bluuebunny/crossref_metadata_2025_split huggingface dataset:
Wie werden Iminium‐katalysierte Cyclopropanierungen durch elektrostatische Aktivierung gesteuert?
Authors: Lakhdar Sami , Appel Roland , Mayr Herbert 
Published: June 2009

AbstractWieder gilt lg k=s(N+E): Im Gegensatz zu früheren Behauptungen reagieren einfache α,β‐ungesättigte Iminiumionen mit Schwefel‐Yliden. Elektrostatische Wechselwirkungen beschleunigen die Reaktion allerdings mehr als 105‐fach und sind für die hohe Stereoselektivität maßgebend.magnified image
Comparison of Cyanide and Carbon Monoxide as Ligands in Iron(II) Porphyrinates
Authors: Li Jianfeng , Noll Bruce C. , Schulz Charles E. , Scheidt W. Robert 
Published: June 2009

AbstractSehen Sie den Unterschied? Fünffach koordinierte Eisen(II)‐Cyanoporphyrinate zeigen Spin‐Crossover und können als Ausgangspunkt für die Synthese bislang unbekannter sechsfach koordinierter Komplexe dienen. Solche Bis(cyano)‐ und (Cyano)imidazol‐Komplexe werden vorgestellt, und die fünf‐ und sechsfach koordinierten (Cyano)eisen(II)‐Derivate werden mit ihren CO‐Analoga verglichen.magnified image
Hydrogen‐Bond‐Selective Phase Transfer of Nanoparticles across Liquid/Gel Interfaces
Authors: Mao Zhengwei , Guo Jinshan , Bai Shuo , Nguyen Tich‐Lam , Xia Haibing , Huang Yubin , Mulvaney Paul , Wang Dayang 
Published: June 2009

AbstractSchwimmunterricht: Kolloidale Nanopartikel mit Bürsten aus Polylactid (PLA, rot) und Poly(ethylenglycol) (PEG, schwarz) als Schale können über Flüssig‐flüssig‐ oder Flüssigkeits‐Gel‐Grenzflächen von einer organischen in eine wässrige Phase wechseln (siehe Bild: erster Schritt). Ursache ist die Zersetzung des PLA‐Überzugs und die Bildung von Wasserstoffbrücken zwischen den PEG‐Bürsten und der wässrigen Phase (zweiter Schritt).magnified image
Hochstabile Mikroblasen durch pH‐abhängige Aggregation oberflächenaktiver Teilchen
Authors: Drenckhan Wiebke 
Published: June 2009

AbstractExtrem monodisperse, mikroskalige Gasblasen lassen sich herstellen, indem CO2‐gefüllte Blasen in einem Mikrokanal in einer wässrigen Dispersion von Teilchen mitgeführt werden, deren Hydrophobie mit sinkendem pH‐Wert steigt. Innerhalb weniger Sekunden geht das in den Blasen enthaltene CO2 in Lösung, was den pH‐Wert der Dispersion senkt und damit die pH‐empfindlichen Teilchen an die Gas/flüssig‐Grenzfläche treibt (siehe Bild). Dort bilden sie eine Art festen „Schutzpanzer“, der die Blase vor weiterem Schrumpfen schützt.magnified image
Magnetic Bistability of Individual Single‐Molecule Magnets Grafted on Single‐Wall Carbon Nanotubes
Authors: Giusti Anna , Charron Gaëlle , Mazerat Sandra , Compain Jean‐Daniel , Mialane Pierre , Dolbecq Anne , Rivière Eric , Wernsdorfer Wolfgang , Ngo Biboum Rosa , Keita Bineta , Nadjo Louis , Filoramo Arianna , Bourgoin Jean‐Philippe , Mallah Talal 
Published: June 2009

