bluuebunny/crossref_metadata_2025 huggingface dataset:
Eine Mischung deuteriummarkierter Silane als einfache mechanistische Sonde, die ohne Bestimmung von absoluten Konfigurationen auskommt
Authors: Fallon Thomas , Oestreich Martin
Published: March 2015

Es wird über die Synthese und den Einsatz einer neuen stereochemischen Sonde für Mechanismen am Siliciumatom eines deuteriummarkierten Silolans berichtet. Der zentrale Syntheseschritt ist die Hydrierung eines 2,5‐Dihydrosilols mit Deuteriumgas, was zu einer komplexen Mischung isochroner Stereoisotopologe führt. Das gesamte stereochemische Ungleichgewicht dieser Mischung ist aus ihrem 2H‐NMR‐Spektrum ersichtlich, und das bietet ein gutes qualitatives Maß für Konfigurationsänderungen am Siliciumatom. Das Verfahren ist schnell, benutzerfreundlich und überwindet die Einschränkungen und Nebeneffekte klassischer Methoden. Die Nützlichkeit dieses neuen Instruments zum Verfolgen des stereochemischen Verlaufs von Bindungsknüpfungen am Siliciumatom wird anhand etlicher klassischer Reaktionen sowie aktueller katalytischer Umsetzungen veranschaulicht.
Strained Cyclooctyne as a Molecular Platform for Construction of Multimodal Imaging Probes
Authors: Sun Yao , Ma Xiaowei , Cheng Kai , Wu Biying , Duan Jianli , Chen Hao , Bu Lihong , Zhang Ruiping , Hu Xianming , Deng Zixin , Xing Lei , Hong Xuechuan , Cheng Zhen
Published: March 2015

Small‐molecule‐based multimodal and multifunctional imaging probes play prominent roles in biomedical research and have high clinical translation ability. A novel multimodal imaging platform using base‐catalyzed double addition of thiols to a strained internal alkyne such as bicyclo[6.1.0]nonyne has been established in this study, thus allowing highly selective assembly of various functional units in a protecting‐group‐free manner. Using this molecular platform, novel dual‐modality (PET and NIRF) uPAR‐targeted imaging probe: 64Cu‐CHS1 was prepared and evaluated in U87MG cells and tumor‐bearing mice models. The excellent PET/NIRF imaging characteristics such as good tumor uptake (3.69 %ID/g at 2 h post‐injection), high tumor contrast, and specificity were achieved in the small‐animal models. These attractive imaging properties make 64Cu‐CHS1 a promising probe for clinical use.
SBA‐15‐Oxynitrides as a Solid‐Base Catalyst: Effect of Nitridation Temperature on Catalytic Activity
Authors: Singh Baljeet , Mote Kaustubh R. , Gopinath C. S. , Madhu P. K. , Polshettiwar Vivek
Published: March 2015

Solid bases, such as SBA‐15‐oxynitrides, have attracted considerable interest for potential applications as catalysts in important industrial processes. Reported herein is that by simply tuning the temperature of nitridation (ammonolysis), the catalytic activity of these solid bases can be enhanced. Solid‐state NMR spectroscopy and XPS studies provided the reasoning behind this change in activity.
In Situ Generation of Difluoromethyl Diazomethane for [3+2] Cycloadditions with Alkynes
Authors: Mykhailiuk Pavel K.
Published: March 2015

A novel approach to agrochemically important difluoromethyl‐substituted pyrazoles has been developed based on the elusive reagent CF2HCHN2, which was synthesized (generated in situ) for the first time and employed in [3+2] cycloaddition reactions with alkynes. The reaction is extremely practical as it is a one‐pot process, does not require a catalyst or the isolation of the potentially toxic and explosive gaseous intermediate, and proceeds in a common solvent, namely chloroform, in air. The reaction is also scalable and allows for the preparation of the target pyrazoles on gram scale.
Nickel‐Rich Layered Lithium Transition‐Metal Oxide for High‐Energy Lithium‐Ion Batteries
Authors: Liu Wen , Oh Pilgun , Liu Xien , Lee Min‐Joon , Cho Woongrae , Chae Sujong , Kim Youngsik , Cho Jaephil
Published: March 2015

High energy‐density lithium‐ion batteries are in demand for portable electronic devices and electrical vehicles. Since the energy density of the batteries relies heavily on the cathode material used, major research efforts have been made to develop alternative cathode materials with a higher degree of lithium utilization and specific energy density. In particular, layered, Ni‐rich, lithium transition‐metal oxides can deliver higher capacity at lower cost than the conventional LiCoO2. However, for these Ni‐rich compounds there are still several problems associated with their cycle life, thermal stability, and safety. Herein the performance enhancement of Ni‐rich cathode materials through structure tuning or interface engineering is summarized. The underlying mechanisms and remaining challenges will also be discussed.
Development of Chiral Sulfoxide Ligands for Asymmetric Catalysis
Authors: Trost Barry M. , Rao Meera
Published: March 2015

Nitrogen‐, phosphorus‐, and oxygen‐based ligands with chiral backbones have been the historic workhorses of asymmetric transition‐metal‐catalyzed reactions. On the contrary, sulfoxides containing chirality at the sulfur atom have mainly been used as chiral auxiliaries for diastereoselective reactions. Despite several distinct advantages over traditional ligand scaffolds, such as the proximity of the chiral information to the metal center and the ability to switch between S and O coordination, these compounds have only recently emerged as a versatile class of chiral ligands. In this Review, we detail the history of the development of chiral sulfoxide ligands for asymmetric catalysis. We also provide brief descriptions of metal–sulfoxide bonding and strategies for the synthesis of enantiopure sulfoxides. Finally, insights into the future development of this underutilized ligand class are discussed.
Air‐Stable (CAAC)CuCl and (CAAC)CuBH4 Complexes as Catalysts for the Hydrolytic Dehydrogenation of BH3NH3
Authors: Hu Xingbang , Soleilhavoup Michèle , Melaimi Mohand , Chu Jiaxiang , Bertrand Guy
Published: March 2015

