bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of sulfated β‐cyclodextrins and determination of enantiomeric purity of (1R,2S)‐ephedrine by capillary zone electrophoresis
Authors: Amini Ahmad , Rundlöf Torgny , Grön Rydberg May‐Britt , Arvidsson Torbjörn
Published: August 2004

Matrix‐assisted laser‐desorption ionization time‐of‐flight (MALDI–TOF) mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy were employed to characterize two different sulfated β‐cyclodextrins (HS‐β‐CD). It was found that the HS‐β‐CDs have broad heterogeneity in terms of sulfation degree. The average sulfate contents were in the range of 6 to 8 per CD molecule. Furthermore the sugar moieties of both HS‐β‐CDs were sulfated either at position 6 or at positions 2 and 6, but not at position 3. Enantiomeric separation by capillary zone electrophoresis (CZE) using the HS‐β‐CDs as chiral selectors showed that these CDs exhibited similar chiral selectivity and resolution of the ephedrine enantiomers. One of the CDs was employed for the enantiomeric purity evaluation of (1R,2S)‐ephedrine (or (–)‐ephedrine) by capillary zone electrophoresis. Quantification was done by comparison between the corrected peak areas of the minor enantiomer and (–)‐ephedrine.
Structural Aspects of Poly(thiodiethylene terephthalate) Investigated by X‐Ray Powder Diffraction
Authors: Fichera Anna Maria , Finelli Lara , Gazzano Massimo , Lotti Nadia , Malta Viscardo , Munari Andrea
Published: August 2004

Summary:The full‐profile refinement of X‐ray diffraction patterns was used to investigate two poly(thiodiethylene terephthalate) (PSDET) samples with different thermal history in order to thoroughly analyze their polymorphic aspects. In each sample, a crystalline (αorβ) and a microcrystalline (α′ orβ′) phase were identified together with an amorphous component. The crystal structures of all the ordered phases were determined. The data indicated an appreciable difference between the two crystalline forms, while the microcrystalline were rather similar. The results reported in this paper agree with the hypothesis that the polymorphic and morphological aspects of PSDET have to be correlated with the order degree and reorganization of crystallites and microcrystallites.

Projection along theaaxis andcaxis ofα‐phase chain arrangement.

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Projection along theaaxis andcaxis ofα‐phase chain arrangement.
Synthesis of Helical Polyanilines Using Chondroitin Sulfate as a Molecular Template
Authors: Yuan Guo‐Li , Kuramoto Noriyuki
Published: August 2004

Summary: 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.

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Structure 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

Summary: 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.

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DSC 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

Summary: 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.

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The 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

M2 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

Im 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

Silicon 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

The 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

In 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

Karyotype 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

Many 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

We 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

Recent 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

Neuroferritinopathy 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

Hedonistic 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

In 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

In 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
Fluoxetine alters mu opiod receptor expression in obese Zucker rat hypothalamus
Authors: Churruca I. , Casis L. , Portillo M.P. , Macarulla M.T. , Záate J. , Pascual J. , Echevarría E.
Published: August 2004

The aim of the present work was to study the potential involvement of hypothalamic opiod system in the anorectic machanism of fluoxetine in obese Zucker rats, assessing the effects of chronic fluoxetine treatment on mu opiod receptor immunostaining in several hypothalamic regions. Male obese Zucker (fa/fa) rats were administered with fluoxetine (10 mg/kg; i.p.) daily for two weeks. The control group was given 0.9% NaCl solution. Regional hypothalamic immunostaining for mu opiod receptor was carried out. Fluoxetine administration increased the numbers of neural cells positively immunostained for mu opiod receptor in the hypothalamic, paraventricular, arcuate, ventromedial and suprachiasmatic nuclei, as well as the medial preoptic and lateral hypothalamic areas, without changed in dorsomedial, supraoptic and periventricular nuclei, and the lateral preoptic area. These results suggest the involvement of hypothalamic opiod system in fluoxetine‐induced anorexia in obese Zucker rats. Increased regional hypothalamic density of neural cells expressing mu opiod receptors after fluoxetine treatment could be a compensatory mechanism against a possible reduction in opiodergic tone.
Initiation of functional synapses is associated with AMPA receptor expression
Authors: Chono Koji , Shiga Hatsuki , Tojima Takuro , Ito Etsuro
Published: August 2004

