bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polyoxometallat‐basierte ionische Flüssigkeiten als selbstreparierender Säure‐Korrosionsschutz
Authors: Herrmann Sven , Kostrzewa Monika , Wierschem Andreas , Streb Carsten 
Published: October 2014

AbstractKorrosion ist ein weltweites Problem, vor allem für Metalle. Hier wird gezeigt, wie Metalle durch hydrophobe Polxoxometallat‐basierte ionische Flüssigkeiten (POM‐ILs) leicht vor Säurekorrosion geschützt werden können. Dafür wurden Cu‐Plättchen mit bei Raumtemperatur flüssigen POM‐Ils auf Basis von Übergangsmetall‐funktionalisierten Keggin‐Anionen [SiW11O39M(H2O)]n− (M=CuII, FeIII) und quartären Alkylammonium‐Kationen (CnH2n+1)4N+ (n=7–8) beschichtet. Die Korrosionsbeständigkeit gegen Säuredämpfe und in einem simulierten sauren Regen konnte im Vergleich zu Beschichtungen auf Basis kommerzieller ILs oder fester Polyoxometallate signifikant verbessert werden. Schäden durch mechanische Beanspruchung der POM‐IL‐Beschichtung verheilen binnen einer Minute unter vollständiger Regenerierung der Schutzeigenschaften. Die Beschichtung lässt sich leicht durch Waschen mit organischen Lösungsmitteln entfernen.
PET Imaging of Bacterial Infections with Fluorine‐18‐Labeled Maltohexaose
Authors: Ning Xinghai , Seo Wonewoo , Lee Seungjun , Takemiya Kiyoko , Rafi Mohammad , Feng Xuli , Weiss Daiana , Wang Xiaojian , Williams Larry , Camp Vernon M. , Eugene Malveaux , Taylor W. Robert , Goodman Mark , Murthy Niren 
Published: October 2014

AbstractA positron emission tomography (PET) tracer composed of 18F‐labeled maltohexaose (MH18F) can image bacteria in vivo with a sensitivity and specificity that are orders of magnitude higher than those of fluorodeoxyglucose (18FDG). MH18F can detect early‐stage infections composed of as few as 105 E. coli colony‐forming units (CFUs), and can identify drug resistance in bacteria in vivo. MH18F has the potential to improve the diagnosis of bacterial infections given its unique combination of high specificity and sensitivity for bacteria.
Synthese von Triazenen mit Distickstoffmonoxid
Authors: Kiefer Gregor , Riedel Tina , Dyson Paul J. , Scopelliti Rosario , Severin Kay 
Published: October 2014

AbstractTriazene sind wertvolle Verbindungen in der organischen Chemie, für die eine Vielzahl an Anwendungen dokumentiert ist. Ferner wurden Triazene ausgiebig als potenzielle Antitumorwirkstoffe getestet. Hier beschreiben wir eine neue Methode zur Synthese von Triazenen. Das Verfahren nutzt ein Reagens, das selten in der organischen Synthese verwendet wird: Distickstoffmonoxid (N2O, “Lachgas”). N2O vermittelt die Kupplung von Lithiumamiden und Organomagnesiumverbindungen, während es selbst als Stickstoffdonor dient. Trotz des höchst inerten Charakters des Distickstoffmonoxids können die Reaktionen in Lösung unter milden Bedingungen durchgeführt werden. Ein wesentlicher Vorteil der neuen Methode ist der Zugang zu Triazenen mit Alkenyl‐ und Alkinylsubstituenten. Diese Verbindungen sind mit herkömmlichen Verfahren nur schwer erhältlich, da die benötigten Ausgangsstoffe instabil sind. Einige der neuen Alkinyltriazene zeigten eine hohe Zytotoxizität in Untersuchungen an Eierstock‐ und Brustkrebszellen in vitro.
Thermal Non‐Oxidative Aromatization of Light Alkanes Catalyzed by Gallium Nitride
Authors: Li Lu , Mu Xiaoyue , Liu Wenbo , Kong Xianghua , Fan Shizhao , Mi Zetian , Li Chao‐Jun 
Published: October 2014

