bluuebunny/crossref_metadata_2025 huggingface dataset:
On the relation between Zenkevich and Wiener indices of alkanes
Authors: Gutman Ivan , Furtula Boris , Arsic Biljana , Boskovic Zarko
Published: August 2005

A relatively complicated relation was found to exist between the quantity U recently introduced by Zenkevich (providing a measure of internal molecular energy), and the Wiener index W (measuring molecular surface area and intermolecular forces). We now report a detailed analysis of this relation and show that, in the case of alkanes, its main features are reproduced by the formula U = ??W + ? + ??1; where ?1 is the number of methyl groups, and ?, ? and ? are constants, depending only on the number of carbon atoms. Thus for isomeric alkanes with the same number of methyl groups, U and W are linearly correlated.
An approach to quantum chemical consideration of "hydride" transfer reaction
Authors: Pankratov Alexei , Drevko Boris
Published: August 2005

An approach to the quantum chemical study of "hydride ion" transfer has been proposed, according to which the sequences of changes in ionization potentials, enthalpies and free energies of the affinities to the hydride ion, to the hydrogen atom and to the proton of substrates molecules and their derivatives (cations, radicals, anions), are compared with the experimentally substantiated series of "hydride" mobility. It has been established that the experimental series of "hydride" mobility for six chalcogenopyrans based on "semicyclic" 1,5-diketones is in conformity with the computed ionization potentials of themolecules, and with the affinity of the corresponding radicals to the hydrogen atom involved in the transfer. The direct splitting-out of the hydride ion and the primary deprotonation of the substrates followed by the withdrawal of two electrons was elucidated to be unlikely. Feasible are the mechanisms of "hydride" mobility, the first step of which consists of electron or hydrogen atom transfer from the chalcogenopyrans molecules.
Kinetic determination of morin nanoamounts
Authors: Kostic Danijela , Mitic Snezana , Miletic Gordana
Published: August 2005

kinetic-spectrophotometric method is proposed for the determination of morin. The method is based on the inhibition effect of morin on the oxidation of C6H5COON aby hydrogen peroxide in the presence of the complex Fe(II)-AA(ascorbic acid),which acts as a catalyst. The concentration range for the determination of morin is one of the lowest achieved so far (a linear calibration graph was obtained for morin from 2.255?22.55 ng cm-3). The limit of detection of the method is 0.28 ng cm-3. The relative error ranges between 1.42 to 5.10% for the given concentration interval. Kinetic equations are proposed for the investigated process. The effects of certain foreign ions upon the reaction rate were determined in order to assess the selectivity of the method. The major advantages of this kinetic-spectrophotometric assay are its sensitivity, selectivity, reproducibility, speed and simplicity.
Spectrophotometric investigation of famotidine-Pd(II) complex and its analytical application in drug analysis
Authors: Koricanac Zagorka , Jovanovic Tatijana , Petkovic Jelena , Minic-Popovic Dragica
Published: August 2005

By using different spectrophotometric methods, it was found that famotidine and palladium(II) ions form a complex, Pd(II): famotidine = 1:1, which has an absorptionmaximum at 345 nm. The formation of the complex between famotidine and palladium(II) chloride in Britton?Robinson buffer solution in the pH range 2.23?8.50 was studied. The conditional stability constant of the complex at the optimum pH 2.62 and ionic strength 0.5M was found to be log K?= 3.742 ??0.025. The Beer?s law was verified over the famotidine concentration range from 5x10-5?6x10-4 M. The proposed method was found to be suitable for accurate and sensitive analysis of famotidine both as the substance (RSD = 1.02?1.80 %) and its dosage forms (RSD = 1.75?1.83 %).
The synthesis and preliminary pharmacological evaluation of racemic cis and trans 3-alkylfentanyl analogues
Authors: Ivanovic Milovan , Micovic I.V. , Vuckovic Sonja , Prostran Milica , Todorovic Zoran , Kricojevic V.D. , Djordjevic J.B. , Dosen-Micovic Ljiljana
Published: August 2005

A general, five step method for the synthesis of 3-alkylfentanyl analogues (i.e., cis and trans 3-alkyl-4-anilidopiperidines 6.1?6.6) has been developed. The starting N-phenethyl- 4-piperidone 1 was first converted into the cyclohexylimine derivative 2, ?-deprotonated with butyllithium and the resulting imine anion efficiently monoalkylated with primary and secondary alkyl halides. After mild acid hydrolysis, the obtained 3-alkyl-4-piperidones 3.1?3.6 were isolated in good yields (79?85 %), then condensed with aniline to form imines 4.1?4.6. Subsequent reduction of the imines (LiAlH4/THF) yielded cis/trans mixtures of 3-alkyl-4-anilinopiperidines 5.1?5.6. Quantitative separation of the diastereoisomers by column chromatography of Al2O3 gave pure cis 5.1?5.6 (29?51 % yield) and trans 5.1?5.6 (19?27%yield) with the cis/trans ratio in the range 7/3?6/4. The synthesiswas concluded by N-acylation of the purified 5.1?5.6, with propionyl chloride, to afford cis and trans 3-alkyl- 4-anilidopiperidines 6.1?6.6 (? 95 % yield, as monooxalate salts). No enatioseparation was attempted at any stage. The relative cis/trans stereochemistry was provisionally assigned from the 1H-NMR spectra. Of the twelve synthesized 3-alkylfentanyls, ten compounds (two known and eight novel derivatives, all as the monooxalate salts) were preliminarily tested as analgesics in rats, comparing the potency to fentanyl. Except for the known (?)-cis-3-Me fentanyl 6.1cis, (8 x fentanyl), and the novel (?)-cis-3-Et fentanyl 6.2 cis, (1.5 x fentanyl), all of the others were less active than fentanyl or inactive. Some tentative conclusions on the structure- activity relationship (SAR) in this series of derivatives have been made.
Equienergetic chemical trees
Authors: Brankov Vladimir , Stevanovic Dragan , Gutman Ivan
Published: August 2005

