bluuebunny/crossref_metadata_2025 huggingface dataset:
Theoretical study of the hydrogen chloride trihydrate
Authors: Struniewicz Cezary , Milet Anne , Sadlej Joanna , Moszynski Robert
Published: October 2002

Structural, energetic, and spectroscopic properties of the hydrogen chloride trihydrate (H2O)3HCl have been calculated by ab initio and density functional methods. The stationary points on the potential energy surface and the harmonic frequencies were obtained with the density functional theory, the second‐order Møller–Plesset theory, and the self‐consistent reaction field theory, while the corresponding interaction energies and binding energies were computed using the coupled‐cluster method restricted to single, double, and noniterative triple excitations. The origins of the bonding have been characterized by symmetry‐adapted perturbation theory of pair and three‐body interactions. The global minimum on the potential energy surface of the cluster corresponds to a cyclic structure with the water and hydrogen chloride molecules connected by hydrogen bonds. Another minimum, corresponding to an ionic form of the trihydrate, (H2O)2H3O+Cl−, has a binding energy only ≈2 kcal/mol higher than the global minimum, but it is separated by a large barrier. The pathway connecting the two minima has been found, and the structure of the corresponding transition state has been determined. The geometry of the ionic minimum agrees well with the crystal structure of the hydrogen chloride trihydrate from single‐crystal X‐ray diffraction studies. Also, the computed harmonic frequencies and their theoretical assignment are in agreement with the experimental data recorded in the gas phase in argon matrices and in the crystalline phase. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002
On the nature of the ground state of Cr(V) defects in YVO4: An ab initio model potential embedded‐cluster study
Authors: Pascual José Luis , Barandiarán Zoila , Seijo Luis
Published: October 2002

In this article we present the results of ab initio model potential (AIMP) embedded cluster calculations of the electronic structure of (CrO4)3− in the lattice of YVO4, in order to study the factors which determine the relative energy position of the two lowest lying electronic states of the Cr(V) ion as a dopant in this host lattice: 2A1 and 2B1. Electron paramagnetic resonance (EPR) and optical spectroscopy studies have reported these two states to be in reversed order from what should be expected following crystal field theory (CFT) considerations, taking into account the elongated distortion of the (VO4)3− cluster characteristic of the YVO4 lattice. The relative order predicted by CFT (2B1<2A1) is found when self‐consistent field (SCF) (CrO4)3− cluster calculations are done in vacuo. When AIMP embedded cluster calculations are performed using large multiconfigurational expansions for the 2A1 and 2B1 wavefunctions, the 2A1 state is found to be the ground state, in agreement with experimental evidence; the energy difference with respect to the 2B1 state is calculated to be 1650 cm−1. We have analyzed the results produced using different embeddings and different wavefunction expansions and we have reached the conclusion that embedding effects [both direct and indirect, through the local distortion produced by the Cr(V) impurity] and covalency (beyond SCF molecular orbital formation) are responsible for the energy reversal. Our results do not support previous interpretations of the energy reversal in terms of unusually strong interactions between the Cr(V) impurity and the two Y3+ cations in the second coordination sphere of the Cr(V). © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002
Constant denominator perturbative schemes and the partitioning technique
Authors: Surján Péter R. , Szabados Ágnes
Published: October 2002

With the aid of Löwdin's partitioning theory, an infinite series for the eigenvalue of the Schrödinger equation is derived which does not contain energy differences in denominators. The resulting formulae are compared to those of constant denominator methods, such as perturbation theory within the Unsøld approximation and the connected moment expansion (CMX). The Unsøld formulae are easily obtained from partitioning theory by a suitable choice of the zero order Hamiltonian. Optimizing the value of the energy denominator using the first order wave function in a size‐consistent way, the third order Unsøld correction vanishes, and the corresponding energy correction formula of the CMX is recovered at the second order. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002
Electric quadrupole and hexadecapole moments for X2CCX2, X = H, F, Cl, Br, and I*
Authors: Karamanis Panaghiotis , Maroulis George
Published: October 2002

We have calculated electric quadrupole and hexadecapole moments for ethene, tetrafluoroethene, tetrachloroethene, tetrabromoethene, and tetraiodoethene. A large basis set of [9s6p5d2f/5s4p2d] size is thought to provide reference near‐Hartree–Fock results for the electric multipole moments of ethene: Θxx=1.34 and \documentclass{article}\pagestyle{empty}\begin{document}$\Theta_{zz}=1.53\ ea_{0}^{2}$\end{document} for the quadrupole Φxxxx=−17.38, Φyyyy=20.29, and \documentclass{article}\pagestyle{empty}\begin{document}$\Phi_{zzzz}=-17.04\ ea_{0}^{4}$\end{document} for the hexadecapole moment (with z as the CC axis and the molecule on the xz plane). The electron correlation correction to the above values is estimated from coupled cluster calculations as Θxx=−0.12 and \documentclass{article}\pagestyle{empty}\begin{document}$\Theta_{zz}=-0.34\ ea_{0}^{2}$\end{document} for the quadrupole and Φxxxx=1.26, Φyyyy=−1.30, and \documentclass{article}\pagestyle{empty}\begin{document}$\Phi_{zzzz}=1.80\ ea_{0}^{4}$\end{document} for the hexadecapole moment. For the halogenated ethenes we have obtained the following quadrupole moment values from second‐order Mø ller–Plesset perturbation theory calculations: Θxx=−1.14 (C2F4), 1.94 (C2Cl4), 3.61 (C2Br4), 6.84 (C2I4) and Θzz=−1.04 (C2F4), −0.41 (C2Cl4), −0.15 (C2Br4), −0.87 (C2I4) \documentclass{article}\pagestyle{empty}\begin{document}$ea_{0}^{2}$\end{document}. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002
Ab initio quantum mechanical characterization of platinum, palladium, and nickel complexes of L‐ascorbic acid
Authors: Mora M. A. , Raya A. , Mora‐Ramirez M. A.
Published: October 2002