AbstractThe thermal catalytic activity of GaN in non‐oxidative alkane dehydroaromatization has been discovered for the first time. The origin of the catalytic activity was studied experimentally and theoretically. Commercially available GaN powders with a wurtzite crystal structure showed superior stability and reactivity for converting light alkanes, including methane, propane, n‐butane, n‐hexane and cyclohexane into benzene at an elevated temperature with high selectivity. The catalyst is highly robust and can be used repeatedly without noticeable deactivation.
The Polymorphs of L‐Phenylalanine
Authors: Ihlefeldt Franziska Stefanie , Pettersen Fredrik Bjarte , von Bonin Aidan , Zawadzka Malgorzata , Görbitz Carl Henrik 
Published: October 2014

AbstractThe solid‐state structure of the amino acid phenylalanine (Phe) offers a potential key to understanding the behavior of a large class of important aromatic compounds. Obtaining good single crystals is, however, notoriously difficult. The structure of the common polymorph of Phe, form I, was first reported by Weissbuch et al. (as D‐Phe) in 1990, but the correctness of the published C2 unit cell with two disordered molecules in the asymmetric unit was later questioned and other space groups suggested. The identity of form I of L‐Phe is here established to be P21 with Z′=4, based on data from a well‐diffracting single crystal grown from an acetic acid solution of the amino acid. A second new polymorph, form IV, together with the two recently described forms II and III provide unprecedented information on the structural complexity of this essential amino acid. It is furthermore documented that the racemate, dl‐Phe, does not grow proper single crystals.
An Efficient Method for the In Vitro Production of Azol(in)e‐Based Cyclic Peptides
Authors: Houssen Wael E. , Bent Andrew F. , McEwan Andrew R. , Pieiller Nathalie , Tabudravu Jioji , Koehnke Jesko , Mann Greg , Adaba Rosemary I. , Thomas Louise , Hawas Usama W. , Liu Huanting , Schwarz‐Linek Ulrich , Smith Margaret C. M. , Naismith James H. , Jaspars Marcel 
Published: October 2014

AbstractHeterocycle‐containing cyclic peptides are promising scaffolds for the pharmaceutical industry but their chemical synthesis is very challenging. A new universal method has been devised to prepare these compounds by using a set of engineered marine‐derived enzymes and substrates obtained from a family of ribosomally produced and post‐translationally modified peptides called the cyanobactins. The substrate precursor peptide is engineered to have a non‐native protease cleavage site that can be rapidly cleaved. The other enzymes used are heterocyclases that convert Cys or Cys/Ser/Thr into their corresponding azolines. A macrocycle is formed using a macrocyclase enzyme, followed by oxidation of the azolines to azoles with a specific oxidase. The work is exemplified by the production of 17 macrocycles containing 6–9 residues representing 11 out of the 20 canonical amino acids.
Synthesis and characterization of PEDOT derivative with carboxyl group and its chemo sensing application as enhanced optical materials
Authors: Hu Dufen , Zhang Long , Zhang Kaixin , Duan Xuemin , Xu Jingkun , Dong Liqi , Sun Hui , Zhu Xiaofei , Zhen Shijie 
Published: October 2014

