bluuebunny/crossref_metadata_2025_split huggingface dataset:
Boronate‐Containing Copolymers: Polyelectrolyte Properties and Sugar‐Specific Interaction with Agarose Gel
Authors: Kuzimenkova Marina V. , Ivanov Alexander E. , Galaev Igor Yu. 
Published: February 2006

AbstractSummary: Copolymers of N‐acryloyl‐m‐aminophenylboronic acid (NAAPBA) with acryamide (AA), N,N‐dimethylacrylamide (DMAA), and N‐isopropylacrylamide (NIPAM) were found to adsorb on cross‐linked agarose gel (Sepharose CL‐6B) in the pH range from 7.5–9.2, due to specific boronate‐sugar interactions. The molar percentages of phenylboronic acid (PBA) groups in the boronate‐containing copolymers (BCCs), as estimated by 1H NMR spectroscopy, were 13, 10, and 16%, respectively, whereas the apparent ionization constants, the pKa values, of the copolymers were similar and equal to 9.0 ± 0.2 at 20 °C. The copolymers adsorption capacities were in the range of 15–30 mg · ml−1 gel (14–36 µmol pendant PBA ml−1 gel) at pH 9.2 and decreased with decreasing pH value. The interaction of monomeric NAAPBA with Sepharose CL‐6B was characterized by an equilibrium association constant of 53 ± 17 M−1, the chromatographic capacity factor k′ = 1.8, and a total content of binding sites of 27 ± 10 µmol · ml−1 gel at pH 9.2. The weak reversible binding of monomeric NAAPBA and almost irreversible binding of NAAPBA copolymers to the gel at pH 9.2 suggested a multivalent character of the copolymer adsorption. At pH 7.5, the maximal adsorption capacity was displayed by the AA‐NAAPBA copolymer (15 mg · ml−1 gel). All the BCCs could be completely desorbed from the gel by 0.1 M fructose in aqueous buffered media with pH values from 7.5–9.2. The strong adsorption of AA‐NAAPBA on agarose gel probably relates to the conformation of the copolymer in aqueous solution and provides opportunities for biomedical applications of the copolymer under physiological conditions. Multivalent, weak‐affinity adsorption of BCCs to the agarose gel seems to be a tentative model for the copolymers' binding to oligo‐ and polysaccharides of cell membranes and mucosal surfaces.Frontal chromatogram of the AA‐NAAPBA copolymer (○) and polyacrylamide (•).magnified imageFrontal chromatogram of the AA‐NAAPBA copolymer (○) and polyacrylamide (•).
Oxidation behaviour of Fe‐Cr‐Al alloys during resistance and furnace heating
Authors: Echsler H. , Hattendorf H. , Singheiser L. , Quadakkers W. J. 
Published: February 2006

AbstractThe behaviour of thin Fe‐Cr‐Al heating element strips was investigated with respect to the oxidation limited life times and geometrical changes during resistance and furnace heating. For this purpose, isothermal and cyclic oxidation tests varying in their total exposure time and cycle duration were performed in the temperature range 1050–1200 °C. Specimens subjected to rapid cyclic, resistance heating revealed shorter life times than calculated for specimens subjected to isothermal exposure. The life times were found to increase with increasing cycle duration and hence decreasing number of cycles for a given time at temperature. This life time decrease is related to an “hour glass” waviness of the specimens, which develops during prolonged thermal cycling. The development of this plastic deformation also occurred during furnace heated, thermal cycling tests. A two‐step mechanism is introduced combining an oxidation kinetics related time to the onset of significant waviness with an enhancement of this waviness as a result of a ratcheting effect. The latter seems to strongly depend on the number of cycles and on the plastic deformation generated during each cycle rather than on the total time at temperature. The development of an “hour glass” waviness leads to an enhanced aluminium depletion due to an increase of the specimen surface area.Additional deformation phenomena like “hot tube” or “corkscrew” behaviour occur during the resistance heating tests. These are related to a temperature gradient that develops over the specimen width due to the poor aspect ratio of the specimens.
Service conditions and their influence on oxide scale formation on metallic high temperature alloys for application in innovative combustion processes
Authors: Teneva‐Kosseva G. , Ackermann H. , Köhne H. , Spähn M. , Richter S. , Mayer J. 
Published: February 2006

