bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evolution of the Transrotational Structure During Crystallization of Amorphous Ge2Sb2Te5 Thin Films
Authors: Rimini Emanuele , De Bastiani Riccardo , Carria Egidio , Grimaldi Maria Grazia , Nicotra Giuseppe , Bongiorno Corrado , Spinella Corrado 
Published: June 2009

AbstractThe crystallization of amorphous Ge2Sb2Te5 thin films has been studied by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The analysis has been performed on partially crystallized films, with a surface crystalline fraction (fS) ranging from 20% to 100%. XRD analysis indicates the presence, in the partially transformed layer, of grains with average lattice parameters higher than that of the equilibrium metastable cubic phase (from 6.06 Å at fS=20% to 6.01 Å at fS=100%). The amorphous to crystal transition, as shown by TEM analysis, occurs through the nucleation of face-centered-cubic crystal domains at the film surface. Local dimples appear in the crystallized areas, due to the higher atomic density of the crystal phase compared to the amorphous one. At the initial stage of the transformation, a fast bi-dimensional growth of such crystalline nucleus occurs by the generation of transrotational grains in which the lattice bending gives rise to an average lattice parameter significantly larger than that of the face-centered-cubic phase in good agreement with the XRD data. As the crystallized fraction increases above 80%, dimples and transrotational structures start to disappear and the lattice parameter approaches the bulk value.
Study of Mo selenisation process on different Mo substrates
Authors: Kaupmees Liina , Altosaar Mare , Volobujeva Olga , Barvinschi Paul 
Published: June 2009

AbstractIn the present work we studied the influence of selenisation temperature, Se vapour pressure and duration of the process on the properties of MoSe2 layer formed on Mo-foil and on sputtered Mo layers on soda lime and Mo-on-ITO glasses. We found that MoSe2 layer thickness (dL) on Mo-foil depended linearly on selenisation time. The thickness of MoSe2 layer on Mo-foil (dL) depended on Se vapour pressure as a function , where n ≈ 0.5. The same dependence was also found for sputtered Mo layers in low Se vapour pressure region of 13 – 133 Pa. MoSe2 layer thickness depended on the origin of Mo layer which is related with the density of Mo layer: MoSe2 on Mo foil was thicker than on sputtered Mo. All the MoSe2 layers were full of cracks if Se vapour pressure was higher than 1333 Pa. All tested MoSe2 layers showed p-type conductivity.
Transport Properties of Thermoelectric Nanocomposites
Authors: Woods Lilia M , Popescu Adian , Martin Joshua , Nolas George S. 
Published: June 2009

AbstractWe present a theoretical model for carrier conductivity and Seebeck coefficient of thermoelectric materials composed of nanogranular regions. The model is used to successfully describe experimental data for chalcogenide PbTe nanocomposites. We also present similar calculations for skutterudite CoSb3 nanocomposites. The carrier scattering mechanism is considered explicitly and it is determined that it is a key factor in the thermoelectric transport process. The grain interfaces are described as potential barriers. We investigate theoretically the role of the barrier heights, widths, and distances between the barriers to obtain an optimum regime for the composites thermoelectric characetristics.
Ternary Copper-Based Diamond-Like Semiconductors for Thermoelectric Applications
Authors: Morelli Donald T , Skoug Eric J. 
Published: June 2009

AbstractThermoelectric materials can provide sources of clean energy and increase the efficiency of existing processes. Solar energy, waste heat recovery, and climate control are examples of applications that could benefit from the direct conversion between thermal and electrical energy provided by a thermoelectric device. The widespread use of thermoelectric devices has been prevented by their lack of efficiency, and thus the search for high-efficiency thermoelectric materials is ongoing. Here we describe our initial efforts studying copper-containing ternary compounds for use as high-efficiency thermoelectric materials that could provide low-cost alternatives to their silver-containing counterparts. The compounds of interest are semiconductors that crystallize in structures that are variants of binary zincblende structure compounds. Two examples are the compounds Cu2SnSe3 and Cu3SbSe4, for which we present here preliminary thermoelectric characterization data.
Investigation of MgAlON Films on Electron Emission Properties
Authors: Nishitani Mikihiko , Sakai Masahiro , Terauchi Masaharu , Morita Yukihiro , Yamauchi Yasushi 
Published: June 2009

