bluuebunny/crossref_metadata_2025_split huggingface dataset:
DNA‐Catalyzed Introduction of Azide at Tyrosine for Peptide Modification
Authors: Wang Puzhou , Silverman Scott K. 
Published: July 2016

AbstractWe show that DNA enzymes (deoxyribozymes) can introduce azide functional groups at tyrosine residues in peptide substrates. Using in vitro selection, we identified deoxyribozymes that transfer the 2′‐azido‐2′‐deoxyadenosine 5′‐monophosphoryl group (2′‐Az‐dAMP) from the analogous 5′‐triphosphate (2′‐Az‐dATP) onto the tyrosine hydroxyl group of a peptide, which is either tethered to a DNA anchor or free. Some of the new deoxyribozymes are general with regard to the amino acid residues surrounding the tyrosine, while other DNA enzymes are sequence‐selective. We use one of the new deoxyribozymes to modify free peptide substrates by attaching PEG moieties and fluorescent labels.
Rhenium(I)‐Catalyzed Generation of α,β‐Unsaturated Carbene Complex Intermediates from Propargyl Ethers for the Preparation of Cycloheptadiene Derivatives
Authors: Sogo Hideyuki , Iwasawa Nobuharu 
Published: July 2016

AbstractThe rhenium(I)‐catalyzed generation of α,β‐unsaturated carbene complex intermediates from easily available propargyl ethers was achieved for the concise construction of cycloheptadiene derivatives through the formal [4+3] cycloaddition reaction with siloxydienes.
An Iron‐Catalyzed Bond‐Making/Bond‐Breaking Cascade Merges Cycloisomerization and Cross‐Coupling Chemistry
Authors: Echeverria Pierre‐Georges , Fürstner Alois 
Published: July 2016

AbstractTreatment of readily available enynes with alkyl‐Grignard reagents in the presence of catalytic amounts of Fe(acac)3 engenders a remarkably facile and efficient reaction cascade that results in the net formation of two new C−C bonds while a C−Z bond in the substrate backbone is broken. Not only does this new manifold lend itself to the extrusion of heteroelements (Z=O, NR), but it can even be used for the cleavage of activated C−C bonds. The reaction likely proceeds via metallacyclic intermediates, the iron center of which gains ate character before reductive elimination occurs. The overall transformation represents a previously unknown merger of cycloisomerization and cross‐coupling chemistry. It provides ready access to highly functionalized 1,3‐dienes comprising a stereodefined tetrasubstituted alkene unit, which are difficult to make by conventional means.
The Strong Influence of Structure Polymorphism on the Conductivity of Peptide Fibrils
Authors: Ivnitski Denis , Amit Moran , Silberbush Ohad , Atsmon‐Raz Yoav , Nanda Jayanta , Cohen‐Luria Rivka , Miller Yifat , Ashkenasy Gonen , Ashkenasy Nurit 
Published: July 2016

AbstractPeptide fibril nanostructures have been advocated as components of future biotechnology and nanotechnology devices. However, the ability to exploit the fibril functionality for applications, such as catalysis or electron transfer, depends on the formation of well‐defined architectures. Fibrils made of peptides substituted with aromatic groups are described presenting efficient electron delocalization. Peptide self‐assembly under various conditions produced polymorphic fibril products presenting distinctly different conductivities. This process is driven by a collective set of hydrogen bonding, electrostatic, and π‐stacking interactions, and as a result it can be directed towards formation of a distinct polymorph by using the medium to enhance specific interactions rather than the others. This method facilitates the detailed characterization of different polymorphs, and allows specific conditions to be established that lead to the polymorph with the highest conductivity.
Catechols as Sources of Hydrogen Atoms in Radical Deiodination and Related Reactions
Authors: Povie Guillaume , Ford Leigh , Pozzi Davide , Soulard Valentin , Villa Giorgio , Renaud Philippe 
Published: July 2016

