bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrophoretic Approaches for LogPDetermination of Small Molecules and Polymers
Authors: Leclercq Laurent , Jin Xiaoyun , Cottet Hervé 
Published: June 2016

AbstractHydrophobicity is generally related to the determination of logPvalue, which is a key parameter in the structure/activity relationship, especially in pharmaceutical and biomedical fields. The aim of this article is to focus on the capillary electrophoresis (CE)‐related techniques for the logP(or logDfor ionizable compounds) determination of small molecules and polymers. These techniques include micellar electrokinetic chromatography (MEKC), microemulsion electrokinetic chromatography (MEEKC), liposome electrokinetic chromatography (LEKC), and vesicle electrokinetic chromatography (VEKC). Comparison is made based on several parameters, such as surfactants chemical nature or composition and pH of the analysis buffer. Characterization of polymer hydrophobicity is a challenging issue because polymeric analytes (and especially polyelectrolytes) tend very often to remain at the water/organic phase interface making the classical shake‐flask method difficult to apply. In addition, polymers present distributions of composition and molar masses generating hydrophobicity distribution that should be characterized beyond the determination of average logP(or logD) values. Recently, determination of polymer logDdistribution has been addressed and was reviewed in detail in the case of polycationic gene delivery vectors.
Oxidative Coupling of Enamines and Disulfides via Tetrabutylammonium Iodide/tert‐Butyl Hydroperoxide‐Mediated Intermolecular Oxidative C(sp2)S Bond Formation Under Transition Metal‐Free Conditions
Authors: Sun Jiyun , Zhang‐Negrerie Daisy , Du Yunfei 
Published: June 2016

AbstractThe reaction of enamine compounds with disulfides in the presence of tert‐butyl hydroperoxide and a catalytic amount of tetrabutylammonium iodide conveniently afforded a variety of α‐thioenamine compounds through the intermolecular oxidative C(sp2)S coupling. Incorporating both of the sulfide moieties in the disulfides into the final products under oxidative conditions, this novel approach exhibits the feature of atom efficiency. A radical mechanistic pathway for the reaction process has been proposed.magnified image
Palladium‐Catalyzed α‐Arylation of Methyl Sulfonamides with Aryl Chlorides
Authors: Zheng Bing , Li Minyan , Gao Gui , He Yuying , Walsh Patrick J. 
Published: June 2016

AbstractA palladium‐catalyzed α‐arylation of sulfonamides with aryl chlorides is presented. A Buchwald‐type pre‐catalyst formed with Kwong’s indole‐based ligand enabled this transformation to be compatible with a large variety of methyl sulfonamides and aryl chlorides in good to excellent yields. Importantly, under the optimized reaction conditions, only mono‐arylated products were observed. This method has been applied to the efficient synthesis of sumatriptan, which is used to treat migraines.magnified image
Copper‐Catalyzed Addition of Alkylboranes to Iminoacetates: Access to α‐Alkyl Branched α‐Amino Acids
Authors: Xiao Xinsheng , Zhang Wei , Lu Xiaoxia , Deng Yuanfu , Jiang Huangfeng , Zeng Wei 
Published: June 2016

AbstractA copper(I)‐catalyzed addition of alkylborane reagents to α‐iminoacetates has been developed to assemble both acyclic and cyclic α‐branched α‐amino carboxylic acid derivatives in good yields. A wide variety of unactivated alkenes are well tolerated in this transformation.magnified image
Palladium‐Catalyzed Oxidative Carbonylation of Aromatic C−H Bonds with Alcohols using Molybdenum Hexacarbonyl as the Carbon Monoxide Source
Authors: Wang Zechao , Li Yahui , Zhu Fengxiang , Wu Xiao‐Feng 
Published: June 2016