The first stable copper borohydride complex [(CAAC)CuBH4] [CAAC=cyclic(alkyl)(amino)carbene] bearing a single monodentate ligand was prepared by addition of NaBH4 or BH3NH3 to the corresponding [(CAAC)CuCl] complex. Both complexes are air‐stable and promote the catalytic hydrolytic dehydrogenation of ammonia borane. The amount of hydrogen released reaches 2.8 H2/BH3NH3 with a turnover frequency of 8400 mol molcat−1 h−1 at 25 °C. In a fifteen‐cycle experiment, the catalyst was reused without any loss of efficiency.
Mannose‐6‐Phosphate Receptor: A Target for Theranostics of Prostate Cancer
Authors: Vaillant Ophélie , Cheikh Khaled El , Warther David , Brevet David , Maynadier Marie , Bouffard Elise , Salgues Frédéric , Jeanjean Audrey , Puche Pierre , Mazerolles Catherine , Maillard Philippe , Mongin Olivier , Blanchard‐Desce Mireille , Raehm Laurence , Rébillard Xavier , Durand Jean‐Olivier , Gary‐Bobo Magali , Morère Alain , Garcia Marcel
Published: March 2015

The development of personalized and non‐invasive cancer therapies based on new targets combined with nanodevices is a major challenge in nanomedicine. In this work, the over‐expression of a membrane lectin, the cation‐independent mannose 6‐phosphate receptor (M6PR), was specifically demonstrated in prostate cancer cell lines and tissues. To efficiently target this lectin a mannose‐6‐phosphate analogue was synthesized in six steps and grafted onto the surface of functionalized mesoporous silica nanoparticles (MSNs). These MSNs were used for in vitro and ex vivo photodynamic therapy to treat prostate cancer cell lines and primary cell cultures prepared from patient biopsies. The results demonstrated the efficiency of M6PR targeting for prostate cancer theranostic.
Controlling the Origins of Inflammation with a Photoactive Lipopeptide Immunopotentiator
Authors: Mancini Rock J. , Stutts Lalisa , Moore Troy , Esser‐Kahn Aaron P.
Published: March 2015

Inflammatory immune responses are mediated by signaling molecules that are both produced by and recognized across highly heterogeneous cell populations. As such, the study of inflammation using traditional immunostimulants is complicated by paracrine and autocrine signaling, which obscures the origin of a propagating response. To address this challenge, we developed a small‐molecule probe that can photosensitize immune cells, thus allowing light‐mediated inflammation. This probe was used to control the origin of inflammation using light. Following this motif, inflammation was initiated from fibroblasts or dendritic cells. The contributions of fibroblasts and dendritic cells in initiating inflammation in heterogeneous co‐culture are reported, thus providing insights into the future development of vaccines and treatment of inflammation.
Crystalline Capsules: Metal–Organic Frameworks Locked by Size‐Matching Ligand Bolts
Authors: Wang Hao , Xu Jian , Zhang Da‐Shuai , Chen Qiang , Wen Rong‐Mei , Chang Ze , Bu Xian‐He
Published: March 2015

Metal–organic frameworks (MOFs) are shown to be good examples of a new class of crystalline porous materials for guest encapsulation. Since the encapsulation/release of guest molecules in MOF hosts is a reversible process in nature, how to prevent the leaching of guests from the open pores with minimal and nondestructive modifications of the structure is a critical issue. To address this issue, we herein propose a novel strategy of encapsulating guests by introducing size‐matching organic ligands as bolts to lock the pores of the MOFs through deliberately anchoring onto the open metal sites in the pores. Our proposed strategy provides a mechanical way to prevent the leaching of guests and thereby has less dependence on the specific chemical environment of the hosts, thus making it applicable for a wide variety of existing MOFs once the size‐matching ligands are employed.
A Constellation of Deuterium‐Labeled Silanes as a Simple Mechanistic Probe not Requiring Absolute Configuration Determination
Authors: Fallon Thomas , Oestreich Martin
Published: March 2015

A new stereochemical probe for mechanisms at the silicon atom that is based on a deuterium‐labeled silolane is synthesized and evaluated. The key synthetic step involves the hydrogenation of a 2,5‐dihydrosilole with deuterium gas, giving a complex mixture of isochronic stereoisotopologues. The overall stereochemical imbalance of this mixture is evident in its 2H NMR spectrum, which provides a good qualitative measure of changes in the configuration at the silicon atom. The technique is rapid, easy to use, and overcomes limitations and biases of traditional methods. The utility of this new procedure is demonstrated by tracking the stereochemical course of several classical reactions as well as contemporary catalytic transformations involving bond formation at the silicon atom.
Alkyl Aryl Ether Bond Formation with PhenoFluor
Authors: Shen Xiao , Neumann Constanze N. , Kleinlein Claudia , Goldberg Nathaniel W. , Ritter Tobias
Published: March 2015

An alkyl aryl ether bond formation reaction between phenols and primary and secondary alcohols with PhenoFluor has been developed. The reaction features a broad substrate scope and tolerates many functional groups, and substrates that are challenging for more conventional ether bond forming processes may be coupled. A preliminary mechanistic study indicates reactivity distinct from conventional ether bond formation.
A Stable but Highly Reactive Phosphine‐Coordinated Borenium: Metal‐free Dihydrogen Activation and Alkyne 1,2‐Carboboration
Authors: Devillard Marc , Brousses Rémy , Miqueu Karinne , Bouhadir Ghenwa , Bourissou Didier
Published: March 2015

