the red light incubation not only did not have an amplifying effect on the production of carotenoid but also slightly reduced this effect. Also, the effect of intervention of lactose sugar showed more effectiveness in producing carotenoid than yeast extract and dextrose or in the presence of both of them. Conclusion The information reported in this study on the comparative ability of M. hiemalis for producing carotenoids, should be useful for assessing the biotechnological production of carotenoid pigments if it incubates with white or blue lights.

Comparative Critical Reading Strategy and Writing Achievement of Iranian EFL Learners

Abstract: The present study was undertaken to investigate the impact of comparative critical reading strategy on the writing ability of Iranian learners who were learning English as a foreign language (EFL). In order to carry on the study, 60 participants (25 males and 35 females aged between 19 to 27) at intermediate level of language proficiency were randomly assigned to two groups; that is, the experimental and control groups. The participants in the experimental group experienced critical reading by comparing texts, whereas the members of the control group practiced reading texts in the traditional way and answered comprehension questions. The results of the comparisons between the means of the two groups through t-tests proved that practicing comparative critical reading strategy had a significant effect on the improvement of the writing ability of the experimental group. However, the comparison between the means showed no significant difference in the reading ability of the two groups.

2,6-Diamino-pyridinium bis-(4-hydroxy-pyridine-2,6-dicarboxyl-ato-κO,N,O)chromate(III) dihydrate.

Abstract: The reaction of chromium(III) nitrate hexa­hydrate, pyridine-2,6-diamine and 4-hydroxy­pyridine-2,6-dicarboxylic acid in a 1:2:2 molar ratio in aqueous solution resulted in the formation of the title compound, (C5H8N3)[Cr(C7H3NO5)2]·2H2O or (pydaH)[Cr(hypydc)2]·2H2O (where pyda is pyridine-2,6-diamine and hypydcH2 is 4-hydroxy­pyridine-2,6-dicarboxylic acid). Each CrIII atom is hexa­coordinated by four O and two N atoms from two (hypydc)2− fragments, which act as tridentate ligands, in a distorted octa­hedral geometry. The O—Cr—O—C torsion angles between the two planes of the (hypydc)2− fragments [−99.81 (17) and 97.77 (17)°] indicate that these two units are almost perpendicular to one another. In the crystal structure, extensive O—H⋯O, N—H⋯O and C—H⋯O hydrogen bonds with D⋯A distances ranging from 2.560 (2) to 3.279 (3) A, ion pairing, C—O⋯π [O⋯π = 3.166 (2) A] and π–π stacking inter­actions between (hypydc)2− and (pydaH)+ rings [with a centroid–centroid distance of 3.3353 (14) A] contribute to the formation of a three-dimensional supra­molecular structure.

Propane-1,3-diammonium bis-[aqua-chlorido(4-hydroxy-pyridine-2,6-di-carboxyl-ato-κO,N,O)mercurate(II)] tetra-hydrate.

Abstract: The reaction of mercury(II) chloride dihydrate, propane-1,3-diamine and 4-hydroxy­pyridine-2,6-dicarboxylic acid in a 1:1:1 molar ratio in aqueous solution, resulted in the formation of the title compound, (C3H12N2)[Hg(C7H3NO5)Cl(H2O)]2·4H2O or (pnH2)[Hg(hypydc)Cl(H2O)]2·4H2O (where pn is propane-1,3-diamine and hypydcH2 is 4-hydroxy­pyridine-2,6-dicarboxylic acid). The metal atom is coordinated by one chloride group, one water mol­ecule cis to the chloride ligand and one (hypydc)2− ligand. The coordinated water mol­ecule is almost perpendicular to the plane of the aromatic ring of (hypydc)2−. The geometry of the resulting HgClNO3 coordination can be described as distorted square-pyramidal. This structure also contains propane-1,3-diammonium (site symmetry 2) as a counter-ion and four uncoordinated water mol­ecules. There is a wide range of non-covalent inter­actions consisting of hydrogen bonding [of the types O—H⋯O, N—H⋯O and C—H⋯O, with D⋯A ranging from 2.548 (5) to 3.393 (6) A] and ion pairing.

Guanidinium (aqua-2κO)(4-hydr-oxy-6-carboxy-pyridine-2-carboxyl-ato-2κO,N,O)(μ-4-hydroxy-pyridine-2,6-dicarboxyl-ato-1:2κO,N,O:O)(4-hydroxy-pyridine-2,6-dicarboxyl-ato-1κO,N,O)dizincate(II) dihydrate.

