bluuebunny/crossref_metadata_2025_split huggingface dataset:
Carbonfasern, der Werkstoff des 21. Jahrhunderts
Authors: Kirsten Martin , Freudenberg Christiane , Cherif Chokri 
Published: January 2015

AbstractSeit langer Zeit dominiert der Werkstoff Stahl als Bewehrungsmaterial den Betonbau, da er vielzählige Vorteile bietet. Jedoch resultieren aus seiner unzureichenden Korrosionsbeständigkeit und der damit verbundenen Notwendigkeit einer ausreichend großen Betonüberdeckung auch einige Nachteile. Diese lassen sich mit textilen Hochleistungsmaterialien vermeiden, wobei insbesondere Carbon sich als Bewehrungsmaterial eignet. Mit der Entwicklung von Carbonfasern und deren Einsatz als textile Verstärkungsmaterialien haben sich völlig neue Wege bei der Herstellung von Faserkunststoffverbunden insbesondere für tragende Bauteile eröffnet. Aufgrund der herausragenden Eigenschaften und des damit verbundenen enormen Leichtbaupotenzials sowie der gezielt einstellbaren mechanischen, thermischen und elektrischen Eigenschaften halten Carbonfasern Einzug in viele Industriezweige, wie den Fahrzeug‐ und Maschinenbau, die Luft‐ und Raumfahrttechnik, die Energieerzeugung (Windkraft) und das Bauwesen im Bereich der Textilbetontechnologie. Das Ausgangsmaterial für Carbonfasern besteht zum überwiegenden Teil aus dem erdölbasierten Polyacrylnitril, welches bereits in Faserform mehrere thermische Behandlungen durchläuft, um die Eigenschaften der Carbonfasern auszubilden und gezielt einzustellen.Carbon Fibers, material of the 21st century – Textile basis for filigree, high bearing concrete building elementsSteel as reinforcing material has dominated the civil engineering for a long time. However, some disadvantages occur by its insufficient corrosion resistance and the associated need for an adequate concrete cover. Those can be avoided using textile high performance materials, where carbon shows a high potential being promoted as concrete reinforcement material of the future. The development of carbon fibers opens a new field producing reinforced fiber composites. The outstanding properties and the resulting huge light weight construction potential as well as its defined tunable mechanical, thermal and electrical properties, carbon fibers find their way into a lot of industrial branches, namely like automotive‐ and mechanical engineering, aerospace engineering, energy production (wind energy) and building industry, especially textile reinforced concrete. The material for carbon fibers mainly bases on polyacrylonitrile made of mineral oil, which already in form of fibers passes through several thermal treatments to form and to design the properties of the carbon fibers.
Freie Formen mit Textilbeton
Authors: Scheerer Silke , Michler Harald 
Published: January 2015

AbstractTextilbeton ist ideal, um Leichtbau mit Beton zu betreiben, da bereits mit sehr dünnen Schichten eine hohe Tragfähigkeit erreicht werden kann. Aufgrund der Leichtigkeit und der Flexibilität seiner Bewehrung ist Textilbeton vor allem prädestiniert dafür, freie Formen zu realisieren. In Verbindung mit innovativen Herstellungsmethoden besteht zudem die Möglichkeit, eine neue Formensprache im Betonbau zu etablieren. Dass dieses Potenzial nicht nur Ingenieure und Architekten interessant ist, sondern auch für Künstler und Designer, wird im zweiten Teil des Beitrags gezeigt.Free forms with TRCTextile reinforced concrete is ideal to build lightweight concrete structures, because a high load capacity can already be reached with very thin layers. The textile reinforcement is lightweight and flexible. Therefore, TRC is especially predestined to realize free forms. In combination with innovative production methods, we also have the option to develop a new distinctive design idiom in concrete construction. In the paper we also show, that this enormous potential is not only interesting for engineers and architects, but also for artists and designers.
Biegetragverhalten von textilbetonverstärkten Platten
Authors: Beckmann Birgit , Frenzel Michael , Lorenz Enrico , Schladitz Frank , Rempel Sergej 
Published: January 2015

