bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fluoreszente Mimetika von CMP‐Neu5Ac sind hochaffine, zellgängige Polarisationssonden eukaryotischer und bakterieller Sialyltransferasen und inhibieren die zelluläre Sialylierung
Authors: Preidl Johannes J. , Gnanapragassam Vinayaga S. , Lisurek Michael , Saupe Jörn , Horstkorte Rüdiger , Rademann Jörg 
Published: April 2014

AbstractOligosaccharide der Glycolipide und Glycoproteine auf der äußeren Membran humaner Zellen tragen terminale Neuraminsäuren, die für die Zell‐Zell‐Erkennung und die Adhäsion von Zellen, Bakterien und Viruspartikeln verantwortlich sind. Die Synthese der Neuraminsäure‐tragenden Glycoside wird von intrazellulären Sialyltransferasen vollzogen. Daher könnte die chemische Manipulation der zellulären Sialylierung ein Weg zur Hemmung der Krebsentwicklung sowie von Entzündungen und Infektionen sein. Hier wird die Entwicklung und Anwendung der ersten nanomolaren fluoreszenten Inhibitoren von Sialyltransferasen beschrieben. Die erhaltenen Mimetika von Kohlenhydratnukleotiden erwiesen sich als Liganden der vier kommerziell erhältlichen und in Fluoreszenzpolarisations‐Assays getesteten eukaryotischen wie bakteriellen Sialyltransferasen. Darüber hinaus wurde beobachtet, dass die anionischen Mimetika schnell und effizient in Vesikeln in Zellen eindrangen und zu den kernnahen Organellen von CHO‐Zellen wanderten. Die neuen Verbindungen inhibieren die zelluläre Sialylierung in zwei Zelllinien und eröffnen neue Perspektiven zur Untersuchung zellulärer Sialylierung.
Asymmetrische Katalyse im Nanomaßstab: die organokatalytische Synthese von Helicenen
Authors: Kötzner Lisa , Webber Matthew J. , Martínez Alberto , De Fusco Claudia , List Benjamin 
Published: April 2014

AbstractEs wird über die erste asymmetrische organokatalytische Synthese von Helicenen berichtet. Eine neue SPINOL‐abgeleitete Phosphorsäure mit ausgedehnten π‐Substituenten katalysiert die asymmetrische Synthese von Helicenen über eine enantioselektive Fischer‐Indolisierung. Eine Vielzahl von Azahelicenen und Diazahelicenen konnte auf diese Weise mit guten bis sehr guten Ausbeuten und Enantioselektivitäten erhalten werden.
Three‐Dimensional Ordered Assembly of Thin‐Shell Au/TiO2 Hollow Nanospheres for Enhanced Visible‐Light‐Driven Photocatalysis
Authors: Dinh Cao‐Thang , Yen Hoang , Kleitz Freddy , Do Trong‐On 
Published: April 2014

AbstractAn Au/TiO2 nanostructure was constructed to obtain a highly efficient visible‐light‐driven photocatalyst. The design was based on a three‐dimensional ordered assembly of thin‐shell Au/TiO2 hollow nanospheres (Au/TiO2‐3 DHNSs). The designed photocatalysts exhibit not only a very high surface area but also photonic behavior and multiple light scattering, which significantly enhances visible‐light absorption. Thus Au/TiO2‐3 DHNSs exhibit a visible‐light‐driven photocatalytic activity that is several times higher than conventional Au/TiO2 nanopowders.
Live‐Cell Quantitative Imaging of Proteome Degradation by Stimulated Raman Scattering
Authors: Shen Yihui , Xu Fang , Wei Lu , Hu Fanghao , Min Wei 
Published: April 2014

AbstractProtein degradation is a regulatory process essential to cell viability and its dysfunction is implicated in many diseases, such as aging and neurodegeneration. In this report, stimulated Raman scattering microscopy coupled with metabolic labeling with 13C‐phenylalanine is used to visualize protein degradation in living cells with subcellular resolution. We choose the ring breathing modes of endogenous 12C‐phenylalanine and incorporated 13C‐phenylalanine as protein markers for the original and nascent proteomes, respectively, and the decay of the former wasquantified through 12C/(12C+13C) ratio maps. We demonstrate time‐dependent imaging of proteomic degradation in mammalian cells under steady‐state conditions and various perturbations, including oxidative stress, cell differentiation, and huntingtin protein aggregation.
Asymmetric Catalysis on the Nanoscale: The Organocatalytic Approach to Helicenes
Authors: Kötzner Lisa , Webber Matthew J. , Martínez Alberto , De Fusco Claudia , List Benjamin 
Published: April 2014

