bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of Helical Polyanilines Using Chondroitin Sulfate as a Molecular Template
Authors: Yuan Guo‐Li , Kuramoto Noriyuki 
Published: August 2004

AbstractSummary: Water‐processable conducting polyaniline derivatives (PANIs), such as polyaniline (PANI), poly(o‐methylaniline) and poly(o‐methoxyaniline), were synthesized by in situ chemical polymerization of the corresponding achiral monomer in the presence of the novel chiral polymeric template, chondroitin sulfate. The resulting conducting PANIs were doped and complexed with chondroitin sulfate (CHS) to form intertwined intermacromolecular complexes of PANIs‐CHS, which was confirmed by UV‐vis and FTIR spectroscopy. The induction of the excess one‐handed helical structure into PANIs was confirmed by circular dichroism (CD) spectroscopy with the characteristic bisignate bands at approximately 400 and 450 nm for the emeraldine salt. The effect of ionic strength was investigated on the formation of the intertwined PANI‐CHS complex and the induction of chirality into PANI by adding NaCl to the reaction solution. The CD spectral change of PANI‐CHS in the cycle of dedoping and redoping was also studied, and it was found that intermacromolecular complexation helps to stabilize the chiral conformation in PANI against racemization. Interestingly enough, it was found that optically active PANI‐CHS exhibited pH‐sensitive chiroptical properties. A study of the conductivity, electrochemical activity and the chiroptical properties in different redox states of PANIs provided proof for their use as chiral electrode and electroactively chiral material.Structure of the complexes of PANIs‐CHS.magnified imageStructure of the complexes of PANIs‐CHS.
Synthesis and Characterization of Poly(glycolic acid‐alt‐6‐aminohexanoic acid) and Poly(glycolic acid‐alt‐11‐aminoundecanoic acid)
Authors: Vera Montserrat , Franco Lourdes , Puiggalí Jordi 
Published: August 2004

AbstractSummary: Poly(ester amide)s derived from glycolic acid and ω‐amino acid units, such as aminohexanoic or aminoundecanoic acids, are synthesized by a thermal polycondensation reaction that involves the formation of metal halide salts. Polymerization kinetics of different metal salts are studied by isothermal and nonisothermal methods and the corresponding parameters compared. The condensation reaction begins in the solid state for the aminohexanoic derivatives, although a rapid liquefaction is observed. On the other hand, the melting temperatures of the sodium and the potassium chloroacetylaminoundecanoate salts are lower than the reaction temperatures, and consequently polycondensation proceeds fully in the liquefied state. These polymers are characterized by an alternate disposition of ester and amide groups and can be obtained with high molecular weights and short polymerization times. Thermal properties (glass transition and melting temperatures) of the two new polymers are determined and compared. Thermal stability is also investigated; the results indicated that decomposition temperatures were always far from both reaction and polymer fusion temperatures.DSC heating scans performed at different rates for potassium chloroacetylaminoundecanote.magnified imageDSC heating scans performed at different rates for potassium chloroacetylaminoundecanote.
Back Cover: Macromol. Rapid Commun. 16/2004
Authors: Justynska Justyna , Schlaad Helmut 
Published: August 2004

Back Cover: The free‐radical addition of ω‐functional mercaptans onto polybutadiene‐based block copolymers represents a modular approach toward well‐defined block copolymers with, for example, ester, carboxylic acid, or amine functionalities. The modification reaction proceeds smoothly and yields quantitatively functionalized block copolymers without changing the molecular weight distribution of the parent copolymer.Further details can be found in the Communication by J. Justynska and H. Schlaad* on page 1478.
Scattering from Ferrogels
Authors: Jarkova Elena , Vilgis Thomas A. 
Published: August 2004

AbstractSummary: This paper introduces a simple mean‐field theory for gels with magnetic properties. The main emphasis in this paper is the discussion of the scattering properties. Therefore, a simple model is introduced, such that the chains carry magnetic moments along their main axis. Naturally these magnetic moments interact sensitively to theory orientation with each other. Thus a distinguished interplay between chain and dipole orientation induces strong coupling between the macroscopic deformation and magnetic properties. These effects can be experimentally demonstrated with scattering methods. Here some mean‐field expressions for the structure factors are predicted and discussed in some detail.The configurations adopted by polymers possessing a magnetic moment and undergoing dipole‐dipole interactions.imageThe configurations adopted by polymers possessing a magnetic moment and undergoing dipole‐dipole interactions.
A Study of Modification of M2 Cast High Speed Steel
Authors: Fu H. , Xing J. 
Published: August 2004

