bluuebunny/crossref_metadata_2025 huggingface dataset:
Diagnostic value of CSF proteins assay in differential diagnosis of CNS disease
Authors: Vukosavljevic Dragana , Bumbasirevic Ljiljana , Stefanovic Aleksandra , Stojanov Marina
Published: August 2005

The differential diagnosis between inflammatory and noninflammatory diseases of CNS includes CSF quantitative measurements of immunoglobulin and albumin concentrations and their comparison to the serum. For that purpose we estimated the concentrations of albumin and immunoglobulin G both in CSF and serum of patients with inflammatory and noninflammatory diseases of CNS. Parallely, these parameters were determined in the control group composed of patients having the values of investigated parameters within reference ranges. The obtained data were statistically evaluated by nonparametric Mann-Whitney test. The values of calculated CSF/albumin ratio have shown significant differences between the both patient groups and the control one (p < 0.001). It proves that in each examined group the blood brain barrier is damaged. For the assessment of intrathecal IgG synthesis we have calculated both IgG/albumin index and Schuller index. The comparison of the values obtained for patients with noninflammatory diseases to the control one, revealed no statistically significant differences (p > 0.05). On the contrary, significant difference have been observed between the group with inflammatory diseases and the control (p < 0.05), proving the existence of IgG intrathecal synthesis. Values of both indexes were much higher in patients with inflammatory than noninflamatory diseases, meaning that they can be used in differential diagnosis.
A possible protective role of coenzyme Q10 on antioxidant defense system in the heart of rats treated with cadmium
Authors: Pavlovic Sladjan , Ognjanovic Branka , Stajn Andras , Zikic Radoslav , Radojicic Ratko , Spasic Mihajlo , Saicic Zorica
Published: August 2005

The effect of cadmium (Cd), coenzyme Q10 (CoQ10) and Cd+CoQ10 on the activities of superoxide dismutases (total SOD), manganese containing superoxide dismutase (Mn SOD) and copper-zinc containing superoxide dismutase (Cu,Zn SOD), catalase (CAT), glutathione peroxidase (GSH-Px), glutathione-Stransferase (GST), glutathione reductase (GR) and concentrations of ascorbic acid (AsA) and vitamin E (Vit E) in the heart of male Wistar albino rats were studied in comparison to the controls and cadmium treated animals. Cd induces a significant increase of total SOD, Cu, Zn SOD and GSH-Px activities, as well as AsA and Vit E concentrations, but leads to a significant decrease of CAT and GR activities. CoQ10 induces a significant increase of total SOD, Mn SOD, Cu, Zn SOD and GSH-Px activities, as well as AsA and Vit E concentrations. In the same group of animals the activities of CAT, GST and GR were significantly decreased. By concomitant treatment of rats with Cd+CoQ10 the activities of total SOD, Mn SOD and GSH-Px, as well as concentrations of AsA and Vit E were markedly increased. In the same group of animals the activities of Cu, Zn SOD, CAT and GR were significantly decreased. In respect to the Cd treated rats in Cd+CoQ10 partially are reversed changes (Cu,Zn SOD) of antioxidant defense system in the heart.
Impact of acquired and genetic factors on thrombophilic phenotype in FV Leiden mutation carriers
Authors: Djordjevic Valentina , Rakicevic Ljiljana , Miljic Predrag , Mikovic Danijela , Kovac Mirjana , Radojkovic Dragica , Savic Ana
Published: August 2005

FV Leiden mutation is an important genetic risk factor for venous thromboembolsm (VTE). In this study we have analyzed clinical manifestation and the impact of other genetic and acquired risk factors in 100 patients (95 heterozygous and 5 homozygous) carriers of FV Leiden mutation. Among these patients, 91 experienced VTE, with down limb deep vein thrombosis as the most frequent manifestation. An acquired risk factor was present in 68.6% of women, whereas this was the case in 28.6% of men. FIIG20210A was present in 9.5%, MTHFR 677TT in 8.4% and both mutations in 2.1% of the heterozygous FV Leiden carriers. Our results suggest that knowledge of coexisting factors predisposing to VTE is very important for FV Leiden mutation carriers and may contribute to the prevention of VTE episodes.
Thiophene based monoazo disperse dyes for polyester fabric
Authors: Maradiya Hari , Patel Vithal
Published: August 2005

A series of monoazo disperse dyes have been prepared by coupling 2-amino 3-carbethoxy-4,5-dimethylthiophene with various N-arylmaleimides. The monoazo disperse dyes were characterised by IR spectral studies and elemental analysis. These dyes were applied at 2%depth on polyester fabrics and gave light yellow to brown colour hues with fair fastness to light and very good to excellent fastness to washing, rubbing, perspiration and sublimation. The percentage exhaustion of the dyebath and fixation on the fabric were found to be very good.
The effect of reversing current deposition on the apparent density of electrolytic copper powder
Authors: Popov Konstantin , Pavlovic Ljubica , Ivanovic Evica , Radmilovic Velimir , Pavlovic Miomir
Published: August 2005

The possibility of depositing copper powders with different apparent density by changing the shape of reversing current wave is shown. The morphology and crystallinity of powder particles can be varied considerably by changing shape of the reversing current wave and, hence, the apparent density of powders. The relation of apparent density with particle morphology and structure was illustrated.
Ordering of alkane isomers by means of connectivity indices
Authors: Gutman Ivan , Vidovic Dusica , Nedic Anka
Published: August 2005

