bluuebunny/crossref_metadata_2025_split huggingface dataset:
Durch Polymerase‐Kettenreaktion erzeugte DNA‐Peptid‐Netzwerke als künstliche extrazelluläre Matrix
Authors: Finke Alexander , Bußkamp Holger , Manea Marilena , Marx Andreas 
Published: July 2016

AbstractZellproliferation und Zelldifferenzierung in multizellulären Organismen werden unter anderem durch Signale der extrazellulären Matrix reguliert. Die Möglichkeit, eine extrazelluläre Matrix nachzuahmen, um bestimmte Zelltypen spezifisch zu erkennen, ist ein zentrales Konzept der Gewebezüchtung. Wir präsentieren ein neues DNA‐basiertes Material mit Zellbindungseigenschaften, das durch kovalent gebundene DNA als Primer in einer PCR erzeugt wird. Mittels Klick‐Chemie werden diese Primer mit dem cyclischen Peptid c(RGDfK) funktionalisiert. Es ist bekannt, dass c(RGDfK) vorwiegend an αvβ3‐Integrine bindet, die beispielsweise auf Endothelzellen und Fibroblasten zu finden sind. Als kovalente Beschichtung auf Oberflächen zeigt dieses DNA‐basierte Material in seinem unfunktionalisierten Zustand zellabweisende Eigenschaften. Nach Funktionalisierung mit c(RGDfK) entsteht Adhäsivität zu bestimmten Zellen. Solche Zellen bleiben dabei lebensfähig und können bei milden Bedingungen durch eine Behandlung mit DNase I abgelöst werden.
C−H Coupling Reactions Directed by Sulfoxides: Teaching an Old Functional Group New Tricks
Authors: Pulis Alexander P. , Procter David J. 
Published: July 2016

AbstractSulfoxides are classical functional groups for directing the stoichiometric metalation and functionalization of C−H bonds. In recent times, sulfoxides have been given a new lease on life owing to the development of modern synthetic methods that have arisen because of their unique reactivity. They have recently been used in catalytic C−H activation proceeding via coordination of an internal sulfoxide to a metal or through the action of an external sulfoxide ligand. Furthermore, sulfoxides are able to capture nucleophiles and electrophiles to give sulfonium salts, which subsequently enable the formation of C−C bonds at the expense of C−H bonds. This Review summarizes a renaissance period in the application of sulfoxides arising from their versatility in directing C−H functionalization.
On‐Surface Domino Reactions: Glaser Coupling and Dehydrogenative Coupling of a Biscarboxylic Acid To Form Polymeric Bisacylperoxides
Authors: Held Philipp Alexander , Gao Hong‐Ying , Liu Lacheng , Mück‐Lichtenfeld Christian , Timmer Alexander , Mönig Harry , Barton Dennis , Neugebauer Johannes , Fuchs Harald , Studer Armido 
Published: July 2016

AbstractHerein we report the on‐surface oxidative homocoupling of 6,6′‐(1,4‐buta‐1,3‐diynyl)bis(2‐naphthoic acid) (BDNA) via bisacylperoxide formation on different Au substrates. By using this unprecedented dehydrogenative polymerization of a biscarboxylic acid, linear poly‐BDNA with a chain length of over 100 nm was prepared. It is shown that the monomer BDNA can be prepared in situ at the surface via on‐surface Glaser coupling of 6‐ethynyl‐2‐naphthoic acid (ENA). Under the Glaser coupling conditions, BDNA directly undergoes polymerization to give the polymeric peroxide (poly‐BDNA) representing a first example of an on‐surface domino reaction. It is shown that the reaction outcome varies as a function of surface topography (Au(111) or Au(100)) and also of the surface coverage, to give branched polymers, linear polymers, or 2D metal–organic networks.
Organotrisulfide: A High Capacity Cathode Material for Rechargeable Lithium Batteries
Authors: Wu Min , Cui Yi , Bhargav Amruth , Losovyj Yaroslav , Siegel Amanda , Agarwal Mangilal , Ma Ying , Fu Yongzhu 
Published: July 2016

