bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of hypoxia and reoxygenation on cytokine‐induced production of proinflammatory mediators in articular cartilage
Authors: Cernanec Julie , Guilak Farshid , Weinberg J. Brice , Pisetsky David S. , Fermor Beverley
Published: August 2002

Objective

Articular cartilage is an avascular tissue that functions at a lower oxygen tension than do most tissues. With mobilization, arthritic joints may undergo cycles of hypoxia and reoxygenation. The goal of this study was to determine the effects of hypoxia and reoxygenation on cytokine‐induced nitric oxide (NO) and prostaglandin E2 (PGE2) production in articular cartilage.

Methods

Porcine cartilage explants were incubated at 37°C for 72 hours in either 1% O2 (hypoxia) or 20% O2 (normoxia) in media supplemented with interleukin‐1α (IL‐1α) or tumor necrosis factor α (TNFα), with or without the NO synthase 2 (NOS2) selective inhibitor 1400W. Culture media were then removed and replaced with freshly prepared media and incubated for a further 24 hours in normoxia.

Results

NO levels were significantly higher in explants supplemented with IL‐1α and TNFα compared with controls, in both hypoxia and normoxia. Compared with normoxia, hypoxia decreased IL‐1α– and TNFα‐induced NO production significantly. Reoxygenation of hypoxic explants resulted in sustained significant NO production in response to either cytokine. However, comparably high levels of NO production were not sustained in explants cultured continuously in normoxia. Although IL‐1α alone did not significantly increase PGE2 production, significant PGE2 superinduction occurred in cartilage stimulated with IL‐1α and the NOS2 inhibitor 1400W compared with stimulation with IL‐1α alone in hypoxia, but not in normoxia.

Conclusion

Oxygen tension significantly affects cytokine‐induced proinflammatory mediator production in articular cartilage. Furthermore, hypoxia alters NO mediation of PGE2 production. Hypoxia and reoxygenation can affect cytokine‐induced proinflammatory mediator production, suggesting that oxygen tension may influence inflammation associated with cartilage injury and disease.
Erythroblast iron metabolism and serum soluble transferrin receptor values in the anemia of rheumatoid arthritis
Authors: Fitzsimons Edward J. , Houston Tracey , Munro Robin , Sturrock Roger D. , Speekenbrink Anthony B. J. , Brock Jeremy H.
Published: August 2002

Objectives

We have investigated in vitro erythroblast iron metabolism in the anemia of rheumatoid arthritis (RA). We also have examined the results in relation to bone marrow iron status in an attempt to explain the reported difference between serum soluble transferrin receptor (sTfR) values in anemia of chronic disease (ACD) and iron deficiency anemia (IDA) in patients with RA.

Methods

Bone marrow was examined in 29 anemic patients with RA, 9 healthy volunteers, and 6 patients with simple IDA. High purity erythroblast fractions were prepared from these bone marrow samples. Erythroblast surface TfR expression and iron uptake was assessed in vitro using 125I‐transferrin (Tf) and 59Fe‐Tf, respectively. The efficiency of erythroblast surface TfR function for Tf‐iron uptake was determined by relating total iron uptake at 4 hours to surface TfR number. Serum sTfR values were measured for the RA anemia group, which was subdivided as RA‐ACD (marrow iron present) or RA‐IDA (marrow iron absent) on the basis of visible reticuloendothelial (RE) marrow iron stores.

Results

High purity (87 ± 5%) erythroblast fractions were obtained from 35 of the 44 marrow samples. Erythroblasts obtained from patients with simple IDA showed a significant increase in surface TfR expression (P = 0.0003) and Tf‐iron uptake (P = 0.001). RA anemia also led to a significant increase in erythroblast Tf‐iron uptake (P = 0.016). This increase was not associated with an increase in surface TfR expression (P = 0.5), but was seen to occur as a result of a significant increase in the efficiency of surface TfR for Tf‐iron uptake (P = 0.027). Within the RA anemia group, the increase in erythroblast Tf‐ iron uptake at 4 hours was more evident for RA‐IDA (3.96 ± 1.73 versus 1.66 ± 0.66; P = 0.03) than for RA‐ACD (2.69 ± 1.18 versus 1.66 ± 0.66; P = 0.057). This additional erythroblast response to absent RE iron stores led to a highly significant difference in serum sTfR values between RA‐IDA and RA‐ACD (40.2 ± 14.0 versus 23.9 ± 5.3 nmoles/liter; P = 0.001)

Conclusions

An increase in erythroblast surface TfR efficiency for Tf‐iron uptake compensates for the low plasma iron levels associated with anemia in RA and helps to maintain RA erythroblast iron uptake. With adequate RE iron stores, this increased efficiency limits intracellular iron deprivation and consequently reduces the need to increase surface TfR expression. As a result, serum sTfR levels in RA‐ACD remain within the normal range. RA erythroblasts, however, are still able to respond to any additional worsening of the iron supply caused by absent RE iron stores. This additional response causes the highly significant increase in serum sTfR values seen between RA‐IDA and RA‐ACD.
A survey in indexing and searching XML documents
Authors: Luk Robert W.P. , Leong H.V. , Dillon Tharam S. , Chan Alvin T.S. , Croft W. Bruce , Allan James
Published: August 2002

