bluuebunny/crossref_metadata_2025_split huggingface dataset:
Silica‐Supported Molybdenum Alkylidyne N‐Heterocyclic Carbene Catalysts: Relevance of Site Isolation to Catalytic Performance
Authors: Hauser Philipp M. , Hunger Michael , Buchmeiser Michael R. 
Published: January 2018

AbstractThe immobilization of the molybdenum alkylidyne complex [(p‐OMe‐C6H4C≡)Mo(OCMe(CF3)2)3⋅DME] (DME=1,2‐dimethoxyethane) on silica using a silica‐supported N‐heterocyclic carbene (NHC), that is, 1,3‐di(isopropyl)imidazol‐2‐ylidene, is reported. Two different types of silica, that is, silica 60 and partially dehydroxylated silica 60 obtained via heating to 650 °C (SiO2‐650) were used. In both cases, excess silanol groups were end‐capped with trimethylsilyl chloride. Immobilization of both the NHC precursor and the metal alkylidyne was followed by 19F magic angle spinning (MAS) and 13C cross‐polarization magic angle spinning (CPMAS) NMR and inductively‐coupled optical emission spectroscopy (ICP–OES). The metal alkylidyne supported on both types of silica was active in alkyne metathesis and showed activity for a series of functional 2‐alkynes. Most importantly, the metal alkylidyne supported on SiO2‐650 displayed a substantially higher alkyne metathesis activity than the homogeneous analog or the one supported on regular silica, which is attributed to a site isolation effect and, as a result, reduced bimolecular decomposition.
Coupling of Methane to Ethane, Ethylene, and Aromatics over Nickel on Ceria–Zirconia at Low Temperatures
Authors: Okolie Chukwuemeka , Lyu Yimeng , Kovarik Libor , Stavitski Eli , Sievers Carsten 
Published: January 2018

AbstractMethane is converted over nickel on ceria zirconia (Ni/CZ) into ethane, aromatics, and hydrogen at steady state up to the thermodynamic limit at temperatures of 350 to 500 °C. At 450 and 500 °C, traces of ethylene are also produced. Ni/NiO particles activate methane and couple the resulting surface species to hydrocarbon products. Large Ni particles are responsible for the formation of carbonaceous deposits. Furthermore, aromatics are formed on these sites. Smaller Ni/NiO particles are responsible for the formation of ethane and ethylene and appear to provide sustained activity. It is suggested that these Ni sites are too small to assemble aromatic deposits, and hence they remain active throughout the reaction.
POM & MOF‐based Electrocatalysts for Energy‐related Reactions
Authors: Freire Cristina , Fernandes Diana M. , Nunes Marta , Abdelkader Victor K. 
Published: January 2018

AbstractElectrocatalysis plays a central role in clean energy conversion, enabling a number of sustainable processes for future technologies and the development of highly efficient and cost‐effective materials is one of the current major challenges. This results from the current global energy crisis, reflected in the depletion of fossil fuels and growth of the environmental pollution, which has stimulated the development of novel renewable energy storage and conversion technologies. Currently, several electrocatalysts have been proposed and among them are the polyoxometalates (POMs), the metal‐organic frameworks (MOFs) and their based composites.
Mesoporous Carbon Nitride Supported Pd and Pd‐Ni Nanoparticles as Highly Efficient Catalyst for Catalytic Hydrolysis of NH3BH3
Authors: Wang Wei , Lu Zhang‐Hui , Luo Yan , Zou Aihua , Yao Qilu , Chen Xiangshu 
Published: January 2018

