bluuebunny/crossref_metadata_2025_split huggingface dataset:
Towards Engineering Nanoporous Platinum Thin Films for Highly Efficient Catalytic Applications
Authors: Jung Hyun Young , Kim Do Hyung , Chun Hyun Kyung , Kim Sang Hoon , Lim Chae Sun , Byun Ji Young , Jung Yung Joon 
Published: September 2011

AbstractPorous metals attract significant interest for use in diverse electrochemical catalytic applications. However the fabrication of scalable and controlled porous metal structures on the nanoscale, particularly with highly catalytic pure Pt, still remains a significant challenge. We demonstrate highly engineered nanoporous Pt thin films by the dealloying of a Pt‐Si binary alloy system with a predetermined alloy composition. Controlled pore dimensions and nanostructures are obtained by tailoring the Pt‐Si alloy composition followed by selective Si etching. As a result, isotropic open nanopores are formed in continuous Pt ligaments and the porosity becomes larger on increasing the Si/Pt atomic ratio, which leads to the formation of a higher surface area and active catalytic sites. The formed nanoporous Pt film shows a 32‐times‐higher catalytic activity than Pt/C catalysts, with a high current density and low charge‐transfer resistance during methanol electro‐oxidation. The results reported here open up possibilities to develop high‐performance and reliable catalytic electrodes in energy and environmental applications.
Komplexe von N‐heterocyclischen Carbenen mit Boranen: Synthese und Reaktionen
Authors: Curran Dennis P. , Solovyev Andrey , Makhlouf Brahmi Malika , Fensterbank Louis , Malacria Max , Lacôte Emmanuel 
Published: September 2011

AbstractBorane sind weit verbreitete Lewis‐Säuren, und N‐heterocyclische Carbene (NHCs) sind beliebte Lewis‐Basen. Dennoch war bis in die jüngste Zeit erstaunlich wenig über Komplexe dieser beiden Verbindungsklassen miteinander bekannt. NHC‐Borane sind leicht herzustellen, und teilweise sind sie so stabil, dass sie weniger als Komplex, sondern vielmehr als eigenständige organische Verbindung betrachtet werden können. Sie verhalten sich nicht wie klassische Borane, und sie können ein breites Spektrum an funktionellen Gruppen enthalten. Als vielseitige Reaktionspartner, Reagentien und Katalysatoren verfügen NHC‐Borane über ein immenses Potenzial für die organische Synthese und die Polymerchemie. Viele Reaktionen von NHC‐Boranen laufen über neue reaktive Intermediate wie Boreniumkationen, Borylradikale und sogar Borylanionen ab. Hier geben wir eine umfassende Übersicht über die Synthese, Charakterisierung und Reaktionen von NHC‐Boranen.
Selective hydrosilylation of ketones catalyzed by in situ‐generated iron NHC complexes
Authors: Buitrago Elina , Zani Lorenzo , Adolfsson Hans 
Published: September 2011

AbstractAryl alkyl‐, heteroaryl alkyl‐ and dialkyl ketones were readily reduced to their corresponding secondary alcohols in high yields, using the commercially available and inexpensive polymeric silane polymethylhydrosiloxane (PMHS), as reducing agent. The reaction is catalyzed by an in situ‐generated iron complex, conveniently generated from iron(II) acetate and the commercially available N‐heterocyclic carbene (NHC) precursor IPr·HCl. Copyright © 2011 John Wiley & Sons, Ltd.
From poly(dialkylstannane)s to poly(diarylstannane)s: comparison of synthesis methods and resulting polymers
Authors: Lechner Marie‐Luise , Trummer Markus , Bräunlich Irene , Smith Paul , Caseri Walter , Uhlig Frank 
Published: September 2011

