bluuebunny/crossref_metadata_2025 huggingface dataset:
A new source of the midlatitude ionospheric peak density structure revealed by a new Ionosphere‐Plasmasphere model
Authors: Maruyama Naomi , Sun Yang‐Yi , Richards Phillip G. , Middlecoff Jacques , Fang Tzu‐Wei , Fuller‐Rowell Timothy J. , Akmaev Rashid A. , Liu Jaun‐Yeng , Valladares Cesar E.
Published: February 2016

The newly developed Ionosphere‐Plasmasphere (IP) model has revealed neutral winds as a primary source of the “third‐peak” density structure in the daytime global ionosphere that has been observed by the low‐latitude ionospheric sensor network GPS total electron content measurements over South America. This third peak is located near −30° magnetic latitude and is clearly separate from the conventional twin equatorial ionization anomaly peaks. The IP model reproduces the global electron density structure as observed by the FORMOSAT‐3/COSMIC mission. The model reveals that the third peak is mainly created by the prevailing neutral meridional wind, which flows from the summer hemisphere to the winter hemisphere lifting the plasma along magnetic field lines to higher altitudes where recombination is slower. The same prevailing wind that increases the midlatitude density decreases the low‐latitude density in the summer hemisphere by counteracting the equatorial fountain flow. The longitudinal variation of the three‐peak structure is explained by the displacement between the geographic and geomagnetic equators.
Drivers of spring and summer variability in the coastal ocean offshore of Cape Cod, MA
Authors: Kirincich Anthony R. , Gawarkiewicz Glen G.
Published: February 2016

The drivers of spring and summer variability within the coastal ocean east of Cape Cod, Massachusetts, a critical link between the Gulf of Maine and Mid‐Atlantic Bight, are investigated using 2 years of shipboard and moored hydrographic and velocity observations from 2010 and 2011. The observations reveal sharp differences in the spring transition and along‐shelf circulation due to variable freshwater and meteorological forcing, along with along‐shelf pressure gradients. The role of the along‐shelf pressure gradient is inferred using in situ observations of turbulent momentum flux, or Reynolds stresses, estimated from the ADCP‐based velocities using recently developed methods and an inversion of the along‐shelf momentum balance. During spring, the locally relevant along‐shelf pressure gradient contains a sizable component that is not coupled to the along‐shelf winds and often opposes the regional sea level gradient. Together with the winds, local pressure gradients dominate along‐shelf transport variability during spring, while density‐driven geostrophic flows appear to match the contribution of the local winds during summer. These results suggest that local effects along the Outer Cape have the potential to cause significant changes in exchange between the basins.
Understanding and quantifying focused, indirect groundwater recharge from ephemeral streams using water table fluctuations
Authors: Cuthbert M. O. , Acworth R. I. , Andersen M. S. , Larsen J. R. , McCallum A. M. , Rau G. C. , Tellam J. H.
Published: February 2016

Understanding and managing groundwater resources in drylands is a challenging task, but one that is globally important. The dominant process for dryland groundwater recharge is thought to be as focused, indirect recharge from ephemeral stream losses. However, there is a global paucity of data for understanding and quantifying this process and transferable techniques for quantifying groundwater recharge in such contexts are lacking. Here we develop a generalized conceptual model for understanding water table and groundwater head fluctuations due to recharge from episodic events within ephemeral streams. By accounting for the recession characteristics of a groundwater hydrograph, we present a simple but powerful new water table fluctuation approach to quantify focused, indirect recharge over both long term and event time scales. The technique is demonstrated using a new, and globally unparalleled, set of groundwater observations from an ephemeral stream catchment located in NSW, Australia. We find that, following episodic streamflow events down a predominantly dry channel system, groundwater head fluctuations are controlled by pressure redistribution operating at three time scales from vertical flow (days to weeks), transverse flow perpendicular to the stream (weeks to months), and longitudinal flow parallel to the stream (years to decades). In relative terms, indirect recharge decreases almost linearly away from the mountain front, both in discrete monitored events as well as in the long‐term average. In absolute terms, the estimated indirect recharge varies from 80 to 30 mm/a with the main uncertainty in these values stemming from uncertainty in the catchment‐scale hydraulic properties.
Biased self‐perceived social competence and engagement in subtypes of aggression: Examination of peer rejection, social dominance goals, and sex of the child as moderators
Authors: McQuade Julia D. , Breaux Rosanna P. , Gómez Angelina F. , Zakarian Rebecca J. , Weatherly Julia
Published: February 2016

This study expands on prior research suggesting that children who either over‐ or under‐estimate their social competence relative to others’ reports are more likely to be aggressive. Linear and curvilinear associations between biased social self‐perceptions and forms (physical vs. relational) and functions (proactive vs. reactive) of aggression were tested along with three moderators (peer rejection, social dominance goals, and child sex). Children in the fifth through eight grade (N = 167) completed self‐reports of perceived social competence and social dominance goals. Teachers completed ratings of children's social competence, peer rejection, and reactive and proactive physical and relational aggression. Bias in self‐perceived social competence was quantified as the residual difference between child and teacher ratings of the child's social competence. There was a significant interaction between quadratic bias and peer rejection predicting reactive physical aggression; rejected children with a positive bias or a negative bias were highest in reactive physical aggression. The interaction between linear bias, social dominance goals, and the sex of the child was also significant when predicting proactive physical aggression. Among girls who highly valued social dominance, a positive bias predicted greater proactive physical aggression. Results are discussed in terms of implications for aggression theory and intervention. Aggr. Behav. 42:498–509, 2016. © 2016 Wiley Periodicals, Inc.
Modeling Individual Differences in Autobiographical Memory Distributions Using Mixed Logitnormal Regression
Authors: Zimprich Daniel , Wolf Tabea
Published: February 2016

