bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nanosafety Research—Are We on the Right Track?
Authors: Krug Harald F. 
Published: October 2014

AbstractThe number of studies that have been published on the topic of nanosafety speaks for itself. We have seen an almost exponential rise over the past 15 years or so in the number of articles on nanotoxicology. Although only a couple of hundred papers had appeared on the topic of “Nanomaterials: environmental and health effects” before 2000, this number has exploded to over 10 000 since 2001. Most of these studies, however, do not offer any kind of clear statement on the safety of nanomaterials. On the contrary, most of them are either self‐contradictory or arrive at completely erroneous conclusions. Three years ago in this Journal we underscored the deficiencies in the way these studies were designed and pointed out the sources of error in the methods used. Now, on the basis of a comprehensive review of the literature and with the help of selected toxicological end points, we attempt to indicate where the significant weaknesses of these studies lie and what we must improve in the future.
Biosynthesis of the Halogenated Mycotoxin Aspirochlorine in Koji Mold Involves a Cryptic Amino Acid Conversion
Authors: Chankhamjon Pranatchareeya , Boettger‐Schmidt Daniela , Scherlach Kirstin , Urbansky Barbara , Lackner Gerald , Kalb Daniel , Dahse Hans‐Martin , Hoffmeister Dirk , Hertweck Christian 
Published: October 2014

AbstractAspirochlorine (1) is an epidithiodiketopiperazine (ETP) toxin produced from koji mold (Aspergillus oryzae), which has been used in the oriental cuisine for over two millennia. Considering its potential risk for food safety, we have elucidated the molecular basis of aspirochlorine biosynthesis. By a combination of genetic and chemical analyses we found the acl gene locus and identified the key role of AclH as a chlorinase. Stable isotope labeling, biotransformation, and mutational experiments, analysis of intermediates and an in vitro adenylation domain assay gave totally unexpected insights into the acl pathway: Instead of one Phe and one Gly, two Phe units are assembled by an iterative non‐ribosomal peptide synthetase (NRPS, AclP), followed by halogenation and an unprecedented Phe to Gly amino acid conversion. Biological assays showed that both amino acid transformations are required to confer cytotoxicity and antifungal activity to the mycotoxin.
Organocatalytic Asymmetric Arylative Dearomatization of 2,3‐Disubstituted Indoles Enabled by Tandem Reactions
Authors: Zhang Yu‐Chen , Zhao Jia‐Jia , Jiang Fei , Sun Si‐Bing , Shi Feng 
Published: October 2014

AbstractThe organocatalytic asymmetric arylative dearomatization of indoles was achieved through two tandem approaches involving 2,3‐disubstituted indoles and quinone imine ketals. One approach utilized the enantioselective cascade 1,4 addition/alcohol elimination reaction, the other employed the one‐pot tandem arylative dearomatization/transfer hydrogenation sequence. In both cases, enantiomerically pure indole derivatives that bear an all‐carbon quaternary stereogenic center were generated in high yields and excellent stereoselectivities (all d.r.>95:5, up to 99 % ee).
Investigation of Single‐Drug‐Encapsulating Liposomes using the Nano‐Impact Method
Authors: Cheng Wei , Compton Richard G. 
Published: October 2014

AbstractEncapsulating liposomes are widely used for controlled drug delivery. We report the use of nano‐impact experiments for the electrochemical attomolar quantification of the liposome load, uniquely at the single liposome level, using vitamin C encapsulated liposomes as a model. The size of the liposomes and their picomolar concentration are also determined in biological buffer in real time.
Distributed Model Predictive Control Method for Optimal Coordination of Signal Splits in Urban Traffic Networks
Authors: Ye Bao‐Lin , Wu Weimin , Mao Weijie 
Published: October 2014

