bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Selective Inhibitor Gal‐PUGNAc of Human Lysosomal β‐Hexosaminidases Modulates Levels of the Ganglioside GM2 in Neuroblastoma Cells
Authors: Stubbs Keith A. , Macauley Matthew S. , Vocadlo David J. 
Published: January 2009

AbstractDer hoch selektive Inhibitor Gal‐PUGNAc (siehe Bild) für die β‐Hexosaminidasen HEXA und HEXB ist zellgängig und moduliert die Aktivität von HEXA und HEXB in Gewebekulturen in einer Weise, dass die Spiegel des Gangliosids GM2 erhöht werden. Gal‐PUGNAc sollte es ermöglichen, die Rolle dieser Enzyme auf der Zellebene zu analysieren, ohne dass durch gleichzeitige Inhibition der O‐GlcNAcase ein chemisch komplexer Phänotyp entsteht.magnified image
Hydrogenation of N‐Acylcarbamates and N‐Acylsulfonamides Catalyzed by a Bifunctional [Cp*Ru(PN)] Complex
Authors: Ito Masato , Koo Lee Wei , Himizu Akio , Kobayashi Chika , Sakaguchi Ayaka , Ikariya Takao 
Published: January 2009

AbstractEs geht auch mit weniger: Der difunktionelle Komplex 1 erleichtert die Wechselwirkung mit Substraten, die weniger elektrophile Kohlenstoffatome enthalten als Ketone, Epoxide und Imide. Die Titelreaktion konnte für die Reduktion von Evans' asymmetrischen Alkylierungsprodukten zu den chiralen Alkoholen genutzt werden, wobei das chirale Oxazolidinon‐Auxiliar zurückgewonnen wurde. EWG=elektronenziehende Gruppe.magnified image
Recent Advances in the Chemistry and Biology of Naturally Occurring Antibiotics
Authors: Nicolaou K. C. , Chen Jason S. , Edmonds David J. , Estrada Anthony A. 
Published: January 2009

AbstractEver since the world‐shaping discovery of penicillin, nature's molecular diversity has been extensively screened for new medications and lead compounds in drug discovery. The search for agents intended to combat infectious diseases has been of particular interest and has enjoyed a high degree of success. Indeed, the history of antibiotics is marked with impressive discoveries and drug‐development stories, the overwhelming majority of which have their origin in natural products. Chemistry, and in particular chemical synthesis, has played a major role in bringing naturally occurring antibiotics and their derivatives to the clinic, and no doubt these disciplines will continue to be key enabling technologies. In this review article, we highlight a number of recent discoveries and advances in the chemistry, biology, and medicine of naturally occurring antibiotics, with particular emphasis on total synthesis, analogue design, and biological evaluation of molecules with novel mechanisms of action.
A Two‐State Reactivity Model Explains Unusual Kinetic Isotope Effect Patterns in CH Bond Cleavage by Nonheme Oxoiron(IV) Complexes
Authors: Klinker Eric J. , Shaik Sason , Hirao Hajime , Que Lawrence 
Published: January 2009

AbstractIt's in the bond: The cleavage of CH bonds by two related oxoiron(IV) complexes shows a range of kinetic isotope effect (KIE) values that exhibit an unusual dependence on the CH bond strength. Large nonclassical KIEs are observed for bond strengths below 93 kcal mol−1, while semiclassical values are found above this value (see graph, DHA=9,10‐dihydroanthracene). This nonintuitive behavior can be rationalized by invoking a two‐state reactivity model.magnified image
Enantioselective Intermolecular Crossed‐Conjugate Additions between Nitroalkenes and α,β‐Enals through a Dual Activation Strategy
Authors: Zhong Cheng , Chen Yunfeng , Petersen Jeffrey L. , Akhmedov Novruz G. , Shi Xiaodong 
Published: January 2009

AbstractDouble the fun: The title reaction was developed by using a Lewis base/iminium activation strategy (see scheme). The reaction proceeded with excellent yields and ee values, and the products were additionally transformed into a single enantiomer of a substituted pyrrolidine with excellent retention of configuration.magnified image
The effect of alkalization and fiber loading on the mechanical properties of bamboo fiber composites, Part 1: — Polyester resin matrix
Authors: Das Mahuya , Chakraborty Debabrata 
Published: January 2009

