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Structure Consisting (structure + consisting)
Selected AbstractsHead regeneration in HydraDEVELOPMENTAL DYNAMICS, Issue 2 2003Hans R. Bode Abstract Hydra, a primitive metazoan, has a simple structure consisting of a head, body column, and foot aligned along a single oral,aboral axis. The body column has a high capacity for regeneration of both the head and foot. Because of the tissue dynamics that take place in adult Hydra, the processes governing axial patterning are continuously active to maintain the form of the animal. Regeneration in hydra is morphallactic and closely related to these axial patterning processes. As might be expected, analysis at the molecular level indicates that the same set of genes are involved in head regeneration and the maintenance of the head in the context of the tissue dynamics of the adult. The genes analyzed so far play roles in axial patterning processes in bilaterians. Developmental Dynamics 226:225,236, 2003. © 2003 Wiley-Liss, Inc. [source] Identification of genes involved in the biosynthesis of the cytotoxic compound glidobactin from a soil bacteriumENVIRONMENTAL MICROBIOLOGY, Issue 7 2007Barbara Schellenberg Summary Glidobactins (syn. cepafungins) are a family of structurally related cytotoxic compounds that were isolated from the soil bacterial strain K481-B101 (ATCC 53080; DSM 7029) originally assigned to Polyangium brachysporum and, independently, from an undefined species related to Burkholderia cepacia. Glidobactins are acylated tripeptide derivatives that contain a 12-membered ring structure consisting of the two unique non-proteinogenic amino acids erythro -4-hydroxy- l -lysine and 4(S)-amino-2(E)-pentenoic acid. Here we report the cloning and functional analysis of a gene cluster (glbA,glbH) involved in glidobactin synthesis from K481-B101, which according to its 16S rRNA sequence belongs to the Burkholderiales. The putative encoded proteins include a mixed non-ribosomal peptide/polyketide synthetase whose structure and architecture allowed to build a biosynthetic pathway model explaining the biosynthesis of the unique peptide part of glidobactins. Intriguingly, among the more than 600 bacterial strains whose genome sequence is currently available, homologous gene clusters were found in Burkholderia pseudomallei, the causing agent of melioidosis, and in the insect pathogen Photorhabdus luminescens, strongly suggesting that these organisms are capable to synthesize compounds similar to glidobactins. In addition, a glb gene cluster that was inactivated by transposon-mediated rearrangements was also present in Burkholderia mallei, a very close relative of B. pseudomallei and the causing agent of glanders in horse-like animals. [source] Synthesis and Characterization of Semiconductive Dichloridobis(thianthrene)gold(1+) Tetrachloridoaurate(1,)EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 17 2009Rachmat Triandi Tjahjanto Abstract A new (thianthrene)gold(III) complex has been synthesized in liquid SO2 as the solvent from thianthrene (TA) andAuCl3. [AuCl2(TA)2][AuCl4] [triclinic, P, a = 9.9832(2) Å, b = 10.3404(2) Å, c = 15.0798(4) Å, , = 75.038(1)°, , = 81.610(1)°, , = 68.409(1)°, V = 1396.15(5) Å3, Z = 2] has a salt-like structure consisting of [AuCl2(TA)2]+ and [AuCl4], ions, both with square-planar coordinated gold atoms of oxidation state +3. In the cation, two bent TA molecules are coordinated to Au each through one sulfur atom. The title compound is thermally stable up to 425 K and is semiconducting with a conductivity reaching 25 mSm,1 at 380 K and a low activation energy of 0.43 eV. A model for the charge transport along the stacked cationic complexes is discussed. When dissolved in chloroform [AuCl2(TA)2][AuCl4] is converted into the already known uncharged, mononuclear complex [AuCl3(TA)], which shows that a polymerization isomerism exists between the two forms.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Redox Modification of EMACs Through the Tuning of Ligands: Heptametal(II) Complexes of Pyrazine-Modulated Oligo-,-pyridylamido LigandsEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 14 2009Rayyat Huseyn Ismayilov Abstract Using pyrazine-modulated oligo-,-pyridylamido ligands N2 -(pyrazin-2-yl)- N6 -[6-(pyrazin-2-ylamino)pyridin-2-yl]pyridine-2,6-diamine (H3pzpz) and N2 -(pyrazin-2-yl)- N6 -[6-(pyridin-2-ylamino)pyridin-2-yl]pyridine-2,6-diamine (H3tpz), linear heptametal(II) extended metal atom chains (EMACs) [M7(,7 -L)4X2] [L = pzpz3,, M = NiII, X = Cl, (1), NCS, (2); M = CrII, X = Cl, (3), NCS, (4); L = tpz3,, M = CrII, X = Cl, (5), NCS, (6)] were synthesized and structurally characterized. Electrochemical studies showed that heptanickel(II) complexes can undergo one reversible oxidation at +0.46 V for 1 and +0.52 V for 2. Chromium(II) species 3 exhibited two reversible, one-electron oxidation peaks at +0.61 and +0.88 V, and 5 exhibited three reversible, one-electron oxidation peaks at +0.40, +0.68 and +1.07 V. The redox peaks shifted positively when axial ligands changed from chloride to thiocyanate anions, at +0.67 and +0.92 V for 4 and +0.44, +0.73 and +1.11 V for 6. The introduction of electron-withdrawing pyrazine rings to the spacer ligand retarded oxidation of the heptametal EMACs and stabilized the complexes. In nickel(II) species 1 and 2, both terminal nickel atoms exist in spin state S = 1 whereas all the inner nickel atoms exist in spin state S = 0. Temperature-dependent magnetic research revealed an antiferromagnetic interaction between the two terminal atoms through a superexchange pathway along metal cores with a parameter of about,4 cm,1. Chromium(II) species 3,6 showed a localized structure consisting of three quadruple Cr,Cr bonds and a single terminal CrII atom. Magnetic study revealed a quintet ground state resulting from the isolated, high-spin CrII atom.