bluuebunny/crossref_metadata_2025 huggingface dataset:
Controllable radical copolymerization of styrene and methyl methacrylate using 1,1,2,2‐tetraphenyl‐1,2‐bis(trimethylsilyloxy) ethane as initiator
Authors: Guo Zhenrong , Yang Genjin , Wan Decheng , Huang Junlian
Published: August 2002

Copolymerization of styrene (St) and methyl methacrylate (MMA) was carried out using 1,1,2,2‐tetraphenyl‐1,2‐bis (trimethylsilyloxy) ethane (TPSE) as initiator; the copolymerization proceeded via a “living” radical mechanism and the polymer molecular weight (Mw) increased with the conversion and polymerization time. The reactivity ratios for TPSE and azobisisobutyronitrile (AIBN) systems calculated by Finemann–Ross method were rSt = 0.216 ± 0.003, rMMA= 0.403 ± 0.01 for the former and rSt= 0.52 ± 0.01, rMMA= 0.46 ± 0.01 for the latter, respectively, and the difference between them and the effect of polymerization conditions on copolymerization are discussed. Thermal analysis proved that the copolymers obtained by TPSE system showed higher sequence regularity than that obtained by the AIBN system, and the sequence regularity increased with the content of styrene in copolymer chain segment. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1474–1482, 2001
Photocrosslinking of functionalized rubbers. X. Butadiene–acrylonitrile copolymers
Authors: Decker C. , Nguyen Thi Viet T.
Published: August 2002

The photocrosslinking of polyacrylonitrile‐block‐polybutadiene‐block‐polyacrylonitrile (ABA) was shown to proceed within seconds at ambient temperature upon UV exposure in the presence of an acylphosphine oxide photoinitiator. The curing process was followed by infrared spectroscopy, insolubilization, and hardness measurements. Complete insolubilization could not be achieved with the neat ABA rubber because of the poor reactivity of the 2‐butene double bond and the low vinyl content of the polybutadiene chain. The addition of multifunctional acrylate monomers (20 wt %) causes a substantial increase of both the reaction rate and the crosslink density of the polymer, which becomes completely insoluble in toluene in less than 1 s upon UV irradiation. An even greater effect was observed by using small amounts (1 wt %) of a trifunctional thiol crosslinker. Both the thiol and the photoinitiator concentrations were shown to affect the kinetics of the thiol–ene polymerization and the polymer network crosslink density. A direct relationship was found to exist between the swelling degree of the UV‐cured rubber and the interchain molecular weight of the network. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 2204–2216, 2001
Recent developments in the evaluation technology of fiber and textiles: Toward the engineered design of textile performance
Authors: Kawabata Sueo , Niwa Masako , Yamashita Yoshihiro
Published: August 2002

The engineered design and manufacturing of high‐quality fabrics have been targets of textile technology in this century; however, this has not yet been achieved. There are two reasons for this. One is that a method for the objective evaluation of the primary performance of fabric as clothing material was not established until recently; second, the complex mechanical behavior of the textile fabrics consisting of a fiber assembly has not yet been solved theoretically. The primary performance has been evaluated subjectively by fabric hand judgment. Recent achievement in the objective evaluation technology for fabric hand and other performances of fabric has enabled us to move toward the engineered design of fabric quality. After a brief introduction of the objective method, the “ideal fabric” project, which we are now conducting, is introduced. This project aims at the development of an engineered design of high‐quality suiting with applying the objective evaluation technology. For future development in engineered design technology, we need basic research on the mechanics of textile structures, and on fiber itself. Fibers are the basic material of textiles. The details of fiber property are required for the advanced research of textile mechanics. Recent progress in the single‐fiber measurement technology, we call it “micro‐measurement,” is introduced. Finally, the textile technology in the 21st century is forecasted. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 687–702, 2002
Study on physical properties of blend films from gelatin and polyacrylamide solutions
Authors: Xiao Chaobo , Lu Yongshang , Jing Zhizhong , Zhang Lina
Published: August 2002

Blend films of gelatin and polyacrylamide (PAAm) were prepared by casting the mixed aqueous solutions of both samples in different ratios. All blend films obtained are optically clear to the naked eye. The structure and physical properties of the films were studied by FT‐infrared (FTIR), wide‐angle X‐ray diffraction (WAXD), differential thermal analysis (DTA), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The experimental results show that the blend films exhibit the higher thermal stability and improved mechanical properties of both tensile strength and elongation at break in dry states, which suggests the occurrence of interaction detected by FTIR between gelatin, PAAm, and water molecules in the films. The morphological transition of the blend films from gelatin‐like to PAAm‐like was observed by SEM. Furthermore, moisture content and water swelling property of the blend films were also investigated, which was consistent with the results from SEM. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 949–955, 2002
Structural, electrical, and optical studies of plasma‐polymerized and iodine‐doped poly pyrrole
Authors: John Rajan K. , Kumar D. Sakthi
Published: August 2002

An attempt was made to study the structural, electrical, and optical properties of plasma‐polymerized pyrrole and iodine‐doped pyrrole. A comparative study of the IR spectra of the monomer and polymer pyrrole gives information that the ring structure is retained during plasma polymerization. Iodine doping considerably increases the conductivity of the polymer film and decreases the optical band‐gap energy. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1856–1859, 2002
From college to clinic: Reasoning over memorization is key for understanding anatomy
Authors: Miller Sue Ann , Perrotti William , Silverthorn Dee U. , Dalley Arthur F. , Rarey Kyle E.
Published: August 2002