Electronic and structural properties of diamine–M ascorbate complexes {M(asc) (N–N)} where M is nickel, palladium, or platinum are studied with the use of ab initio molecular orbital methods at different levels of theory. The properties calculated for the platinum complex are compared with the experimental and theoretical values obtained previously and the agreement between them is shown to be good. Total overlap population values show that the ascorbate acts as a chelating ligand where coordination occurs through one carbon and one oxygen atom. We also present a detailed description of the bonding in order to characterize the intramolecular interactions in the M complexes. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002
Software algorithm for automatic interpretation of mass spectra of glycerolipids
Authors: Kurvinen J.‐P. , Aaltonen J. , Kuksis A. , Kallio H.
Published: October 2002

A new software algorithm for automatic interpretation of mass spectra of glycerolipids has been developed. The algorithm utilizes a user‐specified list of parameters needed to process the spectra. The compounds in mass spectra are identified according to range of measured m/z values, after which the spectra are automatically corrected by the content of naturally occurring isotopes and ion intensities of identified compounds by response correction factors. Automatic processing of the spectra was shown to be accurate and reliable by testing with numerous spectra of glycerophospholipids obtained by liquid chromatography/electrospray ionization mass spectrometry and by comparing the results with manual interpretation of the spectra. If quantitative analysis using internal standards is performed, all the identified compounds in the sample are quantified automatically. A dilution factor may be defined for each sample and is applied to correct the alterations in sample concentration during sample preparation. Processing of several replicate spectra simultaneously produces mean results with standard deviations. The software may also be used to subtract the results of two analyses and to calculate the mean result of replicate subtractions. The algorithm was shown to save time and labor in repetitive processing of mass spectra of similar type. It may be applied to processing of spectra obtained by various mass spectrometric methods. Copyright © 2002 John Wiley & Sons, Ltd.
Hydrophilic interaction liquid chromatography/electrospray mass spectrometry determination of acyclovir in pregnant rat plasma and tissues
Authors: Brown Stacy D. , White Catherine A. , Bartlett Michael G.
Published: October 2002

Reversed‐phase chromatography is the most common means of separation for small drug molecules. However, polar drugs may suffer from poor retention and peak shape in reversed‐phase high‐performance liquid chromatography (RP‐HPLC). Hydrophilic interaction liquid chromatography (HILIC) provides a viable alternative to RP‐HPLC and is an excellent way to separate polar compounds. This paper describes a HILIC/ESI‐MS/MS assay for the determination of acyclovir from rat plasma, amniotic fluid, placental tissue, and fetal tissue. The isocratic separation utilizes an underivatized silica column with an acetonitrile/formate buffer mobile phase (80:20). The method is validated over a range of 50 ng/mL to 50 µg/mL with % error and % relative standard deviation of <15% over 3 days. All samples are prepared by acetonitrile protein precipitation, which yields high recovery (>84% for acyclovir). This assay can be applied to the pharmacokinetic study of the placental transfer of acyclovir. Copyright © 2002 John Wiley & Sons, Ltd.
Sodium‐tolerant matrix for matrix‐assisted laser desorption/ionization mass spectrometry and post‐source decay of oligonucleotides
Authors: Lavanant Hélène , Lange Catherine
Published: October 2002

A mixture of 2′,4′,6′‐trihydroxyacetophenone in acetonitrile and aqueous triammonium citrate solution in a 1:1 molar proportion (0.2 M concentration) was found to be a good matrix for the detection of synthetic oligodeoxynucleotide samples. A high proportion of volatile solvent as well as the high salt content ensure fast co‐crystallization of the matrix, co‐matrix and analyte molecules. Matrix‐assisted laser desorption/ionization (MALDI) mass spectra obtained in negative ion reflectron mode from samples prepared with this protocol show deprotonated molecules [M − H]−, rather than sodium adducts, as the most abundant ions even when up to 50 mM of sodium chloride is present in the sample. The matrix is shown to be effective for low mass modified single nucleotides as well as for longer oligodeoxynucleotides (up to 18mer). Post‐source decay (PSD) mass spectra can also be obtained by increasing the laser fluence. Simple sequence information such as the identity and localization of a deleted base or the 5′/3′ orientation can then easily be obtained. The calibration method and mass accuracy required are discussed depending on the type of information required. Copyright © 2002 John Wiley & Sons, Ltd.
“Trampeg”: An MPEG‐2 real‐time software transcoder for low‐bit‐rate transmission
Authors: Akutsu Takashi , Kimata Hideaki , Shimizu Atsushi , Yashima Yoshiyuki , Kobayashi Naoki
Published: October 2002

