bluuebunny/crossref_metadata_2025_split huggingface dataset:
Contributions to the Experimental Investigation of the Nascent Polymerisation of Ethylene on Supported Catalysts, 2
Authors: Di Martino Audrey , Weickert Guenter , McKenna Timothy F.L. 
Published: February 2007

AbstractA series of experiments in a novel quench flow reactor was used to study the influence of the means of adding TEA to the catalyst, the reaction temperature and the hydrogen concentration on the kinetics and morphology of the nascent phase of the polymerisation of ethylene in heptane slurry. It was shown that regardless of the way in which the alkyl was added, an extremely rapid reaction rate was observed for the first few fractions of a second, but that precontacting the catalyst and the TEA cocatalyst led to a slightly higher initial rate. On the other hand, the nascent morphology of the particle/support complex was strongly influenced by the means of adding the alkyl, with precontacting of the two components leading to a better defined product. The influence of the temperature was found to be less significant; however, this was attributed to the particular catalyst.magnified image
Modeling of Nitroxide‐Mediated Semibatch Radical Polymerization
Authors: Fu Yao , Cunningham Michael F. , Hutchinson Robin A. 
Published: February 2007

AbstractA mechanistic model is developed for high‐temperature (138 °C) styrene semibatch thermally and conventionally initiated FRP, as well as NMP with a two‐component initiating system (tert‐butyl peroxyacetate, 4‐hydroxy‐TEMPO). The model, using kinetic coefficients from literature, provides a good representation of the FRP experimental results. Implementation of a gel effect correlation to represent the change in the diffusion‐controlled termination rate coefficient with conversion improves the fit to the thermally initiated system, but is not required to represent the production of low molecular weight material ($\overline M _{\rm n} < 10\,000$ Dalton) by conventionally initiated FRP or NMP. The low initiator efficiency found in NMP is well explained by a reaction network involving combination of free nitroxide with methyl radicals formed from initiator decomposition.magnified image
Myosin heavy chain–based fiber types in the adult human cricopharyngeus muscle
Authors: Mu Liancai , Su Hungxi , Wang Jun , Sanders Ira 
Published: February 2007

AbstractThe cricopharyngeus (CP) muscle is a major component of the upper sphincter of the esophagus. Its physiology is complex; a variety of reflexes maintain CP sustained contraction except during swallowing, when it relaxes to allow a food bolus to pass into the esophagus. In order to understand CP function, we previously studied the normal adult human CP and found that it has an unusual layered structure, with a slow inner and fast outer layer. In addition, a majority of its muscle fibers express unusual myosin heavy chain (MHC) isoforms (slow‐tonic, α‐cardiac, neonatal, and embryonic) as well as the major MHC isoforms (types I, IIa, and IIx). In this study, autopsied adult human CP muscles were studied with immunocytochemical techniques to determine the patterns of MHC coexpression in CP muscle fibers. The results show that CP fibers were hybrids expressing from two to six MHC isoforms. Ten different combinations of MHC isoforms were identified in CP fibers, with the most common (54%) containing three MHC isoforms. The variety of hybrid CP fiber types suggests that the CP is capable of a wide range of contraction characteristics. Determination of MHC expression patterns of the CP muscle fibers is critical for evaluating the contractile properties of the sphincter. Muscle Nerve, 2007
The electromyographic diagnosis of amyotrophic lateral sclerosis: Does the evidence support the El Escorial criteria?
Authors: Makki Achraf A. , Benatar Michael 
Published: February 2007

AbstractThe aim of this retrospective cohort study was to examine the accuracy of the El Escorial electromyographic criteria for the diagnosis of amyotrophic lateral sclerosis (ALS). Based on a consecutive series of 73 patients with suspected ALS, the sensitivity of electromyography (EMG) ranged from 0.2 in the cranial segment to 0.74 in the thoracic segment. Specificity was highest (0.92–1.0) in the cranial and thoracic segments. Using receiver operating characteristic (ROC) curve analysis to examine the effect of varying the number of abnormal segments required for the diagnosis, we found an overall accuracy of 0.90 and 0.87 if one or two abnormal segments, respectively, were required. The best combination of sensitivity and specificity was achieved by requiring EMG changes in two segments with abnormalities in a single muscle in the cranial and thoracic segments, but abnormalities in two muscles in the cervical and lumbosacral regions. These findings lend support to the EMG criteria proposed at El Escorial. Muscle Nerve, 2007
Time to failure of a sustained contraction is predicted by target torque and initial electromyographic bursts in elbow flexor muscles
Authors: Rudroff Thorsten , Christou Evangelos A. , Poston Brach , Bojsen‐Møller Jens , Enoka Roger M. 
Published: February 2007

