bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optically pumped lasing at 300.4 nm in AlGaN MQW structures grown by plasma‐assisted molecular beam epitaxy on c‐Al2O3
Authors: Jmerik V. N. , Mizerov A. M. , Shubina T. V. , Toropov A. A. , Belyaev K. G. , Sitnikova A. A. , Yagovkina M. A. , Kop'ev P. S. , Lutsenko E. V. , Danilchyk A. V. , Rzheutskii N. V. , Yablonskii G. P. , Monemar B. , Ivanov S. V. 
Published: May 2010

AbstractWe have demonstrated optically pumped room‐temperature pulse lasing at 300.4 nm from an AlGaN‐based multiple‐quantum‐well (MQW) structure grown by plasma‐assisted molecular beam epitaxy on a c‐sapphire substrate. The lasing was achieved at the threshold peak power of ∼12 MW/cm2. The MQW structure involved AlGaN/AlN short‐period superlattices to decrease the threading dislocation densities from 1011 down to 109–1010 cm−2. Studies of time‐resolved photoluminescence (TRPL) spectra and cw PL temperature dependences (10–300 K) of different MQW structures, as well as numerical calculations of the optical gain and confinement in the laser structure allowed us to conclude about the optimum design of AlGaN‐based MQW structures for the lower threshold UV lasing.
AlInN HEMT grown on SiC by metalorganic vapor phase epitaxy for millimeter‐wave applications
Authors: Guo Shiping , Gao Xiang , Gorka Daniel , Chung Jinwoork W. , Wang Han , Palacios Tomas , Crespo Antonio , Gillespie James K. , Chabak Kelson , Trejo Manuel , Miller Virginia , Bellot Mark , Via Glen , Kossler Mauricio , Smith Howard , Tomich David 
Published: May 2010

AbstractIn this work we present the epitaxial and device results of AlInN/GaN HEMTs grown on SiC by metalorganic vapor phase epitaxy. High quality AlInN/GaN HEMT structures with sub‐10 nm AlInN barrier were grown with very low Ga background level (<1%). The low Rsh of 215 Ω/sq was obtained with an excellent standard deviation of 1.1% across 3″ wafers. Lehighton RT contactless Hall tests show a high mobility of 1617 cm2/V s and sheet charge density of 1.76 × 1013/cm2. DC characteristics of an AlInN/GaN HEMT with a gate length of 0.1 µm and 25 nm Al2O3 passivation show maximum drain current (IDS,max) of 2.36 A/mm at VGS = 2 V. Gate recessed devices with 0.15 µm gate length and 25 nm Al2O3 passivation resulted in maximum transconductance (gm) of 675 mS/mm, the highest value ever reported in AlInN transistors. Excellent frequency response was obtained. The maximum fT is 86 GHz and fmax is 91.7 GHz.
GaInN‐based LED structures on selectively grown semi‐polar crystal facets
Authors: Scholz Ferdinand , Wunderer Thomas , Feneberg Martin , Thonke Klaus , Chuvilin Andrei , Kaiser Ute , Metzner Sebastian , Bertram Frank , Christen Jürgen 
Published: May 2010

AbstractIn conventional nitride‐based light emitting diodes, huge internal electric fields lead to a reduced overlap of electron and hole wave functions in the active GaInN quantum wells as a consequence of the piezoelectricity of these polar materials. In order to minimize these internal fields while still maintaining the well‐established c‐direction as main epitaxial growth direction for high‐quality low‐defect‐density layers, we have investigated semi‐polar LED structures on the side‐facets of triangular GaN stripes grown by selective area epitaxy. The reduced internal electric field could be confirmed by several spectroscopic methods. We found a strongly facet dependent growth mechanism leading to very flat surfaces on $\{ 1\bar {1}01\}$ facets as opposed to their $\{ 11\bar {2}2\}$ counterparts. An increased indium uptake on semipolar $\{ 1\bar {1}01\}$ facets as compared to conventional c‐plane layers helped to shift the LED emission to longer wave lengths beyond 500 nm in the green spectral range despite the significantly reduced field‐dependent Stark shift.
Impedance measurement for microstructure characterization and internal surface estimation of macroporous silicon
Authors: RoyChaudhuri C. , Jana M. , Bandopadhyay N. R. 
Published: May 2010

