bluuebunny/crossref_metadata_2025_split huggingface dataset:
V5116 Sgr: A disc‐ecipsed SSS post‐outburst nova?
Authors: Sala G. , Hernanz M. , Ferri C. , Greiner J. 
Published: February 2010

AbstractNova V5116 Sgr 2005 No. 2, discovered on 2005 July 4, was observed with XMM‐Newton in March 2007, 20 months after the optical outburst. The X‐ray spectrum showed that the nova had evolved to a pure supersoft X‐ray source, indicative of residual H‐burning on top of the white dwarf. The X‐ray light‐curve shows abrupt decreases and increases of the flux by a factor 8 with a periodicity of 2.97 h, consistent with the possible orbital period of the system. The EPIC spectra are well fit with an ONe white dwarf atmosphere model, with the same temperature both in the low and the high flux periods. This rules out an intrinsic variation of the X‐ray source as the origin of the flux changes, and points to a possible partial eclipse as the origin of the variable light curve. The RGS high resolution spectra support this scenario showing a number of emission features in the low flux state, which either disappear or change into absorption features in the high flux state. A new XMM‐Newton observation in March 2009 shows the SSS had turned off and V51 16 Sgr had evolved into a weaker and harder X‐ray source (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Supersoft X‐ray sources and the progenitors of Type Ia supernovae
Authors: Podsiadlowski Ph. 
Published: February 2010

AbstractSupersoft X‐ray sources have been proposed as one of the major channels to produce Type Ia supernovae (SNe Ia). However, the true nature of the progenitors has remained an unsolved problem. In this review I summarize the present status of our understanding of SN Ia progenitors, the main classes of progenitor models and recent observational constraints. At present, neither the single‐degenerate nor the double‐degenerate model can be ruled out, and indeed more than one channel may be required to explain the observed SN Ia diversity. Finally, I discuss the origin of the lightcurve peak – lightcurve width relation (the ‘Phillips relation’) and show that it is expected to depend on metallicity; this needs to be taken into account in high‐precision cosmological applications (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The outburst properties of AM CVn stars
Authors: Kotko I. , Lasota J.‐P. , Dubus G. 
Published: February 2010

AbstractWe briefly summarise the observational properties of ultra‐compact binaries called AM CVn stars. We analyse their outbursts originating from the thermal‐viscous instability in helium accretion disc. We present our preliminary results in applying the model of Dwarf Novae outbursts to helium discs. We can calculate models of outbursts of reasonable amplitude of 2 mag with a constant α parameter throughout the calculation. Setting the mass transfer rate close to its upper critical value produces model lightcurves that resemble short superoutbursts (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Supersoft X‐ray sources
Authors: Haberl F. 
Published: February 2010

AbstractThe workshop “Supersoft X‐ray Sources – New Developments” brought together observers and theoretician to discuss the present status and unsolved problems of supersoft source research. A large part of the workshop was devoted to optical novae and their supersoft state. Large samples of supersoft X‐ray sources were presented from nearby galaxies, as well as extensive monitoring campaigns ofbright individual sources. The theoretical modelling oflight curves and high‐resolution X‐ray spectra are well underway, but details are often not yet understood (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The diversity of FtsY‐lipid interactions
Authors: Reinau M. E. , Thøgersen I. B. , Enghild J. J. , Nielsen K. L. , Otzen D. E. 
Published: February 2010

AbstractThe bacterial signal recognition particle (SRP) receptor FtsY forms a complex with the SRP Ffh to target nascent polypeptide chains to the bacterial inner membrane. How FtsY interacts with lipids and associates to the membrane is unclear. Here, we show that vesicle binding leads to partial protection against proteolytic degradation and a change in secondary structure, which differs depending on whether the lipids are simple mixtures of zwitterionic and anionic lipids, mimics of Escherichia coli lipids, or lysolipids. Lipid binding alters the stability of FtsY. Thermal unfolding of FtsY in buffer shows two transitions, one occurring at ∼60°C and the other at ∼90°C. The thermal intermediate accumulating between 60 and 90°C has structural features in common with the state induced by binding to E. coli lipids. E. coli lipid extract induces a single transition around 70°C, anionic lipids have no effect while cooperative unfolding is completely removed in lysolipids. Thus, the lipid environment profoundly influences the dynamic properties of FtsY, leading to three different kinds of FtsY‐lipid interactions with different effects on structure, proteolytic protection, and stability, and is driven both by hydrophobic and electrostatic interactions. Trypsin digestion experiments highlight the central role of the N‐domain in lipid contacts, whereas the A‐ and G‐domains appear to play a more minor part. © 2010 Wiley Periodicals, Inc. Biopolymers 93: 595–606, 2010.This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Insight into the stability of cross‐β amyloid fibril from molecular dynamics simulation
Authors: Chen Yue , He Yong‐Jie , Wu Maoying , Yan Guanwen , Li Yixue , Zhang Jian , Chen Hai‐Feng 
Published: February 2010