In the audiovisual handling of content coded by MPEG‐2 transmitted over various kinds of networks such as the Internet or LAN, transformation of coding bit rates or transcoding is necessary. The simplest transcoding method is that of decoding MPEG‐2 completely and then reencoding it at a lower bit rate. However, real‐time processing of this method on a commonly used PC is difficult since the level of operations or the computational complexity for coding is high. However, if using the before‐transformation coding information decreases the computational complexity, real‐time transformation (transcoding) by software becomes possible. In this study, the Trampeg software transcoder (transcoder for MPEG‐2) capable of real‐time transcoding MPEG‐2 with high quality has been developed. The applications, design guidelines, and processing algorithms of Trampeg are presented in this paper. The results of evaluation for operation of the system over a real PC have verified that an MPEG‐2 system stream input via a network can be transcoded in real time and the transcoded low‐rate stream can be transmitted directly to a streaming server. © 2002 Wiley Periodicals, Inc. Syst Comp Jpn, 33(12): 77–86, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.10062
A machinery control system using mobile agents
Authors: Wada Hidehiko , Sakuraba Yuichi , Negishi Masako , Yamakawa Toshiharu
Published: October 2002

Flexibility will be one of the key features in future manufacturing systems because the environments that surround manufacturing systems are rapidly changing from day to day. To satisfy this requirement, we propose an autonomous decentralized system using agents. In manufacturing systems using agents, the basic concept should be based on a target product and on work having some information moving around in the system. To realize this concept, we introduce several agents called product agent or machine agent. To verify our proposed concept and architecture, we developed a prototype system. This system was for the Shape Deposition Manufacturing Laboratory of the Robotics Institute at Carnegie Mellon University. © 2002 Wiley Periodicals, Inc. Syst Comp Jpn, 33(12): 47–57, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.10122
X‐ray photoelectron spectroscopy as a method to control the formation of metal–carbon tubules
Authors: Shabanova I. N. , Makarova L. G. , Kodolov V. I. , Kuznetsov A. P.
Published: October 2002

In the given paper the use of x‐ray photoelectron spectroscopy as a means to control the formation of metal–carbon tubules by low‐energy synthesis from multi‐ring hydrocarbons in active media is discussed. The dependence of C–C bond formation on the content of the initial components in mixtures prepared from fine powders of anthracene and metal chloride (Me = Mn, Co, Ni) was studied by means of x‐ray photoelectron spectra. Based on the results of x‐ray photoelectron spectroscopy, the assumption about the mechanisms of formation and growth of tubules was made, confirmed by the results obtained by transmission electron microscopy. Copyright © 2002 John Wiley & Sons, Ltd.
Atomic‐scale investigation of the localized corrosion of passivated nickel surfaces
Authors: Maurice V. , Klein L. H. , Marcus P.
Published: October 2002

In situ scanning tunnelling microscopy measurements of the localized corrosion of Ni(111) surfaces passivated in a chloride‐free sulphuric acid solution and subsequently exposed to chloride (0.05 M) are reported. The results support the deterministic role of the structure of the passivated surface on the dissolution in the passive state, independent of the addition of chloride in the electrolyte. The atomic lattice of the passive film formed in the absence of chloride is unmodified after the addition of chloride. At the investigated potential of +0.85 VSHE (0.05 V below the stable pitting potential), the dissolution proceeds by a two‐dimensional step flow process that is dependent on the step orientation, the steps oriented along the closed‐packed directions dissolving much less rapidly than the steps oriented along no well‐defined directions of the oxide lattice. The dissolution rate of the oxide lattice is ∼6 NiO ‘molecules’ s−1, independent of the presence of chloride. The comparison with the rate of dissolution that can be estimated from the measured electrochemical current density in the passive state suggests that the dissolution of the oxide lattice of the passive film is not the major anodic reaction in the passive state. Copyright © 2002 John Wiley & Sons, Ltd.
Chrome‐free pretreatment for aluminium composites
Authors: Hamdy Abdel Salam , Beccaria Anna Maria
Published: October 2002

The effect of manganese pretreatment on the corrosion behaviour of AA6061 T6–10% Al2O3 metal–matrix composite was investigated in aerated aqueous 3.5% NaCl solution using electrochemical impedance spectroscopy (EIS). The corrosion inhibition characteristics were studied for two series of manganese‐pretreated specimens after 30 days of immersion in NaCl solution at different pH, pretreatment times and different surface preparation prior to manganese pretreatment. Polarization tests were used to investigate the perfect passivity domain after 60 days of immersion in NaCl. Results showed that the specimens treated in KMnO4 + NaCl, in pure KMnO4 solution for a long time (1–7 days) at neutral pH and in pure KMnO4 solution at pH 8 for a short time (<1 h) suffered from pitting, crevice or general corrosion. Conversely, the specimens treated in pure KMnO4 solution for 3 h at pH 8 or at neutral pH did not show any sign of corrosion. X‐ray photoelectron spectroscopy revealed the presence of a high percentage of Al2O3 in addition to Mn oxide as a compact surface film. A promising corrosion resistance was obtained by sealing in a silicate solution for 2 min after treatment in pure KMnO4 solution. Microscopic examinations showed that silicon plays an important role in improving the protective power of the passive film by repairing the pitting results from chloride ion attack. Copyright © 2002 John Wiley & Sons, Ltd.
Elastic electron backscattering from silicon surfaces: effect of surface roughness
Authors: Zemek J. , Jiricek P. , Jablonski A. , Lesiak B.
Published: October 2002