We introduce a model for examining individual differences in the lifespan distribution of autobiographical memories (after the exclusion of recent memories). The model is based on the logitnormal distribution, contains two submodels, one for location (average age at which autobiographical memories were encoded) and one for scale (range of ages at which autobiographical memories were encoded), allows for the inclusion of predictor variables, and includes random effects. The model was used to analyze autobiographical memories reported by 90 older participants. Results show that there were reliable individual differences in location and scale. Moreover, age, proportion of positive memories, proportion of first‐time experiences, comprehensibility, and meaningfulness accounted for 26% of individual differences in location and 23% of individual differences in scale of autobiographical memory distributions. These findings indicate that individual differences are present in autobiographical memory distributions and can, in part, be accounted for by characteristics of the memories and of the person who generated them.Copyright © 2016 John Wiley & Sons, Ltd.
Theoretical Study of Cellular Piezoelectret Generators
Authors: Li Wenbo , Wu Nan , Zhong Junwen , Zhong Qize , Zhao Sheng , Wang Bo , Cheng Xiaofeng , Li Suling , Liu Kang , Hu Bin , Zhou Jun
Published: February 2016

The cellular piezoelectret generator (CPG) has drawn considerable attention as an emerging flexible energy harvester because of its advantages of a simple structure, easy assembly, a low cost, and eco‐friendliness. To facilitate practical applications, an initial theoretical study of CPGs is presented in this work, in which the output characteristics of CPGs can be optimized through an appropriate choice of parameters, including the electret dielectric permittivity, device structure, polarization process, and external load. A good agreement with experimental results is achieved, verifying the validity of the theoretical study. The reported theory offers a complete interpretation of the dynamic working mechanism of CPGs and provides significant guidance for the design of a CPG with enhanced yield.
Hyaluronic Acid‐Based Hydrogels Enable Rod Photoreceptor Survival and Maturation In Vitro through Activation of the mTOR Pathway
Authors: Mitrousis Nikolaos , Tam Roger Y. , Baker Alexander E. G. , van der Kooy Derek , Shoichet Molly S.
Published: February 2016

The culture of isolated photoreceptors in vitro has remained elusive in ­neuroscience. By using defined hyaluronic acid (HA) hydrogels, photo­receptor survival and maturation in vitro is dramatically increased, as evidenced by upregulation of outer segment markers at the RNA and protein levels. While substrate stiffness is known to be a key factor influencing cell survival in vitro, it is shown that isolated photoreceptors do not respond to modifications in hydrogel stiffness modifications but depend, instead, on HA for survival. While the molecular pathways that are induced by HA on photoreceptors are unknown, mTOR activation is identified as the molecular mechanism underlying the pro‐survival effect, and it is demonstrated that the canonical Wnt and RhoA pathways are intermediaries. This work establishes a valuable method for isolated photoreceptor culture in vitro, which will be useful in translational and basic retinal research. The pathways identified herein may be useful targets in retinal degeneration.
Ultrafast Spectroscopy of Photoexcitations in Organometal Trihalide Perovskites
Authors: Zhai Yaxin , Sheng Chuan Xiang , Zhang Chuang , Vardeny Zeev Valy
Published: February 2016

Studying the room temperature broadband ultrafast transient response of photoexcitations in three perovskite films, namely MAPbI3, MAPbI1.1Br1.9, and MAPbI3−xClx (MA = CH3NH3), allowed unravelling the branching ratio between photogenerated carriers and excitons, a key factor for optoelectronic applications of perovskites. An instantaneously generated mid‐IR photoinduced absorption (PA) band, PA1 is observed in all three perovskites, as well as a strong derivative‐like band of photoinduced bleaching (PB) and PA (PA2) close to the corresponding absorption band edge. From the distinguished different decay dynamics of the PA bands in MAPbI3, PA1 is interpreted as due to the exciton transition, whereas PA2 and PB are due to band‐filling effect caused by the photocarriers. In contrast, all bands in MAPbI1.1Br1.9 and MAPbI3−xClx share the same dynamics and are therefore due to the same species, namely photogenerated excitons. The transient photoinduced polarization memory (POM) for both excitons and photocarriers as well as the steady‐state photoluminescence (PL) emission are observed in MAPbI3, but not in MAPbI1.1Br1.9 and MAPbI3−xClx because they possess cubic symmetry at room temperature. The estimated long excitons diffusion length (≈150 nm) in MAPbI3 opens up the possibility of photocarriers generation at interfaces and grain boundaries even when the exciton binding energy is large compare to kBT.
Flexible and Stretchable Physical Sensor Integrated Platforms for Wearable Human‐Activity Monitoringand Personal Healthcare
Authors: Trung Tran Quang , Lee Nae‐Eung
Published: February 2016

Flexible and stretchable physical sensors that can measure and quantify electrical signals generated by human activities are attracting a great deal of attention as they have unique characteristics, such as ultrathinness, low modulus, light weight, high flexibility, and stretchability. These flexible and stretchable physical sensors conformally attached on the surface of organs or skin can provide a new opportunity for human‐activity monitoring and personal healthcare. Consequently, in recent years there has been considerable research effort devoted to the development of flexible and stretchable physical sensors to fulfill the requirements of future technology, and much progress has been achieved. Here, the most recent developments of flexible and stretchable physical sensors are described, including temperature, pressure, and strain sensors, and flexible and stretchable sensor‐integrated platforms. The latest successful examples of flexible and stretchable physical sensors for the detection of temperature, pressure, and strain, as well as their novel structures, technological innovations, and challenges, are reviewed first. In the next section, recent progress regarding sensor‐integrated wearable platforms is overviewed in detail. Some of the latest achievements regarding self‐powered sensor‐integrated wearable platform technologies are also reviewed. Further research direction and challenges are also proposed to develop a fully sensor‐integrated wearable platform for monitoring human activity and personal healthcare in the near future.
Device Engineered Organic Transistors for Flexible Sensing Applications
Authors: Zang Yaping , Huang Dazhen , Di Chong‐an , Zhu Daoben
Published: February 2016

