bluuebunny/crossref_metadata_2025 huggingface dataset:
Electromechanical behavior of hybrid carbon/glass fiber composites with tension and bending
Authors: Cho Jae Whan , Choi Jun Sik , Yoon Young Sang
Published: August 2002

To understand the smart (i.e., good memory) characteristics of hybrid composites of carbon fibers (CFs) and glass fibers (GFs) with epoxy resin as a matrix, the changes in the electrical resistance of composites with tension and on bending were investigated. The electrical resistance behavior of composites under tension changed with the composition of the CF/GF, as well as with the applied strain. The fractional electrical resistance increased slowly with increasing strain within a relatively low strain region. However, with further loading it increased stepwise with the strain according to the fracture of the CF layers. The strain sensitivity of the samples increased with increasing CF weight percentage, and the samples incorporating more than 40 wt % CF showed a strain sensitivity higher than 1.54 for a single CF. The changes in the fractional electrical resistance with bending were not so dominant as those with tension. This difference was attributed to the action of two cancelling effects, which are the increasing and decreasing fractional electrical resistance due to tension and compression with bending, respectively. On recovery from a large applied bending, the fractional electrical resistance decreased slowly with unloading because of the increase of contacts between the fibers that resulted from the reorganization of ruptured CFs during the recovery. Even the composites incorporating a relatively small CF content showed an irreversible electrical resistance with both tension and bending. However, the strain sensitivity being larger with tension than with bending is ascribed to the difference in their mechanical behaviors. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2447–2453, 2002
Development of membranes by radiation grafting of acrylamide into polyethylene films: Properties and metal ion separation
Authors: Gupta Bhuvanesh , Anjum Nishat , Sen Kushal
Published: August 2002

Polyethylene‐g‐polyacrylamide membranes were prepared by graft polymerization of acrylamide into polyethylene films using a preirradiation technique. The membranes showed good swelling in water and a maximum of 232% swelling was achieved for a graft level of 590%. The electrical resistance of the membranes decreased with increase in the degree of grafting to 200% and then stabilized with a further increase in grafting to 590%. The membranes had an excellent binding capacity for mercury ions. Almost 99% mercury separation was achieved from a metal solution of 200 ppm. The metal binding capacity increased with increase in the degree of grafting in the membranes. A binding capacity as high as 6.2 mmol/g in a membrane with 590% grafting was achieved. The pH of the metal solution did not have any significant influence on the binding ability of the membranes. The mercury‐loaded membranes showed better thermal stability as compared to those without metal binding. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 282–291, 2002
Analysis of polymeric composite interphase regions with thermal atomic force microscopy
Authors: Tillman Matthew S. , Hayes Brian S. , Seferis James C.
Published: August 2002

Previous work on the characterization of interphase regions in thermosetting composite systems has focused on the inference of an interphase layer from effects noticed through macroscale mechanical and thermal testing. With the development of atomic force microscopy and active thermal probes for this technique, it is now possible to examine material thermal properties on a much smaller scale. Variations in microscale thermal properties of an aerospace‐grade thermosetting resin system were evaluated for carbon and glass fiber reinforcement, using the modulated local thermal analysis mode of a TA Instruments 2990 μTA. The variations observed clearly demonstrate the presence of a soft interphase layer in the glass material and underline the importance of fiber–matrix interactions during the formation of the interphase. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1643–1649, 2001
Pulsed plasma deposition from 1,1,2,2‐tetrafluoroethane by electron cyclotron resonance and conventional plasma enhanced chemical vapor deposition
Authors: Labelle Catherine B. , Gleason Karen K.
Published: August 2002

Pulsed electron cyclotron resonance (ECR) plasmas from 1,1,2,2‐C2H2F4 are used to deposit fluorocarbon films. The deposited films have a F : C ratio of 1, with only slight variations in % CFx as the deposition pressure is decreased. The optical emission (OES) spectra of the pulsed C2H2F4 plasmas show high intensity peaks for H, C2, and C3, with lower intensity CF2 and F peaks. The dominant OES peak shifts from Hα to C2 when the pressure is reduced, most likely a result of the increased electron temperature at the lower pressure. Gas‐phase recombination reactions may be occurring between the OES sampling region and the deposition substrate (∼ 8‐in. distance), producing fluorocarbon molecular deposition species, thus accounting for the high degree of fluorination in the deposited films. Parallel plate plasma deposited films from C2H2F4 show less fluorination than their ECR counterparts, as well as vastly different OES spectra, with CF2 peaks dominating the spectra versus H and C2. The presence of ion bombardment in the parallel plate system tends to defluorinate the depositing films, and thus can account for the less fluorinated films deposited in the parallel plate versus ECR systems. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2084–2092, 2001
Novel optically active poly(amide‐imide)s with tetrahydropyrimidinone and tetrahydro‐2‐thioxopyrimidine moieties by microwave‐assisted polycondensation
Authors: Mallakpour Shadpour E. , Hajipour Abdol‐Reza , Faghihi Khalil , Foroughifar Naser , Bagheri Javad
Published: August 2002

