WorldWideScience

Sample records for macrocyclic trichromophore bundle

  1. Macrocycles

    Energy Technology Data Exchange (ETDEWEB)

    Raymond, Kenneth N.; Xu, Jide; Pham, Tiffany A.

    2016-09-13

    The invention provides macrocycles useful in chelating metal ions, particularly radionuclides, to provide metal ion complexes. The invention also provides methods of using the compounds and complexes of the invention, such as in therapeutic and diagnostic applications.

  2. Macrocyclic fragrance materials

    DEFF Research Database (Denmark)

    Salvito, Daniel; Lapczynski, Aurelia; Sachse-Vasquez, Christen

    2011-01-01

    A screening-level aquatic environmental risk assessment for macrocyclic fragrance materials using a “group approach” is presented using data for 30 macrocyclic fragrance ingredients. In this group approach, conservative estimates of environmental exposure and ecotoxicological effects thresholds...... for compounds within two subgroups (15 macrocyclic ketones and 15 macrocyclic lactones/lactides) were used to estimate the aquatic ecological risk potential for these subgroups. It is reasonable to separate these fragrance materials into the two subgroups based on the likely metabolic pathway required...... for both regions is materials, and minimal in stream dilution (3:1), the conservatively predicted exposure concentrations for macrocyclic ketones would range from

  3. Synthesis of macrocyclic polyazomethines

    OpenAIRE

    Elizbarashvili,Elizbar; Matitaishvili,Tea; Topuria,Khatuna

    2007-01-01

    The synthesis of 20-membered macrocyclic polyazomethine dyes 3a and 3b from 4,4'-dihydroxybiphenyl-3,3'-dicarbaldehyde (2a) and 5,5'-diamino-4,4'-dihydroxybiphenyl-3,3'-dicarbaldehyde (2b) and macrocyclic polyazomethine pigments 4 and 5 from 3a is described.

  4. Luminescent macrocyclic lanthanide complexes

    Science.gov (United States)

    Raymond, Kenneth N [Berkeley, CA; Corneillie, Todd M [Campbell, CA; Xu, Jide [Berkeley, CA

    2012-05-08

    The present invention provides a novel class of macrocyclic compounds as well as complexes formed between a metal (e.g., lanthanide) ion and the compounds of the invention. Preferred complexes exhibit high stability as well as high quantum yields of lanthanide ion luminescence in aqueous media without the need for secondary activating agents. Preferred compounds incorporate hydroxy-isophthalamide moieties within their macrocyclic structure and are characterized by surprisingly low, non-specific binding to a variety of polypeptides such as antibodies and proteins as well as high kinetic stability. These characteristics distinguish them from known, open-structured ligands.

  5. Fourth symposium on macrocyclic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Christensen, J. J.; Izatt, R. M.

    1980-01-01

    Both theoretical and experimental aspects of the properties and behavior of synthetic and naturally occurring macrocyclic compounds are covered in this symposium. This document contains abstracts of the papers. (DLC)

  6. On Double Vector Bundles

    Institute of Scientific and Technical Information of China (English)

    Zhuo CHEN; Zhang Ju LIU; Yun He SHENG

    2014-01-01

    In this paper, we construct a category of short exact sequences of vector bundles and prove that it is equivalent to the category of double vector bundles. Moreover, operations on double vector bundles can be transferred to operations on the corresponding short exact sequences. In particular, we study the duality theory of double vector bundles in term of the corresponding short exact sequences. Examples including the jet bundle and the Atiyah algebroid are discussed.

  7. On Double Vector Bundles

    OpenAIRE

    Chen, Zhuo; Liu, Zhangju; Sheng, Yunhe

    2011-01-01

    In this paper, we construct a category of short exact sequences of vector bundles and prove that it is equivalent to the category of double vector bundles. Moreover, operations on double vector bundles can be transferred to operations on the corresponding short exact sequences. In particular, we study the duality theory of double vector bundles in term of the corresponding short exact sequences. Examples including the jet bundle and the Atiyah algebroid are discussed.

  8. Principal noncommutative torus bundles

    DEFF Research Database (Denmark)

    Echterhoff, Siegfried; Nest, Ryszard; Oyono-Oyono, Herve

    2008-01-01

    In this paper we study continuous bundles of C*-algebras which are non-commutative analogues of principal torus bundles. We show that all such bundles, although in general being very far away from being locally trivial bundles, are at least locally trivial with respect to a suitable bundle version...... of bivariant K-theory (denoted RKK-theory) due to Kasparov. Using earlier results of Echterhoff and Williams, we shall give a complete classification of principal non-commutative torus bundles up to equivariant Morita equivalence. We then study these bundles as topological fibrations (forgetting the group...... action) and give necessary and sufficient conditions for any non-commutative principal torus bundle being RKK-equivalent to a commutative one. As an application of our methods we shall also give a K-theoretic characterization of those principal torus-bundles with H-flux, as studied by Mathai...

  9. Macrocyclic trichothecenes as antifungal and anticancer compounds.

    Science.gov (United States)

    de Carvalho, Maira Peres; Weich, Herbert; Abraham, Wolf-Rainer

    2016-01-01

    Trichothecenes are sesquiterpenoid metabolites produced by fungi and species of the plant genus Baccharis, family Asteraceae. They comprise a tricyclic core with an epoxide at C-12 and C-13 and can be grouped into non-macrocyclic and macrocyclic compounds. While many of these compounds are of concern in agriculture, the macrocyclic metabolites have been evaluated as antiviral, anti-cancer, antimalarial and antifungal compounds. Some known cytotoxic responses on eukaryotic cells include inhibition of protein, DNA and RNA syntheses, interference with mitochondrial function, effects on cell division and membranes. These targets however have been elucidated essentially employing non-macrocyclic trichothecenes and only one or two closely related macrocyclic compounds. For several macrocyclic trichothecenes high selectivity against fungal species and against cancer cell lines have been reported suggesting that the macrocycle and its stereochemistry are of crucial importance regarding biological activity and selectivity. This review is focused on compounds belonging to the macrocyclic type, where a cyclic diester or triester ring binds to the trichothecane moiety at C-4 and C- 15 leading to natural products belonging to the groups of satratoxins, verrucarins, roridins, myrotoxins and baccharinoids. Their biological activities, cytotoxic mechanisms and structure-activity relationships (SAR) are discussed. From the reported data it becomes evident that even small changes in the molecules can lead to pronounced effects on biological activity or selectivity against cancer cells lines. Understanding the underlying mechanisms may help to design highly specific drugs for cancer therapy.

  10. Parabolic k-ample bundles

    CERN Document Server

    Biswas, Indranil

    2011-01-01

    We construct projectivization of a parabolic vector bundle and a tautological line bundle over it. It is shown that a parabolic vector bundle is ample if and only if the tautological line bundle is ample. This allows us to generalize the notion of a k-ample bundle, introduced by Sommese, to the context of parabolic bundles. A parabolic vector bundle $E_*$ is defined to be k-ample if the tautological line bundle ${\\mathcal O}_{{\\mathbb P}(E_*)}(1)$ is $k$--ample. We establish some properties of parabolic k-ample bundles.

  11. Radical photocyclization route for macrocyclic lactone ring expansion and conversion to macrocyclic lactams and ketones.

    Science.gov (United States)

    Nishikawa, Keisuke; Yoshimi, Yasuharu; Maeda, Kousuke; Morita, Toshio; Takahashi, Ichiro; Itou, Tatsuya; Inagaki, Sho; Hatanaka, Minoru

    2013-01-18

    A new method for the synthesis of macrocyclic lactones, lactams, and ketones, which utilizes photoinduced intramolecular radical cyclization reactions of substrates containing tethered carboxylic acids and α,β-unsaturated carbonyl moieties, has been uncovered. Photocyclization of the carboxylic acids tethered acrylate ester, which were prepared starting from the macrocyclic lactones, gave the two-carbon elongated macrocyclic lactones via decarboxylation. Similar photoreactions of carboxylic acid tethered acryl amide or α,β-unsaturated ketone moieties, which were also prepared starting from the macrocyclic lactones, produced macrocyclic lactams or ketones, respectively. The simple approach can be readily applied to the preparation of a variety of macrocyclic lactones, lactams, and ketones with tunable ring sizes.

  12. Templating irreversible covalent macrocyclization by using anions.

    Science.gov (United States)

    Kataev, Evgeny A; Kolesnikov, Grigory V; Arnold, Rene; Lavrov, Herman V; Khrustalev, Victor N

    2013-03-11

    Inorganic anions were used as templates in the reaction between a diamine and an activated diacid to form macrocyclic amides. The reaction conditions were found to perform the macrocyclization sufficiently slow to observe a template effect. A number of analytical methods were used to clarify the reaction mechanisms and to show that the structure of the intermediate plays a decisive role in determining the product distribution. For the macrocyclization under kinetic control, it was shown that the amount of a template, the conformational rigidity of building blocks, and the anion affinities of reaction components and intermediates are important parameters that one should take into consideration to achieve high yields.

  13. Engineering macrocyclic figure-eight motif

    Indian Academy of Sciences (India)

    V Haridas; Harinder Singh; Yogesh K Sharma; Kashmiri Lal

    2007-05-01

    The design and synthesis of figure-eight macrocycles are very scarce owing to the intricacies and lack of predictability from first principles. This review emphasizes on discrete macrocyclic systems both synthetic and natural with a defined figure eight knotted topology. In almost all the helical macrocycles, the helical arrangement is held by intramolecular hydrogen bonding or as a backbone requirement, but in all cases, a planar graph can be drawn and so these compounds are trivial from the topological stand point. Nature presents great deal of complexity in terms of structures in macromolecules like DNA and proteins and also displays intriguing topology in simple natural products. Patellamide, tawicyclamides, nosiheptide and thiostrepton are natural products with figure eight topology which shows interesting biological activity. Expanded porphyrins, Cu(II) complexes of thiomacrocycles, cyclic peptides and oligoesters are synthetic macrocycles showing intriguing topology. Analysis of structure and folding behaviour will enable chemists to design molecules with intriguing topology.

  14. The ABCDEF Implementation Bundle

    Directory of Open Access Journals (Sweden)

    Annachiara Marra

    2016-08-01

    Full Text Available Long-term morbidity, long-term cognitive impairment and hospitalization-associated disability are common occurrence in the survivors of critical illness, with significant consequences for patients and for the caregivers. The ABCDEF bundle represents an evidence-based guide for clinicians to approach the organizational changes needed for optimizing ICU patient recovery and outcomes. The ABCDEF bundle includes: Assess, Prevent, and Manage Pain, Both Spontaneous Awakening Trials (SAT and Spontaneous Breathing Trials (SBT, Choice of analgesia and sedation, Delirium: Assess, Prevent, and Manage, Early mobility and Exercise, and Family engagement. The purpose of this review is to describe the core features of the ABCDEF bundle.

  15. Subtleties Concerning Conformal Tractor Bundles

    CERN Document Server

    Graham, C Robin

    2012-01-01

    The realization of tractor bundles as associated bundles in conformal geometry is studied. It is shown that different natural choices of principal bundle with normal Cartan connection corresponding to a given conformal manifold can give rise to topologically distinct associated tractor bundles for the same inducing representation. Consequences for homogeneous models and conformal holonomy are described. A careful presentation is made of background material concerning standard tractor bundles and equivalence between parabolic geometries and underlying structures.

  16. Bending rigid molecular rods: formation of oligoproline macrocycles.

    Science.gov (United States)

    Scully, Conor C G; Rai, Vishal; Poda, Gennadiy; Zaretsky, Serge; Burns, Darcy C; Houliston, R Scott; Lou, Tiantong; Yudin, Andrei K

    2012-12-01

    Bent but not broken: cyclic oligoprolines are accessed in a reaction that effectively bends rigid oligoproline peptides (see scheme; TBDMS=tert-butyldimethylsilyl). The stitching is accomplished during macrocyclization enabled by aziridine aldehydes and isocyanides. Molecular modeling studies suggest that electrostatic attraction between the termini of the linear peptide is pivotal for macrocyclization. The macrocycles were studied by circular dichroism with a polyproline II structure being observed in larger macrocycles.

  17. Creating molecular macrocycles for anion recognition

    Directory of Open Access Journals (Sweden)

    Amar H. Flood

    2016-03-01

    Full Text Available The creation and functionality of new classes of macrocycles that are shape persistent and can bind anions is described. The genesis of triazolophane macrocycles emerges out of activity surrounding 1,2,3-triazoles made using click chemistry; and the same triazoles are responsible for anion capture. Mistakes made and lessons learnt in anion recognition provide deeper understanding that, together with theory, now provides for computer-aided receptor design. The lessons are acted upon in the creation of two new macrocycles. First, cyanostars are larger and like to capture large anions. Second is tricarb, which also favors large anions but shows a propensity to self-assemble in an orderly and stable manner, laying a foundation for future designs of hierarchical nanostructures.

  18. Right bundle branch block

    DEFF Research Database (Denmark)

    Bussink, Barbara E; Holst, Anders Gaarsdal; Jespersen, Lasse

    2013-01-01

    AimsTo determine the prevalence, predictors of newly acquired, and the prognostic value of right bundle branch block (RBBB) and incomplete RBBB (IRBBB) on a resting 12-lead electrocardiogram in men and women from the general population.Methods and resultsWe followed 18 441 participants included.......5%/2.3% in women, P Right bundle branch block was associated with significantly...... increased all-cause and cardiovascular mortality in both genders with age-adjusted hazard ratios (HR) of 1.31 [95% confidence interval (CI), 1.11-1.54] and 1.87 (95% CI, 1.48-2.36) in the gender pooled analysis with little attenuation after multiple adjustment. Right bundle branch block was associated...

  19. Bundles of Banach algebras

    Directory of Open Access Journals (Sweden)

    J. W. Kitchen

    1994-01-01

    Full Text Available We study bundles of Banach algebras π:A→X, where each fiber Ax=π−1({x} is a Banach algebra and X is a compact Hausdorff space. In the case where all fibers are commutative, we investigate how the Gelfand representation of the section space algebra Γ(π relates to the Gelfand representation of the fibers. In the general case, we investigate how adjoining an identity to the bundle π:A→X relates to the standard adjunction of identities to the fibers.

  20. Principal -bundles on Nodal Curves

    Indian Academy of Sciences (India)

    Usha N Bhosle

    2001-08-01

    Let be a connected semisimple affine algebraic group defined over . We study the relation between stable, semistable -bundles on a nodal curve and representations of the fundamental group of . This study is done by extending the notion of (generalized) parabolic vector bundles to principal -bundles on the desingularization of and using the correspondence between them and principal -bundles on . We give an isomorphism of the stack of generalized parabolic bundles on with a quotient stack associated to loop groups. We show that if is simple and simply connected then the Picard group of the stack of principal -bundles on is isomorphic to ⊕ , being the number of components of .

  1. On projective space bundle with nef normalized tautological line bundle

    CERN Document Server

    Yasutake, Kazunori

    2011-01-01

    In this paper, we study the structure of projective space bundles whose relative anti-canonical line bundle is nef. As an application, we get a characterization of abelian varieties up to finite etale covering.

  2. Enzymatic Macrocyclization of 1,2,3-Triazole Peptide Mimetics.

    Science.gov (United States)

    Oueis, Emilia; Jaspars, Marcel; Westwood, Nicholas J; Naismith, James H

    2016-05-04

    The macrocyclization of linear peptides is very often accompanied by significant improvements in their stability and biological activity. Many strategies are available for their chemical macrocyclization, however, enzyme-mediated methods remain of great interest in terms of synthetic utility. To date, known macrocyclization enzymes have been shown to be active on both peptide and protein substrates. Here we show that the macrocyclization enzyme of the cyanobactin family, PatGmac, is capable of macrocyclizing substrates with one, two, or three 1,4-substituted 1,2,3-triazole moieties. The introduction of non-peptidic scaffolds into macrocycles is highly desirable in tuning the activity and physical properties of peptidic macrocycles. We have isolated and fully characterized nine non-natural triazole-containing cyclic peptides, a further ten molecules are also synthesized. PatGmac has now been shown to be an effective and versatile tool for the ring closure by peptide bond formation.

  3. Kernel bundle EPDiff

    DEFF Research Database (Denmark)

    Sommer, Stefan Horst; Lauze, Francois Bernard; Nielsen, Mads

    2011-01-01

    In the LDDMM framework, optimal warps for image registration are found as end-points of critical paths for an energy functional, and the EPDiff equations describe the evolution along such paths. The Large Deformation Diffeomorphic Kernel Bundle Mapping (LDDKBM) extension of LDDMM allows scale space...

  4. Universal Lagrangian bundles

    NARCIS (Netherlands)

    Sepe, D.

    2013-01-01

    The obstruction to construct a Lagrangian bundle over a fixed integral affine manifold was constructed by Dazord and Delzant (J Differ Geom 26:223–251, 1987) and shown to be given by ‘twisted’ cup products in Sepe (Differ GeomAppl 29(6): 787–800, 2011). This paper uses the topology of universal Lagr

  5. ALUMINUM BOX BUNDLING PRESS

    Directory of Open Access Journals (Sweden)

    Iosif DUMITRESCU

    2015-05-01

    Full Text Available In municipal solid waste, aluminum is the main nonferrous metal, approximately 80- 85% of the total nonferrous metals. The income per ton gained from aluminum recuperation is 20 times higher than from glass, steel boxes or paper recuperation. The object of this paper is the design of a 300 kN press for aluminum box bundling.

  6. Rapid synthesis of macrocycles from diol precursors

    DEFF Research Database (Denmark)

    Wingstrand, Magnus; Madsen, Charlotte Marie; Clausen, Mads Hartvig

    2009-01-01

    A method for the formation of synthetic macrocycles with different ring sizes from diols is presented. Reacting a simple diol precursor with electrophilic reagents leads to a cyclic carbonate, sulfite or phosphate in a single step in 25-60% yield. Converting the cyclization precursor to a bis-ele...

  7. Deformation quantization of principal bundles

    CERN Document Server

    Aschieri, Paolo

    2016-01-01

    We outline how Drinfeld twist deformation techniques can be applied to the deformation quantization of principal bundles into noncommutative principal bundles, and more in general to the deformation of Hopf-Galois extensions. First we twist deform the structure group in a quantum group, and this leads to a deformation of the fibers of the principal bundle. Next we twist deform a subgroup of the group of authomorphisms of the principal bundle, and this leads to a noncommutative base space. Considering both deformations we obtain noncommutative principal bundles with noncommutative fiber and base space as well.

  8. Helices and vector bundles

    CERN Document Server

    Rudakov, A N

    1990-01-01

    This volume is devoted to the use of helices as a method for studying exceptional vector bundles, an important and natural concept in algebraic geometry. The work arises out of a series of seminars organised in Moscow by A. N. Rudakov. The first article sets up the general machinery, and later ones explore its use in various contexts. As to be expected, the approach is concrete; the theory is considered for quadrics, ruled surfaces, K3 surfaces and P3(C).

  9. Bundling harvester; Nippukorjausharvesteri

    Energy Technology Data Exchange (ETDEWEB)

    Koponen, K. [Eko-Log Oy, Kuopio (Finland)

    1996-12-31

    The staring point of the project was to design and construct, by taking the silvicultural point of view into account, a harvesting and processing system especially for energy-wood, containing manually driven bundling harvester, automatizing of the harvester, and automatized loading. The equipment forms an ideal method for entrepreneur`s-line harvesting. The target is to apply the system also for owner`s-line harvesting. The profitability of the system promotes the utilization of the system in both cases. The objectives of the project were: to construct a test equipment and prototypes for all the project stages, to carry out terrain and strain tests in order to examine the usability and durability, as well as the capacity of the machine, to test the applicability of the Eko-Log system in simultaneous harvesting of energy and pulp woods, and to start the marketing and manufacturing of the products. The basic problems of the construction of the bundling harvester have been solved using terrain-tests. The prototype machine has been shown to be operable. Loading of the bundles to form sufficiently economically transportable loads has been studied, and simultaneously, the branch-biomass has been tried to be utilized without loosing the profitability of transportation. The results have been promising, and will promote the profitable utilization of wood-energy

  10. Synthesis and characterization of new azo containing Schiff base macrocycle

    Institute of Scientific and Technical Information of China (English)

    Saeed Malek-Ahmadi; Amir Abdolmaleki

    2011-01-01

    Fully conjugated Schiff base macrocycle has been prepared through a simple and mild condition, a one-pot cyclization procedure of four-component without using a template. The condensation reaction of related bis (hydroxybenzaldehyde) with phenylenediamines to prepare a conjugated [2 + 2] Schiff base macrocycle has been investigated and fluorescent [2 + 2] Schiff base macrocycles with N2O2 binding pockets has been prepared and characterized by elemental analysis,' H NMR, IR, fluorescent, UV-visible and MALDI mass spectroscopies.

  11. Amide-based Fluorescent Macrocyclic Anion Receptors

    Institute of Scientific and Technical Information of China (English)

    ZENG, Zhen-Ya(曾振亚); XU, Kuo-Xi(徐括喜); HE, Yong-Bing(何永炳); LIU, Shun-Ying(刘顺英); WU, Jin-Long(吴进龙); WEI, Lan-Hua(隗兰华); MENG, Ling-Zhi(孟令芝)

    2004-01-01

    Two fluorescent anion receptors (1 and 2) based on amide macrocycle were synthesized and corresponding fluorescence quenching induced by anion complexation was observed in different degree. Receptors form 1: 1 complexes with anions by hydrogen bonding interactions. Receptor 1 bound anions in the order of F->Cl->H2PO4->CH3COO->>Br-, I- and receptor 2 showed high selectivity to F- over other anions.

  12. Managing bundled payments.

    Science.gov (United States)

    Draper, Andrew

    2011-04-01

    Results of Medicare's ACE demonstration project and Geisinger Health System's ProvenCare initiative provide insight into the challenges hospitals will face as bundled payment proliferates. An early analysis of these results suggests that hospitals would benefit from bringing full automation using clinical IT tools to bear in their efforts to meet these challenges. Other important factors contributing to success include board and physician leadership, organizational structure, pricing methodology for bidding, evidence-based medical practice guidelines, supply cost management, process efficiency management, proactive and aggressive case management, business development and marketing strategy, and the financial management system.

  13. Differential calculi on noncommutative bundles

    OpenAIRE

    Pflaum, Markus J.; Schauenburg, Peter

    1996-01-01

    We introduce a category of noncommutative bundles. To establish geometry in this category we construct suitable noncommutative differential calculi on these bundles and study their basic properties. Furthermore we define the notion of a connection with respect to a differential calculus and consider questions of existence and uniqueness. At the end these constructions are applied to basic examples of noncommutative bundles over a coquasitriangular Hopf algebra.

  14. Nefness of adjoint bundles for ample vector bundles

    Directory of Open Access Journals (Sweden)

    Hidetoshi Maeda

    1995-11-01

    Full Text Available Let E be an ample vector bundle of rank >1 on a smooth complex projective variety X of dimension n. This paper gives a classification of pairs (X,E whose adjoint bundles K_X+det E are not nef in the case when  r=n-2.

  15. Synthesis of the macrocyclic core of (-)-pladienolide B

    DEFF Research Database (Denmark)

    Skaanderup, Philip Robert; Jensen, T.

    2008-01-01

    An efficient synthesis of the macrocyclic core of (-)-pladienolide B is disclosed. The concise route relies on a chiral auxiliary-mediated asymmetric aldol addition and an osmium-catalyzed asymmetric dihydroxylation to install the three oxygenated stereocenters of the macrocycle. This purely reag...

  16. Observations on the Influence of Precursor Conformations on Macrocyclization Reactions

    DEFF Research Database (Denmark)

    Hammershøj, Peter; Beldring, Klavs; Nielsen, Anders R.

    2016-01-01

    macrocyclization to afford a mixture of diastereomeric sulfites, subjection of the other precursor to identical reaction conditions resulted in the isolation of the linear dichloride. We hypothesize that there is a difference in the ability of the two molecules to adopt a conformation that is germane...... to macrocyclization, a proposition that is supported by conformational analyses using molecular mechanics....

  17. Bundle Security Protocol for ION

    Science.gov (United States)

    Burleigh, Scott C.; Birrane, Edward J.; Krupiarz, Christopher

    2011-01-01

    This software implements bundle authentication, conforming to the Delay-Tolerant Networking (DTN) Internet Draft on Bundle Security Protocol (BSP), for the Interplanetary Overlay Network (ION) implementation of DTN. This is the only implementation of BSP that is integrated with ION.

