bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pressure effects in lutetium yttrium oxyorthosilicate single crystals
Authors: Ricci Pier Carlo , Chiriu Daniele , Carbonaro Carlo Maria , Desgreniers Serge , Fortin Emery , Anedda Alberto 
Published: April 2008

AbstractThe Raman scattering from Lu1.8Y0.2SiO5 single crystals was investigated for quasi‐hydrostatic pressures ranging from atmospheric to about 15 GPa at room temperature. The material, originally belonging to the monoclinic C2/c structure, transforms gradually to a higher‐density phase upon the application of pressure. Unit cell volume, peak position, and the Grüneisen parameter have been calculated and analyzed, revealing three different pressure regimes. The first low‐pressure regime relates mainly to the change of unit cell volume. In the second pressure regime, the gradual phase transformation starts at about 3 GPa and is completed at a pressure of 10 GPa. The third pressure regime part reveals a sensibly lower pressure dependence. A detailed analysis of the data allowed us to propose a scheme for a pressure‐induced gradual phase transition, resulting in the coexistence of phases over a wide pressure range. Moreover, the material reverts to the ambient‐condition phase upon release of pressure, showing an almost total reversibility. By comparison with the vibrational spectra of the pure Y2SiO5 compound and from the analysis of the crystal structures, the pressure‐induced high‐density phase is assigned to the P21/c monoclinic structure, typical of oxyorthosilicates. Copyright © 2008 John Wiley & Sons, Ltd.
Time‐resolved resonance Raman and density functional theory study of the deprotonation reaction of the triplet state of para‐hydroxybenzophenone in mixed acetonitrile/water solutions
Authors: Du Yong , Xue Jiadan , Ma Chensheng , Ming Kwok Wai , Lee Phillips David 
Published: April 2008

AbstractNanosecond time‐resolved resonance Raman (ns‐TR3) spectroscopy was employed to investigate the triplet state of para‐hydroxybenzophenone (p‐hBP) in pure acetonitrile (MeCN) and its subsequent deprotonation reaction in a H2O/MeCN mixed solution. The TR3 results reveal that the deprotonation reaction occurred with the p‐hBP triplet state as the precursor species after 266 nm photolysis of p‐hBP in a H2O/MeCN mixed solution. The ground‐state p‐hBP anion species was observed to form about 20 ns after excitation in a 5% H2O/95% MeCN mixed solvent. Density functional theory (DFT) calculations were done to help obtain information about the structures and vibrational modes of the triplet p‐hBP and p‐hBP anion species. A reaction scheme is proposed for the photoreaction pathways of p‐hBP in pure MeCN and H2O/MeCN mixed solvents. Comparison of the results here for p‐hBP to the related para‐hydroxyacetophenone (HA) system indicates that substitution of the methyl group in HA with a phenyl group to form p‐hBP significantly alters the chemical reactivity of the triplet state so that both deprotonation and intersystem crossing (ISC) for the triplet state occur much faster in p‐hBP than in HA. Copyright © 2008 John Wiley & Sons, Ltd.
Plasmon‐enhanced polarized Raman spectroscopy for sensitive surface characterization
Authors: Kasim J. , Tee X. Y. , You Y. M. , Ni Z. H. , Setiawan Y. , Lee P. S. , Chan L. , Shen Z. X. 
Published: April 2008

AbstractLocal‐mode and localized surface plasmons generated on the silver thin film can selectively enhance the Raman signal from the surface. Further improvement of surface signal can be obtained by using the polarized Raman technique that results in a dramatic enhancement of the surface sensitivity by up to 25.4 times as compared to that without a silver coating. This technique will be very useful for Raman study on samples that suffer overlapping background signal. In this article, we show that it can be used to significantly improve the signal of thin strained‐Si layer on top of SiGe buffer layer. Copyright © 2008 John Wiley & Sons, Ltd.
Fatty acid and fat‐soluble antioxidant concentrations in milk from high‐ and low‐input conventional and organic systems: seasonal variation
Authors: Butler Gillian , Nielsen Jacob H , Slots Tina , Seal Chris , Eyre Mick D , Sanderson Roy , Leifert Carlo 
Published: April 2008

