bluuebunny/crossref_metadata_2025_split huggingface dataset:
Carbon Nanotube Growth on Nanozirconia under Strong Cathodic Polarization in Steam and Carbon Dioxide
Authors: Tao Youkun , Ebbesen Sune D. , Zhang Wei , Mogensen Mogens B. 
Published: February 2014

AbstractGrowth of carbon nanotubes (CNTs) catalyzed by zirconia nanoparticles was observed in the Ni–yttria doped zirconia (YSZ) composite cathode of a solid oxide electrolysis cell (SOEC) at approximately 875 °C during co‐electrolysis of CO2 and H2O to produce CO and H2. CNT was observed to grow under large cathodic polarizations specifically at the first 1 to 2 μm Ni–YSZ active cathode layer next to the YSZ electrolyte. High resolution transmission electron microscopy (HRTEM) shows that the CNTs are multi‐walled with diameters of approximately 20 nm and the catalyst particles have diameters in the range of 5 to 25 nm. The results of HRTEM and energy dispersive X‐ray spectroscopy (EDS) analysis confirm that the catalyst particles attached to the CNT are cubic zirconia. Most of the zirconia particles are located at one end of the CNTs, but particles embedded in the walls or inside the CNTs are also observed. Apart from the CNTs, graphitic layers covering zirconia nanoparticles are also widely observed. This work describes nano‐zirconia acting as a catalyst for the growth of CNT during electrochemical conversion of CO2 and H2O in a Ni‐YSZ cermet under strong cathodic polarization. An electrocatalytic mechanism is proposed for the CNT growth in SOECs. These findings provide further understanding not only on the mechanism of the catalytic growth of CNTs, but also on the local electrochemical properties of a highly polarized Ni–YSZ cathode at the micro and nano level.
Visible‐Light‐Induced Selective Photocatalytic Oxidation of Benzylamine into Imine over Supported Ag/AgI Photocatalysts
Authors: Zheng Zhanfeng , Chen Chao , Bo Arixin , Zavahir Fathima Sifani , Waclawik Eric R. , Zhao Jian , Yang Dongjiang , Zhu Huaiyong 
Published: February 2014

AbstractTitanate nanotubes (TNT) supported AgI nanoparticles were prepared by a two‐step method: the deposition of Ag2O on titanate nanotubes from AgNO3 solution and the subsequent I‐adsorption process from NaI solution. It is found that the supported AgI samples exhibited excellent photoactivity for the selective oxidation of benzylamine to the corresponding imine under visible light illumination and the photocatalyst can be used for many times without apparent activity loss. X‐ray diffraction studies, transmission electron microscopy, diffuse reflectance UV‐Vis spectroscopy and nitrogen adsorption measurements were used for the characterization of the as‐prepared and recycled AgI samples. It is found that under visible light irradiation, AgI partially decomposed to produce Ag/AgI nanostructure and thus stabilized. The photoactivity of supported Ag/AgI for the selective oxidation of benzylamine was studied in terms of the light intensity, wavelength, temperature and substituent. It is proposed that the formation of plasmonic Ag nanoparticles should be responsible for the high activity and selectivity.
Aqueous Sodium‐Ion Battery using a Na3V2(PO4)3 Electrode
Authors: Song Weixin , Ji Xiaobo , Zhu Yirong , Zhu Hanjun , Li Fangqian , Chen Jun , Lu Fang , Yao Yinpeng , Banks Craig. E. 
Published: February 2014

