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Configuration
Kinds of Configuration Terms modified by Configuration Selected AbstractsINFLUENCE OF CAVITY CONFIGURATION ON MICROLEAKAGE AROUND CLASS V RESTORATIONS BONDED WITH SEVEN SELF-ETCHING ADHESIVESJOURNAL OF ESTHETIC AND RESTORATIVE DENTISTRY, Issue 2 2004Jorge Perdigão DMD [source] Architectural Methodology Based on Intentional Configuration of BehaviorsCOMPUTATIONAL INTELLIGENCE, Issue 1 2001François Michaud Intelligence has been an object of study for a long time. Different architectures try to capture and reproduce these aspects into artificial systems (or agents), but there is still no agreement on how to integrate them into a general framework. With this objective in mind, we propose an architectural methodology based on the idea of intentional configuration of behaviors. Behavior-producing modules are used as basic control components that are selected and modified dynamically according to the intentions of the agent. These intentions are influenced by the situation perceived, knowledge about the world, and internal variables that monitor the state of the agent. The architectural methodology preserves the emergence of functionality associated with the behavior-based paradigm in the more abstract levels involved in configuring the behaviors. Validation of this architecture is done using a simulated world for mobile robots, in which the agent must deal with various goals such as managing its energy and its well-being, finding targets, and acquiring knowledge about its environment. Fuzzy logic, a topologic map learning algorithm, and activation variables with a propagation mechanism are used to implement the architecture for this agent. [source] Coordinating components in middleware systemsCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 13 2003Matthias Radestock Abstract Configuration and coordination are central issues in the design and implementation of middleware systems and are one of the reasons why building such systems is more complex than constructing stand-alone sequential programs. Through configuration, the structure of the system is established,which elements it contains, where they are located and how they are interconnected. Coordination is concerned with the interaction of the various components,when an interaction takes place, which parties are involved, what protocols are followed. Its purpose is to coordinate the behaviour of the various components to meet the overall system specification. The open and adaptive nature of middleware systems makes the task of configuration and coordination particularly challenging. We propose a model that can operate in such an environment and enables the dynamic integration and coordination of components by observing and coercing their behaviour through the interception of the messages exchanged between them. Copyright © 2003 John Wiley & Sons, Ltd. [source] Configuration, conformation and crystal structure of rabdosianin bCRYSTAL RESEARCH AND TECHNOLOGY, Issue 8 2005Bao Lin Li Abstract Rabdosianin B, 7,20-epoxy-7,-hydroxy-1,,6,,11,,15,-tetraacetoxy- ent -kaur-16-ene, C28H38O10, was the first isolated from Isodon henryi. It consists of three six-membered rings A, B, C and one five-membered ring D. The fused-ring system A, B and C are in chair, boat and chair conformations, respectively, and ring D is in an envelope conformation, on the basis of NMR and X-ray diffraction analysis. The crystal of rabdosianin B is in orthorhombic crystal system with space group P212121, lattice constants: a = 9.969(1) Å, b = 15.400(3) Å, and c = 17.624(3) Å, Z = 4. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Assessing the habitat quality of oil mallees and other planted farmland vegetation with reference to natural woodlandECOLOGICAL MANAGEMENT & RESTORATION, Issue 3 2009F. Patrick Smith Summary, Much of the tree and shrub planting that has been conducted on farms in Western Australia over the past three decades has not been done with the specific intention of creating habitat or conserving biodiversity, particularly commercially oriented monocultures like oil mallee plantings. However, such plantings may nonetheless provide some habitat resources for native plants and animals. This study assessed the habitat quality of farm plantings (most of which were not planted with the primary intention of biodiversity conservation) at 72 sites across a study region in the