Anatomy and physiology are taught in community colleges, liberal arts colleges, universities, and medical schools. The goals of the students vary, but educators in these diverse settings agree that success hinges on learning concepts rather than memorizing facts. In this article, educators from across the postsecondary educational spectrum expand on several points: (1) There is a problem with student perception that anatomy is endless memorization, whereas the ability to manage information and use reasoning to solve problems are ways that professionals work. This misperception causes students to approach the subject with the wrong attitude. (2) The process of learning to use information is as important as the concepts themselves. Using understanding to explain and make connections is a more useful long‐term lesson than is memorization. Anatomy should be presented and learned as a dynamic basis for problem solving and for application in the practice and delivery of quality health care. (3) Integration of form and function must be explicit and universal across all systems. (4) Using only models, images, audiovisuals, or computers cannot lead students to the requisite reasoning that comes from investigative dissection of real tissue. (5) Some undergraduate courses require students to memorize excessive musculoskeletal detail. (6) Learning tissue biology is a particular struggle for medical students who have no background from an undergraduate course. (7) Medical professors and students see benefits when students have taken undergraduate courses in anatomy, histology, and physiology. If medical schools suggest these electives to applicants, medical students might arrive better prepared and, thus, be able to learn clinical correlations more efficiently in the limited allocated time of medical school curricula. Anat Rec (New Anat) 269:69–80, 2002. © 2002 Wiley‐Liss, Inc.
Anatomical appraisal of the skulls and teeth associated with the family of Tsar Nicolay Romanov
Authors: Kolesnikov Lev L. , Pashinyan Gurgen A. , Abramov Sergey S.
Published: August 2002

This article describes the identification of skeletal remains attributed to the family of Tsar Nicolay Romanov and other persons buried together at a site near present‐day Ekaterinburg, Russia. Detailed descriptions are given regarding the objective methods of craniofacial and odontological identification that were used. Employing computer‐assisted photographic superimposition techniques and statistical analysis of morphologic and other characteristics of the specimens, this study identifies with a high likelihood of certainty the remains of the Tsar, his wife, three of his four daughters, and four household assistants. Very strong evidence is presented that the Tsar's daughter Anastasia was killed in 1918. This study demonstrates the effectiveness of the methods and trustworthiness of the results, as well as the prospects of future application of the methods for the identification of skeletonized human remains. Anat Rec (New Anat) 265:15–32, 2001. © 2001 Wiley‐Liss, Inc.
From anatomy to the target: Contributions of magnetic resonance imaging to preclinical pharmaceutical research
Authors: Beckmann Nicolau , Mueggler Thomas , Allegrini Peter Roland , Laurent Didier , Rudin Markus
Published: August 2002

In recent years, in vivo magnetic resonance (MR) methods have become established tools in the drug discovery and development process. In this article, the role of MR imaging (MRI) in the preclinical evaluation of drugs in animal models of diseases is illustrated on the basis of selected examples. The individual sections are devoted to applications of anatomic, physiologic, and “molecular” imaging providing, respectively, structural‐morphological, functional, and target‐specific information. The impact of these developments upon clinical drug evaluation is also briefly addressed. The main advantages of MRI are versatility, allowing a comprehensive characterization of a disease state and of the corresponding drug intervention; high spatial resolution; and noninvasiveness, enabling repeated measurements. Successful applications in drug discovery exploit one or several of these aspects. Additionally, MRI is contributing to strengthen the link between preclinical and clinical drug research. Anat Rec (New Anat) 265:85–100, 2001. © 2001 Wiley‐Liss, Inc.
Elevated expression of Nkx‐2.5 in developing myocardial conduction cells
Authors: Thomas Penny S. , Kasahara Hideko , Edmonson Angela M. , Izumo Seigo , Yacoub Magdi H. , Barton Paul J.R. , Gourdie Robert G.
Published: August 2002

A number of different phenotypes emerge from the mesoderm‐derived cardiomyogenic cells of the embryonic tubular heart, including those comprising the cardiac conduction system. The transcriptional regulation of this phenotypic divergence within the cardiomyogenic lineage remains poorly characterized. A relationship between expression of the transcription factor Nkx‐2.5 and patterning to form cardiogenic mesoderm subsequent to gastrulation is well established. Nkx‐2.5 mRNA continues to be expressed in myocardium beyond the looped, tubular heart stage. To investigate the role of Nkx‐2.5 in later development, we have determined the expression pattern of Nkx‐2.5 mRNA by in situ hybridization in embryonic chick, fetal mouse, and human hearts, and of Nkx‐2.5 protein by immunolocalization in the embryonic chick heart. As development progresses, significant nonuniformities emerge in Nkx‐2.5 expression levels. Relative to surrounding force‐generating (“working”) myocardium, elevated Nkx‐2.5 mRNA signal becomes apparent in the specialized cells of the conduction system. Similar differences are found in developing chick, human, and mouse fetal hearts, and nuclear‐localized Nkx‐2.5 protein is prominently expressed in differentiating chick conduction cells relative to adjacent working myocytes. This tissue‐restricted expression of Nkx‐2.5 is transient and correlates with the timing of spatio‐temporal recruitment of cells to the central and the peripheral conduction system. Our data represent the first report of a transcription factor showing a stage‐dependent restriction to different parts of the developing conduction system, and suggest some commonality in this development between birds and mammals. This dynamic pattern of expression is consistent with the hypothesis that Nkx‐2.5, and its level of expression, have a role in regulation and/or maintenance of specialized fate selection by embryonic myocardial cells. Anat Rec 263:307–313, 2001. © 2001 Wiley‐Liss, Inc.
Parasitism of Lacanobia oleracea (lepidoptera) by the ectoparasitic wasp, Eulophus pennicornis, disrupts the cytoskeleton of host haemocytes and suppresses encapsulation in vivo
Authors: Richards Elaine H. , Edwards John P.
Published: August 2002

