bluuebunny/crossref_metadata_2025 huggingface dataset:
Derivation and use of core surface flows for forecasting secular variation
Authors: Whaler K. A. , Beggan C. D.
Published: February 2015

Improving forecasts of the temporal and spatial changes of the Earth's main magnetic field over periods of less than 5 years has important scientific and economic benefits. Various methods for forecasting the rate of change, or secular variation, have been tried over the past few decades, ranging from the extrapolation of trends in ground observatory measurements to computational geodynamo modeling with data assimilation from historical magnetic field models. We examine the utility of an intermediate approach, using temporally varying core surface flow models derived from relatively short periods of magnetic field data to produce, by advection, secular variation estimates valid for the Earth's surface. We describe a new method to compute a core flow changing linearly with time from magnetic secular variation and acceleration data. We invert a combination of data from the CHAMP satellite mission and ground observatories over the period 2001.0 to 2010.0 for a series of such models. We assess their ability to forecast magnetic field changes by comparing them to CHAOS‐4, a state‐of‐the‐art model using data from 1997 to 2014.5. We show that the magnetic field predictions tend to have a lower root‐mean‐square difference from CHAOS‐4 than the International Geomagnetic Reference Field or World Magnetic Map series of secular variation models.
An analysis of the evolution of Meddies in the North Atlantic using floats and multisensor satellite data
Authors: Jo Young‐Heon , Ienna Federico , Yan Xiao‐Hai
Published: February 2015

Previous studies focusing on the remote detection of Mediterranean Eddies (Meddies) have reported that the isopycnal surface changes derived from satellite multisensor measurements at the approximate depth of 400 m can be used to sense the presence of underlying Meddies. While the isopycnal surface near that depth does indeed reveal the locations of Meddies, an analysis of isopycnal surface changes in response to the evolution of Meddies has yet to be made. Accordingly, this research focuses on analyzing the relationship between isopycnal surface changes and the evolution of Meddies. The vertical isopycnal surface variability of Meddies, which is directly related to contributions from rotational velocity, interior thermal variation, and vertical displacement of Meddies, is observed and studied using float observations from A Mediterranean Undercurrent Seeding Experiment (AMUSE). The contributions of each of the three aforementioned parameters are estimated, enabling us to understand their relative role in changing the isopycnal surface above Meddies. Furthermore, in order to further understand Meddies' evolution and their associated forcing, the dominant frequencies of their horizontal and vertical displacements, as well as the sea surface height variability above the Meddy, are analyzed using the Hilbert‐Huang Transform. Finally, the horizontal and the vertical eddy viscosity dissipation of Meddies is computed and compared with a theoretical model. The empirical horizontal and the vertical eddy viscosities are found to be 7 × 106 cm2 s−1 and 200 cm2 s−1, respectively. This study will therefore contribute to understanding how the isopycnal surface is related to the presence of Meddies, what frequencies dominate its variability, and the values of eddy viscosity which can be used for a numerical model.
Three‐dimensional structures of tropical nonmigrating tides in a high‐vertical‐resolution general circulation model
Authors: Sakazaki Takatoshi , Sato Kaoru , Kawatani Yoshio , Watanabe Shingo
Published: February 2015

This paper investigates nonmigrating tides from the ground to the lower mesosphere using data from a high‐resolution general circulation model (KANTO GCM), as well as observational data from the Sounding of the Atmosphere using Broadband Emission Radiometry instrument on board the Thermosphere‐Ionosphere‐Mesosphere Energetics and Dynamics satellite and from GPS radio occultation measurements obtained with the COSMIC/FORMOSAT‐3 mission. We extract nonmigrating tides using a composite as a function of universal time in physical space, without performing a zonal wave number decomposition. The KANTO GCM clearly demonstrates that tropical nonmigrating tides are regarded as gravity waves excited by diabatic heating enhanced over two major continents, specifically Africa and South America. They propagate zonally, in a direction away from their sources; that is, west and eastward propagating waves are dominant on the western and eastern sides of the continents, respectively. These characteristics are observed in two satellite data sets as well, except that the amplitudes in the KANTO GCM are larger than those in the observations. Seasonal variations of nonmigrating tides are also investigated. It is suggested that filtering owing to the stratopause semiannual oscillation, as well as diabatic heating in the troposphere, is important for the seasonal variations of nonmigrating tides in the stratosphere and the lower mesosphere.
Multiple regression and inverse moments improve the characterization of the spatial scaling behavior of daily streamflows in the Southeast United States
Authors: Farmer William H. , Over Thomas M. , Vogel Richard M.
Published: February 2015

Understanding the spatial structure of daily streamflow is essential for managing freshwater resources, especially in poorly gaged regions. Spatial scaling assumptions are common in flood frequency prediction (e.g., index‐flood method) and the prediction of continuous streamflow at ungaged sites (e.g. drainage‐area ratio), with simple scaling by drainage area being the most common assumption. In this study, scaling analyses of daily streamflow from 173 streamgages in the southeastern United States resulted in three important findings. First, the use of only positive integer moment orders, as has been done in most previous studies, captures only the probabilistic and spatial scaling behavior of flows above an exceedance probability near the median; negative moment orders (inverse moments) are needed for lower streamflows. Second, assessing scaling by using drainage area alone is shown to result in a high degree of omitted‐variable bias, masking the true spatial scaling behavior. Multiple regression is shown to mitigate this bias, controlling for regional heterogeneity of basin attributes, especially those correlated with drainage area. Previous univariate scaling analyses have neglected the scaling of low‐flow events and may have produced biased estimates of the spatial scaling exponent. Third, the multiple regression results show that mean flows scale with an exponent of one, low flows scale with spatial scaling exponents greater than one, and high flows scale with exponents less than one. The relationship between scaling exponents and exceedance probabilities may be a fundamental signature of regional streamflow. This signature may improve our understanding of the physical processes generating streamflow at different exceedance probabilities.
A robust fixed‐lag receding horizon smoother for uncertain state space models
Authors: Kwon Bokyu , Quan Zhonghua , Han Soohee
Published: February 2015