Organic thin‐film transistors (OFETs) represent a promising candidate for next‐generation sensing applications because of the intrinsic advantages of organic semiconductors. The development of flexible sensing devices has received particular interest in the past few years. The recent efforts of developing OFETs for sensitive and specific flexible sensors are summarized from the standpoint of device engineering. The tuning of signal transduction and signal amplification are highlighted based on an overview of active‐layer thickness modulation, functional receptor implantation and device geometry optimization.
A Series of Pyrene‐Substituted Silicon Phthalocyanines as Near‐IR Sensitizers in Organic Ternary Solar Cells
Authors: Ke Lili , Min Jie , Adam Matthias , Gasparini Nicola , Hou Yi , Perea J. Darío , Chen Wei , Zhang Hong , Fladischer Stefanie , Sale Anna‐Chiara , Spiecker Erdmann , Tykwinski Rik R. , Brabec Christoph J. , Ameri Tayebeh
Published: February 2016

An attractive method to broaden the absorption bandwidth of polymer/fullerene‐based bulk heterojunction (BHJ) solar cells is to blend near infrared (near‐IR) sensitizers into the host system. Axial substitution of silicon phthalocyanines (Pcs) opens a possibility to modify the chemical, thermodynamic, electronic, and optical properties. Different axial substitutions are already designed to modify the thermodynamic properties of Pcs, but the impact of extending the π‐conjugation of the axial ligand on the opto‐electronic properties, as a function of the length of the alkyl spacer, has not been investigated yet. For this purpose, a novel series of pyrene‐substituted silicon phthalocyanines (SiPc‐Pys) with varying lengths of alkyl chain tethers are synthesized. The UV–vis and external quantum efficiency (EQE) results exhibit an efficient near IR sensitization up to 800 nm, clearly establishing the impact of the pyrene substitution. This yields an increase of over 20% in the short circuit current density (J
SC) and over 50% in the power conversion efficiency (PCE) for the dye‐sensitized ternary device. Charge generation, transport properties, and microstructure are studied using different advanced technologies. Remarkably, these results provide guidance for the diverse and judicious selection of dye sensitizers to overcome the absorption limitation and achieve high efficiency ternary solar cells.
Stereoselektive Halogenierungen in der Naturstoffsynthese
Authors: Chung Won‐jin , Vanderwal Christopher D.
Published: February 2016

Nach letzter Zählung sind nahezu 5000 halogenierte Naturstoffe entdeckt worden. In etwa der Hälfte dieser Verbindungen ist das Kohlenstoffatom, an welches das Halogen gebunden ist, sp3‐hybridisiert; es gibt also eine enorme Zahl von Naturstoffen, für welche die stereokontrollierte Halogenierung ein entscheidender Bestandteil der Synthesestrategie sein muss. In diesem Aufsatz diskutieren wir Methoden und Strategien, die zur stereoselektiven Einführung von Halogenatomen im Zusammenhang mit Naturstoffsynthesen genutzt wurden. Außerdem identifizieren wir verbliebene Lücken in der Synthesetechnologie sowie existierende Methoden, die noch nicht in der Synthese komplexer Moleküle verwendet wurden. Die hier beschriebene Chemie demonstriert erneut, wie Naturstoffe als Inspirationsquelle für wichtige Fortschritte in der chemischen Synthese dienen.
Insights into 6‐Methylsalicylic Acid Bio‐assembly by Using Chemical Probes
Authors: Parascandolo James S. , Havemann Judith , Potter Helen K. , Huang Fanglu , Riva Elena , Connolly Jack , Wilkening Ina , Song Lijiang , Leadlay Peter F. , Tosin Manuela
Published: February 2016

Chemical probes capable of reacting with KS (ketosynthase)‐bound biosynthetic intermediates were utilized for the investigation of the model type I iterative polyketide synthase 6‐methylsalicylic acid synthase (6‐MSAS) in vivo and in vitro. From the fermentation of fungal and bacterial 6‐MSAS hosts in the presence of chain termination probes, a full range of biosynthetic intermediates was isolated and characterized for the first time. Meanwhile, in vitro studies of recombinant 6‐MSA synthases with both nonhydrolyzable and hydrolyzable substrate mimics have provided additional insights into substrate recognition, providing the basis for further exploration of the enzyme catalytic activities.
Synthesis of Nitrogen‐Containing Rubicene and Tetrabenzopentacene Derivatives
Authors: Park Young S. , Dibble David J. , Kim Juhwan , Lopez Robert C. , Vargas Eriberto , Gorodetsky Alon A.
Published: February 2016

Carbon‐based materials, such as acenes, fullerenes, and graphene nanoribbons, are viewed as the potential successors to silicon in the next generation of electronics. Although a number of methodologies provide access to these materials’ all‐carbon variants, relatively fewer strategies readily furnish their nitrogen‐doped analogues. Herein, we report the rational design, preparation, and characterization of nitrogen‐containing rubicenes and tetrabenzopentacenes, which can be viewed either as acene derivatives or as molecular fragments of fullerenes and graphene nanoribbons. The reported findings may prove valuable for the development of electron transporting organic semiconductors and for the eventual construction of larger carbonaceous systems.
Rotating Magnetocaloric Effect in an Anisotropic Molecular Dimer
Authors: Lorusso Giulia , Roubeau Olivier , Evangelisti Marco
Published: February 2016