The energy E(G) of a graph G is the sum of the absolute values of the eigenvalues of G. Two graphs, G 1 and G 2, are said to be equienergetic if E(G 1) = E(G 2).We report here the results of the search for pairs of equienergetic acyclic molecular graphs (chemical trees) with the same number n of vertices. There are very few such pairs. The smallest has n = 9 and pertains to 3,3-diethylpentane and 3-methyloctane. Among the chemical trees with n ? 18, only five more such pairs and a triplet were found.
Cretaceous-Tertiary boundary deposits in Denmark: A diachroneity
Authors: Premovic Pavle
Published: August 2005

The lateral distribution of predominantly terrestrial kerogen or humics enriched with copper(II) porphyrins (Cu-P) across the Danish marine basin implies that the alleged Cretaceous-Tertiary (KT) boundary deposits in western Denmark (at the Nye Kl?v/Dania locations)were probably formed by erosion/emplacement of the boundary clay (Fiskeler) in eastern Denmark by marine currents, as originally proposed by Hulteberg.1,2.
Interpretation of Serbian surface sediment maturation parameters based on factor analysis
Authors: Sainovic Aleksandar , Stojanovic Ksenija , Filipovic Ivan , Cvetkovic Olga , Jovancicevic Branimir , Vitorovic Dragomir
Published: August 2005

The factor analysis, used in this work for the interpretation of maturation parameters observed in an exploration study of a group of surface sediments of diverse age originating from different localities in Serbia, resulted in two significant factors. Factor 1 involved parameters related mainly to maturation changes within the aliphatic chains of the organic matter and factor 2 involved parameters based mainly on changes in the terpane and sterane rings. A statistically significant inversely proportional linear dependence between factors 1 and 2 was observed with older, in contrast to younger sediments, suggesting that the reactions of the aliphatic chains in the older sediments did not occur simultaneously with the reactions in the rings and, also, that the older surface sediments examined in this study may be characterized by a degree of thermal maturity corresponding to changes in the biomarker sterane and terpane rings, while the younger sediments by intensive changes in the aliphatic chains.
MS analysis of biindenylidenes
Authors: Sinadinovic-Fiser Snezana , Jovanovic Jovan
Published: August 2005

Biindenylidene isomers are components of pyrolysis oils. The mass spectra were recorded and the fragmentation of the following biindenylidene isomers (E)-2,3,2?,3?-tetrahydro- [1,1?]biindenylidene (Z)-2,3,2?,3?-tetrahydro-[1,1?]biindenylidene 1,3,1?,3?-tetrahydro-[2,2?]biindenylidene and 2,3,1?,3?-tetrahydro-[1,2?]biindenylidene, as well as of spiro[1,1a,6,6a-tetrahydrocyclopropa [a]indene-1,1?-2?,3?-dihydro-1?H-indene]?is discussed.
Temperature dependence of the Kovats retention indices for alkyl 1, 3-diketones on a DB-5 capillary column
Authors: Mijin Dusan , Antonovic Dusan
Published: August 2005

A series of alkyl 1,3-diketones were used to study the temperature dependence of the Kovats retention indices in the temperature range 130?190 ?C (403?463 K). The temperature dependence is described by the empirical equation I = B B/T + ClnT. On the basis of this equation, the activation enthalpy, ?H?, and the chemical potential of the partitioning of one methylene group between the two phases of the chromatographic system, ??p(CH2), were calculated. Also the Kovats retention indices ? boiling point correlations (linear and reciprocal) for alkyl 1,3-diketones were studied and ??p(CH2) was calculated.
Synthesis of a steroidal dendrimer core
Authors: Kop Tatjana , Pocsfalvi Gabriella , Solaja Bogdan
Published: August 2005

Synthesis of a steroidal dendrimer core possessing various functional termini, such as ester, carboxy and hydroxy, is presented. The approach described enables further simple manipulations for the introduction of more complex functionalities.
Synthesis of the 4’-desmethoxy analogue of RU79115
Authors: Musicki Branislav , Periers Anne-Marie , Tessot Nicole , Klich Michel
Published: August 2005

The synthesis, and biological activity in vitro of the 4?-desmethoxy analogue (3) of RU 79115 (2) is described. Comparison of the biological activity of the two analogues clearly indicated the importance of the 4?-methoxy group in conferring good gyrase B inhibitory activity as well as antibacterial activity.
Preserved precursors in Pumpherston shale ketogen revealed by oxidative degradation
Authors: Bajc Snezana , Amblès A. , Vitorovic Dragomir
Published: August 2005

An optimised stepwise alkaline permanganate degradation was shown to have potentials in elucidating the genesis pathway and the origin of kerogens and, more specifically, to reveal preserved precursors in a kerogen matrix. Thus, Pumpherston shale kerogen, used as the substrate in this study, was found to be of mixed origin, i.e., to contain both inherited resistant algal structures (B. braunii Aand B algaenans), as well as resistant biomacromolecular components of continental flora (cutans). It is suggested that this kerogen or parts of it were formed by the selective preservation pathway.
Nickel(II) cyclohexylethyl-dithiocarbamate P-donor ligands in the coordination sphere
Authors: Husárek Josef , Pstorek Richard , Malon Michal , Sindalar Zedenek , Pavlícek Marek
Published: August 2005