In this paper, a robust fixed‐lag receding horizon (RH) smoother is proposed for a discrete‐time state space model with bounded uncertainties. The proposed robust RH smoother is based on a set‐valued state estimation method, which produces a set of possible estimates based on inputs and outputs measured over a finite time horizon. The set of possible estimates is represented in an ellipsoidal form, and then the major axis of the ellipsoid is minimized with respect to the preview size. The center of the ellipsoid with the minimum major axis is taken as the estimate of the real state to minimize the possible maximum estimation error under bounded uncertainties. It is illustrated through a numerical example that the proposed robust RH smoother has better performance than the conventional robust Kalman smoothers. Copyright © 2015 John Wiley & Sons, Ltd.
In Situ Synthesis of (TiC + Ti3SiC2 + Ti5Si3)/Ti6Al4V Composites with Tailored Two‐scale Architecture
Authors: Liu C. , Huang L. J. , Geng L. , Jiao Y. , Tang A.
Published: February 2015

In situ TiC particle, Ti3SiC2 bar and ultrafine Ti5Si3 needle reinforced Ti6Al4V ((TiC+Ti3SiC2+Ti5Si3)/Ti6Al4V) composites with a tailored distribution were sucessfully designed and fabricated. The first‐scale tailored architecture of reinforcement is the in situ synthesized Ti3SiC2 bars and near‐equiaxed TiC particles on the network boundary around Ti6Al4V particles. The secondary‐scale architecture is the ultrafine Ti5Si3 needles precipitated in intergranular β phase of center Ti6Al4V matrix particle. The results showed that the two‐scale tailored architecture of different reinforcements can significantly improve strength remained with moderate ductility of the composites.
Localized Laser‐Based Photohydrothermal Synthesis of Functionalized Metal‐Oxides
Authors: Kwon Kyungmook , Shim Jaeho , Lee Jeong Oen , Choi Kyunghan , Yu Kyoungsik
Published: February 2015

We discuss the rapid in situ hydrothermal synthesis of metal oxide materials based on the photothermal superheating of light‐absorbing metal layers for simple and facile on‐demand placement of semiconductor materials with micrometer‐scale lateral resolution. Localized heating from pulsed and focused laser illumination enables ultrafast growth of metal oxide materials with high spatiotemporal precision in aqueous precursor solution. Among many possible electronic and optoelectronic applications, the proposed method can be used for laser‐based in situ real‐time soldering of separated metal structures and electrodes with functionalized semiconductor materials. Resistive electrical interconnections of metal strip lines as well as sensitive UV detection using photohydrothermally grown metal oxide bumps are experimentally demonstrated.
Under‐Water Superaerophobic Pine‐Shaped Pt Nanoarray Electrode for Ultrahigh‐Performance Hydrogen Evolution
Authors: Li Yingjie , Zhang Haichuan , Xu Tianhao , Lu Zhiyi , Wu Xiaochao , Wan Pengbo , Sun Xiaoming , Jiang Lei
Published: February 2015

A pine‐shaped Pt nanostructured electrode with under‐water superaerophobicity for ultrahigh and steady hydrogen evolution reaction (HER) performance is successfully fabricated by a facile and easily scalable electrodeposition technique. Due to the lower bubble adhesive force (11.5 ± 1.2 μN), the higher bubble contact angle (161.3° ± 3.4°) in aqueous solution, and the smaller size of bubbles release for pine‐shaped Pt nanostructured electrode, the incomparable under‐water superaerophobicity for final repellence of bubbles from submerged surface with ease, is successfully achieved, compared to that for nanosphere electrode and for Pt flat electrode. With the merits of superior under‐water superaerophobicity and excellent nanoarray morphology, pine‐shaped Pt nanostructured electrode with the ultrahigh electrocatalytic HER performance, excellent durability, no obvious current fluctuation, and dramatically fast current density increase at overpotential range (3.85 mA mV−1, 2.55 and 13.75 times higher than that for nanosphere electrode and for Pt flat electrode, respectively), is obtained, much superior to Pt nanosphere and flat electrodes. The successful introduction of under‐water superaerophobicity to in‐time repel as‐formed H2 bubbles may open up a new pathway for designing more efficient electrocatalysts with potentially practical utilization in the near future.
Infrared Detection Using Transparent and Flexible Field‐Effect Transistor Array with Solution Processable Nanocomposite Channel of Reduced Graphene Oxide and P(VDF‐TrFE)
Authors: Trung Tran Quang , Ramasundaram Subramaniyan , Lee Nae‐Eung
Published: February 2015

Photodetectors using optically responsive graphene (Gr) or reduced graphene oxide (R‐GO) on rigid substrates have showed promising results for detection of broad band light including infrared (IR). However, there have been only a few reports on Gr or R‐GO photodetectors with new functionalities such as optical transparency and/or flexibility. Herein, a new kind of transparent and flexible IR photodetector is presented using a field‐effect transistor (FET) structure in which an IR‐responsive nanocomposite layer of R‐GO and poly(vinylidenefluoride‐co‐trifluoroethylene) (P(VDF‐TrFE)) is employed as the channel. The IR photodetector exhibits high IR responsivity, stability, and reproducibility under mechanical strain and ambient conditions. In addition, the capability of measuring the distribution of responses from each device in the transparent and flexible nanocomposite FET array under IR radiation from the human body is also demonstrated. Therefore, the development of a flexible IR photodetector with high responsivity, transparency, ease of integration, and stability in an ambient environment is a suitable alternative approach for achieving the stable monitoring of IR in many flexible and transparent electronic systems.
Single‐Pot Encapsulation of Oxide Particles within a Polysaccharide Multilayer Nanocoating
Authors: Jankolovits Joseph , Gazit Oz M. , Nigra Michael M. , Bohling James , Roper John A. , Katz Alexander
Published: February 2015

