JSCS Vol 69, No. 1
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Impresum |
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J.Serb.Chem.Soc.
69(1)1–7(2004) |
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Utilization of Lavandula angustifolia Miller extracts as naturalrepellents,
pharmaceutical and industrial auxiliaries
AYÔE YUSUFO˜LU, HÜLYA ÇELIK and F. GÜLAY KIRBAÔLAR
Department of Chemistry,
Faculty of Engineering, Istanbul University, 34850 Avcìlar, Istanbul, Turkey
(E-mail: hcelik@istanbul.edu.tr)
(Received 10 June 2002, revised 6 August 2003)
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 analysed.
Keywords: Lavandula angustifolia Miller, essential oil, absolute, concrete,
repellent, pharmaceutics, industrial.
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J.Serb.Chem.Soc.
69(1)9–16(2004) |
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Purification and partial characterization of
superoxide dismutase from the thermophilic bacteria Thermothrix sp.
SVETLANA SEATOVIC, LJUBINKA GLIGIC, ZELJKA RADULOVIC and RATKO M. JANKOV*
*Galenika a.d.,
Institute, Batajnicki drum b.b., 11080 Belgrade, Serbia and Montenegro and
**Faculty of Chemistry, University of Belgrade, Studentski trg 16, 11000
Belgrade, Serbia and Montenegro
(Received 20 June,
revised 8 August 2003)
Superoxide dismutase (SOD; EC 1.15.1.1.), a high
molecular weight component of the antioxidant defense system, provided
promising results in the treatment of oxidative dAMage. Thermothrix sp.,
isolated from thermal spa water in Serbia, showed high superoxide dismutase
activity. The SOD, from cell free extract, was purified to homogenity by
AMmonium sulfate precipitation, Sephadex G 75 gel filtration chromatography and
QAE Sephadex ion exchange chromatography. The specific activity of the purified
enzyme was 9191 U/mg. The purified enzyme was analyzed and partially
characterized. SOD was localized in polyacrylAMide gel by activity staining,
based on the reduction of nitroblue tetrazolium (NBT) by superoxide. The enzyme
molecular weight determined by gel chromatography is 37 kD. According to SDS
PAGE it is composed of two subunits of equal size, joined by noncovalent
interactions. The isoelectric point, assessed by isoelectric focusing is 5.3.
The optimum pH for enzyme activity was in the range of 8 to 10. The optimum
temperature for SOD activity was 60 ºC. After one hour of incubation at 40, 50
and 60 ºC the SOD activity increases, but at 80 ºC, the SOD is denaturated.
After 24 hours of incubation at 25 ºC SOD activity only slightly decreases.
Keywords: superoxide dismutase, Thermothrix sp., isolation, purification,
characterization.
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J.Serb.Chem.Soc.
69(1)17–23(2004) |
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Preparation and properties of Cu(II) complexes with N,N’,N",N’’’-tetrakis(2-pyridylmethyl)-1,4,8,11-tetraazacyclotetradecane
(tpmc) and pseudohalides (NCO- or NCSe-). Part II
GORDANA VUCKOVIC, ZORAN M. MIODRAGOVIC and SLADJANA TANASKOVIC*
Faculty of Chemistry,
University of Belgrade, P. O. Box 158, 11001 Belgrade and
*Faculty of Pharmacy,
University of Belgrade, Vojvode Stepe 450, 11000 Belgrade, Serbia and
Montenegro
(Received 11 June,
revised 2 September 2003)
Abstract: 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.
Keywords: copper(II) complexes,
octaazAMacrocycle, isocyanato ligand, isoselenocyanato ligand, antimicrobial
activity.
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J.Serb.Chem.Soc.
