bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sequential Recognition of Zinc and Pyrophosphate Ions in a Terpyridine‐Functionalized Single Nanochannel
Authors: Zhang Yuqi , Zhou Ru , Zhao Zhiju , Kong Xiang‐Yu , Xie Ganhua , Liu Qian , Li Pei , Zhang Zhen , Xiao Kai , Liu Zhengping , Wen Liping , Jiang Lei 
Published: November 2016

AbstractA highly selective recognition system for zinc(II) and pyrophosphate ions is constructed using a single conical nanochannel covalently functionalized with N′‐{4‐[(2,2′:6′,2′′‐terpyridine)‐4‐yl]benzyl}ethane‐1,2‐diamine (TPYD). The immobilized TPYD acts as a specific coordination site for Zn2+ to form TPYD–Zn2+ complexes in preference over other metal ions, and subsequently, the resulting Zn2+‐coordinated nanochannel can be used as a selective recognition element for the pyrophosphate ion based on the coordination reaction between hydroxyl oxygen atoms of pyrophosphate and Zn2+. Ion recognition is monitored by measuring the current–voltage curves of the solutions. The ionic current of the TPYD‐functionalized system at −2.0 V undergoes a clear decrease after exposure to Zn2+ ions and is followed with an obvious increase after subsequent treatment with a pyrophosphate solution. The change of ionic current can be primarily attributed to the variation of charge density of the nanochannel. This functionalized single nanochannel might provide a simple and universal means to recognize other targets by modifying different functional molecules onto the inner surfaces of nanochannels.
Site‐Specific Reactivity of Ethylene at Distorted Dangling‐Bond Configurations on Si(001)
Authors: Pecher Lisa , Mette Gerson , Dürr Michael , Tonner Ralf 
Published: November 2016

AbstractDifferences in adsorption and reaction energetics for ethylene on Si(001) are reported with respect to distorted dangling‐bond configurations induced by hydrogen precoverage, as obtained by DFT calculations. This can help to understand the influence of surface defects and precoverage on the reactivity of organic molecules on semiconductor surfaces in general. The results show that the reactivity of surface dimers fully enclosed by hydrogen‐covered atoms is essentially unchanged compared to the clean surface. This is confirmed by scanning tunneling microscopy measurements. On the contrary, adsorption sites with partially covered surface dimers show a drastic increase in reactivity. This is due to a lowering of the reaction barrier by more than 50 % relative to the clean surface, which is in line with previous experiments. Adsorption on dimers enclosed by molecule (ethylene)‐covered surface atoms is reported to have a strongly decreased reactivity, as a result of destabilization of the intermediate state due to steric repulsion; this is quantified through periodic energy decomposition analysis. Furthermore, an approach for the calculation of Gibbs energies of adsorption based on statistical thermodynamics considerations is applied to the system. The results show that the loss in molecular entropy leads to a significant destabilization of adsorption states.
Intrinsic Kinetics of Dimethyl Ether Synthesis from Plasma Activation of CO2 Hydrogenation over Cu–Fe–Ce/HZSM‐5
Authors: Su Tongming , Zhou Xinhui , Qin Zuzeng , Ji Hongbing 
Published: November 2016

AbstractCO2 is activated in a plasma reactor followed by hydrogenation over a Cu–Fe–Ce/HZSM‐5 catalyst, and the intrinsic kinetics of the plasma catalytic process are studied. Compared with CO2 hydrogenation using Cu–Fe–Ce/HZSM‐5 alone, the CO2 conversion and the dimethyl ether selectivity for the plasma catalytic process are increased by 16.3 %, and 10.1 %, respectively, indicating that the CO2 was activated by the plasma to promote hydrogenation. A study of the intrinsic kinetics shows that the activation energies of methanol formation, the reverse water–gas shift reaction, and methanol dehydration to dimethyl ether are 149.34, 75.47, and 73.18 kJ mol−1, respectively, which are lower than if Cu–Fe–Ce/HZSM‐5 is used without plasma, indicating that the activation of CO2 in the plasma reduces the activation energy of the hydrogenation reaction and improves the yield of dimethyl ether.
Choice of Capping Group in Tripeptide Hydrogels Influences Viability in the Three‐Dimensional Cell Culture of Tumor Spheroids
Authors: Wojciechowski Jonathan P. , Martin Adam D. , Mason Alexander F. , Fife Christopher M. , Sagnella Sharon M. , Kavallaris Maria , Thordarson Pall 
Published: November 2016

