Showing papers by "Bu-Ali Sina University published in 2004"
01 Aug 2004
TL;DR: The theoretical results (derived equations) show that the observed rate constants of pseudo-first-order and pseudo-second-order models are combinations of adsorption and desorption rate constants and also initial concentration of solute.
Abstract: The kinetics of sorption from a solution onto an adsorbent has been explored theoretically. The general analytical solution was obtained for two cases. It has been shown that at high initial concentration of solute (sorbate) the general equation converts to a pseudo-first-order model and at lower initial concentration of solute it converts to a pseudo-second-order model. In other words, the sorption process obeys pseudo-first-order kinetics at high initial concentration of solute, while it obeys pseudo-second-order kinetics model at lower initial concentration of solute. The theoretical results (derived equations) show that the observed rate constants of pseudo-first-order and pseudo-second-order models are combinations of adsorption and desorption rate constants and also initial concentration of solute. The obtained theoretical equations are used to correlate experimental data for sorption kinetics of some solutes on various sorbents. The predictions of the theory are in excellent agreement with the experimental data.
1,860 citations
TL;DR: In this article, the mean centering (MC) of ratio kinetic profiles is used for the simultaneous determination of binary mixtures without prior separation steps, and the results from experimental data relating to the simultaneous spectrophotometric determination of Co(II and Ni(II) based on their complexation reactions with 1-(2′-pyridylazo)-2-naphthol (PAN) in micellar media were presented as a real model for resolution of the binary systems.
97 citations
TL;DR: The results indicate that mature pollen have more allergenicity than immature pollen, and polluted pollen grains are more effective than nonpolluted pollen grains in inducing allergic symptoms.
81 citations
TL;DR: The polluted pollen is more effective than non-polluted one, and mature pollen has more allergy potency than immature one, according to these experiments and regarding induction of allergic symptoms.
Abstract: The prevalence of allergic disease has increased world wide during the last decades. Pollen allergy is the most typical form of allergic disease. The increase in its frequency during recent years is the most evident. Environmental factors play an important role in the problem of pollen allergy in large cities. The aim of this research is determination of allergenicity of Canna pollen in polluted and non-polluted conditions, detection of their allergenic proteins and also elucidation of some microscopic effects of air pollutants on pollen structure and proteins. Mature and immature pollen grains of Canna indica were collected from polluted and non-polluted areas. Pollen grains were studied by scanning electron microscopy. Mice were sensitized by injection of pollen extract and an adjuvant for five times. Allergy potency of different pollen extracts were compared by means of skin test, blood eosinophills number and IgE levels in sensitized and treated animals. Pollen proteins were studied by SDS-PGE and allergenic proteins were detected by immunoblotting techniques. Scanning electron microscope study of the pollen grains showed that in polluted areas, air born particles accumulated on the surface of pollen and changed both pollen's shape and pollen's tectum. Also many vesicles were released out of polluted pollen and the pollen material agglomerated on the surface of pollen. SDS-PAGE showed that different proteins exist in mature and immature pollen. In pollen collected from polluted area, some of protein bands between 22 and 45 kDa were disappeared . Also in all polluted pollen grains, protein content of pollen decreased in response to air pollution causing the release of pollen proteins. According to our experiments and regarding induction of allergic symptoms, the polluted pollen is more effective than non-polluted one, and mature pollen has more allergy potency than immature one.
78 citations
TL;DR: In this paper, the authors show that the types of polymorphs in veins correlate with Al2SiO5 polymorph(s) in the host rocks, although vein polymorphs are texturally and compositionally distinct from those in adjacent host rocks.