XML holds the promise to yield (1) a more precise search by providing additional information in the elements, (2) a better integrated search of documents from heterogeneous sources, (3) a powerful search paradigm using structural as well as content specifications, and (4) data and information exchange to share resources and to support cooperative search. We survey several indexing techniques for XML documents, grouping them into flat‐file, semistructured, and structured indexing paradigms. Searching techniques and supporting techniques for searching are reviewed, including full text search and multistage search. Because searching XML documents can be very flexible, various search result presentations are discussed, as well as database and information retrieval system integration and XML query languages. We also survey various retrieval models, examining how they would be used or extended for retrieving XML documents. To conclude the article, we discuss various open issues that XML poses with respect to information retrieval and database research.
On the shape of the mean residual lifetime function
Authors: Finkelstein M. S.
Published: August 2002

Some general properties of the mean residual life (MRL) function are studied. The analysis is based on the shape of the corresponding failure rate. The conditions under which the failure rate and the reciprocal to the MRL function have asymptotically equivalent behaviour as t→∞ are discussed. The simplest non‐monotone shapes of the functions under consideration (bathtub and upside down bathtub) are also considered. The MRL functions for mixtures of distributions are described via the corresponding conditional probability density functions. The direct proportional model of mixing is characterized and some asymptotic results on the shape of the mixture MRL are obtained. Some simple examples are given. Copyright © 2002 John Wiley & Sons, Ltd.
The proportion heuristic: problem set size as a basis for performance judgments
Authors: Silvera David H. , Josephs Robert A. , Giesler R. Brian
Published: August 2002

How do people evaluate their degree of mastery over a task? A series of four studies demonstrated that a potentially irrelevant cue can have a strong influence on such evaluations. In these studies, the total amount of work given to participants (the problem set size) influenced both (a) the amount of work participants completed before feeling that they had performed well and were adequately prepared for a related future task, and (b) participants' assessments of their performance and their feelings of preparedness for a related future task. These effects occurred even when a randomization procedure was used to emphasize the arbitrary nature of the problem set size. The effects vanished, however, when participants were given extra time to evaluate their progress after completing each problem. Copyright © 2001 John Wiley & Sons, Ltd.
Calculation of electric fields induced in the human knee by a coil applicator
Authors: Buechler D.N. , Christensen D.A. , Durney C.H. , Simon B.
Published: August 2002

Calculations are presented of the induced electric fields and current densities in the cartilage of the knee produced by a coil applicator developed for applying pulsed magnetic fields to osteoarthritic knees. This applicator produces a sawtooth‐like magnetic field waveform composed of a series of 260‐μs pulses with a peak to peak magnitude of approximately 0.12 mT in the cartilage region. The simulations were performed using a recently developed 3 dimensional finite difference frequency domain technique for solving Maxwell's equations with an equivalent circuit model. The tissue model was obtained from the anatomically segmented human body model of Gandhi. The temporal peak electric field magnitude was found to be −153 mV/m, averaged within the medial cartilage of the knee for the typical dB/dt excitation levels of this coil. The technique can be extended to analyze other excitation waveforms and applicator designs. Bioelectromagnetics 22:224–231, 2001. © 2001 Wiley‐Liss, Inc.
Haploid all the way: a new style of asexuality revealed in animals
Authors: Perrot Véronique
Published: August 2002

Weeks et al(1) recently reported that they had found a species of mites where the parthenogenetic females are haploid. They show that this is caused by intracellular bacteria that turn genetic haploid males into haploid females. I discuss these findings and attempt to place these observations in evolutionary context. BioEssays 24:114–118, 2002. © 2002 Wiley Periodicals, Inc.
Bacterial actins? An evolutionary perspective
Authors: Doolittle Russell F. , York Amanda L.
Published: August 2002

According to the conventional wisdom, the existence of a cytoskeleton in eukaryotes and its absence in prokaryotes constitute a fundamental divide between the two domains of life. An integral part of the dogma is that a cytoskeleton enabled an early eukaryote to feed upon prokaryotes, a consequence of which was the occasional endosymbiosis and the eventual evolution of organelles. Two recent papers1, 2 present compelling evidence that actin, one of the principal components of a cytoskeleton, has a homolog in Bacteria that behaves in many ways like eukaryotic actin. Sequence comparisons reveal that eukaryotic actin and the bacterialhomolog (mreB protein), unlike many other proteins common to eukaryotes and Bacteria, have very different and more highly extended evolutionary histories. BioEssays 24:293–296, 2002. ©2002 Wiley Periodicals, Inc.
Toward reconstitution of in vivo microtubule dynamics in vitro
Authors: Andersen Søren S. L. , Wittmann Torsten
Published: August 2002

The transition from interphase to mitosis is marked by a dramatic change in microtubule dynamics resulting in the reorganization of the microtubule network that culminates in mitotic spindle formation. While the molecular basis for this change in microtubule organization remains obscure, it is currently thought that a balance in the activity of microtubule stabilizing and destabilizing factors regulates how dynamic cellular microtubules are. By mixing the microtubule stabilizer XMAP215 and the microtubule destabilizer XKCM1, reconstitution of in vivo‐like microtubule dynamics has now been achieved in vitro.(1) BioEssays 24:305–307, 2002. ©2002 Wiley Periodicals, Inc.
Sound silencing: the Sir2 protein and cellular senescence
Authors: Defossez Pierre‐Antoine , Lin Su‐Ju , McNabb David S.
Published: August 2002