The connectivity index of an organic molecule whose molecular graph is Gis defined as C(?)=?(?u?v)??where ?u is the degree of the vertex u in G, where the summation goes over all pairs of adjacent vertices of G and where ? is a pertinently chosen exponent. The usual value of ? is ?1/2, in which case ?=C(?1/2) is referred to as the Randic index. The ordering of isomeric alkanes according to ??follows the extent of branching of the carbon-atom skeleton. We now study the ordering of the constitutional isomers of alkanes with 6 through 10 carbon atoms with respect to C(?) for various values of the parameter ?. This ordering significantly depends on ?. The difference between the orderings with respect to ??and with respect to C(?) is measured by a function ??and the ?-dependence of ??was established.
Theoretical consideration and application of the SP and SP' scales in RP chromatographic systems in which Everett’s equation is valid
Authors: Janjic Tomislav , Vuckovic Gordana , Celap Milenko
Published: August 2005

It is shown that in the case of ODS and less polar modifiers the log k values are a linear function of the SP?parameters. This findings differ from earlier investigated systems, in which a linear dependence between log k and SP parameters (SP = log SP?) was found. Both linear relationships have been analyzed and the corresponding possible separation mechanisms have been considered. In addition, the advantages of normalization of both scales are shown and how then they can be applied in the investigation of substances congenerity.
The synthesis and characterization of facial and meridional isomers of uns-cis-(ethylenediamine-N, N’-di-3-propionato)cobalt(III) complexes with S-lysine and S-histidine
Authors: Stamenovic Danijela , Trifunovic Srecko
Published: August 2005

In the reaction of sodium uns-cis-(ethylenediamine-N-N?-di-3-propionato)-(carbonato) cobaltate(III) dihydrate and the corresponding amino acid (S-lysine or S-histidine) at 70 ?C, both the theoretically possible facial and meridional isomers of the uns-cis-(ethylenediamine-N-N?-di-3-propionato)(aminoacidato)cobalt(III) complexes were prepared. The complexes were isolated chromatographically and characterized by elemental analyses, as well as by electron absorption and infrared spectroscopy.
The current distribution in an electrochemical cell. Part VII. Concluding remarks
Authors: Popov Konstantin , Pesic S.M. , Zivkovic Predrag
Published: August 2005

Anew method for the determination of the ability of an electrolyte to distribute uniformly current density in an electrochemical cell is proposed. It is based on the comparison of the current in cells in which the electrode edges touch the cell side walls with the current in cells with different electrode edge ? cell side wall distances. The effects of cell geometry process parameters and current density are discussed and illustrated using the results presented in the previous papers from this series.
An efficient synthesis of warfarin acetals on montmorillonite clay K-10 with microwaves
Authors: Krstic Ljubomir , Sukdolak Slobodan , Solujic-Sukdolak Slavica
Published: August 2005

The microwave promoted reaction of warfarin with methanol, or ethanol, in the presence of montmorillonite clay K-10 as a catalyst, affords the corresponding acetals, 2-methoxy 2-methyl-4-phenyl-3,4-dihydro-2H-pyrano[3,2-c]chromen-5-one (2) and 2-ethoxy-2-methyl- 4-phenyl-3,4-dihydro-2H-pyrano[3,2-c]chromen-5-one (3) respectively, in good yields.
Reductive deactivation of some s-triazine herbicides: Prometryne, desmetryne and terbutryne
Authors: Galvin Rrafael , Mellado Jose , Higuera Maria
Published: August 2005

The electrochemical behaviour (DC and DPpolarography) of the methylthio-bis(alkylamino) s-triazine herbicides prometryne, desmetryne and terbutryne on mercury electrodes has been studied in the acidity range 2.25MH2SO4 to pH 6.5. Two two-electron irreversible reduction processes were found, complicated with adsorption. At pH values higher than the protonation pKof the triazine ring (ca. 4), this protonation reaction preceded the reduction processes. Reduction mechanisms are proposed for pH < pK and pH > pK. The products obtained in the electroreduction of dilute solutions of the above herbicides show a lower toxicological effect than that of the original compounds (lower aromatic character and cleavage of the ?SCH3 group). Thus electrochemical deactivation at pH ??3.5 and at potentials around ?1.10 V (vs. the Ag/AgCl/KClsat electrode) can be a valid method to deactivate these molecules. Finally, the reductive route can be an alternative environmental degradative process in waters under strong reductive conditions, with pH values equal or lower than 3.5 pH-units, and rich in carbonaceous materials on clays. In these ambients oxidative photolytic detoxification of herbicides cannot occur.
Far-infrared spectroscopy of PbTe doped with iron
Authors: Nikolic Pantelija , Radulovic K. , Vasiljevic-Radovic D. , Blagojevic V. , Milosavljevic B. , Dohcevic-Mitrovic Zorana
Published: August 2005

Far infrared reflection spectra, at room and liquid nitrogen temperature, of PbTe single crystals doped with iron are presented. Plasma minima were observed at about 160 cm?1 and 180 cm?1 for room and liquid nitrogen temperature, respectively. Using the reflectivity diagrams and their minima the values of the hole concentrations and their mobility at both temperatures were calculated and compared with galvanomagnetic measurements. All these results indicated that when PbTe is doped with a small concentration of Fe, the hole concentration is reduced by one order of magnitude and the free carrier mobility is larger when compared to pure PbTe.
Isolation and partial characterization of an acid phosphatase from Artemisia vulgaris pollen extract
Authors: Cirkovic-Velickovic Tanja , Gavrovic-Jankulovic Marija , Bukilica Mirjana , Mandic Ljuba , Petrovic Spomenka , Jankov Ratko
Published: August 2005

