bluuebunny/crossref_metadata_2025 huggingface dataset:
Water table salinization due to seawater intrusion
Authors: Badaruddin Sugiarto , Werner Adrian D. , Morgan Leanne K.
Published: October 2015

Seawater intrusion (SWI) is a significant threat to freshwater resources in coastal aquifers around the world. Previous studies have focused on SWI impacts involving salinization of the lower domain of coastal aquifers. However, under certain conditions, SWI may cause salinization of the entire saturated zone of the aquifer, leading to water table salinization (WTS) in unconfined aquifers by replacing freshwater within the upper region of the saturated zone with seawater, thereby posing a salinity threat to the overlying soil zone. There is presently limited guidance on the extent to which WTS may occur as a secondary impact of SWI. In this study, physical experiments and numerical modeling were used to explore WTS associated with SWI in various nontidal, unconfined coastal aquifer settings. Laboratory experiments and corresponding numerical simulations show that significant WTS can occur under active SWI (i.e., the freshwater hydraulic gradient slopes toward the land) because the cessation of freshwater discharge to the sea and the subsequent landward flow across the entire sea boundary eventually lead to water table salinities approaching seawater concentration. WTS during active SWI is larger under conditions of high hydraulic conductivity, rapid SWI, high dispersivity and for deeper aquifers. Numerical modeling of four published field cases demonstrates that rates of WTS of up to 60 m/yr are plausible. Under passive SWI (i.e., the hydraulic gradient slopes toward the sea), minor WTS may arise as a result of dispersive processes under certain conditions (i.e., high dispersivity and hydraulic conductivity, and low freshwater discharge). Our results show that WTS is probably widespread in coastal aquifers experiencing considerable groundwater decline sustained over several years, although further evidence is needed to identify WTS under field settings.
A Novel Hybrid‐Structured Titanium Surface Promotes Adhesion of Human Dermal Fibroblasts and Osteogenesis of Human Mesenchymal Stem Cells while Reducing S. epidermidis Biofilm Accumulation
Authors: Park Byung‐Wook , Krieger Jessica , Sondag Gregory R. , Moussa Fouad M. , Rankenberg Johanna , Safadi Fayez F. , Gatsonis Nikolaos A. , McGimpsey W. Grant , Lambert Christopher R. , Malcuit Christopher
Published: October 2015

We provide a comparative analysis of protein adsorption, primary human cell behavior, and biofilm formation on modified titanium substrates of either micro‐, nano‐, or hybrid micro/nano‐scale feature sizes. While studies revealed that nano‐scale structures initially decreased the attachment and spreading of both human fibroblasts (hDFs) and mesenchymal stem cells (hMSCs), hMSC differentiation studies revealed that hybrid structures promoted the highest levels of osteogenic gene expression and attenuated biofilm formation by Staphylococcus epidermidis. Taken together, this novel approach of generating a hybrid topographical feature results in a potential implant material capable of enhanced dermal cell adhesion and osteogenic differentiation while limiting biofilm accumulation.
Tuning Crystal Ordering, Electronic Structure, and Morphology in Organic Semiconductors: Tetrathiafulvalenes as a Model Case
Authors: Pfattner Raphael , Bromley Stefan T. , Rovira Concepció , Mas‐Torrent Marta
Published: October 2015

Tetrathiafulvalenes (TTFs) are an appealing class of organic small molecules giving rise to some of the highest performing active materials reported for organic field effect transistors (OFETs). Because they can be easily chemically modified, TTF‐derivatives are ideal candidates to perform molecule–property correlation studies and, especially, to elucidate the impact of molecular and crystal engineering on device performance. A brief introduction into the state‐of‐the‐art of the field‐effect mobility values achieved with TTF derivatives employing different fabrication techniques is provided. Following, structure–performance relationships are discussed, including polymorphism, a phenomenon which is crucial to control for ensuring device reproducibility. It is also shown that chemical modification of TTFs has a strong influence on the electronic structure of these materials, affecting their stability as well as the nature of the generated charge carriers, leading to devices with p‐channel, n‐channel, or even ambipolar behaviour. TTFs have also shown promise in other applications, such as phototransistors, sensors, or as dopants or components of organic metal charge transfer salts used as source–drain contacts. Overall, TTFs are appealing building blocks in organic electronics, not only because they can be tailored to perform fundamental studies, but also because they offer a wide spectrum of potential applications.
Buckling Patterns of Graphene–Boron Nitride Alloy on Ru(0001)
Authors: Kutana Alex , Goriachko Andrii , Hu Zhili , Sachdev Hermann , Over Herbert , Yakobson Boris I.
Published: October 2015

Buckling nanopatterns of monoatomic layer 2D materials on metal substrates attract significant attention due to their rich interface morphology affecting electronic applications. An experimental–theoretical study of a 2D boron–nitrogen–carbon (B
x

/2N
x

/2C1−x
) alloy on a Ru(0001) surface is conducted and a profound relation between the composition x and the degree of buckling is discovered. Experimentally, real carbon–boron–nitrogen alloys on the Ru(0001) surface are demonstrated and various morphologies of pure and mixed compounds are shown. Density functional theory calculations are further carried out using the supercells of graphene, hexagonal boron nitride (h‐BN), and random BNC on Ru(0001), as well as Monte Carlo simulations for elucidating the kinetics of their growth. The results show that unlike pure compounds (h‐BN or C), the carbon–boron–nitrogen mix on Ru(0001) mostly exists in an uncorrugated form, thus greatly improving the interface contact. The likely cause of the diminished corrugation is a softening of bond angular interactions in the alloy relative to the pure phases.
Gelatin‐Immobilized High Aspect Ratio Gold Nanocrystals: An Efficient Catalyst for 4‐Nitrophenol Reduction
Authors: Sharma Shyamalima , Bora Pritom J , Boruah Monalisha , Dolui Swapan K
Published: October 2015

