bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Self‐Assembled Spherical Complex Displaying a Gangliosidic Glycan Cluster Capable of Interacting with Amyloidogenic Proteins
Authors: Sato Sota , Yoshimasa Yutaka , Fujita Daishi , Yagi‐Utsumi Maho , Yamaguchi Takumi , Kato Koichi , Fujita Makoto 
Published: May 2015

AbstractPhysiological and pathological functions of glycans are promoted through their clustering effects as exemplified by a series of gangliosides, sialylated glycosphingolipids, which serve as acceptors for bacterial toxins and viruses. Furthermore, ganglioside GM1 clusters on neuronal cell membranes specifically interact with amyloidogenic proteins, triggering their conformational transitions and leading to neurodegeneration. Here we develop a self‐assembled spherical complex that displays a cluster of the GM1 pentasaccharide, and successfully demonstrate its ability to interact with amyloid β and α‐synuclein. Due to the lack of hydrophobic lipid moieties, which would stably trap these cohesive proteins or give rise to toxic aggregates, this artificial cluster enabled NMR spectroscopic characterization of the early encounter stage of protein interactions with its outer carbohydrate moieties, which were not observable with previous glycan clusters.
Computer‐gestütztes Design ionischer Flüssigkeiten zur CO2‐Absorption
Authors: Firaha Dzmitry S. , Hollóczki Oldamur , Kirchner Barbara 
Published: May 2015

AbstractIonische Flüssigkeiten (ILs) variieren stark in ihrer Wechselwirkung mit CO2. Es wird ein einfaches theoretisches Verfahren vorgeschlagen, mit dem sich das Absorptionsverhalten von ILs vorhersagen lässt. Während starke Wechselwirkungen der IL‐Anionen mit CO2 chemische Absorption bedeuten, weisen schwache auf physikalische Absorption hin. Eine Abschätzung mit klarer Trennung zwischen chemischer und physikalischer Absorption kann leicht erhalten werden, indem die Geometrie in Gegenwart eines Solvatationsmodells optimiert wird statt wie bisher nur in der Gasphase. Aus diesen solvatisierten Geometrien lassen sich Gibbs‐Energien erhalten, die sehr gut mit experimentellen Werten übereinstimmen. Somit können die berechneten Gibbs‐Energien mit vermessenen Kapazitäten korreliert werden. Vielversprechende Anionen für den Entwurf von ILs für reversible chemische CO2‐Absorption können durch berechnete Gibbs‐Reaktionsenergien definiert werden. Für diese Kandidaten lassen sich wiederum die Kapazitäten aus der eben erwähnten Korrelation abschätzen.
The Role of Substituent Effects in Tuning Metallophilic Interactions and Emission Energy of Bis‐4‐(2‐pyridyl)‐1,2,3‐triazolatoplatinum(II) Complexes
Authors: Prabhath M. R. Ranga , Romanova Julia , Curry Richard J. , Silva S. Ravi P. , Jarowski Peter D. 
Published: May 2015

AbstractThe photoluminescence spectra of a series of 5‐substituted pyridyl‐1,2,3‐triazolato PtII homoleptic complexes show weak emission tunability (ranging from λ=397–408 nm) in dilute (10−6 M) ethanolic solutions at the monomer level and strong tunability in concentrated solutions (10−4 M) and thin films (ranging from λ=487–625 nm) from dimeric excited states (excimers). The results of density functional calculations (PBE0) attribute this “turn‐on” sensitivity and intensity in the excimer to strong Pt–Pt metallophilic interactions and a change in the excited‐state character from singlet metal‐to‐ligand charge transfer (1MLCT) to singlet metal‐metal‐to‐ligand charge transfer (1MMLCT) emissions in agreement with lifetime measurements.
Zinc‐Catalyzed Alkyne Oxidation/CH Functionalization: Highly Site‐Selective Synthesis of Versatile Isoquinolones and β‐Carbolines
Authors: Li Long , Zhou Bo , Wang Yong‐Heng , Shu Chao , Pan Yi‐Fei , Lu Xin , Ye Long‐Wu 
Published: May 2015