  18. Vector Bundles And F Theory

    CERN Document Server

    Friedman, R; Witten, Edward

    1997-01-01

    To understand in detail duality between heterotic string and F theory compactifications, it is important to understand the construction of holomorphic G bundles over elliptic Calabi-Yau manifolds, for various groups G. In this paper, we develop techniques to describe these bundles, and make several detailed comparisons between the heterotic string and F theory.

  19. Vector Bundles And F Theory

    OpenAIRE

    Friedman, Robert; Morgan, John; Witten, Edward

    1997-01-01

    To understand in detail duality between heterotic string and F theory compactifications, it is important to understand the construction of holomorphic G bundles over elliptic Calabi-Yau manifolds, for various groups G. In this paper, we develop techniques to describe the bundles, and make several detailed comparisons between the heterotic string and F theory.

  20. Bundle Formation in Biomimetic Hydrogels

    NARCIS (Netherlands)

    Jaspers, Maarten; Pape, A C H; Voets, Ilja K; Rowan, Alan E; Portale, Giuseppe; Kouwer, Paul H J

    2016-01-01

    Bundling of single polymer chains is a crucial process in the formation of biopolymer network gels that make up the extracellular matrix and the cytoskeleton. This bundled architecture leads to gels with distinctive properties, including a large-pore-size gel formation at very low concentrations and

  1. Synthesis of New Macrocyclic Polyamides as Antimicrobial Agent Candidates

    Directory of Open Access Journals (Sweden)

    Osama I. Abd El-Salam

    2012-12-01

    Full Text Available A series of macrocyclic imides and Schiff-bases have been prepared via the cyclocondensation of pyridine-2,6-dicarbonyl dichloride (1 with L-ornithine methyl ester to give the corresponding macrocyclic bisester 2. Treatment of 2 with hydrazine hydrate gave macrocyclic bisacid hydrazide 3, which was used as starting material. Condensation of bishydrazide 3 with diacid anhydrides or aromatic aldehydes in refluxing acetic acid or ethanol gave the corresponding macrocyclic bisimides 4, 5a,b and macrocyclic bis- hydrazones 6a–j, respectively. The structure assignments of the new compounds were based on chemical and spectroscopic evidence. The antimicrobial screening showed that many of these newly synthesized compounds have good antimicrobial activities, comparable to ampicillin and ketaconazole used as reference drugs.

  2. Fiber bundle phase conjugate mirror

    Science.gov (United States)

    Ward, Benjamin G.

    2012-05-01

    An improved method and apparatus for passively conjugating the phases of a distorted wavefronts resulting from optical phase mismatch between elements of a fiber laser array are disclosed. A method for passively conjugating a distorted wavefront comprises the steps of: multiplexing a plurality of probe fibers and a bundle pump fiber in a fiber bundle array; passing the multiplexed output from the fiber bundle array through a collimating lens and into one portion of a non-linear medium; passing the output from a pump collection fiber through a focusing lens and into another portion of the non-linear medium so that the output from the pump collection fiber mixes with the multiplexed output from the fiber bundle; adjusting one or more degrees of freedom of one or more of the fiber bundle array, the collimating lens, the focusing lens, the non-linear medium, or the pump collection fiber to produce a standing wave in the non-linear medium.

  3. Twisted Vector Bundles on Pointed Nodal Curves

    Indian Academy of Sciences (India)

    Ivan Kausz

    2005-05-01

    Motivated by the quest for a good compactification of the moduli space of -bundles on a nodal curve we establish a striking relationship between Abramovich’s and Vistoli’s twisted bundles and Gieseker vector bundles.

  4. Macrocyclic 2,7-Anthrylene Oligomers.

    Science.gov (United States)

    Yamamoto, Yuta; Wakamatsu, Kan; Iwanaga, Tetsuo; Sato, Hiroyasu; Toyota, Shinji

    2016-05-06

    A macrocyclic compound consisting of six 2,7-anthrylene units was successfully synthesized by Ni-mediated coupling of the corresponding dibromo precursor as a novel π-conjugated compound. This compound was sufficiently stable and soluble in organic solvents due to the presence of mesityl groups. X-ray analysis showed that the molecule had a nonplanar and hexagonal wheel-shaped framework of approximately S6 symmetry. The dynamic process between two S6 structures was observed by using the dynamic NMR technique, the barrier being 58 kJ mol(-1) . The spectroscopic properties of the hexamer were compared with those of analogous linear oligomers.

  5. Macrocyclic olefin metathesis at high concentrations by using a phase-separation strategy.

    Science.gov (United States)

    Raymond, Michaël; Holtz-Mulholland, Michael; Collins, Shawn K

    2014-09-26

    Macrocyclic olefin metathesis has seen advances in the areas of stereochemistry, chemoselectivity, and catalyst stability, but strategies aimed at controlling dilution effects in macrocyclizations are rare. Herein, a protocol to promote macrocyclic olefin metathesis, one of the most common synthetic tools used to prepare macrocycles, at relatively high concentrations (up to 60 mM) is described by exploitation of a phase-separation strategy. A variety of macrocyclic skeletons could be prepared having either different alkyl, aryl, or amino acids spacers.

  6. Semiflexible Biopolymers in Bundled Arrangements

    Directory of Open Access Journals (Sweden)

    Jörg Schnauß

    2016-07-01

    Full Text Available Bundles and networks of semiflexible biopolymers are key elements in cells, lending them mechanical integrity while also enabling dynamic functions. Networks have been the subject of many studies, revealing a variety of fundamental characteristics often determined via bulk measurements. Although bundles are equally important in biological systems, they have garnered much less scientific attention since they have to be probed on the mesoscopic scale. Here, we review theoretical as well as experimental approaches, which mainly employ the naturally occurring biopolymer actin, to highlight the principles behind these structures on the single bundle level.

  7. Evaluating big deal journal bundles.

    Science.gov (United States)

    Bergstrom, Theodore C; Courant, Paul N; McAfee, R Preston; Williams, Michael A

    2014-07-01

    Large commercial publishers sell bundled online subscriptions to their entire list of academic journals at prices significantly lower than the sum of their á la carte prices. Bundle prices differ drastically between institutions, but they are not publicly posted. The data that we have collected enable us to compare the bundle prices charged by commercial publishers with those of nonprofit societies and to examine the types of price discrimination practiced by commercial and nonprofit journal publishers. This information is of interest to economists who study monopolist pricing, librarians interested in making efficient use of library budgets, and scholars who are interested in the availability of the work that they publish.

  8. Stable extensions by line bundles

    CERN Document Server

    Teixidor-i-Bigas, M

    1997-01-01

    Let C be an algebraic curve of genus g. Consider extensions E of a vector bundle F'' of rank n'' by a vector bundle F' of rank n'. The following statement was conjectured by Lange: If 0bundle. Our method uses a degeneration argument to a reducible curve.

  9. Predicting bioactive conformations and binding modes of macrocycles

    Science.gov (United States)

    Anighoro, Andrew; de la Vega de León, Antonio; Bajorath, Jürgen

    2016-10-01

    Macrocyclic compounds experience increasing interest in drug discovery. It is often thought that these large and chemically complex molecules provide promising candidates to address difficult targets and interfere with protein-protein interactions. From a computational viewpoint, these molecules are difficult to treat. For example, flexible docking of macrocyclic compounds is hindered by the limited ability of current docking approaches to optimize conformations of extended ring systems for pose prediction. Herein, we report predictions of bioactive conformations of macrocycles using conformational search and binding modes using docking. Conformational ensembles generated using specialized search technique of about 70 % of the tested macrocycles contained accurate bioactive conformations. However, these conformations were difficult to identify on the basis of conformational energies. Moreover, docking calculations with limited ligand flexibility starting from individual low energy conformations rarely yielded highly accurate binding modes. In about 40 % of the test cases, binding modes were approximated with reasonable accuracy. However, when conformational ensembles were subjected to rigid body docking, an increase in meaningful binding mode predictions to more than 50 % of the test cases was observed. Electrostatic effects did not contribute to these predictions in a positive or negative manner. Rather, achieving shape complementarity at macrocycle-target interfaces was a decisive factor. In summary, a combined computational protocol using pre-computed conformational ensembles of macrocycles as a starting point for docking shows promise in modeling binding modes of macrocyclic compounds.

  10. The Atiyah Bundle and Connections on a Principal Bundle

    Indian Academy of Sciences (India)

    Indranil Biswas

    2010-06-01

    Let be a ∞ manifold and a Lie a group. Let $E_G$ be a ∞ principal -bundle over . There is a fiber bundle $\\mathcal{C}(E_G)$ over whose smooth sections correspond to the connections on $E_G$. The pull back of $E_G$ to $\\mathcal{C}(E_G)$ has a tautological connection. We investigate the curvature of this tautological connection.

  11. Observations on the Influence of Precursor Conformations on Macrocyclization Reactions

    DEFF Research Database (Denmark)

    Hammershøj, Peter; Beldring, Klavs; Nielsen, Anders R.;

    2016-01-01

    Macrocycles hold great promise in drug discovery as an underutilized class of lead compounds. The low abundance of these molecules can, in part, be explained by the inherent difficulties in the synthesis of macrocycles and the lack of general methods for their rapid assembly. We have undertaken...... a research program aimed at developing methods for facile synthesis of macrocycles from simple precursors. The synthesis of two new cyclization precursors is described and the results of their reaction with thionyl chloride are presented and discussed. Whereas one acyclic diol smoothly underwent...

  12. Left bundle-branch block

    DEFF Research Database (Denmark)

    Risum, Niels; Strauss, David; Sogaard, Peter

    2013-01-01

    The relationship between myocardial electrical activation by electrocardiogram (ECG) and mechanical contraction by echocardiography in left bundle-branch block (LBBB) has never been clearly demonstrated. New strict criteria for LBBB based on a fundamental understanding of physiology have recently...

  13. Bundling ecosystem services in Denmark

    DEFF Research Database (Denmark)

    Turner, Katrine Grace; Odgaard, Mette Vestergaard; Bøcher, Peder Klith;

    2014-01-01

    We made a spatial analysis of 11 ecosystem services at a 10 km × 10 km grid scale covering most of Denmark. Our objective was to describe their spatial distribution and interactions and also to analyze whether they formed specific bundle types on a regional scale in the Danish cultural landscape....... We found clustered distribution patterns of ecosystem services across the country. There was a significant tendency for trade-offs between on the one hand cultural and regulating services and on the other provisioning services, and we also found the potential of regulating and cultural services...... to form synergies. We identified six distinct ecosystem service bundle types, indicating multiple interactions at a landscape level. The bundle types showed specialized areas of agricultural production, high provision of cultural services at the coasts, multifunctional mixed-use bundle types around urban...

  14. Left bundle-branch block

    DEFF Research Database (Denmark)

    Risum, Niels; Strauss, David; Sogaard, Peter;

    2013-01-01

    The relationship between myocardial electrical activation by electrocardiogram (ECG) and mechanical contraction by echocardiography in left bundle-branch block (LBBB) has never been clearly demonstrated. New strict criteria for LBBB based on a fundamental understanding of physiology have recently...

  15. Vector bundles on toric varieties

    CERN Document Server

    Gharib, Saman

    2011-01-01

    Following Sam Payne's work, we study the existence problem of nontrivial vector bundles on toric varieties. The first result we prove is that every complete fan admits a nontrivial conewise linear multivalued function. Such functions could potentially be the Chern classes of toric vector bundles. Then we use the results of Corti\\~nas, Haesemeyer, Walker and Weibel to show that the (non-equivariant) Grothendieck group of the toric 3-fold studied by Payne is large, so the variety has a nontrivial vector bundle. Using the same computation, we show that every toric 3-fold X either has a nontrivial line bundle, or there is a finite surjective toric morphism from Y to X, such that Y has a large Grothendieck group.

  16. Fabrication of electrospun nanofibers bundles

    Science.gov (United States)

    Ye, Junjun; Sun, Daoheng

    2007-12-01

    Aligned nanofibers, filament bundle composed of large number of nanofibers have potential applications such as bio-material, composite material etc. A series of electrospinning experiments have been conducted to investigate the electrospinning process,in which some parameters such as polymer solution concentration, bias voltage, distance between spinneret and collector, solution flow rate etc have been setup to do the experiment of nanofibers bundles construction. This work firstly reports electrospun nanofiber bundle through non-uniform electrical field, and nanofibers distributed in different density on electrodes from that between them. Thinner nanofibers bundle with a few numbers of nanofiber is collected for 3 seconds; therefore it's also possible that the addressable single nanofiber could be collected to bridge two electrodes.

  17. Reconnection of superfluid vortex bundles.

    Science.gov (United States)

    Alamri, Sultan Z; Youd, Anthony J; Barenghi, Carlo F

    2008-11-21

    Using the vortex filament model and the Gross-Pitaevskii nonlinear Schroedinger equation, we show that bundles of quantized vortex lines in He II are structurally robust and can reconnect with each other maintaining their identity. We discuss vortex stretching in superfluid turbulence and show that, during the bundle reconnection process, kelvin waves of large amplitude are generated, in agreement with the finding that helicity is produced by nearly singular vortex interactions in classical Euler flows.

  18. Enantiocontrol in Macrocycle Formation from Catalytic MetalCarbene Transformations

    Institute of Scientific and Technical Information of China (English)

    DOYLE, Michael P.; DOYLE, Michael P; HU, Wen-Hao(胡文浩); 胡文浩

    2001-01-01

    The development of catalytic metal carbene transformations for the construction of macrocyclic lactones has dramatically increased their synthetic advantages.This is the first review of this developing methodology.

  19. Structural basis for precursor protein-directed ribosomal peptide macrocyclization

    Energy Technology Data Exchange (ETDEWEB)

    Li, Kunhua; Condurso, Heather L.; Li, Gengnan; Ding, Yousong; Bruner, Steven D. (Florida)

    2016-11-11

    Macrocyclization is a common feature of natural product biosynthetic pathways including the diverse family of ribosomal peptides. Microviridins are architecturally complex cyanobacterial ribosomal peptides that target proteases with potent reversible inhibition. The product structure is constructed via three macrocyclizations catalyzed sequentially by two members of the ATP-grasp family, a unique strategy for ribosomal peptide macrocyclization. Here we describe in detail the structural basis for the enzyme-catalyzed macrocyclizations in the microviridin J pathway of Microcystis aeruginosa. The macrocyclases MdnC and MdnB interact with a conserved α-helix of the precursor peptide using a novel precursor-peptide recognition mechanism. The results provide insight into the unique protein–protein interactions that are key to the chemistry, suggest an origin for the natural combinatorial synthesis of microviridin peptides, and provide a framework for future engineering efforts to generate designed compounds.

  20. Synthesis of novel symmetrical macrocycle via oxidative homocoupling of bisalkyne

    Energy Technology Data Exchange (ETDEWEB)

    Kamalulazmy, Nurulain; Hassan, Nurul Izzaty [School of Chemical Sciences and Food Technology, Universiti Kebangsaan Malaysia, 43600 UKM Bangi, Selangor Darul Ehsan (Malaysia)

    2014-09-03

    A novel symmetrical macrocycle has been synthesised via oxidative homocoupling of bisalkyne, diprop-2-ynyl pyridine-2,6-dicarboxylate mediated by copper (I) iodide (CuI) and 4-dimethylaminopyridine (DMAP). The precursor compound was synthesised from 2,6-pyridine dicarbonyl dichloride and propargyl alcohol in the presence of triethylamine. The reaction mixture was stirred overnight and further purified via column chromatograpy with 76% yield. Single crystal for X-ray study was obtained by recrystallization from acetone. Subsequently, a symmetrical macrocycle was synthesised from oxidative homocoupling of precursor compound in open atmosphere. The crude product was purified by column chromatography to furnish macrocycle compound with 5% yield. Both compounds were characterised by IR, {sup 1}H and {sup 13}C NMR and mass spectral techniques. The unusual conformation of the bisalkyne and twisted conformation of designed macrocycle has influence the percentage yield. This has been studied thoroughly by X-ray crystallography and electronic structure calculations.

  1. Rules of Macrocycle Topology: A [13]-Macrodilactone Case Study.

    Science.gov (United States)

    Magpusao, Anniefer N; Rutledge, Kelli; Hamlin, Trevor A; Lawrence, Jean-Marc; Mercado, Brandon Q; Leadbeater, Nicholas E; Peczuh, Mark W

    2016-04-18

    Shape is an inherent trait of a molecule that dictates how it interacts with other molecules, either in binding events or intermolecular reactions. Large-ring macrocyclic compounds in particular leverage their shape when they are selectively bound by biomolecules and also when they exhibit macrocyclic diastereoselectivity. Nonetheless, rules that link structural parameters to the conformation of a macrocycle are still rudimentary. Here we use a structural investigation of a family of [13]-macrodilactones as a case study to develop rules that can be applied generally to macrocycles of different sizes and with a variety of functionality. A characteristic "ribbon" shape is adopted by the [13]-macrodilactones in the absence of stereogenic centres, which exhibits planar chirality. When one stereogenic centre at key positions on the backbone is incorporated into the structure, the planar chirality is dictated by the configuration of the centre. In cases where two stereogenic centres are present, their relationships can either reinforce the characteristic ribbon shape or induce alternative shapes to be adopted. The rules established in the case study are then applied to the analysis of a structure of the natural product migrastatin. They lay the groundwork for the development of models to understand macrocycle-biomolecule interactions and for the preparation of macrocycles with designed properties and activities.

  2. Bundle Formation in Biomimetic Hydrogels.

    Science.gov (United States)

    Jaspers, Maarten; Pape, A C H; Voets, Ilja K; Rowan, Alan E; Portale, Giuseppe; Kouwer, Paul H J

    2016-08-08

    Bundling of single polymer chains is a crucial process in the formation of biopolymer network gels that make up the extracellular matrix and the cytoskeleton. This bundled architecture leads to gels with distinctive properties, including a large-pore-size gel formation at very low concentrations and mechanical responsiveness through nonlinear mechanics, properties that are rarely observed in synthetic hydrogels. Using small-angle X-ray scattering (SAXS), we study the bundle formation and hydrogelation process of polyisocyanide gels, a synthetic material that uniquely mimics the structure and mechanics of biogels. We show how the structure of the material changes at the (thermally induced) gelation point and how factors such as concentration and polymer length determine the architecture, and with that, the mechanical properties. The correlation of the gel mechanics and the structural parameters obtained from SAXS experiments is essential in the design of future (synthetic) mimics of biopolymer networks.

  3. Principal bundles the classical case

    CERN Document Server

    Sontz, Stephen Bruce

    2015-01-01

    This introductory graduate level text provides a relatively quick path to a special topic in classical differential geometry: principal bundles.  While the topic of principal bundles in differential geometry has become classic, even standard, material in the modern graduate mathematics curriculum, the unique approach taken in this text presents the material in a way that is intuitive for both students of mathematics and of physics. The goal of this book is to present important, modern geometric ideas in a form readily accessible to students and researchers in both the physics and mathematics communities, providing each with an understanding and appreciation of the language and ideas of the other.

  4. CHEMICALLY MODIFIED FIELD-EFFECT TRANSISTORS - POTENTIOMETRIC AG+ SELECTIVITY OF PVC MEMBRANES BASED ON MACROCYCLIC THIOETHERS

    NARCIS (Netherlands)

    BRZOZKA, Z; COBBEN, PLHM; REINHOUDT, DN; EDEMA, JJH; KELLOGG, RM

    1993-01-01

    A chemically modified field-effect transistor (CHEMFET) with satisfactory Ag+ selectivity is described. The potentiometric Ag+ selectivities of CHEMFETs with plasticized PVC membranes based on macrocyclic thioethers have been determined. All the macrocyclic thioethers tested showed silver response a

  5. Creep rupture of fiber bundles

    DEFF Research Database (Denmark)

    Linga, G.; Ballone, P.; Hansen, Alex

    2015-01-01

    The creep deformation and eventual breaking of polymeric samples under a constant tensile load F is investigated by molecular dynamics based on a particle representation of the fiber bundle model. The results of the virtual testing of fibrous samples consisting of 40000 particles arranged on Nc=4...

  6. Line bundles and flat connections

    Indian Academy of Sciences (India)

    INDRANIL BISWAS; GEORG SCHUMACHER

    2017-06-01

    We prove that there are cocompact lattices $\\Gamma$ in $\\rm SL(2,\\mathbb C)$ with the property that there are holomorphic line bundles $L$ on $\\rm SL(2,\\mathbb C)/ \\Gamma$ with $c_{1}(L) = 0$ such that $L$ does not admit any unitary flat connection.

  7. Vector Bundles over Elliptic Fibrations

    CERN Document Server

    Friedman, R; Witten, Edward; Friedman, Robert; Morgan, John W.; Witten, Edward

    1997-01-01

    This paper gives various methods for constructing vector bundles over elliptic curves and more generally over families of elliptic curves. We construct universal families over generalized elliptic curves via spectral cover methods and also by extensions, and then give a relative version of the construction in families. We give various examples and make Chern class computations.

  8. Macrocyclic Assembly: A Dive into the Pecking Order and Applied Aspects of Multitalented Metallomacrocycles

    Directory of Open Access Journals (Sweden)

    Ashu Chaudhary

    2014-01-01

    Full Text Available To aid in knowledge of macrocyclic complexes and biomedical scientists, we are presenting here a review article with compilation of work done so far along in relation to macrocyclic ligands and their metal complexes. The metal ion chemistry of macrocyclic ligands has now become a major subdivision of coordination chemistry. This overview focuses on developments in design, synthesis, and self-assembly of metal-based architectures and ligands related to macrocyclic chemistry.

  9. Control of olefin geometry in macrocyclic ring-closing metathesis using a removable silyl group.

    Science.gov (United States)

    Wang, Yikai; Jimenez, Miguel; Hansen, Anders S; Raiber, Eun-Ang; Schreiber, Stuart L; Young, Damian W

    2011-06-22

    Introducing a silyl group at one of the internal olefin positions in diolefinic substrates results in E-selective olefin formation in macrocyclic ring-forming metathesis. The application of this method to a range of macrocyclic (E)-alkenylsiloxanes is described. Protodesilylation of alkenylsiloxane products yields novel Z-configured macrocycles.

  10. Quantum principal bundles and corresponding gauge theories

    CERN Document Server

    Durdevic, M

    1995-01-01

    A generalization of classical gauge theory is presented, in the framework of a noncommutative-geometric formalism of quantum principal bundles over smooth manifolds. Quantum counterparts of classical gauge bundles, and classical gauge transformations, are introduced and investigated. A natural differential calculus on quantum gauge bundles is constructed and analyzed. Kinematical and dynamical properties of corresponding gauge theories are discussed.

  11. Strategic and welfare implications of bundling

    DEFF Research Database (Denmark)

    Martin, Stephen

    1999-01-01

    A standard oligopoly model of bundling shows that bundling by a firm with a monopoly over one product has a strategic effect because it changes the substitution relationships between the goods among which consumers choose. Bundling in appropriate proportions is privately profitable, reduces rival......' profits and overall welfare, and may drive rivals from the market...

  12. Higher order jet prolongations type gauge natural bundles over vector bundles

    Directory of Open Access Journals (Sweden)

    Jan Kurek

    2004-05-01

    Full Text Available Let $rgeq 3$ and $mgeq 2$ be natural numbers and $E$ be a vector bundle with $m$-dimensional basis. We find all gauge natural bundles ``similar" to the $r$-jet prolongation bundle $J^rE$ of $E$. We also find all gauge natural bundles ``similar" to the vector $r$-tangent bundle $(J^r_{fl}(E,R_0^*$ of $E$.

  13. Multipath packet switch using packet bundling

    DEFF Research Database (Denmark)

    Berger, Michael Stubert

    2002-01-01

    The basic concept of packet bundling is to group smaller packets into larger packets based on, e.g., quality of service or destination within the packet switch. This paper presents novel applications of bundling in packet switching. The larger packets created by bundling are utilized to extend...... switching capacity by use of parallel switch planes. During the bundling operation, packets will experience a delay that depends on the actual implementation of the bundling and scheduling scheme. Analytical results for delay bounds and buffer size requirements are presented for a specific scheduling...

  14. Macrocycle synthesis by trimerization of boronic acids around a hexaol template, and recognition of polyols by resulting macrocyclic oligoboronic acids.