In the present study, we identified the key protein that modulates the initiation of functional glutamatergic synapses in developing cortical neurons. First, we found a day in vitro that marked a critical increase in the number of functional synapses by the application of cyclic AMP, as demonstrated with Ca2+ imaging. We then examined the changes in the expression levels of proteins, which were expected to play a role in glutamatergic synapses, by the application of cyclic AMP. Our findings suggest that the expression of the α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazole proprionic acid (AMPA) receptors modulates the initiation of functional synapses in developing neurons, and that immature neurons already contain N‐methyl d‐aspartate (NMDA) receptors and presynaptic proteins such as synaptophysin.
The influence of age on the treadmill exercise‐induced c‐Fos expression in the hippocampus of rats
Authors: Kim Sang‐Ho , Kim Hong , Kim Sung‐Soo , Shin Mal‐Soon , Chang Hyun‐Kyung , Lee Taeck‐Hyun , Jang Mi‐Hyeon , Shin Min‐Chul , Lee Hee‐Hyuk , Kim Young‐Pyo , Kim Chang‐Ju
Published: August 2004

c‐Fos has been used as a neuronal activity marker. Here, we examined the influence of age on the treadmill running‐induced c‐Fos expression in rat hippocampus. Rats of exercise groups were forces to run on treadmill for 30 min. once a day for 5 consecutive days. Without exercise, c‐Fos expression was highest in 8‐week old rats. Treadmill exercise significantly enhanced the c‐Fos expression in the hippocampus of rats in all ages. In the CA region, the increase of the c‐Fos expression by treadmill exercise was highest in 4‐week old rats. In the dentate gyrus, the increase of the c‐Fos expression by treadmill exercise was highest in 62‐week old rats. The data show that age is an important factor for the regulation of the c‐Fos expression in the hippocampus and that the ability of the treadmill exercise enhancing the c‐Fos expression is dependent on age status.
Long‐term angiotensin converting enzyme inhibition dose‐dependently improves nerve conduction velocity and evoked potential latencies in streptozotocin‐diabetic rats
Authors: Manschot Sanne M. , Kappelle L.J. , Gispen W.H. , Biessels G.J.
Published: August 2004

Vascular disease probably plays an important role in the pathogenesis of cerebral complications that are associated with diabetes mellitus. Previous studies showed that treatment with the angiotensin converting enzyme‐inhibitor enalapril (24 mg/kg) prevented neurophysiological and cognitive deficits in streptozotocin diabetic rats, and improved cerebral blood flow, despite a reduction in systemic mean arterial blood pressure. The present study examined if these effects could be sustained with long‐term treatment, and if treatment with a lower dose (12 mg/kg) could prevent peripheral and central neurophysiological deficits without causing hypotension. Sciatic nerve conduction velocities were measured every three weeks after diabetes induction, until 24 weeks. Brain stem auditory (BAEP) and visual evoked potentials (VEP) were measured every three weeks from 10 weeks after diabetes induction, until 25 weeks. Nerve conduction velocity was decreased, and BAEP and VEP latencies increased in untreated diabetic rats. At the end of follow‐up 12 mg/kg enalapril partially prevented evoked potential abnormalities, but not nerve conduction deficits, whereas 24 mg/kg enalapril largely prevented deficits in nerve conduction velocity (p<0.001), as well as BAEP (p<01) and VEP latencies (p<0.05). Mean arterial blood pressure was 122 mmHg in the untreated diabetic group, 75 mmHg in the 24 mg/kg group and 112 mmHg in the 12 mg/kg group. Sustained treatment with enalapril at 24 mg/kg was associated with increased mortality, which may be related to the marked hypotension at this dosage. We conclude that long‐term treatment with enalapril at a dose of 24 mg/kg can prevent peripheral and central neurophysiological deficits in streptozotocin diabetic rats, but that adverse effects preclude sustained treatment.
Eigenvalue approximation of the biharmonic eigenvalue problem by Ciarlet‐Raviart scheme
Authors: Chen Wei
Published: August 2004