The inelastic mean free paths (IMFPs) in Si have been investigated frequently using experimental and theoretical approaches. At present, the only experimental method providing the IMFPs is elastic peak electron spectroscopy (EPES). However, in previous studies, a scatter between published data in Si was observed that originated from the statistical and systematic error of the EPES method. In the present work, systematic study has been carried out on the influence of surface roughness on the electron IMFPs determined by the EPES method using a Cu standard. The Si surfaces (polished and ground) characterized by surface roughnesses of 5.5 and 760.0 nm have been studied under electron emission angles of 35° and 70° with respect to the surface normal. It has been shown that these differences in surface roughness do not affect the measured IMFPs. Slight deviations in the IMFPs measured at two geometries were observed for low electron energies, indicating an increase of IMFPs at electron emission close to glancing angle due to the lower densities at the surface with respect to the bulk and the smaller elastic cross‐sections used in the EPES calculations. Copyright © 2002 John Wiley & Sons, Ltd.
AES characterization of oxide grains formed on ductile cast irons in exhaust environments
Authors: Tholence F. , Norell M.
Published: October 2002

Cast alloys (SiMo and Ni‐resist) were oxidized at 850°C for 50 h in dry air and synthetic diesel exhaust gases. High‐resolution AES analysis and SEM studies on sections of the inner oxides showed that, for both alloys, thicker silicon‐containing oxides layers were formed at metal/oxide interfaces in diesel than in air. For SiMo, fayalite appeared to precipitate within this layer in diesel gases, thus lowering its protectiveness. Further out, silica may reprecipitate. Where the austenitic Ni‐resist failed to maintain a protective interfacial oxide, a highly irregular oxide/metal interface led to metallic Ni‐rich particles becoming trapped in the oxide. Copyright © 2002 John Wiley & Sons, Ltd.
The Cochrane Collaboration – how is it progressing?
Authors: Laupacis Andreas
Published: October 2002

During the last seven years, the Cochrane Collaboration has rapidly developed into an important international organization, producing high quality systematic reviews of randomized trials. Challenges, which it will likely meet, include maintaining the quality of the reviews, ensuring that reviews are done of the most common therapies for important diseases, securing stable funding, and making the format of the reviews more accessible for the average clinician. Copyright © 2002 John Wiley & Sons, Ltd.
Industry perspectives on ICH guidelines
Authors: Rockhold Frank W.
Published: October 2002

In 1990 the International Conference on Harmonization (ICH) effort was begun with the intent of standardizing the drug registration and approval process. The need to rationalize and harmonize regulation was driven by concerns over rising costs of health care, escalation of the cost of research and development and the need to meet the public expectation that there should be a minimum delay in making safe and efficacious new treatments available to patients in need. Since most regulatory agencies have limited resources to interact with sponsor companies, standardized guidelines would help expedite communications with companies at the programme design stage. The ICH is a joint initiative involving both regulators and industry as partners in scientific and technical discussions of the testing procedures which are required to ensure the safety and efficacy of medicines. While all regions of the world have some input to the process, the primary development of the guidelines is derived from industry and regulatory representatives from Europe, Japan and the United States. Much progress has been made in the ten years since the initiation of the ICH, but the implementation and maintenance of the guidelines are in the early stages for most if not all of the published guidelines. If the guidelines do not gain a solid foothold early on, then drift between the regions in use of the guidelines will defeat the goals of the ICH. While the ICH covers the entire drug development process, this paper will review the guidelines that pertain most closely to clinical trials and their use in the drug registration process. Some of the guidelines have been approved and some are still in the development stage. Copyright © 2002 John Wiley & Sons, Ltd.
Role of brain α1B‐adrenoceptors in modafinil‐induced behavioral activity
Authors: Stone Eric A. , Cotecchia Susanna , Lin Yan , Quartermain David
Published: October 2002

These studies show that either central pharmacological blockade or genetic ablation of α1B‐adrenoceptors markedly attenuates the behavioral activation caused by modafinil, implicating these receptors in the drug's action. Synapse 46:269–270, 2002. © 2002 Wiley‐Liss, Inc.
Gamma‐vinyl GABA, an irreversible inhibitor of GABA transaminase, alters the acquisition and expression of cocaine‐induced sensitization in male rats
Authors: Gardner Eliot L. , Schiffer Wynne K. , Horan Bryan A. , Highfield David , Dewey Stephen L. , Brodie Jonathan D. , Ashby Charles R.
Published: October 2002

We examined the effect of (±)‐gamma‐vinyl GABA (GVG, Vigabatrin), an irreversible inhibitor of the enzyme GABA transaminase, on the acquisition and expression of cocaine‐induced sensitization in albino male Sprague‐Dawley rats. Animals received a single injection of 1 ml/kg i.p. of 0.9% saline or 15 mg/kg i.p. of (−)‐cocaine and locomotor activity was assessed using automated locomotor cages and stereotyped behaviors were scored using a 4‐point rating scale (Day 1). Subsequently, animals were given 15 mg/kg i.p. of cocaine every 48 h in their home cage for 1 week (Days 3, 5, and 7) and then given no treatment for 1 week. A challenge injection of 15 mg/kg i.p. of cocaine, but not vehicle, produced a significant increase in locomotor activity and stereotyped behaviors on Day 15 compared to animals that received cocaine on Day 1. Administration of 75 mg/kg i.p. of GVG 2.5 h before the cocaine injections did not significantly alter the acquisition of cocaine‐induced locomotor sensitization. However, 150 mg/kg i.p. of GVG significantly attenuated the acquisition of cocaine‐induced locomotor sensitization. Administration of 150 mg/kg i.p. of GVG 2.5 h before the cocaine challenge injection on Day 15 significantly attenuated the expression of cocaine‐induced locomotor sensitization. Acquisition and expression of cocaine‐induced sensitization of stereotypy was also significantly attenuated by 150 mg/kg i.p. of GVG. Since sensitization may be one of the factors involved in relapse to drug use, the present results, in combination with previous findings that GVG blocks the rewarding and incentive motivating effects of cocaine, suggest that GVG might prove useful in the treatment of cocaine addiction. Synapse 46:240–250, 2002. © 2002 Wiley‐Liss, Inc.
Widespread but regionally specific effects of experimenter‐ versus self‐administered morphine on dendritic spines in the nucleus accumbens, hippocampus, and neocortex of adult rats
Authors: Robinson Terry E. , Gorny Grazyna , Savage Virginia R. , Kolb Bryan
Published: October 2002