    Science.gov (United States)

    Stoltenberg, Dennis; Lüning, Ulrich

    2013-08-21

    2,6-Bis(alkenyloxy) substituted arylboronic acids can be cyclotrimerized with the help of a hexaol as a template. First, the boronic acids are assembled by boronic ester formation with hexahydroxy-bicyclo[2.2.2]octane. Next, the resulting triboronates are cyclized by ring-closing metathesis to yield trimacrocycles as diastereomeric E/Z mixtures. Catalytic hydrogenation yields a single saturated trimacrocycle. Cleavage of the boronic ester functions liberates the template and generates a macrocycle with three boronic acid functionalities in endo-orientation. Due to this preorganization, macrocycles with boronic acids in endo-positions are good receptors for polyols. The binding of carbohydrates such as fructose was compared with the uptake of the respective templates into macrocycles with two or three boronic acids in endo-orientation.

  15. Dimensional Measurements of Fresh CANDU Fuel Bundle

    Energy Technology Data Exchange (ETDEWEB)

    Jun, Ji Su; Jo, Chang Keun; Jung, Jong Yeob; Koo, Dae Seo; Cho, Moon Sung [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    2005-07-01

    This paper intends to provide the dimensional measurements of fresh CANDU fuel (37-element) bundle for the estimation of deformation of post-irradiated (PI) bundle. It is expensive and difficult to measure the fretting wear of bearing pad, the element bowing and the waviness of endplate at the two-phase high flow condition (above 24 kg/s) of out-of-reactor test. So, it is recommended to compare the geometry of fresh bundle with that of PI bundle to estimate the integrity of fuel bundle in the CANDU-6 fuel channel with two-phase flow condition. The measurement system has been developed to provide the visual inspection and the dimensional measurements within the accuracy of 10 {mu}m. It is applicable in-air and underwater to the CANDU bundle as well as the CANFLEX bundle. The in-air measurements of the 36 fresh CANDU bundles (S/N: B400892 {approx} B400927) are done by this system from February 2004 to March 2004 in the PHWR fresh fuel storage building of KNFC. These bundles are produced by KNFC manufacturing procedure and are waiting for the delivery to the Wolsong-3 plant, and are planned to load into the proposed test channels. The detail measurements contain the outer rod profile (including the bearing pad), the diameter of bundle, the bowing of bundle, the rod length and the surface profile of end plate (waviness)

  16. Mathematical modelling for nanotube bundle oscillators

    Science.gov (United States)

    Thamwattana, Ngamta; Cox, Barry J.; Hill, James M.

    2009-07-01

    This paper investigates the mechanics of a gigahertz oscillator comprising a nanotube oscillating within the centre of a uniform concentric ring or bundle of nanotubes. The study is also extended to the oscillation of a fullerene inside a nanotube bundle. In particular, certain fullerene-nanotube bundle oscillators are studied, namely C60-carbon nanotube bundle, C60-boron nitride nanotube bundle, B36N36-carbon nanotube bundle and B36N36-boron nitride nanotube bundle. Using the Lennard-Jones potential and the continuum approach, we obtain a relation between the bundle radius and the radii of the nanotubes forming the bundle, as well as the optimum bundle size which gives rise to the maximum oscillatory frequency for both the fullerene and the nanotube bundle oscillators. While previous studies in this area have been undertaken through molecular dynamics simulations, this paper emphasizes the use of applied mathematical modelling techniques which provides considerable insight into the underlying mechanisms. The paper presents a synopsis of the major results derived in detail by the present authors in [1, 2].

  17. Photonic bandgap fiber bundle spectrometer

    CERN Document Server

    Hang, Qu; Syed, Imran; Guo, Ning; Skorobogatiy, Maksim

    2010-01-01

    We experimentally demonstrate an all-fiber spectrometer consisting of a photonic bandgap fiber bundle and a black and white CCD camera. Photonic crystal fibers used in this work are the large solid core all-plastic Bragg fibers designed for operation in the visible spectral range and featuring bandgaps of 60nm - 180nm-wide. 100 Bragg fibers were chosen to have complimentary and partially overlapping bandgaps covering a 400nm-840nm spectral range. The fiber bundle used in our work is equivalent in its function to a set of 100 optical filters densely packed in the area of ~1cm2. Black and white CCD camera is then used to capture spectrally "binned" image of the incoming light at the output facet of a fiber bundle. To reconstruct the test spectrum from a single CCD image we developed an algorithm based on pseudo-inversion of the spectrometer transmission matrix. We then study resolution limit of this spectroscopic system by testing its performance using spectrally narrow test peaks (FWHM 5nm-25nm) centered at va...

  18. Rigid, Conjugated Macrocycles for High Performance Organic Photodetectors.

    Science.gov (United States)

    Zhang, Boyuan; Trinh, M Tuan; Fowler, Brandon; Ball, Melissa; Xu, Qizhi; Ng, Fay; Steigerwald, Michael L; Zhu, X-Y; Nuckolls, Colin; Zhong, Yu

    2016-12-21

    Organic photodetectors (OPDs) are attractive for their high optical absorption coefficient, broad wavelength tunability, and compatibility with lightweight and flexible devices. Here we describe a new molecular design that enables high performance organic photodetectors. We use a rigid, conjugated macrocycle as the electron acceptor in devices to obtain high photocurrent and low dark current. We make a direct comparison between the devices made with the macrocyclic acceptor and an acyclic control molecule; we find that the superior performance of the macrocycle originates from its rigid, conjugated, and cyclic structure. The macrocycle's rigid structure reduces the number of charged defects originating from deformed sp(2) carbons and covalent defects from photo/thermoactivation. With this molecular design, we are able to suppress dark current density while retaining high responsivity in an ultrasensitive nonfullerene OPD. Importantly, we achieve a detectivity of ∼10(14) Jones at near zero bias voltage. This is without the need for extra carrier blocking layers commonly employed in fullerene-based devices. Our devices are comparable to the best fullerene-based photodetectors, and the sensitivity at low working voltages (<0.1 V) is a record for nonfullerene OPDs.

  19. Magnetism in (Semi)Conducting Macrocycles of pi conjugated Polymers

    Science.gov (United States)

    2016-12-09

    estimation of the chain length or the number of repetitive thiophene units, which were for the four samples 18, 25, 33 and 42. The formyl moieties at...leading to radicals , which can associate together. Scheme 5: Synthetic pathway of fully thiophenic bridged macrocycle by oxidative

  20. Flexible macrocycles as versatile supports for catalytically active metal clusters

    Energy Technology Data Exchange (ETDEWEB)

    Ryan, JD; Gagnon, KJ; Teat, SJ; McIntosh, RD

    2016-02-12

    Here we present three structurally diverse clusters stabilised by the same macrocyclic polyphenol; t-butylcalix[8]arene. This work demonstrates the range of conformations the flexible ligand is capable of adopting, highlighting its versatility in metal coordination. In addition, a Ti complex displays activity for the ring-opening polymerisation of lactide

  1. Synthesis of macrocyclic lactones with methoxysulfonyl side chain

    Institute of Scientific and Technical Information of China (English)

    Chuan Jin Hou; Xiao Mei Liang; Jing Ping Wu; Dao Quan Wang

    2008-01-01

    Two representative macrocyclic lactones with methoxysulfonyl side chain (5a and 5b) were synthesized employing Michael addition with acrolein and ring enlargement as the key steps,starting from potassium a-oxocycloalkylsulfonates (1) in total yields of 45 and 57%,respectively.

  2. Synthesis of new diverse macrocycles from diol precursors

    DEFF Research Database (Denmark)

    Madsen, Charlotte Marie; Hansen, Martin; Thrane, Marie V.;

    2010-01-01

    The formation of a library of diverse macrocycles with different ring sizes from two easily accessible building blocks is presented. Reacting diol precursors with electrophilic reagents lead to 17-membered sulfites and 19-membered malonates in 34–79% yield. Double-reductive amination of dialdehyd...

  3. Schiff base oligopyrrolic macrocycles as ligands for lanthanides and actinides

    Energy Technology Data Exchange (ETDEWEB)

    Sessler, Jonathan L. [Department of Chemistry and Biochemistry, Institute for Cellular and Molecular Biology, 1 University Station A5300, University of Texas at Austin, Austin, TX 78712-0165 (United States)]. E-mail: sessler@mail.utexas.edu; Melfi, Patricia J. [Department of Chemistry and Biochemistry, Institute for Cellular and Molecular Biology, 1 University Station A5300, University of Texas at Austin, Austin, TX 78712-0165 (United States); Tomat, Elisa [Department of Chemistry and Biochemistry, Institute for Cellular and Molecular Biology, 1 University Station A5300, University of Texas at Austin, Austin, TX 78712-0165 (United States); Callaway, Wyeth [Department of Chemistry and Biochemistry, Institute for Cellular and Molecular Biology, 1 University Station A5300, University of Texas at Austin, Austin, TX 78712-0165 (United States); Huggins, Michael T. [Department of Chemistry and Biochemistry, Institute for Cellular and Molecular Biology, 1 University Station A5300, University of Texas at Austin, Austin, TX 78712-0165 (United States); Gordon, Pamela L. [C-Chemistry and NMT-Nuclear Materials Technology Divisions, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Webster Keogh, D. [C-Chemistry and NMT-Nuclear Materials Technology Divisions, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Date, Richard W. [Department of Chemistry, University of Exeter, Stocker Road, Exeter EX4 4QD (United Kingdom); Bruce, Duncan W. [Department of Chemistry, University of Exeter, Stocker Road, Exeter EX4 4QD (United Kingdom); Department of Chemistry, University of York, Heslington, YORK YO10 5DD (United Kingdom); Donnio, Bertrand [Institut de Physique et Chimie des Materiaux de Strasbourg (IPCMS), Groupe des Materiaux Organiques (GMO), CNRS-ULP - UMR 7504, 23 rue du Loess BP 43, F-67034 Strasbourg Cedex 2 (France)

    2006-07-20

    The coordination of f-block cations with Schiff base oligopyrrolic macrocycles is discussed. Analysis of the mesophase of a uranyl 2,5-diformylpyrrole-derived expanded porphyrin complex through temperature-dependent X-ray diffraction (XRD) methods has provided evidence for liquid-crystalline properties, and for molecular stacking into columns, arranged in a 2D hexagonal lattice. In separate studies, UV-vis spectral analysis has indicated the formation of three new f-block oligopyrrolic complexes. Addition of neptunyl ([NpO{sub 2}]{sup 2+}) or plutonyl ([PuO{sub 2}]{sup 2+}) chloride salts to the free base of a dipyrromethane-derived Schiff base macrocycle induces an immediate spectral change, namely the growth of a Q-like band at 630 nm. Such changes in the absorption spectra cause a dramatic color change from pale yellow to blue. It is postulated that oxidation of this macrocycle, stimulated by reduction of the metal center, leads to the observed spectral changes. An immediate visible and spectral change is also observed with the reaction of lutetium silylamide (Lu[N(Si(CH{sub 3}){sub 3}){sub 2}]{sub 3}), with a different, tetrapyrrole-containing Schiff base macrocycle. In this case, the formation of a complex with 1:1 metal-to-ligand binding stoichiometry is further supported by MALDI-TOF mass spectrometry.

  4. General frame structures on quantum principal bundles

    CERN Document Server

    Durdevic, M

    1996-01-01

    A noncommutative-geometric generalization of the classical formalism of frame bundles is developed, incorporating into the theory of quantum principal bundles the concept of the Levi-Civita connection. The construction of a natural differential calculus on quantum principal frame bundles is presented, including the construction of the associated differential calculus on the structure group. General torsion operators are defined and analyzed. Illustrative examples are presented.

  5. ACM Bundles on Del Pezzo surfaces

    Directory of Open Access Journals (Sweden)

    Joan Pons-Llopis

    2009-11-01

    Full Text Available ACM rank 1 bundles on del Pezzo surfaces are classified in terms of the rational normal curves that they contain. A complete list of ACM line bundles is provided. Moreover, for any del Pezzo surface X of degree less or equal than six and for any n ≥ 2 we construct a family of dimension ≥ n − 1 of non-isomorphic simple ACM bundles of rank n on X.

  6. Entropy for frame bundle systems and Grassmann bundle systems induced by a diffeomorphism

    Institute of Scientific and Technical Information of China (English)

    SUN; Weniang(孙文祥)

    2002-01-01

    ALiao hyperbolic diffeomorphism has equal measure entropy and topological entropy to that ofits induced systems on frame bundles and Grassmann bundles. This solves a problem Liao posed in 1996 forLiao hyperbolic diffeomorphisms.

  7. Hydraulic characteristics of HANARO fuel bundles

    Energy Technology Data Exchange (ETDEWEB)

    Cho, S.; Chung, H. J.; Chun, S. Y.; Yang, S. K.; Chung, M. K. [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1997-12-31

    This paper presents the hydraulic characteristics measured by using LDV (Laser Doppler Velocimetry) in subchannels of HANARO, KAERI research reactor, fuel bundle. The fuel bundle consists of 18 axially finned rods with 3 spacer grids, which are arranged in cylindrical configuration. The effects of the spacer grids on the turbulent flow were investigated by the experimental results. Pressure drops for each component of the fuel bundle were measured, and the friction factors of fuel bundle and loss coefficients for the spacer grids were estimated from the measured pressure drops. Implications regarding the turbulent thermal mixing were discussed. Vibration test results measured by using laser vibrometer were presented. 9 refs., 12 figs. (Author)

  8. Thermal Hydraulic Performance of Tight Lattice Bundle

    Science.gov (United States)

    Yamamoto, Yasushi; Akiba, Miyuki; Morooka, Shinichi; Shirakawa, Kenetsu; Abe, Nobuaki

    Recently, the reduced moderation spectrum BWR has been studied. The fast neutron spectrum is obtained through triangular tight lattice fuel. However, there are few thermal hydraulic test data and thermal hydraulic correlation applicable to critical power prediction in such a tight lattice bundle. This study aims to enhance the database of the thermal hydraulic performance of the tight lattice bundle whose rod gap is about 1mm. Therefore, thermal hydraulic performance measurement tests of tight lattice bundles for the critical power, the pressure drop and the counter current flow limiting were performed. Moreover, the correlations to evaluate the thermal-hydraulic performance of the tight lattice bundle were developed.

  9. Principal $G$-bundles over elliptic curves

    CERN Document Server

    Friedman, R; Witten, Edward; Friedman, Robert; Morgan, John W.; Witten, Edward

    1997-01-01

    Let $G$ be a simple and simply connected complex Lie group. We discuss the moduli space of holomorphic semistable principal $G$-bundles over an elliptic curve $E$. In particular, we give a new proof of a theorem of Looijenga and Bernshtein-Shvartsman, that the moduli space is a weighted projective space. The method of proof is to study the deformations of certain unstable bundles coming from special maximal parabolic subgroups of $G$. We also discuss the associated automorphism sheaves and universal bundles, as well as the relation between various universal bundles and spectral covers.

  10. Statistical Constitutive Equation of Aramid Fiber Bundles

    Institute of Scientific and Technical Information of China (English)

    熊杰; 顾伯洪; 王善元

    2003-01-01

    Tensile impact tests of aramid (Twaron) fiber bundles were carried om under high strain rates with a wide range of 0. 01/s~1000/s by using MTS and bar-bar tensile impact apparatus. Based on the statistical constitutive model of fiber bundles, statistical constitutive equations of aramid fiber bundles are derived from statistical analysis of test data at different strain rates. Comparison between the theoretical predictions and experimental data indicates statistical constitutive equations fit well with the experimental data, and statistical constitutive equations of fiber bundles at different strain rates are valid.

  11. Jacobi Structures on Affine Bundles

    Institute of Scientific and Technical Information of China (English)

    J. GRABOWSKI; D. IGLESIAS; J. C. MARRERO; E. PADR(O)N; P. URBA(N)SKI

    2007-01-01

    We study affine Jacobi structures (brackets) on an affine bundle π: A→M, i.e. Jacobi brackets that close on affine functions. We prove that if the rank of A is non-zero, there is a one-to- one correspondence between affine Jacobi structures on A and Lie algebroid structures on the vector bundle A+=∪p∈M Aff(Ap, R) of affine functionals. In the case rank A = 0, it is shown that there is a one-to-one correspondence between affins Jacobi structures on A and local Lie algebras on A+. Some examples and applications, also for the linear case, are discussed. For a special type of affine Jacobi structures which are canonically exhibited (strongly-affine or affine-homogeneous Jacobi structures) over a real vector space of finite dimension, we describe the leaves of its characteristic foliation as the orbits of an affine representation. These afline Jacobi structures can be viewed as an analog of the Kostant-Arnold-LiouviUe linear Poisson structure on the dual space of a real finite-dimensional Lie algebra.

  12. Functional materials from self-assembled bis-urea macrocycles.

    Science.gov (United States)

    Shimizu, Linda S; Salpage, Sahan R; Korous, Arthur A

    2014-07-15

    CONSPECTUS: This Account highlights the work from our laboratories on bis-urea macrocycles constructed from two C-shaped spacers and two urea groups. These simple molecular units assembled with high fidelity into columnar structures guided by the three-centered urea hydrogen bonding motif and aryl stacking interactions. Individual columns are aligned and closely packed together to afford functional and homogeneous microporous crystals. This approach allows for precise and rational control over the dimensions of the columnar structure simply by changing the small molecular unit. When the macrocyclic unit lacks a cavity, columnar assembly gives strong pillars. Strong pillars with external functional groups such as basic lone pairs can expand like clays to accept guests between the pillars. Macrocycles that contain sizable interior cavities assemble into porous molecular crystals with aligned, well-defined columnar pores that are accessible to gases and guests. Herein, we examine the optimal design of the macrocyclic unit that leads to columnar assembly in high fidelity and probe the feasibility of incorporating a second functional group within the macrocycles. The porous molecular crystals prepared through the self-assembly of bis-urea macrocycles display surface areas similar to zeolites but lower than MOFs. Their simple one-dimensional channels are well-suited for studying binding, investigating transport, diffusion and exchange, and monitoring the effects of encapsulation on reaction mechanism and product distribution. Guests that complement the size, shape, and polarity of the channels can be absorbed into these porous crystals with repeatable stoichiometry to form solid host-guest complexes. Heating or extraction with an organic solvent enables desorption or removal of the guest and subsequent recovery of the solid host. Further, these porous crystals can be used as containers for the selective [2 + 2] cycloadditions of small enones such as 2-cyclohexenone or 3

  13. Organic spin clusters: macrocyclic-macrocyclic polyarylmethyl polyradicals with very high spin S = 5-13.

    Science.gov (United States)

    Rajca, Andrzej; Wongsriratanakul, Jirawat; Rajca, Suchada

    2004-06-02

    Synthesis and magnetic studies of a new class of organic spin clusters, possessing alternating connectivity of unequal spins, are described. Polyarylmethyl polyether precursors to the spin clusters, with linear and branched connectivity between calix[4]arene-based macrocycles, are prepared via modular, multistep syntheses. Their molecular connectivity and stereoisomerism are analyzed using NMR spectroscopy. The absolute masses (4-10 kDa) are determined by FABMS and GPC/MALS. Small angle neutron scattering (SANS) provides the radii of gyration of 1.2-1.8 nm. The corresponding polyradicals with 15, 22, and 36 triarylmethyls, which are prepared and studied as solutions in tetrahydrofuran-d(8), may be described as S' = 7/2, 1/2, 7/2 spin trimer (average S = 5-6), S' = 7/2, 1/2, 6/2, 1/2, 7/2 spin pentamer (average S = 7-9), and spin nonamer (average S = 11-13), respectively, as determined by SQUID magnetometry and numerical fits to linear combinations of the Brillouin functions. For spin trimer and pentamer, the quantitative magnetization data are fit to new percolation models, based upon random distributions of chemical defects and ferromagnetic vs antiferromagnetic couplings. The value of S = 13 is the highest for an organic molecule.

  14. DINUCLEAR COMPLEXES AS BUILDING BLOCKS FOR TETRA-NUCLEAR MACROCYCLIC COMPLEXES WITH DITHIOLATE MACROCYCLIC LIGAND

    Directory of Open Access Journals (Sweden)

    V. Lozan

    2013-06-01

    Full Text Available A series of novel tri-, tetra- and pentanuclear complexes composed of dinuclear LM units (M=Co, Ni, Zn; L=24-membered macrocyclic hexaaza-dithiophenolate ligand and ferrocenecarboxylate ([CpFeC5H4CO2]ˉ, 1,1’-ferrocenedicarboxy-late ([Fe(C5H4-CO22]2ˉ, acetylene-dicarboxylate, terephthalate, isophthalate, and naphthalene diimide dicarboxylate groups is reported. The complexes, have been synthesized and characterised by UV/Vis-, IR-, NMR-spectroscopy, Cyclovoltammetry, and X-ray crystallography. Each dicarboxylate dianion acts as a quadridentate bridging ligand linking two bioctahedral LM2 units via µ1,3-bridging carboxylate functions to generate discrete dications with a central LM2(O2C-R-CO2M2L core. The magnetic properties of these compounds reveal the presence of weak ferromagnetic exchange interactions between the NiII ions of the dinuclear subunits and negligible coupling across the dicarboxylate bridges.

  15. Principal Bundles on the Projective Line

    Indian Academy of Sciences (India)

    V B Mehta; S Subramanian

    2002-08-01

    We classify principal -bundles on the projective line over an arbitrary field of characteristic ≠ 2 or 3, where is a reductive group. If such a bundle is trivial at a -rational point, then the structure group can be reduced to a maximal torus.

  16. Anatomic Double-bundle ACL Reconstruction

    NARCIS (Netherlands)

    V.M. Schreiber; C.F. van Eck; F.H. Fu

    2010-01-01

    Rupture of the anterior cruciate ligament (ACL) is one of the most frequent forms of knee trauma. The traditional surgical treatment for ACL rupture is single-bundle reconstruction. However, during the past few years there has been a shift in interest toward double-bundle reconstruction to closely r

  17. The Verlinde formula for Higgs bundles

    CERN Document Server

    Andersen, Jørgen Ellegaard; Pei, Du

    2016-01-01

    We propose and prove the Verlinde formula for the quantization of the Higgs bundle moduli spaces and stacks for any simple and simply-connected group. This generalizes the equivariant Verlinde formula for the case of $SU(n)$ proposed previously by the second and third author. We further establish a Verlinde formula for the quantization of parabolic Higgs bundle moduli spaces and stacks.

  18. Solar Thermal Energy Storage in a Photochromic Macrocycle.

    Science.gov (United States)

    Vlasceanu, Alexandru; Broman, Søren L; Hansen, Anne S; Skov, Anders B; Cacciarini, Martina; Kadziola, Anders; Kjaergaard, Henrik G; Mikkelsen, Kurt V; Nielsen, Mogens Brøndsted

    2016-07-25

    The conversion and efficient storage of solar energy is recognized to hold significant potential with regard to future energy solutions. Molecular solar thermal batteries based on photochromic systems exemplify one possible technology able to harness and apply this potential. Herein is described the synthesis of a macrocycle based on a dimer of the dihydroazulene/vinylheptafulvene (DHA/VHF) photo/thermal couple. By taking advantage of conformational strain, this DHA-DHA macrocycle presents an improved ability to absorb and store incident light energy in chemical bonds (VHF-VHF). A stepwise energy release over two sequential ring-closing reactions (VHF→DHA) combines the advantages of an initially fast discharge, hypothetically addressing immediate energy consumption needs, followed by a slow process for consistent, long-term use. This exemplifies another step forward in the molecular engineering and design of functional organic materials towards solar thermal energy storage and release.

  19. Line bundle embeddings for heterotic theories

    Energy Technology Data Exchange (ETDEWEB)

    Groot Nibbelink, Stefan [Muenchen Univ. (Germany). Arnold Sommerfeld Center for Theoretical Physics; Ruehle, Fabian [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2016-03-15

    In heterotic string theories consistency requires the introduction of a non-trivial vector bundle. This bundle breaks the original ten-dimensional gauge groups E{sub 8} x E{sub 8} or SO(32) for the supersymmetric heterotic string theories and SO(16) x SO(16) for the non-supersymmetric tachyon-free theory to smaller subgroups. A vast number of MSSM-like models have been constructed up to now, most of which describe the vector bundle as a sum of line bundles. However, there are several different ways of describing these line bundles and their embedding in the ten-dimensional gauge group. We recall and extend these different descriptions and explain how they can be translated into each other.