This article highlights the progress in the synthesis of gelatin‐immobilized anisotropic gold (Au) nanoparticles and their catalytic activity in 4‐nitrophenol (4‐NP) reduction. The catalytic process is monitored by using the UV–visible spectrophotometer, and the effect of shape and aspect ratio on the Au nanoparticles on catalytic activity is investigated. The catalytic process follows a pseudo–first‐order kinetics with the rate constant in the range of 1.1 × 10−3 s−1 to 4.5 × 10−3s−1. It is found that high aspect ratio Au/gelatin shows the best conversion (99.89%), which is comparable to the spherical seed (99.93%). After a certain catalytic reaction, the recovery of expensive catalysts and their reuse without losing their activity is an essential element in the sustainable process development. The immobilization of the catalyst into gelatin allows the high aspect ratio Au/gelatin nanocatalyst to be recovered and reused for a number of cycles.
Development of Active Organic and Polymeric Materials for Batteries and Solar Cells: Introduction to Essential Characterization Techniques
Authors: Friebe Christian , Schubert Ulrich S.
Published: October 2015

Establishing renewable energy sources is currently one of the major scientific topics. Two aspects are most crucial: energy conversion and energy storage. Thus, the development of efficient solar‐cell devices and high‐capacity, high‐current rechargeable battery systems turns out to be of great importance. In particular, the design of active materials and their characterization using electrochemical and spectroscopic means represent essential elements in the development process. Here, a concise overview of both methods and key properties with regard to the characterization of organic and polymeric active materials with a focus on energy conversion/storage is provided. Benefits and limitations of complementary techniques are presented to enable a consistent and comprehensive characterization procedure.
Comparative study of reproductive skew and pair‐bond stability using genealogies from 80 small‐scale human societies
Authors: Ellsworth Ryan M. , Shenk Mary K. , Bailey Drew H. , Walker Robert S.
Published: October 2015

Objectives

Genealogies contain information on the prevalence of different sibling types that result from past reproductive behavior. Full sibling sets stem from stable monogamy, paternal half siblings primarily indicate male reproductive skew, and maternal half siblings reflect unstable pair bonds.

Methods

Full and half sibling types are calculated for a total of 61,181 siblings from published genealogies for 80 small‐scale societies, including foragers, horticulturalists, agriculturalists, and pastoralists from around the world.

Results

Most siblings are full (61%) followed by paternal half siblings (27%) and maternal half siblings (13%). Paternal half siblings are positively correlated with more polygynous marriages, higher at low latitudes, and slightly higher in nonforagers, Maternal half sibling fractions are slightly higher at low latitudes but do not vary with subsistence. Partible paternity societies in Amazonia have more paternal half siblings indicating higher male reproductive skew.

Conclusions

Sibling counts from genealogies provide a convenient method to simultaneously investigate the reproductive skew and pair‐bond stability dimensions of human mating systems cross‐culturally. Am. J. Hum. Biol. 28:335–342, 2016. © 2015 Wiley Periodicals, Inc.
Dust in the wind: How climate variables and volcanic dust affect rates of tooth wear in central american howling monkeys
Authors: Spradley Jackson P. , Glander Kenneth E. , Kay Richard F.
Published: October 2015

Objectives

Two factors have been considered important contributors to tooth wear: dietary abrasives in plant foods themselves and mineral particles adhering to ingested food. Each factor limits the functional life of teeth. Cross‐population studies of wear rates in a single species living in different habitats may point to the relative contributions of each factor.

Materials and Methods

We examine macroscopic dental wear in populations of Alouatta palliata (Gray, 1849) from Costa Rica (115 specimens), Panama (19), and Nicaragua (56). The sites differ in mean annual precipitation, with the Panamanian sites receiving more than twice the precipitation of those in Costa Rica or Nicaragua (∼3,500 mm vs. ∼1,500 mm). Additionally, many of the Nicaraguan specimens were collected downwind of active plinian volcanoes. Molar wear is expressed as the ratio of exposed dentin area to tooth area; premolar wear was scored using a ranking system.

Results

Despite substantial variation in environmental variables and the added presence of ash in some environments, molar wear rates do not differ significantly among the populations. Premolar wear, however, is greater in individuals collected downwind from active volcanoes compared with those living in environments that did not experience ash‐fall.

Discussion

Volcanic ash seems to be an important contributor to anterior tooth wear but less so in molar wear. That wear is not found uniformly across the tooth row may be related to malformation in the premolars due to fluorosis. A surge of fluoride accompanying the volcanic ash may differentially affect the premolars as the molars fully mineralize early in the life of Alouatta. Am J Phys Anthropol 159:210–222, 2016. © 2015 Wiley Periodicals, Inc.
Ein fluoreszierender Chlorophyll‐Katabolit des Dioxobilin‐Typs als transientes und frühes Zwischenprodukt des Dioxobilin‐Astes des Chlorophyllabbaus in Arabidopsis thaliana
Authors: Süssenbacher Iris , Hörtensteiner Stefan , Kräutler Bernhard
Published: October 2015

