bluuebunny/crossref_metadata_2025 huggingface dataset:
Role of sulphur in carburization, carbide formation and metal dusting of iron
Authors: Grabke H. J. , Moszynski D. , Müller‐Lorenz E. M. , Schneider A.
Published: October 2002

The kinetics and mechanisms of reactions on iron in CH4–H2 and CO–H2–H2O mixtures have been studied, also in the presence of H2S, to understand carburization, iron carbide formation, metal dusting and carbon deposition. Rate equations and mechanisms of the carburization in CH4–H2 and CO–H2–H2O have been elucidated. Both reactions are retarded by adsorbed sulphur, the rates becoming inversely proportional to the sulphur activity aS ∼ p(H2S)/p(H2) with increasing aS. At carbon activities aC > 1, cementite growth can be started in both gas mixtures on iron but the decomposition of this unstable carbide gives rise to a corrosion process called ‘metal dusting’, i.e. a disintegration of iron and steels to a dust of metal particles and graphitic carbon. This disintegration can be prevented by adsorbed sulphur, which hinders the nucleation of graphite. The stabilizing effect of sulphur on cementite and higher carbides such as Hägg carbide allows fundamental studies to be carried out on their thermodynamics, non‐stoichiometry and diffusional growth mechanisms, and the presence of sulphur will allow iron carbide production in a process of great present interest—the direct reduction of iron ores in carburizing gas mixtures. Kinetic studies in the system Fe–C–S are supplemented by AES and low‐energy electron diffraction investigations on the adsorption and segregation of sulphur on iron and cementite. Copyright © 2002 John Wiley & Sons, Ltd.
Formation of petroleum organic deposits on steel surfaces
Authors: Cosultchi A. , García‐Bórquez A. , Aguilar‐Hernandez J. , Yee‐Madeira H. , Reguera E. , Lara V. H. , Bosch P.
Published: October 2002

An adhered organic deposit, formed within the petroleum well on the steel surface of the tubing walls, was systematically characterized following a sequence of bulk and surface techniques. The results allowed the identification of the tubing wall and its internal surface structures. As a consequence of the contact with sulphur‐bearing compounds such as H2S and brine from petroleum, the pre‐oxidized steel surface was modified by non‐stoichiometric iron compound formation. These new iron phases favour adsorption and chemisorption of the petroleum polar compounds on the steel surface. Copyright © 2002 John Wiley & Sons, Ltd.
Application of argon r.f. plasma etching for the removal of oxidic scales on ULC steels
Authors: Martínez C. , Kyrsta S. , Cremer R. , Neuschütz D.
Published: October 2002

The effects of argon r.f. plasma etching processes on steel samples at discharge voltages substantially lower than 300 V were studied. The removal of not only the hydrocarbon contamination of the surface but also of the native oxidic scale was investigated by means of x‐ray photoelectron spectroscopy (XPS). Special attention was paid to the remaining structure of the surface after etching, using reflection high‐energy electron diffraction (RHEED) to determine the influence of plasma etching on the crystallographic structure. The removal of hydrocarbons was already effective at a power of 20 W. At a power of 60 W it was possible to remove the native oxidic scale in only a few minutes. In contrast to the amorphization observed after etching at high Ar+ energies, the crystalline structure of the outermost layers was not significantly influenced by the low‐energy ion etching. Copyright © 2002 John Wiley & Sons, Ltd.
Oxidation of the silicon carbide surface in Watts' plating bath
Authors: Socha R. P. , Laajalehto K. , Nowak P.
Published: October 2002

An important problem in metal–matrix composite production by electrochemical co‐deposition of SiC particles with nickel is the large variation of the SiC concentration in the composite. One of the possible reasons is the change of SiC surface properties due to its oxidation during contact with the plating bath. X‐ray photoelectron spectroscopy was applied to study the surface oxidation of the [0001] basal plane of α‐SiC crystals contacted with Watts' plating bath at 55°C. It was shown that the growth of silica at the surface is preceded by the formation of a silicon oxycarbide species (SiOxCy). The formation of graphite‐type carbon at the surface was also observed. The equivalent layer thickness of the main species at the oxidized surface was calculated. Copyright © 2002 John Wiley & Sons, Ltd.
Atomic‐order nitridation of SiO2 by nitrogen plasma
Authors: Seino Takuya , Matsuura Takashi , Murota Junichi
Published: October 2002

Atomic‐order nitridation of ∼30 Å thick SiO2 has been investigated by an electron‐cyclotron‐resonance nitrogen plasma. It is found that the number of nitrogen atoms in the nitrided SiO2 film increases with plasma exposure time and tends to saturate. In the initial nitridation of SiO2, the number of nitrogen atoms in the nitrided SiO2 film depends mainly on the number of incident ions, in dependence on the surface temperature. In the saturation region of the nitridation, it is found that the nitrogen concentration and the depth of the nitrided SiO2 increase with increasing ion energy as well as surface temperature. In the nitridation of SiO2, it is found that the nitrogen bonding structure in the nitrided SiO2 film is changed by ion irradiation with an energy of ∼12 eV and by the temperature increase of the irradiated surface. Copyright © 2002 John Wiley & Sons, Ltd.
Thermal nitridation of ultrathin SiO2 on Si by NH3
Authors: Jintsugawa Osamu , Sakuraba Masao , Matsuura Takashi , Murota Junichi
Published: October 2002