AbstractAn organotrisulfide (RSSSR, R is an organic group) has three sulfur atoms which could be involved in multi‐electron reduction reactions; therefore it is a promising electrode material for batteries. Herein, we use dimethyl trisulfide (DMTS) as a model compound to study its redox reactions in rechargeable lithium batteries. With the aid of XRD, XPS, and GC‐MS analysis, we confirm DMTS could undergo almost a 4 e− reduction process in a complete discharge to 1.0 V. The discharge products are primarily LiSCH3 and Li2S. The lithium cell with DMTS catholyte delivers an initial specific capacity of 720 mAh g−1DMTS and retains 82 % of the capacity over 50 cycles at C/10 rate. When the electrolyte/DMTS ratio is 3:1 mL g−1, the reversible specific energy for the cell including electrolyte can be 229 Wh kg−1. This study shows organotrisulfide is a promising high‐capacity cathode material for high‐energy rechargeable lithium batteries.
Divergent Coordination Chemistry: Parallel Synthesis of [2×2] Iron(II) Grid‐Complex Tauto‐Conformers
Authors: Schäfer Bernhard , Greisch Jean‐François , Faus Isabelle , Bodenstein Tilmann , Šalitroš Ivan , Fuhr Olaf , Fink Karin , Schünemann Volker , Kappes Manfred M. , Ruben Mario 
Published: July 2016

AbstractThe coordination of iron(II) ions by a homoditopic ligand L with two tridentate chelates leads to the tautomerism‐driven emergence of complexity, with isomeric tetramers and trimers as the coordination products. The structures of the two dominant [FeII4L4]8+ complexes were determined by X‐ray diffraction, and the distinctness of the products was confirmed by ion‐mobility mass spectrometry. Moreover, these two isomers display contrasting magnetic properties (FeII spin crossover vs. a blocked FeII high‐spin state). These results demonstrate how the coordination of a metal ion to a ligand that can undergo tautomerization can increase, at a higher hierarchical level, complexity, here expressed by the formation of isomeric molecular assemblies with distinct physical properties. Such results are of importance for improving our understanding of the emergence of complexity in chemistry and biology.
A Dinitrogen Dicopper(I) Complex via a Mixed‐Valence Dicopper Hydride
Authors: Zhang Shiyu , Fallah Hengameh , Gardner Evan J. , Kundu Subrata , Bertke Jeffery A. , Cundari Thomas R. , Warren Timothy H. 
Published: July 2016

AbstractLow‐temperature reaction of the tris(pyrazolyl)borate copper(II) hydroxide [iPr2TpCu]2(μ‐OH)2 with triphenylsilane under a dinitrogen atmosphere gives the bridging dinitrogen complex [iPr2TpCu]2(μ‐1,2‐N2) (3). X‐ray crystallography reveals an only slightly activated N2 ligand (N‐N: 1.111(6) Å) that bridges between two monovalent iPr2TpCu fragments. While DFT studies of mono‐ and dinuclear copper dinitrogen complexes suggest weak π‐backbonding between the d10 CuI centers and the N2 ligand, they reveal a degree of cooperativity in the dinuclear Cu‐N2‐Cu interaction. Addition of MeCN, CNAr2,6‐Me, or O2 to 3 releases N2 with formation of iPr2TpCu(L) (L=NCMe, CNAr2,6‐Me2) or [iPr2TpCu]2(μ‐η2:η2‐O2) (1). Addition of triphenylsilane to [iPr2TpCu]2(μ‐OH)2 in pentane allows isolation of a key intermediate [iPr2TpCu]2(μ‐H) (5). Although 5 thermally decays under N2 to give 3, it reduces unsaturated substrates, such as CO and HC≡CPh to HC(O)H and H2C=CHPh, respectively.
Structural Interpretation of Metastable States in Myoglobin–NO
Authors: Soloviov Maksym , Das Akshaya K. , Meuwly Markus 
Published: July 2016

