bluuebunny/crossref_metadata_2025_split huggingface dataset:
Surface Aspects in Fatigue of Shape Memory Alloys (SMA)
Authors: Hornbogen E. , Eggeler G. 
Published: April 2004

AbstractThe present paper briefly reviews the role of surfaces in fatigue of shape memory alloys (SMAs). When polished and defect free austenitic surfaces are cooled to lower temperatures, the martensitic transformation creates a pattern of surface upheavals; and an inverse pattern forms when polished and defect free martensite is heated. In full transformation cycles (heating followed by cooling or cooling followed by heating) high quality surfaces can only be re‐established if no fatigue occurs. After multiple cycling intrusions and extrusions can be detected which represent fatigue damage accumulation. Cracks can grow from extrusions and intrusions. We also show that fatigue cracking can start from surface defects which are for example introduced by wire drawing. We then briefly discuss surface treatments which are intended to improve fatigue resistance of shape memory alloys. These may consist in the modification of the SMA microstructure in the surface region (by deformation or diffusion treatments). They can also involve coating procedures where other elements are deposited on the SMA surface. However, SMA performance and the intensity of exploitable SM effects are usually reduced by surface treatments.
Phrenic nerve transfer in the treatment of brachial plexus avulsion: An experimental study of nerve regeneration and muscle morphology in rats
Authors: Zhang Cheng‐Gang , Ma Jian‐Jun , Terenghi Giorgio , Mantovani Cristina , Wiberg Mikael 
Published: April 2004

AbstractThe regeneration of motor and sensory neurons and the morphological changes of the target muscle after phrenic nerve transfer were investigated in adult rats. Six months following nerve transfer, 326.0 ± 16.31 phrenic motoneurons regenerated into musculocutaneous nerve, which is not different from the normal number of phrenic motoneurons. The regenerated motoneurons exhibited a 14% nonsignificant hypertrophy. Of the dorsal root ganglia (DRG) neurons, 255.8 ± 45.26 regenerated, which was significantly lower than the number of normal phrenic DRG neurons. The regenerated phrenic DRG neurons showed a 24% close‐to‐significant atrophy. The target muscle fiber morphology changed considerably after reinnervation. The present results suggest that the phrenic nerve has very good regenerative ability in terms of its motoneurons and a relatively insufficient sensory neuronal regeneration. © 2004 Wiley‐Liss, Inc.
Large‐scale local search heuristics for the capacitated vertex p‐center problem
Authors: Scaparra Maria Paola , Pallottino Stefano , Scutellà Maria Grazia 
Published: April 2004

AbstractThis article investigates the application of very large neighborhood search techniques for solving the capacitated vertex p‐center problem. We characterize a local search neighborhood in terms of path and cyclic exchanges of customers among facilities, and exploit principles borrowed from network optimization theory to efficiently detect cost‐decreasing solutions in such a neighborhood. We complement the multiexchange methodology with a relocation mechanism specifically designed to perform facility location adjustments. The validity of the proposed approach is supported by empirical investigation and performance comparisons with the commercial code CPLEX. © 2004 Wiley Periodicals, Inc.
Thermotropic liquid‐crystalline polyesters containing biphenyl mesogens in the main chain: The effect of connectivity
Authors: Ranganathan T. , Ramesh C. , Kumar Anil 
Published: April 2004

AbstractA homologous series of main‐chain thermotropic liquid‐crystalline polyesters containing rigid biphenyl mesogen and flexible methylene spacers were synthesized with the AB‐type self‐polycondensation approach. The polyesters were characterized with 1H NMR, gel permeation chromatography, thermogravimetric analysis, differential scanning calorimetry, polarized light optical microscopy, and X‐ray diffraction. These polyesters, containing trimethylene spacers on the acid side and various spacers on the alcohol side of the biphenyl mesogen, showed an odd–even effect in the transition temperatures and mesophase type. The even members showed higher transition temperatures than the odd ones. A normal smectic mesophase was observed for the even members, whereas the odd‐membered counterparts exhibited a tilted smectic mesophase. To study the effect of connectivity, the mesophase characteristics of these polyesters were compared with those of the isomeric AB‐type polyesters without any methylene spacer on the acid side of the biphenyl moiety. The mesophase characteristics were insensitive to whether the mesogen was connected to a carboxyl unit or a methylene unit. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2734–2746, 2004
Polyesterification of aromatic dicarboxylic acids and bisphenols with tosyl chloride/dimethylformamide/pyridine promoted by the improvement of the difficult solubility of the activated diacids with lithium chloride
Authors: Higashi Fukuji , Kira Kaori 
Published: April 2004