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Integration of a Rib Waveguide Distributed Feedback Structure into a Light-Emitting Polymer Field-Effect TransistorADVANCED FUNCTIONAL MATERIALS, Issue 9 2009Michael C. Gwinner Abstract Ambipolar light-emitting organic field-effect transistors (LEFETs) possess the ability to efficiently emit light due to charge recombination in the channel. Since the emission can be made to occur far from the metal electrodes, the LEFET structure has been proposed as a potential architecture for electrically pumped organic lasers. Here, a rib waveguide distributed feedback structure consisting of tantalum pentoxide (Ta2O5) integrated within the channel of a top gate/bottom contact LEFET based on poly(9,9-dioctylfluorene- alt -benzothiadiazole) (F8BT) is demonstrated. The emitted light is coupled efficiently into the resonant mode of the DFB waveguide when the recombination zone of the LEFET is placed directly above the waveguide ridge. This architecture provides strong mode confinement in two dimensions. Mode simulations are used to optimize the dielectric thickness and gate electrode material. It is shown that electrode absorption losses within the device can be eliminated and that the lasing threshold for optical pumping of the LEFET structure with all electrodes (4.5,µJ cm,2) is as low as that of reference devices without electrodes. These results enable quantitative judgement of the prospects for realizing an electrically pumped organic laser based on ambipolar LEFETs. The proposed device provides a powerful, low-loss architecture for integrating high-performance ambipolar organic semiconductor materials into electrically pumped lasing structures. [source] Simple Patterning via Adhesion between a Buffered-Oxide Etchant-Treated PDMS Stamp and a SiO2 Substrate,ADVANCED FUNCTIONAL MATERIALS, Issue 13 2007Y.-K. Kim Abstract A very simple polydimethylsiloxane (PDMS) pattern-transfer method is devised, called buffered-oxide etchant (BOE) printing. The mechanism of pattern transfer is investigated, by considering the strong adhesion between the BOE-treated PDMS and the SiO2 substrate. PDMS patterns from a few micrometers to sub-micrometer size are transferred to the SiO2 substrate by just pressing a stamp that has been immersed in BOE solution for a few minutes. The patterned PDMS layers work as perfect physical and chemical passivation layers in the fabrication of metal electrodes and V2O5 nanowire channels, respectively. Interestingly, a second stamping of the BOE-treated PDMS on the SiO2 substrate pre-patterned with metal as well as PDMS results in a selective transfer of the PDMS patterns only to the bare SiO2. In this way, the fabrication of a device structure consisting of two Au electrodes and V2O5 nanowire network channels is possible; non-ohmic semiconducting I,V characteristics, which can be modeled by serially connected percolation, are observed. [source] A simulation model for design and evaluation of micro-irrigation systemsIRRIGATION AND DRAINAGE, Issue 4 2001C.M.G. Pedras goutteurs; micro-aspersion; modèle AVALOC; analyse des performances Abstract The rational use and conservation of water resources require that irrigation performance, including emission uniformity, be as high as possible. Simulation models can help achieve these objectives. The AVALOC model has been developed for design and performance analysis of microirrigation systems, adopting the sector as the unit for analysis. The model works with the Windows operating system and is explored interactively through a simple dialogue structure consisting of a sequence of user-friendly interfaces. Model computations are supported by a database containing updated information on the emitters and pipes available on the market, and where the information relative to the sectors being designed or evaluated is stored. The databases allow easy introduction, visualization and correction of data through a user-friendly menu. In the design mode, the model provides for the selection of pipes and emitters that permit the attainment of the target performance, including emitter discharge uniformity. In the performance analysis mode, a hydraulics simulation is executed and several system performance parameters are then computed. The simulation can be performed using data created during design or data collected from field system