A series of new Ni(II) dithiocarbamate compounds of the composition [NiX(cetdtc)(PR3)](X = Cl, Br, I, NCS; cetdtc = cyclohexylethyldithiocarbamate; R = phenyl, n-butyl) has been synthesized. All the isolated complexes have been characterized by elemental analysis, IR and UV/VIS spectroscopy, 31P{1H}-NMR spectroscopy, thermal analysis magnetochemical and conductivity measurements. On the basis of the results of the physico-chemical study, all complexes are diamagnetic, non-electrolytes with a square-planar NiS2PX chromophore.
The correlation of the values of plant-available lead and cadmium in soil determined using different types of extragents
Authors: Savin Ankica , Veselinovic Dragan , Markovic Dragan
Published: August 2005

The plant-available amount of Pb and Cd in soil was determined by extraction using the solutions: 1) 0.5MNa2EDTA, pH5.2; 2)1M KCl, pH7.0; 3)0.1M KCl, 0.05 MNa2EDTA, pH 6.2; 4) 2 % CH3COOH, pH 2.5 and 5) 1M CH3COONH4, pH 4.8. Chernozem and hydromorphic black soil types from the Middle Banat were used. It can be concluded that the values of the plant-available amounts of Pb and Cd in a soil depends on the stability constants of their complexes with ligands in the extraction solution. The conversion factors for the recalculation of the amounts of Pb and Cd obtained using the citted extractants have been calculated.
The geometrical isomers of oxalato and malonato-(ethylenediamine-N,N’-di-S,S-2-propionato)-chromate(III) complexes
Authors: Glodjovic Verica , Joksovic Milan , Trifunovic Srecko
Published: August 2005

Three octahedral chromium(III) complexes of the general formula Na[Cr(S,S-eddp)L].2H2O, where eddp = the tetradentate O-N-N-O-type ligand ethylenediamine-N,N?-di-S,S-2-propionate and L = a bidentate O-O-type ligand, either oxalate or malonate, were prepared. The complexes were synthesized by the reaction of chromium(III) chloride, S,S-eddp and malonic acid or sodium oxalate, at 60?C. The complexes were isolated chromatographically and the geometric configuration of the complexes was proposed on the basis of their infrared and electronic absorption spectra.
Characterization of carbon cryogels synthesized by sol-gel polycondensation
Authors: Babic Biljana , Djokic Divna , Krstajic Nedeljko
Published: August 2005

Resorcinol-formaldehyde (RF) cryogels were synthesized by the sol-gel polycondensation of resorcinol (R) with formaldehyde (F) and freeze-drying was carried out with t-butanol. Carbon cryogels were obtained by pyrolyzing RF cryogels in an inert atmosphere. Characterization by nitrogen adsorption showed that the carbon cryogels were micro and mesoporous materials with high specific surface areas (SBET ? 550 m2/g). Cyclic voltammeter experiments at various scan rates (2 to 200 mV s-1) were performed to study the electrical double-layer charging of carbon cryogel electrodes in 0.5 mol dm-3 HClO4 solution. It has been demonstrated that it is possible to sub-divide the total specific capacitance into the mesoporous and the microporous specific capacitance by analyzing the linear dependence of the charge (q) on the reciprocal of the square root of the potential scan rate (?-1/2), and the linear dependence of the reciprocal charge (1/q) on the square root of the potential scan rate (?-1/2). The specific capacitance was found to be constant over a wide range of sample weight (12.5 to 50.0 _g) and a very promising specific capacitance value of 150 F/g, was found for this material operating in an acidic 0.5 mol dm-3 HClO4 solution at room temperature.
Adsorption properties and porous structure of sulfuric acid treated bentonites determined by the adsorption isotherms of benzene vapor
Authors: Brezovska Snezana , Marina Biljana , Burevski Donco , Angjuseva Biljana , Bosevska Vasa , Stojanovska Lepa
Published: August 2005

In a previous paper, adsorption isotherms of benzene vapor on natural bentonite from Ginovci, Macedonia, and forms acid activated with 10% and 15% solutions of hydrochloric were interpreted by means of the Dubinin-Radushkevich-Stoeckli and Dubinin-Astakhov equations; the investigation has been continued with bentonites acid activated with 10% and 15% solutions of sulfuric acid where X-ray analysis indicates smaller structural changes. Using the above equations, the heterogeneity of the micropores and the energetic heterogeneity of the bentonites were determined from the differential distribution of the micropore volume with respect to the structural parameter of the equations characterizing the microporous structure and to the molar free energy of adsorption. Activated bentonites obtain bigger pores but also a certain quantity of new small pores appear during acid activation with the higher concentration of acid. The micropore volumes, determined from the adsorption of benzene vapor, of bentonites activated with 10 % and 15 % solution of hydrochloric acid (144.60 cm3 kg-1 and 110.06 cm3 kg-1, respectively), decrease in comparison with that of natural bentonite (162.55 cm3 kg-1). In contrast, the values of the micropore volume for bentonities treated with 10 % and 15 % solutions of sulfuric acids increase (169.19 cm3 kg-1 and 227.74 cm3 kg-1). That is due to the difference in the structural changes occurring during activation with hydrochloric and sulfuric acids. The values of the free energy of adsorption of benzene vapor for natural bentonite are higher than those of the acid activated bentonities, what is in accordance with the structural and porosity changes.
The surface energy of disperse cadmium electrodeposits formations
Authors: Zivkovic Predrag , Popov Konstantin
Published: August 2005

The surface energy of disperse cadmium electrodeposits formation was determined by using a procedure described earlier.1,2 It was shown that the surface energy strongly depends on the composition of the solution from which the deposition was carried out.
Optical diagnostics of fullerene synthesis in the RF thermal plasma process
Authors: Todorovic-Markovic Biljana , Markovic Zoran , Mohai I. , Károly Z. , Farkas Z. , Nikolic Z. , Szépvölgyi J.
Published: August 2005