AbstractHighly dispersed Pd and PdNi nanoparticles (NPs) have been successfully immobilized on mesoporous carbon nitride (MCN) through a facile co‐reduction approach. The resulting Pd/MCN catalyst shows excellent catalytic performance for hydrogen release from an ammonia borane (AB) aqueous solution with a turnover frequency (TOF) value of 125 mol H2 mol metal−1 min−1 at room temperature, which is among the highest values for monometallic Pd‐based catalysts reported to date. The catalytic performance of the Pd NPs can be further enhanced by alloying with Ni or Co atoms. Among all the synthesized PdxNi100−x/MCN nanocomposites (NCs) with different Ni/Pd ratios, the Pd74Ni26/MCN catalyst exhibits the best catalytic performance with a TOF of 246.8 mol H2 mol metal−1 min−1. The high activity of Pd/MCN and Pd74Ni26/MCN are largely dependent on the features of the ultrafine metallic NPs immobilized by MCN, the interfacial interaction between the MCN matrix and metallic NPs, and the accessible open porous structure for mass transfer.
Heterogenized C‐Scorpionate Iron(II) Complex on Nanostructured Carbon Materials as Recyclable Catalysts for Microwave‐Assisted Oxidation Reactions
Authors: Ribeiro Ana P. C. , Martins Luísa M. D. R. S. , Carabineiro Sónia A. C. , Buijnsters Josephus G. , Figueiredo José L. , Pombeiro Armando J. L. 
Published: January 2018

AbstractThe C‐scorpionate iron(II) complex [FeCl2(Tpm)] [Tpm=κ3‐HC(C3H3N2)3] (1) was immobilized on five different nanostructured carbon materials (nanodiamonds, graphene nanoplatelets, graphene oxide, reduced graphene oxide, and nanohorns) to produce active, selective, and recyclable catalysts for alkane and alcohol oxidations. The heterogenized systems (including the first ever reported complexes supported on carbon nanohorns) exhibited good activity concomitant with rather high selectivity to the formation of ketone alcohol (KA) oil (cyclohexanol and cyclohexanone mixture, yields up to 29 %) from microwave‐assisted oxidation of cyclohexane, and allowed their easy recovery and reuse, at least for five consecutive cycles maintaining 90.3 % of the initial activity. Moreover, the functionalized nanodiamond supports (used for the first time as supports for iron complexes) were also able to effectively (yields up to 97 %) catalyze the microwave‐induced oxidation of 1‐ and 2‐phenylethanol to acetophenone and 2‐phenylacetaldehyde, respectively, and could be reused for seven consecutive cycles without losing catalytic activity.
Gold Nanoparticle/Multi‐walled Carbon Nanotube Hybrid as a Stable Catalyst for the Oxygen Reduction Reaction
Authors: Xiang Li , Luo Zhihong , Hu Chengliang , Bian Zhicheng , Lu Jianwei , Cao Yuan‐Cheng , Luo Kun 
Published: January 2018

AbstractA gold nanoparticle/multi‐walled carbon nanotube (Au/MWNTs) hybrid was prepared following the scalable one‐pot reduction of chloroauric acid with tetrakis(hydroxymethyl)chloride in the presence of MWNTs. TEM, XRD, FTIR, XPS, and thermogravimetric analyses indicate that gold nanoparticles (Au NPs, d≈2.9 nm) protected with the tris(hydroxymethyl)oxide (THPO) ligand were deposited on the MWNTs, where no Oswald ripening was observed for the Au NPs after 3000 voltammetric cycling. The Au/MWNTs hybrid with THPO ligand exhibits an impressive catalytic activity toward the oxygen reduction reaction (ORR), following a direct four‐electron mechanism in alkaline solution, and it also manifests excellent long‐term cycling durability and tolerance to the possible crossover methanol. This demonstrates prospective for the hybrid to serve as a stable ORR catalyst for direct methanol fuel cells.
Rates of Chemical Reactions Embedded in a Metabolic Network by Dissolution Dynamic Nuclear Polarisation NMR
Authors: Sadet Aude , Weber Emmanuelle M. M. , Jhajharia Aditya , Kurzbach Dennis , Bodenhausen Geoffrey , Miclet Emeric , Abergel Daniel 
Published: January 2018

