bluuebunny/crossref_metadata_2025_split huggingface dataset:
Insolubilization and thermal stabilization of a long‐chain polyester by noncatalyzed melt‐polycondensation synthesis in air
Authors: Benítez José Jesús , Heredia‐Guerrero José Alejandro , Cruz‐Carrillo Miguel Antonio , Barthel Markus Joachim , Knicker Heike Elisabeth , Heredia Antonio 
Published: August 2016

ABSTRACTSelf‐standing films of poly(ω‐hydroxyl hexadecanoic acid) [poly(ω‐OHC16)] have been prepared by noncatalyzed melt‐polycondensation in air at 150, 175, and 200 °C. Poly(ω‐OHC16)s obtained are characterized as polyesters by infrared spectroscopy (FT‐IR) and solid state magic angle spinning 13C nuclear magnetic resonance (13C MAS‐NMR). Structurally, poly(ω‐OHC16)s are quite crystalline as revealed by wide angle X‐ray diffraction (WAXD). The presence of oxygen in the reaction atmosphere causes a mild oxidation in the form of peroxyester species, tentatively at the interphase between poly(ω‐OHC16) crystallites, and the structure amorphization. The interfacial peroxyester phase ends up in the encapsulation of the polyester grains and provides a barrier towards the action of solvents. Thermal stabilization and insolubility resulting from the synthesis conditions used are interesting features to prepare solvent and heat resistant poly(ω‐OHC16) coatings. Thus, a few microns thick poly(ω‐OHC16) layer has been fabricated on aluminum foil and its resistivity towards a chloroform:methanol (1:1, v:v) mixture has been confirmed. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44350.
RSM optimization of HSA/IL1Ra in Pichia pastoris overexpression strain and study of its in vivo activity in reducing hyperglycemia of GK rats
Authors: Liu Wenhui , Zhao Wenbin , Lai Jun , Shen Qi , Xu Yingchun , Pan Liqiang , Chen Shuqing 
Published: August 2016

AbstractHuman serum albumin (HSA) and interleukin‐1 receptor antagonist (IL1Ra) fusion protein is a potential long‐acting drug in the treatment of type 2 diabetes. Previously, the expression level of HSA/IL1Ra in Pichia pastoris was successfully improved by increasing the gene copy number and coexpression with chaperone (protein disulfide isomerase) in our laboratory. However, the overexpression strain resulted in low production of high‐ cell‐density fermentation. In this study, the culture medium was optimized in both flask and fermenter, and the optimum culture medium notably increased the productivity and stability of HSA/IL1Ra. To further improve the expression, response surface methodology was used to further optimize the culture condition through modeling three selected parameters (induction pH, induction temperature [T], and maximum methanol feed rate [Vm]). The maximum yield of HSA/IL1Ra reached 1.1 g/L (10‐fold higher than original fermentation condition) under the optimized culture condition (pH 7.0, T = 29 ℃ and Vm = 4.82 mL/L/H) in a 5‐L fermenter. In addition, the degradation position of HSA/IL1Ra during fermentation was determined to be K571, serving as a potential target for genetic modification strategies to reduce the degradation. Finally, the in vivo activity study showed that HSA/IL1Ra maintained the therapeutic effect of IL1Ra in type 2 diabetes model rats meanwhile reducing the frequency of administration.
Quimera: The easy way to simulate Foundation Fieldbus applications
Authors: Viegas Vítor , Postolache Octavian Adrian , Girão Pedro M. B. Silva , Pereira José M. Dias 
Published: August 2016