Borenium cations have been found to be valuable analogues of boranes as a result of their cationic character which imparts high electrophilicity. Herein, we report the synthesis, characterization, and reactivity of a new type of borenium cation employing a naphthyl bridge and a strong intramolecular P→B interaction. The cation reacts with H2 in the presence of PtBu3 (frustrated Lewis pair (FLP) approach) but also on its own. The mechanism of the reaction between the borenium cation and H2 in the absence of PtBu3 has been investigated using deuterium‐labeling experiments and DFT calculations. Both experiments and calculations imply the side‐on coordination of H2 to the B center, followed by heterolytic splitting and BC bond cleavage. An uncommon syn 1,2‐carboboration has also been observed upon reaction of the borenium ion with 3‐hexyne.
Widening Synthesis Bottlenecks: Realization of Ultrafast and Continuous‐Flow Synthesis of High‐Silica Zeolite SSZ‐13 for NOx Removal
Authors: Liu Zhendong , Wakihara Toru , Oshima Kazunori , Nishioka Daisuke , Hotta Yuusuke , Elangovan Shanmugam P. , Yanaba Yutaka , Yoshikawa Takeshi , Chaikittisilp Watcharop , Matsuo Takeshi , Takewaki Takahiko , Okubo Tatsuya
Published: March 2015

Characteristics of zeolite formation, such as being kinetically slow and thermodynamically metastable, are the main bottlenecks that obstruct a fast zeolite synthesis. We present an ultrafast route, the first of its kind, to synthesize high‐silica zeolite SSZ‐13 in 10 min, instead of the several days usually required. Fast heating in a tubular reactor helps avoid thermal lag, and the synergistic effect of addition of a SSZ‐13 seed, choice of the proper aluminum source, and employment of high temperature prompted the crystallization. Thanks to the ultra‐short period of synthesis, we established a continuous‐flow preparation of SSZ‐13. The fast‐synthesized SSZ‐13, after copper‐ion exchange, exhibits outstanding performance in the ammonia selective catalytic reduction (NH3‐SCR) of nitrogen oxides (NOx), showing it to be a superior catalyst for NOx removal. Our results indicate that the formation of high‐silica zeolites can be extremely fast if bottlenecks are effectively widened.
Studies on synthesis of quinonylidene Hoveyda‐type complexes
Authors: Grudzień Krzysztof , Barbasiewicz Michał
Published: March 2015

In a quest of redox‐switchable metathesis catalysts we attempted synthesis of ruthenium quinonylidene complexes using two synthetic pathways. First, Hoveyda‐type complexes bearing chelating benzylidene and naphthylidene ligands substituted with two alkoxy/hydroxy groups were synthesized and characterized. The catalysts were tested in model ring‐closing metathesis reactions, and displayed interesting correlations between structure and catalytic activity. Unfortunately, numerous attempts at oxidation of the complexes to derivatives of benzo‐ and naphthoquinone were unsuccessful. However, the second approach, using exchange reaction of ruthenium precursor with vinylquinone ligand, gave a transient unstable product observed with 1H NMR. The experimental data suggest that conjugation of electron‐deficient quinones to the ruthenium centre results in intrinsically unstable species, which undergo secondary reactions under ambient conditions. Copyright © 2015 John Wiley & Sons, Ltd.
Enhanced endothelial progenitor cell mobilization and function through direct manipulation of hypoxia inducible factor‐1α
Authors: Zan Tao , Li Hua , Du Zijing , Gu Bin , Liu Kai , Li Qingfeng
Published: March 2015

Endothelial progenitor cells (EPCs) play a significant role in physiological and pathological hypoxia resistance and neovascularization processes. The ability to mobilize EPCs from bone marrow usually indicates a prognostic endpoint of several vascular diseases. Thus, it is of great value to study possible approaches for activating functional EPCs. The mobilization/homing of EPCs from bone marrow is signalled by stromal‐derived factor‐1 (SDF‐1), which is regulated by the hypoxia‐inducible factor‐1α (HIF‐1α). This study investigated the effects of directly manipulating HIF‐1α on human EPCs in vitro. EPCs were isolated from human umbilical cord blood. Lentiviral vectors carrying HIF‐1α and shRNA targeting HIF‐1α were constructed for gene modification of the EPCs. Results demonstrated that after overexpression of HIF‐1α by lentiviral transfection, the proliferative capacity of EPCs was elevated while the apoptosis was inhibited and vice versa. On the other hand, the expression of angiogenic‐related cytokines including SDF‐1 was upregulated on both gene and protein levels when EPCs were transfected with HIF‐1α. These results indicate that direct HIF‐1α manipulation over human EPCs is an effective method to promote EPC function and mobilization, thus suggest that drugs or reagents that elevate HIF‐1α expression are capable of treating ischemic diseases. Copyright © 2015 John Wiley & Sons, Ltd.
MnO QD/Graphene Dot Fabrics: A Versatile Nanohybrid Material
Authors: Su Liwei , Jiang Jiajia , Wang Lianbang , Wang Yuanhao , Ren Manman
Published: March 2015

Quantum dots (QDs) are attracting tremendous interests due to their small size and subsequently various unique physical/chemical merits, especially incorporating with graphene nanosheets (GNS). Up to now, it is significant but still a big challenge to exploit a facile and good‐adaptability method to prepare QDs/GNS nanohybrids. In this work, a gel‐like film (GF) mechanism was proposed for the first time, with easy operation, low cost, and universal applications in particular. By this route, millions of MnO QDs were homogeneously dispersed on the GNS surface, very similar to the dot fabric in real life, and presented superior long‐term and rate performances for lithium storage benefiting from the positive effect of QDs and GNS. The reversible capacity after 80 cycles was 766.8 mAh g−1, still higher than the theoretical value of MnO. More importantly, this GF method has universal adaptability for several types of MO (where M=Mn, Co, Fe, Ni) QDs/GNS nanohybrids. This work may disclose new ways in understanding the formation of QDs/GNS and enlighten us on developing brilliant materials for powerful devices and electrochemical catalysts.
Unilamellar Vesicles from Amphiphilic Graphene Quantum Dots
Authors: Nandi Sukhendu , Kolusheva Sofiya , Malishev Ravit , Trachtenberg Alexander , Vinod T. P. , Jelinek Raz
Published: March 2015