evaluation. The present paper describes the main features of the model and shows a design example applied to an olive orchard. Copyright © 2001 John Wiley & Sons, Ltd. L'utilisation rationnelle des ressources en eau et la conservation des ressources naturelles requiert que les performances des systèmes d'irrigation soient les plus hautes que possible. L'utilisation des modèles de simulation pour le projet et l'évaluation des systèmes de microirrigation peut aider à atteindre un tel objectif. Ainsi, le modèle AVALOC a été développé pour le projet de ces systèmes et aussi pour leur analyse de performance. Le modèle utilise le language Visual Basic pour le système opératif Windows et il est exploré à travers d'un ensemble d'interfaces de dialogue avec l'utilisateur. L'unité d'analyse est le secteur d'irrigation. Les calculs font appel à une base de données contenant de l'information actualisée sur les caractéristiques des émisseurs , gouteurs et microasperseurs , et des conduites disponibles sur le marché et où l'on emmagasine l'information relative aux secteurs en cours de projet ou d'évaluation. Les bases de données sont accedées par une interface de dialogue qui permet l'introduction, visualisation ou correction des données. Le mode de projet permet la selection des emisseurs et tuyaux qui donnent satisfaction aux objectfs de performance fixés à priori. La simulation du fonctionnement hydraulique du secteur en projet permet le calcul de plusieurs indicateurs de performance et, donc, de vérifier si la solution considérée doit être retenue ou modifiée, le modèle étant utilisé de façon interactive. Le mode de simulation hydraulique est aussi utilisé avec des données de terrain pour évaluer la performance des systèmes en operation. Cet article décrit les caractéristiques principales du modèle en même temps qu'on présente un exemple d'application à un système de goutte à goutte pour un olivier. Copyright © 2001 John Wiley & Sons, Ltd. [source] Crimp morphology in relaxed and stretched rat Achilles tendonJOURNAL OF ANATOMY, Issue 1 2007Marco Franchi Abstract Fibrous extracellular matrix of tendon is considered to be an inextensible anatomical structure consisting of type I collagen fibrils arranged in parallel bundles. Under polarized light microscopy the collagen fibre bundles appear crimped with alternating dark and light transverse bands. This study describes the ultrastructure of the collagen fibrils in crimps of both relaxed and in vivo stretched rat Achilles tendon. Under polarized light microscopy crimps of relaxed Achilles tendons appear as isosceles or scalene triangles of different size. Tendon crimps observed via SEM and TEM show the single collagen fibrils that suddenly change their direction containing knots. The fibrils appear partially squeezed in the knots, bent on the same plane like bayonets, or twisted and bent. Moreover some of them lose their D-period, revealing their microfibrillar component. These particular aspects of collagen fibrils inside each tendon crimp have been termed ,fibrillar crimps' and may fulfil the same functional role. When tendon is physiologically stretched in vivo the tendon crimps decrease in number (46.7%) (P < 0.01) and appear more flattened with an increase in the crimp top angle (165° in stretched tendons vs. 148° in relaxed tendons, P < 0.005). Under SEM and TEM, the ,fibrillar crimps' are still present, never losing their structural identity in straightened collagen fibril bundles of stretched tendons even where tendon crimps are not detectable. These data suggest that the ,fibrillar crimp' may be the true structural component of the tendon crimp acting as a shock absorber during physiological stretching of Achilles tendon. [source] Morphological study of Czochralski-grown lanthanide orthovanadate single crystals and implications on the mechanism of bulk spiral formationJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 2 2010Hengjiang Cong Single crystals of monoclinic Nd:LaVO4 with dimensions up to Ø28 × 21,mm have been grown from the near-stoichiometric melt by the Czochralski method, making use of various seed orientations that are perpendicular to the (010), (10), (001) and (00) crystal planes. A sample was also prepared with the seed orientation in an arbitrary direction relative to the crystal. The anisotropic properties of the crystal are manifested in the growth morphology of the as-grown crystals, where different degrees of bulk spiral growth were observed. It was also found that employing the (001) or (00) seed faces severely suppressed the bulk spiral growth, and thus high quality and large-scale Nd:LaVO4 crystals were obtained. The constituent segregation coefficients and high-temperature stability, including the melting point, were determined and evaluated. Based on the attachment energy model of Hartman,Perdok theory, morphology predictions were made for monoclinic LaVO4 and tetragonal YVO4 orthovanadate single crystals. Correlating with the as-grown morphology of both crystals developed along different seed orientations, a theoretical explanation is provided for the influences of seed crystals on bulk