bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact of semidiurnal tidal variability during SSWs on the mean state of the ionosphere and thermosphere
Authors: Pedatella N. M. , Richmond A. D. , Maute A. , Liu H.‐L.
Published: August 2016

Observations from the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) satellites reveal a global reduction in the zonal and diurnal mean F region peak electron density (NmF2) during sudden stratosphere warmings (SSWs). The present study investigates the source of the global NmF2 decrease by performing numerical experiments with the National Center for Atmospheric Research (NCAR) thermosphere‐ionosphere‐electrodynamics general circulation model. The simulations reveal that the NmF2 reduction coincides with a depletion of thermospheric [O]/[N2], indicating that the NmF2 depletion is related to changes in thermospheric composition during SSWs. Numerical experiments further illustrate that the short‐term (∼10 day) enhancement of the migrating semidiurnal solar tide (SW2) during SSWs is the source of the variability in thermospheric composition. In particular, the enhancement of the SW2 during SSWs alters the lower thermosphere zonal mean circulation, leading to a reduction in atomic oxygen in the lower thermosphere. The atomic oxygen reduction propagates into the upper thermosphere through molecular diffusion, leading to a decrease in [O]/[N2] throughout the low‐ to middle‐latitude thermosphere. It is anticipated that the effects of the SW2 on the ionosphere and thermosphere investigated herein will be modulated by SSW related enhancements of the migrating semidiurnal lunar tide (M2). The magnitude of the combined impact of the SW2 and M2 on the ionosphere‐thermosphere mean state will depend on the relative phasing of the solar and lunar tides. The results demonstrate that in addition to modulating the low‐latitude electrodynamics, tidal variability during SSWs can significantly impact the mean state of the ionosphere and thermosphere.
Modeling hydrological controls on variations in peat water content, water table depth, and surface energy exchange of a boreal western Canadian fen peatland
Authors: Mezbahuddin M. , Grant R. F. , Flanagan L. B.
Published: August 2016

Improved predictive capacity of hydrology and surface energy exchange is critical for conserving boreal peatland carbon sequestration under drier and warmer climates. We represented basic processes for water and O2 transport and their effects on ecosystem water, energy, carbon, and nutrient cycling in a process‐based model ecosys to simulate effects of seasonal and interannual variations in hydrology on peat water content, water table depth (WTD), and surface energy exchange of a Western Canadian fen peatland. Substituting a van Genuchten model (VGM) for a modified Campbell model (MCM) in ecosys enabled a significantly better simulation of peat moisture retention as indicated by higher modeled versus measured R2 and Willmot's index (d) with VGM (R2~0.7, d~0.8) than with MCM (R2~0.25, d~0.35) for daily peat water contents from a wetter year 2004 to a drier year 2009. With the improved peat moisture simulation, ecosys modeled hourly WTD and energy fluxes reasonably well (modeled versus measured R2: WTD ~0.6, net radiation ~0.99, sensible heat >0.8, and latent heat >0.85). Gradually declining ratios of precipitation to evapotranspiration and of lateral recharge to discharge enabled simulation of a gradual drawdown of growing season WTD and a consequent peat drying from 2004 to 2009. When WTD fell below a threshold of ~0.35 m below the hollow surface, intense drying of mosses in ecosys caused a simulated reduction in evapotranspiration and an increase in Bowen ratio during late growing season that were consistent with measurements. Hence, using appropriate water desorption curve coupled with vertical‐lateral hydraulic schemes is vital to accurately simulate peatland hydrology and energy balance.
From White to Red: Electric‐Field Dependent Chromaticity of Light‐Emitting Electrochemical Cells based on Archetypal Porphyrins
Authors: Weber Michael D. , Wittmann Judith E. , Burger Alexandra , Malcıoğlu Osman Barış , Segarra‐Martí Javier , Hirsch Andreas , Coto Pedro B. , Bockstedte Michel , Costa Rubén D.
Published: August 2016

The differences in the electroluminescence (EL) of red‐emitting free‐base (H2TPP) and Zn‐metalated (ZnTPP) archetypal porphyrins are rationalized in light‐emitting electrochemical cells by means of an electric‐field dependent effect, leading to whitish and reddish devices, respectively. Although H2TPP shows superior electrochemical and photophysical features compared to ZnTPP, devices prepared with ZnTPP surprisingly stand out with a deep‐red EL similar to its photoluminescence (PL), while H2TPP devices feature unexpected whitish EL. Standard arguments such as degradation, device architecture, device mechanism, and changes in the nature of the emitting excited states are discarded. Based on electrochemical impedance spectroscopy and first‐principles electronic structure methods, we provide evidence that the EL originates from two H2TPP regioisomers, in which the inner ring H atoms are placed in collinear and vicinal configurations. The combination of their optical features provides an explanation for both the high‐ and low‐energy EL features. Here, the emitting excited state nature is ascribed to the Q bands, since the Soret excited states remain high in energy. This contrasts to what is traditionally postulated in reports focused on H2TPP lighting devices. Hence, this work provides a new explanation for the nature of the high‐energy EL band of H2TPP that might inspire future works focused on white‐emitting molecular‐based devices.
How Can One Controllably Use of Natural ΔpH in Polyelectrolyte Multilayers?
Authors: Skorb Ekaterina V. , Möhwald Helmuth , Andreeva Daria V.
Published: August 2016