We studied the effects of self‐administered (SA) vs. experimenter‐administered (EA) morphine on dendritic spines in the hippocampal formation (CA1 and dentate), nucleus accumbens shell (NAcc‐s), sensory cortex (Par1 and Oc1), medial frontal cortex (Cg3), and orbital frontal cortex (AID) of rats. Animals in the SA group self‐administered morphine in 2‐h sessions (0.5 mg/kg/infusion, i.v.) for an average of 22 sessions and animals in the EA group were given daily i.v. injections of doses that approximated the total session dose for matched rats in Group SA (average cumulative dose/session of 7.7 mg/kg). Control rats were given daily i.v. infusions of saline. One month after the last treatment the brains were processed for Golgi‐Cox staining. In most brain regions (Cg3, Oc1, NAcc‐s) morphine decreased the density of dendritic spines, regardless of mode of administration (although to a significantly greater extent in Group SA). However, only SA morphine decreased spine density in the hippocampal formation and only EA morphine decreased spine density in Par1. Interestingly, in the orbital frontal cortex morphine significantly increased spine density in both Groups SA and EA, although to a much greater extent in Group SA. We conclude: 1) Morphine has persistent (at least 1 month) effects on the density of dendritic spines in many brain regions, and on many different types of cells (medium spiny neurons, pyramidal cells, and granule cells); 2) The effect of morphine on spine density (and presumably synaptic organization) varies as a function of both brain region and mode of drug administration; and 3) The ability of morphine to remodel synaptic inputs in a regionally specific manner may account for the many different long‐term sequelae associated with opioid use. Synapse 46:271–279, 2002. © 2002 Wiley‐Liss, Inc.
Assessing and managing risks to information assurance: A methodological approach
Authors: Lamm Gregory A. , Haimes Yacov Y.
Published: October 2002

Recent events such as the September 11th attack, the Yahoo! denial‐of‐service attack, the I Love You virus, and the Code Red worm have sparked a dramatic interest in assuring the future security of information infrastructures. Information systems are increasingly interconnected, interdependent, and complex. Information assurance (IA) attempts to answer critical questions of trust and credibility associated with our digital environment. It presents myriad considerations and decisions that transcend many dimensions: technological advancement, legal, political, economic, social, cultural, institutional, organizational, and educational. Despite the millions of dollars spent on firewalls, encryption technologies, and intrusion detection software, information infrastructure vulnerabilities and disruptive incidents continue. These trends have a significant impact on military operations now and for the next decades. This paper identifies and develops a methodological framework for assessing and managing IA risks. The methodology is based on the systems engineering design process as well as on the guiding principles of risk assessment and management. It builds on hierarchical holographic modeling (HHM) and risk filtering, ranking, and management (RFRM). HHM identifies a plethora of risk scenarios and sources of risk that are innate in current complex information systems. The flexibility of the HHM philosophy permits limitless representations of systems perspectives, constrained only by the knowledge, creativity, and imagination of the analyst and the appropriateness of the modeling efforts. RFRM is an eight‐phase process that filters the hundreds of risk scenarios down to a manageable few (10–20), and ranks them. The risk management phase then identifies the acceptable policy options and analyzes the tradeoffs among them by using quantifiable risk management tools. This process analyzes the wealth of statistical data on losses due to system failures, to intrusions, or to vulnerabilities of information assurance. © 2002 Wiley Periodicals, Inc. Syst Eng 5: 286–314, 2002
Dynamic processes of conceptual change: Analysis of constructing mental models of chemical equilibrium
Authors: Chiu Mei‐Hung , Chou Chin‐Cheng , Liu Chia‐Ju
Published: October 2002

The purpose of this study was to investigate students' mental models of chemical equilibrium using dynamic science assessments. Research in chemical education has shown that students at various levels have misconceptions about chemical equilibrium. According to Chi's theory of conceptual change, the concept of chemical equilibrium has constraint‐based features (e.g., random, simultaneous, uniform activities) that might prevent students from deeply understanding the nature of the concept of chemical equilibrium. In this study, we examined how students learned and constructed their mental models of chemical equilibrium in a cognitive apprenticeship context. Thirty 10th‐grade students participated in the study: 10 in a control group and 20 in a treatment group. Both groups were presented with a series of hands‐on chemical experiments. The students in the treatment group were instructed based on the main features of cognitive apprenticeship (CA), such as coaching, modeling, scaffolding, articulation, reflection, and exploration. However, the students in the control group (non‐CA group) learned from the tutor without explicit CA support. The results revealed that the CA group significantly outperformed the non‐CA group. The students in the CA group were capable of constructing the mental models of chemical equilibrium—including dynamic, random activities of molecules and interactions between molecules in the microworld—whereas the students in the non‐CA group failed to construct similar correct mental models of chemical equilibrium. The study focuses on the process of constructing mental models, on dynamic changes, and on the actions of students (such as self‐monitoring/self‐correction) who are learning the concept of chemical equilibrium. Also, we discuss the implications for science education. © 2002 Wiley Periodicals, Inc. J Res Sci Teach 39: 688–712, 2002
8‐Iso‐PGF2α administration generates dysmorphogenesis and increased lipid peroxidation in rat embryos in vitro
Authors: Wentzel Parri , Eriksson Ulf J.
Published: October 2002

