bluuebunny/crossref_metadata_2025_split huggingface dataset:
Design und enantioselektive Synthese von Cashmeran‐Riechstoffen mithilfe der “Enol‐Katalyse”
Authors: Felker Irene , Pupo Gabriele , Kraft Philip , List Benjamin 
Published: January 2015

AbstractDurch Überlagerungsanalysen wurden neue Cashmeran‐Riechstoffe entworfen, deren kurze Synthesen auf einer neuartigen Brønsted‐Säure‐katalysierten asymmetrischen Michael‐Addition von nichtaktivierten α‐substituierten Ketonen beruht. Dieser Schlüsselschritt wurde durch eine neue Art der Enol‐Aktivierungskatalyse realisiert, die unterschiedliche cyclische Ketone mit α‐quartären Stereozentrum in guten bis sehr guten Ausbeuten und mit hohen Enantioselektivitäten zugänglich macht. Die enantiomerenreinen Zielstrukturen wurden durch anschließende McMurry‐Kupplung und Saegusa‐Ito‐Oxidation hergestellt. Ein Enantiomer hat tatsächlich die typischen Geruchscharakteristika von Cashmeran.
Ratiometric Fluorescence Imaging of Cellular Polarity: Decrease in Mitochondrial Polarity in Cancer Cells
Authors: Jiang Na , Fan Jiangli , Xu Feng , Peng Xiaojun , Mu Huiying , Wang Jingyun , Xiong Xiaoqing 
Published: January 2015

AbstractMitochondrial polarity strongly influences the intracellular transportation of proteins and interactions between biomacromolecules. The first fluorescent probe capable of the ratiometric imaging of mitochondrial polarity is reported. The probe, termed BOB, has two absorption maxima (λabs=426 and 561 nm) and two emission maxima—a strong green emission (λem=467 nm) and a weak red emission (642 nm in methanol)—when excited at 405 nm. However, only the green emission is markedly sensitive to polarity changes, thus providing a ratiometric fluorescence response with a good linear relationship in both extensive and narrow ranges of solution polarity. BOB possesses high specificity to mitochondria (Rr=0.96) that is independent of the mitochondrial membrane potential. The mitochondrial polarity in cancer cells was found to be lower than that of normal cells by ratiometric fluorescence imaging with BOB. The difference in mitochondrial polarity might be used to distinguish cancer cells from normal cells.
Antibody Activation using DNA‐Based Logic Gates
Authors: Janssen Brian M. G. , van Rosmalen Martijn , van Beek Lotte , Merkx Maarten 
Published: January 2015

AbstractOligonucleotide‐based molecular circuits offer the exciting possibility to introduce autonomous signal processing in biomedicine, synthetic biology, and molecular diagnostics. Here we introduce bivalent peptide–DNA conjugates as generic, noncovalent, and easily applicable molecular locks that allow the control of antibody activity using toehold‐mediated strand displacement reactions. Employing yeast as a cellular model system, reversible control of antibody targeting is demonstrated with low nM concentrations of peptide–DNA locks and oligonucleotide displacer strands. Introduction of two different toehold strands on the peptide–DNA lock allowed signal integration of two different inputs, yielding logic OR‐ and AND‐gates. The range of molecular inputs could be further extended to protein‐based triggers by using protein‐binding aptamers.
Design and Enantioselective Synthesis of Cashmeran Odorants by Using “Enol Catalysis”
Authors: Felker Irene , Pupo Gabriele , Kraft Philip , List Benjamin 
Published: January 2015

AbstractNovel Cashmeran odorants were designed by molecular modeling. Their short syntheses involve a novel asymmetric Brønsted acid catalyzed Michael addition of unactivated α‐substituted ketones. This key transformation was realized by utilizing a new type of enol activation catalysis and affords different cyclic ketones bearing α‐quaternary stereocenters in good to excellent yields and with high enantioselectivity. Subsequent McMurry coupling and Saegusa–Ito oxidation furnished the enantiopure target odorants, one enantiomer of which indeed possesses the typical olfactory aspects of Cashmeran.
Ba3P5N10Br:Eu2+: A Natural‐White‐Light Single Emitter with a Zeolite Structure Type
Authors: Marchuk Alexey , Schnick Wolfgang 
Published: January 2015

