Characterization of antithrombin III from human plasma by two-dimensional gel electrophoresis and capillary electrophoretic methods

The isoforms distribution of the glycoprotein antithrombin III (ATIII) derived from human plasma was investigated by means of isoelectric focusing (IEF) in polyacrylamide gels with immobilized pH gradients (IPG) and two-dimensional gel electrophoresis (2-DE) as well as capillary electrophoretic methods. It turned out that the presence of high concentrations of chaotropics (urea, thiourea) and zwitterionic detergents (3-[(3-cholamidepropyl)dimethylammonio]-1-propanesulfonate (CHAPS)) was decisive for attaining good resolution of the protein isoforms. Resolution by IPG-IEF was obtained with excellent reproducibility and pI differences down to 0.01 pH units could be distinguished. ATIII-alpha and ATIII-beta-fractions preseparated by heparin affinity chromatography showed an analogous but shifted spot pattern consisting each of one major and three minor isoforms. The main isoforms of ATIII-alpha and ATIII-beta exhibit pI values of 5.18 and 5.32, respectively, both values determined in the presence of high concentrations of urea. The pI difference of 0.14 pH units correspond to the effect of two sialic acids absent in ATIII-beta. The formation and occurrence of ATIII dimers and trimers turned out to be dependent on the sample preparation. The results obtained by 2-DE were compared with those of capillary zone electrophoresis (CZE) and capillary IEF (CIEF). Quantitative analysis regarding the CZE separated isoforms of plasma derived ATIII yielded a content of about 70% ATIII-alpha main isoform and about 6.6% of ATIII-beta. The pI values of ATIII determined by CIEF with internal calibration were in fair agreement with the pI values of the main isoforms achieved with 2-DE.     

Comparison of the Dynamics of Water Molecules in Crystals of Proton-Ordered Ice IX and Its Proton-Disordered Analog III

A computer simulation of proton-ordered ice IX and its proton-disordered analog III (768 molecules, 90 K) was carried out by the molecular dynamics method using Poltev–Malenkov's potential. For ice IX, the differences in the dynamic characteristics of molecules with O(1) and O(2) are much wider than those in the case of ice III. The libration spectrum of ice IX has a number of distinct acute peaks, and the spectrum of ice III is strongly smoothed. These peculiarities are explained by the proton ordering of ice IX and disordering of ice III. The latter is responsible for the great differences in the short- and especially long-range environment of water molecules in ice crystals and hence for the presence of many molecules with different dynamic characteristics. Thus averaging over a large number of different vibrational spectra of molecules leads to a smoothed total spectrum in the case of the proton-disordered crystal modification of ice.     

Density and Sound Velocity Studies of Aqueous Solutions of Tetradecyltrimethylammonium Nitrate at Different Temperatures

The density and ultrasound velocity of aqueous solutions of tetradecyltrimethylammonium nitrate were measured in the temperature range of 15 to 35°C in 5°C intervals. The concentration range covered the premicellar and micellar regimes. By assuming a pseudophase separation model for the micellar system, we applied the densitometric data to estimate the apparent molar volumes and the apparent thermal expansibility coefficients of the surfactant in monomeric and micellar forms. Ultrasound velocity and density data enabled us to estimate the isentropic compressibility of the surfactant in both forms. The results are compared with relevant literature data for alkyltrimethylammonium bromides.     

Thermal transformations in systems based on zeolites Y,X, and A containing zinc and sodium nitrates

Thermal transformations in systems formed by interaction of Zn and Na nitrates with Y, X, and A zeolites were studied by TG—DTA technique. Temperature regions of existence of adsorbed water, water of crystallization, and decomposition of NO₃ ^– anion were determined. These intervals depend on the composition, structure, method of preparation, and pre-treatment conditions of zeolite systems. The extent of NO₃ ^– decomposition depends not only on the zinc and sodium content but also on the presence of ammonia involved in NO₃ ^– reduction. The zeolite matrix strongly stabilizes the occluded NO₃ ^– anions. A portion of zinc oxide formed by zinc nitrate decomposition is probably localized inside the zeolite cavities as the [Zn—O—(ZnO) _n —Zn]²⁺ particles. The latter compensate charges of the isolated [AlO₄]^– tetrahedra.     