Background

Diabetic pregnancy displays increased incidence of congenital malformations and elevated levels of lipid peroxides in the offspring. The aim of the present work was to study if exogenous administration of one lipid peroxide, the isoprostane 8‐iso‐PGF2α, is teratogenic per se in rat embryos in vitro, and if such teratological effects may be diminished by supplementation of an antioxidative agent, i.e., N‐acetylcysteine or superoxide dismutase, to the culture medium.

Methods

Day‐9 embryos were cultured in vitro for 48 hr and subjected to 8‐iso‐PGF2α with and without N‐acetylcysteine or superoxide dismutase.

Results

Addition of 2 μmol/l of the isoprostane 8‐iso‐PGF2α to the culture medium caused high malformation rate, decreased protein and DNA contents, decreased somite number and crown‐rump‐length as well as marked accumulation of the isoprostane in the embryonic tissues. Adding N‐acetylcysteine or superoxide dismutase to the culture medium with isoprostane normalized almost all morphological and biochemical parameters, including the elevated tissue concentration of 8‐iso‐PGF2α.

Conclusions

Results indicate that the isoprostane (8‐iso‐PGF2α) serves both as an oxidative stress indicator and a teratogenic agent. The findings support earlier studies of enhanced oxidative stress and increased malformation rate in embryos exposed to a diabetes‐like environment, and suggest prevention of dysmorphogenesis by administration of antioxidative agents. Teratology 2:164–168, 2002. © 2002 Wiley‐Liss, Inc.
Coupling toxicokinetics and pharmacodynamics for predicting survival of abalone (Haliotis diversicolor supertexta) exposed to waterborne zinc
Authors: Liao Chung‐Min , Chen Bo‐Ching , Lin Ming‐Chao , Chiu Hsiao‐Mei , Chou Yun‐Hua
Published: October 2002

We developed a mortality model, by coupling an acute toxicity model and a pharmacodynamic model, to predict survival of abalone (Haliotis diversicolor supertexta) exposed to waterborne zinc (Zn). We conducted a laboratory 14‐day exposure experiment to obtain biokinetic parameters of depuration rate constant (k2) and bioconcentration factor (BCF). A one‐compartment uptake–depuration model was used to fit the exposure data to estimate BCF and k2 values. The acute toxicity model was developed based on the receptor theory and was verified with LC50(t) data obtained from a 7‐day acute toxicity test. A highly significant correlation (r2 = 0.98) was found between predictions and LC50(t) data for the acute toxicity model, indicating a successful description of 7‐day LC50(t) data of Zn in abalone. The predicted time course of lethal body burden of Zn in abalone was compared with measured data, showing that the average percent error was 14.04 ± 3.02%. A refined pharmacodynamic model was expressed as the Hill equation, which in terms of waterborne Zn and LC50(t) data was used to fit observed mortality percentages to determine the Hill coefficient (r2 = 0.98). The proposed mortality model in terms of whole body burden and lethal body burden at site of action was then employed to predict the time‐varying mortality of abalone exposed to various Zn concentrations in pond water. Our results demonstrate that 96‐h LC50 and incipient LC50 for H. diversicolor supertexta exposed to Zn are 1.1 and 1.05 mg L−1, respectively. Our predictions also demonstrate that equilibrium lethal body burden at site of action is about 198 μg g−1, whereas the mortalities never reach 50% when H. diversicolor supertexta exposed to Zn is ⩽ 1 mg L−1. © 2002 Wiley Periodicals, Inc. Environ Toxicol 17: 478–486, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/tox.10082
Enhancement of TXRF intensity by using a reflector
Authors: Tsuji Kouichi , Wagatsuma Kazuaki
Published: October 2002

We investigated the possibility of enhancing the TXRF intensity by applying an Si reflector. This Si reflector was attached just above the Si sample carrier. The angle between the reflector and the sample carrier was changed by tilting the reflector. We attempted to focus the primary x‐rays on the analyzed area by multi‐reflection effects between the reflector and the sample carrier. The intensity of Au Lα emitted from a thin layer of Au deposited on an Si sample carrier, was measured as a function of the angle between two Si plates. The observed peaks were explained from simple calculations, suggesting that the reflection of primary x‐rays on both the reflector and the sample carrier results in a significant increases in x‐ray intensities. In addition, Ar Kα emitted from the air, was reduced substantially by applying the reflector. This indicates that a reflector is also useful for reducing the x‐ray background that originates from the air and the sample carrier. Copyright © 2002 John Wiley & Sons, Ltd.
A cell surface display system using novel GPI‐anchored proteins in Hansenula polymorpha
Authors: Kim So‐Young , Sohn Jung‐Hoon , Pyun Yu‐Ryang , Choi Eui‐Sung
Published: October 2002

