bluuebunny/crossref_metadata_2025_split huggingface dataset:
Statistical relationships between enhanced polar cap flows and PBIs
Authors: Zou Y. , Nishimura Y. , Lyons L. R. , Donovan E. F. , Ruohoniemi J. M. , Nishitani N. , McWilliams K. A. 
Published: December 2013

AbstractPoleward boundary intensifications (PBIs) are auroral intensifications along the poleward boundary of the auroral oval and occur during all levels of geomagnetic activity. However, little is known about the triggering of PBIs. Recent case studies have indicated the existence of longitudinally localized flow channels in the polar cap near, and directed toward, the nightside open‐closed field line boundary just before PBIs. Motivated by these studies, we analyze 115 events of coordinated observations by the Time History of Events and Macroscale Interactions during Substorms all‐sky imager and Super Dual Auroral Radar Network HF radar at Rankin Inlet to determine if this polar cap flow‐PBI relationship is commonly observed. We start with isolated and intense PBIs and examine the probability of them being associated with equatorward directed polar cap flows. Our results show the association to be frequent (90%), with one‐to‐one correlations occurring in ~50% of events. Considering the limitations of the radar observations, this result indicates that PBIs are commonly correlated with polar cap flow channels directed toward, and then traversing, the open‐closed field line boundary. The flows statistically occur ~1–2 min before the PBI initiations, and the duration and width of the flows are comparable to those of the PBIs. We also perform a reverse study by starting with isolated polar cap flows and obtain similar results. The remarkably high occurrence of association between enhanced polar cap flows and PBIs indicates that enhanced mesoscale flows within the open field line region that traverse the open‐closed field line boundary are an important driver of PBI formation.
A Unique Route to Tetrasubstituted Propargylic Amines by Catalytic Markovnikov Hydroamination–Alkynylation
Authors: Pierce Conor J. , Yoo Hoseong , Larsen Catharine H. 
Published: December 2013

AbstractTetrasubstituted propargylic amines are not accessible from ketones under the many catalytic conditions reported for the synthesis of trisubstituted propargylic amines by reacting an aldehyde with an amine and alkyne. The first tandem Markovnikov hydroamination–alkynylation provides direct access to tetrasubstituted propargylic amines from an amine and alkyne via an unusual route involving no carbonyl compounds. A simple copper salt enables both catalytic cycles without ligands, promoters, co‐catalysts, solvents, or by‐products.magnified image
Study on the binding of chlorogenic acid to pepsin by spectral and molecular docking
Authors: Zeng Hua‐jin , Liang Hui‐li , You Jing , Qu Ling‐bo 
Published: December 2013

ABSTRACTThe interaction of pepsin with chlorogenic acid (CHA) was investigated using fluorescence, UV/vis spectroscopy and molecular modeling methods. Stern–Volmer analysis indicated that the fluorescence quenching of pepsin by CHA resulted from a static mechanism, and the binding constant was 1.1846 × 105 and 1.1587 × 105 L/mol at 288 and 310 K, respectively. The distance between donor (pepsin) and acceptor (CHA) was calculated to be 2.39 nm and the number of binding sites for CHA binding on pepsin was ~ 1. The results of synchronous fluorescence and three‐dimensional fluorescence showed that binding of CHA to pepsin could induce conformational changes in pepsin. Molecular docking experiments found that CHA bonded with pepsin in the area of the hydrophobic cavity with Van der Waals' forces or hydrogen bonding interaction, which were consistent with the results obtained from the thermodynamic parameter analysis. Furthermore, the binding of CHA can inhibit pepsin activity in vitro. Copyright © 2013 John Wiley & Sons, Ltd.
Modulation of CD14 and TLR4⋅MD‐2 Activities by a Synthetic Lipid A Mimetic
Authors: Cighetti Roberto , Ciaramelli Carlotta , Sestito Stefania Enza , Zanoni Ivan , Kubik Łukasz , Ardá‐Freire Ana , Calabrese Valentina , Granucci Francesca , Jerala Roman , Martín‐Santamaría Sonsoles , Jiménez‐Barbero Jesus , Peri Francesco 
Published: December 2013