AbstractAmyloid fibrils are considered to play causal roles in the pathogenesis of amyloid‐related degenerative diseases such as Alzheimer's disease, type II diabetes mellitus, the transmissible spongiform encephalopathies, and prion disease. The mechanism of fibril formation is still hotly debated and remains an important open question. In this study, we utilized molecular dynamics (MD) simulation to analyze the stability of hexamer for eight class peptides. The MD results suggest that VEALYL and MVGGVV‐1 are the most stable ones, then SNQNNY, followed by LYQLEN, MVGGVV‐2, VQIVYK, SSTSAA, and GGVVIA. The statistics result indicates that hydrophobic residues play a key role in stabilizing the zipper interface. Single point and two linkage mutants of MVGGVV‐1 confirmed that both Met1 and Val2 are key hydrophobic residues. This is consistent with the statistics analysis. The stability results of oligomer for MVGGVV‐1 suggest that the intermediate state should be trimer (3‐0) and tetramer (2‐2). These methods can be used in stabilization study of other amyloid fibril. © 2010 Wiley Periodicals, Inc. Biopolymers 93: 578–586, 2010.This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Mechanical valve dysfunction after percutaneous perimitral leak closure: Salvage by percutaneous occluder retrieval
Authors: Brilakis Emmanouil S. , Collins Laura J. , Obel Owen , Banerjee Subhash 
Published: February 2010

AbstractPercutaneous closure of perivalvular regurgitation may be complicated by prosthetic valve impingement and dysfunction. We describe a patient with two perimitral defects who developed severe mitral stenosis due to mitral leaflet impingement after percutaneous implantation of three amplatzer muscular ventricular septal defect occluder devices. The largest amplatzer occluder device was successfully snared with restoration of normal prosthetic valve motion. © 2010 Wiley‐Liss, Inc.
Combined mechanical and pharmacological approach to a thrombus‐containing lesion
Authors: Ben‐Dor Itsik , Pichard Augusto D. , Waksman Ron 
Published: February 2010

AbstractDistal embolization during primary percutaneous coronary intervention for acute myocardial infarction is associated with impaired myocardial perfusion and poor outcome. Numerous pharmacological and mechanical strategies have been proposed to prevent and treat distal embolization. A successful combined mechanical and pharmacological approach to a large thrombus‐containing lesion in patients with acute coronary syndrome is described. A review of the current literature regarding the drugs and devices available for the prevention and treatment of large thrombus burden has also been performed. © 2010 Wiley‐Liss, Inc.
Input Multiplicity Analysis in a Non‐Isothermal CSTR for Acid‐Catalyzed Hydrolysis of Acetic Anhydride
Authors: Jayakumar N. S. , Hashim M. A. , Thomas M. T. 
Published: February 2010

AbstractMultiplicity analysis gives practical guidance for process design to eliminate difficult operating regions associated with input and output multiplicities. Continuous stirred tank reactors (CSTRs) present challenging operational problems due to complex behavior such as input and output multiplicities, ignition/extinction, parametric sensitivity, and nonlinear oscillations. In the absence of a unified mathematical theory for representing various nonlinear system characteristics, the present study was aimed at understanding the dynamic behavior of CSTRs by means of experiments and to link the experimental data to theoretical considerations for further detection and elimination of operating problems. Theoretical modeling and analysis of a non‐isothermal CSTR with acid‐catalyzed hydrolysis of an acetic anhydride system for input multiplicity are discussed. Theoretical modeling of a non‐isothermal CSTR using a root‐finding technique was carried out for predicting steady‐state temperatures. Alternatively, a mathematical model for a non‐isothermal CSTR using unsteady‐state mass and energy balance equations is proposed. Computer‐based simulation was carried out using a program developed in MATLAB for final transient temperature and time‐temperature data of the CSTR system under investigation. The results of a theoretical analysis conducted for confirming the existence of input multiplicity in non‐isothermal CSTRs with acid‐catalyzed hydrolysis of acetic anhydride were compared with experimental investigations for validation.
Supercritical CO2 Extraction of Essential Oil from Algerian Rosemary (Rosmarinus officinalis L.)
Authors: Zermane A. , Meniai A.‐H. , Barth D. 
Published: February 2010