A cell surface display system was developed in yeast Hansenula polymorpha.The four genes HpSED1, HpGAS1, HpTIP1and HpCWP1, encoding glycosylphosphatidyl‐inositol (GPI)‐anchored cell surface proteins from H. polymorpha, were cloned, characterized and evaluated for their efficacies as cell surface display motifs of reporter proteins. Sequence analysis of these genes revealed that each encodes a typical GPI‐anchored protein that is structurally similar to a counterpart gene in S. cerevisiae. The genes showed a high content of serine‐threonine (alanine) and harboured a putative secretion signal in the N‐terminus and the GPI‐attachment signal in the C‐terminus. The surface anchoring efficiency of these putative cell surface proteins was tested by fusion to the C‐terminal of carboxymethylcellulase (CMCase) from Bacillus subtilis. In all cases, high CMCase activities were detected in intact cell fraction, indicating anchoring of CMCase to the cell surface. HpCwp1p, HpGas1p and the 40 C‐terminal amino acids of HpTip1p from H. polymorphaexhibited a comparatively high CMCase surface anchoring efficiency. When these proteins were used as anchoring motifs for surface display of the glucose oxidase (GOD) from Aspergillus niger, most enzyme activity was detected at the cell surface. Fluorescence activated cell sorter (FACS) analysis of cells displaying GOD on the cell surface demonstrated that GOD was well exposed on the cell surface. HpCwp1p showed the highest anchoring efficiency among others. Copyright © 2002 John Wiley & Sons, Ltd.
Effect of TT virus co‐infection on interferon response in chronic hepatitis C patients
Authors: Kawanaka Miwa , Niiyama Gouichi , Mahmood Sabina , Ifukube Satoshi , Yoshida Nobuhiro , Onishi Hideki , Hanano Shinichi , Ito Toshio , Yamada Gotaro
Published: October 2002

Abstract:  Aim: TT virus (TTV) is a single stranded DNA virus found in serum of patients with post‐transfusion non‐A to ‐G hepatitis. TTV‐DNA has been investigated in sera of patients with various liver diseases. This study aimed at finding whether co‐infection with TTV in HCV patients, may influence the effect of interferon (IFN) in complete elimination of HCV, and analysed the correlation between HCV and TTV by semi‐quantification of both HCV RNAs and TTV DNA.

Methods: In 28 chronic hepatitis C (CH‐C) patients with TTV co‐infection, the presence of TTV DNA was checked in sera six months before and after the end of IFN therapy.

Result: Five out of 28 patients became negative for both HCV‐RNA and TTV‐DNA following IFN therapy. But 10 out of 28 patients persistently remained positive for both. Among the remaining 13 patients, 5 tested negative for HCV‐RNA but positive for TTV‐DNA. Post IFN therapy changes in serum alanine aminotransferase (ALT) levels did not appear to be influenced by the presence of TTV co‐infection. HCV‐RNA was found to be the most important predictor of IFN response in CH‐C patients with TTV co‐infection. TTV DNA level in sera had no correlation with IFN response. In addition, there was no relationship between HCV RNA and TTV DNA.

Conclusion: Based on these results, it can be concluded that the effectiveness of IFN in eliminating HCV does not seem to be influenced by co‐infection.
Growth inhibition by the muscarinic M3 acetylcholine receptor: evidence for p21Cip1/Waf1 involvement in G1 arrest
Authors: BURDON Drew , PATEL Rajnikant , CHALLISS R.A. John , BLANK Jonathan L.
Published: October 2002

We have assessed the growth response of Chinese-hamster ovary (CHO) cells to activation of recombinantly expressed G-protein-coupled muscarinic M2 or M3 acetylcholine receptors (AChRs). We show that activation of these receptors leads to divergent growth responses: M2 AChR activation causes an increase in DNA synthesis, whereas M3 AChR activation causes a dramatic decrease in DNA synthesis. We have characterized the M3 AChR-mediated growth inhibition and show that it involves a G1 phase cell-cycle arrest. Further analysis of this arrest indicates that it involves an increase in expression of the cyclin-dependent kinase (CDK) inhibitor, p21Cip1/Waf1 (where Cip1 is CDK-interacting protein 1 and Waf1 is wild-type p53-associated fragment 1), in response to M3 AChR activation. This increase in protein expression leads to an increase in p21Cip1/Waf1 association with CDK2, a decrease in CDK2 activity and an accumulation of hypophosphorylated retinoblastoma protein. The increased p21Cip1/Waf1 expression is due, at least in part, to an increase in p21Cip1/Waf1 mRNA, and receptor-mediated changes in phosphorylation of c-Jun provide a mechanism to account for this p21Cip1/Waf1 transcriptional regulation. Evaluation of the extracellular signal-regulated protein kinase and c-Jun N-terminal kinase activities has shown striking differences in the profiles of activation of these mitogen-activated protein kinases by the M2 and M3 AChRs, and their potential involvement in mediating growth arrest by the M3 AChR is discussed.
The role of phenylalanine-119 of the reverse transcriptase of mouse mammary tumour virus in DNA synthesis, ribose selection and drug resistance
Authors: ENTIN-MEER Michal , SEVILYA Ziv , HIZI Amnon
Published: October 2002