Der Chlorophyllabbau findet in höheren Pflanzen über den “PaO/Phyllobilin”‐Weg statt. Dabei werden zwei wichtige Phyllobilin‐Typen gebildet, die charakteristischen 1‐Formyl‐19‐oxobiline und die vor kurzem entdeckten 1,19‐Dioxobiline. Die hypothetische Verzweigung ist immer noch unbekannt, an welcher sich die ursprünglich gebildeten 1‐Formyl‐19‐oxobiline in 1,19‐Dioxobiline umwandeln. Hier klären wir diesen hypothetischen und entscheidenden Übergang durch die Identifizierung des ersten natürlichen fluoreszierenden Chlorophyll‐Kataboliten vom 1,19‐Dioxobilin‐Typ (DFCC) auf. Dieses kurzlebige Zwischenprodukt des Chlorophyllabbaus wurde aus Extrakten von Arabidopsis‐thaliana‐Blättern isoliert, die sich in einem frühen Seneszenz‐Stadium befanden. Dieser DFCC konnte als direkte Vorstufe des hauptsächlich entstehenden, nichtfluoreszierenden 1,19‐Dioxobilins identifiziert werden, das sich in seneszenten Blättern anreichert.
Die Synthese von B2(SIDip)2 und seine Reaktivität zwischen denen von Diboracumulenen und Diborinen
Authors: Böhnke Julian , Braunschweig Holger , Dellermann Theresa , Ewing William C. , Hammond Kai , Jimenez‐Halla J. Oscar C. , Kramer Thomas , Mies Jan
Published: October 2015

Eine neue Verbindung der Formel L‐B2‐L mit dem stabilisierenden Liganden (L) 1,3‐Bis(diisopropylphenyl)‐4,5‐dihydroimidazol‐2‐yliden (SIDip) wurde synthetisiert, isoliert und charakterisiert. Die π‐Acidität von SIDip liegt hierbei zwischen denen des wenig aciden 1,3‐Bis(diisopropylphenyl)imidazol‐2‐yliden(IDip)‐Liganden und des stark aciden CAAC‐Liganden 1‐(2,6‐Diisopropylphenyl)‐3,3,5,5‐tetramethylpyrrolidin‐2‐yliden und führt somit zu einem Molekül mit spektroskopischen, elektrochemischen und strukturellen Eigenschaften zwischen denen der durch CAAC oder IDip stabilisierten L‐B2‐L‐Verbindungen. Die Reaktion dieser drei Verbindungen mit CO verdeutlicht die Unterschiede. Während die π‐Acidität von CAAC oder SIDip zur Isolierung von Bis(boraketen)‐Verbindungen (L(OC)B‐B(CO)L) führt, konnte dies bei der Reaktion mit B2(IDip)2 nicht beobachtet werden. Im Unterschied dazu konnte lediglich mit B2(IDip)2 und B2(SIDip)2 eine Umsetzung zu bicyclischen Bis(boralacton)‐Verbindungen erreicht werden.
The HOMO Nodal Arrangement in Polychromophoric Molecules and Assemblies Controls the Interchromophoric Electronic Coupling
Authors: Talipov Marat R. , Navale Tushar S. , Rathore Rajendra
Published: October 2015

Triptycenes spontaneously assemble into two‐dimensional networks in which long‐range charge transport is facilitated by the extensive electronic coupling through the triptycene framework (intramolecularly) and by cofacial π‐stacking (intermolecularly). While designing and synthesizing next‐generation triptycenes containing polyaromatic chromophores, the electronic coupling amongst the chromophores was observed to be highly dependent on the nature and position of the substituents. Herein, we demonstrate using hexaalkoxytriptycenes that the electronic coupling amongst the chromophores is switched on and off by a simple repositioning of the substituents, which alters the nodal arrangement of the HOMOs of the individual chromophores. A visual inspection of the HOMOs can thus provide a ready evaluation of the electronic coupling in polychromophoric molecules/assemblies, and will serve as an important tool for the rational design of modern charge‐transport materials.
A Neutral Silicon/Phosphorus Frustrated Lewis Pair
Authors: Waerder Benedikt , Pieper Martin , Körte Leif A. , Kinder Timo A. , Mix Andreas , Neumann Beate , Stammler Hans‐Georg , Mitzel Norbert W.
Published: October 2015

Frustrated Lewis pairs (FLPs) have a great potential for activation of small molecules. Most known FLP systems are based on boron or aluminum atoms as acid functions, few on zinc, and only two on boron‐isoelectronic silicenium cation systems. The first FLP system based on a neutral silane, (C2F5)3SiCH2P(tBu)2 (1), was prepared from (C2F5)3SiCl with C2F5 groups of very high electronegativity and LiCH2P(tBu)2. 1 is capable of cleaving hydrogen, and adds CO2 and SO2. Hydrogen splitting was confirmed by H/D scrambling reactions. The structures of 1, its CO2 and SO2 adducts, and a decomposition product with CO2 were elucidated by X‐ray diffraction.
A Dioxobilin‐Type Fluorescent Chlorophyll Catabolite as a Transient Early Intermediate of the Dioxobilin‐Branch of Chlorophyll Breakdown in Arabidopsis thaliana
Authors: Süssenbacher Iris , Hörtensteiner Stefan , Kräutler Bernhard
Published: October 2015

Chlorophyll breakdown in higher plants occurs by the so called “PaO/phyllobilin” path. It generates two major types of phyllobilins, the characteristic 1‐formyl‐19‐oxobilins and the more recently discovered 1,19‐dioxobilins. The hypothetical branching point at which the original 1‐formyl‐19‐oxobilins are transformed into 1,19‐dioxobilins is still elusive. Here, we clarify this hypothetical crucial transition on the basis of the identification of the first natural 1,19‐dioxobilin‐type fluorescent chlorophyll catabolite (DFCC). This transient chlorophyll breakdown intermediate was isolated from leaf extracts of Arabidopsis thaliana at an early stage of senescence. The fleetingly existent DFCC was then shown to represent the direct precursor of the major nonfluorescent 1,19‐dioxobilin that accumulated in fully senescent leaves.
Untersuchung sicherheitsrelevanter Ablösungen von Fassadenelementen mit aktiver Thermografie
Authors: Maierhofer Christiane , Röllig Mathias , Steinfurth Henrik , Meinhardt Jeannine , Arnold Torsten
Published: October 2015