Most natural and synthetic polyelectrolytes (PEs) possess dissociable groups, and therefore the corresponding structures depend on pH. This enables manipulation of their properties, in special permeability, elasticity and swelling, and this can be made use of in many applications. The effect of individual polymer composition on the dissociation equilibrium is discussed. Different concentrations and pH values during the PE assembly affect concentration of charged groups per molecule on the dissociation equilibrium. Ionic strength also influences the protonation/deprotonation behavior of PE, that can be changed by adding different salt concentration but also varies with the concentration of charged groups in the polymer molecules. Electrostatic interactions of the polymer molecules strongly affect the dissociation equilibrium of weak PEs and, thus, layers architecture and properties that can be regulated by natural pH changes in such processes as self‐healing, corrosion and antifouling, drug storage and delivery, etc.
Kevlar‐Based Supercapacitor Fibers with Conformal Pseudocapacitive Metal Oxide and Metal Formed by ALD
Authors: Daubert James S. , Mundy J. Zachary , Parsons Gregory N.
Published: August 2016

Kevlar, poly(p‐phenylene terephthalamide) (PPTA), yarns are modified for use as flexible supercapacitor electrodes by coating them with a nanometer‐scale film of conductive platinum metal and pseudocapacitive V2O5 using atomic layer deposition (ALD). The PPTA yarns are incorporated into a solid‐state supercapacitor through the use of a polyvinyl alcohol/lithium chloride gel electrolyte. Pseudocapacitive V2O5 films 11 nm thick provide up to a 5× increase in areal capacitance (18.4 mF cm−2) over the Pt‐only‐coated PPTA. Thicker films of V2O5 and wrapping the electrodes together into a single yarn result in decreased areal capacitance due to charge‐transfer limitations. The work describes how ALD metal and metal oxide can be combined to add double layer and pseudocapacitive charge storage to mechanically robust PPTA creating unique multifunctional electronic fabric device systems.
Titanium Dioxide/Lithium Phosphate Nanocomposite Derived from Atomic Layer Deposition as a High‐Performance Anode for Lithium Ion Batteries
Authors: Wang Biqiong , Liu Jian , Sun Qian , Xiao Biwei , Li Ruying , Sham Tsun‐Kong , Sun Xueliang
Published: August 2016

Atomic layer deposition (ALD) is considered as a powerful technique to synthesize novel electrode materials for lithium‐ion batteries (LIBs), because not only the compositions can be specifically designed to achieve higher battery performances, but also the materials can be deposited on various substrates for different purposes. Herein, a novel design of active material/electrolyte mixture electrode, i.e., titanium dioxide/lithium phosphate (TLPO) nanocomposite, has been successfully developed by ALD and deposited on carbon nanotube substrates (CNTs@TLPO) at 250 °C, by combining the ALD recipes of TiO2 and lithium phosphate (LPO). In the nanocomposite, TiO2 forms anatase nanocrystals, embedded in a matrix of amorphous lithium phosphate. CNTs@TLPO has been examined as an anode material for LIBs, exhibiting a similar electrochemical response as anatase TiO2 in the cyclic voltammetry testing. CNTs@TLPO presents an outstanding capacity of 204 mA h g−1 upon 200 cycles in charge and discharge cycling measurements, as well as a significantly improved rate capability compared with ALD deposited TiO2 on CNTs without LPO ALD cycles. This work shows that the in situ addition of solid‐state electrolyte (e.g., lithium phosphate), which introduces higher Li+ ionic conductivity, is an efficient way to achieve high‐performance electrode materials for LIBs by ALD.
Self‐Assembled Magnetite Mesocrystalline Films: Toward Structural Evolution from 2D to 3D Superlattices
Authors: Brunner J. , Baburin I. A. , Sturm S. , Kvashnina K. , Rossberg A. , Pietsch T. , Andreev S. , Sturm (née Rosseeva) E. , Cölfen H.
Published: August 2016

This study describes synthesis and detailed characterization of 2D and 3D mesocrystalline films produced by self‐assembly of iron oxide (magnetite) truncated nanocubes. The orientational relations between nanocrystals within the superlattice are examined and atomistic models are introduced. In the 2D case, two distinct superstructures (i.e., translational order) of magnetite nanocubes can be observed with p4mm and c2mm layer symmetries while maintaining the same orientational order (with [100]magnetite perpendicular to the substrate). The 3D structure can be approximated by a slightly distorted face‐centered cubic (fcc) superlattice. The most efficient space filling within the 3D superstructure is achieved by changing the orientational order of the nanoparticles and following the “bump‐to‐hollow” packing principle. Namely orientational order is determined by the shape of the nanoparticles with the following orientational relations: [001]SL||[310]magnetite, [001]SL||[301]magnetite, [001]SL||[100]magnetite. Overall the presented data provide a fundamental understanding of a mesocrystal formation mechanism and their structural evolution. Structure, composition, and magnetic properties of the synthesised nanoparticles are also characterized.
Highly Efficient Laser Scribed Graphene Electrodes for On‐Chip Electrochemical Sensing Applications
Authors: Nayak Pranati , Kurra Narendra , Xia Chuan , Alshareef Husam N.
Published: August 2016