AbstractThe efficiency and applicability of three different methods to synthesize polystannanes with different side chains are described. By means of dehydrogenative coupling utilizing the transition metal catalyst RhCl(PPh3)3 (Wilkinson's catalyst), n‐Bu2SnH2 reached the highest molar masses. Dehydrogenetive coupling in the presence of tetramethylethylenediamine could be best employed for (4‐n‐BuPh)2SnH2. Wurtz coupling using sodium in liquid ammonia was best suited for Ph2SnCl2. Next to the above‐mentioned educts, n‐Bu(Ph)SnX2 (X = H or Cl (as appropriate for the particular route) was used for polymerization resulting in one of so far rare example of asymmetric polystannanes with high molecular masses. Copyright © 2011 John Wiley & Sons, Ltd.
Polymer‐supported macrocyclic Schiff base palladium complex as an efficient catalyst for the Heck reaction
Authors: He Ying , Cai Chun 
Published: September 2011

AbstractA polymer‐supported macrocyclic Schiff base palladium complex has been synthesized. In the Heck reaction of aryl iodides and bromides with ethyl acrylate or styrene, the complex has been proved to give the corresponding products in good to excellent yields. The reaction proceeded smoothly in the presence of 0.5 mol% of catalyst in DMF within 1–4 h. Recycling studies have shown that the catalyst can be readily recovered and reused for four cycles with only a slightly decrease in its activity. Copyright © 2011 John Wiley & Sons, Ltd.
Catalytic activity of cycloaurated complexes in the addition of 2‐methylfuran to methyl vinyl ketone
Authors: Kilpin Kelly J. , Jarman Bevan P. , Henderson William , Nicholson Brian K. 
Published: September 2011

AbstractCycloaurated gold(III) complexes derived from cycloaurated iminophosphorane, triphenylphosphine sulfide or selenide, or pyridylsulfonamide ligands have been assessed for their catalytic activity in the addition of 2‐methylfuran to methyl vinyl ketone. Addition of AgBF4 was generally needed for high activity, although those with coordinated atoms of high trans influence showed some activity in the absence of added Ag+. Copyright © 2011 John Wiley & Sons, Ltd.
Self‐complementary multiple hydrogen bonding interactions increase the glass transition temperatures to supramolecular poly(methyl methacrylate) copolymers
Authors: Kuo Shiao‐Wei , Tsai Hsin‐Tung 
Published: September 2011

AbstractWe have prepared a series of poly(methyl methacrylate) (PMMA)‐based copolymers through free radical copolymerization of methyl methacrylate in the presence of 2‐ureido‐4[1H]‐pyrimidinone methyl methacrylate (UPyMA). The glass transition temperature was increased with the increase of UPyMA contents in PMMA copolymers due to strong self‐complementary multiple hydrogen bonding interactions of UPy moiety. The Fourier transform infrared and solid‐state NMR spectroscopic analyses provided positive evidence for the presence of multiple hydrogen bonds interaction of UPy moiety. Furthermore, the proton spin‐lattice relaxation time in the rotating frame [T1ρ(H)] for the PMMA copolymers had a single value that was less than pure PMMA, indicating the smaller domain sizes in PMMA copolymers. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Use of a Plackett–Burman statistical design to determine the effect of selected amino acids on monoclonal antibody production in CHO cells
Authors: González‐Leal I. J. , Carrillo‐Cocom L. M. , Ramírez‐Medrano A. , López‐Pacheco F. , Bulnes‐Abundis D. , Webb‐Vargas Y. , Alvarez M. M. 
Published: September 2011

AbstractCulture media design is central to the optimization of monoclonal antibody (mAb) production. Although general strategies do not currently exist for optimization of culture media, the combined use of statistical design and analysis of experiments and strategies based on simple material balances can facilitate culture media design. In this study, we evaluate the effect of selected amino acids on the growth rate and monoclonal antibody production of a Chinese hamster ovary DG‐44 (CHO‐DG44) cell line. These amino acids were selected based on their relative mass fraction in the specific mAb produced in this study, their consumption rate during bioreactor experiments, and also through a literature review. A Plackett–Burman statistical design was conducted to minimize the number of experiments needed to obtain statistically relevant information. The effect of this set of amino acids was evaluated during exponential cell culture (considering viable cell concentration and the specific growth rate as main output variables) and during the high cell‐density stage (considering mAb final concentration and specific productivity as relevant output variables). For this particular cell line, leucine (Leu) and arginine (Arg) had the highest negative and positive effects on cell viability, respectively; Leu and threonine (Thr) had the highest negative effect on growth rate, and valine (Val) and Arg demonstrated the highest positive impact on mAb final concentration. Results suggest the pertinence of a two‐stage strategy for amino acid supplementation, with a mixture optimized for cell growth and a different amino acid mixture for mAb production at high density. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011
Finite element implementation for computer‐aided education of structural mechanics: Mohr's circle and its practical use
Authors: Lee Jae Young , Ryu Hee Ryong , Park Young Taek 
Published: September 2011