AbstractWith molybdenum hexacarbonyl as the carbon monoxide source, a general palladium‐catalyzed carbonylative transformation of the C−H bond on aromatic rings to produce esters has been developed. Good yields of the corresponding products have been obtained with wide functional group tolerance and excellent regioselectivity. A variety of aliphatic alcohols are suitable reactants here.magnified image
Tandem Prins Cyclization for the Stereoselective Synthesis of Bridged Benzopyran Derivatives
Authors: Subba Reddy Basi V. , Srivastava Nikhil , Begum Zubeda , Lakshmi Jerripothula K. , Sridhar Balasubramanian 
Published: June 2016

AbstractA tandem bicyclization strategy has been developed for the stereoselective synthesis of 3,4‐dihydro‐2 H,6H‐2,6‐methanobenzo[b][1,5]dioxocine derivatives in good yields and selectivities through the cyclocondensation of 2‐(1‐hydroxy‐3‐methylbut‐3‐en‐1‐yl)phenol with various aldehydes by using 10 mol % BF3⋅OEt2. This is the first reported stereoselective construction of a bridged tricyclic skeleton through a cascade Prins cyclization procedure. This process constitutes an elegant strategy for the quick construction of tricyclic architectures in a single step.
Rh(II)‐Catalyzed Chemoselective Synthesis of 3‐Substituted Oxindoles by C(sp2)−H and C(sp2)−N Functionalization of β‐Enaminoesters
Authors: Yun Sang Hyeon , Xia Likai , Kim Sung Hong , Lee Yong Rok 
Published: June 2016

AbstractA novel chemoselective synthesis of 3‐substituted oxindoles and 3‐substituted 3‐aminooxindoles starting from various 3‐diazoindolin‐2‐ones and β‐enaminoesters was developed through rhodium(II)‐catalyzed C(sp2)−H and C(sp2)−N functionalization. This protocol provides a rapid synthetic route to a diverse range of 3‐substituted oxindoles and 3‐substituted 3‐aminooxindoles with good yields. The chemoselectivity for the formation of the 3‐substituted oxindoles and 3‐substituted 3‐aminooxindoles was controlled by the substituents on the nitrogen atom of the β‐enaminoesters.
Die Steuerung des Stealth‐Effekts von Nanoträgern durch das Verständnis der Proteinkorona
Authors: Schöttler Susanne , Landfester Katharina , Mailänder Volker 
Published: June 2016

AbstractIn den letzten zehn Jahren haben polymere Nanoträger immer mehr Interesse und Verwendung in medizinischen Anwendungen gefunden. Besonders beim Einsatz als Wirkstoff‐Träger lassen sich mit Nanoträgern viele Hindernisse der medikamentösen Therapie überwinden. Ihre Anwendung wird jedoch durch die komplexe Zusammensetzung der Partikelabdeckung mit Blutproteinen (“Proteinkorona”) erschwert. Diese Proteinkorona macht Vorhersagen über die zelluläre Interaktion, Biodistribution und Toxizität nahezu unmöglich. Vor allem die unspezifische Aufnahme der Nanoträger ist ein wesentliches Hindernis bei der klinischen Anwendung. Dieser Kurzaufsatz gibt einen Überblick über unseren Kenntnisstand auf diesem Gebiet; der Fokus liegt dabei auf Oberflächenfunktionalisierungen, die die unspezifische Aufnahme reduzieren (“Stealth‐Effekt”). Erörtert werden auch Möglichkeiten zur weiteren Verbesserung von Nanoträgern.
Computer‐Aided Production of Scaffolded DNA Nanostructures from Flat Sheet Meshes
Authors: Benson Erik , Mohammed Abdulmelik , Bosco Alessandro , Teixeira Ana I. , Orponen Pekka , Högberg Björn 
Published: June 2016