AbstractWhen used with trialkylboranes, catechol derivatives, which are low‐cost and low toxicity, are valuable hydrogen atom donors for radical chain reactions involving alkyl iodides and related radical precursors. The system 4‐tert‐butylcatechol/triethylborane has been used to reduce a series of secondary and tertiary iodides, a xanthate, and a thiohydroxamate ester. Catechol derivatives are right in the optimal kinetic window for synthetic applications, as demonstrated by highly efficient radical cyclizations. Cyclizations leading to the formation of quaternary centers can be performed in an all‐at‐once process (no slow addition of the hydrogen atom donor) at standard concentrations. The H‐donor properties of catechol derivatives can be fine‐tuned by changing their substitution pattern. In slow radical cyclization processes, an enhanced ratio of cyclized/uncyclized products was obtained by using 3‐methoxycatechol instead of 4‐tert‐butylcatechol.
Access to Pyrazolidin‐3,5‐diones through Anodic N–N Bond Formation
Authors: Gieshoff Tile , Schollmeyer Dieter , Waldvogel Siegfried R. 
Published: July 2016

AbstractPyrazolidin‐3,5‐diones are important motifs in heterocyclic chemistry and are of high interest for pharmaceutical applications. In classic organic synthesis, the hydrazinic moiety is installed through condensation using the corresponding hydrazine building blocks. However, most N,N′‐diaryl hydrazines are toxic and require upstream preparation owing to their low commercial availability. We present an alternative and sustainable synthetic approach to pyrazolidin‐3,5‐diones that employs readily accessible dianilides as precursors, which are anodically converted to furnish the N−N bond. The electroconversion is conducted in a simple undivided cell under constant‐current conditions.
Epoxy modification with poly(vinyl acetate) and poly(vinyl butyral). I. Structure, thermal, and mechanical characteristics
Authors: Brantseva T. V. , Solodilov V. I. , Antonov S. V. , Gorbunova I. Y. , Korohin R. A. , Shapagin A. V. , Smirnova N. M. 
Published: July 2016

ABSTRACTEfficiency of the application of high strength heat resistant thermoplastics for improving fracture toughness and impact properties of epoxy resins motivated authors to try large‐scale production thermoplastics for the same purpose. Epoxy/anhydride systems were modified by up to 8 wt % poly(vinyl acetate) (PVAc) and up to 6 wt % poly(vinyl butyral) (PVB). In epoxy–PVAc blends it was possible to obtain morphologies with continuous thermoplastic phase. However, only sea‐island morphologies with a very small size of PVB‐rich phase were observed in epoxy–PVB matrices. The former type of morphology allowed a notable 2.4‐fold increase in the fracture toughness of epoxy resin and simultaneous up to 30% decrease in its' impact strength. The latter type of morphology caused a notably lower (45%) enhancement of the epoxy fracture toughness combined with a 50% increase in its' impact strength. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44081.
Preparation of polypropylene/octadecane composite films and their use in the packaging of cherry tomatoes
Authors: Kim Dowan , Lim Mijin , Seo Jongchul 
Published: July 2016

ABSTRACTPolypropylene (PP)/octadecane (OD) composite films were prepared via twin‐screw extrusion, and their chemical, morphological, thermal, and surface properties and oxygen and water vapor permeabilities were analyzed as functions of the OD content and temperature. OD was dispersed well in the PP matrix, and two phases (i.e., the PP and OD portions) were present in the PP/OD composite films. When the temperature was increased from 10 to 30 °C, both the oxygen transmittance rate and the water vapor transmittance rate of the PP/OD composite films increased sharply because of the influence of the OD content. These results were related to the temperature‐dependent changes in the morphological structure, such as changes in the the tortuous paths and crystallinity in the composite films because of the addition of OD. In the storage test, the PP/OD (83:17) composite films continuously controlled the gas concentration of the headspace and protected against environmental factors; this reduced the enzymatic activity and led to higher quality cherry tomatoes compared to the case when the pure PP and MP33000 films were used. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44087.
Highly Efficient Photocatalysts and Continuous‐Flow Photocatalytic Reactors for Degradation of Organic Pollutants in Wastewater
Authors: Chang Sujie , Yang Xiaoqiu , Sang Yuanhua , Liu Hong 
Published: July 2016