AbstractThis article introduces a computer program for computer‐aided education about Mohr's circle and its practical use. The instructional tool has been implemented as part of a finite element analysis program, VisualFEA. The proposed approach to teaching and learning Mohr's circle is distinguished from previous work by its association with practical analysis models. The Mohr's circle is displayed and operated on the basis of stress data obtained from finite element analysis whereas arbitrarily assumed numerical values are used in other programs. The analysis can be extended to elasto‐plastic models with various yield criteria. Thus, the program can be regarded not only as an instructional module for studying Mohr's circle itself, but also as a training tool for exercising its practical application. This article describes the characteristics of the program's educational features and suggests important points for teaching and learning Mohr's circle and related subjects using VisualFEA. © 2011 Wiley Periodicals, Inc. Comput Appl Eng Educ 22:494–508, 2014; View this article online at wileyonlinelibrary.com/journal/cae; DOI 10.1002/cae.10.1002/cae.20575
Perchloropyracylene and its Fusion with C60 by Chlorine‐Assisted Radio‐Frequency Furnace Synthesis
Authors: Mueller Andreas , Ziegler Karolin , Amsharov Konstantin Yu. , Jansen Martin 
Published: September 2011

AbstractElusive perchloropyracylene has been obtained during conventional fullerene synthesis in a chlorine‐containing atmosphere by using the radio‐frequency furnace technique. In contrast to its hydrocarbon analogue, the title compound was found to be unexpectedly stable. Although the high stability of perchloropyracylene impedes its direct addition to C60 fullerene, the corresponding adduct was found in the synthesis products extracted from the raw soot. Both new species were separated and unambiguously characterized by single‐crystal X‐ray analysis. According to experimental observations and quantum chemical calculations, the addition of perchloropyracylene to the C60 fullerene can only be realized by involving highly reactive species such as C14 clusters displaying the pyracylene connectivity. Such a viable mechanism includes capturing of free or partially chlorinated C14 clusters with pyracylene‐type connectivity by the fullerene molecule and subsequent stabilization through chlorine addition. The data obtained provide experimental evidence for the presence of pyracylene‐like C14 clusters in the gas phase, which have evolved during the graphite vaporization process. According to the pentagon road mechanism, such clusters are regarded as crucial intermediates in fullerene formation.
Exercises in Pyrrolidine Chemistry: Gram Scale Synthesis of a Pro–Pro Dipeptide Mimetic with a Polyproline Type II Helix Conformation
Authors: Reuter Cédric , Huy Peter , Neudörfl Jörg‐Martin , Kühne Ronald , Schmalz Hans‐Günther 
Published: September 2011

