bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thionitrosyl‐ and Selenonitrosyliridium Complexes
Authors: Scheibel Markus G. , Klopsch Isabel , Wolf Hilke , Stollberg Peter , Stalke Dietmar , Schneider Sven 
Published: August 2013

AbstractThe activation of elemental sulfur and selenium with electrophilic iridium nitride [Ir(N){N(CHCHPtBu2)2}]+ allowed the synthesis of thionitrosyl‐ and selenonitrosyliridium complexes. The crystallographic and spectroscopic characterization of this rare series of chalcogenonitrosyl complexes [Ir(NE){N(CHCHPtBu2)2}]+ (E = none, O, S, Se) is discussed in the context of bonding models. The experimental results indicate strong Ir–N–E multiple‐bond character, in agreement with the previously proposed N–E donor–acceptor interaction as an appropriate description for the heavier chalcogens.
Recent Developments in Amide Synthesis: Direct Amidation of Carboxylic Acids and Transamidation Reactions
Authors: Lanigan Rachel M. , Sheppard Tom D. 
Published: August 2013

AbstractThe synthesis of amides is of huge importance in a wide variety of industrial and academic fields and is of particular significance in the synthesis of pharmaceuticals. Many of the well established methods for amide synthesis involve reagents that are difficult to handle and lead to the generation of large quantities of waste products. As a consequence, there has been a considerable amount of interest in the development of new approaches to amide synthesis. Over the past few years a wide range of new reagents and catalysts for direct amidation of carboxylic acids have been reported. In addition, the interconversion of amide derivatives through transamidation is emerging as a potential alternative strategy for accessing certain amides. This microreview covers recent developments in the direct amidation of carboxylic acids and the interconversion of amides through transamidation. The advantages and disadvantages of the various methods are discussed, as well as the possible mechanisms of the reactions.
Diversity‐Oriented Synthesis of Enantiopure Furofurans from Carbohydrates: An Expedient Approach with Built‐in Michael Acceptor, Masked Aldehyde and Leaving Group in a Single Sugar Derivative
Authors: Manna Chinmoy , Pathak Tanmaya 
Published: August 2013

AbstractA single sugar molecule containing three functional groups, namely a masked aldehyde, a Michael acceptor and a leaving group, reacts with a series of β‐dicarbonyl compounds and related reagents to form up to three new bonds and up to three new stereocenters. The configuration of the sugar derivative controls the diastereoselectivity in the formation of all the new bonds without a requirement for any external reagent for asymmetric induction. This “Chiral pool” based diversity‐oriented synthetic strategy has led to the formation of a series of furofurans based on different scaffolds and with appendage variations, and also to a hitherto unknown family of bicyclic 3,8‐dioxabicyclo[4.2.1]nonanes.
Cycloaddition versus Alkylation Reactions of 2‐Vinylindoles with α,β‐Unsaturated Carbonyl Compounds Under Gold Catalysis
Authors: Pirovano Valentina , Dell'Acqua Monica , Facoetti Diego , Nava Donatella , Rizzato Silvia , Abbiati Giorgio , Rossi Elisabetta 
Published: August 2013

AbstractThe gold‐catalyzed intermolecular Diels–Alder cycloaddition and competitive Michael addition reactions between 2‐vinylindoles and enones/enals are reported. The reaction outcome strictly correlates with the electronic character of the heteroaromatic substrate. Thus, Diels–Alder cycloadducts are the sole products in the presence of less electron‐rich heterocycles, whereas Michael addition adducts are observed with more electron‐rich heterocycles. Plausible competitive reaction mechanisms are proposed and discussed as well.
Gradient augmented reinitialization scheme for the level set method
Authors: Anumolu Lakshman , Trujillo Mario F. 
Published: August 2013

