bluuebunny/crossref_metadata_2025_split huggingface dataset:
Improvement of soil carbon sink by cover crops in olive orchards under semiarid conditions. Influence of the type of soil and weed
Authors: Márquez-García F. , González-Sánchez E. J. , Castro-García S. , Ordóñez-Fernández R. 
Published: June 2013

The olive tree is one of the most important crops in Spain, and the main one in the region of Andalusia. Most orchards are rain-fed, with high slopes where conventional tillage (CT) is the primary soil management system used. These conditions lead to high erosion and a significant transport of organic carbon (OC). Moreover, soil tillage accelerates the oxidation of the OC. Cover crops (CC) are the conservation agriculture (CA) approach for woody crops. They are grown in-between tree rows to protect the soil against water erosion and their organic residues also help to increase the soil carbon (C) sink. Soil and OC losses associated to the sediment were measured over four seasons (2003-07) using micro-plots for the collection of runoff and sediment in five experimental fields located in rain-fed olive orchards in Andalusia. Two soil management systems were followed, CC and CT. Furthermore, the changes in soil C in both systems were analyzed at a depth of 0-25 cm. CC reduced erosion by 80.5%, and also OC transport by 67.7%. In addition, Cover crops increased soil C sink by 12.3 Mg ha-1 year-1 of carbon dioxide (CO2) equivalent, with respect to CT. CC in rainfed olive orchards in a Mediterranean climate could be an environmental friendly and profitable system for reducing erosion and increasing the soil C sink. However, C fixing rate is not regular, being very high for the initial years after shifting from CT to CC and gradually decreasing over time.
Transient Proteolytic Modification of Mesenchymal Stromal Cells Increases Lung Clearance Rate and Targeting to Injured Tissue
Authors: Kerkelä Erja , Hakkarainen Tanja , Mäkelä Tuomas , Raki Mari , Kambur Oleg , Kilpinen Lotta , Nikkilä Janne , Lehtonen Siri , Ritamo Ilja , Pernu Roni , Pietilä Mika , Takalo Reijo , Juvonen Tatu , Bergström Kim , Kalso Eija , Valmu Leena , Laitinen Saara , Lehenkari Petri , Nystedt Johanna 
Published: June 2013

AbstractSystemic infusion of therapeutic cells would be the most practical and least invasive method of administration in many cellular therapies. One of the main obstacles especially in intravenous delivery of cells is a massive cell retention in the lungs, which impairs homing to the target tissue and may decrease the therapeutic outcome. In this study we showed that an alternative cell detachment of mesenchymal stromal/stem cells (MSCs) with pronase instead of trypsin significantly accelerated the lung clearance of the cells and, importantly, increased their targeting to an area of injury. Cell detachment with pronase transiently altered the MSC surface protein profile without compromising cell viability, multipotent cell characteristics, or immunomodulative and angiogenic potential. The transient modification of the cell surface protein profile was sufficient to produce effective changes in cell rolling behavior in vitro and, importantly, in the in vivo biodistribution of the cells in mouse, rat, and porcine models. In conclusion, pronase detachment could be used as a method to improve the MSC lung clearance and targeting in vivo. This may have a major impact on the bioavailability of MSCs in future therapeutic regimes.
Rhodium(I)‐Catalyzed Arylation of β‐Chloro Ketones and Related Derivatives through Domino Dehydrochlorination/ Conjugate Addition
Authors: Jiang Quanbin , Guo Tenglong , Wang Qingfu , Wu Ping , Yu Zhengkun 
Published: June 2013

AbstractHighly efficient arylations of β‐chloro ketones and their ester and amide derivatives were achieved by means of domino dehydrochlorination/Rh(I)‐catalyzed conjugate addition. In situ generated vinyl ketones and their analogues were identified as the reaction intermediates. The present synthetic protocol provides a concise route to (chiral) β‐aryl ketones, esters, and amides.
Recent Developments in the Coordination Chemistry of Multidentate Ligands Featuring a Boron Moiety
Authors: Kameo Hajime , Nakazawa Hiroshi 
Published: June 2013