AbstractA practical and scalable synthesis of a Fmoc‐protected tricyclic dipeptide mimetic (6), that is, a 1,4‐diaza‐tricyclo‐[8.3.03, 7]‐tridec‐8‐ene derivative resembling a rigidified di‐L‐proline in a polyproline type II (PPII) helix conformation, was developed. The strategy is based on a Ru‐catalyzed ring‐closing metathesis of a dipeptide (4) prepared by PyBOP coupling of cis‐5‐vinylproline tert‐butylester (2) and trans‐N‐Boc‐3‐vinylproline (rac‐3) followed by chromatographic diastereomer separation. Building block 2 was prepared from L‐proline in six steps via electrochemical C5‐methoxylation, cyanation and conversion of the nitrile into a vinyl substituent. Building block rac‐3 was prepared in five steps exploiting a Cu‐catalyzed 1,4‐addition of vinyl‐MgBr to a 2,3‐dehydroproline derivative in the key step. In the course of the investigation subtle dependencies of protecting groups on the reactivity of the 2,3‐ and 2,5‐disubstituted pyrrolidine derivatives were observed. The configuration and conformational preference of several intermediates were determined by X‐ray crystallography. The developed synthesis allows the preparation of substantial amounts of 6, which will be used in the search for new small molecules for the modulation of protein–protein interactions involving prolin‐rich motifs (PRDs).
trans‐[Pt(BCat′)Me(PCy3)2]: An Experimental Case Study of Reductive Elimination Processes in Pt–Boryls through Associative Mechanisms
Authors: Braunschweig Holger , Bertermann Rüdiger , Brenner Peter , Burzler Michael , Dewhurst Rian D. , Radacki Krzysztof , Seeler Fabian 
Published: September 2011

AbstractA stable trans‐(alkyl)(boryl) platinum complex trans‐[Pt(BCat′)Me(PCy3)2] (Cat′=Cat‐4‐tBu; Cy=cyclohexyl=C6H11) was synthesised by salt metathesis reaction of trans‐[Pt(BCat′)Br(PCy3)2] with LiMe and was fully characterised. Investigation of the reactivity of the title compound showed complete reductive elimination of Cat′BMe at 80 °C within four weeks. This process may be accelerated by the addition of a variety of alkynes, thereby leading to the formation of the corresponding η2‐alkyne platinum complexes, of which [Pt(η2‐MeCCMe)(PCy3)2] was characterised by X‐ray crystallography. Conversion of the trans‐configured title compound to a cis derivative remained unsuccessful due to an instantaneous reductive elimination process during the reaction with chelating phosphines. Treatment of trans‐[Pt(BCat′)Me(PCy3)2] with Cat2B2 led to the formation of CatBMe and Cat′BMe. In the course of further investigations into this reaction, indications for two indistinguishable reaction mechanisms were found: 1) associative formation of a six‐coordinate platinum centre prior to reductive elimination and 2) σ‐bond metathesis of BB and CPt bonds. Mechanism 1 provides a straightforward explanation for the formation of both methylboranes. Scrambling of diboranes(4) Cat2B2 and Cat′2B2 in the presence of [Pt(PCy3)2], fully reductive elimination of CatBMe or Cat′BMe from trans‐[Pt(BCat′)Me(PCy3)2] in the presence of sub‐stoichiometric amounts of Cat2B2, and evidence for the reversibility of the oxidative addition of Cat2B2 to [Pt(PCy3)2] all support mechanism 2, which consists of sequential equilibria reactions. Furthermore, the solid‐state molecular structure of cis‐[Pt(BCat)2(PCy3)2] and cis‐[Pt(BCat′)2(PCy3)2] were investigated. The remarkably short BB separations in both bis(boryl) complexes suggest that the two boryl ligands in each case are more loosely bound to the PtII centre than in related bis(boryl) species.
Operation reduced low‐density parity‐check decoding algorithms for low power communication systems
Authors: Lin Chia‐Yu , Chou Shu‐Cheng , Ku Mong‐Kai 
Published: September 2011

SUMMARYDecoding operation reduction algorithms on min‐sum layered low‐density parity‐check (LDPC) decoders are proposed in this paper. Our algorithm freezes selected operations in high reliable nodes to reduce power while preserving error correcting performance. Both memory accesses and active node switching activities can be reduced. A novel node refresh mechanism reactivates frozen nodes to minimize coding gain degradation. We propose three decoding operation reduction algorithm variations to trade‐off complexity and operation reduction for LDPC decoders with different degrees of parallelism and memory requirement. Simulation results show that the number of LDPC decoding operations is reduced across all SNR ranges. The decoding convergence speed is not affected. Hardware architecture and FPGA implementation for IEEE 802.16e LDPC codes are presented. Copyright © 2011 John Wiley & Sons, Ltd.
Abdichtungen in und unter Mauerwerk
Authors: Oswald Rainer 
Published: September 2011