This study reports the fabrication of flexible electrochemical sensors using a direct‐write laser scribing process that transforms commercial polyimide sheet into graphitic carbon with self‐standing porous 3D morphology, and abundant edge planes. The heterogeneous electron transfer rate (k0) of the laser scribed graphene (LSG) electrodes for both inner‐sphere and outer‐sphere redox mediators, ferrocyanide ([Fe(CN)6]4−) and hexaammineruthenium ([Ru(NH3)6]3+) are estimated to be 0.1150 and 0.0868 cm s−1, respectively. These values are significantly higher than those for similar carbon based materials, which this study ascribes to the binder free 3D porous network of LSG with enriched edge plane sites. Further, k0 is enhanced up to 0.2823 and 0.2312 cm s−1 for inner and outer‐sphere redox mediators by selective anchoring of Pt nanoparticles over LSG. The LSG electrodes exhibit significantly improved electrocatalytic activity toward oxidation of ascorbic acid (AA), dopamine (DA), and uric acid (UA). Consequently, the detection of these biomarkers is achieved with high sensitivity of 237.76 and 250.69 μA mm−1 cm−2 (AA), 2259.9 and 6995.6 μA mm−1 cm−2 (DA) and 5405 and 8289 μA mm−1 cm−2 (UA) for LSG and Pt/LSG electrodes, respectively, in a wide concentration range. These results outperform previously reported 2D/3D graphene based electrodes.
Nanowire Array Structures for Photocatalytic Energy Conversion and Utilization: A Review of Design Concepts, Assembly and Integration, and Function Enabling
Authors: Hoang Son , Gao Pu‐Xian
Published: August 2016

The increasing human demand for clean and renewable energy and a cleaner environment has stimulated various materials related research and development for efficient solar energy conversion and utilization, photocatalytic environmental remediation, and photoassisted selective conversion of organic compounds. Among the various candidate solutions to improving the efficiency of these processes, semiconductor nanowire (NW) and nanorod (NR) array structures have been offering a unique tool box combining desirable characteristics in structure, function, and applicability. Efficient photocatalytic energy conversion requires excellent light absorption, readily charge separation, transport, and collection, as well as fast kinetics of interfacial reactions and mass transport of reactants. The long axis of the NW enables adequate light absorption, while the radical axis provides short electron–hole separation distance. Additionally, the NW arrays have relatively high surface area to facilitate interfacial kinetics while their open pore structure allows good mass transport properties. This study reviews the current status of research on NW and NR array structures of some most popular semiconducting materials for photocatalytic energy conversion and utilization including photocatalytic water splitting and CO2 reduction/fixation, dye/quantum dot sensitized solar cells, and other photoassisted reactive applications such as pollutant degradation, selective conversion of organic compounds, and biological disinfection.
Wood Composite as an Energy Efficient Building Material: Guided Sunlight Transmittance and Effective Thermal Insulation
Authors: Li Tian , Zhu Mingwei , Yang Zhi , Song Jianwei , Dai Jiaqi , Yao Yonggang , Luo Wei , Pastel Glenn , Yang Bao , Hu Liangbing
Published: August 2016

Among many other requirements, energy efficient building materials require effective daylight harvesting and thermal insulation to reduce electricity usage and weatherization cost. The most commonly used daylight harvesting material, glass, has limited light management capability and poor thermal insulation. For the first time, transparent wood is introduced as a building material with the following advantages compared with glass: (1) high optical transparency over the visible wavelength range (>85%); (2) broadband optical haze (>95%), which can create a uniform and consistent daylight distribution over the day without glare effect; (3) unique light guiding effect with a large forward to back scattering ratio of 9 for a 0.5 cm thick transparent wood; (4) excellent thermal insulation with a thermal conductivity around 0.32 W m−1 K−1 along the wood growth direction and 0.15 W m−1 K−1 in the cross plane, much lower than that of glass (≈1 W m−1 K−1); (5) high impact energy absorption that eliminates the safety issues often presented by glass; and (6) simple, scalable fabrication with reliable performance. The demonstrated transparent wood composite exhibits great promise as a future building material, especially as a replacement of glass toward energy efficient building with sustainable materials.
Some features of scattering problem in a κ‐Deformed minkowski spacetime
Authors: Khodadi M. , Nozari K.
Published: August 2016

The doubly special relativity (DSR) theories are suggested in order to incorporate an observer‐independent length scale in special theory of relativity. The Magueijo‐Smolin proposal of DSR is realizable through a particular form of the noncommutative (NC) spacetime (known as κ‐Minkowski spacetime) in which the Lorentz symmetry is preserved. In this framework, the NC parameter κ provides the origin of natural cutoff energy scale. Using a nonlinear deformed relativistic dispersion relation along with the Lorentz transformations, we investigate some phenomenological facets of two‐body collision problem (without creation of new particles) in a κ‐Minkowski spacetime. By treating an elastic scattering problem, we study effects of the Planck scale energy cutoff on some relativistic kinematical properties of this scattering problem. The results are challenging in the sense that as soon as one turns on the κ‐spacetime extension, the nature of the two‐body collision alters from elastic to inelastic one. It is shown also that a significant kinematical variable involving in heavy ion collisions, the rapidity, is not essentially an additive quantity under a sequence of the nonlinear representation of the Lorentz transformations.

image
Maßgeschneiderte Aufwärtskonvertierungsnanopartikel zur Detektion von Proteinwechselwirkungen in lebenden Zellen
Authors: Drees Christoph , Raj Athira Naduviledathu , Kurre Rainer , Busch Karin B. , Haase Markus , Piehler Jacob
Published: August 2016

Nanopartikel mit der Fähigkeit zur Aufwärtskonvertierung (“upconversion nanoparticles”, UCNP) wandeln nahinfrarotes in sichtbares Licht bei wesentlich geringeren Anregungsleistungsdichten als in klassischer Zweiphotonenmikroskopie um. In dieser Studie haben wir <50 nm UCNP für die Anwendung als effiziente Lanthanoid‐basierte Donoren für den Resonanzenergietransfer (LRET) in lebenden Zellen entwickelt. Durch die Optimierung der Dotierung und Kern‐Schale‐Struktur für höhere Anregungsdichten konnten wir nicht nur verstärkte UCNP‐Emission, sondern auch massiv erhöhte sensibilisierte Akzeptorfluoreszenz beobachten. Für die Applikation von UCNP in komplexer biologischer Umgebung haben wir eine biokompatible Oberflächenfunktionalisierung mit einem Nanobody, der Grün fluoreszierendes Protein (GFP) erkennt, entwickelt. Hierdurch wurde die schnelle und spezifische Bindung an GFP‐markierte Fusionsproteine in der äußeren Mitochondrienmembran sowie die Detektion von Proteininteraktionen mittels LRET erreicht.
Modifizierung der 5′‐Kappe eukaryotischer mRNA für Klick‐Reaktionen und zur Beeinflussung der Translationseffizienz in lebenden Zellen
Authors: Holstein Josephin M. , Anhäuser Lea , Rentmeister Andrea
Published: August 2016

