bluuebunny/crossref_metadata_2025_split huggingface dataset:
Product Differentiation by Package Size
Authors: Shreay Sanatan , Chouinard Hayley H. , McCluskey Jill J. 
Published: April 2015

ABSTRACTQuantity surcharges exist when a larger‐sized package has a higher per‐unit price than its smaller‐sized counterpart. This article argues that quantity surcharges can be explained by the fact that different sizes of the same product are imperfect substitutes and thus are differentiated products. To test this hypothesis, we utilize grocery store scanner data to estimate a demand system and the associated cross‐price elasticities. We focus our empirical investigation on canned tuna, which often exhibits quantity surcharges. A random coefficients logit demand approach is used to calculate elasticities. There is evidence to support the hypothesis that quantity surcharges in canned tuna are driven by firms catering to heterogeneous consumer preferences.
Kationische Titanocen(III)‐Komplexe für die Katalyse in Ein‐Elektronen‐Schritten
Authors: Gansäuer Andreas , Hildebrandt Sven , Michelmann Antonius , Dahmen Tobias , von Laufenberg Daniel , Kube Christian , Fianu Godfred D. , Flowers Robert A. 
Published: April 2015

AbstractDurch gezielte Ausnutzung von Lösungsmittel‐ und Anioneneffekten wurden [Cp2Ti]+‐Komplexe für die atomökonomische Katalyse in Ein‐Elektronen‐Schritten entwickelt und zum ersten Mal eingesetzt. Die kationischen Komplexe stellen besonders robuste und aktive Katalysatoren für die radikalische Arylierung von Epoxiden dar. Anhand von Cyclovoltammetrie und In‐situ‐IR‐Spektroskopie wurden Katalysatorzusammensetzungen und Reaktionskinetiken bestimmt.
Infrared Spectroscopy During Electrocatalytic Turnover Reveals the Ni‐L Active Site State During H2 Oxidation by a NiFe Hydrogenase
Authors: Hidalgo Ricardo , Ash Philip A. , Healy Adam J. , Vincent Kylie A. 
Published: April 2015

AbstractA novel in situ IR spectroscopic approach is demonstrated for the characterization of hydrogenase during catalytic turnover. E. coli hydrogenase 1 (Hyd‐1) is adsorbed on a high surface‐area carbon electrode and subjected to the same electrochemical control and efficient supply of substrate as in protein film electrochemistry during spectral acquisition. The spectra reveal that the active site state known as Ni‐L, observed in other NiFe hydrogenases only under illumination or at cryogenic temperatures, can be generated reversibly in the dark at ambient temperature under both turnover and non‐turnover conditions. The observation that Ni‐L is present at all potentials during turnover under H2 suggests that the final steps in the catalytic cycle of H2 oxidation by Hyd‐1 involve sequential proton and electron transfer via Ni‐L. A broadly applicable IR spectroscopic technique is presented for addressing electrode‐adsorbed redox enzymes under fast catalytic turnover.
polyMOFs: A Class of Interconvertible Polymer‐Metal‐Organic‐Framework Hybrid Materials
Authors: Zhang Zhenjie , Nguyen Ha Thi Hoang , Miller Stephen A. , Cohen Seth M. 
Published: April 2015

AbstractPreparation of porous materials from one‐dimensional polymers is challenging because the packing of polymer chains results in a dense, non‐porous arrangement. Herein, we demonstrate the remarkable adaptation of an amorphous, linear, non‐porous, flexible organic polymer into a three‐dimensional, highly porous, crystalline solid, as the organic component of a metal–organic framework (MOF). A polymer with aromatic dicarboxylic acids in the backbone functioned as a polymer ligand upon annealing with ZnII, generating a polymer–metal–organic framework (polyMOF). These materials break the dogma that MOFs must be prepared from small, rigid ligands. Similarly, polyMOFs contradict conventional polymer chemistry by demonstrating that linear and amorphous polymers can be readily coaxed into a highly crystalline, porous, three‐dimensional structure by coordination chemistry.
Modular Synthesis of a Dual Metal–Dual Semiconductor Nano‐Heterostructure
Authors: Amirav Lilac , Oba Fadekemi , Aloni Shaul , Alivisatos A. Paul 
Published: April 2015