Die Bewertung des Zustandes und der Haftung von Putz und Fassadenelementen auf den darunterliegenden Bauwerksstrukturen ist eine häufig auftretende Fragestellung bei der Erhaltung und Instandsetzung von Bauwerken und Baudenkmälern. Hier müssen nicht nur wirtschaftliche und denkmalpflegerische, sondern auch sicherheitsrelevante Aspekte berücksichtigt werden. Fehlstellen und Ablösungen können, auch wiederholend, mit hoher Nachweisempfindlichkeit mit aktiven Thermografieverfahren geortet und unter bestimmten Voraussetzungen quantitativ bewertet werden. Dazu wird der zu untersuchende Bereich zunächst kurzzeitig (mehrere Minuten lang) erwärmt und anschließend die Abkühlung mit einer Infrarotkamera aufgezeichnet. Systematische Untersuchungen an Probekörpern mit einer Vielzahl unterschiedlicher Fehlstellen unterhalb von Kalkputz, Fliesen und Klinkerriemchen zeigen, dass die Fehlstellen sowohl mittels künstlicher Erwärmung durch einen Infrarotstrahler als auch mittels natürlicher Erwärmung durch die Sonne detektiert und charakterisiert werden können.

Inspection of safety relevant delaminations of façade elements using active thermography

The evaluation of condition and adhesion of plaster and façade elements to the underlying building structure is a common issue in the maintenance and repair of buildings and monuments. Here not only economic and preservation, but also safety relevant aspects have to be considered. Voids and delaminations can be detected repeatedly with high sensitivity using active thermography methods. Under certain conditions, also a quantitative evaluation is possible. The area under investigation has to be heated up for a short time (up to several minutes). Subsequently, the cooling down is recorded using an infrared camera. Systematic studies on test specimens with a variety of defects below lime plaster, tiles and brick tiles show that the defects can be detected and even characterized both by means of artificial heating using an infrared heater, as well as by natural solar heating.
Zerstörungsfreie Prüfung flammgespritzter Schutzschichten aus Glas für Beton – Erste Ergebnisse
Authors: Schulte Holthausen Robert , Thiele Swantje , Conradt Reinhard , Raupach Michael , Weichold Oliver
Published: October 2015

Im Rahmen einer Kooperation der Institute für Bauforschung (ibac) und Gesteinshüttenkunde (GHI) der RWTH Aachen University werden die Technik zur Applikation sowie die Eigenschaften von flammgespritzten, nahtlosen Glasschichten auf Beton untersucht. Besondere Herausforderungen ergeben sich hierbei aus der Differenz zwischen der maximal verträglichen Temperatur des Betons und der Temperatur des aufgeschmolzenen Glaspulvers wie auch des hohen pH‐Wertes der Beton‐Porenlösung und der Alkalienbeständigkeit des Glases. In aktuellen Versuchen wird der Einfluss des Flammspritzens auf die Eigenschaften der Glasschichten und des unterliegenden Betons untersucht. Hierbei werden Haftzugprüfungen des Schichtaufbaus der Glasschichten und optische Analysen kombiniert, um Rückschlüsse sowohl auf die Struktur und Undurchlässigkeit der Glasschichten als auch auf die thermische Schädigung des Betons zu ermöglichen. Es wird ein Messverfahren auf Basis einseitiger Kernspinresonanz eingeführt, das zukünftig zur Charakterisierung der Betonschädigung dienen soll, ohne hierfür die untersuchte Probe zerstörend prüfen zu müssen. Die Ergebnisse weisen darauf hin, dass die applikationsbedingte thermische Schädigung des Betons zu einer teils stark verringerten Haftung der gespritzten Glasschichten führt. Diese Schädigung kann des Weiteren zerstörungsfrei mittels Kernspinresonanz qualitativ geprüft werden. Verschiedene Lösungsansätze zur Erzielung einer ausreichenden Haftung werden derzeit untersucht.

Non‐destructive testing of seamless glass coatings on concrete applied by flamespraying – Preliminary results

As part of a research project at the Institutes of Building Materials Research (ibac) and Mineral Engineering (GHI) of RWTH Aachen University, a new application method by flame spraying for seamless glass coatings for the protection of concrete surfaces is being developed. A major challenge is the difference between the temperature resistance of concrete and the temperatures, necessary to melt glass powder. As part of the on‐going work, the influence of the flame spaying technique on the concrete surfaces and the applied glass coating are investigated. Adhesion testing and microscopic imaging are combined to gain information on the concrete damage and the glass coatings structure. By using single‐sided nuclear magnetic resonance, these properties are evaluated non‐destructively as well. Results show that the application process so far leads to severe damage in the concretes surface, resulting in low adhesion. Similar information can be gained non‐destructively by single‐sided nuclear magnetic resonance.
Auswirkungen von Unebenheiten bei trockenen Druckverbindungen von Betonbauteilen
Authors: Theiler Werner , Reicht Oliver , Tue Nguyen Viet
Published: October 2015

Hochfeste und ultrahochfeste Betone werden häufig in modularen Konstruktionen eingesetzt. Durch eine trockene Fuge kann der Bauablauf beschleunigt und dadurch die Wirtschaftlichkeit eines Projekts gesteigert werden. Durch Ungenauigkeiten in solchen Stoßfugen erfährt die Konstruktion zusätzliche Beanspruchungen. Anhand der Beispiele von ebenen Wandscheiben und Kreisringelementen wird der Einfluss von imperfekten glatten trockenen Fugen auf die Spannungsverteilung und ‐entwicklung im Bauteil diskutiert. Als Belastung wird eine gleichmäßig verteilte Druckspannung quer zur Stoßfuge im Regelbereich der Bauteile berücksichtigt. In der Praxis ist dieser Lastfall bei modularen Konstruktionen meist durch Vorspannung gegeben. Um das Verhalten der Bauteile unter solchen Randbedingungen beschreiben zu können, wurden FEM‐Berechnungen angestellt. Die Darstellung ausgewählter Ergebnisse zeigt, dass allgemeine Aussagen zum Verhalten solcher Fügungen nicht möglich sind. Für eine Beurteilung des Effekts von Unebenheiten in glatten trockenen Fugen muss der Sachverhalt auf eine konkrete Aufgabenstellung beschränkt werden.