Die 5′‐Kappe ist ein Charakteristikum eukaryotischer mRNAs und nimmt im RNA‐Metabolismus entscheidende Rollen ein, die sich von der Qualitätskontrolle über den Export bis hin zur Translation erstrecken. Die Modifizierung der 5′‐Kappe könnte daher die Modulierung dieser Prozesse und die Erforschung verschiedener biologischer Funktionen ermöglichen. Wir präsentieren einen direkten Ansatz zur Erzeugung einer Auswahl N7‐modifizierter Kappen basierend auf der hoch promiskuitiven Methyltransferase Ecm1. Wir zeigen, dass diese sowie N2‐modifizierte 5′‐Kappen zur Steuerung der Translation entsprechender mRNAs in vitro und in Zellen genutzt werden können. Entsprechende Modifikationen ermöglichen die anschließende Anwendung bioorthogonaler Reaktionen, z. B. die intrazelluläre Markierung einer Ziel‐mRNA in lebenden Zellen. Die effiziente und vielseitige Manipulierung des N7‐Atoms der mRNA‐Kappe ist ein wertvoller Beitrag zum Methodenrepertoire der chemischen Biologie.
Monodisperse Cylindrical Micelles of Controlled Length with a Liquid‐Crystalline Perfluorinated Core by 1D “Self‐Seeding”
Authors: Li Xiaoyu , Jin Bixin , Gao Yang , Hayward Dominic W. , Winnik Mitchell A. , Luo Yunjun , Manners Ian
Published: August 2016

Precise control over the morphology and dimensions of block copolymer (BCP) micelles has attracted interest due to the potential of this approach to generate functional nanostructures. Incorporation of liquid crystalline (LC) block can provide additional ways to vary micellar morphologies, but the formation of uniform micelles with controllable dimensions from LC BCPs has not yet been realized. Herein, we report the preparation of monodisperse cylindrical micelles with a LC poly(2‐(perfluorooctyl)ethyl methacrylate (PFMA) core via a fragmentation‐thermal annealing (F‐TA) process, resembling the “self‐seeding” process of crystalline BCP micelles. The average length of the cylinders increases with annealing temperature, with a narrow length distribution (Lw/Ln<1.1). We also demonstrate the potential application of the cylinders with LC cores as a cargo‐carrier by the successful incorporation of a hydrophobic fluorescent dye tagged with a fluorooctyl group.
Concerted Rattling in CsAg5Te3 Leading to Ultralow Thermal Conductivity and High Thermoelectric Performance
Authors: Lin Hua , Tan Gangjian , Shen Jin‐Ni , Hao Shiqiang , Wu Li‐Ming , Calta Nicholas , Malliakas Christos , Wang Si , Uher Ctirad , Wolverton Christopher , Kanatzidis Mercouri G.
Published: August 2016

Thermoelectric (TE) materials convert heat energy directly into electricity, and introducing new materials with high conversion efficiency is a great challenge because of the rare combination of interdependent electrical and thermal transport properties required to be present in a single material. The TE efficiency is defined by the figure of merit ZT=(S2σ) T/κ, where S is the Seebeck coefficient, σ is the electrical conductivity, κ is the total thermal conductivity, and T is the absolute temperature. A new p‐type thermoelectric material, CsAg5Te3, is presented that exhibits ultralow lattice thermal conductivity (ca. 0.18 Wm−1 K−1) and a high figure of merit of about 1.5 at 727 K. The lattice thermal conductivity is the lowest among state‐of‐the‐art thermoelectrics; it is attributed to a previously unrecognized phonon scattering mechanism that involves the concerted rattling of a group of Ag ions that strongly raises the Grüneisen parameters of the material.
Gold lässt Fibrillen wachsen: der Mechanismus der oberflächenunterstützten Amyloid‐Aggregation
Authors: Gladytz Anika , Abel Bernd , Risselada Herre Jelger
Published: August 2016

Die Frage, wie Amyloidfibrillenbildung von Oberflächen beeinflusst wird, ist entscheidend für das Verständnis des Prozesses in vivo. Wir haben eine Kombination von kinetischen Experimenten und Moleküldynamiksimulationen angewendet, um aufzuklären, wie (Modell‐)Oberflächen die Fibrillenbildung der amyloidbildenden Sequenzen des Prionenproteins SUP35 und des Insel‐Amyloid‐Polypeptids beeinflussen. Kinetische Daten legen nahe, dass eine Restrukturierung der initialen Peptidkorona um die kolloidalen Goldnanopartikel der zeitlimitierende Schritt ist. Moleküldynamiksimulationen zeigen, dass partielle Physisorption an der Oberfläche zur Bildung von geordneten Monolagen führt, die die Bildung von parallelen, kritischen Oligomeren stimuliert. Der generelle Mechanismus beinhaltet, dass die zugrundeliegende Peptid‐Peptid‐ und die Peptid‐Oberflächen‐Wechselwirkung in der gleichen Größenordnung liegen müssen, um die Fibrillenbildung zu beschleunigen.
tRNA Shifts the G‐quadruplex–Hairpin Conformational Equilibrium in RNA towards the Hairpin Conformer
Authors: Rode Ambadas B. , Endoh Tamaki , Sugimoto Naoki
Published: August 2016