central wheatbelt of Western Australia. Widely accepted habitat metrics were used to compare the habitat resources provided by planted farmland vegetation with those provided by remnant woodland on the same farms. The impact of adjacency of plantings to woodland and, in the case of oil mallees, the planting configuration on predicted habitat quality is assessed. Condition Benchmarks for five local native vegetation communities are proposed. Farmland plantings achieved an average Vegetation Condition Score (VCS) of 46 out of a possible 100, while remnant woodland on the same farms scored an average 72. The average scores for farm plantings ranged from 38,59 depending on which of five natural vegetation communities was used as its benchmark, but farm plantings always scored significantly less than remnant woodland (P < 0.001). Mixed species plantings on average were rated more highly than oil mallees (e.g. scores of 42 and 36 respectively using the Wandoo benchmark) and adjacency to remnant woodland improved the score for mixed plantings, but not for oil mallees. Configuration of oil mallees as blocks or belts (i.e. as an alley farming system) had no impact on the VCS. Planted farmland vegetation fell short of remnant woodland in both floristic richness (51 planted native species in total compared with a total of more than 166 naturally occurring plant species in woodland) and structural diversity (with height, multiple vegetation strata, tree hollows and woody debris all absent in the relatively young 7,15-year-old farm plantings). Nonetheless farmland plantings do have measurable habitat values and recruitment and apparent recolonization of plantings with native plant species was observed. Habitat values might be expected to increase as the plantings age. The VCS approach, including the application of locally relevant Benchmarks is considered to be valuable for assessing potential habitat quality in farmland vegetation, particularly as a tool for engaging landholders and natural resource management practitioners. [source] Metal-Directed Self-Assembly: Two New Metal-Binicotinate Grid Polymeric Networks and Their Fluorescence Emission Tuned by Ligand ConfigurationEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 13 2004Benlai Wu Abstract Two new 2-D metal-binicotinate coordination polymers, namely, [CdII(bpdc)]n (1) and {[ZnII8(bpdc)8(H2O)8](H2O)8}n (2) (H2bpdc = binicotinic acid) have been synthesized using hydrothermal and three-layer diffusion methods, respectively. Single-crystal X-ray analyses revealed that both are extended grid networks of the (4,4) topology. Their structures alter with the configuration and function of bpdc. The achiral, free H2bpdc has axial chirality induced by metal coordination in 1, and bpdc connects to four metal centers forming a 2-D (4,4) net with three kinds of apertures generated through self-assembly. In 2, however, bpdc connects to three metal centers, fabricating a microporous framework containing hydrophilic channels. Studies on the solid emission spectra of the free ligand, 1, and 2 confirmed, that the configuration of bpdc resulting from metal-directed coordination has a profound effect on the fluorescence emissions of 1 and 2. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] Configuration of Octahedral Metal Compounds , Equilibrium, Crystal and Molecular Structure of Nickel(II) Complexes of Linear N2O4, N4S2 or N6 Donors Set Atoms LigandsEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 6 2004Aminou Mohamadou Abstract Two new nickel(II) complexes of symmetric hexadentate mixed-ligand N,O [1,12-bis(2-pyridyl)-5,8-dioxa-2,11-diazadodecane (pydado)] and N,S [1,12-bis(2-pyridyl)-5,8-dithia-2,11-diazadodecane (pydadt)] donor atoms have been synthesised as perchlorate salts and characterised by X-ray crystallography and ligand-field spectroscopy. In both complexes the Ni2+ ion is hexacoordinate. The cation [Ni(pydado)]2+ is pseudo-octahedral with the two pyridyl groups in trans position; all Ni,N and Ni,O bond lengths are practically equivalent. In [Ni(pydadt)]2+ complex, however, the size of the thioether sulfur atoms imposes a C2v symmetry; the pyridyl groups and the sulfur atoms are in trans positions and all Ni,N bond lengths are equivalent. The comparison of these structures with those of octahedral cobalt, copper and zinc complexes with the same ligands shows that their configurations depend not only on the nature of the two central donor atoms of the ligand, but also on the nature of the metallic ion. In aqueous solution, the stability constants of the NiII chelates with these two ligands, determined by potentiometry, show the formation of [Ni(LH)]3+ and [NiL]2+ species in all cases. The chelating power of the pydadt ligand is slightly greater than that of pydado. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] Boron-Based Diastereomerism and Enantiomerism in Imine Complexes , Determination of the Absolute Configuration at Boron by CD SpectroscopyEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 31 2008Manfred Braun Abstract Boron turns out to be a stable stereogenic center in imine complexes of aryl and alkyl boronates. Diastereomerically pure complexes 7a,c are obtained from chiral imine ligands 5a,b that are derived from the amino alcohol (R)- 4. The configuration at the boron atom is determined by crystal structure analyses. Racemic boronates 10a,c, available from a condensation of aryl boronic acids 6 with the achiral imine ligand 9, can be separated into stable enantiomers by HPLC on a chiral column. The racemization barrier ,G, has been determined to amount to 105,115 kJ,mol,1. The comparison of calculated and measured CD spectra permits to assign unambiguously the absolute configuration to boron in the enantiomeric boronate-imine complex 10a.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Tetra- tert -butyltrioxabicyclo[3.3.1]nonadienedicarboxylic Acid: Optical Resolution, Absolute Configuration and Application in Chiral DiscriminationEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 19 2008Jennifer Kremsner Abstract The enantiopure bridged bis-dioxine 4, a dissymmetric dicarboxylic acid exhibiting axial chirality, can easily be synthesized and serve as host for separating and/or transporting chiral guest molecules. Racemic 4 gives with (R)- and (S)-1-phenylethylamine the corresponding pure diastereomeric salts 7 and 8. The absolut configuration of the diacid 4 in the diastereomeric salt 7 containing (R)-1-phenylethylamine was confirmed to be R by X-ray crystal structure analysis, which also confirmed its concave nature. Release of the acid-sensitive pure enantiomers (R)- 4 as well as (S)- 4 was achieved conveniently by use of dry flash-chromatography on silica. The CD spectrum shows a positive Cotton effect of the (S)-enantiomer at 206 nm. The enantiomeric purity was proved by 1H NMR discrimination of the diastereomeric salts with (R,R)-1,2-bis(4-methoxyphenyl)ethane-1,2-diamine as the base. The dicarboxylic acid (R)- 4 can be used as chiral auxiliary as demonstrated by the difficult resolution of racemicN,N,-di- tert -butyl-1,2-bis(4-methoxyphenyl)ethane-1,2-diamine 9.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Diels,Alder Reactions of Symmetrically 1,4-Disubstituted Dienes: Theoretical Study on the Influence of the Configuration of the Double Bonds on the Regio- and EndoselectivityEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 18 2008Samira Baki Abstract It was experimentally shown in Diels-Alder reactions that symmetrically 1,4-disubstituted dienes exhibit high regio- and endoselectivity induced by the (E,Z) configuration of the double bonds. In order to understand the origin of this selectivity, the transition states associated with the reaction between a series of such dienes (R = OMe, CH3, NH2, F, CN) on substituted ethylene (R, = CO2Me, CN, F, OMe) were determined by DFT calculations. If the regioselectivity confirmed by a single-point MP2 calculation is predicted to be good in most cases, its direction remains difficult to predict; the R, group of the dienophile can orient itself toward either the (Z) or the (E) side of the diene. Neither primary nor secondary frontier orbital interactions appear to be able to rationalize these results. They are more likely explained by a delicate balance between steric and electrostatic interactions. This hypothesis is further supported by the calculated reactivity of the (E,E) and (Z,Z) corresponding dienes. In any case, a standard DFT calculation, confirmed by a single-point MP2 step, is likely to provide a reliable guideline for a synthesis strategy that allows the control of up to four stereogenic centres in a single reaction step.