bluuebunny/crossref_metadata_2025 huggingface dataset:
An All‐Ceramic Solid‐State Rechargeable Na+‐Battery Operated at Intermediate Temperatures
Authors: Wei Tao , Gong Yunhui , Zhao Xuan , Huang Kevin
Published: June 2014

A major challenge to the development of the next‐generation all‐solid‐state rechargeable battery technology is the inferior performance caused by insufficient ionic conductivity in the electrolyte and poor mixed ionic‐electronic conductivity in the electrodes. Here we demonstrate the utility of elevated temperature as an advantageous means of enhancing the conductivity in the electrolyte and promoting the catalytic activity at electrodes in an all‐ceramic rechargeable Na+‐battery. The new Na+‐battery consists of a 154‐μm thick Na‐β′′‐Al2O3 electrolyte membrane, a 22‐μm thick P2‐Na2/3[Fe1/2Mn1/2]O2 cathode and 52‐μm thick Na2Ti3O7‐La0.8Sr0.2MnO3 composite anode. The battery is shown to be capable of producing a reversible and stable capacity of 152 mAhg−1 at 350 °C. While the battery's achievable capacity is limited by the electrode materials employed, it does exhibit unique low self‐discharge rate, high tolerance to thermal cycling and an outstanding safety feature.
Bifunctional Separator with a Light‐Weight Carbon‐Coating for Dynamically and Statically Stable Lithium‐Sulfur Batteries
Authors: Chung Sheng‐Heng , Manthiram Arumugam
Published: June 2014

Sulfur is appealing as a high‐capacity cathode for rechargeable lithium batteries as it offers a high theoretical capacity of 1672 mA h g−1 and is abundant. However, the commercialization of Li‐S batteries is hampered by fast capacity fade during both dynamic cell cycling and static cell resting. The poor electrochemical stability is due to polysulfide diffusion, leading to a short cycle life and severe self‐discharge. Here, we present the design of a bifunctional separator with a light‐weight carbon‐coating that integrates the two necessary components already inside the cell: the conductive carbon and the separator. With no extra additives, this bifunctional carbon‐coated separator allows the use of pure sulfur cathodes involving no complex composite synthesis process, provides a high initial discharge capacity of 1389 mA h g−1 with excellent dynamic stability, and facilitates a high reversible capacity of 828 mA h g−1 after 200 cycles. In addition, the static stability is evidenced by low self‐discharge and excellent capacity retention after a 3 month rest period.
Carbon‐Interconnected Ge Nanocrystals as an Anode with Ultra‐Long‐Term Cyclability for Lithium Ion Batteries
Authors: Ngo Duc Tung , Kalubarme Ramchandra S. , Le Hang T. T. , Fisher John G. , Park Choong‐Nyeon , Kim Il‐Doo , Park Chan‐Jin
Published: June 2014

Germanium (Ge) possesses a great potential as a high‐capacity anode material for lithium ion batteries but suffers from its poor capacity retention and rate capability due to significant volume expansion by lithiation. Here, a facile synthetic route is introduced for producing nanometer‐sized Ge crystallites interconnected by carbon (GEC) via thermal decomposition of a Ge‐citrate complex followed by a calcination process in an inert atmosphere. The GEC electrode shows outstanding electrochemical performance, i.e., an almost 98.8% capacity retention of 1232 mAh g−1, even after 1000 cycles at the rate of C/2. Importantly, a high discharge capacity of 880 mAh g−1 is maintained at the very high rate of 10 C. The excellent anode performance of GEC stems from both effective buffering of carbon anchored to the Ge nanocrystals and the high open porosity of the GEC aggregated powder with an average pore diameter of 32 nm. Furthermore, the interfacial layer formed between Ge and carbon plays an essential role in prolonging the cycle life. The GEC electrode can be successfully employed as an anode for next generation lithium ion batteries.
Conjugated Polymers of Intrinsic Microporosity (C‐PIMs)
Authors: Cheng Ge , Bonillo Baltasar , Sprick Reiner S. , Adams Dave J. , Hasell Tom , Cooper Andrew I.
Published: June 2014

Conjugated microporous polymers (CMPs) have shown great potential for energy and environmental issues, however, poor solubility and processability of most of these materials limit their applications. Herein, a range of linear conjugated polymers of intrinsic microporosity (C‐PIMs) is reported, combining for the first time the properties of conjugated microporous polymers, such as tunable electronic properties and compositional variation, with those of linear polymers of intrinsic microporosity (PIMs) allowing for solution processability and film formation. These soluble materials have a number of potential applications, for example as components in devices where large, porous interfaces are combined with extended electronic conjugation.
Ultrathin Metasurface Laser Beam Shaper
Authors: Chen Xianzhong , Zhang Yan , Huang Lingling , Zhang Shuang
Published: June 2014

Driven by ground‐breaking applications in various scientific communities, metamaterial research has experienced rapid growth over the past decade. Metasurfaces, the new emerging field of metamaterials, have aroused considerable interest due to their capability of arbitrary manipulation of the phase profile at the interface. Here, an ultrathin (40 nm) broadband laser beam shaper for visible and near‐infrared light is realized experimentally by using metasurfaces consisting of a monolayer of metallic nanorods with spatially varying orientations. The abrupt phase change occurs when a circularly polarized light wave is converted to the opposite handedness. The phase distribution of the planar devices is obtained by using the Yang–Gu algorithm and then encoded to the spatial orientations of the nanorods. This approach can be used for information processing and other phase‐related techniques.
A Study on the Effect of Cosolvent Addition Pathway on the Optical and Morphological Properties of P3HT: PCBM Composite Films
Authors: Nair Sarita S. , Kumar D. , Majumdar Amitava
Published: June 2014

