bluuebunny/crossref_metadata_2025_split huggingface dataset:
Helix‐coil transition of PrP106–126: Molecular dynamic study
Authors: Levy Yaakov , Hanan Eilat , Solomon Beka , Becker Oren M. 
Published: August 2002

AbstractA set of 34 molecular dynamic (MD) simulations totaling 305 ns of simulation time of the prion protein‐derived peptide PrP106–126 was performed with both explicit and implicit solvent models. The objective of these simulations is to investigate the relative stability of the α‐helical conformation of the peptide and the mechanism for conversion from the helix to a random‐coil structure. At neutral pH, the wild‐type peptide was found to lose its initial helical structure very fast, within a few nanoseconds (ns) from the beginning of the simulations. The helix breaks up in the middle and then unwinds to the termini. The spontaneous transition into the random coil structure is governed by the hydrophobic interaction between His111 and Val122. The A117V mutation, which is linked to GSS disease, was found to destabilize the helix conformation of the peptide significantly, leading to a complete loss of helicity approximately 1 ns faster than in the wild‐type. Furthermore, the A117V mutant exhibits a different mechanism for helix‐coil conversion, wherein the helix begins to break up at the C‐terminus and then gradually to unwind towards the N‐terminus. In most simulations, the mutation was found to speed up the conversion through an additional hydrophobic interaction between Met112 and the mutated residue Val117, an interaction that did not exist in the wild‐type peptide. Finally, the β‐sheet conformation of the wild‐type peptide was found to be less stable at acidic pH due to a destabilization of the His111–Val122, since at acidic pH this histidine is protonated and is unlikely to participate in hydrophobic interaction. Proteins 2001;45:382–396. © 2001 Wiley‐Liss, Inc.
Aversion of the feral pigeon and the house sparrow to pellets and sprouts treated with commercial formulations of methyl anthranilate
Authors: Moran Shmuel 
Published: August 2002

AbstractTwo methyl anthranilate formulations, ReJex‐iT® TP‐40 and AG‐36, were tested as bird‐repelling agents for animal feed and vegetable sprouts, respectively. Feral pigeons (Columba livia) and house sparrows (Passer domesticus) are important pests of animal husbandry and field crops in Israel. In each 4‐day experiment, four birds were held together in an aviary, and were offered four trays or dishes with animal feed or cauliflower sprouts in four corners of the cage. The trays and dishes were transposed daily in a Latin square sequence. Pigeons consumed significantly more untreated feed than treated feed. When no alternative untreated food was offered, there was no significant repellency. Treatment of animal feed with TP‐40 to give 2.0 ml methyl anthranilate kg−1 or less had no repellent effect on sparrows. Concentrations of 4.0 ml kg−1 or more repelled the sparrows significantly. When no untreated feed was presented, pigeons and sparrows preferred the lowest concentration of methyl anthranilate presented. When AG‐36 was tested on vegetable sprouts, the sparrows tended significantly to avoid the highest concentration used—14.5 ml methyl anthranilate litre−1 spray. The inter‐specific differences between the birds indicate that the efficacy of methyl anthranilate formulations as a repellent has to be specified for every species. This study did not determine (1) the possibility of developing habituation, (2) the behaviour of birds under natural conditions in the field, or (3) the influence of the feeding behaviour of a sympatric bird species on the repellency of methyl anthranilate to other species.© 2001 Society of Chemical Industry
Viability and stability of biological control agents on cotton and snap bean seeds
Authors: Elliott Monica L , Jardin Elizabeth A Des , Batson William E , Caceres Jacobo , Brannen Philip M , Howell Charles R , Benson D Michael , Conway Kenneth E , Rothrock Craig S , Schneider Raymond W , Ownley Bonnie H , Canaday Craig H , Keinath Anthony P , Huber Donald M , Sumner Donald R , Motsenbocker Carl E , Thaxton Peggy M , Cubeta Marc A , Adams Pamela D , Backman Paul A , Fajardo Julius , Newman Melvin A , Pereira Roberto M 
Published: August 2002

