bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimization of a new resin, Amberlyst 36, as a solid‐phase extractor and determination of copper(II) in drinking water and tea samples by flame atomic absorption spectrometry
Authors: Kendüzler Erdal , Türker Ali Rehber 
Published: November 2005

AbstractA new simple and reliable method has been developed to separate and preconcentrate trace copper ion in drinking water and tea samples for subsequent measurement by flame atomic absorption spectrometry (FAAS). The copper ions are adsorbed quantitatively during passage of aqueous solutions through Amberlyst 36 cation exchange resin. After the separation and preconcentration stage, the analyte was eluted with a potassium cyanide solution and determined by FAAS. Different factors including pH of sample solution, sample volume, amount of resin, flow rate of aqueous solution, volume and concentration of eluent, and matrix effects for preconcentration were examined. The analytical figures of merit for the determination of copper are as follows: analytical detection limit (3 σ), 0.26 μg/L; precision (RSD), 3.1% for 100 μg/L; enrichment factor, 200 (using 1000 mL of sample solution and 5 mL of eluent); time of analysis, 3.5 h (for obtaining enrichment factor of 200); capacity of resin, 125 mg/g. The method was applied for copper determination by FAAS in tap water, commercial natural spring water, commercial treated drinking water, and commercial tea bag sample. The accuracy of the method is confirmed by analyzing tea leaves (GBW 07605). The results demonstrated good agreement with the certified values.
Determination of pKa values by capillary zone electrophoresis with a dynamic coating procedure
Authors: Geiser Laurent , Henchoz Yveline , Galland Alexandra , Carrupt Pierre‐Alain , Veuthey Jean‐Luc 
Published: November 2005

AbstractCZE allows to measure the acidic dissociation constant (pK a) of many drug substances. However, determining the EOF intensity may be time‐consuming, especially at a low pH. In order to overcome this drawback, a dynamic coating procedure of the capillary was carried out to increase μEOF, and thus to reduce the analysis time. In addition, this coating procedure enhanced migration time stability. The effective mobilities of 15 compounds were measured at different pH, producing pK ′<?h ‐1.5dd>a values dependent on BGE ionic strength. The latter values were corrected with the activity coefficient to obtain a “true” pK a value. The 15 investigated compounds were (i) five acids: namely, salicylic acid, benzoic acid, ketoprofen, phenobarbital, and phenol, (ii) four bases: lidocaine, propafenone, propranolol, and quinine, (iii), five ampholytes: sulfanilamide, sulfabenzamide, sulfadimethoxine, sulfadoxine, and sulfisoxazole, and (iv) one zwitterion: cetirizine. The range of determined pK a values was between 1.2 and 11.2, and close to the pK a values available from the literature.
Twin-photon techniques for photo-detector calibration
Authors: Brida G , Genovese M , Gramegna M 
Published: November 2005

The aim of this review paper is to enlighten some recent progresses in quantum optical metrology in the part of quantum efficiency measurements of photo-detectors performed with bi-photon states.The intrinsic correlated nature of entangled photons from Spontaneous Parametric Down Conversion phenomenon has opened wide horizons to a new approach for the absolute measurement of photo-detector quantum efficiency, outgoing the requirement for conventional standards of optical radiation; in particular the simultaneous feature of the creation of conjugated photons led to a well known technique of coincidence measurement, deeply understood and implemented for standard uses.On the other hand, based on manipulation of entanglement developed for Quantum Information protocols implementations, a new method has been proposed for quantum efficiency measurement, exploiting polarisation entanglement in addition to energy-momentum and time ones, that is based on conditioned polarisation state manipulation.In this review, after a general discussion on absolute photo-detector calibration, we compare these different methods, in order to give an accurate operational sketch of the absolute quantum efficiency measurement state of the art.
Coating and near‐surface modification design strategies for protective and functional surfaces
Authors: Brady M.P. , Tortorelli P.F. , More K.L. , Payzant E.A. , Armstrong B.L. , Lin H.‐T. , Lance M.J. , Huang F. , Weaver M.L. 
Published: November 2005