AbstractReported is the design and modular synthesis of a dual metal–dual semiconductor heterostructure with control over the dimensions and placement of its individual components. Analogous to molecular synthesis, colloidal synthesis is now evolving into a series of sequential synthetic procedures with separately optimized steps. We detail the challenges and parameters that must be considered when assembling such a multicomponent nanoparticle, and their solutions. This multicomponent nanosystem, Ru‐CdSe@CdS‐Pt, was designed to achieve charge carrier separation and directional transfer across different interfaces toward two separate redox catalysts. This heterostructure may potentially serve as a nanometric closed circuit photoelectrochemical cell.
How the [NiFe4S4] Cluster of CO Dehydrogenase Activates CO2 and NCO−
Authors: Fesseler Jochen , Jeoung Jae‐Hun , Dobbek Holger 
Published: April 2015

AbstractNi,Fe‐containing CO dehydrogenases (CODHs) use a [NiFe4S4] cluster, termed cluster C, to reversibly reduce CO2 to CO with high turnover number. Binding to Ni and Fe activates CO2, but current crystal structures have insufficient resolution to analyze the geometry of bound CO2 and reveal the extent and nature of its activation. The crystal structures of CODH in complex with CO2 and the isoelectronic inhibitor NCO− are reported at true atomic resolution (dmin≤1.1 Å). Like CO2, NCO− is a μ2,η2 ligand of the cluster and acts as a mechanism‐based inhibitor. While bound CO2 has the geometry of a carboxylate group, NCO− is transformed into a carbamoyl group, thus indicating that both molecules undergo a formal two‐electron reduction after binding and are stabilized by substantial π backbonding. The structures reveal the combination of stable μ2,η2 coordination by Ni and Fe2 with reductive activation as the basis for both the turnover of CO2 and inhibition by NCO−.
Photochemical Synthesis of Ultrafine Cubic Boron Nitride Nanoparticles under Ambient Conditions
Authors: Liu Hui , Jin Peng , Xue Yan‐Ming , Dong Cunku , Li Xiang , Tang Cheng‐Chun , Du Xi‐Wen 
Published: April 2015

AbstractCubic boron nitride (c‐BN) is a super‐hard material whose hardness increases dramatically with decreasing size. However, c‐BN nanoparticles (NPs) with sizes less than 10 nm have never been obtained. Herein we report a simple strategy towards the synthesis of ultrafine c‐BN NPs with an average size of 3.5 nm. The method, under ambient conditions, exploits a laser‐induced photochemical effect and employs dioxane solution of ammonia borane (AB) as a liquid target. Meanwhile, total dehydrogenation of AB is realized by laser irradiation. Therefore, this approach shows great potential for the preparation of super‐hard NPs as well as controllable dehydrogenation.
A Fluxional Copper Acetylide Cluster in CuAAC Catalysis
Authors: Makarem Ata , Berg Regina , Rominger Frank , Straub Bernd F. 
Published: April 2015

AbstractA molecularly defined copper acetylide cluster with ancillary N‐heterocyclic carbene (NHC) ligands was prepared under acidic reaction conditions. This cluster is the first molecular copper acetylide complex that features high activity in copper‐catalyzed azide–alkyne cycloadditions (CuAAC) with added acetic acid even at −5 °C. Ethyl propiolate protonates the acetate ligands of the dinuclear precursor complex to release acetic acid and replaces one out of four ancillary ligands. Two copper(I) ions are thereby liberated to form the core of a yellow dicationic C2‐symmetric hexa‐NHC octacopper hexaacetylide cluster. Coalescence phenomena in low‐temperature NMR experiments reveal fluxionality that leads to the facile interconversion of all of the NHC and acetylide positions. Kinetic investigations provide insight into the influence of copper acetylide coordination modes and the acetic acid on catalytic activity. The interdependence of “click” activity and copper acetylide aggregation beyond dinuclear intermediates adds a new dimension of complexity to our mechanistic understanding of the CuAAC reaction.
A fluorimetric study on the interaction between a Trp‐containing beta‐strand peptide and amphiphilic polymer‐coated gold nanoparticles
Authors: Yuan Ming , Zhong Ruibo , Yun Xiaoling , Hou Jiahua , Du Qiqige , Zhao Guofen , Zhang Feng 
Published: April 2015