Abstract: Quartz-rich veins in metapelitic schists of the Sanandaj-Sirjan belt, Hamadan region, Iran, commonly contain two Al2SiO5 polymorphs, and, more rarely, three coexisting Al2SiO5 polymorphs. In most andalusite and sillimanite schists, the types of polymorphs in veins correlate with Al2SiO5 polymorph(s) in the host rocks, although vein polymorphs are texturally and compositionally distinct from those in adjacent host rocks; e.g. vein andalusite is enriched in Fe2O3 relative to host rock andalusite. Low-grade rocks contain andalusite + quartz veins, medium-grade rocks contain andalusite + sillimanite + quartz ± plagioclase veins, and high-grade rocks contain sillimanite + quartz + plagioclase veins/leucosomes. Although most andalusite and sillimanite-bearing veins occur in host rocks that also contain Al2SiO5, kyanite-quartz veins crosscut rocks that lack Al2SiO5 (e.g. staurolite schist, granite). A quartz vein containing andalusite + kyanite + sillimanite + staurolite + muscovite occurs in andalusite–sillimanite host rocks. Textural relationships in this vein indicate the crystallization sequence andalusite to kyanite to sillimanite. This crystallization sequence conflicts with the observation that kyanite-quartz veins post-date andalusite–sillimanite veins and at least one intrusive phase of a granite that produced a low-pressure–high-temperature contact aureole; these relationships imply a sequence of andalusite to sillimanite to kyanite. Varying crystallization sequences for rocks in a largely coherent metamorphic belt can be explained by P–T paths of different rocks passing near (slightly above, slightly below) the Al2SiO5 triple point, and by overprinting of multiple metamorphic events in a terrane that evolved from a continental arc to a collisional orogen.
66 citations
TL;DR: In this paper, a gravity-drop model hammer was employed to carry out several ring tests at medium strain rates with lead as the model material, and the results showed that a full range of friction conditions, from zero friction to sticking friction, could be modelled for the physical simulation of the bulk metal forming processes.
62 citations
TL;DR: In this paper, an ion-selective electrode (ISE) sensitive to sodium dodecyl sulfate (SDS) has been used to study the micellar and premicellar behavior of SDS in ethanol/water and 1-propanol/water mixtures at 303 K.
56 citations
TL;DR: In this paper, a reagent for crossed-aldol condensation with ketones in the presence of silica sulfuric acid under solvent-free conditions is described. But the reagent is reusable for several times without any decrease in the yield of the reactions.
Abstract: Aromatic aldehydes undergo crossed-aldol condensation with ketones in the presence of silica sulfuric acid under solvent-free conditions to afford the corresponding a, b-unsaturated aldol products in excellent yields. The reagent is reusable for several times without any decrease in the yield of the reactions.
55 citations
TL;DR: Under working conditions, the proposed HPSAM method was successfully applied to the simultaneous determination of hydrazine and phenylhydrazine in several synthetic mixtures and plasma and water samples.
55 citations
TL;DR: Morphological and physiological characters, the internal transcribed spacer regions of the rDNA cluster (ITS1-5.8SrDNA-ITS2) and partial sequences of translation elongation factor 1-alpha (tef1) are described.
Abstract: Trichoderma brevicompactum, a new spe- cies, was isolated from soil or tree bark in North, Cen- tral and South America, including the Caribbean Is- lands, and southwestern and southeastern Asia. Mor- phological and physiological characters, the internal transcribed spacer regions of the rDNA cluster (ITS1- 5.8SrDNA-ITS2) and partial sequences of translation elongation factor 1-alpha (tef1) are described. Tricho- derma brevicompactum is characterized by a pachyba- sium-type morphology, morphologically resembling other small-spored species referable to Trichoderma section Pachybasium but with essentially subglobose conidia. It is most closely related phylogenetically to Hypocrea lutea, from which it differs in morphologi- cal and physiological characters.
49 citations
TL;DR: The Pabdeh Formation is part of a thick carbonate-siliciclastic succession in the Zagros Basin of SW Iran which includes carbonate reservoirs of Cretaceous and Cenozoic ages.