AbstractThe present study presents experimental results concerning the supercritical CO2 extraction of essential oil from Algerian rosemary leaves. The effects of key operating parameters such as pressure, temperature, particle size and CO2 mass flow rate on the extraction yield were investigated. The obtained yields were in the range of 0.95–3.52 g oil/g dry rosemary, and the best value was observed at a pressure of 22 MPa, a temperature of 40 °C, a flow rate of 7 g/min, and a particle size of 1 mm. The performance of the local rosemary used was assessed by comparison of the obtained yields with values reported in the literature for essential oils derived from different rosemary sources. The GC and the GC‐MS analyses showed that the major compound detected in the essential oil was camphor, at 48.89 wt %.
Influence of Water and Supercooling on Permeability and Compressibility of Acrylic Acid Crystal Beds
Authors: Hengstermann A. , Harms S. , Jansens P. 
Published: February 2010

AbstractThe performance of a solid‐liquid separation process is often limited by size distribution and morphology of the crystals. To predict the filtration behavior, a robust and applicable model based only on crystallization process parameters is necessary. Therefore, a model has been successfully developed for the industrial system of aqueous acrylic acid melt to predict compressibility and permeability of a crystal bed. For this purpose, common equations are transferred successfully to nonspherical particles. Chord length distributions (CLDs) obtained from an inline focused beam reflectance measurement (FBRM) probe and crystal aspect ratios have been used in combination to determine the major input parameters for the model. Integration of a complex mathematical restoration of crystal size distribution (CSD) from CLD data by the use of existing models is avoided. Considering acceptable fault tolerances of the model, a simple approach used as a robust industrial application is employed. The adjustment of all required constants used in the permeability model was based on simple filtration tests.
A New Approach for Process Development of Plant‐Based Extraction Processes
Authors: Kassing M. , Jenelten U. , Schenk J. , Strube J. 
Published: February 2010

AbstractOver the last few years the impact of products from natural sources in food, nutraceuticals, cosmetics, flavors/fragrances, and also the pharmaceutical industry has increased due to the consumer demand for nature‐derived products. Meeting this demand requires that existing manufacturing processes have to be optimized and process development for a variety of new products, sometimes with short life cycles, has to be accelerated. A scientific literature review covering equipment and modeling for plant‐based extractions shows an enormous demand for new approaches in process design for solvent extraction, isolation, and purification of ingredients from botanical sources and its transfer from academic research into manageable solutions for industrial use. An approach combining the design of experiments and rigorous process modeling on the one hand and an intensified collaboration between different disciplines including process engineering, botany, and analytical chemistry on the other hand seems to be the only way forward to address the current issues and shortcomings systematically and efficiently. Hence, a standard apparatus for the assessment of the governing process parameters for plant‐based extraction processes is proposed.
Synthesis of Monomeric and Dimeric Repeating Units of the Zwitterionic Type 1 Capsular Polysaccharide from Streptococcus pneumoniae
Authors: Wu Xiangyang , Cui Lina , Lipinski Tomasz , Bundle David R. 
Published: February 2010

AbstractZwitterionic polysaccharides (ZPSs) from Bacteroides fragilis and Streptococcus pneumoniae display unique T‐cell activities. The first synthesis of a hexasaccharide representing two repeating units of the zwitterionic capsular polysaccharide from S. pneumoniae type 1 (Sp1) is reported. Key elements of the approach are stereoselective construction of 1,4‐cis‐α‐galactose linkages based on a reactive trichloroacetimidate donor that incorporates a 6‐O‐acetyl group, which may contribute to the high α selectivity in glycosylation. After assembly of the fully protected hexasaccharide from five monosaccharide synthons 2–4, 24 and 25, selective deprotection of the primary hydroxyl groups of the four galactose residues followed by oxidation to the corresponding uronic acids provides hexasaccharide 19. The trisaccharide counterpart 1 was synthesized in similar fashion from three synthons, 2–4. This approach employed both conventional and dehydrative glycosylation methodologies and avoids the use of poorly reactive uronic acid derived glycosyl donors and acceptors.
Speciation of Aluminium in Mixtures of the Ionic Liquids [C3mpip][NTf2] and [C4mpyr][NTf2] with AlCl3: An Electrochemical and NMR Spectroscopy Study
Authors: Rodopoulos Theo , Smith Leanne , Horne Michael D. , Rüther Thomas 
Published: February 2010

