bluuebunny/crossref_metadata_2025 huggingface dataset:
A novel three-dose regimen of daclizumab in liver transplant recipients with hepatitis C: A pharmacokinetic and pharmacodynamic study
Authors: Washburn Kenneth W. , Teperman Lewis W. , Heffron Thomas G. , Douglas David D. , Gay Steven , Katz Eliezer , Klintmalm Goran B.G.
Published: February 2006

This study evaluated the pharmacokinetics and pharmacodynamics of a novel 3-dose regimen of daclizumab in de novo hepatitis C liver transplant recipients. In 30 of 156 recipients receiving daclizumab, mycophenolate mofetil, tacrolimus, and no steroids (Arm 3 of Hep C 3 Liver Study), daclizumab (2, 2, and 1 mg/kg, respectively) was given on days 1, 3, and 8 posttransplant, respectively, with trough, peak (Cmax), and CD25 saturation (CDsat) measured sequentially. Mean daclizumab Cmax was 50.3 μg/mL on day 1, and mean trough levels were 21.8, 25.7, and 9.9 μg/mL on days 3, 8, and 30, respectively. A significant decline in CDsat (mean, 15.7% to 4.7%) was observed on day 1 and was sustained throughout the study (2.8% on day 30). Daclizumab concentration ≥5 μg/mL was the level where most of the effect on CDsat was noticed. Elevated baseline CDsat was observed in African Americans, patients weighing ≤75 kg, and patients <60 years of age. After 365 days, 2 patients had experienced 3 rejections, 10 patients had recurrent hepatitis C, 4 patients died, and 2 grafts were lost. In conclusion, this novel 3-dose regimen is effective in rapidly achieving high therapeutic concentration of daclizumab and a significant decline in CDsat lasting over 30 days.
Liver Transpl 12:585–591, 2006.

© 2006 AASLD.
Novel pH Sensitive Block Copolymer Micelles for Solvent Free Drug Loading
Authors: Shim Woo Sun , Kim Sung Wan , Choi Eun‐Kyung , Park Heon‐Joo , Kim Jin‐Seok , Lee Doo Sung
Published: February 2006

Summary: Novel pH sensitive biodegradable block copolymers (MPEG‐PDLLA‐OSM) composed of mono‐methoxy poly(ethylene glycol) (MPEG), poly (D,L‐lactide) (PDLLA) and sulfamethazine oligomer (OSM) were synthesized via ring‐opening polymerization and a dicyclohexyl carboimide (DCC) coupling reaction. These copolymers had a relatively low critical micelle concentration (CMC) due to the strong hydrophobic properties of non‐ionized OSM at pH 7.0. Also, the pH sensitive block copolymers showed the micelle‐unimer transition due to the ionization‐non‐ionization of OSM in the pH range (pH 7.2–8.4) above the CMC. Due to the pH sensitive properties of the block copolymer, the hydrophobic drug paclitaxel (PTX) was incorporated into a pH sensitive block copolymer micelle by the pH induced micellization method, without using an organic solvent. The block copolymer micelle prepared by pH induced micellization showed a relatively high PTX loading efficiency, and good stability for 2 d at 37 °C. Furthermore, the PTX loaded micelle showed a sustained release of PTX with a small burst in vitro over 2 d. The present results suggest that the pH induced micellization method due to the micelle‐unimer transition of the pH sensitive block copolymer would be a novel and valuable drug incorporation tool for hydrophobic and protein drugs, since no organic solvent is involved in the formulation.

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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

Summary: 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 (•).

