bluuebunny/crossref_metadata_2025_split huggingface dataset:
Coordination topology and stability for the native and binding conformers of chymotrypsin inhibitor 2
Authors: Baysal Canan , Atilgan Ali Rana 
Published: August 2002

AbstractWe demonstrate that the stabilization of the binding region is accomplished at the expense of a loss in the stability of the rest of the protein. A novel molecular mechanics (MM) approach is introduced to distinguish residue stabilities of proteins in a given conformation. As an example, the relative stabilities of folded chymotrypsin inhibitor 2 (CI2) in unbound form, and CI2 in complex with subtilisin novo is investigated. The conformation of the molecule in the two states is almost identical, with an ∼0.6‐Å root‐mean‐square deviation (RMSD) of the Cα atoms. On binding, the packing density changes only at the binding loop. However, residue fluctuations in the rest of the protein are greatly altered solely due to those contacts, indicating the effective propagation of perturbation and the presence of remotely controlling residues. To quantify the interplay between packing density, packing order, residue fluctuations, and residue stability, we adopt an MM approach whereby small displacements are inserted at selected residues, followed by energy minimization; the displacement of each residue in response to such perturbations are organized in a perturbation‐response matrix L. We define residue stability λi = ∑jLij/∑j Lji as the ratio of the amount of change to which the residue is amenable, to the ability of a given residue to induce change. We then define the free energy associated with residue stability, ΔGλ = −RT ln λ. ΔGλ intrinsically selects the residues that are in the folding core. Upon complexation, the binding loop becomes more resistant to perturbation, in contrast to the α‐helix that favors change. Although the two forms of CI2 are structurally similar, residue fluctuations differ vastly, and the stability of many residues is altered upon binding. The decrease in entropy introduced by binding is thus compensated by these changes. Proteins 2001;45:62–70. © 2001 Wiley‐Liss, Inc.
Activity against plant pathogenic fungi of phomalactone isolated fromNigrospora sphaerica
Authors: Kim Jin‐Cheol , Choi Gyung Ja , Park Joong‐Hyeop , Kim Heung Tae , Cho Kwang Yun 
Published: August 2002

AbstractPhomalactone, 5,6‐dihydro‐5‐hydroxy‐6‐prop‐2‐enyl‐2H‐pyran‐2‐one, produced by the fungusNigrospora sphaerica, was testedin vitroagainst nine plant pathogenic fungi, and specifically inhibited the mycelial growth ofPhytophthora infestans, with an MIC value of 2.5 mg litre−1. Its inhibitory activities against sporangium and zoospore germination ofP infestanswere similar to those againstPhytophthora capsici. In vivo, at 100 and 500 mg litre−1, it reduced the development of tomato late blight caused byP infestans.© 2001 Society of Chemical Industry
In vivo pharmacokinetics of pyribenzoxim in rats
Authors: Liu Kwang‐Hyeon , Moon Joon‐Kwan , Sung Ha‐Jung , Kang Seung‐Hun , Koo Suk‐Jin , Lee Hye‐Suk , Kim Jeong‐Han 
Published: August 2002

AbstractPyribenzoxim, benzophenone O‐[2,6‐bis(4,6‐dimethoxypyrimidin‐2‐yloxy)benzoyl]oxime, is a new post‐emergence herbicide providing broad‐spectrum weed control in rice fields. [14C]Pyribenzoxim was used to study the pharmacokinetics of the compound after oral administration of a dose of 1000 mg kg−1 to male Sprague–Dawley rats. The material balance ranged from 97.3 to 99.7% of the administered dose and urinary and fecal recovery accounted for 97.1%, with the majority of radioactivity recovered in feces (88.6%) by 168 h after treatment. Elimination as volatile products or as carbon dioxide was negligible. The following values were obtained for the compound in the blood: AUC0–168h, 28400 µg equiv h g−1; Tmax, 12 h; Cmax, 372 µg equiv g−1; half‐life, 53 h. Radioactivity in tissue decreased from 96.1% of applied radiocarbon at 6 h to 0.4% at 168 h and the highest concentration of radioactivity among the tissues was observed in liver while the lowest residues were found in brain. The elimination half‐lives of radioactivity from tissues was in the range of 7 to 77 h and Tmax values of 12, 24 and 12 h were observed for blood, liver and kidney, respectively. Except for that in the digestive tract, the tissue‐to‐blood ratio (TBR) was highest in the liver.© 2001 Society of Chemical Industry
Latent production of angiotensin I‐converting enzyme inhibitors from buckwheat protein
Authors: Li Chun‐Hui , Matsui Toshiro , Matsumoto Kiyoshi , Yamasaki Rikio , Kawasaki Terukazu 
Published: August 2002