In this work, we present an exhaustive study on the effect of a cosolvent addition pathway on the optical, structural, and morphological characteristics of poly(3‐hexyl thiophene) (P3HT): [6, 6]‐phenyl C61‐butyric acid methyl ester (PCBM) composite films. Our recommended pathway of cosolvent addition has shown to benefit the composite film by forming more crystallized and ordered P3HT polymer domains on the film surface as revealed by the UV–vis absorption, grazing incidence X‐ray diffraction (GI‐XRD), and atomic force microscopy measurements. GI‐XRD measurements that were carried out at three grazing incidence angles (0.11°, 0.13°, and 0.3°) also substantiate a more prominent upright concentration gradient of the film processed through the modified method. The contact angle measurement reveals accumulation of more P3HT crystallites at the surface of co‐solvent modified films. A highly quenched photoluminescence signal precise phase separation between the blended components of the modified film, promoting exciton dissociation at the donor–acceptor interfaces during photoinduced excitations.
Improving Cathodes with a Polymer Interlayer in Reversed Organic Solar Cells
Authors: Tang Zheng , Tress Wolfgang , Bao Qinye , Jafari Mohammad J. , Bergqvist Jonas , Ederth Thomas , Andersson Mats R. , Inganäs Olle
Published: June 2014

The effects of cathode modification by a conjugated polymer interlayer PFPA1 on the performance of reversed organic solar cells (substrate/cathode/active layer/transparent anode) based on different active material systems and different substrate electrodes are systematically investigated. A reduction of the work function irrespective of the substrate cathode used is observed upon the deposition of the PFPA1 interlayer, which is further related to an improved built‐in electric field and open‐circuit voltage. The amphiphilic character of the PFPA1 interlayer alters the surface energy of the substrate cathode, leading to the formation of a better active layer morphology aiding efficient exciton dissociation and photocurrent extraction in the modified solar cells. Hence, internal quantum efficiency is found to be significantly higher than that of their unmodified counterparts, while optically, the modified and unmodified solar cells are identical. Moreover, the deep highest occupied molecular orbital (HOMO) of the PFPA1 interlayer improves the selectivity for all investigated substrate cathodes, thus enhancing the fill factor.
Extractive distillation with ionic liquids: A review
Authors: Lei Zhigang , Dai Chengna , Zhu Jiqin , Chen Biaohua
Published: June 2014

Extractive distillation is commonly used for the separation of azeotropic or close‐boiling mixtures in the chemical industry. During the past decade, the use of ionic liquids (ILs) as entrainers has received considerable attention due to their unique advantages when applied in extractive distillation. This work is devoted to providing an easy‐to‐read and comprehensive review on the recent progress made by chemical engineers, focusing on the issues of predictive thermodynamic models, structure‐property relations, separation mechanisms, and process simulation and optimization. This review spans from the molecular level to the industrial scale, to provide a theoretical insight into the molecular interactions between ILs and the components to be separated. Moreover, a comprehensive database on the vapor–liquid equilibria and activity coefficients at infinite dilution concerning ILs is provided as Supporting Information. Concluding remarks are made on the unsolved scientific issues with respect to this promising special distillation technology. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3312–3329, 2014
Der intermetalloide Cluster [(Cp*AlCu)6H4], Stabilisierung eines Cu6‐Kerns in einer oktaedrischen Al6‐Hülle: molekulare Modellverbindungen für Hume‐Rothery‐Nanophasen
Authors: Ganesamoorthy Chelladurai , Weßing Jana , Kroll Clarissa , Seidel Rüdiger W. , Gemel Christian , Fischer Roland A.
Published: June 2014

Definierte molekulare Modelle für katalyserelevante Oberflächenreaktionen an Hume‐Rothery‐Nanophasen sind sehr selten. Der intermetalloide Al‐Cu‐Cluster [(Cp*AlCu)6H4] wird selektiv bei der Reaktion von [(Cp*Al)4] und [(PPh3CuH)6] gebildet. Die höhere Affinität von Cp*Al zu Kupfer ermöglicht die Substitution der Phosphinliganden der Kupferhydridvorstufe und die Stabilisierung des Cu6‐Kerns durch dessen Einbettung in einen Al6‐Käfig. Der erhaltene Hydridocluster M12H4 reagiert mit Benzonitril in einer stöchiometrischen Hydrometallierung zu [(Cp*AlCu)6H3(NCHPh)].
Chemie an Graphen und Graphenoxid – eine Herausforderung für Synthesechemiker
Authors: Eigler Siegfried , Hirsch Andreas
Published: June 2014

Die chemische Herstellung von Graphen sowie seine kontrollierte nasschemische Modifikation sind anspruchsvolle Ziele für Synthesechemiker. Ebenso bedarf es ausgeklügelter analytischer Methoden, um Reaktionsprodukte zu charakterisieren. In diesem Aufsatz beschreiben wir zunächst die Struktur von Graphen und Graphenoxid. Anschließend stellen wir die gängigsten Methoden für die Synthese dieser auf Kohlenstoff basierenden Nanomaterialien vor. Wir fassen den wissenschaftlichen Erkenntnisstand zur nichtkovalenten und kovalenten chemischen Funktionalisierung zusammen und legen besonderen Wert auf die Unterscheidung der Begriffe Graphit und Graphen sowie Graphitoxid und Graphenoxid. Für die Entwicklung alltagstauglicher Anwendungen ist ein verbessertes grundlegendes Verständnis der Struktur und chemischen Eigenschaften von Graphen und Graphenoxid unerlässlich.
100 Jahre Max‐Planck‐Institut für Kohlenforschung
Authors: Reetz Manfred T.
Published: June 2014