The model organism Saccharomyces cerevisiae is providing new insights into the molecular and cellular changes that are related to aging. The yeast protein Sir2p (Silent Information Regulator 2) is a histone deacetylase involved in transcriptional silencing and the control of genomic stability. Recent results have led to the identification of Sir2p as a crucial determinant of yeast life span. Dosage, intracellular localization, and activity of Sir2p all have important effects on yeast longevity. For instance, calorie restriction apparently increases yeast life span by increasing Sir2p activity. Since Sir2p‐related proteins have been identified in many prokaryotic and eukaryotic organisms, the fundamental principles derived from the studies in yeast may prove valuable in directing our future research toward an understanding of the mechanisms of aging in higher eukaryotes. BioEssays 23:327–332, 2001. © 2001 John Wiley & Sons, Inc.
Glial cell development in the Drosophila embryo
Authors: Jones Bradley W.
Published: August 2002

Glial cells play a central role in the development and function of complex nervous systems. Drosophila is an excellent model organism for the study of mechanisms underlying neural development, and recent attention has been focused on the differentiation and function of glial cells. We now have a nearly complete description of glial cell organization in the embryo, which enables a systematic genetic analysis of glial cell development. Most glia arise from neural stem cells that originate in the neurogenic ectoderm. The bifurcation of glial and neuronal fates is under the control of the glial promoting factor glial cells missing. Differentiation is propagated through the regulation of several transcription factors. Genes have been discovered affecting the terminal differentiation of glia, including the promotion glial–neuronal interactions and the formation of the blood–nerve barrier. Other roles of glia are being explored, including their requirement for axon guidance, neuronal survival, and signaling. BioEssays 23:877–887, 2001. © 2001 John Wiley & Sons, Inc.
Hindbrain patterning revisited: timing and effects of retinoic acid signalling
Authors: Begemann Gerrit , Meyer Axel
Published: August 2002

Retinoids play a critical role in patterning, segmentation, and neurogenesis of the posterior hindbrain and it has been proposed that they act as a posteriorising signal during hindbrain development. Until now, direct evidence that endogenous retinoid signalling acts through a gradient to specify cell fates along the anteroposterior axis has been missing. Two recent studies tested the requirement for retinoid signalling in the developing hindbrain through systematic application of a pan‐retinoic acid receptor antagonist.(1,2) They demonstrate a stage‐dependent requirement for increasing retinoid signalling activity along the hindbrain that proceeds from anterior to posterior. Together these findings challenge the concept of a stable gradient of retinoic acid across the hindbrain and warrant a re‐interpretation of the phenotypes obtained by genetic and nutritional disruption of retinoid signalling in the amniote embryo. BioEssays 23:981–986, 2001. © 2001 John Wiley & Sons, Inc.
A comparative study of bovine blood and milk neutrophil functions with luminol‐dependent chemiluminescence
Authors: Mehrzad Jalil , Dosogne Hilde , Vangroenweghe Frédéric , Burvenich Christian
Published: August 2002

In this study, a technique was developed for the chemiluminescence (CL) measurement of bovine milk polymorphonuclear leukocytes (PMN). In the first study, the effects of cell number and the concentration of phorbol‐12‐myristate‐13‐acetate (PMA), luminol, latex bead particles, dimethyl sulphoxide (DMSO) and gelatin on the luminol‐dependent cellular CL (LDCL) response were assessed with healthy cows in different stages of lactation. In the second study, the LDCL andin vitrobactericidal activity of blood and milk PMN towardsStaphylococcus aureuswas investigated. In general, the CL activity of blood PMN was consistently higher than that of milk PMN. We found that (a) the optimal cell density in blood and milk cells for maximal LDCL response ranged from 1.5 × 106to 5 × 106cells/mL; (b) the optimal concentrations of PMA, latex beads and luminol for maximal LDCL response were 100–200 ng/ml, 500 particles/PMN and 0.1 mmol/L, respectively. Concentrations of DMSO of 0.5–1% (v/v) did not significantly affect the maximal CL response of PMN. Gelatin concentrations of 0.1 –0.5 mg/ml had no effect on the LDCL of PMN. In addition, the LDCL of PMN was significantly correlated with bactericidal activity towardsS. aureus(r = 0.78,p < 0.001 for blood PMN andr = 0.66,p < 0.01 for milk PMN). Under the optimal experimental conditions for measurement of CL produced by bovine blood and milk PMN defined in this study, LDCL assay is an accurate and reproducible technique for the rapid quantification of PMN bactericidal activity in physiological and pathological conditions of high‐yielding dairy cows. Copyright © 2001 John Wiley & Sons, Ltd.
Dynamics of supercoiled and linear pTZ18U plasmids observed with a long‐lifetime metal–ligand complex
Authors: Kang Jung Sook , Abugo Omoefe O. , Lakowicz Joseph R.
Published: August 2002