AbstractAn efficient zinc(II)‐catalyzed alkyne oxidation/CH functionalization sequence was developed, thus leading to highly site‐selective synthesis of a variety of isoquinolones and β‐carbolines. Importantly, in contrast to the well‐established gold‐catalyzed intermolecular alkyne oxidation, over‐oxidation can be completely suppressed in this system and the reaction most likely proceeds by a Friedel–Crafts‐type pathway. Mechanistic studies and theoretical calculations are described.
Aufklärung der donorbasenfreien Aggregation von Lithiumdiisopropylamid in Kohlenwasserstoffen mithilfe einer DOSY‐Methode
Authors: Neufeld Roman , John Michael , Stalke Dietmar 
Published: May 2015

AbstractLithiumdiisopropylamid (LDA) ist ein überaus wichtiges Reagens und nimmt vor allem in der organischen Synthesechemie eine Schlüsselrolle bei einer Vielzahl von Deprotonierungsreaktionen ein. Trotzdem ist seine Aggregation, und damit die Gestalt der reaktiven Spezies in nichtdonierenden Lösungsmitteln, bislang noch ungeklärt. Hier lösen wir dieses Problem durch eine neu entwickelte DOSY‐NMR‐Methode. Sie beruht auf externen Kalibrierungskurven mit normalisierten Diffusionskoeffizienten und ist vielfältig einsetzbar.
Targeting the Two Oncogenic Functional Sites of the HPV E6 Oncoprotein with a High‐Affinity Bivalent Ligand
Authors: Ramirez Juan , Poirson Juline , Foltz Clémence , Chebaro Yassmine , Schrapp Maxime , Meyer Amandine , Bonetta Anaëlle , Forster Anne , Jacob Yves , Masson Murielle , Deryckère François , Travé Gilles 
Published: May 2015

AbstractThe E6 oncoproteins of high‐risk mucosal (hrm) human papillomaviruses (HPVs) contain a pocket that captures LxxLL motifs and a C‐terminal motif that recruits PDZ domains, with both functions being crucial for HPV‐induced oncogenesis. A chimeric protein was built by fusing a PDZ domain and an LxxLL motif, both known to bind E6. NMR spectroscopy, calorimetry and a mammalian protein complementation assay converged to show that the resulting PDZ‐LxxLL chimera is a bivalent nanomolar ligand of E6, while its separated PDZ and LxxLL components are only micromolar binders. The chimera binds to all of the hrm‐HPV E6 proteins tested but not to low‐risk mucosal or cutaneous HPV E6. Adenovirus‐mediated expression of the chimera specifically induces the death of HPV‐positive cells, concomitant with increased levels of the tumour suppressor P53, its transcriptional target p21, and the apoptosis marker cleaved caspase 3. The bifunctional PDZ‐LxxLL chimera opens new perspectives for the diagnosis and treatment of HPV‐induced cancers.
The Role of Oxygen in the Degradation of Methylammonium Lead Trihalide Perovskite Photoactive Layers
Authors: Aristidou Nicholas , Sanchez‐Molina Irene , Chotchuangchutchaval Thana , Brown Michael , Martinez Luis , Rath Thomas , Haque Saif A. 
Published: May 2015

AbstractIn this paper we report on the influence of light and oxygen on the stability of CH3NH3PbI3 perovskite‐based photoactive layers. When exposed to both light and dry air the mp‐Al2O3/CH3NH3PbI3 photoactive layers rapidly decompose yielding methylamine, PbI2, and I2 as products. We show that this degradation is initiated by the reaction of superoxide (O2−) with the methylammonium moiety of the perovskite absorber. Fluorescent molecular probe studies indicate that the O2− species is generated by the reaction of photoexcited electrons in the perovskite and molecular oxygen. We show that the yield of O2− generation is significantly reduced when the mp‐Al2O3 film is replaced with an mp‐TiO2 electron extraction and transport layer. The present findings suggest that replacing the methylammonium component in CH3NH3PbI3 to a species without acid protons could improve tolerance to oxygen and enhance stability.
Oxygen Evolution Catalyzed by a Mononuclear Ruthenium Complex Bearing Pendant SO3− Groups
Authors: Yoshida Masaki , Kondo Mio , Torii Sena , Sakai Ken , Masaoka Shigeyuki 
Published: May 2015

