bluuebunny/crossref_metadata_2025_split huggingface dataset:
Controlled Synthesis of Fe3O4/ZIF‐8 Nanoparticles for Magnetically Separable Nanocatalysts
Authors: Pang Fei , He Mingyuan , Ge Jianping 
Published: March 2015

AbstractFe3O4/ZIF‐8 nanoparticles were synthesized through a room‐temperature reaction between 2‐methylimidazolate and zinc nitrate in the presence of Fe3O4 nanocrystals. The particle size, surface charge, and magnetic loading can be conveniently controlled by the dosage of Zn(NO3)2 and Fe3O4 nanocrystals. The as‐prepared particles show both good thermal stability (stable to 550 °C) and large surface area (1174 m2g−1). The nanoparticles also have a superparamagnetic response, so that they can strongly respond to an external field during magnetic separation and disperse back into the solution after withdrawal of the magnetic field. For the Knoevenagel reaction, which is catalyzed by alkaline active sites on external surface of catalyst, small Fe3O4/ZIF‐8 nanoparticles show a higher catalytic activity. At the same time, the nanocatalysts can be continuously used in multiple catalytic reactions through magnetic separation, activation, and redispersion with little loss of activity.
Unusually Short Chalcogen Bonds Involving Organoselenium: Insights into the Se–N Bond Cleavage Mechanism of the Antioxidant Ebselen and Analogues
Authors: Thomas Sajesh P. , Satheeshkumar K. , Mugesh Govindasamy , Guru Row T. N. 
Published: March 2015

AbstractStructural studies on the polymorphs of the organoselenium antioxidant ebselen and its derivative show the potential of organic selenium to form unusually short Se⋅⋅⋅O chalcogen bonds that lead to conserved supramolecular recognition units. Se⋅⋅⋅O interactions observed in these polymorphs are the shortest such chalcogen bonds known for organoselenium compounds. The FTIR spectral evolution characteristics of this interaction from solution state to solid crystalline state further validates the robustness of this class of supramolecular recognition units. The strength and electronic nature of the Se⋅⋅⋅O chalcogen bonds were explored using high‐resolution X‐ray charge density analysis and atons‐in‐molecules (AIM) theoretical analysis. A charge density study unravels the strong electrostatic nature of Se⋅⋅⋅O chalcogen bonding and soft‐metal‐like behavior of organoselenium. An analysis of the charge density around SeN and SeC covalent bonds in conjunction with the Se⋅⋅⋅O chalcogen bonding modes in ebselen and its analogues provides insights into the mechanism of drug action in this class of organoselenium antioxidants. The potential role of the intermolecular Se⋅⋅⋅O chalcogen bonding in forming the intermediate supramolecular assembly that leads to the bond cleavage mechanism has been proposed in terms of electron density topological parameters in a series of molecular complexes of ebselen with reactive oxygen species (ROS).
Hydroamination Reactions of Alkynes with ortho‐Substituted Anilines in Ball Mills: Synthesis of Benzannulated N‐Heterocycles by a Cascade Reaction
Authors: Weiße Maik , Zille Markus , Jacob Katharina , Schmidt Robert , Stolle Achim 
Published: March 2015

AbstractIt was demonstrated that ortho‐substituted anilines are prone to undergo hydroamination reactions with diethyl acetylenedicarboxylate in a planetary ball mill. A sequential coupling of the intermolecular hydroamination reaction with intramolecular ring closure was utilized for the syntheses of benzooxazines, quinoxalines, and benzothiazines from readily available building blocks, that is, electrophilic alkynes and anilines with OH, NH, or SH groups in the ortho position. For the heterocycle formation, it was shown that several stress conditions were able to initiate the reaction in the solid state. Processing in a ball mill seemed to be advantageous over comminution with mortar and pestle with respect to process control. In the latter case, significant postreaction modification occurred during solid‐state analysis. Cryogenic milling proved to have an adverse effect on the molecular transformation of the reagents.
A Ruthenium‐Based Biomimetic Hydrogen Cluster for Efficient Photocatalytic Hydrogen Generation from Formic Acid
Authors: Chang Chin‐Hao , Chen Mei‐Hua , Du Wan‐Shan , Gliniak Jacek , Lin Jia‐Hoa , Wu Hsin‐Hua , Chan Hsin‐Fang , Yu Jen‐Shiang K. , Wu Tung‐Kung 
Published: March 2015