AbstractOwing to the inevitability of nanoparticles encountering proteins/peptides in current bio‐nano‐medicine development, it is important to know how they interact with each other in vitro before developing in vivo applications. To this end, a model de novo β‐sheet‐forming peptide and typical biocompatible nanoparticles were selected to study thermodynamic aspects of their interactions via a fluorescence quenching method. The results showed that Pep11 and AuNPs spontaneously formed conjugates, mainly driven by a coulombic interaction with a binding affinity of ~ 0.1 µM−1; the physical adsorption process was cooperative. These results deepen our quantitative understanding of nanoparticle–peptide interactions. The results may also be helpful in further nanoparticle–peptide hybrid nanofabrication and also useful for the application of nanoparticles in the treatment of amyloid diseases. Copyright © 2015 John Wiley & Sons, Ltd.
Hybrid cloud service selection strategy: Model and application of campus
Authors: Li Chunlin 
Published: April 2015

ABSTRACTThe paper proposes hybrid cloud service selection optimization scheme. Hybrid cloud service selection optimization is distributed to and performed at two levels: hybrid cloud user agent‐ hybrid cloud service agent at hybrid cloud service layer and hybrid cloud service agent‐ hybrid cloud agent at hybrid cloud resource layer. Interactions among hybrid cloud user agent, hybrid cloud service agent, public cloud agents and private cloud agents are mediated by means of market mechanisms. Two level hybrid cloud service selection optimization maximizes the interests of hybrid cloud user agents, hybrid cloud service agent, public cloud agents and private cloud agents. Hybrid cloud service selection process includes two parts: hybrid cloud service provisioning and cloud resource allocation. The paper presents a two‐level hybrid cloud service selection algorithm used to perform service provisioning and resource allocation. In the simulations, compared with other related algorithm, our proposed hybrid cloud service selection algorithms achieve the better performance with acceptable overhead. © 2015 Wiley Periodicals, Inc. Comput. Appl. Eng. Educ. Comput Appl Eng Educ 23:645–657, 2015; View this article online at wileyonlinelibrary.com/journal/cae; DOI 10.1002/cae.21634
Symmetric telepresence using robotic humanoid surrogates
Authors: Nagendran Arjun , Steed Anthony , Kelly Brian , Pan Ye 
Published: April 2015

AbstractTelepresence involves the use of virtual reality technology to facilitate apparent physical participation in distant events, including potentially performing tasks, while creating a sense of being in that location. Traditionally, such systems are asymmetric in nature where only one side (participant) is “teleported” to the remote location. In this manuscript, the authors explore the possibility of symmetric three‐dimensional telepresence where both sides (participants) are “teleported” simultaneously to each other's location; the overarching concept of symmetric telepresence in virtual environments is extended to telepresence robots in physical environments. Two identical physical humanoid robots located in UK and the USA serve as surrogates while performing a transcontinental shared collaborative task. The actions of these surrogate robots are driven by capturing the intent of the participants controlling them in either location. Participants could communicate verbally but could not see the other person or the remote location while performing the task. The effectiveness of gesturing along with other observations during this preliminary experiment is presented. Results reveal that the symmetric robotic telepresence allowed participants to use and understand gestures in cases where they would otherwise have to describe their actions verbally. Copyright © 2015 John Wiley & Sons, Ltd.
Interactive tree modeling and deformation with collision detection and avoidance
Authors: Kim Yong‐Joon , Woo Jong‐Hwa , Kim Myung‐Soo , Elber Gershon 
Published: April 2015

AbstractWe present an interactive tree modeling and deformation system that supports an efficient collision detection and avoidance using a bounding volume hierarchy of sweep surfaces. Starting with conventional tree models (given as meshes), we convert them into sweep surfaces and deform their branches interactively while detecting and avoiding collisions with many other branches. Multiple tree models (sharing the same topology) can be generated with great ease using this sweep‐based approach, and they can serve as a basis for the generation of a multiparameter family of trees. We demonstrate the effectiveness of our approach in an automatic generation of similar trees, the colonization of trees to form a forest, and the tree growth, aging, and withering simulations. Copyright © 2015 John Wiley & Sons, Ltd.
Conservative therapy with a gonadotropin‐releasing hormone agonist for a uterine arteriovenous malformation in a patient with congenital heart disease
Authors: Katano Kinue , Takeda Yutaka , Sugiura‐Ogasawara Mayumi 
Published: April 2015