In this work, the results of an optical emission study of fullerene synthesis in an inductively coupled radio frequency thermal plasma reactor are presented. The emission spectroscopy studies, based on the use of the Swan C2 (0,1) and CN (0,0) vibration emission spectra, were carried out to determine the plasma temperature. The evaporation process of graphite powder was observed by scanning electron microscopy.
Mathematical modeling and simulation of gel drying with supercritical carbon dioxide
Authors: Orlovic Aleksandar , Petrovic Stojan , Skala Dejan
Published: August 2005

Mathematical models of alumina/silica gel supercritical drying with carbon dioxide were studied using supercritical drying experimental data. An alumina/silica gel with zinc chloride was synthesized and dried with superciritical carbon dioxide, and its weight change was monitored as a function of drying time. The pore size distribution of the obtained aerogel was determined using the BET method and nitrogen adsorption/ desorption. The mathematical model of the supercritical drying of the wet gel was represented as unsteady and one-dimensional diffusion of solvent through the aerogel pores filled with supercitical carbon dioxide. Parallel pore model and pores in series model were developed on the basis of the measured porous structure of the aerogel. It was found that these models which use different effective diffusivity value for each pore size were in much better agreement with the experimental data than models which use an overall effective diffusivity. The local effective diffusivity coefficients were calculated using different tortuosity values for each pore size, and they were distributed according to the pore size distribution data. Model simulations of the superciritical drying with carbon dioxide confirmed that the drying temperature and gel particle diameter have a significant influence on the drying time.
Exchange between the stagnant and flowing zone in gas-flowing solids-fixed bed contactors
Authors: Dudukovic Aleksandar , Nikacevic Nikola , Pjanovic Rada , Kuzeljevic Zeljko
Published: August 2005

In countercurrent gas - flowing solids - fixed bed contactors, a fraction of the flowing solids is in motion (dynamic holdup), while the other fraction is resting on the fixed bed elements. In this study it was experimentally proved that the stagnant zone should not be considered as a dead part of the column, but that there is a dynamic exchange between these two portions of flowing solids particles. Combining a mathematical model with tracer experiments, the rate of exchange was determined and it was shown that only a small part (ca. 20 %) of the stagnant region should be considered as a dead one.
A water-soluble triiodo amino acid and its dendrimer conjugate for computerized tomography (CT) imaging
Authors: Yordanov Alexander , Mollov Nikolay , Lodder Adriana , Woller Eric , Cloninger Mary , Walbridge Stuart , Milenic Diane , Brechbiel Martin
Published: August 2005

Prolonging the circulation of an imaging agent is vital for making it suitable for blood pool (vascular) imaging. Medical applications of vascular imaging include cardiovascular disease, abnormal capillary permeability, and tumor neovascularity. As low molecular weight computerized tomography (CT) enhancement agents are characterized by inconveniently fast clearance, macromolecular compounds (both natural and synthetic) have gained a wide recognition for possessing better characteristics for performing blood imaging tasks. Herein, the syntheses and characterization of a new water-soluble triiodo amino acid, 3-[(N,N-dimethylaminoacetyl) amino]-?-ethyl-2,4,6-triiodobenzenepropanoic acid (DMAA-IPA) and its Starburst PAMAM generation 4.0 dendrimer conjugate, G-4-(DMAA-IPA)37 are described. The applicability of G-4-(DMAA-IPA)37 as a potential macromolecular angiographic CT contrast agent is discussed. The linear relationship between organically bound iodine concentration and CT Hounsfield units has been established thus allowing for quantification uses of CT imaging as well.
On the occurrence of sonchuside A in Cicerbita alpina and its chemosystematic significance
Authors: Zidorn Christian , Schwaha Ritae , Ellmerer Ernst , Stuppner Hermann
Published: August 2005

The subaerial parts of Cicerbita alpina yielded the guaianolide 8-acetyl- 15?-D-glucopyranosyllactucin (1) and the germacranolide Sonchuside A (2). The sonchuside A is reported for the first time from the genus Cicerbita. 1H-NMR and 13C NMR data of compounds 1 and 2 measured in deuterodimethyl sulfoxide and deuteromethanol, respectively, are given and the chemosystematic implications of the occurrence of sonchuside A in C. alpina are discussed briefly.
Study of gold-platinum and platinum-gold surface modification and its influence on hydrogen evolution and oxygen reduction
Authors: Desic Maja , Popovic Milica , Obradovic Maja , Vracar Ljiljana , Grgur Branimir
Published: August 2005

Surface modification of the electrodes was conducted from sulfuric acid solutions containing the corresponding metal-chloride complexes using cyclic voltammeter. Comparing the charges of the hydrogen underpotential deposition region, and the corresponding oxide reduction regions, it is concluded that a platinum overlayer on gold forms 3D islands, while gold on platinum forms 2D islands. Foreign metals present in an amount of up to one monolayer exert an influence on the change in reaction rate with respect to both hydrogen evolution (HER) and oxygen reduction (ORR) reactions. Aplatinum overlayer on a gold substrate increases the activity for HER and for ORR, compared with pure gold. These results can be understood in terms of a simple model, in which the change in the H and OH binding energies are directly proportional to the shift of the d-bond center of the overlayer. On the contrary, a gold layer on platinum slightly decreases the activity for both reactions compared with pure platinum.
Metal complexes with Schiff-base ligands - pyridoxal and semicarbazide-based derivatives
Authors: Leovac Vukadin , Jevtovic Violeta , Jovanovic Ljiljana , Bogdanovic Goran
Published: August 2005