AbstractThis paper discusses strategies for controlling the surface chemistry and microstructure of materials to form protective and functional surfaces through controlled gas‐metal reactions. Potential applications range from oxidation, corrosion, and wear resistance to electrochemical devices such as fuel cells to catalysts. Phenomenological examples are presented for coatings designed to self‐grade under oxidizing conditions, and for the growth of simple and complex (binary and ternary) nitride and carbide phase surface layers by nitridation and carburization reactions. Specific systems discussed include environmental barrier coatings (EBCs) for Si‐based ceramics such as Si3N4 and SiC, the growth of continuous, protective CrN/Cr2N, TiN, VN, NiNbVN, and related simple nitride layers on Fe‐ and Ni‐base alloys, the possible formation of ternary nitride and carbide surface phases (e.g. Ti3AlC2 and related MAX‐phases) on intermetallic surfaces to improve oxidation resistance, and the formation of composite near‐surface structures in Ag‐SiO2 and Co(Mo)‐Co6Mo6C2 systems.
Oxidation mechanisms of Cr‐containing steels and Ni‐base alloys at high‐temperatures –. Part I: The different role of alloy grain boundaries
Authors: Trindade V.B. , Krupp U. , Wagenhuber Ph. E.‐G. , Christ H.‐J. 
Published: November 2005

AbstractIt is essential for materials used at high‐temperatures in corrosive atmosphere to maintain their specific properties, such as good creep resistance, long fatigue life and sufficient high‐temperature corrosion resistance. Usually, the corrosion resistance results from the formation of a protective scale with very low porosity, good adherence, high mechanical and thermodynamic stability and slow growth rate. Standard engineering materials in power generation technology are low‐Cr steels. However, steels with higher Cr content, e.g., austenitic steels, or Ni‐base alloys are used for components applied to more severe service conditions, e.g., more aggressive atmospheres and higher temperatures. Three categories of alloys were investigated in this study. These materials were oxidised in laboratory air at temperatures of 550°C in the case of low‐alloy steels, 750°C in the case of an austenitic steel (TP347) and up to 1000°C in the case of the Ni‐base superalloys Inconel 625 Si and Inconel 718. Emphasis was put on the role of grain size on the internal and external oxidation processes. For this purpose various grain sizes were established by means of recrystallization heat treatment. In the case of low‐Cr steels, thermogravimetric measurements revealed a substantially higher mass gain for steels with smaller grain sizes. This observation was attributed to the role of alloy grain boundaries as short‐circuit diffusion paths for inward oxygen transport. For the austenitic steel, the situation is the other way round. The scale formed on specimens with smaller grain size consists mainly of Cr2O3 with some FeCr2O4 at localized sites, while for specimens with larger grain size a non‐protective Fe oxide scale is formed. This finding supports the idea that substrate grain boundaries accelerate the chromium supply to the oxide/alloy phase interface. Finally, in the Ni‐base superalloys deep intergranular oxidation attack was observed, taking place preferentially along random high‐angle grain boundaries.
Oxidation of FeCrAl alloys at 500–900°C in dry O2
Authors: Josefsson H. , Liu F. , Svensson J.‐E. , Halvarsson M. , Johansson L.‐G. 
Published: November 2005

AbstractThis paper reports on the oxidation of a commercial FeCrAl alloy, Kanthal AF, in the temperature range 500–900°C. The samples are exposed isothermally in dry oxygen for up to 72 h using a thermo‐balance. In addition, 168 h exposures are carried out in a tube furnace. The exposed samples are investigated by grazing angle X‐ray diffraction (XRD), scanning electron microscopy/energy dispersive X‐ray analysis (SEM/EDX), and auger electron spectroscopy (AES).The rate of oxidation increases with temperature, the kinetics being parabolic in the range 700–900°C. At all exposure temperatures, most of the sample surface is covered by a thin smooth base oxide. In addition, RE‐rich particles, with a typical size of 1–3 μm form. At 800 and 900°C patches of thick oxide appear, featuring needle‐formed crystallites situated on top of the base oxide. The thick oxide usually forms around Y‐rich oxide particles. The concentration of iron and chromium in the oxide decreases with increasing temperature. XRD proves the formation of α‐Al2O3 already at 700°C. The low temperature of formation of α‐Al2O3 is attributed to the presence of chromium in the initial oxide. It is proposed that corundum nucleation is facilitated on a surface consisting of the isostructural escolaite, (Cr2O3). After exposure at 900°C AES shows large amounts of Mg in the outer part of the oxide, MgAl2O4 being detected by XRD together with γ‐ and γ‐Al2O3.
Novel Aromatic Polymer Electrolyte with Comb‐like Structure: Synthesis and Properties
Authors: Li Yi , Yasuda Tomohiro , Miyatake Kenji , Watanabe Masahiro 
Published: November 2005