AbstractCoordination and control approaches based on model predictive control (MPC) have been widely investigated for traffic signal control in urban traffic networks. However, due to the complex non‐linear characters of traffic flows and the large scale of traffic networks, a basic challenge faced by these approaches is the high online computational complexity. In this paper, to reduce the computational complexity and improve the applicability of traffic signal control approaches based on MPC in practice, we propose a distributed MPC approach (DCA‐MPC) to coordinate and optimize the signal splits. Instead of describing the dynamics of traffic flow within each link of the traffic network with a simplified linear model, we present an improved nonlinear traffic model. Based on the nonlinear model, an MPC optimization framework for the signal splits control is developed, whereby the interactions between subsystems are accurately modeled by employing two interconnecting constraints. In addition, by designing a novel dual decomposition strategy, a distributed coordination algorithm is proposed. Finally, with a benchmark traffic network, experimental results are given to illustrate the effectiveness of the proposed method.
Bauphysikalische Aspekte bei Ausführung von hochwertig genutzten Weißen Wannen
Authors: Rucker‐Gramm Petra 
Published: October 2014

AbstractDie hochwertige Nutzung von Kellergeschossen zum Beispiel als Wohn‐ oder Arbeitsraum setzt voraus, dass bauphysikalische Aspekte in der Planung, Ausführung und Nutzung Berücksichtigung finden. Vornehmliches Ziel ist die Sicherstellung eines behaglichen Raumklimas und der Vermeidung von Tauwasser‐ und Schimmelpilzbildung. Zu diesem Zweck ist der Feuchteeintrag durch die Gebäudehülle und durch die Nutzung zu begrenzen. Der Feuchtetransport durch die Gebäudehülle ist hierbei von untergeordneter Bedeutung, da dieser bei Einhaltung der Vorgaben der WU‐Richtlinie nicht stattfindet. Auch die Abgabe der Baufeuchte ist nur in den ersten Monaten nach Nutzungsbeginn relevant. Wesentlichen Einfluss auf den Feuchtegehalt im Raum hat die Nutzung. Durch angepasste Lüftung muss der nutzungsbedingte Feuchteeintrag abgeführt werden. Feuchtespeichernde Materialien an den Innenoberflächen können das Raumklima zusätzlich positiv beeinflussen, indem Feuchtespitzen abgefangen werden. Durch eine wärmeschutztechnische Optimierung der Gebäudehülle wird erreicht, dass die Innenoberflächentemperaturen erhöht werden. Dies resultiert in Bauteiltemperaturen, die von den Nutzern als behaglich empfunden werden. Zudem reduziert sich dadurch das Risiko der Schimmel‐ und Tauwasserbildung. Unter dem Aspekt der Energieverluste im Bereich von Wärmebrücken und der damit verbundenen Kosten ist die Ausführung einer außengedämmten WU‐Konstruktion der innengedämmten Variante vorzuziehen.Aspects of building physics in the course of constructing high grade white tanksThe premium use of basements for example as living or working space requires that aspects of the building physics in the planning, implementation and utilization are taken into account. The overriding objective is to ensure a comfortable indoor climate and the prevention of condensation and mould formation. In that regard, moisture entry shall be limited by the building envelope and by its use. The moisture transport through the building envelope is here of secondary importance, since this shall not occur when the requirements of the WU‐Directive are met. Building moisture is only relevant in the first months after the start of use. Significant influence on the moisture content in the room has its use. Adequate ventilation has to remove use‐related moisture entry. Moisture‐absorbing materials on the inner surface of walls can further positively influence the indoor climate as humidity peaks are reduced. A heat‐protective technical optimization of the building envelope leads into increasing surface temperatures of the structural components. This results in surface temperatures, which are perceived by users as being comfortable. In addition, the risk of mould and condensation is reduced. Under the aspect of energy losses in the area of thermal bridges and the associated costs, the execution of an externally insulated WU‐construction is preferable vs. the internally insulated alternative.
Abdichten von Rissen und Hohlräumen in wasserundurchlässigen Bauwerken aus Beton
Authors: Graeve Holger 
Published: October 2014