AbstractIn this paper, a simple and convenient method based on impedance measurement has been proposed for the first time to evaluate the average porosity, pore radius, and internal surface area of macroporous silicon structure fabricated by electrochemical method. The porosity and the average pore radius have been obtained by developing a geometrical model and applying the generalized effective medium approximation theory to the dc and ac impedance measurement of both unoxidized and thermally oxidized macroporous silicon. The internal surface area per unit volume is then computed from the porosity and the pore radius using the same model. The method has been applied to a wide range of porosity from 30 to 58% fabricated on p‐type <100> silicon with a resistivity of 10–20 Ω cm. Experimental verification of porosity, mean pore radius, and internal surface area have been performed by standard gravimetric technique and by top‐view and cross‐section SEM imaging, respectively. A typical mean pore radius, porosity, and internal surface area of a macroporous silicon sample has been obtained to be 1.52 µm, 54.2%, and 3565.7 cm2/cm3, respectively, from the impedance measurement and 1.5 µm, 55%, and 3666.7 cm2/cm3 from SEM and gravimetric analysis which shows that the results are within 2% of the values obtained by conventional methods. The advantages of this method over the other recently reported techniques for similar characterization have been discussed.
Synthesis and physical properties of cylindrite micro tubes and lamellae
Authors: Kaden Ronny , Wagner Gerald , Sturm Chris , Schmidt‐Grund Rüdiger , von Wenckstern Holger , Prager Andrea , Bente Klaus , Grundmann Marius 
Published: May 2010

AbstractThe natural semiconductor cylindrite FeSn4Pb3Sb2S14 was synthesised by chemical vapour transport (CVT). Crystals with lamellar shape and cylindrical morphology could be deposited on substrates. The endothermic reactions responsible for material transport were simulated by means of thermodynamic modelling. Cylindrite belongs to the class of misfit layered compounds, where its modulated incommensurate crystal structure is based on the regular alternation of two types of layers. The so called T‐ and H‐slab are incommensurately linked. Determined from single crystal XRD measurements, the modulation of atom positions as well as modulation of metal site occupancy of both subsystems are presented. The origin of super structure reflections found in scattering experiments can be clearly explained by a structure model. Based on experimentally determined single crystal XRD data and HRTEM inspections a model is derived to explain the formation of cylindrical architecture of crystals. The specific electrical conductivity of cylindrite improves from 10−2 to 101 Ω−1/m when increasing the atomic ratio Pb/Sb from 1.35 to 1.75. In the same way the Seebeck coefficient S can reach negative values of −730 µV/K indicating n‐type conduction. The band gap energy Eg rises from 0.65 to 1.15 eV with decreasing (Pb + Fe)/(Sn + Sb) from 0.71 to 0.53. magnified image
TEM bright field image of high magnification demonstrating the continuous bending of (100) layers in a cylindrite cylinder.
Ionized physical vapor deposited Al2O3films: Does subplantation favor formation of α‐Al2O3?
Authors: Sarakinos K. , Music D. , Nahif F. , Jiang K. , Braun A. , Zilkens C. , Schneider J. M. 
Published: May 2010

AbstractThe broad energy distributions of the condensing particles typically encountered in ion assisted vapor deposition techniques are often a drawback when attempting to understand the effect of the energetic bombardment on the film properties. In the current study, a monoenergetic Al+beam generated by a filtered cathodic arc discharge is employed for the deposition of alumina (Al2O3) films at well defined Al+ion energies between 4 eV and 200 eV at a substrate temperature of 720 °C. Structural analysis shows that Al+energies of 40 eV or larger favor the formation of the thermodynamically stable α‐Al2O3phase at the expense of other metastable Al2O3polymorphs. The well defined ion energies are used as input for Monte‐Carlo based simulations of the ion–surface interactions. The results of these simulations reveal that the increase of the Al+ion energy leads to an increase in the fraction of ions subplanted into the growing film. These findings underline the previously not considered role of subsurface processes on the phase formation of ionized physical vapor deposited Al2O3films. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Amelioration of oxidative stress by dandelion extract through CYP2E1 suppression against acute liver injury induced by carbon tetrachloride in sprague‐dawley rats
Authors: Park Chung Mu , Cha Yeon Suk , Youn Hyun Joo , Cho Chung Won , Song Young Sun 
Published: May 2010