Rapid and highly efficient synthesis of novel poly(amide‐imide)s (PAIs) were achieved under microwave irradiation by using a domestic microwave oven from the polycondensation reactions of 4,4′‐carbonyl‐bis(phthaloyl‐L‐alanine) diacid chloride [N,N′‐(4,4′‐carbonyldiphthaloyl)] bisalanine diacid chloride (1) with six different derivatives of tetrahydropyrimidinone and tetrahydro‐2‐thioxopyrimidine compounds (2a–2f) in the presence of a small amount of a nonpolar organic medium that acts as a primary microwave absorber. Suitable organic media was o‐cresol. The polycondensation proceeded rapidly and was almost completed within 10 min, giving a series of PAIs with inherent viscosities of about 0.25–0.45 dL/g. The resulting PAIs were obtained in high yield and are optically active and thermally stable. All of the above compounds were fully characterized by means of Fourier transform infrared spectroscopy, elemental analyses, inherent viscosity (ηinh), solubility test, and specific rotation. Thermal properties of the PAIs were investigated using thermogravimetric analysis. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2416–2421, 2001
Thermal and mechanical properties and water absorption of sodium dodecyl sulfate‐modified soy protein (11S)
Authors: Zhong Z. K. , Sun X. S.
Published: August 2002

The thermal and mechanical properties and water absorption of sodium dodecyl sulfate (SDS)‐modified 11S soy protein and molded plastics made from it were studied using differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), mechanical tests, and scanning electron microscopy (SEM). The DSC results showed that both the temperature and enthalpy of thermal denaturation of modified 11S solutions decreased as the SDS concentration increased. Nonfreezing water of the modified 11S solution had a minimum value at 1.0% SDS. The ordered structure of SDS‐modified 11S protein was recovered and/or newly formed during the freeze‐drying process. Both DSC and DMA results showed that SDS was a plasticizer of 11S, and the glass transition temperature of modified 11S plastics decreased with increasing SDS concentration. Both the tensile strength and elongation of modified 11S plastics first decreased and then increased as the SDS concentration increased, and 5.0% SDS‐modified 11S plastic had the highest tensile strength and elongation. The SEM observations supported these results. A water‐absorption test showed a reduction in the water resistance of 11S plastics after SDS modification. The rate of water absorption increased with increasing SDS concentration. The hydrophobic interaction between SDS molecules and 11S protein was found to have important effects on the thermal and mechanical properties and the water absorption of 11S plastics. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 166–175, 2001
Characterization of photo‐ and thermoresponsible amphiphilic copolymers having azobenzene moieties as side groups
Authors: Sugiyama Kazuo , Sono Kazuro
Published: August 2002

Two series of amphiphilic copolymers, poly(HPMA‐co‐MPAP) I–V with n = 0.05–0.29 of the molar ratio of MPAP and poly(HPMA‐co‐MPAH)‐I–V with n = 0.05–0.23 of the molar ratio of MPAH, were prepared by radical copolymerization of N‐(2‐hydroxypropyl) methacrylamide (HPMA) with azo‐monomers such as 4‐(4‐methoxyphenylazo) phenyl methacrylate (MPAP) and 6‐[4‐(4‐methoxyphenylazo) phenoxy] hexyl methacrylate (MPAH) using 2,2′‐azobisisobutyronitrile as an initiator. Self‐organization of these copolymers in water was confirmed by disappearance of the proton signal of the methoxyazobenzene in 1H‐NMR spectra measured in the solvent system of D2O and CD3OD. It was also found from the λmax, located near 344 nm, that azobenzene groups self‐organized to form the dimeric chromophore type of aggregate. The aqueous solutions of poly(HPMA‐co‐MPAP) and poly(HPMA‐co‐MPAH) exhibited the lower critical solution temperature (LCST) from at 68 to 40°C and from at 70 to 52°C in the dark state, respectively, with increasing the molar ratios of azo‐monomers. On the other hand, the LCST measured in the photostationary state showed the higher temperature by 2–4°C compared with that in the dark state. It was found that the adsorption of poly(HPMA‐co‐MPAP)‐V (n = 0.29) on polystyrene microspheres was photoregulated. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 3056–3063, 2001
Characterization of polyacrylamide‐grafted sodium alginate: A novel polymeric flocculant
Authors: Tripathy Tridib , Singh R. P.
Published: August 2002

The synthesis of sodium alginate‐g‐polyacrylamide was carried out by a ceric‐ion‐induced solution polymerization technique. Six grades of graft copolymers were synthesized by the variation of catalyst and monomer concentrations. These graft copolymers were characterized by intrinsic viscosity measurements, 13C‐NMR spectroscopy, infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, and X‐ray diffraction. From the characterizations, it could be concluded that there was a substantial amount of grafting with a minimum formation of homopolymer. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 3296–3308, 2001
Study on morphology of ternary polymer blends. I. Effects of melt viscosity and interfacial interaction
Authors: Hemmati M. , Nazokdast H. , Shariat Panahi H.
Published: August 2002

