bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparative Molecular Field Analysis of Compounds with CYP2A5 Binding Affinity
Authors: Poso Antti , Juvonen Risto , Gynther Jukka 
Published: October 2006

AbstractSixteen planar coumarin type substrates and inhibitors of cyto‐chrome P4502A5 (CYP2A5) were analyzed using the Comparative Molecular Field Analysis (CoMFA) method [1]. The analysis was carried out using traditional steric and electrostatic fields, the energy of the lowest unoccupied molecular orbital (LUMO) and the highest occupied molecular orbital (HOMO), dipole moment and LUMO as a 3‐D field (square of the wave function). The highest cross‐validated r2‐value (q2), 0.741, was obtained (five PLS components) when steric and electrostatic fields were used together. However, when LUMO field or energy was included in the analyses, q2‐values decreased (0.723 and 0.724, respectively) and the required number of PLS components also decreased to three. In this case the LUMO field most probably reflects structural information not shown in traditional fields. CoMFA contour maps emphasized the importance of the ligands' lactone structure, together with the methoxy group of methoxsalen, for high CYP2A5 binding affinity.
Structural Requirements of the Binding of Nonionic Surfactants to Sodium Dodecylsulfate
Authors: Forgács Esther , Cserhäti Tibor 
Published: October 2006

AbstractThe interaction of 24 nonionic surfactants (6 ethoxylated stearic acid derivatives, 10 ethoxylated fatty alcohols, and 8 ethoxylated anhydrosorbite derivatives) with the anionic surfactant sodium dodecylsulfate (SDS) was studied by reversed‐phase chromatography, and the relative strength of interaction has been calculated. Principal component analysis (PCA) was used for the determination of molecular substructures and physicochemical parameters accounting for the interaction. Each nonionic surfactant interacted with SDS; the relative strength of interaction depended considerably on the molecular structure of surfactants. In each instance the SDS ‐ surfactant complex was less hydrophobic than the surfactant itself. The result of PCA points to the involvement of both hydrophobic and hydrophilic forces in complex formation. The data also indicate that the apolar alkyl chain of SDS is probably bound to the hydrophobic moiety of surfactants, and the polar head group interacts with the hydrophilic ethylene oxide chain of nonionic surfactants. The strong interaction between SDS and nonionic surfactants suggests that this interaction may have a marked influence on the biological efficacy of any pharmaceutical, agrochemical formulations and cosmetics containing simultaneously both types of surfactants.
Processes Underlying Interactions of Human Lactoferrin with the Jurkat Human Lymphoblastic T‐cell Line Receptor. II ‐ Comparative Molecular Field Analysis
Authors: Elass Abdelaziz , Vergoten Gérard , Legrand Dominique , Mazurier Joël , Elass‐Rochard Elisabeth , Spik Geneviève 
Published: October 2006

AbstractIt has previously been established that all or part of residues 4 ‐ 52 of human lactoferrin interact with the specific T‐lymphocyte receptor. Furthermore, the preliminary study using classical quantitative structure‐affinity relationships (QSAR) models have pointed out the importance of some H‐bond donor and acceptor groups of aminoacids in the interactions. In the present paper, comparative molecular field analysis (CoMFA) was used as a three‐dimensional QSAR method to define major steric and electrostatic features of lactoferrin‐T‐lymphocyte interactions. According to steric interaction energies, some residues of human lactoferrin: R3, F20, Q23, R24, S38 and Q47, previously described by the QSAR method, as well as Q21, R27 and R56 look essential for interactions. The results of the electrostatic features study are also in good agreement with the QSAR H‐bonds model and demonstrate that the pHi is a significant binding factor. Taken as a whole, QSAR and CoMFA methods allow to define two regions, potentially involved in selectivity between species, R3, Q7, N13, Q23, R24, S38, Q50 and N55; and binding potency, P14, F20, D43, S44, P45 and Q47.
Structure and dissociation energy of weakly bound H (n = 5−8) complexes
Authors: Seo Hyun‐Il , Sun Ju‐Yong , Shin Chang‐Ho , Kim Seung‐Joon 
Published: October 2006