Imperfect Plane Dry Joints under Pressure

High performance and ultra‐high performance concrete are commonly used in modular constructions. By using dry joints the construction progress can be accelerated. Thus the project can be more efficient. Due to unevenness in plane dry joints additional stress occurs. On the example of wall panels and circular ring shaped elements the effect on stress distribution and stress development in the concrete member because of plane dry joints with undulations are discussed. The elements are loaded by a uniform distributed compressive stress in the undisturbed regions perpendicular to the joint. This is a common load case due to prestressing in modular constructions. To discuss the behavior of concrete members under such conditions a FEM simulation is used. On specific results it is shown that no general statement can be done for such uneven connections. The effect of imperfect plane dry joints can only be assessed on case studies.
Untersuchungen zum Ermüdungsverhalten eines höherfesten Normalbetons
Authors: von der Haar Christoph , Hümme Julian , Marx Steffen , Lohaus Ludger
Published: October 2015

Die Betonermüdung gewinnt vor dem Hintergrund stetiger Weiterentwicklung im Betonbau neue Relevanz. Moderne Betone erreichen immer höhere Festigkeiten, wodurch die Betonbauweise an Attraktivität für neue Einsatzgebiete, wie Onshore‐ und Offshore‐Windenergieanlagen, gewinnt. Die Betonermüdung hat für diese zyklisch belasteten Konstruktionen eine besondere Bedeutung. Die Kenntnis von Bruchlastwechselzahlen ist für die Auslegung solcher Konstruktionen nicht mehr ausreichend. Es ergeben sich weiterführende Fragestellungen zur Dehnungs‐ und Steifigkeitsentwicklung und zu kombinierter Beanspruchung aus Ermüdungsbelastung und maritimen Umgebungsbedingungen, die mithilfe neuer Untersuchungsmethoden im Rahmen des Forschungsprojekts “ProBeton” an der Leibniz Universität Hannover erforscht werden. Hier wird über erste Forschungsergebnisse aus diesem vom Bundesministerium für Wirtschaft und Energie geförderten Forschungsprojekt berichtet.

Investigations on the fatigue behavior of normal‐strength concrete

The fatigue behavior of concrete is gaining new relevance in context of continuous development in concrete constructions. Modern concretes achieve constantly higher strengths; hence concrete constructions become more and more attractive for new fields of applications like onshore and offshore wind turbines. The fatigue of concrete is of special significance for this type of cyclic loaded constructions. The knowledge of the load cycles to failure is no longer sufficient for the design. There are further questions related to strain and stiffness development and combination of fatigue loading and marine environmental conditions, which are investigated at Leibniz Universität Hannover within the research project “ProBeton”. First results of this research project, which is supported by the Federal Ministry for Economic Affairs and Energy, are presented here.
Fasern unter Feuer
Authors: Heek Peter , Tkocz Jasmin , Thiele Catherina , Vitt Gerhard , Mark Peter
Published: October 2015

Bauteile des üblichen Hochbaus sind in der Regel als feuerwiderstandsfähig auszulegen. Die Bemessung im Brandfall erfolgt für Stahlbetonbauteile nach aktuellen Vorschriften, für stahlfaserverstärkte Stahlbetonbauteile existiert hingegen derzeit kein allgemeingültiges Bemessungskonzept. In der DAfStb‐Richtlinie “Stahlfaserbeton” wird lediglich allgemein auf die Regelungen von DIN EN 1992‐1‐2 in Verbindung mit DIN EN 1992‐1‐2/NA verwiesen. Im Beitrag werden die Ergebnisse von Brandversuchen an sechs Platten mit Betonstahlbewehrung, Stahlfasern oder Kombinationsbewehrung vorgestellt. Basierend auf experimentellen Daten werden der Einfluss variabler Stahlfasergehalte auf den Wärmetransport in Stahlbetonquerschnitten und das temperaturabhängige Trag‐ und Verformungsverhalten bei einseitiger Brandbeanspruchung untersucht. Die Aufbereitung der gewonnenen Erkenntnisse erfolgt im Rahmen eines Bemessungshilfsmittels, welches eine Beurteilung der Restbiegetragfähigkeit von stahlfaserverstärkten Stahlbetonquerschnitten nach 90‐minütiger Brandbeanspruchung (R90) erlaubt. Ein Beispiel zeigt die praktische Anwendung.