Graphene quantum dots (GQDs) have attracted considerable interest due to their unique physicochemical properties and various applications. For the first time it is shown that GQDs surface‐functionalized with hydrocarbon chains (i.e., amphiphilic GQDs) self‐assemble into unilamellar spherical vesicles in aqueous solution. The amphiphilic GQD vesicles exhibit multicolor luminescence that can be readily exploited for membrane studies by fluorescence spectroscopy and microscopy. The GQD vesicles were used for microscopic analysis of membrane interactions and disruption by the peptide beta‐amyloid.
The Mechanism of CO2 Insertion into Iridium(I) Hydroxide and Alkoxide Bonds: A Kinetics and Computational Study
Authors: Truscott Byron J. , Kruger Hedi , Webb Paul B. , Bühl Michael , Nolan Steven P.
Published: March 2015

The facile insertion of CO2 into iridium(I) hydroxide, alkoxide, and amide bonds was recently reported. In particular, [Ir(cod)(IiPr)(OH)] (IiPr=1,3‐bis(isopropyl)imidazol‐2‐ylidene) reacted with CO2 in solution and in the solid state in a matter of minutes to give the novel [{Ir(cod)(IiPr)}2(μ‐κ1O:κ2O,O‐CO3)] complex. In the present study, this reaction is probed using kinetics and theoretical studies, which enabled us to analyse its facile nature and to fully elucidate the reaction mechanism with excellent correlation between the two methods.
Modular Stereoselective Synthesis of (1→2)‐C‐Glycosides based on the sp2–sp3 Suzuki–Miyaura Reaction
Authors: Oroszova Beata , Choutka Jan , Pohl Radek , Parkan Kamil
Published: March 2015

This work reports a modular and rapid approach to the stereoselective synthesis of a variety of α‐ and β‐(1→2)‐linked C‐disaccharides. The key step is a Ni‐catalyzed cross‐coupling reaction of D‐glucal pinacol boronate with alkyl halide glycoside easily prepared from commercially available D‐glucal. The products of this sp2–sp3 cross‐coupling reaction can be converted to glucopyranosyl, mannopyranosyl, or 2‐deoxy‐glucopyranosyl C‐mannopyranosides by one‐ or two‐step stereoselective oxidative–reductive transformations. To the best of our knowledge, we demonstrated the first synthetic application of a challenging sp2–sp3 Suzuki‐Miyaura cross‐coupling reaction in carbohydrate chemistry.
Non‐Aqueous Sol–Gel Synthesis of Ultra Small Persistent Luminescence Nanoparticles for Near‐Infrared In Vivo Imaging
Authors: Teston Eliott , Richard Sophie , Maldiney Thomas , Lièvre Nicole , Wang Guillaume Yangshu , Motte Laurence , Richard Cyrille , Lalatonne Yoann
Published: March 2015

Ultra‐small ZnGa2O4:Cr3+ nanoparticles (6 nm) that exhibit near‐infrared (NIR) persistent luminescence properties are synthesized by using a non‐aqueous sol–gel method assisted by microwave irradiation. The nanoparticles are pegylated, leading to highly stable dispersions under physiological conditions. Preliminary in vivo studies show the high potential for these ultra‐small ZnGa2O4:Cr3+ nanoparticles to be used as in vivo optical nanotools as they emit without the need for in situ excitation and, thus, avoid the autofluorescence of tissues.
MnO2 Nanosheets Grown on Nitrogen‐Doped Hollow Carbon Shells as a High‐Performance Electrode for Asymmetric Supercapacitors
Authors: Li Lei , Li Rumin , Gai Shili , Ding Shujiang , He Fei , Zhang Milin , Yang Piaoping
Published: March 2015

A hierarchical hollow hybrid composite, namely, MnO2 nanosheets grown on nitrogen‐doped hollow carbon shells (NHCSs@MnO2), was synthesized by a facile in situ growth process followed by calcination. The composite has a high surface area (251 m2g−1) and mesopores (4.5 nm in diameter), which can efficiently facilitate transport during electrochemical cycling. Owing to the synergistic effect of NHCSs and MnO2, the composite shows a high specific capacitance of 306 F g−1, good rate capability, and an excellent cycling stability of 95.2 % after 5000 cycles at a high current density of 8 A g−1. More importantly, an asymmetric supercapacitor (ASC) assembled by using NHCSs@MnO2 and activated carbon as the positive and negative electrodes exhibits high specific capacitance (105.5 F g−1 at 0.5 A g−1 and 78.5 F g−1 at 10 A g−1) with excellent rate capability, achieves a maximum energy density of 43.9 Wh kg−1 at a power density of 408 W kg−1, and has high stability, whereby the ASC retains 81.4 % of its initial capacitance at a current density of 5 A g−1 after 4000 cycles. Therefore, the NHCSs@MnO2 electrode material is a promising candidate for future energy‐storage systems.
Computational Mechanistic Elucidation of the Intramolecular Aminoalkene Hydroamination Catalysed by Iminoanilide Alkaline‐Earth Compounds
Authors: Tobisch Sven
Published: March 2015

