bluuebunny/crossref_metadata_2025 huggingface dataset:
Positron annihilation and differential scanning calorimetry studies of polyacrylamide and poly(dimethylacrylamide)/poly(ethylene glycol) blends
Authors: Ribeiro E Silva M. E. S. , Machado J. Caetano , Mano V. , Silva G. Goulart
Published: June 2003

Positron annihilation lifetime spectroscopy and differential scanning calorimetry (DSC) measurements were performed for blends of polyacrylamide (PAM) and poly(ethylene glycol) (PEG) and blends of poly(dimethylacrylamide) (PDMAM) and PEG. The samples were prepared by codissolution in a concentration range of 0–100 wt % PEG. The thermal behavior, characterized by DSC measurements, showed similar variations of the glass‐transition temperatures (Tg's) with the PEG concentration for the two systems. Pure PAM and PDMAM presented Tg's of 188 and 111 °C, respectively. A relatively small and nearly linearly decreasing Tg was observed for the two systems in the range of 20–80 wt % PEG. PEG crystals were present in all blend compositions, and no melting point depression was observed. The thermal results pointed to the partial miscibility of the blends. The degree of crystallinity of PEG increased with increasing PEG concentration for the PDMAM/PEG systems. The ortho‐positronium lifetime (τ3) increased with increasing PEG concentration for both blends. However, the parameter of the ortho‐positronium formation probability (I3) decreased with the PEG concentration. The product τI3, which was proportional to the total free volume fraction, was approximately constant with the PEG concentration for PDMAM blends and increased with the PEG concentration for PAM systems. This result may be interpreted as a consequence of a more heterogeneous structure in PAM blends. Scanning electron microscopy micrographs of blends with 40 and 80 wt % PEG provided evidence of the regions associated with PEG crystallites. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 1493–1500, 2003
Melt‐processable blends of ionic poly(p‐phenylene terephthalamide) and poly(4‐vinylpyridine): Relaxation behavior
Authors: Chen W. C. , Sauer J. A. , Hara M.
Published: June 2003

Melt‐processable blends were prepared from rigid molecules of an ionically modified poly(p‐phenylene terephthalamide) (PPTA) and flexible‐coil molecules of poly(4‐vinylpyridine) (PVP). Dynamic mechanical analyses of blends with 50% or more of the ionic PPTA component revealed the presence of two distinct phases. The glass‐transition temperature of the more stable, ionic PPTA‐rich phase increased linearly with the ionic PPTA content. The second phase present in these blends was an ionic PPTA‐poor, or a PVP‐rich, phase. For this phase, a reasonably good fit of the data, showing the glass‐transition temperature as a function of the ionic PPTA content, was achieved between the results of this study and the reported results of previous investigation of molecular composites of the same two components with ionic PPTA contents of 15 wt % or less. The possible influence of annealing on the blend structure of a 90/10 blend of ionic PPTA and PVP was examined. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 1468–1475, 2003
Numerical and experimental analysis of the plasma in the synthesis of polyaniline
Authors: Olayo M. G. , Morales J. , Cruz G. J. , Barocio S. R. , Olayo R.
Published: June 2003

A numerical and experimental study of the plasma variables in the synthesis of polyaniline in radio‐frequency (RF) glow discharges is presented. The plasma variables were measured on the basis of data collected by electrostatic Langmuir probes placed along the reactor. The results showed the distribution of the electric potential and the electronic energy and density during the polymerization reactions. The region with the lowest energy was the zone adjoining the grounded electrode, whereas the maximum energy was located near the RF electrode. In the second zone, the energy was around twice that of the grounded zone, and both were beyond the typical atomic bonding energy found in most organic polymers. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 1501–1508, 2003
Properties of epoxy networks derived from the reaction of diglycidyl ether of bisphenol A with polyhedral oligomeric silsesquioxanes bearing OH‐functionalized organic substituents
Authors: Pellice S. A. , Fasce D. P. , Williams R. J. J.
Published: June 2003

A polyhedral oligomeric silsesquioxane (POSS), consisting mainly of a mixture of octahedra, nonahedra, and decahedra with bulky and flexible organic substituents, with three secondary hydroxyls per organic group, was used to modify epoxy networks produced by the homopolymerization of diglycidyl ether of bisphenol A in the presence of benzyldimethylamine. Several physical, thermal, and mechanical properties of the cured materials containing 0, 10, 30, and 50 wt % POSS were determined. The addition of POSS increased the elastic modulus and the yield stress measured in uniaxial compression tests, mainly because of the increase in the cohesive energy density produced by hydrogen bonding through the hydroxyl groups. A constant yield stress/elastic modulus ratio equal to 0.03 was observed for different POSS concentrations and test temperatures. The glass‐transition temperature decreased with POSS addition because of the flexibility of organic branches present in the POSS structure and the decrease in the crosslink density (determined from the rubbery modulus). Although a combination of a reduction in the glass‐transition temperature (plasticization) with an increase in the glassy modulus (antiplasticization) is a well‐known phenomenon, what is original is that in this case it was not the result of the suppression (or reduction in intensity) of subglass relaxations but was produced by an increase in the cohesive energy density. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 1451–1461, 2003
Radiooxidation of fluoropolymers: Identification of oxidation products
Authors: Boullier I. , Esnouf S. , Moël A. Le
Published: June 2003

