bluuebunny/crossref_metadata_2025 huggingface dataset:
Interaction of serum albumin with vinyl sulfonate azo dye
Authors: Sereikaite Jolanta , Bumelis Vladas-Algirdas
Published: October 2008

The interaction between bovine serum albumin and the mono azo reactive dye Orange ZT has been investigated using absorption difference spectroscopy. The influence of pH and ionic strength of the solution on the stability of the dye-protein complex has been determined. At 25°C, the complex dissociation constants were equal to 24.0, 28.0, 7.0, 11.0, 17.6 and 46.0 μM at pH 7.0, 6.5, 6.0, 5.5, 5.0 and 4.3, respectively. In the presence of 0.1, 0.2, 0.3 M KCl, at pH 6.0 and 25°C, the complex dissociation constants were 8.8, 20.0, 18.0 μM, respectively. The protein-dye complex dissociation constants show that Orange ZT could be used as an affinity ligand for protein purification.
Intermolecular interactions in 2,4-dinitrophenylhydrazine hydrochloride hydrate: X-ray structural and quantum mechanical study
Authors: Kruszynski Rafal
Published: October 2008

2,4-dinitrophenylhydrazine hydrochloride hydrate (I) was determined by X-ray crystallography, and the intermolecular interaction energies were calculated in terms of Natural Bond Orbital analysis. The asymmetric unit of (I) consists of a dinitrophenylhydrazinium cation, a chloride anion and a water molecule. The interatomic distances and angles in (I) show no unusual values. In the structure there are intermolecular N—H⊎⊎⊎O, N—H⊎⊎⊎Cl, O—H⊎⊎⊎Cl, C—H⊎⊎⊎O hydrogen bonds with bonding energy ranging form 16.03 to 0.76 kcal mol−1. These hydrogen bonds create the following N1 motifs: 6D, S(5), S(6), C(6), C(9). N1D motifs become infinite at the third level and are 2C 32(6), C 32(7).
Spectral properties of tetraanionic porphyrin in formamide colloids of layered double hydroxides
Authors: Bujdák Juraj , Iyi Nobuo
Published: October 2008

Formamide colloidal suspensions of layered double hydroxides (LDHs) with anionic dye, meso-tetrakis(4-sulfonatophenyl)porphine (TPPS) were prepared. Optical properties of these suspensions were investigated by means of absorption and fluorescence spectroscopies in the visible region. For more detailed characterization, second derivative curves of the spectra were calculated. The adsorption of the dye on LDH nanosheets led to partial molecular aggregation, reflected in significant changes of the dye optical properties. The Soret band in the absorption spectra was split into two peaks and decreased in intensity. Changes were observed also for the Q-bands. The molecular aggregation significantly quenched the emission of the dye. The low intensity emission from dye H-aggregates was identified at slightly longer wavelengths. The molecular aggregation increased with the dye/LDH ratio. At low dye loadings, the optical properties were very similar to the dye solution. The yields of the dye molecular aggregation increased with LDH surface charge.
Properties of naproxen ion-selective electrodes
Authors: Lenik Joanna , Wardak Cecylia , Marczewska Barbara
Published: October 2008

Naproxen membrane electrodes based on different plasticizers and the quaternary ammonium salts (QASs) dimethyldidecylammonium bromide, methyltrioctylammonium chloride, or tetraoctylammonium chloride, were prepared. The following basic parameters were investigated for the optimal electrode: measurement range (10−4 − 10−1 mol L−1), slope of the linear range of the calibration curve (−58.3 mV decade−1), limit of detection (6.0 × 10−5 mol L−1), lifetime (2.5 months), dependence of the electrode potential on pH (5.5 − 9.0), reproducibility of potential (1.2 mV) and selectivity coefficients in relation to selected organic and inorganic anions. The electrode was utilized for determination of naproxen in tablets by the calibration curve method and the standard addition method.
A first-principles study of Ï€-conjugated thiol phenothiazine derivatives adsorbed on Au(111) surface
Authors: Morari Cristian , Bogdan Diana , Turcu Ioan
Published: October 2008

We present an extensive theoretical study of a series of phenothiazine derivatives adsorbed on Au(111). A series of experimentally accessible quantities are calculated (ultra-violet photoemission spectra, scanning tunneling microscopy images). All simulations were performed by using DFT techniques and LCAO expansion of the molecular orbitals. The microscopic picture established in this work provides a deeper understanding of the interfacial processes that govern the working principle of single-molecule electronics and organic electronic devices.
Psychosomatic correlates of coronary heart disease during the socio-economic crisis of post-communist Bulgaria
Authors: Karaslavova Emilia , Dyakova Mariana , Todorova Desislava , Tufkova Stoilka
Published: October 2008

