bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biocompatibility of human osteosarcoma cells to root end filling materials
Authors: Huang Tsui Hsien , Yang Chi Chiang , Ding Sinn Jyh , Yan Min , Chou Ming Yung , Kao Chia Tze 
Published: September 2004

AbstractIdeal root end filling materials should have good physical and chemical properties, and the most important is that the material should be biocompatible with periradicular tissue. The biocompatibility of three root end filling materials, mineral trioxide aggregate, calcium hydroxide‐based cement, and eugenol‐based cement, were investigated in vitro by culturing extracts of these materials with human osteogenic sarcoma cells (U2OS). Extracts of each of the materials were made after incubation of the materials for 1 day and 1 week with complete McCoy's medium. The extracts were serially diluted and then incubated with U2OS cells for 24 and 48 h. Cell survival rates were assessed by means of a viability assay for mitochondrial dehydrogenase activity. Differences in mean cell survival rates were statistically assessed using one‐way ANOVA. Results showed that the survival rates of U2OS cells were largest with mineral trioxide aggregate, followed by calcium hydroxide‐based cement and eugenol‐based cement at 24‐ and 48‐h exposures using the 1‐day and 1‐week extracts. The duration of root end filling material extraction time and treatment time showed variable influence on the survival rates. The results suggest that mineral trioxide aggregate is more biocompatible than the other root end filling materials and is suitable for use in the clinical setting. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 72B: 140–145, 2005
Elastic modulus of resin‐based dental restorative materials: A microindentation approach
Authors: Chung S.M. , Yap A.U.J. , Tsai K.T. , Yap F.L. 
Published: September 2004

AbstractThis research aimed to determine the elastic modulus of resin‐based dental composite restoratives using the microindentation test method. Results were then compared with those obtained with the ISO three‐point bending test method. Five materials from the same manufacturer (3M ESPE) were selected for the study. They included microfill (A110), minifill (Z100 and Filtek Z250), poly‐acid modified (F2000), and flowable (Filtek Flowable [FF]) composites. The indentation moduli of the composites were determined using a custom‐designed microindentation test set up after conditioning in water at 37°C for 1 week and 1 month. The indentation test was carried out at peak load of 10Nand Oliver & Pharr's method was used to determine the maximum projected contact area. Data was analyzed using ANOVA/post‐hoc Scheffe's test at significance level 0.05 and Pearson's correlation at significance level 0.01. The mean indentation modulus ranged from 5.80 to 15.64 GPa and 5.71 to 15.35 GPa at 1 week and 1 month, respectively. At both time periods, the indentation modulus of Z100 was significantly higher than all other materials. F2000 was significantly higher than Z250, which was significantly stiffer than A110 and FF. The rankings were in good agreement with the ISO flexural test. A significant, positive, and strong correlation (r= 0.93 and 0.94 at 1 week and 1 month, respectively) in modulus between ISO three‐point bending and microindentation test methods was observed. In view of the small specimen size and good reproducibility, the microindentation reflects a potential test method for determining the elastic properties of dental composite restoratives. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 72B: 246–253, 2005
Impact of chemical oxidation on sludge properties and membrane flux in membrane separation bioreactors
Authors: Liao BQ , Catalan LJJ , Droppo IG , Liss SN 
Published: September 2004

AbstractThe effects of sodium hypochlorite (NaOCl) on sludge properties and membrane permeate flux were studied using a pressurized stirred ultrafiltration cell. Oxidation with NaOCl resulted in sludge solubilization and decreased sludge floc sizes. The sludge dissolution constant was estimated at 0.3 ± 0.1 mg sludge mg−1 free chlorine under testing conditions. The increases in soluble chemical oxygen demand and total carbohydrate concentration in centrifuged supernatant were less than proportional to chemical dosage. Membrane permeate fluxes were much lower as a result of oxidation. Soluble biopolymers accounted for more than 76% of the total hydraulic resistance during ultrafiltration of oxidized sludge. By contrast, both the settleable sludge flocs and the soluble biopolymers were important contributors to the hydraulic resistance of sludge before oxidation. Given the benefits of NaOCl solution for membrane cleaning and its negative impact on sludge properties, the quantity of NaOCl solution used for maintenance cleaning of membranes should be optimized. Copyright © 2004 Society of Chemical Industry
Preparation and characterization of UV‐grafted ion‐exchange textiles in continuous electrodeionization
Authors: Yeon Kyeong‐Ho , Song Jung‐Hoon , Kim Jung‐Bae , Moon Seung‐Hyeon 
Published: September 2004

