bluuebunny/crossref_metadata_2025_split huggingface dataset:
Genetic Identification of a Putative Vinyl Chloride Reductase in
Dehalococcoides
sp. Strain BAV1
Authors: Krajmalnik-Brown Rosa , Hölscher Tina , Thomson Ivy N. , Saunders F. Michael , Ritalahti Kirsti M. , Löffler Frank E. 
Published: October 2004

ABSTRACT

Dehalococcoides
sp. strain BAV1 couples growth with the reductive dechlorination of vinyl chloride (VC) to ethene. Degenerate primers targeting conserved regions in reductive dehalogenase (RDase) genes were designed and used to PCR amplify putative RDase genes from strain BAV1. Seven unique RDase gene fragments were identified. Transcription analysis of VC-grown BAV1 cultures suggested that
bvcA
was involved in VC reductive dechlorination, and the complete sequence of
bvcA
was obtained.
bvcA
was absent in
Dehalococcoides
isolates that failed to respire VC, yet was detected in four of eight VC-respiring mixed cultures.
Structural Change and Cobalt Fixation in the Hydrothermally Synthesized Zeolite Phases from a Si–Al–Co Hydrous Oxide
Authors: Nagase Takako , Chatterjee Abhijit , Tanaka Alfred P , Tanco Margot L , Tazaki Kazue 
Published: October 2004

Abstract
A series of Co-zeolite samples were synthesized at 170–200 °C, controlling the reaction between a Si–Al–Co hydrous oxide and NaOH solution. With increase of the reaction time, and NaOH concentration, synthesized phase changed in the sequence of MOR, PHI, and ANA with Na. The results of chemical analysis and FT-IR spectra of each phases showed that NaOH concentration in the initial slurry and the architecture of zeolite affected Co fixation in the zeolite structure.
Practical Synthesis of Optically Active Fluorine-substituted α-Phenylethylamines by Retardation of Hydrogenolytic Cleavage at Benzylic Position
Authors: Kanai Masatomi , Yasumoto Manabu , Kuriyama Yokusu , Inomiya Kenjin , Katsuhara Yutaka , Higashiyama Kimio , Ishii Akihiro 
Published: October 2004

Abstract
High regioselectivity in hydrogenolysis of bis(α-methylbenzyl)amines having a fluorine atom on aromatic ring results from retardation of hydrogenolytic cleavage at benzylic position of fluorine-substituted aromatic ring.
Bi(OTf)3-[Bmim]PF6: A novel and Recyclable Catalytic System for the Diasteroselective Synthesis of Cis-fused Pyrano and Furanobenzopyrans
Authors: Yadav J S , Reddy B V S , Reddy P Narayana 
Published: October 2004

Abstract
The Stereoselective one-pot synthesis of cis-fused pyrano and furanobenzopyrans has been developed from o-hydroxybenzaldehydes, aromatic amines, and cyclic enol ethers in the presence of Bi(OTf)3 in air- and moisture-stable ionic liquid, [bmim]PF6 under mild conditions. The recovered ionic liquid containing Bi(OTf)3 can be reused three to five subsequent runs with only a gradual decrease in activity. The recovery of catalyst is facilitated by its hydrophobic nature of [bmim]PF6.
Evidence for Two Competing Mechanisms in Regeneration of 2-(2,4-Dinitrobenzyl)pyridine from its Enamine Tautomer
Authors: Kira Nobuhiro , Takahashi Toru , Ohga Yasushi , Asano Tsutomu 
Published: October 2004

Abstract
Kinetic effects of pressure on the title reaction were studied. The reaction was insensitive to a change in pressure at 0.1 MPa, however, it was accelerated by an increase in pressure at P &gt; 100 MPa, showing the existence of two reaction routes with and without solvent participation. Viscosity-induced retardations observed in highly viscous media supported intervention of solvent molecules at high pressures.
UV–vis Absorption Spectra of Powdered Materials: Direct Measurements by Optical Waveguide Spectroscopy
Authors: Ogawa Keiichiro , Harada Jun , Fujiwara Toshikatsu , Takahashi Hiromi 
Published: October 2004

Abstract
UV–vis absorption spectra of powders of naphthalene and salicylideneaniline were obtained using optical waveguide spectroscopy. It is demonstrated that the optical waveguide spectroscopy is an excellent method for the measurement of UV–vis absorption spectra of powdered materials as they are, without any treatment.
Paraneoplastic antibodies coexist and predict cancer, not neurological syndrome
Authors: Pittock Sean J. , Kryzer Thomas J. , Lennon Vanda A. 
Published: October 2004