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Frontal 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

The 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

The 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

High 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

The 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

The 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

Low 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

Transmission 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

In 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

We 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

This 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

Let 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

The 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

Children 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

Peptide 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

In 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

The 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
Melting behaviors, crystallization kinetics, and spherulitic morphologies of poly(butylene succinate) and its copolyester modified with rosin maleopimaric acid anhydride
Authors: Liu Xiaoqing , Li Chuncheng , Zhang Dong , Xiao Yaonan
Published: February 2006

This article investigated the melting behaviors, crystallization kinetics, and spherulitic morphologies of poly(butylene succinate) (PBS) and its copolyester (PBSR) modified with rosin maleopimaric acid anhydride, using wide‐angle X‐ray diffraction, differential scanning calorimeter (DSC), and polarized optical microscope. Subsequent DSC scans of isothermally crystallized PBS and PBSR exhibited two melting endotherms, respectively, which was due to the melt‐recrystallization process occurring during the DSC scans. The equilibrium melting point of PBSR (125.9 °C) was lower than that of PBS (139 °C). The commonly used Avrami equation was used to describe the isothermal crystallization kinetics. For nonisothermal crystallization studies, the model combining Avrami equation and Ozawa equation was employed. The result showed a consistent trend in the crystallization process. The crystallization rate was decreased, the perfection of crystals was decreased, the recrystallization was reduced, and the spherulitic morphologies were changed when the huge hydrogenated phenanthrene ring was added into the chain of PBS. The activation energy (ΔE) for the isothermal crystallization process determined by Arrhenius method was 255.9 kJ/mol for PBS and 345.7 kJ/mol for PBSR. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 900–913, 2006
Probe Diagnostics of Expanding Plasmas at Low Gas Pressure
Authors: Dimitrova Mariya , Djermanova Nina , Kiss'ovski Zhivko , Kolev Stanimir , Shivarova Antonia , Tsankov Tsanko
Published: February 2006

Summary: Results from tandem‐type probe diagnostics of a plasma source based on an inductive discharge are presented in this study. The driver region is in the classical form of a cylindrically shaped inductive discharge, with a coil positioned over a gas discharge tube, whereas a bigger metal chamber provides volume for plasma expansion. Low pressure argon discharges were studied. The axial profiles of the plasma parameters were measured in the discharge in the metal chamber. The results obtained show that decreasing electron temperature and plasma density with increasing distance from the driver characterizes the behavior of the expanding plasmas. Moreover, two regions with different rates of variation of the plasma parameters complete the plasma expansion volume: a faster drop close to the driver and slow axial changes away from it. The gas pressure and power applied for the discharge maintenance were the external parameters varied.

Axial profiles of the electron concentration in the plasma expansion region of an inductive discharge.

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Axial profiles of the electron concentration in the plasma expansion region of an inductive discharge.
Conversion of Magnetron Deposited TiC Films into Rutile TiO2
Authors: Nikolova Petranka , Petkov Mario , Tinchev Savcho , Dyulgerska Juliana
Published: February 2006

Summary: TiO2 films can be obtained by a wide variety of technologies ranging from thermal oxidation, through PVD methods to a direct CVD growth. In this work, we report a two‐step fabrication of thin films of TiO2 (rutile). For the first time as a starting material were used TiC films deposited on monocrystalline silicon wafers by magnetron DC‐sputtering. The results of treatment of TiC thin films by an H2O/HCl gas mixture and Ar as a carrier gas at temperatures up to 1 000 °C and atmospheric pressure are presented. TiC films were converted into thin rutile films with traces of carbon. The microstructure and composition of the as‐deposited TiC films and of the films after treatment were investigated by scanning electron microscopy (SEM), by X‐ray diffraction (XRD) with a Co Kα (λ = 0.179 nm) and a Cu Kα source (λ = 0.154 nm) and by Raman spectroscopy.

A SEM image of the treated TiC film.

