bluuebunny/crossref_metadata_2025_split huggingface dataset:
Poly(N‐vinylpyrrolidone)‐Decorated Reduced Graphene Oxide with ZnO Grown In Situ as a Cathode Buffer Layer for Polymer Solar Cells
Authors: Hu Ting , Chen Lie , Yuan Kai , Chen Yiwang 
Published: October 2014

AbstractA ZnO@reduced graphene oxide–poly(N‐vinylpyrrolidone) (ZnO@RGO‐PVP) nanocomposite, prepared by in situ growth of ZnO nanoparticles on PVP‐decorated RGO (RGO‐PVP) was developed as a cathode buffer layer for improving the performance of polymer solar cells (PSCs). PVP not only favors homogeneous distribution of the RGO through the strong π–π interactions between graphene and PVP molecules, but also acts as a stabilizer and bridge to control the in situ growth of sol–gel‐derived ZnO nanoparticles on the surface of the graphene. At the same time, RGO provides a conductive connection for independent dispersion of ZnO nanoparticles to form uniform nanoclusters with fewer domain boundaries and surface traps. Moreover, the LUMO level of ZnO is effectively improved by modification with RGO‐PVP. Compared to bare ZnO, a ZnO@RGO‐PVP cathode buffer layer substantially reduces the recombination of carriers, increases the electrical conductivity, and enhances electron extraction. Consequently, the power conversion efficiency of an inverted device based on thieno[3,4‐b]thiophene/benzodithiophene (PTB7):[6,6]‐phenyl C71‐butyric acid methyl ester (PC71BM) with ZnO@RGO‐PVP as cathode buffer layer was greatly improved to 7.5 % with improved long‐term stability. The results reveal that ZnO@RGO‐PVP is universally applicable as a cathode buffer layer for improving the performance of PSCs.
Sulfur‐Impregnated Core–Shell Hierarchical Porous Carbon for Lithium–Sulfur Batteries
Authors: Zhang Fei‐Fei , Huang Gang , Wang Xu‐Xu , Qin Yu‐Ling , Du Xin‐Chuan , Yin Dong‐Ming , Liang Fei , Wang Li‐Min 
Published: October 2014

AbstractCore–shell hierarchical porous carbon spheres (HPCs) were synthesized by a facile hydrothermal method and used as host to incorporate sulfur. The microstructure, morphology, and specific surface areas of the resultant samples have been systematically characterized. The results indicate that most of sulfur is well dispersed over the core area of HPCs after the impregnation of sulfur. Meanwhile, the shell of HPCs with void pores is serving as a retard against the dissolution of lithium polysulfides. This structure can enhance the transport of electron and lithium ions as well as alleviate the stress caused by volume change during the charge–discharge process. The as‐prepared HPC‐sulfur (HPC‐S) composite with 65.3 wt % sulfur delivers a high specific capacity of 1397.9 mA h g−1 at a current density of 335 mA g−1 (0.2 C) as a cathode material for lithium–sulfur (Li‐S) batteries, and the discharge capacity of the electrode could still reach 753.2 mA h g−1 at 6700 mA g−1 (4 C). Moreover, the composite electrode exhibited an excellent cycling capacity of 830.5 mA h g−1 after 200 cycles.
Reversible Reduction of Oxatriphyrin(3.1.1)—Adjusting the Coordination Abilities to the Central Ion
Authors: Pawlicki Miłosz , Kędzia Aneta , Bykowski Dominik , Latos‐Grażyński Lechosław 
Published: October 2014

AbstractFuran‐fused oxatriphyrin(3.1.1) acts as a ligand towards boron(III), phosphorous(III), and phosphorous(V) ions. The coordination abilities are adjusted by changes of the oxidation state. Two coordination modes are possible, depending on the central‐ion entrapped in the oxatriphyrin(3.1.1) environment. A free base, structurally similar to the complexes, can be easily obtained by regioselective reduction. The resulting molecules are highly emissive after conversion into a phlorin‐like oxatriphyrin(3.1.1) frame (NON donors), and show chiral activity caused by the presence of a tetrahedral carbon.
Podand‐Based Dimeric Chromium(III)–Salen Complex for Asymmetric Henry Reaction: Cooperative Catalysis Promoted by Complexation of Alkali Metal Ions
Authors: Ouyang Guang‐Hui , He Yan‐Mei , Fan Qing‐Hua 
Published: October 2014