Abstract: The Pabdeh Formation is part of a thick carbonate-siliciclastic succession in the Zagros Basin of SW Iran which includes carbonate reservoirs of Cretaceous and Cenozoic ages. From field observations and petrographic and facies analysis of exposures in the type section of the Pabdeh Formation, four lithofacies were recognized. These are from oldest to youngest: (i) a mottled, bioturbated bioclastic wackestone/mudstone facies; (ii) a wackestone/packstone facies with horizontal burrows on bedding planes; (iii) a thin-bedded bioclastic wackestone/mudstone facies alternating with thin bioclastic-oolitic-intraclastic intervals; and (iv) a bioclastic foraminiferal / algal / peloidal packstone facies. These observations indicate that facies evolved upwards from deep outer-ramp deposits to inner-ramp deposits within a shoal complex, suggesting progradation of the ramp depositional system. Storm events significantly influenced the ramp system. Storm-generated surges transported sediments from nearshore to the deeper outer-ramp environment where they were deposited as shell-lags, composed mostly of bioclastic packstones, rich in pelagic microfauna with sharp, undulatory erosional basal contacts. The packstones rest on outer ramp mudstones deposited below storm base level. Sedimentary structures in the Pabdeh Formation are those typical of storm deposits, such as hummocky cross-stratification, ripple cross-lamination, ripple marks, escape burrows on the tops of the beds, couplets of fine- and coarse-grained laminae and mixed fauna, as well as intraclasts derived from underlying facies. These distinctive sequences are interpreted to have been generated by waning storm-generated currents. The dominance of fine-grained sediments (medium to fine sand); the lack of large- scale hummocky cross-stratification; the minor amounts of intraclasts derived from underlying facies; the paucity of amalgamated tempestite beds; and the finely-laminated (mm to cm scale) couplets of coarse and fine lamina all suggest a distal tempestite facies. Palaeogeographic reconstruction of the Zagros Basin during the Eocene indicates that the study area was situated in tropical, storm-dominated palaeolatitudes.
TL;DR: Trichloroisocyanuric acid is used as an effective oxidizing agent for the oxidation of 1,3,5-trisubstituted pyrazolines to their corresponding pyrazoles under both heterogeneous and also solvent free conditions with good yields at room temperature as mentioned in this paper.
TL;DR: The present data suggest that ultra-low doses of opioid receptor antagonists may provide a potent strategy to modulate seizure susceptibility, especially in conjunction with very low doses of opioids.
TL;DR: H 3 PMo 12 O 40 · xH 2 O was found to be an effective catalyst for the preparation of bis-indolyl derivatives from indole and aromatic, aliphatic, heterocyclic aldehydes or ketones in ethanol at room temperature.
Abstract: H 3 PMo 12 O 40 · xH 2 O was found to be an effective catalyst for the preparation of bis-indolyl derivatives from indole and aromatic, aliphatic, heterocyclic aldehydes or ketones in ethanol at room temperature.
TL;DR: In this article, the crystal structure of a Mg(II) bis(pendant arm) macrocyclic Schiff-base complexes, [MgLn]2+(n=5, 6, 7), have been prepared via cyclocondensation of 2,6diacetylpyridine with branched hexaamines and characterised spectroscopically.
TL;DR: Silica phosphoric acid was prepared via reaction of silica chloride (I) and phosphoric acids as mentioned in this paper, which can be readily converted to their corresponding thionitrites with a combination of Silica Pimentoric Acid (II), wet SiO 2, and sodium nitrite in dichloromethane at room temperature.
Abstract: Silica phosphoric acid was prepared via reaction of silica chloride (I) and phosphoric acid. Thiols can be readily converted to their corresponding thionitrites with a combination of silica phosphoric acid (II), wet SiO 2 , and sodium nitrite in dichloromethane at room temperature. Disulfides result from the homolytic cleavage of the sulfur–nitrogen bond of the unstable thionitrite and subsequent coupling of the resultant thiyl radicals.
TL;DR: In this article, various types of 2-imidazolines are efficiently oxidized to the corresponding imidazoles using potassium permanganate supported on silica gel under mild conditions at room temperature.