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Synthesis and Absolute Configuration of (+)-Pseudodeflectusin: Structural Revision of Aspergione BEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 21 2006Fumiyo Saito Abstract We report herein the total synthesis and determination of the absolute configuration of (+)-pseudodeflectusin. The total synthesis of (+)-pseudodeflectusin starting from o -anisic aid was achieved in 11 total steps with an overall yield of 2.0,%. The 1H- and 13C NMR spectroscopic data of our synthetic pseudodeflectusin was identical to that of the natural compound. The absolute configuration of (+)-pseudodeflectusin was determined by chiral HPLC and X-ray crystallographic analyses. We also synthesized the proposed structure of aspergione B, whose 1H- and 13C NMR spectroscopic data is identical to that of pseudodeflectusin. The 1H- and 13C NMR spectra of our synthetic aspergione B were different from those of the natural compound reported by Proksch et al. Our results confirm that aspergione B and pseudodeflectusin are, in fact, the same compound.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] First Asymmetric Synthesis and Determination of the Absolute Configuration of a Lignan Isolated from Virola sebiferaEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 10 2005Dieter Enders Abstract The first asymmetric synthesis of a lignan isolated from the seeds of Virola sebifera, one of the most widely spread Myristicaceae species in Brazil, in four steps (48,% overall yield) and with excellent stereoselectivity (de, ee , 96,%) is described. The key step is the asymmetric Michael addition of a lithiated enantiopure ,-amino nitrile to an enone, followed by ,-methylation and cleavage of the amino nitrile. The absolute configuration of the naturally occurring 1,4-diketone was determined by polarimetry as well as by CD spectroscopy and quantum chemical calculations. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] ,N-Stereogenic Quaternary Ammonium Salts' from L -Amino Acids: Synthesis, Separation, and Absolute ConfigurationHELVETICA CHIMICA ACTA, Issue 4 2009Hua-Fang Wu Abstract Diastereoisomeric linear and cyclic ,N-chiral quaternary ammonium salts' (QASs) were efficiently synthesized from corresponding L -amino acids in high yields. The diastereoisomers of each pair of ,N-chiral QASs' were successfully separated. The absolute configurations of these QASs were determined predominately by X-ray single-crystal analysis. The 1H-NMR data of ,N-chiral QASs' provided characteristic information on the configuration of the N-chiral center. ,N-Chiral QASs' exemplified by [N(R)]- 2a and [N(S)]- 2a are stable in protic and aprotic solvents within a broad pH and temperature range. [source] Crystal Structure of Garciniaphenone and Evidences on the Relationship between Keto,Enol Tautomerism and ConfigurationHELVETICA CHIMICA ACTA, Issue 7 2008Felipe Abstract Garciniaphenone (=rel- (1R,5R,7R)-3-benzoyl-4-hydroxy-8,8-dimethyl-1,7-bis(3-methylbut-2-en-1-yl)bicyclo[3.3.1]non-3-ene-2,9-dione; 1), a novel natural product, was isolated from a hexane extract of Garcinia brasiliensis fruits. The crystal structure of 1 as well as the selected geometrical and configurational features were compared with those of known related polyprenylated benzophenones. Garciniaphenone is the first representative of polyprenylated benzophenones without a prenyl substituent at C(5). Notably, the absence of a 5-prenyl substituent has an impact on the molecular geometry. The tautomeric form of 1 in the solid state was readily established by a residual-electronic-density map generated by means of a difference Fourier analysis, and there is an entirely delocalized six-membered chelate ring encompassing the keto,enol moiety. The configuration at C(7) was used to rationalize the nature of the keto,enol tautomeric form within 1. The intermolecular array in the network is maintained by nonclassical intermolecular H-bonds. [source] Modeling the Effects of Reactor Inlet Configuration on Isothermal CVI Process of C/SiC CompositesINTERNATIONAL JOURNAL OF APPLIED CERAMIC TECHNOLOGY, Issue 6 2007Xi Wei Two comparative models were proposed to simulate the effects of the reactor configuration on the isothermal chemical vapor infiltration (ICVI) process of C/SiC composites. The difference in the two models is that there is an expansion zone near the reactor inlet in one model while no expansion zone exists in another model. Calculation results show that the existence of the expansion zone has rather negligible effects on the ICVI process. It is accordingly