Thermal nitridation of a 30 Å thick SiO2 film on Si(100) was carried out at 750–850°C with NH3 pressures of 100–500 Pa using an ultraclean low‐pressure chemical vapour deposition system, and the depth profile of the nitrogen atom concentration in the SiO2 film was measured with atomic order resolution by repetitions of XPS measurement and etching with dilute HF solution dipping. It is suggested that nitrogen species are adsorbed at the outermost SiO2 surface by NH3 reaction, diffuse into the SiO2 film and then nitride the Si substrate surface at the SiO2/Si interface. With increasing nitridation time, the surface nitrogen concentration initially increased and saturated to 2–3(×1022) cm−3; the saturation time was dependent on the NH3 pressure. The interface nitrogen concentration increased with a delay period and saturated to ∼6.5 × 1014 cm−2; the time to increase of interface concentration was also dependent on the NH3 pressure. The diffusion characteristics of the nitrogen atoms in SiO2 were expressed by Fick's law and the temperature dependence of the diffusion coefficient was well determined as D = 2.2 × 10−8 exp(−2.2 eV/kT) (cm2 s−1). Finally, it is clarified that most of the nitrogen atoms can be localized to within a 10 Å thick surface region by choosing the nitridation conditions. Copyright © 2002 John Wiley & Sons, Ltd.
Angle‐resolved core‐level spectroscopy of Zr1Nb alloy oxidation by oxygen, water and hydrogen peroxide
Authors: Bastl Z. , Senkevich A. I. , Spirovová I. , Vrtílková V.
Published: October 2002

The initial oxidation of Zr1Nb alloy in oxygen, water and hydrogen peroxide at room temperature has been studied by angle‐resolved x‐ray photoelectron spectroscopy (ARXPS). The clean surface of alloy has been prepared either by scraping under ultrahigh (10−10 mbar) vacuum or by argon ion sputtering. The four well‐defined oxidation states of Zr were identified in the oxide films on Zr1Nb. The results of the ARXPS study were consistent with a layered structure of the oxide film, with zirconium dioxide in the outermost part of the film and suboxides in the inner region. The overall thickness of the incipient oxide layers ranged from 1.8 nm for the sputtered surface oxidized by oxygen, to 4.2 nm for the scraped surface oxidized in hydrogen peroxide. Mathematical analysis of the fitted Zr 3d spectra based on a layered structure model allowed us to estimate the thicknesses of individual suboxide layers. The population of suboxides as well as the binding energy of the Zr 3d electrons belonging to tetravalent zirconium were found to depend on the oxidizing agent and on the method used to clean the surface prior to oxidation. The amount of suboxides was much higher on the oxidized alloy surface cleaned by ion sputtering than on surfaces cleaned by scraping. The presence of zirconium hydride was observed in the spectra of Zr 3d electrons of the samples oxidized by water. The observed differences in binding energy of the Zr 3d component assigned to the Zr4+ oxidation state are interpreted by differences in the structure of the dioxide layer. Copyright © 2002 John Wiley & Sons, Ltd.
Charge trapping characterization in the thin oxide layer/non‐conductive substrate system
Authors: Liebault J. , Moya‐Siesse D. , Bernardini J. , Moya G.
Published: October 2002

The Trapping properties of a thin oxide layer deposited on a non‐conductive substrate are investigated. This study is based on the charge trapping behaviour of defects, depending on their nature and their distribution.

The injection of charges is made by means of the electron beam of a scanning electron microscope that exhibits a primary electron energy in the range 300–40 000 eV. Charge trapping characteristics are obtained by using the induced current method, which consists of measuring the evolution of the absorbed current induced by trapped charges in the metallic sample holder during the injection of charges. This method gives not only a quantitative determination of the amount of trapped charges but also the kinetics of charging.

In order to characterize the role of the interface (thin oxide /substrate), several tests are performed with various primary energies allowing the oxide, the interface and the substrate to be explored successively, because an increasing primary electron energy corresponds to an increasing penetration depth. As an example, MgO/glass and MgO/enamel systems are investigated. Comparison between these different charging kinetics leads to a better understanding of the effect of the interface on the trapping properties of such systems. Copyright © 2002 John Wiley & Sons, Ltd.
Investigation of thin films of mixed oxides for gas‐sensing applications
Authors: Kaciulis S. , Pandolfi L. , Viticoli S. , Sberveglieri G. , Zampiceni E. , Wlodarski W. , Galatsis K. , Li Y. X.
Published: October 2002

Recently, the thin films of some mixed metal oxides (Mo, Ti, Sn, W, etc.) have been indicated as very promising materials for gas‐sensing applications. Nevertheless, there is still a significant lack of experimental information on these compounds, where the surface properties can be defined not only by their chemical composition but also by the nanosized morphology of the films.

In this study we report the results of XPS investigations of Mo–Ti, Mo–Sn and Mo–W oxides. The films of mixed oxides with different composition ratios were prepared by sol–gel and magnetron sputtering techniques. The gas sensitivity of the films at different temperatures was studied by measuring the electrical response to typical gases.