The morphology of some ternary blends was investigated. In all of the blends polypropylene, as the major phase, was blended with two different minor phases, ethylene–propylene–diene terpolymer (EPDM) or ethylene–propylene–rubber (EPR) as the first minor phase and high‐density polyethylene (HDPE) or polystyrene (PS) as the second minor phase. All the blends were investigated in a constant composition of 70/15/15 wt %. Theoretical models predict that the dispersed phase of a multiphase polymer blend will either form an encapsulation‐type phase morphology or phases will remain separately dispersed, depending on which morphology has the lower free energy or positive spreading coefficient. Interfacial interaction between phases was found to play a significant role in determining the type of morphology of these blend systems. A core–shell‐type morphology for HDPE encapsulated by rubber was obtained for PP/rubber/PE ternary blends, whereas PP/rubber/PS blends showed a separately dispersed type of morphology. These results were found to be in good agreement with the theoretical predictions. Steady‐state torque for each component was used to study the effect of melt viscosity ratio on the morphology of the blends. It was found that the torque ratios affect only the size of the dispersed phases and have no appreciable influence on the type of morphology. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1129–1137, 2001
Low‐modulus siloxane‐based polyurethanes. I. Effect of the chain extender 1,3‐bis(4‐hydroxybutyl)1,1,3,3‐tetramethyldisiloxane (BHTD) on properties and morphology
Authors: Adhikari Raju , Gunatillake Pathiraja A. , McCarthy Simon J. , Meijs Gordon F.
Published: August 2002

A series of eight polyurethane elastomers was prepared using a two‐step bulk polymerization procedure to investigate the effect of the siloxane chain extender 1,3‐bis(4‐hydroxybutyl)1,1,3,3‐tetramethyldisiloxane (BHTD) on polyurethane properties and morphology. All polyurethanes were based on 40 wt % hard segment derived from 4,4′‐methylenediphenyl diisocyanate (MDI) and a mixture of 1,4‐butanediol (BDO) and BHTD in varying molar ratios. The soft segment was based on an 80 : 20 (w/w) mixture of the macrodiols α,ω‐bis(6‐hydroxyethoxypropyl)polydimethylsiloxane (PDMS, MW 965) and poly(hexamethylene oxide) (PHMO, MW 714). Polyurethanes were characterized by size‐exclusion chromatography, tensile testing, differential scanning calorimetry, dynamic mechanical thermal analysis, and FTIR spectroscopy. Clear and transparent polymers were produced in all cases with number‐average molecular weights in the range of 90,000 to 111,000. The ultimate tensile strength decreased only slightly (15%), but Young's modulus and flexural modulus decreased by 76 and 72%, respectively, compared with that of the pure BDO extended polyurethanes as the amount of BHTD was increased to 40 mol %. This change resulted in “softer” and more elastic polyurethanes. Polyurethanes with BHTD contents above 40 mol % were more elastic but had poor tensile and tear strengths. A 60 : 40 molar ratio of BDO : BHTD produced a “soft” polyurethane, which combined good tensile strength and flexibility. The DSC and DMTA results confirmed that the incorporation of BHTD as part of the hard segment yielded polyurethanes with improved compatibility between hard and soft segments. IR data indicated that the amount of hard segments soluble in the soft‐segment phase increased with increasing BHTD, contributing to the improved phase mixing. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 736–746, 2002
Sponge morphological diversity: a qualitative predictor of species diversity?
Authors: Bell James J. , Barnes David K.A.
Published: August 2002

1. To the non‐specialist, problems are often associated with the quantification of sponge species diversity, as colour, shape and size can be highly variable within a single species. These variables can lead to an under‐estimation of the contribution of sponges to the biodiversity of the benthos especially during biological surveys.

2. Sponge species diversity (Shannon H′ values), richness (mean number of species) and morphological diversity (Shannon H′ values) were sampled at six sites (6 m depth intervals) on vertical (90°) and inclined surfaces (45°) experiencing different flow regimes at Lough Hyne Marine Nature Reserve (Ireland). Morphological diversity was sampled independently of species diversity. The time taken for the collection of both species and morphological diversity was recorded.

3. Morphological diversity was positively correlated with both sponge species diversity (r2=0.87, p<0.05) and sponge species richness (r2=0.70, p<0.05). Linear regression was found to be significant for both the relationships (p<0.05 for each F‐value). A sigmoidal relationship (r2=0.97, p<0.05) was found between morphological and species richness which proved to be significant (F‐value 40.67, p<0.05). Separate Bray–Curtis dendrograms and correspondence analysis of morphological and species community compositions at the six sites showed very similar clustering and four major clusters were identified.

4. The results of the present study indicate that sampling of sponge morphological diversity, rather than sponge species diversity and richness may be used as a qualitative estimate of sponge species diversity. Sampling of morphological diversity is much less time consuming, both in the field and laboratory, than collecting species diversity data and no specialist knowledge is required. Consideration is given to the use of such relationships in biological surveys and bio‐monitoring. Copyright © 2001 John Wiley & Sons, Ltd.
Basement membrane of mouse bone marrow sinusoids shows distinctive structure and proteoglycan composition: A high resolution ultrastructural study
Authors: Inoue S. , Osmond D.G.
Published: August 2002