AbstractThe use of DNA as a nanoscale construction material has been a rapidly developing field since the 1980s, in particular since the introduction of scaffolded DNA origami in 2006. Although software is available for DNA origami design, the user is generally limited to architectures where finding the scaffold path through the object is trivial. Herein, we demonstrate the automated conversion of arbitrary two‐dimensional sheets in the form of digital meshes into scaffolded DNA nanostructures. We investigate the properties of DNA meshes based on three different internal frameworks in standard folding buffer and physiological salt buffers. We then employ the triangulated internal framework and produce four 2D structures with complex outlines and internal features. We demonstrate that this highly automated technique is capable of producing complex DNA nanostructures that fold with high yield to their programmed configurations, covering around 70 % more surface area than classic origami flat sheets.
Integrin‐Targeting Knottin Peptide–Drug Conjugates Are Potent Inhibitors of Tumor Cell Proliferation
Authors: Cox Nick , Kintzing James R. , Smith Mark , Grant Gerald A. , Cochran Jennifer R. 
Published: June 2016

AbstractAntibody–drug conjugates (ADCs) offer increased efficacy and reduced toxicity compared to systemic chemotherapy. Less attention has been paid to peptide–drug delivery, which has the potential for increased tumor penetration and facile synthesis. We report a knottin peptide–drug conjugate (KDC) and demonstrate that it can selectively deliver gemcitabine to malignant cells expressing tumor‐associated integrins. This KDC binds to tumor cells with low‐nanomolar affinity, is internalized by an integrin‐mediated process, releases its payload intracellularly, and is a highly potent inhibitor of brain, breast, ovarian, and pancreatic cancer cell lines. Notably, these features enable this KDC to bypass a gemcitabine‐resistance mechanism found in pancreatic cancer cells. This work expands the therapeutic relevance of knottin peptides to include targeted drug delivery, and further motivates efforts to expand the drug‐conjugate toolkit to include non‐antibody protein scaffolds.
Enaminones as Synthons for a Directed C−H Functionalization: RhIII‐Catalyzed Synthesis of Naphthalenes
Authors: Zhou Shuguang , Wang Jinhu , Wang Lili , Song Chao , Chen Kehao , Zhu Jin 
Published: June 2016

AbstractThe use of enaminones as effective synthons for a directed C−H functionalization is reported. Proof‐of‐concept protocols have been developed for the RhIII‐catalyzed synthesis of naphthalenes, based on the coupling of enaminones with either alkynes or α‐diazo‐β‐ketoesters. Two inherently reactive functionalities (hydroxy and aldehyde groups) are integrated into the newly formed cyclic framework and a broad range of substituents are tolerated, rendering target products readily available for further elaboration.
A Genetically Encoded β‐Lactamase Reporter for Ultrasensitive 129Xe NMR in Mammalian Cells
Authors: Wang Yanfei , Roose Benjamin W. , Palovcak Eugene J. , Carnevale Vincenzo , Dmochowski Ivan J. 
Published: June 2016

AbstractMolecular imaging holds considerable promise for elucidating biological processes in normal physiology as well as disease states, but requires noninvasive methods for identifying analytes at sub‐micromolar concentrations. Particularly useful are genetically encoded, single‐protein reporters that harness the power of molecular biology to visualize specific molecular processes, but such reporters have been conspicuously lacking for in vivo magnetic resonance imaging (MRI). Herein, we report TEM‐1 β‐lactamase (bla) as a single‐protein reporter for hyperpolarized (HP) 129Xe NMR, with significant saturation contrast at 0.1 μm. Xenon chemical exchange saturation transfer (CEST) interactions with the primary allosteric site in bla give rise to a unique saturation peak at 255 ppm, well removed (≈60 ppm downfield) from the 129Xe‐H2O peak. Useful saturation contrast was also observed for bla expressed in bacterial cells and mammalian cells.
Isolation and Crystallographic Characterization of the Labile Isomer of Y@C82 Cocrystallized with Ni(OEP): Unprecedented Dimerization of Pristine Metallofullerenes
Authors: Bao Lipiao , Pan Changwang , Slanina Zdenek , Uhlik Filip , Akasaka Takeshi , Lu Xing 
Published: June 2016