AbstractA new kind of podand‐based dimeric salen ligand was synthesized, and its association with potassium cations was investigated by 1H NMR spectroscopy. The corresponding CrIII–salen dimer was assembled by a supramolecular host–guest self‐assembly process and was then used as a catalyst in highly efficient and enantioselective asymmetric Henry reactions. Regulation by KBArF (BArF=[3,5‐(CF3)2C6H3]4B) led to remarkable improvements in yield (by up to 58 %) and enantioselectivity (for example, from 80 % ee to 96 % ee).
Chemoselective Reductive Nucleophilic Addition to Tertiary Amides, Secondary Amides, and N‐Methoxyamides
Authors: Nakajima Minami , Oda Yukiko , Wada Takamasa , Minamikawa Ryo , Shirokane Kenji , Sato Takaaki , Chida Noritaka 
Published: October 2014

AbstractAs the complexity of targeted molecules increases in modern organic synthesis, chemoselectivity is recognized as an important factor in the development of new methodologies. Chemoselective nucleophilic addition to amide carbonyl centers is a challenge because classical methods require harsh reaction conditions to overcome the poor electrophilicity of the amide carbonyl group. We have successfully developed a reductive nucleophilic addition of mild nucleophiles to tertiary amides, secondary amides, and N‐methoxyamides that uses the Schwartz reagent [Cp2ZrHCl]. The reaction took place in a highly chemoselective fashion in the presence of a variety of sensitive functional groups, such as methyl esters, which conventionally require protection prior to nucleophilic addition. The reaction will be applicable to the concise synthesis of complex natural alkaloids from readily available amide groups.
Novel λ3‐Iodane‐Based Functionalization of Synthetic Carbon Allotropes (SCAs)—Common Concepts and Quantification of the Degree of Addition
Authors: Hof Ferdinand , Schäfer Ricarda A. , Weiss Cornelius , Hauke Frank , Hirsch Andreas 
Published: October 2014

AbstractThe covalent functionalization of carbon allotropes represents a main topic in the growing field of nano materials. However, the development of functional architectures is impeded by the intrinsic polydispersibility of the respective starting material, the unequivocal characterization of the introduced functional moieties, and the exact determination of the degree of functionalization. Based on a novel carbon allotrope functionalization reaction, utilizing λ3‐iodanes as radical precursor systems, we were able to demonstrate the feasibility to separate and to quantify thermally detached functional groups, formerly covalently linked to carbon nanotubes and graphene through thermogravimetric GC‐MS.
Enantioselective Total Synthesis of the Lignan (+)‐Linoxepin
Authors: Tietze Lutz F. , Clerc Jérôme , Biller Simon , Duefert Svenia‐C. , Bischoff Matthias 
Published: October 2014

AbstractAn enantioselective total synthesis of the natural (+)‐linoxepin (1) was accomplished in eleven steps from bromovanin (24). Key steps are a domino carbopalladation/ Mizoroki–Heck reaction with the formation of a pentacyclic system, an asymmetric hydroboration as well as an oxidative lactonization.
Precise Tuning of the Charge Transfer Kinetics and Catalytic Properties of MoS2 Materials via Electrochemical Methods
Authors: Chia Xinyi , Ambrosi Adriano , Sedmidubský David , Sofer Zdeněk , Pumera Martin 
Published: October 2014

AbstractMoS2 has become particularly popular for its catalytic properties towards the hydrogen evolution reaction (HER). It has been shown that the metallic 1T phase of MoS2, obtained by chemical exfoliation after lithium intercalation, possesses enhanced catalytic activity over the semiconducting 2H phase due to the improved conductivity properties which facilitate charge‐transfer kinetics. Here we demonstrate a simple electrochemical method to precisely tune the electron‐transfer kinetics as well as the catalytic properties of both exfoliated and bulk MoS2‐based films. A controlled reductive or oxidative electrochemical treatment can alter the surface properties of the film with consequently improved or hampered electrochemical and catalytic properties compared to the untreated film. Density functional theory calculations were used to explain the electrochemical activation of MoS2. The electrochemical tuning of electrocatalytic properties of MoS2 opens the doors to scalable and facile tailoring of MoS2‐based electrochemical devices.
Screen‐Printed Calcium–Birnessite Electrodes for Water Oxidation at Neutral pH and an “Electrochemical Harriman Series”
Authors: Lee Seung Y. , González‐Flores Diego , Ohms Jonas , Trost Tim , Dau Holger , Zaharieva Ivelina , Kurz Philipp 
Published: October 2014