AbstractM2 cast high speed steel was inoculated by addition of rare earth(RE)‐Al‐N, network eutectic carbides were eliminated, matrix structures were refined and the segregation of tungsten and molybdenum elements were relieved. In the condition that the hardness did not decrease, impact toughness obviously increased. Quenching at 1180 °C and three‐times tempering at 560 °C, the hardness of M2 cast high speed steel kept 65~66HRC, impact toughness reached 21.3J/cm2. Modified M2 cast high speed steel had excellent thermal fatigue resistance and high temperature wear resistance. Roll made in modified M2 cast high speed steel had excellent service effect using in slit rolling mill stand of hot rolling bar mill.
Laserstrahlschweißen von Titanwerkstoffen unter Berücksichtigung des Einflusses des Sauerstoffes
Authors: Bergmann J. P. 
Published: August 2004

AbstractIm Rahmen dieses Aufsatzes wird erstmalig ein innovatives Konzept zum Laserstrahlschweißen von Titan für die Serienfertigung dargestellt und validiert. Durch den neuartigen Einsatz eines 6‐lagigen Metallgewebes ist es möglich, die Strömung vom Schutzgas so stark zu beruhigen, dass die beim Schweißen schädlichen Verwirbelungen vermieden werden können. Der Einbau eines derartigen Gewebes als Boden einer offenen Schweißkammer ermöglicht sowohl das mechanisierte als auch das vollautomatisierte Schweißen von hochreaktiven Werkstoffen, wie zum Beispiel Titanwerkstoffen, unter atmosphärischen Druckbedingungen und unter inerter Abdeckung. Damit wird der für eine industrielle Fertigung, insbesondere für Industrieroboter, notwendige Freiheits‐ und Zugänglichkeitsgrad zur Fügestelle im Vergleich zu konventionellen geschlossenen WIG‐Schweißhauben gewährleistet. Von weitgehender Bedeutung für die Schweißtechnik von Titanwerkstoffen ist es, dass auch die Bereiche, die in der Praxis mittels einer Nachschleppdüse vom Schutzgas nicht erreichbar wären, wie z. B. die Überlappgebiete bei der Überlappnaht, erfolgreich durch das Prinzip der wirbelfreien Schweißkammer geschützt werden können.Mit Hilfe dieser neuartigen Vorgehensweise und eines modernen Fügeverfahrens, wie dem Nd:YAG‐Laserschweißen, konnten erstmalig systematische Grundlagenuntersuchungen zum Einfluss von Sauerstoff in der Schweißumgebung auf die Mikrostruktur und auf die mechanisch‐technologischen Eigenschaften einer Modellschweißverbindung durchgeführt werden.Durch die Validierung des gesamten Systems konnte bewiesen werden, dass im Vergleich zum konventionellen WIG‐Verfahren geringere Anforderungen an die Reinheit des Schutzgases, um Anlauffarben und unzulässige Aufhärtungen zu vermeiden, gerichtet werden können. Für das Laserstrahlschweißen kann ein maximaler Restsauerstoffgehalt von 1000 ppm in der Schweißumgebung unbedenklich toleriert werden. Für das WIG‐Schweißen gilt dagegen ein Höchstwert von etwa 30 ppm.Ferner konnte nachgewiesen werden, dass die Qualitätsmerkmale der derzeitigen Regelwerke für das WIG‐Schweißen für die Luft‐ und Raumfahrttechnik auf das Verfahren Laserstrahlschweißen mit Nd:YAG‐Quellen übertragen werden können.
Histological and microradiographic appearances of Silicon Nitride and Aluminum Oxide in a rabbit femur implantation model*
Authors: Neumann A. , Kramps M. , Ragoß Chr. , Maier H.R. , Jahnke K. 
Published: August 2004