AbstractAlthough the major isomers of M@C82 (namely M@C2v(9)‐C82, where M is a trivalent rare‐earth metal) have been intensively investigated, the lability of the minor isomers has meant that they have been little studied. Herein, the first isolation and crystallographic characterization of the minor Y@C82 isomer, unambiguously assigned as Y@Cs(6)‐C82 by cocrystallization with Ni(octaethylporphyrin), is reported. Unexpectedly, a regioselective dimerization is observed in the crystalline state of Y@Cs(6)‐C82. In sharp contrast, no dimerization occurs for the major isomer Y@C2v(9)‐C82 under the same conditions, indicating a cage‐symmetry‐induced dimerization process. Further experimental and theoretical results disclose that the regioselective dimer formation is a consequence of the localization of high spin density on a special cage‐carbon atom of Y@Cs(6)‐C82 which is caused by the steady displacement of the Y atom inside the Cs(6)‐C82 cage.
Molecular Engineering of Conjugated Polybenzothiadiazoles for Enhanced Hydrogen Production by Photosynthesis
Authors: Yang Can , Ma Beatriz Chiyin , Zhang Linzhu , Lin Sen , Ghasimi Saman , Landfester Katharina , Zhang Kai A. I. , Wang Xinchen 
Published: June 2016

AbstractThe search for metal‐free organic photocatalysts for H2 production from water using visible light remains a key challenge. Reported herein is a molecular structural design of pure organic photocatalysts, derived from conjugated polybenzothiadiazoles, for photocatalytic H2 evolution using visible light. By alternating the substitution position of the electron‐withdrawing benzothiadizole unit on the phenyl unit as a comonomer, various polymers with either one‐ or three‐dimensional structures were synthesized and the effect of the molecular structure on their catalytic activity was investigated. Photocatalytic H2 evolution efficiencies up to 116 μmol h−1 were observed by employing the linear polymer based on a phenyl‐benzothiadiazole alternating main chain, with an apparent quantum yield (AQY) of 4.01 % at 420 nm using triethanolamine as the sacrificial agent.
Influence of molecular structure and reinforcement on fatigue behavior of tough polypropylene materials
Authors: Arbeiter Florian J. , Frank Andreas , Pinter Gerald 
Published: June 2016

ABSTRACTMolecular structure and reinforcement heavily influence the crack growth resistance of polypropylene materials. Aim of this study is to investigate the fatigue behavior of different unreinforced and reinforced tough polypropylene materials used for piping applications. Due to high resistance against crack growth, these materials cannot be tested in the application relevant quasi‐brittle failure mode within feasible amounts of time. In this work, the new cyclic cracked round bar test, developed for tough polyethylene materials, has been examined as a possible method to characterize this important type of failure mode in homo‐, random‐, and reinforced polypropylene. Even though molecular mass distribution, which is often used to explain differences in crack growth resistance of polymers, was similar for unreinforced materials, fatigue lifetimes differed greatly. The mismatch of molecular mass and fatigue lifetime was mainly attributed to the different buildup and morphology of the base polymer. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43948.
Preparation and swelling behavior of moisture‐absorbing polyurethane films impregnated with superabsorbent sodium polyacrylate particles
Authors: Lee Jeong Hoon , Lee Seung Geol 
Published: June 2016

ABSTRACTMoisture‐absorbing composite films were prepared with superabsorbent sodium polyacrylate particles and solvent‐type polyurethane for applications in fabrics. To study the effect of the particle size of sodium polyacrylates on the swelling capacity and deswelling behavior of the composite films, we prepared sodium polyacrylates with different particle sizes ranging from 277 μm to 485 nm. The rate of absorption and the swelling capacity of the composite films were generally observed to increase with decreasing sodium polyacrylate particle size—except that the water absorbency of the composite film containing the very smallest, 485‐nm‐size, sodium polyacrylate particles was lower than that yielded by the larger particles, perhaps because these very small sodium polyacrylate particles were impregnated inside the polyurethane matrix rather than on the surface. Meanwhile, the deswelling behavior was not significantly affected by the particle size. Differences in the ionic solutions also significantly affected the swelling capacity of the composite film and altered its swelling kinetics. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43973.
Petrographic analyses of sand temper/inclusions in ceramics of Kikiniu, Kikori River and modern sand samples from the Gulf Province (Papua New Guinea)
Authors: MARSAGLIA KATHLEEN M. , KRAMER KIMBERLY G. , DAVID BRUNO , SKELLY ROBERT J. 
Published: June 2016

