bluuebunny/crossref_metadata_2025_split huggingface dataset:
Accuracy of prenatal diagnosis and prediction of lethality for fetal skeletal dysplasias
Authors: Yeh Peter , Saeed Ferha , Paramasivam Gowrishankar , Wyatt‐Ashmead Josephine , Kumar Sailesh 
Published: March 2011

AbstractObjectivesWe reviewed all cases with fetal skeletal dysplasia and correlated the accuracy of prenatal diagnoses with the final post‐mortem, radiological, or molecular diagnoses. The accuracy of prenatal prediction of lethality was also reviewed.MethodsAll cases of fetal skeletal dysplasia referred between October 2002 and August 2010 were reviewed. Perinatal outcome, the accuracy of prenatal diagnosis, and prediction of lethality were ascertained. Lethality was suspected when significant thoracic narrowing, severe micromelia, multiple fractures, or long bone bowing was present.ResultsThere were 40 cases of skeletal dysplasia. Thirty‐nine (97.5%) were singletons and one (2.5%) was a dichorionic twin pregnancy. Twenty‐eight (70%) pregnancies were terminated, five (12.5%) were stillborn, and only seven (17.5%) cases were live born. A final diagnosis was established in 28 (70%) cases. In 29 cases with a presumptive prenatal diagnosis, this was confirmed in 23 (79.3%) cases postnatally. Lethality was predicted with 100% certainty.ConclusionWe report higher prenatal/postnatal concordance rates in this series. A precise prenatal diagnosis is frequently difficult and often inaccurate. Prediction of lethality is much easier and often possible with accuracy. Parents need to be aware that the outcome of many skeletal dysplasias is poor. Copyright © 2011 John Wiley & Sons, Ltd.
Viscoelasticity of concentrated polyacrylonitrile solutions: effects of solution composition and temperature
Authors: Tan Lianjiang , Wan Ajun , Pan Ding 
Published: March 2011

AbstractThe effects of solution composition and temperature on the viscoelasticity of concentrated polyacrylonitrile (PAN) solutions were studied using a variety of rheological measurements, such as steady‐state shearing, dynamic stress sweep and transient rheological tests. The first normal stress difference N1 and the shear stress τ were found to increase with decreasing temperature and increasing PAN concentration and water content in the solutions. The crossover point of N1 and τ, denoting the equal contribution of viscosity and elasticity to the viscoelasticity of the solutions, moved to lower shear rates at lower temperature, higher PAN concentration and higher water content. The values of the relaxation time (λ) were larger at 70 °C than at 40 °C. In addition, the changes of λ with PAN concentration and water content were different at the two temperatures, ascribed to the different states of the solutions. The PAN solutions were in the linear viscoelastic regime in the temperature range 40–70 °C when the shear stress was below 300 Pa. The creep compliance recovery rate decreased with increasing temperature, but increased with increasing PAN concentration and water content. Thixotropic tests showed that the thixotropy of the solutions was also affected by the solution composition and temperature. Gelation was found to influence the way the solution composition and temperature affected the viscoelastic properties of the PAN solutions. Copyright © 2011 Society of Chemical Industry
Dual glassy relaxations in physically aged semi‐crystalline poly(L‐lactic acid)
Authors: Shieh Yeong‐Tarng , Jho Jia‐Cing , Wang Tzong‐Liu , Yang Chien‐Hsin , Su Chean‐Cheng 
Published: March 2011

AbstractSemi‐crystalline poly(L‐lactic acid) (PLLA) was physically aged below the glass transition temperature for various times to investigate its amorphous phase behavior. During a differential scanning calorimetry heating scan, dual enthalpy recovery endotherms were found to appear in the glass transition region of PLLA, aged at 52 °C, of a particular degree of crystallinity (Xc) within a definite range. Below the lower Xc limit, only the low endotherm corresponding to the free amorphous phase was observed; above the upper Xc limit, only the high endotherm corresponding to the constrained amorphous phase was observed. Dual tan δ peaks in dynamic mechanical analysis confirmed the coexistence of the dual amorphous phases. Both lower and upper limits of the Xc range increased with an increase in isothermal crystallization temperature from the melt. Long‐term physical aging at 52 °C, which did not affect Xc, allowed the evolution of the free amorphous phase to the constrained amorphous phase in PLLA with Xc within the definite range. The effects of physical aging at various temperatures on the enthalpy recovery endotherms were also investigated. Copyright © 2011 Society of Chemical Industry
Progress with epitaxy wrap‐through crystalline silicon thin‐film solar cells
Authors: Mitchell Emily J. , Brinkmann Nils , Reber Stefan 
Published: March 2011