AbstractEinzelmolekülmagnete aus sechskernigem FeIII‐Polyoxometallat (siehe Struktur) können nichtkovalent auf der Oberfläche von einwandigen Kohlenstoffnanoröhren angeordnet werden. Sich ergänzende Charakterisierungsmethoden (siehe TEM‐Bild und magnetische Hystereseschleifen) belegen die Integrität und Bistabilität der einzelnen Moleküle, die für den Aufbau von Einzelmolekül‐Speichereinheiten genutzt werden könnten.magnified image
Dynamic Nuclear Polarization with a Rigid Biradical
Authors: Matsuki Yoh , Maly Thorsten , Ouari Olivier , Karoui Hakim , Le Moigne François , Rizzato Egon , Lyubenova Sevdalina , Herzfeld Judith , Prisner Thomas , Tordo Paul , Griffin Robert G. 
Published: June 2009

AbstractA new polarizing agentwith superior performance in dynamic nuclear polarization experiments is introduced, and utilizes two TEMPO (2,2,6,6‐tetramethylpiperidine‐1‐oxyl) moieties connected through a rigid spiro tether (see structure). The observed NMR signal intensities were enhanced by a factor of 1.4 compared to those of TOTAPOL, a previously described TEMPO‐based biradical with a flexible tether.magnified image
A Soft Alternative to the Dominant {(C5Me5)2U} Motif
Authors: Ephritikhine Michel 
Published: June 2009

AbstractPincers do something for U that sandwiches don′t: The dead‐ends in the metallocene chemistry of the actinides can be circumvented by using a soft PNP pincer ligand (see scheme). The PNP ligand has been shown to be flexible, hemilabile, and capable of stabilizing low‐ and high‐valent uranium species. The bis(PNP) framework is a valuable alternative to the (C5Me5)2 ligand set, offering distinct structures and reaction patterns.magnified image
Hydrogen‐Bond‐Selective Phase Transfer of Nanoparticles across Liquid/Gel Interfaces
Authors: Mao Zhengwei , Guo Jinshan , Bai Shuo , Nguyen Tich‐Lam , Xia Haibing , Huang Yubin , Mulvaney Paul , Wang Dayang 
Published: June 2009

AbstractIn the swim: Colloidal nanoparticles coated with polylactide (PLA, red) and poly(ethylene glycol) brushes (PEG, black) can transfer from organic to aqueous phases across liquid/liquid or liquid/gel interfaces during degradation of the PLA coating (see picture: first step), which is driven selectively by the hydrogen bonding of the PEG coating with the aqueous phase (second step).magnified image
Generation of Superstable, Monodisperse Microbubbles Using a pH‐Driven Assembly of Surface‐Active Particles
Authors: Drenckhan Wiebke 
Published: June 2009

AbstractBubbling to the surface: Microscale gas bubbles can be generated in a microfluidic device by simultaneously injecting CO2 and a dispersion of particles whose hydrophobicity increases as the pH value decreases. The CO2 dissolves rapidly out of the bubbles, which shrink, and render the dispersion increasingly acidic. This drives the particles to the bubble surface where they form a type of “armor” against further dissolution (see picture).magnified image
Ketone Hydrosilylation with Sugar Silanes Followed by Intramolecular Aglycone Delivery: An Orthogonal Glycosylation Strategy
Authors: Buchan Zachary A. , Bader Scott J. , Montgomery John 
Published: June 2009

AbstractGettin' a little sugar—no alcohol required: A procedure for the direct glycosylation of ketones without a hydroxy intermediate enables the site‐selective glycosylation of hydroxyketones at the ketone or the alcohol functionality without the use of protecting groups on the aglycone (see scheme). Site selectivity is controlled by the catalyst structure in hydrosilylation and dehydrogenative silylation reactions with sugar silanes. Bn=benzyl.magnified image
The effect of heat history on thermal degradation of elastomers containing butadiene units
Authors: Amiri Amraee I. 
Published: June 2009