AbstractSilicon nitride (Si3N4) is a ceramic known for its high performance characterized by fracture toughness, high wear resistance and low coefficient of friction. It has therefore been considered as a biomaterial especially for orthopaedic and dental indications. There is a controversy concerning the biocompatibility among the limited number of authors dealing with this material. Own investigations, applying the L929‐fibroblast cell culture model revealed good biocompatibilty. The aim of this study is to verify these findings in the animal model. 36 cylinders of Si3N4 and the established biomaterial aluminum oxide (Al2O3) were implanted “press fit” into the lateral condyli of the femurs of 6 New Zealand white male rabbits (three implants per condylus, materials randomized). The right femur of each animal was prepared for microradiographs and grounded sections, the left for histological sections, respectively. Animals were divided into 2 groups with 3 rabbits each. One group was sacrificed after a period of 4 weeks and the other after 8 weeks. Morphometric assessment of bone‐implant attachment was performed using a digital image analyzing system. Percentages of bone‐implant attachment ranged from 44 to 82 %. There was no statistically different percentage of bone‐implant attachment between Al2O3 and Si3N4 after 4 and 8 weeks, except in the histological section after 8 weeks of implantation. During the period of 4 to 8 weeks after implantation there was no significant decrease of bone‐implant contact except for Al2O3 in the histological sections. No local or generalized immuno‐inflammatory reactions were observed. The lamellar bone in direct contact to the materials showed no histological evidence of round cell infiltration or giant cell reactions. Our investigations suggest that Si3N4 shows good biocompatibility and presumably even better osseointegration than Al2O3.
Boiling of the Chemical Elements
Authors: Hoffmann H.‐J. 
Published: August 2004

AbstractThe molar boiling entropy, ΔSboil, has been assumed in the literature to be approximately the same for one‐component systems, which is known as the rule of Pictet‐Trouton. Using experimental data on ΔSboil of the chemical elements, however, this rule must be questioned. Instead, the increase of the molar entropy upon boiling is estimated from the expansion of the melt to the volume of the vapour under atmospheric pressure. This yields the right order of magnitude for ΔSboil.The molar boiling entropy depends on the number of electrons in the outermost electron shell of the free atoms of the chemical elements. Thus, the electronic system stores some entropy needed for boiling and seems to cause the phase transition liquid/vapour. This is supported by the correlation between the electron configuration and the molar specific heat capacities in the liquid and the vapour state near the boiling temperature. Accordingly, boiling is induced by electronic transitions into anti‐bonding states at a rate sufficient to increase the partial pressure of the vapour within a melt. This is in contrast to the traditional explanation of boiling by breaking pair bonds between the atomic constituents of a melt which neglects the effect of transitions of the bonding electrons.
Ermittlung des Festigkeits‐ und Schädigungsverhaltens von Airbaggewebe bei verschiedenen Belastungszuständen und Dehnraten
Authors: Rohr I. , Harwick W. , Nahme H. 
Published: August 2004

AbstractIn dieser Veröffentlichung wird das Materialverhalten eines typischen Airbaggewebes aus Polyamid 6.6 bei verschiedenen Belastungszuständen und Dehnraten untersucht. Wesentliche Ergebnisse sind dabei eine nahezu lineare Abnahme der Versagensspannung und eine lineare Zunahme der Versagensdehnung mit steigender Temperatur.Ein weiterer wichtiger Materialparameter für die Charakterisierung von Airbaggeweben, der Berstdruck bei dem das Material versagt, wurde im hier vorliegenden Fall zu 4‐5 bar gemessen. Die gemessen Materialdaten sind von unmittelbarer Bedeutung bei der Auslegung von Airbags.
Gene expression microarray analysis and genome databases facilitate the characterization of a chromosome 22 derived homogenously staining region
Authors: Arcand Suzanna L. , Mes‐Masson Anne‐Marie , Provencher Diane , Hudson Thomas J. , Tonin Patricia N. 
Published: August 2004

