bluuebunny/crossref_metadata_2025_split huggingface dataset:
Copper‐Catalyzed Regioselective Formal Allylboration of Aryl‐Substituted Terminal Alkynes with Bis(pinacolato)diboron and Allyl Halides/Sulfonates
Authors: Jing Haitong , Feng Xiaorui , Guo Minjie , Zhou Sen , Li Yanlin , Zhang Jiacheng , Zhao Wentao , Tang Xiangyang , Wang Guangwei 
Published: May 2017

AbstractA copper‐catalyzed formal allylboration of terminal alkynes using allyl bromides or sulfonates as electrophiles has been achieved. This method exhibits good regio‐/stereoselectivity and good functional‐group tolerance for various substituents on the aromatic rings of arylethynes. Through this strategy, various trisubstituted vinyl pinacol boronic esters with a 1,4‐diene skeleton have been constructed. In order to demonstrate the utility of this method, the resulting 1,4‐dienes with boron substitution were further used in transformations such as Suzuki coupling, oxidation, halogenation, and so on, leading to various important compounds.
Umkehr der Polarität: α‐Aminierungen von Carbonylverbindungen mit Stickstoffnukleophilen
Authors: de la Torre Aurélien , Tona Veronica , Maulide Nuno 
Published: May 2017

AbstractDie Synthese von α‐Aminocarbonylverbindungen ist eine wichtige Herausforderung in der Synthese biologisch essenzieller Strukturen. Da bei den klassischen Ansätzen Enole oder Enolate in Verbindung mit einer elektrophilen Stickstoffquelle verwendet werden, ist bei diesen Methoden normalerweise eine weitere Umwandlung erforderlich, um die gewünschten Zielverbindungen zu realisieren. In den letzten Jahren wurde ein neuer Ansatz entwickelt, bei dem nukleophile Stickstoffquellen zusammen mit einem Oxidans direkt eingesetzt werden. Dieser Ansatz hat den Vorteil, dass er in einer Eintopfreaktion zur biologisch relevanten α‐Aminoverbindung führt, ohne dass eine weitere Umwandlung notwendig wäre. In diesem Kurzaufsatz werden die jüngsten Fortschritte in dem aufstrebenden Gebiet der oxidativen α‐Aminierungsreaktionen unter Verwendung von nukleophilen Stickstoffquellen dargelegt.
Self‐Assembled Zinc/Cystine‐Based Chloroplast Mimics Capable of Photoenzymatic Reactions for Sustainable Fuel Synthesis
Authors: Liu Kai , Yuan Chengqian , Zou Qianli , Xie Zengchun , Yan Xuehai 
Published: May 2017

AbstractPrototypes of biosystems provide good blueprints for the design and creation of biomimetic systems. However, mimicking both the sophisticated natural structures and their complex biological functions still remains a great challenge. Herein, chloroplast mimics have been fabricated by one‐step bioinspired amino acid mineralization and simultaneous integration of catalytically active units. Hierarchically structured crystals were obtained by the metal‐ion‐directed self‐assembly of cystine (the oxidized dimer of the amino acid cysteine), with a porous structure and stacks of nanorods, which show similar architectural principles to chloroplasts. Porphyrins and enzymes can both be encapsulated inside the crystal during mineralization, rendering the crystal photocatalytically and enzymatically active for an efficient and sustainable synthesis of hydrogen and acetaldehyde in a coupled photoenzymatic reaction.
Selected Copper‐Based Reactions for C−N, C−O, C−S, and C−C Bond Formation
Authors: Bhunia Subhajit , Pawar Govind Goroba , Kumar S. Vijay , Jiang Yongwen , Ma Dawei 
Published: May 2017

AbstractMetal‐catalyzed cross‐coupling reactions belong to the most important transformations in organic synthesis. Copper catalysis has received great attention owing to the low toxicity and low cost of copper. However, traditional Ullmann‐type couplings suffer from limited substrate scopes and harsh reaction conditions. The introduction of several bidentate ligands, such as amino acids, diamines, 1,3‐diketones, and oxalic diamides, over the past two decades has totally changed this situation as these ligands enable the copper‐catalyzed coupling of aryl halides and nucleophiles at both low reaction temperatures and catalyst loadings. The reaction scope has also been greatly expanded, rendering this copper‐based cross‐coupling attractive for both academia and industry. In this Review, we have summarized the latest progress in the development of useful reaction conditions for the coupling of (hetero)aryl halides with different nucleophiles. Additionally, recent advances in copper‐catalyzed coupling reactions with aryl boronates and the copper‐based trifluoromethylation of aromatic electrophiles will be discussed.
Influence of electrolytes of Li salts, EMIMBF4, and mixed phases on electrochemical and physical properties of Nafion membrane
Authors: Safari Maryam , Naji Leila , Baker Richard T. , Afshar Taromi Faramarz 
Published: May 2017