AbstractThe aim of this research is to develop a new method for studying thermal degradation behavior of elastomers containing butadiene units by isothermal and anisothermal analysis. Accelerated aging such as isothermal thermogravimetry analysis shows that when BR, SBR and NBR elastomers are subjected to specific time and temperature condition in nitrogen atmosphere, an interchain reaction occurs. Experimental observations also show that thermal degradation mechanism of these elastomers depends on heating rate and time–temperature history. For these types of elastomers, the effect of time is similar to temperature and time–temperature superposition principle can be employed for studying the thermal degradation mechanism of elastomer containing butadiene units. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Synthesis and characterization of new soluble and thermally stable poly(amide‐imide)s containing pendent benzimidazole moieties
Authors: Toiserkani Hojjat , Saidi Kazem , Sheibani Hassan 
Published: June 2009

AbstractPreparation of new types of poly(amide‐imide)s with high thermal stability and improved solubility was investigated. Two new diimide‐dicarboxylic acid containing pendent benzimidazole group, viz., 2‐[3,5‐bis(N‐trimellitimidoyl)‐phenyl] benzimidazole (DIDA‐i) and 2‐[3,5‐bis(N‐trimellitimidoyl)‐phenyl] 5‐methyl benzimidazole (DIDA‐ii) from the condensation of 5‐(2‐benzimidazole)‐1,3‐phenylenediamine (DABIA) and 5‐(5‐methyl‐2‐benzimidazole)‐1,3‐phenylenediamine (DABIB) with trimellitic anhydride in glacial acetic acid were synthesized, respectively. 1,3‐bis(N‐trimellitimidoyl)benzene (DIDA‐iii, as a reference) was also synthesized in a similar manner to study the properties of the its structure. Three series of aromatic poly(amide‐imide)s were prepared by triphenyl phosphite‐activated polycondensation from diimide‐dicarboxylic acid DIDA‐i, DIDA‐ii, and the reference monomer DIDA‐iii with various aromatic diamines. The polymers were obtained in quantitative yields with inherent viscosities between 0.46 and 0.81 dL g−1. The effects of the benzimidazole pendent groups on the polymer properties, such as solubility and thermal stability were investigated by comparison of the polymers. The polymers bearing benzimidazole pendent groups exhibited thermal stability and good solubility in common polar solvents higher than the reference polymers. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Oriented Growth of Small Mesochannels Utilizing a Porous Anodic Alumina Substrate: Preparation of Continuous Film with Standing Mesochannels
Authors: Yamauchi Yusuke , Nagaura Tomota , Inoue Satoru 
Published: June 2009

AbstractStanding mesochannels: An “oriented growth on the mesoscale” is demonstrated for the formation of standing mesochannels. The standing mesochannels in the continuous film grow epitaxially from the mesochannels oriented along the straight holes of porous anodic alumina substrate.magnified image
Spannglieder mit Kunststoffhüllrohren zur Herstellung von Brücken ohne Betonstahlbewehrung
Authors: Berger Johannes , Kollegger Johann 
Published: June 2009

AbstractBei Brückentragwerken aus Beton weist die konventionelle Abdichtung in der Praxis häufig keine zufriedenstellende Gebrauchsdauer auf. Fehlerhafte Abdichtungen führen zu Chlorideintrag in das Tragwerk durch Biegerisse an der Brückenoberseite im Bereich negativer Momente. Bei Durchfahrten unter Brücken besteht die Gefahr des Chlorideintrags durch Salznebel, welcher sich an allen Außenflächen der Brücke anlegt. Neben der Sanierungsanfälligkeit der Abdichtung stellt der Fahrbahnbelag ebenfalls ein Verschleißteil dar. Beide müssen in regelmäßigen Abständen erneuert werden, was neben der Beeinträchtigung des Verkehrs auch hohe Kosten verursacht. Die in diesem Aufsatz vorgestellte Methode ist dadurch gekennzeichnet, dass keine korrosionsempfindliche Bewehrung verwendet und der Fahrbahnbelag in das Tragwerk integriert wird. Das Ziel besteht darin, Betonbrücken zu schaffen, die gegenüber den bekannten Ausführungen eine verbesserte Dauerhaftigkeit aufweisen und mit vergleichbarem Kostenaufwand hergestellt werden können. Die Ergebnisse von experimentellen Untersuchungen zum Tragverhalten solcher Tragstrukturen werden vorgestellt.
Ingenieurbaukunst: Die Anfänge des Spannbetonbaus
Authors: Kleinmanns Joachim , Weber Christiane 
Published: June 2009