The metal–ligand complex, [Ru(bpy)2(dppz)]2+ (bpy = 2,2′‐bipyridine, dppz = dipyrido[3,2‐a:2′,3′‐c]phenazine) (Ru‐BD), was used as a spectroscopic probe for studying nucleic acid dynamics. The Ru‐BD complex displays a long lifetime of over 100 ns and a molecular light switch property upon DNA binding due to shielding of its dppz ligand from water. To further show the usefulness of this luminophore (Ru‐BD) for probing DNA dynamics, we examined its intensity and anisotropy decays when intercalated into supercoiled and linear pTZ18U plasmids using frequency‐domain fluorometry with a light‐emitting diode (LED) as the modulated light source. Compared to the supercoiled plasmids with an average intensity decay time of 120.8 ns at 25°C, we obtained somewhat longer lifetimes for the linear plasmids (〈τ〉 = 141.4 ns at 25°C), suggesting a more efficient shielding from water by the linear plasmids. The anisotropy decay data also showed longer rotational correlation times for the linear plasmids (495 and 35 ns at 25°C) as compared to the supercoiled plasmids (412 and 27 ns at 25°C). The slow and fast rotational correlation times appear to be consistent with the bending and torsional motions of the plasmids, respectively. The anisotropy values were quite similar, although the values of the supercoiled plasmids were slightly higher in both the steady‐state and anisotropy decay measurements. These results indicate that Ru‐BD can be applied in the study of both bending and torsional dynamics of nucleic acids. © 2002 John Wiley & Sons, Inc. Biopolymers (Biospectroscopy) 67: 121–128, 2002
Protein unfolding during reversed‐phase chromatography: I. Effect of surface properties and duration of adsorption
Authors: McNay Jennifer L. M. , Fernandez Erik J.
Published: August 2002

Residue‐level features of bovine pancreatic trypsin inhibitor (BPTI) unfolding on reversed‐phase chromatography (RPC) surfaces were investigated using hydrogen–deuterium exchange labeling and NMR. A set of silica‐based RPC surfaces was used to examine the influence of alkyl chain length and media pore size on adsorbed BPTI conformation. In all cases there was substantial unfolding in the adsorbed state; however, residual protection from exchange was consistently observed. Particle pore size did not influence conformation substantially for C4‐alkyl modified silica; however, 120 Å pore C18 media produced more hydrogen exchange than any other surface examined. In this case, the radius of curvature inside the pore approaches the size of the BPTI molecule. Generally, the pattern of hydrogen exchange protection was uniform; however, the β‐sheet region was selectively protected on the large‐pore C18 media. The β‐sheet region forms a hydrophobic core that forms early when BPTI folds in solution. This suggests that partially unfolded states possessing a native‐like structure play an important role in adsorption and elution in RPC. Finally, increased contact time with the surface before elution fostered unfolding and altered chromatographic behavior considerably. © 2001 John Wiley & Sons, Inc. Biotechnol. Bioeng. 76: 224–232, 2001.
Biokinetic models for representing the complete inhibition of microbial activity at high substrate concentrations
Authors: Alagappan Gunaseelan , Cowan Robert M.
Published: August 2002

This paper reintroduces the Wayman and Tseng model for representing substrate inhibition effects on specific growth rate by further documenting its potential predictive capabilities. It also introduces a modification to this model in which an Andrews inhibition function is used in place of the Monod noninhibitory substrate function. This modification better represents the relationship between specific growth rate and substrate concentration for those substrates that show Andrews type inhibition at lower substrate concentrations, rather than the Monod type noninhibitory behavior described in the model of Wayman and Tseng. Results from nonlinear, least squares regression analysis are used to evaluate the ability of these models to empirically represent experimental data (both new and from the literature). The statistical goodness of fit is evaluated by comparing the regression results against those obtained using other empirical models. Finally, possible mechanisms of toxicity responsible for the observed inhibition trends are used to further justify use of these empirical models. The dominant mechanism considered to be relevant for conceptually explaining complete inhibition at high concentrations of solvents is the deterioration of cell membrane integrity. Literature citations are used to support this argument. This work should lead to improvements in the mathematical modeling of contaminant fate and transport in the environment and in the simulation of microbial growth and organic compound biodegradation in engineered systems. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 75: 393–405, 2001.
Stoichiometry and kinetics of acetate uptake under anaerobic conditions by an enriched culture of phosphorus‐accumulating organisms at different pHs
Authors: Filipe Carlos D. M. , Daigger Glen T. , Grady C. P. Leslie
Published: August 2002

The effect of pH on the stoichiometry and kinetics of acetate uptake by phosphorus‐accumulating organisms (PAOs) was studied. The stoichiometry of glycogen consumption and poly‐β‐hydroxy‐alkanoates (PHA) accumulation was independent of the pH over the range 6.5 to 8.0. It was again demonstrated that the amount of phosphorus released per acetate taken up (P/Hac ratio) was linearly dependent on pH, because of additional energy requirements for acetate transport at higher pH. The slope of this relationship was similar to that in previously published work, but the absolute values were different, indicating that the P/Hac ratio is the most variable stoichiometric parameter associated with the anaerobic metabolism of PAOs. A kinetic expression for acetate‐uptake rate was developed and tested. It assumes a zero‐order form when the polyphosphate content of the biomass is not limiting. When the polyphosphate content becomes low, the rate is significantly decreased. The expression was tested in situations in which polyphosphate was a limiting factor in the rate of acetate uptake, in which the glycogen content of the biomass became very low, and in which both glycogen and polyphosphate were present in excess. The model was able to simulate the three situations adequately. Additionally, the rate of acetate uptake was independent of the pH for the range studied (6.5 to 8.0). © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 76: 32–43, 2001.
Primary recovery of a genetically engineered Trichoderma reesei endoglucanase I (Cel 7B) fusion protein in cloud point extraction systems
Authors: Collén Anna , Selber Klaus , Hyytiä Teppo , Persson Josefine , Nakari‐Setlä Tiina , Bailey Michael , Fagerström Richard , Kula Maria‐Regina , Penttilä Merja , Stålbrand Henrik , Tjerneld Folke
Published: August 2002