AbstractNitric oxide binding and unbinding from myoglobin (Mb) is central to the function of the protein. By using reactive molecular dynamics (MD) simulations, the dynamics following NO dissociation were characterized in both time and space. Ligand rebinding can be described by two processes on the 10 ps and 100 ps timescale, which agrees with recent optical and X‐ray absorption experiments. Explicitly including the iron out‐of‐plane (Fe‐oop) coordinate is essential for a meaningful interpretation of the data. The proposed existence of an “Fe‐oop/NO‐bound” state is confirmed and assigned to NO at a distance of approximately 3 Å away from the iron atom. However, calculated XANES spectra suggest that it is diffcult to distinguish between NO close to the heme‐Fe and positions further away in the primary site. Another elusive state, with Fe−ON coordination, was not observed experimentally because it is masked by the energetically more favorable but dissociative 4A state in this region, which makes the Fe−ON local minimum unobservable in wild‐type Mb. However, suitable active‐site mutations may stabilize this state.
Designer Extracellular Matrix Based on DNA–Peptide Networks Generated by Polymerase Chain Reaction
Authors: Finke Alexander , Bußkamp Holger , Manea Marilena , Marx Andreas 
Published: July 2016

AbstractCell proliferation and differentiation in multicellular organisms are partially regulated by signaling from the extracellular matrix. The ability to mimic an extracellular matrix would allow particular cell types to be specifically recognized, which is central to tissue engineering. We present a new functional DNA‐based material with cell‐adhesion properties. It is generated by using covalently branched DNA as primers in PCR. These primers were functionalized by click chemistry with the cyclic peptide c(RGDfK), a peptide that is known to predominantly bind to αvβ3 integrins, which are found on endothelial cells and fibroblasts, for example. As a covalent coating of surfaces, this DNA‐based material shows cell‐repellent properties in its unfunctionalized state and gains adhesiveness towards specific target cells when functionalized with c(RGDfK). These cells remain viable and can be released under mild conditions by DNase I treatment.
A novel flame retardant UV‐curable vinyl ester resin monomer based on industrial dipentene: Preparation, characterization, and properties
Authors: Mao Wei , Li Shouhai , Li Mei , Yang Xuejuan , Song Jian , Wang Mei , Xia Jianling , Huang Kun 
Published: July 2016

ABSTRACTA novel bio‐based and flame‐retardant UV‐curable vinyl ester resin (VER) monomer named Diglycidyl ester of maleinized dipentene modified with dibutyphosphate and methacrylic anhydride (MDDMD) was synthesized from industrial dipentene via Diels‐Alder reaction, glycidylation, epoxy ring‐opening reaction, and esterification. Its chemical structures were characterized by Fourier transform infrared (FTIR) analysis and proton nuclear magnetic resonance (1H‐NMR). In order to improve its flexibility, we prepared a series of copolymers under UV light radiation by mixing it with certain proportions of poly(ethylene glycol) dimethacrylate‐200 (PEGDMA‐200) which contained flexible groups. Their tensile property, curing degrees (CD), hardness, limiting oxygen index (LOI), dynamic mechanical thermal properties, and thermostability were all investigated. The cured mixed resins have a relatively high tensile strength of 10.05 MPa and curing degrees up to 92.5%. Both hardness (range: 50 to 23 HD) and LOI (range: 22.8% to 24.4%) of cured resins are improved with the increase of MDDMD content. Dynamic mechanical analysis (DMA) shows that their glass transition temperatures rise with the increase of MDDMD content. Thermogravimetric analysis (TGA) shows that the thermal stability of cured resins is enhanced with the increase of PEGDMA‐200 content, as the main thermal initial decomposition temperatures are all above 260 °C and char yield at 800 °C are above 18.10%. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44084.
Electrical behavior of dual‐morphology polyaniline
Authors: Kumar Anil , Jangir Lokesh Kumar , Kumari Yogita , Kumar Manoj , Kumar Vinod , Awasthi Kamlendra 
Published: July 2016