Dieser Essay beschreibt die institutionelle und wissenschaftliche Entwicklung des Max‐Planck‐Instituts für Kohlenforschung in Mülheim an der Ruhr, des Nachfolge‐Instituts des 1914 gegründeten Kaiser‐Wilhelm‐Instituts für Kohlenforschung. Die vier Hauptteile des Essays entsprechen den vier historischen Perioden, die mit den jeweiligen Direktoren zusammenhängen: 1) Franz Fischer; 2) Karl Ziegler; 3) Günther Wilke; 4) die von Manfred T. Reetz initiierte Umstrukturierung, in deren Folge ein Direktorium bestehend aus fünf gleichberechtigten Direktoren mit jeweils einer Abteilung etabliert wurde. Zusätzlich zu den rein historischen und politischen Entwicklungen werden auch Höhepunkte der Forschung aus den vier Perioden beschrieben.
Microfluidic Studies of Carbon Dioxide
Authors: Abolhasani Milad , Günther Axel , Kumacheva Eugenia
Published: June 2014

Carbon dioxide (CO2) sequestration, storage and recycling will greatly benefit from comprehensive studies of physical and chemical gas–liquid processes involving CO2. Over the past five years, microfluidics emerged as a valuable tool in CO2‐related research, due to superior mass and heat transfer, reduced axial dispersion, well‐defined gas–liquid interfacial areas and the ability to vary reagent concentrations in a high‐throughput manner. This Minireview highlights recent progress in microfluidic studies of CO2‐related processes, including dissolution of CO2 in physical solvents, CO2 reactions, the utilization of CO2 in materials science, and the use of supercritical CO2 as a “green” solvent.
Magnesierung funktionalisierter Heterocyclen und Acrylate unter Verwendung von TMPMgCl⋅LiCl in kontinuierlichem Fluss
Authors: Petersen Trine P. , Becker Matthias R. , Knochel Paul
Published: June 2014

Es wird eine Durchflussmethode für die Metallierung funktionalisierter Heterocyclen (Pyridine, Pyrimidine, Thiophene und Thiazole) und verschiedener Acrylate unter Verwendung der starken, nichtnukleophilen Base TMPMgCl⋅LiCl beschrieben. Die Flussbedingungen ermöglichen Magnesierungen unter zweckmäßigeren Bedingungen als die entsprechenden Kolbenreaktionen, die oft tiefe Temperaturen und lange Reaktionszeiten benötigen. Ferner sind die Durchflussreaktionen ohne weitere Optimierung skalierbar und erlauben Metallierungen, die nicht das gewünschte Produkt im Reaktionskolben ergeben, wie die Magnesierung empfindlicher Acrylderivate. Die Magnesiumspezies reagieren im Anschluss mit verschiedenen Elektrophilen, wodurch vielfältige Funktionalitäten eingeführt werden.
Total Synthesis of Marinomycin A Based on a Direct Dimerization Strategy
Authors: Nishimaru Tatsuya , Kondo Masashi , Takeshita Kimito , Takahashi Keisuke , Ishihara Jun , Hatakeyama Susumi
Published: June 2014

The asymmetric total synthesis of (+)‐marinomycin A, a 44‐membered macrodiolide antitumor agent and antibiotic isolated from a marine actinomycete, Marinispora strain CNQ‐140, is reported. The key features of the synthesis include the highly convergent stereocontrolled construction of the monomeric hydroxy salicylate starting from asymmetric epoxidation of the σ‐symmetrical dialkenyl carbinol, and an unprecedented direct dimerization through NaHMDS‐promoted double transesterification.
General Synthesis of Multi‐Shelled Mixed Metal Oxide Hollow Spheres with Superior Lithium Storage Properties
Authors: Zhang Genqiang , Lou Xiong Wen (David)
Published: June 2014

Complex hollow structures of transition metal oxides, especially mixed metal oxides, could be promising for different applications such as lithium ion batteries. However, it remains a great challenge to fabricate well‐defined hollow spheres with multiple shells for mixed transition metal oxides. Herein, we have developed a new “penetration–solidification–annealing” strategy which can realize the synthesis of various mixed metal oxide multi‐shelled hollow spheres. Importantly, it is found that multi‐shelled hollow spheres possess impressive lithium storage properties with both high specific capacity and excellent cycling stability. Specifically, the carbon‐coated CoMn2O4 triple‐shelled hollow spheres exhibit a specific capacity of 726.7 mA h g−1 and a nearly 100 % capacity retention after 200 cycles. The present general strategy could represent a milestone in design and synthesis of mixed metal oxide complex hollow spheres and their promising uses in different areas.
Synthesis of (Carbo)nucleoside Analogues by [3+2] Annulation of Aminocyclopropanes
Authors: Racine Sophie , de Nanteuil Florian , Serrano Eloisa , Waser Jérôme
Published: June 2014

(Carbo)nucleoside derivatives constitute an important class of pharmaceuticals, yet there are only few convergent methods to access new analogues. Here, we report the first synthesis of thymine‐, uracil‐, and 5‐fluorouracil‐substituted diester donor–acceptor cyclopropanes and their use in the indium‐ and tin‐catalyzed [3+2] annulations with aldehydes, ketones, and enol ethers. The obtained diester products could be easily decarboxylated and reduced to the corresponding alcohols. The method gives access to a broad range of new (carbo)nucleoside analogues in only four or five steps and will be highly useful for the synthesis of libraries of bioactive compounds.
An Ultrastable Anode for Long‐Life Room‐Temperature Sodium‐Ion Batteries
Authors: Yu Haijun , Ren Yang , Xiao Dongdong , Guo Shaohua , Zhu Yanbei , Qian Yumin , Gu Lin , Zhou Haoshen
Published: June 2014

Sodium‐ion batteries are important alternative energy storage devices that have recently come again into focus for the development of large‐scale energy storage devices because sodium is an abundant and low‐cost material. However, the development of electrode materials with long‐term stability has remained a great challenge. A novel negative‐electrode material, a P2‐type layered oxide with the chemical composition Na2/3Co1/3Ti2/3O2, exhibits outstanding cycle stability (ca. 84.84 % capacity retention for 3000 cycles, very small decrease in the volume (0.046 %) after 500 cycles), good rate capability (ca. 41 % capacity retention at a discharge/charge rate of 10 C), and a usable reversible capacity of about 90 mAh g−1 with a safe average storage voltage of approximately 0.7 V in the sodium half‐cell. This P2‐type layered oxide is a promising anode material for sodium‐ion batteries with a long cycle life and should greatly promote the development of room‐temperature sodium‐ion batteries.
(Aminocarbene)(Divinyltetramethyldisiloxane)Iron(0) Compounds: A Class of Low‐Coordinate Iron(0) Reagents
Authors: Zhang Hezhong , Ouyang Zhenwu , Liu Yuesheng , Zhang Qiang , Wang Lei , Deng Liang
Published: June 2014