AbstractTwo peptide‐derived low‐molecular‐weight gelators bearing different capping groups, 9‐fluorenylmethyloxycarbonyl (Fmoc) and phenothiazine, were synthesized and their gel networks were characterized. The variation of the N‐terminal capping group affects the viability of these hydrogels as a three‐dimensional cell culture for multicellular tumor spheroids. These results indicate that the phenothiazine capping group is a more biocompatible alternative to the widely used Fmoc moiety.
Applications of Liquid/Liquid Biphasic Oxidations by Hydrogen Peroxide with Ionic Liquids or Deep Eutectic Solvents
Authors: Guajardo Nadia , Carlesi Carlos , Schrebler Rodrigo , Morales Jaime 
Published: November 2016

AbstractThis Minireview focuses on recent applications of ionic liquids (ILs) and deep eutectic solvents (DESs) in biphasic oxidations in which the oxidizing agent corresponds to hydrogen peroxide. Biphasic reactions are accomplished when the substrate presents low or moderate solubility in aqueous (polar) systems and/or when separation of products and byproduct is an issue. The properties of the IL and DES allows the reaction activity to be intensified. On the other hand, the high chemical stability of the ionic solvents allows the use of hydrogen peroxide to minimize solvent degradation and unwanted byproducts. The experimental evidence presented herein shows that ILs and DESs can be used as cocatalysts, catalysts, and solvents to achieve enhanced yields and conversions. The process advantages, in terms of a reduction of volatile solvents, improve the safety and use of the oxidizing agent, which implies the possibility of developing new process improvements in the future.
Density Functional Theory Research into the Reduction Mechanism for the Solvent/Additive in a Sodium‐Ion Battery
Authors: Liu Qi , Mu Daobin , Wu Borong , Wang Lei , Gai Liang , Wu Feng 
Published: November 2016

AbstractThe solid–electrolyte interface (SEI) film in a sodium‐ion battery is closely related to capacity fading and cycling stability of the battery. However, there are few studies on the SEI film of sodium‐ion batteries and the mechanism of SEI film formation is unclear. The mechanism for the reduction of ethylene carbonate (EC), propylene carbonate (PC), vinylene carbonate (VC), ethylene sulfite (ES), 1,3‐propylene sulfite (PS), and fluorinated ethylene carbonate (FEC) is studied by DFT. The reaction activation energies, Gibbs free energies, enthalpies, and structures of the transition states are calculated. It is indicated that VC, ES, and PS additives in the electrolyte are all easier to form organic components in the anode SEI film by one‐electron reduction. The priority of one‐electron reduction to produce organic SEI components is in the order of VC>PC>EC; two‐electron reduction to produce the inorganic Na2CO3 component is different and follows the order of EC>PC>VC. Two‐electron reduction for sulfites ES and PS to form inorganic Na2SO3 is harder than that of carbonate ester reduction. It is also suggested that the one‐ and two‐electron reductive decomposition pathway for FEC is more feasible to produce inorganic NaF components.
Concise Xanthine Synthesis through a Double‐Amidination Reaction of a 6‐Chlorouracil with Amidines using Base‐Metal Catalysis
Authors: Morel Bénédicte , Franck Philippe , Bidange Johan , Sergeyev Sergey , Smith Dan A. , Moseley Jonathan D. , Maes Bert U. W. 
Published: November 2016

AbstractA new and concise route towards xanthines through a double‐amidination reaction is described; consecutive intermolecular C−Cl and intramolecular oxidative C−H amidination. N‐uracil amidines are obtained through SNAE on a 6‐chlorouracil with amidines. Direct Cu‐catalyzed oxidative C−H amidination on these N‐uracil amidines yields polysubstituted xanthines. Sustainable oxidants, tBu2O2 or O2, can be used in this oxidase‐type reaction. The protocol allows for the introduction of N1, N3, N7, and C8 substituents during the xanthine‐scaffold construction, thus avoiding post‐functionalization steps. Both 6‐chlorouracils and amidines are readily available commercially or through synthesis.
Design and ARM‐embedded implementation of a chaotic map‐based multicast scheme for multiuser speech wireless communication
Authors: Gan Qiuye , Yu Simin , Li Chengqing , Lü Jinhu , Lin Zhuosheng , Chen Ping 
Published: November 2016