AbstractThe first asymmetric organocatalytic synthesis of helicenes is reported. A novel SPINOL‐derived phosphoric acid, bearing extended π‐substituents, catalyzes the asymmetric synthesis of helicenes through an enantioselective Fischer indole reaction. A variety of azahelicenes and diazahelicenes could be obtained with good to excellent yields and enantioselectivities.
Large Zero‐Field Splittings of the Ground Spin State Arising from Antisymmetric Exchange Effects in Heterometallic Triangles
Authors: Magee Samantha A. , Sproules Stephen , Barra Anne‐Laure , Timco Grigore A. , Chilton Nicholas F. , Collison David , Winpenny Richard E. P. , McInnes Eric J. L. 
Published: April 2014

Abstract[Ru2Mn(O)(O2CtBu)6(py)3] has an S=5/2 ground state with a very large zero‐field splitting (ZFS) of D=2.9 cm−1, as characterized by EPR spectroscopy at 4–330 GHz. This is far too large to be due to the MnII ion (D <0.2 cm−1), as shown from the {Fe2Mn} analogue, but can be modeled by antisymmetric exchange effects.
Quantitative chemical composition determination and thermal analysis for typical biomass ashes in China
Authors: Wang Wenlong , Liu Xin , Zheng Yanli 
Published: April 2014

ABSTRACTFor better use of biomass resources, a complete understanding of the chemical compositions for the biomass ashes is important. By the joint adoption of several analysis tools, the ashes of four typical biomass resources in rural areas of north China, i.e. corn stalk, wheat stalk, cotton branch, and poplar, were studied. It was found that after heating for 24 h at 450 and 850 °C, the biomass ashes exhibited quite different chemical and mineral compositions. At 450 °C, potassium salts (KCl, K2SO4, or K2CO3), carbonates, phosphates, and oxides (SiO2 and MgO) were the primary mineral phases; however, at 850 °C, all of the KCl and CaCO3 broke down, and the primary mineral phases became silicates, phosphates, and undecomposed potassium salts. The detailed mineral compositions of the biomass ashes were determined by carefully balancing the X‐ray fluorescence spectrometry and X‐ray diffraction results, which were then well confirmed by the thermal analysis via FactSage modeling and thermogravimetric analyses. The complete understanding of the chemical compositions and thermal properties of the biomass ashes will aid in their utilization or, in some cases, enable the avoidance of their negative effects. In addition, the joint analysis method here can be referred in the determination of mineral contents of any other biomass ash. © 2014 Curtin University of Technology and John Wiley & Sons, Ltd.
Donor–Acceptor‐Type Copolymers Based on a Naphtho[1,2‐c:5,6‐c]bis(1,2,5‐thiadiazole) Scaffold for High‐Efficiency Polymer Solar Cells
Authors: Liu Li‐Qian , Zhang Gui‐Chuan , Liu Peng , Zhang Jie , Dong Sheng , Wang Ming , Ma Yu‐Guang , Yip Hin‐Lap , Huang Fei 
Published: April 2014

AbstractFour donor–acceptor‐type low‐bandgap conjugated polymers based on a naphtho[1,2‐c:5,6‐c]bis(1,2,5‐thiadiazole) (NT) acceptor and different donors bridged by a bithiophene spacer have been synthesized through Suzuki or Stille polymerization reactions. Fluorene (F), carbazole (Cz), alkylidene fluorene (AF), and benzodithiophene (BDT) were selected as the donor units to produce a series of new conjugated polymers. Owing to the different electron‐donating ability of the donor units, the energy levels, absorption spectra, bandgaps, and carrier mobilities of the resulting polymers were systematically tuned. Bulk‐heterojunction‐type polymer solar cells based on the new polymers and [6,6]‐phenyl‐C61‐butyric acid methyl ester (PC61BM) or [6,6]‐phenyl‐C71‐butyric acid methyl ester (PC71BM) were investigated and all of the devices exhibited good photovoltaic performance, with power‐conversion efficiencies (PCEs) over 3 %. The best device performance was achieved by PF‐C12NT, with an open‐circuit voltage (Voc) of 0.87 V, a short‐circuit current density (Jsc) of 12.19 mA cm−2, a fill factor (FF) of 61.36 %, and a PCE of 6.51 % under simulated sunlight (100 mW cm−2, AM 1.5G).
Neue Temperatur‐Korrekturfaktoren für erdberührte Bauteile bei Energieeffizienzberechnungen
Authors: Schild Kai 
Published: April 2014