AbstractThe solution polyesterification of dicarboxylic acids in pyridine, the activated intermediates of which were difficult to dissolve in tosyl chloride/dimethylformamide/pyridine, was investigated in the presence of lithium chloride. The solubility of the activated dicarboxylic acids was largely improved by the presence of the salt, and the polycondensation with bisphenols was greatly facilitated. The salt was more effectively added to a pyridine solution of dicarboxylic acids than to the activated dicarboxylic acids in pyridine. The favorable additive effect on the improved solubility was attributed to a lowered degree of association of the activated dicarboxylic acids, which led to distributions of the resulting oligomers from bisphenols at an earlier stage closer to the theoretical ones and yielded better polycondensation results. The reaction, which proceeded through favorable distributions of the co‐oligomers, produced copolymers of higher inherent viscosities and slightly block sequence distributions determined by NMR. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2725–2733, 2004
SEN virus infection
Authors: Sagir Abdurrahman , Kirschberg Oliver , Heintges Tobias , Erhardt Andreas , Häussinger Dieter 
Published: April 2004

AbstractThe SEN virus (SEN‐V) belongs to a recently discovered group of DNA viruses whose members (SEN‐V‐D and SEN‐V‐H) are associated with post‐transfusion hepatitis. It is a single‐stranded circular, non‐enveloped DNA virus of ∼3600 to ∼3800 nucleotides with at least three open reading frames (ORFs). Eight different strains of SEN‐V have been identified and provisionally classified as members of the Circoviridae family, a group of small, single‐stranded, non‐enveloped circular DNA viruses that includes the TT virus (TTV), TUS01, SANBAN, PMV and YONBAN. Prevalences in different populations show great variability with marked differences between different countries and groups. Although parenteral transmission is very likely, other routes of transmission cannot be excluded. Mother to infant transmission has been demonstrated. The effect of SEN‐V on chronic liver diseases has been studied. The influence of SEN‐V on the response to HCV therapy was investigated in three studies, with contradictory results. Data for other acute and chronic liver diseases are sparse. Further studies are needed to define the pathogenesis and clinical importance of SEN‐V infection. Copyright © 2004 John Wiley & Sons, Ltd.
Building uniformly random subtrees
Authors: Luczak Malwina , Winkler Peter 
Published: April 2004

AbstractWe prove the existence of, and describe, a (random) process which builds subtrees of a rooted d‐branching tree one node at a time, in such a way that the subtree created at stage n is precisely a uniformly random subtree of size n. The union of these subtrees is a “uniformly random” infinite subtree, which we describe and generate in several ways. Generalization to generation of other combinatorial structures is also considered. © 2004 Wiley Periodicals, Inc. Random Struct. Alg., 2004
Does the Prentice criterion validate surrogate endpoints?
Authors: Berger Vance W. 
Published: April 2004

AbstractRandomized Phase II or Phase III clinical trials that are powered based on clinical endpoints, such as survival time, may be prohibitively expensive, in terms of both the time required for their completion and the number of patients required. As such, surrogate endpoints, such as objective tumour response or markers including prostate specific antigen or CA‐125, have gained widespread popularity in clinical trials. If an improvement in a surrogate endpoint does not itself confer patient benefit, then consideration must be given to the extent to which improvement in a surrogate endpoint implies improvement in the true clinical endpoint of interest. That this is not a trivial issue is demonstrated by the results of an NIH‐sponsored trial of anti‐arrhythmic drugs, in which the ability to correct an irregular heart beat not only did not correspond to a survival benefit but in fact led to excess mortality. One approach to the validation of surrogate endpoints involves ensuring that a valid between‐group analysis of the surrogate endpoint constitutes also a valid analysis of the true clinical endpoint. The Prentice criterion is a set of conditions that essentially specify the conditional independence of the impact of treatment on the true endpoint, given the surrogate endpoint. It is shown that this criterion alone ensures that an observed effect of the treatment on the true endpoint implies a treatment effect also on the surrogate endpoint, but contrary to popular belief, it does not ensure the converse, specifically that the observation of a significant treatment effect on the surrogate endpoint can be used to infer a treatment effect on the true endpoint. Published in 2004 by John Wiley & Sons, Ltd.
Should statisticians reporting to data monitoring committees be independent of the trial sponsor and leadership?
Authors: Ellenberg Susan S. , George Stephen L. 
Published: April 2004