TL;DR: The unsymmetrical PCP′ pincer ligands {C6H4-1-CH2PPh2-3-CH 2PBut2} and the corresponding palladium complexes were synthesized in good yields as discussed by the authors.
TL;DR: In this article, the authors used finite element analysis to predict the optimum shrinkage radius of a compound cylinder with a constant ratio of outer to inner radii, k = 2.2.
TL;DR: The steady states of three families of one-dimensional non-equilibrium models with open boundaries, first proposed in N. J. Phys. 5 (2003) 145.1, are studied using a matrix product formalism.
Abstract: The steady states of three families of one-dimensional non-equilibrium models with open boundaries, first proposed in N. J. Phys. 5 (2003) 145.1, are studied using a matrix product formalism. It is shown that their associated quadratic algebras have two-dimensional representations, provided that the transition rates lie on specific manifolds of parameters. Exact expressions for the correlation functions of each model have also been obtained. We have also studied the steady-state properties of one of these models, first introduced in J. Phys. A: Math. Gen. A 36 (2003) 74, with more details. By introducing a canonical ensemble we calculate the canonical partition function of this model exactly. Using the Yang–Lee theory of phase transitions we spot a second-order phase transition from a power law to a jammed phase. The density profile of particles in each phase has also been studied. A simple generalization of this model in which both the left and the right boundaries are open has also been introduced. It is shown that double shock structures may evolve in the system under certain conditions.
TL;DR: In this paper, the binding of a homologous series of n-alkyltrimethylammonium bromides to bovine serum albumin was measured in 2.7 mM phosphate buffer, pH 7.0, and at various temperatures using surfactant membrane selective electrodes as a fast and accurate method.
Abstract: The binding of a homologous series of n-alkyltrimethylammonium bromides to bovine serum albumin were measured in 2.7 mM phosphate buffer, pH 7.0, and at various temperatures using surfactant membrane selective electrodes as a fast and accurate method. The obtained binding isotherms have been analyzed and interpreted using the binding capacity concept, Hill equation and Wyman binding potential. The system behaved as a system with two sets of binding sites in all studied situations. The results represent the essential role of hydrophobic interactions in the first binding set. At high cationic surfactant concentrations, the occupation of the second binding set occurred, with an accompanying unfolding and exposure of numerous hydrophobic binding sites. However, this unfolding process occurred for the cationic surfactant at much higher concentrations than was required for sodium dodecyl sulfate. The Gibbs free energy change calculated on the basis of the Wyman binding potential concept decreases in the initial stages of binding and passes through a minimum, followed by occupation of the second binding set. The affinity of binding increased with increasing temperature, indicating an endothermic and essentially entropy driven process.
TL;DR: Alcohols are acetylated in a mild, clean, and efficient reaction with acetic anhydride in the presence of a catalytic amount of Al(HSO4)3 in solution and under solvent free conditions.
Abstract: Alcohols are acetylated in a mild, clean, and efficient reaction with acetic anhydride in the presence of a catalytic amount of Al(HSO4)3 in solution and under solvent free conditions. All reactions were performed at room temperature in good to high yields.
TL;DR: The behavior of the inclusion complex consisting of tetradecyltrimethylammonium bromide (TTAB) and β-cyclodextrin (β-CD) was studied using ion selective electrodes sensitive to surfactant ions as discussed by the authors.
Abstract: The behavior of the inclusion complex consisting of tetradecyltrimethylammonium bromide (TTAB) and β-cyclodextrin (β-CD) was studied using ion selective electrodes sensitive to surfactant ions. Two...
TL;DR: In this article, Maleki and Maleki described five-membered heterocyclic compounds are used commercially as pharma-ceuticals, pesticides, and dyestuffs and showed that these compounds are also important constituents that often exist in biologicallyactive natural products and synthetic compounds ofmedicinal interest.