Non‐coding RNAs play important roles in cellular homeostasis and are involved in many human diseases including cancer. Intermolecular RNA–RNA interactions are the basis for the diverse functions of many non‐coding RNAs. Herein, we show how the presence of tRNA influences the equilibrium between hairpin and G‐quadruplex conformations in the 5′ untranslated regions of oncogenes and model sequences. Kinetic and equilibrium analyses of the hairpin to G‐quadruplex conformational transition of purified RNA as well as during co‐transcriptional folding indicate that tRNA significantly shifts the equilibrium toward the hairpin conformer. The enhancement of relative translation efficiency in a reporter gene assay is shown to be due to the tRNA‐mediated shift in hairpin‐G‐quadruplex equilibrium of oncogenic mRNAs. Our findings suggest that tRNA is a possible therapeutic target in diseases in which RNA conformational equilibria is dysregulated.
Lanthanide‐Catalyzed Reversible Alkynyl Exchange by Carbon–Carbon Single‐Bond Cleavage Assisted by a Secondary Amino Group
Authors: Shao Yinlin , Zhang Fangjun , Zhang Jie , Zhou Xigeng
Published: August 2016

Lanthanide‐catalyzed alkynyl exchange through C−C single‐bond cleavage assisted by a secondary amino group is reported. A lanthanide amido complex is proposed as a key intermediate, which undergoes unprecedented reversible β‐alkynyl elimination followed by alkynyl exchange and imine reinsertion. The in situ homo‐ and cross‐dimerization of the liberated alkyne can serve as an additional driving force to shift the metathesis equilibrium to completion. This reaction is formally complementary to conventional alkyne metathesis and allows the selective transformation of internal propargylamines into those bearing different substituents on the alkyne terminus in moderate to excellent yields under operationally simple reaction conditions.
Mercury Methylation by Cobalt Corrinoids: Relativistic Effects Dictate the Reaction Mechanism
Authors: Demissie Taye B. , Garabato Brady D. , Ruud Kenneth , Kozlowski Pawel M.
Published: August 2016

The methylation of HgII(SCH3)2 by corrinoid‐based methyl donors proceeds in a concerted manner through a single transition state by transfer of a methyl radical, in contrast to previously proposed reaction mechanisms. This reaction mechanism is a consequence of relativistic effects that lower the energies of the mercury 6p1/2 and 6p3/2 orbitals, making them energetically accessible for chemical bonding. In the absence of spin–orbit coupling, the predicted reaction mechanism is qualitatively different. This is the first example of relativity being decisive for the nature of an observed enzymatic reaction mechanism.
Rapid Identification of the Receptor‐Binding Specificity of Influenza A Viruses by Fluorogenic Glycofoldamers
Authors: He Xiao‐Peng , Zeng Ya‐Li , Tang Xin‐Ying , Li Na , Zhou Dong‐Ming , Chen Guo‐Rong , Tian He
Published: August 2016

The re‐emergence of influenza raises a global concern that viral pandemics can unpredictably occur. However, effective approaches that can probe the infection risk of influenza viruses for humans are rare. In this work, we develop a glycofoldamer that can rapidly identify the glycan‐receptor specificity of influenza viruses in a high‐throughput manner. The coupling of glycan receptors that can be recognized by hemagglutinin (a surface protein on the virion capsid of influenza) to a fluorogenic‐dye foldamer produces the glycofoldamers with minimal fluorescence in aqueous solution. After interaction with human‐infecting virus strains for only five minutes, the fluorescence intensity of the glycofoldamer is remarkably enhanced with a blue‐shifted emission peak. The probes have also proven effective for the rapid identification of 1) the human‐ or bird‐infecting properties of influenza viruses in a high‐throughput manner and 2) the receptor‐specificity switch of a virus strain by mutations.
Engineered Upconversion Nanoparticles for Resolving Protein Interactions inside Living Cells
Authors: Drees Christoph , Raj Athira Naduviledathu , Kurre Rainer , Busch Karin B. , Haase Markus , Piehler Jacob
Published: August 2016

Upconversion nanoparticles (UCNPs) convert near‐infrared into visible light at much lower excitation densities than those used in classic two‐photon absorption microscopy. Here, we engineered <50 nm UCNPs for application as efficient lanthanide resonance energy transfer (LRET) donors inside living cells. By optimizing the dopant concentrations and the core–shell structure for higher excitation densities, we observed enhanced UCNP emission as well as strongly increased sensitized acceptor fluorescence. For the application of these UCNPs in complex biological environments, we developed a biocompatible surface coating functionalized with a nanobody recognizing green fluorescent protein (GFP). Thus, rapid and specific targeting to GFP‐tagged fusion proteins in the mitochondrial outer membrane and detection of protein interactions by LRET in living cells was achieved.
The Planar Blatter Radical: Structural Chemistry of 1,4‐Dihydrobenzo[e][1,2,4]triazin‐4‐yls
Authors: Kaszyński Piotr , Constantinides Christos P. , Young Victor G.
Published: August 2016

Two planarized analogues of the prototypical Blatter radical (1), peri‐annulated 1S and 1O, are demonstrated and provide a new platform for molecular and supramolecular engineering, and for tuning electronic and magnetic properties of the radical. Planarization of 1 results in bathochromic shift to the near‐IR region, greater spin delocalization, and anodic shift of the reduction potential only for 1S. Magnetization studies revealed nearly ideal paramagnetic behavior at high temperatures for both radicals 1S and 1O with one‐dimensional ferromagnetic interaction in the former (2J=14.4 cm−1) and antiferromagnetic interactions in 1O at low temperatures.
Diverse Reactivity of an Electrophilic Phosphasilene towards Anionic Nucleophiles: Substitution or Metal–Amino Exchange
Authors: Willmes Philipp , Junk Lukas , Huch Volker , Yildiz Cem B. , Scheschkewitz David
Published: August 2016