In contrast to the mainstream research on molecular refrigerants that seeks magnetically isotropic molecules, we show that the magnetic anisotropy of dysprosium acetate tetrahydrate, [{Dy(OAc)3(H2O)2}2]⋅4 H2O (1), can be efficiently used for cooling below liquid‐helium temperature. This is attained by rotating aligned single‐crystal samples in a constant applied magnetic field. The envisioned advantages are fast cooling cycles and potentially compact refrigerators.
Faltung einer RNA‐Haarnadel in der dicht gedrängten Zelle
Authors: Gao Mimi , Gnutt David , Orban Axel , Appel Bettina , Righetti Francesco , Winter Roland , Narberhaus Franz , Müller Sabine , Ebbinghaus Simon
Published: February 2016

Eine korrekte und präzise Faltung der Sekundär‐ und Tertiärstruktur ist von entscheidender Bedeutung für die zelluläre Funktionalität von Ribonukleinsäuren (RNA). Faltungsstudien von RNA wurden allerdings überwiegend in vitro durchgeführt, ohne die Möglichkeit solche Experimente in vivo zu validieren. In dieser Arbeit konnten wir die Faltungsstabilität einer RNA‐Haarnadel direkt in lebenden Säugerzellen auflösen. Die Ergebnisse zeigen, dass die Faltungsstabilität innerhalb der Zelle mit der in einer verdünnten physiologischen Pufferlösung vergleichbar ist. Die In‐vitro‐Verwendung von künstlichen Crowding‐Reagentien, mit der Ausnahme vom hochmolekularen PEG, führt hingegen zu einer Destabilisierung der Haarnadel, die aus Oberflächenwechselwirkung und Verminderung der Wasseraktivität resultiert. Ferner ist die Faltungsstabilität der RNA äußerst variabel, sowohl innerhalb einer Zellpopulation als auch auf der subzellulären Ebene des Zellkerns und des Zytoplasmas. Demzufolge unterliegt die RNA im Inneren der Zelle (lokalisierten) stabilisierenden und destabilisierenden Effekten, die im Mittel und im Vergleich zu der verdünnten Pufferlösung nur eine geringfügige Modulation der Faltungsstabilität verursachen.
Dithienophosphole‐Based Phosphinamides with Intriguing Self‐Assembly Behavior
Authors: Wang Zisu , Gelfand Benjamin S. , Baumgartner Thomas
Published: February 2016

A new, highly adaptable type of phosphinamide‐based hydrogen bonding is representatively demonstrated in π‐conjugated phosphole materials. The rotational flexibility of these intermolecular P=O−H−N hydrogen bonds is demonstrated by X‐ray crystallography and variable‐concentration NMR spectroscopy. In addition to crystalline compounds, phosphinamide hydrogen bonding was successfully introduced into the self‐assembly of soft crystals, liquid crystals, and organogels, thus highlighting the high general value of this type of interaction for the formation of organic soft materials.
Epicochalasines A and B: Two Bioactive Merocytochalasans Bearing Caged Epicoccine Dimer Units from Aspergillus flavipes
Authors: Zhu Hucheng , Chen Chunmei , Tong Qingyi , Li Xiao‐Nian , Yang Jing , Xue Yongbo , Luo Zengwei , Wang Jianping , Yao Guangmin , Zhang Yonghui
Published: February 2016

Two bioactive merocytochalasans, epicochalasines A (1) and B (2), a new class of cytochalasans bearing unexpected scaffolds consisting of fused aspochalasin and epicoccine dimer moieties, were isolated from the liquid culture broth of Aspergillus flavipes. Both 1 and 2 possess a hendecacyclic 5/6/11/5/6/5/6/5/6/6/5 ring system containing an adamantyl cage and as many as 19 stereogenic centers; however, the fusion patterns of 1 and 2 differ greatly, thus resulting in different carbon skeletons. The absolute configurations of 1 and 2 were determined by X‐ray diffraction and calculated ECD, respectively. The biogenetic pathways of 1 and 2 are proposed to involve Diels–Alder and nucleophilic addition reactions. Both 1 and 2 induced significant G2/M‐phase cell‐cycle arrest. Furthermore, we found that merocytochalasans induce apoptosis in leukemia cells through the activation of caspase‐3 and the degradation of PARP.
Nickel‐Catalyzed Decarboxylative Difluoroalkylation of α,β‐Unsaturated Carboxylic Acids
Authors: Li Gang , Wang Tao , Fei Fan , Su Yi‐Ming , Li Yan , Lan Quan , Wang Xi‐Sheng
Published: February 2016

The first example of nickel‐catalyzed decarboxylative fluoroalkylation of α,β‐unsaturated carboxylic acids has been developed with commonly available fluoroalkyl halides. This novel transformation has demonstrated broad substrate scope, excellent functional‐group tolerance, mild reaction conditions, and excellent stereoselectivity. Mechanistic investigations indicate that a fluoroalkyl radical is involved in the catalytic cycle.
A P−H Functionalized Al/P Frustrated Lewis Pair: Substrate Activation and Selective Hydrogen Transfer
Authors: Keweloh Lukas , Klöcker Hans , Würthwein Ernst‐Ulrich , Uhl Werner
Published: February 2016

Hydroalumination of an alkynylphosphine gave an unprecedented P−H functionalized frustrated Lewis pair (FLP). The reactive P−H group does not influence the typical FLP properties, but the activation of substrates follows a new reaction pattern involving hydrogen transfer to yield unusual compounds with phosphaurea, iminophosphine, or phosphanyltriazene structural motifs.
Cellular Synthesis of Protein Catenanes
Authors: Wang Xiao‐Wei , Zhang Wen‐Bin
Published: February 2016

Direct cellular production of topologically complex proteins is of great interest both in supramolecular chemistry and protein engineering. We describe the first cellular synthesis of protein catenanes through the use of the p53 dimerization domain to guide the intertwining of two protein chains and SpyTag–SpyCatcher chemistry for efficient cyclization. The catenane topology was unambiguously proven by SDS‐PAGE, SEC, and partial digestion experiments and was shown to confer enhanced stability toward trypsin digestion relative to monomeric control mutants. The assembly–reaction synergy enabled by protein folding and genetically encoded protein chemistry offers a convenient yet powerful approach for creating mechanically interlocked, complex protein topologies in vivo.
Using feedback from summer subtropical highs to evaluate climate models
Authors: Sánchez de Cos Carmen , Sánchez‐Laulhé Jose M. , Jiménez‐Alonso Carlos , Rodríguez‐Camino Ernesto
Published: February 2016