Venous sinusoids in bone marrow are the site of a large‐scale traffic of cells between the extravascular hemopoietic compartment and the blood stream. The wall of the sinusoids consists solely of a basement membrane interposed between a layer of endothelial cells and an incomplete covering of adventitial cells. To examine its possible structural specialization, the basement membrane of bone marrow sinusoids has now been examined by high resolution electron microscopy of perfusion‐fixed mouse bone marrow. The basement membrane layer was discontinuous, consisting of irregular masses of amorphous material within a uniform 60‐nm‐wide space between apposing endothelial cells and adventitial cell processes. At maximal magnifications, the material was resolved as a random arrangement of components lacking the “cord network” formation seen in basement membranes elsewhere. Individual components exhibited distinctive ultrastructural features whose molecular identity has previously been established. By these morphological criteria, the basement membrane contained unusually abundant chondroitin sulfate proteoglycan (CSPG) revealed by 3‐nm‐wide “double tracks,” and moderate amounts of both laminin as dense irregular coils and type IV collagen as 1–1.5‐nm‐wide filaments, together with less conspicuous amounts of amyloid P forming pentagonal frames. In contrast, 4.5–5‐nm‐wide “double tracks” characteristic of heparan sulfate proteoglycan (HSPG) were absent. The findings demonstrate that, in comparison with “typical” basement membranes in other tissues, the bone marrow sinusoidal basement membrane is uniquely specialized in several respects. Its discontinuous nature, lack of network organization, and absence of HSPG, a molecule that normally helps to maintain membrane integrity, may facilitate disassembly and reassembly of basement membrane material in concert with movements of adventitial cell processes as maturing hemopoietic cells pass through the sinusoidal wall: the exceptionally large quantity of CSPG may represent a reservoir of CD44 receptor for use in hemopoiesis. Anat Rec 264:294–304, 2001. © 2001 Wiley‐Liss, Inc.
Characterization of azadirachtin binding to Sf9 nuclei in vitro
Authors: Nisbet Alasdair J. , Mordue (Luntz) A. Jennifer , Grossman Robert B. , Jennens Lyn , Ley Steven V. , Mordue William
Published: August 2002

[22,23‐3H2]dihydroazadirachtin was incorporated by Sf9 cells in culture and was bound specifically to the nuclear fraction. The observed association constant of the binding of the radioligand to a purified nuclear fraction was determined to be 0.037 ± 0.008 min–1 using a one‐phase exponential association equation, and binding appeared to be to a single population of sites. The binding was essentially irreversible, and the dissociation constant was estimated to be 0.00065 ± 0.00013 min–1. An association rate constant of 7.3 × 106 M–1 min–1 was calculated from these data. Binding was saturable, and the receptor number and affinity were determined as Bmax = 23.87 ± 1.15 pmol/mg protein, Kd = 18.1 ± 2.1 nM. The order of potency of semisynthetic azadirachtin analogues for competition for the binding site was as follows (IC50 in parentheses): azadirachtin (1.55 × 10–8 M) > dihydroazadirachtin (3.16 × 10–8 M) > dansyl dihydroazadirachtin (7.40 × 10–8 M) > DNP‐azadirachtin (7.50 × 10–8 M) > biotin dihydroazadirachtin (1.27 × 10–7 M) >> 11‐methoxy 22,23‐dihydroazadirachtin (6.67 × 10–7 M). Arch. Insect Biochem. Physiol. 34:461–473, 1997. © 1997 Wiley‐Liss, Inc.
Vitamin E uncouples joint destruction and clinical inflammation in a transgenic mouse model of rheumatoid arthritis
Authors: Bandt Michel De , Grossin Maggy , Driss Fathi , Pincemail Joël , Babin‐Chevaye Catherine , Pasquier Catherine
Published: August 2002

Objective

Reactive oxygen species are thought to play a role in rheumatoid arthritis (RA) in humans. We postulated that antioxidant treatment could have a beneficial effect in this disease. We therefore investigated the effects of vitamin E in the transgenic KRN/NOD mouse model of RA.

Methods

Mice were treated by gavage with oral vitamin E (α‐tocopherol). Clinical, histologic, and biochemical parameters were assessed for 6 weeks.

Results

Vitamin E treatment did not modify the clinical features of the disease (date of onset or disease intensity, as measured by the articular index), but it did prevent joint destruction, as measured by qualitative and semiquantitative analyses. Redox status did not differ between treated and control mice. White blood cell chemiluminescence was higher in transgenic KRN/NOD mice than in controls, but vitamin E treatment attenuated this difference. Vitamin E treatment of the transgenic animals led to a significant decrease in the levels of interleukin‐1β (IL‐1β) but not tumor necrosis factor α.

Conclusion

Vitamin E seems to uncouple joint inflammation and joint destruction in this model of RA, with a beneficial effect on joint destruction. Since many investigations are currently in progress to evaluate the benefit of interventions targeted toward anti‐IL‐1β, our findings suggest opportunities of therapeutic interest in human RA.
Delay to institution of therapy and induction of remission using single‐drug or combination–disease‐modifying antirheumatic drug therapy in early rheumatoid arthritis
Authors: Möttönen Timo , Hannonen Pekka , Korpela Markku , Nissilä Martti , Kautiainen Hannu , Ilonen Jorma , Laasonen Leena , Kaipiainen‐Seppänen Oili , Franzen Per , Helve Tapani , Koski Juhani , Gripenberg‐Gahmberg Marianne , Myllykangas‐Luosujärvi Riitta , Leirisalo‐Repo Marjatta
Published: August 2002

Objective

To study the impacts of 1) the delay from the onset of symptoms to the institution of disease‐modifying antirheumatic drug (DMARD) therapy, 2) two treatment strategies (treatment with a combination of DMARDs or with a single drug), and 3) the presence of HLA–DRB1 alleles (shared epitope) on the prediction of disease remission after 2 years in patients with early rheumatoid arthritis (RA).