AbstractOne of the most important applications for photocatalysis is engineered water treatment that photodegrades organic pollutants in wastewater at low cost. To overcome the low efficiency of batch degradation methods, continuous‐flow photocatalytic reactors have been proposed and have become the most promising method for mass water treatment. However, most commercial semiconductor photocatalysts are granular nanoparticles with low activity and a narrow active light wavelength band; this creates difficulties for direct use in continuous‐flow photocatalytic reactors. Therefore, a high‐performance photodegradation photocatalyst with proper morphology or structure is key for continuous photocatalytic degradation. Moreover, a well‐designed photocatalytic device is another important component for continuous‐flow photocatalysis and determines the efficiency of photocatalysis in practical water treatment. This review describes the basic design principles and synthesis of photocatalysts with excellent performance and special morphologies suitable for a filtering photocatalysis process. Certain promising continuous photodegradation reactors are also categorized and summarized. Additionally, selected scientific and technical problems that must be urgently solved are suggested.
Benzoic‐Imine‐Based Physiological‐pH‐Responsive Materials for Biomedical Applications
Authors: Qu Xiaozhong , Yang Zhenzhong 
Published: July 2016

AbstractThe benzoic imine is a dynamic covalent bond, which is stable around neutral pH value (ca. 7.4), but starts to hydrolyze at the extracellular pH value of solid tumors (ca. 6.5) and rapidly disintegrates at endosome and lysosome pH values (ca. 4.5–6.5). This characteristic is promising for the construction of physiological‐pH‐responsive materials, such as polymeric micelles, nanoparticles, and hydrogels for pharmaceutical and tissue‐engineering applications. This Focus Review summarizes recent progress in the design and synthesis of pH‐sensitive materials that contain the benzoic imine bond with biomedical objectives.
Highly Efficient, Reproducible, Uniform (CH3NH3)PbI3 Layer by Processing Additive Dripping for Solution‐Processed Planar Heterojunction Perovskite Solar Cells
Authors: Kim Hansol , Jeong Hanbin , Lee Jae Kwan 
Published: July 2016

AbstractA processing additive dripping (PAD) approach to forming highly efficient (CH3NH3)PbI3 (MAPbI3) perovskite layers was investigated. A MAPbI3(CB/DIO) perovskite film fabricated by this approach, which included briefly dripping chlorobenzene incorporating a small amount of diiodooctane (DIO) during casting of a MAPbI3 perovskite precursor dissolved in dimethylformamide, exhibited superior smooth, uniform morphologies with high crystallinity and large grains and revealed completely homogeneous surface coverage. The surface coverage and morphology of the substrate significantly affected the photovoltaic performance of planar heterojunction (PHJ) perovskite solar cells (PrSCs), resulting in a power conversion efficiency of 11.45 % with high open‐circuit voltage of 0.91 V and the highest fill factor of 80.87 %. Moreover, the PAD approach could effectively provide efficient MAPbI3(CB/DIO) perovskite layers for highly efficient, reproducible, uniform PHJ PrSC devices without performance loss or variation even over larger active areas.
Rhodium(III)‐Catalyzed Tandem [2+2+2] Annulation–Lactamization of Anilides with Two Alkynoates via Cleavage of Two Adjacent C−H or C−H/C−O bonds
Authors: Fukui Miho , Shibata Yu , Hoshino Yuki , Sugiyama Haruki , Teraoka Kota , Uekusa Hidehiro , Noguchi Keiichi , Tanaka Ken 
Published: July 2016