ABSTRACTElectrolyte‐soaked Nafion is commonly used as an ionic polymer in soft actuators. Here, a multitechnique investigation was applied to correlate the electrochemical behavior of Nafion membranes with their microstructures and nanostructures as a function of electrolyte type. The influence of electrolytes of Li salts with different counteranions on the Nafion membranes was investigated in terms of hydration level, structure (using X‐ray diffraction and small angle X‐ray scattering), stress–strain characteristics, and electrochemical behavior (by cyclic voltammetery and electrochemical impedance spectroscopy). The effects of using ionic liquid (IL), as the electrolyte, addition of different supporting solvent and the addition of Li+ ions to water‐free IL‐soaked membranes on the structural and electrochemical properties of Nafion were examined. The nano‐ and microstructure of the Nafion changed considerably as a function of the identity of the electrolyte solution. The electrochemical behavior of the IL‐soaked samples was compared with that of the water‐soaked Li+‐exchanged Nafion. It was seen that the ionic conductivity of the Nafion membranes was reduced significantly when water was replaced by pure IL. Using the supporting solvents increased the conductivity of IL‐soaked Nafion membranes dramatically. The presence of a small amount of Li+ ions together with the IL ions caused a significant decrease in charge transfer resistance and increases in double layer capacitance and in ionic conductivity over that of the water‐free sample and also over water‐soaked Li+‐exchanged Nafion. These findings can be useful to improve the knowledge on Nafion's microstructure and also to improve the electromechanical behavior of Nafion‐based ionic polymer–metal composites actuators. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45239.
Understanding the Mechanisms of Gold Shell Growth onto Polymer Microcapsules to Control Shell Thickness
Authors: Tasker Alison L. , Hitchcock James , Baxter Elaine A. , Cayre Dr Olivier J. , Biggs Simon 
Published: May 2017

AbstractPolymer microcapsules have been used commercially for decades, however they have an inherent flaw which renders them impractical as a carrier of small, volatile molecules. The porous nature of the polymer shell allows for diffusion of the encapsulated molecules into the bulk. The use of metal shells is an innovative way to prevent undesired loss of small molecules from the core of microcapsules, however it is important, particularly when using expensive metals to ensure that the resulting shell is as thin as possible. Here we investigate the fundamental mechanisms controlling the gold shell thickness when a fragrance oil is encapsulated in a poly(methyl methacrylate) shell. We consider the distribution of the nanoparticles on the capsule surface, and from quantification of the adsorbed nanoparticle (NP) density and resulting shell thickness, we propose mechanisms to describe the gold shell growth for systems with high and low NP surface coverage. We suggest from our observations that the gold grows to fill in the gaps between NPs. At low NP concentrations, thicker metal shells form. We postulate that this is due to the low NP density on the surface, forcing the gold clusters to grow larger before they meet the adjacent ones. Thus, to grow the thinnest possible shells a densely packed monolayer of platinum nanoparticles is required on the capsule surface.
A pump‐free microfluidic 3D perfusion platform for the efficient differentiation of human hepatocyte‐like cells
Authors: Ong Louis Jun Ye , Chong Lor Huai , Jin Lin , Singh Pawan Kumar , Lee Poh Seng , Yu Hanry , Ananthanarayanan Abhishek , Leo Hwa Liang , Toh Yi‐Chin 
Published: May 2017