Porous coatings on oxide surfaces are invaluable in emerging applications involving biomaterials, drug delivery, sensing, and colloidal suspensions such as paints and coatings. The synthesis of such coatings has conventionally required complex multiple‐step syntheses and petroleum‐derived polymers. In this manuscript, the single‐step synthesis of uniform nanocoatings on oxide particles is demonstrated using a one‐pot approach and glucans derived from cellulose, which enables the synthetic tunability of polymer coatings by leveraging on established sugar chemistry. The resulting ≈10 nm thick uniform coatings are synthesized by imbibing a crosslinking agent, such as SiCl4, into the pores of the oxide particle, which localizes polymer crosslinking to the immediate proximity of the inorganic‐oxide surface. The resulting nanocoatings encapsulate the particles and render the inorganic‐oxide surface inaccessible to polyanions though accessible to small molecules. The surface chemistry is tuned for enhanced dispersion stability in water by covalently introducing of carboxylates to the coating.
Band‐Gap Engineering at a Semiconductor–Crystalline Oxide Interface
Authors: Jahangir‐Moghadam Mohammadreza , Ahmadi‐Majlan Kamyar , Shen Xuan , Droubay Timothy , Bowden Mark , Chrysler Matthew , Su Dong , Chambers Scott A. , Ngai Joseph H.
Published: February 2015

The epitaxial growth of crystalline oxides on semiconductors provides a pathway to introduce new functionalities to semiconductor devices. Key to electrically coupling crystalline oxides with semiconductors to realize functional behavior is to control the manner in which their bands align at interfaces. Here, principles of band‐gap engineering traditionally used at heterojunctions between conventional semiconductors are applied to control the band offset between a single crystalline oxide and a semiconductor. Reactive molecular beam epitaxy is used to realize atomically abrupt and structurally coherent interfaces between SrZrxTi1−xO3 and Ge, in which the band‐gap of the former is enhanced with Zr content x. Structural and electrical characterization of SrZrxTi1−xO3‐Ge heterojunctions for x = 0.2 to 0.75 are presented and it is demonstrated that the band offset can be tuned from type‐II to type‐I, with the latter being verified using photoemission measurements. The type‐I band offset provides a platform to integrate the dielectric, ferroelectric, and ferromagnetic functionalities of oxides with semiconducting devices.
Analysis of the Suitability of Poly(lactic acid) in Rotational Molding Process
Authors: Greco Antonio , Maffezzoli Alfonso
Published: February 2015

This paper is aimed to study the suitability of poly(lactic acid) (PLA) for the production of biodegradable containers by rotational molding. To increase polymer toughness, PLA was plasticized with poly(ethylene glycole) (PEG), with an average molecular weight of 400 g/mol. Differential scanning calorimetry performed on neat PLA and PEG‐plasticized PLA showed that the former is characterized by a better quenchability than the latter. Neat PLA and PEG‐plasticized PLA were used for the production of rotational molding prototypes of simple shape. Owing to its very slow crystallization kinetics, a completely amorphous PLA was obtained by rotational molding with air cooling. As a consequence, rotomolded PLA is characterized by a good ductility and toughness. In contrast, the higher crystallization rate induced by the addition of PEG did not allow to obtain an amorphous structure for plasticized PLA, even if faster cooling was attained by water spraying. As a consequence, the PEG‐plasticized PLA, characterized by a semicrystalline structure, shows a lower ductility and toughness compared to neat PLA.
Xenon‐MRT an lebenden Zellen mit Hyper‐CEST‐Biosensoren für metabolisch markierte Glykane an der Zelloberfläche
Authors: Witte Christopher , Martos Vera , Rose Honor May , Reinke Stefan , Klippel Stefan , Schröder Leif , Hackenberger Christian P. R.
Published: February 2015

Das Targeting von metabolisch markierten Glykanen mit herkömmlichen MRT‐Kontrastmitteln erschien bislang als nicht realisierbar. Hier erweitern wir die Anwendungen von Xenon‐Hyper‐CEST‐Biosensoren in Zellen und präsentieren damit die erste erfolgreiche molekulare Bildgebung dieser Glykane mittels MRT. Hyper‐CEST‐Biosensoren sind eine neue Klasse von MRT‐Kontrastmitteln mit sehr hoher Empfindlichkeit. Darauf basierend wurde ein multimodaler Biosensor für sowohl Fluoreszenz‐ als auch Xenon‐MRT‐Detektion entwickelt, der selektiv mit metabolisch markierten Sialinsäuren durch bioorthogonale Chemie verknüpft wurde. Die Verwendung eines kürzlich entwickelten Bioreaktors zur Untersuchung lebender Zellen ermöglicht somit den Nachweis von Zelloberflächenglykanen mittels Xenon‐MRT bei nanomolaren Konzentrationen.
Combinatorial Library Based Engineering of Candida antarctica Lipase A for Enantioselective Transacylation of sec‐Alcohols in Organic Solvent
Authors: Wikmark Ylva , Svedendahl Humble Maria , Bäckvall Jan‐E.
Published: February 2015