AbstractThe protective effects of common dandelion leaf water extract (DLWE) were investigated by carbon tetrachloride (CCl4) induced hepatitis in Sprague‐Dawley rats. The animals were divided into five groups: normal control, DLWE control, CCl4 control, and two DLWE groups (0.5 and 2 g/kg bw). After 1 week of administering corresponding vehicle or DLWE, a single dose of CCl4 (50% CCl4/olive oil; 0.5 mL/kg bw) was administered 24 h before killing in order to produce acute liver injury. The DLWE treatment significantly decreased CCl4‐induced hepatic enzyme activities (AST, ALT and LDH) in a dose dependent manner. Also, the obstructed release of TG and cholesterol into the serum was repaired by DLWE administration. Hepatic lipid peroxidation was elevated while the GSH content and antioxidative enzyme activities were reduced in the liver as a result of CCl4 administration, which were counteracted by DLWE administration. Furthermore, the hepatocytotoxic effects of CCl4 were confirmed by significantly elevated Fas and TNF‐? mRNA expression levels, but DLWE down‐regulated these expressions to the levels of the normal control. Highly up‐regulated cytochrome P450 2E1 was also lowered significantly in the DLWE groups. These results indicate that DLWE has a protective effect against CCl4‐induced hepatic damage with at least part of its effect being attributable to the attenuation of oxidative stress and inflammatory processes resulting from cytochrome P450 activation by CCl4. Copyright © 2010 John Wiley & Sons, Ltd.
Effect of isolated fractions ofHarpagophytum procumbensD.C. (devil's claw) on COX‐1, COX‐2 activity and nitric oxide production on whole‐blood assay
Authors: Anauate Maria Cecilia , Torres Luce Maria , de Mello Suzana Beatriz Veríssimo 
Published: May 2010

AbstractThe present study evaluates the effect of isolated fractions ofHarpagophytum procumbens(devil's claw) on cyclooxygenase (COX‐1 and COX‐2) activities and NO production using a whole blood assay. The activity of COX‐1 was quantified as platelet thromboxane B2production in blood clotting and COX‐2 as prostaglandin E2production in LPS‐stimulated whole blood. Total NO2−/NO3−concentration was determined by Griess reaction in LPS stimulated blood. Assays were performed by incubation of isolated fractions obtained by flash chromatography monitored with HPLC, TLC and identified by1HNMR, containing different amounts of harpagoside with blood from healthy donors. Indomethacin and etoricoxib were the positive controls of COX‐1 and COX‐2 Inhibition. Data shows that fraction containing the highest concentration of harpagoside inhibited indistinctively COX‐1 and COX‐2 (37.2 and 29.5% respectively) activity and greatly inhibited NO production (66%). In contrast the fraction including iridoid pool increased COX‐2 and did not alter NO and COX‐1 activities. The fraction containing cinnamic acid was able to reduce only NO production (67%). Our results demonstrated that the harpagoside fraction is the main responsible for the effect of devils claw on these enzyme activities. However, other components from devil's claw crude extract could antagonize or increase the synthesis of inflammatory mediators. Copyright © 2010 John Wiley & Sons, Ltd.
Individual and combined effects of foods on helicobacter pylori growth
Authors: Keenan Jacqueline I. , Salm Nina , Hampton Mark B. , Wallace Alison J. 
Published: May 2010

AbstractEradication of H. pylori can reduce the risk of non‐cardia gastric cancer developing in infected humans. Thus, the consumption of foods that inhibit the growth of these bacteria may provide an alternative to current therapies that include antibiotics, proton pump inhibitors and/or bismuth salts. This study describes a simple broth dilution assay developed to screen a range of foods for their individual and combined effects on H. pylori growth. It was found that foods with measurable anti‐H. pylori activity have an effect greater in combination than the sum of foods tested singly, and that this was most noticeable with a combination of broccoli sprouts and blackcurrant oil. The results suggest that food synergy should be considered in any nutraceutical approach to H. pylori infection. Copyright © 2010 John Wiley & Sons, Ltd.
Xanthone constituents of the fruits of garcinia mangostana with anticomplement activity
Authors: Quan Gui‐Hua , Oh Sei‐Ryang , Kim Jung‐Hee , Lee Hyeong‐Kyu , Kinghorn A. Douglas , Chin Young‐Won 
Published: May 2010

AbstractPhytochemical investigation of a chloroform‐soluble fraction of the freeze‐dried fruits of Garcinia mangostana (Clusiaceace) with anticomplement activity in the classical pathway led to the identification of five known xanthones. The structures of these compounds were confirmed by interpretation of NMR and MS spectroscopic data. Of the isolates obtained, 1‐isomangostin and garcinone E were found to be active constituents in the anticomplement assay used. Copyright © 2010 John Wiley & Sons, Ltd.
Stainless steel bottles for extra virgin olive oil packaging: effects on shelf‐life
Authors: Parenti Alessandro , Masella Piernicola , Spugnoli Paolo , Mazzanti Laura , Migliorini Marzia 
Published: May 2010