AbstractMonosaccharide lipid A mimetics based on a glucosamine core linked to two fatty acid chains and bearing one or two phosphate groups have been synthesized. Compounds 1 and 2, each with one phosphate group, were practically inactive in inhibiting LPS‐induced TLR4 signaling and cytokine production in HEK‐blue cells and murine macrophages, but compound 3, with two phosphate groups, was found to be active in efficiently inhibiting TLR4 signal in both cell types. The direct interaction between compound 3 and the MD‐2 coreceptor was investigated by NMR spectroscopy and molecular modeling/docking analysis. This compound also interacts directly with the CD14 receptor, stimulating its internalization by endocytosis. Experiments on macrophages show that the effect on CD14 reinforces the activity on MD‐2⋅TLR4 because compound 3's activity is higher when CD14 is important for TLR4 signaling (i.e., at low LPS concentration). The dual targeting of MD‐2 and CD14, accompanied by good solubility in water and lack of toxicity, suggests the use of monosaccharide 3 as a lead compound for the development of drugs directed against TLR4related syndromes.
Organo‐Gallium/Indium Chalcogenide Complexes of Copper(I): Molecular Structures and Thermal Decomposition to Ternary Semiconductors
Authors: Kluge Oliver , Biedermann Ralf , Holldorf Joscha , Krautscheid Harald 
Published: December 2013

AbstractSeveral organo‐gallium/indium chalcogenide complexes of copper(I), stabilized by trialkylphosphines, were isolated, structurally characterized by using single‐crystal X‐ray diffraction, and investigated in thermolysis experiments. The syntheses with [E(Me3Si)2] (E=S, Se) as a starting material and a chalcogen source involve the elimination of volatile silyl acetate, silyl ethers, and methane from copper(I) acetate, and Group 13 metal trimethyl compounds, respectively. Chalcogenide complexes, according to the general formulas [(R3PCu)4(MeM)4E6] (1–6) and [(R3PCu)6(MeM)4M4S13] (7–9; with R=alkyl and M=Ga, In), and mixed chalcogenide–phenylchalcogenolate complexes [(iPr3PCuEPh)3(MeGaE)4] (10, 11) were isolated. The heavy atom cores of 1–6 consist of an octahedron of chalcogen atoms, interpenetrated by a cube of metal atoms. Depending on the steric demand of the phosphine ligands, two constitutions are observed; the metal atoms of the same element either forming tetrahedra, or parallelograms, respectively. This constitutional isomerism is further investigated by quantum chemical calculations. Complexes 7–9 contain a central sulfur atom, surrounded by two interpenetrating tetrahedra of Group 13 metal atoms, an octahedron of copper atoms, and an icosahedron of twelve outer sulfur atoms; the heavy atom framework of 10 and 11 is a “cut‐out” of this structure. Thermolysis experiments include thermogravimetry measurements and subsequent Rietveld phase analysis of the residues by using powder X‐ray diffraction. The homologous compounds 1, 3, 4, and 6 yield the respective crystalline ternary semiconductor material CuME2 at temperatures below 300 °C. Partial release of Me3M during the thermolysis process results in excess copper in the residue and therefore in small amounts of additional binary copper chalcogenide phases or metallic CuM alloys. Compound 8 produces nanocrystalline CuGaS2 at about 300 °C.
Synthesis of Mesoporous Platinum–Copper Films by Electrochemical Micelle Assembly and Their Electrochemical Applications
Authors: Li Cuiling , Yamauchi Yusuke 
Published: December 2013

AbstractWe have electrochemically synthesized mesoporous platinum–copper films with various compositions in an aqueous surfactant solution. By tuning the composition ratios of the platinum and copper sources in the precursor solutions, mesoporous bimetallic films with copper contents that dramatically change from 0 to 70 mol % can be successfully prepared. The obtained bimetallic films possess uniformly sized mesopores over the entire area. These mesoporous platinum–copper films are electrochemically active and show composition‐dependent catalytic activity and stability for the methanol oxidation reaction. The bimetallic mesoporous films are a promising new class of electrocatalyst for the future.
ChemInform Abstract: Subsolidus Phase Relationships and Photocatalytic Properties in the Ternary System TiO2—Bi2O3—V2O5 .
Authors: Lv Peiwen , Zheng Meng , Wang Xian , Huang Feng 
Published: December 2013