AbstractRational molecular design of catalytic systems capable of smooth OO bond formation is critical to the development of efficient catalysts for water oxidation. A new ruthenium complex was developed, which bears pendant SO3− groups in the secondary coordination sphere: [Ru(terpy)(bpyms)(OH2)] (terpy=2,2′:6′,2′′‐terpyridine, bpyms=2,2′‐bipyridine‐5,5′‐bis(methanesulfonate)). Water oxidation driven by a Ce4+ oxidant is distinctly accelerated upon introduction of the pendant SO3− groups in comparisons to the parent catalyst, [Ru(terpy)(bpy)(OH2)]2+ (bpy=2,2′‐bipyridine). Spectroscopic, electrochemical, and crystallographic investigations concluded that the pendant SO3− groups promote the formation of an OO bond via the secondary coordination sphere on the catalyst, whereas the influence of the pendant SO3− groups on the electronic structure of the [Ru(terpy)(bpy)(OH2)]2+ core is negligible. The results of this work indicate that modification of the secondary coordination sphere is a valuable strategy for the design of water oxidation catalysts.
Gallotannins and Tannic Acid: First Chemical Syntheses and In Vitro Inhibitory Activity on Alzheimer’s Amyloid β‐Peptide Aggregation
Authors: Sylla Tahiri , Pouységu Laurent , Da Costa Grégory , Deffieux Denis , Monti Jean‐Pierre , Quideau Stéphane 
Published: May 2015

AbstractThe screening of natural products in the search for new lead compounds against Alzheimer’s disease has unveiled several plant polyphenols that are capable of inhibiting the formation of toxic β‐amyloid fibrils. Gallic acid based gallotannins are among these polyphenols, but their antifibrillogenic activity has thus far been examined using “tannic acid”, a commercial mixture of gallotannins and other galloylated glucopyranoses. The first total syntheses of two true gallotannins, a hexagalloylglucopyranose and a decagalloylated compound whose structure is commonly used to depict “tannic acid”, are now described. These depsidic gallotannins and simpler galloylated glucose derivatives all inhibit amyloid β‐peptide (Aβ) aggregation in vitro, and monogalloylated α‐glucogallin and a natural β‐hexagalloylglucose are shown to be the strongest inhibitors.
Hypoxia Induced by Upconversion‐Based Photodynamic Therapy: Towards Highly Effective Synergistic Bioreductive Therapy in Tumors
Authors: Liu Yanyan , Liu Yong , Bu Wenbo , Cheng Chao , Zuo Changjing , Xiao Qingfeng , Sun Yong , Ni Dalong , Zhang Chen , Liu Jianan , Shi Jianlin 
Published: May 2015

AbstractLocal hypoxia in tumors is an undesirable consequence of photodynamic therapy (PDT), which will lead to greatly reduced effectiveness of this therapy. Bioreductive pro‐drugs that can be activated at low‐oxygen conditions will be highly cytotoxic under hypoxia in tumors. Based on this principle, double silica‐shelled upconversion nanoparticles (UCNPs) nanostructure capable of co‐delivering photosensitizer (PS) molecules and a bioreductive pro‐drug (tirapazamine, TPZ) were designed (TPZ‐UC/PS), with which a synergetic tumor therapeutic effect has been achieved first by UC‐based (UC‐) PDT under normal oxygen environment, immediately followed by the induced cytotoxicity of activated TPZ when oxygen is depleted by UC‐PDT. Treatment with TPZ‐UC/PS plus NIR laser resulted in a remarkably suppressed tumor growth as compared to UC‐PDT alone, implying that the delivered TPZ has a profound effect on treatment outcomes for the much‐enhanced cytotoxicity of TPZ under PDT‐induced hypoxia.
Inverted Fuel Cell: Room‐Temperature Hydrogen Separation from an Exhaust Gas by Using a Commercial Short‐Circuited PEM Fuel Cell without Applying any Electrical Voltage
Authors: Friebe Sebastian , Geppert Benjamin , Caro Jürgen 
Published: May 2015