The combined use of aminocarbene and divinyltetramethyldisiloxane (dvtms) as supporting ligands enables the access of unprecedented low‐coordinate iron(0) alkene compounds [LnFe(η2:η2‐dvtms)] (L=N‐heterocyclic carbene (NHC) or cyclic (alkyl)(amino)carbene (CAAC), n=1 or 2) from the reactions of FeCl2 with alkali‐metal reducing agents, free aminocarbene ligands, and dvtms. The iron(0) species deliver their {LnFe0} fragments to perform redox reactions with Ph2SiH2, S8, Se, and DippN3, furnishing novel aminocarbene‐supported iron(IV) silylene, all‐ferrous iron–sulfur/selenium cubanes, and bis(imido)iron(IV) compounds. These conversions demonstrate the potential synthetic utility of the carbene‐supported iron(0) complexes as a valuable class of low‐coordinate iron(0) reagents.
Aminopropylated PEG as a novel, eco‐friendly and biodegradable basic catalyst for bis‐Michael addition to α,β‐unsaturated ketones under solvent‐free conditions
Authors: Khan Tabassum , Siddiqui Zeba N.
Published: June 2014

A solvent‐free and highly efficient protocol has been developed for the synthesis of novel bis‐Michael addition products (3a, 3b, 3c, 3d, 3e, 3f, 3g, 3h, 3i, 3j, 3k, 3l, 3m, 3n, 3o) using aminopropylated PEG‐6000 (NH2‐PEG) as a biodegradable and recyclable catalyst in excellent yields under solvent‐free conditions. Other remarkable features of this environmentally benign protocol are shorter reaction time, tolerance of a wide range of C―H‐activated acids, high yield of products, and simple experimental and work‐up procedure as compared to conventional methods. The NH2‐PEG catalyst is characterized by using FT‐IR, powder XRD and scanning electron microscopy–energy dispersion X‐ray spectrometric analyses. The catalyst can be recycled several times without significant loss of its catalytic activity. Copyright © 2014 John Wiley & Sons, Ltd.
Polyvinyl chloride composites filled with olive stone flour: Mechanical, thermal, and water absorption properties
Authors: Naghmouchi Ilhem , Mutjé Pere , Boufi Sami
Published: June 2014

The production of olive oil leads to considerable amounts of solid waste mainly composed of hard woody endocarp called olive stones. The aim of this work is to explore the possible use of ground olive stones as fillers for polyvinyl chloride (PVC), to elaborate a cost‐effective composite material with a solid loading of up to 50 wt %. After grinding, the ensuing olive stone flour (OSF) was incorporated into a PVC matrix via melt compounding and injection molding to elaborate PVC‐OSF‐based composites with a filler content up to 50 wt %. The evolution of the mechanical performance, the impact property, the water absorbance, and wear resistance behavior, according to the OSF content, were investigated. The addition of OSF was shown to enhance the stiffness of the matrix, but at the expense of its mechanical strength. However, the strength of the composite did not fall as low as 30 MPa, and therefore, meets the requirements for many applications in plastic‐based materials. The thermal properties of the ensuing composites were also studied by thermogravimetric analysis. The results show that the addition of OSF may be effective in increasing the stiffness of the PVC‐based composite and in reducing the solid residue in the olive oil industry production. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41083.
Hg(II) removal from HCl solutions using a tetraalkylphosphonium ionic liquid impregnated onto Amberlite XAD‐7
Authors: Navarro Ricardo , Alba Janette , Saucedo Imelda , Guibal Eric
Published: June 2014

Extractant impregnated resins (EIRs) were prepared by impregnation of Amberlite XAD‐7 with tetraalkylphosphonium chloride ionic liquid (IL). The EIRs were tested for the sorption of Hg(II) in HCl solutions. Mercury is bound on the EIR through an ion exchange mechanism involving chloroanionic species and the IL. The effect of HCl concentration and IL content is studied and the sorption isotherms are obtained in 1 M HCl solutions: the sorption capacity linearly increases with IL loading up to 100 mg Hg L−1. A little fraction of the IL immobilized on the resin (about 40 mg IL g−1) is tightly bound to the polymer limiting its reactivity with metal ions. The uptake kinetics are mainly controlled by intraparticle diffusion. At high IL loading the kinetics are slowed down, while the temperature has a limited impact. Nitric acid can be used for desorbing mercury and recycling the EIR for at least five cycles. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41086.
Antimicrobial cytocompatible pentaerythritol triacrylate‐co‐trimethylolpropane composite scaffolds for orthopaedic implants
Authors: Smoak Mollie , Chen Cong , Qureshi Ammar , Garber Leah , Pojman John A. , Janes Marlene E. , Hayes Daniel J.
Published: June 2014