AbstractA mild screen‐printing method was developed to coat conductive oxide surfaces (here: fluorine‐doped tin oxide) with micrometer‐thick layers of presynthesized calcium manganese oxide (Ca–birnessite) particles. After optimization steps concerning the printing process and layer thickness, electrodes were obtained that could be used as corrosion‐stable water‐oxidizing anodes at pH 7 to yield current densities of 1 mA cm−2 at an overpotential of less than 500 mV. Analyses of the electrode coatings of optimal thickness (≈10 μm) indicated that composition, oxide phase, and morphology of the synthetic Ca–birnessite particles were hardly affected by the screen‐printing procedure. However, a more detailed analysis by X‐ray absorption spectroscopy revealed small modifications of both the Mn redox state and the structure at the atomic level, which could affect functional properties such as proton conductivity. Furthermore, the versatile new screen‐printing method was used for a comparative study of various transition‐metal oxides concerning electrochemical water oxidation under “artificial leaf conditions” (neutral pH, fairly low overpotential and current density), for which a general activity ranking of RuO2>Co3O4≈(Ca)MnOx≈NiO was observed. Within the group of screened manganese oxides, Ca–birnessite performed better than “Mn‐only materials” such as Mn2O3 and MnO2.
Phylogeography and palaeodistribution modelling of Nassauvia subgenus Strongyloma (Asteraceae): exploring phylogeographical scenarios in the Patagonian steppe
Authors: Nicola Marcela V. , Sede Silvana M. , Pozner Raúl , Johnson Leigh A. 
Published: October 2014

AbstractThe Patagonian steppe is an immense, cold, arid region, yet phylogeographically understudied. Nassauvia subgen. Strongyloma is a characteristic element of the steppe, exhibiting a continuum of morphological variation. This taxon provides a relevant phylogeographical model not only to understand how past environmental changes shaped the genetic structure of its populations, but also to explore phylogeographical scenarios at the large geographical scale of the Patagonian steppe. Here, we (1) assess demographic processes and historical events that shaped current geographic patterns of haplotypic diversity; (2) analyze hypotheses of isolation in refugia, fragmentation of populations, and/or colonization of available areas during Pleistocene glaciations; and (3) model extant and palaeoclimatic distributions to support inferred phylogeographical patterns. Chloroplast intergenic spacers, rpl32–trnL and trnQ–5′rps16, were sequenced for 372 individuals from 63 populations. Nested clade analysis, analyses of molecular variance, and neutrality tests were performed to assess genetic structure and range expansion. The present potential distribution was modelled and projected onto a last glacial maximum (LGM) model. Of 41 haplotypes observed, ten were shared among populations associated with different morphological variants. Populations with highest haplotype diversity and private haplotypes were found in central‐western and south‐eastern Patagonia, consistent with long‐term persistence in refugia during Pleistocene. Palaeomodelling suggested a shift toward the palaeoseashore during LGM; new available areas over the exposed Atlantic submarine platform were colonized during glaciations with postglacial retraction of populations. A scenario of fragmentation and posterior range expansion may explain the observed patterns in the center of the steppe, which is supported by palaeomodelling. Northern Patagonian populations were isolated from southern populations by the Chubut and the Deseado river basins during glaciations. Pleistocene glaciations indirectly impacted the distribution, demography, and diversification of subgen. Strongyloma through decreased winter temperatures and water availability in different areas of its range.
Synthesis of Isotopically Labelled Oligoprenyl Diphosphates and Their Application in Mechanistic Investigations of Terpene Cyclases
Authors: Citron Christian A. , Rabe Patrick , Barra Lena , Nakano Chiaki , Hoshino Tsutomu , Dickschat Jeroen S. 
Published: October 2014

AbstractA flexible, efficient and robust method for the synthesis of isotopically labelled oligoprenyl diphosphates was developed. The method makes use of just a few building blocks (acetone, triethyl phosphonoacetate, and ethyl acetoacetate) from which several isotopomers with deuterium or 13C‐labelling are commercially available or can be easily obtained by synthesis. Besides these building blocks, a few deuterated reagents were used for the introduction of deuterium labelling. Furthermore, the synthesis of [14‐2H]geranylgeranyl diphosphate is reported. The material was used for a stereochemical analysis of the cyclisation reaction catalysed by tuberculosinyl diphosphate synthase from Mycobacterium tuberculosis.
Synthesis of Vicinal Diketoses by Using a Metathesis–Hydroxylation–Oxidation Sequence
Authors: Menzel Melchior , Ziegler Thomas 
Published: October 2014