An acid phosphatase from an extract of mugwort (Artemisia vulgaris) pollen was purified by a factor of 48 by a combination of ion exchange and gel-chromatography. The molecular weights of the enzyme were 76 kDa and 73 kDa, determined by gel filtration on a Sephadex G-100 sf column and by SDS PAGE(under reducing and non-reducing conditions), respectively. In analytical isoelectrofocusing, the enzyme appears as two very close bands pI at about 4.2. The optimum pH for the enzyme is 5.4. The apparent Km for p-nitrophenyl phosphate was estimated to be 0.16mM. The purified enzyme has broad specificity, and hydrolyses p-nitrophenyl phosphate and ?-naphthyl phosphate. Pyrophosphate and O-phospho-L-tyrosine were estimated to be the best substrates for this enzyme as potential in vivo substrates. The enzyme is inhibited competitively by phosphate (Ki = 1.25 mM), molybdate (Ki = 0.055 mM) and pyrophosphate (Ki = 6.7 mM) and non-competitively by fluoride (Ki = 9.8 mM). Metal ions such as Hg2+, Cu2+ and Zn2+ express an inhibitory effect on the enzyme, while the enzyme is slightly activated by non-ionic detergents, Tween 20 and Triton X-100. There is no change in the enzyme activity in the presence of tartrate, citrate, EDTA, 1,10-phenanthroline and sulfhydryl-group modifiers such as p-chloromercuribenzoate and N-ethylmaleimide.
Magnetic, thermal and spectroscopic properties of 5-chloro-2-methoxybenzoates of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II)
Authors: Bocian Beata , Ferenc Wieslawa
Published: August 2005

The 5-chloro-2-methoxybenzoates of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) were synthesized as solids and their magnetic, spectral and thermal properties studied. The complexes possess colours typical of the M(II) ions. The thermal stabilities were examined in air and nitrogen atmospheres and the products of decompositions were also identified. The magnetic susceptibilities of the complexes were measured over the temperature range 4.4?300 K and the magnetic moments were calculated. The results show that the 5-chloro-2-methoxybenzoates of Mn(II), Co(II) and Ni(II) are octahedral high-spin complexes.
Electrochemical deposition and characterization of zinc-nickel alloys deposited by direct and pulse current
Authors: Bajat Jelena , Maksimovic Miodrag , Radovic Goran
Published: August 2005

Chemical composition and phase structure of Zn-Ni alloys obtained by electrochemical deposition under various conditions were investigated. The alloys were deposited on a rotating disc electrode and steel panel from chloride solutions by direct and pulse current. The influence of the pulse plating variables (on-time, off-time, relation of off- and on-time) on the composition, phase structure and corrosion properties were investigated. The phase composition affects the anticorrosive properties of Zn-Ni alloys during exposure to a corrosive agent (3% NaCl solution). It was shown that a Zn-Ni alloy electrodeposited by pulse current with a pulse time of 1 ms and an off- and on-time ratio of 1 exhibits the best corrosion properties.
An estimation of the interfacial energy of the copper-copper sulphate solution interface and of the specific surface of copper powder
Authors: Popov Konstantin , Nikolic Nebojsa , Rakocevic Zlatko
Published: August 2005

Apossible way for the estimation of the interfacial energy of the copper ? copper sulphate solution interface is proposed. The estimated value of (2.7?0.3) J cm-2 and the derived equations which relate the specific surface of copper powder to the deposition conditions permit an estimation of the specific surface of copper powderc The agreement between the estimated value and literature data is very good.
Upgrading the Wiener index
Authors: Castro Eduardo , Gutman Ivan , Marino Damian , Peruzzo Pablo
Published: August 2005

The Wiener index Wis the oldest molecular-graph-based structure-descriptor. It is defined as the sum of the distances of all pairs of vertices of the molecular graph G, where the distance is the number of edges in the shortest path connecting the respective vertices, and where G is the hydrogen-depleted molecular graph. This seemingly very simple topological index could be "upgraded" (a) by using as the distance the sum of the bond lengths along the shortest path, or (b) by using the Euclidean distance between the respective pairs of atoms. Each of these "upgraded" Wiener indices could be computed either (?) for the hydrogen- depleted or (?) for the hydrogen-filled molecular graph. We provide examples showing that none of the modifications (a?), (a?), (b?), (b?) yields better results than the ordinary Wiener index, and that there is a very good linear correlation between W and its "upgraded" variants.
Spectrophotometric determination of trace iron(III) in natural water after its preconcentration with a chelating resin
Authors: Moldovan Zenovia , Neagu Eleonora-Ana
Published: August 2005

A method for the determination of Fe(III) at trace levels is described. Thus prior to the spectrophotometric determination, a preconcentration of the trace amounts of iron(III) using a chelate forming resin is proposed. A strong base anion-exchange resin (Dowex 2X4) loaded with Ferron (7-iodo-8-hydroxyquinoline-5-sulphonic acid) was used for Fe(III) preconcentration, at pH 2.2. After desorption with 5% ascorbic acid in 0.5 M HCl, the analyze (converted from Fe(III) to Fe(II) was determined spectrophotometrically at 510 nm as Fe(II)-o-phenanthroline complex. The accuracy of the proposed method was verified by comparing the obtained results with those obtained using AAS with the standard addition method. The sensitivity of the spectrophotometric method (after preconcentration) was 0.01?g Fe(III)/ml. The recovery for iron(III) at the 7?g/l level was 97%.
Disperse dyes based on 2-methyl-3-[3’-amino-phthalimido]-4(3H)-quinazilinone
Authors: Patel Vijay , Patel Manish.P. , Patel Ranjan
Published: August 2005

A series of new heterocyclic disperse dyes has been prepared by subsequent diazotization of 2-methyl-3-[3?-aminophthalimido]-4(3H)-quinazolinone and coupling with various mono- and di-N-substituted derivatives of aniline. All the disperse dyes were characterized by their percentage yield, melting point, UV-visible spectrum, elemental analysis, infrared spectrum and dyeing performance on nylon 66 and polyester fibres. The percentage dye bath exhaustion on different fibres was found to be reasonably good and acceptable. The dyed fibres showed fair to fairly good to good fastness to light and very good to excellent fastness to washing, rubbing, perspiration and sublimation.
Dielectric properties of some cadmium and mercury amino alcohol complexes at low temperatures
Authors: Masoud Mamdouh , Hafez Ahmed , Ramadan Sh.M. , Ali A.E.
Published: August 2005