AbstractTransmissionswärmeverluste über erdberührte Bauteile werden allgemein gemäß der internationalen Norm DIN EN ISO 13370 berechnet. Als Alternative und Vereinfachung werden in DIN V 4108‐6 und DIN V 18599‐2 Temperatur‐Korrekturfaktoren eingeführt. Beide Rechenansätze führen oft zu erheblich voneinander abweichenden Ergebnissen. Dies führt entweder zu einer Unterschätzung der Wärmeverluste oder zu unwirtschaftlichen Kompensationsmaßnahmen durch dickere Wärmedämmungen. In diesem Artikel werden die Ergebnisse einer Parameterstudie gezeigt, die zur Quantifizierung der Größenordnung der Abweichungen durchgeführt wurde. Ferner wird eine Tabelle mit neuen Temperatur‐Korrekturfaktoren gezeigt, die für die Nutzung bei Energieeffizienzberechnungen vorgeschlagen werden.New temperature correction factors for ground coupled building parts with energy performance calculations. Transmission heat losses for building elements in contact with the ground are calculated according to the international standard DIN EN ISO 13370. As an alternative and simplification DIN V 4108‐6 and DIN V 18599 introduce thermal correction factors. The result of both approaches often vary a lot. This could lead to an underestimation of the heat loss as well as to uneconomic overcompensations by insulation measures. In this article the results of a parameter study are shown, that has been carried out to quantify the size of the deviations. Furthermore new temperature correction factors are shown, that are recommended for energy performance calculations.
Trommeln, Singen oder Sprechen – der Unterrichtsraum spielt immer mit!
Authors: Fuchs Helmut V. 
Published: April 2014

AbstractDas Bewusstsein für raumakustische Missstände in unseren Bildungseinrichtungen steigt allmählich, und die Bereitschaft zu nachhaltigen Sanierungen wächst langsam, auch auf Druck der Betroffenen und von Fördervereinen. Weil die finanziellen Mittel für die eigentlich dringend notwendigen baulichen Maßnahmen in Kitas, Schulen und Hochschulen ihren öffentlichen Trägern aber auf absehbare Zeit nicht zur Verfügung stehen, ist man mancherorts bereit, privat zu investieren. Nachdem so im letzten Jahr ein Ganztageshort in einer Grundschule mustergültig streng nach DIN 18041 saniert werden konnte [1], wird hier über eine ähnlich vorbildliche Installation von preiswerten Kanten‐Absorbern in einem Musikraum einer Berliner Oberschule berichtet. Diese gemeinnützigen Initiativen regen mit ihrem Vorbildcharakter die Verantwortlichen der jeweiligen Bezirke bereits zur Nachahmung an.Drumming, singing, or speaking – the tuition room will always interfere! – A contribution to the International Noise Awareness Day 2014. Severe deficits in the room acoustics of our educational facilities become more and more obvious, and the readiness for sustainable restorations increases slowly on pressure from those concerned. As financial resources for building measures urgently needed in kindergartens, schools, and universities will not become available in due course, one is ready, in places, to privately invest in them. After last year a full‐day nursery of a primary school could be restored exemplarily and strictly according to DIN 18041, a similarly representative installation of praiseworthy compact edge absorbers in a music classroom of a secondary school in Berlin is reported here. These charity initiatives with their prototype character have already motivated those responsible in the respective districts to imitative actions.
Circadiane Uhren und Energiemetabolismus
Authors: Oster Henrik 
Published: April 2014