AbstractThe NASICON‐type Na3V2(PO4)3 (NVP) cathode material is investigated in an aqueous sodium‐ion battery, which is explored by using a three‐electrode system. The battery behaviors and capacitive properties of this electrode system are critically investigated by using 1 m Li2SO4, Na2SO4, and K2SO4 electrolytes, with an optimal performance found to arise in Na+‐based electrolyte, which exhibits a capacitance of 209 Fg−1 at 8.5 C as well as enhanced ion diffusion. Larger, hydrated Li+ is less able to diffuse into the network of NVP, and the low conductivity and mobility leads to near noncapacitive behavior. In the case of K+‐based electrolyte, NVP presents asymmetric cyclic voltammograms, owing to weak solvation and the high conductivity of K+, making the ions more easily able to form electric double‐layer capacitance on the surface or pores of NVP, rather than insert into the network. The equivalent circuit based on electrochemical impedance spectroscopy result is analyzed to account for the electrochemical insertion behavior of Na+ into NVP, involving ion transfer in electrolyte solution, ion diffusion from the electrolyte to the electrode surface, as well as charge transfer and ion diffusion in the electrode solid.
Dispersion and Orientation of Zeolite ZSM‐5 Crystallites within a Fluid Catalytic Cracking Catalyst Particle
Authors: Sprung Christoph , Weckhuysen Bert M. 
Published: February 2014

AbstractConfocal fluorescence microscopy was employed to selectively visualize the dispersion and orientation of zeolite ZSM‐5 domains inside a single industrially applied fluid catalytic cracking (FCC) catalyst particle. Large ZSM‐5 crystals served as a model system together with the acid‐catalyzed fluorostyrene oligomerization reaction to study the interaction of plane‐polarized light with these anisotropic zeolite crystals. The distinction between zeolite and binder material, such as alumina, silica, and clay, within an individual FCC particle was achieved by utilizing the anisotropic nature of emitted fluorescence light arising from the entrapped fluorostyrene‐derived carbocations inside the zeolite channels. This characterization approach provides a non‐invasive way for post‐synthesis characterization of an individual FCC catalyst particle in which the size, distribution, orientation, and amount of zeolite ZSM‐5 aggregates can be determined. It was found that the amount of detected fluorescence light originating from the stained ZSM‐5 aggregates corresponds to about 15 wt %. Furthermore, a statistical analysis of the emitted fluorescence light indicated that a large number of the ZSM‐5 domains appeared in small sizes of about 0.015–0.25 μm2, representing single zeolite crystallites or small aggregates thereof. This observation illustrated a fairly high degree of zeolite dispersion within the FCC binder material. However, the highest amount of crystalline material was aggregated into larger domains (ca. 1–5 μm2) with more or less similarly oriented zeolite crystallites. It is clear that this visualization approach may serve as a post‐synthesis quality control on the dispersion of zeolite ZSM‐5 crystallites within FCC particles.
Reaction of Alkynes and Azides: Not Triazoles Through Copper–Acetylides but Oxazoles Through Copper–Nitrene Intermediates
Authors: Haldón Estela , Besora Maria , Cano Israel , Cambeiro Xacobe C. , Pericàs Miquel A. , Maseras Feliu , Nicasio M. Carmen , Pérez Pedro J. 
Published: February 2014

AbstractWell‐defined copper(I) complexes of composition [Tpm*,BrCu(NCMe)]BF4 (Tpm*,Br=tris(3,5‐dimethyl‐4‐bromo‐pyrazolyl)methane) or [Tpa*Cu]PF6 (Tpa*=tris(3,5‐dimethyl‐pyrazolylmethyl)amine) catalyze the formation of 2,5‐disubstituted oxazoles from carbonyl azides and terminal alkynes in a direct manner. This process represents a novel procedure for the synthesis of this valuable heterocycle from readily available starting materials, leading exclusively to the 2,5‐isomer, attesting to a completely regioselective transformation. Experimental evidence and computational studies have allowed the proposal of a reaction mechanism based on the initial formation of a copper–acyl nitrene species, in contrast to the well‐known mechanism for the copper‐catalyzed alkyne and azide cycloaddition reactions (CuAAC) that is triggered by the formation of a copper–acetylide complex.
New Synthetic Routes towards Soluble and Dissymmetric Triphenodioxazine Dyes Designed for Dye‐Sensitized Solar Cells
Authors: Nicolas Yohann , Allama Fouzia , Lepeltier Marc , Massin Julien , Castet Frédéric , Ducasse Laurent , Hirsch Lionel , Boubegtiten Zahia , Jonusauskas Gediminas , Olivier Céline , Toupance Thierry 
Published: February 2014

