bluuebunny/crossref_metadata_2025_split huggingface dataset:
Visible‐Light‐Responsive Reversible Photoacid Based on a Metastable Carbanion
Authors: Johns Valentine K. , Peng Ping , DeJesus Joseph , Wang Zhuozhi , Liao Yi 
Published: December 2013

AbstractA new photoacid that reversibly changes from a weak to a strong acid under visible light was designed and synthesized. Irradiation generated a metastable state with high CH acidity due to high stability of a trifluoromethyl‐phenyl‐tricyano‐furan (CF3PhTCF) carbanion. This long‐lived metastable state allows a large proton concentration to be reversibly produced with moderate light intensity. Reversible pH change of about one unit was demonstrated by using a 0.1 mM solution of the photoacid in 95 % ethanol. The quantum yield was calculated to be as high as 0.24. Kinetics of the reverse process can be fitted well to a second‐order‐rate equation with k=9.78×102 M−1 s−1. Response to visible light, high quantum yield, good reversibility, large photoinduced proton concentration under moderate light intensity, and good compatibility with organic media make this photoacid a promising material for macroscopic control of proton‐transfer processes in organic systems.
Mikrowellen in der Organischen Synthese
Authors: Dallinger Doris 
Published: December 2013

AbstractDas kontrollierte Mikrowellen‐Heizen, besonders die Variante in geschlossenen Reaktionsgefäßen, bietet viele Vorzüge gegenüber traditionell beheizten Synthesen. Schnellere Reaktionszeiten, höhere Ausbeuten und bessere Reproduzierbarkeit zählen wohl zu den Wichtigsten. Außerdem kann die Mikrowellensynthese leicht an eine parallele oder automatisierte sequenzielle Arbeitsweise angepasst werden. Aufgrund der einfachen Handhabung der Mikrowellentechnologie und der Tatsache, dass man für eine bestimmte chemische Umwandlung binnen 5–10 Minuten ein aussagekräftiges Ergebnis (“Ja” oder “Nein”) erhalten kann, wird diese neuartige Heizmethode bereits an vielen Universitäten und in der Industrie vor allem zur schnellen Reaktionsoptimierung und zur effizienten Synthese neuer Verbindungen genutzt.
Digitalfotografie in der Chemie
Authors: Diemann Ekkehard 
Published: December 2013

AbstractDer Einsatz von kompakten Digitalkameras am Mikroskop und von Flachbettscannern zur Abbildung von Objekten aus der Chemie wird beschrieben. Der Schwerpunkt liegt dabei auf allgemein verfügbaren und kostengünstigen Lösungen, die zu brauchbaren Resultaten führen.
Distinctive population of Gfap‐expressing neural progenitors arising around the dentate notch migrate and form the granule cell layer in the developing hippocampus
Authors: Seki Tatsunori , Sato Toru , Toda Keiko , Osumi Noriko , Imura Tetsuya , Shioda Seiji 
Published: December 2013

ABSTRACTIn the adult hippocampus, granule cells continue to be generated from astrocyte‐like progenitors expressing glial fibrillary acidic protein (GFAP) that differ from embryonic neocortical progenitors. However, during the embryonic period, dentate granule neurons and neocortical pyramidal neurons are derived from the ventricular zone (VZ) of the pallium. Our question is when do GFAP+ progenitors of granule neurons appear in the developing hippocampus during the embryonic period, and how do they form the granule cell layer. The present analysis using Gfap‐GFP transgenic mice shows that the GFP+ distinct cell population first appears in the VZ of the medial pallium at the dorsal edge of the fimbria on embryonic day 13.5. During the perinatal period, they form a migratory stream from the VZ to the developing dentate gyrus, and establish the germinal zones in the migratory stream, and the marginal and hilar regions in the developing dentate gyrus. GFP+ cells in these regions were positive for Sox2 and Ki67, but negative for BLBP. GFP+ cells with Neurogenin2 expression were largely distributed in the VZ, whereas GFP+ cells with Tbr2 and NeuroD expressions were seen in the migratory stream and developing dentate gyrus. Prox1‐expressing GFP+ cells were restricted to the developing dentate gyrus. These results suggest that distinctive Gfap‐expressing progenitors arising around the dentate notch form germinal regions in the migratory stream and the developing dentate gyrus where they differentiate into granule neurons, indicating that distinct astrocyte‐like neural progenitors continue to generate granule neurons, from the beginning of dentate development and throughout life. J. Comp. Neurol. 522:261–283, 2014. © 2013 Wiley Periodicals, Inc.
Interionic Interactions in Conducting Nanoconfinement
Authors: Rochester Christopher C. , Lee Alpha A. , Pruessner Gunnar , Kornyshev Alexei A. 
Published: December 2013