A method for determining lipase enantioselectivity in the transacylation of sec‐alcohols in organic solvent was developed. The method was applied to a model library of Candida antarctica lipase A (CalA) variants for improved enantioselectivity (E values) in the kinetic resolution of 1‐phenylethanol in isooctane. A focused combinatorial gene library simultaneously targeting seven positions in the enzyme active site was designed. Enzyme variants were immobilized on nickel‐coated 96‐well microtiter plates through a histidine tag (His6‐tag), screened for transacylation of 1‐phenylethanol in isooctane, and analyzed by GC. The highest enantioselectivity was shown by the double mutant Y93L/L367I. This enzyme variant gave an E value of 100 (R), which is a dramatic improvement on the wild‐type CalA (E=3). This variant also showed high to excellent enantioselectivity for other secondary alcohols tested.
Fixierung und Freisetzung von intakten E4‐Tetraedern (E=P, As)
Authors: Spitzer Fabian , Sierka Marek , Latronico Mario , Mastrorilli Piero , Virovets Alexander V. , Scheer Manfred
Published: February 2015

Durch die Reaktion von [NacnacCuCH3CN] mit weißem Phosphor (P4) und gelbem Arsen (As4) werden die Stabilisierung und der Einschluss von intakten E4‐Tetraedern realisiert, und es bilden sich die zweifach‐substituierten Komplexe [(NacnacCu)2(μ,η2:2‐E4)] (1 a: E=P, 1 b: E=As). Der monosubstituierte Komplex [NacnacCu(η2‐P4)] (2) wurde in einer Austauschreaktion von 1 a mit P4 detektiert und nur durch Aufarbeitung bei tiefen Temperaturen isoliert. Alle Produkte wurden umfassend spektroskopisch und kristallographisch charakterisiert. Die Bindungsverhältnisse in den Produkten als intakte E4‐Einheiten (E=P, As) wurden durch theoretische Studien bestätigt und experimentell durch die Pyridin‐geförderte Freisetzung der verbrückenden E4‐Tetraeder in 1 bewiesen.
Live‐cell MRI with Xenon Hyper‐CEST Biosensors Targeted to Metabolically Labeled Cell‐Surface Glycans
Authors: Witte Christopher , Martos Vera , Rose Honor May , Reinke Stefan , Klippel Stefan , Schröder Leif , Hackenberger Christian P. R.
Published: February 2015

The targeting of metabolically labeled glycans with conventional MRI contrast agents has proved elusive. In this work, which further expands the utility of xenon Hyper‐CEST biosensors in cell experiments, we present the first successful molecular imaging of such glycans using MRI. Xenon Hyper‐CEST biosensors are a novel class of MRI contrast agents with very high sensitivity. We designed a multimodal biosensor for both fluorescent and xenon MRI detection that is targeted to metabolically labeled sialic acid through bioorthogonal chemistry. Through the use of a state of the art live‐cell bioreactor, it was demonstrated that xenon MRI biosensors can be used to image cell‐surface glycans at nanomolar concentrations.
Porous Solids Arising from Synergistic and Competing Modes of Assembly: Combining Coordination Chemistry and Covalent Bond Formation
Authors: Dutta Ananya , Koh Kyoungmoo , Wong‐Foy Antek G. , Matzger Adam J.
Published: February 2015

Design and synthesis of porous solids employing both reversible coordination chemistry and reversible covalent bond formation is described. The combination of two different linkage modes in a single material presents a link between two distinct classes of porous materials as exemplified by metal–organic frameworks (MOFs) and covalent organic frameworks (COFs). This strategy, in addition to being a compelling material‐discovery method, also offers a platform for developing a fundamental understanding of the factors influencing the competing modes of assembly. We also demonstrate that even temporary formation of reversible connections between components may be leveraged to make new phases thus offering design routes to polymorphic frameworks. Moreover, this approach has the striking potential of providing a rich landscape of structurally complex materials from commercially available or readily accessible feedstocks.
Manganese dioxide and N,N′,N″‐trihydroxyisocyanuric acid: a novel and recyclable catalytic system for aerobic oxidation of toluene derivatives in PEG‐1000‐based dicationic acidic ionic liquid
Authors: Lu Tingting , Zhang Lijie , Ge Zhongxue , Ji Yueping , Lu Ming
Published: February 2015

N,N′,N″‐trihydroxyisocyanuric acid (THICA) with MnO2 promotes the aerobic oxidation of toluene derivatives to corresponding acids in PEG‐1000‐based dicationic acidic ionic liquid (PEG1000–DAIL). It is demonstrated that THICA/MnO2 is very active and selective and several toluene derivatives are efficiently oxidized to corresponding acids under mild conditions. Both the catalyst and PEG1000–DAIL can be reused after simple separation. A plausible mechanism is also proposed based on the experimental observations. Copyright © 2015 John Wiley & Sons, Ltd.
Nickel‐Promoted Highly Regioselective Carboxylation of Aryl Ynol Ether and Its Application to the Synthesis of Chiral β‐Aryloxypropionic Acid Derivatives
Authors: Saito Nozomi , Sun Zhongdong , Sato Yoshihiro
Published: February 2015

Nickel(0)‐promoted carboxylation of aryl ynol ether proceeded in a highly regioselective manner to produce α‐substituted‐β‐aryloxyacrylic acid derivatives. The α‐substituted‐β‐aryloxyacrylic acids were transformed into the corresponding β‐aryloxypropionic acid derivative as an optically active form via rhodium‐catalyzed asymmetric hydrogenation.
Self‐Assembly of a Au16 Ring via Metal–Metal Bonding Interactions
Authors: Wang Ya‐Qing , Jiang Xuan‐Feng , Li Hao , Yu Shu‐Yan
Published: February 2015