SummaryThis paper proposes a chaotic map‐based multicast scheme for multiuser speech wireless communication and implements it in an ARM platform. The scheme compresses the digital audio signal decoded by a sound card and then encrypts it with a three‐level chaotic encryption scheme. First, the position of every bit of the compressed data is permuted randomly with a pseudo‐random number sequence (PRNS) generated by a 6‐D chaotic map. Then, the obtained data are further permuted in the level of byte with a PRNS generated by a 7‐D chaotic map. Finally, it is operated with a multiround chaotic stream cipher. The whole system owns the following merits: the redundancy in the original audio file is reduced effectively and the corresponding unicity distance is increased; the balancing point between a high security level of the system and real‐time conduction speed is achieved well. In the ARM implementation, the framework of communication of multicast–multiuser in a subnet and the Internet Group Manage Protocol is adopted to obtain the function of communication between one client and other ones. Comprehensive test results were provided to show the feasibility and security performance of the whole system. Copyright © 2016 John Wiley & Sons, Ltd.
A topology and application‐aware relay path allocation scheme in multipath transport system based on application‐level relay
Authors: Zhang Wei , Ning Zhaolong , Lei Weimin , Chen Zhikui 
Published: November 2016

SummaryThe ever‐increasing transmission requirements of quality of service (QoS)‐sensitive applications, especially real‐time multimedia applications, can hardly be met by the single path routing protocols. Multipath transmission mechanism is a feasible approach to provide QoS for various applications. On the basis of the general framework of multipath transport system based on application‐level relay, we present a relay path allocation scheme, whose goal is to select suitable relay paths, while balancing the overlay traffic among the different domains and relayers. With the application‐layer traffic optimization service under the standardization within the Internet Engineering Task Force (IETF), the controller has the topology‐aware ability to allocate relay paths with excellent routing performance. To further develop the universality of our method, the controller perceives transmission performance of relay overlay network through relayers' performance detection processes and, thus, has the application‐aware ability to allocate relay paths with excellent transmission performance for different applications by consulting application‐specific transmission metrics. Simulation results demonstrate that the proposed relay path allocation algorithm performs well in allocating superior relay paths and can balance the distribution of overlay traffic across domains in different network situations.
Biocatalytic and Bioelectrocatalytic Approaches for the Reduction of Carbon Dioxide using Enzymes
Authors: Schlager Stefanie , Dibenedetto Angela , Aresta Michele , Apaydin Dogukan H. , Dumitru Liviu M. , Neugebauer Helmut , Sariciftci Niyazi S. 
Published: November 2016

AbstractIn the recent decade, CO2 has increasingly been regarded not only as a greenhouse gas but even more as a chemical feedstock for carbon‐based materials. Different strategies have evolved to realize CO2 utilization and conversion into fuels and chemicals. In particular, biological approaches have drawn attention, as natural CO2 conversion serves as a model for many processes. Microorganisms and enzymes have been studied extensively for redox reactions involving CO2. In this review, we focus on monitoring nonliving biocatalyzed reactions for the reduction of CO2 by using enzymes. We depict the opportunities but also challenges associated with utilizing such biocatalysts. Besides the application of enzymes with co‐factors, resembling natural processes, and co‐factor recovery, we also discuss implementation into photochemical and electrochemical techniques.
Improving the convergence behaviour of a fixed‐point‐iteration solver for multiphase flow in porous media
Authors: Salinas P. , Pavlidis D. , Xie Z. , Adam A. , Pain C. C. , Jackson M. D. 
Published: November 2016

SummaryA new method to admit large Courant numbers in the numerical simulation of multiphase flow is presented. The governing equations are discretized in time using an adaptive θ‐method. However, the use of implicit discretizations does not guarantee convergence of the nonlinear solver for large Courant numbers. In this work, a double‐fixed point iteration method with backtracking is presented, which improves both convergence and convergence rate. Moreover, acceleration techniques are presented to yield a more robust nonlinear solver with increased effective convergence rate. The new method reduces the computational effort by strengthening the coupling between saturation and velocity, obtaining an efficient backtracking parameter, using a modified version of Anderson's acceleration and adding vanishing artificial diffusion. © 2016 The Authors. International Journal for Numerical Methods in Fluids Published by John Wiley & Sons Ltd.
Effect of leakage pathway flow properties on thermal signal associated with the leakage from CO2 storage zone
Authors: Mao Yilin , Zeidouni Mehdi , Askari Roohollah 
Published: November 2016