AbstractAbdichtungen in und unter Mauerwerk – darunter sind Querschnittsabdichtungen bei tragenden und nichttragenden Wänden und Fußpunktabdichtungen in Verblendschalen zu verstehen – machen in Leistungsverzeichnissen und Abrechnungen nur kleine Positionen aus. Geben solche Abdichtungen zu Mangelstreitigkeiten Anlass oder sind sie gar fehlerhaft ausgeführt und die Ursache von Schäden, so können sich diese “kleinen Positionen“ zu sehr großen Schadensposten auswachsen: Der Aufwand zur Korrektur oder zum Austausch von Abdichtungen in und unter Mauerwerk ist nämlich hoch.Der vorliegende Beitrag soll auf die wesentlichen Streitpunkte klärend eingehen.
Volkswirtschaftliche Bewertung der EnEV
Authors: Böhmer Michael , Thamling Nils 
Published: September 2011

AbstractMit dem Energiekonzept aus dem Jahr 2010 hat die Bundesregierung das Ziel formuliert, die energiebedingten Treibhausgasemissionen in Deutschland bis zum Jahr 2050 um 80 % gegenüber dem Jahr 1990 zu reduzieren. Auf den Gebäudebereich entfallen heute rund 40 % des deutschen Endenergieverbrauchs und etwa ein Drittel der CO2‐Emissionen. Auf die Bereitstellung von Raumwärme und Warmwasser in Wohngebäuden entfallen rund 25 % des deutschen Endenergieverbrauchs. Der Gebäudebestand soll bis zum Jahr 2050 nahezu klimaneutral sein. Dies bedeutet eine Reduktion des Primärenergieverbrauchs bis 2050 um 80 % gegenüber 1990 und eine Verdopplung der Sanierungsrate von aktuell etwa einem Prozent auf künftig zwei Prozent (BMU, BMWi 2010).Aus dem Energiekonzept geht weiterhin hervor, dass erhebliche Anstrengungen notwendig sein werden, um diese Ziele zu erreichen, und dass die bestehenden Instrumente hierfür nicht ausreichen werden. Die Bundesregierung plant daher umfangreiche Maßnahmen und Instrumente für den Gebäudebestand und arbeitet aktuell an deren Ausgestaltung.Wie diese Instrumente im Detail auch aussehen mögen – für private Wohnungseigentümer und für die Wohnungswirtschaft ergeben sich große Herausforderungen aus den Zielsetzungen des Energiekonzepts. Dazu sind einige grundlegende Fragen zu den ökonomischen Auswirkungen von Energieeffizienzanforderungen im Gebäudebereich einerseits und den volkswirtschaftlichen Chancen, die mit der Verfolgung dieser Ziele verbunden sind, zu klären. Im Einzelnen befasst sich dieser Beitrag mit den folgenden Fragestellungen:– Welche einzelwirtschaftlichen Effekte hatte die Verschärfung der EnEV 2007 auf das Niveau der EnEV 2009 sowie eine mögliche Fortschreibung bei Neubauten?– Welche volkswirtschaftlichen Effekte ergeben sich im Falle einer Steigerung der Bautätigkeit auf das im Energiekonzept angestrebte Niveau?– Welche klimapolitischen Effekte sind damit verbunden?
MicroCT for molecular imaging: Quantitative visualization of complete three‐dimensional distributions of gene products in embryonic limbs
Authors: Metscher Brian D. , Müller Gerd B. 
Published: September 2011