Abstract: The title compound, (CH6N3)[Zn2(C7H3NO5)2(C7H4NO5)(H2O)]·2H2O, has an anionic binuclear complex of ZnII balanced with a guanidinium cation. There are two uncoord­inated water mol­ecules in the structure. The asymmetric unit of the compound has two different coordination types (the coordination of Zn1 is distorted trigonal-bipyramidal, while that of Zn2 is distorted octahedral) of ZnII in the crystal structure that are bridged to each other via one hypydc2− group (hypydcH2 is 4-hydroxy­pyridine-2,6-dicarboxylic acid). A variety of inter­molecular O—H⋯O, N—H⋯O and C—H⋯O hydrogen bonds involving water mol­ecules, cations and anions, and also a weak π–π inter­action [3.798 (1) A], are responsible for extending the structure into a three-dimensional network.

Poly[propane-1,3-diammonium [cuprate(II)-bis­(μ2-pyridine-2,3-dicarboxyl­ato)] trihydrate]

Abstract: The title polymeric compound {(C3H12N2)[Cu(C7H3NO4)2]·3H2O}n or {(pnH2)[Cu(py-2,3-dc)2]·3H2O}n (pn is propane-1,3-diamine and py-2,3-dcH2 is pyridine-2,3-dicarboxylic acid), was synthesized by reaction of copper(II) chloride dihydrate with a proton-transfer compound, propane-1,3-diammonium pyridine-2,3-dicarboxyl­ate or (pnH2)(py-2,3-dc), in aqueous solution. The anion is a six-coordinate complex (site symmetry \overline{1}), with a distorted octa­hedral geometry around CuII, consisting of two bidentate pyridine-2,3-dicarboxyl­ate groups and two O atoms of bridging ligands from (py-2,3-dc)2− fragments, which are located in trans positions. The (pnH2)2+ cation is disordered over two sites by the center of inversion. Inter­molecular hydrogen bonds, π–π [centroid–centroid distances of 3.539 (3) A] and C—O⋯π stacking inter­actions [O⋯Cg = 3.240 (5) A; Cg is the center of the pyridine ring], connect the various components into a supra­molecular structure.

Understanding electronic commerce adoption decision in Iranian small and medium enterprises: Integrating current theories

Abstract: The objective of this study is to develop and test an integrated conceptual model of the electronic commerce adoption based on the two dominant theoretical paradigms - the Technology Acceptance Model (TAM) and the Theory of Planned Behavior (TPB) - to validate the research model we collected data from 226 top managers/owners of SMEs and data analysis is conducted by using a structural equation modeling with LISREL. The findings present a support to the existing theoretical links of integrated model except the effect of subjective norm on behavioral intention for adopting/using of electronic commerce.

2-(2-Quinol-yl)quinolinium nitrate.

Abstract: In the cation of the title compound, C18H13N2+·NO3−, the two bicyclic ring systems form a dihedral angle of 3.84 (4)°. The nitrate anion is disordered over two orientations in a 0.9:0.1 ratio. In the crystal structure, the cations form stacks along the a axis, with short inter­molecular contacts [C⋯C = 3.330 (3) and 3.345 (4) A], and link to the anions via N—H⋯O hydrogen bonds.

Ab initio study of atropisomers of derivatives of 1,8-di-pyridine 9H-fluorene, dibenzo[b,d]furan, 9H-carbazole and dibenzo[b,d]thiophene

Abstract: Ab initio calculation at HF/6-31G ∗ and MP2/6-31G ∗ levels of theory for geometry optimization of some syn - and anti -1,8-di-pyridine 9 H -fluorene, dibenzo[ b , d ]furan, 9 H -carbazole and Dibenzo[ b , d ]thiophene are reported. The rotational barrier energy, heat of formation and Gibbs energy are determined for the conversion of the anti-(syn) to the syn (anti) -isomers at 25 °C in the gas phase. The models are chosen as isomers of 9 H -fluorene, dibenzo[ b , d ]furan, 9 H -carbazole and dibenzo[ b , d ]thiophene as scaffold with pyridine as module. Results obtained show that (at equilibrium) for most of atropisomers the syn - is favored over the anti -isomer. Moreover, the ground state structures show that the modules are not parallel to each other but are tilted away in order to increase separation and there by minimize electrostatic repulsion. In atropisomers of 9 H -carbazole the isomers are showing an attraction due to the presence of nitrogen atom. Influence of the position of nitrogen atom on the magnitude of the rotational barriers in these atropisomers is also studied.

