bluuebunny/crossref_metadata_2025_split huggingface dataset:
Neues Leben im Weltnaturerbe Wattenmeer. Globalisierung unter Wasser
Authors: Buschbaum Christian , Reise Karsten 
Published: June 2010

AbstractNeue Untersuchungen im Wattenmeer decken eine Überflutung durch eingeschleppte Arten auf, die sich in den vergangenen Jahren vor allem im Flachwasserbereich direkt unterhalb der Gezeitenzone ausbreiten konnten. Hier sind sie Nutznießer der durch den globalen Klimawandel verursachten ansteigenden Wassertemperaturen. Entstanden ist eine diverse Lebensgemeinschaft von Algen und Wirbellosen, die sich fortlaufend weiter verändert. Neben der strukturellen Komplexität der biogenen Habitate hat besonders die funktionelle Gruppe der filtrierenden Organismen zugenommen. Insgesamt ist das gesamte Ökosystem in einen Umbruch geraten, der nicht mehr umkehrbar ist.
Evolutionärer Stammbaum der Blütenpflanzen – neue Zugehörigkeiten, neue Namen
Authors: Cole Theodor C. H. 
Published: June 2010

AbstractSeit Jahrhunderten bemühen sich Botaniker, “Ordnung ins System” zu bringen – für die Blütenpflanzen ist man diesem Ziel nun sehr nah. Ein Konsortium international führender Pflanzensystematiker hat die Ergebnisse der molekularen Phylogenie der vergangenen drei Jahrzehnte zusammengefasst und unter Berücksichtigung morphologisch‐anatomischer und chemotaxonomischer Gesichtpunkte daraus die Verwandtschaftsbeziehungen der Blütenpflanzen reinterpretiert. Es resultiert ein evolutionär begründeter Stammbaum, der auf der Ebene der Hauptgruppen (Ordnungen und Familien) nun ein hohes Maß an Stabilität aufweist.
Nachrichten des Verbandes Biologie, Biowissenschaften & Biomedizin in Deutschland
Authors: Tautz Diethard 
Published: June 2010

AbstractAus den Fachgesellschaften:Deutsche Ornithologen‐GesellschaftBundesdelegiertenversammlungAusbildung und KarriereLandesverbände:Nordrhein‐WestfalenBaden‐WürttembergSaarlandRheinland‐Pfalz
Syngas fermentation to biofuel: Evaluation of carbon monoxide mass transfer coefficient (kLa) in different reactor configurations
Authors: Munasinghe Pradeep Chaminda , Khanal Samir Kumar 
Published: June 2010

AbstractLignocellulosic biomass such as agri‐residues, agri‐processing by‐products, and energy crops do not compete with food and feed, and is considered to be the ideal renewable feedstocks for biofuel production. Gasification of biomass produces synthesis gas (syngas), a mixture primarily consisting of CO and H2. The produced syngas can be converted to ethanol by anaerobic microbial catalysts especially acetogenic bacteria such as various clostridia species.One of the major drawbacks associated with syngas fermentation is the mass transfer limitation of these sparingly soluble gases in the aqueous phase. One way of addressing this issue is the improvement in reactor design to achieve a higher volumetric mass transfer coefficient (kLa). In this study, different reactor configurations such as a column diffuser, a 20‐μm bulb diffuser, gas sparger, gas sparger with mechanical mixing, air‐lift reactor combined with a 20‐μm bulb diffuser, air‐lift reactor combined with a single gas entry point, and a submerged composite hollow fiber membrane (CHFM) module were employed to examine the kLa values. The kLa values reported in this study ranged from 0.4 to 91.08 h−1. The highest kLa of 91.08 h−1 was obtained in the air‐lift reactor combined with a 20‐μm bulb diffuser, whereas the reactor with the CHFM showed the lowest kLa of 0.4 h−1. By considering both the kLa value and the statistical significance of each configuration, the air‐lift reactor combined with a 20‐μm bulb diffuser was found to be the ideal reactor configuration for carbon monoxide mass transfer in an aqueous phase. © 2010 American Institute of Chemical Engineers Biotechnol. Prog., 2011
Streptococcus mutans Inhibits Candida albicans Hyphal Formation by the Fatty Acid Signaling Molecule trans‐2‐Decenoic Acid (SDSF)
Authors: Vílchez Ramiro , Lemme André , Ballhausen Britta , Thiel Verena , Schulz Stefan , Jansen Rolf , Sztajer Helena , Wagner‐Döbler Irene 
Published: June 2010