AbstractSynergistic effects between a transition metal and an appropriate ligand are required to promote a desired catalytic reaction. Ancillary ligands, provided by the versatile functionality of certain elements, give rise to an almost infinite potential for catalytic applications. Recently, the study of the synergistic effect between transition metals and boron has become easy on account of the development of various rigid multidentate frameworks. In this Review, we mainly focus on the chemistry of σ‐acceptor (Z‐type) borane ligands, particularly the key achievements of their unique reactivity and catalytic applications. Conceptually, the unique character of σ‐acceptor borane ligands provides a new strategy for developing remarkable reactivity and novel catalytic applications. This study discusses recent developments in the field in this context. The chemistry of boron‐based multidentate ligands that involve a covalent MB bond such as the boryl ligand (BR2), in which a boron moiety serves as a strong electron‐donating ligand, is also rapidly developing. The effect of the boryl ligand on a metal center is totally different from that of the borane (BR3) ligand, and different boron‐based functionalities confer opposing electronic properties to the metal center. The interesting character of boryl‐based chelating ligands augments their unique coordination chemistry, which is also summarized in this context.
Production of non‐proteinogenic amino acids from α‐keto acid precursors with recombinant Corynebacterium glutamicum
Authors: Kim Ju‐Yeon , Lee Young‐A , Wittmann Christoph , Park Jin‐Byung 
Published: June 2013

ABSTRACTIn the present work, Corynebacterium glutamicum was metabolically engineered for the enantioselective synthesis of non‐proteinogenic amino acids as valuable building blocks for pharmaceuticals and agrochemicals. The novel bio‐catalytic activity of C. glutamicum was obtained by heterologous expression of the branched chain aminotransferase IlvE from Escherichia coli. Upon this modification, the recombinant cells converted the α‐keto acid precursor 2‐(3‐hydroxy‐1‐adamantyl)‐2‐oxoethanoic acid (HOAE) into the corresponding amino acid 2‐(3‐hydroxy‐1‐adamantyl)‐(2S)‐amino ethanoic acid (HAAE). Similarly, also L‐tert‐leucine could be obtained from trimethyl pyruvate indicating a broader applicability of the novel strategy. In both cases, the amino group donor glutamate was supplied from the endogenous metabolism of the recombinant producer. Hereby, the uptake of the precursor and secretion of the product was supported by an enhanced cell permeability through treatment of ethambutol, which inhibits arabinosyl transferases involved in cell wall biosynthesis. The excretion of HAAE into the reaction medium was linked to the secretion of glutamate, indicating a similar mechanism for the export of both compounds. On the other hand, the efflux of L‐tert‐leucine appeared to be driven by active transport. Subsequent bioprocess engineering enabled HAAE and L‐tert‐leucine to be produced at a rate of 0.21 and 0.42 mmol (g dry cells)−1 h−1, respectively up to a final product titer of 40 mM. Beyond the given examples, integrated metabolic and cell envelop engineering might extend the production of a variety of other non‐proteinogenic amino acids as well as chiral amines by C. glutamicum. Biotechnol. Bioeng. 2013;110: 2846–2855. © 2013 Wiley Periodicals, Inc.
CRISPR‐Cas
Authors: Marchfelder Anita , Maier Lisa‐Katharina , Heidrich Nadja , Pul Ümit 
Published: June 2013

AbstractEiner der ältesten Konflikte auf Erden ist vermutlich der Existenzkampf zwischen Prokaryoten und Viren. Prokaryoten haben verschiedene Abwehrstrategien entwickelt, um sich gegen die allgegenwärtigen und zahlenmäßig überlegenen Viren zu schützen. Letztere besitzen wiederum Gegenmechanismen, mit denen sie den prokaryotischen Schutz umgehen. Ein beeindruckendes Beispiel für dieses ständige Wechselspiel der gegenseitigen Aufrüstung stellt das CRISPR‐Cas‐System dar. Ursprünglich in Prokaryoten entdeckt, verleiht das CRISPR‐Cas‐System eine adaptive und vererbbare Immunität gegenüber Viren und Plasmiden.
Wie Mollusken die Bergwelt erobern
Authors: Sturm Robert 
Published: June 2013