AbstractThe film of MgO-AlN system was manufactured by the conventional magnetron sputtering process. It is observed that a Fermi level could be raised by letting AlN composition increase, confirmed by ultraviolet (UV) photon energy dependence of the electronic emission, and investigated with XPS that the surface reaction, such as surface hydroxide / carbonate of MgO, could be controlled in addition of AlN. The glow discharge characteristics for MgAlON films were evaluated from the minimum pressure that a glow discharge is started under constant RF power, which correspond to the result of the analysis for the secondary electron emission coefficient, using Metastable De-excitation Spectroscopy (MDS).
Optimizing the Screen-Grid Field Effect Transistor for high drive current and low Miller capacitance
Authors: Shadrokh Yasaman , Fobelets Kristel , Velazquez-Perez Enrique 
Published: June 2009

AbstractReduction of parasitic capacitances and improvement of the on-off current ratio (ION/IOFF) can be achieved by increasing the gate control in Field Effect Transistors (FETs). Multiple gated FETs (MugFETs) lend themselves well for this. The MugFET investigated in this manuscript is the Screen Grid FET (SGrFET) that consists of multiple gate cylinders inside the channel perpendicular to the current flow. In this work we illustrate, using 2D Technology Computer Aided Design (TCAD), that the multiple geometrical degrees of freedom of the SGrFET can be exploited to simultaneously optimise the on-current, ION and the gate-drain Miller parasitic capacitance for increased switching speed.
Measuring Local Mechanical Properties using FIB Machined Cantilevers
Authors: Armstrong David Edward John , Wilkinson Angus Jonathan , Roberts Steve George 
Published: June 2009

AbstractMicro-scale Focused Ion Beam (FIB) machined cantilevers were manufactured in single crystal copper, polycrystalline copper and a copper-bismuth alloy. These were imaged and tested in bending using a nanoindenter. Cantilevers machined inside a single grain of polycrystalline copper were tested to determine their (anisotropic) Young's modulus: results were in good agreement with values calculated from literature values for single crystal elastic constants. The size dependence of yield behavior in the Cu microcantilevers was also investigated. As the thickness of the specimen was reduced from 23μm to 1.7μm the yield stress increased from 300MPa to 900MPa. Microcantilevers in Cu-0.02%Bi were manufactured containing a single grain boundary of known character, with a FIB-machined sharp notch on the grain boundary. The cantilevers were loaded to fracture allowing the fracture toughness of grain boundaries of different misorientations to be determined.
Bio-based Polyurethane-clay Nanocomposite Foams: Systheses and Properties
Authors: Liu Min , Petrovic Zoran S. , Xu Yijin 
Published: June 2009

AbstractStarting from a bio-based polyol through modification of soybean oil, BIOH™ X-210, two series of bio-based polyurethanes-clay nanocomposite foams have been prepared. The effects of organically-modified clay types and loadings on foam morphology, cell structure, and the mechanical and thermal properties of these bio-based polyurethanes-clay nanocomposite foams have been studied with optical microscopy, compression test, thermal conductivity, DMA and TGA characterization. Density of nanocomposite foams decreases with the increase of clay loadings, while reduced 10% compressive stress and yield stress keep constant up to 2.5% clay loading in polyol. The friability of rigid polyurethane-clay nanocomposite foams is high than that of foam without clay, and the friability for nanofoams from Cloisite® 10A is higher than that from 30B at the same clay loadings. The incorporation of clay nanoplatelets decreases the cell size in nanocomposite foams, meanwhile increases the cell density; which would be helpful in terms of improving thermal insulation properties. All the nanocomposite foams were characterized by increased closed cell content compared with the control foam from X-210 without clay, suggesting the potential to improve thermal insulation of rigid polyurethane foams by utilizing organically modified clay. Incorporation of clay into rigid polyurethane foams results in the increase in glass transition temperature: the Tg increased from 186 to 197 to 204 °C when 30B concentration in X-210 increased from 0 to 0.5 to 2.5%, respectively. Even though the thermal conductivity of nanocomposite foams from 30B is lower than or equal to that of rigid polyurethane control foam from X-210, thermal conductivity of nanocomposite foams from 10A is higher than that of control at all 10A concentrations. The reason for this abnormal phenomenon is not clear at this moment; investigation on this is on progress.
Sound Absorption Characteristics of Porous Steel Manufactured by Lost Carbonate Sintering
Authors: Lu Miao , Hopkins Carl , Zhao Yuyuan , Seiffert Gary 
Published: June 2009