AbstractWafer‐Equivalents are thin‐film solar cells that use a low‐cost silicon substrate to epitaxially grow a high‐quality crystalline silicon active layer. The epitaxy wrap‐through (EpiWT) cell is a back‐contact version of the Wafer‐Equivalent that aims to increase currents and gain other benefits of back contacts. The EpiWT cell can be made in a symmetrically interdigitated configuration with 50% back emitter coverage, or using an isolation layer to lower the back emitter coverage to ∼10%, which will theoretically increase voltages. The epitaxial deposition through via holes in the substrate depends on many factors, including the sealing of the deposition chamber, and produces various thicknesses and geometrical forms of the layers in the holes. An extended process has been developed to incorporate a passivated selective emitter and the first batch has been fabricated. The best result was an efficiency of 13.2% with ∼22 µm base layer thickness. The results are limited most by the fill factors at this stage, e.g. 75% for this cell, which is due to a processing difficulty encountered with screen‐printing in via holes. A new isolation layer was tested and successfully implemented for the low back‐emitter configuration. Comparable voltages and currents were achieved but the fill factors were lower than for the 50% back emitter cells, resulting in a best efficiency of 11.2%. Copyright © 2011 John Wiley & Sons, Ltd.
Optimization of SiN AR coating for Si solar cells and modules through quantitative assessment of optical and efficiency loss mechanism
Authors: Kang Moon Hee , Ryu Kyungsun , Upadhyaya Ajay , Rohatgi Ajeet 
Published: March 2011

ABSTRACTPlasma‐enhanced chemical vapor deposition (PECVD) SiN films are widely used as antireflection (AR) coating for silicon solar cells and particularly for multi‐crystalline solar cells for hydrogen passivation of bulk defects. In this paper, the detailed optical properties of various SiN films and their effect on silicon solar cell efficiency in air and under glass is evaluated by a combination of Monte‐Carlo geometrical ray tracing program, Sunrays, and a device modeling program PC1D. Maximum module power under glass and ethylene vinyl acetate (EVA) encapsulation is used as the figure of merit for optimizing the index and thickness of the SiN films. Simulations are categorized by surface morphology (planar or textured) and ambient (air or glass). SiN films with refractive index (n) in the range of 2.03–2.42 are used for this study. It is found that although n = 2.03 is not the optimum index in terms of reflectance under glass (n = 1.5), it produces maximum cell or module efficiency under glass. This is because n = 2.03 film produces much higher cell efficiency (17.9%) in air, therefore, even after a significant optical encapsulation loss of 0.8% in absolute efficiency, the cell efficiency remains highest (17.1%) under glass. In contrast SiN film with an index of 2.4 produces only 0.5% air to glass efficiency loss but due to the low starting efficiency of 17% in air; the final cell efficiency under glass is only 16.5%. In addition, texturing provides a larger window of thickness around the optimum without affecting the optical performance. Similar analysis done for planar cells indicate that optimum index for highest module power is 2.20. This is because reflection is much higher in planar cells, therefore higher index can be tolerated before loss due to absorption in SiN exceeds the gain in reflectance under glass. Copyright © 2011 John Wiley & Sons, Ltd.
Der einäugige Riese. Das European Extremely Large Telescope
Authors: Kissler‐Patig Markus 
Published: March 2011

AbstractDas European Extremely Large Telescope (E‐ELT) wird mit einem Primärspiegel von 42 m Durchmesser das größte Teleskop werden, das die Menschheit je gebaut hat. Diese europäische Großforschungsanlage wird bis zum Ende des Jahrzehnts in der Atacama‐Wüste im Norden Chiles errichtet. Innovativ ist die komplette Regelung der Optiken, inklusive der Echtzeitkompensation der Turbulenzen der Erdatmosphäre. Mit 1200 m2 Lichtsammelfläche und der 16‐fachen Winkelauflösung des Weltraumteleskops Hubble wird das E‐ELT ein Teleskop der Superlative. Neben einer Vielfalt von Forschungsprojekten ist das Hauptziel des E‐ELT die Charakterisierung der Atmosphären von Exoplaneten.
Ein Außenseiter als Atomist
Authors: Loos Andreas 
Published: March 2011

AbstractWoraus besteht Luft? Wie viele Atome Sauerstoff und Wasserstoff ergeben ein Wassermolekül? Fragen dieser Art sind heute Schulstoff, im ausgehenden 18. Jahrhundert waren sie Zündstoff. Dutzende Chemiker, Physiker und Amateure konkurrierten mit ihren Theorien.
Lichtsammelkomplexe in der Küche
Authors: Vilgis Thomas 
Published: March 2011