The dielectric properties of some cadmium and mercury amino alcohol complexes were studied within the temperature range of 100?300 K at the frequencies of 100, 300 and 1000 kHz. The polarization mechanisms are suggested and the dependence of both ? and tg ? on both temperature and frequency are analyzed. The analysis of the data reveals semi-conducting features based mainly on the hopping mechanism.
Chemical constituents and antimicrobial activity of the ethanol extracts obtained from the flower, leaf and stem of Salvia officinalis L
Authors: Velickovic Dragan , Randjelovic Novica , Ristic Mihailo , Velickovic Ana , Smelcerovic Andrija
Published: August 2005

In this paper a comparison of the chemical composition and antimicrobial action of the ethanol extracts from the flower, leaf and stem of the herbal species Salvia officinalis L. (Lamiaceae), originating from the southeast region of Serbia was carried out. The chemical composition of the extracts was determined by GC-FID and GC-MS analyses. Manool has the highest level of all the components (9.0?11.1 %). Antimicrobial activity was determined by the diffusion and dilution method, whereby the latter one was modified by use of cellulose discs, and it was applied for the determination of the minimal inhibitory (MIC) and minimal lethal concentrations (MLC). The leaf extract has a stronger antimicrobial activity than those of the flower and stem.
Effect of substituents on the 13C-NMR chemical shifts of 3-methylene-4-substituted-1, 4-pentadienes - Part I
Authors: Valentic Natasa , Vitnik Zeljko , Kozhushkov Sergei , de Majere , Uscumlic Gordana , Juranic Ivan
Published: August 2005

The principles of linear free energy relationships were applied to the 13C substituent chemical shifts (SCS) of the carbon atoms in the unsaturated chain of 3-methylene-4-substituted-1,4-pentadienes. Correlations of the SCS with the substituent parameters of Swain and Lupton provide a mutually consistent picture of the electronic effects in these compounds. The pattern of the electronic effects can be fully rationalized by a model based on the direct transmission of substituent effects through-space (direct through-space field effects), and via conjugative interactions (resonance effects), or by substituent-induced polarization of the ?-system in the unsaturated chain (?-polarization effect). Semi-empirical MNDO-PM3 calculations suggest the s-cis conformation of 3-methylene-4-substituted-1,4-pentadienes as the one with minimal heat of formation.
Isomerization of an enzyme-coenzyme complex in yeast alcohol dehydrogenase-catalysed reactions
Authors: Leskovac Vladimir , Trivic Svetlana , Pericin Draginja
Published: August 2005

In this work, all the rate constants in the kinetic mechanism of the yeast alcohol dehydrogenase-catalyzed oxidation of ethanol by NAD+, at pH 7.0, 25 ?C, have been estimated. The determination of the individual rate constants was achieved by fitting the reaction progress curves to the experimental data, using the procedures of the FITSIM and KINSIM software package of Carl Frieden. This work is the first report in the literature showing the internal equilibrium constants for the isomerization of the enzyme-NAD+ complex in yeast alcohol dehydrogenase-catalyzed reactions.
Temperature effect on graphite KS44
Authors: Blizanac B. , Mentus Slavko , Cvjeticanin Nikola , Pavlovic N.
Published: August 2005

Graphite Lonza KS44 in a solution 1 M LiClO4 in a propoylene carbonate ethylene carbonate (1 M:1 M) mixture was lithiated and delithiated galvanostatically at room temperature and at the elevated temperature of 55 ?C. Voltage?time profiles and complex impedance diagrams were recorded and are discussed for this particular system. It was confirmed that this type of graphite shows a relatively small current loss consumed by exfoliation, if lithiated at room temperature. However, the voltage?time curve of the first charging at 55 ?C shows a long voltage plateau at 0.7 Vvs. Li/Li+, which corresponds to 540 mAh g-1 of irreversible capacity attributed to exfoliation. The solid electrolyte layer formed at elevated temperature although less protecting in the sense of electrolyte reduction, shows a remarkably higher electrical resistance than that formed at room temperature. A comparison of the impedance diagrams of lithiated and delithiated samples allows the conclusion that mass transfer through the graphite, not that through the solid electrolyte layer, plays a dominant role in the mass transfer limitations.
Retention behaviour of some estradiol derivatives on alumina in normal phase chromatrography
Authors: Acanski Marijana
Published: August 2005

The retention constants of variously substituted estradiol derivatives were measured as a function of the composition of various binary mobile phases in order to study the relationship between chemical structure and retention behavior in TLC on alumina. The slopes and intercepts of the linear relationships between the retention constant RM and the logarithm of the volume fraction of the polar mobile phase component were calculated and are discussed in relation to the characteristics of the solute and mobile phase. The RF values and relative retention ?RM of the compounds depend largely on the retention behavior of their substituents. The results obtained in this investigation are compared with the results of the same derivatives obtained in previous investigations on silica gel.
Separation of Y(dcta)- complexes from Nd(dcta)- and Sm(dcta)- complexes on polyacrylate anion-exchangers (Short communication)
Authors: Hubicka Halina , Kolodynska D.
Published: August 2005