Here we present data to demonstrate how partitioning of a hydrophilic enzyme can be directed to the hydrophobic detergent‐enriched phase of an aqueous two‐phase system by addition of short stretches of amino acid residues to the protein molecule. The target enzyme was the industrially important endoglucanase I, EGI (endo‐1,4‐β‐D‐glucan‐4‐glucanohydrolase, EC 3.2.1.4, Cel7B) of Trichoderma reesei. We investigated the partitioning of three EGI variants containing various C‐terminal peptide extensions including Trp‐Pro motifs of different lengths and localizations. Additionally, a recently developed system composed of the thermoseparating copolymer HM‐EOPO was utilized to study the effects of fusion tags. The addition of peptides containing tryptohan residues enhanced the partitioning of EGI to the HM‐EOPO‐rich phase. The system composed of a nonionic detergent (Agrimul NRE1205) resulted in the highest partition coefficient (K = 31) and yield (90%) with the construct EGIcore‐P5(WP)4 containing (Trp‐Pro)4 after a short linker stretch. A recombinant strain of T. reesei Rut‐C30 for large‐scale production was constructed in which the fusion protein EGIcore‐P5(WP)4 was expressed from the strong promoter of the cellulase gene cbh1. The fusion protein was successfully expressed and secreted from the fungus during shake‐flask cultivations. Cultivation in a 28‐L bioreactor however, revealed that the fusion protein is sensitive to proteases. Consequently, only low production levels were obtained in large‐scale production trials. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 78: 385–394, 2002.
Influence of glucose solubility and dissolution rate on the kinetics of lipase catalyzed synthesis of glucose laurate in 2‐methyl 2‐butanol
Authors: Flores Maria Victoria , Naraghi Kaynoush , Engasser Jean‐Marc , Halling Peter J.
Published: August 2002

The lipase catalyzed acylation of glucose by dodecanoic acid in 2‐methyl 2‐butanol was studied. The initial reaction rate was strongly dependent on the dissolved glucose concentration in the medium. Several methods were shown to increase dissolved glucose concentrations and initial reaction rates, namely, the use of solid β‐glucose, amorphous solid glucose, and supersaturated glucose solution. Supersaturated glucose solutions in 2‐methyl 2‐butanol showed a high stability even in the presence of solid crystalline glucose. During the reaction, the dissolved glucose concentration falls as the reaction proceeds, before recovering later as more of the excess solid dissolves. However, the ester synthesis rate continues to fall even after glucose concentration reaches its minimum, so glucose dissolution rate limitation is not responsible for the synthesis rate decline. Experiments with added molecular sieves show that the main reason is the accumulation of product water. In the presence of molecular sieves, 70% of glucose was converted to ester, independent of the initial soluble glucose in the medium. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 78: 815–821, 2002.
Unexpectedly enhanced stereoselectivity of peroxidase‐catalyzed sulfoxidation in branched alcohols
Authors: Xie Yuchun , Das Prasanta Kumar , Caaveiro Jose M. M. , Klibanov Alexander M.
Published: August 2002

Lyophilized horseradish peroxidase (HRP) exhibits poor stereoselectivity in the sulfoxidation of thioanisole when the enzyme is either redissolved in water or suspended in organic solvents. However, when HRP is co‐lyophilized in the presence of lyoprotectants or ligands, its stereoselectivity, although still low in most organic solvents, increases up to 4‐fold if assayed in secondary or tertiary alcohols (but not in their linear isomers). A mechanistic hypothesis is presented explaining this puzzling phenomenon on the basis of a model of the active site of the enzyme‐substrate complex derived from its X‐ray crystal structure by means of molecular dynamics and energy minimization. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 79: 105–111, 2002.
Dynamic volume‐averaged model of heat and mass transport within a compost biofilter: I. Model development
Authors: Mysliwiec Mitchell J. , VanderGheynst Jean S. , Rashid Mark M. , Schroeder Edward D.
Published: August 2002

Successful, long‐term operation of a biofilter system depends on maintaining a suitable biofilm environment within a porous medium reactor. In this article a mathematical study was conducted of the spatial and temporal changes of biofilter performance due to interphase heat and mass transport. The method of volume averaging was used to spatially smooth the three‐phase (solid, liquid, and gas) conservation equations over the biofilter domain. The packing medium was assumed to be inert, removing the solid phase mass continuity equation from the system. The finite element method was used to integrate the resulting nonlinear‐coupled partial differential equations, tracking eight state variables: temperature, water vapor, dry air, liquid water, biofilm, gas and liquid phase organic pollutant, and nutrient densities, through time and space. A multiphase, gas and liquid flow model was adapted to the biofilter model from previous studies of unsaturated groundwater flow. Newton's method accelerated by an LU direct solver was used to iterate the model for solutions. Effects of packing media on performance were investigated to illustrate the utility of the model. The moisture dynamics and nutrient cycling are presented in Part II of this article. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 73: 282–294, 2001.
Strength of mid‐logarithmic and stationary phase Saccharopolyspora erythraea hyphae during a batch fermentation in defined nitrate‐limited medium
Authors: Stocks Stuart M. , Thomas Colin R.
Published: August 2002