AbstractGemüsefarbstoffe gelten unter Ernährungsexperten als kleine Gesundheitswunder. Auch in der Biophysik spielen die elektronenreichen Moleküle eine ganz besondere Rolle, denn sie sind Teil des Fotosyntheseapparats. Der beschert der Pflanze ihr Wachsen und Gedeihen, indem er über Elektronen Lichtenergie in chemische Reaktionen umwandelt. Auch in der Küche lässt sich mit dem grünen Farbstoff Chlorophyll bestens experimentieren.
Dreidimensionale Abbildung magnetischer Domänen
Authors: Manke Ingo , Kardjilov Nikolay , Strobl Markus , Banhart John 
Published: March 2011

AbstractMagnetische Domänen bilden die Grundlage für das Verständnis vieler magnetischer Phänomene und der Eigenschaften magnetischer Materialien. Ihre Existenz hat Pierre‐Ernest Weiss bereits 1907 vorhergesagt, weshalb sie als Weiss‐Bezirke bezeichnet werden. Mittlerweile gibt es zwar mehrere Verfahren zur Visualisierung magnetischer Domänen. Sie sind jedoch alle auf die zweidimensionale Abbildung, zumeist an Oberflächen oder in dünnen Schichten, beschränkt. Am Zentrum für Materialien und Energie Berlin (HZB) hat unsere Gruppe eine Methode entwickelt, mit der sich das gesamte Netzwerk magnetischer Domänen sowie auch einzelne individuelle Domänenformen im Inneren von magnetischen Materialien dreidimensional abbilden lassen.
Identification of differentially expressed proteins in blood plasma of control and cigarette smoke‐exposed mice by 2‐D DIGE/MS
Authors: Tewari Arun K. , Popova‐Butler Alexandra , El‐Mahdy Mohamed A. , Zweier Jay L. 
Published: March 2011

AbstractCigarette smoke exposure is known to induce obstructive lung disease and several cardiovascular disease states in humans and also in animal models. Smoking leads to oxidative stress and inflammation that are important in triggering pulmonary and cardiovascular disease. The objective of the current study was to quantify differences in expression levels of plasma proteins of cigarette smoke ‐exposed and control mice, at the time of disease onset, and identify these proteins for use as potential biomarkers of the onset of smoking‐induced disease. We utilized 2‐D DIGE/MS to characterize these proteomic changes. 2‐D DIGE of plasma samples identified 11 differentially expressed proteins in cigarette smoke ‐exposed mice. From these 11 proteins, 9 were downregulated and 2 were upregulated. The proteins identified are involved in vascular function, coagulation, metabolism and immune function. Among these, the alterations in fibrinogen (2.2‐fold decrease), α‐1‐antitrypsin (1.8‐fold increase) and arginase (4.5‐fold decrease) are of particular interest since these have been directly linked to cardiovascular and lung pathology. Differences in expression levels of these proteins were also confirmed by immunoblotting. Thus, we observe that chronic cigarette smoke exposure in mice leads to prominent changes in the protein expression profile of blood plasma and these changes in turn can potentially serve as markers predictive of the onset and progression of cardiovascular and pulmonary disease.
Protein expression profiling in the zebrafish (Danio rerio) embryos exposed to the microcystin‐LR
Authors: Li Guangyu , Chen Jun , Xie Ping , Jiang Yan , Wu Laiyan , Zhang Xuezhen 
Published: March 2011

AbstractMicrocystin‐leucine‐arginine (MCLR) is the most toxic and the most commonly encountered variant of microcystins (MCs) in aquatic environment, and it has the potential for developmental toxicity. A number of previous studies have described the developing toxicity of MCLR based on conventional toxicological indices. However, the molecular mechanisms by which it expresses its toxicity during the early development remain largely unknown. To further our understanding of mechanisms of action and identify the potential protein biomarkers for MCLR exposure, a proteomic analysis was performed on developing zebrafish embryos exposed to 0.5 mg/L MCLR until 96 hours post‐fertilization. 2‐DE combined with MS was employed to detect and identify the protein profiles. Results showed that 75 spots from the 0.5 mg/L MCLR condition showed a significant increase or decrease in abundance compared with the control. In total, 40 proteins were identified. These proteins were mainly included in process related to oxidative stress, energetic metabolism, and the cytoskeleton assembly. MCLR exposure also affects the expression of the subunits of protein phosphatases 2A. Furthermore, the proteomic and transcriptional analysis of nine proteins was determined by Western blot and quantitative real‐time PCR due to their correlation with the known MCLR toxic mechanisms. The consistent and discrepant results between protein and mRNA levels indicated complicated regulatory mechanisms of gene expression in response to MCLR exposure.
Interaction of water‐soluble triphenylphosphines with β‐cyclodextrin: a quantum chemistry study
Authors: Sayede Adlane , Ferreira Michel , Bricout Hervé , Tilloy Sébastien , Monflier Eric 
Published: March 2011