The formation of anion rare earth element complexes with aminopolycarboxylic acids gives new possibilities for the separation of these elements on anion exchangers. The higher affinity of the Nd(dcta)- and Sm(dcta)- complexes for the anion- exchangers compared to Y(dcta)- complexes indicates the possibility of yttrium purification as a macrocomponent from the former by frontal analysis. The weakly basic polyacrylate gel anion-exchanger Amberlite IRA 68 was more effective in the purification of Y(III) from Nd(III) and Sm(III) complexes with DCTA than the strongly basic anion-exchangers of this type.
Antimalarial, antimycobacterial and antiproliferative activity of phenyl substituted mixed tetraoxanes
Authors: Opsenica Dejan , Dennis Kyle , Wilbur Milhous , Solaja Bogdan
Published: August 2005

Mixed tetraoxanes of the 4"-phenyl-substituted cyclohexyl-spirotetraoxacyclohexyl- spirocholate series have been prepared and evaluated as possible antimalarials, antiproliferatives and antimycobacterials. The activity of the (4"R or S)-phenyl series against P. falciparum D6 and W2 strains was found to be at the level of artemisinin with two compounds, the acid 4 and the amide 6, exhibiting encouraging anti-TB activity as well. Very promising in vitro results of the said tetraoxanes were obtained against solid tumours and, in some instances, the activity against a selected number of cell lines was higher than that of the antitumor drug Paclitaxel.
Synthesis of tetrahydrokhusitone: Annulation of the cyclohexane ring by free radical and carbanionic sequence of reactions
Authors: Petrovic Goran , Cekovic Zivorad
Published: August 2005

The synthesis of norcadinane sesquiterpene tetrahydrokhusitone 1 has been achieved by a new method for annulation of cyclohexane ring involving a sequence of free radical ?-alkylation of the non-activated carbon atom and intramolecular carbanionic alkylation. (?)-Menthol was used as the starting compound.
Wiener-type indices and internal molecular energy
Authors: Gutman Ivan , Vidovic Dusica , Furtula Boris , Zenkevich Igor
Published: August 2005

In earlier studies it was established that internal molecular energies (Eint) of alkanes can be reproduced, in an approximate yet reliable manner by means of a molecular-graph-based structure-descriptor U. It was also established that U is linearly correlated with the Wiener index W. We now show that the correlation between U and W is more complicated than earlier expected, and that it cannot be represented by a single line. We also show that a very good linear correlation exists between U and a modified version Wm(?) of the Wiener index, which is thus more suitable for modeling Eint than the ordinary Wiener index. .
The possibilities of the application of some species of sage (Salvia L) as auxiliaries in the treatment of some diseases
Authors: Velickovic Ana , Ristic Mihailo , Velickovic Dragan , Ilic Stevan , Mitic Natasa
Published: August 2005

The chemical composition of four essential oils of four species of sage (Salvia officinalis L., Salvia pratensis L., Salvia glutinosa L. and Salvia aethiopis L) are examined by GC-FID and GC-MS analysis. The presence of some components in the essential oil (mono- and sesquiterpene) determines the pharmacological effects and therapeutical application of a plant species. Salvia officinalis L. gives the highest yield of oil (1.1 %), while the lowest is in Salvia pratensis L. (0.1 %). The investigations included the determination of the antimicrobic activities of the essential oils by the diffusion method and the oil of Salvia pratensis L. proved to have the highest activity.
Thermodynamic and structural studies of complexes of manganese(II), cobalt( II), nickel(II) and copper(II) with aminofuropyridine carboxamide
Authors: Abd El
Published: August 2005

Complexes of Mn(II), Co(II), Ni(II) and Cu(II) with 2-aminofuro[3,2-b]pyridine- 3-carboxamide have been prepared. The stability constants of the formed complexes were determined at 20, 30, 40 and 50 ?C at a fixed ionic strength, I = 0.1 mol dm-3 (KCl). The values of the thermodynamic functions associated with complex formation were calculated and analyzed in terms of electrostatic and non-electrostatic components. The complexes were characterized with the help of chemical and spectral data.
Thermodynamic and kinetic behavior of hydrogen electrode in a solution of O. 5 M KClO4 in dimethyl sulphoxide
Authors: Vojinovic V. , Mentus Slavko , Komnenic V.
Published: August 2005

The hydrogen electrode on an interface platinum/dimethyl sulphoxide + 0.5 M KClO4 solution was examined from both the thermodynamic and kinetic aspect using HCl as a proton source. The equilibrium potential was shown to obey a Nernstian dependence on concentration. The voltammograms recorded using a rotating platinum disc electrode evidenced that the cathodic evolution of hydrogen proceeds under mixed, activation?diffusion control. The diffusion coefficient of the proton was determined to amount to 4.5x10-6 cm2s-1. In the region of activation control, a Tafel slope of about 0.110 V dec-1 was estimated, which indicates that the Volmer reaction is the rate determining step.
Experimental study of physical parameters significant in fullerene synthesis
Authors: Todorovic-Markovic Biljana , Markovic Z. , Marinkovic N. , Nenadovic Tomislav
Published: August 2005

In this work, the effect of physical parameters on the yield of fullerene synthesized in a hollow cathode plasma reactor is investigated. The experimental investigations done previously have shown that the fullerene yield depended on technical parameters - the current intensity, inert gas pressure, type of gas and interelectrode gap. The aim of this work was to show that the fullerene yield depends on physical parameters - carbon concentration, carbon flow rate from the interelectrode gap, axial temperature and temperature gradient between the are channel and the chamber walls as well. It was found that fullerene synthesis occurs in an inert heat bath with dimensions determined by the temperature gradient. The lower temperature limit is around 2000 K and the value of the upper limit is the value of the axis temperature which depends on the discharge conditions. The synthesis of fullerenes is more effective if the carbon concentration in the heat bath is large and the carbon flow rate from that zone to colder parts of chamber is small.
Equiseparable chemical trees
Authors: Gutman Ivan , Arsic Biljana , Furtula Boris
Published: August 2005