AbstractThis paper investigates the sound absorption characteristics of porous steel samples manufactured by Lost Carbonate Sintering. Measurements of the normal incidence sound absorption coefficient were made using an impedance tube for single-layer porous steel discs and assemblies comprising four layers of porous steel discs. The sound absorption coefficient was found not to vary significantly with pore size in the range of 250-1500 μm. In general, the absorption coefficient increases with increasing frequency and increasing thickness, and peaks at specific frequencies depending on the porosity. An increase in porosity tends to increase the frequency at which the sound absorption coefficient reaches this peak. An advantage was found in using an assembly of samples with gradient porosities of 75%-70%-65%-60% as it gave higher and more uniform sound absorption coefficients than an assembly with porosities of 75%.
Tetherless, 3D, Micro-Nanoscale Tools and Devices for Lab on a Chip Applications
Authors: Gracias David H 
Published: June 2009

AbstractOn the macroscale, a laboratory scientist uses a large number of tools such as flasks, crucibles, spatulas, filter funnels, test tube holders and grippers. If laboratory procedures are to be miniaturized within chips, micro and nanoscale analogs of these macroscopic tools could provide enhanced functionality. In this paper, I describe research efforts in our group aimed at engineering three dimensional, tetherless and lithographically patterned miniaturized structures for lab on a chip applications.
Subsurface Structures and Hydrogeologic Aquifers at the Western Side of Lake Nasser, Southwestern Desert, Egypt
Authors: Rabeh Taha , Bedair Said , Miranda Miguel , Carvalho João , Khalil Ahmed 
Published: June 2009

This work deals with the detection of water aquifers and the delineation of subsurface structures predominant in the basement rocks, and their relationship with these aquifers, at west Lake Nasser, southwestern desert, Egypt. An integrated study using geoelectric, geomagnetic, and well logging methods was conducted. Geoelectric surveys were initially performed to obtain vertical electrical sounding (VES) profiles to identify the subsurface geoelectric layers predominant in the area. This was followed by land magnetic surveys using a proton precession magnetometer in a mesh-like network covering the area of investigation. These surveys allowed us to determine the depth to basement rock, and establish the subsurface structures and their relation with the detected aquifers. To confirm the results, more than 20 boreholes were drilled and logged within the study area to determine the distribution of the subsurface water reservoirs and geological sequences in the area. The results indicate that the depth to the main water aquifer, represented by saturated Nubian sandstone, ranges from [Formula: see text]. The thickness of this reservoir varies from [Formula: see text]. The Nubian sandstone formation consists of three members (layers) that unconformably overlie the basement rocks. The depth to the basement rocks ranges from [Formula: see text]. The structure trend analyses indicate that the dominant tectonic trends are NW, NE, and Aqaba trends. These structures play an important role in the water supply from Lake Nasser and recharging the main water aquifer.
Geometric Alignment of 2D Gel Electrophoresis Images
Authors: Winz M.-L. , Rohr K. , Wörz S. 
Published: June 2009

Summary
Objectives: 2D gel electrophoresis (2-DE) is the method of choice for analyzing protein expression in the field of proteomics, for example, comparing a reference with a test population. However, due to complex physical and chemical processes the locations of proteins generally vary in different 2-DE images. To cope with these variations, accurate geometric alignment of 2-DE images is important.
Methods: We introduce a new elastic registration approach for 2-DE images, which is based on an analytic solution of the Navier equation using Gaussian elastic body splines (GEBS). With this approach cross-effects in elastic deformations can be handled, which is important for the registration of 2-DE images. In addition, landmark correspondences can be included to aid the registration in regions which are difficult to register using intensity information alone.
Results: We have successfully applied our approach to register 2-DE gel images of different levels of complexity. In each case, gel images from a reference group are compared with a test group. To analyze the performance of our approach, we have carried out a quantitative evaluation of the registration results. Moreover, we have performed an experimental comparison with a previous elastic registration scheme.
Conclusions: From the results we found that our approach is well-suited for the registration of 2-DE gel images of different levels of complexity and it turned out that the approach is superior to a previous hybrid scheme. Moreover, our approach is well-suited in a fully automatic setting and the performance can further be improved when landmark correspondences are available.
Gerichtete Evolution und rationales Design. Maßgeschneiderte Enzyme
Authors: Kourist Robert , Höhne Matthias , Bornscheuer Uwe 
Published: June 2009

AbstractImmer aktiver, stabiler und selektiver – so wünschen sich Chemiker und Industrie ihre Biokatalysatoren. Obwohl Enzyme ihre Rolle in der Natur meist perfekt spielen, entsprechen sie oft nicht den Anforderungen für industrielle Anwendungen. Nach dem Motto “was nicht passt, wird passend gemacht”, sind Biotechnologen in der Lage, Enzyme durch Veränderung ihrer minosäuresequenz zu optimieren. Die beiden grundsätzlich verschiedenen Konzepte rationales Design und gerichtete Evolution werden in diesem Artikel vorgestellt und aufgezeigt, wie damit Enzyme im Hinblick auf ihre Stabilität und Enantioselektivität verbessert werden können – bis hin zur Schaffung von Biokatalysatoren mit neuen, nicht‐natürlichen Aktivitäten.
Characterization of New PPARγ Agonists: Benzimidazole Derivatives – the Importance of Position 2
Authors: Goebel Matthias , Staels Bart , Unger Thomas , Kintscher Ulrich , Gust Ronald 
Published: June 2009