A method for measuring mechanical properties of Saccharopolyspora erythraea is reported with data from a batch fermentation. Briefly, hyphae were glued to the end of a tungsten filament mounted horizontally on a sensitive force transducer. Free ends of hyphae were trapped against a flat surface by a second probe. The force transducer and tungsten filament were then moved at a fixed rate, the hypha were strained, and the force resisting motion recorded. From these data the maximum force resisting motion is taken as the force at which breakage occurs. Hyphae from the mid‐logarithmic phase of a simple batch fermentation on defined medium were found to have a breaking force of 890 ± 160 nN (95% confidence), while stationary phase hyphae were weaker at 580 ± 150 nN. Video recordings of the experiments allowed an approximation of breaking strain, which did not differ significantly between samples at 0.18 ± 0.03. Electron microscopy was used to measure cell wall thickness, cell diameter, and hence cell wall cross‐sectional area. The ultimate tensile strength was estimated to be 24 ± 3 MPa with no difference between the two samples, the lower breaking force of the stationary phase hyphae being attributed to a thinner cell wall. Assuming a linear relationship between stress and strain, the elastic modulus was estimated to be 140 ± 30 MPa. These values are comparable with other structural biological materials such as yeast cell walls and collagen. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 73: 370–378, 2001.
Sol‐gel immobilization of serine proteases for application in organic solvents
Authors: van Unen Dirk‐Jan , Engbersen Johan F. J. , Reinhoudt David N.
Published: August 2002

The serine proteases α‐chymotrypsin, trypsin, and subtilisin Carlsberg were immobilized in a sol‐gel matrix and the effects on the enzyme activity in organic media are evaluated. The percentage of immobilized enzyme is 90% in the case of α‐chymotrypsin and the resulting specific enzyme activity in the transesterification of N‐acetyl‐L‐phenylalanine ethyl ester with 1‐propanol in cyclohexane is 43 times higher than that of a nonimmobilized lyophilized α‐chymotrypsin. The activities of trypsin and subtilisin Carlsberg are enhanced with 437 and 31 times, respectively. The effect of immobilization on the enzyme activity is highest in hydrophobic solvents. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 75: 154–158, 2001.
Investigation of binding process of chlorpromazine to bovine serum albumin by means of passive and active experiments
Authors: Rukhadze Marina D. , Bezarashvili George S. , Sidamonidze Nino Sh. , Tsagareli Sonya K.
Published: August 2002

The association process of chlorpromazine with bovine serum albumin by both onefactoral passive and multifactoral active experiments were investigated in model systems. The dependence of absolute concentration of the free fraction of chlorpromazine on the total concentration of chlorpromazine is described by the increasing function, but the dependence of the relative concentration (free/total) on this factor is influenced by external characteristics. The concentrations of chlorpromazine, bovine serum albumin and Tritons' mixture, as principal factors of a multifactoral experiment, influence the absolute and relative values of the free fraction of chlorpromazine non‐additively, ie the interaction of factors is significant. Copyright © 2001 John Wiley & Sons, Ltd.
Analysis of the glutathione conjugate of paracetamol in human liver microsomal fraction by liquid chromatography mass spectrometry
Authors: Thatcher Natalie J. , Murray Stephen
Published: August 2002

An assay based on microbore liquid chromatography–positive ion electrospray mass spectrometry with selected ion recording has been developed for the measurement of the glutathione conjugate of paracetamol (acetaminophen) in human hepatic microsomal incubations. A deuterated analogue of the glutathione conjugate was synthesized for use as an internal standard and extraction was carried out on Oasis™ solid phase extraction columns. The limit of quantification of the glutathione conjugate was 10 ng/incubation and the intra‐assay coefficient of variation at this concentration was 6.8%. Copyright © 2001 John Wiley & Sons, Ltd.

Abbreviations used:

ESI

electrosprayionization

NABQI

N‐acetyl‐p‐benzoquinoneimine

SIR

selected ion recording

SRM

selected reaction monitoring.
Validated analysis of fluvastatin in a pharmaceutical capsule formulation and serum by capillary electrophoresis
Authors: Doğrukol‐Ak Dilek , Kırcalı Kevser , Tunçel Muzaffer , Aboul‐Enein Hassan Y.
Published: August 2002

The capillary electrophoretic behavior and the determination of fluvastatin (FLU) in capsule and serum is described in this study. Method development was conducted in a fused‐silica capillary (L = 86 cm, Leff = 58 cm and 75 µm i.d.) and a background electrolyte consisting of 10 mM borate at pH 8 was used. The separation was performed by current‐controlled system applying 41 µA, detecting at 239 nm and injecting 0.5 s vacuum injection. A good electropherogram and excellent repeatability was obtained. FLU and phenobarbital sodium (internal standard) migrated (with RSD%) at 4.8 (0.3) min and 5.2 (0.6) min, respectively. Limit of detection (LOD) and limit of quantitation (LOQ) values were found to be 1 × 10−6 M and 2.89 × 10−6 M, respectively. Linearity in the range of 1.03 × 10−5 –5.15 × 10−5 M was examined employing intra‐day and inter‐day studies and well‐correlated calibration equations were obtained. FLU in a capsule (Lescol® 40 mg declared) was found to be 41.9 ± 0.4 mg. Furthermore, FLU was determined in serum applying standard addition technique. Good repeatability and no interference were observed. The method proposed is simple, sensitive, precise and easy to use for the determination of FLU in capsule and serum. Copyright © 2001 John Wiley & Sons, Ltd.