Metal–metal bonding interactions have been employed as an efficient strategy to generate a number of unique gold(I) metallo‐macrocycles with fascinating functions. The self‐assembly, crystal structure and emission property of novel nest‐like tetramer 14, namely, {[Au4(μ‐dppm)2(μ‐dctp2−)](BF4)2}4⋅(CH3CN)2 (dppm=bis(diphenylphosphino)methane, dctp2−=N,N′‐bis(dicarbodithioate)‐2,11‐diaza[3.3]paracyclophane) is reported. The complex has been characterized by single‐crystal X‐ray diffraction analysis, 1H NMR spectroscopy, 13C NMR spectroscopy, and CSI‐MS spectrometry. The aggregate demonstrates the sixteen gold(I) atoms are arranged in a ring with a circumference of 50.011(68) Å generated by AuI⋅⋅⋅AuI attractions. UV/visible and luminescence spectroscopy revealed that this AuI⋅⋅⋅AuI bonded metallo‐macrocycle exhibited yellow phosphorescence.
Synthesis and Predetermined Supramolecular Chirality of Carbohydrate‐Functionalized Perylene Bisimide Derivatives
Authors: Wang Ke‐Rang , Han Dan , Cao Guo‐Jing , Li Xiao‐Liu
Published: February 2015

Eight carbohydrate‐modified perylene bisimides (PBI‐4 lac‐2 lac, PBI‐4 lac‐2 Man, PBI‐4 lac‐2 Gal, PBI‐4 lac‐2 Mal, PBI‐4 Man‐2 Man, PBI‐4 Man‐2 lac, PBI‐4 Man‐2 Gal and PBI‐4 Man‐2 Mal) were synthesized, and the following predetermined supramolecular chirality rule was found: perylene bisimides modified with disaccharides (D‐lactose and D‐maltose) at the imide position generated right‐handed chirality, and those modified with monosaccharides (D‐mannose and D‐galactose) generated left‐handed chirality, when D‐lactose or D‐mannose was substituted in the bay positions of perylene bisimides with amide bonds as the linking spacers. These results may be because of the difference in the stacking angle of the perylene bisimide backbones induced by the steric effect and the additional hydrogen bonds between the disaccharide residues. This study provides an important design rule for predetermined chiral self‐assembly of perylene bisimides.
A General Direct Arylation of Polyfluoroarenes with Heteroaryl and Aryl Chlorides Catalyzed by Palladium Indolylphosphine Complexes
Authors: Yuen On Ying , Charoensak Mueangkaew , So Chau Ming , Kuhakarn Chutima , Kwong Fuk Yee
Published: February 2015

The first general examples of direct coupling of heteroaryl chlorides, especially substituted 2‐pyridyl chlorides which were previously found to be problematic, with electron‐deficient polyfluoroarenes are reported. Pd(OAc)2 associated with 3‐(dicyclohexylphosphino)‐2‐phenylindole L1 serves as the effective catalyst which allows the challenging direct coupling of heteroaryl chlorides and polyfluoroarenes. In addition to heterocycles, a wide range of non‐activated and activated aryl chlorides and alkenyl chlorides were also applicable under this catalyst system. A catalyst loading down to 1 mol % Pd can be achieved.
Dynamical quenching with non‐local α and downward pumping
Authors: Brandenburg A. , Hubbard A. , Käpylä P.J.
Published: February 2015

In light of new results, the one‐dimensional mean‐field dynamo model of Brandenburg & Käpylä (2007) with dynamical quenching and a nonlocal Babcock‐Leighton α effect is re‐examined for the solar dynamo. We extend the one‐dimensional model to include the effects of turbulent downward pumping (Kitchatinov & Olemskoy 2011), and to combine dynamical quenching with shear. We use both the conventional dynamical quenching model of Kleeorin & Ruzmaikin (1982) and the alternate one of Hubbard & Brandenburg (2011), and confirm that with varying levels of non‐locality in the α effect, and possibly shear as well, the saturation field strength can be independent of the magnetic Reynolds number. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Atypical Face Perception in Autism: A Point of View?
Authors: Morin Karine , Guy Jacalyn , Habak Claudine , Wilson Hugh R. , Pagani Linda , Mottron Laurent , Bertone Armando
Published: February 2015

Face perception is the most commonly used visual metric of social perception in autism. However, when found to be atypical, the origin of face perception differences in autism is contentious. One hypothesis proposes that a locally oriented visual analysis, characteristic of individuals with autism, ultimately affects performance on face tasks where a global analysis is optimal. The objective of this study was to evaluate this hypothesis by assessing face identity discrimination with synthetic faces presented with and without changes in viewpoint, with the former condition minimizing access to local face attributes used for identity discrimination. Twenty‐eight individuals with autism and 30 neurotypical participants performed a face identity discrimination task. Stimuli were synthetic faces extracted from traditional face photographs in both front and 20° side viewpoints, digitized from 37 points to provide a continuous measure of facial geometry. Face identity discrimination thresholds were obtained using a two‐alternative, temporal forced choice match‐to‐sample paradigm. Analyses revealed an interaction between group and condition, with group differences found only for the viewpoint change condition, where performance in the autism group was decreased compared to that of neurotypical participants. The selective decrease in performance for the viewpoint change condition suggests that face identity discrimination in autism is more difficult when access to local cues is minimized, and/or when dependence on integrative analysis is increased. These results lend support to a perceptual contribution of atypical face perception in autism. Autism Res 2015, 8: 497–506. © 2015 International Society for Autism Research, Wiley Periodicals, Inc.
Molecular cloning and expression of a new α‐neoagarobiose hydrolase from Agarivorans gilvus WH0801 and enzymatic production of 3,6‐anhydro‐l‐galactose
Authors: Liu Nan , Yang Meng , Mao Xiangzhao , Mu Bozhong , Wei Dongzhi
Published: February 2015