AbstractInterionic interactions in conducting nanopores determine how counterions may be packed in the pores subject to the applied voltage. In ideal metals, interactions are exponentially screened by metallic electrons. However, modern nanoporous electrodes are predominantly made of carbon materials. To what extent is this screening affected by a different mode of dielectric response in such materials? To answer this question we study Coulomb interaction of charges in cylindrical and slit pores that allow finite electric field penetration into the pore walls, as well as the Coulomb interaction in a nanogap between two thin walls of graphene modeled by a non‐local dielectric function. In all cases studied the screening was found to be subtly different than in metallic nanopores, but still strong enough to support realization of the so called superionic state in such pores.
Structurally Stabilized Organosilane‐Templated Thermostable Mesoporous Titania
Authors: Amoli Vipin , Tiwari Rashmi , Dutta Arghya , Bhaumik Asim , Sinha Anil Kumar 
Published: December 2013

AbstractStructurally thermostable mesoporous anatase TiO2 (m‐TiO2) nanoparticles, uniquely decorated with atomically dispersed SiO2, is reported for the first time. The inorganic Si portion of the novel organosilane template, used as a mesopores‐directing agent, is found to be incorporated in the pore walls of the titania aggregates, mainly as isolated sites. This is evident by transmission electron microscopy and high‐angle annular dark field scanning transmission electron microscopy, combined with electron dispersive X‐ray spectroscopy. This type of unique structure provides exceptional stability to this new material against thermal collapse of the mesoporous structure, which is reflected in its high surface area (the highest known for anatase titania), even after high‐temperature (550 °C) calcination. Control of crystallite size, pore diameter, and surface area is achieved by varying the molar ratios of the titanium precursor and the template during synthesis. These mesoporous materials retain their porosity and high surface area after template removal and further NaOH/HCl treatment to remove silica. We investigate their performance for dye‐sensitized solar cells (DSSCs) with bilayer TiO2 electrodes, which are prepared by applying a coating of m‐TiO2 onto a commercial titania (P25) film. The high surface area of the upper mesoporous layer in the P25–m‐TiO2 DSSC significantly increases the dye loading ability of the photoanode. The photocurrent and fill factor for the DSSC with the bilayer TiO2 electrode are greatly improved. The large increase in photocurrent current (ca. 56 %) in the P25–m‐TiO2 DSSC is believed to play a significant role in achieving a remarkable increase in the photovoltaic efficiency (60 %) of the device, compared to DSSCs with a monolayer of P25 as the electrode.
Collective Phenomena in Strongly Coupled Dissipative Systems of Charged Dust: from Ground to Microgravity Experiments
Authors: Petrov O. F. , Fortov V. E. 
Published: December 2013

AbstractIn present work the formation of dusty plasma structures in cryogenic glow dc discharge was investigated. The ordered structures from large number (∼104) of charged diamagnetic dust particles in a cusp magnetic trap have been also studied in microgravity conditions. The super high charging (up to 5·107e) of dust macroparticles under direct stimulation by an electron beam is experimentally performed and investigated. The results of the investigation of Brownian motion for strongly coupled dust particles in plasma are presented. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Laser Driven Electron‐Positron Pair Creation–Kinetic Theory Versus Analytical Approximations
Authors: Smolyansky S. A. , Bonitz M. , Prozorkevich A. V. 
Published: December 2013

AbstractThe dynamical Schwinger effect of vacuum pair creation driven by an intense external laser pulse is studied on the basis of quantum kinetic theory. The numerical solutions of these kinetic equations exhibit a complex time dependence which makes an analysis of the physical processes difficult. In particular, the question of secondary effects, such as creation of secondary annihilation photons from the focus spot of the colliding laser beams, remains an important open problem. In the present work we, therefore, develop a perturbation theory which is able to capture the dominant time dependence of the produced electron‐positron pair density. The theory shows excellent agreement with the exact kinetic results during the laser pulse, but fails to reproduce the residual pair density remaining in the system after termination of the pulse. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
IF: isolating fault nodes with mobile scanner
Authors: Xiao Xiangrong , Hu Dewen , Guo Deke , Liu Kebin 
Published: December 2013