AbstractThe purpose of the study was to identify factors that could predict differences among individuals in the time to failure of a submaximal contraction. Twenty subjects (10 men, 25 ± 6 years) supported an inertial load equivalent to 20% of the maximal voluntary contraction (MVC) force with the elbow flexor muscles for as long as possible. The time to failure was predicted by the frequency of electromyographic bursts in the long head of biceps brachii during the first 20% of the contraction, the amplitude of bursts in the brachioradialis during the first 20% of the contraction, and the target torque. Subjects who could sustain the task longer exhibited greater initial (first 20% of contraction) electromyographic burst frequency in the long head of biceps brachii, lower initial burst amplitudes in the brachioradialis muscle, and lower target torque. Knowing the main predictors of a submaximal fatiguing contraction with the elbow flexor muscles may assist clinicians in personalizing therapeutic interventions. Muscle Nerve, 2007
A mixed augmented Lagrangian‐extended finite element method for modelling elastic–plastic fatigue crack growth with unilateral contact
Authors: Elguedj T. , Gravouil A. , Combescure A. 
Published: February 2007

AbstractThe complete modelling of fatigue crack growth is still an industrial challenging issue for numerical methods. A new technique for the finite element modelling of elastic–plastic fatigue crack growth with unilateral contact on the crack faces is presented. The extended finite element method (X‐FEM) is used to discretize the equations, allowing for the modelling of arbitrary cracks whose geometries are independent of the finite element mesh. This paper presents an augmented Lagrangian formulation in the X‐FEM framework that is able to deal with elastic–plastic crack growth with treatment of contact. An original formulation, which takes advantages of two powerful numerical methods, is presented. Next the numerical issues such as contact treatment and numerical integration are addressed, and finally numerical examples are shown to validate the method. Copyright © 2007 John Wiley & Sons, Ltd.
Endothelial cell KIT expression in human tumours
Authors: Sihto H , Tynninen O , Bützow R , Saarialho‐Kere U , Joensuu H 
Published: February 2007

AbstractReceptor tyrosine kinases expressed in endothelial cells are potential targets for therapy with specific tyrosine kinase inhibitors. Endothelial cell KIT expression has not been systematically evaluated in human cancer. In the present study, endothelial cell KIT expression was assessed in 345 tumours consisting of 34 different histological types using a tissue microarray technique. Marked KIT expression occurred in the tumour endothelial cells only in primary glioblastomas in the microarray. Moderate to strong KIT and phosphorylated KIT expression was detected in the tumour endothelial cells in six (16%) and seven (19%) of the 37 primary glioblastomas examined, respectively. In whole tissue sections, KIT and phosphorylated KIT were expressed in tumour endothelial cells in 13 (59%) and 11 (50%) of the 22 glioblastomas examined, respectively. RNA in situ hybridization showed KIT mRNA expression in most glioblastomas both in tumour vessel endothelial cells and in perinecrotic palisading glioblastoma cells, whereas little KIT mRNA was found in the endothelial cells of colon or pancreatic carcinomas. Phosphorylated KIT, its ligand stem cell factor, and the downstream signalling molecules phosphorylated Akt and mTOR were often expressed in glioblastoma cells located in the perinecrotic tumour areas that often also contained abundant HIF‐1α. It is concluded that marked KIT and phosphorylated KIT expression is frequently present in the endothelial cells of glioblastomas, which are known to harbour florid microvascular proliferation with characteristic morphological features. Glioblastomas also express phosphorylated KIT and its activated downstream signalling molecules in the tumour cells. Lower levels of KIT and phosphorylated KIT are present in endothelial cells of other tumour types and in normal tissues. Endothelial cell and tumour cell expression of activated KIT might explain in part the responsiveness of glioblastomas to the combination of imatinib (an inhibitor of KIT) and hydroxyurea. Copyright © 2007 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Model competencies in regulatory therapeutic product assessment: Health Canada's good review guiding principles as a reviewing community's code of intellectual conduct
Authors: Lim Robyn R. 
Published: February 2007