  20. Requirements for disordered actomyosin bundle contractility

    CERN Document Server

    Lenz, Martin

    2011-01-01

    Actomyosin contractility is essential for biological force generation, and is well understood in highly ordered structures such as striated muscle. In vitro experiments have shown that non-sarcomeric bundles comprised only of F-actin and myosin thick filaments can also display contractile behavior, which cannot be described by standard muscle models. Here we investigate the microscopic symmetries underlying this process in large non-sarcomeric bundles with long actin filaments. We prove that contractile behavior requires non-identical motors that generate large enough forces to probe the nonlinear elastic behavior of F-actin. A simple disordered bundle model demonstrates a contraction mechanism based on these assumptions and predicts realistic bundle deformations. Recent experimental observations of F-actin buckling in in vitro contractile bundles support our model.

  1. Line bundle embeddings for heterotic theories

    CERN Document Server

    Nibbelink, Stefan Groot

    2016-01-01

    In heterotic theories consistency requires the introduction of a non-trivial vector bundle. This bundle breaks the original ten-dimensional gauge groups E_8 x E_8 or SO(32) for the supersymmetric heterotic theories and SO(16) x SO(16) for the non-supersymmetric tachyon-free theory to smaller subgroups. A vast number of MSSM-like models have been constructed up to now, most of which describe the vector bundle as a sum of line bundles. However, there are several different ways of describing these line bundles and their embedding in the ten-dimensional gauge group. We recall and extend these different descriptions and explain how they can be translated into each other.

  2. Line bundle embeddings for heterotic theories

    Science.gov (United States)

    Nibbelin, Stefan Groot; Ruehle, Fabian

    2016-04-01

    In heterotic string theories consistency requires the introduction of a non-trivial vector bundle. This bundle breaks the original ten-dimensional gauge groups E8 × E8 or SO(32) for the supersymmetric heterotic string theories and SO(16) × SO(16) for the non-supersymmetric tachyon-free theory to smaller subgroups. A vast number of MSSM-like models have been constructed up to now, most of which describe the vector bundle as a sum of line bundles. However, there are several different ways of describing these line bundles and their embedding in the ten-dimensional gauge group. We recall and extend these different descriptions and explain how they can be translated into each other.

  3. Composite spinor bundles in gravitation theory

    CERN Document Server

    Sardanashvily, G

    1995-01-01

    In gravitation theory, the realistic fermion matter is described by spinor bundles associated with the cotangent bundle of a world manifold X. In this case, the Dirac operator can be introduced. There is the 1:1 correspondence between these spinor bundles and the tetrad gravitational fields represented by sections of the quotient \\Si of the linear frame bundle over X by the Lorentz group. The key point lies in the fact that different tetrad fields imply nonequivalent representations of cotangent vectors to X by the Dirac's matrices. It follows that a fermion field must be regarded only in a pair with a certain tetrad field. These pairs can be represented by sections of the composite spinor bundle S\\to\\Si\\to X where values of tetrad fields play the role of parameter coordinates, besides the familiar world coordinates.

  4. Double Fell bundles and Spectral triples

    CERN Document Server

    Martins, Rachel A D

    2007-01-01

    As a natural and canonical extension of Kumjian's Fell bundles over groupoids \\cite{fbg}, we give a definition for a double Fell bundle (a double category) over a double groupoid. We show that finite dimensional double category Fell line bundles tensored with their dual with $S^o$-reality satisfy the finite real spectral triples axioms but not necessarily orientability. This means that these product bundles with noncommutative algebras can be regarded as noncommutative compact manifolds more general than real spectral triples as they are not necessarily orientable. By construction, they unify the noncommutative geometry axioms and hence provide an algebraic enveloping structure for finite spectral triples to give the Dirac operator $D$ new algebraic and geometric structures that are otherwise missing in the transition from Fredholm operator to Dirac operator. The Dirac operator in physical applications as a result becomes less ad hoc. The new noncommutative space we present is a complex line bundle over a dou...

  5. Synthesis of arylenealkyne conjugated macrocycles containing a long alkylene bridge

    Institute of Scientific and Technical Information of China (English)

    Xiaohong CHENG; Sigurd HOEGER

    2008-01-01

    The synthesis of the first two arylenealkyne conjugated macrocycles containing a long alkylene bridge via Glaser coupling of template-directed tetra-acetylenes was reported. Tetraacetylene intermediates with complex structures were constructed rapidly via quadruple Hagihara coupling of monoprotected bisace-tylenes to appropriate tetraiodides and subsequent desilylation. The characterization of such compounds was carried out by NMR, GPC and UV-Vis spectra. Unfortunately, the two compounds were not liquid crystals and had no biaxial nematic mesophase character as expected,

  6. A diversity-oriented synthesis strategy enabling the combinatorial-type variation of macrocyclic peptidomimetic scaffolds.

    Science.gov (United States)

    Isidro-Llobet, Albert; Hadje Georgiou, Kathy; Galloway, Warren R J D; Giacomini, Elisa; Hansen, Mette R; Méndez-Abt, Gabriela; Tan, Yaw Sing; Carro, Laura; Sore, Hannah F; Spring, David R

    2015-04-21

    Macrocyclic peptidomimetics are associated with a broad range of biological activities. However, despite such potentially valuable properties, the macrocyclic peptidomimetic structural class is generally considered as being poorly explored within drug discovery. This has been attributed to the lack of general methods for producing collections of macrocyclic peptidomimetics with high levels of structural, and thus shape, diversity. In particular, there is a lack of scaffold diversity in current macrocyclic peptidomimetic libraries; indeed, the efficient construction of diverse molecular scaffolds presents a formidable general challenge to the synthetic chemist. Herein we describe a new, advanced strategy for the diversity-oriented synthesis (DOS) of macrocyclic peptidomimetics that enables the combinatorial variation of molecular scaffolds (core macrocyclic ring architectures). The generality and robustness of this DOS strategy is demonstrated by the step-efficient synthesis of a structurally diverse library of over 200 macrocyclic peptidomimetic compounds, each based around a distinct molecular scaffold and isolated in milligram quantities, from readily available building-blocks. To the best of our knowledge this represents an unprecedented level of scaffold diversity in a synthetically derived library of macrocyclic peptidomimetics. Cheminformatic analysis indicated that the library compounds access regions of chemical space that are distinct from those addressed by top-selling brand-name drugs and macrocyclic natural products, illustrating the value of our DOS approach to sample regions of chemical space underexploited in current drug discovery efforts. An analysis of three-dimensional molecular shapes illustrated that the DOS library has a relatively high level of shape diversity.

  7. On Harder–Narasimhan Reductions for Higgs Principal Bundles

    Indian Academy of Sciences (India)

    Arijit Dey; R Parthasarathi

    2005-05-01

    The existence and uniqueness of – reduction for the Higgs principal bundles over nonsingular projective variety is shown. We also extend the notion of – reduction for (, )-bundles and ramified -bundles over a smooth curve.

  8. Functional bundles of the medial patellofemoral ligament.

    Science.gov (United States)

    Kang, Hui Jun; Wang, Fei; Chen, Bai Cheng; Su, Yan Ling; Zhang, Zhan Chi; Yan, Chang Bao

    2010-11-01

    The purpose of this study was to explore the anatomy and evaluate the function of the medial patellofemoral ligament (MPFL). Anatomical dissection was performed on 12 fresh-frozen knee specimens. The MPFL is a condensation of capsular fibers, which originates at the medial femoral condyle. It runs transversely and inserts to the medial edge of the patella. With the landmark of the medial femur epicondyle (MFE), the femoral origination was located: just 8.90 ± 3.27 mm proximally and 13.47 ± 3.68 mm posteriorly to the MFE. The most interesting finding in present study was functional bundles of its patellar insertion. Approximately from the femoral origination point, fibers of the MPFL form two relatively concentrated fiber bundles: the inferior-straight bundle and the superior-oblique bundle. The whole length of each was 71.78 ± 5.51 and 73.67 ± 5.40 mm, respectively. The included angle between bundles was 15.1° ± 2.1°. Although the superior-oblique bundle and the inferior-straight bundle run on the patellar MPFL inferiorly and superiorly, respectively, as their name indicates, the two bundles are not entirely separated, which make MPFL one intact structure. The inferior-straight bundle is the main static soft tissue restraints where the superior-oblique bundle associated with vastus medialis obliquus (VMO) is to serve as the main dynamic soft tissue restraints. So this finding may provide the theoretical foundation for the anatomical reconstruction of the MPFL and shed lights on the future researchers.

  9. Kinetically E-selective macrocyclic ring-closing metathesis

    Science.gov (United States)

    Shen, Xiao; Nguyen, Thach T.; Koh, Ming Joo; Xu, Dongmin; Speed, Alexander W. H.; Schrock, Richard R.; Hoveyda, Amir H.

    2017-01-01

    Macrocyclic compounds are central to the development of new drugs, but preparing them can be challenging because of the energy barrier that must be surmounted in order to bring together and fuse the two ends of an acyclic precursor such as an alkene (also known as an olefin). To this end, the catalytic process known as ring-closing metathesis (RCM) has allowed access to countless biologically active macrocyclic organic molecules, even for large-scale production. Stereoselectivity is often critical in such cases: the potency of a macrocyclic compound can depend on the stereochemistry of its alkene; alternatively, one isomer of the compound can be subjected to stereoselective modification (such as dihydroxylation). Kinetically controlled Z-selective RCM reactions have been reported, but the only available metathesis approach for accessing macrocyclic E-olefins entails selective removal of the Z-component of a stereoisomeric mixture by ethenolysis, sacrificing substantial quantities of material if E/Z ratios are near unity. Use of ethylene can also cause adventitious olefin isomerization—a particularly serious problem when the E-alkene is energetically less favoured. Here, we show that dienes containing an E-alkenyl–B(pinacolato) group, widely used in catalytic cross-coupling, possess the requisite electronic and steric attributes to allow them to be converted stereoselectively to E-macrocyclic alkenes. The reaction is promoted by a molybdenum monoaryloxide pyrrolide complex and affords products at a yield of up to 73 per cent and an E/Z ratio greater than 98/2. We highlight the utility of the approach by preparing recifeiolide (a 12-membered-ring antibiotic) and pacritinib (an 18-membered-ring enzyme inhibitor), the Z-isomer of which is less potent than the E-isomer. Notably, the 18-membered-ring moiety of pacritinib—a potent anti-cancer agent that is in advanced clinical trials for treating lymphoma and myelofibrosis—was prepared by RCM carried out at a

  10. Higgs bundles and the real symplectic group

    CERN Document Server

    Gothen, Peter B

    2011-01-01

    We give an overview of the work of Corlette, Donaldson, Hitchin and Simpson leading to the non-abelian Hodge theory correspondence between representations of the fundamental group of a surface and the moduli space of Higgs bundles. We then explain how this can be generalized to a correspondence between character varieties for representations of surface groups in real Lie groups G and the moduli space of G-Higgs bundles. Finally we survey recent joint work with Bradlow, Garc\\'ia-Prada and Mundet i Riera on the moduli space of maximal Sp(2n,R)-Higgs bundles.

  11. Biologically Active Macrocyclic Compounds – from Natural Products to Diversity‐Oriented Synthesis

    DEFF Research Database (Denmark)

    Madsen, Charlotte Marie; Clausen, Mads Hartvig

    2011-01-01

    Macrocyclic compounds are attractive targets when searching for molecules with biological activity. The interest in this compound class is increasing, which has led to a variety of methods for tackling the difficult macrocyclization step in their synthesis. This microreview highlights some recent...

  12. Hydrogen bond templated 1:1 macrocyclization through an olefin metathesis/hydrogenation sequence.

    Science.gov (United States)

    Trita, Andrada Stefania; Roisnel, Thierry; Mongin, Florence; Chevallier, Floris

    2013-07-19

    The construction of pyridine-containing macrocyclic architectures using a nonmetallic template is described. 4,6-Dichlororesorcinol was used as an exotemplate to self-organize two aza-heterocyclic units by OH···N hydrogen bonds. Subsequent sequential double olefin metathesis/hydrogenation reactions employing a single ruthenium-alkylidene precatalyst open access to macrocyclic molecules.

  13. Mobility of Taxol in Microtubule Bundles

    Science.gov (United States)

    Ross, J.

    2003-06-01

    Mobility of taxol inside microtubules was investigated using fluorescence recovery after photobleaching (FRAP) on flow-aligned bundles. Bundles were made of microtubules with either GMPCPP or GTP at the exchangeable site on the tubulin dimer. Recovery times were sensitive to bundle thickness and packing, indicating that taxol molecules are able to move laterally through the bundle. The density of open binding sites along a microtubule was varied by controlling the concentration of taxol in solution for GMPCPP samples. With > 63% sites occupied, recovery times were independent of taxol concentration and, therefore, inversely proportional to the microscopic dissociation rate, k_{off}. It was found that 10*k_{off} (GMPCPP) ~ k_{off} (GTP), consistent with, but not fully accounting for, the difference in equilibrium constants for taxol on GMPCPP and GTP microtubules. With taxol along the microtubule interior is hindered by rebinding events when open sites are within ~7 nm of each other.

  14. Noncommutative principal bundles through twist deformation

    CERN Document Server

    Aschieri, Paolo; Pagani, Chiara; Schenkel, Alexander

    2016-01-01

    We construct noncommutative principal bundles deforming principal bundles with a Drinfeld twist (2-cocycle). If the twist is associated with the structure group then we have a deformation of the fibers. If the twist is associated with the automorphism group of the principal bundle, then we obtain noncommutative deformations of the base space as well. Combining the two twist deformations we obtain noncommutative principal bundles with both noncommutative fibers and base space. More in general, the natural isomorphisms proving the equivalence of a closed monoidal category of modules and its twist related one are used to obtain new Hopf-Galois extensions as twists of Hopf-Galois extensions. A sheaf approach is also considered, and examples presented.

  15. Design requirements of ACR-1000 fuel bundle

    Energy Technology Data Exchange (ETDEWEB)

    Gossain, D.; Reid, P. [Atomic Energy of Canada Limited, Mississauga, Ontario (Canada)

    2008-07-01

    The design process for ACR-1000 fuel bundle is being undertaken in accordance with the CSA standard N286.2. As an element of the process, the design requirements were established early in the design phase and compiled in the ACR-1000 Fuel Design Requirements (DR) document. The ACR-1000 fuel bundle design is being developed to meet these requirements. This paper discusses the sources for the requirements such as the ACR project requirements, the plant specifications and regulatory requirements. It also discusses considerations of reactor design decisions and operational decisions in establishing functional, performance, safety and other design requirements for the fuel bundle. The design requirements for the ACR-1000 fuel bundle are summarized and the relationship of the requirements to the plant states of Normal Operation, Anticipated Operational Occurrences (AOOs) and Design Basis Accidents (DBAs) are discussed. Structure of the document to capture all the requirements in addition to functional, performance and safety requirements is presented. (author)

  16. Bundled Hybrid Offset Riser Global Strength Analysis

    Institute of Scientific and Technical Information of China (English)

    William C.Webster; Zhuang Kang; Wenzhou Liang; Youwei Kang; Liping Sun

    2011-01-01

    Bundled hybrid offset riser(BHOR)global strength analysis,which is more complex than single line offset riser global strength analysis,was carried out in this paper.At first,the equivalent theory is used to deal with BHOR,and then its global strength in manifold cases was analyzed,along with the use of a three-dimensional nonlinear time domain finite element program.So the max bending stress,max circumferential stress,and max axial stress in the BHOR bundle main section(BMS)were obtained,and the values of these three stresses in each riser were obtained through the "stress distribution method".Finally,the Max Von Mises stress in each riser was given and a check was made whether or not they met the demand.This paper provides a reference for strength analysis of the bundled hybrid offset riser and some other bundled pipelines.

  17. Liquid Flow in Shaped Fiber Bundle

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yan; WANG Hua-ping; CHEN Yue-hua

    2006-01-01

    By computation and comparison of the critical spreading coefficient parameter, it was found that shaped fiber bundle is better for wetting. Liquid-air interface tension of liquid arising the shaped fiber bundle body is considered as one critical factor besides liquid viscosity, inertia force and liquid-fiber interface tension. Experimental result simulation demonstrated that the liquid-air interface tension is correlated with the geometric size of the liquid arising in body, φ0 (x) and which is affected by the cross sectional shape of fiber and the radius of single fiber. The shaped fiber bundle model is introduced to investigate liquid flow in fiber assembly. The model is generated based on a random function for stochastic forming of fibers in bundle and it is necessary to combine this fundamental model with physical explanation for investigation of liquid flow in fiber assembly.

  18. Dynamic bi-product bundle pricing problem

    Directory of Open Access Journals (Sweden)

    Rafiei Hamed

    2014-01-01

    Full Text Available This paper addresses bundle pricing problem of two products in a stochastic environment so as to maximize net profit of a retailer. In the considered problem, it is assumed that customers are received upon a Poisson distribution and their demands follow a bi-variant distribution function. Also, it is assumed that products are sold individually or in the form of a bundle, which are offered from an initial stock of the products. To tackle the problem, a stochastic dynamic program is developed in which optimum values of the initial stock and order quantities of every planning period are determined. Moreover, prices of the individual products and their bundle are optimized. Also, the proposed dynamic program tackles bundling/ unbundling decisions taken in every planning period. A numerical example of a two planning period horizon is considered to validate the proposed model.

  19. Effect of Testing Conditions on Fibre-Bundle Tensile Properties Part Ⅰ: Sample Preparation, Bundle Mass and Fibre Alignment of Wool Bundles

    Institute of Scientific and Technical Information of China (English)

    YU Wei-dong; YAN Hao-jing; Ron Postle; Yang Shouren

    2002-01-01

    Due to the effects of samples and testing conditions on fibre-bundle tensile behaviour, it is necessary to investigate the relationships between experimental factors and tensile properties for the fibre-bumdle tensile tester (TENSOR). The effects of bundle sample preparation, fibre bundle mass and fibre alignment have been tested. The experimental results indicated that (1) the low damage in combing and no free-end fibres in the cut bundle are most important for the sample preparation; (2) the reasonable bundle mass is 400- 700tex, but the tensile properties measured should bemodified with the bundle mass because a small amount of bundle mass causes the scatter results, while the larger is the bundle mass, the more difficult to comb fibres parallel and to clamp fibre evenly; and (3) the fibre irregular arrangement forms a slack bundle resulting in interaction between fibres, which will affect the reproducibility and accuracy of the tensile testing.

  20. A Geometric Approach to Noncommutative Principal Bundles

    CERN Document Server

    Wagner, Stefan

    2011-01-01

    From a geometrical point of view it is, so far, not sufficiently well understood what should be a "noncommutative principal bundle". Still, there is a well-developed abstract algebraic approach using the theory of Hopf algebras. An important handicap of this approach is the ignorance of topological and geometrical aspects. The aim of this thesis is to develop a geometrically oriented approach to the noncommutative geometry of principal bundles based on dynamical systems and the representation theory of the corresponding transformation group.

  1. Supporting the Secure Deployment of OSGi Bundles

    OpenAIRE

    Parrend, Pierre; Frénot, Stéphane

    2007-01-01

    International audience; The OSGi platform is a lightweight management layer over a Java virtual machine that makes runtime extensi- bility and multi-application support possible in mobile and constraint environments. This powerfull capability opens a particular attack vector against mobile platforms: the in- stallation of malicious OSGi bundles. The first countermea- sure is the digital signature of the bundles. We developed a tool suite that supports the signature, the publication and the va...

  2. The mechanism of patellamide macrocyclization revealed by the characterization of the PatG macrocyclase domain.

    Science.gov (United States)

    Koehnke, Jesko; Bent, Andrew; Houssen, Wael E; Zollman, David; Morawitz, Falk; Shirran, Sally; Vendome, Jeremie; Nneoyiegbe, Ada F; Trembleau, Laurent; Botting, Catherine H; Smith, Margaret C M; Jaspars, Marcel; Naismith, James H

    2012-08-01

    Peptide macrocycles are found in many biologically active natural products. Their versatility, resistance to proteolysis and ability to traverse membranes has made them desirable molecules. Although technologies exist to synthesize such compounds, the full extent of diversity found among natural macrocycles has yet to be achieved synthetically. Cyanobactins are ribosomal peptide macrocycles encompassing an extraordinarily diverse range of ring sizes, amino acids and chemical modifications. We report the structure, biochemical characterization and initial engineering of the PatG macrocyclase domain of Prochloron sp. from the patellamide pathway that catalyzes the macrocyclization of linear peptides. The enzyme contains insertions in the subtilisin fold to allow it to recognize a three-residue signature, bind substrate in a preorganized and unusual conformation, shield an acyl-enzyme intermediate from water and catalyze peptide bond formation. The ability to macrocyclize a broad range of nonactivated substrates has wide biotechnology applications.

  3. The mechanism of patellamide macrocyclization revealed by the characterization of the PatG macrocyclase domain

    Science.gov (United States)

    Koehnke, Jesko; Bent, Andrew; Houssen, Wael E; Zollman, David; Morawitz, Falk; Shirran, Sally; Vendome, Jeremie; Nneoyiegbe, Ada F; Trembleau, Laurent; Botting, Catherine H; Smith, Margaret C M; Jaspars, Marcel; Naismith, James H

    2012-01-01

    Peptide macrocycles are found in many biologically active natural products. Their versatility, resistance to proteolysis and ability to traverse membranes has made them desirable molecules. Although technologies exist to synthesize such compounds, the full extent of diversity found among natural macrocycles has yet to be achieved synthetically. Cyanobactins are ribosomal peptide macrocycles encompassing an extraordinarily diverse range of ring sizes, amino acids and chemical modifications. We report the structure, biochemical characterization and initial engineering of the PatG macrocyclase domain of Prochloron sp. from the patellamide pathway that catalyzes the macrocyclization of linear peptides. The enzyme contains insertions in the subtilisin fold to allow it to recognize a three-residue signature, bind substrate in a preorganized and unusual conformation, shield an acyl-enzyme intermediate from water and catalyze peptide bond formation. The ability to macrocyclize a broad range of nonactivated substrates has wide biotechnology applications. PMID:22796963

  4. Pyrazine motif containing hexagonal macrocycles: synthesis, characterization, and host-guest chemistry with nitro aromatics.

    Science.gov (United States)

    Bhowmick, Sourav; Chakraborty, Sourav; Das, Atanu; Nallapeta, Sivaramaiah; Das, Neeladri

    2015-09-21

    The synthesis and characterization of cationic two-dimensional metallamacrocycles having a hexagonal shape and cavity are described. Both macrocycles utilize a pyrazine motif containing an organometallic acceptor tecton with platinum(II) centers along with different donor ligands. While one macrocycle is a relatively larger [6 + 6], the other is a relatively smaller [2 + 2] polygon. A unique feature of the smaller ensemble is that it is an irregular polygon in which all six edges are not of equal length. Molecular modeling of these macrocycles confirmed the presence of hexagonal cavities. The ability of these π-electron rich macrocycles to act as potential hosts for relatively electron deficient nitroaromatics (DNT = 2,4-dinitrotoluene and PA = picric acid) has been studied using isothermal titration calorimetry (ITC) as a tool. Molecular dynamics simulation studies were subsequently performed to gain critical insight into the binding interactions between the nitroaromatic guest molecules (PA/DNT) and the ionic macrocycles reported herein.

  5. The posttranslational modification cascade to the thiopeptide berninamycin generates linear forms and altered macrocyclic scaffolds.

    Science.gov (United States)

    Malcolmson, Steven J; Young, Travis S; Ruby, J Graham; Skewes-Cox, Peter; Walsh, Christopher T

    2013-05-21

    Berninamycin is a member of the pyridine-containing thiopeptide class of antibiotics that undergoes massive posttranslational modifications from ribosomally generated preproteins. Berninamycin has a 2-oxazolyl-3-thiazolyl-pyridine core embedded in a 35-atom macrocycle rather than typical trithiazolylpyridine cores embedded in 26-atom and 29-atom peptide macrocycles. We describe the cloning of an 11-gene berninamycin cluster from Streptomyces bernensis UC 5144, its heterologous expression in Streptomyces lividans TK24 and Streptomyces venezuelae ATCC 10712, and detection of variant and incompletely processed scaffolds. Posttranslational maturation in S. lividans of both the wild-type berninamycin prepeptide (BerA) and also a T3A mutant generates macrocyclic compounds as well as linear variants, which have failed to form the pyridine and the macrocycle. Expression of the gene cluster in S. venezuelae generates a variant of the 35-atom skeleton of berninamycin, containing a methyloxazoline in the place of a methyloxazole within the macrocyclic framework.