SUMMARYFault diagnosis plays an important role on stable applications maintaining in wireless sensor networks (WSNs). Most existing researchers are concerned about the statics nodes‐based diagnosis techniques, which are incompetent to cope with those dynamically occurring faults. In this paper, we propose a novel mechanism isolating fault (IF) nodes that employs the mobile node as a scanner to diagnose the faults in WSNs. The mobile scanner can detect the fault nodes within its communication region by using sniffer. It can also control the transmitting route of nodes by modifying their links. Starting from the base station, the mobile scanner periodically selects and visits all monitoring stations and consequently explores all static nodes in the monitoring area. After detecting a fault node, the mobile scanner will prevent it from connecting to the other normal nodes. We aim at finding the least number of monitoring stations and discovering an optimal route. We first formulate the two research issues to hitting set problem and travel salesperson problem. We then solve these two nondeterministic polynomial time hard problems by proposing an approximate algorithm, weighted, and hierarchical IF, which only uses local information. The mobile scanner makes a decision by weighing both the significance and the priority of nodes level by level. The proposed mechanism IF maintains the stabile service of WSNs in a transparent manner. The simulation results show that our algorithm can effectively isolate fault nodes, alleviate the damages of network corrupting, and hence increase the resilience of WSNs. Copyright © 2013 John Wiley & Sons, Ltd.
Perinatal maternal stress and serotonin signaling: Effects on pain sensitivity in offspring
Authors: Knaepen Liesbeth , Pawluski Jodi L. , Patijn Jacob , van Kleef Maarten , Tibboel Dick , Joosten Elbert A. 
Published: December 2013

ABSTRACTIt has been estimated that 20% of pregnant women are facing perinatal stress and depression. Perinatal maternal stress has been shown to increase pain sensitivity in offspring. For the treatment of their depressive symptoms, pregnant women are frequently prescribed selective serotonin reuptake inhibitors (SSRIs). Since the descending pain inhibitory circuit matures perinatally, perinatal SSRI exposure has been shown to affect pain sensitivity in offspring. In the present review, we summarize experimental and clinical evidence for the effect of perinatal maternal stress and SSRI exposure on pain sensitivity in offspring. Both experimental and clinical studies show the effect of perinatal maternal stress on regulation of the hypothalamic–pituitary–adrenal (HPA) system and the serotonin pain inhibitory system. Alterations in these two systems likely underlie long‐term alterations in the development of pain sensitivity. This review sheds light on the effect of perinatal maternal stress and treatment with SSRIs on offspring pain sensitivity, in relation to the developing HPA system and 5‐HT signaling. © 2013 Wiley Periodicals, Inc. Dev Psychobiol 56: 885–896, 2014.
Rainfall partitioning, tree form and measurement scale: a comparison of two co‐occurring, morphologically distinct tree species in a semi‐arid environment
Authors: Swaffer Brooke A , Holland Kate L , Doody Tanya M , Hutson John 
Published: December 2013

ABSTRACTThe partitioning of precipitation into interception, stemflow and throughfall is an important hydrological process in forested systems, influenced heavily by climate and plant form. This study examined whether the rainfall partitioning pathways reflect the often cited influence of tree morphology, using two species in a semi‐arid karst environment. Eucalyptus diversifolia ssp. diversifolia has a multi‐stemmed habit, smooth bark and true leaves. In comparison, Allocasuarina verticillata has a single trunk, rough bark and long, thin, vertical phyllodes. We hypothesized that multiple stems and a smooth bark would be more effective at generating stemflow compared with single stems with a rough bark surface. To test this, rainfall, throughfall and stemflow were collected over two years, and stemflow funnelling ratios were calculated. The degree of similarity in overall rainfall partitioning for the two species was remarkable; although some divergence was found each month, the partitioning regressions converged. For E. diversifolia, gross rainfall partitioned into interception, throughfall and stemflow averaged 30.9%, 66.4% and 2.7%, respectively. For A. verticillata, rainfall partitioning of gross precipitation into interception, throughfall and stemflow averaged 31.4%, 65.9% and 2.7%, respectively. Maximum stemflow funnelling ratio for E. diversifolia was 74 and for A. verticillata was 147, indicating that water from stemflow is likely to play an important ecohydrological role in this environment. We further compared these findings to 31 global studies and discussed the importance of scale (individual tree vs plot) and canopy cover when reporting or interpreting rainfall partitioning results. Copyright © 2013 John Wiley & Sons, Ltd.
Phase‐Controlled Deposition of Copper Sulfide Thin Films by Using Single‐Molecular Precursors
Authors: Ashraf Saba , Saeed Aamer , Malik Mohammad Azad , Flörke Ulrich , Bolte Michael , Haider Naghmah , Akhtar Javeed 
Published: December 2013