Using the technique of eigenvalue error expansion and the technique of integral identities, we derive higher order convergence rate of the eigenvalue approximation for the biharmonic eigenvalue problem based on the Ciarlet‐Raviart discretization. © 2004 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2005
A posteriori error estimates with the finite element method of lines for a Sobolev equation
Authors: Tran Thanh , Duong Thanh‐Binh
Published: August 2004

A posteriori error estimates for semidiscrete finite element methods for a nonlinear Sobolev equation are considered. The error estimates are obtained by solving local nonlinear or linear pseudo‐parabolic equations for corrections to the solution on each element. The ratios of these estimates and the true errors are proved to converge to 1, implying that the estimates can be used as indicators in adaptive schemes for the problem. Numerical results underline our theoretical results. © 2004 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2005
Reliable, goal‐oriented postprocessing for FE‐discretizations
Authors: Suttmeier F. T.
Published: August 2004

In this article we present strategies to improve the quality of adaptive FE‐approximations measured in terms of linear functionals. The ideas are based on the so called dual‐weighted‐residual (DWR) approach to a posteriori error control for FE‐schemes. In more details, we exploit those parts of an underlying error representation, which are completely computable, to improve the FE‐solution. Furthermore, the remaining parts of the error identity can be estimated by well‐established a posteriori energy estimates yielding reliable error bounds for the postprocessed values. © 2004 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2005
Late relapse of osteosarcoma: Implications for follow‐up and screening
Authors: Strauss Sandra J. , McTiernan Anne , Whelan Jeremy S.
Published: August 2004

Long‐term disease‐free survival in patients with localised osteosarcoma treated in large multicentre randomised trials is over 50%. Most relapses occur early, usually within 2–3 years. Relapse after 5 years is uncommon and has been infrequently described. Eight patients with osteosarcoma treated at The London Bone and Soft Tissue Tumour Service since 1986 developed recurrence of disease after 5 years, the latest 14 years after the initial diagnosis. Five patients developed pulmonary metastases, two patients isolated bone metastases and one patient intra‐abdominal metastases. Although a second complete remission was achieved in six patients, four patients relapsed again, all with pulmonary metastases. Two patients had co‐existent brain metastases. One of those with a second recurrence has achieved a further complete remission and remains well 50 months after the most recent treatment. A second patient is disease‐free 24 months after complete excision of an isolated pulmonary metastasis and one further patient is disease‐free 6 months after chemotherapy and pneumonectomy for pleural and pulmonary metastases. Five patients have died of disease with a median survival from the date of relapse of 17 months (2–68 months). Current data looking at long‐term outcome of patients with osteosarcoma is limited. Reports of late relapse are rare as numbers are small, thus long‐term surveillance of patients is essential. It is possible that sites of relapse are more unusual, and more extensive staging may be necessary when late relapse occurs. © 2004 Wiley‐Liss, Inc.
Effectiveness of fixed 50% nitrous oxide oxygen mixture and EMLA cream for insertion of central venous catheters in children
Authors: Abdelkefi Abderrahman , Abdennebi Yosr Ben , Mellouli Fethi , Othman Tarek Ben , Torjman Lamia , Ladeb Saloua , Aouf Sami , Béjaoui Mohamed , Abdeladhim Abdeladhim Ben
Published: August 2004

Background

Although the equimolecular mixture of oxygen and nitrous oxide (EMONO) seems a good choice to relieve procedure‐related pain in children, it has not been evaluated for insertion of central venous catheters in children. To assess the safety and the effectiveness of this gas mixture for insertion of central venous catheters, we conducted a prospective observational study.