Parasitism of Lacanobia oleracea larvae by the ectoparasitic wasp Eulophus pennicornis suppressed host haemocyte‐mediated encapsulation of Sephadex DEAE A‐25 beads in vivo. Beads dissected out of parasitized larvae had fewer haemocytes associated with them. Moreover, those haemocytes that were associated with the beads tended to retain a rounded configuration and rarely flattened. Similar results were obtained using in vitro encapsulation assays. SDS PAGE indicated that for parasitized and PBS injected larvae, there were some differences in the plasma proteins that bound to Sephadex DEAE A‐25 beads, suggesting that parasitism‐mediated changes to host plasma proteins might contribute to the differences in the encapsulation response occurring in these larvae. However, in vitro encapsulation assays using beads that had been pre‐incubated in plasma from parasitized and unparasitized larvae, demonstrated that major differences in the extent of encapsulation did not occur. These results, plus in vitro haemocyte attachment and spreading assays, suggest that parasitism‐mediated suppression of encapsulation is primarily due to reductions in the ability of host haemocytes to attach to (i.e., recognize) and flatten over non‐self surfaces and other haemocytes. This proposal is corroborated by staining of actin in the haemocyte cytoskeleton by FITC‐labelled phalloidin, which indicated that parasitism disrupts the formation of stress fibers and focal adhesions in plasmatocytes. By contrast, experimental injection of adult female wasp venom into unparasitized L. oleracea larvae had no significant effect on in vivo encapsulation responses or the haemocyte cytoskeleton. Arch. Insect Biochem. Physiol. 49:108–124, 2002. Published 2002 Wiley‐Liss, Inc.
Involvement of CD4+,CD57+ T cells in the disease activity of rheumatoid arthritis
Authors: Maeda Takeshi , Yamada Hisakata , Nagamine Ryuji , Shuto Toshihide , Nakashima Yasuharu , Hirata Go , Iwamoto Yukihide
Published: August 2002

Objective

To evaluate the relationship between the frequency of peripheral CD57+ T cells and the physical status of rheumatoid arthritis (RA) patients, and to perform cytokine analysis of these CD57+ T cells.

Methods

Four‐color fluorescence‐activated cell sorter analysis was performed to detect both cell surface antigens and intracellular cytokines in peripheral blood leukocytes, using monoclonal antibodies against CD3, CD4, CD8, CD57, interferon‐γ (IFNγ), and interleukin‐4 (IL‐4). RA patients were clinically evaluated with a modified Health Assessment Questionnaire (M‐HAQ), joint score, face scale, and visual analog scale (VAS) assessing pain and disease activity.

Results

There was a significant correlation between the frequency of CD4+,CD57+ T cells and erythrocyte sedimentation rate (ESR), whereas a correlation was not found between the frequency of CD8+,CD57+ T cells and ESR. The frequency of CD4+,CD57+ T cells also showed a significant correlation with the mHAQ score, VAS, and face scale. Again, there was no significant correlation between the above‐mentioned clinical scores and the frequency of CD8+,CD57+ T cells. Flow cytometric analysis of intracellular cytokines revealed that 14.5% of the CD57+ T cells produced IFNγ, whereas only 2.8% of the CD57+ T cells produced IL‐4 in RA patients.

Conclusion

Evidence showing that the frequency of CD4+,CD57+ T cells among CD3+ cells of RA patients had a significant correlation not only with ESR but also with the physical status of the patients, and that a large proportion of the CD4+,CD57+ T cells had the capacity to produce IFNγ, strongly suggests that these CD4+,CD57+ T cells are involved in the immunopathogenesis of RA.
The prevalence and impact of managed care for persons with rheumatoid arthritis in 1994 and 1999
Authors: Yelin Edward , Trupin Laura , Katz Patricia
Published: August 2002

Objectives

To estimate the proportion of persons with rheumatoid arthritis (RA) in managed care and fee‐for‐service settings in 1994 and 1999, to ascertain whether there are differences in utilization between persons in the 2 systems of care in the 2 years, and to determine whether 1994 managed care status or change between 1994 and 1999 in managed care status affects outcomes.

Methods

The present study uses data from the University of California, San Francisco RA Panel Study, in which 310 patients with RA from a random sample of Northern California rheumatologists were interviewed annually between 1994 and 1999 using a structured survey instrument. We use linear and logistic regression to compare the health care utilization and outcomes of persons in managed care and fee‐for‐service after adjusting for differences in demographic and health characteristics.