AbstractNew π‐conjugated structures are constantly the subject of research in dyes and pigments industry and electronic organic field. In this context, the triphenodioxazine (TPDO) core has often been used as efficient photostable pigments and once integrated in air stable n‐type organic field‐effect transistor (OFET). However, little attention has been paid to the TPDO core as soluble materials for optoelectronic devices, possibly due to the harsh synthetic conditions and the insolubility of many compounds. To benefit from the photostability of TPDO in dye‐sensitized solar cells (DSCs), an original synthetic pathway has been established to provide soluble and dissymmetric molecules applied to a suitable design for the sensitizers of DSC. The study has been pursued by the theoretical modeling of opto‐electronic properties, the optical and electronic characterizations of dyes and elaboration of efficient devices. The discovery of new synthetic pathways opens the way to innovative designs of TPDO for materials used in organic electronics.
Extensive Reduction in Back Electron Transfer in Twisted Intramolecular Charge‐Transfer (TICT) Coumarin‐Dye‐Sensitized TiO2 Nanoparticles/Film: A Femtosecond Transient Absorption Study
Authors: Debnath Tushar , Maity Partha , Lobo Hyacintha , Singh Balvant , Shankarling Ganapati S. , Ghosh Hirendra N. 
Published: February 2014

AbstractWe report the synthesis, characterization, and optical and electrochemical properties of two structurally similar coumarin dyes (C1 and C2). These dyes have been deployed as sensitizers in TiO2 nanoparticles and thin films, and the effect of molecular structure on interfacial electron‐transfer dynamics has been studied. Steady‐state optical absorption, emission, and time‐resolved emission studies on both C1 and C2, varying the polarity of the solvent and the solution pH, suggest that both photoexcited dyes exist in a locally excited (LE) state in solvents of low polarity. In highly polar solvents, however, C1 exists in an intramolecular charge‐transfer (ICT) state, whereas C2 exists in both ICT and twisted intramolecular charge‐transfer (TICT) states, their populations depending on the degree of polarity of the solvent and the pH of the solution. We have employed femtosecond transient absorption spectroscopy to monitor the charge‐transfer dynamics in C1‐ and C2‐sensitized TiO2 nanoparticles and thin films. Electron injection has been confirmed by direct detection of electrons in the conduction band of TiO2 nanoparticles and of radical cations of the dyes in the visible and near‐IR regions of the transient absorption spectra. Electron injection in both the C1/TiO2 and C2/TiO2 systems has been found to be pulse‐width limited (<100 fs); however, back‐electron‐transfer (BET) dynamics has been found to be slower in the C2/TiO2 system than in the C1/TiO2 system. The involvement of TICT states in C2 is solely responsible for the higher electron injection yield as well as the slower BET process compared to those in the C1/TiO2 system. Further pH‐dependent experiments on C1‐ and C2‐sensitized TiO2 thin films have corroborated the participation of the TICT state in the slower BET process in the C2/TiO2 system.
Synthesis and Reactivity Comparisons of 1‐Methyl‐3‐Substituted Cyclopropene Mini‐tags for Tetrazine Bioorthogonal Reactions
Authors: Yang Jun , Liang Yong , Šečkutė Jolita , Houk K. N. , Devaraj Neal K. 
Published: February 2014