AbstractTemperature can be used to detect the leakage of fluids from the CO2 storage zone. CO2 leakage is accompanied by temperature cooling due to the Joule‐Thomson effect. We investigate the strength of the temperature signals for two scenarios in which leakage occurs either through a leaky well or through a leaky fault. In addition, we identify and analyze the major mechanisms contributing to the temperature signal. A larger pressure drop at shallower depths and thinner caprock thickness can induce more cooling and hence a stronger temperature signal. Furthermore, we study the effect of capillary pressure on the temperature signal as it can reduce the Joule‐Thomson effect after CO2 leakage. The hydraulic properties of the leakage pathway, being a fractured or non‐fractured matrix porous medium, are investigated using dual‐porosity/dual‐permeability models and considering identical permeability to the single porous medium case. The leakage rate increases significantly for dual‐medium models. The further sensitivity analysis contains the effects of leakage pathway flow properties: fracture permeability, fracture spacing, and porosity. We also extend our models to consider the injection zone as a naturally fractured reservoir, and further incorporate an above‐zone monitoring interval as another naturally fractured reservoir as well. © 2016 Society of Chemical Industry and John Wiley & Sons, Ltd.
Reappraising hyalinizing clear cell carcinoma: A population‐based study with molecular confirmation
Authors: Hernandez–Prera Juan C. , Kwan Ricky , Tripodi Joseph , Chiosea Simion , Cordon–Cardo Carlos , Najfeld Vesna , Demicco Elizabeth G. 
Published: November 2016

ABSTRACTBackgroundHyalinizing clear cell carcinoma (HCCC) is a rare malignancy, characterized by EWSR1‐ATF1 gene fusion, whose behavior is poorly understood, as it was for many years considered a diagnosis of exclusion.MethodsAll available salivary gland carcinomas (n = 594) from our institution were reviewed. Diagnosis of HCCC was confirmed by fluorescence in situ hybridization (FISH) for EWSR1. Literature review was performed.ResultsWe found 15 patients with HCCCs (10 women, 5 men), 13 with EWSR1 rearrangement. Median age at diagnosis was 57 years (range, 31–87 years). Oral cavity (n = 9) and base of tongue (n = 4) were the most frequent primary sites. Combining our cases with those identified in literature review, the 10‐year risk of local recurrence and locoregional nodal metastasis were 49% and 15%, respectively.ConclusionMolecularly confirmed HCCC accounted for 2.5% of salivary gland malignancies at our institution. HCCCs are indolent tumors with a propensity for locoregional recurrence. © 2016 Wiley Periodicals, Inc. Head Neck 39: 503–511, 2017
Dynamics of intracellular processes in live‐cell systems unveiled by fluorescence correlation microscopy
Authors: González Bardeci Nicolás , Angiolini Juan Francisco , De Rossi María Cecilia , Bruno Luciana , Levi Valeria 
Published: November 2016

AbstractFluorescence fluctuation‐based methods are non‐invasive microscopy tools especially suited for the study of dynamical aspects of biological processes. These methods examine spontaneous intensity fluctuations produced by fluorescent molecules moving through the small, femtoliter‐sized observation volume defined in confocal and multiphoton microscopes. The quantitative analysis of the intensity trace provides information on the processes producing the fluctuations that include diffusion, binding interactions, chemical reactions and photophysical phenomena. In this review, we present the basic principles of the most widespread fluctuation‐based methods, discuss their implementation in standard confocal microscopes and briefly revise some examples of their applications to address relevant questions in living cells. The ultimate goal of these methods in the Cell Biology field is to observe biomolecules as they move, interact with targets and perform their biological action in the natural context. © 2016 IUBMB Life, 69(1):8–15, 2017
Hydrogen peroxide modulates energy metabolism and oxidative stress in cultures of permanent human Müller cells MIO‐M1
Authors: Peters Sven , Griebsch Max , Klemm Matthias , Haueisen Jens , Hammer Martin 
Published: November 2016