AbstractIt has long been a fundamental principle of clinical trials that interim comparative data should be kept confidential, with such data accessible only to a small number of individuals responsible for its analysis and monitoring. The rationale for keeping investigators and sponsors blinded to interim data has been extensively discussed, but the possible conflicts of interest that could arise for the statistician who performs the analysis of the interim data and presents it to a data monitoring committee has received little attention. We describe these potential conflicts, and the advantages and disadvantages of approaches that might be taken to minimize them. We have invited commentary on this issue from several statisticians with substantial experience in clinical trials and interim data monitoring. Published in 2004 by John Wiley & Sons, Ltd.
The independent statistician for data monitoring committees
Authors: DeMets David L. , Fleming Thomas R. 
Published: April 2004

AbstractClinical trials are an essential part of the clinical research process. Recently, independent Data Monitoring Committees (DMCs) have been widely implemented to provide scientific and ethical oversight of pivotal clinical trials having irreversible outcomes such as death, stroke, disease recurrence or a serious adverse event. To carry out their responsibility, the DMC reviews interim analyses of accumulating data. We address the motivation for having the preparation and presentation of these interim analyses be conducted by an independent statistician who is not a member of the DMC and who is not the trial's lead or steering committee statistician. These views are based on having served as members of many DMCs as well as having been the independent statistician for several trials. Copyright © 2004 John Wiley & Sons, Ltd.
Building KidPad: an application for children's collaborative storytelling
Authors: Hourcade Juan Pablo , Bederson Benjamin B. , Druin Allison 
Published: April 2004

AbstractCollaborating in small groups can be beneficial to children's learning and socializing. However, there is currently little computer support for children's collaborative activities. This was our motivation for building KidPad, a collaborative storytelling tool for children. KidPad provides children with drawing, typing, and hyperlinking capabilities in a large, two‐dimensional canvas. It supports collaboration by accepting input from multiple mice. In building KidPad, we developed solutions to problems common to all single‐display groupware applications for children: using an intuitive user interface metaphor that can support collaboration, and obtaining input from multiple devices. We addressed the need for an appropriate user interface metaphor by using the local tools metaphor. In developing the concept of local tools we learned about the importance of addressing the issue of global modes. Our solution for obtaining input from multiple devices was MID, an architecture written in Java. In building MID, we learned about the importance of building flexible architectures that can support a wide range of applications and devices in a consistent manner, and that are easy to extend and use by programmers. This paper describes our work on local tools and MID in the context of building KidPad, and aims to provide developers with valuable insights into how to develop collaborative applications for children. Copyright © 2004 John Wiley & Sons, Ltd.
Quantitative major and trace elemental mapping by PIXE of concretionary pyrite from the Witwatersrand Basin, South Africa
Authors: Reimold W. U. , Przybylowicz W. J. , Gibson R. L. 
Published: April 2004

AbstractSeveral concretionary pyrite grains displaying multiple, massive sulphide or silicate inclusion‐rich, annuli from two gold‐bearing reef horizons (Ventersdorp Contact Reef, Kimberley Reefs) in different parts of the Witwatersrand Basin were analysed by particle‐induced X‐ray emission (PIXE) and electron microprobe analysis (EMPA) for their major and trace element compositions. Both PIXE spot analysis and mapping of the distributions of major and trace elements were carried out, and EMPA was employed to obtain major element abundances for matrix corrections of PIXE analysis. Spatial analysis by PIXE is excellent in comparison with EMPA, as PIXE detection limits are lower by 1–2 orders of magnitude at comparable, short‐duration counting times (12 h for 4096 pixel analyses by PIXE). EMPA was successful in the identification of individual zones, for example on the basis of locally enriched minor elements Ni or As. This technique also provided essential standard‐based control on major element abundances for the standardless PIXE dynamic analysis. The compositional results obtained on concretionary pyrite grains by PIXE are distinctly different for each analysed grain, in terms of relative enrichment of certain minor and trace elements in specific zones. Gold was detected locally in the interiors of grains and/or along grain margins. The different results are discussed with regard to their possible meaning related to the origin of gold mineralization in the Witwatersrand ore deposit. Copyright © 2004 John Wiley & Sons, Ltd.
Practical normal form computations for vector fields
Authors: Mayer S. , Scheurle J. , Walcher S. 
Published: April 2004