Key Clinical MessageUterine arteriovenous malformation (AVM) is rare but it can cause life‐threatening genital bleeding. Conservative therapy with GnRHa can be a useful option for treating a uterine AVM presenting with a congenital heart disease shunt in hemodynamically stable patients.
Correlation between Thermal Properties and Chemical Composition of Palm Oil Top Olein Fractions
Authors: Huang Xin , Wang Jingkang , Ouyang Jinbo , Hao Hongxun , Wang Yongli , Gao Yuan , Yin Qiuxiang , Bao Ying 
Published: April 2015

AbstractA multistep dry fractionation method for modification of palm oil was adopted to achieve a high iodine value (IV) of the obtained palm olein, herein denoted as top olein. The effect of the composition of palm oil top olein on the IV and on the crystallization properties was analyzed in detail. Thermal properties of a series of olein and stearin fractions were evaluated by means of differential scanning calorimetry upon cooling. The composition of triacylglycerols in the products was investigated by high‐performance liquid chromatography. IV analysis was carried out to measure the degree of unsaturation in these oil samples. Finally, an innovative and reliable method was developed to determine the IV of palm oils by relating the thermal properties with IV. The results agree well with those obtained by the traditional American Oil Chemists' Society method.
Analytic Setup for Multicomponent High‐Pressure Phase Equilibria via Dual Online Gas Chromatography
Authors: Fourie Frederick C. v. N. , Schwarz Cara E. , Knoetze Johannes H. 
Published: April 2015

AbstractA high‐pressure analytic phase equilibria setup, capable of operation at 150 °C and 30 MPa, was developed. The variable‐volume view cell contains two height‐adjustable samplers enabling simultaneous sampling from two phases. Concurrent analysis of both samples was performed with dual online gas chromatography (GC). The GC comprises two inlets, four columns, two switch valves, and three detectors, arranged in parallel pathways. Quantitative detector calibrations were used. The setup was validated by sampling from a one‐phase ternary of known composition, and comparison with binary and ternary literature data. The setup produces accurate phase composition data for supercritical systems and is well‐suited to handle mixture constituents ranging from volatile gases to mid‐length hydrocarbons.
Protein Composite Materials by Crystallization: Product and Process Design
Authors: Frohberg Patrick , Ulrich Joachim 
Published: April 2015

AbstractThe product and process design of protein composite materials continuously produced by reactive extrusion are studied in detail. A suitable process design and operating window are presented. Potassium nitrate (KNO3) was used as a model additive and as a tool for modifying the physiochemical properties of the extruded protein films. The crystalline structures were identified and correlated to the tensile properties of the films. Uniformly distributed trigonal phase‐III KNO3 crystals were observed within the film, which led to significantly higher elongation values of the films. Appropriate downstream operations are able to prevent the undesired polymorph transition to the orthorhombic phase II of KNO3 which would strongly reduce the mechanical performance.
Growth and Dissolution Kinetics of A and B Polymorphs of L‐Histidine
Authors: Wantha Lek , Flood Adrian E. 
Published: April 2015

AbstractThe growth rate of the stable polymorph A and the dissolution rate of the unstable polymorph B of L‐histidine (L‐his) in aqueous solution were experimentally determined at varying temperatures. The growth and dissolution kinetics were measured by means of desupersaturation and deundersaturation techniques, respectively. Both the growth and dissolution rates increase with higher temperature. At all temperatures studied, the dissolution rate of form B is faster than the growth rate of form A, indicating that the solution‐mediated transformation of the polymorphs of L‐his is likely to be controlled by the growth rate of form A. Both kinetics of the polymorphs of L‐his will be used to characterize the polymorphic transformations and the overall crystallization rate of L‐his.
In Situ Formation of a MoS2‐Based Inorganic–Organic Nanocomposite by Directed Thermal Decomposition
Authors: Djamil John , Segler Stefan A. W. , Bensch Wolfgang , Schürmann Ulrich , Deng Mao , Kienle Lorenz , Hansen Sven , Beweries Torsten , von Wüllen Leo , Rosenfeldt Sabine , Förster Stephan , Reinsch Helge 
Published: April 2015