AbstractThe isomerisation of 6‐phosphogluconolactones and their hydrolyses into 6‐phosphogluconic acid form a non enzymatic side cycle of the pentose‐phosphate pathway (PPP) in cells. Dissolution dynamic nuclear polarisation can be used for determining the kinetic rates of the involved transformations in real time. It is found that the hydrolysis of both lactones is significantly slower than the isomerisation process, thereby shedding new light onto this subtle chemical process.
Sigma‐ versus Pi‐Dimerization Modes of Triangulene
Authors: Mou Zhongyu , Kertesz Miklos 
Published: January 2018

AbstractWe show that the diradicaloid triangulene, a graphene nano‐flake molecule, can aggregate in a variety of dimerization modes. We found by density functional theory modeling a number of triangulene dimers including six doubly bonded σ‐dimers in addition to the previously reported six pancake bonded π‐dimer isomers. The σ‐dimers display a wide range of stabilities: the interaction energy of the most stable σ‐dimer is −25.17 kcal mol−1. Besides the doubly bonded σ‐dimers with closed shell ground states, we also found an open‐shell singly σ‐bonded diradicaloid dimer. We found an interesting isomerization route between a doubly bonded σ‐dimer, a singly bonded σ‐dimer with a low‐lying triplet state and two π‐bonded dimers with low‐lying quintet states. Derivatives of triangulene, trioxo‐triangulenes (TOTs) have been previously characterized experimentally. Here, we show the reasons why so far only the π‐dimer but not the σ‐dimer was experimentally observed for all TOTs.
Secondary Metabolites from Escovopsis weberi and Their Role in Attacking the Garden Fungus of Leaf‐Cutting Ants
Authors: Dhodary Basanta , Schilg Michele , Wirth Rainer , Spiteller Dieter 
Published: January 2018

AbstractThe specialized, fungal pathogen Escovopsis weberi threatens the mutualistic symbiosis between leaf‐cutting ants and their garden fungus (Leucoagaricus gongylophorus). Because E. weberi can overwhelm L. gongylophorus without direct contact, it was suspected to secrete toxins. Using NMR and mass spectrometry, we identified several secondary metabolites produced by E. weberi. E. weberi produces five shearinine‐type indole triterpenoids including two novel derivatives, shearinine L and shearinine M, as well as the polyketides, emodin and cycloarthropsone. Cycloarthropsone and emodin strongly inhibited the growth of the garden fungus L. gongylophorous at 0.8 and 0.7 μmol, respectively. Emodin was also active against Streptomyces microbial symbionts (0.3 μmol) of leaf‐cutting ants. Shearinine L instead did not affect the growth of L. gongylophorus in agar diffusion assays. However, in dual choice behavioral assays Acromyrmex octospinosus ants clearly avoided substrate treated with shearinine L for the garden fungus after a 2 d learning period, indicating that the ants quickly learn to avoid shearinine L.
Comparison of Commercial and Reacetylated Chitosan with Regard to Their Flocculation Quality
Authors: Haufe Sandra , Bohrisch Jörg , Bratskaya Svetlana Y. , Schwarz Simona 
Published: January 2018

AbstractChitosan steht seit einigen Jahren im Fokus biologisch orientierter Forschung sowohl in der Modifizierung als auch in der Anwendung. Es hat eine Vielzahl von Vorteilen gegenüber synthetischen Produkten, es ist z. B. nicht toxisch. In dieser Arbeit wurden die Chitosane reacetyliert und charakterisiert. Reacetylierte Chitosane lösen sich ohne Zusätze in Wasser und zeigen gute Flockungseigenschaften. Die Flockung von reacetylierten und kommerziellen Chitosanen wurde verglichen. Molmasse, pH‐Wert und der Salzgehalt im System nehmen großen Einfluss auf die Lage und Breite der Flockungsfenster.
Comprendre les pratiques des experts pour être en mesure de contrôler leur activité – l’exemple du trading
Authors: Jardat Rémi , Méric Jérôme , Sfez Flora 
Published: January 2018