AbstractThis paper reports on the electrodeposition of aluminium on several substrates from the air‐ and water‐stable ionic liquids 1‐propyl‐1‐methylpiperidinium bis(trifluoromethylsulfonyl)amide ([C3mpip][NTf2]) and 1‐butyl‐1‐methylpyrrolidinium bis(trifluoromethylsulfonyl)amide ([C4mpyr][NTf2]), which contain anhydrous AlCl3. At an AlCl3 concentration of 0.75 molal, no evidence for aluminium electrodeposition was observed in either system at room temperature. However, aluminium electrodeposition becomes feasible upon heating the samples to 80 °C. Aluminium electrodeposition from bis(trifluoromethylsulfonyl)amide‐based ionic liquids that contain AlCl3 has previously been shown to be very dependent upon the AlCl3 concentration and has not been demonstrated at AlCl3 concentrations below 1.13 molal. The dissolution of AlCl3 in [C3mpip][NTf2] and [C4mpyr][NTf2] was studied by variable‐temperature 27Al NMR spectroscopy to gain insights on the electroactive species responsible for aluminium electrodeposition. A similar change in the aluminium speciation with temperature was observed in both ionic liquids, thereby indicating that the chemistry was similar in both. The electrodeposition of aluminium was shown to coincide with the formation of an asymmetric four‐coordinate aluminium‐containing species with an 27Al chemical shift of δ=94 and 92 ppm in the [C3mpip][NTf2]–AlCl3 and [C4mpyr][NTf2]–AlCl3 systems, respectively. It was concluded that the aluminium‐containing species that give rise to these resonances corresponds to the electroactive species and was assigned to [AlCl3(NTf2)]−.
Elucidation of Metal‐Ion Accumulation Induced by Hydrogen Bonds on Protein Surfaces by Using Porous Lysozyme Crystals Containing RhIIIIons as the Model Surfaces
Authors: Ueno Takafumi , Abe Satoshi , Koshiyama Tomomi , Ohki Takahiro , Hikage Tatsuo , Watanabe Yoshihito 
Published: February 2010

AbstractMetal‐ion accumulation on protein surfaces is a crucial step in the initiation of small‐metal clusters and the formation of inorganic materials in nature. This event is expected to control the nucleation, growth, and position of the materials. There remain many unknowns, as to how proteins affect the initial process at the atomic level, although multistep assembly processes of the materials formation by both native and model systems have been clarified at the macroscopic level. Herein the cooperative effects of amino acids and hydrogen bonds promoting metal accumulation reactions are clarified by using porous hen egg white lysozyme (HEWL) crystals containing RhIIIions, as model protein surfaces for the reactions. The experimental results reveal noteworthy implications for initiation of metal accumulation, which involve highly cooperative dynamics of amino acids and hydrogen bonds: i) Disruption of hydrogen bonds can induce conformational changes of amino‐acid residues to capture RhIIIions. ii) Water molecules pre‐organized by hydrogen bonds can stabilize RhIIIcoordination as aqua ligands. iii) Water molecules participating in hydrogen bonds with amino‐acid residues can be replaced by RhIIIions to form polynuclear structures with the residues. iv) RhIIIaqua complexes are retained on amino‐acid residues through stabilizing hydrogen bonds even at low pH (≈2). These metal–protein interactions including hydrogen bonds may promote native metal accumulation reactions and also may be useful in the preparation of new inorganic materials that incorporate proteins.
Ultrahydrophobe Oberflächen durch gezieltes Grenzflächendesign
Authors: Frenzel R. , Synytska A. , Nitschke M. , Stamm M. , Simon F. , Grundke K. 
Published: February 2010

