bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nanoscale Chemical Imaging of the Reduction Behavior of a Single Catalyst Particle
Authors: de Smit Emiel , Swart Ingmar , Creemer J. Fredrik , Karunakaran Chithra , Bertwistle Drew , Zandbergen Henny W. , de Groot Frank M. F. , Weckhuysen Bert M. 
Published: February 2009

AbstractA closer look: Investigation of the reduction properties of a single Fischer–Tropsch catalyst particle, using in situ scanning transmission X‐ray microscopy with spatial resolution of 35 nm, reveals a heterogeneous distribution of Fe0, Fe2+, and Fe3+ species. Regions of different reduction properties are defined and explained on the basis of local chemical interactions and catalyst morphology.magnified image
Self‐Assembly Made Durable: Water‐Repellent Materials Formed by Cross‐Linking Fullerene Derivatives
Authors: Wang Jiaobing , Shen Yanfei , Kessel Stefanie , Fernandes Paulo , Yoshida Kaname , Yagai Shiki , Kurth Dirk G. , Möhwald Helmuth , Nakanishi Takashi 
Published: February 2009

AbstractFullerene flakes: A diacetylene‐functionalized fullerene derivative self‐organizes into flakelike microparticles (see picture). Both the diacetylene and C60 moieties can be effectively cross‐linked, which leads to supramolecular materials with remarkable resistivity to solvent, heat, and mechanical stress. Moreover, the surface of the cross‐linked flakelike objects is highly durable and water‐repellent.magnified image
Inside Cover: Synthesis, Structure, and Complexation Properties of Partially and Completely Reduced meso‐Octamethylporphyrinogens (Calix[4]pyrroles) (Angew. Chem. Int. Ed. 9/2009)
Authors: Blangy Valeria , Heiss Christoph , Khlebnikov Vsevolod , Letondor Christophe , Stoeckli‐Evans Helen , Neier Reinhard 
Published: February 2009

AbstractCalix[4]pyrrole is a beautiful, easy‐to‐synthesize macrocycle that completely changes its properties upon reduction and has been known for more than 120 years thanks to the work of Adolf von Baeyer. Its reduced form is described for the first time by H. Stoeckli‐Evans, R. Neier and co‐workers in their Communication on page 1688 ff. Metal complexes can be formed with great ease, thus creating an array of four directed hydrogen bonds.magnified image
A Recombinant Fragment of Human Surfactant Protein D Lacking the Short Collagen‐Like Stalk Fails to Correct Morphological Alterations in Lungs of SP‐D Deficient Mice
Authors: Knudsen Lars , Wucherpfennig Katharina , Mackay Rose‐Marie , Townsend Paul , Mühlfeld Christian , Richter Joachim , Hawgood Samuel , Reid Kenneth , Clark Howard , Ochs Matthias 
Published: February 2009

AbstractEmphysema‐like pathology is a characteristic feature of surfactant protein D (SP‐D) knock‐out mice. Treatment with a recombinant fragment of human SP‐D consisting of a short collagen‐like stalk (but not the entire collagen‐like domain of native SP‐D), neck, and carbohydrate recognizing domain (CRD) inhibits development of emphysema‐like pathology in SP‐D deficient mice. On the other hand, it has been shown that the entire collagen‐like domain is necessary for preventing SP‐D knock‐out mice from pulmonary emphysema development. Thus, in the present study, we aimed to elucidate the role of the short collagen‐like stalk for the function of the recombinant fragment of human SP‐D. We treated SP‐D knock‐out mice with a fragment of human SP‐D lacking the short collagen‐like stalk and compared the effects on lung morphology with results from untreated wild‐type and SP‐D knock‐out mice and from SP‐D knock‐out mice treated with a recombinant fragment of human SP‐D including the short collagen‐like stalk. The fragment of SP‐D lacking the short collagen‐like stalk failed to correct pulmonary emphysematous alterations demonstrating the importance of the short collagen‐like stalk for the biological activity of the recombinant fragment of human SP‐D. Anat Rec, 2009. © 2008 Wiley‐Liss, Inc.
Das städtische Mikroklima: Analyse für die Stadt‐ und Gebäudeplanung
Authors: Katzschner Lutz , Maas Anton , Schneider Andrea 
Published: February 2009