AbstractThe interaction of β‐cyclodextrin (β‐CD) with meta‐trisulfonated triphenylphosphine derivatives bearing one or two methyl (or methoxy) groups on the aromatic rings has been investigated by PM3 calculations. The results show that phosphine molecules interact with β‐CD having either an unsubstituted sulfophenyl group or a substituted sulfophenyl group at the para and/or meta‐position. The presence of one methyl or methoxy group in the ortho‐position on each aromatic ring prevents the formation of an inclusion complex between meta‐trisulfonated triphenylphosphine derivatives and β‐CD. The deeply included phosphines in the β‐CD cavity show significant van der Waals interactions with β‐CD. These interactions are at the origin of the high association constants between these molecules and β‐CD. Phosphines exhibiting small association constants interact with β‐CD by forming H‐bonds and weak (or null) van der Waals interactions. Copyright © 2011 John Wiley & Sons, Ltd.
Consistent truncations with massive modes and holography
Authors: Cassani D. , Dall'Agata G. , Faedo A.F. 
Published: March 2011

AbstractWe review the basic features of some recently found consistent Kaluza–Klein truncations including massive modes. We emphasize the general ideas underlying the reduction procedure, then we focus on type IIB supergravity on 5‐dimensional manifolds admitting a Sasaki–Einstein structure, which leads to half‐maximal gauged supergravity in five dimensions. Finally, we comment on the holographic picture of consistency.
Dynamical gauge fields in holographic superconductors
Authors: Silva P.J. 
Published: March 2011

AbstractHolographic superconductors have been studied so far in the absence of dynamical electromagnetic fields, namely in the limit in which they coincide with holographic superfluids. It is possible, however, to introduce dynamical gauge fields if a Neumann‐type boundary condition is imposed on the AdS‐boundary. In 3 + 1 dimensions, the dual theory is a 2 + 1 dimensional CFT whose spectrum contains a massless gauge field, signaling the emergence of a gauge symmetry. We study the impact of a dynamical gauge field in vortex configurations where it is known to significantly affect the energetics and phase transitions.
Instabilities and doubly spinning black holes
Authors: Astefanesei D. , Rodriguez M.J. , Theisen S. 
Published: March 2011

AbstractUltra‐spinning black holes in higher dimensions have qualitatively similar thermodynamical properties to the black strings/p‐branes– they exhibit a black membrane‐like phase. In these notes we will explore which doubly spinning black holes and black rings show this black membrane‐like phase and pinpoint the threshold of these regimes. For the same cases we will study the thermodynamical instabilities in the grand canonical ensemble and compute the zeros of the Hessian of the Gibbs potential. Comparing our results, we will show that the thresholds of the black membrane phase and the thermal instability do not necessarily coincide.
Electronic energy levels of RbCdBr3 crystal
Authors: Demirbilek R. , Bozdoğan A. Çelik , Çalışkan M. , Özen G. 
Published: March 2011

AbstractThe RbCdBr3 crystal that consists of edge shared [CdBr6]4− octahedrons was grown by using the Bridgman growth technique and its electronic energy levels are investigated by measuring the excitation and the emission spectra. An energy level diagram for electronic energy levels of RbCdBr3‐crystal is constructed by using the observed excitation spectra and symmetry considerations.
Self‐diffusion in silicon – Change of a paradigm
Authors: Seeger Alfred 
Published: March 2011

AbstractDiffusion processes play a key role in the fabrication of semiconductor devices. For a long time the underlying mechanisms were thought to be analogous to those in metals, based on vacancies as thc dominant lattice defects in thermal equilibrium. From the mid‐sixties onwards it became clear that this picture is invalid for Si, where strongly relaxed self‐interstitials are dominant and responsible for self‐ and Group‐III‐ diffusion. Inter alia, this change of a paradigm led to novel concepts and to the quantitative explanation of the diffusion of so‐called hybrids such as Au, Pt, and Zn in Si by the so‐called kick‐out mechanism.
Image instability during the electrical measurement in scanning electron microscope
Authors: Kumagai Kazuhiro , Yao Yuanzhao , Chen Jun , Sekiguchi Takashi 
Published: March 2011