AbstractThe latent production of angiotensin I‐converting enzyme (ACE) inhibitors from tartary buckwheat (BW) was investigated, and the peptides responsible for ACE inhibition characterized. Intact buckwheat was found to exhibit ACE inhibitory activity having an IC50 value of 3.0 mg/ml. The activity of the protein fraction (IC50: 0.36 mg protein/ml) was not enhanced by pepsin treatment. Pepsin, followed by chymotrypsin and trypsin hydrolysis, resulted in a significant increase in the ACE inhibitory activity (IC50: 0.14 mg protein/ml). The rutin contained in the buckwheat did not exhibit any ACE inhibition. A single oral administration of BW digest lowered the systolic blood pressure of a spontaneously hypertensive rat. Thus, BW proteins offer a potential resource for producing ACE inhibitory peptides during the digestion process. From the di‐/tri‐peptide fraction (DTPF) of the BW digest, inhibitory peptides were identified. The magnitude (%) of the total ACE inhibitory contribution of each identified peptide, relative to the overall inhibition of the DTPF, was about 41%. Copyright © 2002 European Peptide Society and John Wiley & Sons, Ltd.
Contraceptive effects of Phyllanthus amarus in female mice
Authors: Rao Mandava V. , Alice Kurian M. 
Published: August 2002

AbstractAntifertility effects of an alcohol extract of the whole plant, Phyllanthus amarus at a dose of 100 mg/kg body weight for 30 days orally was investigated in cyclic adult female mice. The results revealed no ­significant change in absolute body and organ weights in extract‐fed animals, indicating no alteration in general metabolic status. Further, feeding had no effect on haematological and clinical biochemical tests reflecting its non‐toxicity. Similarly, uterine and ovarian biochemical tests showed no change except in 3β and 17β hydroxy steroid dehydrgenase (HSDs) levels, probably affecting hormonal conversions in the latter. Cohabited females with normal male mice were unable to become pregnant as their cyclicity was affected. These factors are related to a change in the hormonal milieu that governs female reproductive function. Upon withdrawal of feeding for 45 days, these effects were reversible. Thus this extract manifests a definite contraceptive effect in female mice. Copyright © 2001 John Wiley & Sons, Ltd.
Cytostatic activity of Achillea ageratum L.
Authors: Gómez M. A. , García M. D. , Sáenz M. T. 
Published: August 2002

AbstractThe cytostatic activity of a chloroform extract and two isolated compounds from Achillea ageratum L. (Asteraceae) was determined in vitro against Hep‐2 and McCoy cells. The chloroform extract exhibited a high degree of growth inhibition compared with the values obtained with the 6‐mercaptopurine (positive control) against both cultures. Stigmasterol and β‐sitosterol, isolated from the chloroform extract, showed a high degree of growth inhibition. Copyright © 2001 John Wiley & Sons, Ltd.
Neurophysiological Effects of an Extract of Eschscholzia californica Cham. (Papaveraceae)
Authors: Rolland A. , Fleurentin J. , Lanhers M. C. , Misslin R. , Mortier F. 
Published: August 2002

AbstractAn aqueous alcohol extract of Eschscholzia californica (Ec) has been evaluated for benzodiazepine, neuroleptic, antidepressant, antihistaminic and analgesic properties, in order to complete the study of the sedative and anxiolytic effects previously demonstrated.The plant extract did not protect mice against the convulsant effects of pentylenetetrazol, and did not cause muscle relaxant effects but appeared to possess an affinity for the benzodiazepine receptor: thus, flumazenil, an antagonist of these receptors, suppressed the sedative and anxiolytic effects of the extract. The Ec extract induced peripheral analgesic effects in mice but did not possess antidepressant, neuroleptic or antihistaminic effects.
Ab initio modeling of competitive drug–drug interactions: 5‐fluorouracil dimers in the gas phase and in solution
Authors: Alagona Giuliano , Ghio Caterina , Monti Susanna 
Published: August 2002