This letter aims to broaden the spectrum of methods for model evaluation by providing new physically based metrics that focus on accurate couplings between subsystems of the climate system. A simplified version of the feedback scheme that describes the dynamics of subtropical high‐pressure systems is applied to evaluate how well CMIP5 climate models can simulate atmosphere–ocean–land interactions and resulting feedbacks in the Azores high‐pressure system during summer, which affects climate throughout the Atlantic near southern Europe and North Africa.
Dämpfungsverhalten unterschiedlicher Fluide in einem Flüssigkeitstilgersystem
Authors: Schellander Janez , Strauss Alfred
Published: February 2016

Die Verwendung von Flüssigkeitstilgersystemen (Tuned liquid column dampers – TLCD) zur Dämpfung unerwünschter Strukturschwingungen stellt eine gute Alternative zu herkömmlichen Dämpfungssystemen dar. Diese werden in der Regel durch sogenannte Isolatoren oder Dissipatoren bzw. mithilfe von Masse‐Feder‐Dämpfern (TMD) reduziert. Isolatoren und Dissipatoren arbeiten ohne zusätzliche Masse, TMD‐Systeme besitzen eine zusätzliche Masse, welche über eine Feder und meist einen viskosen Dämpfer mit dem Hauptsystem gekoppelt ist. Eben diese zusätzliche Masse sorgt sowohl beim TMD als auch beim Flüssigkeitstilger durch ihre dem Hauptsystem gegenläufige Bewegung für den gewünschten Dämpfungseffekt. Die theoretischen wie auch praktischen Laboruntersuchungen der Bemessungsparameter des Flüssigkeitstilgers sind Gegenstand des vorliegenden Beitrags. Besonderes Augenmerk liegt hierbei auf der Eigendämpfung des Fluids. Diese hängt wesentlich von den rheologischen Eigenschaften der Flüssigkeit selbst ab und weist dementsprechend – je nach Flüssigkeit – relativ große Unterschiede auf. Dieser Beitrag beschreibt zum einen theoretische, rheologische Grundlagen und zum anderen untersucht und überprüft er deren Auswirkungen auf das Dämpfungsverhalten eines Flüssigkeitstilgers anhand von Versuchsergebnissen. Ziel war es, die Auswirkungen der Flüssigkeitseigenschaften wie Viskosität, Scherraten, Dichte usw. auf die Eigendämpfung der Flüssigkeit darzustellen und zu vergleichen. Darüber hinaus sollte der Zusammenhang von Tilgerdämpfung und der Dämpfung des Gesamtsystems dargestellt werden. Dafür wurden mittels eines eigens entwickelten Versuchsstands Ausschwingversuche durchgeführt und die ausgewerteten Zeitverläufe gegenübergestellt.

Damping behavior of different fluids used for a Tuned Liquid Column Damper System

Tuned liquid column dampers (TLCD) represent a good alternative to other commonly used damping systems applied on engineering structures. The use of an additional mass causes a contrary motion in relation to the main oscillating system. This contrary motion enables an efficient way to mitigate unwanted structural vibrations. To obtain high damping efficiencies certain parameters of the TLCD must be optimized and adjusted to the main system. Important parameters would be the mass – m, the eigenfrequency of the damper fT, the stiffness and of course the damping of the system itself. The theoretical and experimental investigations of certain parameters are the aim of this contribution. The main focus was on the damping term of the TLCD. Since it is strongly dependent on the rheological parameters of the fluid, such as viscosity, shear rates, density etc. different fluids were tested and after evaluation compared. To execute these experiments, a test stand has been designed and built. So the main aim of this research work is to theoretically explain fundamental fluid parameters and in a further step to show how a change of these parameters changes the damping behavior of the TLCD.
Belastungsversuche – Internationaler Stand des Wissens
Authors: Schacht Gregor , Bolle Guido , Marx Steffen
Published: February 2016

Belastungsversuche sind in Deutschland seit 15 Jahren durch die Richtlinie des Deutschen Ausschusses für Stahlbeton (DAfStb) geregelt. Weiterentwicklungen der Bewertungsverfahren und die Einführung der Eurocodes führten dazu, dass der DAfStb eine Überarbeitung der bestehenden Richtlinie beschloss. Dieser Beitrag stellt die internationalen Regelungen zu Belastungsversuchen vor und gibt einen Überblick über die bekannten Bewertungsverfahren in verschiedenen Ländern. Neben der Beschreibung der gegenwärtigen deutschen Regeln wird gezeigt, welche Entwicklung die Anwendung von Belastungsversuchen in den USA in den letzten Jahren nahm und welche aktuellen Regeln dort bestehen. An praktischen Beispielen werden die deutschen und amerikanischen Regeln miteinander verglichen und Schlussfolgerungen zu Anforderungen an eine Neufassung der Richtlinie gezogen.