AbstractWe present a broadly applicable procedure for whole‐mount imaging of antibody probes in embryonic tissues at microscopic resolutions based on combining a metal‐based immunodetection scheme with x‐ray microtomography (microCT). The method is generally accessible, relying on standard enzyme‐conjugated secondary antibodies and other readily available reagents, and is demonstrated here with microCT visualizations of acetylated α‐tubulin in the chick nervous system and of type II collagen in developing limbs. The tomographic images offer complete three‐dimensional representations of molecular patterns obtained with immunostaining methods at the level of organ development, with added possibilities to quantify both spatial distributions and varying densities of gene products in situ. This imaging modality bridges a crucial gap in three‐dimensional molecular imaging by combining the histological resolutions of confocal microscopy with a greater specimen size range than optical projection tomography, and thus enables a powerful new approach to long‐standing issues of skeletogenic pattern formation in vertebrate limbs. Developmental Dynamics 240:2301–2308, 2011. © 2011 Wiley‐Liss, Inc.
Respiratory functions in adolescents hospitalized for anorexia nervosa: A prospective study
Authors: Kerem Nogah C. , Averin Elvira , Riskin Arieh , Tov Nave , Srugo Isaac , Kugelman Amir 
Published: September 2011

AbstractObjective:To examine the effects of malnourishment on the respiratory system of adolescents with anorexia nervosa (AN) hospitalized for medical stabilization.Method:Prospective study. Study group: hospitalized adolescents with recent onset (<1 year) AN. Control group: adolescents hospitalized for other diagnoses. Excluded: participants with lung disease.Results:Patients' characteristics (mean ± SD) for the AN (n = 16) and the control group (n = 13) on admission were: age: 15.0 ± 1.7 vs. 15.2 ± 1.4 years, p = 0.7; body mass index (BMI): 15.5 ± 2.3 vs. 19.8 ± 2.9 kg/m2, p < 0.001; venous pH 7.34 ± 0.02 vs. 7.38 ± 0.03, p < 0.001; PCO2 53.3 ± 4.1 vs. 42.5 ± 3.1 mm Hg, p < 0.001; and HCO3 28.7 ± 2.0 vs. 25.3 ± 2.4 meq/L, p < 0.001, respectively. Therewere no significant differences in nocturnal respiratory rates, pulse‐oximetry oxygen saturations, or end‐tidal CO2. Pulmonary function tests (PFTs) in adolescents with AN revealed no obstructive, restrictive, or significant pulmonary vascular disease except for lower peak expiratory flow rates (PEFRs). During hospitalization (12.3 ± 3.8 days), their weight, BMI, mean nocturnal heart rate, and respiratory rate increased significantly, while their venous PCO2 and HCO3 decreased significantly without significant changes in PFTs.Discussion:Adolescents with recent onset AN, admitted for medical stabilization, demonstrate hypercapnia despite normal PFTs, except for decreased PEFRs. These could result from decreased respiratory muscle strength and/or abnormal control of breathing. © 2011 by Wiley Periodicals, Inc. (Int J Eat Disord 2012)
Short‐Range Spin Order and Frustrated Magnetism in Mn2InSbO6 and Mn2ScSbO6
Authors: Ivanov Sergey , Nordblad Per , Mathieu Roland , Tellgren Roland , Politova Ekaterina , André Gilles 
Published: September 2011

AbstractThe complex metal oxides Mn2ASbO6 (A = In, Sc) with a corundum‐related structure A3BO6 were prepared as polycrystalline powders by a solid‐state reaction route. Their crystal structure and magnetic properties were investigated by using a combination of X‐ray and neutron powder diffraction, electron microscopy, calorimetric, and magnetic measurements. At room temperature, these compounds adopt a trigonal structure, space group R$\bar {3}$, with a = 8.9313(1) Å, c = 10.7071(2) Å (for In) and a = 8.8836(1) Å, c = 10.6168(2) Å (for Sc), which persists down to 1.6 K. The Mn and A cations were found to be randomly distributed over the A sites. The overall behavior of the magnetization of Mn2InSbO6 and that of Mn2ScSbO6 are quite similar. In spite of the relatively large amount of Mn ions on the A site, only short‐range magnetism is observed. Neutron diffraction patterns of Mn2InSbO6 showed no evidence of a long‐range magnetic ordering at 1.6 K, instead only a weak diffuse magnetic peak was observed at low temperatures. The factors governing the observed structural and magnetic properties of Mn2ASbO6 are discussed and compared with those of other Mn‐containing complex metal oxides with a corundum‐related structure. The influence of the A cation sublattice on the magnetic properties is also considered.