suggested that the simplification of the reactor configuration by neglecting the expansion zone of the reactor is reasonable and acceptable for the ICVI process of C/SiC composites. [source] UniFAFF: a unified framework for implementing autonomic fault management and failure detection for self-managing networksINTERNATIONAL JOURNAL OF NETWORK MANAGEMENT, Issue 4 2009Ranganai Chaparadza Today's network management, as known within the Fault, Configuration, Accounting, Performance, Security (FCAPS) management framework, is moving towards the definition and implementation of ,self-managing' network functions, with the aim of eliminating or drastically reducing human intervention in some of the complex aspects or daunting tasks of network management. The fault management plane of the FCAPS framework deals with the following functions: fault detection, fault diagnosis, localization or isolation, and fault removal. Task automation is at the very heart of self-managing (autonomic) nodes and networks, meaning that all functions and processes related to fault management must be automated as much as possible within the functionalities of self-managing (autonomic) nodes and networks, in order for us to talk about autonomic fault management. At this point in time there are projects calling for implementing new network architectures that are flexible to support on-demand functional composition for context- or situation-aware networking. A number of such projects have started, under the umbrella of the so-called clean-slate network designs. Therefore, this calls for open frameworks for implementing self-managing (autonomic) functions across each of the traditional FCAPS management planes. This paper presents a unified framework for implementing autonomic fault management and failure detection for self-managing networks, a framework we are calling UniFAFF. Copyright © 2008 John Wiley & Sons, Ltd. [source] Regioselective Reactions on a Chiral Substrate Controlled by the Configuration of a Chiral CatalystADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 2-3 2010Raju Ranjith Kumar Abstract A racemic mixture may be partially transformed in the presence of a chiral catalyst by kinetic resolution and formation of products with new structural features. If the starting material is fully consumed the products may still be enantiomerically enriched. The situation is summarized in the Introduction. A brief discussion on the regioselective transformations occurring on a racemic mixture under the influence of a chiral catalyst is presented in Section 2. Often stereo-differences occur, each enantiomer of the starting material resulting in a different product. It allows one to predict what the behaviour of some enantiopure substrates should be in presence of each of the enantiomers of a chiral catalyst. Many examples are presented in Section 3. The chiral substrates under consideration have two different reacting sites, usually of the same nature (OH, CC, allylic positions, CH for carbene insertion, epoxide fragment, etc.). In some cases the absolute configuration of the catalyst allows an excellent control of the regioselectivity. This approach is promising for the selective transformation of chiral molecules. [source] Free Right Internal Thoracic Artery in a "Horseshoe" Configuration: A New Technical Approach for "In Situ" Conduit LengtheningJOURNAL OF CARDIAC SURGERY, Issue 6 2005Jacob Zeitani M.D. We present a method to revascularize the left antero-lateral myocardial wall using the right internal thoracic artery as a "free graft" anastomosed side to end to the "in situ" left internal thoracic artery, in a "horseshoe" fashion. The two ends of the "free graft" were anastomosed to the left anterior descending coronary artery and the second obtuse marginal branch, respectively. This method was successfully used in a 74-year-old patient with severe chronic obstructive pulmonary disease. [source] Validation of a New Noninvasive Device for the Monitoring of Peak Endocardial Acceleration in Pigs: Implications for Optimization of Pacing Site and ConfigurationJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 7 2008PIERRE BORDACHAR M.D. Introduction: The peak of endocardial acceleration (PEA) is an index of myocardial contractility. We aimed to (1) demonstrate that the PEA measured by the noninvasive cutaneous precordial application of an accelerometer sensor is related to left ventricular (LV) dP/dt max and (2) assess the usefulness of PEA monitoring during graded ischemia and during different configurations of sequential biventricular pacing. Methods and Results: Measurements of invasive LV dP/dt max were compared with measurements of transcutaneous PEA in seven pigs at baseline and during acute drug infusions; increased heart rate; right, left, biventricular and sequential biventricular pacing before and after graded ischemia induced by the constriction of the left anterior descending coronary artery. A consistent PEA signal was obtained in all animals. PEA changes were highly related to LV dP/dt max changes (r= 0.93; P < 0.001). The changes of LV contractility induced by the different pacing configurations were detected by PEA analysis in the absence of ischemia (r= 0.94; P < 0.001) and in the presence of ischemic LV dysfunction (r= 0.91; P < 0.001). Conclusion: Noninvasive PEA measurement allows monitoring of left ventricular contractility and may be a useful tool to detect global effect of ventricular ischemia and to optimize the choice of both pacing site and pacing configuration. [source] Tournament Rituals, Category Dynamics, and Field Configuration: The Case of the Booker PrizeJOURNAL OF MANAGEMENT STUDIES, Issue 6 2008N. Anand abstract In this article we theorize the ways in which tournament rituals, in the form of prominent industry award ceremonies, configure organizational fields. We review field theory to distil four criteria to which field-configuring mechanisms should conform. We undertake an archival study of the Booker Prize for Fiction to explore how this tournament ritual has configured the field of contemporary English-language literature by championing the distinctive category of post-colonial fiction. [source] Resource Configuration in Family Firms: Linking Resources, Strategic Planning and Technological Opportunities to PerformanceJOURNAL OF MANAGEMENT STUDIES, Issue 1 2008Kimberly A. Eddleston abstract We apply the resource-based view of the firm to the study of family firms by investigating how a family specific resource (reciprocal altruism) and a firm specific resource (innovative capacity) contribute to family firm performance. We then examine how the impact of these resources is moderated by strategic planning and technological opportunities. Our findings suggest that family firms can benefit from emphasizing the positive aspects of kinship and from developing innovative capacities. As such, we demonstrate that not only do firm specific resources contribute to family firm performance, but also that family relationships can be a source of competitive advantage for a family firm. In addition, we found a heightened importance of reciprocal altruism in environments rich in technological opportunities, and that strategic planning is more important for those family firms that lack innovative capacities. [source] Configuration and racemization determination of cysteine residues in peptides by chiral derivatization and HPLC: application to oxytocin peptidesJOURNAL OF PEPTIDE SCIENCE, Issue 6 2001Sándor Szabó Abstract An improved RP-HPLC method was developed for the determination of the configuration and stereochemical purity of cysteine residues in peptides. The method consists of oxidation of cysteine and cystine residues to cysteic acid, followed by hydrolysis and pre-column chiral derivatization with Val-Marfey's reagent. Copyright © 2001 European Peptide Society and John Wiley & Sons, Ltd. [source] Design and Construction of Insulation Configuration for Ultra-High-Temperature Microwave Processing of CeramicsJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 12 2003Geng-fu Xu A multilayer insulation configuration suitable for microwave sintering of ceramics up to 2100°C was designed and tested successfully. The configuration is based on porous, granular BN/ZrO2 fiber composite powder for packed beds and spacer cylinders. This insulation allows stable, controlled microwave sintering and can be modified to microwave process materials with different thermal, dielectric properties with improved properties. [source] Effect of Sample Configuration on the Morphology of Foamed LDPE/PP Blends Injection Molded by a Gas Counterpressure ProcessMACROMOLECULAR MATERIALS & ENGINEERING, Issue 6 2007Georgi Kotzev Abstract Blends of isotactic poly(propylene) and low-density polyethylene with different composition ratios were prepared through direct melt compounding on a twin-screw extruder. The specimens with various geometric configurations were injection-molded using a gas counterpressure process, using blends to which 0.5 wt.