AbstractA ruthenium‐based biomimetic hydrogen cluster, [Ru2(CO)6(μ‐SCH2CH2CH2S)] (1), has been synthesized and, in the presence of the P ligand tri(o‐tolyl)phosphine, demonstrated efficient photocatalytic hydrogen generation from formic acid decomposition. Turnover frequencies (TOFs) of 5500 h−1 and turnover numbers (TONs) over 24 700 were obtained with less than 50 ppm of the catalyst, thus representing the highest TOFs for ruthenium complexes as well as the best efficiency for photocatalytic hydrogen production from formic acid. Moreover, 1 showed high stability with no significant degradation of the photocatalyst observed after prolonged photoirradiation at 90 °C.
Competition between Nucleophilic Substitution of Halogen (SNAr) versus Substitution of Hydrogen (SNArH)—A Mass Spectrometry and Computational Study
Authors: Błaziak Kacper , Mąkosza Mieczysław , Danikiewicz Witold 
Published: March 2015

AbstractThe mechanism of intramolecular gas‐phase reactions of N‐(2‐X‐5‐nitrophenyl)‐N‐methylacetamide carbanions (X=H, F, Cl) has been studied using negative ion electrospray mass spectrometry ((−)ESI‐MS) technique and modelled computationally. It was proven that all three anions form cyclic σH adducts, which undergo elimination of water. In the case of X=F, formation of the σF adduct, leading to SNAr reaction, was a competing process. This is the first proof that also in the gas phase formation of σH adduct proceeds faster than σX adduct and only when X=F, rates of these two processes are comparable. The experimental results are in full agreement with quantum chemical calculations.
Designing Artificial 3D Helicates: Unprecedented Self‐Assembly of Homo‐octanuclear Tetrapods with Europium
Authors: Zebret Soumaila , Vögele Eliane , Klumpler Tomas , Hamacek Josef 
Published: March 2015

AbstractHerein, we report on the rational design, preparation and characterization of a novel homo‐octanuclear helicate, which results from a spatial extension of the central tetranuclear platform. The 3D supramolecular assembly is obtained by complexing europium(III) with a new hexatopic tripodal ligand. The isolated octanuclear helicate is fully characterized by different methods clearly evidencing the structure predicted with molecular modelling. The ligand preorganization plays a crucial role in a successful self‐assembly process and induces the formation of a well‐defined triple‐stranded helical structure. This prototypal octanuclear edifice accommodating functional lanthanides within a 3D scaffold offers attractive perspectives for further applications.
Covalent Attachment of Anderson‐Type Polyoxometalates to Single‐Walled Carbon Nanotubes Gives Enhanced Performance Electrodes for Lithium Ion Batteries
Authors: Ji Yuanchun , Hu Jun , Huang Lujiang , Chen Wei , Streb Carsten , Song Yu‐Fei 
Published: March 2015

AbstractSingle‐walled carbon nanotubes (SWNTs) covalently functionalized with redox‐active organo‐modified polyoxometalate (POM) clusters have been synthesized and employed as electrode materials in lithium ion batteries. The Anderson cluster [MnMo6O24]9− is functionalized with Tris (NH2C(CH2OH)3) moieties, giving the new organic–inorganic hybrid [N(nC4H9)4]3[MnMo6O18{(OCH2)3CNH2}2]. The compound is then covalently attached to carboxylic acid‐functionalized SWNTs by amide bond formation and the stability of this nanocomposite is confirmed by various spectroscopic methods. Electrochemical analyses show that the nanocomposite displays improved performance as an anode material in lithium ion batteries compared with the individual components, that is, SWNTs and/or Anderson clusters. High discharge capacities of up to 932 mAh g−1 at a current density of 0.5 mA cm−2 can be observed, together with high long‐term cycling stability and decreased electrochemical impedance. Chemisorption of the POM cluster on the SWNTs is shown to give better electrode performance than the purely physisorbed analogues.
Amplified somatosensory and visual cortical projections to a core auditory area, the anterior auditory field, following early‐ and late‐onset deafness
Authors: Wong Carmen , Chabot Nicole , Kok Melanie A. , Lomber Stephen G. 
Published: March 2015