AbstractCotton and snap bean were selected for a multi‐year, multi‐state regional (south‐eastern USA) research project to evaluate the efficacy of both commercial and experimental bacterial and fungal biological control agents for the management of damping‐off diseases. The goal for this portion of the project was to determine the viability and stability of biological agents after application to seed. The biological seed treatments used included: (1) Bacillaceae bacteria, (2) non‐Bacillaceae bacteria, (3) the fungus Trichoderma and (4) the fungus Beauveria bassiana. Seed assays were conducted to evaluate the following application factors: short‐term (≤3 months) stability after seed treatment; quality (ie isolate purity); compatibility with chemical pesticides and other biocontrol agents; application uniformity between years and plant species. For the bacterial treatments, the Bacillaceae genera (Bacillus and Paenibacillus) maintained the greatest population of bacteria per seed, the best viability over time and the best application uniformity across years and seed type. The non‐Bacillaceae genera Burkholderia and Pseudomonas had the least viability and uniformity. Although Beauveria bassiana was only evaluated one year, the seed fungal populations were high and uniform. The seed fungal populations and uniformity for the Trichoderma isolates were more variable, except for the commercial product T‐22. However, this product was contaminated with a Streptomyces isolate in both the years that it was evaluated. The study demonstrated that Bacillaceae can be mixed with Trichoderma isolates or with numerous pesticides to provide an integrated pest control/growth enhancement package.© 2001 Society of Chemical Industry
Baseline toxicity of several pesticides to Hyaliodes vitripennis (Say) (Hemiptera: Miridae)
Authors: Bostanian Noubar J , Larocque Nancy , Chouinard Gérald , Coderre Daniel 
Published: August 2002

AbstractHyaliodes vitripennis (Say) is a univoltine indigenous predacious mirid. It has been reported in several orchards where IPM programmes are used. It is a generalist, and feeds on phytophagous mites in addition to other arthropods. In Quebec, a foliar application of imidacloprid, deltamethrin or lambda‐cyhalothrin is used at least once per season to manage arthropod pests such as leafhoppers and leaf‐eating caterpillars. Meanwhile, several applications of metiram, flusilazole, myclobutanil and mancozeb are made to control apple scab [Venturia inaequalis (Cooke) Winter]. In laboratory trials, comparison of lethal concentrations of the three insecticides against H vitripennis nymphs and adults showed no significant difference. However, when lethal concentrations were compared between two growth stages for each insecticide, a significant difference was noted between adults and nymphs treated with lambda‐cyhalothrin, adults being more susceptible than nymphs. No such difference could be detected for imidacloprid or deltamethrin. When LC50 values were compared with the manufacturer's label rates, deltamethrin and imidacloprid were toxic to the nymphs and adults, and lambda‐cyhalothrin was slightly toxic to the nymphs and moderately toxic to the adults. Among the fungicides evaluated in the laboratory, myclobutanil showed moderate toxicity to adults at the manufacturer's label rate. The remaining fungicides had no toxic effects to adults or nymphs, even at four times the manufacturer's label rate.© 2001 Society of Chemical Industry
Predominant torsional forms adopted by oligopeptide conformers in solution: parameters for molecular recognition
Authors: Marshall Neil J. , Grail Barry M. , Payne John W. 
Published: August 2002

AbstractIn this paper, we describe the predominant conformational forms adopted by tripeptides and higher oligopeptides in aqueous solution. About 50 tripeptides and almost 20 higher oligopeptides (4–6 residues) were subjected to conformational analysis using SYBYL Random Search. As with dipeptides (Grail BM, Payne JW. J. Peptide Sci. 2000; 6: 186–199), both tripeptides and higher oligopeptides were found to occupy relatively few combinations of psi–phi space that were distinct from those associated with predominant protein secondary structures (e.g. helices and β‐sheets). Again, the preferred psi (ψ) values for the first residue (i−1) were in sectors encompassed by the ranges from +150° to ±180°, +60° to +90° and −60° to −90°, which were combined with preferred phi (ϕ) values for the second residue (i) in sectors with ranges from −150° to ±180°, −60° to −90° and +30° to +60°. It was notable that tripeptides and, to a greater extent, higher oligopeptides adopted an initial psi (ψ) (Tor2) from +150° to ±180°. For tripeptides, their N–C distances (distance between N‐terminal nitrogen and C‐terminal carbon atoms) distribute about 6.5 Å to give shorter, ‘folded’ conformers that are similar in length to dipeptides, and longer, ‘extended’ conformers that are distinct. Furthermore, for higher oligopeptides, their N–C distances did not increment in relation to their increasing number of residues and short, ‘folded’ conformers were still present. These findings have a bearing upon the recognition of these molecules as substrates for widely distributed peptidases and peptide transporters. Copyright © 2001 European Peptide Society and John Wiley & Sons, Ltd.
Risk assessment and management of offshore structures
Authors: G Bea Robert 
Published: August 2002