AbstractSamples for a systematic study of the TiO2—Bi2O3—V2O5 subsolidus system are prepared by calcination of pellets of mixtures of the binary oxides (550—850 °C, 3 d).
ChemInform Abstract: Microwave‐Assisted Carbohydrohalogenation of First‐Row Transition‐Metal Oxides (M: V, Cr, Mn, Fe, Co, Ni, Cu) with the Formation of Element Halides.
Authors: Berger Matthias , Neumeyer Felix , Auner Norbert 
Published: December 2013

AbstractAnhydrous transition metal chlorides and bromides MyXz (M: V, Cr, Mn, Fe, Co, Ni, Cu; X: Cl, Br) are synthesized in quantitative yields in a one‐step reaction of the metal oxides, graphite, and flowing HX under microwave irradiation (quartz‐tubes, 1000—1400 °C, 15 min).
ChemInform Abstract: High‐Pressure Synthesis, Crystal Structures, and Properties of ScRhO3 and InRhO3 Perovskites.
Authors: Belik Alexei A. , Matsushita Yoshitaka , Tanaka Masahiko , Takayama‐Muromachi Eiji 
Published: December 2013

AbstractThe title compounds are prepared from stoichiometric mixtures of In2O3 or Sc2O3 and Rh2O3 (Au capsules, 6 GPa, 1500 K, 2 h).
ChemInform Abstract: Asymmetric Copper‐Catalyzed Diels—Alder Reaction Revisited: Control of the Structure of Bis(oxazoline) Ligands.
Authors: Le Maux Paul , Dorcet Vincent , Simonneaux Gerard 
Published: December 2013

AbstractBisoxazolines bearing an ethanoanthracene backbone are reinvestigated as ligands in Cu‐catalyzed Diels—Alder reactions.
ChemInform Abstract: Alkene Chemoselectivity in Ruthenium‐Catalyzed Z‐Selective Olefin Metathesis.
Authors: Cannon Jeffrey S. , Grubbs Robert H. 
Published: December 2013

AbstractThis method yields E,Z‐dienes from dienes and terminal alkenes or internal Z‐alkenes with high chemoselectivity (with regard to the diene substrate) and complete stereoselectivity.
ChemInform Abstract: Highly Efficient Dynamic Kinetic Resolution of Secondary Aromatic Alcohols Using a Low‐Cost Solid Super Acid as a Racemization Catalyst.
Authors: Xu Gang , Wang Liang , Chen Yongjun , Cheng Yongmei , Wu Jianping , Yang Lirong 
Published: December 2013

AbstractThe dynamic kinetic resolution of alcohols (I) with 4‐chlorophenyl valerate as acyl donor proceeds in the presence of Novozym 435 and sulfated TiO2 as nano solid super acidic racemization catalyst.
ChemInform Abstract: Iodobenzene‐Catalyzed Deprotection of Hydrazones Using m‐Chloroperbenzoic Acid.
Authors: Jia Xiao‐Chuan , Li Jing , Yu Zhi‐Rui , Wang Yu‐Hu , Zhou Lei , Yu Yan‐Yan 
Published: December 2013

AbstractThis deprotection method tolerates a variety of functional groups.
ChemInform Abstract: Ruthenium‐Catalyzed Reductive Deamination and Tandem Alkylation of Aniline Derivatives.
Authors: Koreeda Tetsuro , Kochi Takuya , Kakiuchi Fumitoshi 
Published: December 2013

AbstractThese two new catalytic reactions proceed via oxidative addition of the C‐N‐bonds, followed by a β‐hydride elimination process from the ruthenium amide species.
ChemInform Abstract: Tandem Oxidative Amidation of Benzyl Alcohols with Amine Hydrochloride Salts Catalyzed by Iron Nitrate.
Authors: Ghosh Subhash Chandra , Ngiam Joyce S. Y. , Seayad Abdul M. , Tuan Dang Thanh , Johannes Charles W. , Chen Anqi 
Published: December 2013