  6. Is It Complete Left Bundle Branch Block? Just Ablate the Right Bundle.

    Science.gov (United States)

    Ali, Hussam; Lupo, Pierpaolo; Foresti, Sara; De Ambroggi, Guido; Epicoco, Gianluca; Fundaliotis, Angelica; Cappato, Riccardo

    2017-03-01

    Complete left bundle branch block (LBBB) is established according to standard electrocardiographic criteria. However, functional LBBB may be rate-dependent or can perpetuate during tachycardia due to repetitive concealed retrograde penetration of impulses through the contralateral bundle "linking phenomenon." In this brief article, we present two patients with basal complete LBBB in whom ablating the right bundle unmasked the actual antegrade conduction capabilities of the left bundle. These cases highlight intriguing overlap between electrophysiological concepts of complete block, linking, extremely slow, and concealed conduction.

  7. STABILIZATION OF UNUSUAL SUBSTRATE COORDINATION MODES IN DINUCLEAR MACROCYCLIC COMPLEXES

    Directory of Open Access Journals (Sweden)

    Vasile Lozan

    2010-06-01

    Full Text Available The steric protection offered by the macrobinucleating hexaazaditiophenolate ligand (L allows for the preparation of the first stable dinuclear nickel(II borohydride bridged complex, which reacts rapidly with elemental sulphur producing a tetranuclear nickel(II complex [{(LNi2}2(μ-S6]2+ bearing a helical μ4-hexa- sulfide ligand. The [(LCoII 2]2+ fragment have been able to trap a monomethyl orthomolybdate in the binding pocket. Unusual coordination modes of substrate in dinuclear macrocyclic compounds was demonstrated.

  8. Natural and Synthetic Macrocyclic Inhibitors of the Histone Deacetylase Enzymes

    DEFF Research Database (Denmark)

    Maolanon, Alex; Kristensen, Helle; Leman, Luke

    2017-01-01

    Inhibition of histone deacetylase (HDAC) enzymes has emerged as a target for development of cancer chemotherapy. Four compounds have gained approval for clinical use by the Food and Drug Administration (FDA) in the US, and several are currently in clinical trials. However, none of these compounds...... HDAC enzymes may hold an advantage over traditional hydroxamic acid-containing inhibitors, which rely on chelation to the conserved active site zinc ion. Here, we review the literature on macrocyclic HDAC inhibitors obtained from natural sources and structure-activity relationship studies inspired...

  9. 8th International Symposium on Supramolecular and Macrocyclic Chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Davis, Jeffery T. [Univ. of Maryland, College Park, MD (United States)

    2015-09-18

    This report summarizes the 8th International Conference on Supramolecular and Macrocyclic Chemistry (ISMSC-8). DOE funds were used to make it more affordable for students, post-docs and junior faculty to attend the conference by covering their registration costs. The conference was held in Crystal City, VA from July 7-11, 2013. See http://www.indiana.edu/~ismsc8/ for the conference website. ISMSC-8 encompassed the broad scope and interdisciplinary nature of the field. We met our goal to bring together leading scientists in molecular recognition and supramolecular chemistry. New research directions and collaborations resulted this conference. The DOE funding was crucial for us achieving our primary goal.

  10. Twisted Bundle on Noncommutative Space and U(1) Instanton

    CERN Document Server

    Ho, P M

    2000-01-01

    We study the notion of twisted bundles on noncommutative space. Due to theexistence of projective operators in the algebra of functions on thenoncommutative space, there are twisted bundles with non-constant dimension.The U(1) instanton solution of Nekrasov and Schwarz is such an example. As amathematical motivation for not excluding such bundles, we find gaugetransformations by which a bundle with constant dimension can be equivalent toa bundle with non-constant dimension.

  11. LWR nuclear fuel bundle data for use in fuel bundle handling

    Energy Technology Data Exchange (ETDEWEB)

    Weihermiller, W.B.; Allison, G.S.

    1979-09-01

    Although increasing numbers of spent light water reactor (LWR) fuel bundles are moved into storage, no handling equipment is set up to manipulate all of the various types of fuel bundles. This report summarizes fuel bundle information of interest to the designer of such handling equipment. Dimensional descriptions are included with discussions of assembly procedure and manufacturer provisions for handling equipment. No attempt is made to make a complete compilation of dimensional information; the number of fuel bundle designs and design revisions makes it impractical. Because the fuel bundle designs are so varied, any equipment intended for handling all types of bundles will have to be designed with flexibility in mind. Besides the ability to manipulate fuel bundles in space, handling equipment may be required to locate an external surface or to position a cutting operation to avoid breaking a fuel rod pressure boundary. Even with the most sophisticated and flexible handling equipment, some situations will require use of the manufacturers' as-built descriptions of individual fuel bundles.

  12. The 'Visualized' macrocycles: Chemistry and application of fluorophore tagged cyclodextrins.

    Science.gov (United States)

    Benkovics, Gábor; Malanga, Milo; Fenyvesi, Éva

    2017-10-15

    Cyclodextrins are macrocyclic molecules able to form host-guest complexes due to their hydrophobic cavity. Because of their carbohydrate nature they do not absorb light in the UV-vis region (200-800nm), but they can be converted into spectroscopically active compounds via modification with a chromophore unit. Among the chromophores, the group of fluorophores can provide high sensitivity in analytical applications (chemosensing) and low detection limit in optical imaging methods (fluorescent microscopy). Fluorophore-tagged cyclodextrins therefore combine interesting spectroscopic properties with promising supramolecular features which make these conjugates widely applicable in various pharmaceutical fields. The aim of this work is to review the various types of fluorophores which have been used for cyclodextrin tagging, to discuss the synthetic strategies used for the conjugation and to summarize the pharmaceutical applications of these 'visualized' macrocycles including their use in photodynamic therapy. The recent achievements in studying how the fluorophore-appended cyclodextrin derivatives cross biological barriers are also reviewed. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. The histology of retinal nerve fiber layer bundles and bundle defects.

    Science.gov (United States)

    Radius, R L; Anderson, D R

    1979-05-01

    The fiber bundle striations recognized clinically in normal monkey eyes appear to be bundles of axons compartmentalized within glial tunnels formed by Müller's-cell processes, when viewed histologically. The dark boundaries that separate individual bundles are the broadened foot endings of these cells near the inner surface of the retina. Within one week after focal retinal photocoagulation, characteristic fundus changes could be seen in experimental eyes. In histologic sections of the involved retina, there was marked cystic degeneration of the retinal nerve fiber layer. Within one month, atrophy of distal axon segments was complete. With the drop-out of damaged axons and thinning of individual fiber bundles, retinal striations became less prominent. The resulting fundus picture in these experimental eyes is similar to fiber bundle defects that can be seen clinically in various neuro-ophthalmic disorders.

  14. Double template effect in [4 + 4] Schiff base macrocycle formation; an ESI-MS study.

    Science.gov (United States)

    Barreira-Fontecha, Julia; Kulmaczewski, Rafal; Ma, Xiaomei; McKee, Vickie

    2011-12-07

    The mechanism of self-assembly of a polynuclear complex of a [4 + 4] Schiff base iminomethylenediphenolate macrocycle [BaCu(4)(4 + 4)](2+) via a non-macrocyclic dialdehyde intermediate has been followed using ESI-MS of the reaction solutions. Both assembly of the intermediate and Schiff-base condensation with diamine give rise to single products; formation of the intermediate metallacycle is fast but Schiff-base condensation is much slower. Both intermediate complex and macrocyclic product have been structurally characterised.

  15. Tangent bundle formulation of a charged gas

    CERN Document Server

    Sarbach, Olivier

    2013-01-01

    We discuss the relativistic kinetic theory for a simple, collisionless, charged gas propagating on an arbitrary curved spacetime geometry. Our general relativistic treatment is formulated on the tangent bundle of the spacetime manifold and takes advantage of its rich geometric structure. In particular, we point out the existence of a natural metric on the tangent bundle and illustrate its role for the development of the relativistic kinetic theory. This metric, combined with the electromagnetic field of the spacetime, yields an appropriate symplectic form on the tangent bundle. The Liouville vector field arises as the Hamiltonian vector field of a natural Hamiltonian. The latter also defines natural energy surfaces, called mass shells, which turn out to be smooth Lorentzian submanifolds. A simple, collisionless, charged gas is described by a distribution function which is defined on the mass shell and satisfies the Liouville equation. Suitable fibre integrals of the distribution function define observable fie...

  16. Classical Higgs fields on gauge gluon bundles

    Directory of Open Access Journals (Sweden)

    Palese Marcella

    2016-01-01

    Full Text Available Classical Higgs fields and related canonical conserved quantities are defined by invariant variational problems on suitably defined gauge gluon bundles. We consider Lagrangian field theories which are assumed to be invariant with respect to the action of a gauge-natural group. As an illustrative example we exploit the ‘gluon Lagrangian’, i.e. a Yang-Mills Lagrangian on the (1, 1-order gauge-natural bundle of SU(3-principal connections. The kernel of the gauge-natural Jacobi morphism for such a Lagrangian, by inducing a reductive split structure, canonically defines a ‘gluon classical Higgs field’.

  17. Abelian conformal field theory and determinant bundles

    DEFF Research Database (Denmark)

    Andersen, Jørgen Ellegaard; Ueno, K.

    2007-01-01

    Following [10], we study a so-called bc-ghost system of zero conformal dimension from the viewpoint of [14, 16]. We show that the ghost vacua construction results in holomorphic line bundles with connections over holomorphic families of curves. We prove that the curvature of these connections...... are up to a scale the same as the curvature of the connections constructed in [14, 16]. We study the sewing construction for nodal curves and its explicit relation to the constructed connections. Finally we construct preferred holomorphic sections of these line bundles and analyze their behaviour near...

  18. Balance Ability and Proprioception after Single-Bundle, Single-Bundle Augmentation, and Double-Bundle ACL Reconstruction

    Directory of Open Access Journals (Sweden)

    Yubao Ma

    2014-01-01

    Full Text Available Purpose. The present study sought to determine the influences of single-bundle (SB, single-bundle augmentation (SBA, and double-bundle (DB reconstructions on balance ability and proprioceptive function. Methods. 67 patients who underwent a single- or double-bundle ACL reconstruction or a SBA using multistranded autologous hamstring tendons were included in this study with a 1-year follow-up. Body sway and knee kinesthesia (using the threshold to detect passive motion test (TTDPM were measured to indicate balance ability and proprioceptive function, respectively. Additionally, within-subject differences in anterior-posterior stability of the tibia and lower extremity muscle strength were evaluated before and after surgery. Results. At 6 and 12 months after surgery, DB reconstruction resulted in better balance and proprioceptive function than SB reconstruction (P<0.05. Although no significant difference was observed in balance ability or proprioceptive function between the SBA and DB reconstructions, knee stability was significantly better with SBA and DB reconstructions than SB reconstruction (P<0.05. No significant differences were found in quadriceps and hamstrings strength among the three reconstruction techniques. Conclusions. Our findings consider that joint stability, proprioceptive function, and balance ability were superior with SBA and DB reconstructions compared to SB reconstruction at 6 and 12 months after surgery.

  19. Organic Electrofluorescent Materials Using Pyridine-Containing Macrocyclic Compounds

    Institute of Scientific and Technical Information of China (English)

    Tingxi LI; Long FU; Wenwen YU; Renhe HUANG

    2008-01-01

    Novel pyridine-containing macrocyclic compounds, such as 6,12,19,25-tetramethyl-7,11,20,24-dinitrilo-dibenzo[b,m]l,4,12,15-tetra-azacyclodoc osine (TMCD), were synthesized and used as electron transport layer in organic electroluminescent devices. Devices with a structure of glass/indium-tin oxide/arylamine derivative/tris(quinolinolato)aluminum(Ⅲ) (AIq)/TMCD/LiF/AI exhibited green emission from the Alq layer with external quantum efficiency of 0.84% and luminous efficiency of 1.3 lm/W. The derivatives of TMCD were synthesized and characterized as well. These compounds were also found to be useful as the electron-transporting materials in organic electroluminescent devices.

  20. How do the macrocyclic lactones kill filarial nematode larvae?

    Science.gov (United States)

    Wolstenholme, Adrian J; Maclean, Mary J; Coates, Ruby; McCoy, Ciaran J; Reaves, Barbara J

    2016-09-01

    The macrocyclic lactones (MLs) are one of the few classes of drug used in the control of the human filarial infections, onchocerciasis and lymphatic filariasis, and the only one used to prevent heartworm disease in dogs and cats. Despite their importance in preventing filarial diseases, the way in which the MLs work against these parasites is unclear. In vitro measurements of nematode motility have revealed a large discrepancy between the maximum plasma concentrations achieved after drug administration and the amounts required to paralyze worms. Recent evidence has shed new light on the likely functions of the ML target, glutamate-gated chloride channels, in filarial nematodes and supports the hypothesis that the rapid clearance of microfilariae that follows treatment involves the host immune system.

  1. Surface enhanced second harmonic generation from macrocycle, catenane, and rotaxane thin films : Experiments and theory

    NARCIS (Netherlands)

    Arfaoui, [No Value; Bermudez, [No Value; Bottari, G; De Nadai, C; Jalkanen, JP; Kajzar, F; Leigh, DA; Lubomska, M; Mendoza, SM; Niziol, J; Rudolf, P; Zerbetto, F; Arfaoui, Imad; Bermúdez, Verónica; Jalkanen, Jukka-Pekka

    2006-01-01

    Surface enhanced second harmonic generation (SE SHG) experiments on molecular structures, macrocycles, catenanes, and rotaxanes, deposited as monolayers and multilayers by vacuum sublimation on silver, are reported. The measurements show that the molecules form ordered thin films, where the highest

  2. Radical Polymerization of Vinyl Acetate and Methyl Methacrylate Using Organochromium Initiators Complexed with Macrocyclic Polyamines

    Science.gov (United States)

    1994-06-30

    METHYL METHACRYLATE USING ORGANOCHROMIUM REA NTS COMPLEXED WITH MACROCYCLIC A• by Daniela Mardare, Scott Gaynor, Krzysztof Matyjaszewski DTIC Published... Daniela Mardare, Scott Gaynor, Krzysztof Matyjaszewski 7. PERFORMING ORGANIZATION NAME(S) AND ADORESS(ES) a. PERFORMING ORGANIZATION Carnegie Mellon

  3. LANTHANIDE ENHANCE LUMINESCENCE (LEL) WITH ONE AND TWO PHOTON EXCITATION OF QUANTUM DYES LANTHANIDE (III) - MACROCYCLES

    Science.gov (United States)

    Title: Lanthanide Enhance Luminescence (LEL) with one and two photon excitation of Quantum Dyes? Lanthanide(III)-Macrocycles Principal Author:Robert C. Leif, Newport InstrumentsSecondary Authors:Margie C. Becker, Phoenix Flow Systems Al Bromm, Virginia Commonw...

  4. Design, synthesis and biological evaluation of a macrocyclic discodermolide/dictyostatin hybrid.

    Science.gov (United States)

    Paterson, Ian; Gardner, Nicola M

    2007-01-01

    A 22-membered macrocyclic discodermolide/dictyostatin hybrid has been designed and synthesised; biological evaluation against a range of human cancer cell lines revealed significant levels of growth inhibition.

  5. Selective Synthesis of [2+2] Macrocyclic Schiff Bases from Chiral 1,4-Diamines

    Institute of Scientific and Technical Information of China (English)

    ZHU Hai-Bin; HU Da-Hua; DONG Hua-Ze; LI Gen-Xi; GOU Shao-Hua

    2007-01-01

    [2+2] macrocyclic Schiff bases of three kinds have been synthesized from chiral 1,4-diamines by use of different methods. Macrocyclic Schiff bases 1a-1c have been selectively obtained based on a non-templated dilution method from chiral 1,4-diamines a-c and dialdehyde DA1, whereas macrocycles 2a-2c have been selectively produced from reaction of diamines a-c and dialdehyde DA2 in the presence of boric acid as templates. Macrocyclic Schiff bases 3a-3c have been afforded in high selectivity from diamines a-c and dialdehyde DA3 by means of sodium-template. All the titled compounds have been confirmed by 1H NMR and ESI-MS analyses.

  6. Convergent Synthesis of Rigid Macrocycles Containing One and Two Tetrathiafulvalene Units

    DEFF Research Database (Denmark)

    Simonsen, Klaus B.; Thorup, Niels; Becher, Jan

    1997-01-01

    The synthesis of rigid tetrathiafulvalenophanes containing one or two tetrathiafulvalene units is presented, together with a stepwise convergent synthesis of macrocyclic bis-tetrathiafulvalenes via several open dimeric tetrathiafulvalenes. These systems were investigated by cyclic voltammetry...

  7. Heartworms, macrocyclic lactones, and the specter of resistance to prevention in the United States

    National Research Council Canada - National Science Library

    Bowman, Dwight D

    2012-01-01

    In order to provide a background to current concerns relative to the possible resistance of heartworms to macrocyclic lactones, this review summarizes various studies in which lack of efficacies (LOEs...

  8. LANTHANIDE ENHANCE LUMINESCENCE (LEL) WITH ONE AND TWO PHOTON EXCITATION OF QUANTUM DYES LANTHANIDE (III) - MACROCYCLES

    Science.gov (United States)

    Title: Lanthanide Enhance Luminescence (LEL) with one and two photon excitation of Quantum Dyes? Lanthanide(III)-Macrocycles Principal Author:Robert C. Leif, Newport InstrumentsSecondary Authors:Margie C. Becker, Phoenix Flow Systems Al Bromm, Virginia Commonw...

  9. Assembly of macrocycles by zirconocene-mediated, reversible carbon-carbon bond formation.

    Science.gov (United States)

    Gessner, Viktoria H; Tannaci, John F; Miller, Adam D; Tilley, T Don

    2011-06-21

    Macrocyclic compounds have attracted considerable attention in numerous applications, including host-guest chemistry, chemical sensing, catalysis, and materials science. A major obstacle, however, is the limited number of convenient, versatile, and high-yielding synthetic routes to functionalized macrocycles. Macrocyclic compounds have been typically synthesized by ring-closing or condensation reactions, but many of these procedures produce mixtures of oligomers and cyclic compounds. As a result, macrocycle syntheses are often associated with difficult separations and low yields. Some successful approaches that circumvent these problems are based on "self-assembly" processes utilizing reversible bond-forming reactions, but for many applications, it is essential that the resulting macrocycle be built with a strong covalent bond network. In this Account, we describe how zirconocene-mediated reductive couplings of alkynes can provide reversible carbon-carbon bond-forming reactions well-suited for this purpose. Zirconocene coupling of alkenes and alkynes has been used extensively as a source of novel, versatile pathways to functionalized organic compounds. Here, we describe the development of zirconocene-mediated reductive couplings as a highly efficient method for the preparation of macrocycles and cages with diverse compositions, sizes, and shapes. This methodology is based on the reversible, regioselective coupling of alkynes with bulky substituents. In particular, silyl substituents provide regioselective, reversible couplings that place them into the α-positions of the resulting zirconacyclopentadiene rings. According to density functional theory (DFT) calculations and kinetic studies, the mechanism of this coupling involves a stepwise process, whereby an insertion of the second alkyne influences regiochemistry through both steric and electronic factors. Zirconocene coupling of diynes that incorporate silyl substituents generates predictable macrocyclic products

  10. Macrocyclic effects upon isomeric CuIIMII and MIICuII cores. Formation with unsymmetric phenol-based macrocyclic ligands

    Indian Academy of Sciences (India)

    Masami Yonemura; Yuuki Nakamura; Naoki Usuki; Hisashi Okawa

    2000-06-01

    This paper discusses coordination-position isomeric MIICuII and CuIIMII complexes, using unsymmetric dinucleating macrocycles (Lm;n)2- ((L2;2)2-, (L2;3)2- and (L2;4)2- that comprise two 2-(N-methyl)-aminomethyl-6-iminomethyl-4-bromophenonate entities, combined through the ethylene chain ( = 2) between the two amine nitrogens and through the ethylene, trimethylene or tetramethylene chain ( = 2, 3 or 4) between the two imine nitrogens. The macrocycles have dissimilar N(amine)2O2 and N(imine)2O2 metal-binding sites sharing the phenolic oxygens. The reaction of the mononuclear CuII precursors, [Cu(L2;2)], [Cu(L2;2)] and [Cu(L2;2)], with a MII perchlorate and a MII acetate salt formed (acetato)MII CuII complexes:[CoCu(L2;2)(AcO)]ClO4 0 5H2O] (1), [NiCu(L2;2) (AcO)]ClO4 (2), [ZnCu(L2;2((AcO)]ClO4 (3), [CoCu(L2;3)(AcO)]ClO4 0 5H2O (4), [NiCu(L2;3)(AcO)]ClO4 (5), [ZnCu(L2;3)(AcO)]ClO4 0 5H2O (6), [CoCu(L2;4)(AcO)(DMF)]ClO4 (7), [NiCu(L2;4)(AcO)]ClO4 2DMF (8) and [ZnCu(L2;4)(AcO)]ClO4 (9) (the formulation [MM (Lm;n)]2+ means that M resides in the aminic site and M in the iminic site). The site selectivity of the metal ions is demonstrated by X-ray crystallographic studies for 2 MeOH, 3, 5, 7, and 9. An (acetato)CuIIZnII complex, [CuZn(L2;3)(AcO)]ClO4 (10), was obtained by the reaction of [PbCu(L2;3)]-(ClO4)2 with ZnSO4 4H2O, in the presence of sodium acetate. Other complexes of the CuIIMII type were thermodynamically unstable to cause a scrambling of metal ions. The Cu migration from the iminic site to the aminic site in the synthesis of 10 is explained by the `kinetic macrocyclic effect’. The coordination-position isomers, 6 and 10, are differentiated by physicochemical properties.

  11. Computations in intersection rings of flag bundles

    CERN Document Server

    Grayson, Daniel R; Stillman, Michael E

    2012-01-01

    Intersection rings of flag varieties and of isotropic flag varieties are generated by Chern classes of the tautological bundles modulo the relations coming from multiplicativity of total Chern classes. In this paper we describe the Groebner bases of the ideals of relations and give applications to computation of intersections, as implemented in Macaulay2.

  12. Capacity efficiency of recovery request bundling

    DEFF Research Database (Denmark)

    Ruepp, Sarah Renée; Dittmann, Lars; Berger, Michael Stübert

    2010-01-01

    This paper presents a comparison of recovery methods in terms of capacity efficiency. In particular, a method where recovery requests are bundled towards the destination (Shortcut Span Protection) is evaluated against traditional recovery methods. Our simulation results show that Shortcut Span...... Protection uses more capacity than the unbundled related methods, but this is compensated by easier control and management of the recovery actions....

  13. η-Invariant and Flat Vector Bundles

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    We present an alternate definition of the mod Z component of the AtiyahPatodi-Singer η invariant associated to (not necessary unitary) fiat vector bundles, which identifies explicitly its real and imaginary parts. This is done by combining a deformation of flat connections introduced in a previous paper with the analytic continuation procedure appearing in the original article of Atiyah, Parodi and Singer.

  14. Lazarsfeld-Mukai bundles and applications

    CERN Document Server

    Aprodu, Marian

    2012-01-01

    We survey the development of the notion of Lazarsfeld-Mukai bundles together with various applications, from the classification of Mukai manifolds to Brill-Noether theory and syzygies of $K3$ sections. To see these techniques at work, we present a short proof of a result of M. Reid on the existence of elliptic pencils.

  15. Meromorphic Higgs bundles And Related Geometries

    OpenAIRE

    Dalakov, Peter

    2016-01-01

    The present note is mostly a survey on the generalised Hitchin integrable system and moduli spaces of meromorphic Higgs bundles. We also fill minor gaps in the existing literature, outline a calculation of the infinitesimal period map and review briefly some related geometries.

  16. Meromorphic Higgs bundles and related geometries

    Science.gov (United States)

    Dalakov, Peter

    2016-11-01

    The present note is mostly a survey on the generalised Hitchin integrable system and moduli spaces of meromorphic G-Higgs bundles. We also fill minor gaps in the existing literature, outline a calculation of the infinitesimal period map and review some related geometries.

  17. The Hodge bundle on Hurwitz spaces

    NARCIS (Netherlands)

    van der Geer, G.; Kouvidakis, A.