AbstractIn diesem Beitrag werden Plattenversuche zur Bestimmung der Biegetragfähigkeit von textilbetonverstärkten Stahlbetonplatten vorgestellt. Hierzu wurden Stahlbetonplattenstreifen mit Stützweiten von 3 bis 7 m mit einer nachträglich aufgebrachten Textilbetonschicht verstärkt und im Vier‐Punkt‐Biegeversuch bis zum Bruch belastet. Ihre Tragfähigkeiten werden mit denen der unverstärkten Referenzplatten verglichen. Durch Variation der Anzahl an textilen Bewehrungslagen wird gezeigt, in welchem Maß die Biegetragfähigkeit von Stahlbetonplatten durch den Einsatz des Carbontextils erhöht werden kann, und die Verstärkungswirkung von Textilbeton nachgewiesen. Die experimentell ermittelten Tragfähigkeiten werden mit den vorab rechnerisch ermittelten verglichen. Durch die gute Übereinstimmung der Werte wird das Bemessungskonzept für Textilbetonverstärkungen bestätigt und nachgewiesen.Flexural behaviour of textile reinforced concrete slabsFlexuaral load experiments on RC slabs with additional textile strengthening are presented in this work. RC slabs of 3 to 7 m in length are subsequently strengthened with a layer of textile reinforced concrete (TRC) and loaded until rupture in four‐point‐flexural‐tests. Their load bearing capacities are compared to the reference slabs without textile strengthening reinforcement. Varying the number of textile reinforcement layers, it is shown to what extent the flexural load bearing capacity of RC slabs can be increased by means of the carbon textile reinforcement. The strengthening effect of TRC is proved. The experimental results are compared to the ones calculated afore. The good agreement of the experimental and calculated results validates the design concept of TRC strengthening.
Surgical complications after open and laparoscopic surgery for perforated peptic ulcer in a nationwide cohort
Authors: Wilhelmsen M , Møller M H , Rosenstock S 
Published: January 2015

Abstract

Background
Surgery for perforated peptic ulcer (PPU) is associated with a risk of complications. The frequency and severity of reoperative surgery is poorly described. The aims of the present study were to characterize the frequency, procedure-associated risk and mortality associated with reoperation after surgery for PPU.

Methods
All patients treated surgically for PPU in Denmark between 2011 and 2013 were included. Baseline and clinical data, including 90-day mortality and detailed information on reoperative surgery, were collected from the Danish Clinical Register of Emergency Surgery. Distribution frequencies of reoperation stratified by type of surgical approach (laparoscopy or open) were reported. The crude and adjusted risk associations between surgical approach and reoperation were assessed by regression analysis and reported as odds ratio (OR) with 95 per cent c.i. Sensitivity analyses were carried out.

Results
A total of 726 patients were included, of whom 238 (32·8 per cent) were treated laparoscopically and 178 (24·5 per cent) had a laparoscopic procedure converted to laparotomy. Overall, 124 (17·1 per cent) of 726 patients underwent reoperation. A persistent leak was the most frequent cause (43 patients, 5·9 per cent), followed by wound dehiscence (34, 4·7 per cent). The crude risk of reoperative surgery was higher in patients who underwent laparotomy and those with procedures converted to open surgery than in patients who had laparoscopic repair: OR 1·98 (95 per cent c.i. 1·19 to 3·27) and 2·36 (1·37 to 4·08) respectively. The difference was confirmed when adjusted for age, surgical delay, co-morbidity and American Society of Anesthesiologists fitness grade. However, the intention-to-treat sensitivity analysis (laparoscopy including conversions) demonstrated no significant difference in risk. The risk of death within 90 days was greater in patients who had reoperation: crude and adjusted OR 1·53 (1·00 to 2·34) and 1·06 (0·65 to 1·72) respectively.

Conclusion
Reoperation was necessary in almost one in every five patients operated on for PPU. Laparoscopy was associated with lower risk of reoperation than laparotomy or a converted procedure. However, there was a risk of bias, including confounding by indication.
Effect of resveratrol on restoring spermatogenesis in experimental cryptorchid mice and analysis of related differentially expressed proteins
Authors: Li Enzhong , Guo Yuping , Wang Gailing , Chen Fujia , Li Qingwang 
Published: January 2015

