bluuebunny/crossref_metadata_2025_split huggingface dataset:
Serum IgA levels induced by rotavirus natural infection, but not following immunization with the RRV‐TV vaccine (Rotashield™), correlate with protection
Authors: González Rosabel , Franco Manuel , Sarmiento Luis , Romero Milagros , Schael Irene Pérez 
Published: June 2005

AbstractTo directly compare serum rotavirus specific IgA as a marker of protection in children vaccinated with the RRV‐TV (Rotashield™) vaccine and in naturally infected children, we studied pre‐existing rotavirus IgA antibodies by ELISA assays in these groups of children within the first 5 days after the onset of a diarrhea episode, due or not to rotavirus. In immunized children, rotavirus IgA titers were similar between infected and non‐RV infected children. In non‐immunized children, the proportion with rotavirus IgA titers was significantly greater in non‐RV infected children (58%) than in infected children (31%). Additionally, a titer ≥1:800 was associated with 68% protection. Thus, in this study serum rotavirus IgA showed a good correlation with protection in children pre‐exposed to natural infection but not in those immunized with the RRV‐TV vaccine. J. Med. Virol. 76:608–612, 2005. © 2005 Wiley‐Liss, Inc.
The bistable TPID/CHCl3 photoreaction: Numerical simulation and experimental results
Authors: Borderie B. , Lavabre D. , Levy G. , Micheau J. C. , Laplante J. P. 
Published: June 2005

AbstractInvestigation of the photochromic system TPID/CHCl3 (TPID = triphenylimidazolyl dimer) in a CSTR provided the first example of isothermal photochemical bistability. The reaction mechanism was established and the relevant kinetic and spectroscopic parameters were estimated experimentally. In order to predict the quantitative dynamic behavior of the TPID/CHCl3 system these parameters were refined numerically using batch reactor data.The adjusted model simulates very accurately bistability either as a function of residence time τ, or as a function of incident photon flux I0.
An experimental and modeling study of ethanol oxidation kinetics in an atmospheric pressure flow reactor
Authors: Norton T. S. , Dryer F. L. 
Published: June 2005

AbstractExperimental profiles of stable species concentrations and temperature are reported for the flow reactor oxidation of ethanol at atmospheric pressure, initial temperatures near 1100 K and equivalence ratios of 0.61–1.24. Acetaldehyde, ethene, and methane appear in roughly equal concentrations as major intermediate species under these conditions. A detailed chemical mechanism is validated by comparison with the experimental species profiles. The importance of including all three isomeric forms of the C2H5O radical in such a mechanism is demonstrated. The primary source of ethene in ethanol oxidation is verified to be the decomposition of the C2H4OH radical. The agreement between the model and experiment at 1100 K is optimized when the branching ratio of the reactions of C2H5OH with OH and H is defined by (30% C2H4OH + 50% CH3CHOH + 20% CH3CH2O) + XH. As in methanol oxidation, HO2 chemistry is very important, while the H + O2 chain branching reaction plays only a minor role until late in fuel decay, even at temperatures above 1100 K.
Gas‐phase reactions of 1,4‐benzodioxan, 2,3‐dihydrobenzofuran, and 2,3‐benzofuran with OH radicals and O3
Authors: Atkinson Roger , Arey Janet , Tuazon Ernesto C. , Aschmann Sara M. 
Published: June 2005