AbstractA short‐circuited PEM fuel cell with a Nafion membrane has been evaluated in the room‐temperature separation of hydrogen from exhaust gas streams. The separated hydrogen can be recovered or consumed in an in situ olefin hydrogenation when the fuel cell is operated as catalytic membrane reactor. Without applying an outer electrical voltage, there is a continuous hydrogen flux from the higher to the lower hydrogen partial pressure side through the Nafion membrane. On the feed side of the Nafion membrane, hydrogen is catalytically split into protons and electrons by the Pt/C electrocatalyst. The protons diffuse through the Nafion membrane, the electrons follow the short‐circuit between the two brass current collectors. On the cathode side, protons and electrons recombine, and hydrogen is released.
Remote Hydroxylation through Radical Translocation and Polar Crossover
Authors: Hollister Kyle A. , Conner Elizabeth S. , Spell Mark L. , Deveaux Kristina , Maneval Léa , Beal Michael W. , Ragains Justin R. 
Published: May 2015

AbstractMild conditions are reported for the hydroxylation of aliphatic CH bonds through radical translocation, oxidation to carbocation, and nucleophilic trapping with H2O. This remote functionalization employs fac‐[Ir(ppy)3] together with Tzo sulfonate esters and sulfonamides to facilitate the site‐selective replacement of relatively inert CH bonds with the more synthetically useful COH group. The hydroxylation of a range of substrates and the methoxylation of two substrates through 1,6‐ and 1,7‐hydrogen‐atom transfer are demonstrated. In addition, a synthesis of the antidepressant fluoxetine using remote hydroxylation as a key step is presented.
Unambiguous Diagnosis of Photoinduced Charge Carrier Signatures in a Stoichiometrically Controlled Semiconducting Polymer‐Wrapped Carbon Nanotube Assembly
Authors: Olivier Jean‐Hubert , Park Jaehong , Deria Pravas , Rawson Jeff , Bai Yusong , Kumbhar Amar S. , Therien Michael J. 
Published: May 2015

AbstractSingle‐walled carbon nanotube (SWNT)‐based nanohybrid compositions based on (6,5) chirality‐enriched SWNTs ([(6,5) SWNTs]) and a chiral n‐type polymer (S‐PBN(b)‐Ph4PDI) that exploits a perylenediimide (PDI)‐containing repeat unit are reported; S‐PBN(b)‐Ph4PDI‐[(6,5) SWNT] superstructures feature a PDI electron acceptor unit positioned at 3 nm intervals along the nanotube surface, thus controlling rigorously SWNT–electron acceptor stoichiometry and organization. Potentiometric studies and redox‐titration experiments determine driving forces for photoinduced charge separation (CS) and thermal charge recombination (CR) reactions, as well as spectroscopic signatures of SWNT hole polaron and PDI radical anion (PDI−.) states. Time‐resolved pump–probe spectroscopic studies demonstrate that S‐PBN(b)‐Ph4PDI‐[(6,5) SWNT] electronic excitation generates PDI−. via a photoinduced CS reaction (τCS≈0.4 ps, ΦCS≈0.97). These experiments highlight the concomitant rise and decay of transient absorption spectroscopic signatures characteristic of the SWNT hole polaron and PDI−. states. Multiwavelength global analysis of these data provide two charge‐recombination time constants (τCR≈31.8 and 250 ps) that likely reflect CR dynamics involving both an intimately associated SWNT hole polaron and PDI−. charge‐separated state, and a related charge‐separated state involving PDI−. and a hole polaron site produced via hole migration along the SWNT backbone that occurs over this timescale.
Carbon Dioxide Activation and Reaction Induced by Electron Transfer at an Oxide–Metal Interface
Authors: Calaza Florencia , Stiehler Christian , Fujimori Yuichi , Sterrer Martin , Beeg Sebastian , Ruiz‐Oses Miguel , Nilius Niklas , Heyde Markus , Parviainen Teemu , Honkala Karoliina , Häkkinen Hannu , Freund Hans‐Joachim 
Published: May 2015