AbstractExperts are important actors of organizational control. Nevertheless, experience suggests that they must be controlled as well. This is particularly the case for traders in financial institutions. We first identify the limits of traditional control patterns when the managing the activities of experts is at stake. Hyperspecialization, which is the ability to act within different logics and multiple time horizons, suggests that multidimensional representations of these activities be adopted and made explicit, which has the potential to prevent such activities from turning problematic. By examining bank risks and conducting additional interviews with actors from bank trading services, we recommend that multiple components of complexity be preserved when dealing with expert‐related operational risks, instead of reducing this complexity to a single concept. Such an approach implies to turn back expertise against itself. Copyright © 2017 ASAC. Published by John Wiley & Sons, Ltd.
Association between clinical factors and self‐underestimation of cardiovascular risk in subjects submitted to a routine health evaluation
Authors: Helou Thais N. , Santos Raul D. , Laurinavicius Antonio G. , Bittencourt Marcio Sommer , Pesaro Antonio E.P. , Franco Fabio G.M. , Conceição Raquel D.O. , Carvalho José A.M. , Silva Fernando M.F. , Wajngarten Mauricio , Katz Marcelo 
Published: January 2018

BackgroundThe perception of cardiovascular (CV) risk is essential for adoption of healthy behaviors. However, subjects underestimate their own risk.HypothesisClinical characteristics might be associated with self‐underestimation of CV risk.MethodsThis is a retrospective, cross‐sectional study of individuals submitted to routine health evaluation between 2006 and 2012, with calculated lifetime risk score (LRS) indicating intermediate or high risk for CV disease (CVD). Self‐perception of risk was compared with LRS. Logistic regression analysis was performed to test the association between clinical characteristics and subjective underestimation of CV risk.ResultsData from 5863 subjects (age 49.4 ± 7.1 years; 19.9% female) were collected for analysis. The LRS indicated an intermediate risk for CVD in 45.7% and a high risk in 54.3% of individuals. The self‐perception of CV risk was underestimated compared with the LRS in 4918 (83.9%) subjects. In the adjusted logistic regression model, age (odds ratio [OR]: 1.28, 95% confidence interval [CI]: 1.10‐1.47 per 10 years, P = 0.001), smoking (OR: 1.99, 95% CI: 1.40‐2.83, P < 0.001), dyslipidemia (OR: 1.21, 95% CI: 1.01‐1.46, P = 0.045), physical activity (OR: 1.66, 95% CI: 1.36‐2.02, P < 0.001), and use of antihypertensive (OR: 1.49, 95% CI: 1.15‐1.92, P = 0.002) and lipid‐lowering medications (OR: 2.13, 95% CI: 1.56‐2.91, P < 0.001) were associated with higher chance of risk underestimation, whereas higher body mass index (OR: 0.92, 95% CI: 0.90‐0.94, P < 0.001), depressive symptoms (OR: 0.46, 95% CI: 0.37‐0.57, P < 0.001), and stress (OR: 0.41, 95% CI: 0.33‐0.50, P < 0.001) decreased the chance.ConclusionsAmong individuals submitted to routine medical evaluation, aging, smoking, dyslipidemia, physical activity, and use of antihypertensive and lipid‐lowering medications were associated with higher chance of CV risk underestimation. Subjects with these characteristics may benefit from a more careful risk orientation.
Variation in practice patterns and outcomes across United Network for Organ Sharing allocation regions
Authors: Srinivasan Dushyanth , Vaccaro Benjamin , Rao Pooja , Ghosh Rohit , Warier Prashant , Ahmad Tariq , Desai Nihar 
Published: January 2018