AbstractFür viele Anwendungen ist die gezielte Einstellung der Benetzbarkeit von Festkörperoberflächen von großer Bedeutung. Ein aktueller Forschungsschwerpunkt ist die Herstellung ultrahydrophober Oberflächen, deren Anwendungspotenzial sich von selbstreinigenden Beschichtungen bis hin zum oberflächenspannungskontrollierten Flüssigkeitstransport in der Mikrofluidik erstreckt. Im Folgenden werden ausgewählte Strategien zur Erzeugung ultrahydrophober Oberflächen vorgestellt und das Wechselspiel zwischen gezielter Änderung der chemischen Zusammensetzung und der Strukturierung der Festkörperoberfläche auf die Benetzbarkeit näher beleuchtet. Am Beispiel von Kern‐Schale‐Partikeln wurden zum einen die freie Oberflächenenergie der Partikel durch das Anbinden kovalenter Polymerbürsten gezielt verändert und zum anderen hochgeordnete, aber auch ungeordnete, Oberflächentopographien aus dicht gepackten Partikeln mit unterschiedlichen Rauheiten hergestellt. Dabei wurde die Rauheit durch Verwendung von Partikeln mit unterschiedlichem Durchmesser (200 nm bis 20 μm) variiert. Oberflächen mit hierarchisch rauen Topographien wurden durch eine anodische Oxidation von Aluminium erhalten. Auf solchen Oberflächen applizierte Copolymere unterliegen einer molekularen Selbstorganisation, bei der sich hydrophobe Segmente an der Grenzfläche Polymer/Luft anreichern und so dem Material ultrahydrophobe Eigenschaften verleihen. Hydrophile Segmente reichern sich in der Grenzschicht Metalloxid/Polymer an und sorgen so für eine gute Haftungfestigkeit der polymeren Beschichtung. Hierarchisch raue Oberflächen konnten auch durch ein Plasmaätzen von Polymeren erreicht werden. Binäre Polymerbürsten, die an so vorbehandelte Oberflächen kovalent angebunden wurden, ermöglichten ein reversibles Schalten zwischen vollständiger Benetzung und Ultrahydrophobie.
Mikrotrenntechnik: Entwicklungsstand und Perspektiven
Authors: Chasanis P. , Kern J. , Grünewald M. , Kenig E. Y. 
Published: February 2010

AbstractDie Mikroverfahrenstechnik zeichnet sich durch den Einsatz von Mikrostrukturapparaten aus. Diese enthalten Strukturelemente im Mikrometerbereich. Für die Realisierung mikrotechnischer Produktionsprozesse ist die Entwicklung von Mikrotrennapparaten zur Durchführung fluidverfahrenstechnischer Grundoperationen unentbehrlich. In diesem Artikel wird ein Überblick über Forschungsentwicklungen auf dem Gebiet der Mikrotrenntechnik gegeben. Der Schwerpunkt wird hierbei auf die Grundoperationen Extraktion, Absorption/Desorption und Destillation gelegt.
Modellbasierte Bestimmung lokal gültiger Kinetiken chemischer Reaktionen in Flüssigphase mittels Flachbettmikroreaktor*
Authors: Warnecke H.‐J. , Bothe D. , Zrenner A. , Berth G. , Hüsch K.‐P. 
Published: February 2010

AbstractStrömungsbasierte Mischprozesse sind grundlegender Bestandteil vieler chemischer Prozesse. Realisierbare Mischzeiten reichen von einigen Millisekunden bis zu Sekunden, wobei die vollständige Homogenisierung oft nicht sichergestellt ist. Werden kinetische Parameter chemischer Reaktionen dieses Zeitskalenbereichs ohne Berücksichtigung der Mischprozesse bestimmt, sind sie mischungsmaskiert und geben die inhärente chemische Kinetik nicht wieder. In dieser Arbeit wird die Validierung und Anwendung einer Methode zur Bestimmung inhärenter chemischer Kinetiken von in Flüssigphase ablaufenden chemischen Reaktionen im stationären, laminaren Flachbettmikroreaktor vorgestellt. Der verfolgte Ansatz basiert auf der mechanistischen Modellierung der Molmengen unter Berücksichtigung von Konvektion, Diffusion und Reaktion und der Bestimmung der unbekannten Parameter durch Anpassung des Modells an experimentell ermittelte Konzentrationsverläufe.
CFD‐Anwendungen für Rührkesselreaktoren in der Bioverfahrenstechnik
Authors: Eslahpazir Esfandabadi M. , Hempel D. C. , Krull R. 
Published: February 2010

AbstractIn den vergangenen Jahren hat sich die numerische Strömungssimulation (Computational Fluid Dynamics, CFD) sehr schnell zu einem wichtigen Werkzeug der fluiddynamischen Beschreibung von einphasig und mehrphasig betriebenen Rührkesselreaktoren in der (Bio‐) Verfahrenstechnik entwickelt. So können CFD‐Simulationen recht zuverlässige Informationen, u. a. über die qualitative und quantitative Bestimmung von Strömungsfeldern, die Transportvorgänge zwischen den einzelnen Phasen, die Verbesserung der Produktivität durch Modifizierung der Rührergeometrie sowie den Einfluss der mechanischen Beanspruchung auf belebte oder unbelebte Partikelagglomerate, liefern. In diesem Artikel werden die Herausforderungen und Anwendungen bezüglich der Modellimplementierung, der Einflüsse der Reaktorgeometrie und der Gitterzellenzahl, der experimentellen Validierungsmethoden (Experimental Fluid Dynamics, EFD) sowie der Einbindung und Identifizierung von Quell‐ und Verbrauchstermen in die Impulsbilanz diskutiert.