AbstractDuring the past 30 years, reliability‐based risk assessment and management processes have been developed and applied in assessing and maintaining the integrity of a worldwide infrastructure of offshore structure systems. These systems are characterized as a combination of structures, hardware/equipment, operating personnel, organizations, environments and the interfaces between these components. Background on current and future trends in development of comprehensive programs to help improve the quality and reliability of offshore structure systems are outlined. The importance and characteristics of human and organizational factors are discussed. A combination of proactive, reactive and interactive approaches have been developed that employ three strategies to achieve desirable quality and reliability: reduce likelihood of malfunctions, increase detection and correction of malfunctions, and decrease the effects and consequences of malfunctions. System robustness and fail‐safe design are key elements of the third strategy.
Inhibitory effects of aromatic herbs on lipid peroxidation and protein oxidative modification of mice brain homogenate by copperin vitro
Authors: Toda Shizuo 
Published: August 2002

AbstractSeveral aromatic herbs were inferred to have inhibitory effects on the generation of oxygen free radicals. It has been demonstrated that free radicals produced by copper produce lipid peroxidation and protein oxidative modification in the brain. The results presented here showed that several aromatic herbs, Caryophylli flos, Cinnamomi cortex, Foeniculi fructus and Zedoariae rhizoma, have inhibitory effects on lipid peroxidation or protein oxidative modification of mice brain homogenate produced by copper in vitro. Copyright © 2001 John Wiley & Sons, Ltd.
What's new?
Authors: Bohaychuk Wendy 
Published: August 2002

AbstractThe What's New? section in the Quality Assurance Journal aims to draw your attention to items of importance to QA professionals. Each item will be linked to the relevant internet address which you might add to your ‘favorites’ folders. If there is any other new information which should be brought to the attention of readers, please let us know by e‐mailing gcrpc@compuserve.com Copyright © 2001 John Wiley & Sons, Ltd.
Standard operating procedures for clinical research personnel – part 9
Authors: Bohaychuk Wendy , Ball Graham 
Published: August 2002

AbstractThis is the ninth in a series of articles containing proposals for wording and content of standard operating procedures (SOPs) for clinical research activities conducted by sponsors and Contract Research Organisations (CROs). The procedures include those required by the International Conference on Harmonisation (ICH), the Food and Drug Administration (FDA), many other guidelines and regulations, and ‘best practice’ observed by the authors. The model forms require modification for actual use. In this article, SOPs are presented for the initial selection process for suitable study sites (SOP 315), study site selection visits (SOP 316), assessment of Phase I facilities (SOP 317), documentation of qualifications of investigators and other site personnel (SOP 318) and final authorisation to use a study site (SOP 319). (The full text of all 101 SOPs is available from the authors.) Copyright © 2001 John Wiley & Sons, Ltd.
On the reliability of the estimated incapability index
Authors: Pearn W. L. , Lin G. H. 
Published: August 2002

AbstractGreenwich and Jahr‐Schaffrath (1995) introduced the process incapability index $C_{\rm pp}= C_{\rm ip}+ C_{\rm ia}$, which provides an uncontaminated separation between information concerning the process precision $(C_{\rm ip})$ and process accuracy $(C_{\rm ia})$. In this paper, we consider the three indices, and investigate the statistical properties of their natural estimators. For the three indices, we obtain their UMVUEs and MLEs, and compare the reliability of the two estimators based on the relative mean square errors. In addition, we construct 90%, 95%, and 99% upper confidence limits, and the maximum values of $\hat{C}_{\rm pp}$ for which the process is capable 90%, 95%, and 99% of the time. The results obtained in this paper are useful to the practitioners in choosing good estimators and making reliable decisions on judging process capability. Copyright © 2001 John Wiley & Sons, Ltd.
Evaluation of two‐center overlap and nuclear attraction integrals over Slater‐type orbitals with integer and noninteger principal quantum numbers
Authors: Özdoğan T. , Orbay M. 
Published: August 2002