AbstractBamboo strips [10 cm × 1.5 cm × (1−1.5) mm] were treated with caustic solutions for 1 h at different concentrations e.g., 0, 10, 15, 20, and 25%. Bamboo strips reinforced polyester resin composites were fabricated by hand‐lay‐up technique using both alkali‐treated and untreated bamboo strips, using a room temperature curing system for the polyester resin. This study aims at the evaluation of the influence of caustic concentration on the mechanical properties of bamboo strips reinforced polyester resin composites at a constant 50% loading of reinforcement. Maximum improvement in property was achieved possibly with 20% of caustic treated strip reinforcements. Beyond 20%, there was degradation in all the strength properties because of failure in mechanical properties of the reinforcements itself. The effect of fiber loading variation upon mechanical properties was also studied. It was observed that superior mechanical properties were obtained with 60% filler loading. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Polyimides based on aromatic diisocyanates containing pendent flexible alkoxy chains and aromatic dianhydrides: Synthesis, characterization, and liquid‐crystal alignment properties
Authors: Sarkar Anjana , Halhalli Mahadeo R. , Kulkarni Arun D. , Wadgaonkar Prakash P. 
Published: January 2009

AbstractFour new aromatic diisocyanates containing pendent flexible alkoxy chains, namely, 5‐butyloxy‐1,3‐phenylenediisocyanate, 5‐octyloxy‐1,3‐phenylenediisocyanate, 5‐dodecyloxy‐1,3‐phenylenediisocyanate, and 5‐hexadecyloxy‐1,3‐phenylenediisocyanate, were synthesized by Curtius rearrangement of the corresponding 5‐alkoxy‐1,3‐phenylene diacylazides. These diisocyanates were each polycondensed with three commercially available aromatic dianhydrides: 4,4′‐oxydiphthalic anhydride, 3,3′,4,4′‐(hexafluoroisopropylidene) diphthalic anhydride, and 3,3′,4,4′‐benzophenonetetracarboxylic dianhydride—in benzonitrile in the presence of 1,4‐diazabicyclo[2.2.2]octane as a catalyst to obtain a series of polyimides with inherent viscosities in the range 0.16–0.43 dL/g. Except for 3,3′,4,4′‐benzophenonetetracarboxylic dianhydride based polyimides, all of the polyimides were found to be soluble in dichloromethane, m‐cresol, 1‐methyl‐2‐pyrrolidinone, tetrachloroethane, and pyridine either at room temperature or on heating and could be cast into tough, flexible, transparent films from a solution in m‐cresol or tetrachloroethane. X‐ray diffractograms revealed that the polyimides with longer alkoxy chains had layered structures. The glass‐transition temperature of the polyimides containing pendent flexible alkoxy chains were in the range 159–246°C as measured by differential scanning calorimetry. The temperature for the 10% weight loss of the polyimides was in the range 410–460°C in a nitrogen atmosphere, which indicated good thermal stability. A pretilt angle of 2.97° was observed for the polyimide derived from 5‐octyloxy‐1,3‐phenylenediisocyanate and 4,4′‐oxydiphthalic anhydride. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Production of highly crosslinked microspheres by the precipitation polymerization of 2‐(diethylamino)ethyl methacrylate with two or three functional crosslinkers
Authors: Tunc Yeliz , Ulubayram Kezban 
Published: January 2009

AbstractPrecipitation polymerizations of 2‐(diethylamino)ethyl methacrylate were carried out with ethylene glycol dimethacrylate and then trimethylolpropane trimethacrylate in acetonitrile to produce monodisperse, highly crosslinked microspheres. Poly(diethylaminoethyl methacrylate‐co‐trimethylolpropane trimethacrylate) [poly(DEAEMA‐co‐TRIM)] microspheres, in the range of 1.2–2.7 μm, were obtained with a total monomer concentration of 1 vol % with respect to the solvent, and they kept their identity with several polymerization parameters. When the total monomer concentration was increased further, individual particles lost their identity and aggregated. Poly(DEAEMA‐co‐TRIM) particles with a total monomer concentration of 1 vol % had more discrete spherical forms with smoother surfaces, whereas in the poly(diethylaminoethyl methacrylate‐co‐ethylene glycol dimethacrylate) system, sticky microspheres were obtained with a total monomer concentration of 2.1 vol %. Moreover, several polymerization parameters were investigated to control the physical properties of microspheres of poly(DEAEMA‐co‐TRIM) and to understand the nature of the precipitation polymerization. Thus, the average particle size increased from 2.3 to 2.7 μm with an increased azobisisobutyronitrile concentration and then decreased to about 1.2 μm as the polymerization temperature was increased. All the microspheres produced under different polymerization conditions were found to be monodisperse (polydispersity index <0.1) with a narrow size distribution. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Tetrahydrosalen‐stabilized, chloride‐containing rare‐earth complexes: Facile initiator precursors for the preparation of hydroxytelechelic poly(ε‐caprolactone)s
Authors: Wu Guangming , Sun Weilin , Shen Zhiquan 
Published: January 2009