AbstractHerein, we describe the synthesis and characterization of new ligands, N,N‐diethyl‐N′‐(1‐naphthoyl)thiourea (1a) and N,N‐dipropyl‐N′‐(1‐naphthoyl)thiourea (1b), and their complexes with copper, bis[N,N‐diethyl‐N′‐(1‐naphthoyl)thioureato]CuII (2a) and bis[N,N‐dipropyl‐N′‐(1‐naphthoyl)thioureato]CuII (2b). All four compounds (i.e., 1a, 1b, 2a, and 2b) were characterized by elemental analysis, 1H NMR and 13C NMR spectroscopy, and FTIR spectroscopy. The structures of compounds 1a, 1b, and 2b were determined by single‐crystal X‐ray diffraction analysis. Thermogravimetric analysis of 2a and 2b showed that both compounds decompose between 190 and 370 °C. Compounds 2a and 2b were then used as single‐molecular precursors for the deposition of copper sulfide thin films through aerosol‐assisted chemical vapor deposition. The phase and purity of the as‐deposited thin films were confirmed by powdered X‐ray diffraction, which showed that the as‐grown films were composed of the orthorhombic (Cu7S4) phase only. Morphological studies of the as‐deposited films were performed by using field‐emission scanning electron microscopy. The elemental composition of the thin films was determined by energy‐dispersive X‐ray spectroscopy.
Zebrafish as a model system to study toxicology
Authors: Dai Yu-Jie , Jia Yong-Fang , Chen Na , Bian Wan-Ping , Li Qin-Kai , Ma Yan-Bo , Chen Yan-Ling , Pei De-Sheng 
Published: December 2013

Abstract

Monitoring and assessing the effects of contaminants in the aquatic eco-environment is critical in protecting human health and the environment. The zebrafish has been widely used as a prominent model organism in different fields because of its small size, low cost, diverse adaptability, short breeding cycle, high fecundity, and transparent embryos. Recent studies have demonstrated that zebrafish sensitivity can aid in monitoring environmental contaminants, especially with the application of transgenic technology in this area. The present review provides a brief overview of recent studies on wild-type and transgenic zebrafish as a model system to monitor toxic heavy metals, endocrine disruptors, and organic pollutants for toxicology. The authors address the new direction of developing high-throughput detection of genetically modified transparent zebrafish to open a new window for monitoring environmental pollutants. Environ Toxicol Chem 2014;33:11–17. © 2013 SETAC
Modeling the contribution of toxicokinetic and toxicodynamic processes to the recovery of Gammarus pulex populations after exposure to pesticides
Authors: Galic Nika , Ashauer Roman , Baveco Hans , Nyman Anna-Maija , Barsi Alpar , Thorbek Pernille , Bruns Eric , Van den Brink Paul J. 
Published: December 2013

Abstract

Because aquatic macroinvertebrates may be exposed regularly to pesticides in edge-of-the-field water bodies, an accurate assessment of potential adverse effects and subsequent population recovery is essential. Standard effect risk assessment tools are not able to fully address the complexities arising from multiple exposure patterns, nor can they properly address the population recovery process. In the present study, we developed an individual-based model of the freshwater amphipod Gammarus pulex to evaluate the consequences of exposure to 4 compounds with different modes of action on individual survival and population recovery. Effects on survival were calculated using concentration–effect relationships and the threshold damage model (TDM), which accounts for detailed processes of toxicokinetics and toxicodynamics. Delayed effects as calculated by the TDM had a significant impact on individual survival and population recovery. We also evaluated the standard assessment of effects after short-term exposures using the 96-h concentration–effect model and the TDM, which was conservative for very short-term exposure. An integration of a TKTD submodel with a population model can be used to explore the ecological relevance of ecotoxicity endpoints in different exposure environments. Environ Toxicol Chem 2014;33:1476–1488. © 2014 SETAC
Chemiluminescent examination of abiotic oxidative stress of watercress
Authors: Beals Christopher , Byl Thomas 
Published: December 2013