AbstractSymmetrical vicinal diuloses were prepared from 2,3:4,5‐di‐O‐isopropylidene‐D‐arabinose and ‐L‐arabinose by using methyltriphenylphosphonium bromide to convert both enantiomers into the corresponding 1,2‐dideoxy‐3,4:5,6‐di‐O‐isopropylidene‐arabino‐hex‐1‐enitols D‐5 and L‐5. The metathesis reactions of D‐5 with itself and with L‐5, respectively, by using the Hoveyda–Grubbs catalyst gave diastereomeric dec‐5‐enitols DD‐6 and DL‐6, which were dihydroxylated with osmium tetroxide to give 1,2:3,4:7,8:9,10‐tetra‐O‐isopropylidene‐protected decitols DD‐7 and DL‐7. Swern oxidation of the decitols afforded isopropylidene‐protected deco‐5,6‐diuloses DD‐8 and DL‐8, which gave unprotected deco‐5,6‐diuloses DD‐9 and DL‐9 upon acidic cleavage of the isopropylidene groups. The structures of both diastereomers were confirmed by NMR spectroscopy and X‐ray crystal structure analysis.
From intrapsychic to ecological theories in social psychology: Outlines of a functional theory approach
Authors: Fiedler Klaus 
Published: October 2014

AbstractSocial psychology is facing a major developmental task, which is not primarily one of achieving larger data samples and stricter significance testing. What is needed, rather, is an improvement in logic of science and powerful theorizing. The starting point of this article is a critical appraisal that the intrapsychic concepts (motives, attitudes, and explicit and implicit goals) that are the major focus of social–psychological theories lack in explanatory power because they are too close to the effects (actions, judgments, and decisions) they are intended to explain. To overcome this apparent weakness (compared with neuroscience or genetics), it is proposed that more powerful theories should relate social cognition and behavior to more distant variables in the environment. A functional analysis reveals that intrapsychic processes are multiply predetermined by extrapsychic, environmental constraints. The theoretical value and fertility of the proposed ecological functionalism are illustrated with reference to three areas of empirical research: sampling approaches to understanding biases in judgment and decision making; strategic influences on priming effects within a functional analysis of adaptive behavior; and the impact of verbal and symbolic communication constraints on the construction of attributions, stereotypes, and culture. Copyright © 2014 John Wiley & Sons, Ltd.
Seismic response of a case study soft story frame retrofitted using a GIB system
Authors: Agha Beigi Hossein , Christopoulos Constantin , Sullivan Timothy , Calvi Michele 
Published: October 2014

SummaryThis paper presents results from a numerical investigation into the seismic retrofit of a soft story frame using a novel gapped‐inclined brace (GIB) system. The GIB system consists of a pinned brace and a gap element that is added to the first story columns of the frame. The inclusion of GIB elements in addition to increasing the lateral capacity of columns at the first story increases the post‐yield stiffness ratio of the system and reduces the P‐delta effects on the columns, while not increasing the first story lateral resistance or stiffness. This allows for the isolating benefits of the soft story to protect the upper floors of the structure from damage while avoiding excessive deformations and reducing the propensity for collapse.A six‐story RC frame with masonry infills on all floors except for the first floor is studied. The dynamic response of the retrofitted building using the GIB system is investigated numerically and is compared with the response of the original un‐retrofitted building and the same building in which masonry infills are added to the first story to mitigate the soft story response.Results from the nonlinear time‐history analyses indicate that the GIB system could provide a reliable seismic retrofit mechanism for soft story buildings, which greatly reduces the likelihood of collapse by increasing the displacement capacity of the soft storey and by reducing P‐delta effects, while minimizing the overall damage and losses in the building by taking advantages of the isolation that is provided by the soft story to the rest of the structure located above. Copyright © 2014 John Wiley & Sons, Ltd.
Development of empirical and analytical fragility functions using kernel smoothing methods
Authors: Noh Hae Young , Lallemant David , Kiremidjian Anne S. 
Published: October 2014