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A SEM image of the treated TiC film.
Pulsed Laser Deposition of SrBi2Ta2O9 Thin Films on Si Substrate
Authors: Tomov Rumen I. , Blamire Mark
Published: February 2006

Summary: Systematic study of pulsed laser deposition of non‐c‐axis‐oriented polycrystalline SrBi2Ta2O9 ferroelectric thin films on Pt‐coated silicon substrates has been performed. Both in situ and ex situ routes have been explored. Ex situ deposited films produced predominantly (115) and (200) orientations, while in situ deposition resulted in a mixture of (115) and (104) orientations. The growth was studied as a function of the ceramic targets Bi‐enrichment, target‐substrate distance, annealing temperature, and the utilization of an external electric field applied on the substrate during the post‐annealing procedure. Variation of those parameters appears to significantly affect the phase purity and crystalline quality of the films. The minimization of pyrochlore and fluorite phases and the related Bi2Pt formation have been achieved through the introduction of layered Bi‐enrichment gradient architecture and lowering the annealing temperature. SBT d33 piezoelectric coefficients of an order of 12–15 were measured. X‐ray diffraction was used to characterize structural perfection of the films. The nanoscale mechanism of piezoelectric behavior has been investigated by means of piezoresponse force microscopy.

Electromechanical hysteresis loops of SBT films.

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Electromechanical hysteresis loops of SBT films.
Surface Stoichiometry and Structural Properties of Copper‐Containing Sol–Gel SiO2 Films
Authors: Trapalis Christos , Kordas George , Osiceanu Petre , Ghita Adrian , Anastasescu Mihai , Crisan Maria , Anastasescu Crina , Zaharescu Maria
Published: February 2006

Summary: A study of the surface stoichiometry and structural properties of composite, copper‐containing, silica thin films (Cu:SiO2) is presented. The films are prepared on glass substrates by a sol–gel route. The coatings deposited by a dipping process are thermally treated under oxidative and subsequently reductive conditions up to 500 °C for metal nanoparticle formation. The coating structure, the nanoparticle formation, the copper diffusion, and the chemical composition of the surface are investigated using X‐ray diffraction (XRD), UV‐vis spectroscopy, heavy ion rutherford backscattering spectroscopy (HIRBS), and X‐ray photoelectron spectroscopy (XPS) as analytical methods.

HIRBS spectrum, showing the Cu distribution of samples studied: a) as prepared, b) after heating under oxidative, and c) after heating under reductive conditions, using 12C3+ ions at 10 MeV.

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HIRBS spectrum, showing the Cu distribution of samples studied: a) as prepared, b) after heating under oxidative, and c) after heating under reductive conditions, using 12C3+ ions at 10 MeV.
Electrical Properties of MIS Capacitors with AlN Films Synthesized by Pulsed Laser Deposition
Authors: Bakalova Silvia , Simeonov Simeon , Kafedjiiska Elisaveta , Szekeres Anna , Grigorescu Sorin , Socol Gabriel , Axente Emanuel , Mihailescu Ion
Published: February 2006

Summary: We manufactured for the first time MIS capacitors based on aluminium nitride (AlN) thin films synthesized by Pulsed Laser Deposition (PLD). AlN films were deposited on Si substrates by PLD from AlN targets in nitrogen ambient by multi‐pulse ablation using a UV KrF excimer laser source (λ = 248 nm, τ = 7 ns). The structures we prepared were electrically characterized by C‐V and I‐V complementary measurements. Our studies evidence the formation of good interfaces, and of defects into the film bulk which are electrically active. This justifies further developments in view of future applications of PLD synthesized AlN thin films as a dielectric alternatives to SiO2.

The distribution of the interface trap densities (Dit) in Si bandgap for AlN/Si structures synthesized at different N2 pressures.