Let n1(e|T) and n2(e|T) denote the number of vertices of a tree T, lying on the two sides of the edge e. Let T1 and T2 be two trees with equal number of vertices, let e be an edge of T1 and f an edge of T2. Then e and f are said to be equiseparable if either n1(e|T1) = n1(f|T2) or n1(e|T1) = n2(f|T2). If all edges of T1 and T2 can be chosen so as to form equiseparable pairs, then T1 and T2 are equiseparable trees. A number of molecular structure-descriptors of equiseparable chemical trees coincide, implying that the corresponding alkane isomers must have similar physico-chemical properties. It is shown how equiseparable chemical trees can be constructed in a systematic manner. .
Bentonite, stabilizer for suspension polymerization
Authors: Koseva S. , Brezovska S. , Bosevska V. , Burevski D.
Published: August 2005

In suspension polymerizations, stabilizers play a crucial role in the particle formation. An effective stabilizer must be able to maintain complete coverage of the surface by both physical and/or anchoring adsorption. In this work the possibility of using original bentonite and bentonite with a high percentage of montmorillonite, their acid-activated and monocationic forms as mixed stabilizer has been investigated. Styrene was used as the monomer. Beads of polystyrene with spherical or elliptical shape were obtained, depending on form of the used bentonite. The results are discussed in terms of the acidity of the mineral surface, amphiphilic characteristic of the clay and the change of the contact angle between organic / water / mineral phase.
The current efficiency during the cathodic period of reversing current in copper powder deposition and the overall current efficiency
Authors: Pavlovic Miomir , Nikolic Nebojsa , Popov Konstantin
Published: August 2005

The current efficiency during the cathodic period of reversing current in copper powder deposition was determined by measuring the quantity of hydrogen evolved. The diagrams from which the instantaneous and average current efficiencies for copper deposition can be extracted for any deposition time up to 30 min are given. A procedure for the calculation of the overall current efficiency is proposed. .
Determination of uric acid in human serum by an enzymatic method using N-methyl-N-(4-aminophenyl)-3-methoxyaniline reagent
Authors: Jelikic-Stankov Milena , Djurdjevic Predrag , Stankov Dejan
Published: August 2005

In this work a new enzymatic method for the determination of uric acid in human serum has been developed. The method is based on the oxidative coupling reaction between the N-methyl-N-(4-aminophenyl)-3-methoxyaniline (NCP) reagent and the hydrogen ? donor reagent N-ethyl-N-(2-hydroxy-3-sulfopropyl)-3-methylaniline (TOOS), in the system involving three enzymes: uricase, peroxidase and ascorbate oxidase. Using this method uric acid could be determined in concentrations up to 1.428 mmol/L, with a relative standard deviation of up to 1.8 %. The effect of the medium pH and the NCP concentration on the linearity of the chromogen absorbance versus the uric acid concentration curve was investigated. The influence of the uricase activity on the maximum rate of uric acid oxidation was also examined. The use of the NCP reagent demonstrated a more precise and more sensitive determination of the uric acid compared to the determination with 4-aminoantipyrine (4-AA) as the coupling regent. The sensitivity of the method determined from the calibration curve was 0.71 absorbance units per mmol/L of uric acid; the limit of detection was LOD = 0.0035 mmol/L and the limit of quantification was LOQ = 0.015 mmol/L of uric acid.
Kinetic determination of As(III) in solution
Authors: Rancic Sofija , Igov Rangel , Pecev Todor
Published: August 2005

A new reaction is suggested and a new kinetic method is elaborated for the As(HI) traces determination in solution, on the basis of their catalyzing effect on komplexon III (EDTA) oxidation by KMnO4 in a strong acid solution (H2SO4). Using a spectrophotometric technique, a sensitivity of 72 ng/cm3 As(IIl) was achieved. The relative error of method varies from 5.5 to 13.9 % for As(HT) concentration range from 83 to 140 ng/cm-1. Appropriate kinetic equations are formulated and the influence of some other ions, including the As(V), upon the reaction rate is tested.
A formal synthesis of (+)-muricatacin from D-xylose
Authors: Popsavin Velimir , Grabez Sanja , Krstic Ivana , Popsavin Mirjana , Djokovic Dejan
Published: August 2005

A multistep route towards the aldehydo-lactone 19, the final chiral precursor in a new stereospecific synthesis of (+)-muricatacin, has been developed starting from D-xylose. The key step of the synthesis involves an E-selective Wittig olefination of the lactol 6 with methoxycarbonylmethylidene triphenylphosphorane, followed by successive catalytic reduction and ?-lactonisation processes. Subsequent selective functional groups interconver- sions furnished the key six-carbon intermediate 19, which can be converted into the (+)-muricatacin via a three-step sequence already described in the chemical literature.
Membrane-associated insulin-like growth factor (IGF) binding structures in placental cells
Authors: Masnikosa Romana , Nikolic-Judith Anna , Nedic Olgica
Published: August 2005

The biological activities of IGF-I and ?II are mediated mainly by the type 1 IGF receptor (IGF 1R) and controlled by their interaction with soluble proteins, the IGF binding proteins (IGFBPs). Although there is a growing body of evidence that some IGFBPs may be cell surface-bound, published data concerning cell association of IGFBP-1 are scarce and none of them concern placental cells. The cell membranes used in this study were isolated from term human placenta. Detergent-solubilized membranes were shown to contain two types of IGF binding structures that were separated by gel filtration on a Sephadex G-100 column. Proteins in the first peak were eluted at V0(Mr>100 kD) and they bound IGF-I with greater specificity and affinity than IGF-II and insulin. Most likely, they represented the IGF 1R. Small proteins (Mr?45 kD) were eluted with the membrane proteins in the second maximum. They were able to bind IGF-I and IGF-II, but not insulin. The identity of these proteins was shown to be IGFBP-1 on the basis of their reaction with specific anti-IGFBP-1 antibodies. To the best of our knowledge, the existence of IGFBP-1 associated with human placental cell membranes has not been reported in the literature before. Colocalisation of IGFBP-1 with IGF 1R in cell membranes could provide efficient modulation of IGF 1R receptor-ligand interactions.
Electrochemistry of active chromium, part III: Effects of temperature
Authors: Popic Jovan , Drazic Dragutin
Published: August 2005