AbstractBACKGROUND: Previous studies showed differences in fatty acid (FA) and antioxidant profiles between organic and conventional milk. However, they did not (a) investigate seasonal differences, (b) include non‐organic, low‐input systems or (c) compare individual carotenoids, stereoisomers of α‐tocopherol or isomers of conjugated linoleic acid. This survey‐based study compares milk from three production systems: (i) high‐input, conventional (10 farms); (ii) low‐input, organic (10 farms); and (iii) low‐input non‐organic (5 farms). Samples were taken during the outdoor grazing (78 samples) and indoor periods (31 samples).RESULTS: During the outdoor grazing period, on average, milk from the low‐input systems had lower saturated FAs, but higher mono‐ and polyunsaturated FA concentrations compared with milk from the high‐input system. Milk from both the low‐input organic and non‐organic systems had significantly higher concentrations of nutritionally desirable FAs and antioxidants—conjugated linoleic (60% and 99%, respectively) and α‐linolenic (39% and 31%, respectively) acids, α‐tocopherol (33% and 50%, respectively) and carotenoids (33% and 80%, respectively)—compared with milk from the high‐input system. Milk composition differed significantly between the two low‐input systems during the second half of the grazing period only; with milk from non‐organic cows being higher in antioxidants, and conjugated linoleic acid, and that from organic cows in α‐linolenic acid. In contrast, few significant differences in composition were detected between high‐input and low‐input organic systems when cows were housed.CONCLUSIONS: Milk composition is affected by production systems by mechanisms likely to be linked to the stage and length of the grazing period, and diet composition, which will influence subsequent processing, and sensory and potential nutritional qualities of the milk. Copyright © 2008 Society of Chemical Industry
Diagnosis and management of desmoid tumors and fibrosarcoma
Authors: Wong Sandra L. 
Published: April 2008

AbstractFibrous tumors represent a diverse subtype of soft tissue tumors and can represent benign conditions as well as frankly malignant sarcomas. Desmoid tumors and dermatofibrosarcoma protuberans are more difficult to classify and tend to be considered in the intermediate risk category. They are distinct entities, but both are locally aggressive processes which are plagued with attendant morbidity and high recurrence rates. Complete surgical resection is the mainstay of treatment. J. Surg. Oncol. 2008;97:554–558. © 2008 Wiley‐Liss, Inc.
Comparative study among different neural net learning algorithms applied to rainfall time series
Authors: Chattopadhyay Surajit , Chattopadhyay Goutami 
Published: April 2008

AbstractThe present article reports studies to identify a non‐linear methodology to forecast the time series of average summer‐monsoon rainfall over India. Three advanced backpropagation neural network learning rules namely, momentum learning, conjugate gradient descent (CGD) learning, and Levenberg–Marquardt (LM) learning, and a statistical methodology in the form of asymptotic regression are implemented for this purpose. Monsoon rainfall data pertaining to the years from 1871 to 1999 are explored. After a thorough skill comparison using statistical procedures the study reports the potential of CGD as a learning algorithm for the backpropagation neural network to predict the said time series. Copyright © 2008 Royal Meteorological Society
Expression profile of male germ cell‐associated genes in mouse embryonic stem cell cultures treated with all‐trans retinoic acid and testosterone
Authors: Silva Celso , Wood Jennifer R. , Salvador Lisa , Zhang Zhibing , Kostetskii Igor , Williams Carmen J. , Strauss Jerome F. 
Published: April 2008

AbstractCells that morphologically and functionally resemble male germ cells can be spontaneously derived from ES cells. However, this process is inefficient and unpredictable suggesting that the expression pattern of male germ cell associated genes during spontaneous ES cell differentiation does not mimic the in vivo profiles of the genes. Thus, in the present study, the temporal profile of genes expressed at different stages of male germ cell development was examined in differentiating ES cells. The effect of all‐trans retinoic acid (RA) which is a known inducer of primordial germ cell (PGC) proliferation/survival in vitro and testosterone which is required for spermatogenesis in vivo on the expression of these genes was also determined. Each of the 12 genes analyzed exhibited one of four temporal expression patterns in untreated differentiating ES cells: progressively decreased (Dppa3, Sycp3, Msy2), initially low and then increased (Stra8, Sycp1, Dazl, Act, Prm1), initially decreased and then increased (Piwil2, Tex14), or relatively unchanged (Akap3, Odf2). RA‐treated cells exhibited increased expression of Stra8, Dazl, Act, and Prm1 and suppressed expression of Dppa3 compared to untreated controls. Furthermore, testosterone increased expression of Stra8 while the combination of RA and testosterone synergistically increased expression of Act. Our findings establish a comprehensive profile of male germ cell gene expression during spontaneous differentiation of murine ES cells and describe the capacity of RA and testosterone to modulate the expression of these genes. Furthermore, these data represent an important first step in designing a plausible directed differentiation protocol for male germ cells. Mol. Reprod. Dev. 76: 11–21, 2009. © 2008 Wiley‐Liss, Inc.
The timing of insulin administration to hospital inpatients is unsafe: patient self‐administration may make it safer
Authors: Gangopadhyay KK , Ebinesan AD , Mtemererwa B , Marshall C , Mcgettigan AT , Cope A , Narendran P 
Published: April 2008