AbstractGenetisch codierte innere Uhren steuern Physiologie und Verhalten im 24h‐Takt. Ein zentraler Schrittmacher im Nucleus suprachiasmaticus synchronisiert periphere Uhren in allen Geweben untereinander und mit dem äußeren Tag‐Nacht‐Rhythmus. Eine wichtige Funktion der circadianen Uhr ist die Regulation des Energiestoffwechsels über die rhythmische Aktivierung von gewebsspezifischen uhrenkontrollierten Genen. In der Leber sind besonders der Glucose‐ und Fettstoffwechsel, in den Adipozyten die Fettsäurefreisetzung und die Sekretion von Adipokinen auf diese Weise reguliert. Störungen der circadianen Rhythmik, z. B. bei Schichtarbeit, begünstigen die Entwicklung von Erkrankungen des Energiestoffwechsels wie Adipositas und Typ‐2‐Diabetes.
Amborella trichopoda – das Schnabeltier unter den Pflanzen
Authors: Brennicke Axel 
Published: April 2014

AbstractVerschiedene Merkmale belegen, dass die buschigen Pflanzen von Amborella trichopoda eine der frühesten Abspaltungen von der Linie der bedecktsamigen Blütenpflanzen sind. Diese in Neukaledonien endemische Pflanze ist die einzige Schwesterlinie zu allen anderen Angiospermen und damit von großer Bedeutung für das Verständnis der Evolution dieser so erfolgreichen Pflanzen. Die jetzt analysierte Sequenz des Genoms bestätigt die Sonderstellung von Amborella und zeigt, wie sich Gene z.B. für die Entwicklung der Blüten herausbildeten.
Farbensehen mit den Augen eines Heuschrecken‐Krebses
Authors: Kronberg Inge 
Published: April 2014

AbstractHeuschreckenkrebse (Stomatopoda) besitzen die wohl kompliziertesten Komplexaugen im Tierreich. Experimente zeigen, dass das Farbensehen bei ihnen ganz anders funktioniert als bei uns Menschen – wie von einer anderen Welt.
Blütenbildung mit epigenetischer Zeitschaltuhr
Authors: Sander Johannes 
Published: April 2014

AbstractBlütenmeristeme erschöpfen sich bei der Bildung der Blüte. Doch dabei kommt es auf das richtige Timing an, denn solange noch Blütenorgane gebildet werden müssen, wird auch das Meristem noch benötigt. Dementsprechend müssen bestimmte Prozesse zeitverzögert ablaufen.
Ein Instrument der Qualitätssicherung: die Validierung
Authors: Hauk Andrea 
Published: April 2014

AbstractSpätestens wenn eine Akkreditierung bzw. Zulassung ins Haus steht, müssen sich Anwender mit der Validierung ihrer Verfahren, Methoden und Prozesse auseinandersetzen. Validiert wird aber auch, wenn ein Produkt, beispielsweise ein analytischer Test, vor der Markteinführung steht. Hier erfahren Sie in aller Kürze das Wichtigste zum “mitreden”.
Model Molecules with Oxygenated Groups Catalyze the Reduction of Nitrobenzene: Insight into Carbocatalysis
Authors: Wu Shuchang , Wen Guodong , Liu Xiumei , Zhong Bingwei , Su Dang Sheng 
Published: April 2014

AbstractThe role of different oxygen functional groups on a carbon catalyst was studied in the reduction of nitrobenzene by using a series of model molecules. The carbonyl and hydroxyl groups played important roles, which may be ascribed to their ability to activate hydrazine. In comparison, the ester, ether, and lactone groups seemed to be inactive, whereas the carboxylic group had a negative effect. The reaction occurred most likely through a direct route, during which nitrosobenzene may be converted directly into aniline.
On the Frontier Between Nucleophilic Aromatic Substitution and Catalysis
Authors: Pichette Drapeau Martin , Ollevier Thierry , Taillefer Marc 
Published: April 2014

AbstractA study on the arylation of heteroatom nucleophiles by using activated haloarenes, with or without metal catalysts, is reported. A discussion concerning the involvement of traces of metals is presented, supported by an unexpected ''ligand'' effect in the absence of added metal catalysts. We believe that the frontier between nucleophilic aromatic substitution and catalysis will likely prove to be much harder to delimit than is generally thought.
Stabilisation of 2,6‐Diarylpyridinium Cation by Through‐Space Polar–π Interactions
Authors: Padial Joan Simó , de Gelder René , Fonseca Guerra Célia , Bickelhaupt F. Matthias , Mecinović Jasmin 
Published: April 2014

