bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of bis‐triethoxysilane endcapped polyurethane/urea and its self‐assembly morphologies with the assistance of hydrogen ion
Authors: Gao Feng , Huang Shiqiang , Ku Bin , Chen Ming , Wu Jun , Wang Jinzhao 
Published: March 2011

AbstractA type of bi‐triethoxysilane endcapped polyurethane/urea (SPU) with well‐defined structure was synthesized through the reaction of polyethylene glycol (PEG), 2, 4‐toluene diisocyanate (TDI) and bis‐[trimethoxysiylpropyl]amine (DB‐520). The structure of the resultant product was confirmed by Fourier transform infrared (FT‐IR) and Nuclear magnetic resonance (1HNMR). Different SPU nanoparticles were obtained with the assistance of hydrogen ion, and their morphologies were characterized by combination of transmission microscopy (TEM) and FT‐IR. The results showed that with increasing the concentration of hydrogen ions, the ratio of condensation accordingly increased, accompanying with the nanoparticle's morphology change from sphere to rod. Furthermore, the dispersion mechanism of SPU chains in protonic solution and the arrangement of molecular chains in hybrid particles were proposed. Copyright © 2011 John Wiley & Sons, Ltd.
Quantitative determination of superoxide in plant leaves using a modified NBT staining method
Authors: Grellet Bournonville Carlos F. , Díaz‐Ricci Juan Carlos 
Published: March 2011

AbstractIntroduction – In plants, the ROS (reactive oxygen species) level is tightly regulated because their accumulation produces irreversible damage leading to cell death. However, ROS accumulation plays a key role in plant signaling under biotic or abiotic stress. Although various methods were reported to evaluate ROS accumulation, they are restricted to model plants or provide only qualitative information.Objective – Develop a simple method to quantify superoxide radicals produced in plant tissues, based on the selective extraction of the formazan produced after nitroblue tetrazolium (NBT) reduction in histochemical staining.Methodology – Plant leaves were stained with a standard NBT method and the formazan precipitated in tissues was selectively extracted using chloroform. The organic phase was dried and formazan residue dissolved in dimethylsulfoxide–potassium hydroxide and quantified by spectrophotometry. The method was tested in strawberry plant leaves under different stressing conditions.Results – Formazan extracted from leaves subjected to stress conditions showed similar absorption spectra to those obtained from standard solutions using pure formazan. Calibration curves showed a linear relationship between absorbance and formazan amounts, within the range 0.5–8 µg. Outcomes suggested that formazan was retained in the solid residue of leaf tissues. This protocol allowed us to quantify superoxide radicals produced under different stress conditions.Conclusions – Chloroform allowed a selective formazan extraction and removal of potential endogenous, exogenous or procedural artefacts that may interfere with the quantitative determination. This protocol can be used to quantify the superoxide produced in plant tissues using any traditional qualitative NBT histochemical staining method.
Derivation of power gain for three types of three dimensional photovoltaics cells
Authors: Flicker Jack , Ready Jud 
Published: March 2011

AbstractIn order to quantify the higher power output seen from solar cells with a three‐dimensional (3D) topology due to the increased interactions between photons and the cell surface, we have derived a formula for the average number of interactions, Γ, between a photon and the cell surface for 3D cells with vertical sidewalls and flat tops. We have derived Γ for three different cell morphologies, an infinite trench in the x‐ or y‐direction, an enclosed box, and an infinite two‐dimensional (2D) array of towers. Monte Carlo simulations were carried out in order to compare computational results for Γ with those derived. For varying distance between features, d, and photon azimuthal angle, the data fits the derived expressions quite well for a large range of values. For varying tower height, the data fits theory well for both the trench and box morphologies, however, theory overestimates the value of Γ for the 2D array of towers. This is due to simplifications made when deriving Γ. However, the error associated with Γ is small enough that it propagates to a measured power output error of less than 1% for cells with an absorbance efficiency of at least 25%. Even with simplifications, the derived expression for Γ should be usable for predicting the increased power output for 3D cells with vertical sidewalls and flat tops. Copyright © 2011 John Wiley & Sons, Ltd.
Operating regimes for second generation luminescent solar concentrators
Authors: Farrell Daniel J. , Yoshida Megumi 
Published: March 2011