AbstractIn the human mouth, fungi and several hundred species of bacteria coexist. Here we report a case of interkingdom signaling in the oral cavity: A compound excreted by the caries bacterium Streptococcus mutans inhibits the morphological transition from yeast to hyphae, an important virulence trait, in the opportunistic fungus Candida albicans. The compound excreted by S. mutans was originally studied because it inhibited signaling by the universal bacterial signal autoinducer‐2 (AI‐2), determined by the luminescence of a Vibrio harveyi sensor strain. The inhibitor was purified from cell‐free culture supernatants of S. mutans guided by its activity. Its chemical structure was elucidated by using NMR spectroscopy and GC‐MS and proved to be trans‐2‐decenoic acid. We show that trans‐2‐decenoic acid does not inhibit AI‐2‐specific signaling, but rather the luciferase reaction used for its detection. A potential biological role of trans‐2‐decenoic acid was then discovered. It is able to suppress the transition from yeast to hyphal morphology in the opportunistic human pathogen Candida albicans at concentrations that do not affect growth. The expression of HWP1, a hyphal‐specific signature gene of C. albicans, is abolished by trans‐2‐decenoic acid. trans‐2‐Decenoic acid is structurally similar to the diffusible signal factor (DSF) family of interkingdom‐signaling molecules and is the first member of this family from a Gram‐positive organism (Streptococcus DSF, SDSF). SDSF activity was also found in S. mitis, S. oralis, and S. sanguinis, but not in other oral bacteria. SDSF could be relevant in shaping multispecies Candida bacteria biofilms in the human body.
An RNA Aptamer That Selectively Inhibits the Enzymatic Activity of Protein Tyrosine Phosphatase 1B in vitro
Authors: Townshend Brent , Aubry Isabelle , Marcellus Richard C. , Gehring Kalle , Tremblay Michel L. 
Published: June 2010

AbstractSELEX was used to create an RNA aptamer targeted to protein tyrosine phosphatase 1B (PTP1B), an enzyme implicated in type 2 diabetes, breast cancer and obesity. We found an aptamer that strongly inhibits PTP1B in vitro with a Ki of less than 600 pM. This slow‐binding, high‐affinity inhibitor is also highly selective, with no detectable effect on most other tested phosphatases and approximately 300:1 selectivity over the closely related TC‐PTP. Through controlled synthesis of truncated variants of the aptamer, we isolated shorter forms that inhibit PTP1B. We also investigated various single‐nucleotide modifications to probe their effects on the aptamer's secondary structure and inhibition properties. This family of aptamers represents an exciting option for the development of lead nucleotide‐based compounds in combating several human cancers and metabolic diseases.
The Torsional Barriers of 2‐Hydroxy‐ and 2‐Fluorobiphenyl: Small but Measurable
Authors: Mazzanti Andrea , Lunazzi Lodovico , Ruzziconi Renzo , Spizzichino Sara , Schlosser Manfred 
Published: June 2010

AbstractBy making use of a novel diastereotopicity probe, namely C(CF3)2OH, it has been possible to measure by very low temperature 19F NMR spectroscopy the elusive aryl–aryl rotation barriers of biphenyls bearing an OH or F group in one ortho position. The experimental values (5.4 and 4.4 kcal mol−1, respectively) are matched by those from ab initio calculations (5.3 and 4.3 kcal mol−1, respectively).
The Wacker Process: Inner‐ or Outer‐Sphere Nucleophilic Addition? New Insights from Ab Initio Molecular Dynamics
Authors: Comas‐Vives Aleix , Stirling András , Lledós Agustí , Ujaque Gregori 
Published: June 2010

AbstractThe Wacker process consists of the oxidation of ethylene catalyzed by a PdII complex. The reaction mechanism has been largely debated in the literature; two modes for the nucleophilic addition of water to a Pd‐coordinated alkene have been proposed: syn‐inner‐ and anti‐outer‐sphere mechanisms. These reaction steps have been theoretically evaluated by means of ab initio molecular dynamics combined with metadynamics by placing the [Pd(C2H4)Cl2(H2O)] complex in a box of water molecules, thereby resembling experimental conditions at low [Cl−]. The nucleophilic addition has also been evaluated for the [Pd(C2H4)Cl3]− complex, thus revealing that the water by chloride ligand substitution trans to ethene is kinetically favored over the generally assumed cis species in water. Hence, the resulting trans species can only directly undertake the outer‐sphere nucleophilic addition, whereas the inner‐sphere mechanism is hindered since the attacking water is located trans to ethene. In addition, all the simulations from the [Pd(C2H4)Cl2(H2O)] species (either cis or trans) support an outer‐sphere mechanism with a free‐energy barrier compatible with that obtained experimentally, whereas that for the inner‐sphere mechanism is significantly higher. Moreover, additional processes for a global understanding of the Wacker process in solution have also been identified, such as ligand substitutions, proton transfers that involve the aquo ligand, and the importance of the trans effect of the ethylene in the nucleophilic addition attack.
Theoretical Design of High‐Spin Polycyclic Hydrocarbons
Authors: Trinquier Georges , Suaud Nicolas , Malrieu Jean‐Paul 
Published: June 2010