AbstractThe geometrical parameters, vibrational frequencies, and dissociation energies for H (n = 5–8) clusters have been investigated using high level ab initio quantum mechanical techniques with large basis sets. The highest level of theory employed in this study is TZ2P CCSD(T). The C1 structure of H is predicted to be a global minimum, while the Cs structure of H is calculated to be a transition state. Harmonic vibrational frequencies are also determined at the DZP and TZ2P CCSD levels of theory. The dissociation energies, De, for H (n = 5–8) have been predicted using energy differences at each optimized geometry, and zero‐point vibrational energies (ZPVEs) are considered to compare with experimental values. The dissociation energies (Do) have been predicted to be 1.69, 1.65, 1.65, and 1.46 kcal · mol for H, H, H (C1 symmetry) and H, respectively, at the TZ2P CCSD(T) level of theory. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Quasi‐random integration in quantum chemistry: Efficiency, stability, and application to the study of small atoms and molecules constrained in spherical boxes
Authors: Cuenca D. Zorrilla , Márquez J. Sánchez , Núñez M. Fernández , Huertas R. Rodríguez 
Published: October 2006

AbstractThis project consists of two parts. In the first part, a series of test calculations is performed to verify that the integrals involved in the determination of atomic and molecular properties by standard self‐consistent field (SCF) methods can be obtained through Halton, Korobov, or Hammersley quasi‐random integration procedures. Through these calculations, we confirm that all three methods lead to results that meet the levels of precision required for their use in the calculation of properties of small atoms or molecules at least at a Hartree–Fock level. Moreover, we have ensured that the efficiency of quasi‐random integration methods that we have tested is Halton=Korobov>Hammersley≫pseudo‐random. We also find that these results are comparable to those yielded by ordinary Monte Carlo (pseudo‐random) integration, with a calculation effort of two orders of smaller magnitude. The second part, which would not have been possible without the integration method previously analyzed, contains a first study of atoms constrained in spherical boxes through SCF calculations with basis functions adapted to the features of the problem: Slater‐type orbitals (STOs) trimmed by multiplying them by a function that yields 1 for 0 < r < (R‐δ), polynomial values for (R‐δ) < r < R and null for r > R, R being the radius of the box and δ a variationally determined interval. As a result, we obtain a equation of state for electrons of small systems, valid just in the limit of low temperatures, but fairly simple. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
A metabonomic analysis of plasma from Zucker rat strains using gas chromatography/mass spectrometry and pattern recognition
Authors: Major Hilary J. , Williams Rebecca , Wilson Amy J. , Wilson Ian D. 
Published: October 2006

AbstractPlasma obtained from three strains of Zucker rats was analysed using capillary gas chromatography/mass spectrometry (GC/MS) to obtain global metabolite profiles as part of a series of metabonomic investigations of animal models of diabetes. Samples were obtained from 20‐week‐old male wild‐type Zucker lean, (fa/fa) obese and lean/(fa) animals and were analysed following protein precipitation, using acetonitrile, and derivatisation. Subsequent data analysis using principal components analysis (PCA) and orthogonal projection to latent structures (OPLS) revealed differences between the plasma metabolite profiles of the three strains, with those of the Zucker lean and the lean/(fa) crosses being similar to each other whilst differing from the (fa/fa) obese strain. Copyright © 2006 John Wiley & Sons, Ltd.
Liquid chromatographic/tandem mass spectrometric method for the quantitation of tranilast in human plasma
Authors: Lan Jing , Wang Jian , Wu Dan , Wang Yingwu , Fawcett J. Paul , Gu Jingkai 
Published: October 2006

AbstractAn analytical method for the determination of tranilast in human plasma using tramadol as the internal standard has been developed based on liquid chromatography/tandem mass spectrometry. Sample preparation involved protein precipitation with methanol. Separation by reversed‐phase high‐performance liquid chromatography using methanol/10 mM ammonium acetate (70: 30, v/v) as mobile phase was complete in a run time of 2.4 min. Detection on a Q TRAP™ system used multiple reaction monitoring. The method was linear in the range 0.06–20 µg/mL with intra‐ and inter‐day precisions (as relative standard deviation) of 2.2–2.6% and 2.3–2.9%, respectively. Accuracy (as relative error) was <−2.5%. The method was applied in a pharmacokinetic study in healthy volunteers treated with a single 80 mg oral dose of tranilast. Copyright © 2006 John Wiley & Sons, Ltd.
Tip‐enhanced optical spectroscopy for surface analysis in biosciences
Authors: Hartschuh A. , Qian H. , Meixner A. J. , Anderson N. , Novotny L. 
Published: October 2006