Fibres on Fire – Design Charts for Steel Fibre Reinforced Concrete Slabs subjected to elevated temperatures

In general, common structural design has to consider elevated temperatures due to fire. Thereby, cross‐sectional design of reinforced concrete takes place w.r.t. valid standards whereas in presence of steel fibres no standardized approach is available so far. In this case the DAfStb‐Guideline “Stahlfaserbeton” only refers generally to DIN EN 1992‐1‐2 in conjunction with DIN EN 1992‐1‐2/NA. Based on experimental data of reinforced concrete slabs containing variable amounts of steel fibres the influence of fibres on both, the heat transmission of concrete and the temperature dependent load‐deformation behaviour are investigated here. Results of experimental and theoretical analysis are used to provide a design chart allowing for the assessment of load bearing capacities of steel fibre reinforced concrete cross sections subjected to elevated temperatures (R90). An example shows the practical application.
Lipids under stress – a lipidomic approach for the study of mood disorders
Authors: Miranda André Miguel , Oliveira Tiago Gil
Published: October 2015

The emerging field of lipidomics has identified lipids as key players in disease physiology. Their physicochemical diversity allows precise control of cell structure and signaling events through modulation of membrane properties and trafficking of proteins. As such, lipids are important regulators of brain function and have been implicated in neurodegenerative and mood disorders. Importantly, environmental chronic stress has been associated with anxiety and depression and its exposure in rodents has been extensively used as a model to study these diseases. With the accessibility to modern mass‐spectrometry lipidomic platforms, it is now possible to snapshot the extensively interconnected lipid network. Here, we review the fundamentals of lipid biology and outline a framework for the interpretation of lipidomic studies as a new approach to study brain pathophysiology. Thus, lipid profiling provides an exciting avenue for the identification of disease signatures with important implications for diagnosis and treatment of mood disorders.
Colorimetric Cyanide Chemosensor Based on an Amide‐Pyrene Moiety: Experimental and Theoretical Studies
Authors: Lee Yoon Do , Park Gyeong Jin , Choi Ye Won , Kim Cheal
Published: October 2015

A new simple colorimetric sensor 1 based on amide‐pyrene moiety was designed and synthesized for cyanide (CN
‐) in aqueous solution. The sensor 1 showed high selectivity toward CN
−, which induces an immediate color change from colorless to yellow for cyanide over other anions. Moreover, the sensor 1 could be used efficiently in a wide pH range (7–10) with no interference from other anions. The sensing of CN
− was found to be reversible with a proper reagent such as HCl. Additionally, the sensing mechanism for CN
− was theoretically supported by density functional theory and time‐dependent density functional theory calculations. Therefore, sensor 1 can serve as a practical chemosensor for cyanide in aqueous solution.
Argentometric Titration Apparatus with a Light Emitting Diode‐based Nephelometric Detection System
Authors: Bae Hyun‐Soo , Hwang Hoon , Eom In‐Yong
Published: October 2015

A newly revised apparatus for argentometric precipitate titrations was fabricated and evaluated. A light emitting diode was adapted as a solid‐state light source and a syringe pump was used for manipulating titrant both in stopped flow mode and continuous mode. The performance of the two modes was compared in terms of accuracy and precision. The continuous flow mode is much faster and shows generally higher accuracy under given experimental conditions. The patterns of precipitate titration curves were changed with different coagulant concentrations and addition flow rates of titrant. However, end point volumes were not affected by these experimental factors tested here.
Engineering a Constrained Peptidic Scaffold towards Potent and Selective Furin Inhibitors
Authors: Fittler Heiko , Depp Alexander , Avrutina Olga , Dahms Sven O. , Than Manuel E. , Empting Martin , Kolmar Harald
Published: October 2015

We report the engineering of the monocyclic sunflower trypsin inhibitor (SFTI‐1[1,14]) into a potent furin inhibitor. In a rational approach, we converted the native scaffold of this trypsin‐like serine protease inhibitor into a subtilisin‐like one by substitutions in the canonical and, particularly, in the substrate‐binding loop. Although the substrate sequence for furin is Arg‐X‐Arg/Lys‐Arg↓, the most potent inhibitor had a lysine at position P1. C‐terminally truncated versions demonstrated the strongest activity, thus suggesting a lack of interaction between this motif and the surface of furin. This observation was further supported by molecular modeling. With an inhibition constant of 0.49 nm, the engineered peptide H‐KRCKKSIPPICF‐NH2 is a promising compound for further development of furin inhibitors aimed at controlling the activity of this protease in vitro and in vivo.
Transcatheter pulmonary valve replacement: State of the art
Authors: Holzer Ralf J. , Hijazi Ziyad M.
Published: October 2015

Background

The number of patients undergoing transcatheter pulmonary valve replacement has been steadily increasing, resulting in many research projects focusing on this patient population. This has highlighted the need to summarize the currently available data.

Methods

A review of the literature was conducted and the results summarized.

Results

At present, the two commercially available valves approved for transcatheter pulmonary valve replacement include the Edwards Sapien valve and the Medtronic Melody valve. More data has been published relating to the Melody valve; this included the incidence of coronary anatomy prohibiting valve implantation of 5%, an incidence of conduit disruption of 6%, and freedom from stent fracture of the Melody valve stent of 60% at 30 months. Short and medium term outcomes seem to be comparable if not superior to surgical valve replacement, but long‐term data is still lacking. There may also be a cost benefit with transcatheter valve implantation when compared to surgical pulmonary valve replacement.

Conclusions

Transcatheter pulmonary valve replacement is here to stay. The main challenge of treating patients with a native right ventricular outflow tract still needs to be addressed and device development efforts centered in this area. © 2015 Wiley Periodicals, Inc.
Surface Segregation of Fe in Pt–Fe Alloy Nanoparticles: Its Precedence and Effect on the Ordered‐Phase Evolution during Thermal Annealing
Authors: Prabhudev Sagar , Bugnet Matthieu , Zhu Guo‐Zhen , Bock Christina , Botton Gianluigi A.
Published: October 2015