AbstractZoologische Kartierungen der vergangenen Jahrzehnte führten zutage, dass die Gewässer des zentralalpinen Raumes einer sukzessiven Besiedlung durch aquatische Weichtiere unterliegen. Während üppig bewachsene Gebirgsseen der montanen Höhenstufe über eine artenreiche Molluskenfauna verfügen können, dünnen sich die Arten‐ und Individuenzahl mit zunehmender Höhe immer mehr aus. Die Eroberung hochgelegener Gewässer bleibt wenigen, gegenüber verschiedenen Umweltfaktoren toleranten Arten vorbehalten. Diese Pionierspezies stammen aus den Familien der Schlammschnecken und der Kugelmuscheln. Die Verbreitung der Tiere selbst beruht auf passiven Transportmechanismen über andere Lebewesen, die als Träger fungieren. Zu diesen zählen nach gegenwärtigem Kenntnisstand Fische, Wiederkäuer und Wasservögel.
Curcumin und Multiple Sklerose
Authors: d'Astolfo Lisa , Hein Tabea , Schaffert Tonio , Scheithauer Florian , Wiederkehr Thomas 
Published: June 2013

AbstractMultiple Sklerose (MS) ist eine körpereigene Immunreaktion, die Zellen des zentralen Nervensystems angreift und in zunehmenden Maße schädigt. Die Schäden entstehen wahrscheinlich durch reaktive Sauerstoffspezies und Stickstoffmonoxid. Das Letzere wird von Stickstoffmonoxid‐Synthasen (NO) produziert. Im Tiermodell für MS, der experimentellen autoimmunen Encephalomyelitis (EAE), wurde eine erhöhte Expression von Arginase I festgestellt. Hemmung der Arginase verzögert das Auftreten der EAE‐Symptome. Da Arginasen und NO um dasselbe Substrat Arginin konkurrieren, könnte die Verdrängung von NO durch Arginase zu einer verringerten Stickstoffmonoxid‐Konzentration führen und dann über negative Rückkopplung zu einer verstärkten Produktion von NO. Es ist bekannt, dass die Prävalenz von MS in Gesellschaften, in denen täglich Curcumin verzehrt wird, niedriger ist als in der nördlichen Hemisphäre. Curcuma‐Bestandteile hemmen Arginasen in vitro und wechselwirken direkt mit dem Enzym. Daraus könnte ein Ansatz in der MS‐Behandlung abgeleitet werden.
Universitäre Biologielehrerausbildung auf dem Prüfstand
Authors: Großschedl Jörg , Harms Ute , Glowinski Ingrid 
Published: June 2013

AbstractWas sollte ein angehender Biologielehrer wissen und können? Schülerinnen und Schüler, die gebeten wurden, zukünftigen Referendaren Tipps für eine erfolgreiche Berufslaufbahn zu geben, nannten als Antwort neben Persönlichkeitsmerkmalen wie “Motivation” und “Spaß, mit jungen Menschen zu arbeiten” insbesondere “Fachkompetenz” und “die Fähigkeit, Unterricht anschaulich zu gestalten”. Fachwissenschaftliche, fachdidaktische sowie pädagogisch‐psychologische Lehrveranstaltungen im Universitätsstudium sollten zukünftige Lehrkräfte entsprechend vorbereiten – aber gelingt dies wirklich?
3D‐Zellkultur und komplexe Zellsysteme
Authors: Hauk Andrea 
Published: June 2013

AbstractZellen können so gezüchtet werden, dass sie nicht nur neben, sondern auch übereinander wachsen und in Kontakt mit anderen Zelltypen und deren Stoffwechselprodukten stehen. Durch diese Simulation können Fragen beantwortet werden, die sich mit einer herkömmlichen Monolayer‐Kultur nicht klären lassen.
Glühwürmchen, Taubenschwänzchen und Ameisenjungfern: Von der Wärme beflügelt
Authors: Petrischak Hannes 
Published: June 2013