ABSTRACTAn attempt was taken to synthesize two types of polyaniline (PANI) with and without solvent followed by drying in air and vacuum oven conditions resulting different morphologies. The PANIs were prepared by chemical oxidative polymerization and studied with respect to their morphological features. Scanning electron microscopy, thermogravimetric analysis, X‐ray diffractometry, Fourier transform infrared spectroscopy, and ultraviolet–visible spectroscopy techniques were used for the characterization studies. The PANI synthesized with a solvent had a mixed morphology (fibrillar and granular), whereas PANI synthesized without a solvent had only a granular morphology. The direct‐current electrical conductivities of the samples were evaluated with an electrometer. We observed that the PANIs with mixed morphology (with solvent) were more electrically conducting than those with a single morphology (without solvent). On drying in vacuo, the conductivity of PANI decreased from 3.3 × 10−2 to 0.3 × 10−2 S/cm with solvent treatment, whereas it decreased from 0.1 × 10−2 to 0.3 × 10−3 S/cm without solvent treatment. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44091.
Morphological and nanomechanical characterization of anisotropic interfacial characteristic regions in CF/PA6 composites at different cooling rates
Authors: Li H. , Zhang Y. , Bai G. , Zhang B. 
Published: July 2016

ABSTRACTMacroscopic tensile tests on neat PA6 and CF/PA6 prepregs showed that the cooling rate significantly affects the mechanical properties of CF/PA6 composites because of their different crystallization behaviors both at the fiber surface and in the matrix. Polarizing optical microscopy, static nanoindentation (SNI), and dynamic mechanical imaging (DMI) tests were used to characterize the anisotropic morphologies and nanomechanical performances of the interfacial characteristic regions in CF/PA6 composites at five different cooling rates. As a result, the seven interfacial characteristic regions inside the CF/PA6 composites were clearly distinguished. The interphase thickness of the CF/PA6 composites decreased with a decrease in the cooling rate. On the contrary, the interphase modulus and transcrystallinity thickness and modulus showed significant increases with a decrease in the cooling rate. The DMI and SNI test results were in agreement with each other and with the macromechanical test results. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44106.
The effect of ceria nanoparticles on improving heat resistant properties of fluorosilicone rubber
Authors: Xu Xiang , Liu Junjie , Chen Pei , Wei Dafu , Guan Yong , Lu Xiaojuan , Xiao Huining 
Published: July 2016

ABSTRACTThe thermal aging behavior of poly(3,3,3‐trifluoropropyl)methylsiloxane was investigated by thermal gravimetric analysis and isothermal aging tests, and the results indicated the degradation mechanism II, oxidation scission of the side groups, played a more important role when the temperature was below 350 °C. The addition of ceria had significantly improved the thermal stability of fluorosilicone rubber (FSR) by inhibiting the oxidation scission. Moreover, two types of ceria including laminar‐structure ceria (LS‐CeO2) and nanoparticle ceria (N‐CeO2) were prepared and surface was modified by KH570 and characterized by scanning electron microscopy, transmission electron microscope, and X‐ray diffractometer. FSR incorporated with modified LS‐CeO2 and N‐CeO2 revealed a significant improvement on the heat resistant properties. In particular, after having been thermal oxidative aged for 70 h at 250 °C, FSR containing 2 wt % of modified N‐CeO2 maintained 72.6% of tensile strength and 63.9% of elongation at break, respectively, while FSR without ceria completely failed. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44117.
Development of tunable biodegradable polyhydroxyalkanoates microspheres for controlled delivery of tetracycline for treating periodontal disease
Authors: Panith Nootchanartch , Assavanig Apinya , Lertsiri Sittiwat , Bergkvist Magnus , Surarit Rudee , Niamsiri Nuttawee 
Published: July 2016