AbstractIllumination sources based on phosphor‐converted light emitting diode (pcLED) technology are nowadays of great relevance. In particular, illumination‐grade pcLEDs are attracting increasing attention. Regarding this, the application of a single warm‐white‐emitting phosphor could be of great advantage. Herein, we report the synthesis of a novel nitridophosphate zeolite Ba3P5N10Br:Eu2+. Upon excitation by near‐UV light, natural‐white‐light luminescence was detected. The synthesis of Ba3P5N10Br:Eu2+ was carried out using the multianvil technique. The crystal structure of Ba3P5N10Br:Eu2+ was solved and refined by single‐crystal X‐ray diffraction analysis and confirmed by Rietveld refinement and FTIR spectroscopy. Furthermore, spectroscopic luminescence measurements were performed. Through the synthesis of Ba3P5N10Br:Eu2+, we have shown the great potential of nitridophosphate zeolites to serve as high‐performance luminescence materials.
Mechanical characterization of high‐performance graphene oxide incorporated aligned fibroporous poly(carbonate urethane) membrane for potential biomedical applications
Authors: Thampi Sudhin , Muthuvijayan Vignesh , Parameswaran Ramesh 
Published: January 2015

ABSTRACTIn this article, we report the development of graphene oxide (GO) reinforced electrospun poly(carbonate urethane) (PCU) nanocomposite membranes intended for biomedical applications. In this study, we aimed to improve the mechanical properties of PCU fibroporous electrospun membranes through fiber alignment and GO incorporation. Membranes with 1, 1.5, and 3% loadings of GO were evaluated for their morphology, mechanical properties, crystallinity, biocompatibility, and hemocompatibility. The mechanical properties were assessed under both static and dynamic conditions to explore the tensile characteristics and viscoelastic properties. The results show that GO presented a good dispersion and exfoliation in the PCU matrix, contributing to an increase in the mechanical performance. The static mechanical properties indicated a 55% increase in the tensile strength, a 127% increase in toughness for 1.5 wt % GO loading and the achievement of a maximum strength reinforcement efficiency value at the same loading. Crystallinity changes in membranes were examined by X‐ray diffraction analysis. In vitro cytotoxicity tests with L‐929 fibroblast cells and percentage hemolysis tests with fresh venous blood displayed the membranes to be cytocompatible with acceptable levels of hemolytic characteristics. Accordingly, these results highlight the potential of this mechanically improved composite membrane's application in the biomedical field. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41809.
Improving properties of ceramic silicone rubber composites using high vinyl silicone oil
Authors: Cao Erping , Cui Xiaoqian , Wang Kai , Li Yinyin , Guo Weihong 
Published: January 2015

ABSTRACTReactive high vinyl silicone oil (HVSO) was selected to prepare the ceramic silicone rubber composites. The effects of HVSO on the mechanical properties and thermal stabilities of ceramic silicone rubber composites were investigated. The structures of the cross‐linked network of silicone rubber with or without HVSO were studied. The intermolecular space of silicone rubber was enlarged, and the cross‐linked point was concentrated by addition of HVSO, which was demonstrated by cross‐linking densities, scanning electron microscope (SEM) images, and dynamic mechanical analysis (DMA). The cross‐linked network model was formed with the slipping of the cross‐linked points along with the silicone rubber chain. Mechanical properties of composites were enhanced by the formation of this cross‐linked network. The tear strength, tensile strength, and elongation at break of the composites were increased by 18.5%, 13.2%, and 37.4% by the adding of 2 phr HVSO, respectively. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41864.
Bioactive polymeric nanofiber matrices for skin regeneration
Authors: Guadalupe Eross , Ramos Daisy , Shelke Namdev B. , James Roshan , Gibney Christian , Kumbar Sangamesh G. 
Published: January 2015

ABSTRACTElectrospun nanofiber matrices have attracted a great deal of attention as matrices for skin repair and regeneration. The current manuscript reports the fabrication and characterization of a bioactive polycaprolactone (PCL) fiber matrix for its ability to deliver multiple factors. Bioactive PCL matrices were created by incorporating a model angiogenic factor and a model antibiotic drug. Chitosan coating on the fiber matrices significantly improved the ability to hold moisture and contributed to antibiotic activity. These fiber matrices have a modulus of 5.8 ± 1.3 MPa and matrices subjected to degradation over 4 weeks did not lose their tensile properties due to slow degradation rate. Chitosan coating avoided the initial burst release commonly associated with fiber matrices and only 60% of the encapsulated drug was released over a period of 15 days. Control PCL‐chitosan matrices were able to reduceStaphylococcus aureus(S. aureus) growth both in static and dynamic condition as compared to formulations with 50 mg gentamicin. In general, all the fiber matrices were able to support fibroblast growth and maintained normal cell morphology. Such bioactive bandages may serve as versatile and less expensive alternatives for the treatment of complex wounds. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2015,132, 41879.
Swelling kinetics, mechanical properties, and release characteristics of chitosan‐based semi‐IPN hydrogels
Authors: Özbaş Zehra , Gürdağ Gülten 
Published: January 2015