Load testing – international state of the art

For 15 years load testing in Germany is regulated by the guideline of the Deutscher Ausschuss für Stahlbeton (DAfStb). Further research activity resulted in an improvement of the existing evaluation criteria. This and the introduction of the Eurocode into practice led to the need to revise the existing guideline. This paper summarizes the actual international rules for load testing and compares the different existing evaluation criteria. In addition to the description of the german standard, the actual development of the method of load testing in the USA is shown. Practical examples compare the German and American guidelines. It is concluded which requirements are demanded for the amendment of the guideline.
Überführungsbauwerk über die DB‐Strecke Frankfurt‐Fulda bei Hasselroth
Authors: Hauser Holger , Seitz Peter
Published: February 2016

Im Zuge der Beseitigung eines beschrankten Bahnüberganges in der südwestlich von Gelnhausen gelegenen Gemeinde Hasselroth am Rande des Spessarts erfolgte der Neubau einer Umgehungstraße inkl. eines Brückenbauwerks, welches die DB Gleise zukünftig planfrei überführt. Die im Grundriss stark gekrümmte, 7‐feldrige, semi‐integrale Plattenbalkenbrücke wurde im bahnüberspannenden Mittelfeld in Stahlverbundbauweise und in den anschließenden Feldern in Spannbetonbauweise hergestellt. Links und rechts des Hauptfeldes treffen Stahlverbundüberbau, Spannbetonüberbau und die dort integrierten Pfeiler in einem Knotenpunkt zusammen. Aufgrund der äußerst beschränkten Abmessungen und der komplizierten geometrischen Verhältnisse stellte die konstruktive Lösung zur Vereinigung der drei Bauweisen Stahlbeton, Spannbeton und Stahlverbund in einem Punkt eine große Herausforderung für Planung und Ausführung dar.

Railway crossing at Hasselroth – Special detailed design challenges

In order to eliminate a level crossing in the municipality of Hasselroth, a small town located southwest of Gelnhausen at the edge of the Spessart range, a bypass road including a grade‐separated crossing of the railway tracks was constructed. Fitting into a tightly curved alignment, the 7‐span, semi‐integral girder bridge was designed with a steel‐concrete composite cross‐section across the tracks while the other spans are made entirely of prestressed concrete. To either side of the main span the composite and prestressed concrete sections as well as the respective pier are joined into a single node. Due to the complicated geometry the connection of the three sections and materials (reinforced concrete, prestressed concrete and steel‐concrete composite) at a single point posed a very specific structural challenge.
Hochstraße Barkauer Kreuz in Kiel
Authors: Morgen Karl , Süfke Stephan , Keuser Manfred , Braml Thomas
Published: February 2016

Die Hochstraße Barkauer Kreuz wurde 1970/71 als Spannbetonbrücke mit einstegigem Plattenbalkenquerschnitt errichtet. Die Brücke weist sieben Felder mit Stützweiten bis zu 33,15 m und im Grundriss eine starke Krümmung auf. Die Nachrechnung der Brücke in den Stufen 1 und 2 gemäß der Nachrechnungsrichtlinie [1] zeigte, dass nahezu alle Nachweise geführt werden konnten. Lediglich an den Achsen B, C und D zeigten sich Defizite. Daher wurde hier eine Nachrechnung nach Stufe 4 auf der Grundlage einer Finite‐Element‐Berechnung durchgeführt und der Nachweis für Brückenklasse 60 erbracht. Zur Sicherstellung der langfristigen Nutzung wurden Sanierungsarbeiten erforderlich.

Bridge across the Barkauer Crossing in Kiel – Recalculation and rehabilitation of a demanding prestressed concrete bridge

The bridge across the Barkauer crossing was built in 19970/71 as a prestressed concrete bridge with a wide T‐beam cross section. The bridge has seven spans with span widths up to 33.15m and it is extremely curved in the ground section. The recalculation of the bridge on the levels 1 and 2 according to the German recalculation regulations [1] showed good results for most of the parts of the bridge. Deficits were found only in the axes B,C and D. Therefore a recalculation on level 4 was done, based on a FE‐calculation and the proof for bridge class 60 was obtained. For a safe long time use a rehabilitation was necessary.
Parallel β‐sheet vibration band increases with proteins dipole moment under exposure to 1765 MHz microwaves
Authors: Calabrò Emanuele , Magazù Salvatore
Published: February 2016

Effects of exposure of 4 h to mobile phones microwaves at 1765 MHz at a power density around 940 mW/m2on four typical proteins (hemoglobin in H2O solution, and myoglobin, bovine serum albumin, and lysozyme in D2O solution) were studied by means of Fourier Transform Infrared spectroscopy and Fourier self‐deconvolution analysis. Increase in intensity of parallel β‐sheet component around 1635 cm−1was observed after exposure of hemoglobin, myoglobin, and bovine serum albumin, showing that a mechanism of unfolding occurred after exposure, whereas no appreciable change in the amide I region occurred after lysozyme exposure. In addition, a relationship between protein dipole moment and protein unfolding rate was demonstrated with a correlation coefficientr = 0.973 and 95% confidence interval. Bioelectromagnetics. 37:99–107, 2016. © 2016 Wiley Periodicals, Inc.
Discriminated Functional Communication for Attention: Evaluating Fixed and Varied Durations of Reinforcer Availability
Authors: Balka Kaitlin E. , Hausman Nicole L. , Schaller Erin , Kahng SungWoo
Published: February 2016

Discriminated functional communication (DFC) training has been used to teach children to attend to naturally occurring discriminative stimuli when manding for attention. In this study, the participant was taught to only mand for attention during experimenter non‐busy periods. The participant could only discriminate busy and non‐busy activities during more naturalistic varied reinforcer availability periods following prior exposure to a fixed duration of availability. These data suggest that DFC may first have to be taught under more predictable conditions prior to transitioning to more naturalistic conditions. Copyright © 2016 John Wiley & Sons, Ltd.
Expression of exo‐inulinase gene from Aspergillus niger 12 in E. coli strain Rosetta‐gami B (DE3) and its characterization
Authors: Yedahalli Shreyas S. , Rehmann Lars , Bassi Amarjeet
Published: February 2016