ABSTRACTPoly(4‐(((2,3‐dihydrothieno[3,4‐b][1,4]dioxin‐2‐yl)methoxy)methyl)benzoic acid) (PEDOT‐Ph‐COOH) was facilely synthesized by the direct electropolymerization of 4‐(((2,3‐dihydrothieno[3,4‐b][1,4]dioxin‐2‐yl)methoxy)methyl)benzoic acid (EDOT‐Ph‐COOH) in CH2Cl2‐Bu4NPF6 (0.10 M) system, and the PEDOT‐Ph‐COOH films were systematically investigated. The results displayed that the film had excellent reversible redox activities, good electrochemical performance, and rough and compact surface. Finally, the PEDOT‐Ph‐COOH film was used as an optical chemo‐sensor for the highly selective and sensitive detection of F−,
,
,
, Cu2+, and Fe3+ in dimethyl sulfoxide. Satisfactory results indicated that optical chemo‐sensor based on PEDOT‐Ph‐COOH possessed an excellent sensing performance and enhanced optical response, and it might be as potential promising materials, such as electrochromic devices, supercapacitors and so on. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41559.
Design of a Class of Sliding Mode Observer with Time‐Varying Delay
Authors: Xie Fa‐Xiang , Ji Bo‐Hai 
Published: October 2014

AbstractThis paper is concerned with the design of observers for a linear system with time‐varying delay in the field of structural control. A class of sliding mode observers with state and input time‐varying delays is developed on the basis of the coordinate transformation and free‐weighting matrix methods. The exponential dynamic properties of the observers are introduced to improve the performance of the observer. The delay and delay‐rate dependent conditions formulated by linear matrix inequalities (LMIs) are proposed to obtain the gains of the observers. Then, the bisection method is proposed to obtain the maximum exponential decay rate and allowable time delay. Finally, a numerical example of a fourth‐order system is used to show the feasibility and efficiency of the proposed observer.
Feasibility of raw glycerol conversion into single cell oil by zygomycetes under non‐aseptic conditions
Authors: Moustogianni Anna , Bellou Stamatia , Triantaphyllidou Irene‐Eva , Aggelis George 
Published: October 2014

ABSTRACTThe use of plant oils as feedstock for the biodiesel manufacture has many drawbacks, thus, the interest has turned to single cell oil (SCO) as an alternative. However, the production of SCO is still too expensive, mainly due to the low oil productivity and the high cost of medium sterilization required. In this work raw glycerol was converted into SCO by oleaginous Zygomycetes under non‐aseptic conditions on selective (i.e., containing essential oils and/or antibiotics) nitrogen limited media. The obtained data showed that although bacterial populations inhibited the fungal growth, lipid accumulation remained unaffected by the presence of bacteria in the growth medium compared to control experiments (conducted under aseptic conditions). Therefore, a two‐stage process was developed in which growth was performed under aseptic conditions (1st stage) followed by lipid accumulation performed under non‐aseptic conditions (2nd stage) in the presence of thyme essential oil as an antibacterial agent. Large amounts of lipids were accumulated inside the mycelia, yielding around 13% wt/wt of oil per glycerol consumed. Biotechnol. Bioeng. 2015;112: 827–831. © 2014 Wiley Periodicals, Inc.
Randomized clinical trial to evaluate mental practice in enhancing advanced laparoscopic surgical performance
Authors: Louridas M , Bonrath E M , Sinclair D A , Dedy N J , Grantcharov T P 
Published: October 2014

Abstract

Background
Mental practice, the cognitive rehearsal of a task without physical movement, is known to enhance performance in sports and music. Investigation of this technique in surgery has been limited to basic operations. The purpose of this study was to develop mental practice scripts, and to assess their effect on advanced laparoscopic skills and surgeon stress levels in a crisis scenario.

Methods
Twenty senior surgical trainees were randomized to either conventional training or mental practice groups, the latter being trained by an expert performance psychologist. Participants' skills were assessed while performing a porcine laparoscopic jejunojejunostomy as part of a crisis scenario in a simulated operating room, using the Objective Structured Assessment of Technical Skill (OSATS) and bariatric OSATS (BOSATS) instruments. Objective and subjective stress parameters were measured, as well as non-technical skills using the Non-Technical Skills for Surgeons rating tool.