ABSTRACTThe practical application of microfluidic liver models for in vitro drug testing is partly hampered by their reliance on human primary hepatocytes, which are limited in number and have batch‐to‐batch variation. Human stem cell‐derived hepatocytes offer an attractive alternative cell source, although their 3D differentiation and maturation in a microfluidic platform have not yet been demonstrated. We develop a pump‐free microfluidic 3D perfusion platform to achieve long‐term and efficient differentiation of human liver progenitor cells into hepatocyte‐like cells (HLCs). The device contains a micropillar array to immobilize cells three‐dimensionally in a central cell culture compartment flanked by two side perfusion channels. Constant pump‐free medium perfusion is accomplished by controlling the differential heights of horizontally orientated inlet and outlet media reservoirs. Computational fluid dynamic simulation is used to estimate the hydrostatic pressure heads required to achieve different perfusion flow rates, which are experimentally validated by micro‐particle image velocimetry, as well as viability and functional assessments in a primary rat hepatocyte model. We perform on‐chip differentiation of HepaRG, a human bipotent progenitor cell, and discover that 3D microperfusion greatly enhances the hepatocyte differentiation efficiency over static 2D and 3D cultures. However, HepaRG progenitor cells are highly sensitive to the time‐point at which microperfusion is applied. Isolated HepaRG cells that are primed as static 3D spheroids before being subjected to microperfusion yield a significantly higher proportion of HLCs (92%) than direct microperfusion of isolated HepaRG cells (62%). This platform potentially offers a simple and efficient means to develop highly functional microfluidic liver models incorporating human stem cell‐derived HLCs. Biotechnol. Bioeng. 2017;114: 2360–2370. © 2017 Wiley Periodicals, Inc.
Modeling thrombus formation and growth
Authors: Hosseinzadegan Hamid , Tafti Danesh K. 
Published: May 2017

ABSTRACTThe paper reviews the state‐of‐the‐art in computational modeling of thrombus formation and growth and related phenomena including platelet margination, activation, adhesion, and embolization. Presently, there is a high degree of empiricism in the modeling of thrombus formation. Based on the experimentally observed physics, the review gives useful strategies for predicting thrombus formation and growth. These include determining blood components involved in atherosclerosis, effective blood viscosity, tissue properties, and methods proposed for boundary conditions. In addition to the guidelines, ongoing research on the effect of shear stress on platelet margination, activation and adhesion, and platelet‐surface interactions are reviewed. Biotechnol. Bioeng. 2017;114: 2154–2172. © 2017 Wiley Periodicals, Inc.
Hydrophilic interaction and reversed‐phase ultra‐performance liquid chromatography TOF‐MS for metabolomic analysis of Veratrum nigrum‐induced cardiotoxicity
Authors: Wei Ziheng , Dong Xu , Zhang Hanzhe , Gao Songyan , Shi Wei , Yang Feng , Dong Xin 
Published: May 2017

AbstractThe acute cardiotoxicity induced by Veratrum nigrum (VN) is explored by analyzing heart tissue metabolic profiles in mouse models and applying reversed‐phase liquid chromatography mass spectrometry and hydrophilic interaction liquid chromatography mass spectrometry that are based on ultra‐high‐performance liquid chromatography quadrupole time‐of‐flight mass spectrometry. An animal model of acute heart injury was established in mice via intra‐gastric administration of VN. Then, electrocardiogram and echocardiograph monitoring of cardiac function and pathological examination were performed on mice in both the control and VN groups, and it was verified that acute heart injury was caused. Meanwhile, comparing the results of the control and VN groups, we detected 36 differential endogenous metabolites of heart tissue, including taurine, riboflavin, purine and lipids, which are related to many possible pathways such as purine metabolism, taurine and hypotaurine metabolism and energy metabolism. Our study provides a scientific approach for evaluating and revealing the mechanisms of VN‐induced cardiotoxicity via the metabolomic strategy.
Topologically consistent leafy tree morphing
Authors: Wang Yutong , Wang Luyuan , Deng Zhigang , Jin Xiaogang 
Published: May 2017

AbstractWe present a novel morphing technique to generate pleasing visual effects between 2 topologically varying trees while preserving the topological consistency and botanical meanings of any in‐between shapes as natural trees. Specifically, we first efficiently convert leafy trees into botanically inspired chain‐lobe representations in an automatic way. With the aid of branching‐pattern aware, one‐to‐many correspondences between branches and leaves, we hierarchically interpolate branches of in‐between trees while maintaining their topological consistencies. Finally, we simultaneously interpolate foliage, specifically every single leaf, during the morphing process, avoiding the generation of unpleasant “floating” leaves. We demonstrate the effectiveness of our approach by creating visually compelling tree morphing animations, even between cross‐species.
Simulating collective transport of virtual ants
Authors: Guo Shihui , Wang Meili , Notman Gabriel , Chang Jian , Zhang Jianjun , Liao Minghong 
Published: May 2017