AbstractIt is routine practice for insulin to be administered by hospital staff to diabetic inpatients who would normally self‐inject at home. The accuracy of this practice has not been clearly evaluated. Our audit aimed to evaluate the accuracy of insulin administration times, patient preference and the possibility of self‐administration by hospitalised patients.Information on patient preferences, and the timing of meals and insulin administration, was collected for insulin‐treated diabetic inpatients whose insulin was administered by hospital staff (Group 1), and for another group whose insulin was self‐administered (Group 2).In Group 1 (175 meals, 25 patients), only 19% of insulin administration times were deemed accurate. In this Group, 15/21 patients wanted to self‐inject in hospital. In Group 2 (10 patients, 73 meals), the timing of 57/73 (78%) insulin self‐administrations was accurate, and the remaining errors were often not through patient fault.The timing of insulin administration to hospitalised patients needs to be improved. An option may be to allow selected patients to self‐administer their insulin. Copyright © 2008 John Wiley & Sons.
Comparison of the extracellular proteomes of Escherichia coli B and K‐12 strains during high cell density cultivation
Authors: Xia Xiao‐Xia , Han Mee‐Jung , Lee Sang Yup , Yoo Jong‐Shin 
Published: April 2008

AbstractEscherichia coli BL21 (DE3) and W3110 strains, belonging to the family B and K‐12, respectively, have been most widely employed for recombinant protein production. During the excretory production of recombinant proteins by high cell density cultivation (HCDC) of these strains, other native E. coli proteins were also released. Thus, we analyzed the extracellular proteomes of E. coli BL21 (DE3) and W3110 during HCDC. E. coli BL21 (DE3) released more than twice the amount of protein compared with W3110 during HCDC. A total of 204 protein spots including 83 nonredundant proteins were unambiguously identified by 2‐DE and MS. Of these, 32 proteins were conserved in the two strains, while 20 and 33 strain‐specific proteins were identified for E. coli BL21 (DE3) and W3110, respectively. More than 70% of identified proteins were found to be of periplasmic origin. The outer membrane proteins, OmpA and OmpF, were most abundant. Two strains showed much different patterns in their released proteins. Also, cell density‐dependent variations in the released proteins were observed in both strains. These findings summarized as reference proteome maps will be useful for studying protein release in further detail, and provide new strategies for enhanced excretory production of recombinant proteins.
A short peptide is a protein kinase C (PKC) α‐specific substrate
Authors: Kang Jeong‐Hun , Asai Daisuke , Yamada Satoshi , Toita Riki , Oishi Jun , Mori Takeshi , Niidome Takuro , Katayama Yoshiki 
Published: April 2008

AbstractThe purpose of this study was to find protein kinase C (PKC) isozyme‐specific peptides. A peptide library containing 1772 sequences was designed using Scansite and screened by MALDI‐TOF MS and kinase activity assays for PKC isozyme‐specificity. A peptide (Alphatomega; H‐FKKQGSFAKKK‐NH2) with high specificity for PKCα relative to other isozymes was identified. The peptide was phosphorylated to a greater extent by tissue lysates from B16 melanoma, HepG2, and human breast cancer, which had higher levels of activated PKCα, when compared to normal skin, liver, and human breast tissue lysates, respectively. Moreover, addition of Ro‐31‐7549, an inhibitor with great specificity for PKCα, to the phosphorylation reaction caused a dose‐dependent reduction in phosphorylation, but no inhibition was identified with the addition of rottlerin and H‐89. These results show that this peptide has great potential as a PKCα‐specific substrate.
Improvement of photovoltaic performances of organic thin‐film solar cells by fast electron mobility oxadiazole as an exciton blocking layer material
Authors: Ichikawa Musubu , Shimizu Chieko , Koyama Toshiki , Taniguchi Yoshio 
Published: April 2008