Methods

In the FIN‐RACo (FINnish Rheumatoid Arthritis Combination therapy) trial, 195 patients with recent‐onset RA (median duration 6 months) were randomly assigned to receive either 1) a combination of DMARDs (sulfasalazine, methotrexate, hydroxychloroquine, and prednisolone) or 2) a single DMARD with or without prednisolone. The presence of a shared epitope was tested for in 165 of the 178 patients completing the study. The additional variables of age, sex, presence of rheumatoid factor, number of fulfilled American College of Rheumatology criteria for the classification of RA, and length of delay from onset of symptoms to institution of therapy were entered into a logistic regression model to determine the significant predictors for remission at 2 years.

Results

The delay to therapy (cut point of 4 months) was the only significant predictor for remission in patients treated using the single‐DMARD strategy, while no variable was a significant predictor for remission in those treated using the combination‐DMARD strategy. The frequency of achieving remission in the combination‐DMARD group after 2 years was similar in patients with short (0–4 months) and long (>4 months) delay periods (11 of 26 patients and 22 of 53 patients, respectively [∼42% in each group]), while the corresponding frequencies in the single‐DMARD group were 8 of 23 patients (35%) and 7 of 63 patients (11%) (P = 0.021). The presence of a shared epitope was not related to the induction of remission.

Conclusion

The delay of a few months from the onset of symptoms to institution of therapy decreases the ability of the traditional single‐drug strategy to induce remission in early RA.
Temporal arteritis and Chlamydia pneumoniae: Failure to detect the organism by polymerase chain reaction in ninety cases and ninety controls
Authors: Regan Michael J. , Wood Billie Jo , Hsieh Yu‐Hsiang , Theodore Mellisa L. , Quinn Thomas C. , Hellmann David B. , Green W. Richard , Gaydos Charlotte A. , Stone John H.
Published: August 2002

Objective

To examine the reported correlation between the presence of Chlamydia pneumoniae in temporal artery biopsy specimens and the diagnosis of temporal arteritis (TA).

Methods

Among 90 possible cases of TA identified at our institution between 1968 and 2000, 79 of the positive biopsy specimens (88%) demonstrated giant cells and the other 11 cases (12%) had other histopathologic features compatible with TA; by chart review, all 90 patients were confirmed to have met the American College of Rheumatology classification criteria for TA. Controls had negative temporal artery biopsy specimens during the same 32‐year time period and their postbiopsy disease courses were not compatible with TA. Controls were matched with each case by sex, year of biopsy, and age within 10 years. The biopsy specimens from all cases and controls were reevaluated and readings were confirmed in a masked manner by an experienced eye pathologist. Polymerase chain reaction (PCR) analyses for C pneumoniae were performed on the 180 samples using 2 different sets of PCR primers (which target 2 different genes). A primer set targeting the ompA gene (CP1‐CP2/CPC‐CPD) was used to perform a nested PCR, followed by confirmation of the findings with primers targeting the 16S ribosomal RNA (rRNA) gene (Cpn90/Cpn91) in a touchdown‐enzyme time‐release PCR. We used positive and negative controls, as well as controls made from infected and noninfected HEp‐2 cells, suspended in a formalin‐fixed, paraffin‐embedded matrix.

Results

Seventy‐six percent of the 180 cases and controls were women. The mean age of the cases was 72.0 years (range 53–90), and that of the controls was 70.4 years (range 51–86). Eighty percent of the control samples were obtained by temporal artery biopsy performed within 1 year of the biopsies performed on the matched cases. Using the CP1‐CP2/CPC‐CPD primer set, only 1 TA case sample (1% of all case samples) was positive for the ompA gene. One control sample was also positive using these primers. With the Cpn90/Cpn91 primers, none of the cases and none of the controls were positive for the 16S rRNA gene.

Conclusion

The results of this study using sensitive and specific PCR analyses do not support a role for C pneumoniae in the pathogenesis of TA.
Methods for measuring search engine performance over time
Authors: Bar‐Ilan Judit
Published: August 2002

This study introduces methods for evaluating search engine performance over a time period. Several measures are defined, which as a whole describe search engine functionality over time. The necessary setup for such studies is described, and the use of these measures is illustrated through a specific example. The set of measures introduced here may serve as a guideline for the search engines for testing and improving their functionality. We recommend setting up a standard suite of measures for evaluating search engine performance.
Effect of electrical stimulation on musculoskeletal systems; A meta‐analysis of controlled clinical trials
Authors: Akai Masami , Hayashi Kunihiko
Published: August 2002