AbstractWe investigated coexisting autoantibodies in sera of 553 patients with a neurological presentation and one or more paraneoplastic neuronal nuclear or cytoplasmic autoantibodies: antineuronal nuclear autoantibody type 1 (ANNA‐1), ANNA‐2, ANNA‐3; Purkinje cell cytoplasmic autoantibody type 1 (PCA‐1), PCA‐2; and CRMP‐5–immunoglobulin G or amphiphysin–immunoglobulin G. Except for PCA‐1, which occurred alone, 31% of sera had more than one of these autoantibodies. In addition, 25% of sera had neuronal calcium channel (P/Q‐type or N‐type), potassium channel, ganglionic acetylcholine receptor, muscle acetylcholine receptor, or striational antibodies. The autoantibody profiles observed in patients with paraneoplastic disorders imply the targeting of multiple onconeural antigens and predict the patient's neoplasm, but not a specific neurological syndrome. Ann Neurol 2004
Modification of lignin–polyethylene blends with high lignin content using ethylene–vinylacetate copolymer as modifier
Authors: Alexy Pavol , Košíková Božena , Crkonová Gabriela , Gregorová Adriána , Martiš Pavol 
Published: October 2004

AbstractBlending of polyethylene with lignin in concentrations > 20 wt % yielded blends with relatively low mechanical properties. A new method, based on modification of polyethylene with ethylene–vinylacetate (EVA) copolymer, was developed for the preparation of polyethylene blends containing about 30 wt % lignin with acceptable strength properties. The addition of 10 wt % EVA caused an increase of tensile strength about twice and elongation at break about 13 times compared to those of the corresponding nonmodified samples. The optimization of lignin–polyethylene–EVA blend composition was based on a regression equation, which was obtained as output from an experimental design. The prepared composite material with 33.6 wt % lignin showed acceptable processing and mechanical properties. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1855–1860, 2004
Particle features of a poly(methyl methacrylate) resin prepared by a new emulsion polymerization process
Authors: Bao Yong‐Zhong , Huang Zhi‐Ming , Weng Zhi‐Xue 
Published: October 2004

AbstractA new emulsion polymerization process, in which water acted as the dispersed phase and a mixture of methyl methacrylate (MMA) and cyclohexane acted as the continuous phase, was applied to the preparation of a poly(methyl methacrylate) (PMMA) resin. The primary (latex) particles were formed in the early stage of polymerization and coagulated as the polymerization conversion increased. Scanning electron micrographs showed that the final PMMA particles were porous and composed of loosely aggregated primary particles. The porosity characterized by cold di(2‐ethylhexyl) phthalate absorption increased as the water/oil and cyclohexane/MMA mass ratios increased. The PMMA primary particles were smaller than the primary particles in the PMMA resin prepared by suspension polymerization in the presence of cyclohexane. Because of the phase composition of the reaction system, the solubility of PMMA in a mixture of cyclohexane and MMA, and the particle morphology of PMMA, a particle formation mechanism, including the formation, growth, and coagulation of primary particles in dispersed water droplets, was proposed. The primary particles formed mainly through a homogeneous nucleation mechanism and increased in size as MMA diffused from the oil phase to the water phase to the primary particles. The coagulation of the primary particles occurred because of the lower colloidal stability and the space limitations of the primary particles. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1905–1911, 2004
Independent control of lower critical solution temperature and swelling behavior with pH for poly(N‐isopropylacrylamide‐co‐maleic acid)
Authors: Weiss‐Malik Rachael A. , Solis Francisco J. , Vernon Brent L. 
Published: October 2004

AbstractPolymer solutions that gel in response to changes in temperature and pH are of interest for various forms of drug delivery, and it is desirable to increase swelling for diffusion‐controlled release without bringing the lower critical solution temperature (LCST) above 37°C. N‐isopropylacrylamide (NIP) was polymerized with maleic acid (MAc), a diprotic acid, and acrylic acid (AAc), a monoprotic acid, to compare swelling and temperature response with changes in pH. For samples with equal acid contents and almost identical LCST responses to pH, poly(N‐isopropylacrylamide‐co‐maleic acid) (pNIP MAc) demonstrated greater swelling than poly(N‐isopropylacrylamide‐co‐acrylic acid) (pNIP AAc). The LCST increase for MAc occurred at a pH corresponding to the deprotonation of almost all of the first acid groups. Further increases in pH led to the deprotonation of the second COOH and only served to increase the charge concentration at a given location. These results provide strong support for the theory that LCST results largely from uninterrupted chain lengths of NIP and that swelling results from the actual charge density of acid groups along the chain. Because the use of a diprotic acid copolymer allows swelling to be decoupled from LCST, pNIP MAc may be an appropriate candidate for pH‐sensitive drug‐delivery applications. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2110–2116, 2004
Surface and thermal characteristics of rubber‐modified aromatic polyamide
Authors: Park Young‐Wook , Lee Dong‐Sung 
Published: October 2004