Post-communist Bulgaria has experienced the full impact of a socioeconomic disaster. Under prolonged and powerful stress the human body may exhaust its adaptive potential and a variety of pathophysiological symptoms may occur. The cardiovascular system is most vulnerable to stress. The aim of this study is to analyze the role of psychological factors correlating with Acute Myocardial Infarction (AMI) during the transition period in post-communist Bulgaria. A case-control epidemiological study was performed. 306 cases of acute myocardial infarction (AMI) and 210 controls were studied. Analysis of patients’ records was made and a direct face-to-face interview was carried out. The study covers a 15-year transition period lasting from 1989 until 2005. The interview questions are based on W. Zung’s standardized self-evaluation tests of anxiety and depression (Self Rating Depression Scale — SDS, 1965, SAS-Self Rating Anxiety Scale, 1976) and on a test of aggression, as a part of the Minnesota Multiphase personality inventory, adapted from A.A. Krilov and F. Korozi’s FPI test. Average levels of anxiety and depression appear to be higher among patients suffering from coronary heart diseases than in control group members. Levels of aggression do not show a direct correlation with coronary heart disease. Both groups demonstrate symptoms of psychological disturbances caused, most probably, by the socio-economic instability of the transition period. In conclusion, certain socioeconomic factors significantly increase the level of anxiety and depression in the respondents. The AMI patients are considerably more anxious and depressed than the controls. The results provide evidence that high levels of anxiety and depression may correlate to and be interpreted as a potential risk factor for coronary heart disease.
Effect of Dietary Supplementation with Vitamin E and Selenium in Thoroughbred Horses on the Concentration of F2-isoprostanes in the Blood Plasma as a Marker of Lipid Peroxidation
Authors: Härtlová H. , Rajmon R. , Dörflerová A. , Zita L. , Řehák D. , Rosmus J. , Šindelář M. , Klabanová P.
Published: October 2008

The objective of this study was to assess the effect of vitamin E and selenium (Se) supplementation on the plasma levels of F2-isoprostanes as a marker of oxidative stress in horses in their training period. Twelve healthy 3-year-old English thoroughbred horses were divided into two groups: control (n = 6) and experimental (n = 6). Feeding rations were adapted to a moderate workload. The horses of the experimental group received supplements of DL-α-tocopheryl acetate E (2 250 mg/day/horse) and of sodium selenite (0.5 mg/day/horse). The plasma concentrations of both antioxidants and F2-isoprostanes were monitored on days 0, 44 and 70. After 70 days of supplementation, the concentrations of selenium in the experimental group were significantly higher (P < 0.05) compared to the beginning of the experiment (mean ± SE: 135.81 ± 10.19 μg l -1 vs. 98.70 ± 10.88 μg l -1), as well as to the control group (day 0: 101.78 ± 11.06 μg l -1, day 70: 108.18 ± 7.77 μg l -1). In the horses of the experimental group, plasma α-tocopherol levels significantly increased from the 44th day of supplementation compared to the beginning of the study as well to the control group (5.23 ± 0.52 mg l -1 vs. 2.45 ± 0.25 mg l -1 or 3.46 ± 0.34 mg l -1, respectively). The plasma concentration of F2-isoprostanes tended to be lower in the experimental group at the end than at the beginning of monitoring (156.8 ± 12.89 pg l -1 vs. 170.3 ± 60.8 pg l -1), although the control group showed the opposite trend (181.2 ± 15.67 pg l -1 vs. 137.0 ± 47.05 pg l -1). Nevertheless, none of these differences were significant because of the large variability of the individual values. It can be stated that supplementation of the diet used with selenium and vitamin E caused a non-significant decrease of F2-isoprostane concentration in the blood plasma only, and a significant increase of plasma concentrations of these antioxidants. The variation of isoprostane levels probably reflected rather the individual responses of the horses' organisms to the training workload.
Content of Glutathione and Vitamin C in the Liver of Rats Exposed to Dimethoate and Pyrantel Tartrate
Authors: Spodniewska A. , Zasadowski A.
Published: October 2008

The study was undertaken to examine the effect of oral administration of dimethoate (Bi 58 Nowy) and/or pyrantel tartrate on the concentration of glutathione (GSH) and vitamin C in rat liver. Rats of Group I were administered pyrantel tartrate at a dose of 85 mg/kg b.w. at a twoweek interval, while the animals of Group II received Bi 58 Nowy (38% dimethoate) at a dose of 25 mg/kg b.w. for 28 days, and animals of Group III received both compounds together as described above. Pyrantel tartrate was found to increase the concentration of glutathione in the liver, whereas the content of vitamin C oscillated around values reported for the control. After a 28-day exposure to dimethoate (Bi 58 Nowy), except for the 6th hour after intoxication, the content of GSH was observed to increase and significant differences (p ≤ 0.05) occurred after days 3 and 14 (p ≤ 0.01). The concentration of vitamin C in liver homogenates after dimethoate administration was decreased compared to the control until day 3. An increase was then observed continuing until the end of the experiment. In animals receiving both compounds, except for day 7, the concentration of vitamin C was slightly decreased. The administration of pyrantel tartrate before dimethoate (Bi 58 Nowy) only in some time intervals was found to reduce the intensity of changes evoked by the exclusive administration of insecticide. It may suggest that not in all cases of mixed intoxications, intensification should be expected in changes of the variables analyzed.
Oral Papillomatosis in a Dog and its Therapy with Taurolidine
Authors: Biricik H. S. , Cabalar M. , Gulbahar M. Y.
Published: October 2008

The efficacy of taurolidine on the treatment of oral papillomatosis in a 1-year-old Turkish Kangal dog was evaluated. Diagnosis of the papillomatosis was based on clinical signs, histopathological and immunohistochemical examinations. The dog received 45 mg/kg taurolidine intravenously every 3 days. Regression of papillomas started to be observed after the beginning of treatment, and complete resolution occurred after the fifth application.
Impact of Supplementation of Various Selenium Forms in Goats on Quality and Composition of Milk, Cheese and Yoghurt
Authors: Pechová A. , Janštová B. , Mišurová L. , Dračková M. , Vorlová L. , Pavlata L.
Published: October 2008