AbstractOptical spectroscopy provides a wealth of information on the electronic and vibronic states of biological materials and surfaces, thus allowing for a detailed analysis of the sample constituents. Furthermore, information on photoprocesses such as excited‐state relaxation, charge transfer and coupling of individual quantum systems, as for example, in light‐harvesting complexes, can also be obtained. Advances in near‐field optics open up new means to overcome the diffraction limit and extend the range of optical measurements to the length scales of most nanosystems. In this paper, we describe a near‐field microscopic technique that relies on the enhanced electric field near a sharp, laser‐irradiated metal tip. This confined light source can be used for highly localized excitation of photoluminescence (PL) and Raman scattering. We study the properties of the enhanced fields and demonstrate PL and Raman imaging of single‐walled carbon nanotubes (SWCNTs) with sub‐15 nm resolution. The existing studies on biomaterials using tip‐enhanced techniques in the literature are reviewed and potential applications together with the requirements on sample materials are discussed. Copyright © 2006 John Wiley & Sons, Ltd.
Uptake and exclusion of plutonium by bacteria isolated from soil near Nagasaki, Japan
Authors: Kauri Tiit , Kauri Tiiu , Santry D. C. , Kudo A. , Kushner D. J. 
Published: October 2006

AbstractThe ability to bind Pu4+ during growth in the presence of low concentrations of this ion was compared in 5 strains of bacteria isolated from soil that had been contaminated with Pu by fallout for more than 40 years. Although Pu became associated with all bacterial strains studied, the strength of association varied greatly. These results suggest that different bacteria use different techniques in dealing with Pu4+ ions. This, in turn, could greatly affect the fate of these ions in natural environments and their subsequent availability for other forms of life.
Absorption, distribution, and elimination of arsenic in New Zealand white rabbits (Oryctalagus cuniculus) following multiple oral doses of monosodium methane arsonate
Authors: Jaghabir Madi Wali , Abdelghani Assa F. A. , Anderson Ann C. 
Published: October 2006

AbstractThis work consisted of uptake and clearance studies resulting from the exposure of arsenic to New Zealand White rabbits. After two weeks' exposure to 5 mg monosodium methane arsonate/kg, the order of arsenic concentration in tissues was kidney > liver > muscle. By the end of four weeks' exposure, redistribution had taken place: liver > kidney > muscle. Arsenic was also detected in the fur (6.36 mg/kg) following four weeks' exposure.Clearance studies showed that arsenic disappeared rapidly in the liver; however, trace amounts were detected in the kidney and the muscle two weeks following termination of continuous exposure. Arsenic was excreted in both urine and feces. Arsenic in rabbit fur showed no indication of elimination during the two weeks following continuous exposure.
Coliphages and other microbial indicators in stabilization ponds
Authors: Castillo G. C. , Trumper B. A. 
Published: October 2006

AbstractColiphages have been reported as promising indicators of viral inactivation in wastewater treatment. Their use in different aquatic environments, however, needs characterization prior to their application. The study of the behavior of coliphages in Chilean stabilization ponds is reported. The experimental system was a discontinuous reactor, subjected to the natural different climate conditions. Chile is a temperate country and this study concentrated on the significantly different behavior of ponds during summer and fall seasons. Coliphages counts using Escherichia coli C (ATCC 13706) as host were compared to most probable number fecal coliforms, Salmonella, and fecal streptococci. The results indicate that coliphages were more resistant to pond treatment than fecal coliforms and Salmonella. Furthermore, coliphages did not reflect climate changes as much as enteric bacteria did, as coliphage die‐off rates during warm and cold seasons were 0.5 and 0.3 (Kb, day−1). Summer die‐off rates of fecal coliforms (2.0, Kb, day−1) and Salmonella (1.7, Kb, day−1) drastically fell (0.6, Kb, day−1) in the fall. Coliphages and fecal streptococci removal tended to be similar, especially in cold season. It was observed that environmental factors, pH, dissolved oxygen, and algae biomass equally affected removal of all indicators, to different extents. These results suggest that to assess the microbiological efficiency of stabilization ponds, coliphages and fecal coliforms should be considered, as the first represents viral removal while the second represents pathogenic bacterial removal. Both parameters complement each other, particularly when important weather changes are expected.
Microbial purification in slow sand filter
Authors: Datta Amal K. , Chaudhuri Malay 
Published: October 2006