AbstractIon‐exchange textiles (IETs) suitable for use in continuous electrodeionization (CEDI) stacks were prepared using the ultraviolet (UV)‐induced grafting of acrylic acid and sodium styrene sulfonate for cation‐exchange textiles, or 2‐hydroxyethyl methacrylate and vinylbenzyl trimethyl ammonium chloride for anion‐exchange textiles, onto nonwoven polypropylene fabric using benzophenone as photoinitiator. Although the ion‐exchange capacity (2.2 meq g−1) of the prepared strong acid cation‐exchange textile was lower than that of IRN77 strong acid cation‐exchange resin (4.2 meq g−1), the overall rate constant of IET was very high due to its low crosslinking and high specific surface area. There was no significant difference between the two different media in terms of the Co(II) removal rate. Furthermore, the current efficiency for IETs was higher than that of IRN77 cation‐exchange resin during a CEDI operation, with efficiencies of 60% and 20%, respectively. The IET also showed the faster exchange kinetics. Therefore, IETs prepared in this study proved to have desirable ion‐conducting characteristics within the CEDI systems. Also this study revealed that the primary removal mechanism in CEDI is the transport of ions through a medium and not the ionic capacity of a medium. Copyright © 2004 Society of Chemical Industry
Requirement of the N‐terminus for dimer formation of phenylalanine‐sensitive 3‐deoxy‐D‐arabino‐heptulosonate synthase AroG of Escherichia coli
Authors: Xu Jianfeng , Hu Changyun , Shen Shuiyuan , Wang Weirong , Jiang Peihong , Huang Weida 
Published: September 2004

AbstractThe first regulatory step in the synthesis of aromatic amino acids is catalyzed by 3‐deoxy‐D‐arabino‐heptulosonate 7‐phosphate synthase (DAHPS). In Escherichia coli, the allosteric DAHPS exists as three isozymes, AroG, AroF and AroH, each independently feedback‐inhibited by corresponding end product amino acids, phenylalanine, tyrosine and typtophan. Structural biological evidences have suggested that the N‐terminus of AroG is involved in the formation of a putative inhibitor‐binding site and feedback inhibition signal transmission. Our previous work showed that a single amino acid residue replacement Ile10Ala or deletion of 15 N‐terminal amino acids could lead to a dramatic loss of AroG enzymatic activity (Hu et al. 2003). Here we demonstrate that the deletion of N‐terminus prevents the enzyme from forming a dimeric structure, indicating that the N‐terminus of AroG plays a critical role in the formation of the essential tight dimeric structure. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Isolation of mak1 from Actinoplanes missouriensis and evidence that Pep2 from Streptomyces coelicolor is a maltokinase
Authors: Jarling Martin , Cauvet Thomas , Grundmeier Matthias , Kuhnert Katharina , Pape Hermann 
Published: September 2004

AbstractThe gene mak1FN coding for maltokinase from Actinoplanes missouriensis is located in a cluster similar to glycogen metabolism clusters identified in Streptomyces coelicolor. Sequence comparisons demonstrate that mak1‐related genes coding for homologous proteins are present in many bacterial genomes including taxonomic distantly related groups such as Rhodospirillales or green sulfur bacteria. More than 50% of the aligned sequences are longer than the mak1 gene from A. missouriensis, and the N‐terminal portion of these putative maltokinases exhibit high sequence homologies with trehalose synthases. A more detailed sequence comparison indicates a relationship of maltokinases to aminoglycoside phospho‐transferases and protein kinases. Transformation of S. lividans with plasmid vectors containing either the mak1 gene from A. missouriensis or the pep2 gene from S. coelicolor resulted in recombinant strains, which produced measurable amounts of maltokinase activity. The proteins Pep2 and Mak1 were over expressed with Streptomyces lividans 66 as a heterologous host and further characterized. The possible physiological function of maltokinases is discussed. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Identification of an alkaline‐tolerant cyclodextrin‐metabolizing bacterium and characterization of its cyclodextrinase gene
Authors: Kaulpiboon Jarunee , Rimphanitchayakit Vichien , Pongsawasdi Piamsook 
Published: September 2004