This study was a meta‐analysis to examine whether electrical stimulation has specific effects in the healing of musculoskeletal repair process and in the diminution of symptoms with bone and joint disorders. Using MEDLINE (1966–1999) and EMBASE (1985–1999) a search for articles was carried out with four medical subject headings. Data were extracted from all the accessed articles and additionally collected from appropriate journal lists. A total of 20 randomized controlled trials on bones was identified which assessed healing of fractures, bone graft, and other conditions; and 29 randomized controlled trials on soft tissues and joints were also found, dealing with healing of skin wounds or dermal ulcers, soft tissue injury, and other conditions. Using criteria through which the quality of studies was assessed, the content of the articles was reorganized into a tabular form. The majority of the identified articles reported positive findings, but all the trials showed methodological flaws to some extent. Because of heterogeneity of the studies and the various outcome measurements, pooling of only part of the data was performed. The combined results of 12 trials on bones and 16 trials on soft tissues, the cases in which major endpoints were mainly union or healing rate, revealed statistically significant effects. The studies in this review had some methodological limitations, and the selected pooled trials do not constitute acceptable proof that electrical stimulation has specific effects on health. However, one cannot ignore the statistically significant positive findings reported in the trials, from which extracted data were able to be combined. Bioelectromagnetics 23:132–143, 2002. © 2002 Wiley‐Liss, Inc.
Use of spot measurements for assessing residential ELF magnetic field exposure: A validity study
Authors: Eskelinen Tuomo , Keinänen Jari , Salonen Heidi , Juutilainen Jukka
Published: August 2002

The purpose of this study was to evaluate residential short term “spot” measurements as surrogates for long term personal magnetic field (MF) exposure. In an epidemiological study on birth weight and pregnancy delay, MF exposure was assessed by taking five spot measurements in each room. For a subsample of 30 subjects 24 h personal MF measurements were made, and the following exposure metrics were calculated: 24 h arithmetic mean, 24 h median, percentage of time above 0.15 μT, and percentage of time above 0.29 μT. The 24 h exposure metrics were used as gold standards, when evaluating the validity of various summary measures calculated from spot measurements for assessing personal exposure. Based on Spearman correlation coefficient (r), specificity and sensitivity, the average of the spot measurements of a residence resulted in least exposure measurement error (misclassification). Also the above bed spot value correlated better with the 24 h metrics than any room average. Spot measurements performed about equally well in predicting different types of exposure metrics. Bioelectromagnetics 23:173–176, 2002. © 2002 Wiley‐Liss, Inc.
Modularity in vertebrate brain development and evolution
Authors: Redies Christoph , Puelles Luis
Published: August 2002

Embryonic modularity and functional modularity are two principles of brain organization. Embryonic modules are histogenetic fields that are specified by position‐dependent expression of patterning genes. Within each embryonic module, secondary and higher‐level pattern formation takes places during development, finally giving rise to brain nuclei and cortical layers. Defined subsets of these structures become connected by fiber tracts to form the information‐processing neural circuits, which represent the functional modules of the brain. We review evidence that a group of cell adhesion molecules, the cadherins, provides an adhesive code for both types of modularity, based on a preferentially homotypic binding mechanism. Embryonic modularity is transformed into functional modularity, in part by translating early‐generated positional information into an array of adhesive cues, which regulate the binding of functional neural structures distributed across the embryonic modules. Brain modularity may provide a basis for adaptability in evolution. BioEssays 23:1100–1111, 2001. © 2001 John Wiley & Sons, Inc.
Vascular endothelial growth factor (VEGF), a survival factor for tumour cells: Implications for anti‐angiogenic therapy
Authors: Harmey Judith H. , Bouchier‐Hayes David
Published: August 2002

Angiogenesis is central to both the growth and metastasis of solid tumours. Anti‐angiogenic strategies result in blood vessel regression accompanied by tumour cell apoptosis. Radiotherapy and many chemotherapeutic agents kill tumours by inducing apoptotic cell death. We propose that, in addition to its role as an angiogenic factor, vascular endothelial growth factor (VEGF) can act as a survival factor for tumour cells protecting them from apoptosis. Thus anti‐angiogenics, in particular those directed against VEGF, have multiple anti‐tumour effects. We suggest that anti‐VEGF strategies prevent vessel growth and block a tumour cell survival factor, VEGF, rendering tumour cells more sensitive to chemotherapy and radiotherapy. In addition, as chemotherapy and radiotherapy have been shown to increase VEGF expression, anti‐VEGF strategies may overcome therapy‐ induced tumour cell resistance. BioEssays 24:280–283, 2002. © 2002 Wiley Periodicals, Inc.; DOI 10.1002/bies.10043
Scale‐free networks in biology: new insights into the fundamentals of evolution?*
Authors: Wolf Yuri I. , Karev Georgy , Koonin Eugene V.
Published: August 2002

Scale‐free network models describe many natural and social phenomena. In particular, networks of interacting components of a living cell were shown to possess scale‐free properties. A recent study(1) compares the system‐level properties of metabolic and information networks in 43 archaeal, bacterial and eukaryal species and claims that the scale‐free organization of these networks is more conserved during evolution than their content. BioEssays 24:105–109, 2002. Published 2002 Wiley Periodicals, Inc.
Fascins, and their roles in cell structure and function
Authors: Kureishy Nina , Sapountzi Vasileia , Prag Soren , Anilkumar N. , Adams Josephine Clare
Published: August 2002