AbstractKaryotype and fluorescence in situ hybridization (FISH) analyses previously identified a homogenously staining region (HSR) derived from chromosome 22 in OV90, an epithelial ovarian cancer (EOC) cell line. Affymetrix® expression microarrays in combination with the UniGene and Human Genome Browser databases were used to identify the candidate genes comprising the amplicon of the HSR, based on comparison of expression profiles of OV90, EOC cell lines lacking HSRs and primary cultures of normal ovarian surface epithelial (NOSE) cells. A group of probe sets displaying a minimum 3‐fold overexpression with a high reliability score (P‐call) in OV90 were identified which represented genes that mapped within a 1–2 Mb interval on chromosome 22. A large number of probe sets, some of which represent the same genes, displayed no evidence of overexpression and/or low reliability scores (A‐call). An investigation of the probe set sequences with the Affymetrix® and Sanger Institute Chromosome 22 Group databases revealed that some of the probe sets displaying discordant results for the same gene were complementary to intronic sequences and/or the antisense strand. Microarray results were validated by RT‐PCR. Genomic analysis suggests that the HSR was derived from the amplification of a 1.1 Mb interval defined by the chromosomal map positions of ZNF74 and Hs.372662, at 22q11.21. The deduced amplicon is derived from a complex region of chromosome 22 that harbors low‐copy repeats (LCRs). The amplicon contains 18 genes as likely targets for gene amplification. This study illustrates that large‐scale expression microarray analysis in combination with genome databases is sufficient for deducing target genes associated with amplicons and stresses the importance of investigating probe set design before engaging in validation studies. © 2004 Wiley‐Liss, Inc.
Using DNA microarray analyses to elucidate the effects of genistein in androgen‐responsive prostate cancer cells: Identification of novel targets
Authors: Takahashi Yoko , Lavigne Jackie A. , Hursting Stephen D. , Chandramouli Gadisetti V.R. , Perkins Susan N. , Barrett J. Carl , Wang Thomas T.Y. 
Published: August 2004

AbstractMany studies have correlated the consumption of soy‐rich diets with a decreased risk of developing hormone‐dependent cancers, including prostate cancer. Genistein is a candidate prostate cancer preventive phytochemical found at high levels in soybean and soy foods. To better understand the molecular mechanisms underlying the beneficial effects of genistein on prostate cancer prevention, we used a DNA microarray approach to examine the effects of genistein at concentrations in the physiologic range on global gene expression patterns in androgen‐responsive cancer cells. Microarray analyses were performed on androgen‐responsive LNCaP human prostate cancer cells exposed to 0, 1, 5, or 25 μM genistein. We found a concentration‐dependent modulation of multiple cellular pathways that are important in prostate carcinogenesis. Interestingly, the androgen receptor (AR)‐mediated pathways, in particular, appeared to be modulated by genistein at the lowest concentrations. Based on these results, we propose that the regulation of AR‐mediated pathways is potentially the most relevant chemopreventive mechanism for genistein administered at physiologic levels. Published 2004 Wiley‐Liss, Inc.
Gene expression in the bladder carcinoma rat model
Authors: Ariel Ilana , Ayesh Suhail , Gofrit Ofer , Ayesh Basim , Abdul‐Ghani Rula , Pizov Galina , Smith Yoav , Sidi Ami A. , Birman Tatiana , Schneider Tamar , Groot Nathan de , Hochberg Abraham 
Published: August 2004

AbstractWe investigated gene expression in N‐butyl‐N‐(4‐hydroxybutyl)nitrosamine (BBN)‐induced rat bladder carcinoma in order to test its applicability as a model for the study of novel therapeutic modalities, particularly gene therapy. We administered BBN in the drinking water to Wistar rats for up to 30 wk and induced papillary transitional cell carcinoma (TCC), which is similar to the most prevalent type of human bladder cancer. Tumor evolution was similar to that found in previous studies. However, we described the morphological stages according to modern human bladder carcinoma terminology. Our main goal was to examine the expression levels of the H19 gene, of the insulin‐like growth factor 2 (Igf2) transcripts expressed from promoters P2 and P3 and of the telomerase subunits that we had previously investigated as tools for targeted gene therapy of bladder cancer. We detected at 30 wk of BBN exposure significant upregulation of these sequences in the rat bladder tumors, similar to our previous findings in human bladder cancer. To reinforce the similarity of this model to the corresponding human disease, we searched for additional tumor‐specific genes documented as having altered expression in human bladder carcinoma, using cDNA expression arrays (Clontech™). We suggest that BBN‐induced rat bladder cancer has morphological, biological, and molecular parallels to human bladder cancer and is an attractive model for studying novel alternatives of therapeutic intervention. © 2004 Wiley‐Liss, Inc.
Differences in ornithine decarboxylase and androgen receptor allele frequencies among ethnic groups
Authors: O'Brien Thomas G. , Guo Y. , Visvanathan K. , Sciulli J. , McLaine M. , Helzlsouer K.J. , Watkins‐Bruner D. 
Published: August 2004