AbstractThe quality changes in extra virgin olive oil afforded by the conservation in bottles of different materials were assessed in a 12‐month shelf‐life test. Transparent clear glass (TCG), green coloured glass (CG) and stainless steel (SS) 250‐ml bottles were studied (in triplicates) alternating natural and fluorescent light to simulate the ‘in the drugstore’ conditions. Every 2 months, the quality decay was assessed by monitoring some chemicals parameters and by sensory evaluation. Principal component analysis evidenced a clustering of the samples as a function of storage time and bottle type. The SS bottles showed the best storage performances, whereas only minor differences were detected in TCG and CG. A large variability was detected within the replicated glass bottles, probably as a consequence of some uncontrolled variations in the light exposure. This was confirmed by the measure of light intensity over the storing surface, which showed a large variability (15%) around an average value of 380 lux. Under light exposure, a limited antioxidant effect of phenolic compounds was recorded. Only some specific phenols seem to play an important role in oil protection against oxidation. Copyright © 2010 John Wiley & Sons, Ltd.
Microbiological, colour and sensory properties of fresh beef steaks in low carbon monoxide concentration
Authors: Venturini Anna Cecilia , Contreras‐Castillo Carmen J. , Faria José de Assis Fonseca , Gallo Cláudio Rosa , Silva Tâmara Zago , Shirahigue Ligianne Din 
Published: May 2010

AbstractSteaks from gluteus medius m. (GM) and longissimus dorsi m. (LD) were packaged in atmospheres containing two low levels of CO (0.2 and 0.4%) in combination with 21% O2 or without oxygen. The other components of the modified atmosphere packaging systems were carbon dioxide (30%) and nitrogen (balance). Steaks were evaluated on 0, 7, 14 and 21 days of storage at about 2oC to investigate the effects of the gas mixtures on the microflora, instrumental (CIE L*a*b*) and visual colour and odour. The preservation of colour and odour of GM and LD steaks packaged under low carbon monoxide was best achieved using anoxic mixtures containing 0.2% CO and 30% CO2. Steaks packaged without oxygen retained a desirable colour and practically did not present a visible discoloration or perceptive off‐odour along the entire storage time. Colour stabilization with 0.2% CO and 30% CO2, without O2, following storage up to 21 days at 2°C did not increase microbial risk of products. The increase in CO from 0.2 to 0.4% had a negative effect on the colour of LD steaks which was regarded as ‘artificial’ by some panellists. The higher stability achieved in this study using 0.2% CO may result from increased stability of the colour from Bos indicus × Bos Taurus cross. Discoloration and off‐odour were evident in the GM and LD steaks packaged aerobically after 14 days of storage when the counts of deteriorant bacteria achieved approximately 6.5 to 9.7 log CFU/g. Highest bacteriostatic effect could be obtained if the volume of injected CO2 was sufficient to saturate the meat and keep in balance around the product during storage. Copyright © 2010 John Wiley & Sons, Ltd.
Monitoring chloramines and bromamines in a humid environment using selected ion flow tube mass spectrometry
Authors: Hu Wan‐Ping , Langford Vaughan S. , McEwan Murray J. , Milligan Daniel B. , Storer Malina K. , Dummer Jack , Epton Michael J. 
Published: May 2010

AbstractThe selectivity and sensitivity of selected ion flow tube mass spectrometry (SIFT‐MS) for individual breath analysis of haloamines has been improved by heating the flow tube in a commercial instrument to around 106°C. Data is presented showing the marked reduction in the number density of water clusters of product ions of common breath metabolites that are isobaric with the product ions from monochloramine and monobromamine that are used to monitor the haloamine concentrations. These results have direct relevance to the real‐time monitoring of chloramines in drinking water, swimming pools and food processing plants. However, once the isobaric overlaps from water cluster ions are reduced at the higher temperatures, there is no conclusive evidence showing the presence of haloamines on single breath exhalations in the mid parts per trillion range from examination of the breaths of volunteers. Copyright © 2010 John Wiley & Sons, Ltd.
Strong anion‐exchange liquid chromatography coupled with isotope ratio mass spectrometry using a Liquiface interface
Authors: Morrison Douglas J. , Taylor Karen , Preston Tom 
Published: May 2010