AbstractSubstituted cyclopropenes have recently attracted attention as stable “mini‐tags” that are highly reactive dienophiles with the bioorthogonal tetrazine functional group. Despite this interest, the synthesis of stable cyclopropenes is not trivial and their reactivity patterns are poorly understood. Here, the synthesis and comparison of the reactivity of a series of 1‐methyl‐3‐substituted cyclopropenes with different functional handles is described. The rates at which the various substituted cyclopropenes undergo Diels–Alder cycloadditions with 1,2,4,5‐tetrazines were measured. Depending on the substituents, the rates of cycloadditions vary by over two orders of magnitude. The substituents also have a dramatic effect on aqueous stability. An outcome of these studies is the discovery of a novel 3‐amidomethyl substituted methylcyclopropene tag that reacts twice as fast as the fastest previously disclosed 1‐methyl‐3‐substituted cyclopropene while retaining excellent aqueous stability. Furthermore, this new cyclopropene is better suited for bioconjugation applications and this is demonstrated through using DNA templated tetrazine ligations. The effect of tetrazine structure on cyclopropene reaction rate was also studied. Surprisingly, 3‐amidomethyl substituted methylcyclopropene reacts faster than trans‐cyclooctenol with a sterically hindered and extremely stable tert‐butyl substituted tetrazine. Density functional theory calculations and the distortion/interaction analysis of activation energies provide insights into the origins of these reactivity differences and a guide to the development of future tetrazine coupling partners. The newly disclosed cyclopropenes have kinetic and stability advantages compared to previously reported dienophiles and will be highly useful for applications in organic synthesis, bioorthogonal reactions, and materials science.
Synthesis and Structure of a 1‐Phospha‐2‐boraacenaphthene Derivative and Its Chalcogenation Reactions
Authors: Tsurusaki Akihiro , Sasamori Takahiro , Tokitoh Norihiro 
Published: February 2014

AbstractThe first stable 1‐phospha‐2‐boraacenaphthene 1 was synthesized by the reduction of 1‐dimesitylboryl‐8‐dichlorophosphinonaphthalene (2 a) with elemental magnesium, and it was fully characterized. The chalcogenation reaction of 1 with elemental sulfur or selenium afforded the unique heterocycles, 2‐thia‐ and 2‐selena‐1‐phospha‐3‐boraphenalenes 9 S and 9 Se, respectively, through the insertion of the chalcogen atom into a PB bond of 1. Further chalcogenation of 9 afforded the corresponding phosphine chalcogenides. These newly obtained chalcogenated compounds have been characterized. The unique dynamic behavior of 2‐chalcogena‐1‐phospha‐3‐boraphenalene‐1‐chalcogenides 10 in solution has also been described.
Visible‐Light‐Induced CS Bond Activation: Facile Access to 1,4‐Diketones from β‐Ketosulfones
Authors: Xuan Jun , Feng Zhu‐Jia , Chen Jia‐Rong , Lu Liang‐Qiu , Xiao Wen‐Jing 
Published: February 2014

AbstractA novel method for the synthesis of 1,4‐diketones from β‐ketosulfones was developed by means of a visible light‐induced CS bond activation process. Symmetrical and unsymmetrical 1,4‐diketones can be easily prepared in moderate to good yields.
Trapped in Imidazole: How to Accumulate Multiple Photoelectrons on a Black‐Absorbing Ruthenium Complex
Authors: Zedler Linda , Kupfer Stephan , de Moraes Inês Rabelo , Wächtler Maria , Beckert Rainer , Schmitt Michael , Popp Jürgen , Rau Sven , Dietzek Benjamin 
Published: February 2014

AbstractRuthenium dyes incorporating a 4H‐imidazole chromophore as a ligand exhibit a spectrally broad absorption in the UV/Vis region. Furthermore, they show the ability to store two electrons within the 4H‐imidazole ligand. These features render them promising molecular systems, for example, as inter‐ or intramolecular electron relays. To optimize the structures with respect to their electron‐storage capability, it is crucial to understand the impact of structural changes accompanying photoinduced charge transfer in the electronic intermediates of multistep electron‐transfer processes. The photophysical properties of these (reactive) intermediates might impact the function of the molecular systems quite substantially. However, the spectroscopic study of short‐lived intermediates in stepwise multielectron‐transfer processes is experimentally challenging. To this end, this contribution reports on the electrochemical generation of anions identical to intermediate structures and their spectroscopic characterization by in situ resonance Raman and UV/Vis spectroelectrochemistry and computational methods. Thereby, an efficient two‐electron pathway to the 4H‐imidazole electron‐accepting ligand is identified.
Management of Patients With ST‐Segment Elevation or Non–ST‐Segment Elevation Acute Coronary Syndromes in Cardiac Rehabilitation Centers
Authors: Reibis Rona , Völler Heinz , Gitt Anselm , Jannowitz Christina , Halle Martin , Pittrow David , Hildemann Steven 
Published: February 2014