    2011-01-01

    In 2009 Kokotov, Korotkin and Zograf gave in [7] a formula for the class of the Hodge bundle on the Hurwitz space of admissible covers of genus g and degree d of the projective line. They gave an analytic proof of it. In this note we give an algebraic proof and an extension of the result.

  18. Capacity efficiency of recovery request bundling

    DEFF Research Database (Denmark)

    Ruepp, Sarah Renée; Dittmann, Lars; Berger, Michael Stübert

    2010-01-01

    This paper presents a comparison of recovery methods in terms of capacity efficiency. In particular, a method where recovery requests are bundled towards the destination (Shortcut Span Protection) is evaluated against traditional recovery methods. Our simulation results show that Shortcut Span...

  19. A set of homologous hetarylenediyne macrocycles by oxidative acetylene-acetylene coupling.

    Science.gov (United States)

    Opris, Dorina M; Ossenbach, Alexander; Lentz, Dieter; Schlüter, A Dieter

    2008-06-05

    The synthesis of a set of bipyridine-containing macrocycles by oxidative acetylene-acetylene dimerization is described. The cycles are separated by preparative GPC, and the smallest homologue is analyzed by single-crystal X-ray diffraction, which shows a layered structure with channels that are partially filled with parts of the flexible chains of adjacent macrocycles. The cyclic trimer has a D3h symmetry and is a possible candidate for the formation of metal organic supramolecular assemblies on surfaces.

  20. A mesoporous metal–organic framework based on a shape-persistent macrocycle

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Teng-Hao; Popov, Ilya; Chuang, Yu-Chun; Chen, Yu-Sheng; Miljani; #263; , Ognjen Š. (NSRRC); (UC); (Houston)

    2015-08-26

    A mesoporous Zn-based metal–organic framework (MOF) was prepared from a shape-persistent phenylene ethynylene macrocycle functionalized with three –COOH groups. The rigid ligand has a ~ 9 Å wide central cavity which serves as a predesigned pore. The macrocycles [ππ] stack into pairs, with their carboxylate groups connected via three Zn₃O₁₄C₆H₂ clusters. The resulting MOF has a void volume of 86%.

  1. Synthesis, structure and ring-opening polymerization of macrocyclic arylates containing phthalic unit

    Institute of Scientific and Technical Information of China (English)

    姜洪焱; 陈天禄; 邢彦; 林永华; 徐纪平

    1997-01-01

    A series of maerocyclic arylate diraers have been selectively synthesized by an interfacial polyconden-sation of o-phthaloyldichloride with bisphenols A combination of GPC,FAB-MS,1H and 13C NMR unambiguously confirmed the cyclic nature Although single-crystal X-ray analysis of two such macrocycles reveals no severe strain on the cyclic structures,these macrocycles can undergo facile melt polymerization to give high molecular weight polyary-lates.

  2. Pulsed EPR and NMR spectroscopy of paramagnetic iron porphyrinates and related iron macrocycles: how to understand patterns of spin delocalization and recognize macrocycle radicals.

    Science.gov (United States)

    Walker, F Ann

    2003-07-28

    Pulsed EPR spectroscopic techniques, including ESEEM (electron spin echo envelope modulation) and pulsed ENDOR (electron-nuclear double resonance), are extremely useful for determining the magnitudes of the hyperfine couplings of macrocycle and axial ligand nuclei to the unpaired electron(s) on the metal as a function of magnetic field orientation relative to the complex. These data can frequently be used to determine the orientation of the g-tensor and the distribution of spin density over the macrocycle, and to determine the metal orbital(s) containing unpaired electrons and the macrocycle orbital(s) involved in spin delocalization. However, these studies cannot be carried out on metal complexes that do not have resolved EPR signals, as in the case of paramagnetic even-electron metal complexes. In addition, the signs of the hyperfine couplings, which are not determined directly in either ESEEM or pulsed ENDOR experiments, are often needed in order to translate hyperfine couplings into spin densities. In these cases, NMR isotropic (hyperfine) shifts are extremely useful in determining the amount and sign of the spin density at each nucleus probed. For metal complexes of aromatic macrocycles such as porphyrins, chlorins, or corroles, simple rules allow prediction of whether spin delocalization occurs through sigma or pi bonds, and whether spin density on the ligands is of the same or opposite sign as that on the metal. In cases where the amount of spin density on the macrocycle and axial ligands is found to be too large for simple metal-ligand spin delocalization, a macrocycle radical may be suspected. Large spin density on the macrocycle that is of the same sign as that on the metal provides clear evidence of either no coupling or weak ferromagnetic coupling of a macrocycle radical to the unpaired electron(s) on the metal, while large spin density on the macrocycle that is of opposite sign to that on the metal provides clear evidence of antiferromagnetic coupling

  3. Active Hair-Bundle Motility by the Vertebrate Hair Cell

    Science.gov (United States)

    Tinevez, J.-Y.; Martin, P.; Jülicher, F.

    2009-02-01

    The hair bundle is both a mechano-sensory antenna and a force generator that might help the vertebrate hair cell from the inner ear to amplify its responsiveness to small stimuli. To study active hair-bundle motility, we combined calcium iontophoresis with mechanical stimulation of single hair bundles from the bullfrog's sacculus. A hair bundle could oscillate spontaneously, or be quiescent but display non-monotonic movements in response to abrupt force steps. Extracellular calcium changes or static biases to the bundle's position at rest could affect the kinetics of bundle motion and evoke transitions between the different classes of motility. The calcium-dependent location of a bundle's operating point within its nonlinear force-displacement relation controlled the type of movements observed. A unified theoretical description, in which mechanical activity stems from myosin-based adaptation and electro-mechanical feedback by Ca2+, could account for the fast and slow manifestations of active hair-bundle motility.

  4. LUSTERNIK-S CHNIRELMANN CATEGORY AND EMBEDDING FINITE COVERING MAPS, PRINCIPAL G-BUNDLES INTO BUNDLES

    Institute of Scientific and Technical Information of China (English)

    LIULUOFEI

    1996-01-01

    The author proves several embedding theorems for finite covering maps,principal G-bundies into bundles.The main results are 1. Let π:E→X be a finite covering map, and X a connected locally path-connected paracompact space. If cat X≤k, then the finite covering space π:E→X can be embedded into the trivial real k-plane bundle. 2. Let π:E→X be a principal G-bundle over a paracompact space. If there exists a linera action of Gon F(F=R or C)and cat X≤k ,then π:E→X can be embedded into ξ1 … ξn for any F-vector bundles ξi,i=1,…k.

  5. Interplanetary Overlay Network Bundle Protocol Implementation

    Science.gov (United States)

    Burleigh, Scott C.

    2011-01-01

    The Interplanetary Overlay Network (ION) system's BP package, an implementation of the Delay-Tolerant Networking (DTN) Bundle Protocol (BP) and supporting services, has been specifically designed to be suitable for use on deep-space robotic vehicles. Although the ION BP implementation is unique in its use of zero-copy objects for high performance, and in its use of resource-sensitive rate control, it is fully interoperable with other implementations of the BP specification (Internet RFC 5050). The ION BP implementation is built using the same software infrastructure that underlies the implementation of the CCSDS (Consultative Committee for Space Data Systems) File Delivery Protocol (CFDP) built into the flight software of Deep Impact. It is designed to minimize resource consumption, while maximizing operational robustness. For example, no dynamic allocation of system memory is required. Like all the other ION packages, ION's BP implementation is designed to port readily between Linux and Solaris (for easy development and for ground system operations) and VxWorks (for flight systems operations). The exact same source code is exercised in both environments. Initially included in the ION BP implementations are the following: libraries of functions used in constructing bundle forwarders and convergence-layer (CL) input and output adapters; a simple prototype bundle forwarder and associated CL adapters designed to run over an IPbased local area network; administrative tools for managing a simple DTN infrastructure built from these components; a background daemon process that silently destroys bundles whose time-to-live intervals have expired; a library of functions exposed to applications, enabling them to issue and receive data encapsulated in DTN bundles; and some simple applications that can be used for system checkout and benchmarking.

  6. Rapid synthesis of cyclic oligomeric depsipeptides with positional, stereochemical, and macrocycle size distribution control.

    Science.gov (United States)

    Batiste, Suzanne M; Johnston, Jeffrey N

    2016-12-27

    Macrocyclic small molecules are attractive tools in the development of sensors, new materials, and therapeutics. Within early-stage drug discovery, they are increasingly sought for their potential to interact with broad surfaces of peptidic receptors rather than within their narrow folds and pockets. Cyclization of linear small molecule precursors is a straightforward strategy to constrain conformationally mobile motifs, but forging a macrocycle bond typically becomes more difficult at larger ring sizes. We report the development of a general approach to discrete collections of oligomeric macrocyclic depsipeptides using an oligomerization/macrocyclization process governed by a series of Mitsunobu reactions of hydroxy acid monomers. Ring sizes of 18, 24, 30, and 36 are formed in a single reaction from a didepsipeptide, whereas sizes of 24, 36, and 60 result from a tetradepsipeptide. The ring-size selectivity inherent to the approach can be modulated by salt additives that enhance the formation of specific ring sizes. Use of chemical synthesis to prepare the monomers suggests broad access to functionally and stereochemically diverse collections of natural product-like oligodepsipeptide macrocycles. Two cyclodepsipeptide natural products were prepared along with numerous unnatural oligomeric congeners to provide rapid access to discrete collections of complex macrocyclic small molecules from medium (18) to large (60) ring sizes.

  7. Correlation between oxygen adsorption energy and electronic structure of transition metal macrocyclic complexes.

    Science.gov (United States)

    Liu, Kexi; Lei, Yinkai; Wang, Guofeng

    2013-11-28

    Oxygen adsorption energy is directly relevant to the catalytic activity of electrocatalysts for oxygen reduction reaction (ORR). In this study, we established the correlation between the O2 adsorption energy and the electronic structure of transition metal macrocyclic complexes which exhibit activity for ORR. To this end, we have predicted the molecular and electronic structures of a series of transition metal macrocyclic complexes with planar N4 chelation, as well as the molecular and electronic structures for the O2 adsorption on these macrocyclic molecules, using the density functional theory calculation method. We found that the calculated adsorption energy of O2 on the transition metal macrocyclic complexes was linearly related to the average position (relative to the lowest unoccupied molecular orbital of the macrocyclic complexes) of the non-bonding d orbitals (d(z(2)), d(xy), d(xz), and d(yz)) which belong to the central transition metal atom. Importantly, our results suggest that varying the energy level of the non-bonding d orbitals through changing the central transition metal atom and/or peripheral ligand groups could be an effective way to tuning their O2 adsorption energy for enhancing the ORR activity of transition metal macrocyclic complex catalysts.

  8. Smart macrocyclic molecules: induced fit and ultrafast self-sorting inclusion behavior through dynamic covalent chemistry.

    Science.gov (United States)

    Han, Ji-Min; Pan, Jin-Long; Lei, Ting; Liu, Chenjiang; Pei, Jian

    2010-12-10

    A family of macrocycles with oligo(ethylene glycol) chains, 4O, 5O, and 6O, was developed to construct a series of new incorporated macrocycles through dynamic covalent chemistry. These flexible macrocycles exhibited excellent "self-sorting" abilities with diamine compounds, which depended on the "induced-fit" rule. For instance, the host macrocycles underwent conformational modulation to accommodate the diamine guests, affording [1+1] intramolecular addition compounds regardless of the flexibility of the diamine. These macrocycles folded themselves to fit various diamines with different chain length through modulation of the flexible polyether chain, and afforded intramolecular condensation products. However, if the chain of the diamine was too long and rigid, oligomers or polymers were obtained from the mixture of the macromolecule and the diamine. All results demonstrated that inclusion compounds involving conformationally suitable aromatic diamines were thermodynamically favorable candidates in the mixture due to the restriction of the macrocycle size. Furthermore, kinetic and thermodynamic studies of self-sorting behaviors of both mixed 4O-5O and 4O-6O systems were investigated in detail. Finally, theoretical calculations were also employed to further understand such self-sorting behavior, and indicated that the large enthalpy change of H(2)NArArNH(2)@4O is the driving force for the sorting behavior. Our system may provide a model to further understand the principle of biomolecules with high specificity due only to their conformational self-adjusting ability.

  9. Template Syntheses, Crystal Structures and Supramolecular Assembly of Hexaaza Macrocyclic Copper(II) Complexes

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Taehyung; Kim, Ju Chang [Pukyong National Univ., Busan (Korea, Republic of); Lough, Alan J. [Univ. of Toronto, Toronto (Canada)

    2013-06-15

    Two new hexaaza macrocyclic copper(II) complexes were prepared by a template method and structurally characterized. In the solid state, they were self-assembled by intermolecular interactions to form the corresponding supramolecules 1 and 2, respectively. In the structure of 1, the copper(II) macrocycles are bridged by a tp ligand to form a macrocyclic copper(II) dimer. The dimer extends its structure by intermolecular forces such as hydrogen bonds and C-H···π interactions, resulting in the formation of a double stranded 1D supramolecule. In 2, the basic structure is a monomeric copper(II) macrocycle with deprotonated imidazole pendants. An undulated 1D hydrogen bonded array is achieved through hydrogen bonds between imidazole pendants and secondary amines, where the imidazole pendants act as a hydrogen bond acceptor. The 1D hydrogen bonded supramolecular chain is supported by C-H···π interactions between the methyl groups of acetonitrile ligands and imidazole pendants of the copper(II) macrocycles. In both complexes, the introduction of imidazoles to the macrocycle as a pendant plays an important role for the formation of supramolecules, where they act as intermolecular hydrogen bond donors and/or acceptors, C-H···π and π-π interactions.

  10. Bundling Revisited: Substitute Products and Inter-Firm Discounts

    OpenAIRE

    Armstrong, Mark

    2011-01-01

    This paper extends the standard model of bundling to allow products to be substitutes and for products to be supplied by separate sellers. Whether integrated or separate, firms have an incentive to introduce bundling discounts when demand for the bundle is elastic relative to demand for stand-alone products. When products are partial substitutes, this typically gives an integrated firm a greater incentive to offer a bundle discount (relative to the standard model with additive preferences), w...

  11. Holomorphic Vector Bundle on Hopf Manifolds with Abelian Fundamental Groups

    Institute of Scientific and Technical Information of China (English)

    Xiang Yu ZHOU; Wei Ming LIU

    2004-01-01

    Let X be a Hopf manifolds with an Abelian fundamental group. E is a holomorphic vector bundle of rank r with trivial pull-back to W = Cn - {0}. We prove the existence of a non-vanishing section of L(×) E for some line bundle on X and study the vector bundles filtration structure of E. These generalize the results of D. Mall about structure theorem of such a vector bundle E.

  12. A Comparison between Clinical Results of Selective Bundle and Double Bundle Anterior Cruciate Ligament Reconstruction

    Science.gov (United States)

    Yoo, Yon-Sik; Song, Si Young; Yang, Cheol Jung; Ha, Jong Mun; Kim, Yoon Sang

    2016-01-01

    Purpose The purpose of this study was to compare the clinical outcomes of arthroscopic anatomical double bundle (DB) anterior cruciate ligament (ACL) reconstruction with either selective anteromedial (AM) or posterolateral (PL) bundle reconstruction while preserving a relatively healthy ACL bundle. Materials and Methods The authors evaluated 98 patients with a mean follow-up of 30.8±4.0 months who had undergone DB or selective bundle ACL reconstructions. Of these, 34 cases underwent DB ACL reconstruction (group A), 34 underwent selective AM bundle reconstruction (group B), and 30 underwent selective PL bundle reconstructions (group C). These groups were compared with respect to Lysholm and International Knee Documentation Committee (IKDC) score, side-to-side differences of anterior laxity measured by KT-2000 arthrometer at 30 lbs, and stress radiography and Lachman and pivot shift test results. Pre- and post-operative data were objectively evaluated using a statistical approach. Results The preoperative anterior instability measured by manual stress radiography at 90° of knee flexion in group A was significantly greater than that in groups B and C (all pACL tears offers comparable clinical results to DB reconstruction in complete ACL tears. PMID:27401652

  13. VECTOR BUNDLE, KILLING VECTOR FIELD AND PONTRYAGIN NUMBERS

    Institute of Scientific and Technical Information of China (English)

    周建伟

    1991-01-01

    Let E be a vector bundle over a compact Riemannian manifold M. We construct a natural metric on the bundle space E and discuss the relationship between the killing vector fields of E and M. Then we give a proof of the Bott-Baum-Cheeger Theorem for vector bundle E.

  14. Heat exchanger with helical bundles of finned tubes

    Energy Technology Data Exchange (ETDEWEB)

    Eyking, H.J.

    1975-01-23

    The invention applies to a heat exchanger with helical bundles of tubes consisting of finned tubes separated by spacers. The spacers are designed as closed holding cylinders with holding devices for the tube bundles, each ot which surrounds a bundle of tubes. This construction serves to simplify the production process and to enable the use of the heat exchanger at higher loads.

  15. Gauge bundles and Born-Infeld on the noncommutative torus

    NARCIS (Netherlands)

    Hofman, C.; Verlinde, E.

    1998-01-01

    In this paper, we describe non-abelian gauge bundles with magnetic and electric uxes on higher dimensional noncomm utative tori. We give an explicit construction of a large class of bundles with nonzero magnetic 't Hooft uxes. W e discuss Morita equiv alence between these bundles. The action of

  16. QTLs analysis of rice peduncle vascular bundle and panicle traits

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@The vascular bundle in plants plays an important role in transportation of photosynthetic products, mineral nutrients, water, and so on. Significant positive correlations were found between grain yield, panicle traits and the No. Of peduncle vascular bundles. So, it is very important to study the inheritance of peduncle vascular bundle, which is a quantitative trait.

  17. Stability of Picard Bundle Over Moduli Space of Stable Vector Bundles of Rank Two Over a Curve

    Indian Academy of Sciences (India)

    Indranil Biswas; Tomás L Gómez

    2001-08-01

    Answering a question of [BV] it is proved that the Picard bundle on the moduli space of stable vector bundles of rank two, on a Riemann surface of genus at least three, with fixed determinant of odd degree is stable.

  18. Productivity and costs of slash bundling in Nordic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Kaerhae, K.; Vartiamaeki, T. [Metsaeteho Oy, P.O. Box 101, FI-00171 Helsinki (Finland)

    2006-12-15

    The number of slash bundlers and the volume of slash bundling have been rapidly increasing during the last few years in Finland. However, no comprehensive time or follow-up studies have been carried out on slash bundling technology in Finland or in any other country. Metsateho Oy carried out studies on the productivity and costs of slash bundling in different Nordic recovering conditions. The study methods included both time and follow-up studies. Data were collected during the summer and winter period primarily in Norway spruce (Picea abies L. Karst.) dominated clear cutting sites. The bundling techniques performed by different types of bundler (Fiberpac 370, Timberjack 1490D, Pika RS 2000, Valmet WoodPac) were studied. The average productivity of slash bundling was 18.1 bundles per operating (E{sub 15}, including delays shorter than 15min) hour with the Timberjack 1490D and Fiberpac 370 bundlers in the follow-up study. The operator of the slash bundler had the greatest effect on the productivity of bundling. The prerequisite for increased bundling volumes is a reduction in the costs of the most expensive sub-stage of the bundling supply chain, i.e. bundling itself. This requires improved recovery conditions at bundling sites, increased bundling productivity, larger sized bundles, and the execution of bundling operations in two work shifts using an efficient bundler and effective operator working methods. Implementation of these development measures will bring the bundling supply chain up to a speed that makes it the most competitive supply chain for forest chips in terms of total supply costs for long-distance transportation distances of more than 60km. (author)

  19. Bundling of harvesting residues and whole-trees and the treatment of bundles; Hakkuutaehteiden ja kokopuiden niputus ja nippujen kaesittely

    Energy Technology Data Exchange (ETDEWEB)

    Kaipainen, H.; Seppaenen, V.; Rinne, S.

    1996-12-31

    The conditions on which the bundling of the harvesting residues from spruce regeneration fellings would become profitable were studied. The calculations showed that one of the most important features was sufficient compaction of the bundle, so that the portion of the wood in the unit volume of the bundle has to be more than 40 %. The tests showed that the timber grab loader of farm tractor was insufficient for production of dense bundles. The feeding and compression device of the prototype bundler was constructed in the research and with this device the required density was obtained.The rate of compaction of the dry spruce felling residues was about 40 % and that of the fresh residues was more than 50 %. The comparison between the bundles showed that the calorific value of the fresh bundle per unit volume was nearly 30 % higher than that of the dry bundle. This means that the treatment of the bundles should be done of fresh felling residues. Drying of the bundles succeeded well, and the crushing and chipping tests showed that the processing of the bundles at the plant is possible. The treatability of the bundles was also excellent. By using the prototype, developed in the research, it was possible to produce a bundle of the fresh spruce harvesting residues, the diameter of which was about 50 cm and the length about 3 m, and the rate of compaction over 50 %. By these values the reduction target of the costs is obtainable

  20. Phase Slips in Oscillatory Hair Bundles

    Science.gov (United States)

    Roongthumskul, Yuttana; Shlomovitz, Roie; Bruinsma, Robijn; Bozovic, Dolores

    2013-01-01

    Hair cells of the inner ear contain an active amplifier that allows them to detect extremely weak signals. As one of the manifestations of an active process, spontaneous oscillations arise in fluid immersed hair bundles of in vitro preparations of selected auditory and vestibular organs. We measure the phase-locking dynamics of oscillatory bundles exposed to low-amplitude sinusoidal signals, a transition that can be described by a saddle-node bifurcation on an invariant circle. The transition is characterized by the occurrence of phase slips, at a rate that is dependent on the amplitude and detuning of the applied drive. The resultant staircase structure in the phase of the oscillation can be described by the stochastic Adler equation, which reproduces the statistics of phase slip production. PMID:25167040

  1. Care bundles reduce readmissions for COPD.

    Science.gov (United States)

    Matthews, Healther; Tooley, Cathy; Nicholls, Carol; Lindsey-Halls, Anna

    In 2011, the respiratory nursing team at the James Paget University Hospital Foundation Trust were considering introducing a discharge care bundle for patients admitted with an acute exacerbation of chronic obstructive pulmonary disease. At the same time, the trust was asking for applications for Commissioning for Quality and Innovation schemes (CQUINs). These are locally agreed packages of quality improvement goals and indicators, which, if achieved in total, enable the provider to earn its full CQUIN payment. A CQUIN scheme should address the three domains of quality, safety and effectiveness, patient experience and also show innovation. This article discusses how the care bundle was introduced and how, over a 12-month period, it showed tangible results in improving the care pathway for COPD patients as well as reducing readmissions and saving a significant amount of money.

  2. Emitters of N-photon bundles.

    Science.gov (United States)

    Muñoz, C Sánchez; Del Valle, E; Tudela, A González; Müller, K; Lichtmannecker, S; Kaniber, M; Tejedor, C; Finley, J J; Laussy, F P

    2014-07-01

    Controlling the ouput of a light emitter is one of the basic tasks of photonics, with landmarks such as the laser and single-photon sources. The development of quantum applications makes it increasingly important to diversify the available quantum sources. Here, we propose a cavity QED scheme to realize emitters that release their energy in groups, or "bundles" of N photons, for integer N. Close to 100% of two-photon emission and 90% of three-photon emission is shown to be within reach of state of the art samples. The emission can be tuned with system parameters so that the device behaves as a laser or as a N-photon gun. The theoretical formalism to characterize such emitters is developed, with the bundle statistics arising as an extension of the fundamental correlation functions of quantum optics. These emitters will be useful for quantum information processing and for medical applications.

  3. Client Provider Collaboration for Service Bundling

    Directory of Open Access Journals (Sweden)

    LETIA, I. A.

    2008-04-01

    Full Text Available The key requirement for a service industry organization to reach competitive advantages through product diversification is the existence of a well defined method for building service bundles. Based on the idea that the quality of a service or its value is given by the difference between expectations and perceptions, we draw the main components of a frame that aims to support the client and the provider agent in an active collaboration meant to co-create service bundles. Following e3-value model, we structure the supporting knowledge around the relation between needs and satisfying services. We deal with different perspectives about quality through an ontological extension of Value Based Argumentation. The dialog between the client and the provider takes the form of a persuasion whose dynamic object is the current best configuration. Our approach for building service packages is a demand driven approach, allowing progressive disclosure of private knowledge.