Procedure

This study was performed by the “Centre National de Greffe de Moelle Osseuse.” Procedure and inhalation characteristics, as well as pain evaluations and side effects, were reported.

Results

Fifty central venous catheters were inserted in 50 consecutive children. Median age was 7 (range, 4–13) years. An anesthesiologist was responsible for delivering EMONO, and provided constant surveillance throughout the procedure. EMLA cream was applied 2 hr before EMONO inhalation. No associated drugs were used. All catheters were inserted by the same experienced physician in the operating theater. Median inhalation length was 5 min (range, 3–6) before starting catheter's insertion and 12 min (range, 9–25) for the total inhalation. Median procedural pain evaluations were 10 (range, 0–30) for children on a 0–100 visual analog scale (VAS). Minor side effects were observed during eight (16%) inhalations. These side effects were euphoria (14%), deep sedation (4%), nausea and vomiting (2%), hallucinations (2%). All side effects were transient and resolved within 5 min after removing the inhalation device.

Conclusions

This study which shows that EMONO is effective for insertion of central venous catheters in children and represents a simple and safe alternative to general anesthesia. Pediatr Blood Cancer 2004;43:777–779. © 2004 Wiley‐Liss, Inc.
Drug‐induced upper gastrointestinal disorders requiring hospitalization: a five‐year study in a South Indian hospital
Authors: Devi D. Padmini , Sushma M. , Guido S.
Published: August 2004

Purpose

To study the clinical spectrum of drug induced upper gastrointestinal tract (GIT) disorders requiring hospitalization and establish the causal relation between drug and disorder using WHO causality definitions.

Methods

Case‐records of patients in the Department of Gastroenterology (from January 1998 to December 2002) hospitalized with diagnoses of drug induced upper GIT disorders were analyzed retrospectively. The causality assessment of each disorder was done based on WHO causality definitions.

Results

Out of 101 cases identified over the study period, 8 were categorized as certain, 87 as probable and 6 cases as possible. The certain and probable cases (95) were analyzed. Of these, 13 were in 1998, 14 in 1999, 18 in 2000, 20 in 2001 and 30 in 2002. The drug class most commonly implicated with adverse drug reactions was non‐steroidal anti‐inflammatory drugs (NSAIDs) (76.8%). Among individual drugs, aspirin was most commonly involved (32.6%). Results of endoscopy revealed gastric erosions (40.2%), combination of gastric ulcer and gastric erosions (16.1%), gastric ulcer (15.0%), duodenal ulcer (13.8%), normal (13.8%) and duodenal erosions (1.1%). Risk factors noticed were chronic smoking (16.8%), alcohol consumption (13.7%), smoking and alcohol use (21.1%), history of peptic ulcer (10.5%) and chronic steroid use (1.1%).

Conclusion

NSAIDs especially aspirin were implicated in maximum number of patients. An increase in occurrence over 5 years, a wide spectrum of disorders and various risk factors were noticed. Copyright © 2004 John Wiley & Sons, Ltd.
Structure and mechanical properties of polyamide‐6,6/poly(ethylene terephthalate) blends
Authors: Retolaza A. , Eguiazábal J. I. , Nazábal J.
Published: August 2004