AbstractPurposeThis article describes some work from the Therapeutic Products Directorate of Health Canada regarding Good Review Practices (GRP).Methods and ResultsBackground information is provided on the Therapeutic Products Directorate (TPD) and its regulatory activities regarding drug and medical device assessment in both the pre‐ and post‐market setting. The TPD Good Review Guiding Principles (GRGP) are described which include a Definition of a Good Therapeutic Product Regulatory Review, Ten Hallmarks of a Good Therapeutic Product Regulatory Review and Ten Precepts. Analysis of the guiding principles discusses possible linkages between the guiding principles and intellectual virtues.ConclusionsThrough this analysis an hypothesis is developed that the guiding principles outline a code of intellectual conduct for Health Canada's reviewers of evidence for efficacy, safety, manufacturing quality and benefit‐risk regarding therapeutic products. Opportunities to advance therapeutic product regulatory review as a scientific discipline in its own right and to acknowledge that these reviewers constitute a specific community of practice are discussed. Integration of intellectual and ethical approaches across therapeutic product review sectors is also suggested. Copyright © 2007 Crown in the right of Canada. Published by John Wiley & Sons, Ltd.
Catalysis by hydrogen chloride in the gas‐phase elimination kinetics of 2‐phenyl‐2‐propanol and 3‐methyl‐1‐buten‐3‐ol
Authors: Rasse Rafael J. , Domínguez Rosa M. , Herize Armando , Tosta Maria , Brusco Doris , Chuchani Gabriel 
Published: February 2007

AbstractA homogeneous, molecular, gas‐phase elimination kinetics of 2‐phenyl‐2‐propanol and 3‐methyl‐1‐ buten‐3‐ol catalyzed by hydrogen chloride in the temperature range 325–386 °C and pressure range 34–149 torr are described. The rate coefficients are given by the following Arrhenius equations: for 2‐phenyl‐2‐propanol log k1 (s−1) = (11.01 ± 0.31) − (109.5 ± 2.8) kJ mol−1 (2.303 RT)−1 and for 3‐methyl‐1‐buten‐3‐ol log k1 (s−1) = (11.50 ± 0.18) − (116.5 ± 1.4) kJ mol−1 (2.303 RT)−1. Electron delocalization of the CH2CH and C6H5 appears to be an important effect in the rate enhancement of acid catalyzed tertiary alcohols in the gas phase. A concerted six‐member cyclic transition state type of mechanism appears to be, as described before, a rational interpretation for the dehydration process of these substrates. Copyright © 2007 John Wiley & Sons, Ltd.
Syntheses and characterization of 16‐arm star and star diblock copolymer and AB8 9‐miktoarm star copolymer via NMRP and ROP from dendritic multifunctional macroinitiators
Authors: Miura Yozo , Dote Hiroyuki , Kubonishi Hiroyuki , Fukuda Kenichi , Saka Tomoko 
Published: February 2007

AbstractA dendritic macroinitiator having 16 TEMPO‐based alkoxyamines, Star‐16, was prepared by the reaction of a dendritic macroinitiator having eight TEMPO‐based alkoxyamines, [G‐3]‐OH, with 4,4′‐bis(chlorocarbonyl)biphenyl. The nitroxide‐mediated radical polymerization (NMRP) of styrene (St) from Star‐16 gave 16‐arm star polymers with PDI of 1.19–1.47, and NMPR of 4‐vinylpyridine from the 16‐arm star polymer gave 16‐arm star diblock copolymers with PDI of 1.30–1.43. The ring‐opening polymerization of ε‐caprolactone from [G‐3]‐OH and the subsequent NMRP of St gave AB8 9‐miktoarm star copolymers with PDI of 1.30–1.38. The benzyl ether linkages of the 16‐arm star polymers and the AB8 9‐miktoarm star copolymers were cleaved by treating with Me3SiI, and the resultant poly(St) arms were investigated by size exclusion chromatography (SEC). The SEC results showed PDIs of 1.23–1.28 and 1.18–1.22 for the star polymers and miktoarm stars copolymers, respectively, showing that they have well‐controlled poly(St) arms. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1159–1169, 2007.
Solvothermal Route to Synthesize Well‐Dispersed YBO3:Eu Nanocrystals
Authors: Li Zhihua , Zeng Jinghui , Li Yadong 
Published: February 2007

AbstractWell‐dispersed YBO3:Eu nanocrystals have been fabricated by a solvothermal method. The size and morphology of the products are controlled successfully via adjusting the reaction conditions. The prepared YBO3:Eu phosphors were characterized by powder X‐ray diffraction, transmission electron microscopy, and other techniques. The luminescence mechanism and the size dependence of their fluorescence properties are also explained.
The Synergism Effect Between Sodium Dodecylbenzene Sulfonate and a Block Copolymer in Aqueous Solution
Authors: Azzam E. M. S. 
Published: February 2007