Radiation effects on fluoropolymers induced by high‐energy irradiation were investigated. Poly(fluorovinylidene‐co‐hexafluoropropylene) [P(VDF‐HFP)] films were irradiated with γ rays in air. Peroxy radicals formed by irradiation in the presence of oxygen were partially converted into more stable products such as hydroperoxides, alcohols, and acids. These oxidation products were identified by Fourier transform infrared spectroscopy. Specific chemical treatments were carried out to identify and separate overlapping absorption bands. Model compounds were also used. On the basis of the results, a mechanism of degradation for γ‐irradiated P(VDF‐HFP) is proposed. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 1509–1517, 2003
States of water in poly(vinyl alcohol) derivative hydrogels
Authors: Ruiz J. , Mantecón A. , Cádiz V.
Published: June 2003

We studied the behavior of absorbed water in equilibrium‐swollen poly(vinyl alcohol) derivative hydrogels by differential scanning calorimetry (DSC), 1H nuclear magnetic resonance, and wide‐angle X‐ray diffraction. By DSC, three types of water were detected, and their relative fractions were estimated. With this technique we also calculated the pore size for every sample. From the nonexponential decay of the spin–spin relaxation data, we distinguished two environmental states of the absorbed water in the samples. The relaxation times were determined. From these data, we calculated the fractions of each type of water for every hydrogel and related them to the degree of crosslinking. The X‐ray study indicated that the water absorbed in these hydrogels forms a single crystalline phase on cooling. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 1462–1467, 2003
CO2‐delayed crystallization of isotactic polypropylene: A kinetic study
Authors: Zhang Zhiyi , Nawaby A. Victoria , Day Michael
Published: June 2003

The effect of CO2 on the nonisothermal crystallization of isotactic polypropylene (iPP) was studied with high‐pressure differential scanning calorimetry at cooling rates of 0.2–5 °C/min. CO2 significantly delayed the melt crystallization of iPP, and both the crystallization temperature and the heat of crystallization decreased with increasing CO2 pressure. The crystallization rate of iPP, as characterized by the half‐time, was also prolonged by the presence of CO2. With a modified Ozawa model developed by Seo, the Avrami crystallization exponent n of iPP was calculated. This value was depressed by the addition of CO2 and was strongly dependent on the CO2 pressure at low cooling rates. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 1518–1525, 2003
Electrospinning of poly(vinylidene fluoride)/dimethylformamide solutions with carbon nanotubes
Authors: Seoul Chang , Kim Yong‐Tae , Baek Chi‐Kyung
Published: June 2003

For conductive carbon nanotube (CN)/polymer composite fibers to be obtained, CNs were incorporated into poly(vinylidene fluoride) (PVDF) in dimethylformamide (DMF) solutions and electrospun to form CN/PVDF fiber mats. The thinnest fiber was 70 nm thick. The percolation threshold for the insulator‐to‐conductor transition was 0.003 wt % CN for CN/PVDF/DMF solutions, 0.015 wt % CN for CN/PVDF spin‐coated films, and 0.04 wt % CN for CN/PVDF electrospun fiber mats. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 1572–1577, 2003
Fine structure and formation mechanism of particulate phase‐inversion poly(vinylidene fluoride) membranes
Authors: Lin Dar‐Jong , Beltsios Konstantinos , Chang Cheng‐Liang , Cheng Liao‐Ping
Published: June 2003

The structure and formation mechanism of a microporous phase‐inversion poly(vinylidene fluoride) (PVDF) membrane exhibiting a relatively loosely packed agglomerate of semicrystalline globules are explored. The membrane has been prepared by the coagulation of a solution of PVDF in dimethylformamide by the action of 1‐octanol, which is a soft nonsolvent. Experimental observations pertain to the globule surface, which is dominated by a grainy nanostructure; the globular interior, which exhibits a range of fine structures (e.g., twisted sheets and treelike branches); and the globule–globule connections, which exhibit a sheetlike or ropelike structure. On the basis of the observed structural details and phase diagram considerations, it is proposed that the membrane structure is the result of a unique combination of a polymer crystallization and a liquid–liquid phase‐separation process, with end‐result globular structural features of remarkable uniformity. © 2003 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 41: 1578–1588, 2003
Appreciating the beauty of science ideas: Teaching for aesthetic understanding
Authors: Girod Mark , Rau Cheryl , Schepige Adele
Published: June 2003

A large literature exists in which scientists describe their field as beautiful and the work they do as inspiring and passionate. Science teaching should strive to foster learning of substantive and powerful science ideas in ways that connect to the beauty inherent in those ideas. Our conception of learning science, that of learning for aesthetic understanding, achieves this goal by building on a framework of aesthetic experiences proposed by Dewey. This study is an articulation of the major components of aesthetic understanding, pedagogy designed to foster it, and the results of a pilot study designed to investigate its effectiveness. Responses to a survey and a semistructured interview are compared for students in two, fourth grade classrooms. The instructional goals were different in each classroom; one taught for the goal of aesthetic understanding, the second for the goal of conceptual understanding. Survey results indicate that the pedagogical moves were effective in scaffolding aesthetic understanding in treatment class students. More interesting, however, are student reports of the quality of the learning experience in the treatment class. © 2003 Wiley Periodicals, Inc. Sci Ed 87:574–587, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/sce.1054
Confidence intervals for the 50 per cent response dose
Authors: Faraggi D. , Izikson P. , Reiser B.
Published: June 2003