AbstractA two‐step one‐pot process is developed to allow a tandem oxidative amidation of benzyl alcohols with amine hydrochloride salts to yield secondary and tertiary benzamides under mild conditions.
ChemInform Abstract: Development of One‐Pot Synthesis of α‐Hydroxy α‐Trifluoromethyl Amides.
Authors: Meng Zhaoyang , Butcher William E. 
Published: December 2013

AbstractA general and efficient one‐pot three‐step approach is developed to synthesize α‐hydroxy‐α‐trifluoromethyl amides from reactive aromatic halides, methyl trifluoropyruvate, and primary and secondary amines.
ChemInform Abstract: The Ru‐Catalyzed Alkylative Dearyloxylation of L‐Type 2‐Aryloxyethanols.
Authors: Weickmann Daniel , Plietker Bernd 
Published: December 2013

AbstractThe coupling of the two hydrogen‐autotransfer processes of dearyloxylation and subsequent dehydrative α‐alkylation using primary alcohols allows for the alkylative dearyloxylation of various lignin‐type model compounds.
ChemInform Abstract: Enantioselective One‐Pot Catalytic Synthesis of 4,5‐Epoxy‐3‐alkanols and 1‐Phenyl‐2,3‐epoxy‐1‐alkanols from α,β‐Unsaturated Aldehydes.
Authors: Infante Rebeca , Hernandez Yulan , Nieto Javier , Andres Celia 
Published: December 2013

AbstractOne‐pot asymmetric ethylation/epoxidation, and an unprecedented arylation/epoxidation of wide range of trisubstituted α,β‐unsaturated aldehydes is presented obtaining the title products including new enantioenriched compounds.
ChemInform Abstract: Organocatalyzed Formal [2 + 2] Cycloaddition of Ketimines with Allenoates: Facile Access to Azetidines with a Chiral Tetrasubstituted Carbon Stereogenic Center.
Authors: Takizawa Shinobu , Arteaga Fernando Arteaga , Yoshida Yasushi , Suzuki Michitaka , Sasai Hiroaki 
Published: December 2013

AbstractThe title reaction is highly E‐selective and provides azetidines in good yields with high enantioselectivities.
ChemInform Abstract: An Atom‐Economic Route to Thiophenes and 2,2′‐Bithiophenes by Intramolecular Transannulation of gem‐Dialkylthio Enynes.
Authors: Fang Guichun , Li Jichun , Wang Yeming , Gou Mingyu , Liu Qun , Li Xingqi , Bi Xihe 
Published: December 2013

AbstractThis novel, simple, and highly efficient method allows the synthesis of different functionalized thiophenes and bithiophenes.
ChemInform Abstract: Enantioselective Merger of Aminocatalysis with π‐Lewis Acid Metal Catalysis: Asymmetric Preparation of Carbo‐ and Heterocycles.
Authors: Praveen Chandrasekaran , Montaignac Benjamin , Vitale Maxime R. , Ratovelomanana‐Vidal Virginie , Michelet Veronique 
Published: December 2013

AbstractThe catalytic system is applied to the preparation of indanes with poor enantioselectivities and a wide range of pyrrolidines.
ChemInform Abstract: Synthesis of 2‐Substituted Pyrrolidines from Nitriles.
Authors: Ramachandran P. Veeraraghavan , Mitsuhashi Wataru , Nicponski Daniel R. 
Published: December 2013

AbstractAn operationally simple six‐step procedure is presented for the conversion of nitriles into pyrrolidines via reduction, allylation, hydroboration, oxidation, chlorination, and cyclization.
ChemInform Abstract: Enantioselective Cyanoethoxycarbonylation of Isatins Promoted by a Lewis Base—Broensted Acid Cooperative Catalyst.
Authors: Ogura Yoshihiro , Akakura Matsujiro , Sakakura Akira , Ishihara Kazuaki 
Published: December 2013

AbstractThis is the first enantioselective cyanoethoxycarbonylation of isatins using a simple protocol employing a Lewis base/Broensted acid cooperative catalyst.
ChemInform Abstract: Reaction of Two Differently Functionalized Oxiranes with Nickel Perchlorate: A Modular Entry to Highly Substituted 1,3‐Dioxolanes.
Authors: Chen Zuliang , Xiao Yuanjing , Zhang Junliang 
Published: December 2013