ABSTRACTTwo series of pH‐sensitive semi‐interpenetrating network hydrogels (semi‐IPN) based on chitosan (CS) natural polymer and acrylamide (AAm) and/or N‐hydroxymethyl acrylamide (HMA) monomers by varying the monomer and CS ratios were synthesized by free radical chain polymerization. 5‐Fluorouracil (5‐FU), a model anticancer drug, has been added to the feed composition before the polymerization. The characterization of gels indicated that the drug is molecularly dispersed in the polymer matrix. The swelling kinetics of drug‐loaded gels have decreased with increased HMA content at 37°C in both distilled water and buffer solutions with a pH of 2.1 or 7.4. Elastic modulus of the gels increased with the increase in HMA content and higher CS concentration enhanced the elastic modulus positively. Moreover, cumulative release percentages of the gels for 5‐FU were ca. 10% higher in pH 2.1 than those in pH 7.4 media. It was determined that they can be suitable for the use in both gastric and colon environments. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41886.
Bemessungsdiagramme für den biegebeanspruchten Stab im Holzbau
Authors: Moosbrugger Thomas , Krenn Harald , Bogensperger Thomas 
Published: January 2015

AbstractIm vorliegenden Aufsatz werden Bemessungstafeln zur Vorbemessung von Bauteilen aus Holz – Ermittlung der erforderlichen Querschnittshöhe – in Abhängigkeit definierter Eingangsparameter (Einwirkungen, Geometrie, Systemdefinitionen, Materialeigenschaften) vorgestellt. Eine allgemeingültige Aussage, welcher ULS‐ bzw. SLS‐Nachweis die relevante Bemessungssituation für die Dimensionierung eines Bauteiles widerspiegelt, kann aufgrund der Vielzahl an Einflussparametern, wie z. B. der Materialkennwerte, der Trägerspannweite und der Belastung, a priori nicht eindeutig getätigt werden. Für die effiziente Vorbemessung gemäß ÖNORM EN 1995‐1‐1 [1] liegen bis dato keinerlei nutzbare Bemessungsdiagramme für biegebeanspruchte Stäbe mit wissenschaftlicher Aussagekraft vor.Design charts for a single spanned timber beam under bending – Part 1: Roof beam with a homogeneous rectangular beam cross‐sectionIn the presented paper design charts for the preliminary design of components made of timber (determination of the required cross‐sectional height) are shown. The charts are given as functions of several defined input parameters like loads, system geometry and material behavior. A generally valid statement, which kind of verification (ULS or SLS) reflects the relevant design situation for the design of a timber component is not possible. This may occur due to numerous influencing parameters. Currently no design charts for the efficient preliminary design according to ÖNORM EN 1995‐1‐1 [1] are available.
Buchenfurnierschichtholz für Fachwerkträger und verstärktes Brettschichtholz
Authors: Enders‐Comberg Markus , Frese Matthias , Blaß Hans Joachim 
Published: January 2015

AbstractMit Buchenfurnierschichtholz (Buchen‐FSH) gibt es für den Ingenieurholzbau seit einem Jahr einen neuen Holzwerkstoff. In Abhängigkeit von der Ausrichtung der Schälfurniere in der geschichteten Struktur sind charakteristische Zugfestigkeiten von bis zu 70 N/mm2 in Haupt‐ und bis zu 17 N/mm2 in Querrichtung bauaufsichtlich festgelegt. Ein Material mit diesen Festigkeitswerten eröffnet neue konstruktive Möglichkeiten. Der Aufsatz berichtet über gezielte Untersuchungen an Anschlüssen für Fachwerkträger aus Buchen‐FSH und Verstärkungen von Fichtenbrettschichtholz mit keilgezinkten Lamellen aus Buchen‐FSH. Die Ergebnisse zeigen, dass bei Fachwerkträgern die überdurchschnittlich hohen Materialfestigkeiten aufgrund der limitierenden Wirkung von Anschlusstragfähigkeiten fallweise nicht voll ausgenutzt werden können. Es bleibt Raum für die Entwicklung von leistungsfähigen FSH‐spezifischen Anschlusslösungen. In der Funktion als Verstärkung für Brettschichtholz können Buchen‐FSH‐Lamellen zu einer signifikanten Steigerung der Biegefestigkeit beitragen. Experimentelle Nachweise hierzu stehen noch aus.Beech LVL for trusses and reinforced glulamBeech LVL is an engineered wood product for timber structures; it is available for one year. Depending on the orientation of the veneers in the material, characteristic tensile strengths of up to 70 N/mm2 in main and 17 N/mm2 in transversal direction are defined in the corresponding technical approval. A material having such strength properties opens new structural possibilities. The paper reports purposive investigations on joints for truss girders made of beech LVL and on glulam reinforcements made of finger jointed beech LVL laminations. Regarding truss girders, the results demonstrate that the high material strengths cannot always be used due to the limiting effect of the joint capacities. Hence, opportunities remain for the development of efficient LVL specific joint solutions. Beech LVL laminations as glulam reinforcement may contribute to a significant strength increase. However, corresponding experimental verifications are still pending.
Kunstharzpressholz zur Verstärkung von Brettschichtholz
Authors: Haller Peer , Heiduschke Andreas , Putzger Robert , Hartig Jens 
Published: January 2015