Confidence intervals for the 50 per cent response dose are usually computed using either the Delta method or Fieller's procedure. Recently, confidence intervals computed by inverting the asymptotic likelihood ratio test have also been recommended. There is some controversy as to which of these methods should be used. By means of an extensive simulation study we examine these methods as well as confidence intervals obtained by the approximate bootstrap confidence (ABC) procedure and an adjusted form of the likelihood ratio based confidence intervals. Copyright © 2003 John Wiley & Sons, Ltd.
Assessing the appropriateness of combining economic data from multinational clinical trials
Authors: Cook John R. , Drummond Michael , Glick Henry , Heyse Joseph F.
Published: June 2003

Because of the potential for large variability among countries in the utilization and cost of health care resources, it is important to assess the appropriateness of combining economic data across the countries in a multinational clinical economic trial. We show how available tests for interaction can be applied to economic endpoints, including cost‐effectiveness ratios and net health benefits. This analysis includes a characterization of possible interactions being quantitative or qualitative in nature. In the absence of interaction, a pooled estimate of the economic endpoint should be representative of the participating countries. We explore the analytic issues by further analysing data from the Scandinavian Simvastatin Survival Study (4S). Copyright © 2003 John Wiley & Sons, Ltd.
Model‐driven design of collaborative Web applications
Authors: Matera M. , Maurino A. , Ceri S. , Fraternali P.
Published: June 2003

This paper introduces a model‐driven approach to the design of collaborative Web‐based applications, i.e. applications in which several users play different roles, in a collaborative way, to pursue a specific goal. The paper illustrates a conference management application (CMA), whose main requirements include: (i) the management of users profiles and access rights based on the role played by users during the conference life cycle; (ii) the delivery of information and services to individual users; (iii) the management of the sequence of activities that lead to the achievement of a common goal. The presented approach is based on WebML, a conceptual modelling language for the Web. The paper also highlights some general properties—as understood by the practical experience of CMA development—that a Web modelling language should feature in order to fully support the development of collaborative applications. Copyright © 2003 John Wiley & Sons, Ltd.
Spreadsheet method for temperature calculation of unprotected steelwork subject to fire
Authors: Wong M. B. , Ghojel J. I.
Published: June 2003

The determination of fire resistance level of a structural member in a building requires an efficient and accurate assessment of its limiting temperature in an enclosure fire environment. A significant discrepancy in the results of calculation of the limiting temperature could lead to an increase in the size of the structural member or an increase in the thickness of the fire protection materials. In either case, the cost of construction may increase. This paper introduces an efficient and accurate method for temperature prediction of steel members under four‐sided fire exposure conditions. The method is based on the heat transfer principles commonly adopted in current codes of practice. However, the proposed method emphasizes the effect of gaseous composition of the combustion products on the evaluation of heat transfer coefficients that most codes of practice ignore. In addition, the complex forms of heat transfer coefficients have been simplified for practical use while the accuracy is still maintained. This method is well suited for practising engineers performing structural design for fire as the calculation procedure can be carried out entirely on a spreadsheet. Copyright © 2003 John Wiley & Sons, Ltd.
Effect of creep and shrinkage in reinforced concrete frame–shear wall system with high beam stiffness
Authors: Maru Savita , Sharma R. K. , Nagpal A. K.
Published: June 2003

The behaviour of frames and frame–shear wall systems with regard to creep and shrinkage with high beam stiffness has been largely unexplored until recently since no procedure has been available. For low beam stiffness the most widely used procedure available in literature for determining creep and shrinkage effects in reinforced concrete building frames and frame–shear wall systems designated herein as approximate procedure, AP has been recommended for buildings having flexible slab systems and with a limited number of storeys. Recently an accurate procedure termed Consistent Procedure (CP) has been developed which is applicable to low as well as high beam stiffness and requires no restriction on number of storeys. In this paper, using CP, studies are reported for frame–shear wall systems with high beam stiffness. The effect of introduction of shear walls on load transfer among vertical members considering creep and shrinkage is studied. It is shown that the presence of shear wall alters significantly the load transfer among vertical members. It is also shown that whereas differential vertical deflections between adjacent vertical members are small owing to high stiffness of beams, the load transfer between them can be significant. Copyright © 2003 John Wiley & Sons, Ltd.
Theoretical analysis of post‐peak flexural behaviour of normal‐ and high‐strength concrete beams
Authors: Ho J. C. M. , Kwan A. K. H. , Pam H. J.
Published: June 2003

A new method of analysing the post‐peak flexural behaviour of reinforced concrete beams has been developed and applied to normal‐ and high‐strength concrete beams. It was revealed that at the post‐peak stage the neutral axis depth keeps on increasing, and at a certain point the strain in the tension reinforcement starts to decrease, even though the curvature is increasing monotonically. Such strain reversal in the tension reinforcement occurs in all concrete beams and has significant effects on the post‐peak behaviour and flexural ductility of concrete beams. Therefore, the stress path dependence of the tension reinforcement needs to be taken into account in the analysis. By means of a parametric study, the variation of ultimate concrete strain with tension steel ratio and the effects of various structural parameters on flexural ductility have been studied. Based on the numerical results, design values of ultimate concrete strain that are independent of tension steel ratio have been recommended and a simple formula for predicting the flexural ductility of reinforced normal‐ and high‐strength concrete beams has been developed. Copyright © 2003 John Wiley & Sons, Ltd.
Impact wave propagation in tall buildings using advanced spectral element method
Authors: Horr A. M. , Safi M.
Published: June 2003