SUMMARYA hybrid scheme for reinitializing the level set function and its gradient within the frame work of the augmented level set method is presented. It is based on first dividing the domain into an interfacial region (i.e. nodes close to the interface) and its complement. Within the interfacial region, the level set and its gradient are updated explicitly through a modified version of Newton's method (Chopp, 2001, SIAM J. Sci. Comput. 23 230‐244) and is implemented here within the context of Hermite polynomials. In the region away from the interface, the solution pertains to a semi‐Lagrangian implementation of the reinitialization equations, which are solved based on Hermite polynomials and are time marched with a single step and a multipoint scheme. It is shown that for various exercises, the present method predicts the signed distance function and its gradient to 4th and 3rd order (in space), respectively with regards to the L1, L2, and L ∞  norms, provided the level set field is sufficiently smooth. A range of test cases are also considered from the literature, where the present method is compared with existing methods and shown to be generally more accurate. Moreover, the well‐known issue of volume loss due to reinitialization is addressed successfully with the current implementation, even for objects that are of the size of one grid cell, and whose local radius of curvature falls below the local grid size. For both time marching schemes, it is shown that the L2 and L ∞  errors decay to negligible levels, are smooth in space, and do not exhibit temporal oscillations. Finally the performance of the hybrid scheme is evaluated by applying it on various kinematic test cases. For solid body rotation problems (zero deformation flow field), the benefit stemming from hybrid reinitialization is marginal. When applied to kinematic cases involving severe deformation, such as the standard vortex flow, the reinitialization strategy helps maintain a smooth level set field, which prevents serious numerical errors from developing.Copyright © 2013 John Wiley & Sons, Ltd.
Implication of the chemokine CCL2 in trigeminal nociception and traumatic neuropathic orofacial pain
Authors: Dauvergne C. , Molet J. , Reaux‐Le Goazigo A. , Mauborgne A. , Mélik‐Parsadaniantz S. , Boucher Y. , Pohl M. 
Published: August 2013

AbstractBackgroundChemokine (C‐C motif) ligand 2 (CCL2) participates in different mechanisms contributing to the spinal cord inflammation and pain development after sciatic nerve injury. Recent data also support its role in orofacial thermal hypersensitivity, although its implication in different phases of trigeminal pain emergence is unclear. We assessed the importance of CCL2 signalling in biochemical and behavioural alterations during the early and late stages following chronic constriction injury of infraorbital nerve (ION‐CCI), a model of peripheral traumatic trigeminal pain.MethodsAfter evaluating the consequences of CCL2 intracisternal injection in naïve rats, we determined the expression changes for CCL2, inflammatory and glia activation markers in the somatosensory trigeminal complex (STC) and trigeminal ganglia (TG) after ION‐CCI. The role of CCL2 signalling was assessed using pre‐emptive or ‘curative’ intracisternal treatment with specific CCL2 receptor antagonist – INCB3344.ResultsExogenous CCL2 evoked spontaneous behaviour reminiscent of orofacial pain and marked mechanical hypersensitivity, associated with increased expression of proinflammatory cytokines and glial markers in STC and TG. CCL2‐evoked changes were prevented by the co‐administration of INCB3344. Two weeks after ION‐CCI, mRNA for CCL2, glial and inflammatory markers were up‐regulated, and CCL2‐immunoreactivity accumulated in central and ganglionic tissues. At this time, repeated intracisternal administration of INCB3344 did not attenuate the ION‐CCI‐associated behavioural nor biochemical changes. By contrast, pre‐emptive INCB3344 treatment delayed the emergence of trigeminal mechanical allodynia and associated biochemical alterations.ConclusionsOur data suggest that CCL2 is involved principally in the early events accompanying the ION lesion rather than in long‐term alterations and the maintenance of trigeminal mechanical hypersensitivity.
Immunoelectron microscopic observation of connexin43 in rat odontoblasts
Authors: Muramatsu Takashi , Hashimoto Sadamitsu , Shibukawa Yoshiyuki , Yuasa Kazuhiro , Furusawa Masahiro , Shimono Masaki 
Published: August 2013

ABSTRACTGap junctions play an important role in differentiation of odontoblasts. Gap junction protein, connexin 43 is expressed in odontoblast. However, the detailed localization in odontoblasts has yet to be fully investigated. We investigated the localization of connexin43 in rat odontoblasts immuno‐electron microscopically. The rats were transcardially fixed with 1% paraformaldehyde in 0.1M phosphate buffer, and mandibles were decalcified with 10% ethylenediamine tetraacetic acid. Pre‐embedding method was carried out for immuno‐electron microscopic analysis. Microscopically, gap junctions were localized between bodies of odontoblasts, and between bodies and processes of odontoblasts. The gap junctions were labeled with gold particles that indicated connexin43. These results suggest that gap junctions between odontoblasts are definitely composed of connexin43 in rats, and our methods used in this study is useful to investigate localization of connexin43 immuno‐electron microscopically. Microsc. Res. Tech., 76:988–991, 2013. © 2013 Wiley Periodicals, Inc.
Nanoscale elemental sensitivity study of Nd2Fe14B using absorption correlation tomography
Authors: Kao Thomas L. , Shi Crystal Y. , Wang Junyue , Mao Wendy L. , Liu Yijin , Yang Wenge 
Published: August 2013