Results
An improvement in OSATS (P = 0·003) and BOSATS (P = 0·003) scores was seen in the mental practice group compared with the conventional training group. Seven of ten trainees improved their technical performance during the crisis scenario, whereas four of the ten conventionally trained participants deteriorated. Mental imagery ability improved significantly following mental practice training (P = 0·011), but not in the conventional group (P = 0·083). No differences in objective or subjective stress levels or non-technical skills were evident.

Conclusion
Mental practice improves technical performance for advanced laparoscopic tasks in the simulated operating room, and allows trainees to maintain or improve their performance despite added stress.
An adaptable investigative graduate laboratory course for teaching protein purification
Authors: Carroll Christopher W. , Keller Lani C. 
Published: October 2014

AbstractThis adaptable graduate laboratory course on protein purification offers students the opportunity to explore a wide range of techniques while allowing the instructor the freedom to incorporate their own personal research interests. The course design involves two sequential purification schemes performed in a single semester. The first part comprises the expression and purification of a recombinant GFP‐binding protein from E. coli. The student‐purified GFP‐binding protein is then used in the second part of the course to immunoprecipitate GFP‐tagged proteins, and their potential interacting partners, from cell or tissue extracts. As an example, we describe the immunoprecipitation of GFP‐tagged proteins from Drosophila melanogaster larval extracts that are homologous to proteins implicated in human diseases, followed by western blotting to examine student experimental outcomes. However, the widespread availability of GFP‐fusion proteins in diverse organisms enables researchers to tailor the second part of the course to their specific research programs while maintaining the flexibility to engage students in active learning. Student evaluations indicate a genuine excitement for research and in depth knowledge of both the techniques performed and the theory behind them. © 2014 by The International Union of Biochemistry and Molecular Biology, 42(6):486–494, 2014.
The Hydrogenation of Aromatic Compounds under Mild Conditions by Using a Solid Lewis Acid and Supported Palladium Catalyst
Authors: Zhang Peng , Wu Tianbin , Hou Minqiang , Ma Jun , Liu Huizhen , Jiang Tao , Wang Weitao , Wu Congyi , Han Buxing 
Published: October 2014

AbstractAl2O3 or SiO2 particles with abundant surface hydroxyl groups can prevent side reactions of aromatic compounds with AlCl3 completely; this Lewis acid can potentially destroy the stable structure of aromatic compounds to a large extent. This discovery was successfully utilized in the highly efficient hydrogenation of benzene, toluene, and naphthalene under mild conditions co‐catalyzed by AlCl3 and Pd/Al2O3 or Pd/SiO2. Pd, AlCl3, and the surface hydroxyl groups on the support show excellent cooperative effects for the hydrogenation reactions. Theoretical studies indicate that formation of a complex, by an interaction between benzene, AlCl3, and the solid oxides, plays a key role in the highly efficient hydrogenation reactions.
Water Oxidation at Electrodes Modified with Earth‐Abundant Transition‐Metal Catalysts
Authors: Galán‐Mascarós José Ramón 
Published: October 2014

AbstractA broad and critical description of the state‐of‐the‐art in water oxidation electrocatalysts for the oxygen‐evolving reaction is given. Technologically relevant catalysts for energy production from earth‐abundant metals are highlighted.
In Situ Tetraethoxysilane‐Templated Porous Ba0.5Sr0.5Co0.8Fe0.2O3−δ Perovskite for the Oxygen Evolution Reaction
Authors: Yang Yisu , Zhou Wei , Liu Ruochen , Li Mengran , Rufford Thomas E. , Zhu Zhonghua 
Published: October 2014