AbstractSummary: A novel aromatic polymer electrolyte with pendant sulfodecyloxy groups was synthesized. The monomer 4, bis[2‐(10′‐sulfodecyloxy)‐5‐chlorophenyl]sulfone, was synthesized from bis(2‐hydroxy‐5‐chlorophenyl)sulfide via bromoalkylation, oxidation, and sulfonation, and then polymerized via Ni‐catalyzed CC coupling polymerization to afford the title polymer electrolyte 6. The polymer 6 was isolated as a brown powder with molecular weight of $\overline M _{\rm w}$ = 12 000. The high decomposition temperature of 6 (200 °C) was confirmed by TG/DTA‐MS measurement. Proton conductivity of 6 was measured using porous polyimide membrane as a supporting substrate. The pore‐filled membrane showed 1 × 10−5 S · cm−1 of the proton conductivity at 80 °C and 90% RH.Synthesis of aromatic polymer electrolyte having sulfodecyloxy groups via nickel‐catalyzed CC coupling polymerization.magnified imageSynthesis of aromatic polymer electrolyte having sulfodecyloxy groups via nickel‐catalyzed CC coupling polymerization.
UV‐Induced Modification of Conjugated Polymers Using Gaseous Organosilanes
Authors: Buchgraber Christian , Spanring Julia , Kern Wolfgang , Pogantsch Alexander 
Published: November 2005

AbstractSummary: This paper describes the use of trialkylsilanes for photoinduced patterning of electroluminescent polymers as a new field of application for this type of organosilicon compounds. Under UV irradiation, trialkylsilanes selectively saturate the vinylene groups in poly(p‐phenylenevinylene) (PPV)‐type polymers, while leaving aromatic units virtually unaffected (selective photobleaching). Spin cast films of polymer blends consisting of two or three different conjugated polymers were UV irradiated in the presence of gaseous trialkylsilane reagents (trimethylsilane and ethyldimethylsilane) to achieve multicolor patterning. Exploiting the host‐guest concept with polyfluorene (PF) derivatives as totally aromatic host matrix and PPV derivatives as guest polymers, dual‐color displays and, with constraints, three‐color LED displays were realized. Compared to previously reported reagents such as hydrazine and thiols, trialkylsilanes enable photochemical patterning under non‐toxic and odorless conditions. Possible mechanisms for the photoreaction with trialkylsilanes as well as perspectives for applications are discussed.Electroluminescence spectra of LEDs based on the host‐guest system.magnified imageElectroluminescence spectra of LEDs based on the host‐guest system.
Polyhedral Oligomeric Silsesquioxane (POSS) Nanoscale Reinforcement of Thermosetting Resin from Benzoxazine and Bisoxazoline
Authors: Chen Qiao , Xu Riwei , Zhang Jun , Yu Dingsheng 
Published: November 2005

AbstractSummary: The reaction between octaaminophenyl polyhedral oligomeric silsesquioxane (OAPS) and 2,2′‐(1,3‐phenylene)‐bis(4,5‐dihydro‐oxazoles) (PBO) over different temperature ranges was confirmed by FT‐IR spectroscopy. The OAPS was used to modify benzoxazine (BZ) in the presence of PBO. The novel polybenzoxazine (PBZ)‐PBO/OAPS hybrid nanocomposite was prepared by solvent methods. Dynamic mechanical analyses indicated that the nanocomposites exhibited much higher Tg values than the pristine PBZ and PBZ‐PBO resin, and the storage modulus of the nanocomposites was maintained at higher temperatures, although only a small amount of OAPS was incorporated into the systems. Dynamic thermogravimetric analysis showed that the thermal stability of the hybrid was also improved by the inclusion of OAPS.DMA of PBZ (a), PBZ‐PBO (b), and PBZ‐PBO/OAPS nanocomposites (c–e).magnified imageDMA of PBZ (a), PBZ‐PBO (b), and PBZ‐PBO/OAPS nanocomposites (c–e).
High Temperature Free Radical Copolymerization with Depropagation and Penultimate Kinetic Effects
Authors: Li Deheng , Leiza Jose R. , Hutchinson Robin A. 
Published: November 2005