AbstractCross‐modal reorganization following the loss of input from a sensory modality can recruit sensory‐deprived cortical areas to process information from the remaining senses. Specifically, in early‐deaf cats, the anterior auditory field (AAF) is unresponsive to auditory stimuli but can be activated by somatosensory and visual stimuli. Similarly, AAF neurons respond to tactile input in adult‐deafened animals. To examine anatomical changes that may underlie this functional adaptation following early or late deafness, afferent projections to AAF were examined in hearing cats, and cats with early‐ or adult‐onset deafness. Unilateral deposits of biotinylated dextran amine were made in AAF to retrogradely label cortical and thalamic afferents to AAF. In early‐deaf cats, ipsilateral neuronal labeling in visual and somatosensory cortices increased by 329% and 101%, respectively. The largest increases arose from the anterior ectosylvian visual area and the anterolateral lateral suprasylvian visual area, as well as somatosensory areas S2 and S4. Consequently, labeling in auditory areas was reduced by 36%. The age of deafness onset appeared to influence afferent connectivity, with less marked differences observed in late‐deaf cats. Profound changes to visual and somatosensory afferent connectivity following deafness may reflect corticocortical rewiring affording acoustically deprived AAF with cross‐modal functionality. J. Comp. Neurol. 523:1925–1947, 2015 © 2015 Wiley Periodicals, Inc.
Intermediate Electrostatic Field for the Generalized Elongation Method
Authors: Liu Kai , Korchowiec Jacek , Aoki Yuriko 
Published: March 2015

AbstractAn intermediate electrostatic field is introduced to improve the accuracy of fragment‐based quantum‐chemical computational methods by including long‐range polarizations of biomolecules. The point charge distribution of the intermediate field is generated by a charge sensitivity analysis that is parameterized for five different population analyses, namely, atoms‐in‐molecules, Hirshfeld, Mulliken, natural orbital, and Voronoi population analysis. Two model systems are chosen to demonstrate the performance of the generalized elongation method (ELG) combined with the intermediate electrostatic field. The calculations are performed for the STO‐3G, 6‐31G, and 6‐31G(d) basis sets and compared with reference Hartree–Fock calculations. It is shown that the error in the total energy is reduced by one order of magnitude, independently of the population analyses used. This demonstrates the importance of long‐range polarization in electronic‐structure calculations by fragmentation techniques.
Energy‐efficient power allocation for cognitive radio networks with minimal rate requirements
Authors: Sun Xun , Wang Shaowei 
Published: March 2015

SummaryBecause the energy consumption is growing rapidly, green radio, which lays emphasis on the energy efficiency (EE) in wireless networks, is becoming increasingly important. As potential paradigms for future wireless network design, cognitive radio (CR) is a promising technology to solve the spectrum shortage and inefficiency issues, while cooperative relay is capable of improving spectral efficiency by combating severe fading in wireless environment. In this paper, we investigate the energy‐efficient power allocation problem in orthogonal frequency division multiplexing (OFDM)‐based relaying CR networks. We develop a general framework to maximize the overall EE of the CR system, under the constraints of transmission power budget, traffic demands, and the interference constraints of the primary users. Our problem formulation is a nonconvex optimization task, and it is hard to obtain the optimal solution. We first convert our formulated problem into a convex optimization problem via its hypograph form, which can be solved by the barrier method. Then we further speed up the computation of Newton step during the barrier method, significantly reducing the complexity of the algorithm by exploiting its special structure. Numerical results validate that our method can exploit the overall EE of CR systems, while the algorithm converges efficiently and stably. Copyright © 2015 John Wiley & Sons, Ltd.
A comparative analysis of metacommunity types in the freshwater realm
Authors: Heino Jani , Soininen Janne , Alahuhta Janne , Lappalainen Jyrki , Virtanen Risto 
Published: March 2015