AbstractThe present study aimed to evaluate the effect of trans‐Resveratrol on spermatogenesis. Male Kunming suckling mice (10 days old) were surgically rendered cryptorchid and subcutaneously injected with trans‐Resveratrol at doses of 5, 10, 20, and 40 µg/g/day as groups I, II, III, and IV, respectively, for 35 days. Animals in the control group received 10 µL/mouse/day of olive oil. Serum estradiol, testosterone, FSH, and LH levels were measured on day 45. Tissue analysis and sperm morphological abnormalities analysis were done. Results showed that in the control group and group I only spermatogonia and primary spermatocytes were present, whereas spermatogenesis was totally restored in groups II, III, and IV. Sperm counts in groups III and IV were remarkably higher than the control group (P < 0.05). The morphological abnormalities in resveratrol‐treated groups were higher than the mature mice. Serum estradiol levels in the resveratrol‐treated groups were not significantly different from the control group, but were lower than the mature mice (P < 0.05). There was no significant difference in serum testosterone levels between the resveratrol‐treated groups and mature mice, but the levels in the resveratrol‐treated groups was significantly lower than the control group (P < 0.05). No significant influence of trans‐Resveratrol was observed on serum FSH levels in all cryptorchid mice. Serum LH levels in groups I, II, and III were higher than the control group. These results indicate that trans‐Resveratrol restores spermatogenesis in cryptorchid mice. In addition, proteomic analysis between the 20 μg/g/day resveratrol‐treated group and the control group was carried out, and five kinds of proteins (BAF250, ZFP261, CHD1L, RBBP9, and SOHLH2) were identified. The expression of SOHLH2 increased, while that of BAF250, ZFP261, CHD1L, and RBBP9 decreased in the 20 µg/g/day resveratrol‐treated group, indicating that SOHLH2 may contribute to testicular germ cell differentiation.
Stromal derived factor‐1α in hippocampus radial glial cells in vitro regulates the migration of neural progenitor cells
Authors: Ding Hui , Jin Guo‐Hua , Zou Lin‐Qing , Zhang Xiao‐Qing , Li Hao‐Ming , Tao Xue‐Lei , Zhang Xin‐Hua , Qin Jian‐Bing , Tian Mei‐Ling 
Published: January 2015

AbstractStromal derived factor‐1α (SDF‐1α), a critical chemokine that promotes cell homing to target tissues, was presumed to be involved in the traumatic brain injury cortex. In this study, we determined the expression of SDF‐1α in the hippocampus after transection of the fimbria fornix (FF). Realtime PCR and ELISA showed that mRNA transcription and SDF‐1α proteins increased significantly after FF transection. In vitro, the expression of SDF‐1α in radial glial cells (RGCs) incubated with deafferented hippocampus extracts was observed to be greater than in those incubated with normal hippocampus extracts. The co‐culture of neural progenitor cells (NPCs) and RGCs indicated that the extracts of deafferented hippocampus induced more NPCs migrating toward RGCs than the normal extracts. Suppression or overexpression of SDF‐1α in RGCs markedly either decreased or increased, respectively, the migration of NPCs. These results suggest that after FF transection, SDF‐1α in the deafferented hippocampus was upregulated and might play an important role in RGC induction of NPC migration; therefore, SDF‐1α is a target for additional research for determining new therapy for brain injuries.
An (R)‐Imine Reductase Biocatalyst for the Asymmetric Reduction of Cyclic Imines
Authors: Hussain Shahed , Leipold Friedemann , Man Henry , Wells Elizabeth , France Scott P. , Mulholland Keith R. , Grogan Gideon , Turner Nicholas J. 
Published: January 2015

AbstractAlthough the range of biocatalysts available for the synthesis of enantiomerically pure chiral amines continues to expand, few existing methods provide access to secondary amines. To address this shortcoming, we have over‐expressed the gene for an (R)‐imine reductase [(R)‐IRED] from Streptomyces sp. GF3587 in Escherichia coli to create a recombinant whole‐cell biocatalyst for the asymmetric reduction of prochiral imines. The (R)‐IRED was screened against a panel of cyclic imines and two iminium ions and was shown to possess high catalytic activity and enantioselectivity. Preparative‐scale synthesis of the alkaloid (R)‐coniine (90 % yield; 99 % ee) from the imine precursor was performed on a gram‐scale. A homology model of the enzyme active site, based on the structure of a closely related (R)‐IRED from Streptomyces kanamyceticus, was constructed and used to identify potential amino acids as targets for mutagenesis.
Gold‐ and Silver‐Catalyzed Intramolecular Cyclizations of Indolylcyclopropenes for the Divergent Synthesis of Azepinoindoles and Spiroindoline Piperidines
Authors: Zhu Peng‐Long , Zhang Zhen , Tang Xiang‐Ying , Marek Ilan , Shi Min 
Published: January 2015

AbstractGold‐ and silver‐catalyzed novel intramolecular cycloisomerizations of nitrogen or carbon‐tethered indolylcyclopropenes to furnish biologically and pharmaceutically valuable azepino‐[4,5‐b]indole and spiro[indoline‐3,4′‐piperidine] derivatives have been developed. Both reactions exhibit high chemoselectivity and stereospecificity through completely different reaction pathways. Based on mechanistic studies, it is well demonstrated that gold and silver catalysts act differently to promote the anti‐ and syn‐addition and the steric effect of the catalysts play an important role to switch the addition mode, affording the catalyst‐controlled‐divergent synthesis.
Chemisorption, Morphology, and Structure of a n‐Type Perylene Diimide Derivative at the Interface with Gold: Influence on Devices from Thin Films to Single Molecules
Authors: Ciccullo Francesca , Savu Sabine‐Antonia , Gerbi Andrea , Bauer Maximilian , Ovsyannikov Ruslan , Cassinese Antonio , Chassé Thomas , Casu Maria Benedetta 
Published: January 2015