AbstractThe synergistic behavior of sodium dodecylbenzene sulfonate (SDBS) with poly(ethylene oxide)–poly(propylene oxide)–poly(ethylene oxide) (PEO–PPO–PEO) block copolymer was studied using surface tension measurements. The surface tension of single and mixed solutions of SDBS and the block copolymer in this study was measured at different concentrations and at 25 °C. The critical micelle concentration (CMC) of these solutions was determined from the surface tension measurements. The SDBS gives higher CMC values than those of the block copolymer. The results show that the CMC value of SDBS decreases as the molar ratio of SDBS increases in the mixture solution with the block copolymer. The surface parameters of adsorption and micellization for single and mixed solutions were investigated. The results show that the surface and micellization properties of SDBS were improved as a result of mixing with the block copolymer. The mole fractions in the micelles and interaction parameters of the mixed solutions were calculated. The foam stability of single and mixed solutions at 25 °C was determined. The results show that the SDBS has more foam stability than the block copolymer and the foam stability increases as the molar ratio of SDBS increase in mixed solution of it with block copolymer.
Fatty acid production in Schizochytrium sp.: Involvement of a polyunsaturated fatty acid synthase and a type I fatty acid synthase
Authors: Hauvermale A. , Kuner J. , Rosenzweig B. , Guerra D. , Diltz S. , Metz J. G. 
Published: February 2007

AbstractSchizochytrium sp. is a marine microalga that has been developed as a commercial source for docosahexaenoic acid (DHA, C22∶6 ω−3), enriched biomass, and oil. Previous work suggested that the DHA, as well as docosapentaenoic acid (DPA, C22∶5 ω−6), that accumulate in Schizochytrium are products of a multi‐subunit polyunsaturated fatty acid (PUFA) synthase (1). Here we show data to support this view and also provide information of other aspects of fatty acid synthesis in this organism. Three genes encoding subunits of the PUFA synthase were isolated from genomic DNA and expressed in E. coli along with an essential accessory gene encoding a phosphopantetheinyl transferase (PPTase). The resulting transformants accumulated both DHA and DPA. The ratio of DHA to DPA was approximately the same as that observed in Schizochytrium. Treatment of Schizochytrium cells with certain levels of cerulenin resulted in inhibition of 14C acetate incorporation into short chain fatty acids without affecting labeling of PUFAs, indicating distinct biosynthetic pathways. A single large gene encoding the presumed short chain fatty acid synthase (FAS) was cloned and sequenced. Based on sequence homology and domain organization, the Schizochytrium FAS resembles a fusion of fungal FAS β and α subunits.
Different kinetic in incorporation and depletion of n−3 fatty acids in erythrocytes and leukocytes of mice
Authors: Mu H. , Thøgersen R. L. , Maaetoft‐Udsen K. , Straarup E. M. , Frøkiær H. 
Published: February 2007

Abstractn−3 PUFA are well known for their anti‐inflammatory effects. However, there has been only limited study on the kinetics of incorporation and depletion of n−3 PUFA in immune cells. In the present study we investigated the incorporation and depletion of n−3 PUFA in erythrocytes and leukocytes in mice during a 6‐wk feeding period. Over the first 3‐wk period (the incorporation period) the mice were fed a special diet with a high n−3/n−6 PUFA ratio. In the following 3‐wk period (the depletion period) the mice were fed a standard chow diet. A linear incease of the concentration of EPA and DHA in erythrocyte membranes was observed during the incorporation period, whereas a stagnation was observed after the second week for leukocytes. The level of EPA did not fall to the background level after the depletion period, and the level of DHA was kept almost constant during the depletion period in the erythrocyte membranes. In leukocytes the concentration of both EPA and DHA decreased during the depletion period, but did not reach the background level after the 3‐wk depletion. In conclusion, the kinetics of EPA and DHA in the different cells are different. The rate of incorporation is faster than that of depletion for n−3 PUFA. More n−3 PUFA can be incorporated into leukocytes in comparison with erythrocytes. The ratio of n−3/n−6 PUFA is more important than the amount of n−3 FA in changing the FA compositions of membrane lipids.
Antioxidant effects of black rice extract through the induction of superoxide dismutase and catalase activities
Authors: Chiang An‐Na , Wu Hua‐Lin , Yeh Hung‐I , Chu Chi‐Shuen , Lin Hui‐Chiao , Lee Wei‐Chin 
Published: February 2007