The objective of this experiment was to monitor the possibility of influencing the composition of milk and milk products by supplementing the feed of lactating goats with selenium in various forms (natrium selenite, selenium proteinate). The trial was carried out in 30 goats, divided into 3 groups: Group C (n = 10) was a control group, SeI group (n = 10) received selenium in the form of natrium selenite and SeO group (n = 10) in the form of lactate-protein complex produced by Lactobacillus acidophilus. Diverse selenium supplementations were carried out from 3.5–4 months before the date of delivery until the 2nd month of lactation. In the time span of 2 weeks, milk from individual goats was taken six times and cheeses and yoghurts were made from the mixed milk from individual groups. During the period of milking and making milk products, the goats in experimental groups received added 565 μg Se per animal and day in relevant forms. Long-term selenium supplementation in the form of natrium selenite/proteinate had no significant effect on the Se concentration in milk. Se concentration in milk of individual groups was as follows: C: 13.14 ± 4.21 μg l-1, SeI: 12.50 ± 5.59 μg l-1, SeO: 12.47 ± 3.71 μg l-1. Similarly, no significant differences in the selenium concentration were determined in yoghurts (C: 17.13 ± 5.40 μg kg-1, SeI: 18.12 ± 5.49 μg kg-1, SeO: 19.69 ± 6.48 μg kg-1) and cheeses (C: 68.79 ± 7.14 μg kg-1, SeI: 70.41 ± 6.22 μg kg-1, SeO: 69.66 ± 12.68 μg kg-1) made from milk of individual goats groups. Apart from selenium concentration in milk and milk products, we also monitored other quality indicators that might have been influenced by selenium supplementation in the goats' feed. Among qualitative milk indicators, we found significantly lower titration acidity and significantly higher rennetability in SeI group. We also determined a significantly higher fat concentration in milk of SeO group compared to the other two groups. Indicators monitored during production of yoghurts and cheeses were not influenced significantly, only fat concentration in yoghurts was higher in SeO group compared to SeI group. Supplementation of selenium in the form of natrium selenite and selenium proteinate exceeding the physiological needs of goats had no significant effect on the Se concentration in milk and milk products.
Salinomycin Concentration in Eggs and Tissues of Laying Hens
Authors: Šinigoj-Gačnik K. , Rojs O. Zorman
Published: October 2008

The objective of our study was to monitor the presence of salinomycin in eggs and tissues of laying hens fed with rations containing 60 mg kg-1 salinomycin sodium for five days. Residues of salinomycin were determined on the day of withdrawal from salinomycin treatment in the breast and thigh muscle, liver, abdominal fat and ovarian yolk. In eggs, residues of salinomycin were monitored in both yolk and albumen daily from the beginning of treatment until the tenth day after withdrawal. Salinomycin was first found in yolk 1 day after starting the treatment and persisted for 8 days after withdrawal. The highest average level, 480 μg kg-1, was present on the third day after withdrawal. In albumen, levels of salinomycin residues were significantly lower, with a maximum level of 15 μg kg-1 reached on the fifth day of the experiment; and they were only found up to one day after withdrawal. Salinomycin was found in all ovarian yolks present in the body of layer hens in a concentration range between 237 and 553 μg kg-1. It was also found in the abdominal fat (concentration range from 62 to 237 μg kg-1) and the liver (concentration ≤ 10 μg kg-1), but not in breast or thigh muscle tissues. No changes in salinomycin residues were observed after cooking and frying the eggs.
Financial Compensations for Losses Due to Bovine Spongiform Encephalopathy in the Czech Republic in 2001-2007
Authors: Pospíšil R. , Pospíšil Z. , Zendulková D. , Lány P.
Published: October 2008

Based on Czech legislature, the farmers whose herds were affected by bovine spongiform encephalopathy (BSE) are reimbursed for the costs associated with disease diagnosis, killing the animals and safely disposing of their carcasses, decontamination of their premises, if necessary, and compensations for the value of the animals killed and for losses due to non-materialised production. Between 2001 and 2007, a total of 1,194,743 were examined for BSE, 27 BSEpositive cases were detected and, consequently, 3,997 animals were killed and destroyed. To reduce the negative economic impact on agricultural production, farmers were compensated for selected cost items by the Ministry of Finance of the Czech Republic from the state budget. The costs of examination for BSE, killing of animals and destroying their carcasses, and decontamination of farms were CZK 18.9 million (9.7%), compensations for the value of the animals killed amounted to almost CZK 164.0 million (83.3%) and compensations for nonmaterialised production reached almost CZK 13.6 million (6.9%). Together with some additional costs, the total of reimbursements during the period of 2001–2007 in the Czech Republic was almost CZK 197 million. These results are discussed in comparison to rather scarce data in the international literature which reports only the total costs associated with BSE occurrence and not individual cost items by which cattle and beef producers are burdened.
"Back to the Future": A Comparative Ethical Look at Israeli Arab Future Vision Documents
Authors: Abulof Uriel
Published: October 2008

Israeli Arabs' "future vision" documents are an ethical-political manifesto, contextualized in academic discourse and informed by socio-historical parallels. Hence, this article examines their political ethics in a comparative perspective, by referencing the case of Israeli Arabs along with two other distinct intra-state conflicts: the strife between Anglophones and Francophones in Canada and the struggle between Macedonians and Albanians in Macedonia. These cases illuminate two main ethical-political alternatives to the present pattern of relations between Jews and Arabs in Israel. Although the Canadian case indicates a renunciation of ethno-nationalism in favor of civic and linguistic patriotism, the Macedonian case presents an attempt to reconcile ethno-national affiliation with democratic principles. Projecting the ethical discussion of the Canadian and Macedonian cases onto Israel, I contend that normative acceptance of the mutual and dual right of self-determination, regarding both the individual's collective identity and the collective's polity, is a precondition for reconciliation between Jews and Arabs.
The Economics of Pastoralism: Study on Current Practices in South America
Authors: Westreicher Carlos Andaluz , Mérega Juan Luis , Palmili Gabriel
Published: October 2008