AbstractIm Sommer lohnt es sich bei Tag und Nacht, das Geschehen im Garten zu verfolgen: Während Leuchtkäfermännchen blinkend ihre weniger mobilen Partnerinnen suchen, entfalten Ameisenjungfern in warmen Sommernächten ihre zarten Flügel. Auch der Vogelnachwuchs wird nun flügge. Die Jungen der Blindschleiche erblicken im Spätsommer das Licht der Welt. Mit der Wärme besuchen uns Wanderfalter aus dem Süden.
A Conserved Tyrosine in Ferritin Is a Molecular Capacitor
Authors: Ebrahimi Kourosh Honarmand , Hagedoorn Peter‐Leon , Hagen Wilfred R. 
Published: June 2013

AbstractA highly conserved tyrosine residue of unknown function is present in the vicinity of the di‐iron catalytic center of the ubiquitous iron‐storage protein ferritin. The di‐iron center with a gateway FeII/FeIII‐binding site nearby provides the vital iron‐storage mechanism of the protein. It is believed that, in eukaryotic ferritin, this center catalyzes simultaneous oxidation of two FeII ions, whereas in microbial ferritin it catalyzes simultaneous oxidation of three FeII ions. To understand the role of the conserved tyrosine, we studied the intermediates and products that are formed during catalysis of FeII oxidation in the di‐iron catalytic centers of the hyperthermophilic archaeal Pyrococcus furiosus ferritin and of eukaryotic human H ferritin. Based on our spectroscopic studies and modeling, we propose a merger of the models for eukaryotic and bacterial ferritin into a common mechanism of FeII oxidation in which the conserved tyrosine acts as a single‐electron molecular capacitor to facilitate oxidation of FeII.
Structure‐Dependent Electronic Nature of Star‐Shaped Oligothiophenes, Probed by Ensemble and Single‐Molecule Spectroscopy
Authors: Chung Heejae , Narita Tomoyuki , Yang Jaesung , Kim Pyosang , Takase Masayoshi , Iyoda Masahiko , Kim Dongho 
Published: June 2013

AbstractWe have investigated the photophysical properties of star‐shaped oligothiophenes with three terthiophene arms (meta to each other, S3) or six terthiophene arms (ortho‐, meta‐, and para‐arranged, S6) connected to an ethynylbenzene core to elucidate the relationship between their molecular structure and electronic properties by using a combination of ensemble and single‐molecule spectroscopic techniques. We postulate two different conformations for molecules S3 and S6 on the basis of the X‐ray structure of hexakis(5‐hexyl‐2‐thienlyethynyl)benzene and suggest the coexistence of these conformers by using spectroscopic methods. From the steady‐state spectroscopic data of compound S6, we show that the exciton is delocalized over the core structure, but that the meta‐linkage in compound S3 prevents the electronic communication between the arms. However, in single‐molecule spectroscopic measurements, we observed that some molecules of compound S3 showed long fluorescence lifetimes (about 1.4 ns) in the fluorescence‐intensity trajectories, which indicated that π electrons were delocalized along the meta linker. Based on these observations, we suggest that the delocalized exciton is intensely sensitive towards the dihedral angle between the core and the adjacent thiophene ring, as well as to the substituted position of the terthiophene arms. Our results highlight that the fluorescence lifetimes of compounds S3 and S6 are strongly correlated with the spatial location of their excitons, which is mainly affected by their conformation, that is, whether the innermost thiophene rings are facing each other or not. More interestingly, we observed that the difference between the degrees of ring‐torsional flexibility of compounds S3 and S6 results in their sharply contrasting fluorescence properties, such as a change in fluorescence intensity as a function of temperature.
Heterobimetallic Cuprates Consisting of a Redox‐Switchable, Silicon‐Based Metalloligand: Synthesis, Structures, and Electronic Properties
Authors: Styra Steffen , González‐Gallardo Sandra , Armbruster Felix , Oña‐Burgos Pascual , Moos Eric , Vonderach Matthias , Weis Patrick , Hampe Oliver , Grün Anneken , Schmitt Yvonne , Gerhards Markus , Menges Fabian , Gaffga Maximilian , Niedner‐Schatteburg Gereon , Breher Frank 
Published: June 2013