Abstract5‐Fluorouracil (FU) is a halogen derivative of the uracil nucleoside widely used for treatment of solid tumors and in combination drug regimens for cancer chemotherapy. In drug delivery by biodegradable poly(ester‐ether‐ester)s, drug–drug interactions are competitive with respect to the drug–copolymer ones. The potential energy and free energy of association for a variety of FU–FU dimers (either H‐bonded or stacked) were therefore studied in the gas phase to shed some light on their absolute and relative strength, because competition between these two kinds of interactions was recently proposed [McCarthy et al. Mol Phys 1997, 91, 513] and examined with a combination of methods [Hobza et al. J Phys Chem A 1998, 102, 6921] for uracil dimers. The effect of the computational level [Hartree–Fock/second order Møller–Plesset (HF/MP2) or B3LYP, including or not counterpoise corrections to the basis set superposition error] was examined as well as that of the use of polarization functions more diffuse than usual 6‐31G*(0.25) more diffuse than usual. The MP2 level is necessary to describe stacking interactions, because B3LYP is inadequate for them, giving results very similar to the HF ones. The 6‐31G*(0.25) basis set produces very favorable interaction energies, but it is prone to basis set superposition error (BSSE). The binding free energy is noticeably less favorable than the potential energy, due to the increase in vibrational entropy for the association process. There is a good linear relationship between Svib and the binding energy for the HF/6‐31G* optimized structures. Estimates of the incidence of thermal corrections at the MP2 level were carried out on the MP2/3‐21G and B3LYP/6‐31G* structures, where possible. The solvation properties in chloroform or in water of the dimers kept rigid at their in vacuo geometries were examined in the polarizable continuum model framework. © 2001 John Wiley & Sons, Inc. Int J Quant Chem 83: 128–142, 2001
Screening for disulfide‐rich peptides in biological sources by carboxyamidomethylation in combination with differential matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry
Authors: Neitz Susanne , Jürgens Michael , Kellmann Markus , Schulz‐Knappe Peter , Schrader Michael 
Published: August 2002

AbstractPeptides with biological functions often contain disulfide bridges connecting two cysteine residues. In an attempt to screen biological fluids for peptides containing cysteine residues, we have developed a sensitive and specific method to label cysteines selectively and detect the resulting molecular mass shift by differential mass spectrometry. First, reduction of disulfide bridges and carboxyamidomethylation of free thiols is adjusted to quantitatively achieve cysteine alkylation for complex peptide extracts. In a second step, matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOFMS) before and after chemical derivatization is performed, followed by differential analysis to determine shifted peaks; shifted peaks belong to cysteine‐containing peptides, other peaks remain unchanged. The number of cysteines can then be determined by the resulting molecular mass shift. Free, reduced cysteines are shifted by 57 u, two oxidized cysteines involved in disulfide bridges (cystine) result in a shift to higher mass per disulfide bridge of 116 u. Disulfide bridges connecting different amino acid chains like insulin break up during reduction. In this case, two peaks with lower molecular masses result from a single one in the unmodified sample. With this technique, we were able to identify cysteine‐containing peptides and short fragments of proteins present in human blood filtrate. Copyright © 2001 John Wiley & Sons, Ltd.
Random regular graphs of high degree
Authors: Krivelevich Michael , Sudakov Benny , Vu Van H. , Wormald Nicholas C. 
Published: August 2002

AbstractRandom d‐regular graphs have been well studied when d is fixed and the number of vertices goes to infinity. We obtain results on many of the properties of a random d‐regular graph when d=d(n) grows more quickly than
$\sqrt{n}$. These properties include connectivity, hamiltonicity, independent set size, chromatic number, choice number, and the size of the second eigenvalue, among others. ©2001 John Wiley & Sons, Inc. Random Struct. Alg., 18: 346–363, 2001.
Interface evolution and bond strength when diffusion bonding materials with stable oxide films
Authors: Shirzadi A. A. , Assadi H. , Wallach E. R. 
Published: August 2002