ABSTRACTIn this paper, we introduce the concept of first and second generation luminescent solar concentrators. Traditional, first generation devices are characterised by their randomly oriented molecules that absorb sunlight and emit luminescence isotropically. By applying detailed balance to the absorbed and emitted photon fluxes we derive the Shockley–Queisser limit for these devices. It is found that they have inherently low efficiency due to optical losses (the well known reabsorption problem) and also that device performance is strongly affected by the areal ratio between the top and edge surfaces. This latter property makes it very difficult to achieve significant cost reductions because as the edge area is reduced (to lessen the amount of expensive photovoltaic material required for conversion), the efficiency of the system diminishes. First generation concentrators have now approached the fundamental limits which we predict here, thus to achieve a stand‐alone luminescent concentrator that enables significant cost reductions, second generation approaches are now needed. New, second generation devices are characterised by either directional emitters or photonic filters which enhance the waveguiding mechanism, allowing high efficiency and large sizes to be achieved simultaneously. Here we define the fundamental operating regime in which second generation technology must reach to surpass the limit of first generation devices. Copyright © 2011 John Wiley & Sons, Ltd.
Strom aus der Wüste. DLR‐Studien zum Projekt Desertec
Authors: Trieb Franz 
Published: March 2011

AbstractStudien des DLR über das Potenzial erneuerbarer Energien in Europa, dem Mittleren Osten und Nordafrika kommen zu folgenden Aussagen: Ausgehend von einem existierenden Anteil von 16 % erneuerbarer Energie im Jahr 2000 könnte 2050 ein Anteil von 80 % erreicht werden. Zur Ergänzung der erneuerbaren Energiequellen wird eine effiziente Backup‐Infrastruktur benötigt. Sie liefert eine sichere, bedarfsgerechte Stromkapazität mit schnell reagierenden, erdgasbetriebenen Spitzenlastkraftwerken. Der Stromtransport nach Europa erfolgt mit Hochspannungs‐Gleichstrom‐Übertragung (HGÜ). Wird zwischen 2020 und 2050 mit einem Stromtransfer von 60 TWh/a begonnen, so könnte dieser bis auf 700 TWh/a im Jahr 2050 ausgebaut werden. Die hohe Sonnenstrahlung in MENA und niedrige Übertragungsverluste mit HGÜ von circa 10 % werden in einem konkurrenzfähigen Strompreis von circa 0,05 Euro2000/kWh resultieren. Anstelle einer zu erwartenden Verdoppelung der Kohlendioxidemissionen bis zum Jahr 2050 können diese auf 38 % der Emissionen des Jahres 2000 reduziert werden. Für den gesamten erneuerbaren Kraftwerkspark in EU‐MENA werden 1 % der Landfläche benötigt. Das entspricht der gegenwärtigen Landnutzung für Transport und Verkehr in Europa.
Wenn das Licht den Dreh raus hat. Künstliche chirale Materialien
Authors: Thiel Michael , Gansel Justyna K. , Wegener Martin , von Freymann Georg 
Published: March 2011

AbstractChirale Strukturen sind in der Natur allgegenwärtig. Optisch äußert sich Chiralität durch eine Drehung der linearen Polarisation des Lichts. Bei den meisten natürlichen Substanzen sind diese Drehungen allerdings sehr klein, da die Wellenlänge des Lichts um ein Vielfaches größer ist als die chiralen Bauelemente. Die heutige Nanotechnologie erlaubt es, chirale Strukturen auf der Skala der Wellenlänge des Lichts zu realisieren. Dadurch verstärkt sich die Wechselwirkung mit dem Licht dramatisch. Es öffnen sich Polarisationsstoppbänder, die die Ausbreitung von Licht mit einer bestimmten zirkularen Polarisation vollständig unterdrücken können.
Eine kurze Geschichte der Gezeiten. Ebbe und Flut
Authors: Glebe Wolfgang 
Published: March 2011

AbstractEbbe und Flut haben auf der Erde ihre Ursache in der Gravitation von Sonne und Mond. Diese zeitabhängigen Effekte hängen von der Stellung des Mondes relativ zur Sonne, der Neigung der Erdachse zur Sonnen‐ und Mondbahn sowie zahlreichen anderen Parametern ab. Diese zeitabhängigen Effekte wirken periodisch. Hinzu kommt die von geografischen Gegebenheiten abhängende “Reaktion” der Ozeane auf die Gezeitenkraft. Hierbei spielen auch Interferenzen von Flutwellen eine Rolle.
Magnetoelektrische Kopplung an Metalloberflächen
Authors: Gerhard Lukas , Ernst Arthur 
Published: March 2011