Phe-119 in the reverse transcriptase (RT) of mouse mammary tumour virus (MMTV) is homologous with Tyr-115 in HIV type 1 (HIV-1) RT and to Phe-155 in murine leukaemia virus (MLV) RT. By mutating these residues in HIV-1 and MLV RTs (which are strict DNA polymerases) the enzymes were shown to function also as RNA polymerases. Owing to the uniqueness of MMTV as a type B retrovirus, we have generated a Phe-119—Val mutant of MMTV RT to study the involvement of this residue in affecting the catalytic features of this RT. The data presented here show that the mutant MMTV RT can incorporate both deoxyribonucleosides and ribonucleosides while copying either RNA or DNA. In addition, this mutant RT shows resistance to nucleoside analogues and an enhanced fidelity of DNA synthesis; all relative to the wild-type enzyme. The Phe-119—Val mutant is also different from the wild-type enzyme in its preference for most template primers tested and in its ability to synthesize DNA under non-processive and processive conditions. Overall, it is likely that the aromatic side chain of Phe-119 is located at the dNTP-binding site of MMTV RT and thus might be part of a putative ‘steric gate’ that prevents the incorporation of nucleoside triphosphates. Since the only three-dimensional structures of RTs published so far are those of HIV-1 and MLV, it is likely that MMTV RT folds quite similarly to these RTs.
A novel enzyme activity involving the demethylation of specific partially methylated oligogalacturonides
Authors: WILLIAMS Martin A.K. , BENEN Jacques A.E.
Published: October 2002

Studies of the enzymic digestion of pectic substrates using different polygalacturonase (PG) preparations have revealed evidence for a previously unreported enzyme activity carried out by a contaminating enzyme in one of the preparations. This observed activity involves the demethylation of specific oligogalacturonides, namely 2-methyltrigalacturonic acid and 2,3-dimethyltetragalacturonic acid. However, no large-scale demethylation of highly methylated polymeric substrates is found, demonstrating that the enzyme responsible is not a conventional pectin methylesterase (PME). Furthermore, it has been shown that a commercial sample of fungal PME from Aspergillus niger demethylates all of the oligogalacturonides present as primary products of endo-PG digestion, in contrast with the activity observed here. On the basis of the known methyl ester distribution of the endo-PG-generated fragments and knowledge of which of these oligogalacturonides are demethylated, it is concluded that the observed activity can be explained by the existence of an exo-acting methylesterase that attacks the non-reducing end of the oligogalacturonide molecules.
Do borderline nuclear changes in gynaecological cytlogy constitute a reliable reporting category?
Authors: THE BORDERLINE NUCLEAR CHANGES NATIONAL SLIDE EXCHANGE STUDY
Published: October 2002

Fourteen laboratories participated in a national slide exchange study to investigate whether borderline nuclear changes (BNC) constitute a reliable reporting category. Slides were submitted by participating laboratories, having achieved a 100% intralaboratory consensus at the primary screener, checker, and medical levels. Sets of seven slides were examined in laboratories for 1 week, and exchanges were undertaken over a 6‐month period. Each laboratory was requested to submit three consensus opinions on each slide at the primary screener, checker, and medical levels.

Response patterns for submitted slides achieving a reporting category consensus at the 50 and 80% consensus levels indicated that negative, BNC, and mild dyskaryosis are distinct and comparable categories. Similarly, the two subcategories of BNC with or without human papillomavirus (HPV) are nearly as distinct as the overall BNC category.

The percentage of submitted slides achieving consensus at consensus levels between 50 and 80% produced variable findings with regard to the practical success of the main reporting categories. The negative category was reasonably successful, whereas mild dyskaryosis was consistently poor. Borderline nuclear changes were successful at the 50% consensus level but showed a rapid decline by the 65% consensus level. The reason(s) for this remains speculative but indicates a possible potential of BNC to work successfully with additional training and education.

Reporting practices were not consistent among the laboratories and differences were identified between medical and nonmedical staff. A high use of the BNC category was noted in slides that failed to achieve consensus. A national study assessing all grades of abnormalities would appear essential.
Maternal allergen immunization during pregnancy in a mouse model reduces adult allergy‐related antibody responses in the offspring
Authors: Melkild I. , Groeng E.‐C. , Leikvold R. B. , Granum B. , Løvik M.
Published: October 2002

Background The immune status and allergen exposure of the mother may influence the immune response in the offspring after birth. This relationship may be important both for allergen avoidance strategies and, alternatively, for allergy prophylaxis by allergen exposure of the mother.

Objective The aim of the present study was to investigate the effect of allergen immunization of the mother during pregnancy and postpartum, in relation to the allergy‐related immune response (IgE) and the non‐allergy‐related (IgG2a) response in the offspring.

Methods Pregnant NIH/OlaHsd females were immunized three times during pregnancy and one time postpartum with ovalbumin and the adjuvant Al(OH)3, and the offspring's ovalbumin‐specific IgE, IgG1 and IgG2a responses were measured after challenge with the same allergen as young adults. Ovalbumin‐specific IgE, IgG1 and IgG2a responses were also analysed in offspring of NIH/OlaHsd females immunized once at different times during pregnancy: about 3 days into pregnancy, mid‐pregnancy (10 days into pregnancy) and about 4 days before giving birth (17 days into pregnancy).

Results Allergen immunization of mother during pregnancy and postpartum significantly reduced the IgE response in the progenies, whereas the IgG2a response to the same allergen was increased. Allergen immunization of the mother 3 days into pregnancy resulted in a significantly lower IgE response in offspring compared with the response in offspring of non‐immunized mothers and in offspring of mothers immunized 17 days into pregnancy.

Conclusions Maternal allergen immunization might favour selection for an allergen‐specific Th1‐dependent antibody response in the offspring. Our results indicate that IgE suppression is stronger after maternal allergen exposure during early pregnancy than after exposure in late pregnancy.