AbstractOur ex vivo study revealed that BRE had significantly stronger ability to inhibit LDL oxidation than white rice extract (WRE). The purpose of this study was to investigate whether black rice extract (BRE) supplementation might ameliorate oxidative stress and enhance antioxidant enzyme activities in HepG2 cells and in C57BL/6 mice. In the cellular study, superoxide anions (O2.−) and reactive oxygen species (ROS) in the BRE group were significantly suppressed. The BRE group also showed significant increases in superoxide dismutase (SOD) and catalase (CAT) activities by 161.6% and 73.4%, respectively. The major components responsible for the free‐radical‐scavenging and antioxidative properties might be cyanidin−3‐O‐glucoside chloride and peonidin‐3‐O‐glucuside chloride. In the animal study, male C57BL/6 mice were divided into three groups (control, BRE, and WRE). Plasma HDL‐cholesterol was significantly higher, and thiobarbituric, acid‐reactive substances were significantly lower in the BRE group, whereas plasma levels of total cholesterol and triglyceride were not affected by BRE supplementation. Increased hepatic SOD and CAT activities were observed in BRE‐treated mice as compared to the control mice. However, no changes were detected for the protein expression of antioxidant enzymes by Western blot analysis. Our data suggest that antioxidative effects exerted by BRE are mediated through decreases in free‐radical generation as well as increases in SOD and CAT activities both in vitro and in vivo.
Lymphatic recovery of exogenous oleic acid in rats on long chain or specific structured triacylglycerol diets
Authors: Vistisen Bodil , Mu Huiling , Høy Carl‐Erik 
Published: February 2007

AbstractSpecific structured triacylglycerols, MLM (M=medium‐chain fatty acid, L=long‐chain fatty acid), rapidly deliver energy and long‐chain fatty acids to the body and are used for longer periods in human enteral feeding. In the present study rats were fed diets of 10 wt% MLM or LLL (L=oleic acid [18∶1n−9], M=caprylic acid [8∶0]) for 2 wk. Then lymph was collected 24 h following administration of a single bolus of 13C‐labeled MLM or LLL. The total lymphatic recovery of exogenous 18∶1n−9 24 h after administration of a single bolus of MLM or LLL was similar in rats on the LLL diet (43% and 45%, respectively). However, the recovery of exogenous 18∶1n−9 was higher after a single bolus of MLM compared with a bolus of LLL in rats on the MLM diet (40% and 24%, respectively, P=0.009). The recovery of lymphatic 18∶1n−9 of the LLL bolus tended to depend on the diet triacylglycerol structure and composition (P=0.07). This study demonstrated that with a diet containing specific structured triacylglycerol, the lymphatic recovery of 18∶1n−9 after a single bolus of fat was dependent on the triacylglycerol structure of the bolus. This indicates that the lymphatic recovery of long‐chain fatty acids from a single meal depends on the overall long‐chain fatty acid composition of the habitual diet. This could have implications for enteral feeding for longer periods.
Human milk fatty acid composition from nine countries varies most in DHA
Authors: Yuhas Rebecca , Pramuk Kathryn , Lien Eric L. 
Published: February 2007

AbstractMany published studies of breast milk FA composition are limited to populations from one or two countries. We aimed to examine the degree to which FA compositions vary across a number of diverse populations. Because diet and maternal adipose stores influence breast milk FA composition, differences in FA composition between groups most likely reflect habitual dietary differences. Approximately 50 breast milk samples (full breast expression) were collected from women in Australia, Canada, Chile, China, Japan, Mexico, Philippines, the United Kingdom, and the United States. The proportion of saturated FA was relatively constant among countries, with the exception of the Philippines, where levels of lauric and myristic acids were elevated (means greater than two times the mean of most other countries). Monounsaturated FA also varied little, with the exception of low levels of oleic acid in the Philippines and high levels of erucic acid in China. Although arachidonic acid (C20∶4n−6) levels were similar among all countries (means ranging from 0.36 wt% to 0.49 wt%), mean DHA (C22∶6n−3) levels ranged from 0.17 to 0.99 wt%, with the highest levels in Japanese milk and the lowest levels in Canadian and U.S. samples. The results of this study demonstrate that the proportion of saturated and monounsaturated FA are relatively constant across a large number of countries, whereas the level of some of the PUFA, especially DHA, are highly variable.