AbstractEs wurden Biegeträger aus Brettschichtholz (BSH) untersucht, die zur Erhöhung der Tragfähigkeit und der Dauerhaftigkeit auf der Zug‐ und wahlweise auf der Druckseite mit Kunstharzpressholz (KHP) verstärkt wurden. KHP ist ein Holzwerkstoff, der aus phenolharzgetränkten Furnieren der Rotbuche (Fagus sylvatica) besteht. KHP weist einen Elastizitätsmodul von über 20000 N/mm2 und eine Biegefestigkeit von 200 N/mm2 auf, was gegenüber den entsprechenden Werten von BSH GL24h eine Verdopplung bzw. Verdreifachung bedeutet. Die Verstärkung von Biegeträgern aus GL24h erbrachte bei sonst gleichen Querschnitten mehr als eine Verdopplung der Tragfähigkeit; die Steifigkeit erhöhte sich um etwa ein Drittel. Außerdem wurde der Verbund zwischen BSH und KHP abwechselnd befeuchtet und getrocknet, um die Dauerhaftigkeit zu testen. Teilweise getränktes KHP nahm viel Feuchtigkeit auf und quoll stark, jedoch weniger als unbehandelte Rotbuche. Dieser Werkstoff ist daher nur für die Nutzungsklassen 1 und 2 geeignet. Vollständig getränktes KHP hingegen nahm kaum Feuchtigkeit auf und quoll nur wenig, sodass es sich ebenso für die Nutzungsklasse 3 empfiehlt.Compressed laminated wood for the strengthening of glued laminated timberGlued laminated timber girders were investigated, which were strengthened with compressed laminated wood at the tension lamella and optionally also at the compression lamella to increase load‐bearing capacity and stiffness. Compressed laminated wood is a wood composite consisting of beech (Fagus sylvatica) veneers, which are impregnated with phenol‐resorcin resin. Compressed laminated wood possesses a YOUNG's modulus of more than 20000 N/mm2 and a bending strength of more than 200 N/mm2, which is compared to glued laminated timber GL24h a doubling and a tripling, respectively. The strengthening of the GL24h girders with compressed laminated wood led to a doubling of the bending capacity and to an increase of stiffness of about one third compared to plain GL24h girders with the same cross section. Moreover, the joint of glued laminated timber and compressed laminated wood was exposed to wetting‐drying cycles to investigate the durability. Partly impregnated compressed laminated wood absorbed a lot of moisture and swelled heavily, but still less than plain beech wood. Thus, this material is only recommendable for the service classes 1 and 2. Completely impregnated compressed laminated wood showed only very low moisture uptake and swelling and can be applied also in service class 3.
Formholzrohre aus Buche
Authors: Haller Peer , Hartig Jens , Wehsener Jörg 
Published: January 2015

AbstractDie tragende Verwendung der Buche (Fagus sylvatica) wird gegenwärtig in den deutschsprachigen Ländern intensiv erforscht. Der Grund dafür ist der große, weitgehend ungenutzte Buchenbestand, der im Zuge des Waldumbaus zu Lasten der Fichte (Picea abies) weiter wachsen wird. Heute hängt die Wertschöpfungskette der Forst‐ und Holzwirtschaft zu 90 % am Nadelbaum. Fast zwei Drittel davon entfallen auf den Bau. Die Struktur der Wälder wird sich in Zukunft ändern und die Industrie vor die Aufgabe stellen, der Ressourcenveränderung mit neuen Verfahren und Produkten zu begegnen. Ein Beispiel dafür ist das Formholzrohr. Dieser Beitrag untersucht das Tragverhalten solcher Rohre, die nach einem speziellen Verfahren aus massiven Platten gerollt wurden.Molded wooden tubes made of beechThe structural use of beech (Fagus sylvatica) is currently under intensive investigation in the German‐speaking countries. The reason is the large, widely unused stock in the forests, which will further increase at the burden of spruce (Picea abies) due to the forest conversion. Today, the value added chain of the forest and timber economy depends to 90 % on softwood. Almost two third thereof are used for the building industry. The structure of the forests will change in the future and it is the task of the industry to react with new methods and products. An example is the molded wooden tube. This contribution investigates the load‐bearing behavior of such tubes, which are rolled out of massive timber board following a special technique.
Mindestnutzhöhen von Stahlbetonplatten für l/250 und l/500
Authors: Jeromin Wolf 
Published: January 2015