Abstract

Watercress (Nasturtium officinale) is an aquatic plant that readily bioaccumulates heavy metals that may be found in contaminated aquatic systems. Toxic effects of contaminants on the physiological processes cause changes in oxidase enzymatic activity in watercress, which can be measured with a luminometer. The luminometer uses the reaction produced when peroxidases break down hydrogen peroxide into water and an oxygen radical. The resulting oxyradical binds to and oxidizes phenolic groups, producing a measureable luminescent reaction. Nasturtium officinale plants were exposed to 3 different concentrations of heavy metals, including lead, nickel, copper, and manganese for 24 h, 48 h, and 72 h. Aquatic exposure to the 4 heavy metals caused a significant increase in oxidative enzyme production. Fluorometric and morphometric measurements were also conducted to compare plant stress with the oxidative enzyme analyses. Fluorometric measurements performed on plants stressed by exposure to heavy metals revealed no significant decreases in photosystem II efficiency. Morphometric measurements of root length showed decreased root growth resulting from exposures to Ni, Cu, and Mn. Environ Toxicol Chem 2014;33:798–803. © 2013 SETAC
Regional models for sediment toxicity assessment
Authors: Field L. Jay , Norton Susan B. 
Published: December 2013

Abstract

The present study describes approaches to improve the performance of empirical models developed from a large nationwide data set to predict sediment toxicity from chemistry for regional applications. The authors developed 4 multiple chemical (PMax) models selected from individual chemical models developed using 1) a previously published approach applied to the nationwide data set; 2) a broader array of response and explanatory variables (e.g., different normalization approaches and toxicity classifications) applied to the nationwide data set; 3) a data set from the New York/New Jersey, USA, region; and 4) both nationwide and regional data sets. The models were calibrated using the regional data set. Performance was tested using an independent data set from the same region. The performance of the final PMax model developed using the calibration process substantially improved over that of the uncalibrated PMax model developed using the nationwide data set. The improvements were achieved by selecting the best performing individual chemical models and eliminating those that performed poorly when applied together. Although the best performing PMax model included both nationwide and region-specific models, the performance of the PMax model derived using only nationwide models was nearly as good. These results suggest that calibrating nationwide models to a regional data set may be both a more efficient and effective approach for improving model performance than developing region-specific models. Environ Toxicol Chem 2014;33:708–717. © 2013 SETAC. This article is a US Government work and is in the public domain in the USA.
High Molecular Weight Polybenzimidazole Membranes for High Temperature PEMFC
Authors: Yang J. S. , Cleemann L. N. , Steenberg T. , Terkelsen C. , Li Q. F. , Jensen J. O. , Hjuler H. A. , Bjerrum N. J. , He R. H. 
Published: December 2013

AbstractHigh temperature operation of proton exchange membrane fuel cells under ambient pressure has been achieved by using phosphoric acid doped polybenzimidazole (PBI) membranes. To optimize the membrane and fuel cells, high performance polymers were synthesized of molecular weights from 30 to 94 kDa with good solubility in organic solvents. Membranes fabricated from the polymers were systematically characterized in terms of oxidative stability, acid doping and swelling, conductivity, mechanical strength and fuel cell performance and durability. With increased molecular weights the polymer membranes showed enhanced chemical stability towards radical attacks under the Fenton test, reduced volume swelling upon the acid doping and improved mechanical strength at acid doping levels of as high as about 11 mol H3PO4 per molar repeat polymer unit. The PBI‐78kDa/10.8PA membrane, for example, exhibited tensile strength of 30.3 MPa at room temperature or 7.3 MPa at 130 °C and a proton conductivity of 0.14 S cm–1 at 160 °C. Fuel cell tests with H2 and air at 160 °C showed high open circuit voltage, power density and a low degradation rate of 1.5 μV h–1 at a constant load of 300 mA cm–2.