Abbreviations used:

FLU

fluvastatin

HMG‐CoA

hydroxymethylglutaryl coenzyme
World Wide Web resources for materials science
Authors: Abrate Serge
Published: August 2002

The internet makes technical information readily available in ways that were unthinkable a few years ago. This article shows how the World Wide Web (the web) can be used in a Materials Science class to enrich the educational process. Strategies for finding and evaluating information and are discussed. © 2002 Wiley Periodicals, Inc. Comput Appl Eng Educ 9: 238–247, 2001; Published online in Wiley InterScience (www.interscience.wiley.com.); DOI 10.1002/cae.10002
Development and evaluation of a computer‐based laboratory teaching tool
Authors: Avouris N. M. , Tselios N. , Tatakis E. C.
Published: August 2002

Effective evaluation of educational software is a key issue for successful introduction of advanced tools in the curriculum. This paper focuses on our experience of developing and evaluating a tool for computer‐assisted teaching of engineering laboratory courses. Various categories of educational softwares that can be used for laboratory courses are described. An example of such experimental system is also provided. Finally issues and techniques relating with usability evaluation of instructional software are described with examples of application of these techniques during the design and experimental use of electrical‐machines laboratory educational software. © 2001 John Wiley & Sons, Inc. Comput Appl Eng Educ 9: 8–19, 2001
Power system transient stability analysis software tool for an undergraduate curriculum
Authors: Muknahallipatna S. , Legowski Stanislaw , Ula Sadrul , Kopas Jason
Published: August 2002

This paper describes, a technique of the transient stability assessment, known as the Extended Equal Area Criterion (EEAC) as applied to a multimachine power system. The EEAC is implemented using the MATLAB program to provide a software tool with GUI. The software tool of the EEAC is developed to incorporate the transient stability analysis, into an undergraduate curriculum in power engineering. Another criterion for developing this software is to reduce the effort normally associated with the instruction of the complex theory of the transient stability and the use of the software in an undergraduate classroom environment. The results obtained from the MATLAB software on two multimachine power systems are compared with the traditional time domain analysis technique for verification purposes. © 2001 John Wiley & Sons, Inc. Comput Appl Eng Educ 9: 37–48, 2001
Child care practice innovations: using a model of change to develop training strategies
Authors: Horwath Jan
Published: August 2002

Modernizing health and social services is a major part of the current government agenda in England. As a consequence of this agenda, social workers and their managers are faced with new initiatives designed to increase the effectiveness of social services. Managers and trainers frequently find themselves in a difficult position; they are expected to introduce innovations to a workforce who can feel overwhelmed by the degree and pace of change, and as a consequence some workers can be hostile or resistant to learning about, and working with, new initiatives. This paper describes ways in which a theoretical model of change can be used to analyse likely workforce responses to policy and practice innovations. Based on this analysis, consideration is given to the implications of these responses for training and staff development. The application of the model to the design and delivery of a training strategy is explored: the Framework for the Assessment of Children in Need and Their Families (Department of Health, Department for Education and Employment and The Home Office, 2000) is used as a case example. (This framework is new assessment guidance issued by the Department of Health for use in England.) The paper describes ways in which the model can assist educators promote effective learning and support practitioners and their managers through major change. Copyright © 2001 John Wiley & Sons, Ltd.
‘Someone to talk to who'll listen’: addressing the psychosocial needs of children and families
Authors: Attride‐Stirling Jennifer , Davis Hilton , Markless Gill , Sclare Irene , Day Crispin
Published: August 2002

The paper presents the Lewisham Community Child and Family Service (LCCFS), a community‐based intervention providing psychosocial help for children, young people, parents and families. The service is focused on early intervention, prevention and promotion in the improvement of local health. It works under a service framework based on inter‐agency collaboration, and a counselling model based on community and interpersonal partnerships, grounded in personal construct theory (Kelly, 1955). The policy demands and local need for accessible and acceptable mental health are discussed, and quantitative and qualitative findings of the needs assessment preceding the establishment of the LCCFS are presented, supporting the need for community mental health provision. The feasibility for the LCCFS to reconcile and meet the policy demands and the needs of parents with respect to child psychosocial help and services are discussed. Copyright © 2001 John Wiley & Sons, Ltd.
Four‐dimensional analysis of cyclic changes in coronary artery shape
Authors: Liao Robert , Chen S.‐Y. James , Messenger John C. , Groves Bertron M. , Burchenal J.E.B. , Carroll John D.
Published: August 2002

The objective of this study was to derive a method for quantifying the dynamic geometry of coronary arteries. Coronary artery geometry plays an important role in atherosclerosis. Coronary artery geometry also influences the performance of coronary interventions. Conversely, implantation of stents may alter coronary artery geometry. Clinical tools to define vessel shape have not been readily available. Using a Frenet‐Serret curvature analysis applied to 3D reconstruction data derived from standard coronary angiograms, 21 coronary arteries were analyzed at end‐diastole (ED) and end‐systole (ES). Vessels were divided anatomically: type 1 consisted of vessels lying in the AV groove (left circumflex, right coronary) and type 2 consisted of vessels overlying actively contracting myocardium (left anterior descending, diagonal, obtuse marginal, right ventricular marginal, posterior descending, posterolateral). Vessel segments were analyzed by assessing the changes in curvature, torsion, and discrete flexion points (FPs), areas of systolic bending in the arterial contour. The curvature from ED to ES of type 1 vessels was unchanged (−0.02 ± 0.03 cm−1), while the curvature change of type 2 vessels showed a 38% increase (0.33 ± 0.04 cm−1; P < 0.001). Type 1 vessels had fewer FPs per vessel than type 2 vessels (0.38 ± 0.18 and 2.40 ± 0.23 FP/vessel, respectively; P < 0.001). FPs were more common in distal segments and branch vessels. A method to quantify cyclic changes in coronary artery shape was applied to 3D data sets derived from standard coronary angiograms. Coronary arteries undergo a cyclic change in shape resulting in changes in overall curvature as well as formation of discrete flexion points. These changes in vessel shape are asymmetrically distributed in coronary arteries. Cathet Cardiovasc Intervent 2002;55:344–354. © 2002 Wiley‐Liss, Inc.
Nondominant right coronary artery occlusion and ventricular tachyarrythmias
Authors: Rao Jayasree , Mascarenhas D.A.N. , Schiavone Joseph
Published: August 2002