AbstractThe through‐space polar–π interactions between pyridinium ion and the adjacent aromatic rings in 2,6‐diarylpyridines affect the pKa values. Hammett analysis illustrates that the basicity of pyridines correlates well with the sigma values of the substituents at the para position of the flanking aryl rings.
Probing Weak Intermolecular Interactions by Using the Invariom Approach: A Comparative Study ofs‐Tetrazine
Authors: Nelyubina Yulia V. , Korlyukov Alexander A. , Lyssenko Konstantin A. 
Published: April 2014

AbstractA comparative study of chemical bonding peculiarities in 1,2,4,5‐tetrazine was carried out to test the performance of a recently developed invariom approach against a conventional charge density analysis of high‐resolution X‐ray diffraction data and quantum chemical calculations within the plane‐wave functional theory. The amazing similarity between the intermolecular features thus obtained for this van der Waals crystal showed the invariom approximation to now emerge as a fast and convenient way towards reliable description of weak intermolecular interactions.
Ureidopeptide‐Based Brønsted Bases: Design, Synthesis and Application to the Catalytic Enantioselective Synthesis of β‐Amino Nitriles from (Arylsulfonyl)acetonitriles
Authors: Diosdado Saioa , López Rosa , Palomo Claudio 
Published: April 2014

AbstractThe addition of cyanoalkyl moieties to imines is a very attractive method for the preparation of β‐amino nitriles. We present a highly efficient organocatalytic methodology for the stereoselective synthesis of β‐amino nitriles, in which the key to success is the use of ureidopeptide‐based Brønsted base catalysts in combination with (arylsulfonyl)acetonitriles as synthetic equivalents of the acetonitrile anion. The method gives access to a variety of β‐amino nitriles with good yields and excellent enantioselectivities, and broadens the stereoselective Mannich‐type methodologies available for their synthesis.
A Glutathione‐Activated Phthalocyanine‐Based Photosensitizer for Photodynamic Therapy
Authors: He Hui , Lo Pui‐Chi , Ng Dennis K. P. 
Published: April 2014

AbstractA zinc(II) phthalocyanine substituted with a 2,4‐dinitrobenzenesulfonate group has been prepared. Its fluorescence emission and reactive oxygen species generation can be greatly enhanced by glutathione in phosphate‐buffered saline and inside MCF‐7 cells. This compound thus functions as a highly efficient molecular‐based activatable photosensitizer.
Asymmetric Allylation of Ketones and Subsequent Tandem Reactions Catalyzed by a Novel Polymer‐Supported Titanium–BINOLate Complex
Authors: Yadav Jagjit , Stanton Gretchen R. , Fan Xinyuan , Robinson Jerome R. , Schelter Eric J. , Walsh Patrick J. , Pericas Miquel A. 
Published: April 2014

AbstractBy using a novel, simple, and convenient synthetic route, enantiopure 6‐ethynyl‐BINOL (BINOL=1,1‐binaphthol) was synthesized and anchored to an azidomethylpolystyrene resin through a copper‐catalyzed alkyne–azide cycloaddition (CuAAC) reaction. The polystyrene (PS)‐supported BINOL ligand was converted into its diisopropoxytitanium derivative in situ and used as a heterogeneous catalyst in the asymmetric allylation of ketones. The catalyst showed good activity and excellent enantioselectivity, typically matching the results obtained in the corresponding homogeneous reaction. The allylation reaction mixture could be submitted to epoxidation by simple treatment with tert‐butyl hydroperoxide (TBHP), and the tandem asymmetric allylation epoxidation process led to a highly enantioenriched epoxy alcohol with two adjacent quaternary centers as a single diastereomer. A tandem asymmetric allylation/Pauson–Khand reaction was also performed, involving simple treatment of the allylation reaction mixture with Co2(CO)8/N‐methyl morpholine N‐oxide. This cascade process resulted in the formation of two diastereomeric tricyclic enones in high yields and enantioselectivities.
From the Lindlar Catalyst to Supported Ligand‐Modified Palladium Nanoparticles: Selectivity Patterns and Accessibility Constraints in the Continuous‐Flow Three‐Phase Hydrogenation of Acetylenic Compounds
Authors: Vilé Gianvito , Almora‐Barrios Neyvis , Mitchell Sharon , López Núria , Pérez‐Ramírez Javier 
Published: April 2014