AbstractPolyamide/epoxysilane (coupling agent) composites were reacted with poly(dimethylsiloxane) (PDMS), a condensation product of diethoxydimethylsilane (DEDMS), by a sol–gel process. Polyamide–PDMS nanocomposites were obtained. The existence of the condensation product of DEDMS and the reaction between the epoxy group and the polyamide were confirmed with Fourier transform infrared, attenuated total reflection, and wide‐scanning X‐ray photoelectron spectroscopy. Atomic force microscopy and contact‐angle measurements showed that the surface properties of polyamide were greatly improved by the addition of PDMS. The pyrolysis temperature of polyamide with PDMS was approximately 400°C, and the pyrolysis temperature was similar to that of pure polyamide. Also, the char contents increased with the addition of PDMS. The glass‐transition temperature of polyamide with or without PDMS was approximately 140°C according to differential scanning calorimetry. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1947–1955, 2004
Preparation of silica‐filled poly(2‐hydroxymethyl methacrylate) nanocomposites cured by photoirradiation during the sol–gel process
Authors: Lin Dar‐Jong , Chen Ching‐Chung , Su Yi‐Che , Huang Shu‐Hui , Cheng Liao‐Ping 
Published: October 2004

AbstractThe sol–gel process was used to prepare a photosensitive inorganic–organic composite, silica/poly(2‐hydroxymethyl methacrylate). Its nanoscale morphology was observed with field emission scanning electron microscopy at high magnifications (e.g., 160,000×). The size of the particles in the nanocomposite synthesized under various preparation conditions fell in the range of 20–50 nm. The effects of the pH, reactant composition, and solvent content in the reaction mixture on the thermal and mechanical properties of the nanocomposite were studied with thermogravimetric analysis, dynamic mechanical analysis, and thermomechanical analysis. The thermal stability of the synthesized nanocomposite could generally be improved by an increase in the molar ratio of the inorganic component, a reduction in the reaction pH, or an increase in the solvent content. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1927–1935, 2004
Influence of temperature changes on crystallization of an ethylene–propylene random copolymer
Authors: Raimo Maria 
Published: October 2004

AbstractUnconventional procedures were used to crystallize an ethylene/propylene copolymer (E/P), with the aim of investigating the effect of temperature changes on crystallization kinetics and spherulitic morphology. The solidification process of specimens crystallizing under isothermal conditions was cyclically stopped for a while, by increasing the temperature, and afterward reestablished by cooling at the original temperature. The resulting morphology characterized by rings within spherulites was compared to that obtained by continuous isothermal crystallization. The different temperature dependencies of the thermal expansion coefficients of liquid and solid phases account for the presence of rings within spherulites grown in a temperature field. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2008–2013, 2004
Study of plasma polymerization of dichloromethane on cotton and polyester fabrics
Authors: Jahagirdar C. J. , Tiwari L. B. 
Published: October 2004

AbstractDichloromethane (DCM) was polymerized on cotton and polyester fabrics in nonequilibrium low‐temperature plasma for different durations and the effects obtained were discussed. The modified cotton and polyester fabrics were dyed with Reactive Red HE 8BI and C.I. Disperse Red 364 dyes, respectively. The relative color strength of polymerized dyed fabrics was measured and compared with that of untreated dyed fabrics. The color parameters of polymerized fabrics were evaluated by the CIE system of color measurement, with standard illuminant D65 and 10° standard observer, by a Dataflash 100 color measurement spectrophotometer equipped with Colortools QC 1.3 color quality control software. The chemical structures of untreated and polymerized fabrics were studied by attenuated total reflectance–infrared spectroscopy. The presence of free radicals, attributed to the polymerization, was measured by electron spin resonance spectroscopy. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2014–2021, 2004
Alloying of poly(vinyl chloride) to reduce plasticizer migration
Authors: Thomas N. L. 
Published: October 2004