A comprehensive computational exploration of plausible alternative mechanistic pathways for the intramolecular hydroamination (HA) of aminoalkenes by a recently reported class of kinetically stabilised iminoanilide alkaline‐earth silylamido compounds [{N^N}Ae{N(SiMe3)2}⋅(thf)n] ({N^N}=iminoanilide; Ae=Ca, Sr, Ba) is presented. On the one hand, a proton‐assisted concerted NC/CH bond‐forming pathway to afford the cycloamine in a single step can be invoked and on the other hand, a stepwise σ‐insertive pathway that involves a fast, reversible migratory olefin 1,2‐insertion step linked to a less rapid, irreversible metalC azacycle tether σ‐bond aminolysis. Notably, these alternative mechanistic avenues are equally consistent with reported key experimental features. The present study, which employs a thoroughly benchmarked and reliable DFT methodology, supports the prevailing mechanism to be a stepwise σ‐insertive pathway that sees an initial conversion of the {N^N}Ae silylamido into the catalytically competent {N^N}Ae amidoalkene compound and involves thereafter facile and reversible insertive NC bond‐forming ring closure, linked to irreversible intramolecular AeC tether σ‐bond aminolysis at the transient {N^N}Ae alkyl intermediate. Turnover‐limiting protonolysis accounts for the substantial primary kinetic isotope effect observed; its DFT‐derived barrier satisfactorily matches the empirically determined Eyring parameter and predicts the decrease in rate observed across the series Ca>Sr>Ba correctly. Non‐competitive kinetic demands militate against the operation of the concerted proton‐assisted pathway, which describes NC bond‐forming ring closure triggered by concomitant amino proton delivery at the CC linkage evolving through a multi‐centre TS structure. Valuable insights into the catalytic structure–activity relationships are unveiled by a detailed comparison of [{N^N}Ae(NHR)] catalysts. Moreover, the intriguingly opposite trends in reactivity observed in intramolecular (Ca>Sr>Ba) and intermolecular (Ca<Sr<Ba) HA catalysis for the studied family of iminoanilide alkaline‐earth amido catalysts are rationalised.
Biomolecular Assemblies Combining Two Orthogonal Copper‐Mediated Ligations in a One‐Pot Reaction
Authors: Grassin Adrien , Claron Michaël , Boturyn Didier
Published: March 2015

The access to multifunctional biomolecular compounds involves multistep reactions usually with a complicated protection scheme and lengthy separation processes. The development of a strategy combining several orthogonal ligations is highly desirable. Herein, we introduce a new method that involves two orthogonal copper‐mediated ligations of azide with alkyne, and amine with thioacid. We established compatible conditions to carry out molecular assemblies of three different chemical components in a single one‐pot reaction. The effectiveness of the method was demonstrated in the synthesis of biomolecular compounds that are known to target tumor tissue. The simple reaction conditions suggest that this strategy of combining several orthogonal ligations could have wide potential for the chemical synthesis of complex macromolecules.
Stabilization of a Bimolecular Triplex by 3′‐S‐Phosphorothiolate Modifications: An NMR and UV Thermal Melting Investigation
Authors: Evans Kathryn , Bhamra Inder , Wheelhouse Richard T. , Arnold John R. P. , Cosstick Richard , Fisher Julie
Published: March 2015

Triplexes formed from oligonucleic acids are key to a number of biological processes. They have attracted attention as molecular biology tools and as a result of their relevance in novel therapeutic strategies. The recognition properties of single‐stranded nucleic acids are also relevant in third‐strand binding. Thus, there has been considerable activity in generating such moieties, referred to as triplex forming oligonucleotides (TFOs). Triplexes, composed of Watson–Crick (W–C) base‐paired DNA duplexes and a Hoogsteen base‐paired RNA strand, are reported to be more thermodynamically stable than those in which the third strand is DNA. Consequently, synthetic efforts have been focused on developing TFOs with RNA‐like structural properties. Here, the structural and stability studies of such a TFO, composed of deoxynucleic acids, but with 3′‐S‐phosphorothiolate (3′‐SP) linkages at two sites is described. The modification results in an increase in triplex melting temperature as determined by UV absorption measurements.1H NMR analysis and structure generation for the (hairpin) duplex component and the native and modified triplexes revealed that the double helix is not significantly altered by the major groove binding of either TFO. However, the triplex involving the 3′‐SP modifications is more compact. The 3′‐SP modification was previously shown to stabilise G‐quadruplex and i‐motif structures and therefore is now proposed as a generic solution to stabilising multi‐stranded DNA structures.
Mesoporous Carbon Nitride‐Tungsten Oxide Composites for Enhanced Photocatalytic Hydrogen Evolution
Authors: Kailasam Kamalakannan , Fischer Anna , Zhang Guigang , Zhang Jinshui , Schwarze Michael , Schröder Marc , Wang Xinchen , Schomäcker Reinhard , Thomas Arne
Published: March 2015

Composites of mesoporous polymeric carbon nitride and tungsten(VI) oxide show very high photocatalytic activity for the evolution of hydrogen from water under visible light and in the presence of sacrificial electron donors. Already addition of very small amounts of WO3 yields up to a twofold increase in the efficiency when compared to bulk carbon nitrides and their composites and more notably even to the best reported mesoporous carbon nitride‐based photocatalytic materials. The higher activity can be attributed to the high surface area and synergetic effect of the carbon nitrides and the WO3 resulting in improved charge separation through a photocatalytic solid‐state Z‐scheme mechanism.
Rule Construction and Execution for Root Cause Analysis
Authors: Kudo Yutaka , Morimura Tomohiro , Sugauchi Kiminori , Masuishi Tetsuya , Komoda Norihisa
Published: March 2015

We developed a root cause analysis (RCA) system for an enterprise IT system environment. In this paper, we propose a rule‐construction method that builds analysis rule data objects from general analysis rules and the topology information of the actual target IT environment. Using this method, the IT administrator can use the RCA system without any manual rule modifications. For the execution of the analysis, we introduce the certainty factor to realize robust analysis when the order and reachability of a fault event cannot be guaranteed.
Stabilization of Power Supply for the Shinkansen with Power Converters
Authors: KUNOMURA KEN , YOKOSUKA MORIYUKI , ARAI SEIICHI , KUBOTA TOMOYA
Published: March 2015