AbstractRecent evidence suggests that the A allele of the ornithine decarboxylase (ODC) gene is a genetic risk factor for prostate cancer. ODC is a target gene of the highly polymorphic androgen receptor (AR) gene, short alleles of which have been associated in some studies with increased prostate cancer risk. We determined ODC allele frequencies and distribution of AR alleles in American Caucasians, African‐Americans, Hispanics, Europeans, and Africans. The frequency of the ODC A allele varied from 0.183 (Hispanics, Europeans) to 0.415 (Africans) with American Caucasian and African‐Americans having intermediate values. The mean number of CAG repeats in the AR gene varied from 19.8 (African‐Americans) to 25.1 (Hispanics). It is possible that ethnic differences in risk alleles for ODC and AR may account for some of the ethnic variation in prostate cancer risk. © 2004 Wiley‐Liss, Inc.
Adult‐onset generalized dystonia due to a mutation in the neuroferritinopathy gene
Authors: Mir Pablo , Edwards Mark J. , Curtis Andrew R.J. , Bhatia Kailash P. , Quinn Niall P. 
Published: August 2004

AbstractNeuroferritinopathy is a recently recognized autosomal dominant disorder that results in abnormal aggregates of iron and ferritin in the brain due to a mutation in the ferritin light chain gene on chromosome 19q13.3. We present the clinical details of a patient with adult‐onset generalized dystonia associated with this mutation. Neuroferritinopathy appears to be a rare disorder; hence, there is a need to report new cases to further our understanding of the clinical phenotype, diagnostic challenges, the course of the condition and imaging characteristics. © 2004 Movement Disorder Society
Prevalence and clinical features of hedonistic homeostatic dysregulation in Parkinson's disease
Authors: Romana Pezzella Francesca , Colosimo Carlo , Vanacore Nicola , Di Rezze Simone , Chianese Melania , Fabbrini Giovanni , Meco Giuseppe 
Published: August 2004

AbstractHedonistic homeostatic dysregulation (HHD) is a neuropsychiatric disorder recently described in Parkinson's disease (PD), which is characterized by self‐medication and addiction to dopaminergic drugs. To understand the prevalence of this disorder, we screened 202 PD patients attending our movement disorder unit for HHD. The clinical features of the patients identified as affected by this syndrome were then compared with those of control PD patients in an attempt to ascertain the possible risk factors for HHD. Results showed 7 subjects who fulfilled the HHD criteria. The analysis of a case–control study showed a significant correlation between HHD and a previous history of mood disorders, and the use of dopamine agonists, either in monotherapy or in combination. The prevalence of HHD in our study is similar to the one reported in the United Kingdom by the authors who first described this syndrome in PD. Of interest, our patients showed a somewhat different pattern of the disorder, suggesting that cultural and environmental factors may play a role in the phenomenology of HHD. © 2004 Movement Disorder Society
Proactive release procedures for just‐in‐time job shop environments, subject to machine failures
Authors: Bollapragada Ramesh , Sadeh Norman M. 
Published: August 2004

AbstractIn this paper, we consider just‐in‐time job shop environments (job shop problems with an objective of minimizing the sum of tardiness and inventory costs), subject to uncertainty due to machine failures. We present techniques for proactive uncertainty management that exploit prior knowledge of uncertainty to build competitive release dates, whose execution improves performance. These techniques determine the release dates of different jobs based on measures of shop load, statistical data of machine failures, and repairs with a tradeoff between inventory and tardiness costs. Empirical results show that our methodology is very promising in comparison with simulated annealing and the best of 39 combinations of dispatch rules & release policies, under different frequencies of breakdowns. We observe that the performance of the proactive technique compared to the other two approaches improves in schedule quality (maximizing delivery performance while minimizing costs) with increase in frequency of breakdowns. The proactive technique presented here is also computationally less expensive than the other two approaches. © 2004 Wiley Periodicals, Inc. Naval Research Logistics, 2004
Due‐window assignment with unit processing‐time jobs
Authors: Mosheiov Gur , Oron Daniel 
Published: August 2004

AbstractIn due‐window assignment problems, jobs completed within a designated time interval are regarded as being on time, whereas early and tardy jobs are penalized. The objective is to determine the location and size of the due‐window, as well as the job schedule. We address a common due‐window assignment problem on parallel identical machines with unit processing time jobs. We show that the number of candidate values for the optimal due‐window starting time and for the optimal due‐window completion time are bounded by 2. We also prove that the starting time of the first job on each of the machines is either 0 or 1, thus introducing a fairly simple, constant‐time solution for the problem. © 2004 Wiley Periodicals, Inc. Naval Research Logistics, 2004