AbstractWe demonstrated improvements of photovoltaic performances of organic thin‐film solar cells using an oxadiazole compound (Bpy‐OXD) as an exciton blocking layer (EBL) material. Due to fast electron mobility of Bpy‐OXD of above 10–3 cm2/Vs, the photovoltaic cell with Bpy‐OXD showed higher performance than that with bathocuproine, a conventional EBL material. High amorphous nature of Bpy‐OXD with high glass transition temperature of 106 °C probably also caused a part of the improvements because of protecting photovoltaic layers from damaging during upper metal electrode deposition. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Transparent conductive Ta2O5‐codoped ITO thin films prepared by different heating process
Authors: Zhang B. , Dong X. P. , Xu X. F. , Wu J. S. 
Published: April 2008

AbstractTantalum‐doped indium tin oxide thin films were deposited by a cosputtering technique with an ITO target and a Ta2O5 target. The variations of microstructure, electrical and optical properties with substrate temperature and annealing temperature were investigated in some detail. Ta‐doped ITO thin films showed better crystalline structure with different prominent plane orientation by different heating process. ITO:Ta thin films deposited at room temperature showed better optical and electrical properties. Increasing substrate temperature and reasonable annealing temperature could remarkably improve the optical and electrical properties of the films. The variation of carrier concentration had an important influence on near‐IR reflection, near‐UV absorption and optical bandgap. ITO:Ta thin films showed wider optical bandgap. ITO:Ta thin films under the optimum parameters had a sheet resistance of 10–20 Ω/sq and a transmittance of 85% with an optical bandgap of above 4.0 eV. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Off‐diagonal magneto‐impedance in amorphous microwires with diameter 6–10 μm and application to linear magnetic sensors
Authors: Ipatov M. , Zhukova V. , Blanco J. M. , Gonzalez J. , Zhukov A. 
Published: April 2008

AbstractOff‐diagonal component of magneto‐impedance tensor with pulse excitation is very promising for high sensitivity magnetic field sensor applications. We report novel results on studies of off‐diagonal MI effect and magnetic properties in amorphous glass‐coated microwires with nearly‐zero and negative magnetostriction constant and metallic nucleus diameter ranging between 6 μm and 10 μm. Off‐diagonal impedance tensor ζφz (Hex) has been investigated in ultra‐thin amorphous glass‐coated microwires in as‐cast state and after Joule heating treatment. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Magnetostatic properties of Co‐rich amorphous microwires: theory and experiment
Authors: Aranda G. R. , Usov N. A. , Zhukova V. , Zhukov A. , Gonzalez J. 
Published: April 2008

AbstractThe calculations of the residual quenching stresses and magnetization curves of glass‐coated Co‐rich microwires are carried out to study their dependence on the material parameters characterizing the properties of metallic core and glass shell of the wire. It is shown that Co‐rich microwires with strictly negative magnetostriction must have small remanence and nearly linear dependence of wire magnetization in applied magnetic field. The measured hysteresis loops for a family of Co67Fe3.8Ni1.4Si14.5B11.6Mo1.7 microwires do demonstrate this behaviour. The reasons for the unusual behaviour of some Co‐rich microwires showing finite remanence are discussed in the paper. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Preparation of 3 inch freestanding GaN substrates by hydride vapor phase epitaxy with void‐assisted separation
Authors: Yoshida T. , Oshima Y. , Eri T. , Watanabe K. , Shibata M. , Mishima T. 
Published: April 2008

AbstractBy using the hydride vapor phase epitaxy and a void‐assisted separation method, freestanding 3 inch GaN substrates were successfully fabricated for the first time, and the process showed an excellent reproducibility. A thick GaN layer 3.2 inches in diameter was easily separated from the base substrate. No cracks were generated during the separation process, and the separation process was no more difficult than that of 2 inch GaN substrates. The dislocation density was of the order of 106 cm–2. The carrier density was approximately 1 × 1018 cm–3 and the mobility was 3.4 × 102 cm2 V–1 s–1. The concentrations of impurities, estimated by secondary‐ion mass spectrometry, were below the limit of detection, except for Si. The Si concentration was approximately 1 × 1018 cm–3, which is in good agreement with the carrier density. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
High‐efficiency GaN HEMTs on 3‐inch semi‐insulating SiC substrates
Authors: Waltereit P. , Bronner W. , Quay R. , Dammann M. , Müller S. , Kiefer R. , Raynor B. , Mikulla M. , Weimann G. 
Published: April 2008