AbstractDie statische Nutzhöhe und damit die Querschnittshöhe wird bei Stahlbetonplatten durch Begrenzung der Bauteildurchbiegung bestimmt. Diese Begrenzung ist zur Vermeidung von Schäden infolge zu großen Deckendurchhangs oder in nicht tragenden Wänden erforderlich. Sie erfolgt durch geometrische Kriterien (zulässige Biegeschlankheiten) ohne direkte Berechnung. Sie sind in DIN 1045‐1 [1] und Eurocode 2 [2] unterschiedlich groß angegeben und erfüllen die dort ebenfalls als Grenzwerte angegebenen Durchbiegungswerte von l/250 und l/500 nicht. Überdies werden zweiachsig gespannte Platten trotz deutlich geringerer Beanspruchung hinsichtlich der Biegeschlankheit wie einachsig gespannte behandelt. Um diese Differenzen aufzuheben, werden für die Durchbiegungswerte von l/250 und l/500 ein Lösungsweg, Gleichungen für die Nutzhöhe und Diagramme vorgestellt, die für ein‐ und zweiachsige Tragwirkung für starre und elastische Linienlagerung sowie Punktstützung gelten.Minimum useful heights of reinforced concrete for l/250 and l/500The static useful height and hence the cross‐sectional height of reinforced concrete slabs is determined by limiting the component sag. This restriction is necessary in order to prevent damage due to excessive sagging of the floor or in non‐constructional walls. It is based on geometrical criteria (permitted flexural slenderness values) without direct calculation. The values stated in DIN 1045‐1 [1] and Eurocode 2 [2] are of different magnitudes and do not comply with the limit values of l/250 and l/500 which are likewise stipulated there for the sag. Moreover, despite their distinctly lower stress and strain, slabs with biaxial stress are treated in the same way as slabs with uniaxial stress where flexural slenderness is concerned. To eliminate these differences, a suitable solution is presented for a sag of l/250 and l/500, with equations for useful heights and diagrams which are valid for both rigid and elastic linear support as well as point support in uniaxial and biaxial structural conditions.
Einfluss der Nachbehandlung auf das Karbonatisierungsverhalten von Beton aus klinkerarmen Zementen
Authors: Hainer Stefan , Proske Tilo , Graubner Carl‐Alexander 
Published: January 2015

AbstractDie Dauerhaftigkeit von Betonbauteilen wird wesentlich durch die Nachbehandlung beeinflusst. Die erforderliche Nachbehandlungsdauer von Betonbauteilen ist normativ durch die Expositionsklasse und die Festigkeitsentwicklung des Betons determiniert. Der vorliegende Beitrag befasst sich mit dem Einfluss der Nachbehandlung auf die Druckfestigkeit und die Karbonatisierungstiefe von Betonen aus Zementen mit niedrigem Klinkergehalt.Im Rahmen experimenteller Untersuchungen wurden sowohl der Einfluss der Nachbehandlungsdauer als auch die Auswirkungen variierender Umgebungsbedingungen und einer nachträglichen Befeuchtung auf die Betoneigenschaften analysiert. Weiterhin erfolgte ein Vergleich der Versuchsergebnisse mit bekannten Vorhersagemodellen zum Einfluss der Nachbehandlungsdauer sowie der Umgebungsbedingungen auf die Karbonatisierungstiefe. Abschließend wird eine Bewertung der in DIN 1045‐3 [1] festgelegten Mindestdauer der Nachbehandlung vorgenommen.Influence of curing on the carbonation of clinker‐reduced concretesThe durability of concrete structures is significantly influenced by the curing conditions. The normative required curing time of concrete elements is determined by the exposure class and the strength development of the concrete. This article deals with the influence of curing on the compressive strength and the carbonation depth of concretes with low clinker cements.As part of the experimental investigations, both the influence of the curing time and the effects of varying environmental conditions and a subsequent moistening on the concrete properties were analyzed. Furthermore, a comparison of the results with known prediction models on the influence of curing time and environmental conditions on the carbonation depth was carried out. Subsequently an evaluation of the required minimum curing time according to DIN 1045‐3 [1] was conducted.