AbstractEnd‐capped poly(ε‐caprolactone)s (PCLs) have been prepared elsewhere by various initiators. However, hydroxytelechelic PCLs have been reported less frequently, although there are two hydroxyl end groups in one polymer chain, which allows diversified functionalization. Two tetrahydrosalen‐backboned chlorides containing rare‐earth complexes, YbLCl(DME)2 and ErLCl(DME) {where L is 6,6′‐[ethane‐1,2‐diylbis(methylazanediyl)]bis (methylene)bis(2,4‐di‐tert‐butylphenol) and DME is dimethoxyethane}, were first synthesized in this study, and they were used as initiator precursors for a ring‐opening polymerization in the presence of NaBH4 to afford hydroxytelechelic PCLs. The polymerization under different conditions was investigated, and a possible mechanism is proposed. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Bridging MCl Bonds with Ambiphilic Phosphine–Borane Ligands
Authors: Bontemps Sébastien , Bouhadir Ghenwa , Apperley David C. , Dyer Philip W. , Miqueu Karinne , Bourissou Didier 
Published: January 2009

AbstractBridging or pendant? Palladium and rhodium complexes deriving from an ambiphilic phosphine–borane ligand are shown to adopt a bridging P→MCl→B coordination mode in the solid state. DFT calculations provide more insight into the Cl→B interaction and suggest the possible interconversion of the bridging and B‐pendant forms in solution.magnified imageA combined experimental/theoretical study provides insight into the bridging coordination of MCl bonds with the ambiphilic phosphine–borane ligands iPr2P‐o(C6H4)‐BR2 (PBCy2: R=Cy; PBMes2: R=Mes). Reaction of [PdCl(allyl)(PBCy2)] (3) with HCl affords the related dinuclear complex [PdCl(μ‐Cl)(PBCy2)]2 (5). Subsequent cleavage of the chloride bridge by PPh3 leads to the heteroleptic mononuclear complex trans‐[PdCl2(PPh3)(PBCy2)] (6). The solid‐state structures of complexes 5 and 6 substantiate the propensity of the PBCy2 ligand to bridge Pd‐Cl bonds via P→PdCl→B interactions. DFT calculations carried out on both the model mononuclear complexes 3* and 6* reveal that in each system the energy of the linkage isomer with a Cl→B interaction is very similar to that without. A comparison of the solution and solid‐state 11B NMR spectroscopic data for complexes 3 and 6 suggests the possible interconversion of the bridging and B‐pendant forms in solution. Bridging coordination of the PBCy2 ligand across a RhCl bond is observed in the solid‐state structure of the related complex [RhCl(nbd)(PBCy2)] (7). Replacement of the Cy groups at boron by Mes substituents illustrates the role of steric factors on the participation of the Lewis acid upon coordination, no Cl→B interaction being observed in the complex [PdCl(allyl)(PBMes2)] (8).
New absolute magnitude calibrations for WUrsa Majoris type binaries
Authors: Eker Z. , Bilir S. , Yaz E. , Demircan O. , Helvacı M. 
Published: January 2009

AbstractParallaxes of W UMa stars in the Hipparcos catalogue have been analyzed. 31 W UMa stars, which have the most accurate parallaxes (σπ /π < 0.15) which are neither associated with a photometric tertiary nor with evidence of a visual companion, were selected for re‐calibrating the Period‐Luminosity‐Color (PLC) relation of W UMa stars. Using the Lutz‐Kelker (LK) bias corrected (most probable) parallaxes, periods (0.26 < P < 0.87, P in days), and colors (0.04 < (B – V)0 < 1.28) of the 31 selected W UMa, the PLC relation have been revised and re‐calibrated. The difference between the old (revised but not bias corrected) and the new (LK bias corrected) relations are almost negligible in predicting the distances of W UMa stars up to about 100 pc. But, it increases and may become intolerable as distances of stars increase. Additionally, using (J – H)0 and (H – Ks)0 colors from 2MASS (TwoMicron All Sky Survey) data, a PLC relation working with infrared data was derived. It can be used with infrared colors in the range –0.01 < (J – H)0 < 0.58, and –0.10 < (H – Ks)0 < 0.18. Despite of the fact that the 2MASS data refer to single epoch observations which are not guaranteed to be taken at maximum brightness of theWUMa stars, the established relation has been found surprisingly consistent and reliable in predicting LK corrected distances of W UMa stars (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Temporal behaviour of global perturbations in compressible axisymmetric flows with free boundaries
Authors: Zhuravlev V.V. , Shakura N.I. 
Published: January 2009