AbstractConcern over the migration of low molecular weight plasticizer from flexible poly(vinyl chloride) (PVC) used in toys and medical products has spearheaded the commercialization of a number of plasticizing polymers. In this study the plasticizing behavior of an ethylene/vinyl acetate/carbon monoxide terpolymer (Elvaloy® from DuPont) was investigated. Blends of PVC, Elvaloy 742, and dioctyl phthalate (DOP) were processed on a twin‐roll mill and compression molded into plaques. These materials were characterized in terms of their hardness, glass‐transition temperature (Tg), clarity, mechanical properties, and plasticizer migration behavior. The ratios of PVC/DOP/Elvaloy investigated were determined by experimental design. Using this approach it was possible to model the results and produce contour plots to map out the properties of a wide range of formulations. It was confirmed that Elvaloy 742 is compatible with PVC and has a plasticizing effect: this was demonstrated both in terms of a reduction in Shore A hardness and a reduction in Tg. Plasticizer migration was reduced in proportion to the amount of liquid plasticizer replaced. Plasticizing with Elvaloy gave an improvement in tear strength. However, at constant hardness there was no improvement in tensile strength from replacing DOP with Elvaloy. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2022–2031, 2004
Metallization of crosslinked epoxy resins derived from diglycidyl ethers of poly(ethylene glycol) and bisphenol a by reduction of polymer‐incorporated cobalt ion
Authors: Shibata Mitsuhiro , Kuribayashi Masamichi , Uda Takayasu 
Published: October 2004

AbstractThe surface of the blend films of poly(ethylene glycol) diglycidyl ether (PEG‐E) and bisphenol A diglycidyl ether (BPA‐E) cured with 5‐(2,5‐dioxotetrahydrofuryl)‐3‐methyl‐3‐cyclohexene‐1,2‐dicarboxylic acid anhydride at 200°C for 5 h was metallized by the reduction of polymer‐incorporated cobalt acetate with aqueous sodium borohydride at 20–50°C. Although the cured films of PEG‐E/BPA‐E, weight ratio 100/0–80/20, were successfully metallized, the blend ratio 60/40 did not afford a metallized film by this reduction method. The glass transition temperature (Tg) of the cured resin measured by dynamic viscoelastic analysis rose with an increase of BPA‐E content. The difficulty of surface metallization in the case of blend ratio 60/40 is related to the hindrance of migration of cobalt ion due to the restriction of molecular chain motion. Electron probe microanalysis and X‐ray photoelectron spectroscopy measurement revealed that the cobalt ion that was homogeneously distributed in the inner part of the film before reduction migrated to both sides of the film and then was reduced to pure metal by the reduction treatment. The X‐ray diffraction analysis of the reduced films revealed that the generated cobalt was almost amorphous. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 2164–2169, 2004
Neural tube defect rates before and after food fortification with folic acid
Authors: Mills James L. , Signore Caroline 
Published: October 2004

AbstractBACKGROUNDSince 1998, enriched cereal grains sold in the United States have been fortified with folic acid, to reduce the incidence of neural tube defects (NTDs). The Centers for Disease Control and Prevention (CDC) recently reported that NTD rates have decreased 26% since fortification, but that additional effort is needed to achieve the national goal of a 50% reduction. However, accurate determination of NTD rates requires counting antenatally detected cases; the CDC study noted that the number of prenatally diagnosed cases was likely underestimated.METHODS AND RESULTSWe examined studies from the United States and Canada that compared rates of NTDs before and after very similar fortification programs were instituted in each country. U.S. studies had incomplete ascertainment of prenatally diagnosed NTD cases, and as a result, underreported the number of NTDs prevented. Canadian studies, in which ascertainment was more complete, showed decreases in NTD rates up to 54%.CONCLUSIONSThere is a strong correlation between the completeness of ascertainment and the percentage decrease in NTD rates. Studies that identify cases best show that folic acid fortification is preventing around 50% of NTDs. The percentage of NTDs that are folate‐preventable in the United States is uncertain, but is probably 50–60%. Thus, we may be quite close to achieving the optimum level of protection at current fortification levels. Birth Defects Research (Part A), 2004. Published 2004 Wiley‐Liss, Inc.
Structural analysis of amyloid β peptide fragment (25–35) in different microenvironments
Authors: Shanmugam Ganesh , Jayakumar Rajadas 
Published: October 2004