A new α‐neoagarobiose hydrolase (NABH) called AgaWH117 was cloned from Agarivorans gilvus WH0801. The gene encoding this hydrolase consists of 1,086 bp and encodes a protein containing 361 amino acids. This new NABH showed 74% amino acid sequence identity with other known NABHs. The molecular mass of the recombinant AgaWH117 was estimated to be 41 kDa. Purified AgaWH117 showed endolytic activity during neoagarobiose degradation, yielding 3,6‐anhydro‐l‐galactose (l‐AHG) and d‐galactose as products. It showed a maximum activity at a temperature of 30 °C and a pH of 6.0 and was stable at temperatures below 30 °C. Its Km and Vmax values were 2.094 mg/mL and 6.982 U/mg, respectively. The cloning strategy used and AgaWH117 isolated in this study will provide information on the saccharification process of marine biomass. This study provides a method to produce l‐AHG from agarose by using AgaWH117 without an acid and describes its one‐step purification by using Bio‐Gel P2 chromatography.
Spectroscopic study of the interaction between adenosine disodium triphosphate and gatifloxacin–Al3+ complex and its analytical application
Authors: Kamruzzaman Mohammad , Faruqui A. Nayeem , Hossain Mohammed Ifteker , Lee Sang Hak
Published: February 2015

A new and sensitive spectrofluorimetric method has been proposed to determine trace amount of adenosine disodium triphosphate (ATP). The method is based on the fluorimetric interaction between gatifloxacin (GFLX)–aluminium (III) (Al3+) complex and ATP and studied using UV‐visible and fluorescence spectroscopy. Weak luminescence spectra of Al3+ were enhanced after complexation with GFLX at 423 nm upon excitation at 272 nm due to energy transfer from the ligand to the Al3+ ion. It was observed that the FL emission spectrum of GFLX–Al3+ was enhanced significantly by the addition of ATP. Under the optimal conditions, the enhancement of FL intensity at 423 nm was responded linearly with the concentration of ATP in the range 1.3 × 10–10 – 1.0 × 10–8 mol L–1 with correlation coefficient (r) of 0.9981. The limit of detection (LOD) was found to be 1.1 × 10–11 mol L–1 for ATP with the standard deviation (RSD) of 1.21% for five repeated measurement of 2.3 × 10–8 mol L–1 ATP. The presented method is simple, sensitive, free from coexisting interferents and can be applied successfully to determine ATP in the real samples. Copyright © 2015 John Wiley & Sons, Ltd.
Plant‐made vaccines against West Nile virus are potent, safe, and economically feasible
Authors: Chen Qiang
Published: February 2015

The threat of West Nile virus (WNV) epidemics with increasingly severe neuroinvasive infections demands the development and licensing of effective vaccines. To date, vaccine candidates based on inactivated, live‐attenuated, or chimeric virus, and viral DNA and WNV protein subunits have been developed. Some have been approved for veterinary use or are under clinical investigation, yet no vaccine has been licensed for human use. Reaching the milestone of a commercialized human vaccine, however, may largely depend on the economics of vaccine production. Analysis suggests that currently only novel low‐cost production technologies would allow vaccination to outcompete the cost of surveillance and clinical treatment. Here, we review progress using plants to address the economic challenges of WNV vaccine production. The advantages of plants as hosts for vaccine production in cost, speed and scalability, especially those of viral vector‐based transient expression systems, are discussed. The progress in developing WNV subunit vaccines in plants is reviewed within the context of their expression, characterization, downstream processing, and immunogenicity in animal models. The development of vaccines based on enveloped and non‐enveloped virus‐like particles is also discussed. These advancements suggest that plants may provide a production platform that offers potent, safe and affordable human vaccines against WNV.
Rational and efficient site‐directed mutagenesis of adenylation domain alters relative yields of luminmide derivatives in vivo
Authors: Bian Xiaoying , Plaza Alberto , Yan Fu , Zhang Youming , Müller Rolf
Published: February 2015

Cloning and engineering of natural product biosynthetic pathways followed by heterologous expression in a tractable host is a widely used approach for expression and genetic modification of microbial secondary metabolites. Herein, we employed ccdB counterselection combined with oligonucleotide‐mediated recombineering to efficiently create point mutations in a complex nonribosomal peptide synthetase (NRPS) from Photorabdus luminescens directing the biosynthesis of luminmides. After in depth analysis of the luminmide production profile from the native NRPS, single and double point mutations were rationally constructed within the adenylation (A) domain from NRPS module 3 which turned out to have a broad substrate tolerance. Expression of mutated versions of the 15.6 kb NRPS gene plu3263 in E. coli led to alterations in luminmide production profiles and allowed to direct the biosynthesis towards certain derivatives. These results demonstrate the suitability of counterselection recombineering for site‐directed mutagenesis of complex expression constructs, e.g., genes encoding NRPS biosynthetic pathways in multi‐copy plasmids. Biotechnol. Bioeng. 2015;112: 1343–1353. © 2015 Wiley Periodicals, Inc.
Überlebensstrategien von Regenwaldameisen
Authors: Maschwitz Ulrich , Moog Joachim
Published: February 2015

Die heftigen Regenfälle in den feuchten Tropen stellen Pflanzen und Tiere vor besondere Herausforderungen. Ameisen haben unterschiedliche Anpassungen gegen Überflutungen entwickelt. Von der Floßbildung bis zu verschiedenen Methoden der Nestentwässerung reichen die Maßnahmen gegen Hochwasser. In der Gezeitenzone werden Nester wasserdicht verschlossen, dabei reagieren die Ameisen mit physiologischen Anpassungen auf den Sauerstoffmangel. In einer obligaten Symbiose zwischen einer carnivoren Kannenpflanze und einer Rossameise hat sich ein einzigartiges Zusammenleben entwickelt, bei der die Partnerameise unbeschadet in dem enzymhaltigen Kannenwasser schwimmt und nach Mückenlarven und ertrunkenen Beutetieren taucht.
Väterliche Mitgift für die Zygote
Authors: Kronberg Inge
Published: February 2015