AbstractA model system has been created to shuttle electrons through a metal–insulator–metal (MIM) structure to induce the formation of a CO2 anion radical from adsorbed gas‐phase carbon dioxide that subsequently reacts to form an oxalate species. The process is completely reversible, and thus allows the elementary steps involved to be studied at the atomic level. The oxalate species at the MIM interface have been identified locally by scanning tunneling microscopy, chemically by IR spectroscopy, and their formation verified by density functional calculations.
Hyperbranched Hybridization Chain Reaction for Triggered Signal Amplification and Concatenated Logic Circuits
Authors: Bi Sai , Chen Min , Jia Xiaoqiang , Dong Ying , Wang Zonghua 
Published: May 2015

AbstractA hyper‐branched hybridization chain reaction (HB‐HCR) is presented herein, which consists of only six species that can metastably coexist until the introduction of an initiator DNA to trigger a cascade of hybridization events, leading to the self‐sustained assembly of hyper‐branched and nicked double‐stranded DNA structures. The system can readily achieve ultrasensitive detection of target DNA. Moreover, the HB‐HCR principle is successfully applied to construct three‐input concatenated logic circuits with excellent specificity and extended to design a security‐mimicking keypad lock system. Significantly, the HB‐HCR‐based keypad lock can alarm immediately if the “password” is incorrect. Overall, the proposed HB‐HCR with high amplification efficiency is simple, homogeneous, fast, robust, and low‐cost, and holds great promise in the development of biosensing, in the programmable assembly of DNA architectures, and in molecular logic operations.
Carbon Nanodots: Supramolecular Electron Donor–Acceptor Hybrids Featuring Perylenediimides
Authors: Strauss Volker , Margraf Johannes T. , Dirian Konstantin , Syrgiannis Zois , Prato Maurizio , Wessendorf Cordula , Hirsch Andreas , Clark Timothy , Guldi Dirk M. 
Published: May 2015

AbstractWe describe the formation of charge‐transfer complexes that feature electron‐donating carbon nanodots (CND) and electron‐accepting perylenediimides (PDI). The functionalities of PDIs have been selected to complement those of CNDs in terms of electrostatic and π‐stacking interactions based on oppositely charged ionic head groups and extended π‐systems, respectively. Importantly, the contributions from electrostatic interactions were confirmed in reference experiments, in which stronger interactions were found for PDIs that feature positively rather than negatively charged head groups. The electronic interactions between the components in the ground and excited state were characterized in complementary absorption and fluorescence titration assays that suggest charge‐transfer interactions in both states with binding constants on the order of 8×104 M−1 (25 L g−1). Selective excitation of the two components in ultrafast pump probe experiments gave a 210 ps lived charge‐separated state.
Drug Pharmacokinetics Determined by Real‐Time Analysis of Mouse Breath
Authors: Li Xue , Martinez‐Lozano Sinues Pablo , Dallmann Robert , Bregy Lukas , Hollmén Maija , Proulx Steven , Brown Steven A. , Detmar Michael , Kohler Malcolm , Zenobi Renato 
Published: May 2015