ABSTRACTBackgroundCurrent data on the management of patients in cardiac rehabilitation (CR) after an acute hospital stay due to ST‐segment elevation or non–ST segment elevation acute coronary syndromes (STE‐ACS or NSTE‐ACS) are limited. We aimed to describe patient characteristics, risk factor management, and lipid target achievement of patients in CR in Germany and compare the 2 groups.HypothesisWith respect to the risk factor pattern and treatment effects during a CR stay, there are important differences between STE‐ACS and NSTE‐ACS patients.MethodsComparison of 7950 patients by STE‐ACS or NSTE‐ACS status in the Transparency Registry to Objectify Guideline‐Oriented Risk Factor Management registry (2010) who underwent an inpatient CR period of about 3 weeks.ResultsSTE‐ACS patients compared to NSTE‐ACS patients were significantly younger (60.5 vs 64.4 years, P < 0.0001), and had diabetes mellitus, hypertension, or any risk factor (exception: smoking) less often. At discharge, in STE‐ACS compared to NSTE‐ACS patients, the low‐density lipoprotein cholesterol (LDL‐C) <100 mg/dL goal was achieved by 75.3% and 76.2%, respectively (LDL‐C <70 mg/dL by 27.7% and 27.4%), the high‐density lipoprotein cholesterol goal of >50 mg/dL in women and >40 mg/dL in men was achieved by 49.3% and 49.0%, respectively, and the triglycerides goal of <150 mg/dl was achievedby 72.3% and 74.3%, respectively (all comparisons not significant). Mean systolic and diastolic blood pressure were 121/74 and 123/74 mm Hg, respectively (P < 0.0001 systolic, diastolic not significant). The maximum exercise capacity was 110 and 102 W, respectively (P < 0.0001), and the maximum walking distance was 581 and 451 meters, respectively (P value not significant).ConclusionsPatients with STE‐ACS and NSTE‐ACS differed moderately in their baseline characteristics. Both groups benefited from the participation in CR, as their lipid profile, blood pressure, and physical fitness improved.
Plasma Soluble ST2 Levels Correlate With Disease Severity and Predict Clinical Worsening in Patients With Pulmonary Arterial Hypertension
Authors: Zheng Ya‐Guo , Yang Tao , He Jian‐Guo , Chen Guo , Liu Zhi‐Hong , Xiong Chang‐Ming , Gu Qing , Ni Xin‐Hai , Zhao Zhi‐Hui 
Published: February 2014

ABSTRACTBackgroundSoluble suppression of tumorigenicity (sST2) has been proposed to be a marker for biomechanical strain and a possible predictor of mortality in patients with chronic heart failure. The use of sST2 in pulmonary arterial hypertension (PAH) has not been well defined.HypothesisPlasma sST2 levels may correlate with the disease severity and predict clinical worsening in PAH.MethodsWe performed a cohort study of 40 idiopathic PAH patients with data on demographics, exercise capacity, echocardiographic parameters, laboratory tests, hemodynamics, and medications. Plasma sST2 was assessed with the high‐sensitivity ST2 ELISA kit at diagnostic catheterization. All patients were followed up from the date of blood sampling. The endpoint was clinical worsening.ResultssST2 was significantly elevated in patients with idiopathic PAH compared with control subjects (28.9 ± 13.9 vs 20.7 ± 7.5 ng/mL, P = 0.003). Pearson correlation analysis revealed that sST2 levels correlated with cardiac index (r = −0.534, P = 0.000) and pulmonary vascular resistance (r = 0.350, P = 0.027), and could reflect disease severity of PAH. After a mean follow‐up of 14 ± 5 months, 12 patients showed clinical worsening. Receiver operating characteristic analysis suggested that sST2 levels >31.4 ng/mL discriminated clinical worsening with a sensitivity and specificity of 83.3% and 78.6%, respectively. Kaplan‐Meier analysis showed that higher sST2 levels (>31.4 ng/mL) were associated with poor clinical outcomes (P = 0.008). Multivariate Cox regression analysis showed that sST2 was an independent predictor of clinical worsening (hazard ratio: 6.067, 95% confidence interval: 1.317–27.948, P = 0.021).ConclusionssST2 correlates with disease severity and is a significant predictor of clinical worsening in patients with PAH.
Crystal Structure of Human Soluble Adenylate Cyclase Reveals a Distinct, Highly Flexible Allosteric Bicarbonate Binding Pocket
Authors: Saalau‐Bethell Susanne M. , Berdini Valerio , Cleasby Anne , Congreve Miles , Coyle Joseph E. , Lock Victoria , Murray Christopher W. , O'Brien M. Alistair , Rich Sharna J. , Sambrook Tracey , Vinkovic Mladen , Yon Jeff R. , Jhoti Harren 
Published: February 2014