AbstractNanocomposites based on molybdenum disulfide (MoS2) and different carbon modifications are intensively investigated in several areas of applications due to their intriguing optical and electrical properties. Addition of a third element may enhance the functionality and application areas of such nanocomposites. Herein, we present a facile synthetic approach based on directed thermal decomposition of (Ph4P)2MoS4 generating MoS2 nanocomposites containing carbon and phosphorous. Decomposition at 250 °C yields a composite material with significantly enlarged MoS2 interlayer distances caused by in situ formation of Ph3PS bonded to the MoS2 slabs through MoS bonds and (Ph4P)2S molecules in the van der Waals gap, as was evidenced by 31P solid‐state NMR spectroscopy. Visible‐light‐driven hydrogen generation demonstrates a high catalytic performance of the materials.
Cobalt‐Catalyzed Intermolecular C(sp2)O Cross‐Coupling
Authors: Kundu Debasish , Tripathy Manisha , Maity Pintu , Ranu Brindaban C. 
Published: April 2015

AbstractCobalt(II)‐catalyzed C(sp2)O cross‐coupling between aryl/heteroaryl alcohols and vinyl/aryl halides in the presence of CuI has been achieved under ligand‐free conditions. In this reaction, copper plays a significant role in transmetalation rather than being directly involved in the CO coupling. This unique Co/Cu‐dual catalyst system provides an easy access to a library of aryl–vinyl, heteroaryl–styryl, aryl–aryl, and heteroaryl–heteroaryl ethers in the absence of any ligand or additive.
Drug Metabolism by Cytochrome P450 Enzymes: What Distinguishes the Pathways Leading to Substrate Hydroxylation Over Desaturation?
Authors: Ji Li , Faponle Abayomi S. , Quesne Matthew G. , Sainna Mala A. , Zhang Jing , Franke Alicja , Kumar Devesh , van Eldik Rudi , Liu Weiping , de Visser Sam P. 
Published: April 2015

AbstractCytochrome P450 enzymes are highly versatile biological catalysts in our body that react with a broad range of substrates. Key functions in the liver include the metabolism of drugs and xenobiotics. One particular metabolic pathway that is poorly understood relates to the P450 activation of aliphatic groups leading to either hydroxylation or desaturation pathways. A DFT and QM/MM study has been carried out on the factors that determine the regioselectivity of aliphatic hydroxylation over desaturation of compounds by P450 isozymes. The calculations establish multistate reactivity patterns, whereby the product distributions differ on each of the spin‐state surfaces; hence spin‐selective product formation was found. The electronic and thermochemical factors that determine the bifurcation pathways were analysed and a model that predicts the regioselectivity of aliphatic hydroxylation over desaturation pathways was established from valence bond and molecular orbital theories. Thus, the difference in energy of the OH versus the OC bond formed and the π‐conjugation energy determines the degree of desaturation products. In addition, environmental effects of the substrate binding pocket that affect the regioselectivities were identified. These studies imply that bioengineering P450 isozymes for desaturation reactions will have to include modifications in the substrate binding pocket to restrict the hydroxylation rebound reaction.
Nickel N‐Heterocyclic Carbene Catalyzed CC Bond Formation: A New Route to Aryl Ketones
Authors: Gu Li‐Jun , Jin Cheng , Zhang Hong‐Tao 
Published: April 2015

AbstractA novel nickel N‐heterocyclic carbene catalyzed cross‐coupling reaction of aryl aldehydes with boronic esters for the synthesis of aryl ketones was developed. This reaction provides a mild, practical method toward aryl ketones, which are versatile intermediates and building blocks in organic synthesis.
Crystalline Cyclic (Alkyl)(amino)carbene‐tetrafluoropyridyl Radical
Authors: Styra Steffen , Melaimi Mohand , Moore Curtis E. , Rheingold Arnold. L. , Augenstein Timo , Breher Frank , Bertrand Guy 
Published: April 2015

AbstractA stable cyclic (alkyl)(amino)carbene (CAAC) 1 inserts into the para‐CF bond of pentafluoropyridine, and after fluoride abstraction, the iminium‐pyridyl adduct [3]+ was isolated. A cyclic voltammetry study shows a reversible three‐state redox system involving [3]+, [3]⋅, and [3]−. The CAAC‐pyridyl radical [3]⋅, obtained by reduction of [3]+ with magnesium, has been spectroscopically and crystallographically characterized. In contrast to the lack of π communication between the CAAC and the pyridine units in cation [3]+, the unpaired electron of [3]⋅ is delocalized over an extended π system involving both heterocycles.