ABSTRACTThis article was aimed at preparation and characterization of drug delivery carriers made from biodegradable polyhydroxyalkanoates (PHAs) for slow release of tetracycline (TC) for periodontal treatment. Four PHA variants; polyhydroxybutyrate (PHB), poly(hydroxybutyrate‐co‐hydroxyvalerate) with 5, 12, and 50% hydroxyvalerate were used to formulate TC‐loaded PHA microspheres by double emulsion‐solvent evaporation method. We also compared the effect of different molecular weight (Mw) of polyvinyl alcohol (PVA) acting as surface stabilizer on particle size, drug loading, encapsulation efficiency, and drug release profile. The TC‐loaded PHA microspheres exhibited microscale and nanoscale spherical morphology under scanning electron microscopy. Among formulations, TC‐loaded PHB:low Mw PVA demonstrated the highest TC loading with slow release behavior. Our results showed that the release rate from PHA microspheres was influenced by both the type of PHA and Mw of PVA stabilizer. Lastly, TC‐loaded PHB microspheres showed efficient killing activity against periodontitis‐causing bacteria, suggesting its potential application for treating periodontal disease. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44128.
Finding time‐robust fuel‐efficient paths for a call‐taxi in a stochastic city road network
Authors: Godwin T. , Sajeev Karthik , George Albert C. 
Published: July 2016

SummaryIntra‐city commuting is being revolutionized by call‐taxi services in many developing countries such as India. A customer requests a taxi via phone, and it arrives at the right time and at the right location for the pick‐up. This mode of intra‐city travel has become one of the most reliable and convenient modes of transportation for customers traveling for business and non‐business purposes. The increased number of vehicles on city roads and raising fuel costs has prompted a new type of transportation logistics problem of finding a fuel‐efficient and quickest path for a call‐taxi through a city road network, where the travel times are stochastic. The stochastic travel time of the road network is induced by obstacles such as the traffic signals and intersections. The delay and additional fuel consumption at each of these obstacles are calculated that are later imputed to the total travel time and fuel consumption of a path. A Monte‐Carlo simulation‐based approach is proposed to identify unique fuel‐efficient paths between two locations in a city road network where each obstacle has a delay distribution. A multi‐criteria score is then assigned to each unique path based on the probability that the path is fuel efficient, the average travel time of the path and the coefficient of variation of the travel times of the path. Copyright © 2016 John Wiley & Sons, Ltd.
Interaction of glucose‐derived carbon quantum dots with silver and gold nanoparticles and its application for the fluorescence detection of 6‐thioguanine
Authors: Amjadi Mohammad , Shokri Roghayeh , Hallaj Tooba 
Published: July 2016

AbstractThe interaction of glucose‐derived carbon quantum dots (CQDs) with silver (Ag) and gold (Au) nanoparticles (NPs) was explored by fluorescence spectroscopy. Both metal NPs cause an efficient quenching of CQD fluorescence, which is likely due to the energy transfer process between CQDs as donors and metal NPs as acceptors. The Stern–Volmer plots were evaluated and corresponding quenching constants were found to be 1.9 × 1010 and 2.2 × 108 M−1 for AgNPs and AuNPs, respectively. The analytical applicability of these systems was demonstrated for turn‐on fluorescence detection of the anti‐cancer drug, 6‐thioguanine. Because the CQD–AgNP system had much higher sensitivity than the CQD–AuNP system, we used it as a selective fluorescence probe in a turn‐on assay of 6‐thioguanine. Under optimum conditions, the calibration graph was linear from 0.03 to 1.0 μM with a detection limit of 0.01 μM. The developed method was applied to the analysis of human plasma samples with satisfactory results.
A New Route to Phenols: Palladium‐Catalyzed Cyclization and Oxidation of γ,δ‐Unsaturated Ketones
Authors: Samadi Sadaf , Orellana Arturo 
Published: July 2016

AbstractWe report a new strategy for the synthesis of phenols from acyclic unsaturated ketones in one pot. The reaction proceeds by palladium‐catalyzed carbopalladation of an alkene with the enol form of the tethered ketone, generating a substituted cyclohexanone. Upon introduction of a terminal oxidant a palladium‐catalyzed oxidation ensues to give the desired phenol. This approach allows the programming of phenol substituents on the acyclic substrate and therefore circumvents the limitations inherent in traditional syntheses of phenols.
Selective and High‐Yield Synthesis of Oblate Superatom [PdAu8(PPh3)8]2+
Authors: Matsuo Shota , Takano Shinjiro , Yamazoe Seiji , Koyasu Kiichirou , Tsukuda Tatsuya 
Published: July 2016