AbstractThe kinetics of the gas‐phase reactions of 1,4‐benzodioxan, 2,3‐dihydrobenzofuran, and 2,3‐benzofuran with OH radicals and O3 have been studied at 298 ± 2 K and atmospheric pressure of air and the products have also been investigated. 1,4‐Benzodioxan and 2,3‐dihydrobenzofuran were chosen as volatile model compounds for dibenzo‐p‐dioxin and dibenzofuran, respectively. The rate constants, or upper limits thereof, for the O3 reactions were (in cm3 molecule−1 s−1 units): 1,4‐benzodioxan, <1.2 × 10−20; 2,3‐dihydrobenzofuran, <1 × 10−19; and 2,3‐benzofuran, (1.83 ± 0.21) × 10−18. Using a relative rate method, the rate constants for the OH radical reactions (in cm3 molecule−1 s−1 units) were: 1,4‐dibenzodioxan, (2.52 ± 0.38) × 10−11; 2,3‐dihydrobenzofuran, (3.66 ± 0.56) × 10−11; and 2,3‐benzofuran, (3.73 ± 0.74) × 10−11. Salicylaldehyde was observed as a product of the OH radical‐initiated and O3 reactions of 2,3‐benzofuran, with measured formation yields of 0.26 ± 0.05 and 0.13 ± 0.07, respectively.
Role of ionic strength in the kinetics of formation of the monochelate of nickel(II) with heptane‐3,5‐dione
Authors: Moyá María Luisa , Rodriguez Amalia , Sánchez Francisco , Blanco Carlos , Hynes Michael J. 
Published: June 2005

AbstractThe kinetics and mechanism of the reaction of Ni(II) with heptane‐,5‐dione (Hhptd) have been investigated in concentrated sodium perchlorate aqueous solutions at 298 K. The kinetic data in the different media are consistent with a mechanism in which Ni(II) reacts with the enol form of the ligand. The observed positive salt effect on the rate of the reaction of formation of the complex Nihptd+ is rationalized taking into account the increase of the rate of water exchange from the first solvation sphere of the metal ion to the bulk solvent when increasing salt concentration.
FTIR spectroscopic study of the Cl‐ and Br‐atom initiated oxidation of ethene
Authors: Yarwood G. , Peng N. , Niki H. 
Published: June 2005

AbstractThe reaction mechanism of the halogen (Cl and Br)‐atom initiated oxidation of C2H4 was studied using the long path FTIR spectroscopic method in 700 torr of air at 296 ± 2 K. Among the major halogen‐containing products were XCH2CHO, XCH2CH2OH, and XCH2CH2OOH (X = Cl or Br) which were shown to be formed via the self‐reaction of the XCH2CH2OO radicals, i.e., 2XCH2CH2OO → 2XCH2CH2O + O2; (a) 2XCH2CH2OO → XCH2CHO + XCH2CH2OH + O2 and (b) followed by XCH2CH2O + O2 → XCH2CHO + HO2 and XCH2CH2OO + HO2 → XCH2CH2OOH + O2. From the observed yields of XCH2CHO and XCH2CH2OH the branching ratios for reactions (a) and (b) were determined to be ka/kb = 1.35 ± 0.07(2σ) for both X = Cl and Br. In addition, the O2‐dependence of the rate constant for the Br + C2H4 reaction was determined by the relative rate technique as a function of O2 partial pressure from 140 to 700 torr at 700 torr total pressure of N2/O2 diluent. Rate constants for the reactions of Cl‐atoms with Cl‐CH2CHO and Br‐atoms with Br‐CH2CHO were also determined to be [4.3 ± 0.2(2sigma;)] × 10−11 and less than or equal to [1.83 ± 0.11(2σ)] × 10−13 cm3 molecule−1 s−1, respectively.
Kinetic study of n‐heptane oxidation
Authors: Chakir A. , Bellimam M. , Boettner J. C. , Cathonnet M. 
Published: June 2005

AbstractThe oxidation of n‐heptane has been studied in a jet‐stirred flow reactor in the temperature range 950–1200 K at atmospheric pressure for a wide range of fuel‐oxygen equivalence ratios (0.2 to 2.0). A chemical kinetic reaction mechanism developed from previous studies on smaller hydrocarbons and extended to C6 and C7 species was used to reproduce the experimental data. Good agreement between computed and measured concentrations of major chemical species was obtained for the entire range of experimental conditions. Sensitivity analyses were carried out to identify the reactions having the greatest influence on the modeling results. The major reaction paths for n‐heptane consumption and for the formation of the main products have been identified.In addition n‐heptane ignition delays behind a reflected shock wave measured by other investigators were used to validate the present reaction mechanism at higher temperature and pressure.
Influence of anodic oxidation at low potential on the Corrosion resistance of hafnided zirconium in concentrated sulphuric media
Authors: Chatainier G. , Petit J. A. , Dabosi F. 
Published: June 2005