AbstractDuring electrical measurements in a scanning electron microscope (SEM), secondary electron (SE) images often become dark or the image contrast becomes weaker. We have revealed that this phenomenon originates in the negative charging of the insulating part in an electric circuit. This charging can be caused by stray electrons, even if the insulator is not directly irradiated. The electrostatic field owing to this charge deflects SEs and reduces the intensity of detected electrons. We have demonstrated this effect by observing systematic shifts of the field of view of SE detector, which appears in SE images. This explanation is supported by a calculation of electron trajectories in the electrostatic field in the SEM chamber. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
CL and dark field TEM analysis of composition change at interfaces in InGaP/GaAs junctions grown by MOCVD
Authors: Frigeri C. , Shakhmin A. A. , Vinokurov D. A. , Zamoryanskaya M. V. 
Published: March 2011

AbstractDark field transmission electron microscopy by using both the (200) two beam diffraction mode and the high angle annular dark field (HAADF) method has been used to check the presence and composition of unwanted layer(s), that had formed at the place of the nominal 10 nm thick GaAs QW grown on top of the InGaP barrier in MOCVD InGaP/GaAs samples, and whose existence was suggested by cathodoluminescence. It is shown that the nominal 10 nm GaAs QW has been replaced by 2 layers: a thin one made of In0,15Ga0,85As0,80P0.20 closer to InGaP followed by a second one made of either GaAs0.91P0.09or In0,05Ga0,95As0,84P0.16. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Time‐resolved cathodoluminescence on polychromatic light emitting (In,Ga)N quantum wells grown on (11‐22) GaN facets
Authors: Corfdir Pierre , Simeonov Dobri , Feltin Eric , Carlin Jean‐François , Lefebvre Pierre , Grandjean Nicolas , Deveaud‐Plédran Benoît , Ganière Jean‐Daniel 
Published: March 2011

AbstractWe present a low‐temperature time‐resolved cathodoluminescence study on (In,Ga)N/GaN quantum wells grown on the (11‐22) facets of non‐coalesced ELO‐GaN. Taking advantage of the quantum confined Stark effect, such structures have been proposed as promising monolithic white light emitters. Here, we show that in order to achieve solar‐like white light emission from this kind of structure, one has to pay attention on the respective evolutions of radiative and non‐radiative QW exciton decay times along the (11‐22) facets (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Cathodoluminescence study of individual ZnO nanorods
Authors: Gruzintsev A. N. , Red'kin A. N. , Yakimov E. E. , Yakimov E. B. 
Published: March 2011

AbstractInvestigations of individual ZnO nanorod cathodoluminescence (CL) spectra and of low energy electron beam irradiation effect on their optical properties were carried out. The spatially inhomogeneous distribution in the CL emission excitation was observed in some nanorods. The dependence of CL spectra on the nanorod size was revealed. It was shown that the defect‐related luminescence is practically absent in these samples. It was observed that the CL intensity of nanorods increased after a short irradiation time with low energy electron beam and then started to decrease (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
High bandgap dielectrics for antireflective coating in silicon solar cells by reactive ion sputtering
Authors: Kaminski P. M. , Bass K. , Claudio G. 
Published: March 2011

AbstractHigh bandgap materials have recently attracted a lot of interest for their potential application in photovoltaics (PV). Aluminium nitride (AlNx) is a potential candidate for the passivation and antireflective coating on silicon solar cells. AlNx thin films have been deposited by a remote plasma deposition system HiTUS (High Target Utilisation Sputtering). The AlNx thin films were grown by reactive sputtering from an aluminium target in a N2 atmosphere, negating the use of silane gas commonly used in PECVD deposition. PC1D simulations have been performed to calculate the best thickness for an antireflective coating for silicon wafers. Several depositions have been performed at different substrate temperatures. Photo conductive measurements by a WCT‐100 were performed on silicon wafer after each thermal process to measure the effective minority carrier lifetime of p‐type crystalline silicon wafer boron doped 〈100〉. Reflectance measurements were performed for samples prepared at different bias and flow gas ratios. Results show that the coating provides reflection reduction to levels below 5% for samples with a thickness of 70 nm. An increase in carrier lifetime has been observed for AlN deposited at high temperature. Annealing at 400 °C has been shown to increase carrier lifetime to 12 µs compared to 7 µs, suggesting the potential of AlN for silicon passivation and an alternative antireflective coating (ARC) to silicon nitride. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)