Selected‐area XPS depth profiling of the samples was carried out by using cyclic Ar+ sputtering. The separation of different chemical species of the same element and quantitative analysis of experimental depth profiles enabled us to reveal completely the chemical composition of the films investigated. In such a way, the samples of mixed oxides, prepared by two different techniques and annealed at different temperatures (450–700°C), were characterized and compared. Copyright © 2002 John Wiley & Sons, Ltd.
XPS analysis of zinc hydroxystannate‐coated hydrated fillers
Authors: Mohai Miklós , Tóth András , Hornsby Peter R. , Cusack Paul A. , Cross Matthew , Marosi György
Published: October 2002

Aluminium hydroxide and magnesium hydroxide powder samples coated by zinc hydroxystannate (ZHS) to various extents have been studied by x‐ray photoelectron spectroscopy (XPS). For quantification of the XPS results a model was applied in which the substrate was covered by islands of ZHS, and this system was considered to be covered by a uniformly thin carbonaceous contamination overlayer. The surface coverage by ZHS and the thickness values of the carbonaceous and ZHS layers were determined for each sample by the recently developed XPS MultiQuant program. Relationships were established between the surface coverage, the layer thickness and the applied bulk concentration of ZHS. Low coating thickness values in the range of several nanometres have been obtained, which may account for the previously observed high flame retardant and smoke suppressant efficacy of zinc hydroxystannate‐coated fillers when applied in various polymeric formulations. Copyright © 2002 John Wiley & Sons, Ltd.
Reference curves based on non‐parametric quantile regression
Authors: Gannoun Ali , Girard Stéphane , Guinot Christiane , Saracco Jérôme
Published: October 2002

Reference curves which take time into account, such as those for age, are often required in medicine, but simple systematic and efficient statistical methods for constructing them are lacking. Classical methods are based on parametric fitting (polynomial curves). Semi‐parametric methods are also widely used especially in Europe. Here, we propose a new methodology for the estimation of reference intervals for data sets, based on non‐parametric estimation of conditional quantiles. The derived methods should be applicable to all clinical (or more generally biological) variables that are measured on a continuous quantitative scale. As an example, we analyse a data set collected to establish reference curves for biophysical properties of the skin of healthy French women. The results are compared to those obtained with Royston's polynomial parametric method and the semi‐parametric LMS approach. Copyright 2002 John Wiley & Sons, Ltd.
A Bayesian ordinal model for heterogeneity in a multi‐centre myocardial infarction clinical trial
Authors: Manda Samuel O. M.
Published: October 2002

A Bayesian methodology is developed to investigate the homogeneity of the treatment effects in a multi‐centre clinical trial with an ordinal response. A hierarchical model is formulated for the ordinal response, and the marginal posterior distributions of the covariates, overall treatment and the centre effects are calculated using the Gibbs sampler. The methodology is applied to data arising from a multi‐centre clinical trial of therapies for acute myocardial infarction. In this trial, the overall results show that the treatment is effective. However, there appears to be substantial differences in both the baseline risk and treatment effect across centres. Thus, the observed treatment effects may not be generalized to a broader patient population, and exploratory analyses to ascertain reasons for the treatment‐by‐centre interaction and its possible effect on the study conclusions would be useful. Copyright © 2002 John Wiley & Sons, Ltd.
Eliminating a framing bias by using simple instructions to ‘think harder’ and respondents with managerial experience: comment on ‘breaking the frame’
Authors: Wright George , Goodwin Paul
Published: October 2002

This paper shows that, in terms of experimental design and ecological validity, the recent study by Hodgkinson et al. (1999) does not ‘indicate that the framing bias is likely to be an important factor in strategic decision making.’ Nor does it suggest that ‘cognitive mapping provides an effective means of limiting the damage accruing from this bias.’ We show that the framing bias demonstrated b yHodgkinson et al. can be removed by a simpler ‘think‐harder’ manipulation with undergraduate respondents and, further, show that the bias is not present in the decisions of experienced respondents. We also demonstrate that, for experienced respondents, factors such as avoidance of risk and the creation of new strategies also characterize strategic decision making. Such components were not captured by Hodgkinson et al.'s experimental tasks. Copyright © 2002 John Wiley & Sons, Ltd.
Further reflections on the elimination of framing bias in strategic decision making
Authors: Hodgkinson Gerard P. , Maule A. John , Bown Nicola J. , Pearman Alan D. , Glaister Keith W.
Published: October 2002

Wright and Goodwin (2002) maintain that, in terms of experimental design and ecological validity, Hodgkinson et al. (1999) failed to demonstrate either that the framing bias is likely to be of salience in strategic decision making, or that causal cognitive mapping provides an effective means of limiting the damage accruing from this bias. In reply, we show that there is ample evidence to support both of our original claims. Moreover, using Wright and Goodwin's own data set, we demonstrate that our studies did in fact attain appropriate levels of ecological validity, and that their proposed alternative to causal cognitive mapping, a decision tree approach, is far from ‘simpler.’ Wright and Goodwin's approach not only fails to eliminate the framing bias—it leads to confusion. Copyright © 2002 John Wiley & Sons, Ltd.
Systemic administration of dizocilpine maleate (MK‐801) or l‐dopa reverses the increases in GAD65 and GAD67 mRNA expression in the globus pallidus in a rat hemiparkinsonian model
Authors: Bacci Jean‐Jacques , Salin Pascal , Kerkerian‐Le Goff Lydia
Published: October 2002