ABSTRACTThe paper presents a simulation tool that emulates the development environment of Foundation Fieldbus (FF) applications. The idea is to use the resources provided by LabVIEW®—in particular its dataflow programming paradigm—to design, execute, and debug FF control applications. Function blocks are implemented as virtual instruments, data links are represented by virtual wires, and bus monitoring tools are replaced by application debugging tools. The simulator can easily be connected to virtual (simulated) processes or to physical (real) processes. Tests were made to evaluate the capabilities of the simulator and to assess its degree of fidelity against commercial FF systems. The goal was to release an easy‐to‐use, low‐cost training tool to disseminate knowledge about process control using the FF technology. © 2016 Wiley Periodicals, Inc. Comput Appl Eng Educ 24:914–925, 2016; View this article online at wileyonlinelibrary.com/journal/cae; DOI 10.1002/cae.21761
Iridium(1 1 1), Iridium(1 1 0), and Ruthenium(0 0 0 1) Single Crystals as Model Catalysts for the Oxygen Evolution Reaction: Insights into the Electrochemical Oxide Formation and Electrocatalytic Activity
Authors: Özer Ebru , Spöri Camillo , Reier Tobias , Strasser Peter 
Published: August 2016

AbstractWe report a comparative study on the influence of generic electrochemical activation–oxidation protocols on the resulting surface oxides of Ir(1 1 1) and (1 1 0) and Ru(0 0 0 1) single crystals and their electrocatalytic reactivity for the oxygen evolution reaction. Well‐defined single‐crystal electrodes were prepared in a custom‐made chamber that combines inductive thermal annealing and electrochemistry. The clean surfaces were analyzed for their electrocatalytic oxygen evolution activities and oxidation behavior. Three different oxidation protocols were used, which revealed a strong activity dependence on the duration and upper potential limit of the electrochemical oxidation. The resulting changes of the surface were followed by using cyclic voltammetry and impedance spectroscopy. Important differences between the two faces of Ir in terms of surface morphology of the formed oxide were identified, which allowed us to draw conclusions for preferable crystal faces in nanoparticle catalysts.
Measurement of Micro Kinetics of Hydrogenation in Liquid Phase Using Raman Spectroscopy
Authors: Fischer Armin , Müller Karsten , Arlt Wolfgang 
Published: August 2016

AbstractHydrogenation of liquid organic hydrogen carriers is usually carried out in liquid phase. To measure the kinetics of this hydrogenation, an experimental setup using in situ Raman spectroscopy for analysis of the reaction mixture is proposed. With this setup it is possible to perform hydrogenation reactions at temperatures of up to 573 K and pressures up to 25 MPa. For validation of the experimental setup the hydrogenation of 1‐octene was measured in liquid phase. The reaction progress can be monitored in detail by Raman spectroscopy. To determine kinetic parameters from the experimental data, two modeling approaches were applied: a classic kinetic model and a thermodynamic kinetic model. The results were compared to literature data.
Prediction of Flow Patterns of Rotating Inclined Reactors by Using a Modified Permeability Approach
Authors: Subramanian Kumar , Winkler Manuel , Härting Hans‐Ulrich , Schubert Markus 
Published: August 2016

AbstractA new inclined rotating tubular fixed bed reactor was recently suggested for process intensification of heterogeneous catalytic multiphase reactions. Favorable operating conditions can be achieved by operating the reactor in a wetting intermittency mode by periodic catalyst immersion in a stratified gas‐liquid flow. This flow pattern adjustment, which requires the careful selection of reactor inclination and rotation, eventually enhances the reaction rate. To predict the flow patterns by means of computational fluid dynamics, a 3D model based on the relative permeability approach was developed, in which gas and liquid phases flow concurrently downwards through the inclined rotating tubular fixed bed reactor. The model can clearly predict the four evolving patterns, depending on the operating conditions. The model was capable of correctly predicting the hydrodynamics for aqueous liquid mixtures with varying viscosity and surface tension.
Di‐ and Triphosphate Recognition and Sensing with Mono‐ and Dinuclear Fluorescent Zinc(II) Complexes: Clues for the Design of Selective Chemosensors for Anions in Aqueous Media
Authors: Bartoli Francesco , Bencini Andrea , Garau Alessandra , Giorgi Claudia , Lippolis Vito , Lunghi Alessandro , Totti Federico , Valtancoli Barbara 
Published: August 2016