AbstractDer weltbekannte Bauingenieur Fritz Leonhardt wäre am 11. Juli 2009 hundert Jahre alt geworden. In der Öffentlichkeit ist er vor allem als “Vater” des Stuttgarter Fernsehturms bekannt. Er selbst sah sich jedoch in erster Linie als Brückenbauer, auch wenn ihm seine Türme gleichermaßen weltweit Anerkennung eingebracht hatten.An dieser Stelle wird seine Leistung auf dem Gebiet des Spannbetonbaus gewürdigt, mit dem er sich seit 1944 intensiv beschäftigte. Behandelt werden seine frühen Spannbetonbrücken und ‐türme. Für Fachleute, insbesondere Bauingenieure, war und ist Fritz Leonhardt der “Spannbeton‐Papst”, ein Ruf, der sich in Leonhardts wissenschaftlichen und anwendungsbezogenen Leistungen für den Spannbetonbau begründet. Leonhardts technische Kunstfertigkeit und seine unermüdliche, auch auf seine Mitarbeiter übertragene Suche nach optimierten Lösungen führten zu zahlreichen Innovationen auf diesem Gebiet. Dabei war Leonhardt stets die praktische Anwendung der Forschungsergebnisse wichtig.Eine umfassende Publikation zu Leben und Werk Fritz Leonhardts, herausgegeben von den Autoren dieses Beitrags, ist gerade aus Anlass des hundertsten Geburtstags erschienen.
Predation between prokaryotes and the origin of eukaryotes
Authors: Davidov Yaacov , Jurkevitch Edouard 
Published: June 2009

AbstractAccumulating data suggest that the eukaryotic cell originated from a merger of two prokaryotes, an archaeal host and a bacterial endosymbiont. However, since prokaryotes are unable to perform phagocytosis, the means by which the endosymbiont entered its host is an enigma. We suggest that a predatory or parasitic interaction between prokaryotes provides a reasonable explanation for this conundrum. According to the model presented here, the host in this interaction was an anaerobic archaeon with a periplasm‐like space. The predator was a small (facultative) aerobic α‐proteobacterium, which penetrated and replicated within the host periplasm, and later became the mitochondria. Plausible conditions under which this interaction took place and circumstances that may have led to the contemporary complex eukaryotic cell are discussed.
Structure brings clarity: Structured illumination microscopy in cell biology
Authors: Langhorst Matthias F. , Schaffer Joerg , Goetze Bernhard 
Published: June 2009

AbstractBiological samples are three dimensional and, therefore, optical sectioning is mandatory for microscopic images to precisely show the localization or function of structures within biological samples. Today, researchers can choose from a variety of methods to obtain optical sections. This article focuses on structured illumination microscopy, which is a group of techniques utilizing a combination of optics and mathematics to obtain optical sections: A structure is imaged onto the sample by optical means and the additional information thereby encoded in the image is used to calculate an optical section from several acquired images. Different methods of structured illumination microscopy (mainly grid projection and aperture correlation) are discussed from a practical point of view, concentrating on advantages, limitations and future prospects of these techniques and their use in cell biology. Structured illumination can also be used to obtain super‐resolution information if structures of higher frequency are projected onto the sample. This promising approach to super‐resolution microscopy is also briefly discussed from a user's perspective.
Going live: A comparative analysis of the suitability of the RFP derivatives RedStar, mCherry and tdTomato for intravital and in vitro live imaging of Plasmodium parasites
Authors: Graewe Stefanie , Retzlaff Silke , Struck Nicole , Janse Chris J. , Heussler Volker T. 
Published: June 2009