AbstractAn alternative route for the synthesis of the title compounds by using oxiranes instead of aldehydes is presented via sequential Meinwald rearrangement and cycloaddition.
ChemInform Abstract: Convenient One‐Pot Three‐Component Synthesis of Trifluoromethylated Tetrahydrobenzo[g]chromene Derivatives (IV)
Authors: Duan Yijun , Wang Xu , Xu Xiaoling , Kang Zhangping , Zhang Min , Song Liping , Deng Hongmei 
Published: December 2013

Abstract(18 examples).
ChemInform Abstract: Cobalt‐Catalyzed C—H Bond Functionalizations with Aryl and Alkyl Chlorides.
Authors: Punji Benudhar , Song Weifeng , Shevchenko Grigory A. , Ackermann Lutz 
Published: December 2013

AbstractThe title reaction proceeds under ambient temperature and low catalyst loading with excellent chemo‐ and site‐selectivities for a broad substrate scope.
ChemInform Abstract: Catalytic Asymmetric Allylic Alkylation of 3‐Arylated Piperidin‐2‐ones.
Authors: Michon Christophe , Bethegnies Aurelien , Capet Frederic , Roussel Pascal , de Filippis Arnault , Gomez‐Pardo Domingo , Cossy Janine , Agbossou‐Niedercorn Francine 
Published: December 2013

AbstractThe enantioenriched products (III) are useful intermediates for the synthesis of neurokinin antagonists.
ChemInform Abstract: One‐Pot Synthesis of Optically Enriched 2‐Piperidinones from Aliphatic Aldehydes and Cyanoacrylamides.
Authors: Kang Tai‐Ran , et al. et al. 
Published: December 2013

AbstractThe newly developed title reaction includes an organocatalytic Michael addition followed by an intramolecular hemiaminalization.
ChemInform Abstract: Isocyanide Cyclization Reactions: 4‐Methylene‐4H‐benzo[d][1,3]oxazine, 3‐Benzyl‐4‐methylene‐3,4‐dihydroquinazolines and 3‐(4‐Benzyl)‐3H‐quinazolin‐4‐ones — Experiment and Theory.
Authors: Neue Benedikt , Reiermann Ralph , Froehlich Roland , Wibbeling Birgit , Bergander Klaus , Wuerthwein Ernst‐Ulrich 
Published: December 2013

AbstractThe unexpected formation of the new class of heterocycles (III) and their oxidation products from the easily accessible starting material (I) is presented.
ChemInform Abstract: Generation of Low‐Valent Alkoxy Niobium from Nb(OEt)5 and Grignard Reagents and Their Use as Catalysts in the Cyclotrimerization of Isocyanates.
Authors: Ozaki Makoto , Obora Yasushi , Tada Yusuke , Ishii Yasutaka 
Published: December 2013

AbstractFurthermore, the title reagents can be used for the allylation reaction of 4‐octyne.
ChemInform Abstract: Gold(I)‐Catalyzed Benz[c]azepin‐4‐ol Synthesis by Intermolecular [5 + 2] Cycloaddition.
Authors: Iqbal Nassem , Fiksdahl Anne 
Published: December 2013

AbstractAu‐mediated coupling of phenylpropargyl acetals and esters with benzaldimines allows a new access to biologically important benzacepinols.
ChemInform Abstract: A Catalyst‐Free, Three‐Component Decarboxylative Coupling of Amino Acids with Aldehydes and H‐Dialkylphosphites for the Synthesis of α‐Aminophosphonates.
Authors: Kaboudin Babak , Karami Leila , Kato Jun‐ya , Aoyama Hiroshi , Yokomatsu Tsutomu 
Published: December 2013

AbstractTransition metal‐free decarboxylative coupling of proline with aldehydes and dialkyl phosphites offers a direct synthesis of aminophosphonates.
ChemInform Abstract: Cytotoxic ent‐Kaurane Diterpenoids from Isodon nervosus.
Authors: Gao You‐Heng , Wei Zhi‐Xiong , Cheng Yi , Wang Teng‐Hua , Ni Lin , Zhou Xiao‐Hong , Zhang Li‐Yuan 
Published: December 2013