AbstractSummary: Methacrylate copolymers produced under higher temperature starved‐feed conditions are affected by depropagation, and some binary systems also experience a penultimate effect. In this work a generalized set of equations has been developed to describe the combined effect of depropagation and penultimate copolymerization kinetics on instantaneous copolymer composition and average copolymerization rate coefficients. Limiting cases applicable to the methacrylate/styrene system are examined. When combined with depropagation, penultimate kinetics not only decrease the effective propagation rate coefficient but also deviate from terminal model predictions of polymer composition.Copolymerization chain growth with penultimate kinetics and depropagation.magnified imageCopolymerization chain growth with penultimate kinetics and depropagation.
Global existence of solutions for 2‐D semilinear wave equations with dissipation localized near infinity in an exterior domain
Authors: Ikehata Ryo 
Published: November 2005

AbstractWe shall derive some global existence results to semilinear wave equations with a damping coefficient localized near infinity for very special initial data in H×L2. This problem is dealt with in the two‐dimensional exterior domain with a star‐shaped complement. In our result, a power p on the non‐linear term |u|p is strictly larger than the two‐dimensional Fujita‐exponent. Copyright © 2005 John Wiley & Sons, Ltd.
Study of ethanol‐induced conformational changes of holo and apo α‐lactalbumin by spectroscopy and limited proteolysis
Authors: Wehbi Zeina , Pérez María‐Dolores , Dalgalarrondo Michèle , Sánchez Lourdes , Calvo Miguel , Chobert Jean‐Marc , Haertlé Thomas 
Published: November 2005

AbstractThis study was performed to contribute to the analysis of α‐lactalbumin “molten globule” state by using spectral and proteolysis techniques. Samples of holo and apo α‐lactalbumin in the presence of different concentrations of ethanol were analyzed. Results of fluorescence spectroscopy of both forms showed that as ethanol concentration increased, the tryptophanyl residues became more accessible to the solvent. Near circular dichroism spectra of holo α‐lactalbumin indicated that its tertiary structure was maintained in 20% ethanol whereas it was altered in 30 and 40% ethanol. For apo α‐lactalbumin, spectra were similar in all samples studied. Holo α‐lactalbumin was resistant to trypsinolysis in 0% ethanol, whereas it was easily hydrolyzed in 20 and 30% ethanol. In the case of the apo form and in the absence of ethanol, 70% of the protein was degraded after 1 h. However, in the presence of 20 and 30% ethanol, the overall reaction rate was lowered. Peptides obtained after tryptic hydrolysis were identified by reversed‐phase high‐performance liquid chromatography coupled to mass spectrometry. Differences in population of produced peptides indicate the changes of folding intermediates present in the studied α‐lactalbumin solutions. This study demonstrated that proteolytic enzymes are suitable tools to determine protein structure complementing physico‐chemical studies.
Anthocyanidins decrease endothelin‐1 production and increase endothelial nitric oxide synthase in human endothelial cells
Authors: Lazzè Maria Claudia , Pizzala Roberto , Perucca Paola , Cazzalini Ornella , Savio Monica , Forti Luca , Vannini Vanio , Bianchi Livia 
Published: November 2005