In the Tokaido Shinkansen, rolling stock types have been unified as an inverter controlled type, which was introduced after Series 300. As a result, the input power factor of the main converter used in the rolling stock has been controlled to 1. In accordance with this change, the role of reactive compensation of static var compensators (SVC) has shifted from the load power of trains to the power consumed by the reactance in the electrical power system. Therefore, when taking into consideration the aging of power converters, it is time to reassess their layout and the configuration for the future of the Tokaido Shinkansen. We reassessed the equipment configuration, capacity, and layout of power converters and verified the impact on the stabilization of the power supply when introducing self‐commutated power converters.
Direct Determination of Trace Dopamine in an Ascorbic Acid Solution at a Bare Glassy Carbon Electrode Using Differential Pulse Voltammetry
Authors: Sun Lijian , Chen Jing , Zhao Fangmin , Liu Na , Zhang Yingqiu , Jia Jianbo , Wang Jianguo
Published: March 2015

It is difficult to monitor dopamine (DA) accurately with a bare glassy carbon electrode because of the interference of ascorbic acid (AA). In this paper, a method for the determination of DA in an AA solution using differential pulse voltammetry was established. Because AA loses its electrochemical activity after being oxidized, hydrogen peroxide was used to oxidize AA, and the interference of AA was completely eliminated. As a result, trace DA could be directly determined in the AA solution with a bare glassy carbon electrode. When trace DA was determined in a 1.0 mmol L−1 AA solution, there was a wide linear range from 3.0×10−8 mol L−1 to 1.0×10−5 mol L−1. The application of this method was demonstrated by the selective measurement of DA in an injection without pretreatment.
High Sensitive Microsensor Based on Organic‐Inorganic Composite for Two‐Dimensional Mapping of H2O2 by SECM
Authors: Justino Danielle Diniz , Torres Isabel Lourenço , de Cássia Silva Luz Rita , Damos Flavio Santos
Published: March 2015

The present work describes the development of a selective, sensitive and stable sensing microsensor for scanning electrochemical microscopy (SECM) to measure H2O2 during electrochemical reduction of oxygen. The microsensor is based on graphene and Poly(3,4‐ethylenedioxythiophene) composite as support to iron (III) hexacyanoferrate (II) (PEDOT/graphene/FeIII4[FeII(CN)6]3 microsensor). The electrochemical properties of the PEDOT/graphene/FeIII4[FeII(CN)6]3 microsensor were investigated by cyclic voltammetry (CV) and scanning electrochemical microscopy (SECM). The PEDOT/graphene/FeIII4[FeII(CN)6]3 microsensor showed an excellent electrocatalytic activity toward hydrogen peroxide (H2O2) reduction with a diminution of the overpotential of about 500 mV in comparison to the process at a bare gold microelectrode. The microsensor presented excellent performance for two dimensional mapping of H2O2 by SECM in 0.1 mol L−1 phosphate buffer solution (pH 7.0). Under optimized conditions, a linear response range from 1 up to 1000 µmol L−1 was obtained with a sensitivity of 0.08 nA L µmol−1 and limit of detection of 0.5 µmol L−1.
Hydrothermal Growth of Ag‐Doped ZnO Nanoparticles on Electrospun Cellulose Nanofibrous Mats for Catechol Detection
Authors: Fu Jiapeng , Pang Zengyuan , Yang Jie , Yang Zhanping , Cao Jianhua , Xu Yang , Huang Fenglin , Wei Qufu
Published: March 2015

We fabricated a novel hierarchical composite mat composed of electrospun cellulose nanofibers decorated with Ag‐doped ZnO (Ag‐ZnO) nanoparticles and further demonstrated its potential application as the efficient laccase (Lac) biosensor substrate material. The cyclic voltammograms revealed that the Ag‐ZnO/cellulose nanofibrous mat provided an excellent microenvironment for Lac immobilization and benefited direct electron transfer of Lac. The fabricated Lac/Ag‐ZnO/cellulose/GCE exhibited a highly sensitive detection of catechol with a wide linear range from 0.995 to 811 µM and a low detection limit of 0.205 µM. The results indicated that Ag‐ZnO/cellulose nanofibers were the promising nanostructured materials for the construction of different biosensors.
A Nitrite Electrochemical Sensor Based on Boron‐Doped Diamond Planar Electrochemical Microcells Modified with a Monolacunary Silicotungstate Polyoxoanion
Authors: Sahraoui Yosra , Sbartai Amel , Chaliaa Sana , Maaref Abderrazak , Haddad Amor , Jaffrezic‐Renault Nicole
Published: March 2015

A new boron doped diamond microcells (BDD) was modified, for rapid, selective and highly sensitive determination of nitrite, using a coating film of polyoxometalates (POMs), formed by cyclic voltammetry on the molecular p‐phenylenediamine (PPD) functionalized BDD. The scanning electron microscopy (SEM) technique was used to examine the morphology of (PPD/SiW11) modified (BDD) electrode. It was found that (SiW11) layer was uniformly formed on the electrode surface. It was observed that (BDD/PPD/SiW11) showed excellent electrocatalytic activities towards nitrite ion. Under the selected conditions, the anodic peak maximum at −0.6 V was linear versus nitrite concentration in the 40 µM–4 mM range, and the detection limit obtained was 20 µM. The newly developed electrode has been successfully applied to the determination of nitrite content in real river water samples.
Uric Acid Determination by Adsorptive Stripping Voltammetry on Multiwall Carbon Nanotubes Based Screen‐Printed Electrodes
Authors: Fanjul‐Bolado Pablo , Santos David Hernández , Montoya Virgilio Macho , Costa‐García Agustín
Published: March 2015

A sensitive electroanalytical methodology for the determination of uric acid in real samples using adsorptive voltammetry at a multiwalled carbon nanotubes (MWCNT) modified screen printed electrode (SPCE) is presented. Adsorption of uric acid takes place at open circuit potential at an optimized pH 5.0. Studies about the effect of accumulation time and scan rate on the analytical signal were developed and confirm the adsorption nature of the electrodic process. Quantitative analysis of uric acid by using its oxidation process at +0.18 V (vs. an Ag pseudoreference electrode) was carried out with an accumulation time of 5 min. Thus, a linear voltammetric based reproducible determination of uric acid (RSD 5 %) in the range 1–100 µM was obtained. The method was then successfully used for the determination of uric acid in real clinical samples of urine without detection of interferences. The proposed methodology only requires a dilution of the real sample and present advantages as low cost and easy handling for non specialized technicians.
Enhanced Performance of Lithium‐Ion Batteries with Copper Oxide Microspheres @ Graphene Oxide Micro/Nanocomposite Electrodes
Authors: Xu Yi‐Tao , Guo Ying , Jiang Hong , Xie Xiao‐Bin , Zhao Bo , Zhu Peng‐Li , Fu Xian‐Zhu , Sun Rong , Wong Ching‐Ping
Published: March 2015