AbstractBei vielen gängigen Speichermedien wie Festplatten wird die Information magnetisch geschrieben und gelesen. Höhere Speicherdichten könnten Verfahren ermöglichen, bei denen man die magnetische Struktur eines Festkörpers durch ein elektrisches Feld ändert. In enger Zusammenarbeit zwischen dem Max‐Planck‐Institut für Mikrostrukturphysik, der Universität in Halle und dem Karlsruher Institut für Technologie ist es gelungen, mit Hilfe einer solchen magnetoelektrischen Kopplung die magnetische Ordnung in metallischen Nanostrukturen durch ein elektrisches Feld zwischen zwei stabilen Zuständen hin‐ und herzuschalten.
Sehen und nicht gesehen werden
Authors: Rolfs Claus 
Published: March 2011

AbstractAn der Augenstellung eines Tieres kann man seine Ernährungsweise ablesen. Jäger, wie Katze, Löwe oder Eule, haben stets beide Augen nach vorne gerichtet. Dadurch ist ihr Gesichtsfeld nach hinten zwar drastisch eingeschränkt, aber nach vorne überlappen sich die beiden Sehfelder ihrer Augen stark. Das hilft ihnen, eine Beute scharf anzupeilen. Gejagte Tiere wie Kaninchen oder Goldfische haben hingegen die beiden Augen an der Seite des Kopfes, so dass sie möglichst weit nach hinten sehen können, ohne den Kopf zu drehen. So haben sie stets die gesamte Umgebung im Blick.
Multicomponent supramolecular thermoplastic elastomer with peptide‐modified nanofibers
Authors: Wisse Eva , Spiering A. J. H. , Dankers Patricia Y. W. , Mezari Brahim , Magusin Pieter C. M. M. , Meijer E. W. 
Published: March 2011

AbstractBioactive nanofibers present a promising synthetic niche for in vivo applications due to their morphological and functional resemblance to the extracellular matrix. Potentially interesting nanofibers are constructed from the hard‐segment regimes in well‐defined thermoplastic elastomers (TPEs). The supramolecular interactions between these hard segments cause physical crosslinking by the formation of nanofibers and provide excellent mechanical properties. Here, we make use of a new class of biocompatible supramolecular TPEs, in which both the formation of the main chain and the hard block is based on multiple hydrogen‐bonding interactions. A self‐assembly process is explored to arrive at well‐defined peptide‐modified nanofibers embedded in a biocompatible soft matrix. Crucial for the success in the synthetic design is the use of an exact match between the molecular recognition units of the peptide and the supramolecular unit that takes care of forming the supramolecular nanofibers of the TPE. Evidence for the strong anchoring of the modified peptides in the hard‐segment nanofibers of the supramolecular TPE is provided by simple extraction experiments. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011
Noisy breathing and hemidiaphragm paralysis progressing to respiratory failure in an infant
Authors: Baughn Julie , Gershan William , Rao Aparna 
Published: March 2011

AbstractSpinal muscular atrophy with respiratory distress (SMARD1) is a rare autosomal recessive disease that is caused by mutations in the gene encoding for immunoglobulin µ‐binding protein 2. Unlike the relatively more common spinal muscular atrophy, patients with SMARD1 have respiratory distress prior to manifestation of distal muscle weakness making the diagnosis a challenge. Because respiratory distress is a hallmark feature of this disease, pediatric pulmonologists should recognize its features, and consider it as a diagnostic entity. Pediatr. Pulmonol. 2011; 46:817–819. © 2011 Wiley‐Liss, Inc.
Inflammation and remodeling in infantile, juvenile, and adult allergic sensitized mice
Authors: Carnieli Denise S. , Yoshioka Eliane , Silva Luiz Fernando F. , Lanças Tatiana , Arantes Fernanda M. , Perini Adenir , Martins Milton A. , Saldiva Paulo Hilário N. , Dolhnikoff Marisa , Mauad Thais 
Published: March 2011