One of the major divisions in analysis and design of tall buildings is to account for forces induced by flying‐object impact and the subsequent progressive collapse. During the past three decades, problems of contact mechanics have been considered by some authors, and special attention has been devoted to high‐speed impact. Impact wave propagation in tall buildings may be analysed using the conventional finite element method. However, in order to guarantee stability and accuracy of the solution, the number of elements used to model the structure may be very large indeed; more precisely, accurate results can be obtained after a substantial computational effort. In this respect, an improved complex spectral element method is developed for analysing the wave propagation problems in large structures. The purpose of this paper is to obtain the resulting dynamic responses of a tall building induced by a high‐speed impact of a flying object. Copyright © 2003 John Wiley & Sons, Ltd.
Fluid viscous dampers for high‐rise buildings
Authors: McNamara Robert J. , Taylor Douglas P.
Published: June 2003

Using supplemental fluid viscous dampers to dissipate energy and reduce building response to dynamic inputs is gaining worldwide acceptance. The concept of supplemental dampers added to a structure is that they absorb much of the energy input to the structure from a transient, not by the structure itself, but rather by supplemental damping elements. This paper presents an application of fluid viscous dampers in a high‐rise structure to suppress the anticipated wind‐induced accelerations. The description of the damping system, the design criteria and cost data are discussed. The viscous damper system proves to be a very cost‐effective method to reduce wind motions. Copyright © 2003 John Wiley & Sons, Ltd.
Structural performance of multi‐outrigger‐braced tall buildings
Authors: Wu J. R. , Li Q. S.
Published: June 2003

The optimum designs of multi‐outriggers in tall building structures are presented and discussed in this paper, through the analysis of structural performance of outrigger‐braced frame‐core structures. The influences of the locations of outriggers and the variations of structural element stiffness on the base moment in core, top drift and fundamental vibration period of such tall building structures are analysed in detail. A non‐linear optimum design procedure for reducing the base moment in the core is presented based on the penalty function method. The computer programs are developed on the basis of the proposed methods for analysing the behaviour and optimum design of multi‐outrigger structures. A series of figures presented in this paper can be used for the design purposes of outrigger‐braced tall building structures. Copyright © 2003 John Wiley & Sons, Ltd.
Reduced order control for wind‐induced vibrations of tall buildings
Authors: Li Q. S.
Published: June 2003

The design of a structural control system for a tall building may not be easy owing to the large number of degrees of freedom involved. Obviously, it is much easier to design a structural control system for the reduced‐order system than for the full‐order system. Model reduction is thus useful when control systems are implemented in civil engineering structures. A reduced‐order modelling technology for vibration control of wind‐excited tall buildings is presented and its performance is studied. The important issues associated with wind‐induced vibrations, model condensations and reduced‐order control are addressed. Finally, a numerical example, a tall building with an active tuned mass damper or a passive tuned mass damper, is given to show the efficiency of the reduced‐order control technique. Copyright © 2003 John Wiley & Sons, Ltd.
Wind Turbine Control for Load Reduction
Authors: Bossanyi E. A.
Published: June 2003

This article reviews techniques for the control of wind turbines during power production. Pitch control is used primarily to limit power in high winds, but it also has an important effect on structural loads. Particularly as turbines become larger, there is increasing interest in designing controllers to mitigate loads as far as possible. Torque control in variable‐speed turbines is used primarily to maximize energy capture below rated wind speed, and to limit the torque above rated, but it can also be used to reduce certain loads. The design of the control algorithms is clearly of prime importance. Additional sensors such as accelerometers and load sensors can also help the controller to achieve its objectives more effectively. By controlling the pitch of each blade independently, it is also possible to achieve important further reductions in loading. It is important to be able to quantify the benefits of any new controller. Although computer simulations are useful, field trials are also vital. The variability of the real wind means that particular care is needed in the design of the trials. Copyright © 2003 John Wiley & Sons, Ltd.
Immunocontraception of captive exotic species. III. Contraception and population management of fallow deer (Cervus dama)
Authors: Deigert Fred A. , Duncan Ann E. , Frank Kim M. , Lyda Robin O. , Kirkpatrick Jay F.
Published: June 2003