AbstractWe report on device performance and reliability of our 3″ GaN high electron mobility transistor (HEMT) technology. AlGaN/GaN HEMT structures are grown on semi‐insulating SiC substrates by metal‐organic chemical vapor deposition (MOCVD) with sheet resistance uniformities better than 2%. Device fabrication is performed using standard processing techniques involving both e‐beam and stepper lithography. AlGaN/GaN HEMTs demonstrate excellent high‐voltage stability and large efficiencies. Devices with 0.5 µm gate length exhibit two‐terminal gate‐drain breakdown voltages in excess of 160 V and drain currents well below 1 mA/mm when biased at 80 V drain bias under pinch‐off conditions. Load‐pull measurements at 2 GHz return both a linear relationship between drain bias voltage and output power as well as power added efficiencies beyond 55% up to 72 V drain bias for which an output power density of 9 W/mm with 25 dB linear gain is obtained. Reliability tests indicate a promising device stability under both radio frequency (RF) and direct current (DC) stress conditions. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electro‐optical intersubband modulators at telecommunication wavelengths based on GaN/AlN quantum wells
Authors: Kheirodin N. , Nevou L. , Machhadani H. , Tchernycheva M. , Lupu A. , Julien F. H. , Crozat P. , Meignien L. , Warde E. , Vivien L. , Pozzovivo G. , Golka S. , Strasser G. , Guillot F. , Monroy E. , Remmele T. , Albrecht M. 
Published: April 2008

AbstractWe report the demonstration of intersubband modulators operating at telecommunication wavelengths at room temperature based on GaN/AlN quantum wells. We first investigate electro‐optical modulators making use of electron tunneling in coupled quantum wells. Electro‐absorption modulation with opposite sign induced by the electron tunneling between the reservoir and active quantum wells is observed at λ = 1.3–1.6 µm and λ = 2.2 µm. We show that by reducing the mesa size down to 15 × 15 µm2, optical modulation bandwidth as large as 3 GHz can be obtained. We then investigate waveguide intersubband modulators relying on the depletion of the ground electronic state of a 3 quantum well active region. Modulation depths as large as 14 dB in the wavelength range of 1.2–1.6 µm are obtained under –9 V/+7 V voltage swing. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of growth conditions on the conductivity of Mg doped p‐type GaN by Molecular Beam Epitaxy
Authors: Simon John , Jena Debdeep 
Published: April 2008

AbstractThe performance of III–V nitride heterostructure bipolar transistors has been limited by highly resistive p‐type layers, in addition to difficulties associated with a precise p–n junction placement at the emitter‐base heterojunction due to the Mg‐memory effect during growth by Metal‐Organic Chemical Vapor Deposition. The problem of precise p–n heterojunction placement can be solved by Molecular Beam Epitaxy growth. To investigate this possibility, in this work, we present a comprehensive study of the effect of III/V ratio, growth temperature, and Mg doping on the resistivity of Mg doped GaN layers grown by Molecular Beam Epitaxy. N2‐rich growth conditions are found to lead to a temperature‐ independent low hole mobility, as opposed to Ga‐rich growth conditions that lead to higher hole mobilities that vary with temperature. In addition, the growth temperature, Ga flux, and Mg flux windows leading to the highest p‐type conductivity are identified. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Origin of additional threading dislocations in AlGaN grown on GaN using AlN as an interlayer
Authors: Datta R. , McAleese C. , Cherns P. , Rayment F. D. G. , Humphreys C. J. 
Published: April 2008

AbstractThick AlGaN layers with high Al contents (50%) grown epitaxially on GaN crack due to tensile strain arising from the lattice parameter mismatch. AlN can be used to prevent this cracking but there is a concomitant increase in the edge‐type threading dislocations in the AlGaN film. In this contribution the origin of the additional threading dislocations (TDs) is investigated. The AlN interlayer itself micro‐cracks to relieve strain, and overgrowth of AlGaN on such a relaxed/cracked AlN layer gives rise to the generation of additional edge type TDs along the crack lines. This appears to be due to terminated misfit dislocation lines at the crack facets that are replicated during subsequent growth, resulting in additional edge TDs in the upper AlGaN layer. The contribution of cracks in generating additional edge TDs can also depend on whether the crack lines are filled or a void is created during AlGaN growth. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)