Results

The proportion of respondents in managed care increased from 60% to 79% between 1994 and 1999, including an increase from 37% to 68% among persons eligible for Medicare and an increase from 74% to 92% among persons ineligible for Medicare. With the exception of physical therapy visits in 1999, patients with RA in managed care did not report significantly different utilization of any service for RA than those in fee‐for‐service in either 1994 and 1999, including hospital admissions and joint replacement surgery. Managed care status in 1994, and change in managed care status between 1994 and 1999, were not associated with significantly different outcomes in 1999.

Conclusion

Despite the growth in the proportion of patients with RA in managed care, those in managed care did not differ from those in fee‐for‐service settings in utilization or outcomes.
A new model that generates Lotka's law
Authors: Huber John C.
Published: August 2002

In this paper, we develop a new model for a process that generates Lotka's Law. We show that four relatively mild assumptions create a process that fits five different informetric distributions: rate of production, career duration, randomness, and Poisson distribution over time, as well as Lotka's Law. By simulation, we obtain good fits to three empirical samples that exhibit the extreme range of the observed parameters. The overall error is 7% or less. An advantage of this model is that the parameters can be linked to observable human factors. That is, the model is not merely descriptive, but also provides insight into the causes of differences between samples. Furthermore, the differences can be tested with powerful statistical tools.
User perspectives on relevance criteria: A comparison among relevant, partially relevant, and not‐relevant judgments
Authors: Maglaughlin Kelly L. , Sonnenwald Diane H.
Published: August 2002

This study investigates the use of criteria to assess relevant, partially relevant, and not‐relevant documents. Study participants identified passages within 20 document representations that they used to make relevance judgments; judged each document representation as a whole to be relevant, partially relevant, or not relevant to their information need; and explained their decisions in an interview. Analysis revealed 29 criteria, discussed positively and negatively, that were used by the participants when selecting passages that contributed or detracted from a document's relevance. These criteria can be grouped into six categories: abstract (e.g., citability, informativeness), author (e.g., novelty, discipline, affiliation, perceived status), content (e.g., accuracy/validity, background, novelty, contrast, depth/scope, domain, citations, links, relevant to other interests, rarity, subject matter, thought catalyst), full text (e.g., audience, novelty, type, possible content, utility), journal/publisher (e.g., novelty, main focus, perceived quality), and personal (e.g., competition, time requirements). Results further indicate that multiple criteria are used when making relevant, partially relevant, and not‐relevant judgments, and that most criteria can have either a positive or negative contribution to the relevance of a document. The criteria most frequently mentioned by study participants were content, followed by criteria characterizing the full text document. These findings may have implications for relevance feedback in information retrieval systems, suggesting that systems accept and utilize multiple positive and negative relevance criteria from users. Systems designers may want to focus on supporting content criteria followed by full text criteria as these may provide the greatest cost benefit.
A view to the future of the library and information science profession: A Delphi study
Authors: Baruchson‐Arbib Shifra , Bronstein Jenny
Published: August 2002

A Delphi study conducted in Israel during 1998–2000 examined the views of library and information science (LIS) experts on the future of the profession in light of the changes in information technology. The study focused on three areas: (a) the transition from the traditional to the virtual library; (b) the transition from the technical to user‐centered approach, and( c) the skills and the roles of the LIS professionals. The study found that most experts believe that the traditional library will continue to operate along with the virtual library. Most of the experts agree that in the future, libraries will place larger emphasis on customer services. LIS professionals will be specialists in locating, filtering, and evaluating information, and will be primary instructors in the use of new information technologies. This study's conclusions closely match those of the Kaliper project (1998–2000), which examined the change in the curricula of LIS schools.
A comparison of methods of approximations for probabilities of death for fractions of a year
Authors: Jasiulewicz Helena
Published: August 2002

In this paper, a comparison of methods of approximating probabilities of death over fractions of a year is given. Previous and new methods in actuarial science and demography are considered. As the measure of distance the Kolmogorov statistic and L2 are taken. The analysis was carried out using real data. Copyright © 2001 John Wiley & Sons, Ltd.
Stereoselective pharmacokinetics of desbutylhalofantrine, a metabolite of halofantrine, in the rat after administration of the racemic metabolite or parent drug
Authors: Brocks Dion R.
Published: August 2002

The main objective of this study was to determine the pharmacokinetics of the enantiomers of desbutylhalofantrine (DHF), a metabolite of halofantrine (HF), in the rat. Rats received either intravenous (2 mg/kg) or oral (7 mg/kg) (±)‐DHF HCl, or (±)‐HF HCl intravenously (3 mg/kg). Enantiomer concentrations in plasma were determined by a stereospecific assay. In all rats, the plasma concentrations of (+)‐DHF exceeded those of (−)‐DHF. After (±)‐DHF, the mean (+):(−) ratios of AUC0–∞ after oral and intravenous dosing were 3.7 and 2.8, respectively. After intravenous doses of DHF, the (−):(+) enantiomeric ratios of Cl and Vdss were approximately 2.8. There were no significant differences between the enantiomers in t1/2 (mean 14–23 h) or tmax (mean 10–12 h) after intravenous or oral administration of DHF. Oral bioavailability estimates of DHF enantiomers (>59%) were higher than those previously estimated for HF in the rat. The stereoselectivity in HF kinetics was not as pronounced as for DHF. It was estimated that over 44% of the dose of HF is metabolized to DHF enantiomers. It was concluded that DHF possesses a pharmacokinetic profile similar to that of HF, each possessing low values of clearance and high volume of distribution. DHF differed from HF in its degree of stereoselectivity in pharmacokinetics, and in its extent of oral bioavailability. Copyright © 2000 John Wiley & Sons, Ltd.
Complete bioavailability and lack of food‐effect on pharmacokinetics of gliclazide 30 mg modified release in healthy volunteers
Authors: Delrat P. , Paraire M. , Jochemsen R.
Published: August 2002