AbstractA series of bimetallic silyl halido cuprates consisting of the new tripodal silicon‐based metalloligand [κ3N‐Si(3,5‐Me2pz)3Mo(CO)3]− is presented (pz=pyrazolyl). This metalloligand is straightforwardly accessible by reacting the ambidentate ligand tris(3,5‐dimethylpyrazolyl)silanide ({Si(3,5‐Me2pz)3}−) with [Mo(CO)3(η6‐toluene)]. The compound features a fac‐coordinated tripodal chelating ligand and an outward pointing, “free” pyramidal silyl donor, which is easily accessible for a secondary coordination to other metal centers. Several bimetallic silyl halido cuprates of the general formula [CuX{μ‐κ1Si:κ3N‐Si(3,5‐Me2pz)3Mo(CO)3}]− (X=Cl, Br, I) have been synthesized. The electronic and structural properties of these complexes were probed in detail by X‐ray diffraction analysis, electrospray mass spectrometry, infrared‐induced multiphoton dissociation studies, cyclic voltammetry, spectroelectrochemistry, gas‐phase photoelectron spectroscopy, as well as UV/Vis and fluorescence spectroscopy. The heterobimetallic complexes contain linear two‐coordinate copper(I) entities with the shortest silicon–copper distances reported so far. Oxidation of the anionic complexes in methylene chloride and acetonitrile solutions at =−0.60 and −0.44 V (vs. ferrocene/ferrocenium (Fc/Fc+)), respectively, shows substantial reversibility. Based on various results obtained from different characterization methods, as well as density functional theory calculations, these oxidation events were attributed to the Mo0/MoI redox couple.
Modeling Parameters for Bubbly Flows
Authors: Bothe Melanie , Schlüter Michael 
Published: June 2013

AbstractIn den 1980er und 90er Jahren wurden intensive und erfolgreiche Forschungsprogramme durchgeführt, um die integrale Beschreibung und Auslegung von Blasensäulenreaktoren zu verbessern. Zur Jahrtausendwende wurden dann insbesondere lokale Mess‐ und Modellierungsmethoden verfeinert. Die Ergebnisse dieser lokalen Modelle sind bisher jedoch oft nur unzureichend in die integralen Auslegungsgleichungen eingeflossen, da eine große Lücke zwischen den betrachteten Zeit‐ und Ortsskalen besteht. Geeignete Mittelungs‐ und Filterverfahren fehlen ebenso wie Übertragungsregeln, um von den meist akademischen Stoffsystemen und Bedingungen zu industriellen Anwendungen zu gelangen. Der Artikel gibt einen Einblick in den Status quo im Bereich der Modellierung von Blasenströmungen und zeigt Wege auf, die künftig zu einer umfassenderen Modellierung und besseren Übertragbarkeit führen könnten.
Menthol
Authors: Schäfer Bernd 
Published: June 2013

AbstractDer Biosyntheseweg des Menthols umfasst, ausgehend von Isopentenyl‐ und Dimethylallyldiphosphat, acht diskrete Schritte. Technisch erhält man Menthol ausgehend von Kresol nach dem Haarmann‐Reimer‐Prozess durch klassische Racematspaltung. Der Takasago‐Prozess ist einer der bedeutendsten enantioselektiven Prozesse, die technisch ausgeübt werden. Schlüsselschritt ist eine rhodiumkatalysierte Doppelbindungsverschiebung. Der BASF‐Prozess zur Herstellung von Menthol geht von Citral aus und beinhaltet eine enantioselektive Hydrierung.
Sinensetin
Authors: Steinke Katrin , Jose Elena , Sicker Dieter , Siehl Hans‐Ullrich , Zeller Klaus‐Peter , Berger Stefan 
Published: June 2013