As of 2010, 5.3 million orthopedic surgeries are performed each year, and this number is expected to increase to 6.2 million by 2020. On average, 27.7% of all orthopedic surgeries result in infection which often leads to osteomyelitis and the loss of supporting bone. In this study, we describe two synthetic bone grafts, or augmentation methods, for a biodegradable, silver nanoparticle (SNPs) containing antimicrobial scaffolds composed of pentaerythritol triacrylate‐co‐trimethylolpropane tris (3‐mercaptopropionate) (PETA) and hydroxyapatite (HA). This osteoinductive and degradable material is designed to stimulate proliferation of bone progenitor cells, and provide controlled release of antimicrobial components. The first method, denoted as the “incorporating method,” involves dissolving SNPs in ethanol, butanol, or isopropanol and directly incorporating the particles into the scaffold prior to polymerization. The second method, “coating method,” involves submerging fabricated scaffolds into their respective SNPs‐solution and mixing for 24 h. The coating method allowed better distribution and release of SNPs from the surface of the composites when exposed to extracellular media. The in vitro release of silver for both methods was quantified by inductively coupled plasma optical emission spectroscopy (ICP‐OES). The scaffolds made by means of the coating method showed increased release of silver with respect to time; no silver leached from the scaffolds formed by the incorporating method. Use of Alamar Blue assay demonstrated that the SNPs incorporation did not affect cell viability when tested with hASCs. The scaffolds formed by the coating method inhibited the proliferation of Staphylococcus aureus 99.5% and Escherichia coli by 99.9% within 24 h. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41099.
Thermal stability of modified end‐capped poly(lactic acid)
Authors: Berger Katrin , Gregorova Adriana
Published: June 2014

The influence of functional end groups on the thermal stability of poly(lactic acid) (PLA) in nitrogen‐ and oxygen‐enriched atmospheres has been investigated in this article using differential scanning calorimetry, thermogravimetric analysis (TGA), and dynamic mechanical analysis (DMA). Functional end groups of PLA were modified by succinic anhydride and l‐cysteine by the addition–elimination reaction. PLA was synthesized by azeotropic condensation of l‐lactic acid in xylene and characterized by nuclear magnetic resonance. The values of the activation energies determined by TGA in nitrogen and oxygen atmospheres revealed that the character of functional end groups has remarkable influence on the thermal stability of PLA. Moreover, DMA confirmed the strong influence of functional end groups of PLA on polymer chains motion. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41105.
Remarkable Shape‐Sustaining, Load‐Bearing, and Self‐Healing Properties Displayed by a Supramolecular Gel Derived from a Bis‐pyridyl‐bis‐amide of L‐Phenyl Alanine
Authors: Das Uttam Kumar , Banerjee Subhabrata , Dastidar Parthasarathi
Published: June 2014

A series of bis‐amides decorated with pyridyl and phenyl moieties derived from L‐amino acids having an innocent side chain (L‐alanine and L‐phenyl alanine) were synthesized as potential low‐molecular‐weight gelators (LMWGs). Both protic and aprotic solvents were found to be gelled by most of the bis‐amides with moderate to excellent gelation efficiency (minimum gelator concentration=0.32–4.0 wt. % and gel–sol dissociation temperature Tgel=52–110 °C). The gels were characterized by rheology, DSC, SEM, TEM, and temperature‐variable 1H NMR measurements. pH‐dependent gelation studies revealed that the pyridyl moieties took part in gelation. Structure–property correlation was attempted using single‐crystal X‐ray and powder X‐ray diffraction data. Remarkably, one of the bis‐pyridyl bis‐amide gelators, namely 3,3‐Phe (3‐pyridyl bis‐amide of L‐phenylalanine) displayed outstanding shape‐sustaining, load‐bearing, and self‐healing properties.
Superior Supercapacitor Properties of Composite Powders with Amorphous NiO Nanoclusters Distributed Uniformly in an Amorphous Carbon Matrix
Authors: Choi Seung Ho , Kang Yun Chan , Choi Yun Ju , Kim Yang Soo
Published: June 2014

Amorphous nickel oxide–carbon composite powders have been prepared using a facile spray‐drying process. The nickel nitrate–citrate hydrate precursor powders were transformed into an amorphous NiO–carbon composite powder through a post‐treatment at 250 °C for 1 h. The excellent supercapacitor performance of the amorphous NiO–carbon composite powder can be ascribed to the unique electrochemical behavior of the ultrafine amorphous NiO nanoclusters.
Sumanenemonoone Imines Bridged by Redox‐Active π‐Conjugated Unit: Synthesis, Stepwise Coordination to Palladium(II), and Laser‐Induced Formation of Nitrogen‐Doped Graphitic Carbon
Authors: Amaya Toru , Inada Yuhi , Shimizu Yasutomo , Saeki Akinori , Tsuji Ryotaro , Seki Shu , Hirao Toshikazu
Published: June 2014

Sumanenemonoone imine compounds bridged by a redox‐active π‐conjugated unit on the basis of the conversion between 1,4‐phenylenediamine and 1,4‐benzoquinonediimine were synthesized and characterized. The stepwise coordination of the imino groups to PdII in the sumanenemonoone imine compound bridged by 1,4‐benzoquinonediimine was indicated by the titration experiment. Laser irradiation of a film of the metal‐free quionediimine gave nitrogen‐doped graphitic carbon, which was supported by an increase in conductivity and by Raman spectroscopy. The obtained graphitic carbon corresponds to carbonous compounds thermally treated at approximately 700–1000 °C. The ratio of nitrogen and carbon relative to that in the starting compound was nearly completely retained (5.4 % decrease).
Patient-reported outcomes 5–8 years after ultrasound-guided foam sclerotherapy for varicose veins
Authors: Darvall K A L , Bate G R , Bradbury A W
Published: June 2014

Background

The aim was to determine the long-term (5–8 years) outcomes of ultrasound-guided foam sclerotherapy (UGFS) for varicose veins using health-related quality of life (HRQL), patient-reported outcomes (PROMs), patient satisfaction and retreatment rates.

Methods

Consecutive patients undergoing UGFS between April 2004 and May 2007 were invited for review at least 5 years after treatment. Patients completed generic (Short Form 12) and disease-specific (Aberdeen Varicose Vein Symptom Severity Score, AVSS) HRQL instruments, and questionnaires enquiring about lower limb symptoms, lifestyle factors and satisfaction with treatment. Data on retreatments were recorded prospectively.