A new modified release (MR) formulation containing 30 mg of gliclazide was developed to obtain a better predictable release of the active principle and to allow once‐daily dosing regimen. An absolute bioavailability study was carried out to characterise the performance of the new formulation and the food‐effect was also investigated in a separate study. Both studies were single dose, randomised, open label, two way cross over studies with a wash out period between doses. For the bioavailability study, each volunteer received 30 mg of gliclazide given either as a 1 h intravenous infusion or as a 30 mg MR tablet. For the food‐effect study, the treatment was given either fasted or 10 min after the start of a standardised Melander breakfast. Blood samples were collected up to 72 h after administrations and plasma samples assayed for gliclazide concentrations using a reverse‐phase HPLC method with UV detection. Mean absolute bioavailability of gliclazide was 97% and ranged between 79 and 110% showing complete absorption. A similar moderate to low variability was observed after IV and oral administration showing the MR formulation did not add to the overall variability which is solely due to the disposition parameters, in particular metabolism of gliclazide. No significant difference was observed in tmax, t1/2z, Cmax and AUC of gliclazide after administration of the 30 mg MR tablet under fasted and fed conditions. In conclusion, after single oral administration of a 30 mg MR tablet, gliclazide was completely absorbed both under fasted and fed conditions. A consistent and optimal release of gliclazide from this formulation leads to a low to moderate overall variability of its pharmacokinetic parameters. Diamicron 30 mg MR can be given without regards to meals i.e. before, during or after breakfast. Copyright © 2002 John Wiley & Sons, Ltd.
Effect of magnetic field exposure on calcium channel currents using patch clamp technique
Authors: Obo Mayumi , Konishi Shiro , Otaka Yoshihisa , Kitamura Satoshi
Published: August 2002

Calcium influxes through the membrane of PC‐12D cells were measured under exposure to DC biased AC magnetic fields in resonant conditions of the ion cyclotron and the ion parametric resonance hypotheses and compared with influxes in cells without exposure to the magnetic field. After cancellation of the geomagnetic field, the cells were exposed to the horizontal fields generated by a current sheet, a planar sheet of conductor which generated a satisfactorily homogeneous horizontal magnetic field on the stage of a microscope without hindering treatment of a cell under observation. At or near any resonant conditions, no change in calcium influx could be detected under standard patch clamp conditions. Bioelectromagnetics 23:306–314, 2002. © 2002 Wiley‐Liss, Inc.
Magnetic field exposure and behavioral monitoring system
Authors: Thomas A.W. , Drost D.J. , Prato F.S.
Published: August 2002

To maximize the availability and usefulness of a small magnetic field exposure laboratory, we designed a magnetic field exposure system that has been used to test human subjects, caged or confined animals, and cell cultures. The magnetic field exposure system consists of three orthogonal pairs of coils 2 m square × 1 m separation, 1.751 m × 0.875 m separation, and 1.5 m × 0.75 m separation. Each coil consisted of ten turns of insulated 8 gauge stranded copper conductor. Each of the pairs were driven by a constant‐current amplifier via digital to analog (D/A) converter. A 9 pole zero‐gain active Bessel low‐pass filter (1 kHz corner frequency) before the amplifier input attenuated the expected high frequencies generated by the D/A conversion. The magnetic field was monitored with a 3D fluxgate magnetometer (0–3 kHz, ± 1 mT) through an analog to digital converter. Behavioral monitoring utilized two monochrome video cameras (viewing the coil center vertically and horizontally), both of which could be video recorded and real‐time digitally Moving Picture Experts Group (MPEG) encoded to CD‐ROM. Human postural sway (standing balance) was monitored with a 3D forceplate mounted on the floor, connected to an analog to digital converter. Lighting was provided by 12 offset overhead dimmable fluorescent track lights and monitored using a digitally connected spectroradiometer. The dc resistance, inductance of each coil pair connected in series were 1.5 m coil (0.27 Ω, 1.2 mH), 1.75 m coil (0.32 Ω, 1.4 mH), and 2 m coil (0.38 Ω, 1.6 mH). The frequency response of the 1.5 m coil set was 500 Hz at ± 463 μT, 1 kHz at ± 232 μT, 150 μs rise time from −200 μTpk to + 200 μTpk (square wave) and is limited by the maximum voltage ( ± 146 V) of the amplifier (Bessel filter bypassed). Bioelectromagnetics 22:401–407, 2001. © 2001 Wiley‐Liss, Inc.
ELF magnetic field inhibits gap junctional intercellular communication and induces hyperphosphorylation of connexin43 in NIH3T3 cells
Authors: Hu G.L. , Chiang H. , Zeng Q.L. , Fu Y.D.
Published: August 2002