This study examined the consequences of systemic treatment with either L‐dopa or MK‐801 on the levels of mRNAs encoding the 65 and 67 kDa isoforms of glutamate decarboxylase (GAD65 and GAD67) in the striatum and globus pallidus (GP) of rats rendered hemiparkinsonian by intranigral 6‐hydroxydopamine injection. GADs mRNA levels were assessed by means of in situ hybridization histochemistry. In the striatum, dopamine denervation resulted in increased GAD67 mRNA levels at the rostral and caudal levels, whereas GAD65 showed selective increase at the caudal level. L‐dopa and MK‐801 treatments showed differential effects on the two GAD isoform levels in rats with 6‐hydroxydopamine lesion. The lesion‐induced increases in GAD67 transcripts were potentiated by L‐dopa but unaffected by MK‐801, whereas the increases in GAD65 were suppressed by MK‐801 but unaffected by L‐dopa. These data suggest a heterogeneity of glutamate‐dopamine interaction in the anteroposterior extent of the striatum and show that NMDA‐mediated mechanisms are involved in the 6‐hydroxydopamine lesion‐induced transcriptional changes in striatal GAD65 but not GAD67. In GP, the 6‐OHDA lesion elicited increases in both GAD65 and GAD67 mRNA levels. L‐dopa or MK‐801 treatment suppressed the lesion‐induced augmentations in the two GADs mRNA levels. These results indicate that dopamine denervation‐induced changes in the functional activity of GP neurons involve both dopamine and glutamate NMDA receptor‐mediated mechanisms. Comparison between the effects of L‐dopa and MK‐801 treatments on markers of the activity of striatal and pallidal GABA neurons further suggest that the impact of these treatments at the GP level do not depend solely on the striatopallidal input. Synapse 46:224–234, 2002. © 2002 Wiley‐Liss, Inc.
Validity of [123I]β‐CIT SPECT in detecting MDMA‐induced serotonergic neurotoxicity
Authors: Reneman Liesbeth , Booij Jan , Habraken Jan B.A. , De Bruin Kora , Hatzidimitriou George , Den Heeten Gerard J. , Ricaurte George A.
Published: October 2002

Recent [123I]β‐CIT single‐photon emission computed tomography (SPECT) studies revealed decreased serotonin transporters (SERT) density in the brain of humans with a history of MDMA (“Ecstasy”) use. However, [123I]β‐CIT SPECT has until now not been validated as a method for detecting such serotonergic lesions. Therefore, the present study was undertaken. Following baseline [123I]β‐CIT SPECT scans, a rhesus monkey was treated with MDMA (5 mg/kg, s.c. twice daily for 4 consecutive days). SPECT studies 4, 10, and 31 days after MDMA treatment revealed decreases in [123I]β‐CIT binding ratios in the SERT‐rich brain region studied (hypothalamic/midbrain region), with SERT density reduced by 39% in this brain region 31 days after treatment. Data obtained with SPECT studies correlated well with SERT density determined with autoradiography after sacrifice of the animal (−34%). In addition, ex vivo [123I]β‐CIT binding studies in rats 1 week after treatment with neurotoxic doses of MDMA (20 mg/kg s.c. twice daily for 4 consecutive days) revealed significant reductions in [123I]β‐CIT binding in SERT‐rich regions (including the hypothalamus) when compared to saline‐treated rats. The combined results of these studies indicate that SPECT imaging of SERT with [123I]β‐CIT can detect changes in SERT density secondary to MDMA‐induced neurotoxicity in the hypothalamic/midbrain region, and possibly other brain regions. Synapse 46:199–205, 2002. © 2002 Wiley‐Liss, Inc.
Knowledge management in collaborative product development
Authors: Fagerström Björn , Olsson Lars‐Erik
Published: October 2002

Today, an increasing amount of main suppliers are using sub‐suppliers to perform different tasks in the product development process. As a result, the knowledge needed to develop a new product is distributed among many actors. Knowledge management is a comprehensive term for providing the right piece of knowledge to the right people at the right time. This paper deals mainly with the question of how knowledge is managed in collaborative product development between main and subsuppliers (system level). The results are based on a case study with one main supplier and ten of their subsuppliers, in which the main suppler develops, assembles, and delivers a whole, complex product to the customer. The study shows that the subsuppliers' knowledge and experiences are not fully utilized in their relationship with the main supplier. Finally, some different ways of working are discussed in the paper's recommendation section, to improve the knowledge exchange between main and sub‐suppliers. © Wiley Periodicals, Inc. Syst Eng 5, 274–285, 2002
An in ovo chicken model to study the systemic and localized teratogenic effects of valproic acid
Authors: Whitsel Amy I. , Johnson Casey B. , Forehand Cynthia J.
Published: October 2002

Background

The antiepileptic valproic acid (VPA) is a teratogen whose embryopathic mechanism(s) remain uncertain. Elucidating potential cellular and molecular effects of VPA is complicated by systemic application paradigms. We developed an in ovo model to reproduce the teratogenic effects of VPA and a localized VPA application procedure to determine whether VPA can selectively effect abnormal development in one region of the embryo.

Methods

VPA was applied topically to chicken embryos in ovo at different embryonic stages. Embryos were later evaluated for gross and skeletal anomalies. Pax‐2 and Pax‐6 protein expression in the developing eye was also evaluated because VPA‐induced eye anomalies are similar to those seen by the disruption of Pax‐2 and Pax‐6. For localized application, a thin sheet of the synthetic polymer Elvax was impregnated with VPA. A small piece of the VPA‐impregnated polymer was applied directly to the presumptive wing bud region in Stage 10–17 embryos. Embryos were examined for gross and skeletal anomalies. Sham controls were employed for all experiments.

Results

Chicken embryos exposed to VPA in ovo demonstrated increased mortality, growth delay and anomalies similar to ones previously seen in humans: neural tube, cardiovascular, craniofacial, limb and skeletal. Pax‐2 and Pax‐6 protein expression was qualitatively diminished in the eye. Localized wing bud VPA exposure caused structural abnormalities in the developing wing in the absence of other anomalies in the embryos. These wing defects were similar to those observed after topical whole‐embryo VPA application.