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The distribution of the interface trap densities (Dit) in Si bandgap for AlN/Si structures synthesized at different N2 pressures.
Deposition and Properties of Thin (ZrO2)x(Al2O3)1‐x Films on Silicon
Authors: Vitanov Petko , Harizanova Antoaneta , Petrov Ivan , Alexieva Zvetana , Dimitrova Tatiana
Published: February 2006

Summary: This paper presents new results on the deposition technique and the characterization of thin (ZrO2)x(Al2O3)1‐x layers on silicon. The layers were deposited using the chemical solution deposition method on silicon substrates, and they were then subjected to different temperature treatments. For comparison, pure ZrO2 layers were deposited, too. The chemical composition of (ZrO2)x(Al2O3)1‐x layers is determined by Rutherford Back Scattering. The morphology was studied by HRSEM. The addition of Al2O3 makes the layers structurally more homogeneous as compared to those of pure ZrO2. The electric properties of MIS structures were studied. A fixed negative charge and the high dielectric constants are characteristic for these layers. The experimental results are discussed in the context of using them as high‐k dielectrics.

Quasistatic Cq, pulse Ch and 1 MHz C‐V curves of a MIS structure with a (ZrO2)x(Al2O3)1‐x film deposited on a silicon wafer and Hg dots.

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Quasistatic Cq, pulse Ch and 1 MHz C‐V curves of a MIS structure with a (ZrO2)x(Al2O3)1‐x film deposited on a silicon wafer and Hg dots.
Noncommutative QFT and renormalization
Authors: Grosse H. , Wulkenhaar R.
Published: February 2006

It was a great pleasure for me (Harald Grosse) to be invited to talk at the meeting celebrating the 70th birthday of Prof. Julius Wess. I remember various interactions with Julius during the last years: At the time of my studies at Vienna with Walter Thirring, Julius left already Vienna, I learned from his work on effective chiral Lagrangians. Next we met at various conferences and places like CERN (were I worked with Andre Martin, an old friend of Julius), and we all learned from Julius' and Bruno's creation of supersymmetry, next we realized our common interests in noncommutative quantum field theory and did have an intensive exchange. Julius influenced our perturbative approach to gauge field theories were we used the Seiberg‐Witten map after his advice. And finally I lively remember the sad days when during my invitation to Vienna Julius did have the serious heart attack. So we are very happy, that you recovered so well, and we wish you all the best for the forthcoming years. Many happy recurrences.
Gauge theories and non‐commutative geometry
Authors: Iliopoulos J.
Published: February 2006

It is shown that a d‐dimensional classical SU(N) Yang‐Mills theory can be formulated in a d+2‐dimensional space, with the extra two dimensions forming a surface with non‐commutative geometry.
A heterotic standard model
Authors: Ovrut B.A.
Published: February 2006

Within the context of the E8 × E8 heterotic superstring compactified on a smooth Calabi‐Yau threefold with an SU(4) gauge instanton, we show the existence of simple, realistic N = 1 supersymmetric vacua that are compatible with low energy particle physics. The observable sector of these vacua has gauge group SU(3)C × SU(2)L × U(1)Y × U(1)B‐L, three families of quarks and leptons, each with an additional right‐handed neutrino, two Higgs‐Higgs conjugate pairs, a small number of uncharged moduli and no exotic matter.
Supersymmetric black holes
Authors: de Wit B.
Published: February 2006

Recent insights from string theory and supergravity on the macroscopic and the microscopic description of black hole entropy are discussed.
Benchmarking of dimeric threading and structure refinement
Authors: Grimm Vera , Zhang Yang , Skolnick Jeffrey
Published: February 2006

The understanding of protein–protein interactions is a major goal in the postgenomic era. The prediction of interaction from sequence and the subsequent generation of full‐length dimeric models is therefore of great interest especially because the number of structurally characterized protein–protein complexes is sparse. A quality assessment of a benchmark comprised of 170 weakly homologous dimeric target–template pairs is presented. They are predicted in a two‐step method, similar to the previously described MULTIPROSPECTOR algorithm: each target sequence is assigned to a monomeric template structure by threading; then, those templates that belong to the same physically interacting dimer template are selected. Additionally we use structural alignments as the “gold standard” to assess the percentage of correctly assigned monomer and dimer templates and to evaluate the threading results with a focus on the quality of the alignments in the interfacial region. This work aims to give a quantitative picture of the quality of dimeric threading. Except for one, all monomer templates are identified correctly, but approximately 40% of the dimer templates are still problematic or incorrect. Preliminary results for three full‐length dimeric models generated with the TASSER method show on average a significant improvement of the final model over the initial template. Proteins 2006. © 2006 Wiley‐Liss, Inc.
Chemometric tools for classification and elucidation of protein secondary structure from infrared and circular dichroism spectroscopic measurements
Authors: Navea Susana , Tauler Romá , Goormaghtigh Erik , de Juan Anna
Published: February 2006