The effects of extremely low frequency (ELF) magnetic field on gap junctional intercellular communication (GJIC), protein levels, and phosphorylation of connexin43 (Cx43) were studied in NIH3T3 cells. The suppression of GJIC by 24 h, 50 Hz, 0.8 mT ELF magnetic field, 2 h, 3 ng/ml 12‐O‐tetradecanoylphorbol‐13‐acetate (TPA), or ELF combined with TPA treatment was confirmed by the fluorescence recovery after photobleaching (FRAP) analysis with a confocal microscope. The results showed that ELF or TPA exposure induced 50–60% inhibition of GJIC (P < 0.01). ELF combined with TPA enhanced the inhibition of GJIC. Western blot analysis using Cx43 specific antibodies showed obviously decreasing non phosphorylated Cx43 (P0) induced by ELF and/or TPA exposure. On the other hand, cells treated with ELF and/or TPA displayed a hyperphosphorylated Cx43 band (P3). However, there was no obvious changes in the level of Cx43 protein. The results implied that the P3 band appeared to result from phosphorylation of P0. But it remains possible that upon the ELF exposure P0 is converted to P1, P2 or both and that P3 is formed from P1 or P2 resulting in the observed hyperphosphorylation pattern. From the present study, we conclude that ELF magnetic field inhibits GJIC and the main mechanism is the hyperphosphorylation of Cx43. Bioelectromagnetics 22:568–573, 2001. © 2001 Wiley‐Liss, Inc.
Influence of a stationary magnetic field on water relations in lettuce seeds. Part I: Theoretical considerations
Authors: Reina Francisco Garcìa , Pascual Luis Arza
Published: August 2002

The theoretical calculation about the dependence of the ionic current density across the cellular membrane on the intensity of the magnetic field applied to cellular tissue is presented. This interaction induces changes in the magnitude of the ionic current density across the cellular membrane and in the ionic concentration, and it also causes alterations in the osmotic pressure and in the capacity of the cellular tissues to absorb water. The magnetic field dependence of the ionic current densities Jp (B) (positive ions) and Jn (B) (negative ions), the membrane conductivity σ (B), the ionic concentration in both membrane sides c(B), the osmotic pressure π (B), and the water uptake rate by seeds kw (B) are presented. The increase in water uptake rate due to the applied magnetic field may be the explanation of the recently reported increase in the germination speed of the seeds treated with stationary magnetic fields. Bioelectromagnetics 22:589–595, 2001. © 2001 Wiley‐Liss, Inc.
Bacterial ion channels and their eukaryotic homologues
Authors: Koprowski Piotr , Kubalski Andrzej
Published: August 2002

Due to the relative ease of obtaining their crystal structures, bacterial ion channels provide a unique opportunity to analyse structure and function of their eukaryotic homologues. This review describes prokaryotic channels whose structures have been determined. These channels are KcsA, a bacterial homologue of eukaryotic potassium channels, MscL, a bacterial mechanosensitive ion channel and ClC0, a prokaryotic homologue of the eukaryotic ClC family of anion‐selective channels. General features of their structure and function are described with a special emphasis on the advantages that these channels offer for understanding the properties of their eukaryotic homologues. We present amino‐acid sequences of eukaryotic proteins related in their primary sequences to bacterial mechanosensitive channels. The usefulness of bacterial mechanosensitive channels for the studies on general principles of mechanosensation is discussed. BioEssays 23:1148–1158, 2001. © 2001 John Wiley & Sons, Inc.
Comparative insect developmental genetics: phenotypes without mutants
Authors: Denell Rob , Shippy Teresa
Published: August 2002

The last decade has seen a dramatic increase in interest in the extent to which morphological evolution depends on changes in regulatory pathways. Insects provide a fertile ground for study because of their diversity and our high level of understanding of the genetic regulation of development in Drosophila melanogaster. However, comparable genetic approaches are presently possible in only a small number of non‐Drosophilid insects. In a recent paper, Hughes and Kaufman(1) have used a new methodology, RNA interference, in the milkweed bug, Oncopeltus fasciatus, to phenocopy the effects of mutations in Hox genes. RNA interference involves the injection of double‐stranded RNA of the same sequence as the relevant mRNA resulting in a depletion of that transcript.(2) Hughes and Kaufman focused on the gnathal segments, which elaborate specialized appendages important to feeding. Their results indicate that gnathal adaptations in this bug are correlated with changes in Hox gene functions and interactions. BioEssays 23:379–382, 2001. © 2001 John Wiley & Sons, Inc.
Evolutionary history of vertebrate appendicular muscle
Authors: Galis Frietson
Published: August 2002

The evolutionary history of muscle development in the paired fins of teleost fish and the limbs of tetrapod vertebrates is still, to a large extent, uncertain. There has been a consensus, however, that in the vertebrate clade the ancestral mechanism of fin and limb muscle development involves the extension of epithelial tissues from the somite into the fin/limb bud. This mechanism has been documented in chondrichthyan, dipnoan, chondrostean and teleost fishes. It has also been assumed that in amniotes, in contrast, individual progenitor cells of muscles migrate from the somites into the limb buds. Neyt et al.(1) now present the exciting finding that in zebrafishes this presumably derived mechanism involving individual cell migration, is present. They conclude, based on data on sharks, zebrafishes, chickens, quails and mice that the derived mechanism was present in the sarcopterygians. This conclusion, however, may be premature in the light of further data available in the literature, which show a highly mosaic distribution of this character in the vertebrate clade. Furthermore, a developmental mode exists that is intermediate between the supposed ancestral and derived modes in teleosts, reptiles and possibly amphibians. BioEssays 23:383–387, 2001. © 2001 John Wiley & Sons, Inc.
A plausible function of the prion protein: conjectures and a hypothesis
Authors: Abdulla Yousef H.
Published: August 2002