The reaction of MesLi (Mes=2,4,6‐trimethylphenyl) with the electrophilic phosphasilene R2(NMe2)Si‐RSi=PNMe2(2, R=Tip=2,4,6‐triisopropylphenyl) cleanly affords R2(NMe2)Si‐RSi=PMes and thus provides the first example of a substitution reaction at an unperturbed Si=P bond. In toluene, the reaction of2with lithium disilenide, R2Si=Si(R)Li (1), apparently proceeds via an initial nucleophilic substitution step as well (as suggested by DFT calculations), but affords a saturated bicyclo[1.1.0]butane analogue as the final product, which was further characterized as its Fe(CO)4complex. In contrast, in 1,2‐dimethoxyethane the reaction of1with2results in an unprecedented metal–amino exchange reaction.
Efficient Room‐Temperature Activation of Methane by TaN+ under C−N Coupling
Authors: Zhou Shaodong , Li Jilai , Schlangen Maria , Schwarz Helmut
Published: August 2016

The thermal reaction of diatomic tantalum nitride cation [TaN]+ with methane has been explored using FT‐ICR mass spectrometry complemented by high‐level quantum chemical calculation; based on this combined experimental/computational approach, mechanistic aspects of this novel, highly efficient C−N coupling process have been uncovered. In distinct contrast to [TaN]+, its lighter congeners [VN]+ and [NbN]+ are inert towards methane under ambient conditions, and the origins of the remarkably variable efficiencies of the three metal nitrides are uncovered by CCSD(T) calculations.
Multiporous microstructure for enhancing the water absorption and swelling rate in poly(sodium acrylic acid) superabsorbent hydrogels based on a novel physical and chemical composite foaming system
Authors: Chen Si , Zhou Bo , Ma Meng , Wu Bozhen , Shi Yanqin , Wang Xu
Published: August 2016

In this article, we report a novel physical and chemical composite foaming system, which was used to successfully prepare high‐performance and low‐cost composite superabsorbent [poly(sodium acrylic acid) (PAA–Na)] hydrogels based on acrylic acid by free‐radical polymerization in a water bath under a nitrogen atmosphere without the use of any organic solvents. The prepared hydrogels showed superabsorbent properties, high water‐absorption abilities and swelling rates, a lighter packing density, and a multiporous microstructure. Fourier transform infrared spectroscopy and scanning electron microscopy revealed that the sodium dodecyl sulfate surfactant, sodium bicarbonate chemical foaming agent, and 1,1,2‐trifluorotrichloroethane physical foaming agent were evenly distributed and grafted onto the PAA–Na matrix. Water‐absorption, swelling rate, and packing density testing confirmed that the superabsorbent had a high water‐absorption ability and swelling rate and a lighter packing density. Furthermore, we investigated the effects of different foaming agents, including chemical and physical foaming agents, on the swelling and water‐retention capabilities of the superabsorbent hydrogels (SAHs).The results show that the combination of these foaming agents significantly improved the water‐absorbing capacity. With the help of these foaming agents, we obtained PAA–Na hydrogels without any organic solvents for posttreatment or special porogens; this is an environmentally beneficial way to prepare SAHs for hygiene and biomedical products. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44149.
Polyurethane foams from oligomers derived from waste tire crumbs and polycaprolactone diols
Authors: Rattanapan Suwat , Pasetto Pamela , Pilard Jean‐François , Tanrattanakul Varaporn
Published: August 2016

This work was an initial study on the synthesis of polyurethane foams (PUF) by using diols obtained from the controlled degradation of waste tire crumbs and from polycaprolactone (PCL) followed by examination of their biodegradability. Natural rubber (NR, cis−1,4 polyisoprene) and butadiene rubber (BR) chains contained in waste tire crumbs were chemically modified into carbonyl telechelic (CTWT) and successively into hydroxyl telechelic oligomers (HTWT). Four types of PUF were prepared with different molar ratios between the HTWT and the PCL diols. CTWT and HTWT were analyzed by 1H‐NMR, SEC, and FT‐IR to confirm their chemical structure. Formation of the urethane bond was demonstrated by FT‐IR spectra. The addition of the PCL diol increased the thermal degradation temperature of the PUF based on thermogravimetric analysis. According to scanning electron microscopy, polyhedral closed cells were obtained. The molar ratio of HTWT/PCL diols strongly affected the kinetic rate of foam formation and foam morphology. A low kinetic rate provided PUF with a high density, small cell size, and a broad cell size distribution. In order to assess biodegradation of PUF, the modified Sturm test was carried out for 60 days at ambient temperature (27–30 °C). The biodegradation of PUF containing only HTWT was 31.2% and 51.3% at 28 days and 60 days of testing, respectively whereas the PUF containing 1/0.5 HTWT/PCL diols (by mole) showed a higher biodegradation: 39.1% and 64.3% at 28 days and 60 days of testing respectively. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44251.
A Novel Trihybrid Material Based on Renewables: An Efficient Recyclable Heterogeneous Catalyst for C−C Coupling and Reduction Reactions
Authors: Majumdar Rakhi , Tantayanon Supawan , Gopal Bag Braja
Published: August 2016