Polyamide‐6,6 (PA)/poly(ethylene terephthalate) (PET) blends were obtained by direct injection molding over the whole composition range. Besides the two crystalline phases, the blends were composed of a pure amorphous PET phase, and a probably pure PA amorphous phase. The crystallinity of PA and PET did not change in the blends, although PA nucleated the crystallization of PET. The morphological heterogeneity was low because, although large particles were seen, they mostly contained many small (typically 0.3 μm) occlusions. This fairly homogeneous structure is attributed to the reactions observed during melt blending. The Young's modulus and yield stress of the blends followed the rule of mixtures, in good agreement with the lack of change of the crystallinity content, specific volume and orientation of the two components of the blends when they are mixed. The ductility values were also very close to those predicted by the rule of mixtures, with an absolute synergism in the 10/90 blend indicating compatibility. This positive mechanical behavior contrasts with that observed in previous works, and is attributed to the way PET crystallizes, to the highly dispersed morphology, and to the highly amorphous character of the blends obtained in this study. The ductile nature of the blends after annealing at either 80°C for one day or 100°C for 30 min indicated the considerable temperature resistance of these highly dispersed and partially reacted blends. Polym. Eng. Sci. 44:1405–1413, 2004. © 2004 Society of Plastics Engineers.
Numerical investigation of the influence of material properties and adhesive layer thickness on the heating efficiency of microwave curing of an adhesive‐bonded joint
Authors: So H. W. , Taube A.
Published: August 2004

In the process of microwave curing of an adhesive‐bonded joint, both the adhesive layer and the adherends affected the heating efficiency of the joint. As an extension of previous studies, the influences of changing the properties of the components of the joint on the heating efficiency were predicted by simulations that were based on the numerical model developed previously. The influence of adhesive thickness was also studied. The properties that directly affected power dissipation and heat loss of the adhesive layer were found to be important to the heating efficiency of the process. The heating rate was also sensitive to the thickness of the adhesive layer. Polym. Eng. Sci. 44:1414–1418, 2004. © 2004 Society of Plastics Engineers.
Thermal properties of biaxially deformed in situ composites
Authors: Seo Youngwook P. , Seo Yongsok
Published: August 2004

The thermal properties of biaxially blown poly(etherimide) (PEI) films containing a thermotropic liquid crystalline polymer (TLCP) were studied using differential scanning calorimetry, thermogravimetric analysis, wide‐angle X‐ray diffraction and dynamic mechanical thermal analysis. The effects of the compatibilizer and thermal annealing on the thermal properties of biaxially oriented TLCP films were investigated. Though the compatibilizer (poly(ester imide)) improved deformation of the TLCP phase (poly ester amide) and adhesion between the matrix and the TLCP phase, which improved mechanical properties, it did not significantly affect the thermal properties of the in situ composite films. The film degradation behavior corroborated the role of the compatibilizer. Since a relatively small amount of TLCP (10 wt%) was added to the matrix and the matrix PEI was amorphous, the effect of annealing on the TLCP structure was not obvious. By the same token, while the effect of the deformation in the circumferential direction (a change in the blow‐up ratio) was manifest in mechanical property improvements, its effect on the thermal properties was not obvious. All films showed similar thermal expansion behaviors, regardless of the thermal history and of the compatibilizer addition. Thus, there is an optimum amount of the compatibilizer required to obtain optimal mechanical properties for in situ composite films without causing a deterioration of their thermal properties. Polym. Eng. Sci. 44:1419–1428, 2004. © 2004 Society of Plastics Engineers.
Rheological, mechanical and biodegradation studies on blends of thermoplastic starch and polycaprolactone
Authors: Shin Boo‐Young , Lee Sang‐II , Shin Young‐Sub , Balakrishnan Sunder , Narayan Ramani
Published: August 2004

Polycaprolactone (PCL) has been blended with thermoplastic starch (TPS), prepared from regular corn starch and glycerol, in a twin‐screw extruder. The rheological, mechanical, thermal and morphological properties of the blends were examined. Differential Scanning Calorimetry (DSC) and Scanning Electron Microscopy (SEM) studies revealed that PCL/TPS blends are thermodynamically immiscible. However, they form compatible blends as a result of the hydrogen bonding interaction between the ester carbonyl of PCL and the OH groups on starch. Biodegradability of the blends increased with increasing TPS content. Dynamic viscoelastic measurements concluded that blends containing above 60‐wt% TPS had higher storage and loss moduli than those of pure TPS and PCL. In addition, these blends had higher complex viscosities. Polym. Eng. Sci. 44:1429–1438, 2004. © 2004 Society of Plastics Engineers.
Modeling and simulation of stretch blow molding of polyethylene terephthalate
Authors: Pham X.‐T. , Thibault F. , Lim L‐T.
Published: August 2004