Das Leben jedes mehrzelligen Organismus beginnt mit der Verschmelzung von Ei‐ und Spermienzelle zur Zygote. Die Beiträge der maternalen und paternalen Keimzellen zur Zygote sind dabei recht unterschiedlich: Die Eizelle liefert neben dem haploiden mütterlichen Chromosomensatz auch Zellplasma und Mitochondrien, die Spermienzelle scheinbar nur den haploiden väterlichen Chromosomensatz. Die Entdeckung winziger paternaler RNA‐Schnipsel, die von Spermienzellen auf die Zygote übertragen werden, ist insofern eine Überraschung. Ähnlich wie die maternalen Faktoren kann diese Mitgift nicht nur bei der Entwicklung der Zygote eine Rolle spielen, sondern auch in die epigenetische Vererbung eingreifen.
Determination of GDC‐0980 (apitolisib), a small molecule dual phosphatidylinositide 3‐kinase/mammalian target of rapamycin inhibitor in dog plasma by LC‐MS/MS to support a GLP toxicology study
Authors: Ding Xiao , Salphati Laurent , Kim Amy , Morinello Eric , Wong Lisa , Pang Jodie , Percey Shaundel , Meng Min , Reuschel Scott , Dean Brian
Published: February 2015

An LC‐MS/MS method for the determination of GDC‐0980 (apitolisib) concentrations in dog plasma has been developed and validated for the first time to support pre‐clinical drug development. Following protein precipitation with acetonitrile, the resulting samples were analyzed using reverse‐phase chromatography on a Metasil AQ column. The mass analysis was performed on a triple quadruple mass spectrometer coupled with an electrospray interface in positive ionization mode. The selected reaction monitoring transitions monitored were m/z 499.3 → 341.1 for GDC‐0980 and m/z 507.3 → 341.1 for IS. The method was validated over the calibration curve range 0.250–250 ng/mL with linear regression and 1/x2 weighting. Relative standard deviation (RSD) ranged from 0.0 to 10.9% and accuracy ranged from 93.4 to 113.6% of nominal. Stable‐labeled internal standard GDC‐0980‐d8 was used to minimize matrix effects. This assay was used for the measurement of GDC‐0980 dog plasma concentrations to determine toxicokinetic parameters after oral administration of GDC‐0980 (0.03, 0.1 and 0.3 mg/kg) to beagle dogs in a GLP toxicology study. Peak concentration ranged from 3.23 to 84.9 ng/mL. GDC‐0980 was rapidly absorbed with a mean time to peak concentration ranging from 1.3 to 2.4 h. Mean area under the concentration–time curve from 0 to 24 hours ranged from 54.4 to 542 ng h/mL. Copyright © 2015 John Wiley & Sons, Ltd.
Determination of triapine, a ribonucleotide reductase inhibitor, in human plasma by liquid chromatography tandem mass spectrometry
Authors: Feng Ye , Kunos Charles A. , Xu Yan
Published: February 2015

Triapine is an inhibitor of ribonucleotide reductase (RNR). Studies have shown that triapine significantly decreases the activity of RNR and enhanced the radiation‐mediated cytotoxicity in cervical and colon cancer. In this work, we have developed and validated a selective and sensitive LC‐MS/MS method for the determination of triapine in human plasma. In this method, 2‐[(3‐fluoro‐2‐pyridinyl)methylene] hydrazinecarbothioamide (NSC 266749) was used as the internal standard (IS); plasma samples were prepared by deproteinization with acetonitrile; tripaine and the IS were separated on a Waters Xbridge Shield RP18 column (3.5 µm; 2.1 × 50 mm) using a mobile phase containing 25.0% methanol and 75.0% ammonium bicarbonate buffer (10.0 mm, pH 8.50; v/v); column eluate was monitored by positive turbo‐ionspray tandem mass spectrometry; and quantitation of triapine was carried out in multiple‐reaction‐monitoring mode. The method developed had a linear calibration range of 0.250–50.0 ng/mL with correlation coefficient of 0.999 for triapine in human plasma. The IS‐normalized recovery and the IS‐normalized matrix factor of triapine were 101–104% and 0.89–1.05, respectively. The accuracy expressed as percentage error and precision expressed as coefficient of variation were ≤±6 and ≤8%, respectively. The validated LC‐MS/MS method was applied to the measurement of triapine in patient samples from a phase I clinical trial. Copyright © 2015 John Wiley & Sons, Ltd.
Metabolic profiles of dioscin in rats revealed by ultra‐performance liquid chromatography quadrupole time‐of‐flight mass spectrometry
Authors: Zhu He , Xu Jin‐Di , Mao Qian , Shen Hong , Kong Ming , Chen Jian‐Ping , Li Song‐Lin
Published: February 2015

Dioscin (DIS), one of the most abundant bioactive steroidal saponins in Dioscorea sp., is used as a complementary medicine to treat coronary disease and angina pectoris in China. Although the pharmacological activities and pharmacokinetics of DIS have been well demonstrated, information regarding the final metabolic fates is very limited. This study investigated the in vivo metabolic profiles of DIS after oral administration by ultra‐performance liquid chromatography quadrupole time‐of‐flight mass spectrometry method. The structures of the metabolites were identified and tentatively characterized by means of comparing the molecular mass, retention time and fragmentation pattern of the analytes with those of the parent compound. A total of eight metabolites, including seven phase I and one phase II metabolites, were detected and tentatively identified for the first time. Oxidation, deglycosylation and glucuronidation were found to be the major metabolic processes of the compound in rats. In addition, a possible metabolic pathway on the biotransformation of DIS in vivo was proposed. This study provides valuable and new information on the metabolism of DIS, which will be helpful for further understanding its mechanism of action. Copyright © 2015 John Wiley & Sons, Ltd.
A simple high‐performance liquid chromatography for the determination of linezolid in human plasma and saliva
Authors: Hara Shuuji , Uchiyama Masanobu , Yoshinari Masami , Matsumoto Taichi , Jimi Shiro , Togawa Atsushi , Takata Tohru , Takamatsu Yasushi
Published: February 2015