AbstractInvited for the cover of this issue are the groups of Prof. Javier Pérez‐Ramírez at ETH Zurich, Switzerland, and Prof. Núria López at the Institute of Chemical Research of Catalonia (ICIQ), Spain. The cover illustrates major evolutionary changes in the design of palladium catalysts for alkyne semi‐hydrogenation. Read the full text of the article at 10.1002/chem.201304795.
Anionic Bipyridyl Ligands for Applications in Metallasupramolecular Chemistry
Authors: Pascu Mirela , Marmier Mathieu , Schouwey Clément , Scopelliti Rosario , Holstein Julian J. , Bricogne Gérard , Severin Kay 
Published: April 2014

AbstractInvited for the cover of this issue is the group of Kay Severin at the EPFL in Switzerland (a picture of the campus is shown above; photo: Alain Herzog, EPFL) and collaborators from Global Phasing in Cambridge. The image refers to the (chemical) advantage of being negative. Read the full text of the article at 10.1002/chem.201400285.
Aqueous Self‐Assembly and Cation Selectivity of Cobaltabisdicarbollide Dianionic Dumbbells
Authors: Tarrés Màrius , Viñas Clara , González‐Cardoso Patricia , Hänninen Mikko M. , Sillanpää Reijo , Ďorďovič Vladimír , Uchman Mariusz , Teixidor Francesc , Matějíček Pavel 
Published: April 2014

AbstractThe anion [3,3′‐Co(C2B9H11)2]− ([COSAN]−) produces aggregates in water. These aggregates are interpreted to be the result of CH⋅⋅⋅HB interactions. It is possible to generate aggregates even after the incorporation of additional functional groups into the [COSAN]− units. The approach is to join two [COSAN]− anions by a linker that can adapt itself to act as a crown ether. The linker has been chosen to have six oxygen atoms, which is the ideal number for K+ selectivity in crown ethers. The linker binds the alkaline metal ions with different affinities; thus showing a distinct degree of selectivity. The highest affinity is shown towards K+ from a mixture containing Li+, Na+, K+, Rb+ and Cs+; this can be indicative of pseudo‐crown ether performance of the dumbbell. One interesting possibility is that the [COSAN]− anions at the two ends of the linker can act as a hook‐and‐loop fastener to close the ring. This facet is intriguing and deserves further consideration for possible applications. The distinct affinity towards alkaline metal ions is corroborated by solubility studies and isothermal calorimetry thermograms. Furthermore, cryoTEM micrographs, along with light scattering results, reveal the existence of small self‐assemblies and compact nanostructures ranging from spheres to single‐/multi‐layer vesicles in aqueous solutions. The studies reported herein show that these dumbbells can have different appearances, either as molecules or aggregates, in water or lipophilic phases; this offers a distinct model as drug carriers.
Oxidative Addition of Water and Methanol to a Dicationic Trivalent Phosphorus Centre
Authors: Tay Madelyn Qin Yi , Lu Yunpeng , Ganguly Rakesh , Vidović Dragoslav 
Published: April 2014

AbstractOur recently synthesised phosphorus dication is observed to activate water (and methanol) under reactions conditions atypical for other systems containing a non‐metal centre. This particular activation described as oxidative addition is quite rare and has been reserved exclusively for a couple of metal‐based compounds.
An Easy Route to (Hetero)arylboronic Acids
Authors: Erb William , Hellal Akila , Albini Mathieu , Rouden Jacques , Blanchet Jérôme 
Published: April 2014

AbstractAn unprecedented spontaneous reactivity between diazonium salts and diboronic acid has been unveiled, leading to a versatile arylboronic acid synthesis directly from (hetero)arylamines. This fast reaction (35 min overall) tolerates a wide range of functional groups and is carried out under very mild conditions. The radical nature of the reaction mechanism has been investigated.