AbstractThe dynamics of small global perturbations in the form of a linear combination of a finite number of non‐axisymmetric eigenmodes is studied in the two‐dimensional approximation. The background flow is assumed to be an axisymmetric perfect fluid with adiabatic index γ = 5/3 rotating with a power law angular velocity distribution Γ ∝ r–q , 1.5 < q < 2.0, confined by free boundaries in the radial direction. The substantial transient growth of acoustic energy of optimized perturbations is discovered. An optimal energy growth G is calculated numerically for a variety of parameters. Its value depends essentially on the perturbation azimuthal wavenumber m and increases for higher values of m. The closer the rotation profile to the Keplerian law, the larger growth factors can be obtained but over a longer time. The highest acoustic energy increase found numerically is of order ∼102 over ∼6 typical Keplerian periods. Slow neutral eigenmodes with corotation radius beyond the outer boundary mostly contribute to the transient growth. The revealed linear temporal behaviour of perturbations may play an important role in angular momentum transfer in toroidal flows near compact relativistic objects (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
RoboNet‐II: Follow‐up observations of microlensing events with a robotic network of telescopes
Authors: Tsapras Y. , Street R. , Horne K. , Snodgrass C. , Dominik M. , Allan A. , Steele I. , Bramich D.M. , Saunders E.S. , Rattenbury N. , Mottram C. , Fraser S. , Clay N. , Burgdorf M. , Bode M. , Lister T.A. , Hawkins E. , Beaulieu J.P. , Fouqué P. , Albrow M. , Menzies J. , Cassan A. , Dominis‐Prester D. 
Published: January 2009

AbstractRoboNet‐II uses a global network of robotic telescopes to perform follow‐up observations of microlensing events in the Galactic Bulge. The current network consists of three 2 m telescopes located in Hawaii and Australia (owned by Las Cumbres Observatory) and the Canary Islands (owned by Liverpool John Moores University). In future years the network will be expanded by deploying clusters of 1 m telescopes in other suitable locations. A principal scientific aim of the RoboNet‐II project is the detection of cool extra‐solar planets by the method of gravitational microlensing. These detections will provide crucial constraints to models of planetary formation and orbital migration. RoboNet‐II acts in coordination with the PLANET microlensing follow‐up network and uses an optimization algorithm (“web‐PLOP”) to select the targets and a distributed scheduling paradigm (eSTAR) to execute the observations. Continuous automated assessment of the observations and anomaly detection is provided by the ARTEMiS system (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Dynamische Berechnung von Eisenbahnbrücken im Zuge von Hochgeschwindigkeitsstrecken – Ein alternatives Verfahren zur Simulation von Zugüberfahrten
Authors: Pircher Heinz , Stadler Christian , Glatzl Johann , Seitz Peter 
Published: January 2009

AbstractMit den neuen, EUROCODE‐gemäßen Normen werden auch baudynamische Berechnungen neu geregelt. Ein Berechnungsverfahren, einfacher und schneller anwendbar als die übliche Zeitschrittberechnung, wird für den Anwendungsfall “Dynamik von Eisenbahnbrücken im Zuge von Hochgeschwindigkeitsstrecken” gezeigt (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effektivität eines Erdbebenisolationssystems für Hochbauten mittels faserbewehrter Elastomerlager
Authors: Gerhaher Ulrich , Strauss Alfred , Bergmeister Konrad 
Published: January 2009

AbstractIn der hier vorgestellten Studie wird die Anwendbarkeit eines Erdbebenisolationssystems mittels faserbewehrter Elastomerlager für Hochbauten dargestellt. Ausgehend von im Wohn‐ und Bürobau üblichen Grundrissen werden Tragwerke mit drei bis zehn Geschossen bezüglich der Schnittgrößen aus Erdbebeneinfluss untersucht. Dabei wird aufgezeigt, in welchem Maße sich vor allem die zu verankernden Zugkräfte in den aussteifenden Wänden durch Einführung elastischer horizontaler Fugen reduzieren lassen. Die Effektivität verschiedener Fugenausführungen mit faserbewehrten Elastomerlagern wird diskutiert (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Berechnung dünnwandiger Stäbe mit offenem Querschnitt bei Beanspruchung durch Längskraft, zweiachsige Biegung und Torsion – ohne Bestimmung von Schwerpunkt, Schubmittelpunkt und Hauptachsen
Authors: Rubin Helmut 
Published: January 2009