Amyloid beta precursor protein (APP) and prion protein (PrP) are cell membrane elements implicated in neurodegenerative diseases. Both proteins undergo endoproteolysis. Evidence is adduced from the literature hinting that the process in the two proteins could be related, their functions may overlap and their distributions coincide. It is proposed that PrP catalyses its own cleavage, the C‐terminal fragment functions as an α secretase and the N‐terminal segment chaperones the active site; the α secretase releases anticoagulant and neurotrophic ectodomains from APP. The proposals explain some features of spongiform encephalopathies. BioEssays 23:456–462, 2001. © 2001 John Wiley & Sons, Inc.
Mitochondria in the pathogenesis of lipodystrophy induced by anti‐HIV antiretroviral drugs: actors or bystanders?
Authors: Cossarizza Andrea , Mussini Cristina , Viganò Alessandra
Published: August 2002

Effective therapies are now available that can stop the progression of HIV infection and significantly delay the onset of AIDS. The “highly active antiretroviral therapy” (HAART) is a combination of potent antiretroviral drugs such as viral protease inhibitors or nucleoside‐analogue reverse‐transcriptase inhibitors, that has a variety of serious side effects, including lipodystrophy, a pathology characterized by accumulation of visceral fat, breast adiposity, cervical fat‐pads, hyperlipidemia, insulin resistance as well as fat wasting in face and limbs. There is still an open debate that concerns the precise responsibility of HAART as well as metabolic pathways and mechanisms that are involved in the onset of lipodystrophy. The similarities with multiple symmetric lipomatosis (MSL), in which mitochondria impairment plays a crucial role, lead to the hypothesis that drug‐induced damages to mitochondrial DNA are able to alter mitochondria functionality to an extent that is similar to what occurs in MSL. In addition, several evidences indicate that HAART is also linked to a deregulated production of tumour necrosis factor‐α, which uses mitochondria as intracellular targets. In this paper, we review data concerning the role of mitochondria in the pathogenesis of lipodystrophy, and advance a unifying hypothesis involving either direct or indirect effects of the drugs employed during HAART. BioEssays 23:1070–1080, 2001. © 2001 John Wiley & Sons, Inc.
Functional assessment and treatment of pica: a single‐case experiment
Authors: Rapp John T. , Dozier Claudia L. , Carr James E.
Published: August 2002

The pica of a 6‐year‐old girl diagnosed with autism was initially shown to persist in the absence of socially mediated consequences. In an attempt to provide a competing source of oral stimulation, we used a stimulus preference assessment to identify food items that were subsequently presented noncontingently. However, the noncontingent schedule could not be thinned to a practical variation while still maintaining reductions in pica. A subsequent multielement evaluation of response blocking and verbal reprimands demonstrated that neither intervention both produced and maintained low levels of pica. Verbal reprimands were then used in conjunction with noncontingent food presentation, but this intervention did not produce significant reductions in pica. Suppression of pica was ultimately obtained in both a clinic setting and in the child's natural environment using contingent, varied auditory stimulation. The results are discussed in the context of the ‘least restrictive alternative’ model of treatment selection. Copyright © 2001 John Wiley & Sons, Ltd.
Recognizing shorter coding regions of human genes based on the statistics of stop codons
Authors: Wang Yonghong , Zhang Chun‐Ting , Dong Puxuan
Published: August 2002

With the quick progress of the Human Genome Project, a great amount of uncharacterized DNA sequences needs to be annotated copiously by better algorithms. Recognizing shorter coding sequences of human genes is one of the most important problems in gene recognition, which is not yet completely solved. This paper is devoted to solving the issue using a new method. The distributions of the three stop codons, i.e., TAA, TAG and TGA, in three phases along coding, noncoding, and intergenic sequences are studied in detail. Using the obtained distributions and other coding measures, a new algorithm for the recognition of shorter coding sequences of human genes is developed. The accuracy of the algorithm is tested based on a larger database of human genes. It is found that the average accuracy achieved is as high as 92.1% for the sequences with length of 192 base pairs, which is confirmed by sixfold cross‐validation tests. It is hoped that by incorporating the present method with some existing algorithms, the accuracy for identifying human genes from unannotated sequences would be increased. © 2002 John Wiley & Sons, Inc. Biopolymers 63: 207–216, 2002
Structural features of two distinct molecular complexes of copper(II) cationic porphyrin and deoxyribonucleotides
Authors: Mojzes Peter , Praus Petr , Baumruk Vladimir , Turpin Pierre‐Yves , Matousek Pavel , Towrie Michael
Published: August 2002