ABSTRACTTransmission X‐ray microscopy (TXM) is a rapidly developing technique with the capability of nanoscale three dimensional (3D) real‐space imaging. Combined with the wide range in energy tunability from synchrotron sources, TXM enables the retrieval of 3D microstructural information with elemental/chemical sensitivity that would otherwise be inaccessible. The differential absorption contrast above and below absorption edges has been used to reconstruct the distributions of different elements, assuming the absorption edges of the interested elements are fairly well separated. Here we present an “Absorption Correlation Tomography” (ACT) method based on the correlation of the material absorption across multiple edges. ACT overcomes the significant limitation caused by overlapping absorption edges, significantly expands the capabilities of TXM, and makes it possible for fully quantitative nano‐scale 3D structural investigation with chemical/elemental sensitivity. The capability and robustness of this new methodology is demonstrated in a case study of an important type of rare earth magnet (Nd2Fe14B). Microsc. Res. Tech. 76:1112–1117, 2013. © 2013 Wiley Periodicals, Inc.
Burst‐swimming performance predicts the outcome of cannibalistic interactions in green poison frog larvae (Dendrobates auratus)
Authors: Wilcox Sean C. , Lappin A. Kristopher 
Published: August 2013

ABSTRACTWhole‐animal performance (e.g., swimming speed, bite force) functions as a fundamental link between organism and environment and, as such, performance characteristics are important in determining the outcomes of agonistic interactions, both interspecific and intraspecific. Cannibalism is an intraspecific agonistic interaction for which winners may be expected to exhibit superior performance in characteristics relevant to cannibalistic behavior. The larvae of the Green Poison Frog (Dendrobates auratus) exhibit cannibalistic behavior in which “fast‐starts” (i.e., high velocity and acceleration from a resting position) are used in attempts to bite and avoid being bitten by conspecifics. We tested the hypothesis that superior fast‐start swimming performance is positively associated with winning cannibalistic interactions between similarly sized individuals. Fast‐starts by larvae were imaged with a high‐speed camera, and pairs of size‐matched individuals then underwent interaction trials to determine whether swimming performance is associated with winning a cannibalistic interaction. Linear acceleration of the snout tip, approximating the position of the mouthparts used to attack an opponent, was significantly greater in winners than losers. At the estimated center of mass, generally representing a target for an attacking opponent, linear velocity and acceleration were significantly greater in winners than losers. Understanding the role of performance in intraspecific interactions can help elucidate how they contribute to population dynamics, and thus how such interactions ultimately drive morphological and behavioral evolution. J. Exp. Zool. 319A: 495–504, 2013. © 2013 Wiley Periodicals, Inc.
Effects of Copolymer Structure on the Mechanical Properties of Poly(dimethyl siloxane) Poly(oxamide) Segmented Copolymers
Authors: Buckwalter Daniel J. , Inglefield David L. , Enokida Joshua S. , Hudson Amanda G. , Moore Robert B. , Long Timothy E. 
Published: August 2013

An investigation of the structure–property relationships of poly(dimethyl siloxane) (PDMS) polyoxamide segmented copolymers reveals the impact of oxamide spacing and PDMS molecular weight on physical properties. Varying the length of the methylene spacing between the oxamide hydrogen bonding groups in the hard segment (HS), as well as the PDMS soft segment molecular weight, provides insight into the influence on thermal and mechanical properties. Bulk polycondensation of ethyl‐oxalate‐terminated PMDS oligomers with diamines yields optically clear, thermoplastic elastomers with excellent mechanical properties. The structure–property investigation reveals optimum mechanical properties of PDMS polyoxamide segmented copolymers occur with the smallest spacing between oxamide groups in the HS.
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A mutation in the promoter region of zipA, a component of the divisome, suppresses the shape defect of RodZ‐deficient cells
Authors: Shiomi Daisuke , Niki Hironori 
Published: August 2013

AbstractRodZ is important for maintaining the rod shape of Escherichia coli. Loss of RodZ causes conversion of the rod shape to a round shape and a growth rate slower than that of wild‐type cells. Suppressor mutations that simultaneously restore both the growth rates and the rod shape were isolated. Most of the suppressor mutations are found in mreB, mrdA, or mrdB. One of the mutations was in the promoter region of zipA, which encodes a crucial component of the cell division machinery. In this study, we investigated the mechanism of the suppression by this mutation. ZipA was slightly but significantly increased in the suppressor cells and led to a delay in cell division. While round‐shaped mreB and mrdA mutants lose cell bipolarity, we found that round‐shaped rodZ mutants retained cell bipolarity. Therefore, we concluded that a delay in the completion of septation provides extra time to elongate the cell laterally so that the zipA suppressor mutant is able to recover its ovoid or rod shape. The suppression by zipA demonstrates that the regulation of timing of septation potentially contributes to the conversion of morphology in bacterial cells.
Optimal therapy protocols in the mathematical model of acute leukemia with several phase constraints
Authors: Todorov Y. , Nuernberg F. 
Published: August 2013