Linezolid is an antimicrobial agent for the treatment of multiresistant Gram‐positive infections. A practical high‐performance liquid chromatography method was developed for the determination of linezolid in human plasma and saliva. Linezolid and an internal standard (o‐ethoxybenzamide) were extracted from plasma and saliva with ethyl acetate and analyzed on a Capcell Pak C18 MG column with UV detection at 254 nm. The calibration curve was linear through the range 0.5–50 µg/mL using a 200 μL sample volume. The intra‐ and interday precisions were all <6.44% for plasma and 5.60% for saliva. The accuracies ranged from 98.8 to 110% for both matrices. The mean recoveries of linezolid were 80.8% for plasma and 79.0% for saliva. This method was used to determine the plasma and saliva concentrations of linezolid in healthy volunteers who were orally administered a 600 mg dose of linezolid. Our liquid–liquid extraction procedure is easy and requires a small volume of plasma or saliva (200 μL). This small volume can be advantageous in clinical pharmacokinetic studies, especially if children participate. Copyright © 2015 John Wiley & Sons, Ltd.
Learn how to communicate during a crisis so it doesn't become a media disaster
Authors: Minkoff Randy
Published: February 2015

When I was a young legislative reporter for United Press International in the 1970s, we had a term for lawmakers who wouldn't talk during a crisis: “putting your head in the sand.”
Tread carefully when handling personnel‐related decisions
Authors: O'Brien Timothy
Published: February 2015

College athletics administrators are called upon to make more employment decisions than almost any other department in a college or university. From coaches, operations directors and athletic trainers to facility and ticket managers, the list of involved individuals can go on and on.
Cyclopentenone Derivatives and Polyhydroxylated Steroids from the Soft Coral Sinularia acuta
Authors: Zhang Nai‐Xia , Tang Xu‐Li , van Ofwegen Leen , Xue Lei , Song Wen‐Juan , Li Ping‐Lin , Li Guo‐Qiang
Published: February 2015

Four new polyhydroxylated steroids, 1–4, and the racemic form of cyclopentenone 9, together with four known steroids, 5–8, one known cyclopentenone derivative, 10, and one known butenolide derivative, 11, were isolated from the soft coral Sinularia acuta collected from Weizhou Island of Guangxi Province, P. R. China. Their structures were elucidated on the basis of spectroscopic analyses and by comparison of the corresponding data with those previously reported. The cytotoxicities of the isolates 1–11 in vitro against the selected tumor cell lines HL‐60, HeLa, and K562 were evaluated. Compounds 2 and 5 showed potent cytotoxicities against HL‐60 cell lines with IC50 values of 7.3 and 9.9 μM, respectively. Compounds 5 and 6 showed moderate activities against K562 cell lines with IC50 values of 10.9 and 11.7 μM, respectively, while compounds 1, 2, and 6 showed weak activities against HeLa cell lines with respective IC50 values of 44.8, 27.1, and 18.2 μM. This is the first report on chemical and bioactivity research of S. acuta.
Activities of Wogonin Analogs and Other Flavones against Flavobacterium columnare
Authors: Tan Cheng‐Xia , Schrader Kevin K. , Khan Ikhlas A. , Rimando Agnes M.
Published: February 2015

In our on‐going pursuit to discover natural products and natural product‐based compounds to control the bacterial species Flavobacterium columnare, which causes columnaris disease in channel catfish (Ictalurus punctatus), we synthesized flavone and chalcone analogs, and evaluated these compounds, along with flavonoids from natural sources, for their antibacterial activities against two isolates of F. columnare (ALM‐00‐173 and BioMed) using a rapid bioassay. The flavonoids chrysin (1a), 5,7‐dihydroxy‐4′‐methoxyflavone (11), isorhamnetin (26), luteolin (27), and biochanin A (29), and chalcone derivative 8b showed strong antibacterial activities against F. columnare ALM‐00‐173 based on minimum inhibition concentration (MIC) results. Flavonoids 1a, 8, 11, 13 (5,4′‐dihydroxy‐7‐methoxyflavone), 26, and 29 exhibited strong antibacterial activities against F. columnare BioMed based upon MIC results. The 24‐h 50% inhibition concentration (IC50) results revealed that 27 and 29 were the most active compounds against F. columnare ALM‐00‐173 (IC50 of 7.5 and 8.5 mg/l, resp.), while 26 and 29 were the most toxic compound against F. columnare BioMed (IC50 of 9.2 and 3.5 mg/l, resp.). These IC50 results were lower than those obtained for wogonin against F. columnare ALM‐00‐173 and F. columnare BioMed (28.4 and 5.4 mg/l, resp.). However, based on MIC results, none of the compounds evaluated in this study were as active as wogonin (MIC 0.3 mg/l for each F. columnare isolate). Further modification of the wogonin structure to enhance antibacterial is of interest.
Xylella fastidiosa Esterase Rather than Hydroxynitrile Lyase
Authors: Torrelo Guzman , Ribeiro de Souza Fayene Zeferino , Carrilho Emanuel , Hanefeld Ulf
Published: February 2015

In 2009, we reported that the product of the gene SCJ21.16 (XFa0032) from Xylella fastidiosa, a xylem‐restricted plant pathogen that causes a range of diseases in several important crops, encodes a protein (XfHNL) with putative hydroxynitrile lyase activity. Sequence analysis and activity tests indicated that XfHNL exhibits an α/β‐hydrolase fold and could be classified as a member of the family of FAD‐independent HNLs. Here we provide a more detailed sequence analysis and new experimental data. Using pure heterologously expressed XfHNL we show that this enzyme cannot catalyse the cleavage/synthesis of mandelonitrile and that this protein is in fact a non‐enantioselective esterase. Homology modelling and ligand docking simulations were used to study the active site and support these results. This finding could help elucidate the common ancestor of esterases and hydroxynitrile lyases with an α/β ‐hydrolase fold.