AbstractThe introduction of liquid chromatography coupled with isotope ratio mass spectrometry (LC/IRMS) as an analytical tool for the measurement of isotope ratios in non‐volatile analytes has somewhat simplified the analytical cycle from sample collection to analysis mainly due to the avoidance of the extensive sample processing and derivatisation that were necessary for gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS). Here we test the performance of coupling strong anion exchange to IRMS using only the second commercially available interface; the Liquiface.The system was modified from installation specification to improve peak resolution in the interface and maintain peak separation from the column to the mass spectrometer. The system performance was assessed by the determination of sensitivity, accuracy and precision attained from carbohydrate separations. The system performed satisfactorily after modifications, resulting in maintenance of peak resolution from column to mass spectrometer. The sensitivity achieved suggested that ∼150 ng carbon could be analysed with acceptable precision (<0.3‰). Accuracy was maintained in the interface as determined by correlation with offline techniques, resulting in regression coefficient of r2 = 0.98 and a slope of 0.99. The average precision achieved for the separation of seven monosaccharides was 0.36‰. The integration of a carbonate removal device limited the effect of background carbon perturbations in the mass spectrometer associated with eluent gradients, and the coupling of strong anion‐exchange chromatography with IRMS was successfully achieved using the Liquiface. Copyright © 2010 John Wiley & Sons, Ltd.
Application of selected ion flow tube mass spectrometry to real‐time atmospheric monitoring
Authors: Prince Barry J. , Milligan Daniel B. , McEwan Murray J. 
Published: May 2010

AbstractData are presented for real‐time atmospheric monitoring of volatile organic chemicals (VOCs) in air using selected ion flow tube mass spectrometry (SIFT‐MS) technology. These measurements were made by one of the new generation of SIFT‐MS instruments. Results are shown for five VOCs that were continually monitored from a stationary sampling point over a 4‐day period: ethene, ethanol, 1,3‐butadiene, benzene and toluene. All analytes except ethene in the study have at least two simultaneous and independent measures of concentration. These results demonstrate the great advances in SIFT‐MS that have been made in recent years. 1,3‐Butadiene is measured at a concentration of 9 pptv with a precision of 44%. For a 1‐s integration time, a detection limit of 50 pptv is achieved. Instrument sensitivities are reported for all five analytes. Copyright © 2010 John Wiley & Sons, Ltd.
An efficient parallelization of phosphorylated peptide and protein identification
Authors: Wang Leheng , Wang Wenping , Chi Hao , Wu Yanjie , Li You , Fu Yan , Zhou Chen , Sun Ruixiang , Wang Haipeng , Liu Chao , Yuan Zuofei , Xiu Liyun , He Si‐Min 
Published: May 2010

AbstractProtein sequence database search based on tandem mass spectrometry is an essential method for protein identification. As the computational demand increases, parallel computing has become an important technique for accelerating proteomics data analysis. In this paper, we discuss several factors which could affect the runtime of the pFind search engine and build an estimation model. Based on this model, effective on‐line and off‐line scheduling methods were developed. An experiment on the public dataset from PhosphoPep consisting of 100 RAW files of phosphopeptides shows that the speedup on 100 processors is 83.7. The parallel version can complete the identification task within 9 min, while a stand‐alone process on a single PC takes more than 10 h. On another larger dataset consisting of 1 366 471 spectra, the speedup on 320 processors is 258.9 and the efficiency is 80.9%. Our approach can be applied to other similar search engines. Copyright © 2010 John Wiley & Sons, Ltd.
Behavioral profiles—a way to model and validate program behavior
Authors: Koskinen Johannes , Kettunen Markus , Systä Tarja 
Published: May 2010

AbstractSoftware architecture contains, in addition to its structural part, interaction patterns that can be regarded as part of the architectural solution of the system. The interaction patterns define architecturally significant behavior of the software system. In this paper we propose a visual modeling language, behavioral profiles, for specifying architecturally significant behavioral rules for an application. The language is built on the Unified Modeling Language (UML), which is a visual language widely used in software development. We show how behavioral profiles can be used to support software designers in creating behavioral models that conform to some predefined rules and for ensuring that an application behaves correctly with respect to the rules given in the profiles. A tool called Bebop was built to support software engineers in behavioral profile‐based design and analysis of program behavior. To evaluate the approach and the tools in different application domains, they are utilized in three cases. The size of the applications used in the cases varies from small to quite large software systems, and from academic to industrial ones. The examples demonstrate how the approach presented can be used in practice for different steps in a software engineering process. The examples cover specializing an application framework and monitoring the program execution in run‐time. In addition, they show how behavioral profiles can be used to support guided program comprehension and to validate program execution by analyzing execution traces. Copyright © 2010 John Wiley & Sons, Ltd.