AbstractBacillus circulans A11, an alkaline‐tolerant cyclodextrin‐metabolizing bacterium isolated from South‐East Asian soil, was reidentified as Paenibacillus sp. A11 based on 16S rRNA gene sequence comparison, G + C content and cellular fatty acid composition. Levels of similarity of the 16S rRNA gene between strain A11 and the Paenibacillus species were 90–99%, while similarity with Bacillus circulans was only 86%. The major cellular fatty acid was anteiso‐C15:0 which accounted for 59.3% of the total cellular fatty acids and the G+C content was 50.3 mol%. The CDase gene coding for this enzyme was cloned into E. coli. The open reading frame of the CDase gene was 1,959 bp encoding a CDase of 653 amino acid residues. At maximum growth, the specific activity of the recombinant CDase from E. coli was higher than that of Paenibacillus sp. A11. By SDS‐PAGE, the translation product of the recombinant gene showed the same mobility as the purified CDase from the original strain. CDase from both Paenibacillus sp. A11 and E. coli produced glucose and maltose as dominant end‐products of β‐CD hydrolysis. The ratio of maltose to glucose was 1:2. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Cloning, characterization and phylogenetic relationships of cel5B, a new endoglucanase encoding gene from Thermobifida fusca
Authors: Posta Katalin , Béki Emese , Wilson David B. , Kukolya József , Hornok László 
Published: September 2004

AbstractThermobifida fusca, a thermophilic, aerobic, cellulolytic bacterium has a highly complex cellulase system comprising three endoglucanases, two exoglucanases and one processive endoglucanase. Zymogram analysis indicated that additional cellulases may exist in T. fusca strain TM51, therefore a TM51 expression library was prepared in Streptomyces lividans TK24 and screened for hydrolases. A new endoglucanase gene, named Tf cel5B, was identified. Heterologous Cel5B, produced in S. lividans, had temperature and pH optima of 77 °C and 8.2, respectively and retained more than 60% of its activity after 24 h incubation at 60 °C. Domain analysis revealed an N‐terminal catalytic domain with homology to known endoglucanases in family GH5 and a C‐terminal cellulose binding module III domain (CBD).Comparing the domain structures of all seven known T. fusca cellulases showed, that the cellulase system of this organism consists of pairs of enzymes from the same GH family, including Cel5A – Cel5B, Cel6A – Cel6B and Cel9A – Cel9B plus a single family GH48 enzyme (Cel48A). Furthermore, the catalytic and substrate binding domains of enzymes, belonging to the same GH family were arranged in opposite orientations. Phylogenetic comparisons of the catalytic domain sequences of the T. fusca cellulases to other family GH5, GH6, GH9 and GH48 cellulases of bacterial origin revealed that the enzyme pairs in the same GH family are not closely related to each other, instead they showed significant similarities to various cellulase enzymes from taxonomically distinct organisms. Therefore, the complex and highly efficient cellulase system of T. fusca seems to be evolved as a result of horizontal gene transfers rather than gene duplication events. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Phylogenetic study on Shiraia bambusicola by rDNA sequence analyses
Authors: Cheng Tian‐Fan , Jia Xiao‐Ming , Ma Xiao‐Hang , Lin Hai‐ping , Zhao Yu‐Hua 
Published: September 2004

AbstractIn this study, 18S rDNA and ITS‐5.8S rDNA regions of four Shiraia bambusicola isolates collected from different species of bamboos were amplified by PCR with universal primer pairs NS1/NS8 and ITS5/ITS4, respectively, and sequenced. Phylogenetic analyses were conducted on three selected datasets of rDNA sequences. Maximum parsimony, distance and maximum likelihood criteria were used to infer trees. Morphological characteristics were also observed. The positioning of Shiraia in the order Pleosporales was well supported by bootstrap, which agreed with the placement by Amano (1980) according to their morphology. We did not find significant inter‐hostal differences among these four isolates from different species of bamboos. From the results of analyses and comparison of their rDNA sequences, we conclude that Shiraia should be classified into Pleosporales as Amano (1980) proposed and suggest that it might be positioned in the family Phaeosphaeriaceae. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Peculiar Catalytic Behavior of Poly(vinylidene fluoride) for Cationic Polymerization
Authors: Yamamoto Katsuhiro , Tanaka Hiroyuki , Mouri Masashi , Usami Kaori , Sakaguchi Masato , Shimada Shigetaka , Sasaki Kanako , Akiba Isamu 
Published: September 2004