AbstractThe perovskite Ba0.5Sr0.5Co0.8Fe0.2O3−δ (BSCF) is one of the best catalysts for the oxygen evolution reaction (OER), which is critical to many energy‐storage applications. However, the catalytic activity of BSCF perovskites is constrained by a low specific surface area (0.5 m2 g−1). We report here, for the first time, a facile, in situ template method using tetraethoxysilane (TEOS) to synthesize porous BSCF with surface areas of up to 32.1 m2 g−1, which to our knowledge is the highest reported surface area in a BSCF perovskite, and with excellent catalytic activity for the OER. For example, the BCSF prepared using a TEOS‐to‐BSCF ratio of 3.4 exhibited up to 35.2 A g−1 at 1.63 V versus a reversible hydrogen electrode (overpotential, η=0.4 V) and this current is 5.3 times that exhibited by nonporous BSCF (6.6 A g−1). The high activity of the porous BCSF is attributed to the additional catalytic surface sites available in the pores created by the in situ TEOS‐template method. The general application of this technique to produce porous perovskites is demonstrated in the synthesis of a second example, porous LaMnO3.
Preparation, Structural Properties and Thermal Isomerization of Hex‐3‐ene‐1,5‐diyne Bridged [2.2]Paracyclophanes
Authors: Dix Ina , Bondarenko Lidija , Jones Peter G. , Ernst Ludger , Ibrom Kerstin , Grunenberg Jörg , Boese Roland , Hopf Henning 
Published: October 2014

AbstractThe [2.2]paracyclophane moiety is used as a spacer to connect the ends of a hex‐3‐ene‐1,5‐diyne unit, a π‐system that on thermolysis usually cycloaromatizes to a benzene ring (Bergman cyclization). For the preparation of the pseudo‐geminally‐bridged system 9, the diacetylene 3 was chain‐extended to the diol 16, which after conversion to the pseudo‐geminal dibromide 17 was ring‐closed by treatment with LiHMDS/HMPA to the [2.2]paracyclophane enediyne 9. Whereas the McMurry coupling of the pseudo‐ortho bisaldehyde 24 resulted in the formation of the hexadienyne‐bridged cyclophane 27, the pseudo‐ortho‐bridged hydrocarbon 11 was obtained by preparing first the diol 28 from 24, converting the latter into the dioxolane 29, which in the last step furnished the olefin 11 by treatment with Tf2O/EtN(iPr)2. The authentic Bergman product 10 of the pseudo‐gem‐bridged hexenediyne 9 was synthesized by a conventional sequence starting from the ethynyl formyl substrate 18. Since the pseudo‐ortho‐enediyne‐bridged hydrocarbon 11 is thermally labile, its benzannelated derivate 34 was prepared. No classical Bergman cyclization reactions could be observed for any of the [2.2]paracyclophane‐bridged hexenediynes prepared here. In the pseudo‐gem‐series the fulvenes 14 and 15 were the only products that could be identified under thermal conditions (McMurry coupling); the benzannelated substrate 34 gave the benzofulvene‐bridged cyclophane 36 on photolysis. Bergman cyclizations yielding fulvene derivatives are extremely rare. The mechanism of the cyclization of 9 and 34 is discussed, using compliance constants. The structure assignments of the hydrocarbons synthesized in this study are based on spectroscopic studies as well as X‐ray structural analyses for 9, 10, 11, 27, and 34.
Triarylboranes with a 2‐Dimesitylboryl‐2’‐(N,N‐dimethylamino)biphenyl Core Unit: Structure–Property Correlations and Sensing Abilities to Discriminate Between F− and CN− Ions
Authors: Wang Chen , Jia Jiong , Zhang Wei‐Ning , Zhang Hong‐Yu , Zhao Cui‐Hua 
Published: October 2014