AbstractHigh‐spin organic structures can be obtained from fused polycyclic hydrocarbons, by converting selected peripheral HC(sp2) sites into H2C(sp3) ones, guided by Ovchinnikov’s rule. Theoretical investigation is performed on a few examples of such systems, involving three to twelve fused rings, and maintaining threefold symmetry. Unrestricted DFT (UDFT) calculations, including geometry optimizations, confirm the high‐spin multiplicity of the ground state. Spin‐density distributions and low‐energy spectra are further studied through geometry‐dependent Heisenberg–Hamiltonian diagonalizations and explicit correlated ab initio treatments, which all agree on the high‐spin character of the suggested structures, and locate the low‐lying states at significantly higher energies. In particular, the lowest‐lying state of lower multiplicity is always found to be higher than kT at room temperature (at least ten times higher). Simplification of the ferromagnetic organization based on sets of semilocalized nonbonding orbitals is proposed. Molecular architectures are thus conceived in which the ferromagnetically‐coupled unpaired electrons tally up to one third of the involved conjugated carbons. Connecting such building blocks should provide bidimensional materials endowed with robust magnetic properties.
Sonication‐Triggered Instantaneous Gel‐to‐Gel Transformation
Authors: Yu Xudong , Liu Qian , Wu Junchen , Zhang Mingming , Cao Xinhua , Zhang Song , Wang Qi , Chen Liming , Yi Tao 
Published: June 2010

AbstractTwo new peptide‐based isomers containing cholesterol and naphthalic groups have been designed and synthesized. We found that the position of L‐alanine in the linker could tune the gelation properties and morphologies. The molecule with the L‐alanine residue positioned in the middle of the linker (1 b) shows better gelation behavior than that with L‐alanine directly linked to the naphthalimido moiety (1 a). As a result, a highly thermostable organogel of 1 b with a unique core–shell structure was obtained at high temperature and pressure in acetonitrile. Moreover, the gels of 1 a and 1 b could undergo an instantaneous gel‐to‐gel transition triggered by sonication. Ultrasound could break the core–shell microsphere of 1 b and the micelle structure of 1 a into entangled fibers. By studying the mechanism of the sonication‐triggered gel‐to‐gel transition process of these compounds, it can be concluded that ultrasound has a variety of effects on the morphology, such as cutting, knitting, unfolding, homogenizing, and even cross‐linking. Typically, ultrasound can cleave and homogenize π‐stacking and hydrophobic interactions among the gel molecules and then reshape the morphologies to form a new gel. This mechanism of morphology transformation triggered by sonication might be attractive in the field of material storage and controlled release.
Cationic Reverse Micelles Create Water with Super Hydrogen‐Bond‐Donor Capacity for Enzymatic Catalysis: Hydrolysis of 2‐Naphthyl Acetate by α‐Chymotrypsin
Authors: Moyano Fernando , Falcone R. Dario , Mejuto J. C. , Silber Juana J. , Correa N. Mariano 
Published: June 2010

AbstractReverse micelles (RMs) are very good nanoreactors because they can create a unique microenvironment for carrying out a variety of chemical and biochemical reactions. The aim of the present work is to determine the influence of different RM interfaces on the hydrolysis of 2‐naphthyl acetate (2‐NA) by α‐chymotrypsin (α‐CT). The reaction was studied in water/benzyl‐n‐hexadecyldimethylammonium chloride (BHDC)/benzene RMs and, its efficiency compared with that observed in pure water and in sodium 1,4‐bis‐2‐ethylhexylsulfosuccinate (AOT) RMs. Thus, the hydrolysis rates of 2‐NA catalyzed by α‐CT were determined by spectroscopic measurements. In addition, the method used allows the joint evaluation of the substrate partition constant Kp between the organic and the micellar pseudophase and the kinetic parameters: catalytic rate constant kcat, and the Michaelis constant KM of the enzymatic reaction. The effect of the surfactant concentration on the kinetics parameters was determined at constant W0=[H2O]/[surfactant], and the variation of W0 with surfactant constant concentration was investigated. The results show that the classical Michaelis–Menten mechanism is valid for α‐CT in all of the RMs systems studied and that the reaction takes place at both RM interfaces. Moreover, the catalytic efficiency values kcat/KM obtained in the RMs systems are higher than that reported in water. Furthermore, there is a remarkable increase in α‐CT efficiency in the cationic RMs in comparison with the anionic system, presumably due to the unique water properties found in these confined media. The results show that in cationic RMs the hydrogen‐bond donor capacity of water is enhanced due to its interaction with the cationic interface. Hence, entrapped water can be converted into “super‐water” for the enzymatic reaction studied in this work.
Preparation of Organoaluminum Reagents from Propargylic Bromides and Aluminum Activated by PbCl2 and Their Regio‐ and Diastereoselective Addition to Carbonyl Derivatives
Authors: Guo Li‐Na , Gao Hongjun , Mayer Peter , Knochel Paul 
Published: June 2010