Coupling electron microscopy techniques with in situ heating ability allows us to study phase transformations on the single‐nanoparticle level. We exploit this setup to study disorder‐to‐order transformation of Pt–Fe alloy nanoparticles, a material that is of great interest to fuel‐cell electrocatalysis and ultrahigh density information storage. In contrast to earlier reports, we show that Fe (instead of Pt) segregates towards the particle surface during annealing and forms a Fe‐rich FeOx outer shell over the alloy core. By combining both ex situ and in situ approaches to probe the interplay between ordering and surface‐segregation phenomena, we illustrate that the surface segregation of Fe precedes the ordering process and affects the ordered phase evolution dramatically. We show that the ordering initiates preferably at the pre‐existent Fe‐rich shell than the particle core. While the material‐specific findings from this study open interesting perspectives towards a controlled phase evolution of Pt–Fe nanoalloys, the characterization methodologies described are general and should prove useful to probing a wide‐range of nanomaterials.
Combined Adsorption/Ultrafiltration of Secondary Effluents Using Powdered Zeolites
Authors: Chen Yong , Tu Yong , Bai Yonggang , Tang Min , Liu Weijing , Wu Haisuo
Published: October 2015

The performance of powdered zeolite (PZ) adsorption/ultrafiltration (UF) with real secondary effluents is investigated. With the assistance of PZs, the membrane fouling rate was reduced and the permeate flux recovery as well as the advanced treatment of the secondary effluents were enhanced. 3D excitation emission matrix (3D‐EEM) fluorescence spectra indicate that the removal of fluorescence intensity for aromatic proteins, fulvic acid‐like materials, soluble microbial by‐product‐like materials, and humic acid‐like organics could be improved by PZs. UF membranes with PZs can increase the removal efficiency of organics, especially of those with low molecular weight. The characteristics of the cake layer on the surface of an UF membrane were determined by scanning electron microscopy and electron energy‐dispersive X‐ray spectroscopy for the combined adsorption/UF membrane.
Reactivity of the Donor‐Stabilized Silylenes [iPrNC(Ph)NiPr]2Si and [iPrNC(NiPr2)NiPr]2Si: Activation of CO2 and CS2
Authors: Mück Felix M. , Baus Johannes A. , Nutz Marco , Burschka Christian , Poater Jordi , Bickelhaupt F. Matthias , Tacke Reinhold
Published: October 2015

Activation of CO2 by the bis(amidinato)silylene 1 and the analogous bis(guanidinato)silylene 2 leads to the structurally analogous six‐coordinate silicon(IV) complexes 4 (previous work) and 8, respectively, the first silicon compounds with a chelating carbonato ligand. Likewise, CS2 activation by silylene 1 affords the analogous six‐coordinate silicon(IV) complex 10, the first silicon compound with a chelating trithiocarbonato ligand. CS2 activation by silylene 2, however, yields the five‐coordinate silicon(IV) complex 13 with a carbon‐bound CS22− ligand, which also represents an unprecedented coordination mode in silicon coordination chemistry. Treatment of the dinuclear silicon(IV) complexes 5 and 6 with CO2 also affords the six‐coordinate carbonatosilicon(IV) complexes 4 and 8, respectively.
ChemInform Abstract: Nanocomposites of Graphene/Polymers: A Review
Authors: Chee W. K. , Lim H. N. , Huang N. M. , Harrison I.
Published: October 2015

Review: fabrication, properties and practical applications; 176 refs.
Gadusol, ein hochwirksamer biogener UV‐Schutz
Authors: Hille‐Rehfeld Annette
Published: October 2015

Die enorme Photostabilität und bestechend einfache Struktur von Gadusol begründet sein über die biologische Funktion hinausgehendes Potential. Nachdem der Biosyntheseweg lange Zeit rätselhaft blieb, eröffnet die Entdeckung eines von Mikroorganismen bis hin zu den Wirbeltieren konservierten Genclusters neue Perspektiven für die biotechnologische Produktion.
Förderung der Grundlagenforschung
Authors: Behnke Markus
Published: October 2015

Als die Selbstverwaltungsorganisation der Wissenschaft in Deutschland ist die Deutsche Forschungsgemeinschaft (DFG) ein verlässlicher Partner für die erkenntnisorientierte Grundlagenforschung. Ihre Kernaufgabe besteht in der wettbewerblichen Auswahl der besten Forschungsvorhaben von Wissenschaftlerinnen und Wissenschaftlern an Hochschulen und Forschungsinstituten und in deren Finanzierung. Dabei gilt besondere Aufmerksamkeit dem wissenschaftlichen Nachwuchs und der Chancengleichheit im Wissenschaftssystem. Ein Anliegen der DFG ist die interdisziplinäre und internationale Zusammenarbeit in der Wissenschaft, sowie der Austausch mit Wirtschaft und Gesellschaft. Darüber hinaus berät die DFG Parlamente, Regierungen und öffentliche Institutionen in wissenschaftlichen Fragen und informiert die Öffentlichkeit. Die DFG steht für Verantwortung in der Wissenschaft [1].
A computer‐aided framework for product design with application to wheat straw polypropylene composites
Authors: Fatoni Rois , Elkamel Ali , Simon Leonardo , Almansoori Ali
Published: October 2015

The use of wheat straw and other agricultural byproduct fibres in polymer composite materials offers many economic and environmental benefits. Wheat straw has been recently commercialized as a new filler for polypropylene thermoplastic composites in automotive applications. However, to expand its application in the automotive industry and other sectors where highly‐engineered materials are needed, a systematic database and reliable composite property models are needed. For this purpose, this research aims to develop a product design approach based on mixture design methodologies and inverse optimization for wheat straw polypropylene (WS‐PP) composites for the automotive industry. The approach follows hierarchical steps starting from consumer needs and ending with specific end‐products. Relevant information obtained systematically from historical data is used to design experiments and develop response surface models of composite properties as a function of a composite's component proportion. The response surface models are used to simulate and optimize the composition formulation of the composite, which meets the targeted product specifications. The last step of the proposed methodology is to optimize the composite ingredients to maximize wheat straw utilization in the final composite while minimizing the overall material cost. A case study is presented for the design of wheat straw polypropylene/impact copolymer polypropylene (WS‐PP/ICP) composite for the automotive industry.
Degeneration of proprioceptive sensory nerve endings in mice harboring amyotrophic lateral sclerosis–causing mutations
Authors: Vaughan Sydney K. , Kemp Zachary , Hatzipetros Theo , Vieira Fernando , Valdez Gregorio
Published: October 2015