Protein classification and characterization often rely on the information contained in the protein secondary structure. Protein class assignment is usually based on X‐ray diffraction measurements, which need the protein in a crystallized form, or on NMR spectra, to obtain the structure of a protein in solution. Simple spectroscopic techniques, such as circular dichroism (CD) and infrared (IR) spectroscopies, are also known to be related to protein secondary structure, but they have seldom been used for protein classification. To see the potential of CD, IR, and combined CD/IR measurements for protein classification, unsupervised pattern recognition methods, Principal Component Analysis (PCA) and cluster analysis, are proposed first to check for natural grouping tendencies of proteins according to their measured spectra. Partial Least Squares Discriminant Analysis (PLS‐DA), a supervised pattern recognition method, is used afterwards to test the possibility to model explicitly each protein class and to test these models in class assignment of unknown proteins. Determination of the protein secondary structure, understood as the prediction of the abundance of the different secondary structure motifs in the biomolecule, was carried out with the local regression method interval Partial Least Squares (iPLS). CD, IR, and CD/IR measurements were correlated to the fraction of the motif to be predicted, determined from X‐ray measurements. iPLS builds models extracting the spectral information most correlated to a specific secondary motif and avoids the use of irrelevant spectral regions. Spectral intervals chosen by iPLS models provide structural information which can be used to confirm previous biochemical assignments or identify new motif‐related spectral features. The predictive ability of the models built with the selected spectral regions has a quality similar to previous classical approaches. Proteins 2006. © 2006 Wiley‐Liss, Inc.
TASSER‐based refinement of NMR structures
Authors: Lee Seung Yup , Zhang Yang , Skolnick Jeffrey
Published: February 2006

The TASSER structure prediction algorithm is employed to investigate whether NMR structures can be moved closer to their corresponding X‐ray counterparts by automatic refinement procedures. The benchmark protein dataset includes 61 nonhomologous proteins whose structures have been determined by both NMR and X‐ray experiments. Interestingly, by starting from NMR structures, the majority (79%) of TASSER refined models show a structural shift toward their X‐ray structures. On average, the TASSER refined models have a root‐mean‐square‐deviation (RMSD) from the X‐ray structure of 1.785 Å (1.556 Å) over the entire chain (aligned region), while the average RMSD between NMR and X‐ray structures (RMSDNMR_X‐ray) is 2.080 Å (1.731 Å). For all proteins having a RMSDNMR_X‐ray >2 Å, the TASSER refined structures show consistent improvement. However, for the 34 proteins with a RMSDNMR_X‐ray <2 Å, there are only 21 cases (60%) where the TASSER model is closer to the X‐ray structure than NMR, which may be due to the inherent resolution of TASSER. We also compare the TASSER models with 12 NMR models in the RECOORD database that have been recalculated recently by Nederveen et al. from original NMR restraints using the newest molecular dynamics tools. In 8 of 12 cases, TASSER models show a smaller RMSD to X‐ray structures; in 3 of 12 cases, where RMSDNMR_X‐ray <1 Å, RECOORD does better than TASSER. These results suggest that TASSER can be a useful tool to improve the quality of NMR structures. Proteins 2006. © 2006 Wiley‐Liss, Inc.
Surface morphology effects on the optical phonon modes in InAsxSb1–x epilayers on GaAs(001)
Authors: Jayavel P. , Nakamura S. , Kesavamoorthy R. , Srivastava G. P. , Tomoda W. , Koyama T. , Hayakawa Y.
Published: February 2006