The most important results of extensive studies (syntheses, spectral, magnetic, voltammetric and structural characteristics and biological activity) of metal complexes with pyridoxal semi-, thiosemi- and isothiosemicarbazones are reviewed.
Vapour-liquid equilibrium of the OPLS, optimized potentials for liquid simulations, model for binary systems of alkanes and alkanes + alcohols
Authors: Serbanovic Slobodan , Mijajlovic Milan , Radovic Ivona , Djordjevic Bojan , Kijevcanin Mirjana , Djordjevic Emila , Tasic Aleksandar
Published: August 2005

The NpT - Gibbs ensemble Monte Carlo computer simulation method was applied to predict the vapour-liquid equilibrium (VLE) behavior of the binary systems ethane + pentane at 277.55 K and 310.95 K, ethane + hexane at 298.15 K, propane + methanol at 313.15 K and propane + ethanol at 325.15 K and 425.15 K. The optimized potentials for the liquid simulating (OPLS) model were used to describe the interactions of alkanes and alcohols. The simulated VLE predictions are compared with experimental data available for the pressure and phase composition of the analyzed binary systems. The agreement between the experimental data and the simulation results is found to be generally good, although slightly better for system in which both components were nonpolar.
Manganese superoxide dismutase (MnSOD) catalyzes NO-dependent tyrosine residue nitration
Authors: Stojanovic Srdjan , Stanic Dragana , Nikolic Milan , Raicevic Smiljana , Spasic Mihajlo , Niketic Vesna
Published: August 2005

The peroxynitrite-induced nitration of manganese superoxide dismutase (MnSOD) tyrosine residue, which causes enzyme inactivation, is well established. This led to suggestions that MnSOD nitration and inactivation in vivo, detected in various diseases associated with oxidative stress and overproduction of nitric monoxide (NO), conditions which favor peroxynitrite formation, is also caused by peroxynitrite. However, our previous in vitro study demonstrated that exposure of MnSOD to NO led to NO conversion into nitrosonium (NO+) and nitroxyl (NO?) species, which caused enzyme modifications and inactivation. Here it is reported that MnSOD is tyrosine nitrated upon exposure to NO, as well as that MnSOD nitration contributes to inactivation of the enzyme. Collectively, these observations provide a compelling argument supporting the generation of nitrating species in MnSOD exposed to NO and shed a new light on MnSOD tyrosine nitration and inactivation in vivo. This may represent a novel mechanism by which MnSOD protects cell from deleterious effects associated with overproduction of NO. However, extensive MnSOD modification and inactivation associated with prolonged exposure to NO will amplify the toxic effects caused by increased cell superoxide and NO levels.
Cobalt(II) complexes of tetraazamacrocycles derived from β-diketones and diaminoalkanes
Authors: Prasad R.N. , Agrawal Mithlesh , Sharma Sanjna
Published: August 2005

Co(II) complexes of the type [Co(L)(NO3)2] (L = tetraazamacrocycle with 18 to 34-membered ring) were synthesized by the template condensation of ?-diketones, such as 2,4-pentanedione, 1-phenyl-1,3-butanedione or 1,3-diphenyl-1,3-propanedione, with diaminoalkanes. The complexes were characterized by elemental analyses, molar conductances and magnetic moments measurements, as well as infra red and electronic spectroscopy.
Functional Screening in the Melanophore Bioassay
Authors: Jayawickreme Channa , Sauls Howard , Watson Chris , Moncol David , Rimele Thomas , Kenakin Terry
Published: August 2005

The melanophore bioassay is a robust, sensitive, and versatile procedure for screening G
protein–coupled receptors in a variety of formats. Because melanophores contain a wide variety of G
proteins, they can be employed as a sensitive, real‐time response system for studying transfected
receptors and for defining equilibria for drug effects. This assay can be run in 96‐well microtiter
plates or in open‐lawn 1536 format, and can yield conventional agonist‐antagonist as well as
constitutive assays.
Isolation of Murine Hematopoietic Stem Cells and Progenitor Cells
Authors: Ema Hideo , Morita Yohei , Nakauchi Hiromitsu , Matsuzaki Yumi
Published: August 2005

Protocols for the purification of CD34−KSL cells, CD34+KSL cells, SP cells, and Tip‐SP CD34−KSL cells are described. Mouse hematopoietic stem cells are highly enriched in the CD34−KSL and SP fractions. These two populations overlap one another. A nearly homogenous population of HSCs can be obtained by isolating Tip‐SP CD34−KSL cells. One of the earliest progenitor cell populations is CD34+KSL cells.
Differentiation of Peripheral Blood Monocytes into Dendritic Cells
Authors: O'Neill David W. , Bhardwaj Nina
Published: August 2005

Dendritic cells (DCs) are potent antigen‐presenting cells (APC) that are important in the initiation and control of cellular immune responses. Commonly used in T cell–stimulation experiments, DCs are typically “matured” in vitro with microbial products or proinflammatory cytokines, and then loaded with antigens from any number of sources, including peptides, whole proteins, cell lysates, RNA, microbes, or killed tumor cells. This unit presents a simple and commonly used method for the generation of mature human dendritic cells—differentiating them from peripheral blood monocytes.
Rhodium Complexes Non‐Covalently Bound to Cyclodextrins: Novel Water‐Soluble Supramolecular Catalysts for the Biphasic Hydroformylation of Higher Olefins
Authors: Sueur Benoît , Leclercq Loïc , Sauthier Mathieu , Castanet Yves , Mortreux André , Bricout Hervé , Tilloy Sébastien , Monflier Eric
Published: August 2005