AbstractAußenbauteile aus Beton, die neben ihrer tragenden, aussteifenden oder raumabschließenden Funktion gleichzeitig die Abdichtung zu erbringen haben, erfordern bei aller Sorgfalt in Konstruktion und Ausführung zusätzliche nachträgliche Injektionsmaßnahmen. Abdichtende Injektionen sind notwendig, um die Funktion einer wasserundurchlässigen Betonkonstruktion vollständig sicherzustellen. Sie gewährleisten auch den Korrosionsschutz der Bewehrung eines Stahlbetonbauteils.Konstruktive, betontechnologische und ausführungstechnische Maßnahmen können Rissbildung nicht gänzlich verhindern. Während des Erstarrens sowie unter Last und weiteren Beanspruchungen können Risse mit unzulässiger Breite entstehen und Wasser führen. Sie können lokal mit ausgewählten Injektionsstoffen dauerhaft abgedichtet werden.Herstellungsbedingte Hohlräume und Fehlstellen im Betonquerschnitt treten in Häufigkeit und Ausmaß nur begrenzt auf. Teilweise sind Grenzflächen zwischen Bauteilen oder auch zwischen Beton und Bewehrung oder Einbauteilen von Hohlräumen betroffen. Sie lassen sich mit flächig ausgeführten Injektionsmaßnahmen abdichten.Injektionsmaßnahmen in Betonkonstruktionen sind bauartbedingt. Ihre erfolgreiche Anwendung erfordert baustoffliches Grundwissen und ausführungstechnische Kenntnisse. Regelwerke für die Instandsetzung werden in Deutschland von der europaweiten Harmonisierung beeinflusst. Die Berücksichtigung aktueller Verordnungen und Normen ist notwendig.Sealing of tears and cavities in waterproof concrete structuresExterior concrete components that have to fulfill a sealing function next to their load transfer, reinforcing or room‐enclosing function require accuracy in planning, execution and subsequent injection measures alike. To ensure functionality of watertight concrete structures, sealing injections that also guarantee protection from reinforcement corrosion are necessary.Constructive and executive measures as well as concrete technology cannot entirely prevent concrete from cracking. During curing, load or other exposition to stress, cracks with unacceptable width or even water bearing cracks may occur. Permanent sealing can be achieved using special and tailor made injection materials.Cavities and defects in concrete cross sections caused during the production process may appear only to a limited extent and are furthermore limited in frequency and dimension. Boundary layers either among structural parts or between concrete and reinforcement or mounting parts are partially affected by cavity building. Cavities may be sealed by laminar injection measures.Injection measures have to fit the concrete construction. Their successful execution requires knowledge about construction and execution. German rules and standards for refurbishing measurements are influenced significantly by European harmonization. Consideration of current standards and regulations is compulsory.
Why are most organelle genomes transmitted maternally?
Authors: Greiner Stephan , Sobanski Johanna , Bock Ralph 
Published: October 2014

AbstractWhy the DNA‐containing organelles, chloroplasts, and mitochondria, are inherited maternally is a long standing and unsolved question. However, recent years have seen a paradigm shift, in that the absoluteness of uniparental inheritance is increasingly questioned. Here, we review the field and propose a unifying model for organelle inheritance. We argue that the predominance of the maternal mode is a result of higher mutational load in the paternal gamete. Uniparental inheritance evolved from relaxed organelle inheritance patterns because it avoids the spread of selfish cytoplasmic elements. However, on evolutionary timescales, uniparentally inherited organelles are susceptible to mutational meltdown (Muller's ratchet). To prevent this, fall‐back to relaxed inheritance patterns occurs, allowing low levels of sexual organelle recombination. Since sexual organelle recombination is insufficient to mitigate the effects of selfish cytoplasmic elements, various mechanisms for uniparental inheritance then evolve again independently. Organelle inheritance must therefore be seen as an evolutionary unstable trait, with a strong general bias to the uniparental, maternal, mode.
Wie Bakterien unsere Abwehr überwinden
Authors: Kleiner Diethelm 
Published: October 2014