AbstractThe synthesis of a new ligand (L1) containing two 1,4,7‐triazacyclononane ([9]aneN3) moieties linked by a 4,5‐dimethylenacridine unit is reported. The binding and fluorescence sensing properties toward Cu2+, Zn2+, Cd2+, and Pb2+ of L1 and receptor L2, composed of two [9]aneN3 macrocycles bridged by a 6,6′′‐dimethylen‐2,2′:6′,2′′‐terpyridine unit, have been studied by coupling potentiometric, UV/Vis absorption, and emission measurements in aqueous media. Both receptors can selectively detect Zn2+ thanks to fluorescence emission enhancement upon metal binding. The analysis of the binding and sensing properties of the Zn2+ complexes toward inorganic anions revealed that the dinuclear Zn2+ complex of L1 selectively binds and senses the triphosphate anion (TP), whereas the mononuclear Zn2+ complex of L2 displays selective recognition of diphosphate (DP). Binding of TP or DP induces emission quenching of the Zn2+ complexes with L1 and L2, respectively. These results are exploited to discuss the role played by pH, number of coordinated metal cations, and binding ability of the bridging units in metal and/or anion coordination and sensing.
Structural Diversity in Alkali Metal and Alkali Metal Magnesiate Chemistry of the Bulky 2,6‐Diisopropyl‐N‐(trimethylsilyl)anilino Ligand
Authors: Fuentes M. Ángeles , Zabala Andoni , Kennedy Alan R. , Mulvey Robert E. 
Published: August 2016

AbstractBulky amido ligands are precious in s‐block chemistry, since they can implant complementary strong basic and weak nucleophilic properties within compounds. Recent work has shown the pivotal importance of the base structure with enhancement of basicity and extraordinary regioselectivities possible for cyclic alkali metal magnesiates containing mixed n‐butyl/amido ligand sets. This work advances alkali metal and alkali metal magnesiate chemistry of the bulky arylsilyl amido ligand [N(SiMe3)(Dipp)]− (Dipp=2,6‐iPr2‐C6H3). Infinite chain structures of the parent sodium and potassium amides are disclosed, adding to the few known crystallographically characterised unsolvated s‐block metal amides. Solvation by N,N,N′,N′′,N′′‐pentamethyldiethylenetriamine (PMDETA) or N,N,N′,N′‐tetramethylethylenediamine (TMEDA) gives molecular variants of the lithium and sodium amides; whereas for potassium, PMDETA gives a molecular structure, TMEDA affords a novel, hemi‐solvated infinite chain. Crystal structures of the first magnesiate examples of this amide in [MMg{N(SiMe3)(Dipp)}2(μ‐nBu)]∞ (M=Na or K) are also revealed, though these breakdown to their homometallic components in donor solvents as revealed through NMR and DOSY studies.
Tetrazine Click Chemistry for the Modification of 1‐Hydroxy‐1,1‐methylenebisphosphonic Acids: Towards Bio‐orthogonal Functionalization of Gold Nanoparticles
Authors: Aufaure Romain , Hardouin Julie , Millot Nadine , Motte Laurence , Lalatonne Yoann , Guénin Erwann 
Published: August 2016

AbstractInverse electron demand Diels–Alder (iEDDA) was evaluated for the functionalization of gold nanoparticles. The reaction was first modelled with the free coating molecule 1‐hydroxy‐1,1‐methylenebisphosphonate bearing an alkene functionality (HMBPene). A model tetrazine 3,6‐dipyridin‐2‐yl‐1,2,4,5‐tetrazine (pyTz) was used, kinetic of the reaction was calculated and coupling products were analysed by NMR and HRMS. The reaction was then transposed at the nanoparticle surface. Gold nanoparticles bearing an alkene functionality were obtained using a one‐pot methodology with HMBPene and the tetrazine click chemistry was evaluated at their surface using pyTz. The successful coupling was assessed by XPS measurements. This click‐methodology was extended to the conjugation of a NIR probe at the NP surface.
Reducing Capsule Based on Electron Programming: Versatile Synthesizer for Size‐Controlled Ultra‐Small Metal Clusters
Authors: Kambe Tetsuya , Imaoka Takane , Yamamoto Kimihisa 
Published: August 2016