In this study the influence of hydrogen peroxide (H2O2) on the redox state, NADH protein binding, and mitochondrial membrane potential in Müller cells is investigated. Cultures of permanent human Müller cells MIO‐M1 were exposed to H2O2in 75 µM and 150 µM concentration for two hours. Fluorescence emission spectra and lifetimes were measured by two‐photon microscopy (excitation wavelength: 740 nm) at the mitochondria which were identified in the microscopic images by their fluorescence properties (spectra and intensity). Two hours of H2O2exposure did not impair viability of MIO‐M1 cells in culture. Whereas the ratio of flavine‐ to NADH fluorescence intensity did not change under either H2O2concentration, the mean lifetime was significantly different between controls, not exposed to H2O2, and the 150 µM H2O2exposure (972 ± 63 ps vs. 1152 ± 64 ps,p= 0.014). One hour after cessation of the H2O2exposure, the value retuned to that of the control (983 ± 36 ps). A hyperpolarization of the mitochondrial membrane under 150 µM H2O2was found. These findings suggest a shift form free to protein‐bound NADH in mitochondria as well as a hyperpolarization of their inner membrane which could be related to an impairment of Müller cell function despite their preserved viability.Exposure of human Müller cells to hydrogen peroxide for two hours results in a reversible change of protein binding of mitochondrial NADH upon unchanged redox ratio. The mitochondrial membrane potential is increased during exposure.magnified imageExposure of human Müller cells to hydrogen peroxide for two hours results in a reversible change of protein binding of mitochondrial NADH upon unchanged redox ratio. The mitochondrial membrane potential is increased during exposure.
Hormesis, cellular stress response and neuroinflammation in schizophrenia: Early onset versus late onset state
Authors: Calabrese Vittorio , Giordano James , Crupi Rosalia , Di Paola Rosanna , Ruggieri Martino , Bianchini Rio , Ontario Maria Laura , Cuzzocrea Salvatore , Calabrese Edward J. 
Published: November 2016

Abnormal redox homeostasis and oxidative stress have been proposed to play a role in the etiology of several neuropsychiatric spectrum disorders. Emerging interest has recently focused on markers of oxidative stress and neuroinflammation in schizophrenic spectrum disorders, at least in particular subgroups of patients. Altered expression of genes related to oxidative stress, oxidative damage to DNA, protein and lipids, as well as reduced glutathione levels in central and peripheral tissues could act synergistically, and contribute to the course of the disease. Herein, we discuss cellular mechanisms that may be operative in neuroinflammation and contributory to schizophrenia. We address modulation of endogenous cellular defense mechanisms as a potentially innovative approach to therapeutics for schizophrenia, and other neuropsychiatric conditions that are associated with neuroinflammation. Specifically, we discuss the emerging role of heme oxygenase as prominent member of neuroprotective network in redox stress responsive mechanisms, as well as the importance of glutathione relevant in schizophrenia pathophysiology. Finally we introduce the hormetic dose response concept as relevant and important to neuroprotection, and review hormetic mechanisms as possible approaches to manipulation of neuroinflammatory targets that may be viable for treating schizophrenia spectrum disorders. © 2016 Wiley Periodicals, Inc.
Perfusion has no effect on the in vivo CEST effect from Cr (CrCEST) in skeletal muscle
Authors: Kogan Feliks , Stafford Randall B. , Englund Erin K. , Gold Garry E. , Hariharan Hari , Detre John A. , Reddy Ravinder 
Published: November 2016

AbstractCreatine, a key component of muscle energy metabolism, exhibits a chemical exchange saturation transfer (CEST) effect between its amine group and bulk water, which has been exploited to spatially and temporally map creatine changes in skeletal muscle before and after exercise. In addition, exercise leads to an increase in muscle perfusion. In this work, we determined the effects of perfused blood on the CEST effects from creatine in skeletal muscle. Experiments were performed on healthy human subjects (n = 5) on a whole‐body Siemens 7T magnetic resonance imaging (MRI) scanner with a 28‐channel radiofrequency (RF) coil. Reactive hyperemia, induced by inflation and subsequent deflation of a pressure cuff secured around the thigh, was used to increase tissue perfusion whilst maintaining the levels of creatine kinase metabolites. CEST, arterial spin labeling (ASL) and 31P MRS data were acquired at baseline and for 6 min after cuff deflation. Reactive hyperemia resulted in substantial increases in perfusion in human skeletal muscle of the lower leg as measured by the ASL mean percentage difference. However, no significant changes in CrCEST asymmetry (CrCESTasym) or 31P MRS‐derived PCr levels of skeletal muscle were observed following cuff deflation. This work demonstrates that perfusion changes do not have a major confounding effect on CrCEST measurements.