AbstractThe present paper focuses on two aspects: the service conditions of a flame tube in a low‐NOx recirculation burner (maximum temperature experienced by the material: 1000 °C) and the interrelationship between service conditions and both the structure and growth of the oxide scale. The flame tube is exposed to extreme thermal and atmospheric conditions during service. Due to the short burner operation time followed by a pause, rapid changes of the temperature and gaseous environment occur. Three Ni‐based alloys (alloy 602 CA, alloy 603 XL and alloy 693) were investigated in cyclic oxidation tests under typical conditions for the combustion of fuel oil. Flame tube temperature measurements in both the axial and the tangential directions are presented together with results concerning the influence of the fuel quality, duration of the air ventilation after burner shut down and temperature on the thickness and composition of the oxide scale.
Hot erosion wear and carburization in petrochemical furnaces
Authors: Deuis R. L. , Brown A. M. , Petrone S. 
Published: February 2006

AbstractHigh temperature alloy stainless steels used in olefins manufacturing furnaces are exposed to extreme environmental degradation processes inclusive of carburization, oxidation and hot erosion wear. A study was undertaken to understand the hot erosion wear phenomenon in relation to substrate composition, atmosphere, temperature, time and the influence of carburization. An erosion wear test rig was designed and constructed to simulate the wear degradation process up to 1200°C. Results have shown a surprising relationship between erosion wear rate and temperature for the most prominent stainless steel alloy used in the industry. A novel coating technology was developed for mitigation that enables the non‐line‐of‐sight application of protective macro‐coatings typically 1 to 5 mm in thickness. Stainless steel coupons treated with these macro‐coatings have exhibited an enhanced resistance to both oxidation and carburization. These macro‐coatings also provide superior hot erosion wear resistance as compared to the uncoated stainless steel. A thorough examination of the microstructure and micro‐mechanical properties of the coatings is presented. Targeted applications include petrochemical furnace fittings (return bends), thermo‐wells and transfer‐line‐exchanger (TLE) surfaces. Commercial furnace trials of the prototype products have been initiated with some prototypes in field trials for over 18 months. Results of both laboratory accelerated testing and field evaluation will be discussed.
High temperature corrosion of structural materials under gas‐cooled reactor helium
Authors: Cabet C. , Terlain A. , Lett P. , Guétaz L. , Gentzbittel J.‐M. 
Published: February 2006

AbstractThe Generation IV International Forum has selected six promising nuclear power systems for further collaborative investigations and development. Among these six concepts, two candidates are Gas Cooled Reactors (GCR), namely the Very High Temperature Reactor (VHTR) and the Gas‐cooled Fast Reactor (GFR). The CEA has launched a R&D program on the metallic materials for application in an innovative GCR. Structural GCR alloys have been extensively studied in the past three decades. Some critical aspects for the steels and nickel base alloys resistance under the service conditions are microstructural stability, creep strength and compatibility with the cooling gas. The coolant, namely helium, proved to contain impurities mainly H2, CO, CH4, N2 and steam in the microbar range that interact with metals at high temperature. Surface scale formation, bulk carburisation and/or decarburisation can occur, depending on the atmosphere characteristics, primarily the effective oxygen partial pressure and carbon activity, on the temperature and on the alloys chemical composition. These structural transformations can notably influence the mechanical properties: carburisation may induce a loss in toughness and ductility whereas decarburisation impedes the creep strength.There is a valuable theoretical as well as practical knowledge on the corrosion of high temperature alloys in the primary circuit of a GCR but this past experience is not sufficient to qualify every component in a future reactor. On the one hand, the material environment could be significantly different from the former GCR's, especially regarding the higher temperature. On the other hand, the materials of interest are partly different. Ni‐Cr‐W alloys, for instance, may offer significant improvement in the maximum operating temperature as far as the mechanical properties are concerned. However, their corrosion resistance toward the GCR atmosphere is still unknown.We describe here our first corrosion tests of Haynes 230, a high strength Ni base alloy containing tungsten, under low oxidising helium at 750 °C or 950 °C. The experiments were carried out in a purposely‐designed device that allows controlling low impurity partial pressure. The test duration was up to 1000 h. The corrosion behaviour was assessed through gravimetry and microscopy. Some specimens were investigated using EDS and DRX. The results under low oxidizing potential are compared to the oxidation kinetics in air. Tentative interpretations are proposed based on published models.
Study of the oxide scale integrity on Ni‐base alloy CMSX‐4 during isothermal and thermal‐cycling exposure
Authors: Orosz R. , Krupp U. , Christ H.‐J. 
Published: February 2006