It is usually considered that occlusion of a nondominant right coronary artery is not associated with significant consequences. We report two cases of nondominant right coronary artery occlusion that presented with sudden cardiac death. Timely intervention resulted in complete resolution of the ventricular arrhythmias. This highlights the need for greater vigilance in the recognition and treatment of these lesions. Cathet Cardiovasc Intervent 2002;56:53–57. © 2002 Wiley‐Liss, Inc.
Short‐ and long‐term results of emergency and elective percutaneous interventions on left main coronary artery stenoses
Authors: Sperker Wolfgang , Gyöngyösi Mariann , Kiss Katharina , Glogar Dietmar
Published: August 2002

In this prospective study, we analyzed the short‐ and long‐term outcomes of percutaneous interventions on significant left main coronary artery (LM) stenoses. Between January 1998 and June 2000, 18 patients underwent emergency interventions on unprotected LM stenoses (group 1), while 15 patients had elective interventions on protected LM stenoses (group 2). Despite a procedural success of 88.9% in group 1, event‐free in‐hospital and mortality rates were 50.0% and 38.9%. After 6.4 ± 4.4 months of follow‐up, late event‐free survival and mortality rates were 33.3% and 38.9%. In group 2, procedural success was 100%, with 100% event‐free in‐hospital survival; late event‐free survival and mortality rates were 93.3% and 0% after 6.7 ± 4.1 months of follow‐up. Emergency interventions on LM stenoses remain a procedure with high acute and mid‐term mortality. In spite of the high rate of major adverse cardiac events, an acceptable long‐term survival can be achieved. Cathet Cardiovasc Intervent 2002;56:22–29. © 2002 Wiley‐Liss, Inc.
Changes in coil morphology following transcatheter coil occlusion of the patent ductus arteriosus using a modified snare technique
Authors: Dobrolet Nancy C. , Ettedgui José A.
Published: August 2002

We observed a decrease in length of the Gianturco coils following transcatheter occlusion of the patent ductus arteriosus (PDA). Coil length was measured on chest radiograph within 24 hr of coil placement and compared to the length at the time of follow‐up. Echocardiograms were also reviewed for evidence of duct recanalization. Twenty‐seven patients met inclusion criteria. The median time to follow‐up was 5 months (1–12 months). Twenty‐four out of 27 (89%) patients had a decrease in coil length by 1.9 ± 1.1 mm (P < 0.01). This was an average decrease of 16%. One patient had an increase in length and two patients had no change in coil length. Nineteen out of 27 patients had echocardiograms. Despite the change in coil length, there was no evidence of flow acceleration in the pulmonary artery or descending aorta. No patients had evidence of duct recanalization. Cathet Cardiovasc Intervent 2001;52:504–509. © 2001 Wiley‐Liss, Inc.
Comparative trial of stent‐like balloon angioplasty versus coronary stenting for acute myocardial infarction
Authors: Eid‐Lidt Guering , Villavicencio‐Fernández Ramón , Ponce‐de‐León‐Rosales Sergio , Gaspar Jorge , Luna‐Guerra Jorge , Ban‐Hayashi Ernesto , Peña‐Duque Marco A. , Martinez‐Rios Marco A.
Published: August 2002

Primary PTCA has been shown to be superior to any thrombolytic regimen and offers higher reperfusion rates and better coronary flow grades. Its limitations include recurrent ischemia (10%–15%), infarct‐related artery reocclusion (5%–10%), angiographic restenosis (35%–50%), and need to perform repeat PTCA or CABG at 6‐month follow‐up (20%). Thus, the current role of coronary stenting for acute myocardial infarction (AMI) is very promising. From December 1995 through January 1997, 335 patients underwent primary angioplasty during the first 12 hr from symptom onset at our institution. We performed a retrospective study comparing the in‐hospital and 6‐month follow‐up outcome of 61 patients who underwent coronary stenting (stent group) against 61 patients with optimal (residual lesion stenosis < 30%) balloon‐only primary angioplasty (stent‐like group). Patients were routinely treated with aspirin, and ticlopidine was given only to the stent group. In‐hospital major adverse cardiac events (MACE) rate was 11.5% without statistical differences between the groups. Cardiac death rate was similar in both groups (4.9 vs. 6.6%; P = 1.0) and only two (3.3%) patients from the stent group and none from the PTCA group had nonfatal myocardial reinfarction. At 6‐month follow‐up, the rate of recurrent angina was higher in the stent‐like group (30.9 vs. 7.1%; P < 0.001). Multivariate analysis showed that only stenting of the infarct‐related artery was a borderline independent predictor for MACE (OR = 0; 95% CI = 0–1; P = 0.057). Primary stenting for AMI reduces the rate of recurrent angina or symptoms and MACE at 6‐month follow‐up. Cathet Cardiovasc Intervent 2001;53:149–154. © 2001 Wiley‐Liss, Inc.