  4. Non-abelian higher gauge theory and categorical bundle

    Science.gov (United States)

    Viennot, David

    2016-12-01

    A gauge theory is associated with a principal bundle endowed with a connection permitting to define horizontal lifts of paths. The horizontal lifts of surfaces cannot be defined into a principal bundle structure. An higher gauge theory is an attempt to generalize the bundle structure in order to describe horizontal lifts of surfaces. A such attempt is particularly difficult for the non-abelian case. Some structures have been proposed to realize this goal (twisted bundle, gerbes with connection, bundle gerbe, 2-bundle). Each of them uses a category in place of the total space manifold of the usual principal bundle structure. Some of them replace also the structure group by a category (more precisely a Lie crossed module viewed as a category). But the base space remains still a simple manifold (possibly viewed as a trivial category with only identity arrows). We propose a new principal categorical bundle structure, with a Lie crossed module as structure groupoid, but with a base space belonging to a bigger class of categories (which includes non-trivial categories), that we called affine 2-spaces. We study the geometric structure of the categorical bundles built on these categories (which are a more complicated structure than the 2-bundles) and the connective structures on these bundles. Finally we treat an example interesting for quantum dynamics which is associated with the Bloch wave operator theory.

  5. Electron transfer reactions of macrocyclic compounds of cobalt

    Energy Technology Data Exchange (ETDEWEB)

    Heckman, R.A.

    1978-08-01

    The kinetics and mechanisms of reduction of H/sub 2/O/sub 2/, Br/sub 2/, and I/sub 2/ by various macrocyclic tetraaza complexes of cobalt(II), including Vitamin B/sub 12r/, were studied. The synthetic macrocycles studied were all 14-membered rings which varied in the degree of unsaturation,substitution of methyl groups on the periphery of the ring, and substitution within the ring itself. Scavenging experiments demonstrated that the reductions of H/sub 2/O/sub 2/ produce free hydroxyl radicals only in the case of Co((14)ane)/sup 2 +/ but with none of the others. In the latter instances apparently H/sub 2/O/sub 2/ simultaneously oxidizes the metal center and the ligand. The reductions of Br/sub 2/ and I/sub 2/ produce an aquohalocobalt(III) product for all reductants (except B/sub 12r/ + Br/sub 2/, which was complicated by bromination of the corrin ring). The mechanism of halogen reduction was found to involve rate-limiting inner-sphere electron transfer from cobalt to halogen to produce a dihalide anion coordinated to the cobalt center. This intermediate subsequently decomposes in rapid reactions to halocobalt(III) and halogen atom species or reacts with another cobalt(II) center to give two molecules of halocobalt(III). The reductions of halomethylcobaloximes and related compounds and diamminecobaloxime by Cr/sup 2 +/ were also studied. The reaction was found to be biphasic in all cases with the reaction products being halomethane (for the halomethylcobaloximes), Co/sup 2 +/ (in less than 100 percent yield), a Cr(III)-dimethylglyoxime species, a small amount of free dmgH/sub 2/, and a highly-charged species containing both cobalt and chromium. The first-stage reaction occurs with a stoichiometry of 1:1 producing an intermediate with an absorption maximum at 460 nm for all starting reagents. The results were interpreted in terms of inner-sphere coordination of the cobaloxime to the Cr(II) and electron transfer through the oxime N-O bond.

  6. [Tl(III)(dota)](-): An Extraordinarily Robust Macrocyclic Complex.

    Science.gov (United States)

    Fodor, Tamás; Bányai, István; Bényei, Attila; Platas-Iglesias, Carlos; Purgel, Mihály; Horváth, Gábor L; Zékány, László; Tircsó, Gyula; Tóth, Imre

    2015-06-01

    The X-ray structure of {C(NH2)3}[Tl(dota)]·H2O shows that the Tl(3+) ion is deeply buried in the macrocyclic cavity of the dota(4-) ligand (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate) with average Tl-N and Tl-O distances of 2.464 and 2.365 Å, respectively. The metal ion is directly coordinated to the eight donor atoms of the ligand, which results in a twisted square antiprismatic (TSAP') coordination around Tl(3+). A multinuclear (1)H, (13)C, and (205)Tl NMR study combined with DFT calculations confirmed the TSAP' structure of the complex in aqueous solution, which exists as the Λ(λλλλ)/Δ(δδδδ) enantiomeric pair. (205)Tl NMR spectroscopy allowed the protonation constant associated with the protonation of the complex according to [Tl(dota)](-) + H(+) ⇆ [Tl(Hdota)] to be determined, which turned out to be pK(H)Tl(dota) = 1.4 ± 0.1. [Tl(dota)](-) does not react with Br(-), even when using an excess of the anion, but it forms a weak mixed complex with cyanide, [Tl(dota)](-) + CN(-) ⇆ [Tl(dota)(CN)](2-), with an equilibrium constant of Kmix = 6.0 ± 0.8. The dissociation of the [Tl(dota)](-) complex was determined by UV-vis spectrophotometry under acidic conditions using a large excess of Br(-), and it was found to follow proton-assisted kinetics and to take place very slowly (∼10 days), even in 1 M HClO4, with the estimated half-life of the process being in the 10(9) h range at neutral pH. The solution dynamics of [Tl(dota)](-) were investigated using (13)C NMR spectroscopy and DFT calculations. The (13)C NMR spectra recorded at low temperature (272 K) point to C4 symmetry of the complex in solution, which averages to C4v as the temperature increases. This dynamic behavior was attributed to the Λ(λλλλ) ↔ Δ(δδδδ) enantiomerization process, which involves both the inversion of the macrocyclic unit and the rotation of the pendant arms. According to our calculations, the arm-rotation process limits the Λ(λλλλ) ↔

  7. Dynamic covalent chemistry approaches toward macrocycles, molecular cages, and polymers.

    Science.gov (United States)

    Jin, Yinghua; Wang, Qi; Taynton, Philip; Zhang, Wei

    2014-05-20

    The current research in the field of dynamic covalent chemistry includes the study of dynamic covalent reactions, catalysts, and their applications. Unlike noncovalent interactions utilized in supramolecular chemistry, the formation/breakage of covalent bonding has slower kinetics and usually requires the aid of a catalyst. Catalytic systems that enable efficient thermodynamic equilibrium are thus essential. In this Account, we describe the development of efficient catalysts for alkyne metathesis, and discuss the application of dynamic covalent reactions (mainly imine, olefin, and alkyne metathesis) in the development of organic functional materials. Alkyne metathesis is an emerging dynamic covalent reaction that offers robust and linear acetylene linkages. By introducing a podand motif into the catalyst ligand design, we have developed a series of highly active and robust alkyne metathesis catalysts, which, for the first time, enabled the one-step covalent assembly of ethynylene-linked functional molecular cages. Imine chemistry and olefin metathesis are among the most well-established reversible reactions, and have also been our main synthetic tools. Various shape-persistent macrocycles and covalent organic polyhedrons have been efficiently constructed in one-step through dynamic imine chemistry and olefin metathesis. The geometrical features and solubilizing groups of the building blocks as well as the reaction kinetics have significant effect on the outcome of a covalent assembly process. More recently, we explored the orthogonality of imine and olefin metatheses, and successfully synthesized heterosequenced macrocycles and molecular cages through one-pot orthogonal dynamic covalent chemistry. In addition to discrete molecular architectures, functional polymeric materials can also be accessed through dynamic covalent reactions. Defect-free solution-processable conjugated polyaryleneethynylenes and polydiacetylenes have been prepared through alkyne metathesis

  8. Quantum principal bundles and their characteristic classes

    CERN Document Server

    Durdevic, M

    1996-01-01

    A brief exposition of the general theory of characteristic classes of quantum principal bundles is given. The theory of quantum characteristic classes incorporates ideas of classical Weil theory into the conceptual framework of non-commutative differential geometry. A purely cohomological interpretation of the Weil homomorphism is given, together with a standard geometrical interpretation via quantum invariant polynomials. A natural spectral sequence is described. Some quantum phenomena appearing in the formalism are discussed.

  9. Uncovering ecosystem service bundles through social preferences.

    Directory of Open Access Journals (Sweden)

    Berta Martín-López

    Full Text Available Ecosystem service assessments have increasingly been used to support environmental management policies, mainly based on biophysical and economic indicators. However, few studies have coped with the social-cultural dimension of ecosystem services, despite being considered a research priority. We examined how ecosystem service bundles and trade-offs emerge from diverging social preferences toward ecosystem services delivered by various types of ecosystems in Spain. We conducted 3,379 direct face-to-face questionnaires in eight different case study sites from 2007 to 2011. Overall, 90.5% of the sampled population recognized the ecosystem's capacity to deliver services. Formal studies, environmental behavior, and gender variables influenced the probability of people recognizing the ecosystem's capacity to provide services. The ecosystem services most frequently perceived by people were regulating services; of those, air purification held the greatest importance. However, statistical analysis showed that socio-cultural factors and the conservation management strategy of ecosystems (i.e., National Park, Natural Park, or a non-protected area have an effect on social preferences toward ecosystem services. Ecosystem service trade-offs and bundles were identified by analyzing social preferences through multivariate analysis (redundancy analysis and hierarchical cluster analysis. We found a clear trade-off among provisioning services (and recreational hunting versus regulating services and almost all cultural services. We identified three ecosystem service bundles associated with the conservation management strategy and the rural-urban gradient. We conclude that socio-cultural preferences toward ecosystem services can serve as a tool to identify relevant services for people, the factors underlying these social preferences, and emerging ecosystem service bundles and trade-offs.

  10. Uncontrolled inexact information within bundle methods

    OpenAIRE

    Malick, Jérôme; Welington De Oliveira, ·; Zaourar-Michel, Sofia

    2016-01-01

    International audience; We consider convex nonsmooth optimization problems where additional information with uncontrolled accuracy is readily available. It is often the case when the objective function is itself the output of an optimization solver, as for large-scale energy optimization problems tackled by decomposition. In this paper, we study how to incorporate the uncontrolled linearizations into (proximal and level) bundle algorithms in view of generating better iterates and possibly acc...

  11. On Complex Supermanifolds with Trivial Canonical Bundle

    CERN Document Server

    Groeger, Josua

    2016-01-01

    We give an algebraic characterisation for the triviality of the canonical bundle of a complex supermanifold in terms of a certain Batalin-Vilkovisky superalgebra structure. As an application, we study the Calabi-Yau case, in which an explicit formula in terms of the Levi-Civita connection is achieved. Our methods include the use of complex integral forms and the recently developed theory of superholonomy.

  12. Uncovering Ecosystem Service Bundles through Social Preferences

    Science.gov (United States)

    Martín-López, Berta; Iniesta-Arandia, Irene; García-Llorente, Marina; Palomo, Ignacio; Casado-Arzuaga, Izaskun; Amo, David García Del; Gómez-Baggethun, Erik; Oteros-Rozas, Elisa; Palacios-Agundez, Igone; Willaarts, Bárbara; González, José A.; Santos-Martín, Fernando; Onaindia, Miren; López-Santiago, Cesar; Montes, Carlos

    2012-01-01

    Ecosystem service assessments have increasingly been used to support environmental management policies, mainly based on biophysical and economic indicators. However, few studies have coped with the social-cultural dimension of ecosystem services, despite being considered a research priority. We examined how ecosystem service bundles and trade-offs emerge from diverging social preferences toward ecosystem services delivered by various types of ecosystems in Spain. We conducted 3,379 direct face-to-face questionnaires in eight different case study sites from 2007 to 2011. Overall, 90.5% of the sampled population recognized the ecosystem’s capacity to deliver services. Formal studies, environmental behavior, and gender variables influenced the probability of people recognizing the ecosystem’s capacity to provide services. The ecosystem services most frequently perceived by people were regulating services; of those, air purification held the greatest importance. However, statistical analysis showed that socio-cultural factors and the conservation management strategy of ecosystems (i.e., National Park, Natural Park, or a non-protected area) have an effect on social preferences toward ecosystem services. Ecosystem service trade-offs and bundles were identified by analyzing social preferences through multivariate analysis (redundancy analysis and hierarchical cluster analysis). We found a clear trade-off among provisioning services (and recreational hunting) versus regulating services and almost all cultural services. We identified three ecosystem service bundles associated with the conservation management strategy and the rural-urban gradient. We conclude that socio-cultural preferences toward ecosystem services can serve as a tool to identify relevant services for people, the factors underlying these social preferences, and emerging ecosystem service bundles and trade-offs. PMID:22720006

  13. Uncovering ecosystem service bundles through social preferences

    OpenAIRE

    Berta Martín-López; Irene Iniesta-Arandia; Marina García-Llorente; Ignacio Palomo; Izaskun Casado-Arzuaga; David García Del Amo; Erik Gómez-Baggethun; Elisa Oteros-Rozas; Igone Palacios-Agundez; Bárbara Willaarts; González, José A.; Fernando Santos-Martín; Miren Onaindia; Cesar López-Santiago; Carlos Montes

    2012-01-01

    11 p. Ecosystem service assessments have increasingly been used to support environmental management policies, mainly based on biophysical and economic indicators. However, few studies have coped with the social-cultural dimension of ecosystem services, despite being considered a research priority. We examined how ecosystem service bundles and trade-offs emerge from diverging social preferences toward ecosystem services delivered by various types of ecosystems in Spain. We conducted 3,379 d...

  14. Deformations of Fell bundles and twisted graph algebras

    Science.gov (United States)

    Raeburn, Iain

    2016-11-01

    We consider Fell bundles over discrete groups, and the C*-algebra which is universal for representations of the bundle. We define deformations of Fell bundles, which are new Fell bundles with the same underlying Banach bundle but with the multiplication deformed by a two-cocycle on the group. Every graph algebra can be viewed as the C*-algebra of a Fell bundle, and there are are many cocycles of interest with which to deform them. We thus obtain many of the twisted graph algebras of Kumjian, Pask and Sims. We demonstate the utility of our approach to these twisted graph algebras by proving that the deformations associated to different cocycles can be assembled as the fibres of a C*-bundle.

  15. Bundling harvester; Harvennuspuun automaattisen nippukorjausharvesterin kehittaeminen

    Energy Technology Data Exchange (ETDEWEB)

    Koponen, K. [Eko-Log Oy, Kuopio (Finland)

    1997-12-01

    The starting point of the project was to design and construct, by taking the silvicultural point of view into account, a harvesting and processing system especially for energy-wood, containing manually driven bundling harvester, automating of the harvester, and automated loading. The equipment forms an ideal method for entrepreneur`s-line harvesting. The target is to apply the system also for owner`s-line harvesting. The profitability of the system promotes the utilisation of the system in both cases. The objectives of the project were: to construct a test equipment and prototypes for all the project stages, to carry out terrain and strain tests in order to examine the usability and durability, as well as the capacity of the machine, to test the applicability of the Eko-Log system in simultaneous harvesting of energy and pulp woods, and to start the marketing and manufacturing of the products. The basic problems of the construction of the bundling harvester have been solved using terrain-tests. The prototype machine has been shown to be operable. Loading of the bundles to form sufficiently economically transportable loads has been studied, and simultaneously, the branch-biomass has been tried to be utilised without loosing the profitability of transportation. The results have been promising, and will promote the profitable utilisation of wood-energy. (orig.)

  16. Development of Strengthened Bundle High Temperature Superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Lue, J.W.; Lubell, M.S. [Oak Ridge National Lab., TN (United States); Demko, J.A. [Oak Ridge Inst. for Science and Education, TN (United States); Tomsic, M. [Plastronic, Inc., Troy, OH (United States); Sinha, U. [Southwire Company, Carollton, GA (United States)

    1997-12-31

    In the process of developing high temperature superconducting (HTS) transmission cables, it was found that mechanical strength of the superconducting tape is the most crucial property that needs to be improved. It is also desirable to increase the current carrying capacity of the conductor so that fewer layers are needed to make the kilo-amp class cables required for electric utility usage. A process has been developed by encapsulating a stack of Bi-2223/Ag tapes with a silver or non-silver sheath to form a strengthened bundle superconductor. This process was applied to HTS tapes made by the Continuous Tube Forming and Filling (CTFF) technique pursued by Plastronic Inc. and HTS tapes obtained from other manufacturers. Conductors with a bundle of 2 to 6 HTS tapes have been made. The bundled conductor is greatly strengthened by the non-silver sheath. No superconductor degradation as compared to the sum of the original critical currents of the individual tapes was seen on the finished conductors.

  17. An analytical fiber bundle model for pullout mechanics of root bundles

    Science.gov (United States)

    Cohen, D.; Schwarz, M.; Or, D.

    2011-09-01

    Roots in soil contribute to the mechanical stability of slopes. Estimation of root reinforcement is challenging because roots form complex biological networks whose geometrical and mechanical characteristics are difficult to characterize. Here we describe an analytical model that builds on simple root descriptors to estimate root reinforcement. Root bundles are modeled as bundles of heterogeneous fibers pulled along their long axes neglecting root-soil friction. Analytical expressions for the pullout force as a function of displacement are derived. The maximum pullout force and corresponding critical displacement are either derived analytically or computed numerically. Key model inputs are a root diameter distribution (uniform, Weibull, or lognormal) and three empirical power law relations describing tensile strength, elastic modulus, and length of roots as functions of root diameter. When a root bundle with root tips anchored in the soil matrix is pulled by a rigid plate, a unique parameter, ?, that depends only on the exponents of the power law relations, dictates the order in which roots of different diameters break. If ? 1, large roots break first. When ? = 1, all fibers break simultaneously, and the maximum tensile force is simply the roots' mean force times the number of roots in the bundle. Based on measurements of root geometry and mechanical properties, the value of ? is less than 1, usually ranging between 0 and 0.7. Thus, small roots always fail first. The model shows how geometrical and mechanical characteristics of roots and root diameter distribution affect the pullout force, its maximum and corresponding displacement. Comparing bundles of roots that have similar mean diameters, a bundle with a narrow variance in root diameter will result in a larger maximum force and a smaller displacement at maximum force than a bundle with a wide diameter distribution. Increasing the mean root diameter of a bundle without changing the distribution's shape increases

  18. Modelling packing interactions in parallel helix bundles: pentameric bundles of nicotinic receptor M2 helices.

    Science.gov (United States)

    Sankararamakrishnan, R; Sansom, M S

    1995-11-01

    The transbilayer pore of the nicotinic acetylcholine receptor (nAChR) is formed by a pentameric bundle of M2 helices. Models of pentameric bundles of M2 helices have been generated using simulated annealing via restrained molecular dynamics. The influence of: (a) the initial C alpha template; and (b) screening of sidechain electrostatic interactions on the geometry of the resultant M2 helix bundles is explored. Parallel M2 helices, in the absence of sidechain electrostatic interactions, pack in accordance with simple ridges-in-grooves considerations. This results in a helix crossing angle of ca. +12 degrees, corresponding to a left-handed coiled coil structure for the bundle as a whole. Tilting of M2 helices away from the central pore axis at their C-termini and/or inclusion of sidechain electrostatic interactions may perturb such ridges-in-grooves packing. In the most extreme cases right-handed coiled coils are formed. An interplay between inter-helix H-bonding and helix bundle geometry is revealed. The effects of changes in electrostatic screening on the dimensions of the pore mouth are described and the significance of these changes in the context of models for the nAChR pore domain is discussed.

  19. A New Class of Macrocyclic Chiral Selectors for Stereochemical Analysis

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-03-11

    This report summarizes the work accomplished in the authors laboratories over the previous three years. During the funding period they have had 23 monographs published or in press, 1 book chapter, 1 patent issued and have delivered 28 invited seminars or plenary lectures on DOE sponsored research. This report covers the work that has been published (or accepted). The most notable aspect of this work involves the successful development and understanding of a new class of fused macrocyclic compounds as pseudophases and selectors in high performance separations (including high performance liquid chromatography, HPLC; capillary electrophoresis, CE; and thin layer chromatography, TLC). They have considerably extended their chiral biomarker work from amber to crude oil and coal. In the process of doing this we've developed several novel separation approaches. They finished their work on the new GSC-PLOT column which is now being used by researchers world-wide for the analysis of gases, light hydrocarbons and halocarbons. Finally, we completed basic studies on immobilizing a cyclodextrin/oligosiloxane hybrid on the wall of fused silica, as well as a basic study on the separation behavior of buckminster fullerene and higher fullerenes.

  20. Short communication: Macrocyclic lactone residues in butter from Brazilian markets.

    Science.gov (United States)

    Macedo, Fabio; Marsico, Eliane Teixeira; Conte-Júnior, Carlos Adam; de Almeida Furtado, Leonardo; Brasil, Taila Figueredo; Pereira Netto, Annibal Duarte

    2015-06-01

    Macrocyclic lactones (ML) are commonly used in drug formulations for the treatment of parasites in cattle. In Brazil, except for drugs (or formulations) with long-term (half-life) effects, ML are registered for use in bovines. Indiscriminate use of ML may result in the presence of residues in milk and dairy products due to their lipophilic properties and thermal stability. This study applied a method of liquid chromatography with fluorimetric detection, recently developed and validated for the determination of residues of abamectin, doramectin, ivermectin, and moxidectin in butter. The method was applied to 38 samples of commercial butter purchased in the metropolitan area of Rio de Janeiro, Brazil, between June and September 2013, analyzed in triplicate. Ivermectin was detected in 89.5% of the samples, with concentrations between 0.3 and 119.4 µg/kg; 76.3% of the samples contained doramectin (0.6 to 64.7 µg/kg) and 55.2% contained abamectin (0.7 to 4.5 µg/kg). Most butter samples (76.3%) contained residues of more than 1 ML; however, no residues of moxidectin were detected. The results showed a high incidence of the presence of avermectins in butter samples. Butter is not included in the Brazilian National Plan for Control of Residues and Contaminants in Animal Products. As ML residues concentrate in lipophilic compounds, butter and other fatty dairy products should be screened for the presence of ML residues.

  1. Dermatobia hominis: Potencial risk of resistance to macrocyclic lactones.

    Science.gov (United States)

    das Neves, José Henrique; Carvalho, Nadino; Amarante, Alessandro F T

    2015-09-15

    Dermatobia hominis is an ectoparasite that infests various species of mammals, including cattle, impairing the quality of cowhides and leather. After observing natural infestation with D. hominis larvae in cattle on two farms in the state of São Paulo, Brazil, we evaluated the efficacy of two macrocyclic lactones, ivermectin and moxidectin, against this parasite. The drugs were administered to 10 animals in each group, following the manufacturer's instructions. The groups were: Group 1-treated with ivermectin (0.2mg/kg of body weight (BW)); Group 2-treated with moxidectin (0.2mg/kg BW); and Group 3-control (untreated). On the farm in Pardinho, a total of 12 and 16 live larvae were found in 6 and in 8 animals 10 days after the treatment with ivermectin and moxidectin, respectively, while in the control group 4 bovines had a total of 7 live larvae. On the farm in Anhembi, 2, 4 and 6 live larvae were extracted from ivermectin, moxidectin and control groups, respectively, after the treatment. This is the first report of the presence of live D. hominis larvae after the treatment of cattle with ivermectin and moxidectin in Brazil. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Supramolecular networking of macrocycles based on exo-coordination: from discrete to continuous frameworks.

    Science.gov (United States)

    Park, Sunhong; Lee, So Young; Park, Ki-Min; Lee, Shim Sung

    2012-03-20

    Macrocyclic ligands typically show high selectivity for specific metal ions and small molecules, and these features make such molecules attractive candidates for nanoscale chemical sensing applications. Crown ethers are macrocyclic structures with polyether linkages where the oxygen donors are often separated by an ethylene unit (-O-CH(2)-CH(2)-O-). Because the oxygen lone pairs in crown-type macrocycles are directed inward, the preorganized macrocyclic cavity tends to form complexes where metals coordinate inside the cavity (endo-coordination). However, sulfur-containing macrocycles often demonstrate metal coordination outside of the cavity (exo-coordination). This coordination behavior results from the different torsion arrangements adopted by the X-CH(2)-CH(2)-X atom sequence (X = O, gauche; X = S, anti) in these molecules. Exo-coordination is synthetically attractive because it would provide a means of connecting macrocyclic building blocks in diverse arrangements. In fact, exo-coordination could allow the construction of more elaborate network assemblies than are possible using conventional endocyclic coordination (which gives metal-in-cavity products). Exo-coordination can also serve as a tool for crystal engineering through the use of diverse controlling factors. Although challenges remain in the development of exo-coordination-based synthetic approaches and, in particular, for the architectural control of supramolecular coordination platforms, we have established several strategies for the rational synthesis of new metallosupramolecules. In this Account, we describe our recent studies of the assembly of metallosupramolecules and coordination polymers based on sulfur-containing macrocycles that employ simple and versatile exo-coordination procedures. Initially, we focus on the unusual topological products such as sandwich (1:2, metal-to-ligand), club sandwich (2:3), and cyclic oligomeric complexes as discrete network systems. The primary structures we

  3. Sequence-defined bioactive macrocycles via an acid-catalysed cascade reaction

    Science.gov (United States)

    Porel, Mintu; Thornlow, Dana N.; Phan, Ngoc N.; Alabi, Christopher A.