A new class of cationic α‐cyclodextrins bearing 2‐hydroxy‐3‐trimethylammoniopropyl groups has been synthesised. We investigated their efficiency as mass‐transfer promoters in a biphasic hydroformylation reaction catalysed by a rhodium trisulfonated triphenylphosphine system. These cationic α‐cyclodextrins greatly increased the reaction rate, the chemoselectivity, and, surprisingly, the linear‐to‐branched aldehyde ratio. We attributed this unexpected enhancement of the linear‐to‐branched aldehyde ratio to the in situ formation of new catalytic supramolecular species obtained by ion‐exchange between the catalyst ligand and the cationic α‐cyclodextrins.
Total Synthesis of Halipeptins: Isolation of Halipeptin D and Synthesis of Oxazoline Halipeptin Analogues
Authors: Nicolaou K. C. , Schlawe Daniel , Kim David W. , Longbottom Deborah A. , de Noronha Rita G. , Lizos Dimitrios E. , Manam Rama Rao , Faulkner D. John
Published: August 2005

The isolation from the marine sponge Leiosella cf. arenifibrosa and structural elucidation of halipeptin D (5), a relative of the previously isolated halipeptins A–C (1–3), is described along with the total synthesis of a number of oxazoline analogues (7 a–d and epi‐7 c–d). The developed synthetic strategy provides a flexible entry into the various isomers of the polyketide domain of the halipeptins and improvises for a late stage construction of the oxazoline ring after a macrolactamization process which secures the required macrocycle.
Nickel‐Iron Alloys with Special Soft Magnetic Properties for Specific Applications
Authors: Gehrmann Bodo
Published: August 2005

For Abstract see ChemInform Abstract in Full Text.
Non‐Covalent Aggregation of Discrete Metallo‐Supramolecular Helicates into Higher Assemblies by Aromatic Pathways: Structural and Chemical Studies of New Aniline‐Based Neutral Metal(II) Dihelicates
Authors: Vázquez Miguel , Bermejo Manuel R. , Licchelli Maurizio , González‐Noya Ana M. , Pedrido Rosa M. , Sangregorio Claudio , Sorace Lorenzo , García‐Deibe Ana M. , Sanmartín J.
Published: August 2005

Neutral manganese(II), iron(II), cobalt(II), nickel(II), zinc(II) and cadmium(II) complexes with an N‐tosyl‐substituted N4‐donor Schiff base containing a 4,4'‐methylenedianiline residue as spacer [H2La: N,N'‐bis(2‐tosylaminobenzylidene)‐4,4'‐methylenedianiline], and the zinc(II) complex with an analogous ligand [H2Lb: N,N'‐bis(2‐tosylaminobenzylidene)‐4,4'‐oxodianiline] have been prepared by an electrochemical procedure. FAB and ESI mass spectra of the complexes show peaks due to species corresponding to a general formula [M2(La,b)2 + H]+, thereby suggesting their dinuclear nature. A detailed study of the crystal packing in the unit cell of the zinc(II) complex with H2La shows that the helicates aggregate to form discrete prismatic moieties containing three molecules held together by π–π and σ–π interactions. Moreover, the ZnII neutral dihelicate with H2Lb forms a 3D network in the solid state due to intermolecular π‐stacking interactions. 1H NMR studies of the diamagnetic compounds reported herein have been performed. Finally, the ligand H2La and its ZnII and CdII complexes have been studied by spectrophotometric and spectrofluorimetric techniques in order to get a better understanding of the formation mechanisms of the complexes and of the nature of their fluorescence emission. Emission studies show that the ZnII and CdII dihelicates with H2La display a green fluorescence in acetonitrile solution (λ = 473 nm, Φ = 0.03 and λ = 476 nm, Φ = 0.01, respectively). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Synthesis, Structural Characterization, and Density Functional Study of Homo‐ and Heteropolyhalide Complexes of CuII with Dien and Dpta Ligands: Crystal Structure of [Bis(3‐aminopropyl)amine](bromo)(diiodobromo)copper(II)
Authors: Chaviara Aikaterini T. , Tsipis Athanasios C. , Cox Philip J. , Bolos Christos A.
Published: August 2005

Polyhalide mononuclear [CuX(L)(XY2)] and dinuclear [{CuX(L)}2(μ‐XY2X)] CuII complexes [L = diethylenetriamine (dien) or dipropylenetriamine (dpta); X = Cl, Br and Y = Br, I] have been obtained by treating the precursor [CuX2(L)] complexes with Br2 or I2 in 1:1 and 2:1 molar ratios. The new homo‐ and heteropolyhalide CuII complexes, either mononuclear or dinuclear, were predicted to be five‐coordinate CuII complexes exhibiting a distorted square‐pyramidal configuration. DFT calculations at the B3LYP level of theory provided a satisfactory description of the structures of all complexes, while the distorted square‐pyramidal structure of a representative complex, namely [CuBr(dpta)(BrI2)], was further substantiated by a single‐crystal X‐ray diffraction study. In the square‐pyramidal structure of [CuBr(dpta)(BrI2)], the basal plane of the pyramid involves three Cu–N contacts [1.990(7), 2.065(7), and 1.989(7) Å] from dpta and the Br(1) atom, while Br(2), which participates in the formation of the terminal [BrI2]– ligand, occupies the apical position. The Cu–Br(1) and Cu–Br(2) bond lengths were found to be 2.5797(14) Å (terminal) and 2.735(14) Å (bridging), respectively, while the Br1–Cu–Br2 bond angle is 98.83(5)°. The terminal [BrI2]– ligand is almost linear [Br–I–I bond angle of 174.48(3)°]. DFT calculations, spectroscopic measurements, including far‐IR and EPR studies, and magnetic measurements of the dinuclear complexes predict that the bridging tetrahalide XY2X moiety adopts a linear configuration as well. The bonding, electronic, and related properties of the complexes are also discussed in the framework of density functional theory. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Novel Structure Evolution of Lanthanide–SIP Coordination Polymers (NaH2SIP = 5‐Sulfoisophthalic Acid Monosodium Salt) from a 1D Chain to a 3D Network as a Consequence of the Lanthanide Contraction Effect
Authors: Liu Qing‐Yan , Xu Li
Published: August 2005