AbstractAn electron‐deficient CpE rhodium(III) complex bearing a cyclopentadienyl ligand with two ethyl ester substituents catalyzes the tandem [2+2+2] annulation–lactamization of acetanilides with two alkynoates via cleavage of adjacent two C−H bonds to give densely substituted benzo[cd]indolones. The reactions of meta‐methoxy‐substituted acetanilides with two alkynoates also provided benzo[cd]indolones via cleavage of adjacent C−H/C−O bonds. Furthermore, 3,5‐dimethoxyacetanilides reacted with two alkynoates to give dearomatized spiro compounds.
Bioresorbable vascular scaffold use for coronary bifurcation lesions: A substudy from GHOST EU registry
Authors: Naganuma Toru , Colombo Antonio , Lesiak Maciej , Capodanno Davide , Gori Tommaso , Nef Holger , Caramanno Giuseppe , Naber Christoph , Di Mario Carlo , Ruparelia Neil , Capranzano Piera , Wiebe Jens , Araszkiewicz Aleksander , Geraci Salvatore , Kawamoto Hiroyoshi , Pyxaras Stelios , Mattesini Alessio , Münzel Thomas , Tamburino Corrado , Latib Azeem 
Published: July 2016

ObjectivesThe aim of this study was to evaluate midterm outcomes of bioresorbable vascular scaffolds (BVS) implanted in bifurcation lesions.BackgroundBVS have emerged as an alternative to conventional metallic drug‐eluting stents for the treatment of coronary complex lesions.MethodsBetween November 2011 and January 2014, 1189 patients underwent percutaneous coronary intervention with BVS at 10 European centers (GHOST EU registry). Of these, 289 consecutive patients (302 bifurcation lesions) treated with either single‐stenting (n = 260) or double‐stenting (n = 42) were evaluated.ResultsTrue bifurcations were treated in 44.7%. Intravascular ultrasound and optical coherence tomography were utilized only in 22.2% and 21.2%, respectively. Predilation was performed in 95.4%, while postdilation of the main branch was performed in 61.3%. Final kissing inflation with no or minimal protrusion of a side‐branch balloon into main branch was performed in 18.9%. Median follow‐up period was 356 (IQR 191–419) days. The Kaplan–Meier estimated rates of target lesion failure and scaffold thrombosis (ST) were 6.4% and 2.5% at 360 days, respectively. Independent predictors for TLF were ACS and diabetes mellitus (HR 4.67; 95% CI: 1.78–12.3; P = 0.002 and HR 3.37; 95% CI: 1.38–8.26; P = 0.008, respectively).ConclusionsBVS use for coronary bifurcation lesions in an “all‐comer” population was associated with acceptable TLF rates up to midterm follow‐up. However, ST rates were higher than seen with contemporary metallic stents possibly due to the low incidence of intravascular guidance and postdilation resulting in a higher likelihood of scaffold underexpansion and malapposition, further supporting the importance of meticulous implantation technique. © 2016 Wiley Periodicals, Inc.
Tetrachloromethane as an Effective Agent to Transform Nanoparticles of Palladium and Gold in Supported Catalysts
Authors: Bonarowska Magdalena , Kaszkur Zbigniew , Słowik Grzegorz , Ryczkowski Janusz , Karpiński Zbigniew 
Published: July 2016

AbstractThe use of CCl4 as an effective medium to generate important phase changes in supported Pd and Au catalysts is presented. The dissolution of carbon that originates from CCl4 to form a PdC0.13 solid solution is more complete for the lowest temperature of the CCl4+H2 reaction (30–50 °C). At higher temperatures, the bulk carbiding competes with the hydrogenative removal of bare carbon species to contribute to an enhanced CH4 and C2H6 formation.
Alternate to Molybdenum Disulfide: A 2D, Few‐Layer Transition‐Metal Thiophosphate and Its Hydrogen Evolution Reaction Activity over a Wide pH Range
Authors: Jenjeti Ramesh Naidu , Austeria Muthu P. , Sampath Srinivasan 
Published: July 2016