Conclusions

These results indicate that at least one mechanism for the teratogenicity of VPA involves a direct effect on developing tissue. The nature of the abnormalities observed implies that this effect may be mediated by disruption of genes that regulate pattern formation. Teratology 66:153–163, 2002. © 2002 Wiley‐Liss, Inc.
Assessing student work from chatrooms and bulletin boards
Authors: Bauer John F.
Published: October 2002

Professors can establish rubrics for assessing participation in chatroom discussions and the content of student contributions in both chatrooms and bulletin boards.
A novel progressive modelling algorithm for 3D models
Authors: Yang Shu‐Kai , Chang Chin‐Chen , Duan Ding‐Zhou , Lin Ming‐Fen
Published: October 2002

This paper presents a novel progressive modelling algorithm for 3D models to generate progressive meshes. We propose a forest clustering simplification method to generate a progressive mesh of a model with the efficient and smooth transitions between meshes at different resolutions. Our approach can also integrate and balance the appearance attributes to preserve features of a model in the simplification process. We have applied our progressive modelling technique to several different kinds of input models and results show that our approach only generates efficient and smooth progressive meshes of a given model, but also preserves the features. The proposed method is very suitable for progressive transmission and real‐time rendering of 3D models in networked virtual environments. Copyright © 2002 John Wiley & Sons, Ltd.
EPMA and XRF characterization of therapeutic cave aerosol particles and their deposition in the respiratory system
Authors: Alföldy B. , Török Sz. , Balásházy I. , Hofmann W. , Winkler‐Heil R.
Published: October 2002

Cave therapy is an efficient therapeutic method to cure asthma, but the exact healing effect has not yet been clarified. This study was motivated by the basic assumption that aerosols may play a key role in cave therapy. Aerosol particles were collected in a therapeutic cave in Budapest, Hungary (Szemlöhegyi cave) at different locations arranged for the therapeutic treatment. Samples were further analysed by EPMA and XRF for chemical composition and morphology, determining the particle number distribution and classifying them according to their elemental composition. Three particle classes were determined based on major element concentrations: aluminosilicate, quartz and calcium carbonate. The combination of single‐particle EPMA and XRF resulted in relevant chemical information that could be used further for lung deposition modelling, namely the diameter and the number distribution to calculate the deposition probability, and the concentration of the element within a particle class necessary for the estimation of the deposited dose. The final results for the health effect study are the deposition efficiencies and deposition patterns of inhaled cave aerosols. The results of the stochastic deposition model showed that roughly 41% of the inhaled particles are deposited in the lung. From this amount, around 39% are deposited within airway generations 6–15, which is the most infected area in an asthmatic lung. The explanation of the healing effects might be based on the presented dose calculations. Copyright © 2002 John Wiley & Sons, Ltd.
Improvement in cholestasis associated with total parenteral nutrition after treatment with an antibody against tumour necrosis factor alpha
Authors: Forrest Ewan H. , Oien K. A. , Dickson S. , Galloway D. , Mills P. R.
Published: October 2002

Abstract:  Background: Many patients receiving long‐term total parenteral nutrition (TPN) develop liver disease; cholestasis is common and may be severe. Antitumour necrosis factor alpha (TNFα) antibodies have recently been used in order to treat Crohn's disease, but their effect on cholestasis in humans has not been previously described.

Case report: A 45‐year‐old woman had complicated Crohn's disease with multiple fistulae and only 1 m of residual small bowel. She had been receiving TPN for 2.5 years when she developed cholestasis which worsened despite adjustments to her TPN regimen. Infliximab, an anti‐TNFα antibody, was given with the aim of treating an enterocutaneous fistula, but it also produced a marked biochemical and histological improvement in the TPN‐related cholestasis.

Conclusions: Anti‐TNFα antibodies appeared in this case to improve TPN‐related cholestasis. This implies that TNFα may play an important role in the development of this condition.
Role of critical thiol groups on the matrix surface of the adenine nucleotide translocase in the mechanism of the mitochondrial permeability transition pore
Authors: McSTAY Gavin P. , CLARKE Samantha J. , HALESTRAP Andrew P.
Published: October 2002

Opening of the mitochondrial permeability transition pore (MPTP) is sensitized to [Ca2+] by oxidative stress (diamide) and phenylarsine oxide (PAO). We have proposed that both agents cross-link two thiol groups on the adenine nucleotide translocase (ANT) involved in ADP and cyclophilin-D (CyP-D) binding. Here, we demonstrate that blocking Cys160 with 80μM eosin 5-maleimide (EMA) or 500μM N-ethylmaleimide (NEM) greatly decreased ADP inhibition of the MPTP. The ability of diamide, but not PAO, to block ADP inhibition of the MPTP was antagonized by treatment of mitochondria with 50μM NEM to alkylate matrix glutathione. Binding of detergent-solubilized ANT to a PAO-affinity matrix was prevented by pre-treatment of mitochondria with diamide, EMA or PAO, but not NEM. EMA binding to the ANT in submitochondrial particles (SMPs) was prevented by pre-treatment of mitochondria with either PAO or diamide, implying that both agents modify Cys160. Diamide and PAO pre-treatments also inhibited binding of solubilized ANT to a glutathione S-transferase—CyP-D affinity column, both effects being blocked by 100μM EMA. Intermolecular cross-linking of adjacent ANT molecules via Cys57 by copper phenanthroline treatment of SMPs was abolished by pre-treatment of mitochondria with diamide and PAO, but not with EMA. Our data suggest that PAO and diamide cause intramolecular cross-linking between Cys160 and Cys257 directly (not antagonized by 50μM NEM) or using glutathione (antagonized by 50μM NEM) respectively. This cross-linking stabilizes the ‘c’ conformation of the ANT, reducing the reactivity of Cys57, while enhancing CyP-D binding to the ANT and antagonizing ADP binding. The two effects together greatly sensitize the MPTP to [Ca2+].
The functional consequences of mis-sense mutations affecting anintra-molecular salt bridge in arylsulphatase A
Authors: SCHESTAG Frank , YAGHOOTFAM Afshin , HABETHA Matthias , POEPPEL Peter , DIETZ Frank , KLEIN Roger A. , ZLOTOGORA Joel , GIESELMANN Volkmar
Published: October 2002