The new series of lanthanide–SIP coordination polymers [{Ln(SIP)(H2O)5}(H2O)3]n (Ln = Lu (1), Yb (2), Tm (3), and Er (4)], [{Ln(SIP)(H2O)4}]n (Ln = Ho (5), Dy (6), Tb (7), Sm (8), Pr (9), and Nd (10)], and [{La(SIP)(H2O)3}(H2O)]n (11), have been synthesized by hydrothermal reactions of Ln2O3 and 5‐sulfoisophthalic acid monosodium salt (NaH2SIP) at 160 °C and characterized by single‐crystal X‐ray diffraction. The unprecedented three structure types ongoing from LuIII to LaIII have been established: type I for the small ions, Lu, Yb, Tm, and Er; type II for the medium ions including Ho, Dy, Tb, Sm, Pr, and Nd; and type III for the largest La ion. Type I adopts a one‐dimensional zigzag chain‐like structure, type II exhibits a two‐dimensional undulate layer structure, and type III features a two‐dimensional double‐layer pillared by sulfonate groups to form a three‐dimensional open framework. The progressive structural changes from type I to type II and to type III with increasing atomic number were rationalized by the effect of the lanthanide contraction. Their spectroscopic properties and thermal stability were also investigated. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
An Unusual 3D Interdigitated Architecture Self‐Assembled from Sidearm‐Containing 2D Bilayer Motifs with a Cuboidal Framework
Authors: Wang Xin‐Long , Qin Chao , Wang En‐Bo , Xu Lin
Published: August 2005

The new complex [Zn(H2bptc)(bpy)]·0.5bpdo (1) [H4bptc = 3,3',4,4'‐biphenyltetracarboxylic acid, bpy = 4,4'‐bipyridine, and bpdo = 4,4'‐bipyridine N,N'‐dioxide] has been synthesized and characterized. It exhibits a novel (2D→3D) interdigitated architecture that is obtained for the first time from the self‐assembly of sidearm‐containing bilayer motifs with a cuboidal framework, in which each cuboidal box of one bilayer is interdigitated by two arms that belong to two adjacent bilayers. The luminescent properties of 1 are discussed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Impact of wildfires on surface water repellency in soils of northwest Spain
Authors: Varela M. E. , Benito E. , de Blas E.
Published: August 2005

Soil water repellency (hydrophobicity) is a naturally occurring phenomenon that can be intensified by soil heating during fires. Fire‐induced water repellency, together with the loss of plant cover, is reportedly the principal source of increased surface runoff and accelerated erosion in burned soils.

In this study, the surface water repellency of several soils affected by summer forest fires in northwest Spain was studied and compared with that of adjacent unburned soils. Soil water repellency was determined using the ethanol percentage test (MED).

Most of the unburned soil samples exhibited water repellency that ranged from strong to very strong; only four of the unburned soil samples were non‐repellent. Water repellency in the unburned soils was significantly correlated with the organic carbon content (r = 0·64, p < 0·05). Overall, fires increased the surface water repellency in soils with previously low degrees of water repellency and caused little change in that of originally strongly hydrophobic soils.

In order to examine in detail the changes in water repellency with temperature, three unburned soil samples were subjected to a controlled heating program. Water repellency increased between 25 and 220 °C, water repellency peaked between 220 and 240 °C and disappeared above 260–280 °C. Extrapolation of the results of the heating tests to field conditions suggested that the intensity of fire (temperature and time of residence) reached by most soils during fires is not too high. Based on the results, the determination of water repellency could be used as a simple test for the indirect estimation of the intensity levels reached on the soil surface during a fire. Copyright © 2005 John Wiley & Sons, Ltd.
Detection of ENSO‐influence on the monthly precipitation in South Korea
Authors: Jin Y.‐H. , Kawamura A. , Jinno K. , Berndtsson R.
Published: August 2005

During the latest several decades, there has been considerable interest in revealing the relationship between El Niño–southern oscillation (ENSO) and hydro‐meteorological variables. The oscillation is characterized by a simple index, the southern oscillation index (SOI). However, thus far, there is little evidence for the influence of ENSO in Korea and Japan. The influence of ENSO has also been studied in South Korea, but the estimated results are still qualitative and show an indirect relationship between ENSO and hydro‐meteorological variables. In this study we use simple approaches to reveal the quantitative and direct correlation between SOI and the monthly precipitation at five stations distributed over South Korea. The monthly precipitation data are transformed into nonexceedance probability time series because the data cannot be normally distributed by applying the usual transformations. The SOI is classified into five categories according to their values. Additionally, to detect the nonlinear relationship between categorized SOI and nonexceedance probability of the monthly precipitation, we use Kendall's τ, a nonparametric test. Significant correlations between the categorized SOI and the transformed precipitation are detected. Generally, the monthly precipitation is influenced by a La Niña event with a lag time of 4 months for southern coastal areas and a lag time of 5 months for middle to high regions in South Korea. Copyright © 2005 John Wiley & Sons, Ltd.
Hydraulic characteristics of a small Coastal Plain stream of the southeastern United States: effects of hydrology and season
Authors: Jin Hwa‐Seong , Ward G. Milton
Published: August 2005