It was shown that the temperature in the range 20 ? 65 ?C has considerable effects on the electrochemical anodic dissolution of chromium in the active potential range as well as on the electrochemical hydrogen evolution reactions on bare and oxide covered chromium surfaces. Also, the chemical dissolution of chromium is strongly affected. The apparent energy of activation for anodic dissolution is 63.1 kJ mol-1, for hydrogen evolution on a bare Cr surface 19.5 kJ mol-1, for the same reaction on an oxide covered surface 44.0 kJ mol-1 and for the chemical ("anomalous") dissolution 66.9 kJ mol-1. The temperature dependences of the total corrosion rate, and the electrochemical corrosion rate alone, are presented in polynomial forms with the appropriate constants obtained by the best fit of the experimental data. For the hydrogen evolution reaction on both bare and oxide covered chromium, the Volmer-Heyrovsky reaction mechanism with the second step as rate determining was proposed.
The apparent density as a function of the specific surface of copper powder and the shape of the particle size distribution curve
Authors: Popov Konstantin , Zivkovic Predrag , Krstic Snezana
Published: August 2005

The relation between the specific surface and apparent density of copper powders electrodeposited from acid copper sulfate solutions is established. It is shown that the apparent density is inversely proportional to the specific surface of copper powder. The shape of the particle size distribution curve is also discussed.
Utilization of Lavandula angustifolia Miller extracts as natural repellents, pharmaceutical and industrial auxiliaries
Authors: Yusufoglu Ayse , Çelik Hülya , Kirbsalar Gülay
Published: August 2005

Essential oils, absolutes and concretes were prepared from the flowers and leaves of the plant Lavandula angustifolia Miller cultivated in the Bosphorus region of Istanbul, Turkey. The difference in the chemical composition of the mentioned extracts was investigated and compared by using a combination of capillary GC-MS with the aim of offering them as repellent, pharmaceutical and industrial auxiliaries. The IR-spectra, the yields and the physico-chemical data of the extracts were also analyzed.
Preparation and properties of Cu(II) complexes with N,N’,N",N’’’-tetrakis(2-pyridylmethyl)-1,4,8,11-tetraazacyclotetradecane (tpmc) and pseudohalides(NCO- orNCSe-): Part II
Authors: Vuckovic Gordana , Miodragovic Zoran , Tanaskovic Sladjana
Published: August 2005

Two new Cu(II) complexes with N,N?,N",N???-tetrakis(2-pyridylmethyl) -1,4,8,11-tetraazacyclotetradecane (tpmc) and pseudohalides (NCO- or NCSe-) were isolated. Elemental analyses (C, H, N, Cu) corresponded to the formulas [Cu2(NCO)tpmc](ClO4)3. 2CH3CN and [Cu2(NCSe)2 tpmc] (ClO4)2. 2H2O. C2H5OH. The coordination mode of tpmc and these ambidentate pseudohalides, geometries spectral characteristics (VIS, IR) and other properties were compared with those of the previously described [Cu2(NCS)2tpmc] (ClO4)2. Antimicrobial activity towards selected bacteria and yeast was tested and found for the NCSe but not the NCO complex.
On the possible formation of Aurivillius phases in the oxide system Bi2O3-ZnO-Nb2O5
Authors: Rusu Iulian , Craus Mihail-Liviu , Sutiman Daniel , Rusu Alice
Published: August 2005

This paper presents results concerning the possible synthesis of double perovskite and Aurivillius phases in the BZN system. Acrystal chemical criterion based on an elastic model for the structure was used in order to determine if the formation of layered bismuth compounds is favoured in the above system. The tempeature seems to be the decisive factor influencing Aurivillius phase formation.
Synthesis of "in situ" reinforced silicon nitride composites
Authors: Vuckovic Aleksandra , Boskovic Snezana , Zivkovic Ljiljana
Published: August 2005

The objective of this work was to investigate the effect of two different sintering additives (CeO2 and Y2O3 + Al2O3), sintering time and amount of ?-Si3N4 seeds on the densification, mechanical properties and microstructure of self-reinforced Si3N4 based composites obtained by pressureless sintering. Preparation of ?-Si3N4 seeds, also obtained by a pressureless sintering procedure, is described. Samples without seeds were prepared for comparison. The results imply that self-reinforced silicon nitride based composites with densities close to the theoretical values and with fracture toughness of 9.3MPa m1/2 can be obtained using a presureless sintering procedure.
The structure directing role of 1, 3-diaminopropane in the hydrothermal synthesis of iron(III) phosphate
Authors: Rajic Nevenka , Stojakovic Djordje , Hanzel Darko , Kaucic Venceslav
Published: August 2005

1,3-Diaminopropane (DAP) was used as a structure-directing agent for the hydrothermal synthesis of an organically templated iron phosphate. During crystallization at 180 ?C, iron phosphate (FePO-DAP) with a layered structure was formed after one day. Longer crystallization yielded a mixture of FePO-DAP and leucophosphite, raising the question whether a transformation of FePO-DAP to leucophosphite occurs, or whether DAP decomposes under hydrothermal conditions resulting in leucophosphite formation. Lattice energy and free energy calculations strongly support the supposition that a decomposition of DAP occurs prior to the formation of leucophosphite.
The influence of the deposition parameters on the porosity of thin alumina films on steel
Authors: Lazic Marija , Simovic Kornelija , Miskovic-Stankovic Vesna , Jovanic Predrag , Kicevic Dusan
Published: August 2005