AbstractMost metacommunity studies have taken a direct mechanistic approach, aiming to model the effects of local and regional processes on local communities within a metacommunity. An alternative approach is to focus on emergent patterns at the metacommunity level through applying the elements of metacommunity structure (EMS; Oikos, 97, 2002, 237) analysis. The EMS approach has very rarely been applied in the context of a comparative analysis of metacommunity types of main microbial, plant, and animal groups. Furthermore, to our knowledge, no study has associated metacommunity types with their potential ecological correlates in the freshwater realm. We assembled data for 45 freshwater metacommunities, incorporating biologically highly disparate organismal groups (i.e., bacteria, algae, macrophytes, invertebrates, and fish). We first examined ecological correlates (e.g., matrix properties, beta diversity, and average characteristics of a metacommunity, including body size, trophic group, ecosystem type, life form, and dispersal mode) of the three elements of metacommunity structure (i.e., coherence, turnover, and boundary clumping). Second, based on those three elements, we determined which metacommunity types prevailed in freshwater systems and which ecological correlates best discriminated among the observed metacommunity types. We found that the three elements of metacommunity structure were not strongly related to the ecological correlates, except that turnover was positively related to beta diversity. We observed six metacommunity types. The most common were Clementsian and quasi‐nested metacommunity types, whereas Random, quasi‐Clementsian, Gleasonian, and quasi‐Gleasonian types were less common. These six metacommunity types were best discriminated by beta diversity and the first axis of metacommunity ecological traits, ranging from metacommunities of producer organisms occurring in streams to those of large predatory organisms occurring in lakes. Our results showed that focusing on the emergent properties of multiple metacommunities provides information additional to that obtained in studies examining variation in local community structure within a metacommunity.
Human metapneumovirus infection activates the TSLP pathway that drives excessive pulmonary inflammation and viral replication in mice
Authors: Lay Margarita K. , Céspedes Pablo F. , Palavecino Christian E. , León Miguel A. , Díaz Rodrigo A. , Salazar Francisco J. , Méndez Gonzalo P. , Bueno Susan M. , Kalergis Alexis M. 
Published: March 2015

Human metapneumovirus (hMPV) is a leading cause of acute respiratory tract infections in children and the elderly. The mechanism by which this virus triggers an inflammatory response still remains unknown. Here, we evaluated whether the thymic stromal lymphopoietin (TSLP) pathway contributes to lung inflammation upon hMPV infection. We found that hMPV infection promotes TSLP expression both in human airway epithelial cells and in the mouse lung. hMPV infection induced lung infiltration of OX40L+CD11b+ DCs. Mice lacking the TSLP receptor deficient mice (tslpr−/−) showed reduced lung inflammation and hMPV replication. These mice displayed a decreased number of neutrophils as well a reduction in levels of thymus and activation‐regulated chemokine/CCL17, IL‐5, IL‐13, and TNF‐α in the airways upon hMPV infection. Furthermore, a higher frequency of CD4+ and CD8+ T cells was found in tslpr−/− mice compared to WT mice, which could contribute to controlling viral spread. Depletion of neutrophils in WT and tslpr−/− mice decreased inflammation and hMPV replication. Remarkably, blockage of TSLP or OX40L with specific Abs reduced lung inflammation and viral replication following hMPV challenge in mice. Altogether, these results suggest that activation of the TSLP pathway is pivotal in the development of pulmonary pathology and pulmonary hMPV replication.
Electrochemical Investigation of Metal Oxide Conducting Electrodes for Direct Detection of Sulfide
Authors: Aziz Md. Abdul , Sohail Manzar , Oyama Munetaka , Mahfoz Wael 
Published: March 2015

AbstractThis study examined the performance of four conducting metal oxide electrodes for the direct electrochemical analysis of sulfide; the electrode materials studied were indium tin oxide (ITO), fluorine doped tin oxide (FTO), aluminum doped zinc oxide (AZO) and gallium doped zinc oxide (GZO). Cyclic voltammetry (CV) results obtained using the ITO, AZO, GZO and FTO electrodes showed direct electrooxidation peak potential of sulfide at 381, 507, 400, and 850 mV vs. Ag/AgCl, respectively; however, the less positive oxidation potential and high catalytic current response of the ITO electrode made it the electrode of choice for the direct oxidation of sulfide. The effects of different electrolytes and buffer solutions on the CV responses were also evaluated. A linear concentration range up to 350 µM and a detection limit of 8.0 µM were achieved. CV response was highly reproducible, remaining unaffected even after 50 measurements. The sensor was found to have good selectivity, with no interference from sulfite, sulfate or chloride ions. The present findings demonstrate that the bare ITO electrode can be used as the basis of an inexpensive, sensitive, selective and robust sulfide sensor.
Finite‐element analysis of laminated rubber bearing of building frame under seismic excitation
Authors: Ohsaki Makoto , Miyamura Tomoshi , Kohiyama Masayuki , Yamashita Takuzo , Yamamoto Masashi , Nakamura Naohiro 
Published: March 2015