AbstractIn the context of increasing applications of zirconium in the chemical processing industry the influence of anodic oxidation at low potentials on the corrosion resistance of zirconium has been studied. Experiments were performed in concentrated sulphuric acid media, using electrochemical methods. A transition range of potentials between −65 and −50 mV/SCE has been observed. On each side of this transition range hafnided zirconium covered with passive film exhibits different corrosion resistance. Alteration of the passive film, which can be assumed from nuclear microanalysis experiments, has been hypothesized to take account for the modification of the electrochemical behaviour.
Schadensfälle an chirurgischen Implantaten und deren Ursachen
Authors: Zitter H. , Schaschl‐Outschar D. 
Published: June 2005

AbstractSeit dem erstmaligen Einsatz von Chrom‐Nickel‐Molybdän‐Stählen für Implantate in den 30er Jahren, hat die Entwicklung der chemisch beständigen Stähle große Fortschritte gemacht, die in den Werkstoffnormen für Implantate bis heute kaum einen Niederschlag gefunden haben.Eine statistische Auswertung von Schadensfällen läßt in Übereinstimmung mit der Lage der charakteristischen Potentiale erkennen, daß Lochfraß, Spaltkorrosion und die dadurch verursachten Korrosionsdauerbrüche durch höhere Chrom‐ und Molybdängehalte leicht vermieden werden können. Stähle, die diesen Anforderungen gerecht werden, sind in allen Normen enthalten und würden allein vom wirtschaftlichen Standpunkt ihren Einsatz rechtfertigen.
Intergranular corrosion of alloy 800 by the electrochemical potentiokinetic reactivation method
Authors: Borello A. , La Barbera A. , Mignone A. , Vittori M. 
Published: June 2005

AbstractThe “Electrochemical Potentiokinetic Reactivation” method has been employed to quantify the degree of intergranular corrosion of Alloy 800, with different Ti + Al content, aged in the range 500–650°C for times up to 5000 hours. The results were compared with the classical Rollason's curves obtained by means of the Strauss' test and a satisfactory agreement was found.An explanation of the slight differences between both methods has been proposed on the basis of the passivity film morphology.
Veränderungen Feuerfester Pulver beim Plasmaspritzen
Authors: Pilous V. 
Published: June 2005

AbstractEs werden Ergebnisse des Durchgangs von Pulvern auf der Basis von NiCrBSi, A12O3‐TiO2 und Mo durch den Plasmabogen bei Temperaturen von 16000 K und 20000 K angeführt. Weiter wird der Gefügeaufbau von Ni3B und Al2O3 beim Durchgang verfolgt. Plasmabogentemperaturen zum Spritzen von Pulvern der erwähnten Basen werden empfohlen.
The effect of thermo‐mechanical treatment on The pitting corrosion of reinforcing carbon steel bars
Authors: Groza Joanna R. , Eslamloo‐Grami M. , Bandy R. 
Published: June 2005

AbstractSteel reinforcing rods with varying amounts of cold work and carbon concentrations (0.06 to 0.45% C) exposed in soil embankments has shown various degrees of pitting corrosion. To understand this pitting process, laboratory investigations on residual stresses, microstructures and potentiodynamic cyclic polarization were undertaken. Analysis of residual stresses in the steels indicated low value of compressive stresses in hot rolled steels and high value of tensile stresses in the cold worked counterparts. Hot rolled steels displayed a slightly better pitting corrosion resistance than cold worked samples which is consistent with the above internal stress pattern. No definite correlation was obtained between the percentage of carbon in the steels and pitting susceptibility. An attempt has been made to define the role of the complex steel‐soil system for pitting corrosion behavior.
Beeinträchtigung der Lochkorrosionsbeständigkeit von CrNi‐Stählen durch dünne Oxidschichten
Authors: Diab A. S. M. , Schwenk W. 
Published: June 2005