AbstractControlled reducing capsules with a specific number of reducing electrons were achieved by appropriately placed BH3 units in the dendritic polyphenylazomethines (DPAs). Using the 1:1 coordination fashion on their basic branches with radius affinity gradient, the 4th generation DPA (DPAG4) possessing four BH3 units in the central positions was prepared as a template synthesizer for size‐controlled ultra‐small metal clusters. This was well‐demonstrated by reduction of Ag, Pt, and other metal ions resulting in monodispersed ultra‐small clusters.
Two‐Component Self‐Assembly: Hierarchical Formation of pH‐Switchable Supramolecular Networks by π–π Induced Aggregation of Ion Pairs
Authors: Samanta Krishnananda , Ehlers Martin , Schmuck Carsten 
Published: August 2016

AbstractTwo‐component self‐assembly is a promising approach to construct functional nanomaterials. Interaction of a flexible guanidiniocarbonyl pyrrole tetra‐cation (1) with naphthalene diimide dicarboxylic acid (NDIDC) in aqueous DMSO leads to the formation of supramolecular networks. First, the carboxylate groups of NDIDC bind to the guanidiniocarbonyl pyrrole cations of 1 in a 1:2 stoichiometry. Further π–π induced aggregation then leads to 3D networks, as established by dynamic light scattering studies (DLS), NMR, fluorescence titration, viscosity measurements, AFM, and TEM microscopy. Due to ion pairing, the resulting aggregates can be switched between the monomers and the aggregates reversibly using external stimuli like protonation or deprotonation. At high concentration, a stable colloidal solution is formed, which shows an extensive Tyndall effect. Increasing the concentrations even further leads to formation of a supramolecular gel.
Phylogeographic structure in long‐tailed voles (Rodentia: Arvicolinae) belies the complex Pleistocene history of isolation, divergence, and recolonization of Northwest North America's fauna
Authors: Sawyer Yadéeh E. , Cook Joseph A. 
Published: August 2016

AbstractQuaternary climate fluctuations restructured biodiversity across North American high latitudes through repeated episodes of range contraction, population isolation and divergence, and subsequent expansion. Identifying how species responded to changing environmental conditions not only allows us to explore the mode and tempo of evolution in northern taxa, but also provides a basis for forecasting future biotic response across the highly variable topography of western North America. Using a multilocus approach under a Bayesian coalescent framework, we investigated the phylogeography of a wide‐ranging mammal, the long‐tailed vole, Microtus longicaudus. We focused on populations along the North Pacific Coast to refine our understanding of diversification by exploring the potentially compounding roles of multiple glacial refugia and more recent fragmentation of an extensive coastal archipelago. Through a combination of genetic data and species distribution models (SDMs), we found that historical climate variability influenced contemporary genetic structure, with multiple isolated locations of persistence (refugia) producing multiple divergent lineages (Beringian or northern, southeast Alaska or coastal, and southern or continental) during glacial advances. These vole lineages all occur along the North Pacific Coast where the confluence of numerous independent lineages in other species has produced overlapping zones of secondary contact, collectively a suture zone. Finally, we detected high levels of neoendemism due to complex island geography that developed in the last 10,000 years with the rising sea levels of the Holocene.
Enhanced Potentiometric Detection of Hydrogen Peroxide Using a Platinum Electrode Coated with Nafion
Authors: Parrilla Marc , Cánovas Rocío , Andrade Francisco J. 
Published: August 2016