Abstract: and Behrooz MalekiChemistry Department, College of Science, Bu-Ali Sina University, Hamadan 65174, IranReceived July 9, 2003Key Words : 1,3-Dibromo-5,5-dimethylhydantoin (DBH), 1,3,5-Trisubstituted pyrazolines, Pyrazoles,Solvent-free conditionsFive-membered heterocyclic compounds are stable aromaticcompounds and have been used commercially as pharma-ceuticals, pesticides, and dyestuffs. These compounds arealso important constituents that often exist in biologicallyactive natural products and synthetic compounds ofmedicinal interest.
TL;DR: The main constituents of the essential oil were thymol(42.8% and 43.1%), linalool (11.1% and 4.0%), γ-terpinene (6.0% and 6.3%), 1,8-cineole (5.6% and 3.3%) and α-terpineol (1.9%) as mentioned in this paper.
Abstract: Essential oils isolated by hydrodistillation from the aerial parts of Thymus eriocalyx (Ronniger) Jalas,before flowering and full flowering stage, were analysed by a combination of capillary GC and GC–MS. Seventy com-ponents were identified, constituting approximately 92.5% of the oil. The main constituents of the essential oil were thymol(42.8% and 43.1%), linalool (11.1% and 4.0%), γ -terpinene (6.0% and 6.3%), 1,8-cineole (5.6% and 3.3%), borneol (3.4%and 4.9%) and α -terpineol (1.8% and 7.1%) at before flowering (10 days before bloom formation) and full flowering stage,respectively. Copyright © 2004 John Wiley & Sons, Ltd. KEY WORDS: Thymus eriocalyx ; Labiatae; essential oil composition; thymol; linalool; γ-terpinene; 1,8-cineole; borneol; α-terpineol; Iran * Correspondence to: F. Sefidkon, Research Institute of Forests andRangelands, PO Box 13185-116, Tehran, Iran Experimental Plant Material The aerial parts of Thymus eriocalyx were collectedfrom the Absar Mountain, Late Dar Village, altitude2300–2500 m (Markazi Province, 40 km to Arak) atbefore flowering and full flowering stage on May andJune 2002, respectively. A voucher specimen has beendeposited in the Herbarium of the Research Institute ofForests and Rangelands (TARI).
TL;DR: Interference effects of common anions and cations were studied and the method was applied to simultaneous determination of Co( II) and Ni(II) in alloy samples and was compared with derivative spectrophotometric method.
TL;DR: 2-Imidazolines were selectively converted to their corresponding imidazoles in the presence of other oxidizable functional groups such as sulfide, ether, aldehyde, acetal and THP ether.
TL;DR: In this paper, the nucleophilic ring opening reactions of epoxides by aliphatic alcohols and water are achieved efficiently in the presence of catalytic amounts of silica sulfuric acid with high degree of regioselectivity.
Abstract: The nucleophilic ring opening reactions of epoxides by aliphatic alcohols and water are achieved efficiently in the presence of catalytic amounts of silica sulfuric acid with high degree of regioselectivity. The catalyst is reusable and can be applied several times without any decrease in the yield of reactions.
TL;DR: In this article, a mild and efficient method for the oxidative coupling of thiols by ammonium dichromate in the presence of silica chloride and wet SiO2 in solution and under solvent free conditions is reported.
TL;DR: In this article, the authors used Silica sul fu ric acid and so dium dichromate dihydrate or po tas sium per manga nate in the presence of wet SiO2 was used as an ef fec tive ox i diz ing agent for ox i da tion of al co hols to their cor re spond ing al de hydes or ke tones in sol vent free con di tions.
Abstract: A com bi na tion of sil ica sul fu ric acid and so dium dichromate dihydrate or po tas sium per manga nate in the pres ence of wet SiO2 was used as an ef fec tive ox i diz ing agent for ox i da tion of al co hols to their cor re spond ing al de hydes or ke tones in sol vent free con di tions.