BackgroundThe number of heart transplants performed is limited by organ availability and is managed by the United Network for Organ Sharing (UNOS). Efforts are underway to make organ disbursement more equitable as demand increases.HypothesisSignificant variation exists in contemporary patterns of care, wait times, and outcomes among patients undergoing heart transplantation across UNOS regions.MethodsWe identified adult patients undergoing first, single‐organ heart transplantation between January 2006 and December 2014 in the UNOS dataset and compared sociodemographic and clinical profiles, wait times, use of mechanical circulatory support (MCS), status at time of transplantation, and 1‐year survival across UNOS regions.ResultsWe analyzed 17 096 patients undergoing heart transplantation. There were no differences in age, sex, renal function, and peripheral vascular resistance across regions; however, there was 3‐fold variation in median wait time (range, 48–166 days) across UNOS regions. Proportion of patients undergoing transplantation with status 1A ranged from 36% to 79% across regions (P < 0.01), and percentage of patients hospitalized at time of transplantation varied from 41% to 98%. There was also marked variation in MCS and inotrope utilization (28%–57% and 25%–58%, respectively; P < 0.001). Durable ventricular assist device implantation varied from 20% to 44% (P < 0.001), and intra‐aortic balloon pump utilization ranged from 4% to 18%.ConclusionsMarked differences exist in patterns of care across UNOS regions that generally trend with differences in waitlist time. Novel policy initiatives are required to address disparities in access to allografts and ensure equitable and efficient allocation of organs.
Comprehensive analysis of area‐specific and time‐dependent changes in gene expression in the motor cortex of macaque monkeys during recovery from spinal cord injury
Authors: Higo Noriyuki , Sato Akira , Yamamoto Tatsuya , Oishi Takao , Nishimura Yukio , Murata Yumi , Onoe Hirotaka , Isa Tadashi , Kojima Toshio 
Published: January 2018

AbstractThe present study aimed to assess the molecular bases of cortical compensatory mechanisms following spinal cord injury in primates. To accomplish this, comprehensive changes in gene expression were investigated in the bilateral primary motor cortex (M1), dorsal premotor cortex (PMd), and ventral premotor cortex (PMv) after a unilateral lesion of the lateral corticospinal tract (l‐CST). At 2 weeks after the lesion, a large number of genes exhibited altered expression levels in the contralesional M1, which is directly linked to the lesioned l‐CST. Gene ontology and network analyses indicated that these changes in gene expression are involved in the atrophy and plasticity changes observed in neurons. Orchestrated gene expression changes were present when behavioral recovery was attained 3 months after the lesion, particularly among the bilateral premotor areas, and a large number of these genes are involved in plasticity. Moreover, several genes abundantly expressed in M1 of intact monkeys were upregulated in both the PMd and PMv after the l‐CST lesion. These area‐specific and time‐dependent changes in gene expression may underlie the molecular mechanisms of functional recovery following a lesion of the l‐CST.
An efficient iterative graph data processing framework based on bulk synchronous parallel model
Authors: Liu Chao , Zeng Deze , Yao Hong , Yan Xuesong , Yu Linchen , Fu Zhangjie 
Published: January 2018

SummaryGraph data processing has been widely applied in a variety of domains such as industry, science, social network, and so on. It therefore has stimulated many efforts devoted to this area. To embrace the fast development trend of big graph data, graph data processing based on Pregel‐like systems has been regarded as one of the most promising ways and has widely attracted the attention of researchers. However, it still remains in its early stage and there still exist many challenges. In Pregel, the superstep synchronization is time consuming as the graph data iteration operation requires multiple synchronizations. Furthermore, the graph data partition strategy adopted by Pregel fails to support load balancing, therefore causing the increase of network I/O overhead as the scale of graph data grows. To address these issues, this paper presents an efficient computational framework for graph data processing based on the bulk synchronous parallel model. The global synchronization control mechanism is improved by determining the start time of the next round of superstep through counting the number of global message files. Furthermore, an improved graph data partition mechanism based on a balanced hash method is proposed to reduce the communication overhead between different partitions of sub‐graph computational tasks. We also re‐design the PageRank algorithm to verify the effectiveness of the proposed framework. Experimental results on different real‐world datasets verify the efficiency of our proposed framework as it outperforms Giraph (an open source Pregel‐like system) by 58%−69%, and achieves 10×−17× performance improvement over Hadoop.
On the Action of General Anesthetics on Cellular Function: Barbiturate Alters the Exocytosis of Catecholamines in a Model Cell System
Authors: Ye Daixin , Ewing Andrew 
Published: January 2018