The influence of the deposition parameters on the porosity of thin alumina films electrophoretically deposited on steel from aqueous suspensions was investigated. The effects of the applied voltage, deposition time, suspension temperature and the solid content of the aqueous suspension on the porosity of the obtained alumina films have been determined using optical microscopy coupled with image analysis. It was shown that the lowest film porosity was obtained from a suspension containing 20 wt.% alumina powder at the lowest applied voltage (30 V), for a longer deposition time (10 min) using a suspension temperature of 30 ?C. This behavior can be explained by the smaller amount of hydrogen evolved on the cathode during the electrophoretic deposition process.
An expeditious synthesis of 3, 4-dihydro-benzo[2,3-d]pyrimidines using inorganic solid supports
Authors: Kidwai Mazaahir , Mishra Alkal
Published: August 2005

Aseries of novel 5-substituted-8-cyano-4,6,7-triphenyl-3,4-dihydrobenzo [2,3-d]pyrimidines were synthesized by the condensation of 6-substituted-2-amino 1-benzoyl-3-cyano-5-hydroxy-4,5-diphenyl-1,3-cyclohexadiene and formamide using inorganic solid supports under microwaves. Some of the compounds were found to be effective against some fungal and bacterial strains.
A facile synthesis of 10-methoxy-4. 8-dinitro-6H-benzo [2,3-c]chromen-6-one
Authors: Havaldar F.H. , Bhise S. , Burudkar S.
Published: August 2005

3-Methoxy-5-nitrobenzaldehyde undergoes Knoevenagel reaction with malonic acid to give 3-methoxy-5-nitrocinnamic acid (I). Treatment of I with thionyl chloride yielded 3-chloro-5-methoxy-7-nitrobenzo[b]thiophene-2-carbonyl chloride (II) in 45 % yield. The reaction of II with 2-nitrophenol in benzene gave 2-nitrophenyl 3-chloro-5-methoxy- 7-nitrobenzo[b]thiophene-2-carboxylate (IIIa) in 65 % yield. Finally, dehydrochlorinative photocyclization of IIIa in acetone in the presence of the base triethylamine afforded 10-methoxy-4,8-dinitro-6H-benzothieno_2,3-c_chromen-6-one (IVa). Thus, a series of derivatives IVa-i were synthesized in excellent yields. The structures of the obtained products were characterized by IR and 1H-NMR spectroscopy, as well as elemental analysis. Their purity was ascertained by chromatographic analysis. All the compounds were tested for their antibacterial activity against S. aureus, E. coli, B. subtilis and S. typhosa.
Ca(II) complexes of tetraazamacrocycles derived from 3, 4-hexenedione and diaminoalkanes
Authors: Prasad R.N. , Agrawal M. , Malhotra S.
Published: August 2005

Ca(II) macrocyclic complexes [(Et4[n]tetraeneN4)CaX2]?(where n = 14, 16, 20 24, 32, X = Cl-, NCS-) have been synthesized via cyclocondensation of 3,4-hexanedione with aliphatic diamines, such as 1,3-diaminopropane 1,4-diaminobutane, 1,6-diaminohexane, 1,8-diaminooctane or 1,12-diaminododecane. The synthesized complexes were characterized by elemental analyses, conductance measurements and IR and 1H-NMR spectroscopy.
The effect of diluents on the extraction of Sm(III) using N, N, N’, N’-tetrabutylmalonamide
Authors: Sun Guo-Xin , Cui Yu , Zhang Zhen-Wei , Xu Rong-Qi , Jiang Run-Tian , Sun Si-Xiu
Published: August 2005

A study has been made of the extraction of samarium(III) from nitrate solutions using N,N,N?,N?-tetrabutylmalonamide (TBMA) in a series of diluents. The dependence of the extraction distribution on the concentrations of aqueous nitric acid, lithium nitrate and organic TBMA was investigated. The experimental results showed that the extraction efficiency of TMBA in different diluents for Sm(III) increases in the order: chloroform, carbon tetrachloride, benzene, xylene, toluene, cyclohexane, n-hexane, n-octane. The stoichiometry of the extracted species conform to Sm(NO3)3.3TBMA in all the employed diluents. The interaction between extractant or extracted species and diluent is discussed and a quantitative expression relating the extraction constant and the parameters of the diluent has been established.
Separation of tungsten and rhenium on alumina
Authors: Vucina Jurij , Lukic Dagoljub , Stoiljkovic Milovan
Published: August 2005

The conditions for the efficient separation of tungsten(VI) and rhenium (VII) on alumina were established. The distribution coefficients K d for tungstate and perrhenate anions, as well as the separation factors ?(? = KdWO42-/Kd ReO4-) were determined using hydrochloric or nitric acid as the aqueous media. Asolution of sodium chloride in the pH range 2?6 was also examined. Under all the tested experimental conditions, alumina is a much better adsorbent for tungsten than for rhenium. The obtained results indicated that the best separation of these two elements is achieved when 0.01? 0.1 mol dm-3HCl or 1.0mol dm-3 HNO3 are used as the aqueous media. If NaCl is used as the aqueous phase, the best separation is achieved with 0.20 mol dm-3 NaCl pH 4?6. Under these experimental conditions, the breakthrough and saturation capacities of alumina for tungsten at pH4 are 17 and 26 mg W/g Al2O3 respectively. With increasing pH, these values decrease. Thus, at pH 6 they are only 4 and 13 mg W/g Al2O3, respectively.