SummaryFinite element analysis is carried out for a building frame supported by laminated rubber bearings to simultaneously investigate global displacement and local stress responses under seismic excitation. The frame members and the rubber bearings are discretized into hexahedral solid elements with more than 3 million degrees of freedom. The material property of rubber is represented by the Ogden model, and the frame is assumed to remain in elastic range. It is shown that the time histories of non‐uniform stress distribution and rocking behavior of the rubber bearings under a frame subjected to seismic excitation can be successfully evaluated, and detailed responses of base and frame can be evaluated through large‐scale finite element analysis. Copyright © 2015 John Wiley & Sons, Ltd.
Maximal flow‐level stability of best‐rate schedulers in heterogeneous wireless systems
Authors: Jacko P. , Morozov E. , Potakhina L. , Verloop I. M. 
Published: March 2015

AbstractWe investigate flow‐level stability of schedulers in parallel‐service wireless systems, which is important for maximizing the base station's capacity to serve the heterogeneous flows that are within the base station's power range. We model such a system as a multi‐class queueing system with multiple preemptive servers, in which flows of different classes randomly arrive and depart once their flow is completed. The channel condition of a flow varies randomly over time because of fading and mobility. The evolution of the channel condition is assumed to be Markovian and class dependent. We focus on a general family of the best‐rate schedulers that, whenever possible, serve flows that are in the channel condition corresponding to the highest achievable class‐dependent transmission rate (i.e. the best rate). We prove under mild assumptions that any best‐rate scheduler achieves maximal stability, that is, stabilizes the system whenever possible, in all systems with generally distributed class‐dependent arrivals and flow sizes. Copyright © 2015 John Wiley & Sons, Ltd.
Has the Swap Influenced Aid Flows in the Health Sector?
Authors: Sweeney Rohan , Mortimer Duncan 
Published: March 2015

AbstractThe sector wide approach (SWAp) emerged during the 1990s as a mechanism for managing aid from the multiplicity of development partners that operate in the recipient country's health, education or agricultural sectors. Health SWAps aim to give increased control to recipient governments, allowing greater domestic influence over how health aid is allocated and facilitating allocative efficiency gains. This paper assesses whether health SWAps have increased recipient control of health aid via increased general sector‐support and have facilitated (re)allocations of health aid across disease areas.Using a uniquely compiled panel data set of countries receiving development assistance for health over the period 1990–2010, we employ fixed effects and dynamic panel models to assess the impact of introducing a health SWAp on levels of general sector‐support for health and allocations of health‐sector aid across key funding silos (including HIV, ‘maternal and child health’ and ‘sector‐support’). Our results suggest that health SWAps have influenced health‐sector aid flows in a manner consistent with increased recipient control and improvements in allocative efficiency. Copyright © 2015 John Wiley & Sons, Ltd.
Biocompatibility of calcium phosphate bone cement with optimized mechanical properties
Authors: Palmer Iwan , Nelson John , Schatton Wolfgang , Dunne Nicholas J. , Buchanan Fraser J. , Clarke Susan A. 
Published: March 2015

AbstractThe broad aim of this work was to investigate and optimize the properties of calcium phosphate bone cements (CPCs) for use in vertebroplasty to achieve effective primary fixation of spinal fractures. The incorporation of collagen, both bovine and from a marine sponge (Chondrosia reniformis), into a CPC was investigated. The biological properties of the CPC and collagen–CPC composites were assessed in vitro through the use of human bone marrow stromal cells. Cytotoxicity, proliferation, and osteoblastic differentiation were evaluated using lactate dehydrogenase, PicoGreen, and alkaline phosphatase activity assays, respectively. The addition of both types of collagen resulted in an increase in cytotoxicity, albeit not to a clinically relevant level. Cellular proliferation after 1, 7, and 14 days was unchanged. The osteogenic potential of the CPC was reduced through the addition of bovine collagen but remained unchanged in the case of the marine collagen. These findings, coupled with previous work showing that incorporation of marine collagen in this way can improve the physical properties of CPCs, suggest that such a composite may offer an alternative to CPCs in applications where low setting times and higher mechanical stability are important. © 2015 The Authors. Journal of Biomedical Materials Research Part B: Applied Biomaterials Published by Wiley Periodicals, Inc. 104B:308–315, 2015.