AbstractSoluble adenylate cyclases catalyse the synthesis of the second messenger cAMP through the cyclisation of ATP and are the only known enzymes to be directly activated by bicarbonate. Here, we report the first crystal structure of the human enzyme that reveals a pseudosymmetrical arrangement of two catalytic domains to produce a single competent active site and a novel discrete bicarbonate binding pocket. Crystal structures of the apo protein, the protein in complex with α,β‐methylene adenosine 5′‐triphosphate (AMPCPP) and calcium, with the allosteric activator bicarbonate, and also with a number of inhibitors identified using fragment screening, all show a flexible active site that undergoes significant conformational changes on binding of ligands. The resulting nanomolar‐potent inhibitors that were developed bind at both the substrate binding pocket and the allosteric site, and can be used as chemical probes to further elucidate the function of this protein.
Development of a Growth‐Hormone‐Conjugated Nanodiamond Complex for Cancer Therapy
Authors: Chu Hsueh‐Liang , Chen Hung‐Wei , Tseng Shin‐Hua , Hsu Ming‐Hua , Ho Li‐Ping , Chou Fu‐Hsuan , Li MD. PhD. Hsing‐Yuan , Chang Yu‐Chuan , Chen Pei‐Hsin , Tsai Li‐Yun , Chou Ching‐Chung , Chen Jyh Shin , Cheng Tsai‐Mu , Chang Chia‐Ching 
Published: February 2014

AbstractIt is highly desirable to develop a therapeutic, observable nanoparticle complex for specific targeting in cancer therapy. Growth hormone (GH) and its antagonists have been explored as cancer cell‐targeting molecules for both imaging and therapeutic applications. In this study, a low toxicity, biocompatible, therapeutic, and observable GH–nanoparticle complex for specifically targeting growth hormone receptor (GHR) in cancer cells was synthesized by conjugating GH with green fluorescence protein and carboxylated nanodiamond. Moreover, we have shown that this complex can be triggered by laser irradiation to create a “nanoblast” and induce cell death in the A549 non‐small‐cell lung cancer cell line via the apoptotic pathway. This laser‐mediated, cancer‐targeting platform can be widely used in cancer therapy.
Dependence of NMR noise line shapes on tuning, matching, and transmission line properties
Authors: Bendet‐Taicher Eli , Müller Norbert , Jerschow Alexej 
Published: February 2014

ABSTRACTThe tuning and matching conditions of rf circuits, as well as the properties of the transmission lines connecting these to the preamplifier, have direct consequences for NMR probe sensitivity and as for the optimum delivery of rf power to the sample. In addition, tuning/matching conditions influence radiation damping effects, which manifest themselves as fast signal flip‐back and line broadening effects, and can lead to concentration‐dependent frequency shifts. Previous studies have also shown that the appearance of spin‐noise and absorbed circuit noise signals heavily depended on tuning settings. Consequently, all these phenomena are linked together. The mutual connections and interdependences of these effects are highlighted and reviewed here. © 2014 The Authors Concepts in Magnetic Resonance, Part B: Magnetic Resonance Engineering Published by Wiley Periodicals, Inc. Concepts Magn Reson Part B (Magn Reson Engineering) 44B: 1–11, 2014