69(1)25–32(2004) |
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Investigation of the adsorption of anionic surfactants at different pH values
by means of active carbon and the kinetics of adsorption
SIBEL ZOR
Kocaeli University,
Faculty of Science and Arts, Department of Chemistry, 41300, Kocaeli, Turkey
(Received 14 April, revised 8 September 2003)
In this study, the effect of pH on the removal
of anionic surfactants, such as linear alkyl benzene sulfonate (LABS) and
dodecyl benzene sulfonate (DBS) by means of adsorption by activated carbon was
investigated. For this purpose activated carbon was used as adsorbent. Anionic
surfactant solutions with initial pH values of 3, 6, 8 and 12 were used. The
adsorption isotherms for the adsorption of anionic surfactants by active carbon
at different pH were determined. These adsorption isotherms were seen to be
consistent with Freundlich’s adsorption isotherm. k and n constants were
determined from Freundlich’s linear equation. Adsorption rate constants were
determined from the obtained kinetic curves which were suitable for the first
order of rate kinetics.
Keywords: surfactant, active carbon,
adsorption kinetics.
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Chaotic, mixed-mode and periodic oscillations during the electro-oxidation of
copper in trichloroacetic acid
LIANG LI*, SHENHAO CHEN*,**, HONGTAI WU*** and HAITAO CUIa*
*Department of Chemistry, Shandong University,
Jinan 250100, P. R. China
**State Key Laboratory for Corrosion and Protection, Shenyang 110015, P. R.
China and
***Material Evidence Test and Research Center of Shandong Province, Jinan
250100, P. R. China
(Received 26 May, revised
12 September 2003)
The current oscillations of a copper electrode
in trichloroacetic acid solutions were studied in this paper. The Cu/CCl3COOH
system is a new electrochemical oscillator, showing rich dynAMic behaviour on
two controllable parAMeters: the trichloroacetic acid concentration (cCCl3COOH) and the imposed
potential (E). Phase trajectories were reconstructed from time series
using time delay methods in order that the complex oscillations could be
analyzed. Five kinds of oscillations, periodic and quasiperiodic, mixed-mode,
aperiodic, small AMplitude and chaotic current oscillations, were observed. The
EDS (energy dispersive spectroscopy) technique was used to analyze the
elemental composition of the film formed on the surface of the copper electrode
after the current oscillations.
Keywords: current oscillations, copper,
trichloroacetic acid.
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The effect of the particle shape and structure on the flowability of
electrolytic copper powder.
III. A model of the surface of a representative particle of flowing copper
powder electrodeposited by reversing current
KONSTANTIN I. POPOV, SNEZANA B. KRSTIC, MILUTIN C. OBRADOVIC,
MIOMIR G. PAVLOVIC*, LJUBICA J. PAVLOVIC*
and EVICA R. IVANOVIC**
Faculty of Technology and Metallurgy, University
of Belgrade, Karnegijeva 4, 11000 Belgrade,
*ICTM-Department of Electrochemistry, Njegoseva 12, 11000 Belgrade and
**Faculty of Agriculture, University of Belgrade, Nemanjina 6, 11080
Zemun-Belgrade, Serbia and Montenegro
(Received 21 July 2003)
The structure of the surface of copper powder
particles is discussed and correlated with the lowest apparent density at which
copper powder can still flow. It is shown that such structures can be easily
obtained in the electrodeposition of powders in reversing current regimes.
Keywords: copper powder flowability, surface
structure of particles of flowing copper powder.
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J.Srb.Chem.Soc.
69(1)53–58(2004) |
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On the possible formation of Aurivillius phases in the oxide system Bi2O5–ZnO–Nb2O5
IULIAN RUSU, MIHAIL-LIVIU CRAUS*, DANIEL SUTIMAN and ALICE RUSU
Technical University “Gh. Asachi”, Faculty of
Industrial Chemistry, Bd. D. Mangeron 71, Iasi 6600 and
*National Institute for
Technical Physics, Bd. D. Mangeron 47, Iasi 6600, Romania
(Received 7 March,
revised 8 August 2003)
This paper presents results concerning the
possible synthesis of double perovskite and Aurivillius phases in the BZN
system. A crystal 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.