Immunocontraception has become an increasingly valuable tool in the population management of captive exotic ungulates. Although porcine zona pellucida vaccine (PZP) was used successfully in other cervids, a previous study with fallow deer (Cervus dama) suggested that the vaccine did not work in this species. In the current study, PZP was tested in two captive herds of fallow deer. Antibody titers were monitored over a 3‐year period to evaluate three different adjuvant protocols, and the vaccine was applied to an entire herd to determine the impact on fawning rates. In a semi‐free‐ranging herd, antibody titers rose from preimmunization levels of 2.6% of positive control serum to 56.5% 4 weeks after initial inoculations, to 65.1% at 1 year, and to 81.3% at 2 years, after a single annual booster was applied. Fawn production in this herd was reduced significantly over 3 years. The adjuvant protocol of Freund's Modified Adjuvant® (FMA) for the initial inoculation followed by a booster with Freund's Incomplete Adjuvant® (FIA), and the protocol of FMA for the initial inoculation followed in 3 weeks by a booster with FMA both produced significantly higher antibody titers than the 3× FIA (3 weeks apart) protocol after year 1. The FMA+FMA protocol produced significantly higher titers than the 3× FIA protocol at year 2, but was not different from the titers produced by the FMA+FIA protocol at year 2. Zoo Biol 22:261–268, 2003. © 2003 Wiley‐Liss, Inc.
Down‐regulation of heat shock protein 27 in neuronal cells and non‐neuronal cells expressing mutant ataxin‐3
Authors: Wen Feng-Chen , Li Yen-Hsien , Tsai Hui-Fang , Lin Chao-Hsiung , Li Chuan , Liu Chin-San , Lii Chong-Kuei , Nukina Nobuyuki , Hsieh Mingli
Published: June 2003

Machado–Joseph disease (MJD)/spinocerebellar ataxia type 3 is an autosomal dominant spinocerebellar degeneration characterized by a wide range of clinical manifestations. Unstable CAG trinucleotide repeat expansion in the MJD gene has been identified as the pathologic mutation of MJD. In this study, human SK‐N‐SH neuroblastoma cells stably transfected with full‐length MJD with 78 CAG repeats were established. Compared with the parental cells, cells expressing mutant ataxin‐3 displayed normal morphology for over 80 generations. Less than 1% of the transfected cells contained nuclear aggregates under basal conditions, indicating that this cellular model represented an early disease stage. While t‐butyl hydroperoxide (TBH) was used to assess the oxidative tolerance of cells, the results demonstrated that the transfected cells were more susceptible to low concentrations of TBH than the parental cells. Most interestingly, from 2D gel electrophoresis analysis, we identified that the expression of heat shock protein 27 (HSP27), known as a suppressor of poly(Q)‐mediated cell death, dramatically decreased in SK‐N‐SH cells stably transfected with full‐length mutant MJD. The same reduction of HSP27 was further confirmed in lymphoblastoid cells from MJD patients. Our results demonstrated that both neuronal and non‐neuronal cells with expanded full‐length ataxin‐3 revealed reduced protein expression of HSP27. We propose that the reduction of HSP27 in the early stage of the disease plays an important role during cell death process in MJD.
The murine telomerase catalytic subunit shares the PAb‐240 mutant specific epitope of the p53 protein
Authors: Shats Igor , Milyavsky Michael , Erez Neta , Rotter Varda
Published: June 2003

Many tumorigenic p53 mutants gain a common antigenic epitope that is recognized by the PAb‐240 antibody. Database search identified the presence of this epitope in several other proteins, including several antibodies and the catalytic subunit of mouse telomerase, mTERT. These antibodies may represent a part of the previously demonstrated anti‐idiotypic network built around p53. In the present study we demonstrate that the PAb‐240 antibody was able to inhibit telomerase activity in extracts from both mouse and human tumor cells. The recognition of mTERT by PAb‐240 is demonstrated by Western blotting and by using blocking peptides derived from mTERT. The existence of a shared epitope between mutant p53 and telomerase may suggest that the two proteins contribute to malignant transformation through a common pathway.
Association of liver steatosis with lipid oversecretion and hypotriglyceridaemia in C57BL/6j mice fed trans‐10,cis‐12‐linoleic acid
Authors: Degrace Pascal , Demizieux Laurent , Gresti Joseph , Chardigny Jean-Michel , Sébédio Jean-Louis , Clouet Pierre
Published: June 2003

Conjugated linoleic acids (CLA) have recently been recognized to reduce body fat and plasma lipids in some animals. This study demonstrated that the steatosis accompanying the fat loss induced by trans‐10,cis‐12‐C18:2 (CLA2) and not cis‐9,trans‐11‐C18:2 (CLA1) isomer in C57BL/6j mice was not due to an alteration of the liver lipoprotein production that was even increased. The 3‐fold decrease in plasma triacylglycerol contents and the induction of mRNA expression of low‐density lipoprotein receptors concomitantly observed in CLA2‐fed mice suggested an increase in the lipoprotein clearance at the level of the liver itself. CLA1 feeding produced similar but attenuated effects on triglyceridaemia only.
On the systematic position of the lichen genus Heppia
Authors: Schultz Matthias , Büdel Burkhard
Published: June 2003

The systematic position of the lichen genus Heppia in the order Lichinales was investigated. 18S rDNA sequence data were analyzed using a Bayesian approach to infer phylogeny using Markov chain Monte Carlo methods. The Lichinales are divided at family level into the sister groups Lichinaceae and Peltulaceae. The genus Heppia forms a highly supported clade in the family Lichinaceae. It is shown that the genus Heppia is morphologically well circumscribed within the Lichinaceae. As a nomenclatural consequence, the family name Heppiaceae is placed into synonymy under the older name Lichinaceae.
Light spots on cloning, stem cells and disease fighting
Authors: Nonchev Pr. Stefan
Published: June 2003

« De la transgenèse animale à la biothérapie chez l'homme»: Ed. Moshe Yaniv and Nicole Le Douarin
Bone mineral density and biochemical markers of bone turnover in aseptic loosening after total hip arthroplasty
Authors: Wilkinson J. Mark , Hamer Andrew J. , Rogers Angela , Stockley Ian , Eastell Richard
Published: June 2003

The aims of this study were to determine whether subjects with aseptic loosening after total hip arthroplasty (THA) have regional differences in periprosthetic bone mineral density (BMD) and systemic biochemical markers of bone turnover compared to subjects with successful implants.