AbstractPathogene Bakterien überwinden unsere Abwehrmechanismen durch Ausbildung so genannter Virulenzfaktoren. Dabei handelt es sich in der Regel um toxische Proteine, aggressive Enzyme oder täuschende Oberflächenstrukturen. Deren Synthese ist energie‐ und materialaufwändig, daher werden Virulenzfaktoren erst gebildet, wenn das Zielgewebe erreicht ist. Dazu müssen Informationen über die Umgebung mit Hilfe spezifischer Proteine gesammelt werden. Weiterhin hängt der Erfolg einer Infektion zumindest in den ersten Stadien davon ab, dass eine genügend große Anzahl an Angreifern präsent ist, die dann wie ein multizellulärer Organismus kooperieren, in kurzer Zeit große Mengen an Virulenzfaktoren bilden und das Wirtsgewebe überrumpeln. Der Infektionsweg lässt sich meistens unterscheiden in: 1. Überwindung der ersten Schranken, 2. Adhäsion an das Zielgewebe, 3. Invasion, 4. Behebung des Eisenmangels, 5. Abwehr unserer Immunsysteme.
PID in der Reproduktionsmedizin
Authors: Hoppenstedt Werner 
Published: October 2014

AbstractPräimplantationsdiagnostik (PID) bezeichnet die Entnahme einer oder mehrerer Zellen eines extrakorporal erzeugten Embryos und dessen genetische Untersuchung vor deren Transfer in den Uterus. Seit der Änderung des Embryonenschutzgesetzes kann eine PID auch in Deutschland unter bestimmten Umständen rechtmäßig durchgeführt werden. Verschiedene diagnostische Methoden stehen zur Verfügung: die FISH für den Nachweis von maternalen Translokationen an Polkörpern, als momentan am meisten angewandte die Array‐CGH für ein Aneuploidiescreening und die Untersuchung auf Translokationen, sowie bei monogenen Erkrankungen die PCR mit anschließender Sequenzierung. In nicht allzu ferner Zukunft kann das Next Generation Sequencing alle vorher gehenden Methoden ersetzen.
Karl Ernst Ritter von Baer
Authors: Hübner Stephan M. 
Published: October 2014

AbstractDer einflussreiche baltische Universalgelehrte Karl Ernst von Baer (1792–1876) gilt als Begründer der vergleichenden Entwicklungsgeschichte. Als Professor in Königsberg beschäftigte sich der studierte Mediziner ausgiebig mit Fragen der Rekapitulation im Laufe der Embryonalentwicklung und entdeckte bei seinen Forschungen die Chorda dorsalis und die Eizelle der Säugetiere. Im Ruhestand wurde er zu einem der prominentesten Gegner Darwins. Von Baer begründete mehrere wissenschaftliche Grundregeln, Fachgesellschaften und Publikationsorgane.
Steinzeit‐Gene machen Tibeter höhentauglich
Authors: Brennicke Axel 
Published: October 2014

AbstractWir aus dem Tiefland haben in Tibet erhebliche Probleme mit der dünnen Luft auf über 4000 m Höhe, während die Tibeter an den niedrigen Sauerstoffgehalt angepasst sind. Bei ihnen ist nicht wie bei uns der Hämoglobingehalt stark erhöht, bei Tibetern ist das Gen für einen Transkriptionsfaktor verändert, der bei niedrigem Sauerstoffgehalt aktiviert wird. Die besonderen Polymorphismen in diesem Gen belegen, dass die Vorfahren der Tibeter sich mit dem Denisova‐Menschen vermischt haben, einer Menschengattung, die eng mit Neandertalern, aber auch mit Homo sapiens verwandt ist.
Differentiation of primary central nervous system lymphoma from high‐grade glioma and brain metastases using susceptibility‐weighted imaging
Authors: Ding Yaling , Xing Zhen , Liu Biying , Lin Xinjian , Cao Dairong 
Published: October 2014