Results

A total of 391 limbs in 285 patients were included (81·2 per cent response rate) at a median of 71 (i.q.r. 67–78) months following first UGFS treatment. Originally 72·1 per cent had symptomatic, uncomplicated varicose veins, 21·9 per cent had undergone surgery previously, 87·2 per cent had treatment of great saphenous veins and 19·9 per cent treatment of short saphenous veins. Disease-specific HRQL scores improved significantly at long-term follow-up, with 88·5 per cent having an improved AVSS compared with baseline. Regarding lower limb symptoms and lifestyle improvement, 62·7–93·8 per cent of patients had their pretreatment expectations met or exceeded. Overall, 82·0 per cent were very satisfied with their treatment and only 3·3 per cent were dissatisfied; 91·0 per cent would recommend the treatment to others. Some 15·3 per cent of limbs required retreatment by 5 years (Kaplan–Meier analysis).

Conclusion

UGFS has durable results as reported by PROMs to at least 5 years. Only 15·3 per cent of limbs required retreatment for recurrence during follow-up.
Chemoenzymatic Synthesis of Bifunctional Polyubiquitin Substrates for Monitoring Ubiquitin Chain Remodeling
Authors: Trang Vivian H. , Rodgers Margaret L. , Boyle Kevin J. , Hoskins Aaron A. , Strieter Eric R.
Published: June 2014

Covalent attachment of ubiquitin to target proteins is one of the most pervasive post‐translational modifications in eukaryotes. Target proteins are often modified with polymeric ubiquitin chains of defined lengths and linkages that may further undergo dynamic changes in composition in response to cellular signals. Biochemical characterization of the enzymes responsible for building and destroying ubiquitin chains is often thwarted by the lack of methods for preparation of the appropriate substrates containing probes for biochemical or biophysical studies. We have discovered that a yeast ubiquitin C‐terminal hydrolase (Yuh1) also catalyzes transamidation reactions that can be exploited to prepare site‐specifically modified polyubiquitin chains produced by thiol‐ene chemistry. We have used this chemoenzymatic approach to prepare dual‐functionalized ubiquitin chains containing fluorophore and biotin modifications. These dual‐functionalized ubiquitin chains enabled the first real‐time assay of ubiquitin chain disassembly by a human deubiquitinase (DUB) enzyme by single molecule fluorescence microscopy. In summary, this work provides a powerful new tool for elucidating the mechanisms of DUBs and other ubiquitin processing enzymes.
Modulation of Amyloid‐β Aggregation by Histidine‐Coordinating Cobalt(III) Schiff Base Complexes
Authors: Heffern Marie C. , Velasco Pauline T. , Matosziuk Lauren M. , Coomes Joseph L. , Karras Constantine , Ratner Mark A. , Klein William L. , Eckermann Amanda L. , Meade Thomas J.
Published: June 2014

Oligomers of the Aβ42 peptide are significant neurotoxins linked to Alzheimer's disease (AD). Histidine (His) residues present at the N terminus of Aβ42 are believed to influence toxicity by either serving as metal–ion binding sites (which promote oligomerization and oxidative damage) or facilitating synaptic binding. Transition metal complexes that bind to these residues and modulate Aβ toxicity have emerged as therapeutic candidates. Cobalt(III) Schiff base complexes (Co–sb) were evaluated for their ability to interact with Aβ peptides. HPLC‐MS, NMR, fluorescence, and DFT studies demonstrated that Co–sb complexes could interact with the His residues in a truncated Aβ16 peptide representing the Aβ42 N terminus. Coordination of Co–sb complexes altered the structure of Aβ42 peptides and promoted the formation of large soluble oligomers. Interestingly, this structural perturbation of Aβ correlated to reduced synaptic binding to hippocampal neurons. These results demonstrate the promise of Co–sb complexes in anti‐AD therapeutic approaches.
The Role of the Executive‐Level Student Services Officer Within a Community College Organizational Structure
Authors: Hernandez John , Hernández Ignacio
Published: June 2014

The unique nature and mission of community colleges directly shapes the role and function of a senior student affairs officer (SSAO). Broadly, the community college mission is shaped by a vision of fulfilling several commitments to local communities. This includes admitting all applicants through an open access admissions policy and providing comprehensive educational programs leading to associate's degrees, career and technical education, basic skills education, certificates, and the transfer pathway to baccalaureate‐granting institutions, as well as lifelong learning courses. This chapter will discuss the role of the SSAO within a community college organizational structure. Career paths will be explored including competencies needed in this role. Implications include promising practices for aspiring SSAOs as well as recommendations for search committees who must no longer neglect SSAOs as potential presidents.
Excellence Within Student Affairs: Understanding the Practice of Integrating Academic and Student Affairs
Authors: Ozaki C. Casey , Hornak Anne M.
Published: June 2014

In this final chapter, the authors synthesize and draw from chapters across this volume to provide concluding remarks and recommendations. The authors suggest that core to the discussion of excellence of student affairs in community colleges are the concepts of integration and collaboration. As professionals tasked with supporting the student learning experience at institutions with diverse, commuter populations, the formal and informal relationships and collaborations between student and academic affairs are critical.
Pure and Alloyed Copper‐Based Nanoparticles Supported on Activated Carbon: Synthesis and Electrocatalytic Application in the Reduction of Nitrobenzene
Authors: Sheng Xia , Wouters Benny , Breugelmans Tom , Hubin Annick , Vankelecom Ivo F. J. , Pescarmona Paolo P.
Published: June 2014