The generation of organic–inorganic hybrid materials from renewable resources and their utilization in basic and applied areas has been at the forefront of research in recent years for sustainable development. Herein, a novel organic–inorganic trihybrid material was synthesized by in situ generation of palladium nanoparticles (PdNPs) in a hybrid gel matrix based on renewable chemicals. Constituents of the hybrid gel included a pentacyclic triterpenoid arjunolic acid extractable from Terminalia arjuna and the leaf extract of Chrysophyllum cainito rich in flavonoids. We took advantage of the presence of flavonoid molecules in this hybrid gel to generate an advanced trihybrid gel through in situ reduction of doped PdII salts to stable PdNPs. The xerogel of this trihybrid material was used as a recyclable heterogeneous catalyst for C−C coupling and reduction reactions in aqueous media. We also demonstrated that the in situ generated PdNPs containing trihybrid material was a more efficient catalyst than the trihybrid material generated with presynthesized PdNPs.
Holzbrücken – Erkenntnisse zum Feuchteverhalten in den Tragquerschnitten aus Langzeitmessungen
Authors: Franke Bettina , Müller Andreas , Simon Antje
Published: August 2016

Die Leistungsfähigkeit von Holz im Brückenbau ist durch zahlreiche Konstruktionen weltweit belegt. Gegenüber Holz sind aktuell noch Hemmnisse bei den Straßenbaubehörden und Planern vorhanden, die die Anzahl der Projekte beschränken. Die infolge des variierenden Klimas respektive der Holzfeuchteänderung resultierenden Eigenspannungen im Querschnitt wurden bisher vorwiegend unter Laborbedingungen untersucht. Die Untersuchungen ergaben, dass die Holzfeuchte sich über den Querschnitt unterschiedlich stark ändert, was zu internen Spannungen führt. Die Diskussion über zuverlässige Ansätze für die Beurteilung der sich ausbildenden Eigenspannungen in Brückenquerschnitten ist stetig. Erste Empfehlungen liefern die gewonnenen Erkenntnisse zum Feuchteverhalten aus sieben über mehrere Jahre überwachten Straßenbrücken. In allen Konstruktionen wurde der Holzfeuchtegehalt in Beziehung zum vorherrschenden lokalen Klima erfasst. Die Einflüsse aus dem lokalen Klima sind nicht zu vernachlässigen. Positiv ist, dass die gemessenen Holzfeuchten geringer sind als die aus den Daten der nahe liegenden Wetterstation resultierende Ausgleichsfeuchte. Die Auswertung der Feuchtegradienten im Querschnitt lässt eine Abgrenzung zwischen einer ruhigen und beanspruchten Querschnittszone erkennen.
Race for Power in Public Good Games with Unequal, Unstable Punishment Power
Authors: Dorrough Angela , Glöckner Andreas , Lee Borah
Published: August 2016

Decentralized punishment can maintain contributions to a public good at a high level. This positive effect holds even for situations involving inequality in punishment power, meaning that the relative costs for punishment differ between persons. We extend this line of research by examining the additional influence of instability of and thus potential competition for punishment power in public good experiments. As in previous research, inequality is operationalized by assigning the role of a ‘strong player’ to one group member, who can punish others at a reduced cost compared to other players. Instability is operationalized by the fact that the role assignment can change across rounds and is contingent on behavior in previous rounds. Three experiments show that under unequal, unstable (punishment‐) power, individuals behave more competitively and engage in arace for powerresulting in detrimental effects for the group. Specifically, we find that (i) unstable power goes along with a disproportionate use of punishment; (ii) not inequality by itself but rather the combination of instability and inequality causes this effect; and (iii) this excessive use of punishment is found not only when the role of the strong player is assigned to individuals who previously behaved rather selfishly but also when prosocial behavior leads to the top, speaking for a generalizability of our findings. Implications for organizational settings are discussed. Copyright © 2016 John Wiley & Sons, Ltd.
Congenital abnormalities in newborns of women with pregestational diabetes: A time‐trend analysis, 1994 to 2009
Authors: Agha Mohammad M. , Glazier Richard H. , Moineddin Rahim , Booth Gillian
Published: August 2016

Background

The main objective of the current study is to examine the trend of congenital abnormalities among children born by women with and without diabetes, and to explore the impact of food fortification by folic acid on the rate of birth defects among these two groups of mothers.

Methods

All children born alive in Ontario, Canada, during 1994 to 2009 and their mothers were included in study. Diagnosis of pregestational diabetes among mothers was identified using Diabetes registry, and diagnosis of birth defects among children were identified using hospital records.

Results

The prevalence of births among diabetic mothers increased by almost 200% during the study period. Among children born to mothers with diabetes, the prevalence for all anomalies combined was approximately 47% higher and for various cardiac and central nervous system anomalies up to a three‐ to fivefold higher than those born to nondiabetic mothers. While the rate of birth defects in both groups observed a considerable decline after food fortification in 1999, but the gap between two groups remained unchanged over time.