AbstractA general formula has been established for the expansion of the product of two normalized associated Legendre functions centered on the nuclei a and b. This formula has been utilized for the evaluation of two‐center overlap and nuclear attraction integrals over Slater‐type orbitals (STOs) with integer and noninteger principal quantum numbers. The formulas given in this study for the evaluation of two‐center overlap and nuclear attraction integrals show good rate of convergence and great numerical stability under wide range of quantum numbers, orbital exponents, and internuclear distances. © 2001 Wiley Periodicals, Inc. Int J Quantum Chem, 2001
Relationship between the energy of donor–acceptor bond and the reorganization energy in molecular complexes
Authors: Timoshkin A. Y. , Davydova E. I. , Sevastianova T. N. , Suvorov A. V. , Schaefer H. F. 
Published: August 2002

AbstractDonor–acceptor complexes of silicon halides with ammonia, pyridine, and 2,2′bipyridine SiX4 · nD (X = F, Cl, Br) have been studied at the B3LYP/pVDZ level of theory. Energies of the donor–acceptor bond have been estimated taking into account the reorganization energy of the donor and acceptor fragments and basis set superposition error correction. Despite of the very low (or even negative) dissociation energy of SiX4 · nD into free fragments, the Si–N bonding in all complexes is rather strong (75–220 kJ mol−1). It is the reorganization energy of the acceptor SiX4 (75–280 kJ mol−1) that governs the dissociation energy of the complex. Thus, in contrast to the complexes of group 13 halides, the reorganization effects are crucial for the complexes of group 14 halides, and their neglecting leads to erroneous conclusions about the strength of the donor–acceptor bond in these systems. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002
Equilibrium geometry and gas‐phase proton affinity of 2‐thiouracil derivatives
Authors: Moustafa H. , El‐Taher S. , Shibl M. F. , Hilal Rifaat 
Published: August 2002

AbstractThe ground‐state geometries of uracil, 6‐hydroxy‐uracil, and 6‐hydroxy‐, 6‐amino‐, 6‐methyl‐, 6‐trifluoro‐, and 6‐phenyl‐2‐thiouracil were optimized at the Hartree–Fock level. The molecular structures were fully optimized using the 6‐31G and 6‐31G* basis sets. The effect of substituents on the geometry and electronic structural features of 2‐thiouracils were examined. The perturbation effects of the OH and NH2 groups are by far more pronounced on the geometric features and the dipole moment magnitude and direction of 2‐thiouracil. The potential energy per atom criteria was used to compare the relative tightness of binding in the studied series. Proton affinity and deprotonation enthalpy on each of the possible sites in 2‐thiouracil and its derivatives have been calculated at the 6‐31G/MP2 level of theory. The obtained results show that thiouracils behave as bases where they possess a high tendency to abstract protons. Substituents in the 6‐position have the general effect of enhancing the basicity strength of the thiocabonyl site in the order Ph < CH3 ≈ NH2 < OH. The CF3 group has the effect of reducing considerably the basicity strength and enhances the acidity strength at both N1 and N3. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002
Modeling of vibronic interaction and chaotic dynamics in electronic and nuclear subsystems of molecules
Authors: Morozov V. A. , Dubina Y. M. 
Published: August 2002

AbstractThe interaction of electronic and nuclear subsystems of a molecular system is described to be a consequence of cubic and biquadratic coupling on coordinates between electronic and nuclear oscillators in the classic and mixed quantum–classic models of a molecule. The simple relationships between two parameters of nonlinearity and usually used in the description of adiabatic vibronic interaction in a real molecules a shift of equilibrium position of nuclei and change of force constant them harmonic vibrations upon electronic excitation of a molecule are established. It is shown that performance of these relationships averaged on “fast” time dynamics of excitation of electronic oscillators of the classic model coincides with dynamics of population of the excited electronic state of the mixed quantum–classic model for any values of nuclear positions. The influence considered vibronic interaction on the character of dependence of quasienergies of a molecule dressed by a cloud of photons from the coordinate nuclear oscillator is investigated. As a necessary condition for the appearance of chaotic dynamics of nuclei in the considered quantum–classic model of a molecule at transformation by its light fields it is proposed to consider the occurrence of two‐well quasienergy. Taking account this criterion, it is shown that only the considered cubic (but not biquadratic) vibronic interaction is one of the reasons for the chaotic dynamics of nuclei in molecules interacting with a light field. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002
Electronic excitation in anionic polymerization of butadiene: Nonempirical calculations of reaction complexes
Authors: Kalninsh K. K. , Podolsky A. F. 
Published: August 2002