AbstractFluorescent proteins have proven to be important tools for in vitro live imaging of parasites and for imaging of parasites within the living host by intravital microscopy. We observed that a red fluorescent transgenic malaria parasite of rodents, Plasmodium berghei‐RedStar, is suitable for in vitro live imaging experiments but bleaches rapidly upon illumination in intravital imaging experiments using mice. We have therefore generated two additional transgenic parasite lines expressing the novel red fluorescent proteins tdTomato and mCherry, which have been reported to be much more photostable than first‐ and second‐generation red fluorescent proteins including RedStar. We have compared all three red fluorescent parasite lines for their use in in vitro live and intravital imaging of P. berghei blood and liver parasite stages, using both confocal and wide‐field microscopy. While tdTomato bleached almost as rapidly as RedStar, mCherry showed improved photostability and was bright in all experiments performed.
Glioblastoma targeting via integrins is concentration dependent
Authors: Rosca Elena V. , Gillies Robert J. , Caplan Michael R. 
Published: June 2009

AbstractA novel approach to treat cancer more selectively is achieved by targeting drugs to cells via conjugating the drug or imaging agent to an antibody or ligand for a cell surface receptor that is over‐expressed by the target cell population. Previous work by us has suggested that enhanced specificity can be obtained by multivalency of binding moieties. In this study we investigated the binding specificity of a multivalent construct including three peptides segments (TWYKIAFQRNRK), which bind the α6β1‐integrin, linked by poly(ethylene glycol) spacers. The binding specificity of the constructs was calculated by quantifying their binding to target cells (glioma cells, SF 767) relative to non‐targeted cells (normal human astrocytes, NHA). Dodecapeptide constructs (monovalent) exhibit specificity equal to the ratio of receptor expression at all concentrations. However, trivalent constructs demonstrated a sharp increase in specificity at concentrations less than the affinity of the receptor–ligand bond (4.28 µM). These experiments (conducted at 4°C) were consistent with the theoretical prediction and indicate that the biophysical model captures the basic trend of the data in the absence of receptor internalization, although the concentration at which increased specificity is observed is greater than predicted. The biophysical model does not predict the results of 37°C experiments, and this is shown to be due to internalization which occurs at 37°C but not at 4°C. Biotechnol. Bioeng. 2009; 104: 408–417 © 2009 Wiley Periodicals, Inc.
A practical approach for exploration and modeling of the design space of a bacterial vaccine cultivation process
Authors: Streefland M. , Van Herpen P.F.G. , Van de Waterbeemd B. , Van der Pol L.A. , Beuvery E.C. , Tramper J. , Martens D.E. , Toft M. 
Published: June 2009

AbstractA licensed pharmaceutical process is required to be executed within the validated ranges throughout the lifetime of product manufacturing. Changes to the process, especially for processes involving biological products, usually require the manufacturer to demonstrate that the safety and efficacy of the product remains unchanged by new or additional clinical testing. Recent changes in the regulations for pharmaceutical processing allow broader ranges of process settings to be submitted for regulatory approval, the so‐called process design space, which means that a manufacturer can optimize his process within the submitted ranges after the product has entered the market, which allows flexible processes. In this article, the applicability of this concept of the process design space is investigated for the cultivation process step for a vaccine against whooping cough disease. An experimental design (DoE) is applied to investigate the ranges of critical process parameters that still result in a product that meets specifications. The on‐line process data, including near infrared spectroscopy, are used to build a descriptive model of the processes used in the experimental design. Finally, the data of all processes are integrated in a multivariate batch monitoring model that represents the investigated process design space. This article demonstrates how the general principles of PAT and process design space can be applied for an undefined biological product such as a whole cell vaccine. The approach chosen for model development described here, allows on line monitoring and control of cultivation batches in order to assure in real time that a process is running within the process design space. Biotechnol. Bioeng. 2009; 104: 492–504 © 2009 Wiley Periodicals, Inc.
Evaluation of monoclonal antibody and phenolic extraction from transgenic Lemna for purification process development
Authors: Woodard Susan L. , Wilken Lisa R. , Barros Georgia O.F. , White Steven G. , Nikolov Zivko L. 
Published: June 2009