Conclusion

While the prevalence of birth defects among diabetic pregnancies is still considerably higher that nondiabetic pregnancies, results of the current study indicate a declining trend in the prevalence of some congenital abnormalities among babies born to both diabetic and nondiabetic mothers after 1999. We need to be more aggressive in implementing preventive measures, including a national diabetes plan or the proposed universal policy of supra‐dietary folic acid supplementation for women with diabetes who are of reproductive age. Birth Defects Research (Part A) 106:831–839, 2016. © 2016 Wiley Periodicals, Inc.
Conflicts over host manipulation between different parasites and pathogens: Investigating the ecological and medical consequences
Authors: Hafer Nina
Published: August 2016

When parasites have different interests in regard to how their host should behave this can result in a conflict over host manipulation, i.e. parasite induced changes in host behaviour that enhance parasite fitness. Such a conflict can result in the alteration, or even complete suppression, of one parasite's host manipulation. Many parasites, and probably also symbionts and commensals, have the ability to manipulate the behaviour of their host. Non‐manipulating parasites should also have an interest in host behaviour. Given the frequency of multiple parasite infections in nature, potential conflicts of interest over host behaviour and manipulation may be common. This review summarizes the evidence on how parasites can alter other parasite's host manipulation. Host manipulation can have important ecological and medical consequences. I speculate on how a conflict over host manipulation could alter these consequences and potentially offer a new avenue of research to ameliorate harmful consequences of host manipulation.
Aqueous synthesis of highly stable CdTe/ZnS Core/Shell quantum dots for bioimaging
Authors: Saikia D. , Chakravarty S. , Sarma N. S. , Bhattacharjee S. , Datta P. , Adhikary N. C.
Published: August 2016

In this work, we report the synthesis, characterization and biological application of highly stable CdTe/ZnS (cadmium tellurite/zinc sulphide) Core/Shell (CS) quantum dots (QDs) capped with mercaptosuccinic acid (MSA). The CS QDs were synthesized using a simple one‐pot aqueous method. The synthesized CdTe/ZnS CS QDs were found to exhibit excellent stability even 100 days after preparation and also showed better photoluminescence quantum yield (PLQY) of about 50% compared with that of only CdTe QDs which was nearly 12%. The formation of the CdTe/ZnS CS was confirmed by high‐resolution transmission electron microscopy (HR‐TEM), and Fourier transform infra‐red (FTIR) and X‐ray diffraction (XRD) analyses. Further, on extending our study towards bioimaging of E. coli cells using the QDs samples, we found that CdTe/ZnS CS QDs showed better results compared with CdTe QDs.
Radiofrequency ablation compared with laparoscopic adrenalectomy for aldosterone-producing adenoma
Authors: Liu S Y , Chu C M , Kong A P , Wong S K , Chiu P W , Chow F C , Ng E K
Published: August 2016

Background

Radiofrequency ablation (RFA) is an emerging treatment for primary aldosteronism owing to aldosterone-producing adenoma. Whether RFA could be an alternative treatment to laparoscopic adrenalectomy is unknown.

Methods

This was a retrospective comparative study in patients with aldosterone-producing adenoma undergoing either laparoscopic adrenalectomy or CT-guided percutaneous RFA between 2004 and 2012. Short-term outcomes and long-term resolution rates of primary aldosteronism (normalized aldosterone to renin ratio), hypokalaemia and hypertension (BP lower than 140/90 mmHg without antihypertensive medical therapy) were evaluated.

Results

Some 63 patients were included, 27 in the laparoscopic adrenalectomy group and 36 in the RFA group. RFA was associated with shorter duration of operation (median 12 versus 124 min; P < 0·001), shorter hospital stay (2 versus 4 days; P < 0·001), lower analgesic requirements (13 of 36 versus 23 of 27 patients; P < 0·001) and earlier resumption of work (median 4 versus 14 days; P = 0·006). Morbidity rates were similar in the two groups. With median follow-up of 5·7 (range 1·9–10·6) years, resolution of primary aldosteronism was seen in 33 of 36 patients treated with RFA and all 27 patients who had laparoscopic adrenalectomy (P = 0·180). Hypertension was resolved less frequently after treatment with RFA compared with laparoscopic adrenalectomy (13 of 36 versus 19 of 27 patients; P = 0·007). Hypokalaemia was resolved in all patients.

Conclusion

For patients with aldosterone-producing adenoma the efficacy of resolution of primary aldosteronism and hypertension was inferior after treatment with RFA compared with laparoscopic adrenalectomy.
Application of Cookson‐type reagents for biomedical HPLC and LC/MS analyses: a brief overview
Authors: Higashi Tatsuya , Shimada Kazutake
Published: August 2016

High‐performance liquid chromatography (HPLC), LC/mass spectrometry (MS) and LC/tandem mass spectrometry (MS/MS) have been widely used for biomedical analyses, in which chemical derivatization is one of the most important methods to increase the sensitivity and selectivity. A Cookson‐type reagent [4‐substituted‐1,2,4‐triazoline‐3,5‐dione (4‐substituted‐TAD)] reacts with the compound bearing a conjugated diene, such as the vitamin D compound, to quantitatively form the stable Diels–Alder adduct. The reagent with a chromophore or fluorophore at the 4‐position of TAD yields a highly responsive adduct for the UV or fluorescence detection, respectively. The Diels–Alder adduct with a Cookson‐type reagent having a permanently charged, proton‐affinitive or electron‐affinitive moiety is sensitively detected by a specific MS analyzer. This paper is a brief overview of the applications of the reagents for biomedical analyses mainly using HPLC or LC/MS(/MS).
A Cobalt‐Based Film for Highly Efficient Electrocatalytic Water Oxidation in Neutral Aqueous Solution
Authors: Chen Hu , Gao Yan , Sun Licheng
Published: August 2016

A cobalt‐based film (Co‐Hi) for water oxidation was prepared in 2‐[4‐(2‐hydroxyethyl)piperazin‐1‐yl]ethanesulfonic acid buffer at pH 7.0 through a unique cyclic voltammetry electrodeposition method by applying a wide scan range from 1.40 to −1.00 V versus normal hydrogen electrode (NHE). This catalyst film displayed highly efficient activity during oxygen evolution in neutral aqueous solution. An impressive current density of more than 1.5 mA cm−2 that was stable over a prolonged time period was obtained with a remarkably low onset overpotential of 230 mV in 0.1 m phosphate buffer (pH 7.0).