AbstractA two‐dimensional, few‐layer nickel thiophosphate, NiPS3, was introduced as a hydrogen evolution reaction catalyst from aqueous acidic, alkaline, and neutral solutions. NiPS3 is semiconducting in nature, and its band structure calculations revealed the importance of the [P2S6]4− units in the adsorption of hydrogen and subsequent evolution. Onset potentials of −0.062, −0.065, and −0.298 V versus RHE were observed in acidic, alkaline, and neutral media. Tafel slopes of 55, 48, and 94 mV dec−1 and exchange current densities of 1.8×10−4, 6.1×10−4, and 3.2×10−5 A cm−2 were observed in aqueous 0.5 m H2SO4, 1 m KOH, and 3.5 % NaCl solutions, respectively. The catalyst was found to be very stable, and the constituting elements are earth abundant. The present study opens up a new class of semiconducting layered materials to catalyze various redox reactions. Achieving a single layer will be of great interest to electrical and magnetic devices.
Hydrogen‐Bond and Supramolecular‐Contact Mediated Fluorescence Enhancement of Electrochromic Azomethines
Authors: Wałęsa‐Chorab Monika , Tremblay Marie‐Hélène , Skene William G. 
Published: July 2016

AbstractAn electronic push–pull fluorophore consisting of an intrinsically fluorescent central fluorene capped with two diaminophenyl groups was prepared. An aminothiophene was conjugated to the two flanking diphenylamines through a fluorescent quenching azomethine bond. X‐ray crystallographic analysis confirmed that the fluorophore formed multiple intermolecular supramolecular bonds. It formed two hydrogen bonds involving a terminal amine, resulting in an antiparallel supramolecular dimer. Hydrogen bonding was also confirmed by FTIR and NMR spectroscopic analyses, and further validated theoretically by DFT calculations. Intrinsic fluorescence quenching modes could be reduced by intermolecular supramolecular contacts. These contacts could be engaged at high concentrations and in thin films, resulting in fluorescence enhancement. The fluorescence of the fluorophore could also be restored to an intensity similar to its azomethine‐free counterpart with the addition of water in >50 % v/v in tetrahydrofuran (THF), dimethyl sulfoxide (DMSO), and acetonitrile. The fluorophore also exhibited reversible oxidation and its color could be switched between yellow and blue when oxidized. Reversible electrochemically mediated fluorescence turn‐off on turn‐on was also possible.
Metal Oxide Assisted Preparation of Core–Shell Beads with Dense Metal–Organic Framework Coatings for the Enhanced Extraction of Organic Pollutants
Authors: del Rio Mateo , Palomino Cabello Carlos , Gonzalez Veronica , Maya Fernando , Parra Jose B. , Cerdà Victor , Turnes Palomino Gemma 
Published: July 2016

AbstractDense and homogeneous metal–organic framework (MOF) coatings on functional bead surfaces are easily prepared by using intermediate sacrificial metal oxide coatings containing the metal precursor of the MOF. Polystyrene (PS) beads are coated with a ZnO layer to give ZnO@PS core–shell beads. The ZnO@PS beads are reactive in the presence of 2‐methylimidazole to transform part of the ZnO coating into a porous zeolitic imidazolate framework‐8 (ZIF‐8) external shell positioned above the internal ZnO precursor shell. The obtained ZIF‐8@ZnO@PS beads can be easily packed in column format for flow‐through applications, such as the solid‐phase extraction of trace priority‐listed environmental pollutants. The prepared material shows an excellent permeance to flow when packed as a column to give high enrichment factors, facile regeneration, and excellent reusability for the extraction of the pollutant bisphenol A. It also shows an outstanding performance for the simultaneous enrichment of mixtures of endocrine disrupting chemicals (bisphenol A, 4‐tert‐octylphenol and 4‐n‐nonylphenol), facilitating their analysis when present at very low levels (<1 μg L−1) in drinking waters. For the extraction of the pollutant bisphenol A, the prepared ZIF‐8@ZnO@PS beads also show a superior extraction and preconcentration capacity to that of the PS beads used as precursors and the composite materials obtained by the direct growth of ZIF‐8 on the surface of the PS beads in the absence of metal oxide intermediate coatings.
The Catalytic Mechanism of the Marine‐Derived Macrocyclase PatGmac
Authors: Brás Natércia F. , Ferreira Pedro , Calixto Ana R. , Jaspars Marcel , Houssen Wael , Naismith James H. , Fernandes Pedro A. , Ramos Maria J. 
Published: July 2016