AbstractA new mechanism of anionic polymerization of butadiene is proposed. In the elementary chemical act, the “living” polymer–monomer complex is excited into the low‐lying triplet state. This state has the character of charge (electron) and cation (Li+ or Na+) transfer from the terminal unit of the active center to the monomer molecule. In the framework of this concept, the probability of chemical bond formation is determined by spin density on radical centers of reagent molecules. Semiempirical and ab initio 6‐31G** quantum‐chemical calculations showed stable interaction between components of the complex in the ground electronic state (9–11 kcal/mol) and low energy levels of triplet excited states (<14 kcal/mol). This new approach is shown to be useful in the analysis of polymerization kinetics and the microstructure of polybutadiene depending on the cation type and the ion pair state. The mechanism of cis‐trans isomerization in the terminal unit of the living polymer consists in concerted rotation about the CβCγ bond and the migration of Li between Cα and Cγ atoms. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002
Quantum mechanics of solvated complexes: A test for positronium
Authors: Chuev Gennady N. , Schrader D. M. , Stepanov Sergey V. , Byakov Vsevolod M. 
Published: August 2002

AbstractA hybrid quantum mechanics/molecular mechanics approach is developed for calculating properties of solvated complexes. The method is based on self‐consistent calculations of the Kohn–Sham equations for electronic wave functions and integral equations for solvent structure. The method is applied to solvated positronium (Ps). Using a simple parameterization for the Ps wave function, we calculate the local solvent structure around a hydrated Ps. The results are consistent with the experimental data. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002
Symmetrization of eigenfunctions of angular momentum in point groups
Authors: Li An Yong , Liao Mu Zhen 
Published: August 2002

AbstractThe eigenfunctions |jm〉 of angular momentum can combine linearly to make basis functions of irreducible representations of point groups. We surmount the projection operator and find a new method to calculate the combination coefficients. It is proven that these coefficients are components of eigenvectors of some hermitian matrices, and that for all pure rotation point groups, the coefficients can be made real numbers by properly choosing the azimuth angles of symmetry elements of point groups in the coordinate system. We apply the coupling theory of angular momentum to obtain the general formulas of the basis functions of point groups. By use of our formulas, we have calculated the basis functions with half‐integers j from 1/2 to 13/2 of double‐valued irreducible representations for the icosahedral group. © 2001 John Wiley & Sons, Inc. Int J Quant Chem 83: 286–302, 2001
Rapid bioanalysis of vancomycin in serum and urine by high‐performance liquid chromatography tandem mass spectrometry using on‐line sample extraction and parallel analytical columns
Authors: Cass Robert T. , Villa Josephine S. , Karr Dane E. , Schmidt Donald E. 
Published: August 2002

AbstractA novel high‐performance liquid chromatography tandem mass spectrometry (LC/MS/MS) method is described for the determination of vancomycin in serum and urine. After the addition of internal standard (teicoplanin), serum and urine samples were directly injected onto an HPLC system consisting of an extraction column and dual analytical columns. The columns are plumbed through two switching valves. A six‐port valve directs extraction column effluent either to waste or to an analytical column. A ten‐port valve simultaneously permits equilibration of one analytical column while the other is used for sample analysis. Thus, off‐line analytical column equilibration time does not require mass spectrometer time, freeing the detector for increased sample throughput. The on‐line sample extraction step takes 15 seconds followed by gradient chromatography taking another 90 seconds. Having minimal sample pretreatment the method is both simple and fast. This system has been used to successfully develop a validated positive‐ion electrospray bioanalytical method for the quantitation of vancomycin. Detection of vancomycin was accurate and precise, with a limit of detection of 1 ng/mL in serum and urine. The calibration curves for vancomycin in rat, dog and primate were linear in a concentration range of 0.001–10 µg/mL for serum and urine. This method has been successfully applied to determine the concentration of vancomycin in rat, dog and primate serum and urine samples from pharmacokinetic and urinary excretion studies. Copyright © 2001 John Wiley & Sons, Ltd.