AbstractVor dem Hintergrund einer globalen Klimaerwärmung wird auch in der Stadt‐ und Gebäudeplanung die zunehmende Bedeutung des Mikroklimas im Hinblick auf den thermischen Komfort im Außen‐ und Innenraum sowie auf die Energieaufwendungen für Raumkonditionierung erkannt. Zur besseren Berücksichtigung dieses Aspektes in der Stadtplanung werden neben qualitativen vor allem quantitative Bewertungsverfahren benötigt. Globale Klimaveränderungen bewirken eine Intensivierung der städtischen Wärmeinsel und des Hitzestresses. In ausgewählten Stadtquartieren in Kassel wurden Untersuchungen zum thermischen Komfort in Außenräumen durchgeführt. Sie bestehen aus experimentellen Untersuchungen einschließlich von Befragungen zur Nutzung von urbanen Freiräumen und zum thermischen Empfinden sowie numerischen Simulationsberechnungen zur thermischen Belastung unter der Annahme der derzeitigen und zukünftigen regionalen Klimabedingungen. Die thermischen Bedingungen im Außenraum setzen sich im Gebäudeinnern fort, eine Verknüpfung der Innen‐ und Außenklimabetrachtungen muss daher erfolgen. Ziel einer Forschungsarbeit an der Universität Kassel ist die Untersuchung und Darstellung verschiedener Mikroklimate und ihres Einflusses auf das thermische Gebäudeverhalten (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Einfluss der vom menschlichen Körper absorbierten Solarstrahlung für das Wärmeempfinden in Gebäuden
Authors: Otto Frank 
Published: February 2009

AbstractDas nachhaltige Bauen hat u. a. das Wohlbefinden des Menschen im Blick, das wesentlich vom Raumklima beeinflusst wird. Von zentraler Bedeutung für ein hohes Maß an Zufriedenheit mit der Umgebung ist thermische Behaglichkeit. Es ist zu erwarten, dass die Solarstrahlung vor allen Dingen in den Wintermonaten aufgrund der dominierenden diffusen Strahlung einen günstigen Einfluss auf Aufenthaltsräume hat. Hingegen kann eine direkte Besonnung im Sommer oder an strahlungsreichen Wintertagen in Fensternähe schnell zu unbehaglichen Zuständen führen, denen durch entsprechende Sonnenschutzmaßnahmen entgegengewirkt werden muss. Die Bedeutung der Solarstrahlung für das Wärmeempfinden wird auf der Grundlage einer Weiterentwicklung des Fanger schen Ansatzes anhand von Simulationsrechnungen aufgezeigt. Im Beitrag werden die wesentlichen Ergebnisse zusammengefasst (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Methoden zum Einsatz diskreter, webbasierter Wetterprognosen in Gebäudetechnik und Lastmanagement
Authors: Seerig Axel , Sagerschnig Carina 
Published: February 2009

AbstractPrognosegeführte Regelungen verwenden zumeist kostenpflichtige stündliche Wetterprognosen, die auf der momentan gemessenen Außentemperatur basieren (z. B. Verschiebemethode) oder stündliche Prognosen eines nationalen meteorologischen Dienstes für den jeweiligen Standort. Mit Hilfe der prognostizierten Werte werden unter Verwendung geeigneter Modelle die jeweils benötigten Lastgänge vorausberechnet und weiterverarbeitet.Das Internet hingegen bietet die Möglichkeit, von vielen Anbietern kostenfrei Wetterprognosen für beliebige Standorte zu erhalten. Gewöhnlich sind diese Prognosen zumindest für die maximale und minimale Außentemperatur für fünf bis maximal neun Tage im Voraus verfügbar. Für die meisten Anwendungen in der Gebäude‐ und Energietechnik werden jedoch Werte in stündlicher bzw. viertelstündlicher Auflösung benötigt. Gegenstand dieses Aufsatzes ist die Beschreibung eines Verfahrens zur Erstellung von zeitlich beliebig aufgelösten Wetterdaten auf Basis von frei verfügbaren Wetterprognosen aus dem Internet. Als Beispiele für den Einsatz der darauf basierenden prognosegeführten Regelung werden die Beladung eines Eisspeichers sowie die Lastprognose eines Gebäudes bzw. einer Liegenschaft besprochen (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Gekoppelte Simulation zur Spezifikation von Heiz‐ und Kühlkörpern
Authors: Gritzki Ralf , Perschk Alf , Richter Wolfgang , Rösler Markus 
Published: February 2009