The fascins are a structurally unique and evolutionarily conserved group of actin cross‐linking proteins. Fascins function in the organisation of two major forms of actin‐based structures: dynamic, cortical cell protrusions and cytoplasmic microfilament bundles. The cortical structures, which include filopodia, spikes, lamellipodial ribs, oocyte microvilli and the dendrites of dendritic cells, have roles in cell–matrix adhesion, cell interactions and cell migration, whereas the cytoplasmic actin bundles appear to participate in cell architecture. We discuss the current understanding of the cellular mechanisms that regulate the binding of fascin to actin and how these processes contribute to the organisation or disassembly of cell protrusions. Although the in vivo roles of fascin have been studied principally in Drosophila, several human diseases are associated with inherited or acquired alterations in the expression of fascins. Strategies to modulate fascin‐containing protrusions and thereby cell adhesive and migratory behaviour could have potential for therapeutic intervention in these conditions. The supplementary material referred to in this section can be found at http://www.interscience.wiley.com/jpages/0265‐9247/suppmat/2002/v24.350.html BioEssays 24:350–361, 2002. ©2002 Wiley Periodicals, Inc.
Search for enhancers: teleost models in comparative genomic and transgenic analysis of cis regulatory elements
Authors: Müller Ferenc , Blader Patrick , Strähle Uwe
Published: August 2002

Homology searches between DNA sequences of evolutionary distant species (phylogenetic footprinting) offer a fast detection method for regulatory sequences. Because of the small size of their genomes, tetraodontid species such as the Japanese pufferfish and green spotted pufferfish have become attractive models for comparative genomics. A disadvantage of the tetraodontid species is, however, that they cannot be bred and manipulated routinely under laboratory conditions, so these species are less attractive for developmental and genetic analysis. In contrast, an increasing arsenal of transgene techniques with the developmental model species zebrafish and medaka are being used for functional analysis of cis regulatory sequences. The main disadvantage is the much larger genome. While comparison between many loci proved the suitability of phylogenetic footprinting using fish and mammalian sequences, fast rate of change in enhancer structure and gene duplication within teleosts may obscure detection of homologies. Here we discuss the contribution and potentials provided by different teleost models for the detection and functional analysis of conserved cis‐regulatory elements. BioEssays 24:564–572, 2002. © 2002 Wiley Periodicals, Inc.
Analysing gene function after duplication
Authors: Massingham T. , Davies L. J. , Liò P.
Published: August 2002

After gene duplication, mutations cause the gene copies to diverge. The classical model predicts that these mutations will generally lead to the loss of function of one gene copy; rarely, new functions will be created and both duplicate genes are conserved. In contrast, under the subfunctionalization model both duplicates are preserved due to the partition of different functions between the duplicates. A recent study(1) provides support for the subfunctionalization model, identifying several expressed gene duplicates common to humans and mice that contain regions conserved in one duplicate but variable in the other (and vice versa). We discuss both the methodology used in this study and also how gene phylogeny may lead to additional evidence for the importance of subfunctionalization in the evolution of new genes. BioEssays 23:873–876, 2001. © 2001 John Wiley & Sons, Inc.
Measurement of bioreactor perfusion using dynamic contrast agent‐enhanced magnetic resonance imaging
Authors: Thelwall Peter E. , Neves André A. , Brindle Kevin M.
Published: August 2002

Dynamic magnetic resonance imaging was used to monitor solute diffusion through aggregates of Chinese hamster ovary cells growing on macroporous carriers in a fixed‐bed bioreactor. Diffusion‐weighted 1H magnetic resonance imaging (MRI) and scanning electron microscopy demonstrated that cell growth in the bioreactor was heterogeneous, with the highest cell densities being found at the periphery of the carriers. T1‐weighted magnetic resonance imaging measurements of the inflow of a commonly used magnetic resonance contrast agent, gadolinium‐diethylenetriaminopentaacetic acid (Gd‐DTPA), showed that migration of the agent through the peripheral cell masses could be explained by diffusion. However, appearance of the contrast agent in the center of the carriers was too fast to be explained by simple diffusion and indicated that these regions were perfused by convective flow. The average diffusivity of Gd‐DTPA through the cell mass was found to be (2.4 ± 0.2) × 10−10 m2 sec− (mean ± SEM). This technique will be useful in the characterization and development of high‐cell‐density bioreactor systems, in which solute transport plays a critical role in cell growth and physiology. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 75: 682–690, 2001.
Influence of water activity on the enantioselective esterification of (R,S)‐ibuprofen by crosslinked crystals of Candida antarctica lipase B in organic solvent media
Authors: Pepin Pierre , Lortie Robert
Published: August 2002

The lipase B from Candida antarctica was purified from a commercial source and crystalized. The microcrystals were crosslinked using glutaraldehyde. The crosslinked crystals were then used to catalyze the esterification of (R,S)‐ibuprofen with dodecanol in octane at various water activities. As for the commercial preparation immobilized on acrylic resin, Novozym 435, low water activities foster better enantioselectivity, and the maximum reaction rates are obtained for aW = 0.1. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 75: 559–562, 2001.
Self‐assembly and two‐dimensional patterning of cell arrays by electrophoretic deposition
Authors: Brisson Vanessa , Tilton Robert D.
Published: August 2002