AbstractVarious propargylic and allenic aluminum reagents have been easily prepared by a direct insertion of aluminum into propargylic bromides in the presence of PbCl2 (1 mol %). These organoaluminum reagents react with carbonyl compounds to afford the corresponding allenic alcohols or homopropargylic alcohols in good to excellent yields with high regio‐ and diastereoselectivity.
Reactivity of the Latent 12‐Electron Fragment [Rh(PiBu3)2]+ with Aryl Bromides: ArylBr and Phosphine Ligand CH Activation
Authors: Townsend Nell S. , Chaplin Adrian B. , Naser M. Abu , Thompson Amber L. , Rees Nicholas H. , Macgregor Stuart A. , Weller Andrew S. 
Published: June 2010

AbstractOxidative addition of aryl bromides to 12‐electron [Rh(PiBu3)2][BArF4] (ArF=3,5‐(CF3)2C6H3) forms a variety of products. With p‐tolyl bromides, RhIII dimeric complexes result [Rh(PiBu3)2(o/p‐MeC6H4)(μ‐Br)]2[BArF4]2. Similarly, reaction with p‐ClC6H4Br gives [Rh(PiBu3)2(p‐ClC6H4)(μ‐Br)]2[BArF4]2. In contrast, the use of o‐BrC6H4Me leads to a product in which toluene has been eliminated and an isobutyl phosphine has undergone CH activation: [Rh{PiBu2(CH2CHCH3CH2)}(PiBu3)(μ‐Br)]2[BArF4]2. Trapping experiments with ortho‐bromo anisole or ortho‐bromo thioanisole indicate that a possible intermediate for this process is a low‐coordinate RhIII complex that then undergoes CH activation. The anisole and thioanisole complexes have been isolated and their structures show OMe or SMe interactions with the metal centre alongside supporting agostic interactions, [Rh(PiBu3)2(C6H4OMe)Br][BArF4] (the solid‐state structure of the 5‐methyl substituted analogue is reported) and [Rh(PiBu3)2(C6H4SMe)Br][BArF4]. The anisole‐derived complex proceeds to give [Rh{PiBu2(CH2CHCH3CH2)}(PiBu3)(μ‐Br)]2[BArF4]2, whereas the thioanisole complex is unreactive. The isolation of [Rh(PiBu3)2(C6H4OMe)Br][BArF4] and its onward reactivity to give the products of CH activation and aryl elimination suggest that it is implicated on the pathway of a σ‐bond metathesis reaction, a hypothesis strengthened by DFT calculations. Calculations also suggest that CH bond cleavage through phosphine‐assisted deprotonation of a non‐agostic bond is also competitive, although the subsequent protonation of the aryl ligand is too high in energy to account for product formation. CH activation through oxidative addition is also ruled out on the basis of these calculations. These new complexes have been characterised by solution NMR/ESIMS techniques and in the solid‐state by X‐ray crystallography.
Preparation of Imidazolin‐2‐iminato Molybdenum and Tungsten Benzylidyne Complexes: A New Pathway to Highly Active Alkyne Metathesis Catalysts
Authors: Haberlag Birte , Wu Xian , Brandhorst Kai , Grunenberg Jörg , Daniliuc Constantin G. , Jones Peter G. , Tamm Matthias 
Published: June 2010