AbstractModerne Gebäude‐ und Raumkonzepte verlangen oft ein Umdenken gegenüber herkömmlichen Lösungen zur Heizung oder auch Kühlung der Gebäude. Oft ist jedoch nicht quantifizierbar, ob neue Ideen wirklich umsetzbar sind, da vereinfachte Abschätzungen eine zu große Unschärfe besitzen. Deshalb wurde ein von den Autoren maßgeblich entwickeltes und erfolgreich eingesetztes Programmsystem zur gekoppelten Gebäude‐, Anlagen‐ und Raumluftströmungssimulation mit einem weiteren räumlich und zeitlich hoch aufgelösten Modell für die Heiz‐ und Kühlkörpersimulation gekoppelt. Auf diese Weise können nicht nur Prüfszenarien aus der Heizungstechnik nachgebildet, sondern auch spezielle Betriebsverhältnisse oder Kühlkörper zur Raumtemperierung untersucht werden. Die Ansätze für die Modellierung sind kurz erläutert, ausgewählte Ergebnisse werden vorgestellt und diskutiert (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Effect of human patient plasma ex vivo treatment on gene expression and progenitor cell activation of primary human liver cells in multi‐compartment 3D perfusion bioreactors for extra‐corporeal liver support
Authors: Schmelzer Eva , Mutig Kerim , Schrade Petra , Bachmann Sebastian , Gerlach Jörg C , Zeilinger Katrin 
Published: February 2009

AbstractCultivation of primary human liver cells in innovative 3D perfusion multi‐compartment capillary membrane bioreactors using decentralized mass exchange and integral oxygenation provides in vitro conditions close to the physiologic environment in vivo. While a few scale‐up bioreactors were used clinically, inoculated liver progenitors in these bioreactors were not investigated. Therefore, we characterized regenerative processes and expression patterns of auto‐ and paracrine mediators involved in liver regeneration in bioreactors after patient treatment. Primary human liver cells containing parenchymal and non‐parenchymal cells co‐cultivated in bioreactors were used for clinical extra‐corporeal liver support to bridge to liver transplantation. 3D tissue re‐structuring in bioreactors was studied; expression of proteins and genes related to regenerative processes and hepatic progenitors was analyzed. Formation of multiple bile ductular networks and colonies of putative progenitors were observed within parenchymal cell aggregates. HGF was detected in scattered cells located close to vascular‐like structures, expression of HGFA and c‐Met was assigned to biliary cells and hepatocytes. Increased expression of genes associated to hepatic progenitors was detected following clinical application. The results confirm auto‐ and paracrine interactions between co‐cultured cells in the bioreactor. The 3D bioreactor provides a valuable tool to study mechanisms of progenitor activation and hepatic regeneration ex vivo under patient plasma treatment. Biotechnol. Bioeng. 2009;103: 817–827. © 2009 Wiley Periodicals, Inc.
Gedanken zum Schutz der biologischen Vielfalt. Globales Unwissen contra Biodiversität
Authors: Wirth Roland , Glaw Frank 
Published: February 2009