Transhumance is the regular movement of herds between fixed points to exploit seasonal availability of pastures. This is precisely the system presently employed in the South American Andes, using a vertical movement, usually between established points and linked through routes that sometimes are very ancient and mostly related to the herding of camelids (llama, alpaca, vicuña and guanaco). Pastoralist activities in South America are present in four countries, Argentina, Bolivia, Chile and Peru. In Argentina and Chile pastoralism occupies marginal areas, and its economic relevance lies in its capacity to fill economic niches (goat herding in northern Chile and southern Argentina; camelid herding in northern Argentina). Bolivia and Peru are, for historical, cultural and geographical reasons, in the heart of South American pastoralism and the importance of pastoralist activities is especially significant to both of these countries' economies.
A Quantum Theory of Thermodynamic Relaxation
Authors: Tsekov Roumen
Published: October 2008

A new approach to quantum Markov processes is developed and the corresponding Fokker-Planck-like equation is derived. The latter was examined to reproduce known results from classical and quantum physics. It was also applied to the phase-space description of a mechanical system thus leading to a new treatment of this problem different from the Wigner presentation. The equilibrium probability density obtained in the mixed coordinate-momentum space is a reasonable extension of the Gibbs canonical distribution.
Glycerol-Induced Aggregation of the Oligomeric L-Asparaginase II from E. coli Monitored with ATR-FTIR
Authors: Adeishvili Koba
Published: October 2008

In this paper attenuated total reflectance Fourier transform infrared spectroscopy has been employed for the study of the structural composition of aggregates of the oligomeric L-asparaginase II from E.coli formed in the presence of glycerol after the induction of refolding of the protein. Apart from the perfect coincidence of the secondary structure composition of EcA2 as determined by FTIR and crystallography [1], it has also been shown that secondary structure of protein in asparaginase deposits is similar to that of the native conformation: 20.7% extended, 22.3% disordered, 31.4% helix and 25.6% turn/bend/β sheet. Certain structural similarities in the range of experimental error was observed for all three protein deposits presented in this paper, indicating a common structural basis for the composition of this types of aggregates. It is concluded that in the constitution of such precipitates, a partially folded (molten globule like) state(s) is involved, and its stabilisation is a key factor leading to the aggregation. The results presented in this paper might serve to be a good explanation and an excellent basis for the fundamental theory of protein (oligomers) precipitation by osmotic substances.
The H2/O2 Reaction on a Palladium Model Catalyst Studied with Laser-Induced Fluorescence and Microcalorimetry
Authors: Johansson Åsa , Försth Michael , Rosén Arne
Published: October 2008

The H2/O2 reaction on a polycrystalline palladium foil has been studied. The experimental methods used were Laser-Induced Fluorescence (LIF) and microcalorimetry. The reaction was also simulated with the Chemkin software package. The water production maximum occurs at 40% H2 and the OH desorption has its maximum at 10% H2, at a total pressure of 100 mTorr (13 Pa) and a catalyst temperature of 1300 K. It is concluded, in agreement with the simulations, that the main water-forming reaction at these experimental conditions is OH+H→H2O. From the water production maximum the quotient of the initial sticking coefficient for hydrogen and oxygen (SH2(0)/SO2(0)) is calculated to be 0.75(±0.1).
Four-Reference State-Specific Brillouin-Wigner Coupled-Cluster Method: Study of the IBr Molecule
Authors: Pittner Jiří , Demel Ondřej , Čársky Petr , Hubač Ivan
Published: October 2008

We implemented the state-specific Brillouin–Wigner coupled-cluster method for the complete model space spanned by four reference configurations generated by two electrons in two active orbitals. We applied the method (together with the previously suggested a posteriori size-extensivity correction) to the calculation of spectroscopic constants of the IBr molecule, using averaged relativistic effective core potential.
Conservation Equations for Chemical Elements in Fluids with Chemical Reactions
Authors: Piña E. , De la Selva S.M.T.
Published: October 2008

It is well known that when chemical reactions occur, the masses of the participating molecules are not conserved, whereas the masses of the nuclei of the chemical elements constituting these same molecules, are conserved. Within the context of non-equilibrium thermodynamics, the first fact is expressed by the differential balance equations, for the densities of the chemically reacting molecules, having a non zero source term. At the same time the conserved quantities like the total mass, charge and energy obey differential conservation equations, i.e with zero source term. In this paper, we show that in fluids with chemical reactions occurring in them, there are additional conserved quantities, namely densities associated to the fact that the masses of the chemical elements are conserved. The corresponding differential conservation equations are derived. The found out conserved densities, one for each involved chemical element are shown to be linear combinations of the densities of those reacting molecules containing the element, weighted with the number of atoms of the element in the species. It is shown that in order to find the conserved densities, it is not necessary to know explicitly the reactions taking place. Some examples are provided.
Charge Transfer in Ionic and Molecular Systems
Authors: Bacchus-Montabonel Marie-Christine
Published: October 2008

Charge transfer reactions are fundamental processes present in almost all areas of physics, chemistry and biochemistry.[...]
Alignment-Dependent Atomic Model for Electron Transfer in Ion-Molecule Collisions
Authors: Lin C. D. , Reiser Ingrid
Published: October 2008