Inulin is a linear carbohydrate polymer of fructose subunits (2‐60) with terminal glucose units, produced as carbon storage in selected plants. It cannot directly be taken up by most microorganisms due to its large size, unless prior hydrolysis through inulinase enzymes occurs. The hydrolyzed inulin can be taken up by microbes and/or recovered and used industrially for the production of high fructose syrup, inulo‐oligosaccharides, biofuel, and nutraceuticals. Cell‐free enzymatic hydrolysis would be desirable for industrial applications, hence the recombinant expression, purification and characterization of an Aspergillus niger derived exo‐inulinase was investigated in this study. The eukaroyototic exo‐inulinase of Aspergillus niger 12 has been expressed, for the first time, in an E. coli strain [Rosetta‐gami B (DE3)]. The molecular weight of recombinant exo‐inulinase was estimated to be ∼81 kDa. The values of Km and Vmax of the recombinant exo‐inulinase toward inulin were 5.3 ± 1.1 mM and 402.1 ± 53.1 µmol min−1 mg−1 protein, respectively. Towards sucrose the corresponding values were 12.20 ± 1.6 mM and 902.8 ± 40.2 µmol min−1 mg−1 protein towards sucrose. The S/I ratio was 2.24 ± 0.7, which is in the range of native inulinase. The optimum temperature and pH of the recombinant exo‐inulinase towards inulin was 55°C and 5.0, while they were 50°C and 5.5 towards sucrose. The recombinant exo‐inulinase activity towards inulin was enhanced by Cu2+ and reduced by Fe2+, while its activity towards sucrose was enhanced by Co2+ and reduced by Zn2+. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:629–637, 2016
The influence of a learning to forgive programme on negative affect among mentally disordered offenders
Authors: Mela Mansfield , Baetz Marilyn , Marcoux Gene , Delury Daniel , Cooper Brent , Sajobi Tolulope T.
Published: February 2016

Background

Clinical trials and meta‐analyses provide some evidence for effectiveness of forgiveness therapy delivered individually or in groups. To date, however, forgiveness therapy has not been evaluated with mentally disordered offenders. Given the high prevalence of experienced and perpetrated trauma among such people, this population may particularly benefit from such an intervention.

Aim

The aim of this study is to test the feasibility and impact of a ‘learn to forgive’ group programme among mentally disordered offenders on a specialist secure hospital setting.

Methods

We conducted a non‐randomised trial with 36 offenders with mental disorders and 29 comparison patients. The intervention group engaged in a six‐week manual‐based ‘learn to forgive’ treatment programme, while the comparison group watched a 90‐minute video on forgiveness. Both groups completed measures of anger, depression, stress, forgiveness and satisfaction with life at baseline and then 6 and 18 weeks later. A repeated measures mixed‐effects model was used to investigate the association between affective outcomes and type of intervention received, after adjusting for baseline characteristics.

Results

The group completion rate was over 90%. The treatment and comparison groups were similar on baseline demographic and criminological measures, but the treatment group had higher baseline anger and depression scores. While both groups showed improved capacity to forgive and reduced negative affect over time, those in the ‘learn to forgive’ programme showed significantly more improvement in forgiveness and on anger measures.

Conclusions and implications for practice

Forgiveness training can be delivered effectively to offenders with mental disorders in clinical settings. Its range of benefits, including reduction I in anger as well as improved capacity to forgive, suggest that it may have longer term implications for personal safety and reintegration into mainstream societal settings. Copyright © 2016 John Wiley & Sons, Ltd.
Nonocclusive mesenteric ischemia: fulminant pancolitis
Authors: Kato Kazuya , Iwasaki Yoshiaki , Taniguchi Masahiko , Onodera Kazuhiko , Matsuda Minoru , Tamakawa Susumu , Furukawa Hiroyuki
Published: February 2016

Key Clinical Message

NOMI is mesenteric hypoperfusion with reactive vascular spasms. Changes in the color of the mucosa may reflect the severity of the ischemia of the colon and the severity of prognosis. Even with surgery, the mortality rate is 75%. Diagnosis requires a high degree of clinical suspicion.
Tuning the Electronic Properties of Acetylenic Fluorenes by Phosphaalkene Incorporation
Authors: Svyaschenko Yurii V. , Orthaber Andreas , Ott Sascha
Published: February 2016

Versatile synthetic protocols for 2,7‐ and 3,6‐diacetylenic fluorene‐9‐ylidene phosphanes (F9Ps) were developed. Protodesilylation of trimethylsilyl‐protected acetylenic F9Ps affords terminal acetylenes that can be employed in Sonogashira and Glaser‐type C−C coupling reactions to give thienyl‐decorated and butadiyne‐bridged fluorene‐9‐ylidene phosphanes, respectively. As evidenced by UV/Vis spectroscopy and cyclic voltammetry and corroborated by ab initio calculations, the presence of the P center in the F9Ps induces a significantly reduced HOMO–LUMO splitting that originates from stabilization of the LUMO levels. Variation of the acetylene substitution pattern is an additional tool to influence the optical and electronic properties. Whereas 3,6‐disubstituted F9Ps have strong absorptions around 400 nm, mainly due to π–π* transitions, 2,7‐diacetylenic F9Ps exhibit longest‐wavelength absorptions that have significant charge‐transfer character with an onset around 520 nm.
Highly Regio‐ and Stereoselective Intermolecular Seleno‐ and Thioamination of Alkynes
Authors: Zheng Guangfan , Zhao Jinbo , Li Zhanyu , Zhang Qiao , Sun Jiaqiong , Sun Haizhu , Zhang Qian
Published: February 2016

By using N‐fluorobenzenesulfonimide as both the oxidant and the amination reagent, we have realized the first example of the intermolecular chalcogenative amination of alkynes, which grants facile, highly regio‐ and stereoselective access to chalcogenated enamides. The reaction features mild conditions, high yields and selectivities, remarkably broad substrate scope, and excellent functional group tolerance. Mechanistic studies indicate the in situ generated chalcogen imidates to be the actual reactive species, which in turn, has clarified the mechanism of related transformations. These reactions represent significant additions to the development of the highly selective amino bisfunctionalization of alkynes.
Dual Chemical Modification of a Polytheonamide Mimic: Rational Design and Synthesis of Ion‐Channel‐Forming 48‐mer Peptides with Potent Cytotoxicity
Authors: Hayata Atsushi , Itoh Hiroaki , Matsutaka Shoko , Inoue Masayuki
Published: February 2016