Synthesis of Enaminones and Their Reaction with Dimethyl Acetylene Dicarboxylate

Abstract: In present paper a simple procedure for the synthesis of enaminones without catalyst from 1,3-diketones that reacted with primary or secondary amines in ethanol as solvent, as well as the reaction of enaminones with unsaturated esters such as dimethyl acetylene dicarboxylate are reported.

Molecular characterization of a Squalene epoxidase gene in dermatophyte pathogen Trichophyton tonsurans.

Abstract: Background: Trichophyton tonsurans is one of the dermatophyte fungi which invades the skin and hair of human. Several properties of this fungus have been investigated so far. However a few studies were carried out in the field of molecular biology of this fungus. In the present study, we tried to identify the Squalene epoxidase gene which is related to synthesis of ergosterol in this fungus. Methods: Pairs of 23 and 24 nucleotides primers were designed from highly conserved regions of the similar genes in other fungi. Mentioned primers were utilized in PCR by using isolated genomic DNA of T. tonsurans whereas the PCR fragments were then sequenced. Results and Conclusion: Nucleotides (n = 558) have been sequenced from this new gene which encodes a polypeptide with 186 amino acids. Sequences comparison in gene data banks (NCBI, NIH) for this part of DNA and its deduced amino acid revealed significant homology with members of the eukaryotic Squalene epoxidase. Iran. Biomed. J. 12 (1): 55-58, 2008

Using Knowledge Management in DMAIC methodology of Six Sigma projects

Abstract: Six Sigma as a powerful approach moves toward continuous and sustainable improvement by increasing customer satisfaction, and decreasing activity time and number of failures. On the other hand, Knowledge Management (KM) is a modern approach that deals with the greatest capital of organization i.e. knowledge. Although creation of more organizational knowledge for performance improvement, organization deployment, competitiveness increase, and acquiring more benefit were the overall aims of these two approaches, and Six Sigma achievements are also based on proper knowledge and its flow, a logical relationship can be seen between them. In addition, each of them aims to support growth, profitability and power another one. In this article, after reviewing the literature of studies on this relation, the link between KM and Six Sigma is investigated, and finally usage of KM tools in parts of DMAIC methodology as a practical and effective methodology for Six Sigma, have been covered.

catena-Poly[[[aqua-cadmium(II)]bis-(μ-4-hydroxy-pyridine-2,6-dicarboxyl-ato)[aqua-cadmium(II)]di-μ-aqua] tetra-hydrate].

Abstract: The title polymeric compound, {[Cd2(C7H3NO5)2(H2O)4]·4H2O}n or {[Cd2(hypydc)2(H2O)4]·4H2O}n (where hypydcH2 is 4-hydroxy­pyridine-2,6-dicarboxylic acid), was synthesized by the reaction of cadmium(II) nitrate hexa­hydrate with 4-hydroxy­pyridine-2,6-dicarboxylic acid and propane-1,3-diamine, in a 1:2:2 molar ratio in aqueous solution. The compound is a seven-coordinate binuclear polymeric complex with distorted penta­gonal bipyramidal geometry around CdII [Cd—O = 2.247 (4)–2.474 (3) A]. In the binuclear monomeric units, the central atoms join together by O atoms of two bridging tridentate (hypydc)2− ligands, and the polymer propagates via two bridging water mol­ecules that link each CdII centre of one monomer to the adjacent neighbour. Propane-1,3-diamine (pn) does not appear in the product but plays a role as a base. Inter­molecular O—H⋯O and C—H⋯O hydrogen bonds, and π–π stacking inter­actions, with distances of 3.725 (3) and 3.766 (3) A, connect the various components.

Propane-1,2-diammonium bis­(pyridine-2,6-dicarboxyl­ato-κ3O,N,O′)nickelate(II) tetra­hydrate

Abstract: The reaction of nickel(II) nitrate hexa­hydrate, propane-1,2-diamine and pyridine-2,6-dicarboxylic acid in a 1:2:2 molar ratio in aqueous solution resulted in the formation of the title compound, (C3H12N2)[Ni(C7H3NO4)2]·4H2O or (p-1,2-daH2)[Ni(pydc)2]·4H2O (where p-1,2-da is propane-1,2-diamine and pydcH2 is pyridine-2,6-dicarboxylic acid). The geometry of the resulting NiN2O4 coordination can be described as distorted octa­hedral. Considerable C=O⋯π stacking inter­actions are observed between the carboxyl­ate C=O groups and the pyridine rings of the (pydc)2− fragments, with O⋯π distances of 3.1563 (12) and 3.2523 (12) A and C=O⋯π angles of 95.14 (8) and 94.64 (8)°. In the crystal structure, a wide range of non-covalent inter­actions, consisting of hydrogen bonding [O—H⋯O, N—H⋯O and C—H⋯O, with D⋯A distances ranging from 2.712 (2) to 3.484 (2) A], ion pairing, π–π [centroid-to-centroid distance = 3.4825 (8) A] and C=O⋯π stacking, connect the various components to form a supra­molecular structure.