AbstractProben aus Werkstoff‐Nr. 1.4301 und 1.4571 wurden mittels potentiostatischer Halteversuche auf chlorid‐induzierte Lochkorrosion untersucht. Parameter waren der Oberflächenzustand mit dünnen Oxidschichten (Anlauffarben bis blau), Zusatz von Inhibitoren (Sulfate, Nitrate), Temperatur. Es wurden zwei Lochfraßpotentiale ermittelt, die über stabile Passivität, latente und stabile Lochkorrosion informieren.Die Ergebnisse zeigen, daß der Einfluß der Temperatur und des Mo‐Gehaltes nicht sehr groß ist. Einen starken Einfluß können die Inhibitorzusätze haben. Gebeizte Proben sind wesentlich beständiger als solche mit strohgelber Anlauffarbe, während die Lochfraßbeständigkeit zwischen Proben mit gelber und blauer Anlauffarbe nicht sehr unterschiedlich ist. Im Trend werden aber die Lochfraßpotentialbereiche mit zunehmender Oxidschichtdicke (gelb bis blau) erweitert.
Saccharide und deren Derivate als Korrosionsinhibitoren für Aluminiumpigmente in wäßrigen Medien
Authors: Müller Bodo , Kurfeß Martin 
Published: June 2005

AbstractAluminiumpigmente (Al‐Gehalt > 99,5%) unterliegen in wäßrigen, leicht alkalischen Metalliclacken der Korrosion, deren zeitlicher Verlauf sich durch volumetrische Bestimmung des entstehenden Wasserstoffs leicht verfolgen läßt. Als einfache Modellsysteme zur Prüfung von Mono‐, Di‐ und Polysacchariden, sowie Derivaten davon, als Korrosionsinhibitoren wurden zwei Wasser/Butylglykol‐Gemische gewählt, deren pH‐Wert zur Beschleunigung der Korrosionsreaktion auf 10 eingestellt wurde. Darüber hinaus wurde versucht, durch Vergleich mit geeigneten Modellsubstanzen Struktur‐Wirkungs‐Beziehungen aufzustellen. Zwei Substanzklassen erwiesen sich als wirksam:
Reduzierend wirkende Mono‐ und Disaccharide inhibieren die Korrosion wahrscheinlich über das im Gleichgewicht vorliegende Endiolstukturelement.
Die untersuchten Hydroxycarbonsäuren bilden vermutlich Chelatkomplexe, die dann korrosionsinhibierend wirken.
Als wirksamster aller hier untersuchten Inhibitoren zeigte sich das stark reduzierend wirkende Endiol Ascorbinsäure.
Einfluß von Passivierungs‐ und Kohlenstoffschichten auf austenitischen CrNiMo‐Stählen auf die Beständigkeit gegen Lochfraß und Spannungsrißkorrosion
Authors: Marciniak J. , Boba J. , Paszenda Z. , Mitura S. 
Published: June 2005

AbstractDer Einfluß von Passivierungsschichten und Schichtkombinationen (bestehend aus einer Passivierungs‐ und einer Kohlenstoffschicht) auf die Beständigkeit von austenitischen CrNiMo‐Stählen gegen Lochfraß und Spannungsrißkorrosion wurde in physiologischer Tyrode‐Lösung im pH‐Bereich 6,9 bis 7,4 bei 37 ± 1°C untersucht. Die Passivierungsschicht wurde ‐ nach elektrolytischem Polieren in H3PO4+ H2SO4+ C6H5NHCOCH3+ Oxalsäure + Korrosionsinhibitor CS ‐ durch Behandeln mit 40% iger Salpetersäure, die Kohlenstoffschicht durch CVD erzeugt. Die Verunreinigung des Stahls durch nichtmetallische Einschlüsse und der Phasenbestand wurden untersucht und die chemische Zusammensetzung der Passivierungsschicht durch quantitative Analyse ermittelt. Die Widerstandsfähigkeit des Stahls ‐ mit und ohne Passivierungsschicht ‐ gegen Lochfraß wurde potentiodynamisch in Chloridlösung nach Tyrode bei 37 ± 1°C untersucht. Die Beständigkeit gegen Spannungsrißkorrosion wurde in Tyrode‐Lösung bei 37 ± 1°C, in neutralem Glycerin sowie 44% iger MgCl2‐Lösung bei 154°C ± 1°C untersucht und unter Verwendung von Kσund Kτbeurteilt. Die Korrosionsschäden wurden licht‐ und rasterelektronenmikroskopisch untersucht.Die Untersuchungen haben gezeigt, daß die verwendeten Oberflächenschichten die Beständigkeit der Stähle gegen Lochfraß und Spannungsrißkorrosion in den verwendeten Medien wirksam verbessern und damit die Verwendung dieser Materialien für chirurgische Implantate ermöglichen.
Propene‐Ethene Copolymers Synthesised with Cs‐Symmetric Metallocenes and Different Cocatalysts
Authors: Seraidaris Tanja , Kaminsky Walter , Seppälä Jukka V. , Löfgren Barbro 
Published: June 2005