AbstractCyclic peptides are a class of compounds with high therapeutic potential, possessing bioactivities including antitumor and antiviral (including anti‐HIV). Despite their desirability, efficient design and production of these compounds has not been achieved to date. The catalytic mechanism of patellamide macrocyclization by the PatG macrocyclase domain has been computationally investigated by using quantum mechanics/molecular mechanics methodology, specifically ONIOM(M06/6‐311++G(2d,2p):ff94//B3LYP/6‐31G(d):ff94). The mechanism proposed herein begins with a proton transfer from Ser783 to His 618 and from the latter to Asp548. Nucleophilic attack of Ser783 on the substrate leads to the formation of an acyl–enzyme covalent complex. The leaving group Ala‐Tyr‐Asp‐Gly (AYDG) of the substrate is protonated by the substrate's N terminus, leading to the breakage of the P1−P1′ bond. Finally, the substrate's N terminus attacks the P1 residue, decomposing the acyl–enzyme complex forming the macrocycle. The formation and decomposition of the acyl–enzyme complex have the highest activation free energies (21.1 kcal mol−1 and 19.8 kcal mol−1 respectively), typical of serine proteases. Understanding the mechanism behind the macrocyclization of patellamides will be important to the application of the enzymes in the pharmaceutical and biotechnological industries.
NOUF6 Revisited: A Comprehensive Study of a Hexafluoridouranate(V) Salt
Authors: Scheibe Benjamin , Lippert Sina , Rudel Stefan S. , Buchner Magnus R. , Burghaus Olaf , Pietzonka Clemens , Koch Martin , Karttunen Antti J. , Kraus Florian 
Published: July 2016

AbstractWe have synthesized NOUF6 by direct reaction of NO with UF6 in anhydrous HF (aHF). Based on the unit cell volume and powder diffraction data, the compound was previously reported to be isotypic to O2PtF6, however, detailed structural data, such as the atom positions and all information that can be derived from those, were unavailable. We have therefore investigated the compound by using single‐crystal and powder X‐ray diffraction, IR, Raman, NMR, EPR, and photoluminescence spectroscopy, magnetic measurements, as well as chemical analysis, density determination, and quantum chemical calculations.
One‐Step Production of 1,3‐Butadiene from 2,3‐Butanediol Dehydration
Authors: Liu Xi , Fabos Viktoria , Taylor Stuart , Knight David W. , Whiston Keith , Hutchings Graham J. 
Published: July 2016

AbstractWe report the direct production of 1,3‐butadiene from the dehydration of 2,3‐butandiol by using alumina as catalyst. Under optimized kinetic reaction conditions, the production of methyl ethyl ketone and isobutyraldehyde, formed via the pinacol–pinacolone rearrangement, was markedly reduced and almost 80 % selectivity to 1,3‐butadiene and 1,3‐butadiene could be achieved. The presence of water plays a critical role in the inhibition of oligomerization. The amphoteric nature of γ‐Al2O3 was identified as important and this contributed to the improved catalytic selectivity when compared with other acidic catalysts.
A Short Synthesis of Aphanamol I in Both Racemic and Enantiopure Forms
Authors: Ferrara Steven J. , Burton Jonathan W. 
Published: July 2016

AbstractA short synthesis of the biologically active sesquiterpene natural product (+)‐aphanamol I in both racemic and enantiopure forms is reported. Key steps include: a catalytic enantioselective conjugate addition, an oxidative radical cyclization, and a ring‐expanding Claisen rearrangement.
ChemInform Abstract: Facile Microwave‐Assisted Synthesis of 1,3,5‐Trisubstituted Pyrazoline Derivatives Incorporating Sulfonyl Moiety.
Authors: Liu Fei , Yang Jin‐Feng , Liu Hong , Wei Wen‐Zhen , Ma Yan‐Mei 
Published: July 2016

AbstractThe microwave‐assisted cyclization of chalcones, obtained by condensation of aromatic aldehydes with acetophenones furnishes trisubstituted pyrazoline derivatives.