SummaryFragility functions that define the probabilistic relationship between structural damage and ground motion intensity are an integral part of performance‐based earthquake engineering or seismic risk analysis. This paper introduces three approaches based on kernel smoothing methods for developing analytical and empirical fragility functions. A kernel assigns a weight to each data that is inversely related to the distance between the data value and the input of the fragility function of interest. The kernel smoothing methods are, therefore, non‐parametric forms of data interpolation. These methods enable the implicit treatment of uncertainty in either or both of ground motion intensity and structural damage without making any assumption about the shape of the resulting fragility functions. They are particularly beneficial for sparse, noisy, or non‐homogeneous data sets. For illustration purposes, two types of data are considered. The first is a set of numerically simulated responses for a four‐story steel moment‐resisting frame, and the second is a set of field observations collected after the 2010 Haiti earthquake. The results demonstrate that these methods can develop continuous representations of fragility functions without specifying their functional forms and treat sparse data sets more efficiently than conventional data binning and parametric curve fitting methods. Moreover, various uncertainty analyses are conducted to address the issues of over‐fitting, bias, and confidence intervals. Copyright © 2014 John Wiley & Sons, Ltd.
Raman spectroscopy analysis of lipid droplets content, distribution and saturation level in Non‐Alcoholic Fatty Liver Disease in mice
Authors: Kochan Kamila , Maslak Edyta , Krafft Christoph , Kostogrys Renata , Chlopicki Stefan , Baranska Malgorzata 
Published: October 2014

Non‐Alcoholic Fatty Liver Disease (NAFLD) is a common liver disorder, characterized by an excessive lipids deposition within the hepatic tissue. Due to the lack of clear‐cut symptoms and optimal diagnostic method, the actual prevalence of NAFLD and its pathogenesis remains unclear, especially in the early stages of progression. In the presented work confocal Raman microspectroscopy was used to investigate alterations in the chemical composition of the NAFLD‐affected liver. We have investigated two NAFLD models, representative for macrovesicular and microvesicular steatosis, induced by High Fat Diet (60 kcal %) and Low Carbohydrate High Protein Diet (LCHP), respectively. In both models we confirmed the development of NAFLD, manifested by the presence of lipid droplets (LDs), but of different sizes. Model of macrovesicular steatosis was characterized by large LDs, whereas in the microvesicular steatosis model small droplets were found. In both models, however, we observed a significant decrease in the degree of unsaturation of lipids, in comparison to the control. In addition, for both models, the impact of medical treatment with selected drugs (perindopril and nicotinic acid, respectively) was tested, indicating a significant influence of medicine not only on the occurrence and size of the droplets, but also on their composition. Inboth cases the drug treatment resulted in an increase of the degree of unsaturation of lipids forming droplets. Confocal Raman microspectroscopy was proven to be a powerful tool providing detailed insight into selected areas of hepatic tissue, following the NAFLD pathogenesis and diagnostic potential of the applied drugs.
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Osteoblast response to the surface of amino acid‐functionalized hydroxyapatite
Authors: Lee Wing‐Hin , Loo Ching‐Yee , Chrzanowski Wojciech , Rohanizadeh Ramin 
Published: October 2014

AbstractInteractions between proteins and the surface of biomaterials are crucial for the biological function and success of materials implanted in the human body. In this study, hydroxyapatite (HA) with negative and positive surface charges were fabricated by functionalizing the HA surface with acidic or basic amino acids. The influence of HA surface charge on protein adsorption and cell activities was studied. The crystallinity, morphology, and surface charge of amino acid‐functionalized HA (AA‐HA) particles and the stability of amino acids on the HA surface were determined. Both AA‐HA and unmodified HA were studied for their capacity to adsorb proteins present in biological medium. The results showed that the presence of glutamic acid; Glu (acidic amino acids) and arginine; Arg (basic amino acids) on the HA surface resulted in higher protein adsorption owing to stronger electrostatic attraction between the HA particles and the proteins in medium. Functionalizing HA with Glu and Arg significantly promoted osteoblast adhesion on the surface of treated HA. No significant differences in cell proliferation between negatively and positively charged HA was observed. Significantly higher alkaline phosphatase (ALP) activity of osteoblasts on both charged surfaces was seen as compared to the unmodified HA. The study demonstrated that immobilization of amino acids (Glu and Arg) on the surface of HA promoted osteoblast proliferation and ALP activity. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 2150–2160, 2015.
A Green Strategy to Prepare Warfarin‐like Compounds Catalyzed by Zirconium Oxychloride
Authors: Khodabakhshi Saeed , Abbasabadi Masoud Khaleghi , Baghrnejad Mojtaba , Marahel Farzaneh 
Published: October 2014

AbstractA one‐pot, three‐component synthesis of warfarin‐like compounds from the reaction of benzamide, aryl glyoxal and 4‐hydroxycoumarin is described. Zirconium oxychloride octahydrate catalyzed the reactions efficiently under solvent‐free conditions to yield desired products in good yields.