The alignment-dependent atomic model for treating electron transfer processes in ion-molecule collisions [Shingal and Lin, Phys. Rev. 1989, A40, 1302] is reviewed. This model has been applied to collisions between H+ and He2+ with H2, and recently also to collisions between He2+ and Ar2+ ions with H2+, where alignment effect is being explored experimentally.
Single Electron Capture in Slow Collisions of Doubly Charged Ions with Dinuclear Molecules
Authors: Albu Mihaela , Mrazek Libor , Aumayr Friedrich , Winter Hannspeter
Published: October 2008

We have performed translational-spectroscopical measurements on single electron capture (SEC) by impact of slow (impact energy ≤ 1 keV) doubly charged ions on dinuclear molecules. For impact of C2+ and N2+ ions the influence of their metastable fractions on the SEC probability has been studied. For impact of 4He2+ on O2 and CO direct and dissociative SEC have been investigated. For all collision systems studied the principal SEC channels can be explained by the "reaction window" which results from multichannel-Landau-Zener treatments for the collisional quasimolecules.
Highlights in Solute-Solvent Interactions
Authors: Linert W.
Published: October 2008

This book [2] emphasizes a broad spectrum of features in solution chemistry, reaching from recent developments in the empirical characterization of solvent-solute interactions up to modern theoretical descriptions of liquid-state systems, from solid-liquid interfaces to preferential solvation in mixed solvents.[...]
Can Unrestricted Density-Functional Theory Describe Open Shell Singlet Biradicals?
Authors: Gräfenstein Jürgen , Kraka Elfi , Filatov Michael , Cremer Dieter
Published: October 2008

Unrestricted density functional theory (UDFT) can be used for the description of open-shell singlet (OSS) biradicals provided a number of precautions are considered. Biradicals that require a two-determinantal wave function (e.g. OSS state of carbenes) cannot be described by UDFT for principal reasons. However, if the overlap between the open-shell orbitals is small (the single electrons are located at different atomic centers) errors become small and, then, the principal failure of UDFT in these cases is not apparent and may even be disguised by the fact that UDFT has the advantage of describing spin polarization better than any restricted open shell DFT method. In the case of OSS biradicals with two- or multiconfigurational character (but a onedeterminantal form of the leading configuration), reasonable results can be obtained by broken-symmetry (BS)-UDFT, however in each case this has to be checked. In no case is it reasonable to lower the symmetry of a molecule to get a suitable UDFT description. Hybrid functionals such as B3LYP perform better than pure DFT functionals in BS-UDFT calculations because the former reduce the self-interaction error of DFT exchange functionals, which mimics unspecified static electron correlation effects, so that the inclusion of specific static electron correlation effects via the form of the wavefunction becomes more effective.
Zeolite-Catalyzed Hydrocarbon Formation from Methanol: Density Functional Simulations
Authors: Govind Niranjan , Andzelm Jan , Reindel Kurt , Fitzgerald George
Published: October 2008

We report detailed density functional theory (DFT) calculations of important mechanisms in the methanol to gasoline (MTG) process in a zeolite catalyst. Various reaction paths and energy barriers involving C-O bond cleavage and the first C-C bond formation are investigated in detail using all-electron periodic supercell calculations and recently developed geometry optimization and transition state search algorithms. We have further investigated the formation of ethanol and have identified a different mechanism than previously reported [1], a reaction where water does not play any visible role. Contrary to recent cluster calculations, we were not able to find a stable surface ylide structure. However, a stable ylide structure built into the zeolite framework was found to be possible, albeit a very high reaction barrier.
Special Issue on Recent Advances in Coupled Cluster Theory
Authors: Pal Sourav
Published: October 2008

The Coupled-cluster (CC) theory has emerged as the most accurate method to describe the electron correlation problem and thus the state-of-the-art electronic structure tool.[...]
Implicit and Explicit Coverage of Multi-reference Effects by Density Functional Theory
Authors: Cremer Dieter , Filatov Michael , Polo Victor , Kraka Elfi , Shaik Sason
Published: October 2008

Multi-reference effects can be covered by density functional theory (DFT) either implicitly via the exchange-correlation functional or explicitly via the form of the Kohn-Sham wave function. With the help of the exchange hole it is shown that the self-interaction error of the exchange functional will mimic long-range electron correlation effects if restricted Kohn-Sham theory is used. Functionals based on Slater or Becke exchange have a relatively large self-interaction error and, therefore, lead to a relatively large implicit coverage of long-range correlation, which, because of the possibility of doublecounting of electron correlation, has to be considered when using these functionals in connection with two- or multi-configurational descriptions based on ensemble DFT methods such as REKS (spin-Restricted Ensemble-referenced KS-DFT). Arguments are given that a REKS description of a multireference problem avoids a double-counting of long-range correlation effects, in particular as in this situation the self-interaction error of the exchange functional simulates more short- rather than longrange correlation effects. There is, however, no guarantee that the short-range effects are not doublecounted, namely once via the exchange and once via the correlation functional. Therefore, one should use hybrid functionals such as B3LYP in connection with multi-reference DFT methods because for hybrid functionals the self-interaction error and by this the implicit coverage of long(short)-range correlation effects is reduced due to the admixture of exact exchange. This rule applies also to broken-symmetry UDFT, which performs better with hybrid rather than GGA functionals. A way of avoiding the implicit coverage of multi-reference effects is given by the combination of wave function theory and DFT methods. The advantages and disadvantages of CAS-DFT are discussed and it is shown that an effective reduction of a double-counting of correlation effects is possible within this method.
Reverse Phase Thin Layer Chromatography of Aminoalkanethiosulfuric Acids, Mercaptoalkanamines and Aminoalkyl Disulfides
Authors: Das Graças Cardoso Maria , Nelson David Lee , Tavares do Amaral Antônia , Dos Santos Custódio Donizete , De Abreu Pereira Alcilene , De Oliveira Ana Cláudia Barneche
Published: October 2008