AbstractThe excellent isothermal high‐temperature corrosion resistance of the single crystalline Ni‐base superalloy CMSX‐4, which is due to external alumina formation, is substantially reduced under thermal‐cycling conditions. Particularly, tapered edges exhibit a high cracking and spallation rate leading to premature onset of breakaway oxidation in combination with strong internal corrosion attack. To characterize these effects, specimens with different geometries were prepared, i.e., rectangular‐shaped and wedge‐shaped specimens. Measurements under isothermal and thermal‐cycling conditions at a temperature of 1100°C in air were carried out using a self‐designed thermobalance. By using wedge‐shaped specimens the conditions for spallation, Al depletion and eventually, breakaway oxidation in combination with internal corrosion (Al2O3, TiN and AlN) could be correlated with the change in thickness of the specimen and the duration of the high‐temperature dwell time. As compared to rectangular‐shaped specimens, wedge geometries revealed a much higher susceptibility to oxide spallation and consequently, a higher rate of aluminium depletion. An evaluation of the surface fraction affected by oxide spallation and an analysis of the spalled oxidation products were carried out in order to determine the role of dwell time duration as well as the effect of the number of thermal cycles.
Cyclic oxidation testing of P91 in low velocity burner rigs
Authors: Osgerby S. , Banks J.P. , Brown L.J. 
Published: February 2006

AbstractLow velocity burner rigs have been used to perform cyclic oxidation tests. Due to the nature of the equipment there are limitations on the cycle frequency that can be used and there are also several other parameters that must be defined. The importance of these parameters on metal wastage in the martensitic steel, P91 has been investigated.Salt deposition rates are independent of fuel and salt composition under the conditions investigated. However the observed metal wastage in the martensitic steel P91 is influenced both by the fuel and salt compositions. Intermittent washing of the specimens has little influence whilst the corrosion product remains intact but causes additional loss of corrosion product after spallation has been initiated.
The approaches to thin film preparation and TEM observations on slurry Si‐modified aluminide coatings
Authors: Shirvani K. , Saremi M. , Yamamoto Y. 
Published: February 2006

AbstractTransmission electron microscopy (TEM) can be used as a precision characterization tool to identify very small precipitates in diffusion aluminide coatings. However, in order to successfully prepare the appropriate samples for TEM observation, often non‐traditional thin film preparation techniques need to be employed. In this work, two sample preparation methods of twin jet electro‐polishing and ion milling were experienced to characterize fine precipitates (< 1 μm), in Si‐aluminide coatings applied on Ni‐base superalloy In‐738LC by slurry technique. These precipitates are concentrated throughout the topcoat zone. It was found that the preparation of thin film exactly from the outer zone of the coating is only possible using ion milling process. The ion‐milled specimens were utilized to observe by JEOL high resolution TEM operating at an accelerating voltage of 300 kV. Electron diffraction patterns, bright field and EDS were used to identify the precipitate phases as well as the coating matrix. The results showed that the fine precipitates are typically chromium silicides in nature, mostly as Cr3Si and CrSi, distributed in the β‐NiAl matrix phase.
Generalized Stokes resolvent equations in an infinite layer with mixed boundary conditions
Authors: Abels Helmut 
Published: February 2006

AbstractIn this paper we prove unique solvability of the generalized Stokes resolvent equations in an infinite layer Ω0 = ℝn –1 × (–1, 1), n ≥ 2, in Lq ‐Sobolev spaces, 1 < q < ∞, with slip boundary condition of on the “upper boundary” ∂Ω+0 = ℝn –1 × {1} and non‐slip boundary condition on the “lower boundary” ∂Ω–0 = ℝn –1 × {–1}. The solution operator to the Stokes system will be expressed with the aid of the solution operators of the Laplace resolvent equation and a Mikhlin multiplier operator acting on the boundary. The present result is the first step to establish an Lq ‐theory for the free boundary value problem studied by Beale [9] and Sylvester [22] in L 2‐spaces. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Solvability on the Heisenberg group
Authors: Eremiev Karadzhov G. 
Published: February 2006