spiral formation, crystal quality and utilization ratio. It suggests that breaking the axial symmetry of the ideal atomic level interface between crystal and melt plays a crucial triggering role in bulk spiral formation in the Czochralski growth of lanthanide orthovanadate single crystals. Selecting a proper seed orientation that yields such a highly axially symmetric surface structure consisting of a series of large-area facets with similar growth velocities can greatly reduce bulk spiral formation and thus is preferable in the Czochralski growth of large-sized low-symmetry oxide crystals. [source] Polymerization of 1,2:5,6-diepithio-3,4-di- O -methyl- D -mannitol, 1,2:5,6-diepithio-3,4-di- O -methyl- L -iditol, and 1,2:5,6-diepithio-3,4-di- O -methyl-allitol using zinc complexes: The regio- and stereoselectivities and asymmetric synthesis of thiosugar polymersJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 18 2005Toshifumi Satoh Abstract The polymerizations of the diepisulfides 1,2:5,6-diepithio-3,4-di- O -methyl- D -mannitol (1a), 1,2:5,6-diepithio-3,4-di- O -methyl- L -iditol (1b), and 1,2:5,6-diepithio-3,4-di- O -methyl-allitol (1c) were carried out with ZnEt2/H2O, ZnEt2/alcohol, and ZnEt2/(S or R)-1,1,-bi-2-naphthol (BN) as the initiator systems. All the polymerizations proceeded without any gel formation and gave white, powdery products. The number-average molecular weights of the obtained polymers were changed in the range of 5300,33,600. The polymerization of 1a using the ZnEt2/H2O (1/1) catalyst in tetrahydrofuran proceeded through a regio- and stereoselective cyclopolymerization mechanism to produce thiosugar polymers mainly consisting of 2,5-anhydro-1,5-dithio- D -glucitol as the five-membered ring units. The polymers obtained from 1b and 1c with ZnEt2/H2O exhibited lower stereoregularities than that from 1a. For the polymers obtained from 1a with the ZnEt2/alcohol systems, the molar fraction of the five-membered ring units depended on the alcohol used as a ligand. On the other hand, the polymerization of 1c using ZnEt2/(R or S)-BN asymmetrically proceeded, and optically active polymers consisting of desulfurized acyclic units were obtained. When ZnEt2/(R)-BN (1/1) was used in toluene, the polymer with [,]D23 = +56.9° was obtained in an 88.6% yield. The resulting polymer had an isotactic-rich structure consisting of about 90% (R)-configurational units and about 10% (S)-units. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4118,4125, 2005 [source] Dynamic boundary stabilization of a Reissner,Mindlin plate with Timoshenko beamMATHEMATICAL METHODS IN THE APPLIED SCIENCES, Issue 11 2004Marié Grobbelaar-Van Dalsen Abstract This paper is concerned with well-posedness results for a mathematical model for the transversal vibrations of a two-dimensional hybrid elastic structure consisting of a rectangular Reissner,Mindlin plate with a Timoshenko beam attached to its free edge. The model incorporates linear dynamic feedback controls along the interface between the plate and the beam. Classical semigroup methods are employed to show the unique solvability of the coupled initial-boundary-value problem. We also show that the energy associated with the system exhibits the property of strong stability. Copyright © 2004 John Wiley & Sons, Ltd. [source] Uniform stabilization of a one-dimensional hybrid thermo-elastic structureMATHEMATICAL METHODS IN THE APPLIED SCIENCES, Issue 14 2003Marié Grobbelaar-Van Dalsen Abstract This paper is concerned with the stabilization of a one-dimensional hybrid thermo-elastic structure consisting of an extensible thermo-elastic beam which is hinged at one end with a rigid body attached to its free end. The model takes account of the effect of stretching on bending and rotational inertia. The property of uniform stability of the energy associated with the model is asserted by constructing an appropriate Lyapunov functional for an abstract second order evolution problem. Critical use is made of a multiplier of an operator theoretic nature, which involves the fractional power A,1/2 of the bi-harmonic operator pair A acting in the abstract evolution problem. An explicit decay rate of the energy is obtained. Copyright © 2003 John Wiley & Sons, Ltd. [source] Explicit formulas for obtaining the radiation characteristics of an antenna based on a three-dimensional metallic photonic bandgap structureMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 6 2001Sailing He Abstract An antenna based on a three-dimensional metallic photonic bandgap (MPBG) structure consisting of many parallel metallic short wires is considered. An explicit method is introduced to calculate the radiation pattern for such an antenna system. The explicit method is verified numerically by comparing the results obtained by the finite-difference time-domain method. The present method improves the computation speed significantly. A genetic algorithm is used to make an optimal design for such a 3-D MPBG structure-based antenna. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 29: 376,381, 2001. [source] A shared promoter region suggests a common ancestor for the human VCX/Y, SPANX, and CSAG gene families and the murine CYPT familyMOLECULAR REPRODUCTION & DEVELOPMENT, Issue 2 2008Martin A. Hansen Abstract Many testis-specific genes from the sex chromosomes are subject to rapid evolution, which can make it difficult to identify murine genes in the human genome. The murine CYPT gene family includes 15 members, but orthologs were undetectable in the human genome. However, using refined homology search, sequences corresponding to the shared promoter region of the CYPT family were identified at 39 loci. Most loci were located immediately upstream of genes belonging to the VCX/Y, SPANX, or CSAG gene families. Sequence comparison of the loci revealed a conserved CYPT promoter-like (CPL) element featuring TATA and CCAAT boxes. The expression of members of the three families harboring the CPL resembled the murine expression of the CYPT family, with weak expression in late pachytene spermatocytes and predominant expression in spermatids, but some genes were also weakly expressed in somatic cells and in other germ cell types. The genomic regions harboring the gene families were rich in direct and inverted segmental duplications (SD), which may facilitate gene conversion and rapid evolution. The conserved CPL and the common expression profiles suggest that the human VCX/Y, SPANX, and CSAG2 gene families together with the murine SPANX gene and the CYPT family may share a common ancestor. Finally, we present evidence that VCX/Y and SPANX may be paralogs with a similar protein structure consisting of C terminal acidic repeats of variable lengths. Mol. Reprod. Dev. 75: 219,229, 2008. © 2007 Wiley-Liss, Inc. [source] Fabrication and properties of InSb films with ion-beam sputtering for use in the amplification of magneto-surface-acoustic wavesPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 8 2004N. Obata Abstract The magnetic surface acoustic wave (MSAW) device can be manipulated by an external magnetic field. However the MSAW is attenuated largely at high frequencies above MHz. Therefore, we proposed a MSAW device having a hybrid structure consisting of FeB amorphous thin film/InSb semiconductor thin film/LiNbO3 substrate. This device is utilized for amplification of surface acoustic waves by the interaction between surface acoustic waves and the carriers in the InSb semiconductor. We prepared (111) InSb thin films by ion beam sputtering. We obtained InSb thin films having Hall mobilities of about 2000 cm2/Vs by subsequent annealing. This showed the possibility of MSAW amplification by low voltages. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] 340,350 nm GaN-free UV-LEDsPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 1 2003T. Nishida Abstract Light extraction from AlGaN-based ultraviolet light emitting diodes (UV-LEDs) is described. The device structure is free from a GaN binary layer for the suppression of the reabsorption of the UV emission in the GaN layer. The UV extraction becomes six times higher when compared with that of the normal structure consisting of a GaN buffer layer. The highest external quantum efficiencies of 350- and 340-nm LEDs are 2.2 and 1.7%, respectively. The maximum output powers are 8.6 and 5.5 mW at injection currents of less than 150 mA. We also investigated the potential of combining the 350-nm UV-LED with a mixture of plural fluorescence materials for the application field of lighting. This combination can provide ideal lighting equipment that offers high colour rendering, steady colour, and no glare even with changes of intensity and illumination angle. (© 2003 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] High-energy vibrational modes in nitrogen-doped ZnOPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 3 2005U. Haboeck Abstract We present results of Raman-scattering experiments on a series of nitrogen-doped ZnO epilayers grown by chemical vapor deposition. Nitrogen, a potential acceptor in ZnO, was introduced by the thermal decomposition of ammonia (NH3). We found a structure consisting of at least four lines with frequencies of 2253, 2277, 2291, and 2304 cm,1. They increase in intensity simultaneously with additional modes in the energy range of the host phonons: both scale with the nitrogen concentration in the samples. The origin of the high-energy structure is tentatively assigned to vibrations of lattice-bound nitrogen or complexes, composed of the constituents of the dopant NH3. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Fabrication of field emitters using GaN particlesPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 7-8 2010Yuichiro Minakuchi Abstract The field emission from GaN particles has been demonstrated successfully for the first time. The novel field emitting device has a simple structure consisting of an electrically conductive polymer layer and GaN particles spread randomly on it. The GaN particles used for this device, which were synthesized in advance by the two-stage vapor phase method, have vertices and ridges formed by well-developed crystal planes. The electron emission started at an electric field of about 20 V/,m, and the current reached 10 nA at 28 V/,m. The maximum current density was 0.26 mA/cm2at 43 V/,m. The Fowler-Nordheim (F-N) plot of the I - V data indicated that the observed electron emission is originated from the F-N tunneling. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Spontaneous emission from semiconductor nanocrystals in coupled spherical microcavitiesPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 2 2005Yu. P. Rakovich Abstract We report on the coherent coupling of whispering gallery modes (WGM) in a photonic molecule formed from two melamine-formaldehyde spherical microcavities coated with a thin shell of light-emitting CdTe nanocrystals (NCs). Utilizing different excitation conditions the splitting of the WGM resonances originating from bonding and anti-bonding branches of the photonic states is observed and fine structure consisting of very sharp peaks resulting from lifting of the WGM degeneracy has been detected. Time-resolved measurements showed a slight increase in the spontaneous emission rate of NCs in a photonic molecule when compared to the spontaneous emission rate for NCs coating a single microsphere. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Exploration of the morphological transition phenomenon of polyaniline from microspheres to nanotubes in acid-free aqueous 1-propanol solution in a single polymerization processPOLYMER INTERNATIONAL, Issue 9 2010Yu-Fong Huang Abstract Polyaniline micro- or nanostructures have been widely investigated due to their unique physical and chemical properties. Although several studies have reported the synthesis of polyaniline microspheres and nanotubes, their mechanisms of formation remain controversial. This study reports our observation of the morphological transition of polyaniline from microspheres to nanotubes in a single polymerization process and also tries to propose their mechanisms of formation. The polymerization of aniline monomer in acid-free aqueous 1-propanol solutions (1 and 2 mol L,1) produces polyaniline microspheres and nanotubes at different reaction stages through a morphology transition process with treatment using ultrasound. In the initial reaction stage, Fourier transform infrared spectra indicate that the aniline monomers form phenazine-like units, producing polyaniline microspheres with an outside diameter of 1,2 µm. The hydrogen bonds between 1-propanol and polyaniline serve as the driving force for the polyaniline chains to build microspheres. As the reaction continues, observation indicates the microspheres decompose and reform one-dimensional nanotubes. In this stage, a structure consisting of a head of phenazine-like units and a tail of acid-doping para -linked aniline units develops. The protonation of the para -linked aniline units provides the driving force for the formation of nanotubes through a self-curling process. We report here the unique morphology transition of polyaniline from microspheres to nanotubes in a single polymerization process. The results indicate that the structural change of polyaniline leads to this morphological change. The mechanisms of formation of the microspheres and nanotubes in a polymerization process are also well explained. Copyright © 2010 Society of Chemical Industry [source] Perturbation signal design for neural network based identification of multivariable nonlinear systemsTHE CANADIAN JOURNAL OF CHEMICAL ENGINEERING, Issue 1 2002Pankaj S. Kulkarni Abstract The paper focuses on issues in experimental design for identification of nonlinear multivariable systems. Perturbation signal design is analyzed for a hybrid model structure consisting of linear and neural network structures. Input signals, designed to minimize the effects of nonlinearities during the linear model identification for the multivariable case, have been proposed and its properties have been theoretically established. The superiority of the proposed perturbation signal and the hybrid model has been demonstrated through extensive cross validations. The utility of the obtained models for control has also been proved through a case study involving MPC of a nonlinear multivariable neutralization plant. On traite dans cet article de la problématique des plans expérimentaux pour la détermination des systèmes multivariés non linéaires. La conception des signaux de perturbation est analysée pour un modèle de structure hybride composée de structures à réseaux linéaires et neuronaux. Des signaux d'entrée, con,us pour minimiser les effets des non-linéarités lors de la détermination du modèle linéaire pour le cas multivarié, sont proposés et leurs propriétés sont établies de manière théorique. La supériorité du signal de perturbation et du modèle hybride proposés est démontrée par des validations croisées poussées. L'utilité des modèles obtenus pour le contr,le est également prouvée par une étude de cas faisant intervenir le MPC d'une installation de neutralisation multivariée non linéaires. [source] The fourth level of social structure in a multi-level society: ecological and social functions of clans in hamadryas baboonsAMERICAN JOURNAL OF PRIMATOLOGY, Issue 11 2009Amy L. Schreier Abstract Hamadryas baboons are known for their complex, multi-level social structure consisting of troops, bands, and one-male units (OMUs) [Kummer, 1968. Social organization of hamadryas baboons. Chicago: The University of Chicago Press. 