AbstractBackground and PurposeConventional MRI is often difficult to distinguish between primary central nervous system lymphomas (PCNSLs), high‐grade gliomas and brain metastases due to the similarity of their appearance. The aim of this study was to investigate whether the susceptibility‐weighted imaging (SWI) has higher sensitivity than conventional MRI in detecting hemorrhage between PCNSLs, high‐grade gliomas and brain metastases, and can be used to differentiate the diagnosis between these tumors.MethodsThe number of lesions with hemorrhage was quantified by both the conventional MR imaging and SWI. The number of micro‐hemorrhage and vessels within lesions were counted on SWI.ResultsThe detection rate of hemorrhage on SWI was significantly higher than that on the conventional MR imaging. The intralesional hemorrhagic burden and the number of the vessels within lesions detected by SWI were significantly higher in high‐grade gliomas and brain metastases than those in PCNSLs. There was no significant difference in these two parameters between high‐grade gliomas and brain metastases. The best predictor to differentiate PCNSLs from high‐grade gliomas and brain metastases was intralesional vessel number that yielded the best ROC characteristics and highest classification accuracy.ConclusionsSWI is useful in differentiating of PCNSLs from high‐grade gliomas and brain metastases.
Covalent Inhibition of New Delhi Metallo‐β‐Lactamase‐1 (NDM‐1) by Cefaclor
Authors: Thomas Pei W. , Cammarata Michael , Brodbelt Jennifer S. , Fast Walter 
Published: October 2014

AbstractCovalent irreversible inhibitors can successfully treat antibiotic‐resistant infections by targeting serine β‐lactamases. However, this strategy is useless for New Delhi metallo‐β‐lactamase (NDM), which uses a non‐covalent catalytic mechanism and lacks an active‐site serine. Here, NDM‐1 was irreversibly inactivated by three β‐lactam substrates: cephalothin, moxalactam, and cefaclor, albeit at supratherapeutic doses (e.g., cefaclor KI=2.3±0.1 mM; kinact=0.024±0.001 min−1). Inactivation by cephalothin and moxalactam was mediated through Cys208. Inactivation by cefaclor proceeded through multiple pathways, in part mediated by Lys211. Use of a cefaclor metabolite enabled mass spectrometric identification of a +346.0735 Da covalent adduct on Lys211, and an inactivation mechanism is proposed. Lys211 was identified as a promising “handhold” for developing covalent NDM‐1 inhibitors and serves as a conceptual example for creating covalent inhibitors for enzymes with non‐covalent mechanisms.
Reactions of Pd and Pt Complexes with Molecular Oxygen
Authors: Scheuermann Margaret L. , Goldberg Karen I. 
Published: October 2014

AbstractKnowledge of exactly how metal complexes react with molecular oxygen is still limited and this has hampered efforts to develop catalysts for oxidation reactions using O2 as the oxidant and/or oxygen‐atom source. A better understanding of the reactions of different types of metal complexes with O2 will be of great utility in rational catalyst development. Reactions between molecular oxygen and Pd0–II and Pt0–IV complexes are reviewed here.
High‐Yield Synthesis of Amido‐Functionalized Polyoctahedral Oligomeric Silsesquioxanes by Using Acyl Chlorides
Authors: Janeta Mateusz , John Łukasz , Ejfler Jolanta , Szafert Sławomir 
Published: October 2014

AbstractHomosubstituted amido‐functionalized polyoctahedral oligomeric silsesquioxanes (POSS) have been synthesized by using acyl chlorides in high yields (ca. 95 %). The method proved to be superior over “conventional” syntheses applying carboxylic acids or acid anhydrides, which are much less efficient (ca. 60 % yield). A palette of aryl and alkyl groups has been used as side‐chains. The structures of the resulting amide‐POSS are supported by multinuclear 1H, 13C, 29Si NMR and FTIR spectroscopy and their full conversion into octasubstituted derivatives was confirmed using mass spectrometry. We also demonstrate that the functionalized silsesquioxanes with bulky organic side‐chains attached to cubic siloxane core form spherical‐like, well‐separated nanoparticles with a size of approximately 5 nm.
Supramolecular Fullerene Polymers and Networks Directed by Molecular Recognition between Calix[5]arene and C60
Authors: Hirao Takehiro , Tosaka Masatoshi , Yamago Shigeru , Haino Takeharu 
Published: October 2014