AbstractSummary: Propene‐ethene copolymers with low to moderate amounts of ethene were synthesised with two Cs‐symmetric metallocene complexes, [(p‐CH3OPh)2C(2,7‐di‐tBuFlu)(Cp)]ZrCl2 (I) and [(p‐CH3OPh)2C(2,7‐di‐tBuFlu)(Cp)]HfCl2 (Ia). Methylalumoxane (MAO), N,N‐dimethylanilinium tetra(pentafluorophenyl)borate {[Me2HNPh][B(C6F5)4]}, trityl tetra(pentafluorophenyl)borate {[Ph3C][B(C6F5)4]} and tris(pentafluorophenyl)borane [B(C6F5)3] were used as cocatalysts in the polymerisations. The differences in polymerisation activity, ethene incorporation rate and molecular weight as well as the microstructure and the thermal behaviour of the homo‐ and copolymers were studied.The different cocatalysts have a strong influence on the polymerisation activity and the syndiotacticity of the polymers, but only a minor influence on the ethene incorporation rate and the molecular weight. At 30 °C, the incorporation rate of ethene is ca. 25 times faster for complex I and ca. 16 times faster for complex Ia than the incorporation rate of propene. The thermal behaviour of the homo‐ and copolymers is dependent of the polymerisation temperature and the cocatalyst. I/MAO produces homo‐ and copolymers at 30 °C with more regular microstructure than I/[Me2HNPh][B(C6F5)4], I/[Ph3C][B(C6F5)4] and I/B(C6F5)3 leading to homo‐ and copolymers with higher melting and crystallisation temperatures. On the contrary, at 0 °C I/[Me2HNPh][B(C6F5)4] and I/[Ph3C][B(C6F5)4] produce copolymers with higher propene sequence syndiotacticity and higher melting and crystallisation temperatures than I/MAO. The influence of the cocatalyst on the catalyst coordination environment is temperature‐dependent and thereby the structure of the forming homo‐ or copolymers varies.Effect of different cocatalysts and the amount of ethene in the feed on the polymerisation activity of complex I.magnified imageEffect of different cocatalysts and the amount of ethene in the feed on the polymerisation activity of complex I.
Polyester Dendrimers Carrying NLO Chromophores: Synthesis and Optical Characterization
Authors: Do Jung Yun , Ju Jung Jin 
Published: June 2005

AbstractSummary: Four dendritic polyesters containing non‐linear optical chromophores on the periphery were synthesized and their material properties were compared for electro‐optic device applications. Thermal and optical parameters of the dendrimer materials were measured along with structural analysis. A high chromophore concentration in the dendritic polyesters produced enhancement of the optical non‐linearity. The second generation dendrimer (G1‐DAIDC) exhibited an electro‐optic coefficient of 43.4 pm · V−1 at 1.55 µm optical communication wavelength. Aromatic ester backbones elevate the glass transition temperature of the chromophore alignment, representing good thermal stability of the optical films.
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New Silicon‐Containing Polyquinolines: Synthesis, Characterization, and Electroluminescence
Authors: Tonzola Christopher J. , Alam Maksudul M. , Jenekhe Samson A. 
Published: June 2005