Metachromatic leukodystrophy is a lysosomal storage disorder caused by the deficiency of arylsulphatase A. We describe the functional consequences of three mis-sense mutations in the arylsulphatase A gene (Asp-335—Val, Arg-370—Trp and Arg-370—Gln), affecting an apparent intramolecular Asp-335 to Arg-370 salt bridge, and interpret the effects and clinical consequences on the basis of the three-dimensional structure of arylsulphatase A. Asp-335—Val and Arg-370—Trp substitutions each cause a complete loss of enzyme activity and are associated with the most severe form of the human disease, whereas the Arg-370—Gln-substituted enzyme retains some residual activity, being found in a patient suffering from the milder juvenile form of the disease. Detailed analysis reveals that formation of the apparent salt bridge depends critically on the presence of aspartic acid and arginine residues at positions 335 and 370, respectively. Substitution by various other amino acids, including glutamic acid and lysine, affects enzyme function severely. Biosynthesis and immunoprecipitation studies indicate that the Asp-335—Val substitution affects folding of arylsulphatase A more severely than either the Arg-370—Trp or Arg-370—Gln substitutions. In vitro mutagenesis data show that clinical severity correlates with the space occupied by residue 370. The combination with structural data suggests that the bulky tryptophan residue broadens the cleft held together by the apparent salt bridge, whereas the smaller glutamine residue still allows the cleft to close, yielding a less severely affected enzyme. The position of residue 370 in the three-dimensional structure of the enzyme provides a plausible explanation for the differing severities in loss of enzyme function caused by the mutations and thus the clinical phenotype.
Letter legibility and chart equivalence
Authors: McMonnies Charles W. , Ho Arthur
Published: October 2002

Introduction: We tested the appropriateness of the assumption that charts, which only vary in having different sequences of five letters per line, chosen from the same 10 letter set, can be regarded as equivalent for the purpose of making valid comparisons of visual acuity.

Method: Visual acuity findings from samples of 400 patients, for each of two nominally equivalent Bailey–Lovie charts, have been used to determine the relative legibility of individual letters and lines, using the percentage incorrect method of analysis.

Results: The chance of error for the hardest letter is approximately 13 times greater than for the easiest letter on each chart. Significant between‐chart differences in error rates for the hardest letters (‘F’ and ‘H’) were found. Some letters that have adjacent ranks on the legibility scale were found to have significantly different legibility. Significant differences in difficulty can occur for the same nominal line on apparently equivalent charts because of chance combinations of easier or harder letters in that line. Uneven line‐to‐line scale intervals have been confirmed for the charts examined, by showing corresponding differences in the distributions of lines of threshold acuity.

Conclusions: The use of varying examination distances may be inappropriate for Bailey–Lovie (or similar) charts that depart from their nominal interval scaling. When different versions of these charts are assumed to be equivalent, the discrepancy between repeated measurements may be significantly increased. There is the possibility of increasing measurement precision using charts having different sequences of the same 10 letters in each line to achieve equal scaling of line intervals. Equivalent charts can be validly constructed using different sequences of the same 10 letters in each line.
The prevalence of ocular defects and the provision of eye care in adults with learning disabilities living in the community
Authors: Woodhouse J. Margaret , Griffiths Christine , Gedling Alison
Published: October 2002

Most people with learning disabilities now live in the community rather than in institutions, and community services need to be targeted appropriately. Vision screening was carried out in community Day Care Centres for adults with learning disabilities. One hundred and fifty four subjects took part, and screening was successful in 148 subjects, using retinoscopy and standard acuity tests, including preferential looking.

The previously reported high prevalence of refractive errors, strabismus and pathological defects amongst people with learning disabilities was confirmed. Over 60% of subjects had below‐normal distance acuity, which in many cases was exacerbated by uncorrected refractive errors. In all, 41% of subjects could have benefited from distance spectacles, and 56% from spectacles for near tasks. The lack of adequate spectacles was particularly high amongst adults with more severe learning disabilities.