AbstractSummary: A cationic polymerization of isobutylene, isobutyl vinyl ether, ethyl vinyl ether, vinylcarbazole and α‐methylstyrene was induced by mixing with poly(vinylidene fluoride) (PVDF) powder. The polymerization was an exothermic reaction and gave a high yield. An electron was abstracted from the monomer by PVDF. By the abstraction of the electron, the monomer was converted to a cation radical which induced polymerization. The generation of the cation radicals of the vinyl ethers was confirmed by an ESR spin trapping method, although the cation radicals could be coupled immediately. The resulting polymer was isolated from PVDF (not grafted) and characterized by size exclusion chromatography, IR, UV‐Vis and NMR spectroscopy. The copolymerization of vinyl ethers or vinyl ether/vinylcarbazole was carried out successfully to obtain their random copolymer. PVDF is regarded as a reusable catalyst for cationic polymerizations.Reaction mechanism of the cationic polymerization of iBVE.magnified imageReaction mechanism of the cationic polymerization of iBVE.
Activation of Titanium‐Based Single‐Site Catalysts for Ethylene Polymerization Using Supports of Type MgCl2/AlRn(OEt)3–n
Authors: Severn John R. , Chadwick John C. 
Published: September 2004

AbstractSummary: Easy and effective immobilization and activation of a range of Ti‐based single‐site catalysts for ethylene polymerization has been achieved, without methylaluminoxane or borate activators, using MgCl2/AlRn(OEt)3–n supports obtained by reaction of AlR3 with adducts of magnesium chloride and ethanol. The use of relatively low catalyst loadings leads to efficient uptake by the support and gives high catalyst activity. Catalyst immobilization using these MgCl2‐based supports also leads to stable polymerization kinetics, with negligible decay in catalyst activity during polymerization. Metallocene, half‐metallocene, and non‐metallocene catalysts have been used, particularly high activities being obtained using cyclopentadienyl titanium trichloride and its analogues. The polyethylenes obtained have narrow molecular weight distribution, with $\overline M _{\rm w} /\overline M _{\rm n}$ generally in the range 2–3, indicating retention of single‐site catalyst characteristics after immobilization. Spherical polymer particle morphology was achieved, without reactor fouling.Temperature profile of ethylene polymerization using [(Indenyl)TiCl3] immobilized on a MgCl2/AlEtn(OEt)3–n support (▴: internal temperature; ▪: cooling mantle temperature).magnified imageTemperature profile of ethylene polymerization using [(Indenyl)TiCl3] immobilized on a MgCl2/AlEtn(OEt)3–n support (▴: internal temperature; ▪: cooling mantle temperature).
Highly Fluorinated and Crosslinkable Dendritic Polymer for Photonic Applications
Authors: Ma Hong , Luo Jingdong , Kang Seok Ho , Wong Sharon , Kang Jae Wook , Jen Alex K.‐Y. , Barto Rick , Frank Curtis W. 
Published: September 2004

AbstractSummary: A novel crosslinkable dendritic polymer has been synthesized by the thermal polymerization of peripheral aryl trifluorovinyl ether moieties of a highly fluorinated dendrimer. The resulting perfluorocyclobutane(PFCB)‐containing dendritic polymer exhibited excellent processability, low optical loss (0.36 dB · cm−1 at 1 310 nm with 1% dye doping), high thermal stability, and good solvent resistance for waveguide‐based photonic applications.Structure of the crosslinkable fluorinated dendrimer synthesized.imageStructure of the crosslinkable fluorinated dendrimer synthesized.
Novel Gas Separation Membranes Containing Covalently Bonded Fullerenes
Authors: Sterescu Dana M. , Bolhuis‐Versteeg Lydia , van der Vegt Nico F. A. , Stamatialis Dimitrios F. , Wessling Matthias 
Published: September 2004

AbstractSummary: In this work, we report superior mass transport properties of polymers prepared by the covalent coupling of supermolecular carbon cages (e.g., fullerenes, bucky balls) to a poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO) polymer. Dispersing the bucky balls into the polymer reduces gas permeability, whereas covalent bonding enhances permeability up to 80% in comparison to the pure PPO. Gas pair selectivity, however, is not compromised and stays constant.Schematic representation of the PPO polymer membrane and the PPO‐covalently bonded C60 polymer membrane.imageSchematic representation of the PPO polymer membrane and the PPO‐covalently bonded C60 polymer membrane.
The pallidosubthalamic projection: An anatomical substrate for nonmotor functions of the subthalamic nucleus in primates
Authors: Karachi Carine , Yelnik Jérôme , Tandé Dominique , Tremblay Léon , Hirsch Etienne C. , François Chantal 
Published: September 2004