AbstractA biscalix[5]arene–C60 supramolecular structure was utilized for the development of supramolecular fullerene polymers. Di‐ and tritopic hosts were developed to generate the linear and network supramolecular polymers through the complexation of a dumbbell‐shaped fullerene. The molecular association between the hosts and the fullerene were carefully studied by using 1H NMR, UV/Vis absorption, and fluorescence spectroscopy. The formation of the supramolecular fullerene polymers and networks was confirmed by diffusion‐ordered 1H NMR spectroscopy (DOSY) and solution viscometry. Upon concentrating the mixtures of di‐ or tritopic hosts and dumbbell‐shaped fullerene in the range of 1.0–10 mmol L−1, the diffusion coefficients of the complexes decreased, and the solution viscosities increased, suggesting that large polymeric assemblies were formed in solution. Scanning electron microscopy (SEM) was used to image the supramolecular fullerene polymers and networks. Atomic force microscopy (AFM) provided insight into the morphology of the supramolecular polymers. A mixture of the homoditopic host and the fullerene resulted in fibers with a height of (1.4±0.1) nm and a width of (5.0±0.8) nm. Interdigitation of the alkyl side chains provided secondary interchain interactions that facilitated supramolecular organization. The homotritopic host generated the supramolecular networks with the dumbbell‐shaped fullerene. Honeycomb sheet‐like structures with many voids were found. The growth of the supramolecular polymers is evidently governed by the shape, dimension, and directionality of the monomers.
Intermolecular Radical Carbofluorination of Non‐activated Alkenes
Authors: Kindt Stephanie , Heinrich Markus R. 
Published: October 2014

AbstractThe Meerwein arylation has recently become an even more powerful tool for the functionalization of alkenes. Besides the attachment of an aryl group, radical reactions of this type allow the introduction of several different heteroatoms and a broad variety of alkenes are meanwhile tolerated as substrates. Closing a long‐standing gap of the methodology, this communication describes the first intermolecular Meerwein‐type carbofluorination. In metal‐free reactions, arylalkyl fluorides were obtained from arylhydrazines and alkenes with Selectfluor acting as oxidant and as radical fluorine source.
ChemInform Abstract: Synthesis and Crystal Structure of α‐ThTe3.
Authors: Prakash Jai , Ibers James A. 
Published: October 2014

AbstractThe title compound is obtained in an intended preparation of new compounds in the Ca—Th—Te system by solid state reaction of a 1:1:5 ratio of the respective elements (evacuated silica tubes, 1223 K, 96 h; 5 K/h cooling rate).
ChemInform Abstract: The Zintl Phase Cs7NaSi8 — From NMR Signal Line Shape Analysis and Quantum Mechanical Calculations to Chemical Bonding.
Authors: Pecher Oliver , Esters Marco , Goerne Arno , Mausolf Bernhard , Ormeci Alim , Haarmann Frank 
Published: October 2014

AbstractPowder samples of the title Zintl phase are obtained from a stoichiometric mixture of Cs4Si4 and Na4Si4 (Ta ampule, 500 °C, 14 d).
ChemInform Abstract: Crystal Structures of Hydrates of Simple Inorganic Salts. Part 3. Water‐Rich Aluminum Halide Hydrates: AlCl3·15H2O, AlBr3·15H2O, AlI3·15H2O, AlI3·17H2O and AlBr3·9H2O.
Authors: Schmidt Horst , Hennings Erik , Voigt Wolfgang 
Published: October 2014

AbstractThe crystal structures of the title compounds, crystallized from low‐temperature solutions, are determined by single crystal XRD.
ChemInform Abstract: Evidence of a Mixed Magnetic Phase in EuMgGe: A Semimetallic Zintl Compound with TiNiSi Structure Type.
Authors: Slabon Adam , Cuervo‐Reyes Eduardo , Niehaus Oliver , Winter Florian , Mensing Christian , Poettgen Rainer , Nesper Reinhard 
Published: October 2014

AbstractEuMgGe is prepared by melting and annealing the elements (Nb tube, 1.