The study highlights the current lack of adequate eye care for people with learning disabilities, and demonstrates that eye examinations are possible for the majority of individuals. There is a need for greater awareness amongst families/carers and amongst optometrists to address this important issue.
Intra‐observer repeatability and inter‐observer agreement of the Smith method of measuring the anterior chamber depth
Authors: Osuobeni E. P. , Oduwaiye K. A. , Ogbuehi K. C.
Published: October 2002

The Smith (1979) method provides a means of estimating the anterior chamber depth without additional attachments to the slit lamp [Smith, R. J. H. (1979). A new method of estimating the depth of the anterior chamber. Br. J. Ophthalmol. 63, 215–220]. In this study, the 95% intra‐observer limits of repeatability and the 95% inter‐observer limits of agreement of this method have been determined. The intra‐observer limits of repeatability were determined by plotting the difference vs the mean of the estimated anterior chamber depth obtained in two different sessions by each of two examiners, while the inter‐observer limits of agreement are represented by a plot of the difference vs the mean estimated anterior chamber depth between the two examiners. For one examiner, the 95% intra‐observer limits of repeatability was −0.36 to 0.58 mm, while for the other examiner the 95% intra‐observer limits of repeatability was −0.25 to 0.37 mm. The 95% inter‐observer limits of agreement were −0.31 to 0.23 mm and −0.41 to 0.25 mm for the first and second sessions respectively. The intra‐observer limits of repeatability are comparable with those reported for A‐scan ultrasonographic measures of the anterior chamber depth. These results imply that the Smith method can be used with a high degree of repeatability and agreement to clinically monitor longitudinal changes in anterior chamber depth.
Palpable Thyroid and Parathyroid Nodules in Asymptomatic Cats
Authors: Norsworthy GD , Adams VJ , McElhaney MR , Milios JA
Published: October 2002

Client-owned cats underwent surgery to remove palpable cervical masses in cats with normal total T4 values and no clinical signs of hyperthyroidism, renal disease, or hyperparathyroidism. Non-functional thyroid and parathyroid adenomas were found and identified by histopathological examination. The significance of these findings is discussed in relation to palpating a goiterous mass in an asymptomatic cat.
Effect of sex and menstrual cycle phase on cytochrome P450 2C19 activity with omeprazole used as a biomarker
Authors: Kim Myong‐Jin , Bertino Joseph S. , Gaedigk Andrea , Zhang Yanhua , Sellers Edward M. , Nafziger Anne N.
Published: October 2002

Background

Literature addressing the effect of sex on cytochrome P450 (CYP) 2C19 activity is conflicting. The exogenous female sex steroid hormones used in oral contraceptives are believed to significantly inhibit CYP2C19 activity. However, the effect of variations in endogenous sex steroid concentrations throughout the menstrual cycle has not been investigated.

Objective

The objective of this study was to determine the effects of sex and menstrual cycle phase on CYP2C19 activity by using omeprazole.

Methods

White subjects with body weights between 45 and 66 kg received a single oral dose of 30 mg omeprazole. Those with weights of 67 to 90 kg received a dose of 40 mg. Twelve female subjects were phenotyped during the midfollicular and midluteal phases of the menstrual cycle for 3 complete cycles. Twelve male subjects were phenotyped every 14 days for 12 weeks. The 2‐hour postdose plasma concentration ratio of omeprazole to 5′‐hydroxyomeprazole was used as a measure of CYP2C19 activity. All subjects were genotyped for CYP2C19*2 and *3 alleles.

Results

Twelve women and 8 men were extensive metabolizers (EMs) with a CYP2C19*1/*1 genotype, whereas 4 male subjects were heterozygous (CYP2C19*1/*2). Median metabolic ratios during the midfollicular and midluteal visits were 0.845 and 0.930, respectively (P = .7). Sex had no effect on CYP2C19 activity in CYP2C19*1/*1 EMs (0.875 for men versus 1.070 for women, P = .140). The median metabolic ratios of all individuals with 2C19*1/*1 and *1/*2 genotypes were 0.94 and 3.75, respectively.

Conclusion

There is no sex difference in CYP2C19 activity in healthy white CYP2C19*1/*1 EMs with the omeprazole ratios. A gene‐dose effect was observed. In addition, variations in endogenous sex steroid concentrations throughout the menstrual cycle did not influence CYP2C19 activity.

Clinical Pharmacology & Therapeutics (2002) 72, 192–199; doi: 10.1067/mcp.2002.126174
Professional Innovations: Lifting Up Lives
Authors: Polick Therese J.
Published: October 2002

Professional Progress Notes reports innovations, ideas, and insights rele vant to the advancement of psychi atric nursing. Readers are encour aged to contribute their observations about front line issues, new approaches to care, and other related matters for inclusion in this regular feature.
Theoretical Antecedents to HIV Risk Perception
Authors: Brown Emma J. , Outlaw Freida H. , Simpson Edith M.
Published: October 2002

BACKGROUND: HIV risk perceptions have been unreliable in predicting behavioral change, suggesting that significantfactors which may contribute to HIV risk perception remain unknown.

OBJECTIVE: The purpose of this research was to describe HIV risk perceptions of two discordant samples and theorize about possible antecedents to their HIV risk perception.

STUDY DESIGN: The multiethnic samples consist of female college students (n = 286) and female HIV seronegative injecting drug users (n = 101). Secondary analysis of two data sets was conductedfor this comparative descriptive study.

RESULTS: Approximately 90% of college students and 60.4% of injecting drug users appraised their HIV risk as nil or small Injecting drug users were 3.1 times more likely than college students to perceive some risk of HIV infection and 28.8 times more likely to perceive a large or great risk.