AbstractWe have investigated thin films of a perylene diimide derivative with a cyano‐functionalized core (PDI‐8CN2) deposited on Au(111) single crystals from the monolayer to the multilayer regime. We found that PDI‐8CN2 is chemisorbed on gold. The molecules experience a thickness‐dependent reorientation, and a 2D growth mode with molecular stepped terraces is achieved adopting low deposition rates. The obtained results are discussed in terms of their impact on field effect devices, also clarifying why the use of substrate/contact treatments, decoupling PDI‐8CN2 molecules from the substrate/contacts, is beneficial for such devices. Our results also suggest that perylene diimide derivatives with CN bay‐functionalization are very promising candidates for single‐molecule electronic devices.
Subclass‐Specific Labeling of Protein‐Reactive Natural Products with Customized Nucleophilic Probes
Authors: Rudolf Georg C. , Koch Maximilian F. , Mandl Franziska A. M. , Sieber Stephan A. 
Published: January 2015

AbstractNatural products represent a rich source of bioactive compounds that constitute a large fraction of approved drugs. Among those are molecules with electrophilic scaffolds, such as Michael acceptors, β‐lactams, and epoxides that irreversibly inhibit essential enzymes based on their catalytic mechanism. In the search for novel bioactive molecules, current methods are challenged by the frequent rediscovery of known chemical entities. Herein small nucleophilic probes that attack electrophilic natural products and enhance their detection by HPLC‐UV and HPLC‐MS are introduced. A screen of diverse probe designs revealed one compound with a desired selectivity for epoxide‐ and maleimide‐based antibiotics. Correspondingly, the natural products showdomycin and phosphomycin could be selectively targeted in extracts of their natural producing organism, in which the probe‐modified molecules exhibited superior retention and MS detection relative to their unmodified counterparts. This method may thus help to discover small, electrophilic molecules that might otherwise easily elude detection in complex samples.
New Energetic Polynitrotetrazoles
Authors: Kettner Marcos A. , Klapötke Thomas M. 
Published: January 2015

AbstractThis combined experimental, theoretical and comparative study details the syntheses and chemical characterisation of two new energetic polynitromethyl tetrazole derivatives, namely, 2‐(2‐nitro‐2‐azapropyl)‐5‐(trinitromethyl)‐2 H‐tetrazole and its fluorine‐containing analogue 2‐(2‐nitro‐2‐azapropyl)‐5‐(fluorodinitromethyl)‐2 H‐tetrazole. Their crystal structures and energetic behaviour are compared to those of their starting materials, the ammonium salts of the corresponding 5‐(polynitromethyl)‐2 H‐tetrazoles. Additionally, the crystal structures of two further related polynitrotetrazoles are presented.
Synthesis of the Antimicrobial S‐Linked Glycopeptide, Glycocin F
Authors: Brimble Margaret A. , Edwards Pat J. , Harris Paul W. R. , Norris Gillian E. , Patchett Mark L. , Wright Tom H. , Yang Sung‐Hyun , Carley Sarah E. 
Published: January 2015

AbstractThe first total synthesis of glycocin F, a uniquely diglycosylated antimicrobial peptide bearing a rare S‐linked N‐acetylglucosamine (GlcNAc) moiety in addition to an O‐linked GlcNAc, has been accomplished using a native chemical ligation strategy. The synthetic and naturally occurring peptides were compared by HPLC, mass spectrometry, NMR and CD spectroscopy, and their stability towards chymotrypsin digestion and antimicrobial activity were measured. This is the first comprehensive structural and functional comparison of a naturally occurring glycocin with an active synthetic analogue.
RhI‐Catalyzed Benzo/[7+1] Cycloaddition of Cyclopropyl‐Benzocyclobutenes and CO by Merging Thermal and Metal‐Catalyzed CC Bond Cleavages
Authors: Fu Xu‐Fei , Xiang Yu , Yu Zhi‐Xiang 
Published: January 2015

AbstractA Rh‐catalyzed benzo/[7+1] cycloaddition of cyclopropyl‐benzocyclobutenes (CP‐BCBs) and CO to benzocyclooctenones has been developed. In this reaction, CP‐BCB acts as a benzo/7‐C synthon and the reaction involves two CC bond cleavages: a thermal electrocyclic ring‐opening of the four‐membered ring in CP‐BCB and a Rh‐catalyzed CC cleavage of the cyclopropane ring.
Iron‐Catalyzed Trifluoromethylation of Enamide
Authors: Rey‐Rodriguez Romain , Retailleau Pascal , Bonnet Pascal , Gillaizeau Isabelle 
Published: January 2015