AbstractThe effects of stable surface oxides on the interface morphologies and strengths of aluminium diffusion bonds are reviewed. Previous approaches, proposed to overcome problems with surface oxides when joining aluminium alloys and composites, are described and compared for both solid‐state diffusion bonding and conventional transient liquid‐phase diffusion bonding. Non‐conventional joining methods, particularly the new method of temperature‐gradient transient liquid‐phase diffusion bonding and its capability of producing high‐strength bonds reliably, also are considered. Copyright © 2001 John Wiley & Sons, Ltd.
Interactions of CO2 and CO at fractional atmosphere pressures with iron and iron oxide surfaces: one possible mechanism for surface contamination?
Authors: Miller D. J. , Biesinger M. C. , McIntyre N. S. 
Published: August 2002

AbstractThe interactions of carbon dioxide and carbon monoxide at moderately high pressures with clean iron surfaces have been studied using x‐ray photoelectron spectroscopy (XPS) and static time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS). Clean iron surfaces were analysed after exposure to CO2 or CO gas having pressures of 10–104 Pa at 25 °C. Exposure to either gas results first in a thin surface film of FeO. In addition, this oxide is completely or partially covered with a carbonaceous layer. The thickness of the carbon layer is influenced by the type of gas used and its pressure. The ToF‐SIMS studies using isotopically labelled 13CO2 under the same reaction conditions show that the labelled carbon is not enriched on the surface and therefore no direct reaction occurs between the labelled carbon and the surface. It is proposed that the influence of either gas on the carbonaceous layer formed may be indirect: these gases may alter the equilibrium partial pressures of other adsorbates on the walls of the vacuum chamber. Copyright © 2002 John Wiley & Sons, Ltd.
Responding to daily event questionnaires: the influence of the order of hassle and uplift scales
Authors: Maybery Darryl , Maybery Murray , Bresnan Renay , Croft Belinda , Graham Renae , Macaulay Jacinta , McQualter Sarah , Mitchell Elizabeth , Sherwell Kristy , Szakacs Emily 
Published: August 2002

AbstractTwo studies demonstrated differences in hassle and uplift ratings of daily events as a function of questionnaire order and format. In the first study, 123 undergraduates rated 143 events as both sources of hassles and sources of uplifts. The order of completion of hassle and uplift ratings had a substantial impact on uplift ratings, but only a minor impact on hassle ratings. Events were rated less uplifting when these ratings followed rather than preceded hassle ratings. The second study replicated this asymmetric order effect for hassle and uplift ratings when events were restricted to the 53‐item Delongis scale and when a middle‐aged sample was used (n = 104). Furthermore, prior hassle ratings were shown to suppress uplift ratings not only when the two sets of ratings were separated, but also when the typical combined format of the Delongis scale was used. In this combined format, events are listed in a central column and one set of ratings (e.g. hassles) is completed on the left, the other set (e.g. uplifts) on the right. An additional result was that uplift ratings were higher for the combined format compared to the separated format. Results are discussed with reference to a possible effect of hassle recall/evaluation on negative mood, which may then impact on uplift recall/evaluation. The findings highlight the potentially differential impact of negative and positive events on individuals and provide a clear direction for the ordering of scales (i.e. positive before negative) in questionnaire packages. Copyright © 2002 John Wiley & Sons, Ltd.
Creating transforming leadership for organizational change: the CogniScope System approach
Authors: Magliocca Larry A. , Christakis Alexander N. 
Published: August 2002

AbstractTo prepare for post‐industrial leadership in the twenty‐first century, we must transcend the circular journey of leadership studies of the twentieth century which is rooted in the industrial paradigm of organizations. The post‐industrial era of knowledge workers requires a group‐based, interactive framework of leadership. Based on the works of Burns (1978) and Rost (1991), the authors propose a definition of transforming leadership discovered through their systems design work. Three principles of transforming leadership are identified through the application of the CogniScope System. From 200 applications of the CogniScope System in various organizations, the phenomenon of transforming leadership has emerged as an important possibility. Observations from multiple applications of the CogniScope System have led to the codification of three principles that fit the context, content, and process of systems design work. The three principles are illustrated through excerpts of a case study. Using the case study, the authors identify specific events or group products to validate the claim that transforming leadership did occur. The authors identify a need for research by other emancipatory systems thinking methodologies to further our understanding of transforming leadership. The authors speculate on the emergence of transforming leaders/managers in new organizational structures that will support transforming leadership. Copyright © 2001 John Wiley & Sons, Ltd.
Towards unifying science: Applying concepts across disciplinary boundaries
Authors: Bailey Kenneth D. 
Published: August 2002