AbstractWe solve in various spaces the linear equations Lαg = f , where Lα belongs to a class of transversally elliptic second order differential operators on the Heisenberg group with double characteristics and complex‐valued coefficients, not necessarily locally solvable. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
General Littlewood–Paley functions and singular integral operators on product spaces
Authors: Wu Huoxiong 
Published: February 2006

AbstractThis paper is devoted to the study on the Lp ‐mapping properties for certain singular integral operators with rough kernels and related Littlewood–Paley functions along “polynomial curves” on product spaces ℝm × ℝn (m ≥ 2, n ≥ 2). By means of the method of block decomposition for kernel functions and some delicate estimates on Fourier transforms, the author proves that the singular integral operators and Littlewood–Paley functions are bounded on Lp (ℝm × ℝn ), p ∈ (1, ∞), and the bounds are independent of the coefficients of the polynomials. These results essentially improve or extend some well‐known results. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Weighted estimates for maximal multilinear commutators
Authors: Zhang Pu 
Published: February 2006

AbstractLet T be a Calderón–Zygmund operator with regular kernel K and T *b be the maximal multilinear commutator defined by
equation image
. In this paper, the following weighted estimates for T *b are discussed. Precisely, for 0 < p < ∞, ω ∈ A ∞ and b j ∈ Osc , rj ≥ 1, j = 1, … , m , there exists a positive constant C such that
equation image
.For p = 1 and ω ∈ A 1, the weighted weak L (log L )1/r ‐type estimates are also established.Our theorems are parallel to the ones of the multilinear commutators of Calderón–Zygmund operators obtained in [18] and extend the main result in [14] essentially. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Simulation of hypersonic flows on unstructured grids
Authors: Selmin V. , Formaggia L. 
Published: February 2006

AbstractThe paper describes a solver for the compressible inviscid flow equations which is based on a flux vector splitting strategy able to deal with chemical reaction effects. The methodology here adopted is based on a modification of the Flux Vector Splitting technique due to van Leer.11 The scheme operates on completely unstructured grids and has been coupled with an adaptive remeshing procedure to compute high speed flows. Solutions for two‐dimensional problems for non‐reactive and reactive air in thermodynamic equilibrium are presented.
Stress lysis in childhood leukemia
Authors: Adamson Peter C. 
Published: February 2006

AbstractChildren with acute lymphoblastic leukemia (ALL) can experience a decrease in their white blood count (WBC) prior to chemotherapy, a phenomenon commonly attributed to the administration of allopurinol and hydration. We reviewed the records of 20 children with newly diagnosed ALL prior to the administration of allopurinol and found that 80% of patients experienced a decrease in their WBC (median decrease 14,000/mm3) in the less than 24‐hr interval between evaluation at the referring center and admission to our hospital (P = 0.002). The basis for this often‐observed phenomenon appears to be that leukemic cells rapidly lyse in response to the stress‐induced release of endogenous corticosteroids. Pediatr Blood Cancer 2008;50:137–139. © 2006 Wiley‐Liss, Inc.
Functional peptide microarrays for specific and sensitive antibody diagnostics
Authors: Andresen Heiko , Grötzinger Carsten , Zarse Kim , Kreuzer Oliver J. , Ehrentreich‐Förster Eva , Bier Frank F. 
Published: February 2006

AbstractPeptide microarrays displaying biologically active small synthetic peptides in a high‐density format provide an attractive technology to probe complex samples for the presence and/or function of protein analytes. We present a new approach for manufacturing functional peptide microarrays for molecular immune diagnostics. Our method relies on the efficiency of site‐specific solution‐phase coupling of biotinylated synthetic peptides to NeutrAvidin (NA) and localized microdispensing of peptide‐NA‐complexes onto activated glass surfaces. Antibodies are captured in a sandwich manner between surface immobilized peptide probes and fluorescence‐labeled secondary antibodies. Our work includes a total of 54 peptides derived from immunodominant linear epitopes of the T7 phage capsid protein, Herpes simplex virus glycoprotein D, c‐myc protein, and three domains of the Human coronavirus polymerase polyprotein and their cognate mAbs. By using spacer molecules of different type and length for NA‐mediated peptide presentation, we show that the incorporation of a minimum spacer length is imperative for antibody binding, whereas the peptide immobilization direction has only secondary importance for antibody affinity and binding. We further demonstrate that the peptide array is capable of detecting low‐picomolar concentrations of mAbs in buffered solutions and diluted human serum with high specificity.
SPLASH: Systematic proteomics laboratory analysis and storage hub
Authors: Lo Siaw Ling , You Tao , Lin Qingsong , Joshi Shashikant B. , Chung Maxey C. M. , Hew Choy Leong 
Published: February 2006