Proximal femoral and pelvic BMD were measured by dual energy X‐ray absorptiometry and bone turnover markers were assayed in 49 subjects 12.6 ± 4.3 (mean ± SD) years after cemented THA. Femoral BMD was lower in Gruen zones 2, 5, 6, and 7 in subjects with a loose femoral implant (n = 17) compared to those (n = 32) with fixed femoral implants (P < 0.05 all comparisons). This BMD difference was greatest (−31%, P = 0.02) in the proximal and medial region of the femur. Subjects with femoral loosening had higher levels of the bone resorption marker N‐telopeptides of type‐I collagen (P = 0.02) than those with a fixed femoral implant. No differences in pelvic BMD or bone turnover markers were found between subjects with loose (n = 18) versus fixed (n = 31) pelvic implants.

This study suggests that failure of femoral components after cemented THA is associated with region‐specific decreases in BMD and an increase in urinary excretion of N‐telopeptide cross‐links of type‐I collagen. These surrogate outcome markers may be of value in monitoring response to antiresorptive therapies used to treat periprosthetic osteolysis, although the diagnosis of aseptic loosening remains clinical and radiological. © 2003 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Noninvasive fatigue fracture model of the rat ulna
Authors: Tami A. E. , Nasser P. , Schaffler M. B. , Tate M. L. Knothe
Published: June 2003

Fatigue damage occurs in response to repeated cyclic loading and has been observed in situ in cortical bone of humans and other animals. When microcracks accumulate and coalesce, failure ensues and is referred to as fatigue fracture. Experimental study of fatigue fracture healing is inherently difficult due to the lack of noninvasive models. In this study, we hypothesized that repeated cyclic loading of the rat ulna results in a fatigue fracture. The aim of the study was to develop a noninvasive long bone fatigue fracture model that induces failure through accumulation and coalescence of microdamage and replicates the morphology of a clinical fracture. Using modified end‐load bending, right ulnae of adult Sprague‐Dawley rats were cyclically loaded in vivo to fatigue failure based on increased bone compliance, which reflects changes in bone stiffness due to microdamage. Preterminal tracer studies with 0.8% Procion Red solution were conducted according to protocols described previously to evaluate perfusion of the vasculature as well as the lacunocanalicular system at different time points during healing. Eighteen of the 20 animals loaded sustained a fatigue fracture of the medial ulna, i.e. through the compressive cortex. In all cases, the fracture was closed and non‐displaced. No disruption to the periosteum or intramedullary vasculature was observed. The loading regime did not produce soft tissue trauma; in addition, no haematoma was observed in association with application of load. Healing proceeded via proliferative woven bone formation, followed by consolidation within 42 days postfracture. In sum, a noninvasive long bone fatigue fracture model was developed that lends itself for the study of internal remodeling of periosteal woven bone during fracture healing and has obvious applications for the study of fatigue fracture etiology. © 2003 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Cod in fjords and coastal waters of North Norway: distribution and variation in length and maturity at age
Authors: Berg Erik , Albert Ole Thomas
Published: June 2003

The distribution of cod along the Norwegian coast and in fjords from 62°N north to the Russian border was examined using data from annual trawl surveys carried out between 1995 and 2001. Based on differences in growth zones of the otoliths, cod are traditionally classified into two types: Northeast Arctic cod and coastal cod. Both types were found throughout the area investigated. The catch rate of both increased northwards and from offshore to inshore. In a statistical model of length at age, abiotic factors such as area and year of capture explained more of the variance than biotic factors such as sex, stage of maturity, and type of cod. Length at age increased in a southward direction and was higher for cod captured offshore than for those captured inshore. In a statistical model of the proportion mature at age, area, type, and year of capture explained more of the variance than sex and depth of capture. On average, coastal cod attained 50% maturity (M50) more than a year younger than a year younger than Northeast Arctic cod attained maturity. Although there were relatively large differences in age at maturity between neighbouring areas, age at maturity was lowest in the south and inshore, and in general, lower inshore than offshore. As genetic analysis clearly indicates that cod in the study area consist of at least two genetically separated stocks, it is likely that the differences found here in age at M50 might have a genetic component.
Antioxidants prevent UV‐induced apoptosis by inhibiting mitochondrial cytochrome c release and caspase activation in Spodoptera frugiperda (Sf9) cells
Authors: Mohan Manjari , Taneja Tarvinder K. , Sahdev Sudhir , Mohareer Krishnaveni , Begum Rasheedunnisa , Athar Mohammad , Sah Nand K. , Hasnain Seyed E.
Published: June 2003