Polytheonamide B (1) is a natural peptide that displays potent cytotoxicity against P388 mouse leukemia cells (IC50=0.098 nm). Linear 48‐mer 1 is known to form monovalent cation channels on binding to lipid bilayers. We previously developed a fully synthetic route to 1, and then achieved the design and synthesis of a structurally simplified analogue of 1, namely, dansylated polytheonamide mimic 2. Although the synthetically more accessible 2 was found to emulate the channel function of 1, its cytotoxicity was decreased 120‐fold. Herein, the chemical preparation and biological evaluation of seven analogues 3–9 of 2 are reported. Compounds 3–9 were modified at their N terminus and/or the side chain of residue 44 of 2 to alter their physicochemical properties. The total synthesis of 3–9 was accomplished in a unified fashion by a combination of solid‐phase and solution‐phase chemistry. Systematic evaluation of the hydrophobicities, single‐channel currents, ion‐exchange activities, and cytotoxicities of 3–9 revealed that their hydrophobicities are correlated with the total magnitude of ion exchange and determine their cytotoxic potency. Consequently, the most hydrophobic analogue 9 exhibited the lowest IC50 value, which is comparable to that of 1. Therefore, these results clarified that the bioactivity of the polytheonamide‐based peptides can be rationally controlled by changing their hydrophobicity at the N and C termini of the 48‐amino‐acid sequence.
Planar Chiral Phosphoramidites with a Paracyclophane Scaffold: Synthesis, Gold(I) Complexes, and Enantioselective Cycloisomerization of Dienynes
Authors: Wu Zhiyong , Isaac Kévin , Retailleau Pascal , Betzer Jean‐François , Voituriez Arnaud , Marinetti Angela
Published: February 2016

The key structural feature of the new phosphoramidites is a paracyclophane scaffold in which two aryl rings are tethered by both a 1,8‐biphenylene unit and a O−P−O bridge. Suitable aryl substituents generate planar chirality. The corresponding gold(I) complexes promote the cycloisomerization of prochiral nitrogen‐tethered dienynes. These reactions afford bicyclo[4.1.0]heptene derivatives displaying three contiguous stereogenic centers, with very high diastereoselectivity and up to 95 % ee.
Facile Synthesis, Characterization, and Catalytic Behavior of a Large‐Pore Zeolite with the IWV Framework
Authors: Schmidt Joel E. , Chen Cong‐Yan , Brand Stephen K. , Zones Stacey I. , Davis Mark E.
Published: February 2016

Large‐pore microporous materials are of great interest to process bulky hydrocarbon and biomass‐derived molecules. ITQ‐27 (IWV) has a two‐dimensional pore system bounded by 12‐membered rings (MRs) that lead to internal cross‐sections containing 14 MRs. Investigations into the catalytic behavior of aluminosilicate (zeolite) materials with this framework structure have been limited until now due to barriers in synthesis. The facile synthesis of aluminosilicate IWV in both hydroxide and fluoride media is reported herein using simple, diquaternary organic structure‐directing agents (OSDAs) that are based on tetramethylimidazole. In hydroxide media, a zeolite product with Si/Al=14.8–23.2 is obtained, while in fluoride media an aluminosilicate product with Si/Al up to 82 is synthesized. The material produced in hydroxide media is tested for the hydroisomerization of n‐hexane, and results from this test reaction suggest that the effective pore size of zeolites with the IWV framework structure is similar to but slightly larger than that of ZSM‐12 (MTW), in fairly good agreement with crystallographic data.
A Versatile CuII Metal–Organic Framework Exhibiting High Gas Storage Capacity with Selectivity for CO2: Conversion of CO2 to Cyclic Carbonate and Other Catalytic Abilities
Authors: De Dinesh , Pal Tapan K. , Neogi Subhadip , Senthilkumar S. , Das Debasree , Gupta Sayam Sen , Bharadwaj Parimal K.
Published: February 2016

A linear tetracarboxylic acid ligand, H4L, with a pendent amine moiety solvothermally forms two isostructural metal–organic frameworks (MOFs) LM (M=ZnII, CuII). Framework LCu can also be obtained from LZn by post‐ synthetic metathesis without losing crystallinity. Compared with LZn, the LCu framework exhibits high thermal stability and allows removal of guest solvent and metal‐bound water molecules to afford the highly porous, LCu′. At 77 K, LCu′ absorbs 2.57 wt % of H2 at 1 bar, which increases significantly to 4.67 wt % at 36 bar. The framework absorbs substantially high amounts of methane (238.38 cm3 g−1, 17.03 wt %) at 303 K and 60 bar. The CH4 absorption at 303 K gives a total volumetric capacity of 166 cm3 (STP) cm−3 at 35 bar (223.25 cm3 g−1, 15.95 wt %). Interestingly, the NH2 groups in the linker, which decorate the channel surface, allow a remarkable 39.0 wt % of CO2 to be absorbed at 1 bar and 273 K, which comes within the dominion of the most famous MOFs for CO2 absorption. Also, LCu′ shows pronounced selectivity for CO2 absorption over CH4, N2, and H2 at 273 K. The absorbed CO2 can be converted to value‐added cyclic carbonates under relatively mild reaction conditions (20 bar, 120 °C). Finally, LCu′ is found to be an excellent heterogeneous catalyst in regioselective 1,3‐dipolar cycloaddition reactions (“click” reactions) and provides an efficient, economic route for the one‐pot synthesis of structurally divergent propargylamines through three‐component coupling of alkynes, amines, and aldehydes.