AbstractSinensetin wurde aus kaltgepresstem Orangenschalenöl isoliert und aus Ethanol umkristallisiert. Alle analytischen Spektren sind vollständig entweder im Hauptteil oder im online unter www.chiuz.de zusätzlichen Material zu diesem Artikel wiedergegeben. Die NMR‐ sowie die Massenspektren werden eingehend interpretiert und mit theoretischen Berechnungen der 13C chemischen Verschiebungen verglichen. Das Projekt ist eine Fortsetzung des Buches “Classics in Spectroscopy” von S. Berger und D. Sicker (Wiley‐VCH 2009).
Production of heavy minerals concentrate and bitumen from oil sands froth treatment tailings
Authors: Moran K. , Doiron J. , Hill A. , Sishtla C. 
Published: June 2013

AbstractIn producing valuable heavy minerals, including zircon and those bearing titanium dioxide, into a heavy minerals concentrate (HMC), the key technical challenges involve bitumen removal from mineral particle surfaces, rejection of fine gangue and recovery of residual solvent. (Organics and fines contamination severely sours downstream heavy minerals production performance). This is accomplished in a manner that is both conducive and integral with oil sands current bitumen production and processing operations. The Company's research and development efforts are based on sophisticated variations of common unit operations, including flotation, solvent extraction and vapour‐phase stripping. Experimentation has indicated optimal design parameters for these unit operations. A large‐scale physical demonstration was completed with performance that has met or exceeded expectations and, after several months of operation, commercial benefits arising from these novel processes have largely been confirmed and validated. Clean HMC with attractive mineralogy is produced containing residual bitumen values sufficiently low to affect high downstream recoveries of zircon (and titania), while producing coker‐feed quality bitumen.
Numerical analysis of non‐Newtonian blood flow and wall shear stress in realistic single, double and triple aorto‐coronary bypasses
Authors: Vimmr J. , Jonášová A. , Bublík O. 
Published: June 2013

SUMMARYConsidering the fact that hemodynamics plays an important role in the patency and overall performance of implanted bypass grafts, this work presents a numerical investigation of pulsatile non‐Newtonian blood flow in three different patient‐specific aorto‐coronary bypasses. The three bypass models are distinguished from each other by the number of distal side‐to‐side and end‐to‐side anastomoses and denoted as single, double and triple bypasses. The mathematical model in the form of time‐dependent nonlinear system of incompressible Navier–Stokes equations is coupled with the Carreau–Yasuda model describing the shear‐thinning property of human blood and numerically solved using the principle of the SIMPLE algorithm and cell‐centred finite volume method formulated for hybrid unstructured tetrahedral grids. The numerical results computed for non‐Newtonian and Newtonian blood flow in the three aorto‐coronary bypasses are compared and analysed with emphasis placed on the distribution of cycle‐averaged wall shear stress and oscillatory shear index. As shown in this study, the non‐Newtonian blood flow in all of the considered bypass models does not significantly differ from the Newtonian one. Our observations further suggest that, especially in the case of sequential grafts, the resulting flow field and shear stimulation are strongly influenced by the diameter of the vessels involved in the bypassing. Copyright © 2013 John Wiley & Sons, Ltd.
Genotypic and phenotypic variation in transmission traits of a complex life cycle parasite
Authors: Louhi Katja‐Riikka , Karvonen Anssi , Rellstab Christian , Jokela Jukka 
Published: June 2013

AbstractCharacterizing genetic variation in parasite transmission traits and its contribution to parasite vigor is essential for understanding the evolution of parasite life‐history traits. We measured genetic variation in output, activity, survival, and infection success of clonal transmission stages (cercaria larvae) of a complex life cycle parasite (Diplostomum pseudospathaceum). We further tested if variation in host nutritional stage had an effect on these traits by keeping hosts on limited or ad libitum diet. The traits we measured were highly variable among parasite genotypes indicating significant genetic variation in these life‐history traits. Traits were also phenotypically variable, for example, there was significant variation in the measured traits over time within each genotype. However, host nutritional stage had no effect on the parasite traits suggesting that a short‐term reduction in host resources was not limiting the cercarial output or performance. Overall, these results suggest significant interclonal and phenotypic variation in parasite transmission traits that are not affected by host nutritional status.