AbstractNoninvasive, real‐time pharmacokinetic (PK) monitoring of ketamine, propofol, and valproic acid, and their metabolites was achieved in mice, using secondary electrospray ionization and high‐resolution mass spectrometry. The PK profile of a drug influences its efficacy and toxicity because it determines exposure time and levels. The antidepressant and anaesthetic ketamine (Ket) and four Ket metabolites were studied in detail and their PK was simultaneously determined following application of different sub‐anaesthetic doses of Ket. Bioavailability after oral administration vs. intraperitoneal injection was also investigated. In contrast to conventional studies that require many animals to be sacrificed even for low‐resolution PK curves, this novel approach yields real‐time PK curves with a hitherto unmatched time resolution (10 s), and none of the animals has to be sacrificed. This thus represents a major step forward not only in animal welfare, but also major cost and time savings.
Degradation of disaccharides containing two glucose units in subcritical water
Authors: Wiboonsirikul Jintana , Nakata Keisuke , Kobayashi Takashi , Khuwijitjaru Pramote , Adachi Shuji 
Published: May 2015

AbstractDisaccharides containing two glucose units, including trehalose, cellobiose, maltose, gentiobiose, and isomaltose, were hydrolyzed in a single‐component system using subcritical water at 200–240 °C and 10 MPa. A mixture of maltose and trehalose was also hydrolyzed in a binary‐component system using subcritical water at 210 and 230 °C. The fraction of the remaining disaccharides decreased as a function of the residence time and could be expressed by the Weilbull equation at any temperature. While trehalose showed the highest resistance to hydrolysis, the other disaccharides were much less resistant to hydrolysis and their reaction rates were not much different from each other. The mixture of trehalose and maltose exhibited a reduced resistance to the hydrolysis of trehalose at high hydrolysis temperatures. In addition, glucose, which was the product of the hydrolysis, can be easily subjected to further degradation to organic acids and consequently reduces the pH of the effluent. © 2015 Curtin University of Technology and John Wiley & Sons, Ltd.
Cellulose fiber networks reinforced with glutaraldehyde–chitosan complexes
Authors: Wu Tongfei , Du Yicheng , Yan Ning , Farnood Ramin 
Published: May 2015

ABSTRACTIn this study, glutaraldehyde–chitosan complexes (GA–chitosan) were prepared and were used as functional additives to enhance the strength properties of cellulose fiber networks. The adsorption and distribution of GA–chitosan on the surface of cellulose fiber were characterized by scanning electron microscopy, X‐ray photoelectron spectroscopy and time‐of‐flight secondary ion mass spectrometry. The effects of glutaraldehyde dosage and GA–chitosan to fiber ratio on the strength properties, including wet‐strength, wet‐web strength, and dry strength, were investigated. GA–chitosan did not require high temperature curing and had good cross‐linking rates at room temperature. Samples treated with GA–chitosan exhibited significant improvements in their mechanical properties. Wet tensile index and wet‐web tensile index (both at 50% solids), and dry tensile index, were increased by about 1300, 190, and 115%, respectively. The GA–chitosan additive developed in this study provides a useful approach to prepare high‐performance value‐added specialty wood‐fiber based products. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42375.
Dynamics and thermal properties of epoxy resin cured by new diamino disiloxanes
Authors: Shi Xinxiu , Lin Xiankai , Xu Caihong , Cui Mengzhong 
Published: May 2015

ABSTRACTTwo disiloxane compounds, 3,3′‐(1,3‐dimethyl‐1,3‐diphenyl‐1,3‐disiloxanediyl)bis(benzenamine) (C1) and 4,4′‐(1,3‐dimethyl‐1,3‐diphenyl‐1,3‐disiloxanediyl)bis(benzenamine) (C2) were synthesized and used as new curing agents of DGEBA epoxy resin with an epoxy value of 0.51 (E‐51). The curing kinetics of E‐51/C1 and E‐51/C2 systems was investigated by non‐isothermal differential scanning calorimetry (DSC) analyses. The activation energy (ΔE) and the characteristic cure temperatures of the two systems were determined. The two systems have the similar activation energy. The reactivity of E‐51/C1 is higher than that of E‐51/C2. The reaction orders of E‐51/C1 and E‐51/C2 are 0.88 and 0.87, respectively, illustrating that curing reaction between the epoxy resin and curing agent (C1 or C2) is complicated. The DSC result shows that E51 cured by C2 has higher Tg; whereas thermogravimetric analysis results indicate that E51 cured by C1 has higher thermal stability. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42385.