AbstractEpidemiological and intervention studies correlate anthocyanin‐rich beverages and a low incidence of coronary heart diseases. Since endothelin‐1 (ET‐1) and nitric oxide (NO) produced by endothelial NO synthase (eNOS) are vascular tension regulators secreted by endothelial cells, we studied the influence of two anthocyanidins, namely cyanidin (CY) and delphinidin (DP), on the regulation of ET‐1 and eNOS in cultured human umbilical vein endothelial cells (HUVECs). Aglycon anthocyanidin forms, such as CY and DP, may be presentin vivoafter the first deglycosylation step occurring in the jejunum and in the liver. DP showed a major action compared to CY inducing a significant dose‐dependent inhibitory effect on both protein and mRNA levels of ET‐1. CY and DP both increased the protein level of eNOS, but DP showed the major effect raising eNOS protein in a dose‐dependent manner. To correlate the vasoprotective effect of CY and DP with their antioxidant activity, we analysed also the antioxidant effect of anthocyanidins bothin vitroand in HUVECs. In particular, we examined the effect of anthocyanidins on endothelial heme oxygenase‐1 (HO‐1), an inducible stress protein. In all tests, DP showed a higher antioxidant activity than CY. Finally, the antiproliferative effect induced by DP was detected in HUVECs. DP and CY differ in the number and position of hydroxyl groups in their structure; therefore, the greater biological activity by DP, compared with CY, seems to be due to the presence of the three hydroxyl groups on the B ring in the molecular structure of DP.
Cloning of oleosin, a putative new hazelnut allergen, using a hazelnut cDNA library
Authors: Akkerdaas Jaap H. , Schocker Frauke , Vieths Stefan , Versteeg Serge , Zuidmeer Laurian , Hefle Sue L. , Aalberse Rob C. , Richter Klaus , Ferreira Fatima , van Ree Ronald 
Published: November 2005

AbstractThe clinical presentation of non‐pollen related allergy to hazelnut can be severe and systemic. So far, only a limited number of non‐pollen related hazelnut allergens have been identified and characterized. The aim of this study was to identify and clone new hazelnut allergens. A lambda ZAP cDNA library of hazelnut was constructed. The library was screened with serum of six hazelnut allergic patients displaying different IgE‐binding patterns on hazelnut immunoblot. Rapid amplification of cDNA ends (RACE) protocols were applied to obtain full‐length clones. Expression experiments were carried out in Eschericchia coli. Expression was monitored by SDS‐PAGE, protein staining and immunoblotting. A hazelnut cDNA library was constructed. IgE screening resulted in the cloning of two isoforms of a novel putative hazelnut allergen. The clones were identified as oleosins, with theoretical molecular masses of 16.7 and 14.7 kDa and pI of 10.5 and 10.0, respectively. The isoforms demonstrated only 37% amino acid sequence identity but contained the typical hydrophobic stretch in the middle of the protein (53% identity) with the characteristic oleosin proline knot region (11/12 amino acids identical). Expression in E. coli of the longer isoform resulted in a clear band on SDS‐PAGE. The expressed protein was recognized on an immunodot blot by IgE from serum that was used for screening the cDNA library. Hazelnut contains multiple isoforms of oleosin. IgE binding of a hazelnut‐allergic patient to a recombinant version suggest that hazelnut oleosin is an allergen, as has been described for peanut and sesame.
Cell proliferation in the Rana catesbeiana auditory medulla over metamorphic development
Authors: Chapman Judith A. , Weinstein Joshua L. , Simmons Andrea Megela 
Published: November 2005

AbstractDuring metamorphic development, bullfrogs (Rana catesbeiana) undergo substantial morphological, anatomical, and physiological changes as the animals prepare for the transition from a fully‐aquatic to a semi‐terrestrial existence. Using BrdU incorporation and immunohistochemistry, we quantify changes in cell proliferation in two key auditory brainstem nuclei, the dorsolateral nucleus and the superior olivary nucleus, over the course of larval and early postmetamorphic development. From hatchling through early larval stages, numbers of proliferating cells increase in both nuclei, paralleling the overall increase in total numbers of cells available for labeling. Numbers of proliferating cells in the superior olivary nucleus decrease during the late larval and deaf periods, and significantly increase during metamorphic climax. Proliferating cells in the dorsolateral nucleus increase in number from hatchling to late larval stages, decrease during the deaf period, and increase during climax. In both nuclei, numbers of proliferating cells decrease during the postmetamorphic froglet stage, despite increases in the number of cells available for label. Newly generated cells express either glial‐ or neural‐specific phenotypes beginning between 1 week and 1 month post‐BrdU injection, respectively, while some new cells express γ‐aminobutyric acid within 2 days of mitosis. Our data show that these auditory nuclei dramatically up‐regulate mitosis immediately prior to establishment of a transduction system based on atmospheric hearing. © 2005 Wiley Periodicals, Inc. J Neurobiol, 2005