AbstractIn the field of proteomics, the increasing difficulty to unify the data format, due to the different platforms/instrumentation and laboratory documentation systems, greatly hinders experimental data verification, exchange, and comparison. Therefore, it is essential to establish standard formats for every necessary aspect of proteomics data. One of the recently published data models is the proteomics experiment data repository [Taylor, C. F., Paton, N. W., Garwood, K. L., Kirby, P. D. et al., Nat. Biotechnol. 2003, 21, 247–254]. Compliant with this format, we developed the systematic proteomics laboratory analysis and storage hub (SPLASH) database system as an informatics infrastructure to support proteomics studies. It consists of three modules and provides proteomics researchers a common platform to store, manage, search, analyze, and exchange their data. (i) Data maintenance includes experimental data entry and update, uploading of experimental results in batch mode, and data exchange in the original PEDRo format. (ii) The data search module provides several means to search the database, to view either the protein information or the differential expression display by clicking on a gel image. (iii) The data mining module contains tools that perform biochemical pathway, statistics‐associated gene ontology, and other comparative analyses for all the sample sets to interpret its biological meaning. These features make SPLASH a practical and powerful tool for the proteomics community.
Block copolymer mediated synthesis of amphiphilic gold nanoparticles in water and an aqueous tetrahydrofuran medium: An approach for the preparation of polymer–gold nanocomposites
Authors: Jewrajka Suresh K. , Chatterjee Uma 
Published: February 2006

AbstractThe synthesis of polymer‐matrix‐compatible amphiphilic gold (Au) nanoparticles with well‐defined triblock polymer poly[2‐(N,N‐dimethylamino)ethyl methacrylate]‐b‐poly(methyl methacrylate)‐b‐poly[2‐(N,N‐dimethylamino)ethyl methacrylate] and diblock polymers poly(methyl methacrylate)‐b‐poly[2‐(N,N‐dimethylamino)ethyl methacrylate], polystyrene‐b‐poly[2‐(N,N‐dimethylamino)ethyl methacrylate], and poly(t‐butyl methacrylate)‐b‐poly[2‐(N,N‐dimethylamino)ethyl methacrylate] in water and in aqueous tetrahydrofuran (tetrahydrofuran/H2O = 20:1 v/v) at room temperature is reported. All these amphiphilic block copolymers were synthesized with atom transfer radical polymerization. The variations of the position of the plasmon resonance band and the core diameter of such block copolymer functionalized Au particles with the variation of the surface functionality, solvent, and molecular weight of the hydrophobic and hydrophilic parts of the block copolymers were systematically studied. Different types of polymer–Au nanocomposite films [poly(methyl methacrylate)–Au, poly(t‐butyl methacrylate)–Au, polystyrene–Au, poly(vinyl alcohol)–Au, and poly(vinyl pyrrolidone)–Au] were prepared through the blending of appropriate functionalized Au nanoparticles with the respective polymer matrices {e.g., blending poly[2‐(N,N‐dimethylamino)ethyl methacrylate]‐b‐poly(methyl methacrylate)‐b‐poly[2‐(N,N‐dimethylamino)ethyl methacrylate‐stabilized Au with the poly(methyl methacrylate)matrix only}. The compatibility of specific block copolymer modified Au nanoparticles with a specific homopolymer matrix was determined by a combination of ultraviolet–visible spectroscopy, transmission electron microscopy, and differential scanning calorimetry analyses. The facile formation of polymer–Au nanocomposites with a specific block copolymer stabilized Au particle was attributed to the good compatibility of block copolymer coated Au particles with a specific polymer matrix. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 1841–1854, 2006