SUMMARYA mathematical model for leukemia therapy based on the Gompertzian law of cell growth is investigated. The effect of the therapy is described in terms of therapy functions. Two types of therapy functions are considered: monotone and non‐monotone. In the first case, the effect of the chemotherapy on the normal cells directly depends on the quantity of the chemotherapeutic agent. In the second case, we consider a therapy function with a threshold effect, which influences the leukemia cells. This effect can describe resistance to the therapy. The optimal control problem has the purpose of minimizing the number of the leukemia cells subject to the constraints of the normal cells, whose number must not fall below a prescribed critical limit and of the amount of the chemotherapeutic agents in the body of the patient (i.e. constraint on the toxicity). Furthermore, a third phase constraint on the cumulative amount of the medicine over the whole therapy process is considered, which can be interpreted as an economic factor of the therapy. This optimization problem is solved analytically with the help of the Pontryagin's Maximum Principle, extension of penalty functions and additional analysis. Copyright © 2013 John Wiley & Sons, Ltd.
Phytochemical Study of the Alkaloidal Fractions of Unonopsis duckei R. E. Fr. Guided by Electrospray Ionisation Ion‐trap Tandem Mass Spectrometry
Authors: da Silva Felipe M. A. , de Souza Afonso D. L. , Koolen Hector H. F. , Barison Andersson , Vendramin Mayara E. , Costa Emmanoel V. , Ferreira Antonio G. , Pinheiro Maria Lúcia B. 
Published: August 2013

ABSTRACTIntroductionThe Unonopsis genus is a promising source of aporphinoid alkaloids, substances with great biological potential. These alkaloids have a well‐defined mass spectrometry fragmentation pattern that, together with previous phytochemical knowledge, can guide the isolation of alkaloids not yet described for the genus.ObjectiveIsolate substances not yet described in the Unonopsis genus, guided by alkaloidal profile analyses of stem barks, twigs and leaves of Unonopsis duckei using electrospray ionisation ion‐trap tandem mass spectrometry (ESI‐IT/MSn).MethodsMethanolic extracts from stem barks, twigs and leaves were submitted to a liquid–liquid, acid–base partitioning treatment to obtain the alkaloidal fractions. These fractions were analysed by direct infusion into an ESI‐IT/MSn system. The major alkaloids observed for each fraction were submitted to fragmentation analysis.ResultsThe MS fragmentation patterns revealed the presence of alkaloids previously reported for Annonaceae, including nornuciferine, anonaine, asimilobine, liriodenine and lysicamine, known for the Unonopsis genus, as well as others that were not yet described for this genus. In this way, the proaporphine alkaloid glaziovine was isolated, as well as a mixture of the aporphine alkaloids glaucine and norglaucine, all described for the first time in the Unonopsis genus.ConclusionMass spectrometry monitoring was fundamental to prioritise the isolation of substances not yet identified for the Unonopsis genus, dismissing known compounds and simplifying the phytochemical study. Copyright © 2013 John Wiley & Sons, Ltd.
Effect of Pt decoration on the gas response of ZnO nanoparticles
Authors: Daryakenari Ahmad Ahmadi , Apostoluk Aleksandra , Delaunay Jean‐Jacques 
Published: August 2013

AbstractIn order to improve the performance of gas sensors based on ZnO nanoparticles, platinum was deposited on the nanoparticle surface using sputtering. Gas‐sensing experiments on Pt‐functionalized ZnO nanoparticles exhibited larger response to ethanol gas at lower operating temperature, attributed to the sensitization and spillover effects. The faster recovery time of Pt‐decorated ZnO nanoparticles is associated with the catalyst effect of Pt. The maximum sensitivity of Pt‐decorated ZnO nanoparticles was more than twice compared to that of bare ZnO nanoparticles. At 400 °C, the response time of Pt‐decorated ZnO nanoparticles to 15 ppm ethanol vapor was 150 s, while that of bare ZnO nanoparticles was of about 1200 s. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Light emission from planar‐type ZnO p‐n junction fabricated by PLD
Authors: Kusumori Takeshi , Nakao Setsuo , Yoshimura Kazuki 
Published: August 2013