Reaction Mechanisms of Strontium Ferrites Synthesis

The reactions between strontium and iron nitrates have been studied in an open atmosphere system using three different molar ratios, 1:1 (I), 1:2 (II) and 2:1 (III) at different temperatures as pointed out from the DTA data. The reaction mechanism was discussed based on the chemical composition characterized by means of thermal analysis, X‐ray diffraction patterns, infrared spectra and magnetic susceptibility. It was found that the reaction products depend on both temperature of reaction and the ratio between reactants. The reaction products were found to be composed of a variety of iron compounds that possess different valences: SrFeO_2.86, SrFeO_2.97, SrFe₂O₄, SrFe₁₂O₁₉, Sr₂Fe₂O₅ and Sr₇Fe₁₀O₂₂ in addition to some accessory reaction products namely α‐Fe₂O₃ and FeO(OH).     

Simultaneous Determination of Chromium Species in Water and Plant Samples at Trace Levels by Ion Chromatography–Inductively Coupled Plasma-Mass Spectrometry

Ion chromatography–inductively coupled plasma-mass spectrometry (IC–ICP-MS) was used for the identification and quantification of chromium species. Chromium(III) and chromium(VI) were separated and determined by IC–ICP-MS. The separation was achieved using an anion exchange column with 0.55?M HNO₃ as mobile phase. It was a particular goal of this work to exclusively use nitric acid for elution in order to reduce interferences in the ICP-MS system. Analytical figures of merit were calculated under the optimum conditions by developing calibration plots in a concentration range of 0.50–250?µg/L for both species. The detection limits for Cr(III) and Cr(VI) were 0.09 and 0.03?µg/L, respectively. Spiked recovery tests were used to evaluate the applicability of the analytical method in environmental samples, and the recoveries ranged between 97 and 103% for both analytes. The accuracy of the method for total chromium content was validated through the analysis of a spring water-certified reference material (UME 1201), and the obtained results were in good agreement with the certified value. Lettuce seedlings were cultivated to evaluate the intake levels of these species. In addition, the bioaccessibility of Cr(III) and Cr(VI) from the lettuce seedlings in simulated gastric and intestinal fluids media was examined.     

Facile synthesis of 1-(arylimino)naphthalen-2(1H)-ones from anilines and 2-naphthols promoted by NaBr/K2S2O8/CAN

An efficient method has been developed for the synthesis of 1-(arylimino)naphthalen-2(1H)-ones through the cascade reaction of anilines and 2-naphthols promoted by NaBr/K₂S₂O₈/Ce(NH₄)₂(NO₃)₆. Using this protocol, a series of 1-(arylimino)naphthalen-2(1H)-ones was obtained in good to excellent yields (17 examples, 70–92% yields). The reactions may proceed through the following steps: bromination of 2-naphthols by in-situ-generated bromine from NaBr and K₂S₂O₈ to afford 1-bromonaphthalen-2-ols, coupling of 1-bromonaphthalen-2-ols with anilines to afford the corresponding amines, and subsequent oxidation of the amines into the products by Ce(NH₄)₂(NO₃)_6. These newly obtained α-imine ketones have great potentials for synthesis of special optical materials bearing naphthalene moiety.     