AbstractWe present a method to compute a Poincaré‐Dulac normal form of a vector field, as well as a corresponding reduced vector field, near a stationary point with arbitrary linearization. Explicit knowledge of the eigenvalues of the linearization is not necessary, and only rational operations are required. Some examples are presented, including a normal form computation relevant for Hopf bifurcations, and coupled nonlinear oscillators.
ProteoMix: an integrated and flexible system for interactively analyzing large numbers of protein sequences
Authors: Chikayama Eisuke , Kurotani Atsushi , Kuroda Yutaka , Yokoyama Shigeyuki 
Published: April 2004

Abstract
Summary: ProteoMix is a suite of JAVA programs for identifying, annotating and predicting regions of interest in large sets of amino acid sequences, according to systematic and consistent criteria. It is based on two concepts (1) the integration of results from different sequence analysis tools increases the prediction reliability; and (2) the integration protocol is critical and needs to be easily adaptable in a case-by-case manner. ProteoMix was designed to analyze simultaneously multiple protein sequences using several bioinformatics tools, merge the results of the analyses using logical functions and display them on an integrated viewer. In addition, new sequences can be added seamlessly to an analysis performed on an initial set of sequences. ProteoMix has a modular design, and bioinformatics tools are run on remote servers accessed using the Internet Simple Object Access Protocol (SOAP), ensuring the swift implementation of additional tools. ProteoMix has a user-friendly interactive graphical user interface environment and runs on PCs with Microsoft OS.
Availability: ProteoMix is freely available for academic users at http://bio.gsc.riken.jp/ProteoMix/.
Study of ochratoxin A‐producing strains in coffee processing
Authors: Suárez‐Quiroz Mirna , González‐Rios Oscar , Barel Michel , Guyot Bernard , Schorr‐Galindo Sabine , Guiraud Joseph‐Pierre 
Published: April 2004

SummaryOchratoxin A (OTA) is the main mycotoxin that has been detected in coffee. The occurrence of OTA in coffee beans can be because of environmental conditions and/or processing conditions. Three coffee processes were evaluated (wet, mechanical and dry processes), at different stages from harvesting to storage, and fungi producing OTA were enumerated and identified. The frequency of potential OTA‐producing fungi and their ability to produce OTA was also studied. By direct plating, the levels of contamination found in the coffee processes were 80, 72 and 92%, respectively, for parchment and dry cherry coffee and 20, 34 and 15% for green coffee. Aspergillus ochraceus isolated from the three processes accounted for 6.6, 8.3 and 3.3%, and Aspergillus niger for 15, 13 and 25% of the strains isolated, respectively. The toxigenic potential of five A. ochraceus and two A. niger strains was tested in FDA medium and coffee medium using the HPLC technique. There was no difference between the processes studied in terms of isolation and occurrence of ochratoxigenic fungi.
Race and the Incidence of Unemployment in South Africa
Authors: Kingdon Geeta Gandhi , Knight John 
Published: April 2004

AbstractSouth Africa's unemployment rate is one of the highest in the world, and it has important distributional implications. The paper examines both entry into and duration of unemployment using data for the mid‐1990s. A probit model of unemployment shows an important role for race, education, age, gender, home‐ownership, location, and numerous other variables, all of which have plausible explanations. The large race gap in unemployment is explored further by means of a decomposition analysis akin to that normally used to analyze wage discrimination. There remains a substantial residual which might represent unobserved characteristics, such as quality of education, or discrimination.
A Reexamination of the Time Path of Wage Differentials in Taiwan
Authors: Lin Chun‐Hung A. , Orazem Peter F. 
Published: April 2004