When polyethylene terephthalate (PET) is stretched, it exhibits strain‐hardening properties, which are temperature and strain‐rate dependent. In this paper, two grades of PET are experimentally characterized using biaxial tests. A visco‐hyperelastic model is used to describe the stretching behavior for the polymer. A biaxial characterization method is employed to determine the model parameters using a robust nonlinear curve‐fitting program. This model can represent adequately well the stretching behavior of PET. Based on this model, the membrane finite element formulation is developed to simulate the stretch blow molding process. Two bottles of different designs, produced based on the single‐stage injection blow molding process, are used to validate the model. Good agreement with the bottle thickness profile is observed. Polym. Eng. Sci. 44:1460–1472, 2004. © 2004 Society of Plastics Engineers.
Development and characterization of reactively extruded PVC/polystyrene blends
Authors: Haba Y. , Narkis M.
Published: August 2004

PVC/PS blends are obtained through a reactive extrusion–polymerization method by the absorption of a solution of styrene monomer, initiator, and a crosslinking agent in commercial suspension‐type porous polyvinyl chloride (PVC) particles, forming a dry‐blend with a relatively high monomer content. These PVC/styrene dry‐blends are reactively polymerized in a twin‐screw extruder in the melt state. They do not contain monomer residues as detected by GC. The transparency, fracture surface morphology, thermal stability, rheology and static and dynamic mechanical properties of these blends are compared to physical PVC/PS blends at similar compositions. Owing to the high polymerization temperature (180°C), short PS chains are formed in the reactive extrusion process. These short chains are dispersed both as a separate phase of ∼2 μm particles (recognized by SEM) and also as molecularly dispersed chains enhancing plasticization and compatibilization. The molecularly dispersed short PS chains tend to plasticize the PVC phase, reducing its melt viscosity and glass transition temperature. The content of the short PS chains forming the dispersed separate PS particles is too low for DMTA to detect a separate Tg. Thus, reactively extruded PVC/PS blends exhibit single Tg transitions at lower temperatures compared with the neat PVC. Migration of the PVC's low‐molecular‐weight additives (lubricants and thermal stabilizer) to the PS phase is observed in the physical PVC/PS blends, causing antiplasticization of the PS phase. This results in both reduction of the Tg and an increase in the thermal stability of the PS phase in the physical PVC/PS blends. Comparing TGA thermograms of reactively extruded and physical PVC/PS indicates that the PS formed in the extruder is different from the commercial PS. This can stem from various chemical reactions that can take place in the studied reactive polymerization process. Polym. Eng. Sci. 44:1473–1483, 2004. © 2004 Society of Plastics Engineers.
Online measurements of crystallinity using Raman spectroscopy during blown film extrusion of a linear low‐density polyethylene
Authors: Cherukupalli Srinivas S. , Ogale Amod A.
Published: August 2004

Real‐time, Raman spectroscopic measurements of crystallinity during the blown film extrusion of a linear low‐density polyethylene (LLDPE) are reported. The take‐up ratio (TUR), inflation air pressure, and cooling conditions were varied, and their effect on the development of crystallinity was studied. The results indicate that the crystallization process starts at the freeze line, increases along the film line, and finally plateaus. It was observed that with changing processing conditions, the differences in the profiles for crystallinity were evident when plotted as a function of time rather than distance along the machine direction. The influence of take‐up ratio and bubble inflation air pressure on the development of crystallinity clearly established the role of flow‐induced crystallization during film extrusion. Polym. Eng. Sci. 44:1484–1490, 2004. © 2004 Society of Plastics Engineers.