ABSTRACTThe archaeological site of Kikiniu (a.k.a. Kulupuari) in the mid‐reaches of the Kikori River, Gulf Province (Papua New Guinea) contains a rich assemblage of ceramic sherds dating to 1550–1000 calBP. This is a region for which there is no ethnographic and no prior archaeological evidence of ceramic manufacture, but for which during the ethnographic period premade pottery vessels are well known to have been imported en masse from long‐distance seafarers from Yule Island and Port Moresby. Here we present initial petrographic analyses of sand temper/inclusions from 20 excavated sherds from Kikiniu, and 14 samples of modern beach and river sand collected across the area, to determine whether the Kikiniu ceramics could have been locally manufactured, and if not, from where they were imported. Our preliminary results confirm that the majority of the sherds, and possibly all, are from ceramics that were probably imported from manufacturing sites to the south‐east. Given that the Kikiniu region was then a rainforest, sago‐rich region, ceramics probably arrived at Kikiniu as part of the sago trade as far back as c.1550–1000 calBP.
Photoinduced Charge‐Transfer State of 4‐Carbazolyl‐3‐(trifluoromethyl)benzoic Acid: Photophysical Property and Application to Reduction of Carbon−Halogen Bonds as a Sensitizer
Authors: Matsubara Ryosuke , Shimada Toshiyuki , Kobori Yasuhiro , Yabuta Tatsushi , Osakai Toshiyuki , Hayashi Masahiko 
Published: June 2016

AbstractThe photoinduced persistent intramolecular charge‐transfer state of 4‐carbazolyl‐3‐(trifluoromethyl)benzoic acid was confirmed. It showed a higher catalytic activity in terms of yield and selectivity in the photochemical reduction of alkyl halides compared to the parent carbazole. Even unactivated primary alkyl bromides could be reduced by this photocatalyst. The high catalytic activity is rationalized by considering the slower backward single‐electron transfer owing to the spatial separation of the donor and acceptor subunits.
Copper Phthalocyanine‐Functionalized Graphitic Carbon Nitride: A Hybrid Heterostructure toward Photoelectrochemical and Photocatalytic Degradation Applications
Authors: Liu Zhong‐Guo , Wan Jia‐Yun , Yang Ze , Wang Shi‐Quan , Wang Hang‐Xing 
Published: June 2016

AbstractIn this work, alcian blue 8GX (AB), a copper(II) phthalocyanine derivative, was employed to functionalize graphitic carbon nitride (g‐C3N4) for the preparation of a highly efficient photocatalyst. The approach relies on a facile AB‐assisted ethanol/water mixed‐solvent exfoliation of bulk g‐C3N4. The as‐prepared g‐C3N4/AB hybrid possesses significantly enhanced solution dispersibility and photoelectrochemical performance resulting from the synergistic effect between g‐C3N4 and AB, which involves the optimization of intimate interfacial contact, extension of light absorption range, and enhancement of charge‐transfer efficiency. This synergy contributes enormously to the photocatalytic degradation of rhodamine 6G (R6G) under light irradiation.
Towards Highly‐Efficient Phototriggered Data Storage by Utilizing a Diketopyrrolopyrrole‐Based Photoelectronic Small Molecule
Authors: Li Yang , Li Hua , He Jinghui , Xu Qingfeng , Li Najun , Chen Dongyun , Lu Jianmei 
Published: June 2016