AbstractThe potentiometric response to hydrogen peroxide of a platinum electrode coated with a layer of Nafion is presented. The results show that the Nafion membrane acts as an effective permselective barrier, thus significantly reducing the response to some redox active species, such as ascorbate. Even more interesting, these coated electrodes show a significantly enhanced sensitivity to hydrogen peroxide (H2O2) when the measurements are performed in solutions of high ionic strength. The influence of pH, ionic strength and supporting electrolyte on this enhancement are presented. Under optimized conditions these coated electrodes show a linear dependence with the logarithm of the concentration of H2O2, with sensitivities of −125.1±5.9 mV decade−1 (several times higher than the bare electrodes) and a linear range that spans from 10−5 M to 10−3 M of H2O2. Preliminary studies suggest that the coupling between the redox potential on the Pt electrode and the Donnan potential of the membrane plays a role on this enhancement. Considering this improved sensitivity, selectivity, stability and linear ranges, this system shows promise as a future platform to build enzyme‐based potentiometric biosensors.
Mesoporous Spinel Nanofibers and Nitrogen‐doped Carbon Nanotubes as High‐Performance Electrocatalyst for Oxygen Reduction in Alkaline and Neutral Media
Authors: Wang Haijun , Wang Juan , Zhong Qin , Zhang Guangyao , Bu Yunfei 
Published: August 2016

AbstractA mesoporous spinel nanofibers consisting of mixed transition‐metal oxides (Mn0.6Cu0.4Co2O4; MCCO) were synthesized using a facile electrospinning technique followed by a thermal treatment process. The porous structure results in a high surface area of the MCCO nanofibers, which plays a beneficial role in improving the electrocatalytic properties. By adding nitrogen‐doped carbon nanotubes (N‐CNT), a composite electrocatalyst MCCO/N‐CNT was fabricated. The ORR performances were evaluated in alkaline and neutral media. The results suggest that MCCO/N‐CNT hybrid can be used as a promising ORR catalyst for fuel‐cell applications.
Liquid–Solid Phase‐Change Behavior of Diethylenetriamine in Nonaqueous Systems for Carbon Dioxide Absorption
Authors: Zhang Zheng , Zhao Wenbo , Nong Jiejing , Feng Dong , Li Yanhong , Chen Yuan , Chen Jian 
Published: August 2016

AbstractConventional amine scrubbing systems for carbon dioxide capture require a large amount of energy to regenerate the absorbent. Theoretically, if CO2‐captured product can be separated from the liquid counterpart, and only this product need to be heated for desorption, the energy efficiency for CO2 capture can be improved greatly. In the present work, diethylenetriamine (DETA) dissolved in ethanol, diethylene glycol dimethyl ether, N‐methyl‐pyrrolidone, or dimethyl carbonate can absorb CO2 to result in liquid–solid phase‐change in addition to making the reaction to achieve its stoichiometric maximum. The results show that the different organic solvents have no influence on the formation of precipitate. Single‐crystal structure analysis indicates a DETA–carbamate is formed with equimolar CO2 absorption. The absorption–desorption cycles using microwave heating shows that the system has a relatively stable cycling performance.
Metabolomic responses to sublethal contaminant exposure in neonate and adult Daphnia magna
Authors: Wagner Nicole D. , Simpson André J. , Simpson Myrna J. 
Published: August 2016