AbstractKompetenter Biodiversitätsschutz setzt ausreichendes Wissen voraus, doch nicht einmal die Zahl der auf der Erde vorkommenden Arten ist annähernd bekannt. Über deren Bedrohungsstatus wissen wir noch viel weniger. Die Ursachen für die Bedrohung der Biodiversität sind vielfältig. Neben den Kernproblemen wie Bevölkerungswachstum und steigendem Ressourcenverbrauch wird erfolgreicher Biodiversitätsschutz auch durch einen Mangel an Taxonomen und Ökologen, Bürokratie, Politik und Fehlinterpretationen von Fakten behindert. Um die eklatanten Wissensdefizite abzubauen, müssen die Erfassung und der Schutz der Biodiversität viel stärker als globale Herausforderung begriffen und entsprechend finanziert werden.
Winkerkrabben: Bluff mit großer Schere
Authors: Wendler Silke 
Published: February 2009

AbstractDie Männchen vieler Tierarten nutzen stark ausgeprägte sekundäre Geschlechtsmerkmale bei der Werbung um Weibchen ebenso wie beim Kräftemessen mit Rivalen. So auch die Winkerkrabben, deren Männchen eine extrem vergrößerte Schere haben. Geht bei einem Kampf eine Schere verloren, wächst diese vollständig nach. Männchen der Krabbenart Uca mjoebergi bilden allerdings eine nahezu funktionslose Schere nach und täuschen damit ihre Artgenossen.
Evolution Megalab: Die geheimnisvolle Vielfalt der Bänderschnecken
Authors: Anton Christian , Bossdorf Oliver 
Published: February 2009

AbstractInnerartliche Variation ist eines der Schlüsselprinzipien der Evolution. Ein Paradebeispiel sind die Gehäuse der Schwarzmündigen Bänderschnecke (Cepaea nemoralis), deren extreme Farb‐ und Bänderungsvielfalt mit natürlicher Selektion durch Fraßfeinde und anderen Umweltbedingungen zusammenhängt. In einem europaweiten Projekt wollen Evolutionsbiologen nun herausfinden, wie die Verbreitung und Vielfalt der Bänderschnecke durch die aktuelle Klimaerwärmung beeinflusst wird.
ELISA – Tipps und Tricks zur Durchführung
Authors: Schrödel Andrea 
Published: February 2009

AbstractDiejenigen unter Ihnen, die schon ELISA‐Tests im Labor durchführen, werden sich häufiger den Kopf über nicht reproduzierbare Werte und falsch positive Signale zerbrochen haben. Nachfolgende Tipps sollen versuchen, den Ursachen dieser Phänomene auf den Grund zu kommen.
Structurally Refined β‐Lactones as Potent Inhibitors of Devastating Bacterial Virulence Factors
Authors: Böttcher Thomas , Sieber Stephan A. 
Published: February 2009

AbstractDisarmed forces: Inhibition of the central virulence regulator ClpP by structurally refined β‐lactones resulted in dramatically reduced production of devastating virulence factors, including pyrogenic toxin superantigens derived from pathogenic multiresistant Staphylococcus aureus strains. Targeting of this virulence regulator could present an attractive strategy for neutralizing the harmful effects of bacterial pathogens, and help the host immune response to eliminate the disarmed bacteria.magnified image
Mass Transport in Multilayer Porous Metallic Membranes – Diagnosis, Identification and Validation
Authors: Edreva V. , Zhang F. , Mangold M. , Tsotsas E. 
Published: February 2009

AbstractFor a reliable description of mass transfer in membrane reactors the multilayer structure of the membrane is essential. This paper discusses methods which are sufficient to distinguish between homogeneous and composite membranes, and some others which are not. Different mass transport experiments (single gas permeation, isobaric diffusion, transient diffusion) with a porous metallic membrane consisting of two layers and the dusty gas model were used for this purpose. Simultaneous identification of mass transport parameters of both layers was achieved by modern optimization techniques on single gas permeation data. These parameters were validated by isobaric or transient diffusion measurements.
A Kinetic Study on Corn Gluten Hydrolysis
Authors: Apar D. K. , Özbek B. 
Published: February 2009