AbstractA cooperative photoelectrical strategy is proposed for effectively modulating the performance of a multilevel data‐storage device. By taking advantage of organic photoelectronic molecules as storage media, the fabricated device exhibited enhanced working parameters under the action of both optical and electrical inputs. In cooperation with UV light, the operating voltages of the memory device were decreased, which was beneficial for low energy consumption. Moreover, the ON/OFF current ratio was more tunable and facilitated high‐resolution multilevel storage. Compared with previous methods that focused on tuning the storage media, this study provides an easy approach for optimizing organic devices through multiple physical channels. More importantly, this method holds promise for integrating multiple functionalities into high‐density data‐storage devices.
Self‐assembly of a Linear Ni9 Triple‐helical Supramolecule with Dominant Ferromagnetic Interactions
Authors: Jin Rui , Cai Zhong‐Sheng , Dai Shuang , Jiang Xuan‐Feng , Zheng Li‐Min , Yu Shu‐Yan 
Published: June 2016

AbstractA linear triple‐helical supramolecule Ni9L6 has been prepared through a controllable self‐assembly approach using 1,3‐bis‐(3‐oxo‐3‐phenylpropionyl)‐2‐hydroxy‐5‐methylbenzene (H3L) and Ni(OAc)2 under solvothermal conditions. Single‐crystal X‐ray diffraction analysis confirms the axial C3 symmetrical helical structure of the product and the temperature‐dependent magnetic susceptibility corresponds to a typical shape of a paramagnet showing dominant ferromagnetic exchange couplings between the neighboring NiII ions.
Synthesis of an Orthogonally Protected Polyhydroxylated Cyclopentene from l‐Sorbose
Authors: Lo Re Daniele , Jones Leigh , Giralt Ernest , Murphy Paul 
Published: June 2016

AbstractThe use of l‐sorbose in the synthesis of functionalized cyclopentene derivatives was accomplished. These cyclopentene derivatives are related to those found in naturally occurring jatrophane frameworks and in other bioactive compounds. The formation of allyl α‐l‐sorbopyranoside was a key synthetic step. Regioselective introduction of protecting groups was followed by the hydrolysis of the allyl glycoside to furnish a fully protected acyclic l‐sorbose derivative. This acyclic intermediate was subsequently used to give an orthogonally protected polyhydroxylated cyclopentene, which has potential for further synthesis of bioactive compounds. The protected cyclopentene itself showed a clear cytotoxic activity when tested against a panel of human cancer cell lines (HT29, LS174T, SW620, A549, and HeLa cells).
Large‐scale purification and characterization of recombinant human stem cell factor in Escherichia coli
Authors: Chen Liang‐hua , Cai Feng , Zhang Dan‐ju , Zhang Li , Zhu Peng , Gao Shun 
Published: June 2016

AbstractThe pharmacological importance of recombinant human stem cell factor (rhSCF) has increased the demand to establish effective and large‐scale production and purification processes. A good source of bioactive recombinant protein with capability of being scaled‐up without losing activity has always been a challenge. The objectives of the study were the rapid and efficient pilot‐scale expression and purification of rhSCF. The gene encoding stem cell factor (SCF) was cloned into pBV220 and transformed into Escherichia coli. The recombinant SCF was expressed and isolated using a procedure consisting of isolation of inclusion bodies (IBs), denaturation, and refolding followed by chromatographic steps toward purification. The yield of rhSCF reached 835.6 g/20 L, and the expression levels of rhSCF were about 33.9% of the total E. coli protein content. rhSCF was purified by isolation of IBs, denaturation, and refolding, followed by SP‐Sepharose chromatography, Source 30 reversed‐phase chromatography, and Q‐Sepharose chromatography. This procedure was developed to isolate 5.5 g of rhSCF (99.5% purity) with specific activity at 0.96 × 106 IU/mg, endotoxin levels of pyrogen at 1.0 EU/mg, and bacterial DNA at 10 ng/mg. Pilot‐scale fermentations and purifications were set up for the production of rhSCF that can be upscaled for industry.