Various physical and biological properties affect solute transport patterns in streams. We measured hydraulic characteristics of Payne Creek, a low‐gradient upper Coastal Plain stream, using tracer experiments and parameter estimation with OTIS‐P (one‐dimensional transport with inflow and storage with parameter optimization). The primary objective of this study was to estimate the effects of varying discharge, season, and litter accumulation on hydraulic parameters. Channel area A ranged from 0·081 to 0·371 m2 and transient storage area As ranged from 0·027 to 0·111 m2. Dispersion D ranged from 1·5 to 11·1 m2 min−1 and exchange coefficient α ranged from 0·009 to 0·038 min−1. Channel area and dispersion were positively correlated to discharge Q, whereas storage area and exchange coefficient were not. Relative storage size As/A ranged from 0·17 to 0·59, and was higher during fall than other seasons under a similar Q. The fraction of median travel time due to transient storage $F_{\rm med}^{200}$ ranged from 8·8 to 34·5% and was significantly correlated with Q through a negative power function. Both metrics indicated that transient storage was a significant component affecting solute transport in Payne Creek, especially during the fall. Comparison between the measured channel area Ac and A suggested that surface storage was dominant in Payne Creek. During fall, accumulation of leaf litter resulted in larger A and As and lower velocity and D than during other seasons with similar discharge. Seasonal changes in discharge and organic matter accumulation, and dynamic channel morphology affected the magnitude of transient storage and overall hydraulic characteristics of Payne Creek. Copyright © 2005 John Wiley & Sons, Ltd.
The influence of the mobile phase pH and the stationary phase type on the selectivity tuning in high performance liquid chromatography nucleosides separation
Authors: Kowalska Sylwia , Krupczyńska Katarzyna , Buszewski Bogusław
Published: August 2005

Analysis of the modified nucleosides is particularly important in the medical area because of a possibility of cancerogenic processes studies. The aim of this work was to study the selectivity tuning of modified nucleosides through the investigations of interactions analyte (modified nucleoside) ⇔ stationary phase ⇔ mobile phase. A series of homemade stationary phases with different surface properties has been utilized. All of them contain various interaction sites such as: cholesterol (SG‐CHOL); n‐acylamide (SG‐CHOL, SG‐AP); aminopropyl (SG‐CHOL, SG‐AP, SG‐NH2, SG‐MIX); cyanopropyl, phenyl, octyl (SG‐MIX), octadecyl (SG‐MIX, SG‐C18) and silanols localized on the silica gel surface of all packings. The attempt to predict the main interactions responsible for the retention between nucleosides and stationary phase ligands was done on the basis of the elemental analysis, and proportional part of an individual ligand bonded to silica surface results. In order to study the influence of different packing types on the analyzed nucleosides retention, the relationship between pH of the mobile phase buffer and the selectivity of a stationary phase was investigated.
Pharmaceutical analysis beyond compendial requirements
Authors: Sautel Magali , Krstulović Ante M.
Published: August 2005

Recent ICH recommendations on test procedures and acceptance criteria for new drug substances of synthetic chemical origin and new drug products produced from them (Q6A) sets the frame for registration of new chemical entities. These requirements are automatically applied by all pharmaceutical companies to products in late developmental phases. Furthermore, and justifiably so, they do not provide any guideline for setting specifications other than those for residual solvents and residues of heavy metal catalysts. During development of new chemical entities, ICH requirements represent a minimum beyond which additional testing has to be carried out in order to accumulate a body of scientific data which may ultimately permit simplified testing. This information is furthermore needed for drafting of registration files. This presentation will provide information on salt and polymorph selection, as well as morphology of particles. The need for more sophisticated techniques for assay of trace impurities by LC/MS will be illustrated with examples of alkylating agents. Complementary information from techniques such as CE, orthogonal to HPLC, is often needed to ensure absence of additional impurities. Finally, beyond compendial characterisation of hydroxypropylmethylcellulose, a commonly used excipient, by size exclusion chromatography with triple detection will be described.
Comparison of perfusion MRI by flow‐sensitive alternating inversion recovery and dynamic susceptibility contrast in rats with permanent middle cerebral artery occlusion
Authors: Hofmeijer J. , Schepers J. , van der Worp H. B. , Kappelle L. J. , Nicolay K.
Published: August 2005

We compared cerebral blood flow (CBF) parameters obtained by dynamic susceptibility contrast magnetic resonance imaging (DSC‐MRI) with those obtained by flow‐sensitive alternating inversion recovery (FAIR) in brain regions with different perfusion levels in rats with permanent middle cerebral artery (MCA) occlusion. MCA occlusion was performed in 19 rats. T2‐weighted MRI, FAIR and DSC‐MRI were performed within 48 h after occlusion. CBF parameters were analyzed in regions of interest with either prolonged or less prolonged mean transit time (MTT). Ratios of ipsi‐ vs contralateral CBF values were calculated and tested for correlation and differences between FAIR and DSC‐MRI. FAIR–aCBF ratios correlated significantly with DSC–rCBF ratios. The mean FAIR–aCBF ratio was significantly lower than mean DSC–rCBF ratio in the area with prolonged MTT. In the area with less prolonged MTT, the mean FAIR–aCBF ratio and mean DSC–rCBF values did not differ significantly. We conclude that FAIR correlates with DSC‐MRI if perfusion is preserved. FAIR provides lower CBF values than DSC‐MRI if perfusion is reduced and MTT is prolonged. This probable underestimation of perfusion may be caused by transit delays. Care should be taken when quantifying CBF with FAIR and when comparing the results of FAIR– and DSC‐MRI in areas with hypoperfusion. Copyright © 2005 John Wiley & Sons, Ltd.