The experimental Rm values for a series of aminoalkanethiosulfuric acids, mercaptoalkanamines and aminoalkyl disulfides were determined by reverse phase thin layer chromatography. The Rm values were determined for various concentrations of methanol: water and the correlation obtained was extrapolated to 100% water. These values permitted the calculation of the log P values for each substance. The log P values obtained by this method were compared with those obtained using the shake-flask method and by theoretical calculations utilizing fragment constants.
Quantitative Structure–Property Relationships for Aryldiazonia
Authors: Pankratov Alexei  N. , Zhelezko Oxana  I.
Published: October 2008

By the fact of finding 43 relationships, we have shown that the reduction potentials, dimerization potentials and potentials in half-equivalent point on titration of aryldiazonium cations XC6H4N+≡N (chemical reduction with K4[Fe(CN)6] and TiCl3 in water, (C2H5)3N, (í-C4H9)4N+−OH, CH3OK and C10H8•−Na+ in acetone; polarographic reduction in nitromethane, sulfolane, and N,N-dimethylformamide) are related linearly to the quantum chemically evaluated electron affinities (A) and to the stabilization energies of radicals formed on diazonium cations reduction. Sixty six linear correlations of frequencies (ν) characterizing a collection of bonds stretching vibrations of the C-N+≡N fragment in the XC6H4N+≡NY− salts with different anions in vaseline oil, N,N-dimethylformamide, acetone, ethylacetate, methanol, water, with the bonds orders of N≡N and C-N, with the charges on carbon atoms in para positions of the C6H5X molecules aromatic rings, with the mesomeric dipole moments (μm) of X substituents have been found. Twelve quantitative relationships combining the μm and ν quantities with the A values have been established. The interrelations obtained have an explicitly expressed physical meaning, are featured by rather high correlation coefficients and have a predictive power in respect to redox properties, electron affinities, vibrational frequencies of aryldiazonia, as well as to mesomeric dipole moments of atomic groups in organic molecules.
Ab Initio Calculations of Co Shielding in Model Complexes
Authors: Moore Elaine A.
Published: October 2008

Recent ab initio calculations of cobalt NMR shielding show that DFT-GIAO calculations using hybrid functionals are found to reproduce experimental values well. This method is used to calculate the variation of the cobalt NMR shielding tensor of sqaure pyramidal nitrosyl complexes with respect to the CoNO geometry and to differing basal ligands. The isotropic shielding is shown to have a large negative derivative with respect to CoX distance where X is a ligating atom.; the derivative with respect to NO distance is smaller but still significant. The zz component where z is along the CoN(NO) bond is more sensitive to the basal ligands but the other two principal components are sensitive to the CoNO geometry.
Self-energy Effects on Nuclear Magnetic Resonance Parameters within Quantum Electrodynamics Perturbation Theory
Authors: Romero Rodolfo , Aucar Gustavo
Published: October 2008

A theory for the calculation of self-energy corrections to the nuclear magnetic parameters is given in this paper. It is based on the S-matrix formulation of bound-state quantum electrodynamics (QED). Explicit expressions for the various terms of the S-matrix are given. The interpretation of the self-energy, one- and two-vertex terms and some perspective for possible future developments are discussed.
Special Issue on Recent Advances in Environmental Health Research: Health Disparities, Toxicology and Carcinogenesis
Authors: Tchounwou Paul , Yu Hongtao
Published: October 2008

Recent development in biomedical research and clinical sciences has lead to a significant decrease in disease morbidity and mortality, as well as the improvement of quality of life in the United States and around the world.[...]
Effect of Turmerin on Endothelial Denudation by Air Drying
Authors: Cohly H. H. P. , Hammet C. , Angel M. F. , Kanji V. , Taylor A. , Benghuzzi H. , Markov A. K.
Published: October 2008

The objective of this study is to determine if arterial endothelial injury can be attenuated by local application of 80 μg/ml turmerin at the site of injury and by oral administration of the same dose. Anesthetized Lewis rats (n =12) weighing 200 ± 4.0 gms randomly were assigned to two groups. After 5 min of air drying a segment of right carotid artery, six rats were treated locally 80μg/ml with turmerin and the rest were treated with 0.9% NaCl. Turmerin was then administered by gavage (80 μg) every 24 hrs for 14 days. Animals were sacrificed on day 14 and the carotid artery removed from the injured site for histological analysis and serum collected for lipid peroxidation analysis by measuring malondialdehyde (MDA) and conjugated dienes. This study showed no proliferation in the intima of one rat out of six rats treated with turmerin while there was significant variation between the treated rats and the controls. MDA for control was 0.593±0.02 nanomoles/ml while turmerin was 0.187±0.04 (p≤0.01); conjugated diene for control was 0.402±0.03 nanomoles/ml while turmerin was 0.212±0.04 nanomoles/ml (p ≤0.05). Although there was significant reduction in serum peroxidation activity, the histological findings indicate that attenuation of carotid artery injury may involve other factors than decreased lipid peroxidation.
Health Risk Assessment of Pesticide Usage in Menia El-Kamh Province of Sharkia Governorate in Egypt
Authors: Tchounwou Paul B. , Ashour Bassem A. , Moreland-Young Curtina , Ragheb Didair A. , Romeh Ahmed A. , Goma El-Adarosy , El-Sheikh Sayed , Lidell Frances P. , Ibitayo Olurominiyi , Assad Jean-Claude
Published: October 2008