AbstractThe front cover artwork is provided by the group of Tatsuya Tsukuda at the University of Tokyo (Japan). The image shows that the PdAu8 core of [PdAu8(PPh3)8]2+ can be viewed as an oblate supertatom with an electronic configuration of (1S)2(1P)4. Read the full text of the Article at 10.1002/celc.201600115.
Three‐Dimensional Molybdenum Disulfide Nanoflowers Decorated on Graphene Nanosheets for High‐Performance Lithium‐Ion Batteries
Authors: Xu Laiqiang , Jiao Zheng , Hu Pengfei , Wang Yong , Wang Yijia , Zhang Haijiao 
Published: July 2016

AbstractA simple hydrothermal route was designed to prepare 3D flower‐like MoS2/graphene composites (FL‐MoS2/graphene). Herein, two products, denoted C‐FL‐MoS2/graphene and N‐FL‐MoS2/graphene, were produced by facile glucose‐ and glucosamine‐mediated methods, respectively. Both composites were found to show a well‐defined morphology with a unique structure, in which the dispersed MoS2 nanoflowers are tightly anchored onto the graphene nanosheets. Moreover, the nanoflowers are constructed by a lot of wrinkled MoS2 thin nanosheets, which generates numerous open voids. In the process, glucose or glucosamine as the binder plays a similar role in regulating the growth of flower‐like MoS2 on graphene. In terms of electrochemical performance, the FL‐MoS2/graphene composite demonstrates superior lithium‐storage capabilities, including a high reversible capacity, excellent cycle stability, and good rate capability, than N‐MoS2/graphene (without the addition of any binder). Specifically, C‐FL‐MoS2/graphene shows a high reversible capacity of 980 mA h g−1 at a current of 100 mA g−1 even after 100 cycles, and a significantly improved high rate capability of 740 mA h g−1 is also retained at a current density of 1000 mA g−1. The remarkable performance of FL‐MoS2/graphene was determined to result mainly from the unique architecture comprising 3D flower‐like MoS2 particles and graphene nanosheets with superior conductivity.
Eliminated Phototoxicity of TiO2 Particles by an Atomic‐Layer‐Deposited Al2O3 Coating Layer for UV‐Protection Applications
Authors: Jang Eunyong , Sridharan Kishore , Park Young Min , Park Tae Joo 
Published: July 2016

AbstractWe demonstrate the conformal coating of an ultrathin Al2O3 layer on TiO2 nanoparticles through atomic layer deposition by using a specifically designed rotary reactor to eliminate the phototoxicity of the particles for cosmetic use. The ALD reactor is modified to improve the coating efficiency as well as the agitation of the particles for conformal coating. Elemental and microstructural analyses show that ultrathin Al2O3 layers are conformally deposited on the TiO2 nanoparticles with a controlled thickness. Rhodamine B dye molecules on Al2O3‐coated TiO2 exhibited a long life time under UV irradiation, that is, more than 2 h, compared to that on bare TiO2, that is, 8 min, indicating mitigation of photocatalytic activity by the coated layer. The effect of carbon impurities in the film resulting from various deposition temperatures and thicknesses of the Al2O3 layer on the photocatalytic activity are also thoroughly investigated with controlled experimental condition by using dye molecules on the surface. Our results reveal that an increased carbon impurity resulting from a low processing temperature provides a charge conduction path and generates reactive oxygen species causing the degradation of dye molecule. A thin coated layer, that is, less than 3 nm, also induced the tunneling of electrons and holes to the surface, hence oxidizing dye molecules. Furthermore, the introduction of an Al2O3 layer on TiO2 improves the light trapping thus, enhances the UV absorption.