A series of Cu–CuxO, Pt–Cu alloy, and Pt nanoparticles supported on inexpensive activated carbon with large surface area were developed as electrocatalysts for the reduction of nitrobenzene. This reaction can produce useful chemicals with the potential to cogenerate electricity if applied in a fuel cell. Both the nature of the metal employed and of the carbon material used as support play an important role in determining the performance of the electrocatalysts. Cu‐based materials display lower onset potentials for the reduction of nitrobenzene, whereas the features of the activated carbon influence the stability of the electrocatalysts. The most promising electrocatalyst consisted of highly dispersed and very small Cu–CuxO nanoparticles (∼4 nm) supported on Norit activated carbon, which were prepared using H2 as reductant. A chronoamperometric test in acidic ethanolic medium gave good conversion of nitrobenzene over this electrocatalyst, with azoxybenzene as the major product.
Synthesis of Hybrid Electroactive Materials by Low‐Potential Electropolymerization of Gold Nanoparticles Capped with Tailored EDOT‐Thiophene Precursor Units
Authors: Yassin Ali , Oçafrain Maiténa , Blanchard Philippe , Mallet Romain , Roncali Jean
Published: June 2014

The synthesis of gold nanoparticles (GNPs) capped with alkanethiols with terminal bithiophenic polymerizable groups, consisting of 3,4‐ethylenedioxythiophene (EDOT) and 3‐alkylsulfanylthiophene, is described. Transmission electron microscopy (TEM) and light diffusion show that these stabilized GNPs have an average size of 2–3 nm with low polydispersity. The electrochemical behavior of C10S‐Au is investigated in dichloromethane in the presence of Bu4NPF6. The results show that these capped GNPs undergo straightforward and efficient electropolymerization under potentiodynamic or potentiostatic conditions. TEM images show that the electrodeposited films of the composite material present a very homogeneous structure, in which the size of the GNPs incorporated into the polythiophene matrix is unchanged. Results of cyclic voltammetry and spectroelectrochemistry obtained on polymer films deposited on platinum electrodes and transparent indium tin oxide electrodes, respectively, show that the reversible charging–discharging process and electrochromic behavior typical of poly(thiophenes) are preserved in the hybrid electroactive material.
A 3D Nanoporous Ni–Mo Electrocatalyst with Negligible Overpotential for Alkaline Hydrogen Evolution
Authors: Wang Yuhang , Zhang Guoxin , Xu Wenwen , Wan Pengbo , Lu Zhiyi , Li Yaping , Sun Xiaoming
Published: June 2014

3D Ni–Mo electrocatalysts with well‐controlled composition, dimensions and nanoporosity are fabricated using a facile and effective electrodeposition technique on Cu foam. These catalysts exhibit enhanced stability and activity for the hydrogen evolution reaction (HER). By optimizing the Ni/Mo ratio, electrodeposition current density, and reaction time, the overpotential for the HER is reduced to 10 mV. The ultrahigh activity and stability of these catalysts are the highest among non‐precious‐metal electrocatalysts previously reported. The optimized Ni–Mo electrocatalyst has similar overpotential and a much higher current density compared to Pt/C. The improved HER performance is attributed to the Ni/Mo ratio (4:1), the large surface area, and the in situ growth method, which provides a well‐defined catalyst. These catalysts are potentially an attractive alternative to Pt in HERs, and therefore represent new technological opportunities for the development of renewable and economic hydrogen production.
Oleochemical‐Tethered SBA‐15‐Type Silicates with Tunable Nanoscopic Order, Carboxylic Surface, and Hydrophobic Framework: Cellular Toxicity, Hemolysis, and Antibacterial Activity
Authors: Pędziwiatr‐Werbicka Elżbieta , Miłowska Katarzyna , Podlas Marta , Marcinkowska Monika , Ferenc Małgorzata , Brahmi Younes , Katir Nadia , Majoral Jean‐Pierre , Felczak Aleksandra , Boruszewska Aleksandra , Lisowska Katarzyna , Bryszewska Maria , El Kadib Abdelkrim
Published: June 2014

Novel silicates were prepared by using silylated natural fatty acids (derived from triglyceride renewable oils) as co‐condensing reagents in presence of tetraethyl orthosilicate (TEOS) and the triblock copolymer, pluronic P123, as a structure directing agent. A series of carboxylic acid functionalized SBA‐15‐type mesoporous silicates were obtained with tunable nanoscopic order and reactive functional groups that allow the conjugation of amino probes by peptide coupling. Photophysical studies of the covalently linked aminopyrene substantiated that the internal framework of these materials have pronounced hydrophobicity. Moreover, phase separation that can emanate from the bulkiness of the starting fatty silanes has been ruled out owing to the absence of excimers after aminopyrene grafting. The hemotoxicity, cytotoxicity, and antimicrobial activity of these novel silicates were then evaluated. Without discrimination, the functionalized silicates show a significant decrease of red blood cell hemolysis as compared to bare SBA‐15‐silica material. Within the modified silicate series, germanium‐free mesoporous silicates induce only a slight decrease in cell viability and, more interestingly, they exhibit negligible hemolytic effect. Moreover, increasing their concentration in the medium reduces the concentration of released hemoglobin as a result of Hb adsorption. Promising antimicrobial properties were also observed for these silicates with a slight dependency on whether phenylgermanium fragments were present within the silicate framework.
High‐Yield Formation of Substituted Tetracyanobutadienes from Reaction of Ynamides with Tetracyanoethylene
Authors: Betou Marie , Kerisit Nicolas , Meledje Esme , Leroux Yann R. , Katan Claudine , Halet Jean‐François , Guillemin Jean‐Claude , Trolez Yann
Published: June 2014

A high‐yielding sequence of [2+2] cycloaddition–retroelectrocyclization of ynamides with tetracyanoethylene (TCNE) is described. The reaction provided tetracyanobutadiene (TCBD) species, which were characterized by various techniques. DFT and TD‐DFT calculations were also performed to complement experimental findings.
Enhanced Photoinduced Electron Transfer at the Surface of Charged Lipid Bilayers
Authors: Limburg Bart , Laisné Guillaume , Bouwman Elisabeth , Bonnet Sylvestre
Published: June 2014