Menia El-Kamh province of the Sharkia Governorate constitutes one of the largest agricultural areas in Egypt. About 88% of the nearly 472,000 people living in this province rely on agricultural activities for subsistence. Several pesticides including organochloride, organophosphorus, carbamate, and pyrethroid insecticides, fungicides, and herbicides are commonly used in citrus, vegetable and other crop-growing areas to increase agricultural productivity. However, their use has also been associated with several cases of pesticide poisoning. In this research, we conducted a field survey to assess the knowledge, attitudes, and practices of the farmer’s community regarding the safe use of pesticides. We also evaluated the residual concentrations of selected pesticides in water, soil, milk, fish, and orange samples, and estimated the potential health risks associated with the exposure to these pesticides. Data obtained from the field survey indicate that more than 95% of farm workers do not practice safety precautions during pesticide formulation and application; leading to a considerable prevalence of pesticide-related illnesses in this agricultural community. Pesticide residues in various environmental samples varied greatly; from below detection levels (3-5 ng) to as high as 325 ppb depending on the matrix of interest, and the specific pesticide of concern. The analysis of health risk estimates indicated that chlorpyrifos, DDT, dimethoate, methomyl, and larvin did not pose a direct hazard to human health, although present in water, milk, orange, and/or fish. However, aldicarb, and carbosulfan levels exceeded the reference doses, indicating a great potential for systemic toxicity, especially in children who are considered to be the most vulnerable population subgroup. The upper-bound values of cancer risk from DDT exposure were estimated to be about 8 (adults), and 55 (children) excess cancers in a population of one million.
Solvent Effects on Nuclear Magnetic Resonance 2J(C,Hf) and 1J(C,Hf) Spin–Spin Coupling Constants in Acetaldehyde
Authors: Zaccari Daniel , Barone Verónica , Peralta Juan E. , Contreras Rubén H. , Taurian Oscar E. , Díez Ernesto , Esteban Angel
Published: October 2008

The known solvent dependence of 1J(Cc,Hf) and 2J(C1,Hf) couplings in acetaldehyde is studied from a theoretical viewpoint based on the density functional theory approach where the dielectric solvent effect is taken into account with the polarizable continuum model. The four terms of scalar couplings, Fermi contact, paramagnetic spin orbital, diamagnetic spin orbital and spin dipolar, are calculated but the solvent effect analysis is restricted to the first term since for both couplings it is by far the dominant contribution. Experimental trends of Δ1J(Cc,Hf) and Δ2J(C1,Hf) Vs ε (the solvent dielectric constant) are correctly reproduced although they are somewhat underestimated. Specific interactions between solute and solvent molecules are studied for dimethylsulfoxide, DMSO, solutions considering two different one-to-one molecular complexes between acetaldehyde and DMSO. They are determined by interactions of type C=O---H---C and S=O---H---C, and the effects of such interactions on 1J(Cc,Hf) and 2J(C1,Hf) couplings are analyzed. Even though only in a semiquantitative way, it is shown that the effect of such interactions on the solvent effects, of Δ1J(Cc,Hf) and Δ2J(C1,Hf), tend to improve the agreement between calculated and experimental values. These results seem to indicate that a continuum dielectric model has not enough flexibility for describing quantitatively solvent effects on spin-spin couplings. Apparently, even for relatively weak hydrogen bonding, the contribution from “direct” interactions is of the same order of magnitude as the “dielectric” effect.
The Spin–Spin Coupling Constants in Ethane, Methanol and Methylamine: A Comparison of DFT, MCSCF and CCSD Results
Authors: Pecul Magdalena , Helgaker Trygve
Published: October 2008

The spin–spin coupling constants in ethane, methylamine, and methanol have been calculated using density-functional theory (DFT), coupled-cluster singlesand-doubles (CCSD) theory, and multiconfigurational self-consistent field (MCSCF) theory so as to benchmark the performance of DFT against high-level ab initio methods and experimental data. For each molecule, the Karplus curve has been evaluated at the three computational levels. The comparisons with ab initio methods indicate that DFT reproduces the 1J(CH), 1J(CC), and 1J(NH) one-bond couplings well but is less accurate for 1J(CN), 1J(OH), and 1J(CO). While DFT performs well for the geminal couplings 2J(HH) and 2J(CH), it tends to overestimate the vicinal 3J(HH) couplings slightly although it is sufficiently accurate for most purposes.
Electric Multipole Moments and (Hyper)Polarizability of X–C≡C–X, X = F, Cl, Br and I
Authors: Maroulis George , Xenides Demetrios
Published: October 2008