AbstractHerein the first example of the iron(II)‐catalyzed trifluoromethylation of enamide using mild and simple reaction conditions is reported. The method is cost‐effective and uses the easy‐to‐handle Togni’s reagent as the electrophilic CF3 source. This transformation is totally regioselective at the C3 position of enamides and exhibits broad substrate scope, good functional group tolerance and thus demonstrates its useful application in a late‐stage fluorination strategy.
A Short Scalable Route to (−)‐α‐Kainic Acid Using Pt‐Catalyzed Direct Allylic Amination
Authors: Zhang Ming , Watanabe Kenji , Tsukamoto Masafumi , Shibuya Ryozo , Morimoto Hiroyuki , Ohshima Takashi 
Published: January 2015

AbstractAn increased supply of scarce or inaccessible natural products is essential for the development of more sophisticated pharmaceutical agents and biological tools, and thus the development of atom‐economical, step‐economical and scalable processes to access these natural products is in high demand. Herein we report the development of a short, scalable total synthesis of (−)‐α‐kainic acid, a useful compound in neuropharmacology that is, however, limited in supply from natural resources. The synthesis features sequential platinum‐catalyzed direct allylic aminations and thermal ene‐cyclization, enabling the gram‐scale synthesis of (−)‐α‐kainic acid in six steps and 34 % overall yield.
Environmental Transmission Electron Microscopy Study of Diesel Carbon Soot Combustion under Simulated Catalytic‐Reaction Conditions
Authors: Mori Kohsuke , Watanabe Keitaro , Sato Takeshi , Yamashita Hiromi 
Published: January 2015

AbstractEnvironmental transmission electron microscopy (ETEM) is used to monitor the catalytic combustion of diesel carbon soot upon exposure to molecular oxygen at elevated temperatures by using a gas‐injection specimen heating holder. The reaction conditions simulated in the ETEM experiments reconstruct real conditions effectively. This study demonstrated for the first time that soot combustion occurs at the soot–catalyst interface for both Ag/CeO2 and Cu/BaO/La2O3 catalysts.
Thermally Stable Positive Electrolytes with a Superior Performance in All‐Vanadium Redox Flow Batteries
Authors: Flox Cristina , Rubio‐Garcia Javier , Skoumal Marcel , Vázquez‐Galván Javier , Ventosa Edgar , Morante Joan Ramon 
Published: January 2015

AbstractA new positive electrolyte formulation for all‐vanadium redox flow batteries (VFRB) with a significant improvement in electrochemical properties is reported in this communication. A 5 KDa poly(ethyleneimine)‐based dendrimer (dPEI) demonstrates enhanced performance when used as an additive for positive electrolytes in VFRB. A thermal stability test at 40 °C shows that the dPEI additive prevents the precipitation of VO2+ over 720 h. The optimum concentration of the dPEI additive was as low as 0.6 % (weight per volume of electrolyte), leading to a cost‐effective solution in terms of a 38 % increase in energy density (18 Wh L−1) with respect to the additive‐free system (ca. 13 Wh L−1). Moreover, this innovative electrolyte performance remains stable at 88 % in energy efficiency over a wider operational temperature (up to 60 °C) while retaining the energy density.
Tin‐containing Silicates: Alkali Salts Improve Methyl Lactate Yield from Sugars
Authors: Tolborg Søren , Sádaba Irantzu , Osmundsen Christian M. , Fristrup Peter , Holm Martin S. , Taarning Esben 
Published: January 2015

AbstractThis study focuses on increasing the selectivity to methyl lactate from sugars using stannosilicates as heterogeneous catalyst. All group I ions are found to have a promoting effect on the resulting methyl lactate yield. Besides, the alkali ions can be added both during the preparation of the catalyst or directly to the solvent mixture to achieve the highest reported yield of methyl lactate (ca. 75 %) from sucrose at 170 °C in methanol. The beneficial effect of adding alkali to the reaction media applies not only to highly defect‐free Sn‐Beta prepared through the fluoride route, but also to materials prepared by post‐treatment of dealuminated commercial Beta zeolites, as well as ordered mesoporous stannosilicates, in this case Sn‐MCM‐41 and Sn‐SBA‐15. These findings open the door to the possibility of using other preparation methods or different Sn‐containing silicates with equally high methyl lactate yields as Sn‐Beta.