Using Saccharomyces cerevisiae as a demonstration system, we present a method to form two‐dimensional, patternable cellular arrays. The method does not require surface chemical templating of the substratum to produce arrays or patterns. By virtue of their colloidal characteristics, S. cerevisiae cells may be induced to form dense, quasi‐ordered two‐dimensional clusters adjacent to an electrode surface by electrophoretic deposition (EPD). Using ac EPD, dense two‐dimensional cell clusters may be formed in minutes from extremely dilute cell suspensions. The arrays may be induced to form geometric patterns by focusing the electric field during deposition. These monolayer arrays are reversible, dissipating by diffusion on removal of the electric field, and are not in adhesive contact with the electrode surface. Brief application of a modest dc current density adheres the arrays tightly to the surface. © 2002 John Wiley & Sons, Inc. Biotechnol Bioeng 77: 290–295, 2002.
Engineering of baker's yeasts, E. coli and Bacillus hosts for the production of Bacillus subtilis Lipase A
Authors: Sánchez Marta , Prim Núria , Rández–Gil Francisca , Pastor F. I. Javier , Diaz Pilar
Published: August 2002

Lipases are versatile biocatalists showing multiple applications in a wide range of biotechnological processes. The gene lipA coding for Lipase A from Bacillus subtilis was isolated by PCR amplification, cloned and expressed in Escherichia coli, Saccharomyces cerevisiae and Bacillus subtilis strains, using pBR322, YEplac112 and pUB110‐derived vectors, respectively. Lipase activity analysis of the recombinant strains showed that the gene can be properly expressed in all hosts assayed, this being the first time a lipase from bacterial origin can be expressed in baker's S. cerevisiae strains. An important increase of lipase production was obtained in heterologous hosts with respect to that of parental strains, indicating that the described systems can represent a useful tool to enhance productivity of the enzyme for biotechnological applications, including the use of the lipase in bread making, or as a technological additive. © 2002 Wiley Periodicals, Inc. Biotechnol Bioeng 78: 339–345, 2002.
Probing the performance limits of the Escherichia coli metabolic network subject to gene additions or deletions
Authors: Burgard Anthony P. , Maranas Costas D.
Published: August 2002

An optimization‐based procedure for studying the response of metabolic networks after gene knockouts or additions is introduced and applied to a linear flux balance analysis (FBA) Escherichia coli model. Both the gene addition problem of optimally selecting which foreign genes to recombine into E. coli, as well as the gene deletion problem of removing a given number of existing ones, are formulated as mixed‐integer optimization problems using binary 0–1 variables. The developed modeling and optimization framework is tested by investigating the effect of gene deletions on biomass production and addressing the maximum theoretical production of the 20 amino acids for aerobic growth on glucose and acetate substrates. In the gene deletion study, the smallest gene set necessary to achieve maximum biomass production in E. coli is determined for aerobic growth on glucose. The subsequent gene knockout analysis indicates that biomass production decreases monotonically, rendering the metabolic network incapable of growth after only 18 gene deletions. In the gene addition study, the E. coli flux balance model is augmented with 3,400 non‐E. coli reactions from the KEGG database to form a multispecies model. This model is referred to as the Universal model. This study reveals that the maximum theoretical production of six amino acids could be improved by the addition of only one or two genes to the native amino acid production pathway of E. coli, even though the model could choose from 3,400 foreign reaction candidates. Specifically, manipulation of the arginine production pathway showed the most promise with 8.75% and 9.05% predicted increases with the addition of genes for growth on glucose and acetate, respectively. The mechanism of all suggested enhancements is either by: 1) improving the energy efficiency and/or 2) increasing the carbon conversion efficiency of the production route. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 74: 364–375, 2001.
Learning for sustainable development in tourism networks
Authors: Halme Minna
Published: August 2002

The present study investigates learning toward sustainable development in multi‐stakeholder public–private networks. The evidence is grounded in the data from six tourism networks in four European countries. The process of cooperation appears more important vis‐à‐vis achievements regarding sustainable tourism than the structure of networks. This process will determine the network's ability to become adept at explicating tacit knowledge among its actors, and to develop the network so it can facilitate the creation of sustainability outcomes.

A leading public actor may assume a ‘teacher's’ role in the network. In these instances, the network runs a risk of becoming merely an information dissemination tool. This involves a trap of one‐way communication and under‐used knowledge utilization opportunities. Receptivity of the teacher actor is low and the partners do not really collaborate. The teacher actor should make a special effort to create feedback loops leading to two‐way communication, so that a learning strategy of collaboration can take place. The findings also imply that in some networks with a public leader there is an overly high belief in the ability of information dissemination and classroom education to promote learning about sustainable development although learning about sustainability in the practical level requires concrete results and joint action. Copyright © 2001 John Wiley & Sons, Ltd and ERP Environment
Forensic and correctional applications of the personality assessment inventory
Authors: Edens John F. , Cruise Keith R. , Buffington‐Vollum Jacqueline K.
Published: August 2002

The relative utility of psychological tests for addressing legal issues is an area of considerable debate in the field. Regardless of the merits of psychological testing, it is apparent that such instruments are used widely both to address specific psycholegal issues and to evaluate offender populations more generally. One instrument gaining prominence in terms of its use in both forensic and correctional settings is the Personality Assessment Inventory (PAI; Morey, 1991), which was developed to assess various constructs relevant to clinical settings (e.g. psychopathology, response distortion, and personality traits). This paper reviews the psychometric properties of the PAI specifically in reference to its ability to assess factors relevant to forensic decision‐making, as well as its utility to provide clinically relevant information about offender populations more generally. Copyright © 2001 John Wiley & Sons, Ltd.