CONCLUSION: Both samples minimized their HIV risk. HIV risk perception appears to be based on cognitive antecedents in addition to risky HIV-related sexual and drug-use behavior. It is theorized that both samples used the cognitive coping strategies of denial; distancing, and downward comparison to minimize their HIV risk perception.
Becoming Responsible Teens: Promoting the Health of Adolescents in Foster Care
Authors: McGuinness Teena M. , Mason Marian , Tolbert Grace , DeFontaine Cheryl
Published: October 2002

BACKGROUND: As a result of traumatic early histories, female adolescents in foster care are at great risk for contracting human immunodeficiency virus (HIV) and other sexually transmitted diseases.

OBJECTIVE: The purpose of this study was to evaluate the effectiveness of the Becoming a Responsible Teen (BART) curriculum on adolescents’ condom awareness and HIV risk knowledge. BART is an 8-week group intervention that combines education and behavior skills training with content on topics such as sexual assertion, refusal, problem solving, and risk recognition.

DESIGN: Adolescents living in residential foster care participated in the BART intervention. The study used a pretest/posttest design with one group.

FINDINGS: Preintervention and postintervention measures of outcomes of condom awareness and HIV risk knowledge improved significantly after the BART group intervention.

CONCLUSION: Adolescent females in foster care have experienced multiple early adversities and are a high-risk group for sexually transmitted diseases. BART increased the adolescents knowledge related to condom use and HIV risk and encouraged participants to spread the word to other adolescents.
Biofeedback Applications for Psychiatric Nursing
Authors: Patrick Graham J.
Published: October 2002

Americans increasingly are becoming disillusioned with traditional medical treatment and are seeking relief in complementary or alternative medicine (CAM) treatments for chronic physical or mental health problems. Biofeedback is a CAM approach that has important implications for holistic psychiatric nursing practice. This article covers the basics of clinical biofeedback and its potential applications for clients with psychiatric mental health issues. Information is provided about the availability of training, supervision, and certification in this expanding field.
Correlation of Simultaneous Differential Gene Expression in the Blood and Heart with Known Mechanisms of Adriamycin-Induced Cardiomyopathy in the Rat
Authors: Roger Brown H. , Hong Ni  , Benavides Gina , Yoon Lawrence , Hyder Karim , Giridhar Jaisri , Gardner Guy , Tyler Ronald D. , Morgan Kevin T.
Published: October 2002

As the genomes of mammalian species become sequenced and gene functions are ascribed, the use of differential gene expression (DGE) to evaluate organ function will become common in the experimental evaluation of new drug therapies. The ability to translate this technology into useful information for human exposures depends on tissue sampling that is impractical or generally not possible in man. The possibility that the DGE of nucleated cells, reticulocytes, or platelets in blood may present the necessary link with target organ toxicity provides an opportunity to correlate preclinical with clinical outcomes. Adriamycin is highly effective alone and more frequently in combination with other chemotherapeutic agents in the treatment of a variety of susceptible malignancies. Adriamycin-induced cardiomyopathy was examined as an endpoint to measure the utility of DGE on whole blood as a predictor of cardiac toxicity. Statistically significant gene changes were observed between relevant blood and cardiac gene profiles that corroborated the accepted mechanisms of toxicity (oxidative stress, effects on carnitine transport, DNA intercalation). There were, however, clear indications that other target organs (bone marrow and intestinal tract) were affected. The divergent expression of some genes between the blood and the heart on day 7 may also indicate the timing and mechanism of development of the cardiomyopathy and confirm current therapeutic approaches for its prevention. The data demonstrate that whole blood gene expression particularly in relation to oxidative stress, in conjunction with standard hematology and clinical chemistry, may be useful in monitoring and predicting cardiac damage secondary to adriamycin administration. Appendices A & B, referenced in this paper, are not printed in this issue of Toxicologic Pathology. They are available as downloadable text files at http://taylorandfrancis .metapress .com/openurl .asp?genre = journal&issn = 0192-6233. To access them, click on the issue link for 30(4), then select this article. A download option appears at the bottom of this abstract. In order to access the full article online, you must either have an individual subscription or a member subscription accessed through www .toxpath .org.
Skeletal Myopathy in Transgenic Mice Carrying Human Prototype c-Ha-ras Gene
Authors: Tsuchiya Takayuki , Kobayashi Kiyoshi , Sakairi Tetsuya , Goto Kazuhiro , Okada Miyoko , Sano Fumiko , Sugimoto Jiro , Morohashi Tetsuo , Usui Toshimi , Mutai Mamoru
Published: October 2002

Skeletal myopathy was found in almost all-transgenic mice carrying the human prototype c-Ha- ras gene (rasH2 mouse). Microscopically, variation of the muscle fiber size, centrally placed nuclei, regenerating fibers, and interstitial fibrosis were evident; hyalinization and necrosis were sometimes observed in the skeletal muscle ( femoralis and pectoralis) of the rasH2 mice. Inflammatory changes in the skeletal muscle or abnormality of adjacent peripheral nerve were not observed. The features were essentially similar to those of muscular dystrophy. Although the severity was relatively mild compared to 34-week-old rasH2 mice, the skeletal myopathy was also observed in younger male (10 weeks of age) rasH2 mice. In nontransgenic littermates, skeletal myopathy was not observed. The mRNA of human c-Ha- ras product was detected in femoral muscle from the rasH2 mice by RT-PCR. In conclusion, these data suggest that skeletal myopathy is occurring in almost all rasH2 mice. Integration of c-Ha- ras gene is thought to be crucial to pathogenesis of skeletal myopathy in the rasH2 mice. Further characterization of the muscular lesion and its pathogenesis are needed to explore the possibility of rasH2 mouse becoming a new model for muscular dystrophy.