Oxidative stress has been shown to be associated with apoptosis (programmed cell death) in a number of cell systems. We earlier reported in vitro cultured Spodoptera frugiperda (Sf9) cells as a model system to study oxidative stress induced apoptosis (J Biosciences 24 (1999) 13) and the inhibition of UV‐induced apoptosis by the baculovirus antiapoptotic p35 protein that acts as a sink to sequester reactive oxygen species (Proc Natl Acad Sci USA 96 (1999) 4838). We now show that UV‐induced apoptosis in Sf9 cells, is preceded by the release of mitochondrial cytochrome c into the cytosol and consequent activation of Sf‐caspase‐1. The inhibitory effect of different antioxidants including scavengers of oxygen radicals such as butylated hydroxyanisole (BHA), alpha tocopherol acetate, benzoate and reduced‐glutathione (GSH) on ultra violet B (UVB)‐induced apoptosis in cultured Sf9 cells was assessed. Both, cytochrome c release as well as Sf‐caspase‐1 activation was inhibited by pre‐treatment with antioxidants such as BHA and alpha tocopherol acetate, suggesting that these antioxidants inhibit apoptosis by acting quite upstream in the apoptosis cascade at the mitochondrial level, as well as downstream at the caspase level.
Dynamic changes in connexin expression correlate with key events in the wound healing process
Authors: Coutinho Petula , Qiu Cindy , Frank Stefanie , Tamber Kamaldeep , Becker David
Published: June 2003

Wound healing is a complex process requiring communication for the precise co‐ordination of different cell types. The role of extracellular communication through growth factors in the wound healing process has been extensively documented, but the role of direct intercellular communication via gap junctions has scarcely been investigated. We have examined the dynamics of gap junction protein (Connexins 26, 30, 31.1 and 43) expression in the murine epidermis and dermis during wound healing, and we show that connexin expression is extremely plastic between 6 hours and 12 days post‐wounding. The immediate response (6 h) to wounding is to downregulate all connexins in the epidermis, but thereafter the expression profile of each connexin changes dramatically. Here, we correlate the changing patterns of connexin expression with key events in the wound healing process.
Exportin 1‐independent nuclear export of GAPDH
Authors: Schmitz Hans‐Dirk , Dutiné Christine , Bereiter‐Hahn Jürgen
Published: June 2003

Glyceraldehyde‐3‐phosphate dehydrogenase (GAPDH) is a key enzyme of the glycolytic pathway. Recent studies have demonstrated an additional role in apoptosis: GAPDH is targeted to the nucleus during apoptotic signalling. This nuclear transport has also been observed in serum‐depleted cells, but it is reversible in fibroblasts, in contrast to apoptotic‐induced transport (Eur J Cell Biol 80 (2001) 419). Here, we analyse the serum depletion‐induced transport processes of GAPDH in NIH 3T3 cells. Prolonged serum depletion did not cause cell death, nuclear fragmentation (hoechst staining) or a significant increase in DNA strand‐breaks (comet assay). Using cells expressing green fluorescent protein (GFP)‐tagged GAPDH allowed us to monitor its intracellular localisation by confocal laser scanning microscopy (CLSM). Treatment of cells with the exportin1 inhibitor leptomycin B (LMB) did not influence cytoplasmic localisation of GFP—GAPDH, indicating that nuclear targeting of GAPDH is not constitutive and may be altered via a serum‐dependent regulatory export process. Suprisingly, the export of nuclear GFP—GAPDH after re‐addition of serum to starved cells was not prevented by LMB. Thus, nuclear export of GAPDH upon serum depletion is not mediated by exportin1.
Prognostic value of 6‐minute walk corridor test in patients with mild to moderate heart failure: comparison with other methods of functional evaluation
Authors: Rostagno Carlo , Olivo Giuseppe , Comeglio Marco , Boddi Vieri , Banchelli Michela , Galanti Giorgio , Gensini Gian Franco
Published: June 2003

Aim:

The study was designed to evaluate the prognostic value of the 6‐min walk test (6MWT) in patients with mild to moderate congestive heart failure (CHF).

Methods and results:

Two hundred and fourteen patients (119 men and 95 women, mean age 64 years) were followed for a mean period of 34 months to assess event‐free survival (death, heart transplantation). Sixty‐six patients (34%) died (63 cardiovascular causes, 2 cancer and 1 stroke) and five patients underwent heart transplantation. For patients who walked <300 m during the 6MWT, survival was 62% compared with 82% in patients who walked 300–450 m or>450 m. With univariate analysis, NYHA class was the strongest predictor of death. LVEF (P<0.0001), aetiology of heart failure (P<0.001), LV filling pattern (P=0.002) and 6MWT distance (P<0.01) were all significantly related to survival. No significant relationship was found between survival, peak oxygen consumption or anaerobic threshold. Multivariate analysis using the Cox‐stepwise regression model showed that LV fractional shortening (P<0.009) and 6MWT distance (P<0.0005) were the strongest prognostic markers.