AbstractGeneral anesthetics are essential in many areas, however, the cellular mechanisms of anesthetic‐induced amnesia and unconsciousness are incompletely understood. Exocytosis is the main mechanism of signal transduction and neuronal communication through the release of chemical transmitters from vesicles to the extracellular environment. Here, we use disk electrodes placed on top of PC12 cells to show that treatment with barbiturate induces fewer molecules released during exocytosis and changes the event dynamics perhaps by inducing a less stable fusion pore that is prone to close faster during partial exocytosis. Larger events are essentially abolished. However, use of intracellular vesicle impact electrochemical cytometry using a nano‐tip electrode inserted into a cell shows that the distribution of vesicle transmitter content does not change after barbiturate treatment. This indicates that barbiturate selectively alters the pore size of larger events or perhaps differentially between types of vesicles. Alteration of exocytosis in this manner could be linked to the effects of general anesthetics on memory loss.
Atmospheric Dry Hydrogen Plasma Reduction of Inkjet‐Printed Flexible Graphene Oxide Electrodes
Authors: Homola Tomáš , Pospíšil Jan , Krumpolec Richard , Souček Pavel , Dzik Petr , Weiter Martin , Černák Mirko 
Published: January 2018

AbstractThis study concerns a low‐temperature method for dry hydrogen plasma reduction of inkjet‐printed flexible graphene oxide (GO) electrodes, an approach compatible with processes envisaged for the manufacture of flexible electronics. The processing of GO to reduced graphene oxide (rGO) was performed in 1–64 s, and sp2/sp2+sp3 carbon concentration increased from approximately 20 % to 90 %. Since the plasma reduction was associated with an etching effect, the optimal reduction time occurred between 8 and 16 s. The surface showed good mechanical stability when deposited on polyethylene terephthalate flexible foils and significantly lower sheet resistance after plasma reduction. This method for dry plasma reduction could be important for large‐area hydrogenation and reduction of GO flexible surfaces, with present and potential applications in a wide variety of emerging technologies.
Improvement of diagnostic performance of pathologists by reducing the number of pathologists responsible for thyroid fine needle aspiration cytology: An institutional experience
Authors: Seok Jae Yeon , An Jungsuk , Cho Hyun Yee 
Published: January 2018

BackgroundVarious efforts have been made to improve the diagnostic accuracy of thyroid fine needle aspiration (FNA) cytology. We changed the diagnostic system by reducing the number of pathologists responsible for the thyroid FNA cytology in the routine work, and analyzed the effect on the pathologist's diagnostic performance.MethodsSince March 1, 2015, 3 pathologists have been responsible for diagnostic thyroid FNA, previously undertaken by 9 equally. We compared the prechange period (three months, 319 nodules) and the postchange period (12 months, 1194 nodules).ResultsThe turnaround time was shortened from 1.4 ± 0.7 days to 0.9 ± 0.5 days (P < .001). The utilization rate of the Bethesda system for Reporting Thyroid Cytopathology (TBSRTC) increased from 92.5% to 99.8%. Diagnostic rates of categories that are confirmative [II (benign) and VI (malignant)] increased, while the inadequate (I) or indeterminate (III) categories decreased. With category IV (follicular neoplasm), a challenging category in our country, an elevated malignancy rate was found at follow‐up. Overall, the diagnostic performance was improved in terms of sensitivity (from 98.5% to 99.2%) and specificity (from 94.4% to 98.4%), with reduced false‐negative rates (from 1.5% to 0.8%) and false‐positive rates (from 2.9% to 1.1%). The area under the receiver operating characteristic curve increased from 0.861 to 0.958.ConclusionReducing the number of pathologists responsible for diagnostic thyroid FNA cytology resulted in a higher utilization rate of TBSRTC, and more rapid and accurate diagnosis.