Keywords: synthesis, phase transition,
thermal analysis, XRD.
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J.Serb.Chem.Soc.
69 (1)59–67(2004) |
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Synthesis of “in situ” reinforced silicon nitride composites
ALEKSANDRA VUCKOVIC, SNEZANA BOSKOVIC and LJILJANA ZIVKOVI*
Materials Science Laboratory, Vinca Institute of
Nuclear Sciences, P. O. Box 522,11001 Belgrade and
*Faculty of Electronic
Engineering, University of Nis, Serbia and Montenegro
(Received 25 July 2003)
The objective of this work was to investigate
the effect of two different sintering additives (CeO2 and Y2O3
+ Al2O3), sintering time and AMount of b-Si3N4 seeds on the densification,
mechanical properties and microstructure of self-reinforced Si3N4
based composites obtained by pressureless sintering. Preparation of b-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 9.3 MPa m1/2 can be obtained using a
presureless sintering procedure.
Keywords: b-Si3N4
seeds, additive, pressureless sintering, self-reinforced composites,
densification, fracture toughness.
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J.Serb.Chem.Soc.
69(1)69–75(2004) |
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HPLC methods for the determinatiuon of acetyl-
and benzoyl-tiazofurin in rat plasma
LJILJANA PETROVIC, VESNA PIPERSKI, SLAVICA
RISTIC, JELENA TASIC, VESNA MATOVIC* and MILAN JOKANOVIC
1Galenika a.d.
Institute, Analytical and Stability Center, Batajnicki drum b.b., 11080 Zemun
and
*Faculty of Pharmacy, University of Belgrade, Vojvode Stepe 450, 11000
Belgrade, Serbia and Montenegro
(Received 13 May 2003)
Reverse-phase HPLC methods for determination of
5’-O-acetyl-tiazofurin (AT) and 5’-O-benzoyl-tiazofurin (BT) in rat
plasma were developed and validated in terms of specificity, linearity,
precision, accuracy and sensitivity. Linear calibration curves were constructed
in the concentration range of 2.50 – 100.00 mmol/L for both
compounds. The separations were achieved on a Supelcosyl LC-18-DB analytical
column (250×4.6 mm; 5 mm particle size) by
isocratic elution, with a mixture of 0.1 M disodium hydrogen phosphate –
methanol. UV detection was performed at a wavelength of 254 nm. The proposed
methods enable the detection and quantification of nanomolar concentrations of
AT and BT in rat plasma.
Keywords: HPLC, acetyl-tiazofurin,
benzoyl-tiazofurin, rat plasma
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J.Serb.Chem.Soc. 69(1)77–84(2004) |
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DynAMic holdup in a countercurrent gas - flowing
solids - packed bed contactors
NIKOLA M. NIKACEVIC, ALEKSANDAR P. DUDUKOVIC and
ZLATICA J. PREDOJEVIC
Faculty of Technology
and Metallurgy, University of Belgrade, Karnegijeva 4, 11000 Belgrade and
*Faculty of Technology, University of Novi Sad, Bul. cara Lazara 1, 21000 Novi
Sad, Serbia and Montenegro
(Received 25 June 2003)
Equations for the prediction of the holdup of
dynAMic solids in countercurrent gas – flowing solids – packed bed contactors
are presented in this paper. The correlations do not require the use of
parAMeters that need to be determined by experimental measurements in the
actual system of interest. They could be used for a wide range of operational
conditions, different packing types and a variety of flowing solids materials.
The equations are compared with all available experimental data from the
literature.
Keywords: multiphase contactors, gas –
flowing solids – packed bed contactors, gas – trickle solids flow, dynAMic
solids holdup.
Copyright &AMp; copy; SHD 2004.
February
3, 2004.
For
more information contact: SHD@tmf.bg.ac.yu