We have studied Raman scattering from longitudinal‐ and transverse‐optical (LO and TO) phonon modes in InAsxSb1–x epilayers grown on GaAs(001) substrates with various arsenic compositions (x). InSb‐like and InAs‐like LO and TO phonon modes of the epilayers are observed. We find that the peak intensity ratio of the InAs‐like LO to TO‐mode decreases for x < 0.6 while it increases for x > 0.6. This intensity ratio change is attributed to two‐ and three‐dimensional (2D and 3D) growth mode of the epilayers using atomic force microscopy. Further, the intensity ratio depends on the root mean square surface roughness of the alloy. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optically detected electron spin‐flip resonance in CdMnTe
Authors: Zeng S. , Smith L. C. , Davies J. J. , Wolverson D. , Bingham S. J. , Aliev G. N.
Published: February 2006

We show that the spin‐flip of electrons at neutral donors in a dilute magnetic semiconductor can be observed directly by means of optically‐detected magnetic resonance (ODMR). Spectra obtained at 105 GHz for a bulk crystal of Cd1–x Mnx Te with x = 0.005 showed strong signals with g ‐values ranging between 12 (at 4.2 K) and 35 (at 1.7 K), with magnetic resonance linewidths ranging from 0.3 Tesla to 0.1 Tesla at the lowest temperature. In energy terms, these linewidths are independent of temperature and agree with those in spin‐flip Raman spectra from the same specimen. The line broadening is caused by fluctuations in the number of manganese ions that interact with a particular donor and an analysis of this leads to a value for the donor Bohr radius of 4.5 nm. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Estimation of n‐octanol/water Partition Coefficients (Kow) of all PCB Congeners by Ab initio and a Cl Substitution Position Method
Authors: Han Xiang‐Yun , Wang Zun‐Yao , Zhai Zhi‐Cai , Wang Lian‐Sheng
Published: February 2006

Optimized calculation of 209 PCBs was carried out at B3LYP/6‐31G* level in Gaussian98 program to obtain their structural parameters. It was found there is significant correlation between the Cl substitution position and some structural parameters such as α (r2=0.9972), EHOMO (r2=0.8874) etc. Consequently the numbers of Cl substitution positions (N) were taken as theoretical descriptors to establish the novel QSPR model for predicting n‐octanol/water partition coefficients (logKow) of all PCB congeners, which can be used directly without computation of their complex structural and thermodynamic parameters. The new model achieved in this work contains three variables, of which r2=0.9497 and q2=0.9465. In addition, the variation inflation factors (VIF) of variables in the present model are all less than 5.0, suggesting high accuracy of the logKow predicting model. And the results of cross‐validation test and method validation (r2=0.9640 and q2=0.9606) also showed the models of this study exhibited optimum stability, convenience for use and better predictive power than that from AM1 method.
A Linear QSPR Model for Prediction of Maximum Absorption Wavelength of Second‐order NLO Chromophores
Authors: Xu Jie , Zheng Zhi , Chen Biao , Zhang Qijin
Published: February 2006

The quantitative structure‐property relationship was studied between descriptors representing the molecular structures and λmax for a diverse set of 72 second‐order NLO chromophores. A linear ten‐parameter model was developed for the prediction of λmax with R2=0.9512 and SEE=22.95 by MLRA. The MRE for the calculation of λmax was 3.90%. The stability of the proposed model was validated using Leav‐Five‐Out cross‐validation and randomization experiments. All descriptors involved in the model were derived solely from the chemical structures of the NLO chromophores. A satisfactory MRE of 5.23% for a test set of 12 chromophores makes the model very useful for the prediction of the unknown chromophores.