AbstractProbing SAR: The 1‐(biphenyl‐4‐ylmethyl)‐1H‐benzo[d]imidazole moiety is known to be an essential structural component of telmisartan for PPARγ activation. This study focused on the substituents at position 2 of the benzimidazole in an attempt to optimize PPARγ activation. In particular, the elongation of the alkyl chain and the introduction of an aromatic ring system were studied (shown).magnified imageThe relevance of substituents at C‐2 of the central benzimidazole of telmisartan for PPARγ activation has recently been demonstrated, and the most active compound identified in our previous work, 4′‐[(2‐propyl‐1H‐benzo[d]imidazol‐1‐yl)methyl]biphenyl‐2‐carboxylic acid (4 a), is used as lead structure in the present study. Modifications at C‐2 included butyl (4 b), iso‐butyl (4 c), tert‐butyl (4 d), phenyl (4 e), benzyl (4 f), phenethyl (4 g), 4‐chlorobenzyl (4 h), 4‐methoxyphenyl (4 i), and 4‐hydroxyphenyl (4 j) moieties. The compounds were tested in a differentiation assay using 3T3‐L1 preadipocytes and a luciferase assay with COS‐7 cells, transiently transfected with pGal4‐hPPARγDEF, pGal5‐TK‐pGL3 and pRL‐CMV, as established models for the assessment of cellular PPARγ activation. The activity in the luciferase assay increased in the alkyl series: propyl (4 a) <iso‐butyl (4 c) ≤ tert‐butyl (4 d) <butyl (4 b). A phenyl group at C‐2 led to the most active compound (4 e) in this study with an EC50 value of 0.27 μM. 4‐Hydroxylation of the C‐2 phenyl group (4 j) drastically decreased the activity (EC50=5.8 μm) presumably due to hydrophilic repulsion. This assumption was verified by O‐methylation to give compound 4 i, which maintained activity (EC50=0.29 μM). The weak effect of the benzyl derivative 4 f (EC50=1.4 μM) was abolished by an additional hydrophobic 4‐chloro substituent (4 h; EC50=0.55 μM) or an elongation of the alkyl chain between the phenyl and the benzimidazole core (4 g; EC50=0.31 μM).
Intramolecular Hydro‐N‐alkylation of Hydrazones and Oxime Ethers: Synthesis of Novel D‐Secoestrone Isoquinuclidines via Domino 1,5‐Hydride Shift/Cyclization
Authors: Frank Éva , Schneider Gyula , Kádár Zalán , Wölfling János 
Published: June 2009

AbstractThe direct transformation of a benzylic C(sp3)–H bond into a C–N bond from steroidal hydrazones 10b, 10f–l and oxime ethers 28b–d under the action of a stoichiometric amount of Lewis acid is reported. The mechanism of functionalization to give novel types of isoquinuclidine derivatives 25b, 25f–l and 32b–d is assumed to involve an intramolecular domino 1,5‐hydride transfer/cyclization sequence. Azomethine imines 23b, 23f–l and oxyiminium ions 29b–d are proposed as intermediates, which undergo 1,5‐hydride shift to give the tertiary carbocation 24b, 24f–l or 31b–d. The nucleophilic addition of the hydrazine or hydroxylamine moiety to the benzylic C‐9 carbon led to bridged azaestrone derivatives. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
A liquid chromatography‐tandem mass spectrometry method for the simultaneous determination of exemestane and its metabolite 17‐dihydroexemestane in human plasma
Authors: Corona Giuseppe , Elia Caterina , Casetta Bruno , Diana Crivellari , Rosalen Sara , Bari Mario , Toffoli Giuseppe 
Published: June 2009