Photocatalytic systems often suffer from poor quantum yields due to fast charge recombination: The energy‐wasting annihilation of the photochemically created charge‐separated state. In this report, we show that the efficiency of photoinduced electron transfer from a sacrificial electron donor to positively charged methyl viologen, or to negatively charged 5,5′‐dithiobis(2‐nitrobenzoate), increases dramatically upon addition of charged phospholipid vesicles if the charge of the lipids is of the same sign as that of the electron acceptor. Centrifugation and UV/Vis titration experiments showed that the charged photosensitizers adsorb at the liposome surface, that is, where the photocatalytic reaction takes place. The increased photoelectron transfer efficiency in the presence of charged liposomes has been ascribed to preferential electrostatic interactions between the photosensitizer and the membrane, which prevents the formation of photosensitizer–electron‐acceptor complexes that are inactive towards photoreduction. Furthermore, it is shown that the addition of liposomes results in a decrease in photoproduct inhibition, which is caused by repulsion of the reduced electron acceptor by the photocatalytic site. Thus, liposomes can be used as a support to perform efficient photocatalysis; the charged photoproducts are pushed away from the liposomes and represent “soluble electrons” that can be physically separated from the place where they were generated.
Synthesis of Unsymmetrically Substituted Phosphane Oxides (R1R2P(O)H) and Phosphinous Acids (R1R2POH)
Authors: Allefeld Nadine , Grasse Michael , Ignat'ev Nikolai , Hoge Berthold
Published: June 2014

Invited for the cover of this issue is the group of Berthold Hoge at the University of Bielefeld. The image depicts the delicate balance between the unusual form of a phosphinous acid with respect to the corresponding phosphane oxide tautomer by the influence of electron‐withdrawing groups. Read the full text of the article at 10.1002/chem.201402425.
Development of an Iron(II)‐Catalyzed Aerobic Catechol Cleavage and Biomimetic Synthesis of Betanidin
Authors: Guimond Nicolas , Mayer Peter , Trauner Dirk
Published: June 2014

An aerobic iron(II)‐catalyzed cleavage of catechols was developed. This reaction allows for the preparation of 2‐methoxy‐2 H‐pyrans that can be employed as versatile building blocks for synthesis. The utility of this biomimetic oxidative cleavage is featured in the synthesis of betanidin, a natural colorant with antioxidant properties.
2‐Nitroveratryl as a Photocleavable Thiol‐Protecting Group for Directed Disulfide Bond Formation in the Chemical Synthesis of Insulin
Authors: Karas John A. , Scanlon Denis B. , Forbes Briony E. , Vetter Irina , Lewis Richard J. , Gardiner James , Separovic Frances , Wade John D. , Hossain Mohammed A.
Published: June 2014

Chemical synthesis of peptides can allow the option of sequential formation of multiple cysteines through exploitation of judiciously chosen regioselective thiol‐protecting groups. We report the use of 2‐nitroveratryl (oNv) as a new orthogonal group that can be cleaved by photolysis under ambient conditions. In combination with complementary S‐pyridinesulfenyl activation, disulfide bonds are formed rapidly in situ. The preparation of Fmoc‐Cys(oNv)‐OH is described together with its use for the solid‐phase synthesis of complex cystine‐rich peptides, such as insulin.
High‐Resolution 3D Proton MRI of Hyperpolarized Gas Enabled by Parahydrogen and Rh/TiO2 Heterogeneous Catalyst
Authors: Kovtunov Kirill V. , Barskiy Danila A. , Coffey Aaron M. , Truong Milton L. , Salnikov Oleg G. , Khudorozhkov Alexander K. , Inozemtseva Elizaveta A. , Prosvirin Igor P. , Bukhtiyarov Valery I. , Waddell Kevin W. , Chekmenev Eduard Y. , Koptyug Igor V.
Published: June 2014

Several supported metal catalysts were synthesized, characterized, and tested in heterogeneous hydrogenation of propene with parahydrogen to maximize nuclear spin hyperpolarization of propane gas using parahydrogen induced polarization (PHIP). The Rh/TiO2 catalyst with a metal particle size of 1.6 nm was found to be the most active and effective in the pairwise hydrogen addition and robust, demonstrating reproducible results with multiple hydrogenation experiments and stability for ≥1.5 years. 3D 1H magnetic resonance imaging (MRI) of 1 % hyperpolarized flowing gas with microscale spatial resolution (625×625×625 μm3) and large imaging matrix (128×128×32) was demonstrated by using a preclinical 4.7 T scanner and 17.4 s imaging scan time.
[18F]CuCF3: A [18F]Trifluoromethylating Agent for Arylboronic Acids and Aryl Iodides
Authors: Ivashkin Pavel , Lemonnier Gérald , Cousin Jonathan , Grégoire Vincent , Labar Daniel , Jubault Philippe , Pannecoucke Xavier
Published: June 2014

Positron emission tomography has emerged as the leading method for medical imaging with fluorine‐18 as the most widely used radioactive isotope. Here we report a semi‐automated method for the preparation of valuable [18F]trifluoromethylcopper, as well as its use for the radiosynthesis of [18F]trifluoromethylarenes and heteroarenes. Mild conditions of [18F]trifluoromethylation make this method particularly useful for the radiosynthesis of pharmacologically relevant [18F]trifluoromethylarenes and heteroarenes.
Investigation of the Impact and Compression Behaviour of Wet Granules
Authors: Müller Peter , Aman Sergej , Tomas Jürgen
Published: June 2014

Das Materialverhalten dominant elastisch‐plastischer γ‐Al2O3‐Granulate wurde experimentell mittels dynamischer Prall‐ und quasistatischer Druckversuche bis zum Bruch untersucht. Aus dem Vergleich der ermittelten Verteilungen der Bruchgeschwindigkeit und der spezifischen Bruchenergie lassen sich geschwindigkeitsabhängige Einflüsse bei der Beanspruchung wie viskoses Verhalten ableiten. Der Einfluss der Partikelgröße und der Feuchtebeladung bei Prall‐ und Bruchbeanspruchung werden ebenfalls analysiert.