AbstractBackgroundAirway structural changes occur early in childhood asthma, but it is unknown whether the development of airway alterations in children is similar to that of adults. We compared inflammation and remodeling parameters in allergic sensitized infantile, juvenile, and adult mice.MethodsInfantile mice (18D) were sensitized with three intraperitoneal injections (i.p.) of ovalbumin (OVA) at days 5 and 7 and challenged with OVA at days 14–16. The 18D1 group received an additional challenge at days 9–11. The juvenile mice (40D) received challenges at days 22–24 and 36–38. Adult mice (100D) were sensitized at days 60–62 and received three inhalations at days 77–79 and 96–98. Animals were submitted to whole body plethysmography. Airway eosinophils, CD3+ T‐lymphocytes, IL‐5+ cells, mucus content, collagen and reticular fibers density, and smooth muscle thickness were quantified.ResultsAll sensitized animals presented with airway hyperresponsiveness, without differences in eosinophil cell density. The density of CD3+ T‐cells was higher in the 100D and 18D1 groups than in the 18D and 40D groups. Infantile sensitized groups demonstrated increased interleukin‐5 expression in the airways. Infantile mice demonstrated more mucus in the bronchiolar epithelium than the 40D and 100D mice. The 18D animals demonstrated less collagen than the 18D1 group. Juvenile and adult mice had increased airway smooth muscle thickness when compared to age‐matched controls, but no differences were observed in the infantile groups.ConclusionWe have shown that infantile mice develop inflammatory and structural alterations in the airways that are partially different from those developed in older animals. Pediatr. Pulmonol. 2011; 46:650–665. © 2011 Wiley‐Liss, Inc.
Peculiarities of string theory on AdS4 × CP3
Authors: Sorokin D. , Wulff L. 
Published: March 2011

AbstractWe review peculiar features of type IIA string theory compactified on AdS4 × CP3 superspace, in particular, the structure of the Green–Schwarz action, issues with fixing its kappa–symmetry, classical integrability and the string instanton on CP3.
Discovering the landscape: gravitational waves from first order transitions during inflation
Authors: Chialva D. 
Published: March 2011

AbstractScenarios such as the string landscape present the possibility of having various first order transitions during the evolution of the early Universe, specifically during inflation. The gravitational waves emitted from the physical processes related to these first order phase transitions carry clear information regarding the physics that produced them. We study the features of the waves and find that they differ both from those of waves generated via quantum oscillations of the metric in vacuum and both from those of waves sourced by transitions occurring outside inflation. We also investigate the detectability of the waves.
Field theory on Schrödinger space‐time
Authors: Blau M. , Hartong J. , Rollier B. 
Published: March 2011

AbstractThe Schrödinger space‐time plays an important role in the context of non‐relativistic holography. We discuss causal structure properties of the Schrödinger space‐time by probing it with point particles as well as with scalar fields. We show that even though the causal structure seen by point particles is almost pathological (absence of a time function) this is not so for the scalar fields. We highlight Galilean‐like causal structure properties.
A scan of universal breathing‐mode reductions
Authors: Gauntlett J.P. , Varela O. 
Published: March 2011

AbstractThe near horizon limits of M2 and D3 branes probing special holonomy cones give rise to supersymmetric AdS4 × M7 and AdS5 × M5 solutions of D = 11 and type IIB supergravity, respectively, where M7 and M5 are special types of Einstein spaces. Here we will show the existence of consistent Kaluza‐Klein truncations of D = 11 and type IIB supergravity on such M7 and M5 down to matter‐coupled supergravities in D = 4, 5. We explicitly discuss some details of the particular cases when M7 and M5 are Sasaki‐Einstein.
Insights into the mechanisms of action of host defence peptides from biophysical and structural investigations
Authors: Bechinger Burkhard 
Published: March 2011

AbstractIn order to better understand the mechanisms of action of linear cationic host defense peptides, biophysical and structural investigations of their interactions with membranes and with other biomacromolecules are reviewed. In particular, an extensive overview will be given of the topological studies of magainins in a number of different lipid environments. Furthermore, amphipathic helices have been designed in such a manner to allow the easy control of their membrane alignment. These peptides not only exhibit potent antimicrobial and transfection activities, but their investigation has also provided important insights into mechanistic aspects of their biological functions. Copyright © 2011 European Peptide Society and John Wiley & Sons, Ltd.
Nano‐beam electron diffraction evaluation of strain behaviour in nano‐scale patterned strained silicon‐on‐insulator
Authors: Hähnel Angelika , Reiche Manfred , Moutanabbir Oussama , Blumtritt Horst , Geisler Holm , Hoentschel Jan , Engelmann Hans‐Jürgen 
Published: March 2011