AbstractIn the present study, the hydrolysis of corn gluten was performed by using two commercial enzymes, Protamex and PTN, to investigate the reaction kinetics. The reactions were carried out for 10 min in 0.1 L of aqueous solutions containing 10, 20, 30 and 40 g protein L–1 corn gluten at various temperature and pH values. The progress of the reactions was monitored by a pH‐stat method. It was found that the kinetics of corn gluten hydrolysis by Protamex and PTN obey the Michaelis‐Menten model and higher catalytic yields were obtained with Protamex than PTN at all of the experimental conditions applied.
Minimum Circulation Velocity in a Spouted Bed Apparatus with Draft Tube
Authors: Kmiec A. , Ludwig W. , Szafran R. 
Published: February 2009

AbstractMeasurements of spouting characteristics were carried out in an apparatus consisting of two conical sections connected to a cylindrical section. Inside the lower conical section a draft tube was fixed. Results of minimum circulation velocity were obtained for an apparatus equipped with a draft tube of different inside diameters and lengths for different kinds of particles as well as for different static bed heights. Experimental data have been further analyzed to develop new correlations.
In Situ CO2 Capture in a Dual Fluidized Bed Biomass Steam Gasifier – Bed Material and Fuel Variation
Authors: Soukup G. , Pfeifer C. , Kreuzeder A. , Hofbauer H. 
Published: February 2009

AbstractThe AER (absorption enhanced reforming) process, based on the dual fluidized bed steam gasification process, uses a bed material which, apart from its function as heat carrier, acts as a CO2 transporting agent and selectively transfers CO2 from the gasification reactor to the combustion reactor. Thus, a hydrogen‐rich gas is produced (H2 55...70 vol.‐%db, CH4 8...13 vol.‐%db, CO 5...11 vol.‐%db as well as CO2 7...20 vol.‐%db). Seven different CaO containing bed materials were tested for their principal applicability to the AER process with special focus on their influence on tar production. The amount of tars was generally found to be five times lower than with conventional gasification (at 850 °C) despite the low gasification temperatures (600–700 °C). Due to these low gasification temperatures, biomass with high alkali contents (e.g., straw), indicating a low ash melting point (< 800 °C), can be used under AER conditions. In summary, the AER process is very effective owing to the integration of the heat of the chemical reaction of CO2 with CaO and the water‐gas shift reaction, which are both exothermic, into the gasification and the internal reforming of primary and secondary tars, which cuts off the formation of higher tars.
Limestone Attrition under Simulated Oxyfiring Fluidized‐Bed Combustion Conditions
Authors: Scala F. , Salatino P. 
Published: February 2009

AbstractLimestone attrition by surface wear was studied during the flue gas desulfurization under simulated fluidized‐bed (FB) oxyfiring conditions and hindered calcination. Bench‐scale experimental tests were carried out using well‐established techniques previously developed for the characterization of sulfation and attrition of sorbents in air‐blown atmospheric FB combustors. The experimental limestone conversion and attrition results were compared with those previously obtained with the same limestone under simulated air‐blown combustion conditions. The differences in the conversion and attrition extents and patterns associated with oxyfiring as compared to air‐blown atmospheric combustion were highlighted and related to the different particle morphologies and thicknesses of the sulfate layer. It was noted that attrition could play an important role in practical circulating FB combustor operation, by effectively enhancing particle sulfation under both oxyfiring and air‐blown combustion conditions.
Calix[4]arenes as Molecular Platforms for Magnetic Resonance Imaging (MRI) Contrast Agents
Authors: Schühle Daniel T. , Schatz Jürgen , Laurent Sophie , Vander Elst Luce , Muller Robert N. , Stuart Marc C. A. , Peters Joop A. 
Published: February 2009