AbstractThe diterpenoids rabdonervosins G‐J [(I) ‐ (IV)] are isolated from the leaves and stems of title plant.
ChemInform Abstract: Unusual Nor‐Sesquiterpene Lactone from the Fruits of Illicium henryi.
Authors: Liu Ji‐Feng , Wang Ya‐Feng , Bi Ya‐Ping , Li Hui‐Juan , Jia Lu , Bi Yue‐Feng , Zhang Yan‐Bing 
Published: December 2013

AbstractHenrylactones F (I) and G (II) as well as anislactone B (III) are isolated from the title fruit.
ChemInform Abstract: Be Squared: Expanding the Horizon of Squaric Acid‐Mediated Conjugations
Authors: Wurm Frederik R. , Klok Harm‐Anton 
Published: December 2013

AbstractReview: overview of the well‐established squaric acid diester mediated coupling reactions for glycoconjugates and recent advances to expand this very versatile reaction protocol to the modification of peptides and proteins; 101 refs.
Small‐Angle Neutron Scattering Studies of Hemoglobin Confined Inside Silica Tubes of Varying Sizes
Authors: Mandal Soumit S. , Cristiglio Viviana , Lindner Peter , Bhattacharyya Aninda J. 
Published: December 2013

AbstractIn addition to the chemical nature of the surface, the dimensions of the confining host exert a significant influence on confined protein structures; this results in immense biological implications, especially those concerning the enzymatic activities of the protein. This study probes the structure of hemoglobin (Hb), a model protein, confined inside silica tubes with pore diameters that vary by one order of magnitude (≈20–200 nm). The effect of confinement on the protein structure is probed by comparison with the structure of the protein in solution. Small‐angle neutron scattering (SANS), which provides information on protein tertiary and quaternary structures, is employed to study the influence of the tube pore diameter on the structure and configuration of the confined protein in detail. Confinement significantly influences the structural stability of Hb and the structure depends on the Si‐tube pore diameter. The high radius of gyration (Rg) and polydispersity of Hb in the 20 nm diameter Si‐tube indicates that Hb undergoes a significant amount of aggregation. However, for Si‐tube diameters greater or equal to 100 nm, the Rg of Hb is found to be in very close proximity to that obtained from the protein data bank (PDB) reported structure (Rg of native Hb=23.8 Å). This strongly indicates that the protein has a preference for the more native‐like non‐aggregated state if confined inside tubes of diameter greater or equal to 100 nm. Further insight into the Hb structure is obtained from the distance distribution function, p(r), and ab initio models calculated from the SANS patterns. These also suggest that the Si‐tube size is a key parameter for protein stability and structure.
The importance of rare species: a trait‐based assessment of rare species contributions to functional diversity and possible ecosystem function in tall‐grass prairies
Authors: Jain Meha , Flynn Dan F.B. , Prager Case M. , Hart Georgia M. , DeVan Caroline M. , Ahrestani Farshid S. , Palmer Matthew I. , Bunker Daniel E. , Knops Johannes M.H. , Jouseau Claire F. , Naeem Shahid 
Published: December 2013

AbstractThe majority of species in ecosystems are rare, but the ecosystem consequences of losing rare species are poorly known. To understand how rare species may influence ecosystem functioning, this study quantifies the contribution of species based on their relative level of rarity to community functional diversity using a trait‐based approach. Given that rarity can be defined in several different ways, we use four different definitions of rarity: abundance (mean and maximum), geographic range, and habitat specificity. We find that rarer species contribute to functional diversity when rarity is defined by maximum abundance, geographic range, and habitat specificity. However, rarer species are functionally redundant when rarity is defined by mean abundance. Furthermore, when using abundance‐weighted analyses, we find that rare species typically contribute significantly less to functional diversity than common species due to their low abundances. These results suggest that rare species have the potential to play an important role in ecosystem functioning, either by offering novel contributions to functional diversity or via functional redundancy depending on how rare species are defined. Yet, these contributions are likely to be greatest if the abundance of rare species increases due to environmental change. We argue that given the paucity of data on rare species, understanding the contribution of rare species to community functional diversity is an important first step to understanding the potential role of rare species in ecosystem functioning.