Potentiometric and antimicrobial studies on the asymmetric Schiff bases and their binuclear Ni(II) and Fe(III) complexes; synthesis and characterization of the complexes

The protonation constants of two nitro-Schiff bases SB¹, SB² and three asymmetric tetradentate diimines H₂L¹, H₂L² and H₂L³ and the stability constants of their ML type binuclear Ni(II) and Fe(III) complexes have been determined potentiometrically. The asymmetric diimines are (2OH) RCHNC₆H₄CHNR′ (2OH) type compounds [where R = R′ = phenyl for H₂L¹; R = naphthyl, R′ = phenyl for H₂L² and R = R′ = naphthyl for H₂L³]. The effect of tautomeric forms on the acid-base properties of the diimines has been investigated and discussed. In addition, dimeric and binuclear Ni(II) and Fe(III) complexes of the diimines have been synthesized and characterized by physical and spectroscopic techniques. Also, in vitro antimicrobial activities of the diimines and the complexes have been evaluated against three bacteria: Micrococcus luteus (NRLL B-4375), Bacillus cereus (RSKK 863), Escherichia coli (ATCC 11230) and the fungus: Candida albicans (ATCC 10239).     

Solvent effects on catalytic activity of manganese porphyrins with cationic,anionic and uncharged meso substituents: Indirect evidence on the nature of active oxidant species

Oxidation of cyclohexene and styrene with sodium periodate and tetra‐n‐butylammonium periodate (TBAP) catalyzed by MnT(3‐MePy)P(OAc), MnT(4‐SO₃)PP(OAc) and MnTPP(OAc) has been studied in water, methanol, acetonitrile and dichloromethane as solvents. The results show significant dependence of the product distribution on the type of solvent and the electronic nature of the aryl substituents introduced at the porphyrin periphery. While the oxidation of cyclohexene and styrene in the presence of MnT(3‐MePy)P(OAc) and MnTPP(OAc) in water (also in methanol) gave the corresponding epoxides as nearly the sole product, performing the reactions in the presence of MnT(4‐SO₃)PP(OAc) yielded the products of allylic oxidation, cyclohexene‐2‐ol and cyclohexene‐2‐one and acetophenone as the major products. In the case of styrene, performing the reaction in the presence of MnT(4‐SO₃)PP(OAc), MnT(3‐MePy)P(OAc) and MnTPP(OAc) in acetonitrile gave a mixture of styrene oxide and acetophenone as the products. Under the same conditions, the oxidation of cyclohexene afforded cyclohexene oxide as approximately the exclusive product. Furthermore, the oxidation of olefins in dichloromethane gave the corresponding epoxide as the exclusive products. The product distributions observed in the protic and aprotic solvents were used to provide indirect evidence on the relative contribution and reactivity of high valent manganese oxo and periodato Mn(III) porphyrin species to the oxidation reactions.     

Triazine based Mn (II) and Mn (II)/Ln (III) complexes: Synthesis,characterization and catecholase activities

In the current work, two triazine‐based multidentate ligands (H₂L¹ and H₂L²) and their homo‐dinuclear Mn (II), mononuclear Ln (III) and hetero‐dinuclear Mn (II)/Ln (III) (Where Ln: Eu or La) complexes were synthesized and characterized by spectroscopic and analytical methods. Single crystals of a homo‐dinuclear Mn (II) complex {[Mn (HL¹)(CH₃OH)](ClO₄·CH₃OH}₂ ( 1 ) were obtained and the molecular structure was determined by X‐ray diffraction method. In the structure of the complex, each Mn (II) ion is seven‐coordinate and one of the phenolic oxygen bridges two Mn (II) centre forming a dimeric structure. The UV–Vis. and photoluminescence properties of synthesized ligands and their metal complexes were investigated in DMF solution and the compounds showed emission bands in the UV–Vis. region. The catecholase enzyme‐like activity of the complexes were studied for 3,5‐DTBC → 3,5‐DTBQ conversion in the presence of air oxygen. Homo‐dinuclear Mn (II) complexes ( 1 and 4 ) were found to efficiently catalyse 3,5‐DTBC → 3,5‐DTBQ conversion with the turnover numbers of 37.25 and 35.78 h^?1 (k_cat), respectively. Mononuclear Eu (III) and La (III) complexes did not show catecholase activity.