AbstractThe novel amphipilic conjugate of a calix[4]arene with four Gd–1,4,7,10‐ tetra(carboxymethyl)‐1,4,7,10‐tetraazacyclododecane (DOTA) chelates has potential as a magnetic resonance imaging contrast agent, both in its monomeric and in its micellar form. The system, illustrated here with its nuclear magnetic relaxation profile, shows good relaxivities, thanks to its high rigidity.magnified imageAn amphiphilic conjugate 1 of a calix[4]arene with four Gd–DOTA chelates (DOTA=1,4,7,10‐tetra(carboxymethyl)‐1,4,7,10‐tetraazacyclododecane) was prepared and the properties relevant to its application as a magnetic resonance imaging (MRI) contrast agent were investigated by NMR, dynamic light scattering (DLS), and cryo‐electron microscopy (cryo‐TEM). The compound aggregates in water; its critical micelle concentration (cmc) is 0.21 mM (or 0.84 mM for Gd) at 37 °C. The relaxivity of the aggregates at 37 °C and 20 MHz (18.3 s−1 per mM Gd or 73.2 s−1 per mM 1) is about twice that of the monomer. Nuclear magnetic relaxation dispersion (NMRD) profiles show the relaxivity of the monomer to be almost independent of the magnetic field strength up to 60 MHz. At higher concentrations, the NMRD profiles exhibit a maximum at about 20 MHz, which is typical for high molecular volumes. The average water residence lifetime is 1.20 μs at 298 K as determined by 17O NMR. The rotational correlation time of the monomer (390 ns at 37 °C) is very close to the optimal value predicted for high‐field contrast agents. Monomer as well as micelles are very rigid systems with negligible local contributions to the overall rotational dynamics. The binding to human serum albumin (HSA) is significant (KA=1.2×103 M−1) and the relaxivity of the HSA adduct at 20 MHz is 24.6 s−1 per mM Gd or 98.5 s−1 per mM 1.
Radial‐Position‐Controlled Doping of CdS/ZnS Core/Shell Nanocrystals: Surface Effects and Position‐Dependent Properties
Authors: Yang Yongan , Chen Ou , Angerhofer Alexander , Cao Y. Charles 
Published: February 2009

AbstractEnergy transfer in doped semiconductor nanocrystals: Mn‐doped CdS/ZnS nanocrystals show interesting photoluminescence and EPR properties that are strongly dependent on the radial position of Mn dopants inside nanocrystals (see graphic). Furthermore, the results suggest a two‐step mechanism for the energy transfer inside the doped nanocrystals.magnified imageThis paper reports a study of the surface effects and position‐dependent properties of Mn‐doped CdS/ZnS core/shell nanocrystals, which were prepared by using a three‐step synthesis method. The Mn‐doping level of these nanocrystals was determined by a combination of electron paramagnetic resonance spectroscopy and inductively coupled plasma atomic emission spectroscopy. These nanocrystals were further characterized by using transmission electron microscopy and fluorescence spectroscopy. First, we found that injecting a large excess of zinc stearate at the end of nanocrystal synthesis can sufficiently eliminate the surface‐trap states from the doped CdS/ZnS core/shell nanocrystals and enhance their photoluminescence (PL) quantum yield (QY). Second, our results demonstrate that the Mn‐PL QY is determined by the product of the efficiency of energy transfer from an exciton inside the CdS core to a Mn ion (ΦET) and the efficiency of the emission from the Mn ion (ΦMn). Third, ΦMn strongly depends on the radial position of Mn ions in the doped core/shell nanocrystals. The position‐dependent changes of ΦMn nearly perfectly correlate to those of the linewidth of Mn EPR peaks: the higher the ΦMn, the narrower the linewidth of the Mn EPR peak. Fourth, the results demonstrate that ΦET depends on the Mn‐doping level as well as the inverse sixth power of the distance between a Mn ion and the center of its host nanocrystal. Accordingly, we propose a two‐step mechanism for the energy transfer: 1) the energy transfer from an exciton inside the CdS core to a bound exciton around a Mn center, which is the rate‐determining step and follows the Förster mechanism, and 2) the energy transfer from the bound exciton to the Mn center, which might follow a mechanism such as dark exciton (triplet exciton) or Auger transfer.