AbstractZinc oxide (ZnO) is a promising wide band‐gap semiconductor for optoelectronic devices such as high‐brightness (HB) light‐emitting‐diode (LEDs) in illumination applications. A significant difficulty has been the preparation of p‐type ZnO, which is indispensable for ZnO LEDs. We have prepared reproducible p‐type zinc oxide films by pulsed‐laser deposition (PLD) and a subsequent thermal annealing treatment. The Hall effect, with a Hall bar configuration, was measured in order to determine the conduction type of the films. The gradient of applied magnetic field vs. Hall voltage clearly implies the successful realization of p‐type ZnO films. After the confirmation of p‐type conductivity, the films were patterned again to prepare the planar‐type p‐n junction. Emission of visible light with bluish white color was observed when electrical current was injected through the junction. The spectra of the light indicate the emission start neat the band edge of ZnO. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
ZnO nanorod growth from aqueous solution via microwave heating on paper substrates
Authors: Ogata K. , Koike K. , Sasa S. , Inoue M. , Yano M. 
Published: August 2013

AbstractZnO nanorods were grown on paper substrates using aqueous solution at 95 °C by microwave heating. Although no direct growth on paper substrates was observed, surface coating with ZnMgO and Au layers enabled ZnO nanorod growth on paper substrates with rough surface structures of cellulose. X‐ray diffraction (XRD) measurements showed a weak diffraction peak from c‐axis oriented ZnO nanorods associated with tilted ones, which is related with not only rough surface structure of cellulose but also the poor properties of coated layers. In cathodoluminescence (CL) spectra, stronger bandedge emission was observed in ZnO nanorods on ZnMgO/paper in comparison of that on Au/paper substrates. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Sol‐gel undoped and Al‐doped ZnO films crystallized under an electric field and the ZnO/Si heterojunction characteristics
Authors: Abe Kazunori , Komiyama Takao , Chonan Yasunori , Yamaguchi Hiroyuki , Aoyama Takashi 
Published: August 2013

AbstractEffect of electric field on the crystallization of ZnO sol‐gel films was investigated by measuring x‐ray diffraction (XRD) patterns, photoluminescence (PL) spectra, and current‐voltage (I‐V) characteristics of n‐ZnO/p‐Si heterojunctions. When sol‐gel ZnO films (undoped and Al‐doped) were crystallized at 800 °C in air for 10 min, an electric field was applied between 0 and 2.0 kV/cm. As the electric field was increased, the XRD (002) peak intensity increased and had a maximum value at 1.5 and 2.0 kV/cm for the films on quartz and silicon substrates, respectively. The Hall carrier mobility increased and the carrier concentration decreased for the crystallized undoped and Al‐doped films when the electric field was 1.0 kV/cm and 1.5 kV/cm, respectively. As the electric field was increased from 0 to 2.0 kV/cm, the forward current increased and the reverse current decreased for n‐ZnO/p‐Si heterojunctions. These results indicated that application of electric fields was an effective means to reduce the defect density of ZnO sol‐gel films and to improve their heterojunction characteristics.
Characteristics of ZnO/CuO heterojunctions formed by direct bonding and PLD with bias voltage application
Authors: Komatsu Kazuya , Seno Yuki , Komiyama Takao , Chonan Yasunori , Yamaguchi Hiroyuki , Aoyama Takashi 
Published: August 2013

AbstractCurrent‐voltage (I–V) characteristics of the n‐ZnO/p‐CuO heterojunctions have been investigated by changing the composition of the ZnO films and by using the direct bonding technique to form the heterojunctions. A ZnO film was deposited on an n‐type ZnO ceramic substrate by the PLD technique with bias voltage application. The change of the PLD bias voltage caused the deviation from the stoichiometric condition for ZnO films and led to growth of different grain sizes. The n‐ZnO/ZnO specimens were directly bonded on p‐type CuO substrates at room temperature. Post annealing at 400 °C for 1 h improved the diode characteristic but more than about 3 h annealing deteriorated the I‐V characteristics. A deposition condition close to stoichiometric oxygen/zinc = 1 caused the largest activation energies for both the forward and the reverse currents while a slightly zinc‐rich condition caused a larger forward and a smaller reverse currents. This suggested the applicability of the direct bonding technique for fabricating excellent ZnO heterojunctions. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)