AbstractSeveral pharmaceutical protein products made in transgenic plant hosts are advancing through clinical trials. Plant hosts present a different set of impurities from which the proteins must be purified compared to other expression hosts such as mammalian cells. In this work, phenolic compounds present in extracts of monoclonal antibody (mAb)‐expressing Lemna minor were examined. Two different extraction pHs were evaluated to assess the effect of extraction condition on the concentration of mAb and phenolics in the extracts. The extract prepared at pH 4.5 had an enriched level of mAb relative to native protein when compared to a pH 7.5 extract although similar overall mAb was extracted at either pH. Slightly more mAb was recovered from the pH 3 elution of the pH 4.5 extract run on a MabSelect column than was recovered from the pH 7.5 extract. Phenolic levels in extracts were assessed by spectrophotometry, Folin–Ciocalteu assay and by profiling on RP‐HPLC. The Folin–Ciocalteu assay results did not agree with those obtained by the other two methods. Therefore phenolic levels were quantified by RP‐HPLC comparing the total area of phenolic peaks to those of reference phenolic compounds. The pH 7.5 extract had 22% less phenolics than the pH 4.5 extract. Acidic precipitation of the pH 7.5 extract resulted in further reduction of phenolics originally present in the pH 7.5 extract. The total phenolics present in the extracts were effectively removed by incubation of extracts with a commercially available anion exchange resin, Amberlite IRA‐402. We anticipate that early removal of phenolic compounds will prolong the life of more expensive affinity columns used for the purification of potential pharmaceutical proteins and should therefore be considered in process development involving proteins extracted from transgenic plant hosts. Biotechnol. Bioeng. 2009; 104: 562–571 © 2009 Wiley Periodicals, Inc.
Children's nurses' experiences of child protection: what helps?
Authors: Rowse Vicki 
Published: June 2009

AbstractThis paper reports on one area of findings of a study undertaken in the spring of 2008 at a district general hospital in the south of England. Individual semi‐structured interviews using an interpretive phenomenological approach were undertaken with 15 nurses and midwives working in paediatrics who had been involved in child protection cases. The aim was to explore their views and feelings of the experience. Very little research was found to inform this subject and none specifically with nurses working with sick children. Interviews were taped, transcribed and analysed thematically. It was discovered that involvement in child protection has a lasting impact on individuals; nurses need procedural information from a knowledgeable supporter during a case; and they need support from the right person in the right place at the right time for them. The Named Nurse was identified as being crucial in giving effective support to individuals during child protection cases and trusted advice and support helps staff follow through on niggling concerns, potentially preventing abuse. Copyright © 2009 John Wiley & Sons, Ltd.
Fast EMG‐data driven skin deformation
Authors: Kasap Mustafa , Chaudhuri Parag , Magnenat‐Thalmann Nadia 
Published: June 2009

AbstractVirtual characters are being modeled and animated with increasing accuracy and photorealism in current games and virtual reality simulations. However, the detailed modeling of dynamic skin deformations due to movement of the muscles during articulation is still prohibitively expensive for real‐time simulations. We present in this paper a fast approach for modeling such deformations driven by Electromyography (EMG) data. We demonstrate the method on the muscles of the upper leg during a gait cycle. A muscle map, created from a 3D muscle model, is applied as a deformation map to deform the skin surface as per the underlying muscle geometry. EMG signals recorded from a gait cycle are then used to dynamically vary the weights in the deformation map during animation thus producing the dynamic skin deformations. The whole operation is done on the GPU to make it very fast and suitable forreal‐time simulations. Copyright © 2009 John Wiley & Sons, Ltd.