Conclusion:

A 6MWT distance of <300 m is a simple and useful prognostic marker of subsequent cardiac death in unselected patients with mild to moderate CHF.
Nondirectiveness and Its Lay Interpretations: The Effect of Counseling Style, Ethnicity and Culture on Attitudes Towards Genetic Counseling Among Jewish and Bedouin Respondents in Israel
Authors: Raz Aviad E. , Atar Marcela
Published: June 2003

To evaluate the effects of ethnicity, culture, and counseling style on the interpretation of nondirectiveness in genetic counseling, a questionnaire containing premarital and prenatal case vignettes in two versions (pessimistic/optimistic) was administered to 281 Jewish and 133 Bedouin respondents. The first study population was comprised of Jewish students enrolled in a university and a community college in the Negev (southern part of Israel). The second study population was comprised of Muslim‐Bedouin college students from the same area. The majority of Jewish respondents interpreted the nondirective message as intended by counselors, while the majority of Bedouin respondents did not. Counseling style was found to have a statistically significant effect on the interpretation of the general role of counseling. Gender and susceptibility were not found to have a significant effect on interpretation. Group differences are analyzed through a cultural lens in which different interpretive norms can generate expectations for either nondirectiveness or directiveness.
Subjective and Objective Risks of Carrying a BRCA1/2 Mutation in Individuals of Ashkenazi Jewish Descent
Authors: Kelly Kimberly , Leventhal Howard , Toppmeyer Deborah , Much Judy , Dermody James , Marvin Monica , Baran Jill , Schwalb Marvin
Published: June 2003

This repeated measures study examines (1) the change in subjective risk of mutations pre‐ to postcounseling, (2) the accuracy of BRCAPRO estimates of mutations, and (3) the discrepancy between subjective risk and BRCAPRO estimates of mutations before and after genetic counseling. Ninety‐nine Ashkenazi Jewish individuals pursued testing for BRCA1/2 mutations. Most had a personal cancer history (N = 51; family only: N = 48); and received uninformative negative results (N = 66; positives: N = 23; informative negative: N = 10). The coping strategy of defensive pessimism predicts that individuals will believe the worst case scenario to better cope with a potential negative outcome. Consistent with this, most felt they would have a mutation, if not mutations in both genes. The BRCAPRO model appeared to overestimate risk of having a mutation in this sample (p < .001). BRCAPRO overestimates notwithstanding, genetic counseling increased accuracy of subjective risk (p < .01). Individuals with a family‐only cancer history had the least accurate estimates of risk (p < .05) and may need further intervention to either manage anxiety or improve knowledge.
Oppression and Discrimination among Lesbian, Gay, Bisexual, and Transgendered People and Communities: A Challenge for Community Psychology
Authors: Harper Gary W. , Schneider Margaret
Published: June 2003

Lesbian, gay, bisexual, and transgendered (LGBT) people continue to experience various forms of oppression and discrimination in North America and throughout the world, despite the social, legal, and political advances that have been launched in an attempt to grant LGBT people basic human rights. Even though LGBT people and communities have been actively engaged in community organizing and social action efforts since the early twentieth century, research on LGBT issues has been, for the most part, conspicuously absent within the very field of psychology that is explicitly focused on community research and action–Community Psychology. The psychological and social impact of oppression, rejection, discrimination, harassment, and violence on LGBT people is reviewed, and recent advances in the areas of LGBT health, public policy, and research are detailed. Recent advances within the field of Community Psychology with regard to LGBT research and action are highlighted, and a call to action is offered to integrate the knowledge and skills within LGBT communities with Community Psychology's models of intervention, prevention, and social change in order to build better theory and intervention for LGBT people and communities.
The Obligations of the Moral–Scientific Stance
Authors: Sarason Seymour B.
Published: June 2003

One of the most important contributions of community psychology is to have community interventions that have intended outcomes and to describe the intervention in ways that are sufficiently complete and replicable. However, the descriptions we have are too incomplete. A suggestion is made for how the field should take steps to remedy the weaknesses.
Review Article: Chiari Type I Malformation with or Without Syringomyelia: Prevalence and Genetics
Authors: Speer Marcy C. , Enterline David S. , Mehltretter Lorraine , Hammock Preston , Joseph Judith , Dickerson Margaret , Ellenbogen Richard G. , Milhorat Thomas H. , Hauser Michael A. , George Timothy M.
Published: June 2003

Chiari type I malformation has traditionally been defined as a downward herniation of the cerebellar tonsils of ≥5 mm through the foramen magnum and it is likely associated with a volumetrically reduced posterior fossa. Syringomyelia is commonly associated with Chiari type I malformation. We estimate the prevalence of these two conditions and determine that they are more common than previously expected. We identify the genetic syndromes associated with some cases of Chiari type I malformation, and we provide evidence in favor of a genetic hypothesis for at least a subset of the nonsyndromic cases.
The Mpowerment Project: Community‐Building with Young Gay and Bisexual Men to Prevent HIV
Authors: Hays Robert B. , Rebchook Gregory M. , Kegeles Susan M.
Published: June 2003

The Mpowerment Project is a community‐level HIV prevention intervention for young gay and bisexual men ages 18–27. The program seeks to build a strong, supportive young gay and bisexual men's community where young gay and bisexual men nurture and protect each other, particularly with regard to HIV prevention. The program's theoretical framework draws from the areas of diffusion of innovations, community organizing, peer influence, and personal empowerment. The Mpowerment Project promotes a norm for safer sex through a variety of social, outreach and small group activities. The project is run by a “Core Group” of 12–15 young gay and bisexual men who, with volunteers, design and carry out all project activities. Implemented in 4 communities (Eugene, OR; Santa Barbara, CA; Albuquerque, NM; Austin, TX), the Mpowerment Project has proven to be effective in reducing high risk sex. This paper discusses the development and implementation of the program and various challenges encountered.