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that primarily targets the motor system. Although much is known about the effects of ALS on motor neurons and glial cells, little is known about its effect on proprioceptive sensory neurons. This study examines proprioceptive sensory neurons in mice harboring mutations associated with ALS, in SOD1G93A and TDP43A315T transgenic mice. In both transgenic lines, we found fewer proprioceptive sensory neurons containing fluorescently tagged cholera toxin in their soma five days after injecting this retrograde tracer into the tibialis anterior muscle. We asked whether this is due to neuronal loss or selective degeneration of peripheral nerve endings. We found no difference in the total number and size of proprioceptive sensory neuron soma between symptomatic SOD1G93A and control mice. However, analysis of proprioceptive nerve endings in muscles revealed early and significant alterations at Ia/II proprioceptive nerve endings in muscle spindles before the symptomatic phase of the disease. Although these changes occur alongside those at α‐motor axons in SOD1G93A mice, Ia/II sensory nerve endings degenerate in the absence of obvious alterations in α‐motor axons in TDP43A315T transgenic mice. We next asked whether proprioceptive nerve endings are similarly affected in the spinal cord and found that nerve endings terminating on α‐motor neurons are affected during the symptomatic phase and after peripheral nerve endings begin to degenerate. Overall, we show that Ia/II proprioceptive sensory neurons are affected by ALS‐causing mutations, with pathological changes starting at their peripheral nerve endings. J. Comp. Neurol. 523:2477–2494, 2015. © 2015 Wiley Periodicals, Inc.
Gold Nanoparticles in DNA‐Based Multilayer Films: Synthesis, Size Control, and Influence of the Multilayer Structure on Catalytic Properties
Authors: Zinchenko Anatoly , Nagahama Chihiro , Murata Shizuaki
Published: October 2015

A method to prepare DNA‐based multilayered microcapsules as a host matrix for synthesizing ultrasmall gold nanoparticles of 2–4 nm in size is presented. Utilizing the intrinsic affinity of DNA for transition metal ions, ionic gold was first efficiently concentrated inside the DNA‐based multilayers assembled on a CaCO3 sacrificial template. Further reduction of ionic gold inside the multilayers resulted in the formation of high‐density, well‐dispersed 2–4 nm gold nanoparticles distributed evenly and exclusively inside the polyelectrolyte multilayers. Metallized multilayers containing ultrafine gold nanoparticles showed a good performance in catalytic reduction of nitroaromatic compounds and the catalytic activity of gold nanoparticles was enhanced with a decrease of host multilayer thickness. The influence of the multilayer structure and composition on size and catalytic activity of gold nanoparticles is discussed.
The Role of Religious Coping and Resilience in Individuals With Dissociative Identity Disorder
Authors: Bell Hope , Jacobson Lamerial , Zeligman Melissa , Fox Jesse , Hundley Gulnora
Published: October 2015

Survivors with dissociative identity disorder (DID) often report a history of traumatic events in their lives. Past studies indicated a link between trauma, resilience, and spiritual coping in both positive and negative aspects of a survivor's life. This article includes a review of existing literature salient to these constructs in relation to individuals with DID, as well as results from a study examining the relationships between these constructs and individuals with DID (N = 52). Implications are discussed based on the findings for counselors treating individuals with DID.
Closeness and Control: Exploring the Relationship Between Prayer and Mental Health
Authors: Jeppsen Benjamin , Pössel Patrick , Black Stephanie Winkeljohn , Bjerg Annie , Wooldridge Don
Published: October 2015

This study explored closeness to God and God‐mediated control as mediators in the relationship between prayer and mental health. The authors tested 3 models for mediation using structural equation modeling to assess the separate and combined effects in an online sample of 330 praying adults from predominantly Christian backgrounds. Although both mediators were relevant when entered separately, closeness to God proved to be a superior mediator when both variables were entered in 1 model. Counselors should consider prayer behaviors when culturally relevant and encourage meditative and colloquial prayer for clients where increased sources of perceived social support would be beneficial.
A Cross‐Cultural Exploration of Perceptions of Altruism of Counselors‐in‐Training
Authors: Limberg Dodie , Ohrt Jonathan H. , Barden Sejal M. , Ha Yo‐Sang , Hundley Gulnora , Wood Andrew W.
Published: October 2015

This study explored altruistic development as perceived by counselors‐in‐training from diverse cultures. Twenty‐two counselors‐in‐training from 4 countries participated in semistructured interviews about altruism. Using consensual qualitative research methodology, the authors identified 6 domains: biological, cognitive, social learning, religious/spiritual, counseling, and empathy. Findings and implications for counselor education are discussed.
Applied Participatory Ethics: Bridging the Social Justice Chasm Between Counselor and Client
Authors: Tarvydas Vilia , Vazquez‐Ramos Robinson , Estrada‐Hernandez Noel
Published: October 2015

The authors introduce an applied participatory ethics paradigm consistent with the contemporary focus on social justice in the practice of counseling, emphasizing participation of all rightful parties, including the client, in ethical decision‐making processes. The paradigm is an adaptation and expansion of the work of Prilleltensky, Rossiter, and Walsh‐Bowers () and rests on their conceptualization of restrictive and participatory orientations. The origins of the model's added elements in 4 areas of rehabilitation and counseling literature (i.e., ethical knowledge and practices, the therapeutic alliance or relationship, client involvement, and client empowerment) are described. Finally, interrelationships between the different phases and elements of the model are discussed.