Poly[tetra­aqua-μ3-pyridine-3,5-dicarboxyl­ato-strontium(II)]

Abstract: The reaction of strontium(II) nitrate with the proton-transfer compound (pdaH2)(py-3,5-dc)·H2O (where pda = propane-1,3-diamine and py-3,5-dcH2 = pyridine-3,5-dicarboxylic acid) leads to the formation of the title polymeric compound, [Sr(C7H3NO4)(H2O)4]n. The propane-1,3-diaminium cation is not incorporated in this crystal structure. The SrII atom lies on an inversion centre and is eight-coordinated by four O atoms from three py-3,5-dc ligands and four O atoms from four coordinated water mol­ecules. The coordination polyhedron of the SrII atom is a distorted dodeca­hedron. These binuclear units are connected via the carboxyl­ate O atoms to build a one-dimensional polymeric chain. In the crystal structure, non-covalant inter­actions consisting of hydrogen bonds (X—H⋯O, with X = O and C) and π–π stacking inter­actions [3.4604 (19) A] connect the various components to form a supra­molecular structure.

Bis(2,4,6-trimethyl-pyridinium) hexa-chloridoplatinate(IV).

Abstract: The asymmetric unit of the title compound, (C8H12N)2[PtCl6], contains one independent protonated 2,4,6-trimethyl­pyridinium cation and one half of a centrosymmetric [PtCl6]2− anion. The Pt ion has an almost ideal octa­hedral coordination. In the crystal structure, intra­molecular N—H⋯Cl and inter­molecular C—H⋯Cl hydrogen bonds result in the formation of a supra­molecular structure.

Effect of Metasystox-R on marine Nitrosomonas sp. as a nitrification inhibitor.

Abstract: Metasystox-R is a systemic soluble liquid insecticide for the control of aphids on brassica vegetable crops, cotton and lupins and it is possible enter to the marine environment and may be have a hazard effects for the marine organisms and nitrification processes. Effect of Metasystox-R on ammonia oxidizing activity by marine Nitrosomonas sp. was investigated by determining nitrification inhibitor assay in the cell suspension. Results showed that 8 microg mL(-1) of Metasystox-R with PI50 = 4.48 significantly inhibited nitrite production by marine Nitrosomonas sp. These results suggested marine Nitrosomonas sp. may be one of the target bacteria which was inhibitor and decreasing nitrification in the marine environment.

Synthesis of New Rigid Dimeric Calix[4]arene

Abstract: A new Dimeric calixarene from the head to head linkage of two calix[4]arene units fixed in the cone conformation was synthesized via Sonogashira cross-coupling reaction. The structure of 10 was confirmed by NMR, MS and IR-spectroscopy.

catena-Poly[[triaqua­cadmium(II)]-μ-pyridine-2,3-dicarboxyl­ato-κ3N,O2:O3]

Abstract: The title polymeric compound, [Cd(C7H3NO4)(H2O)3]n or [Cd(py-2,3-dc)(H2O)3]n, where py-2,3-dcH2 is pyridine-2,3-dicarboxylic acid, was obtained by the reaction of cadmium(II) nitrate hexa­hydrate with (pipzH2)(py-2,3-dc) as a proton-transfer compound in aqueous solution (pipz is piperazine). The mol­ecular structure shows that only the anionic fragment of the starting proton-transfer compound is present in the complex, while the (pipzH2)2+ dication has been lost. Each (py-2,3-dc)2− ligand bridges two CdII atoms in two different coordination modes, i.e. one end acts as a monodentate and the other end as a bidentate ligand. The three remaining coordination sites on the metal center are occupied by water mol­ecules. The geometric arrangement of the six donor atoms around the CdII atom is distorted octa­hedral. In the crystal structure, O—H⋯O and C—H⋯O hydrogen bonds play an important role in stabilizing the supra­molecular structure.