AbstractLaboratory slow sand filter was characterized in terms of variation in catalase activity and standard plate count with depth as well as its effectiveness in inactivation of enteric microorganisms, using Escherichia coli as a model. The term inactivation was used to describe the overall process of removal/inactivation of enteric microorganisms in the filter, including predation, antagonism, etc. The following equation was proposed and used to estimate the inactivation potential of various filter bed depths from data on decay of E. coli in reactors with sand microorganism suspension from corresponding depths: dN/dt = −kN −(pG)N, in which N is the population of E. coli in reactor at time t, k is the decay rate of E. coli in control reactor, p is the inactivation potential, and G is the weight of sand sample corresponding to the sand microorganism suspension inoculum. Efforts were also made to examine the relative role of procaryotes and eucaryotes in the inactivation. It was observed that a matured filter bed was well populated throughout with active microorganisms, with its maximum in the top 10 or 25‐cm layer. Distribution of the population was independent of the rate of filtration. In general, the top 10 or 25 cm of the filter bed supported a microbial population that contributed most significantly to inactivation of E. coli.; the entire bed, however, was active in such inactivation. Both procaryotes and eucaryotes were active in the filter, with procaryotes more dominant near the top surface.
Contamination of domestic water heaters with Legionella pneumophila: Impact of water temperature on growth and dissemination of the bacterium
Authors: Dewailly E. , Joly Jean R. 
Published: October 2006

AbstractSediment and tap water from 255 randomly selected domestic water heaters were cultured on buffered charcoal yeast extract agar and two semiselective media to detect the presence of Legionellaceae. Different serogroups of L. pneumophila, the only species of Legionellaceae identified in this study, were found in 84 of the 255 water heaters and this contamination occurred only in electric water heaters (n = 205).Sediment contamination by L. pneumophila was strongly associated with water temperature. The bacterium was detected in 45% (80/176) of the sediments with temperature lower than 40°C and in only 14% (4/29) of the sediments at this or higher temperatures. When the peripheral water temperature was lower than 56°C, 23% (9/39) of the tap water samples were contaminated with Legionella while only one of the 161 samples that were above this temperature contained Legionella.These results do suggest that reducing the water temperature in electric water heaters could play a role in the multiplication of L. pneumophila in the water heaters and in its dissemination in the household.
A multiparameter chemical toxicity test using Salmonella typhimurium and Spirochaeta aurantia
Authors: Kupillas Gregory E. , Pill Kenneth G. , Picardal Flynn W. , Arnold Robert G. 
Published: October 2006

AbstractA battery of measurements, including specific growth rate, intracellular ATP level, and respiration rate, was designed to measure the responses of Salmonella typhimurium and Spirochaeta aurantia to chemical toxicants. The test battery provided both a measure of relative toxicity and an indication of the biochemical mechanism of chemical toxicity.The utility of the battery was investigated using chemicals (cyanide, 2,4‐dinitrophenol, chloramphenicol, and dicyclohexylcarbodiimide) for which toxic mechanisms have been clearly established. Test battery results provided a reproducible “signature” for each model compound, which was useful for differentiating among compounds whose primary mechanism of toxicity involves (a) inhibition of catabolic activity leading to oxidative phosphorylation, (b) disruption of membrane integrity, and (c) interference with biosynthetic activity. The responses of the two test organisms to model inhibitors were qualitatively identical and paralleled predictions based on theoretical grounds.In theory, the test battery can measure toxicity among classes of compounds that alternative, single‐parameter microbial tests would classify as nontoxic. The microbial test battery described may eventually provide a theoretically superior and economically attractive alternative to established toxicity testing procedures.
Testing the influence of chemicals on soil autotrophic ammonium oxidation
Authors: Hansson G.‐B. , Klemedtsson L. , Stenström J. , Torstensson L. 
Published: October 2006

AbstractNitrification is crucial for the content of inorganic nitrogen in soil and hence of considerable ecological and agricultural importance. The first step in the nitrification process, the oxidation of ammonium to nitrite, is particularly sensitive to chemicals, and the ammonium oxidation activity of soils may thus be used as an indicator of chemical disturbances. A method for the determination of potential nitrification has been tested that measures ammonium oxidation specifically and under optimal conditions, has a good reproducibility, and makes it possible to screen a large number of chemicals during a short period of time. The method has been tested with a number of pesticides. Dithio‐carbamate fungicides gave the most pronounced inhibition of ammonium oxidation.
Fast method for detecting toxic Cyanophyte blooms
Authors: Volterra L. , Bruno M. , Gucci P. M. B. , Pierdominici E. 
Published: October 2006