AbstractA simple and sensitive liquid chromatography‐tandem mass spectrometry (LC–MS/MS) method has been developed and validated for the quantitation of exemestane (Exe) and its main metabolite 17‐dihydroexemestane (DhExe) in human plasma. The analytes were extracted by protein precipitation with acetonitrile, containing stable 13C‐labelled Exe (13C3‐Exe) as internal standard, and measured by LC–MS/MS. The best chromatographic separationof the analytes from the interferences was achieved by using a Phenyl column operating under isocratic regime conditions. The total chromatographic runtime was 5.0 min and the elution of Exe and DhExe occurred at 2.5 min and 2.9 min, respectively. Quantitation was performed by employing the positive electrospray ionization (ESI) technique and multiple reaction monitoring mode (MRM). The monitored precursor to product‐ion transitions for Exe, DhExe and 13C3‐Exe internal standard were m/z 297.0 → 120.8, m/z 299.1 → 134.9 and m/z 300.0 → 123.2, respectively. The lower limit of quantitation (LLOQ) was 0.1 ng/ml for DhExe and 0.2 ng/ml for Exe. The method was linear up to 36–51 ng/ml with r2 ≥ 0.998. The intra‐ and inter‐assay precision were ≤7.7% and 5.1% for Exe and ≤8.1 and 4.9% for DhExe while deviations from nominal values were in the 1.5–13.2% and − 9.0–5.8% ranges for Exe and DhExe, respectively. The analytical method resulted robust and suitable for pharmacokinetic monitoring of Exe and its main metabolite during adjuvant therapy in patients with breast cancer. Copyright © 2009 John Wiley & Sons, Ltd.
Effects of dietary microalgae, other lipid sources, inorganic selenium and iodine on yolk n‐3 fatty acid composition, selenium content and quality of eggs in laying hens
Authors: Rizzi Laura , Bochicchio Davide , Bargellini Annalisa , Parazza Paola , Simioli Marco 
Published: June 2009

AbstractBACKGROUND: This aim of this study was to investigate the effects of supplementing laying hen diets with different n‐3 fatty acid sources (linseed oil, fish oil and microalgae) on egg quality and fatty acid profile. The addition of inorganic selenium (Se) and iodine (I) and their effects on egg characteristics and Se concentration were also evaluated.RESULTS: A significantly lower egg weight was found in the control group and in groups fed a diet containing fish oil or a diet containing microalgae plus Se and I. Yolks from all supplemented diet groups exhibited a significant reduction in n‐6 fatty acid content compared with the control group. The docosahexaenoic acid (DHA) content of yolks was higher (P < 0.01) in all supplemented diet groups. Selenium supplementation increased the Se concentration (P < 0.001) in eggs.CONCLUSION: The results of this study provide evidence that an improvement in egg weight and in the DHA content of yolks can be achieved by feeding hens a microalgae‐rich diet, which avoids the unpleasant flavours associated with fish oil supplementation. Dietary inorganic Se, especially in combination with I, can enhance the concentration of Se in eggs. Copyright © 2009 Society of Chemical Industry
A comparison of MS/MS‐based, stable‐isotope‐labeled, quantitation performance on ESI‐quadrupole TOF and MALDI‐TOF/TOF mass spectrometers
Authors: Kuzyk Michael A. , Ohlund Leanne B. , Elliott Monica H. , Smith Derek , Qian Hong , Delaney Allen , Hunter Christie L. , Borchers Christoph H. 
Published: June 2009

AbstractThe peptide‐based quantitation accuracy and precision of LC‐ESI (QSTAR Elite) and LC‐MALDI (4800 MALDI TOF/TOF) were compared by analyzing identical Escherichia coli tryptic digests containing iTRAQ‐labeled peptides of defined abundances (1:1, 2.5:1, 5:1, and 10:1). Only 51.4% of QSTAR spectra were used for quantitation by ProteinPilot Software versus 66.7% of LC‐MALDI spectra. The average protein sequence coverages for LC‐ESI and LC‐MALDI were 24.0 and 18.2% (14.9 and 8.4 peptides per protein), respectively. The iTRAQ‐based expression ratios determined by ProteinPilot from the 57 467 ESI‐MS/MS and 26 085 MALDI‐MS/MS spectra were analyzed for measurement accuracy and reproducibility. When the relative abundances of peptides within a sample were increased from 1:1 to 10:1, the mean ratios calculated on both instruments differed by only 0.7–6.7% between platforms. In the 10:1 experiment, up to 64.7% of iTRAQ ratios from LC‐ESI MS/MS spectra failed S/N thresholds and were excluded from quantitation, while only 0.1% of the equivalent LC‐MALDI iTRAQ ratios were rejected. Re‐analysis of an archived LC‐MALDI sample set stored for 5 months generated 3715 MS/MS spectra for quantitation, compared with 3845 acquired originally, and the average ratios differed by only 3.1%. Overall, MS/MS‐based peptide quantitation performance of offline LC‐MALDI was comparable with on‐line LC‐ESI, which required threefold less time. However, offline LC‐MALDI allows the re‐analysis of archived HPLC‐separated samples.