AbstractFür einen allgemein beanspruchten, prismatischen Stab wird ein Berechnungskonzept gezeigt, bei dem die Beziehungen zwischen den Schnittgrößen und Verzerrungen des Stabelements nicht normiert, sondern in gekoppelter Form dargestellt werden. Dies bedeutet, dass der gesamten Berechnung ein beliebig wählbares Koordinatensystem y, z im Querschnitt zugrunde gelegt wird und dass Schwerpunkt, Schubmittelpunkt und Hauptachsen mit zugehörigen Querschnittsgrößen nicht bestimmt werden müssen.Auf Basis dieses Konzepts wird die Übertragungsbeziehung entwickelt, welche die vollständige Berechnung der Schnitt‐ und Verschiebungsgrößen eines beliebig gelagerten Stabes erlaubt. Schließlich lassen sich damit für beliebige Querschnittspunkte alle Normal‐ und Schubspannungen bestimmen (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Time‐domain power system simulator as an efficient tool for teaching and learning electric power quality phenomena
Authors: Santoso Surya 
Published: January 2009

AbstractElectric power quality (PQ) phenomena involve the interaction between various elements of the power system. Due to the complex nature of the phenomena, electric PQ education at the undergraduate level is challenging. The instructional method is typically based on the traditional descriptive‐inquiry approach. This article suggests that a time‐domain computer‐based simulation tool be used to supplement the traditional approach. The combined method allows students to simulate complex phenomena in a controlled environment so as to investigate the interaction between power system elements that give rise to the phenomena, and how the phenomena impact the system. The combined method is expected to reinforce and enhance the student learning process. The article then presents three simulation examples to demonstrate how the time‐domain simulation method can be integrated into the traditional descriptive‐inquiry method. © 2009 Wiley Periodicals, Inc. Comput Appl Eng Educ 17: 214–224, 2009; Published online in Wiley InterScience (www.interscience.wiley.com); DOI 10.1002/cae20194
A fully robust PARAFAC method for analyzing fluorescence data
Authors: Engelen Sanne , Frosch Stina , Jørgensen Bo Munk 
Published: January 2009

AbstractParallel factor analysis (PARAFAC) is a widespread method for modeling fluorescence data by means of an alternating least squares procedure. Consequently, the PARAFAC estimates are highly influenced by outlying excitation–emission landscapes (EEM) and element‐wise outliers, like for example Raman and Rayleigh scatter. Recently, a robust PARAFAC method that circumvents the harmful effects of outlying samples has been developed. For removing the scatter effects on the final PARAFAC model, different techniques exist. Newly, an automated scatter identification tool has been constructed. However, there still exists no robust method for handling fluorescence data encountering both outlying EEM landscapes and scatter. In this paper, we present an iterative algorithm where the robust PARAFAC method and the scatter identification tool are alternately performed. A fully automated robust PARAFAC method is obtained in that way. The method is assessed by means of simulations and a laboratory‐made data set. Copyright © 2009 John Wiley & Sons, Ltd.
Supramolecular Complexation of N‐Alkyl‐ and N,N′‐Dialkylpiperazines with Cucurbit[6]uril in Aqueous Solution and in the Solid State
Authors: Rekharsky Mikhail V. , Yamamura Hatsuo , Mori Tadashi , Sato Akihiro , Shiro Motoo , Lindeman Sergey V. , Rathore Rajendra , Shiba Kouhei , Ko Young Ho , Selvapalam Narayanan , Kim Kimoon , Inoue Yoshihisa 
Published: January 2009

AbstractWater seeds: Complex stoichiometry/composition and degree of oligomerization (oligomeric supramolecular complex formation) of cucurbit[6]uril (CB[6]) with N‐alkyl‐ and N,N′‐dialkylpiperazine were investigated in aqueous solutions by means of isothermal titration calorimetry (ITC), ESI‐MS, NMR and light scattering measurements.magnified imageComplex stoichiometry/composition and degree of oligomerization (oligomeric supramolecular complex formation) of cucurbit[6]uril (CB[6]) with N‐alkyl‐ and N,N′‐dialkylpiperazine were investigated in aqueous solutions by means of isothermal titration calorimetry (ITC), ESI‐MS, NMR and light scattering measurements. It was found that the complex stability and the degree of oligomerization increase with elongating the alkyl chain attached to the piperazine core. X‐ray crystallographic studies revealed a clear correlation between the structure of CB[6]–alkylpiperazine crystals obtained from aqueous solutions and the molecular weight/properties of host–guest oligomers existed in the solution as supramolecular “seeds” of crystal formation.