AbstractOwing to Cyanophytes, toxic blooms may originate in drinking water supplies. Since it is vitally important for human health that such blooms are rapidly identified and treatment plant for water potabilization is readily adapted, we have performed experiments aiming at assessing the usefulness of Microtox™ as a tool for detecting biotoxins caused by Cyanobacteria as rapidly as possible. Comparison between instrumental results and data obtained with Microtox has shown a discrepancy, but has also pointed out Microtox's sensitivity and therefore its application in monitoring Cyanophyte blooms in order to detect algal biotoxins, whose chemical characterization requires further examination following identification by the Microtox system.
Firefly assay of ATP from freshwater zooplankton: Comparison of extraction methods
Authors: Amyot M. , Pinel‐Alloul B. , Bastien C. , Méthot G. , Blaise C. , van Coillie R. , Thellen C. 
Published: October 2006

AbstractInvestigations were conducted to compare the efficiency of adenosine triphosphate (ATP) extraction from freshwater zooplankton species (Skistodiaptomus oregonensis, Tropocyclops prasinus mexicanus, Daphnia magna, and Bosmina longirostris) using DMSO and cold H2SO4 extraction procedures. DMSO was found to extract more ATP (particularly in copepod species) while cold H2SO4 provided more consistent results. Homogenization by grinding samples during extraction was shown to be a very important step. Juvenile and adult specimens of D. magna were extracted. Adults gave higher ATP values. The necessity for a 24‐h acclimation period was tested. Although acclimation appeared to provide more consistent results, no marked lowering of ATP level in organisms was registered without acclimation. No unique method was found to be optimal for all studied species. © 1992 John Wiley & sons, Inc.
Bioaccumulation and depuration of ethylene glycol by crayfish (procambarus spp.)
Authors: Khoury Ghassan A. , Abdelghani Assaf A. , Anderson Ann C. 
Published: October 2006

AbstractCrayfish were exposed to 50, 200, or 1000 μg/mL ethylene glycol (EG) daily for 61 days, and were subsequently transferred to clean water for a 67‐day decontamination phase. During uptake and loss, samples were analyzed for EG in gills, muscle, gastrointestinal tract, and hepatopancreas. An open one‐compartment mathematical model described the uptake and loss phases data.Uptake was dependent upon the aqueous concentration of EG. Crayfish did not concentrate EG above the water concentration. Bioaccumulation factors for the selected tissues at 61 days of exposure to 50, 200, and 1000 μg/mL EG, respectively were as follows: 0.40, 0.21, and 0.21 for gills; 0.48, 0.21, and 0.21 for muscle; 0.61, 0.42, and 0.27 for gastrointestinal tract; and 0.60, 0.33, and 0.22 for hepatopancreas. Time to equilibrium was 5,4,5, and 4 days for gills, muscle, gastrointestinal tract, and hepatopancreas, respectively, at 50 μg/mL aqueous concentration; 5, 4, 6, and 4 days, respectively, at 200 μg/mL aqueous concentration; and 7, 5, 7, and 5 days, respectively, at 1000 μg/mL aqueous concentration.Crayfish eliminated the accumulated EG within 5 days for animals exposed to 50 μg/mL EG and 6 days for those exposed to 200 and 1000 μg/mL EG. © 1993 John Wiley & Sons, Inc.
Effect of copper, herbicides, and a mixed effluent on chemoattraction of tetrahymena pyriformis
Authors: Roberts Robert O. , Berk Sharon G. 
Published: October 2006

AbstractThe inhibitory effect of copper, 2,4‐D, Roundup, and an industrial effluent on chemoattraction responses of the ciliate Tetrahymena pyriformis was examined using a microcapillary technique. Each toxicant was tested with four replicates on three separate occasions. All toxicants inhibited chemoattraction at sublethal concentrations; although at lower concentrations of the herbicides, complete recovery to control levels was observed with longer exposures.Results indicate that sublethal concentrations of certain chemical pollutants may interfere with the ciliate's motility or chemosensory abilities. This may ultimately affect the ecosystem by inhibiting their ability to maintain their population levels and roles in the environment.