189p]. Abegglen [1984. On socialization in hamadryas baboons: a field study. Lewisburg, PA: Bucknell University Press. 207p.] observed a fourth level of social structure comprising several OMUs that rested near one another on sleeping cliffs, traveled most closely together during daily foraging, and sometimes traveled as subgroups independently from the rest of the band. Abegglen called these associations "clans" and suggested that they consisted of related males. Here we confirm the existence of clans in a second wild hamadryas population, a band of about 200 baboons at the Filoha site in lowland Ethiopia. During all-day follows from December 1997 through September 1998 and March 2005 through February 2006, data were collected on activity patterns, social interactions, nearest neighbors, band fissions, and takeovers. Association indices were computed for each dyad of leader males, and results of cluster analyses indicated that in each of the two observation periods this band comprised two large clans ranging in size from 7 to 13 OMUs. All band fissions occurred along clan lines, and most takeovers involved the transfer of females within the same clan. Our results support the notion that clans provide an additional level of flexibility to deal with the sparse distribution of resources in hamadryas habitats. The large clan sizes at Filoha may simply be the largest size that the band can split into and still obtain enough food during periods of food scarcity. Our results also suggest that both male and female relationships play a role in the social cohesion of clans and that males exchange females within clans but not between them. Am. J. Primatol. 71:948,955, 2009. © 2009 Wiley-Liss, Inc. [source] Daimonic elements in early traumaTHE JOURNAL OF ANALYTICAL PSYCHOLOGY, Issue 2 2003Donald E. Kalsched Abstract: This paper explores some of the ,daimonic' elements of unconscious mentation that emerge both in dreams and in the transference/countertransference field with early-trauma patients and illustrates these with an extended clinical example. An archaic and typical (archetypal) ,trauma complex' is articulated (with diagram) as a bi-polar structure consisting of divine child protected and/or persecuted by an inner ,guardian angel'. Sources of this structure and its mythological inner objects are traced to trauma at the stage of what Winnicott calls ,unintegration' and to flooding by disintegration anxiety at a time before nascent ego-structure has formed. In an extended case example, the author shows how the patient's traumatized innocence and desire for a new start, thwarted by self-attacking defences, pulls him into playing the inflated role of her guardian angel, leading to re-traumatization in the transference. Working through is seen as the necessary disillusionment and humanization of these daimonic structures as they are projected, suffered, and transmuted by the analytic partners in the stormy process of psychotherapy. [source] Superspace description of the homologous series Ga2O3(ZnO)mACTA CRYSTALLOGRAPHICA SECTION B, Issue 2 2010Yuichi Michiue A unified description for the structures of the homologous series Ga2O3(ZnO)m, gallium zinc oxide, is presented using the superspace formalism. The structures were treated as a compositely modulated structure consisting of two subsystems. One is constructed with metal ions and the other with O ions. The ideal model is given, in which the displacive modulations of ions are well described by the zigzag function with large amplitudes. Alternative settings are also proposed which are analogous to the so-called modular structures. The validity of the model has been confirmed by refinements for phases with m = 6 and m = 9 in the homologous series. A few complex phenomena in real structures are taken into account by modifying the ideal model. [source] Interactions between dimers of {1,1,-[o -phenylenebis(nitrilomethylidyne)]di-2-naphtholato-,4O,N,N,,O,}nickel(II)ACTA CRYSTALLOGRAPHICA SECTION C, Issue 12 2009Anita Blagus In the title compound, [Ni(C28H18N2O2)], the NiII centre has a square-planar coordination geometry in which the Schiff base ligand acts as a cis - O,N,N,,O,-tetradentate ligand. The crystal structure is built up of centrosymmetric dimer units stacked into chains along the [010] direction. Adjacent chains associate via C,H...O hydrogen bonding only, leading to a two-dimensional sheet-like structure consisting of layers parallel to (10). The cofacial dimeric complex contains an Ni...Ni contact of 3.291,(4),Å. [source] Potassium silver tin selenide, K2Ag2Sn2Se6ACTA CRYSTALLOGRAPHICA SECTION C, Issue 11 2001Jing Li The title compound was synthesized by a reactive salt reaction at 773,K over a period of 5,d. It has a one-dimensional chain structure consisting of K+ cations and one-dimensional [Ag2Sn2Se6]2, anions. The chain is constructed by edge-sharing bitetrahedral [Sn2Se6] units connected in a 1:2 ratio via linear Ag+ ions. [source] A description of the structural determination procedures of a gap junction channel at 3.5,Å resolutionACTA CRYSTALLOGRAPHICA SECTION D, Issue 8 2009Michihiro Suga Intercellular signalling is an essential characteristic of multicellular organisms. Gap junctions, which consist of arrays of intercellular channels, permit the exchange of ions and small molecules between adjacent cells. Here, the structural determination of a gap junction channel composed of connexin 26 (Cx26) at 3.5,Å resolution is described. During each step of the purification process, the protein was examined using electron microscopy and/or dynamic light scattering. Dehydration of the crystals improved the resolution limits. Phase refinement using multi-crystal averaging in conjunction with noncrystallographic symmetry averaging based on strictly determined noncrystallographic symmetry operators resulted in an electron-density map for model building. The amino-acid sequence of a protomer structure consisting of the amino-terminal helix, four transmembrane helices and two extracellular loops was assigned to the electron-density map. The amino-acid assignment was confirmed using six selenomethionine (SeMet) sites in the difference Fourier map of the SeMet derivative and three intramolecular disulfide bonds in the anomalous difference Fourier map of the native crystal. [source] Preparation and preliminary X-ray analysis of the catalytic module of ,-1,3-xylanase from the marine bacterium Vibrio sp.ACTA CRYSTALLOGRAPHICA SECTION D, Issue 8 2004,-1,3-xylanase (1,3-,- d -xylan xylanohydrolase; EC 3.2.1.32) is an enzyme capable of hydrolyzing ,-1,3-xylan. The newly cloned ,-1,3-xylanase from the marine bacterium Vibrio sp. AX-4 (XYL4) exhibited a modular structure consisting of three modules: an N-terminal catalytic module belonging to glycoside hydrolase family 26 and two C-terminal xylan-binding modules belonging to carbohydrate-binding module family 31. Despite substantial crystallization screening, crystallization of the recombinant XYL4 was not accomplished. However, the deletion mutant of XYL4, composed of a catalytic module without a xylan-binding module, was crystallized. The crystal belonged to space group P212121, with unit-cell parameters a = 51.6, b = 75.8, c = 82.0,Å. X-ray diffraction data were collected to 1.44,Å resolution. [source] Structure of EstA esterase from psychrotrophic Pseudoalteromonas sp.ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 9 2009643A covalently inhibited by monoethylphosphonate The crystal structure of the esterase EstA from the cold-adapted bacterium Pseudoalteromonas sp. 643A was determined in a covalently inhibited form at a resolution of 1.35,Å. The enzyme has a typical SGNH hydrolase structure consisting of a single domain containing a five-stranded ,-sheet, with three helices at the convex side and two helices at the concave side of the sheet, and is ornamented with a couple of very short helices at the domain edges. The active site is located in a groove and contains the classic catalytic triad of Ser, His and Asp. In the structure of the crystal soaked in diethyl p -nitrophenyl phosphate (DNP), the catalytic serine is covalently connected to a phosphonate moiety that clearly has only one ethyl group. This is the only example in the Protein Data Bank of a DNP-inhibited enzyme with covalently bound monoethylphosphate. [source] A cell leakproof PLGA-collagen hybrid scaffold for cartilage tissue engineeringBIOTECHNOLOGY PROGRESS, Issue 3 2010Naoki Kawazoe Abstract A cell leakproof porous poly(DL -lactic-co-glycolic acid) (PLGA)-collagen hybrid scaffold was prepared by wrapping the surfaces of a collagen sponge except the top surface for cell seeding with a bi-layered PLGA mesh. The PLGA-collagen hybrid scaffold had a structure consisting of a central collagen sponge formed inside a bi-layered PLGA mesh cup. The hybrid scaffold showed high mechanical strength. The cell seeding efficiency was 90.0% when human mesenchymal stem cells (MSCs) were seeded in the hybrid scaffold. The central collagen sponge provided enough space for cell loading and supported cell adhesion, while the bi-layered PLGA mesh cup protected against cell leakage and provided high mechanical strength for the collagen sponge to maintain its shape during cell culture. The MSCs in the hybrid scaffolds showed round cell morphology after 4 weeks culture in chondrogenic induction medium. Immunostaining demonstrated that type II collagen and cartilaginous proteoglycan were detected in the extracellular matrices. Gene expression analyses by real-time PCR showed that the genes encoding type II collagen, aggrecan, and SOX9 were upregulated. These results indicated that the MSCs differentiated and formed cartilage-like tissue when being cultured in the cell leakproof PLGA-collagen hybrid scaffold. The cell leakproof PLGA-collagen hybrid scaffolds should be useful for applications in cartilage tissue engineering. © 2009 American Institute of Chemical Engineers Biotechnol. 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