AbstractContrary to the conclusions of a recent paper by Chen and Hsu (Review of Development Economics, vol. 5, 2001, pp. 336–54), wage inequality and returns to college‐educated workers have risen in Taiwan since 1980. Government policies which have caused rapid expansion of the supply of new college graduates have depressed returns for only the youngest cohorts of college graduates. Older cohorts of college graduates experienced rising returns, as have college graduates as a whole. Young college‐educated women's returns fell more and older college‐educated women's returns rose more relative to their male counterparts. Consequently, the rising share of women in the labor force helped amplify these trends. Changing trade patterns have tended to increase labor demand in sectors that use educated labor more intensively, helping to raise returns to skill. However, in contrast to western economies, rising capital intensity does not appear to have accelerated the pay gap by skill in Taiwan.
Evidence that protease activated receptor 2 expression is enhanced in human coronary atherosclerotic lesions
Authors: Napoli C , de Nigris F , Wallace J L , Hollenberg M D , Tajana G , De Rosa G , Sica V , Cirino G 
Published: April 2004

Aim:To investigate protease activated receptor 2 (PAR-2) expression in human coronary atherosclerotic lesions because PAR-2 is involved in the modulation of inflammatory events and vascular function.Methods:An immunohistochemical analysis was performed on serial arterial sections, using the following antibodies: MDA2, a murine monoclonal antibody against malondialdehyde lysine epitopes of oxidised low density lipoprotein (oxLDL); HAM-56, a monoclonal antibody against human macrophages/foam cells; B5, a rabbit polyclonal antibody against PAR-2; and SAM11, a mouse monoclonal antibody against human PAR-2. Sections containing at least one lesion showing substantial immunostaining were counted as positive, and results were expressed as per cent of all sections of the same artery.Results:PAR-2 expression was enhanced in human coronary atherosclerotic lesions. This phenomenon correlated with an increase in oxLDL epitopes in the coronary artery.Conclusion:This study shows for the first time that PAR-2 expression is enhanced in human coronary atherosclerotic lesions, and suggests that PAR-2 dependent cellular trafficking may be one of the regulatory signalling responses to vascular injury. Further pharmacological studies will establish whether modulation (and in which direction) of PAR-2 represents a possible therapeutic target for controlling the vascular response to injury.
Inhibition of angiotensin I–converting enzyme induces radioprotection by preserving murine hematopoietic short-term reconstituting cells
Authors: Charrier Sabine , Michaud Annie , Badaoui Sabrina , Giroux Sébastien , Ezan Eric , Sainteny Françoise , Corvol Pierre , Vainchenker William 
Published: April 2004

AbstractAngiotensin I–converting enzyme (ACE) inhibitors can affect hematopoiesis by several mechanisms including inhibition of angiotensin II formation and increasing plasma concentrations of AcSDKP (acetyl-N-Ser-Asp-Lys-Pro), an ACE substrate and a negative regulator of hematopoiesis. We tested whether ACE inhibition could decrease the hematopoietic toxicity of lethal or sublethal irradiation protocols. In all cases, short treatment with the ACE inhibitor perindopril protected against irradiation-induced death. ACE inhibition accelerated hematopoietic recovery and led to a significant increase in platelet and red cell counts. Pretreatment with perindopril increased bone marrow cellularity and the number of hematopoietic progenitors (granulocyte macrophage colony-forming unit [CFU-GM], erythroid burst-forming unit [BFU-E], and megakaryocyte colony-forming unit [CFU-MK]) from day 7 to 28 after irradiation. Perindopril also increased the number of hematopoietic stem cells with at least a short-term reconstitutive activity in animals that recovered from irradiation. To determine the mechanism of action involved, we evaluated the effects of increasing AcSDKP plasma concentrations and of an angiotensin II type 1 (AT1) receptor antagonist (telmisartan) on radioprotection. We found that the AT1-receptor antagonism mediated similar radioprotection as the ACE inhibitor. These results suggest that ACE inhibitors and AT1-receptor antagonists could be used to decrease the hematopoietic toxicity of irradiation.