Abstract

The use of consumer products and pharmaceuticals that act as contaminants entering waterways through runoff and wastewater effluents alters aquatic ecosystem health. Traditional toxicological endpoints may underestimate the toxicity of contaminants, as lethal concentrations are often orders of magnitude higher than those found within freshwater ecosystems. While newer techniques examine the metabolic responses of sublethal contaminant exposure, there has been no direct comparison with ontogeny in Daphnia. It was hypothesized that Daphnia magna would have distinct metabolic changes after 3 different sublethal contaminant exposures, because of differences in the toxic mode of action and ontogeny. To test this hypothesis, the proton nuclear magnetic resonance metabolomic profiles were measured in D. magna aged day 0 and 18 after exposure to 28% of the lethal concentration of 50% of organisms tested (LC50) of atrazine, propranolol, and perfluorooctanesulfonic acid (PFOS) for 48 h. Principal component analysis revealed significant separation of contaminants from the control daphnids in both neonates and adults exposed to propranolol and PFOS. In contrast, atrazine exposure caused separation from the controls in only the adult D. magna. Minimal ontogenetic changes in the targeted metabolites were seen after exposure to propranolol. For both atrazine and PFOS exposures ontogeny exhibited unique changes in the targeted metabolites. These results indicate that, depending on the contaminant studied, neonates and adults respond uniquely to sublethal contaminant exposure. Environ Toxicol Chem 2017;36:938–946. © 2016 SETAC
High Efficiency DC/AC/DC Converter Based on Synchronous Rectifier for Proton Exchange Membrane Fuel Cells
Authors: Depernet D. , Gustin F. , Hissel D. 
Published: August 2016

AbstractThis paper deals with the efficiency improvement of a DC/AC/DC converter used for proton exchange membrane fuel cell (PEMFC) coupling to an electrical vehicle DC bus. The power converter is based on a MOSFET inverter stage, a high frequency planar technology transformer stage and a full bridge diode rectifier output stage. The diode rectifier is a source of losses due to the diode forward voltage, which may be reduced by implementation of synchronous rectifier technology, especially for high output current. Mosfets with low drain‐to‐source on‐resistance are coupled to the diodes to reduce the losses. Control principle of this converter is presented with losses modeling and efficiency study in order to highlight the advantages of the synchronous rectification. Efficiency improvement is quantified from a comparison study with technological choices including silicon carbide (SiC) MOSFET and Schottky diodes. This study points out that the synchronous rectification becomes really relevant for an actual scale‐1 application and not for our reduced scale laboratory power converter. Finally, experimental validation of the control is presented with our laboratory test bench. The realization of a scale‐1 converter is under study to experimentally validate the advantages of the proposed synchronous rectification.
Microstructure and Polarization Studies on Interlayer Free La0.65Sr0.3Co0.2Fe0.8O3–δ Cathodes Fabricated on Yttria Stabilized Zirconia by Solution Precursor Plasma Spraying
Authors: Shri Prakash B. , Balaji N. , Senthil Kumar S. , Aruna S. T. 
Published: August 2016

AbstractNano‐structured cathodes of La0.65Sr0.3Co0.2Fe0.8O3–δ (LSCF) are fabricated by solution precursor plasma spraying (SPPS) on yttria stabilized zirconia (YSZ) electrolytes (LSCF‐SPPS‐YSZ). Phase pure LSCF is obtained at all plasma power. Performances of LSCF‐SPPS‐YSZ cathodes are compared with conventionally prepared LSCF cathodes on YSZ (LSCF‐C‐YSZ) and gadolinium doped ceria (GDC) (LSCF‐C‐GDC) electrolytes. High Rp is observed in the LSCF‐C‐YSZ (∼42 Ohm cm2 at 700 °C) followed by LSCF‐C‐GDC (Rp ∼ 1.5 Ohm cm2 at 700 °C) cathodes. Performance of the LSCF‐SPPS‐YSZ cathodes (Rp ∼ 0.1 Ohm cm2 at 700 °C) is found to be even superior to the performance of LSCF‐C‐GDC cathodes. High performance in LSCF‐SPPS‐YSZ cathodes is attributed to its nano‐structure and absence of any interfacial insulating phase which may be attributed to the low temperature at the interaction point of LSCF and YSZ and low interaction time between LSCF and YSZ during SPPS process. In the time scale of 100 h, no change in the polarization resistances is observed at 750 °C. Based on the literature and from the present studies it can be stated that SOFC with YSZ electrolyte and LSCF‐SPPS‐YSZ cathode can be operated at 750 °C for a longer duration of time and good performance can probably be achieved.