We have calculated self-consistent field (SCF) and second-order Møller-Plesset perturbation theory (MP2) for the dihaloethynes X–C≡C–X, X = F, Cl, Br and I. All calculations have been performed with carefully optimized, flexible basis sets of gaussiantype functions. Our best values for the quadrupole moment (Θ/ea02) are -0.6524 (FCCF), 3.6612 (ClCCCl), 5.8143 (BrCCBr) and 8.3774 (ICCI). The dipole polarizability is strongly anisotropic. For the mean (α /e2a02Eh-1) and the anisotropy (Δα/e2a02Eh-1) we obtain 23.58 and 15.09 (FCCF), 51.75 and 48.30 (ClCCCl), 66.53 and 60.04 (BrCCBr), 93.79 and 78.91 (ICCI). The mean dipole hyperpolarizability (γ /e4a04Eh-3) increases rapidly as 2932 (FCCF), 9924 (ClCCCl), 17409 (BrCCBr) and 35193 (ICCI). The transversal component of the hyperpolarizability is larger than the longitudinal one for FCCF, γxxxx > γzzzz but this is reversed for the other molecules in the series. Difluoroethyne is less (hyper)polarizable than ethyne.
Theoretical Modelling for the Ground State Rotamerisation and Excited State Intramolecular Proton Transfer of 2-(2’-hydroxyphenyl)oxazole, 2-(2’-hydroxyphenyl)imidazole, 2-(2’-hydroxyphenyl)thiazole and Their Benzo Analogues
Authors: Purkayastha Pradipta , Chattopadhyay Nitin
Published: October 2008

Two series of compounds, one comprising of 2-(2′-hydroxyphenyl)benzoxazole (HBO), 2-(2′-hydroxyphenyl)benzimidazole (HBI), 2-(2′-hydroxyphenyl)benzothiazole (HBT), and the other of 2-(2′-hydroxyphenyl)oxazole (HPO), 2-(2′-hydroxyphenyl)imidazole (HPI) and 2-(2′-hydroxyphenyl)thiazole (HPT) are susceptible to ground state rotamerization as well as excited state intramolecular proton transfer (ESIPT) reactions. Some of these compounds show experimental evidence of the existence of two ground state conformers. Out of these two one undergoes ESIPT reaction leading to the formation of the tautomer. The two photophysical processes, in combination, result in the production of a number of fluorescence bands each one of which corresponding to a particular species. Semiempirical AM1-SCI calculations have been performed to rationalize the photophysical behaviour of the compounds. The calculations suggest that for the first series of compounds, two rotational isomers are present in the ground state of HBO and HBI while HBT has a single conformer under similar circumstances. For the molecules of the other series existence of rotamers depends very much on the polarity of the environment. The potential energy curves (PEC) for the ESIPT process in different electronic states of the molecules have been generated theoretically. The simulated PECs reveal that for all these systems the IPT reaction is unfavourable in the ground state but feasible, both kinetically and thermodynamically, in the S1 as well as T1 states.
Specific Features of Intramolecular Proton Transfer Reaction in Schiff Bases
Authors: Koll Aleksander
Published: October 2008

The differences between the intramolecular proton transfer in Mannich and Schiff bases are discussed. The tautomeric forms being in equilibrium in both types of molecules are seriously different. In Mannich bases there are in equilibrium the forms of phenols and phenolates. In Schiff bases each of tautomers is strongly influenced by resonance between zwitterionic and keto structures. Despite the common opinion that the proton transfer forms in compounds with internal π-electronic coupling are mainly keto forms it is shown in this work, that in Schiff bases the content of keto structure is slightly less than zwitterionic one. Almost equal participation of both forms leads to effective resonance between them and stabilization of intramolecular hydrogen bond in this way.
An Acid Exchanged Montmorillonite Clay-Catalyzed Synthesis of Polyepichlorhydrin
Authors: Yahiaoui Ahmed , Belbachir Mohammed , Hachemaoui Aïcha
Published: October 2008

“Maghnite”, a montmorillonite sheet silicate clay, exchanged with protons to produce “H-Maghnite” is an efficient catalyst for cationic polymerisation of many heterocyclic and vinylic monomers (Belbachir, M. U.S. Patent. 066969.0101 –2001). The structural compositions of both “Maghnite” and “H-Maghnite” have already been determined. Epichlorhydrin monomer, which is polymerizable by a cationic process (Odian,G. La Polymerisation: Principes et Applications; Ed.Technica: New York, 1994; pp 222-226), was used to elucidate the polymerization cationic character. The polymerization was performed under optimum conditions at 20°C. Experiments revealed that the polymerisation induced by “H-Maghnite” proceeds in bulk. In bulk polymerization, Epichlorhydrin conversion increases with increasing “H-Maghnite” concentration and temperature.
Proceedings of the 9th Electronic Computational Chemistry Conference
Authors: Topper Robert , Dmitrenko Olga
Published: October 2008

It is our privilege to introduce this special issue of the International Journal of Molecular Sciences, which presents the Proceedings of the 9th Electronic Computational Chemistry Conference (ECCC9).[...]
Exploring QSAR of Non-Nucleoside Reverse Transcriptase Inhibitors by Neural Networks: TIBO Derivatives
Authors: Douali Latifa , Villemin Didier , Cherqaoui Driss
Published: October 2008

Human Immunodeficiency Virus type 1 (HIV-1) reverse transcriptase is an important target for chemotherapeutic agents against the AIDS disease. 4,5,6,7-Tetrahydro-5-methylimidazo[4,5,1-jk][1,4]benzodiazepin-2(1H)-ones (TIBO) derivatives are potent non-nucleoside reverse transcriptase inhibitors (NNRTIs). In the present work, quantitative structure-activity relationship (QSAR) analysis for a set of 82 TIBO derivatives has been investigated by means of a three-layered neural network (NN). It has been shown that NN can be a potential tool in the investigation of QSAR analysis compared with the models given in the literature. NN gave good statistical results both in fitting and prediction processes (0.861 ≤ r² ≤ 0.928, 0.839 ≤q² ≤ 0.845). The relevant factors controlling the anti-HIV-1 activity of TIBO derivatives have been identified. The results are along the same lines as those of our previous studies on HEPT derivatives and indicate the importance of the hydrophobic parameter in modeling the QSAR for TIBO derivatives.