AbstractThis paper simulates the behaviour of collective transport where a group of ants transports an object in a cooperative fashion. Different from humans, the task coordination of collective transport, with ants, is not achieved by direct communication between group individuals, but through indirect information transmission via mechanical movements of the object. This paper proposes a stochastic probability model to model the decision‐making procedure of group individuals and trains a neural network via reinforcement learning to represent the force policy. Our method is scalable to different numbers of individuals and is adaptable to users' input, including transport trajectory, object shape, external intervention, etc. Our method can reproduce the characteristic strategies of ants, such as realign and reposition. The simulations show that with the strategy of reposition, the ants can avoid deadlock scenarios during the task of collective transport.
Chest closure after rib‐cross thoracotomy for descending and thoracoabdominal aortic aneurysm repair
Authors: Uehara Kyokun , Matsuda Hitoshi , Minatoya Kenji , Kobayashi Junjiro 
Published: May 2017

Key Clinical MessageThe fixation system consisting of a titanium plate and three pairs of claws can fix the ribs externally. This may contribute to preserve the normal thoracic structure and could result in a significant reduction in the period of ventilator dependency.
Gold Doping in PtCu3/HSAC Nanoparticles and Their Morphological, Structural, and Compositional Changes during Oxygen Reduction Reaction Electrochemical Cycling
Authors: Ruiz‐Zepeda Francisco , Gatalo Matija , Jovanovič Primož , Pavlišič Andraž , Bele Marjan , Hodnik Nejc , Gaberšček Miran 
Published: May 2017

AbstractPt‐based nanoparticles supported on high‐surface‐area carbon (HSAC) show very good properties as catalysts in polymer electrolyte membrane fuel cells (PEMFC). In many cases, however, the initial high activity of such catalysts rapidly drops as caused by various detrimental phenomena occurring in a typical electrochemical environment. In this work, a detailed study of a highly active system composed of PtCu3/HSAC nanoparticles with partially ordered structure and Pt skin with the addition of Au is performed. By using aberration‐corrected scanning transmission electron microscopy, the effects of adding small amounts of gold compared to the nonmodified sample are followed through the different stages of an electrochemical cycling degradation protocol. Various morphological changes such as faceting, reshaping, and thickening of the Pt skin are investigated for both sets of samples on the atomic level. Interesting features such as well‐defined shapes and surface defects are observed after degradation. However, the most important differences in terms of durability seem related to particle porosity. Finally, the experimental morphological observations are successfully reproduced by dealloying simulation with kinetic Monte Carlo modeling.
Nickel‐Iron Alloy Nanoparticle‐Decorated K2NiF4‐Type Oxide as an Efficient and Sulfur‐Tolerant Anode for Solid Oxide Fuel Cells
Authors: Wu Nuo , Wang Wei , Zhong Yijun , Yang Guangming , Qu Jifa , Shao Zongping 
Published: May 2017

AbstractWe report a new nickel‐iron alloy nanoparticle‐decorated LaSrFe0.75Ni0.25O4 K2NiF4‐type oxide with Ruddlesden‐Popper structure (RP‐LSFN), which performed as a high‐performance sulfur‐resistant anode prepared by using an infiltration method for solid oxide fuel cells (SOFCs) with LaSrFeNiO6‐δ double perovskite (DP‐LSFN) as the precursor. A reduction converts the DP‐LSFN phase into mixed phases containing the RP‐LSFN and FeNi3 nanoparticles. The morphology, thermal expansion behavior, sulfur tolerance, and electrochemical activity for hydrogen oxidation of this FeNi3 nanoparticle‐decorated, RP‐LSFN‐infiltrated anode are investigated. An electrolyte‐supported SOFC with this infiltrated anode generates a high power output of 541 mW cm−2 at 800 °C operated with 1000 ppm H2S−H2 as the fuel, which compares favorably to that with pure H2 fuel. A single cell with this anode demonstrates favorable stability at 800 °C during 90, 40, and 20 h operation with H2 containing 100, 200, and 1000 ppm H2S, respectively.
AcetylacetonateBODIPY‐Biscyclometalated Iridium(III) Complexes: Effective Strategy towards Smarter Fluorescent Photosensitizer Agents
Authors: Palao Eduardo , Sola‐Llano Rebeca , Tabero Andrea , Manzano Hegoi , Agarrabeitia Antonia R. , Villanueva Angeles , López‐Arbeloa Iñigo , Martínez‐Martínez Virginia , Ortiz Maria J. 
Published: May 2017