AbstractAmyloid β (Aβ) peptides are one of the classes of amphiphilic molecules that on dissolution in aqueous solvents undergo interesting conformational transitions. These conformational changes are known to be associated with their neuronal toxicity. The mechanism of structural transition involved in the monomeric Aβ to toxic assemblage is yet to be understood at the molecular level. Early results indicate that oriented molecular crowding has a profound effect on their assemblage formation. In this work, we have studied how different microenvironments affect the conformational transitions of one of the active amyloid β‐peptide fragments (Aβ25–35). Spectroscopic techniques such as CD and Fourier transform infrared spectroscopy were used. It was observed that a stored peptide concentrates on dissolution in methanol adopts a minor α‐helical conformation along with unordered structures. On changing the methanol concentration in the solvated film form, the conformation switches to the antiparallel β‐sheet structure on the hydrophilic surface, whereas the peptide shows transition from a mixture of helix and unordered structure into predominantly a β‐sheet with minor contribution of helix structure on the hydrophobic surface. Our present investigations indicate that the conformations induced by the different surfaces dictate the gross conformational preference of the peptide concentrate. © 2004 Wiley Periodicals, Inc. Biopolymers (Pept Sci), 2004
Stacking and hydrogen bonding: DNA cooperativity at melting
Authors: Morozov Vladimir F. , Badasyan Artem V. , Grigoryan Arsen V. , Sahakyan Mihran A. , Mamasakhlisov Yevgeni Sh 
Published: October 2004

AbstractBy taking into account base–base stacking interactions we improve the Generalized Model of Polypeptide Chain (GMPC). Based on a one‐dimensional Potts‐like model with many‐particle interactions, the GMPC describes the helix–coil transition in both polypeptides and polynucleotides. In the framework of the GMPC we show that correctly introduced nearest‐neighbor stacking interactions against the background of hydrogen bonding lead to increased stability (melting temperature) and, unexpectedly, to decreased cooperativity (maximal correlation length). The increase in stability is explained as due to an additional stabilizing interaction (stacking) and the surprising decrease in cooperativity is seen as a result of mixing of contributions of hydrogen bonding and stacking. © 2004 Wiley Periodicals, Inc. Biopolymers, 2004
Protein conformational transitions coupled to binding in molecular recognition of unstructured proteins: Hierarchy of structural loss from all‐atom Monte Carlo simulations of p27Kip1 unfolding–unbinding and structural determinants of the binding mechanism
Authors: Verkhivker Gennady M. 
Published: October 2004

AbstractConformational transitions coupled to binding are studied for the p27Kip1 protein which undergoes a functional disorder–to–order folding transition during tertiary complex formation with the phosphorylated cyclin A–cyclin‐dependent kinase 2 (Cdk2) binary complex. Temperature–induced Monte Carlo simulations of p27Kip1 unfolding–unbinding carried out from the crystal structure of the tertiary complex have revealed a systematic trend in the hierarchy of structural loss for p27Kip1 and a considerable difference in mobility of p27Kip1 secondary structure elements. The most persistent interactions of p27Kip1 at the intermolecular interface during unfolding–unbinding simulations are formed by β‐hairpin and β–strand that on average maintain their structural integrity considerably longer than other p27Kip1 elements. We have found that the ensemble of unfolded p27Kip1 conformations is characterized by transitions between mostly unbound, collapsed conformations and entropically favorable p27Kip1 conformations, which are weakly bound to the cyclin A side of the binary complex. The results of this study are consistent with the experimental evidence pointing to this region of the intermolecular interface as a potential initiation docking site during binding reaction and may reconcile conflicting experimental hypotheses on the recognition of substrate recruitment motifs. © 2004 Wiley Periodicals, Inc. Biopolymers, 2004
Ladungsdichtewellen: Elektrische Leitfähigkeit
Authors: Tremel Wolfgang , Finckh E. Wolfgang 
Published: October 2004

AbstractDie physikalischen Eigenschaften von Verbindungen werden im wesentlichen durch deren Aufbau bestimmt. Die Eigenschaften der Elemente sind nur insoweit wichtig, als sie den strukturellen Aufbau und damit die Bildung einer bestimmten Verbindung überhaupt erst ermöglichen. Hier, in der Untersuchung und systematischen Veränderung der Substanzeigenschaften liegt die eigentliche Schnittstelle von Chemie und Physik – der Chemiker muss allerdings neben der Synthese, die sein eigentliches Handwerk ist, noch die Grundlagen der Physik so weit beherrschen, dass er die relevanten Fragestellungen erfasst. Umgekehrt muss der Physiker eine gewisse Stoffkenntnis besitzen, um ein Gespür dafür bekommen, welche Verbindung oder Verbindungsgruppe die von ihm gewünschten Eigenschaften besitzen könnte.