The associations of the water‐soluble cationic copper(II)‐5,10,15,20‐meso‐tetrakis(4‐N‐methylpyridyl) porphyrin (CuP) with d(pT)9 oligothymidylate and its building blocks deoxythymidine (dT) and deoxythymidine 5′‐monophosphate (dTMP) were investigated by spectrophotometric titration [absorption, nanosecond transient resonance Raman (ns‐RR) and picosecond time‐resolved resonance Raman (ps‐TR3) spectroscopies] to elucidate the structural requirements for the CuP exciplex formation in molecular complexes with unchained mononucleotides. In the d(pT)9 a factor analysis and global fit of the CuP absorption spectra revealed the formation of a single spectral species attributable to a 1 : 1 CuP · d(pT)9 complex throughout a wide range of d(pT)9/CuP ratios (0–10). Using ps‐TR3 spectroscopy, the CuP · d(pT)9 complex was shown to be fully responsible for exciplex formation. In contrast, CuP mixed with dTMP ([dTMP]/[CuP] < 3000) yielded two spectroscopically distinct types of molecular complexes with 1 : 1 (CuP · dTMP) and 1 : 2 (CuP · (dTMP)2) (or even higher for [dTMP]/[CuP] > 3000) stoichiometry, the latter being spectroscopically identical to the CuP · d(pT)9 and providing a microenvironment favorable for exciplex formation to the same extent as the oligothymidylate. On the other hand, the 1 : 1 CuP · dTMP complex (prevailing for [dTMP]/[CuP] < 100) yielded no exciplex features. Similar behavior was observed for the CuP complexed with dT. To explain the difference in the ability of the CuP · dTMP and CuP · (dTMP)2 species to form the exciplex, two types of molecular complexes were suggested and discussed, differing in the orientation of the thymine planes with respect to the porphyrin macrocycle. © 2002 Wiley Periodicals, Inc. Biopolymers (Biospectroscopy) 67: 278–281, 2002
Extreme stability of helices formed by water‐soluble poly‐N‐substituted glycines (polypeptoids) with α‐chiral side chains
Authors: Sanborn Tracy J. , Wu Cindy W. , Zuckermann Ronald N. , Barron Annelise E.
Published: August 2002

Poly‐N‐substituted glycines or “peptoids” are protease‐stable peptide mimics. Although the peptoid backbone is achiral and lacks hydrogen‐bond donors, substitution with α‐chiral side chains can drive the formation of stable helices that give rise to intense CD spectra. To systematically study the solution properties and stability of water‐soluble peptoid helices with α‐chiral side chains, we have synthesized and characterized an amphipathic, 36‐residue N‐substituted glycine oligomer. CD was used to investigate effects of concentration and solvent environment on this helical peptoid. We saw no significant dependence of helical structure on concentration. Intense, “α‐helix‐like” CD spectra were observed for the 36‐mer in aqueous, 2,2,2‐trifluorethanol (TFE), and methanol solution, proving a relative insensitivity of peptoid helical structure to solvent environment. While CD spectra taken in these different solvents were fundamentally similar in shape, we did observe some interesting differences in the intensities of particular CD bands in the various solvents. For example, the addition of TFE to an aqueous solvent increases the degree of peptoid helicity, as is observed for polypeptide α‐helices. Moreover, the helical structure of peptoids appears to be virtually unaffected by heat, even in an aqueous buffer containing 8 M urea. The extraordinary resistance of these peptoid helices to denaturation is consistent with a dominant role of steric forces in their structural stabilization. The structured polypeptoids studied here may have potential as robust mimics of helical polypeptides of therapeutic interest. © 2002 John Wiley & Sons, Inc. Biopolymers 63: 12–20, 2002
Effects of various environmental conditions on the transformation of chlorinated solvents by Methanosarcina thermophila cell exudates
Authors: Baeseman Jenny L. , Novak Paige J.
Published: August 2002

Several microbiologically produced biomolecules have been shown to degrade chlorinated contaminants found in groundwater systems. It was discovered that the cell‐free exudates of the methanogen Methanosarcina thermophila were capable of carbon tetrachloride (CT) and chloroform (CF) degradation. Characterization of the exudates suggested that the active agents were porphorinogen‐type molecules, possibly containing zinc. This research was performed to determine if the exudates from M. thermophila could be used for remediation purposes. The cell exudates were found to be capable of degrading CT, CF, tetrachloroethene, trichloroethene, and 1,1,1‐trichloroethane. CT degradation was used to gauge exudate activity under a variety of conditions that would be encountered in the environment. The cell exudates were active when incubated in two types of soil matrices and at temperatures ranging from 4 to 23°C. Over a 35‐day period approximately 10.2 μmoles of CT were degraded by M. thermophila exudates. To test the hypothesis that the exudates contained either a zinc porphorinogen or a quinone, experiments were performed with zinc 5,10,15,20‐tetra (4‐pyridyl)‐21 H, 23 H‐porphine tetrakis, protoporphyrin IX zinc, and juglone. The two zinc porphyrins were capable of mediating CT degradation at rates comparable to those observed with the M. thermophila exudates; however, juglone was only capable of very slow CT transformation. The electron‐transfer activity of the M. thermophila cell exudates was therefore more consistent with the activity of porphorinogens rather than quinones. Finally, in two enrichment cultures established from aquifer material and marine sediment, the possibility of excreted agents capable of degrading CT was evident. © 2001 John Wiley & Sons, Inc. Biotechnol Bioeng 75: 634–641, 2001.