AbstractSummary: This study reports the synthesis, characterization, and electroluminescent device application of three new silicon‐containing polyquinolines: poly(2,2′‐(bis(p‐phenyl)diphenylsilane)‐6,6′‐bis(4‐phenyl quinoline)), poly(2,2′‐(bis(p‐phenyl)octylmethylsilane)‐6,6′‐bis(4‐phenyl quinoline)), and poly(2,2′‐(bis(p‐phenyl)diphenylsilane)‐6,6′‐bis(4‐hexylquinoline)). The polymers with alkyl side chains were soluble in organic solvents. The new polymers showed robust thermal properties with glass transitions of 161–339 °C. Cyclic voltammetry of the polymers revealed quasi‐reversible reductions with onsets of −1.55 to −1.71 V (vs SCE) and corresponding electron affinities of 2.69–2.85 eV. Organic light‐emitting devices using new polyquinolines as emissive materials showed blue (CIE coordinates = 0.21, 0.20) or blue‐green (0.23, 0.36) electroluminescence with a moderate brightness (≈140 cd · m−2) and efficiency (0.04%). The results demonstrate that silicon‐containing polyquinolines are promising n‐type wide band‐gap semiconductors for organic electronics.Structures of new Si‐containing polyquinolines.magnified imageStructures of new Si‐containing polyquinolines.
Site Specific Proton and Deuteron NMR Relaxation Dispersion in Selectively Deuterated Polyisoprene Melts
Authors: Kariyo Sobiroh , Stapf Siegfried , Blümich Bernhard 
Published: June 2005

AbstractSummary: The frequency dependence of proton and deuteron NMR relaxation times was determined in selectively deuterated and undeuterated polyisoprene melts and compared to polybutadiene melts. Master curves were generated by the Williams‐Landel‐Ferry (WLF) formalism which resulted in very similar dispersions for all samples with a high and a low frequency branch following characteristic power laws. The results show a consistently weaker frequency dependence than any reported so far for other polymer melts. The reason for this finding is identified in the distribution of intramolecular motion modes, while intermolecular contributions are ruled out.Master curves for 1H relaxation dispersions obtained from measurements between 223 K and 348 K shifted relative to a reference temperature of 296 K.magnified imageMaster curves for 1H relaxation dispersions obtained from measurements between 223 K and 348 K shifted relative to a reference temperature of 296 K.
Restricted Molecular Dynamics of Polymer Chains by Means of NMR Field Cycling Relaxometry
Authors: Kariyo Sobiroh , Stapf Siegfried 
Published: June 2005

AbstractSummary: The molecular dynamics of polymer melts with molecular weights above their critical values have been described by a power law dependence of the spin‐lattice relaxation time on the Larmor frequency. Three different regimes of power laws describing the relaxation dispersion of polymers for the chain mode dynamics are distinguishable and have been observed experimentally for several types of polymers. In this study, the influence of chemical and physical constraints on the relaxation dispersion of polymers was investigated. This included the introduction of chemical cross‐links and filler particles to produce elastomers, for which further constraints were imposed by mechanical deformation. As an alternative means of affecting molecular mobility, investigations were also carried out for poly(styrene‐block‐butadiene) diblock and poly(styrene‐block‐butadiene‐block‐styrene) triblock copolymers. Reducing the molecular degree of freedom of the chain, i.e., by introducing cross‐links between different segments, was shown to affect the time scale of motion but left the spectrum of the reorientational dynamics virtually unchanged. Only a small effect was found on the addition of filler particles into the elastomer network. On the other hand, applying macroscopic deformation to natural rubber and butadiene rubber samples is shown to alter also the spectrum of reorientations. Generating chemical fixations to immobile microdomains by copolymerizing a soft butadiene phase with a hard polystyrene phase to produce a biphasic lamellar structure is demonstrated to have a comparable effect. The change in slow molecular motion in the kHz to MHz range is discussed using the corresponding frequency dependence of the NMR spin‐lattice relaxation time, and a common description combining measurements at different temperatures is presented.Master curves generated from relaxation dispersions at different temperatures for a BR1/1 sample filled with 30 phr of carbon black under deformation with λ ≈ 3.5 (compared to an unstretched sample).magnified imageMaster curves generated from relaxation dispersions at different temperatures for a BR1/1 sample filled with 30 phr of carbon black under deformation with λ ≈ 3.5 (compared to an unstretched sample).