bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

AbstractThis 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

AbstractSummary: 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.imageAxial 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

AbstractSummary: 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.imageA 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

AbstractSummary: 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.imageElectromechanical 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

AbstractSummary: 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.imageHIRBS 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

AbstractSummary: 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.imageThe 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

AbstractSummary: 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.imageQuasistatic 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

AbstractIt 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.
A heterotic standard model
Authors: Ovrut B.A. 
Published: February 2006

AbstractWithin 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.
Benchmarking of dimeric threading and structure refinement
Authors: Grimm Vera , Zhang Yang , Skolnick Jeffrey 
Published: February 2006

AbstractThe 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

AbstractProtein 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

AbstractThe 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

AbstractWe 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

AbstractWe 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

AbstractOptimized 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

AbstractThe 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.
Simultaneous quantitative determination of cyclosporine A and its three main metabolites (AM1, AM4N and AM9) in human blood by liquid chromatography/mass spectrometry using a rapid sample processing method
Authors: Koseki Nozomu , Nakashima Akinori , Nagae Yusuke , Masuda Naoki 
Published: February 2006

AbstractWe have developed a sensitive and specific liquid chromatography/mass spectrometry (LC/MS) method for the simultaneous determination of cyclosporine A (CsA) and its three main metabolites (AM1, AM4N and AM9) in human blood. Following protein precipitation, supernatant was directly injected into the LC/MS system. Chromatographic separation was accomplished on a Symmetry C8 (4.6 × 75 mm, 3.5 µm) column with a linear gradient elution prior to detection by atmospheric pressure chemical ionization (APCI) MS using selected ion monitoring (SIM) in positive mode. This method can be applied to single mass equipment. The analytical range for each analyte was set at 1–2500 ng/mL using 100 µL of blood sample. The analytical method was fully validated according to FDA guidance. Intra‐day mean accuracy and precision were 95.2–113.5% and 0.9–8.9%, respectively. Inter‐day mean accuracy and precision were 95.8–107.0% and 1.5–10.7%, respectively. In blood all analytes were stable during three freeze/thaw cycles, for 24 h at room temperature and for 12 months at or below −15°C. Stability was also confirmed in processed samples for 24 h at 10°C and for 6 months at 4°C in methanol. In addition, we confirmed the method could avoid matrix effects from transplant subjects' samples. This LC/MS technique provided an excellent method for simultaneous quantitative determination of CsA and its three metabolites for evaluation of their pharmacokinetic profiles. Copyright © 2006 John Wiley & Sons, Ltd.
2,5‐Dihydroxyacetophenone: a matrix for highly sensitive matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometric analysis of proteins using manual and automated preparation techniques
Authors: Wenzel Thomas , Sparbier Katrin , Mieruch Thorsten , Kostrzewa Markus 
Published: February 2006

Abstract2,5‐Dihydroxyacetophenone (DHAP) is presented as a matrix which enables highly sensitive matrix‐assisted laser desorption/ionization time‐of‐flight (MALDI‐TOF) mass spectrometric analysis of peptides, proteins and glycoproteins on AnchorChip targets. Depending on the protein, lower fmol amounts can be detected due to the increased homogeneity and concentration of the crystallization of the analyte/matrix mixture on the anchors. Best results could be generated in the mass range of 8–100 kDa. All sample/matrix preparation steps starting from mixing of DHAP matrix solution with sample solution to the transfer of the mixture to the MALDI‐TOF target can be performed manually or automatically allowing low‐ and high‐throughput analyses. Copyright © 2006 John Wiley & Sons, Ltd.
Skills training in telerobotic surgery
Authors: Hance J , Aggarwal R , Undre S , Darzi A 
Published: February 2006

AbstractSurgical robots have the potential to expand the repertoire of minimally invasive surgery resulting in more patients benefiting from lower operative morbidity and shorter hospital stays. However, in a similar manner to all new surgical interventions it necessary to explore the learning curves of practitioners as they adopt this new technology to enable optimisation of future training programs. Only when the standard of practice is firmly established, should the proliferation of robotic practitioners be encouraged thus ensuring patient safety is not compromised. Copyright © 2005 Robotic Publications, Ltd.