AbstractBiscyclometalated IrIII complexes involving boron‐dipyrromethene (BODIPY)‐based ancillary ligands, where the BODIPY unit is grafted to different chelating cores (acetylacetonate for Ir‐1 and Ir‐2, and bipyridine for Ir‐3) by the BODIPY meso position, have been synthesized and characterized. Complexes with the BODIPY moiety directly grafted to acetylacetonate (Ir‐1 and Ir‐2) exhibit higher absorption coefficients (ϵ≈4.46×104 m−1 cm−1 and 3.38×104 m−1 cm−1 at 517 nm and 594 nm, respectively), higher moderate fluorescence emission (φfl≈0.08 and 0.22 at 528 nm and 652 nm, respectively) and, in particular, more efficient singlet oxygen generation upon visible‐light irradiation (φΔ≈0.86 and 0.59, respectively) than that exhibited by Ir‐3 (φΔ≈0.51, but only under UV light). Phosphorescence emission, nanosecond time‐resolved transient absorption, and DFT calculations suggest that BODIPY‐localized long‐lived 3IL states are populated for Ir‐1 and Ir‐2. In vitro photodynamic therapy (PDT) activity studied for Ir‐1 and Ir‐2 in HeLa cells shows that such complexes are efficiently internalized into the cells, exhibiting low dark‐ and high photocytoxicity, even at significantly low complex concentration, making them potentially suitable as theranostic agents.
Universal Method for Large‐Scale Synthesis of Layered Transition Metal Dichalcogenides
Authors: Sofer Zdeněk , Sedmidubský David , Luxa Jan , Bouša Daniel , Huber Štěpán , Lazar Petr , Veselý Martin , Pumera Martin 
Published: May 2017

AbstractThe layered transition metal dichalcogenides are currently amongst the most intensively investigated materials. These compounds constitute a broad family of materials, with characteristic layered structures, covering both semiconductors and metallic materials. The great attention arises from the possibility to exfoliate these materials down to single layers with many unique properties, such as thickness dependent band‐gap energy, and the possibility of tuning transport properties by phase transitions. The research in the field of transition metal dichalcogenides is also motivated by their high electrocatalytic activity towards several industrially important reactions, such as the hydrogen evolution reaction, as well as many other applications in nano‐ and optoelectronics. Although these materials are studied intensively, their availability is extremely limited and only disulfides of molybdenum and tungsten are broadly commercially available. Here an optimized procedure for simple direct synthesis of transition metal dichalcogenides using powder metals and elemental chalcogens is reported. The optimized thermal treatment allowed the synthesis scaling of the sulfides, selenides and tellurides of 4th, 5th, 6th, and 7th group of layered‐structure dichalcogenides. The synthesized transition metal dichalcogenides were single phase. The phase purity, structure, and morphology were investigated in detail by electron microscopy and EDS, X‐ray diffraction, and Raman spectroscopy.
Study of retinal neurodegeneration and maculopathy in diabetic Meriones shawi: A particular animal model with human‐like macula
Authors: Hammoum Imane , Benlarbi Maha , Dellaa Ahmed , Szabó Klaudia , Dékány Bulcsú , Csaba Dávid , Almási Zsuzsanna , Hajdú Rozina I. , Azaiz Rached , Charfeddine Ridha , Lukáts Ákos , Ben Chaouacha‐Chekir Rafika 
Published: May 2017

AbstractThe purpose of this work was to evaluate a potentially useful animal model, Meriones shawi (M.sh)—developing metabolic X syndrome, diabetes and possessing a visual streak similar to human macula—in the study of diabetic retinopathy and diabetic macular edema (DME). Type 2 diabetes (T2D) was induced by high fat diet administration in M.sh. Body weights, blood glucose levels were monitored throughout the study. Diabetic retinal histopathology was evaluated 3 and 7 months after diabetes induction. Retinal thickness was measured, retinal cell types were labeled by immunohistochemistry and the number of stained elements were quantified. Apoptosis was determined with TUNEL assay. T2D induced progressive changes in retinal histology. A significant decrease of retinal thickness and glial reactivity was observed without an increase in apoptosis rate. Photoreceptor outer segment degeneration was evident, with a significant decrease in the number of all cones and M‐cone subtype, but—surprisingly—an increase in S‐cones. Damage of the pigment epithelium was also confirmed. A decrease in the number and labeling intensity of parvalbumin‐ and calretinin‐positive amacrine cells and a loss of ganglion cells was detected. Other cell types showed no evident alterations. No DME‐like condition was noticed even after 7 months. M.sh could be a useful model to study the evolution of diabetic retinal pathology and to identify the role of hypertension and dyslipidemia in the development of the reported alterations. Longer follow up would be needed to evaluate the potential use of the visual streak in modeling human macular diseases.