AbstractUnified science is one goal of systems science, but can only be achieved through a standardized, unified terminology. The practice of transporting concepts to other disciplines is widespread, but often lacks coherent planning, and thus fails to achieve terminological unification. The purpose of this paper is to explore ways that such unified terminology can be developed. Past trends in concept exportation are reviewed for a number of disciplines, showing that concept degradation is common. Four possible outcomes of concept exportation are presented. Next, strategies for terminological unification are identified. The last portion of the paper illustrates concept exportation by focusing on autopoiesis, cybernetics, and entropy. It is found that although neutral terms are often adopted, concept exportation meets resistance in both the origin and destination disciplines. Frequently prefixes are utilized to designate various applications of a term. In conclusion, an evaluation of the current state of terminological unification is offered, along with seven recommendations for the future. Copyright © 2001 John Wiley & Sons, Ltd.
Some structural health monitoring approaches for nonlinear hydraulic dampers
Authors: Wolfe Raymond W. , Masri Sami F. , Caffrey John 
Published: August 2002

AbstractViscous dampers are integral components in the implementation of structural control retrofit strategies on several new or retrofitted bridges throughout the world. Design engineers have realized the economic and engineering value of dissipating the large anticipated forces from wind and seismic loads. Owing to the significance of the role played by the dampers in the retrofit schemes, it is imperative that health monitoring strategies be investigated. Health monitoring procedures provide potential capabilities to continuously evaluate the integrity of components. The goals of the study reported herein were to conduct some analytical and experimental studies to evaluate a promising strategy for structural health monitoring of nonlinear viscous dampers. A nonparametric identification technique previously developed to handle a very broad class of nonlinear problems usually encountered in the structural dynamics field is used in conjunction with noise‐polluted synthetic data to assess the sensitivity of the proposed approach to detect slight changes in the characteristics of a nonlinear viscous damper under broadband excitation. By inspecting changes in the probability density function of the identified dominant system parameters, it is shown that the proposed structural health monitoring approach is capable of detecting small changes, even in the presence of a modest amount of noise pollution. Preliminary experimental results are also presented from a realistic laboratory model to illustrate the application of the monitoring scheme. Copyright © 2002 John Wiley & Sons, Ltd.
Activation of calpain may alter the postsynaptic density structure and modulate anchoring of NMDA receptors
Authors: Vinade Lucia , Petersen Jennifer D. , Do Khanh , Dosemeci Ayse , Reese Thomas S. 
Published: August 2002

AbstractElevation of calcium during sustained synaptic activity may lead to the activation of the postsynaptic calcium‐dependent protease calpain and thus could alter the integrity and localization of endogenous proteins. The distribution of anchoring proteins for neuroreceptors is an important determinant of the efficacy of neuronal transmission. Many of these anchoring proteins are concentrated within the postsynaptic density (PSD). In the present study, we examined the effects of calpain II on isolated PSDs using biochemical and electron microscopic techniques. Biochemical analysis reveals that PSD‐95, a clustering molecule which anchors NMDA receptors by interaction with their NR2 subunits, as well as the NR2 subunits themselves, are cleaved by calpain. On the other hand, under conditions where all the PSD‐95 protein is cleaved, actin and α‐actinin—a protein thought to anchor NMDA receptors to actin filaments—remain intact. For analysis by electron microscopy, PSDs were adsorbed on glass, immunogold‐labeled with an antibody to PSD‐95, slam frozen, freeze dried, and rotary shadowed. Electron micrographs of replicas indicate that PSDs are disc‐shaped and are composed of a lattice‐like structure which labels with PSD‐95 immunogold. After calpain treatment, PSDs adsorbed on glass become thinner overall and the lattice becomes fragmented. Altogether, these results suggest that calpain activity could produce changes in the organization of the PSD and, by cleaving PSD‐95 associated with the PSD lattice, could modify the anchoring of NMDA receptors. Synapse 40:302–309, 2001. © 2001 Wiley‐Liss, Inc.