AbstractThe reaction of [PhCMBr3(dme)] (dme=1,2‐dimethoxyethane) with the hexafluoro‐tert‐butoxides LiX or KX [X=OC(CF3)2Me] afforded the benzylidyne complexes [PhCMX3(dme)] (2 a: M=W, 2 b: M=Mo), which further reacted with the lithium reagent Li(ImtBuN), generated with MeLi from 1,3‐di‐tert‐butylimidazolin‐2‐imine (ImtBuNH), to form the imidazolin‐2‐iminato complexes [PhCMX2(ImtBuN)] (3 a: M=W, 3 b: M=Mo). The propylidyne complex [EtCMoX2(NImtBu)] (4) was obtained by treatment of 3 b with an excess of 3‐hexyne. Complexes 3 a and 3 b are able to efficiently catalyse alkyne cross metathesis of various 3‐pentynyl benzyl ethers 5 and benzoic esters 7 at room temperature, to afford 2‐butyne and the corresponding diethers 6 and diesters 8. The tungsten complex 3 a proved to be a superior catalyst for ring‐closing alkyne metathesis, and the [10]cyclophanes 10 and 12 were synthesised in high yield from 1,3‐bis(3‐pentynyloxymethyl)benzene (9) and bis(3‐pentynyl) phthalate (11), respectively. The molecular structures of compounds 2 a, 2 b, 3 a, 3 b, 4, and 12 were determined by single‐crystal X‐ray diffraction. DFT calculations have been carried out for catalyst systems based on the imidazolin‐2‐iminato tungsten and molybdenum complexes 3 a and 3 b by choosing the alkyne metathesis of 2‐butyne as the model reaction; the studies revealed a lower activation barrier for the tungsten system.
Ferrocene‐Substituted Dithio‐o‐Carborane Isomers: Influence on the Native Conformation of Myoglobin Protein
Authors: Wu Chunhui , Xu Baohua , Zhao Juan , Jiang Qibai , Wei Fadong , Jiang Hui , Wang Xuemei , Yan Hong 
Published: June 2010

AbstractBiointeractions between two organometallic compounds, a pair of ferrocene‐substituted dithio‐o‐carborane isomers (C14H20B10FeS2; denoted as FcSB1 and FcSB2), and myoglobin (Mb) have been investigated by means of electrochemistry, fluorescence, circular dichroism, and UV/Vis absorption spectroscopy. Our observations demonstrate that FcSB1 and FcSB2 could coordinate to the axial position trans to the histidine imidazole that induces the change of the heme iron from the high spin state to the low spin state and the changes of the conformation of the aromatic fluorophores of the selected heme protein. Such influences attribute to the structural features of FcSB1 and FcSB2 containing sulfur donor atoms and hydrophobic ferrocenyl and carboranyl units that leads to specific binding modalities with Mb. This study provides an insight into the understanding of relevant biointeractions between the new type of ferrocene–carborane conjugates and hemoproteins, and might shed light on the promising bioapplications of these multifunctional organometallic complexes.
ChemInform Abstract: Synthesis and Crystal Structure of Metal(I) Hydrogen Sulfates — Ag(H3O)(HSO4)2, Ag2(HSO4)2(H2SO4), AgHSO4, and Hg2(HSO4)2.
Authors: Stiewe A. , Kemnitz E. , Troyanov S. 
Published: June 2010

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Synthesis and Structure of (NH4)2[(AuI4)(MI4)] (M: Ga, In).
Authors: Schulz Lang E. , Abram U. , Straehle J. , Vazquez‐Lopez E. M. 
Published: June 2010

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Synthesis and Crystal Structure of Tl2PdCl4.
Authors: Schuepp Barbara , Keller Hans‐Lothar 
Published: June 2010

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: High Rate Electrodes of V2O5 Aerogel.
Authors: Passerini S. , Ressler J. J. , Le D. B. , Owens B. B. , Smyrl W. H. 
Published: June 2010

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Anisotropic Templating Effect in the Formation of Two‐Dimensional Anionic Cadmium—Thiocyanate Coordination Solids [(12‐crown‐4)2Cd][Cd2(SCN)6] (I) and [(12‐crown‐4)2Cd][Cd3(SCN)8] (II) with Checkerboard and Herringbone Patterns, Respectively.
Authors: Zhang Hong , Wang Ximin , Zhu H. , Xiao W. , Zhang Kecong , Teo Boon K. 
Published: June 2010

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Organothermal Synthesis and Characterization of Nanocrystalline β‐Indium Sulfide.
Authors: Yu Shu‐Hong , Shu Lei , Wu Yong‐Sheng , Yang Jian , Xie Yi , Qian Yi‐Tai 
Published: June 2010

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Gliclazide
Authors: Parvez Masood , Arayne M. Saeed , Zaman M. Kamran , Sultana Najma 
Published: June 2010

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Enantioselective Synthesis of β‐Amino Sulfones by Aza‐Michael Addition to Alkenyl Sulfones.
Authors: Enders Dieter , Mueller Stephan F. , Raabe Gerhard 
Published: June 2010

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.