CuO microspheres are obtained from thermal oxidation of Cu2O microspheres. A facile approach directed by electrostatic self‐assembly is used to fabricate graphene oxide wrapped CuO (CuO@GO). GO nanosheets directly used in batteries could reduce the preparation cost and pollution relative to reduced graphene oxide. As coating layers, GO could be electrochemically reduced to graphene in situ to obtain an additional 3D conductive network. The CuO@GO core–shell micro/nanocomposites exhibit significantly improved lithium storage capacity and cycling performance as compared to CuO microspheres or the physical mixture of CuO microspheres and GO nanosheets (CuO–GO‐PM). Under a current density of 100 mA g−1, CuO@GO retains a high discharge capacity of approximately 590 mAh g−1 for up to 50 cycles. After 200 cycles at a current density of 1000 mA g−1, the discharge capacity of the CuO@GO is approximately 313 mAh g−1, which is approximately 3 times larger than that of the CuO microspheres and CuO–GO‐PM.
Increased mitochondrial fission and volume density by blocking glutamate excitotoxicity protect glaucomatous optic nerve head astrocytes
Authors: Ju Won‐Kyu , Kim Keun‐Young , Noh You Hyun , Hoshijima Masahiko , Lukas Thomas J. , Ellisman Mark H. , Weinreb Robert N. , Perkins Guy A.
Published: March 2015

Abnormal structure and function of astrocytes have been observed within the lamina cribrosa region of the optic nerve head (ONH) in glaucomatous neurodegeneration. Glutamate excitotoxicity‐mediated mitochondrial alteration has been implicated in experimental glaucoma. However, the relationships among glutamate excitotoxicity, mitochondrial alteration and ONH astrocytes in the pathogenesis of glaucoma remain unknown. We found that functionalN‐methyl‐d‐aspartate (NMDA) receptors (NRs) are present in human ONH astrocytes and that glaucomatous human ONH astrocytes have increased expression levels of NRs and the glutamate aspartate transporter. Glaucomatous human ONH astrocytes exhibit mitochondrial fission that is linked to increased expression of dynamin‐related protein 1 and its phosphorylation at Serine 616. In BAC ALDH1L1 eGFP or Thy1‐CFP transgenic mice, NMDA treatment induced axon loss as well as hypertrophic morphology and mitochondrial fission in astrocytes of the glial lamina. In human ONH astrocytes, NMDA treatmentin vitrotriggered mitochondrial fission by decreasing mitochondrial length and number, thereby reducing mitochondrial volume density. However, blocking excitotoxicity by memantine (MEM) prevented these alterations by increasing mitochondrial length, number and volume density. In glaucomatous DBA/2J (D2) mice, blocking excitotoxicity by MEM inhibited the morphological alteration as well as increased mitochondrial number and volume density in astrocytes of the glial lamina. However, blocking excitotoxicity decreased autophagosome/autolysosome volume density in both astrocytes and axons in the glial lamina of glaucomatous D2 mice. These findings provide evidence that blocking excitotoxicity prevents ONH astrocyte dysfunction in glaucomatous neurodegeneration by increasing mitochondrial fission, increasing mitochondrial volume density and length, and decreasing autophagosome/autolysosome formation. GLIA 2015;63:736–753
Simultaneous nitrification and denitrification by novel heterotrophs in remediation of fish processing effluent
Authors: Mishra Saurabh S. , Markande Anoop R. , Keluskar Radhika P. , Karunasagar Indrani , Nayak Binaya B.
Published: March 2015

Three isolatesviz.Lysinibacillussp. HT13,Alcaligenessp. HT15 andProteussp. HT37 isolated from fish processing effluent and having a C/N ratio of 2, removed 218, 169, and 400 µg cell−1 day−1NH4+‐N, respectively without subsequent build up of nitrite or nitrate. Ability of the selected isolates in removing NH4+‐N, NO2−‐N, and NO3−‐N was checked in the presence of four commonly reported and tested effluent carbon sourcesviz. pyruvate, glycerol, methanol, and acetate. Further, when supplemented to fish processing wastewater containing 234 ppm total Kjeldahl's nitrogen,Lysinibacillussp. HT13,Alcaligenessp. HT15, andProteussp. HT37 could remediate 95.74, 86.17, and 76.6% nitrogen, respectively in 48 h. This is the first report of aLysinibacillussp. carrying out aerobically the process of simultaneous nitrification and denitrification. The results demonstrate the potential of the isolates for use in treatment of fish processing effluents and demonstrating the efficient removal of ammonia.
Microcredit and Empowerment of Urban Women: A Study from Eastern India
Authors: Pal Debdatta , Dutta Oindrilla
Published: March 2015

A positive social and financial change is detected in the lives of women members of the government‐sponsored Golden Jubilee Urban Employment Scheme.
Does Microfinance Cause or Reduce Suicides? Policy Recommendations for Reducing Borrower Stress
Authors: Ashta Arvind , Khan Saleh , Otto Philipp
Published: March 2015

Male suicides seem to accompany microfinance growth and penetration.
Academic Research on Crowdfunders: What's Been Done and What's To Come?
Authors: Macht Stephanie A. , Weatherston Jamie
Published: March 2015