-% of a blowing agent was added. The influence of blend composition and specimen geometry on the structure and morphology of the samples was investigated by SEM and WAXS. The thermal behavior of the blends was analyzed by DSC. It was found that the morphology of each region depended on the composition ratio and specimen geometry. [source] Configuration and conformation of a novel uridine analogue: 1H and 13C NMR spectra of (5'S)-1-[2'-(2-hydroxyethyl)tetrahydropyran-5'-yl]-1H -pyrimidine-2,4-dioneMAGNETIC RESONANCE IN CHEMISTRY, Issue 3 2002George Balayiannis Abstract A combination of homo- and heteronuclear 1D and 2D NMR techniques provided the assignment of the 1H and 13C resonances of the major component of a reaction product consisting of the two possible diastereomers of (5,S)-1-[2, -(2-hydroxyethyl)tetrahydropyran-5, -yl]-1H -pyrimidine-2,4-dione and showed that the tetrahydropyranyl ring in the major 5,S,2,S -isomer adopts the twist conformation. Copyright © 2002 John Wiley & Sons, Ltd. [source] Dark soliton generation using dual Brillouin fiber laser in a fiber optic ring resonatorMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 4 2010S. F. Hanim Abstract Stable dark soliton pulses have been successfully generated in an erbium doped dispersion compensated fiber (DCF) using an enhanced dual Brillouin fiber laser (DBFL) scheme.Multidark soliton pulses generation in an S-band erbium doped depressed cladding fiber (DC-EDF) using a multiwavelength Brillouin fiber laser (MW-BFL). Configuration has also been successfully demonstrated. The hybrid amplification from the 300 mW power of Raman pump (RP), 7.7 km long DCF, and 30 m DC-EDF that is being pumped bidirectionally results in a stable multiwavelength Brillouin peaks in the S-band region. Results obtained shows that the insertion of linear gain medium with bidirectional pumping of the DC-EDF into the cavity gives significant amplification and promotes the formation of stokes peaks in the S-band region. The number of Brillouin peaks generated is closely dependent on the DBFL and MW-BFL configuration, the Brillouin pump (BP) signal wavelength, the BP coupling ratio, and the RP power. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:881,883, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25036 [source] Configurations of germinal vesicle (GV) chromatin in the goat differ from those of other speciesMOLECULAR REPRODUCTION & DEVELOPMENT, Issue 2 2005Hong-Shu Sui Abstract Configuration of germinal vesicle (GV) chromatin has been studied and found correlated with the developmental competence of oocytes in several mammalian species. A common feature in the configuration of GV chromatin in the species studied so far is that the diffuse chromatin (the so called "NSN" pattern) condenses into a perinucleolar ring (the so called "SN" configuration) with follicular growth. However, no study has been published on the configuration of GV chromatin in the goat. Nor is it known whether the perinucleolar ring of condensed chromatin (CC) in an oocyte represents a step toward final maturation or atresia. Changes in configurations of GV chromatin and RNA synthesis during goat oocyte growth, atresia and maturation in vivo and in vitro were investigated in this study. Based on both the size of nucleoli and the degree of chromatin condensation, the GV chromatin of goat oocytes was classified into GV1 characterized by large nucleoli and diffuse chromatin, GV2 with medium-sized nucleoli and condensed net-like (GV2n) or clumped (GV2c) chromatin, GV3 with small nucleoli and net-like (GV3n) or clumped (GV3c) chromatin, and GV4 with no nucleolus but clumped chromatin. The results showed that (i) the configurations of GV chromatin in the goat differ from those of other species in that the chromatin did not condense into a perinucleolar ring; (ii) most of the goat oocytes are synchronized at the GV3n configuration before GVBD; (iii) the GVn pattern might represent a healthy state, but the GVc an atretic state; (iv) in both goats and mice, the GC-specific (Chromomycin A3, CMA3) and the AT-specific (Hoechst 33342) fluorochromes followed the same pattern of distribution in GV chromatin; (v) the nucleolar size decreased significantly with oocyte growth and