AbstractA major challenge for the application of strain engineering to enhance the performance of electronic devices is the quantification of strain on the nanoscale. Besides other techniques (Raman spectroscopy, X‐ray diffraction) electron beam techniques allow strain analyses with a spatial resolution of a few nanometers and a reasonable strain sensitivity of 1 × 10–3 (relative to the lattice constant of silicon). In the present work, we address practical issues in the application of nano‐beam electron diffraction (NBED) to probe the strain in strained silicon layers and sub‐100 nm structures. The investigated specimens were prepared on biaxially tensile strained silicon‐on‐insulator substrates with an initial strain of ε = 0.6% or 0.8%. Results of the NBED experiments were compared to data obtained by other strain measurement techniques; amongst them the strain mapping by peak‐pairs analysis of high‐angle annular dark field (HAADF) images was especially considered (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
High‐resolution photoinduced transient spectroscopy of defect centres in semi‐insulating GaP
Authors: Kamiński Paweł , Kozłowski R. , Strzelecka S. , Hruban A. , Jurkiewicz‐Wegner E. , Piersa M. 
Published: March 2011

AbstractHigh‐resolution photoinduced transient spectroscopy (HRPITS) has been applied to study electronic properties of point defects in semi‐insulating (SI) GaP obtained by high temperature annealing under phosphorus (P) vapour pressure. The parameters of defect centres are extracted from the photocurrent relaxation waveforms, recorded in a wide temperature range of 30–600 K, by means of a two‐dimensional spectral analysis based both on the correlation procedure and inverse Laplace transform algorithm. The defect structure of GaP wafers whose SI properties resulted from the annealing under the P vapour pressures of ∼0.05 MPa and ∼0.2 MPa is compared (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Influence of ion beam on optical properties of GaAs: Calculation using the fractional‐derivative‐spectrum method
Authors: Kulik Miroslaw , Rzodkiewicz Witold , Drozdziel Andrzej , Pyszniak Krzysztof 
Published: March 2011

AbstractSemiconductor GaAs (100) was implanted with In+ at a room temperature. Fluences of implanted ions were from 1x 1012 cm‐2 to 3x1013 cm‐2 and the energy was equal to 85 keV. The detectability of the indium content in near surface layer of GaAs has been studied with the use of the secondary ion mass spectrometry (SIMS). The depths distribution of a indium concentration measured by SIMS method ware compared with depth profiles calculated with the help of SATVAL code. It was noticed that calculated profiles are in a good agreement with the measured values. Additionally, the concentration of indium in the near surface layer increased with growing of the implantation fluence and a maximum of these profiles shift in the side of ions exposed surfaces of GaAs. This effect can be explained by self‐diffusion process of target atoms and indium during the implantation. The fractional derivative spectrum (FDS) model in connection with spectroscopic ellipsometry ES was used for particular optical analyses of implanted GaAs substrates. The FDS is especially promising technique when the limitations of the standard treatment by Lorentz shape line analysis occur and it is very helpful to extract basic information on relevant physical quantities from the detected εE2(E) spectra determined by spectroscopic ellipsometry. In particular, using spectroscopic ellipsometry and FDS, the critical points E1 and E1+Δ observed in the εE2(E) spectra in the implanted substrates have been investigated. The differences in complex refractive index and dielectric function (ε=ε1+iε2) between GaAs substrate before and implantation were observed. Moreover, the several nanometres thick oxide layer on GaAs surface was detected. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Impact of singular‐vector‐based satellite data thinning on NWP
Authors: Bauer Peter , Buizza Roberto , Cardinali Carla , Noël Thépaut Jean 
Published: March 2011

AbstractSingular‐vector(SV)‐based selective satellite data thinning is applied to the Southern Hemisphere (SH) extratropics to reduce analysis uncertainty and forecast error. For two seasons, the European Centre for Medium‐Range Weather Forecasts (ECMWF) four‐dimensional variational data assimilation system has been run in five different configurations with different satellite data coverage: two reference experiments used low‐density and high‐density coverage over the globe; in the SH two SV‐based selective thinning experiments used low‐density data everywhere apart from targeted regions; and one random‐based thinning experiment used low‐density data everywhere apart from randomly defined regions. The SV‐based target regions have been defined either by daily operational SVs computed for the ECMWF Ensemble Prediction System, or by the previous year's mean seasonal distribution.Results indicate that the impact of the additional data largely depends on the season. Overall, forecast errors grow faster in the SH cold season than in the warm season. In the SH cold season, the general impact of adding data is smaller and the relative difference between the impact of the individual targeting experiments is smaller as well. In the cold season, the data assimilation system failed to extract the meteorological signal carried by the extra satellite data in sensitive regions. In the SH warm season, all experiments with more data produce a statistically more significant and longer‐lasting positive impact on forecast skill. In this season, the SV‐based targeting experiment performs best and as well as the reference experiment in which the data density is increased globally. Copyright © 2011 Royal Meteorological Society