The majority of published work refers to the pre‐investment phase of the crowdfunding process, with only very little academic knowledge currently relating to the post‐investment phase.
The effect of a tailored electro‐migrating corrosion inhibitor on the corrosion performance of chloride‐contaminated reinforced concrete
Authors: Fei F.‐L. , Hu J. , Yu Q.‐J. , Wei J.‐X. , Nong Y.‐B.
Published: March 2015

In this paper, the corrosion performance of chloride‐contaminated reinforced concrete in the presence of the electrochemically injected (ECI) imidazoline quaternary ammonium salt (IQS) corrosion inhibitor was investigated, by using electrochemical measurements and surface analysis. The XPS tests showed that ECI treatment not only accelerated the migration rate of IQS corrosion inhibitor in concrete, but also effectively extracted Cl‐ ions out of concrete, which is beneficial for preventing the corrosion initiation of the reinforcement; further, a larger current density was related to a faster migration rate of IQS corrosion inhibitor. The electrochemical measurements indicated that the ECI treatment significantly increased the corrosion resistance of the reinforcement. The surface observation of the reinforcement revealed that a less amount of corrosion products formed on the reinforcement surface for specimens with the ECI treatment. The related corrosion inhibition mechanisms of the electrochemically injected IQS to embedded reinforcement were also discussed.
Discrete Biogeography Based Optimization for Feature Selection in Molecular Signatures
Authors: Liu Bo , Tian Meihong , Zhang Chunhua , Li Xiangtao
Published: March 2015

Biomarker discovery from high‐dimensional data is a complex task in the development of efficient cancer diagnoses and classification. However, these data are usually redundant and noisy, and only a subset of them present distinct profiles for different classes of samples. Thus, selecting high discriminative genes from gene expression data has become increasingly interesting in the field of bioinformatics. In this paper, a discrete biogeography based optimization is proposed to select the good subset of informative gene relevant to the classification. In the proposed algorithm, firstly, the fisher‐markov selector is used to choose fixed number of gene data. Secondly, to make biogeography based optimization suitable for the feature selection problem; discrete migration model and discrete mutation model are proposed to balance the exploration and exploitation ability. Then, discrete biogeography based optimization, as we called DBBO, is proposed by integrating discrete migration model and discrete mutation model. Finally, the DBBO method is used for feature selection, and three classifiers are used as the classifier with the 10 fold cross‐validation method. In order to show the effective and efficiency of the algorithm, the proposed algorithm is tested on four breast cancer dataset benchmarks. Comparison with genetic algorithm, particle swarm optimization, differential evolution algorithm and hybrid biogeography based optimization, experimental results demonstrate that the proposed method is better or at least comparable with previous method from literature when considering the quality of the solutions obtained.
Shock Tube Effect Inside a Pyrotechnic Igniter
Authors: Buttigieg Gavin A. , Paine Gregory H. , Hsiao Ralph C.
Published: March 2015

An output closure is a critical component of a pyrotechnic igniter. It controls the heat transfer duration of initiation train, stress loading on the propellant grain, and the pressure drop during closure deployment. Normally the pressure profiles calculated by a quasi‐static interior ballistics code are adequate for igniter design evaluation. But following a case of premature closure deployment in which the propellant failed to ignite, the authors discovered that the design geometry mimicked that of a shock tube. The shock tube effect occurred whenever the high‐temperature gases of the initiator were rapidly discharged into a long conduit. The shock resultant from the initiator opened the closure prior to ignition of the ignition aid. In this paper, we report results from both quasi‐static computations for static pressure and time‐dependent simulations for dynamic pressure. Designers need to consider both static and dynamic pressure when devices have a sudden high‐pressure gas released into a conduit.
Effect of carrier gas in hydride vapor phase epitaxy on optical and structural properties of GaN
Authors: Gridneva E. , Richter E. , Feneberg M. , Weyers M. , Goldhahn R. , Tränkle G.
Published: March 2015

Variation of the H2 fraction in the carrier gas affects partial pressures and homogeneity of the species at the growth front. Changing the H2:N2 ratio thus requires readjustment of the flows of the reacting species to keep the V/III ratio at the growth front constant. In this paper the complex effect of the carrier gas composition, i.e., the H2 + N2 mixture on optical and structural properties of GaN films grown by hydride vapor phase epitaxy (HVPE) is studied. With constant input flows of the main reactants but different H2 fractions in each experiment, good morphology was observed only in a small parameter window. Partial pressures at the growth front were calculated using a commercial virtual reactor simulation tool. After readjustment of the growth species partial pressures to those which previously provided good morphology, it became possible to achieve higher growth rates, comparable morphologies, and widths of the rocking curves (FWHM) for a wide range of hydrogen fractions (0–70%). Further flow pattern correction enabled growth of 1 mm thick layers for 40–75% H2 in the carrier gas. The results of the study allow to find optimal conditions for HVPE growth of thick GaN layers when scaling up from 2 to 3 in. substrate diameter.
Semi‐polar ‐GaN templates grown on 100 mm trench‐patterned r‐plane sapphire
Authors: Brunner Frank , Edokam Francis , Zeimer Ute , John Wilfred , Prasai Deepak , Krüger Olaf , Weyers Markus
Published: March 2015

This report describes the successful realization of high‐quality semi‐polar ‐GaN templates grown on 100 mm diameter r‐plane patterned sapphire. Trench patterning is accomplished by plasma etching using a slanted SiNx mask that is formed by a resist‐reflow process and subsequent dry etching. Epitaxial overgrowth by MOVPE is optimized with the aid of in situ monitoring to trace GaN coalescence behavior and surface morphology. Wafer curvature at growth temperature exceeds typical values of c‐oriented GaN, whereas room‐temperature bow is spherical and comparable to polar material. Morphological and structural properties compare well with published data on 2 in. substrates. Threading dislocation densities of about 2 × 108 cm−2 and basal stacking fault densities in the order of 1 × 103 cm−1 are deduced from cathodoluminescence studies. Low residual impurity concentrations ([O, Si] < 1 × 1017 cm−3) have been verified.