AbstractA series of triarylboranes, in which different substituents are introduced at the para position of the dimethylamino group of a 2‐dimesitylboryl‐2’‐(N,N‐dimethylamino)biphenyl core unit, have been comprehensively investigated to explore the effect of structural modification on photophysical properties. The introduction of electron‐accepting substituents would facilitate the HOMO→LUMO charge transfer (CT) transition. In contrast, the intramolecular CT transition is significantly prohibited when electron‐donating substituents are incorporated. Notably, the HOMO→LUMO CT transition mainly consists of the transition from the electron‐donating amino group to an electron acceptor other than boryl when a strong electron acceptor such as the dicyanovinyl group is present. This dicyanovinyl‐substituted compound displays sensing abilities to discriminate fluoride and cyanide ions. In solution in THF, the fluoride ions first bind to the boron center, then attack the α‐carbon atom of the dicyanovinyl group, whereas the cyanide anion acts on the electron‐accepting centers in the reverse sequence. As a result, the absorption and emission change in different manners upon addition of fluoride and cyanide ions.
Designed Benzothiadiazole Fluorophores for Selective Mitochondrial Imaging and Dynamics
Authors: Carvalho Pedro H. P. R. , Correa Jose R. , Guido Bruna C. , Gatto Claudia C. , De Oliveira Heibbe C. B. , Soares Thereza A. , Neto Brenno A. D. 
Published: October 2014

AbstractA series of new rationale designed 2,1,3‐benzothiadiazole (BTD) fluorescent derivatives has been synthesized and applied for cellular selective staining of cancer cells in cell‐imaging experiments. Four new synthesized BTD derivatives showed only poor or reasonable cellular selection, but with excellent fluorescence intensity and almost no background signal emitting at the blue or green channels. The knowledge gained by analysing their molecular architecture, however, allowed the planning and synthesis of a fluorescent BTD, which was then successfully tested and showed superior mitochondrial selection with outstanding results in bioimaging experiments in living cells. The new marker (named Splendor) was then compared with the commercially available MitoTracker Red (also through co‐staining experiments) and showed far better mitochondrial selection, fluorescence intensity and chemical stability. Mitochondrial imaging and tracking (dynamic changes) was possible using Splendor during the whole cellular division cycle. DFT calculations were performed to offer insights into the origin of the chemical‐ and photostability of BTD derivatives. In addition, molecular docking calculations hint at a potential molecular target for the BTD derivatives in the mitochondrial protein adenine nucleotide translocase, which may explain the mitochondrial selectivity of Splendor versus the other four BTD derivatives.
Molecularly Imprinted Photonic Polymers as Sensing Elements for the Creation of Cross‐Reactive Sensor Arrays
Authors: Xu Dan , Zhu Wei , Wang Chen , Tian Tian , Cui Jiecheng , Li Jian , Wang Hui , Li Guangtao 
Published: October 2014

AbstractBy combining molecular imprinting and colloidal crystal templating, molecularly imprinted inverse‐opal photonic polymers (MIPPs) acting as sensing elements have been exploited to create sensor arrays for the first time. With this new strategy, abundant sensing elements with differential sensing abilities were easily accessible. Because of the unique hierarchical porous structure integrated in each sensing element, high sensitivity and selectivity, fast response and self‐reporting (label‐free) detection could be simultaneously achieved. All these fascinating features indicate that MIPPs are ideal sensing elements for creating sensor arrays. By integrating the individual sensing elements on a substrate, the formed array chip delivers better portability and high‐throughput capability. As a demonstration, six kinds of contaminants were selected as analytes. The detection and discrimination of these analytes and even their mixtures in a wide range of concentrations, particularly trace amounts of analyte against a high background of other components, could be achieved, indicating the powerful capability of MIPPs‐based sensor array for sensing. These results suggest that the described strategy opens a new route for sensor array creation and should find important applications in a wide range of areas.
Domino Hydroformylation/Aldol Condensation/Hydrogenation Catalysis: Highly Selective Synthesis of Ketones from Olefins
Authors: Fang Xianjie , Jackstell Ralf , Börner Armin , Beller Matthias 
Published: October 2014

AbstractA general and highly chemo‐ and regioselective synthesis of ketones from olefins by domino hydroformylation/aldol condensation/hydrogenation reaction has been developed. A variety of olefins are efficiently converted into various ketones in good to excellent yields and regioselectivities in the presence of a specific rhodium phosphine/base–acid catalyst system.