AbstractThe subthalamic nucleus (STN) is the best target for correcting motor disability in parkinsonian patients with high‐frequency stimulation. However, STN stimulation has also been reported to modify cognitive, emotional, and motivational functions. The aim of this study was to analyze the topographic organization of the STN according to its inputs coming from the sensorimotor, associative, and limbic territories of the external globus pallidus (GPe) in monkeys, with special reference to the limbic projection. Axonal tracers were injected into the different functional territories of the GPe. Injection performed in the limbic GPe resulted in labeling of cell bodies in the dorsal nucleus accumbens and in a dense labeling of axons in the anterior and medioventral portion of the STN. In comparison, injections in the associative and sensorimotor GPe led to labeling in the central and dorsolateral parts of the STN, respectively. Individual pallidosubthalamic axons ramified into numerous varicose branches, which were restricted to a given territory in the STN. These data provide a functional cartography of this structure in primates and suggest that behavioral disorders observed in stimulated parkinsonian patients could result from a dysfunction of the limbic part of the STN. © 2004 Movement Disorder Society
Case–control study of multiple system atrophy
Authors: Vanacore Nicola , Bonifati Vincenzo , Fabbrini Giovanni , Colosimo Carlo , De Michele Giuseppe , Marconi Roberto , Stocchi Fabrizio , Nicholl David , Bonuccelli Ubaldo , De Mari Michele , Vieregge Peter , Meco Giuseppe 
Published: September 2004

AbstractThe epidemiology of multiple system atrophy (MSA) is scarcely known, and risk factors have not been definitely identified. We investigated the effect of family history for neurodegenerative diseases and environmental factors on MSA risk in a multicentric case–control study. A total of 73 MSA patients (42 men, 31 women; age, 64.3 ± 8.1 years; disease duration, 4.8 ± 3.9 years), 146 hospital controls (84 men, 62 women; age, 64.9 ± 8.4 years), and 73 population controls (42 men, 31 women; age, 63.7 ± 8.9 years) matched for sex, age (±3 years), and province of residence were enrolled consecutively at seven neurological centers from 1 January 1994 to 31 July 1998. The following variables were investigated: family history of neurodegenerative diseases, education, smoking habits, hobbies, and occupational history. Occupational history of farming was significantly more frequent among MSA cases than controls (OR adj = 2.52; 95% CI, 1.25 to 5.07, MSA vs. hospital controls; OR adj = 4.53; 95% CI, 1.68 to12.2, MSA cases vs. population controls). A dose–response analysis for years of farming corroborated this association. We recently found that smoking is significantly less frequent among MSA cases than controls (Vanacore et al. [2000] Neurology 54:114–119). Here, we report that the effects of farming and smoking on MSA risk do not interact. Our results suggest that occupational history of farming is a risk factor for MSA. Smoking and farming seem to influence MSA risk independently. Further epidemiological studies might provide clues on the etiopathogenesis of MSA. © 2004 Movement Disorder Society
A general formulation of hypoplasticity
Authors: Lanier J. , Caillerie D. , Chambon R. , Viggiani G. , Bésuelle P. , Desrues J. 
Published: September 2004

AbstractA general formulation of the theory of hypoplasticity is given, under the assumption that Cauchy stress is the only state variable. Such a formulation allows to discuss the relation between the so‐called out‐of‐axis and in‐axis moduli. It is proved that, in general, the out‐of‐axis moduli are independent from the in‐axis moduli, which allows the former to be calibrated making use of experimental shear band data, as it is done in CLoE‐hypoplasticity. The implicit assumptions made in K‐hypoplasticity are detailed for two particular models of this family. Copyright © 2004 John Wiley & Sons, Ltd.
Advanced programming methods and data structures for computational modelling using edge‐based finite volume methods
Authors: Masters I. , Rees I. , Lewis R.W. 
Published: September 2004

AbstractThe generation of a numerical model must consider the separate issues of the governing equations, the numerical representation of those equations, the data structure that describes the model, the choice of programming language and finally the implementation and code management issues. These issues are considered as a whole in this paper and as a consequence, 10 golden rules for numerical modelling are proposed. By way of application, a saturated–unsaturated flow problem is modelled using the Richards equation and an innovative edge‐based finite volume method. The implementation uses a novel data structure. This is shown to have over 91% code re‐use and hence code written in this way is highly flexible and applicable to many different problems. By way of example, a compacted core earth filled dam problem has been solved. Finally, we conclude that this advanced programming method can significantly reduce code development time. Copyright © 2004 John Wiley & Sons, Ltd.