maturation in vivo and in vitro; and (vi) goat oocytes began GVBD at 8 hr and had completed it by 20 hr after onset of estrus. The peculiar configuration of GV chromatin of goat oocytes can be a useful model for studies of morphological and functional changes of different nuclear compartments during the cell cycle and cell differentiation, and the functional differentiation between GV3n and GV3c might be used for reference to the question whether the "SN" configuration in other species inclines toward ovulation or atresia. Mol. Reprod. Dev. 71: 227,236, 2005. © 2005 Wiley-Liss, Inc. [source] Inappropriate ICD Therapy: Does Device Configuration Make a DifferencePACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 8 2006DWARAKRAJ SOUNDARRAJ Introduction: Inappropriate implantable cardioverter defibrillator (ICD) therapy (IT) is a common complication in patients with ICD. IT is commonly triggered by supraventricular tachycardias (SVT). Dual chamber ICDs (D-ICDs) may distinguish SVT from ventricular tachycardia/ventricular fibrillation better than single chamber ICDs (S-ICDs) and may be associated with a smaller incidence of IT. Methods: We reviewed the charts of 386 patients who had an ICD implanted for an AHA class I indication. Intracardiac electrograms were used to classify shocks as either appropriate or inappropriate. Results: Of 295 patients with an S-ICD, 66 (22.3%) received IT, compared to 5 (5.4%) of 91 patients with a D-ICD. The likelihood of being event-free at 1, 2, 3, and 4 years was 96.1%, 96.1%, 96.1%, and 89% for patients with D-ICD and 80.7%, 72.7%, 69.6%, and 66.4%, respectively, for patients with S-ICD (P < 0.001). Multivariate analysis showed no significant association with age, sex, history of atrial fibrillation, history of hypertension, or ejection fraction. SVTs were the commonest cause of IT in our patients. Conclusion: Patients with D-ICD are less likely to receive IT as compared to patients with S-ICD. [source] Alpha-retinals as Rhodopsin Chromophores,Preference for the 9- Z Configuration and Partial Agonist Activity,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 4 2008Yajie Wang The visual pigment rhodopsin, the photosensory element of the rod photoreceptor cell in the vertebrate retina, shows in combination with an endogenous ligand, 11- Z retinal, an astonishing photochemical performance. It exhibits an unprecedented quantum yield (0.67) in a highly defined and ultrafast photoisomerization process. This triggers the conformational changes leading to the active state Meta(rhodopsin) II. Retinal is covalently bound to Lys-296 of the protein opsin in a protonated Schiff base. The resulting positive charge delocalization over the terminal part of the polyene chain of retinal creates a conjugation defect that upon photoexcitation moves to the opposite end of the polyene. Shortening the polyene as in 4,5-dehydro,5,6-dihydro (alpha), 5,6-dihydro or 7,8-dihydro-analogs might facilitate photoisomerization of a 9- Z and a 11- Z bond. Here we describe pigment analogs generated with bovine opsin and 11- Z or 9- Z 4,5-dehydro,5,6-dihydro-retinal that were further characterized by UV,Vis and FTIR spectroscopy. The preference of opsin for native 11- Z retinal over the 9- Z isomer is reversed in 4,5-dehydro,5,6-dihydro-retinal. 9- Z 4,5-dehydro,5,6-dihydro-retinal readily generated a photosensitive pigment. This modification has no effect on the quantum yield, but affects the Batho,blueshifted intermediate (BSI) equilibrium and leads to a strong decrease in the G-protein activation rate because of a downshift of the pKa of the Meta I,Meta II equilibrium. [source] LES of a Confined Configuration using Oscillating Inflow ConditionsPROCEEDINGS IN APPLIED MATHEMATICS & MECHANICS, Issue 1 2003Michael Düsing In actual turbulent flow problems, in particular in gas turbine combustion chambers, flows are three dimensional, recirculating and turbulent in confined and complex geometries. Instationarities due to turbulence, combustion instabilities and oscillating inflow conditions require a highly time and spatial resolving procedure. 3D Large Eddy Simulations (LES) are therefore used in this work to study two confined coaxial air jets with oscillating velocity inflow conditions. The influences of the inflow, in particular frequency (f = 0 ÷ 1600 [Hz]) and amplitude, on the velocity are analysed. [source] | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||