    2016-06-01

    Synthetic macrocycles derived from sequence-defined oligomers are a unique structural class whose ring size, sequence and structure can be tuned via precise organization of the primary sequence. Similar to peptides and other peptidomimetics, these well-defined synthetic macromolecules become pharmacologically relevant when bioactive side chains are incorporated into their primary sequence. In this article, we report the synthesis of oligothioetheramide (oligoTEA) macrocycles via a one-pot acid-catalysed cascade reaction. The versatility of the cyclization chemistry and modularity of the assembly process was demonstrated via the synthesis of >20 diverse oligoTEA macrocycles. Structural characterization via NMR spectroscopy revealed the presence of conformational isomers, which enabled the determination of local chain dynamics within the macromolecular structure. Finally, we demonstrate the biological activity of oligoTEA macrocycles designed to mimic facially amphiphilic antimicrobial peptides. The preliminary results indicate that macrocyclic oligoTEAs with just two-to-three cationic charge centres can elicit potent antibacterial activity against Gram-positive and Gram-negative bacteria.

  4. Unsaturated 15 and 16 Membered Appended Naphthalene Macrocyclic Molecules for The Development of Fluorometric Chemosensors

    Science.gov (United States)

    Hasan, S.; Salleh, S.; Hamdan, S.; Yamin, B.

    2017-02-01

    Unsaturated macrocyclic molecules have got an interest due to their potential in catalysis, ion exchange and electron transfer. Salicaldehyde derivatives macrocyclic molecules have a broad range in synthesis. In this study, two unsaturated macrocyclic molecules (L1 and L2) have been synthesized. The preparation of unsaturated macrocyclic ligands involve two steps; the reaction of salicylaldehyde with 1,2-dibromoethane or 1,4-dibromobutane to produce precursor, then cyclisation were completed using schiff base technique by adding diamines (naphthalene diamine). The ligands were characterized spectroscopically. In FT-IR spectrums, the form of the ligands mainly can be observed on the disappearance of the carbonyl group of aldehyde at approximately 1650cm-1 that was readily assigned to C=O group of salicylaldehyde with the replacement of C=N peak at 1684.13cm-1. The success in producing macrocyclic ligands have been further characterized using fluorescence emission spectroscopy (FES) and revealed the typical emission of naphthalene at ∼430nm. Fluorescence changes of L1 and L2 showed high selectivity for Fe3+ and Cu2+ respectively in the presence of other common metal ions, such as Zn2+, Ni2+ and Co2+. Besides, the ligand was sensitive enough to detect the concentration of ferric ion with the detection limit down to 1.08 x 10-6 M and fluorescence change that was unaffected by the presence of other common coexisting metal ions. Complexation with Co(II) was also attempted.

  5. An Alternative Bundle-to-Bundle Suturing Technique for Repairing Fresh Achilles Tendon Rupture.

    Science.gov (United States)

    Zhao, Jingjing; Yu, Bin; Xie, Ming; Huang, Ruokun; Xiao, Kai

    2016-01-01

    The main concern about conventional Achilles tendon repair surgical techniques is how to maintain the initial strength of the ruptured Achilles tendon through complicated suturing methods. The primary surgical problem lies in the properties of the soft tissue; the deterioration of the Achilles tendon, especially in its elasticity; and the surface lubricity of the local tissues. In the present study, we describe an innovative bundle-to-bundle suturing method that addresses these potential problems. Copyright © 2016 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

  6. Synthesis of azomethine macrocycles by condensation of dicarbonyl compounds with diamines without using metal ions as template agents

    Energy Technology Data Exchange (ETDEWEB)

    Borisova, Natalia E; Reshetova, Marina D; Ustynyuk, Yuri A [Department of Chemistry, M.V. Lomonosov Moscow State University, Moscow (Russian Federation)

    2007-09-30

    Different strategies for the synthesis of symmetrical and unsymmetrical macrocyclic Schiff bases in the absence of metal ions are considered. General methods for performing macrocyclisation under thermodynamic or kinetic control are analysed. The key factors influencing the structure of macrocyclic azomethines are discussed.

  7. Nitrogen-Phosphorus(III)-Chalcogen Macrocycles for the Synthesis of Polynuclear Silver(I) Sandwich Complexes.

    Science.gov (United States)

    Yogendra, Sivathmeehan; Hennersdorf, Felix; Weigand, Jan J

    2017-08-07

    The synthesis of inorganic N-P(III)-Ch-based macrocycles [-PhP-NMe-PPh-Ch-]2 (8Ch; Ch = S, Se) is presented by incorporating two nitrogen, two chalcogen, and four phosphorus atoms. The macrocycles are conveniently obtained via the cyclocondensation reaction of Na2Ch (Ch = S, Se) with the acyclic dichlorodiphosphazane ClPhP-NMe-PClPh (9). Treatment with elemental sulfur (S8) or gray selenium (Segray) results in an oxidative ring contraction to give 1,3,2,4-thiazadiphosphetidine 2,4-disulfide (10S) and 1,3,2,4-selenazadiphosphetidine 2,4-diselenide (10Se), respectively. Macrocycles 8Ch are excellent multidentate ligands for transition metal complexation, as demonstrated by the isolation of mono-, di- tri-, and tetranuclear silver sandwich complexes. The polynuclear silver complexes are comprehensively characterized, including detailed NMR and X-ray analysis.

  8. Self-assembled monolayers of shape-persistent macrocycles on graphite: interior design and conformational polymorphism.

    Science.gov (United States)

    Vollmeyer, Joscha; Eberhagen, Friederike; Höger, Sigurd; Jester, Stefan-S

    2014-01-01

    Three shape-persistent naphthylene-phenylene-acetylene macrocycles of identical backbone structures and extraannular substitution patterns but different (empty, apolar, polar) nanopore fillings are self-assembled at the solid/liquid interface of highly oriented pyrolytic graphite and 1,2,4-trichlorobenzene. Submolecularly resolved images of the resulting two-dimensional (2D) crystalline monolayer patterns are obtained by in situ scanning tunneling microscopy. A concentration-dependent conformational polymorphism is found, and open and more dense packing motifs are observed. For all three compounds alike lattice parameters are found, therefore the intermolecular macrocycle distances are mainly determined by their size and symmetry. This is an excellent example that the graphite acts as a template for the macrocycle organization independent from their specific interior.

  9. Theoretical prediction of some novel nanotubes composed of macrocyclic structures: A DFT study

    Science.gov (United States)

    Masoodi, Hamid Reza; Bagheri, Sotoodeh; Ranjbar-Karimi, Reza

    2017-01-01

    Our interests in this paper are the elucidation of structural and electronic properties of some π-conjugated macrocycles composed of borazine and alumazene rings as well as the investigation of their potential utility for the creation of new nanotubes. Here, the calculations are performed at B3LYP/6-31+G(d) and M06-2X/6-31+G(d)//B3LYP/6-31+G(d) levels of theory. The results suggest that the self-assembly of the macrocyclic compounds can be considered to form new nanotubes through π-π stacking. Also, meaningful correlations are found between the stability and photoconductivity applications of the nanotubes and the number of stacked π-conjugated macrocycles.

  10. Self-assembled monolayers of shape-persistent macrocycles on graphite: interior design and conformational polymorphism

    Directory of Open Access Journals (Sweden)

    Joscha Vollmeyer

    2014-11-01

    Full Text Available Three shape-persistent naphthylene–phenylene–acetylene macrocycles of identical backbone structures and extraannular substitution patterns but different (empty, apolar, polar nanopore fillings are self-assembled at the solid/liquid interface of highly oriented pyrolytic graphite and 1,2,4-trichlorobenzene. Submolecularly resolved images of the resulting two-dimensional (2D crystalline monolayer patterns are obtained by in situ scanning tunneling microscopy. A concentration-dependent conformational polymorphism is found, and open and more dense packing motifs are observed. For all three compounds alike lattice parameters are found, therefore the intermolecular macrocycle distances are mainly determined by their size and symmetry. This is an excellent example that the graphite acts as a template for the macrocycle organization independent from their specific interior.

  11. Amplitude death of coupled hair bundles with stochastic channel noise

    CERN Document Server

    Kim, Kyung-Joong

    2014-01-01

    Hair cells conduct auditory transduction in vertebrates. In lower vertebrates such as frogs and turtles, due to the active mechanism in hair cells, hair bundles(stereocilia) can be spontaneously oscillating or quiescent. Recently, the amplitude death phenomenon has been proposed [K.-H. Ahn, J. R. Soc. Interface, {\\bf 10}, 20130525 (2013)] as a mechanism for auditory transduction in frog hair-cell bundles, where sudden cessation of the oscillations arises due to the coupling between non-identical hair bundles. The gating of the ion channel is intrinsically stochastic due to the stochastic nature of the configuration change of the channel. The strength of the noise due to the channel gating can be comparable to the thermal Brownian noise of hair bundles. Thus, we perform stochastic simulations of the elastically coupled hair bundles. In spite of stray noisy fluctuations due to its stochastic dynamics, our simulation shows the transition from collective oscillation to amplitude death as inter-bundle coupling str...

  12. Monopoles and Modifications of Bundles over Elliptic Curves

    Directory of Open Access Journals (Sweden)

    Andrey M. Levin

    2009-06-01

    Full Text Available Modifications of bundles over complex curves is an operation that allows one to construct a new bundle from a given one. Modifications can change a topological type of bundle. We describe the topological type in terms of the characteristic classes of the bundle. Being applied to the Higgs bundles modifications establish an equivalence between different classical integrable systems. Following Kapustin and Witten we define the modifications in terms of monopole solutions of the Bogomolny equation. We find the Dirac monopole solution in the case R × (elliptic curve. This solution is a three-dimensional generalization of the Kronecker series. We give two representations for this solution and derive a functional equation for it generalizing the Kronecker results. We use it to define Abelian modifications for bundles of arbitrary rank. We also describe non-Abelian modifications in terms of theta-functions with characteristic.

  13. A Tannakian approach to dimensional reduction of principal bundles

    CERN Document Server

    Álvarez-Cónsul, Luis; García-Prada, Oscar

    2016-01-01

    Let $P$ be a parabolic subgroup of a connected simply connected complex semisimple Lie group $G$. Given a compact K\\"ahler manifold $X$, the dimensional reduction of $G$-equivariant holomorphic vector bundles over $X\\times G/P$ was carried out by the first and third authors. This raises the question of dimensional reduction of holomorphic principal bundles over $X\\times G/P$. The method used for equivariant vector bundles does not generalize to principal bundles. In this paper, we adapt to equivariant principal bundles the Tannakian approach of Nori, to describe the dimensional reduction of $G$-equivariant principal bundles over $X\\times G/P$, and to establish a Hitchin--Kobayashi type correspondence. In order to be able to apply the Tannakian theory, we need to assume that $X$ is a complex projective manifold.

  14. The avalanche process of the fiber bundle model with defect

    Science.gov (United States)

    Hao, Da-Peng; Tang, Gang; Xia, Hui; Xun, Zhi-Peng; Han, Kui

    2017-04-01

    In order to explore the impacts of defect on the tensile fracture process of materials, the fiber bundle model with defect is constructed based on the classical fiber bundle model. In the fiber bundle model with defect, the two key parameters are the mean size and the density of defects. In both uniform and Weibull threshold distributions, the mean size and density all bring impacts on the threshold distribution of fibers. By means of analytical approximation and numerical simulation, we show that the two key parameters of the model have substantial effects on the failure process of the bundle. From macroscopic view, the defect described by the altering of threshold distribution of fibers will has a significant impact on the mechanical properties of the bundle. While in microscopic scale, the statistical properties of the model are still harmonious with the classical fiber bundle model.

  15. Cosmic multimuon bundles detected by DELPHI

    CERN Document Server

    Rídky, J

    2004-01-01

    The DELPHI detector located at LEP accelerator has been used also to measure multimuon bundles originated from cosmic ray interactions. Two subdetectors-hadron calorimeter and time projection chamber, are used for this purpose. The 1999 and 2000 data are analyzed over wide range of multiplicities. The multiplicity distribution is compared with prediction of Monte Carlo simulation based on CORSIKA/QGSJET. The Monte-Carlo does not describe the large multiplicity part of data. Even the extreme assumption on the cosmic ray composition (pure iron nuclei) hardly predicts comparable number of high-multiplicity events.

  16. Differential geometry of complex vector bundles

    CERN Document Server

    Kobayashi, Shoshichi

    2014-01-01

    Holomorphic vector bundles have become objects of interest not only to algebraic and differential geometers and complex analysts but also to low dimensional topologists and mathematical physicists working on gauge theory. This book, which grew out of the author's lectures and seminars in Berkeley and Japan, is written for researchers and graduate students in these various fields of mathematics. Originally published in 1987. The Princeton Legacy Library uses the latest print-on-demand technology to again make available previously out-of-print books from the distinguished backlist of Princeto

  17. Higher order mechanics on graded bundles

    Science.gov (United States)

    Bruce, Andrew James; Grabowska, Katarzyna; Grabowski, Janusz

    2015-05-01

    In this paper we develop a geometric approach to higher order mechanics on graded bundles in both, the Lagrangian and Hamiltonian formalism, via the recently discovered weighted algebroids. We present the corresponding Tulczyjew triple for this higher order situation and derive in this framework the phase equations from an arbitrary (also singular) Lagrangian or Hamiltonian, as well as the Euler-Lagrange equations. As important examples, we geometrically derive the classical higher order Euler-Lagrange equations and analogous reduced equations for invariant higher order Lagrangians on Lie groupoids.

  18. Bundling Products and Services Through Modularization Strategies

    DEFF Research Database (Denmark)

    Bask, Anu; Hsuan, Juliana; Rajahonka, Mervi;

    2012-01-01

    Modularity has been recognized as a powerful tool in improving the efficiency and management of product design and manufacturing. However, the integrated view on covering both, product and service modularity for product-service systems (PSS), is under researched. Therefore, in this paper our...... objective is to contribute to the PSS modularity. Thus, we describe configurations of PSSs and the bundling of products and services through modularization strategies. So far there have not been tools to analyze and determine the correct combinations of degrees of product and service modularities....

  19. Compression of a bundle of light rays.

    Science.gov (United States)

    Marcuse, D

    1971-03-01

    The performance of ray compression devices is discussed on the basis of a phase space treatment using Liouville's theorem. It is concluded that the area in phase space of the input bundle of rays is determined solely by the required compression ratio and possible limitations on the maximum ray angle at the output of the device. The efficiency of tapers and lenses as ray compressors is approximately equal. For linear tapers and lenses the input angle of the useful rays must not exceed the compression ratio. The performance of linear tapers and lenses is compared to a particular ray compressor using a graded refractive index distribution.

  20. Vector bundles on complex projective spaces

    CERN Document Server

    Okonek, Christian; Spindler, Heinz

    1980-01-01

    This expository treatment is based on a survey given by one of the authors at the Séminaire Bourbaki in November 1978 and on a subsequent course held at the University of Göttingen. It is intended to serve as an introduction to the topical question of classification of holomorphic vector bundles on complex projective spaces, and can easily be read by students with a basic knowledge of analytic or algebraic geometry. Short supplementary sections describe more advanced topics, further results, and unsolved problems.

  1. Macrocyclic ligands for uranium complexation. Final report, August 1, 1986--March 31, 1993

    Energy Technology Data Exchange (ETDEWEB)

    Potts, K.T.

    1993-12-31

    Macrocycles, designed for complexation of the uranyl ion by computer modeling studies and utilizing six ligating atoms in the equatorial plane of the uranyl ions, have been prepared and their complexation of the uranyl ions evaluated. The ligating atoms, either oxygen or sulfur, were part of acylurea, biuret or thiobiuret subunits with alkane chains or pyridine units completing the macrocyclic periphery. These macrocycles with only partial preorganization formed uranyl complexes in solution but no crystalline complexes were isolated. Refinement of the cavity diameter by variation of the peripheral functional groups is currently studied to achieve an optimized cavity diameter of 4.7--5.2 {angstrom}. Acyclic ligands containing the same ligating atoms in equivalent functional entities were found to form a crystalline 1:1 uranyl-ligand complex (stability constant log K = 10.7) whose structure was established by X-ray data. This complex underwent a facile, DMSO-induced rearrangement to a 2:1 uranyl-ligand complex whose structure was also established by X-ray data. The intermediates to the macrocycles all behaved as excellent ligands for the complexation of transition metals. Acylthiourea complexes of copper and nickel as well as intermolecular, binuclear copper and nickel complexes of bidentate carbonyl thioureas formed readily and their structures were established in several representative instances by X-ray structural determinations. Tetradentate bis(carbonylthioureas) were found to be very efficient selective reagents for the complexation of copper in the presence of nickel ions. Several preorganized macrocycles were also prepared but in most instances these macrocycles underwent ring-opening under complexation conditions.

  2. Crossed and Linked Histories of Tetrapyrrolic Macrocycles and Their Use for Engineering Pores within Sol-Gel Matrices

    Directory of Open Access Journals (Sweden)

    Miguel A. García-Sánchez

    2013-01-01

    Full Text Available The crossed and linked histories of tetrapyrrolic macrocycles, interwoven with new research discoveries, suggest that Nature has found in these structures a way to ensure the continuity of life. For diverse applications porphyrins or phthalocyanines must be trapped inside solid networks, but due to their nature, these compounds cannot be introduced by thermal diffusion; the sol-gel method makes possible this insertion through a soft chemical process. The methodologies for trapping or bonding macrocycles inside pristine or organo-modified silica or inside ZrO2 xerogels were developed by using phthalocyanines and porphyrins as molecular probes. The sizes of the pores formed depend on the structure, the cation nature, and the identities and positions of peripheral substituents of the macrocycle. The interactions of the macrocyclic molecule and surface Si-OH groups inhibit the efficient displaying of the macrocycle properties and to avoid this undesirable event, strategies such as situating the macrocycle far from the pore walls or to exchange the Si-OH species by alkyl or aryl groups have been proposed. Spectroscopic properties are better preserved when long unions are established between the macrocycle and the pore walls, or when oligomeric macrocyclic species are trapped inside each pore. When macrocycles are trapped inside organo-modified silica, their properties result similar to those displayed in solution and their intensities depend on the length of the alkyl chain attached to the matrix. These results support the prospect of tuning up the pore size, surface area, and polarity inside the pore cavities in order to prepare efficient catalytic, optical, sensoring, and medical systems. The most important feature is that research would confirm again that tetrapyrrolic macrocycles can help in the development of the authentic pore engineering in materials science.

  3. Heat transfer in bundles of finned tubes in crossflow

    Energy Technology Data Exchange (ETDEWEB)

    Stasiulevicius, J.; Skrinska, A.; Zukauskas, A.; Hewitt, G.F.

    1986-01-01

    This book provides correlations of heat transfer and hydraulic data for bundles of finned tubes in crossflow at high Reynolds numbers. Results of studies of the effectiveness of the fin, local, and mean heat transfer coefficients are presented. The effect of geometric parameters of the fins and of the location of tubes in the bundle on heat transfer and hydraulic drag are described. The resistance of the finned tube bundles under study and other factors are examined.

  4. Coolability of ballooned VVER bundles with pellet relocation

    Energy Technology Data Exchange (ETDEWEB)

    Hozer, Z.; Nagy, I.; Windberg, P.; Vimi, A. [AEKI, P.O.box 49, Budapest, H-1525 (Hungary)

    2009-06-15

    During a LOCA incident the high pressure in the fuel rods can lead to clad ballooning and the debris of fuel pellets can fill the enlarged volume. The evaluation of the role of these two effects on the coolability of VVER type fuel bundles was the main objective of the experimental series. The tests were carried out in the modified configuration of the CODEX facility. 19-rod electrically heated VVER type bundle was used. The test section was heated up to 600 deg. C in steam atmosphere and the bundle was quenched from the bottom by cold water. Three series of tests were performed: 1. Reference bundle with fuel rods without ballooning, with uniform power profile. 2. Bundle with 86% blockage rate and with uniform power profile. The blockage rate was reached by superimposing hollow sleeves on all 19 fuel rods. 3. Bundle with 86% blockage rate and with local power peak in the ballooned area. The local power peak was produced by the local reduction the cross section of the internal heater bar inside of the fuel rods. In all three bundle configurations three different cooling water flow-rates were applied. The experimental results confirmed that a VVER bundle with even 86% blockage rate remains coolable after a LOCA event. The ballooned section creates some obstacles for the cooling water during reflood of the bundle, but this effect causes only a short delay in the cooling down of the hot fuel rods. Earlier tests on the coolability of ballooned bundles were performed only with Western type bundles with square fuel lattice. The present test series was the first confirmation of the coolability of VVER type bundles with triangular lattice. The accumulation of fuel pellet debris in the ballooned volume results in a local power peak, which leads to further slowing down of quench front. The first tests indicated that the effect of local power peak was less significant on the delay of cooling down than the effect of ballooning. (authors)

  5. Heat Transfer Analysis in Wire Bundles for Aerospace Vehicles

    Science.gov (United States)

    Rickman, S. L.; Iamello, C. J.

    2016-01-01

    Design of wiring for aerospace vehicles relies on an understanding of "ampacity" which refers to the current carrying capacity of wires, either, individually or in wire bundles. Designers rely on standards to derate allowable current flow to prevent exceedance of wire temperature limits due to resistive heat dissipation within the wires or wire bundles. These standards often add considerable margin and are based on empirical data. Commercial providers are taking an aggressive approach to wire sizing which challenges the conventional wisdom of the established standards. Thermal modelling of wire bundles may offer significant mass reduction in a system if the technique can be generalized to produce reliable temperature predictions for arbitrary bundle configurations. Thermal analysis has been applied to the problem of wire bundles wherein any or all of the wires within the bundle may carry current. Wire bundles present analytical challenges because the heat transfer path from conductors internal to the bundle is tortuous, relying on internal radiation and thermal interface conductance to move the heat from within the bundle to the external jacket where it can be carried away by convective and radiative heat transfer. The problem is further complicated by the dependence of wire electrical resistivity on temperature. Reduced heat transfer out of the bundle leads to higher conductor temperatures and, hence, increased resistive heat dissipation. Development of a generalized wire bundle thermal model is presented and compared with test data. The steady state heat balance for a single wire is derived and extended to the bundle configuration. The generalized model includes the effects of temperature varying resistance, internal radiation and thermal interface conductance, external radiation and temperature varying convective relief from the free surface. The sensitivity of the response to uncertainties in key model parameters is explored using Monte Carlo analysis.

  6. The Porphobilinogen Conundrum in Prebiotic Routes to Tetrapyrrole Macrocycles

    Science.gov (United States)

    Taniguchi, Masahiko; Ptaszek, Marcin; Chandrashaker, Vanampally; Lindsey, Jonathan S.

    2017-03-01

    Attempts to develop a credible prebiotic route to tetrapyrroles have relied on enzyme-free recapitulation of the extant biosynthesis, but this process has foundered from the inability to form the pyrrole porphobilinogen ( PBG) in good yield by self-condensation of the precursor δ-aminolevulinic acid ( ALA). PBG undergoes robust oligomerization in aqueous solution to give uroporphyrinogen (4 isomers) in good yield. ALA, PBG, and uroporphyrinogen III are universal precursors to all known tetrapyrrole macrocycles. The enzymic formation of PBG entails carbon-carbon bond formation between the less stable enolate/enamine of one ALA molecule (3-position) and the carbonyl/imine (4-position) of the second ALA molecule; without enzymes, the first ALA reacts at the more stable enolate/enamine (5-position) and gives the pyrrole pseudo-PBG. pseudo-PBG cannot self-condense, yet has one open α-pyrrole position and is proposed to be a terminator of oligopyrromethane chain-growth from PBG. Here, 23 analogues of ALA have been subjected to density functional theoretical (DFT) calculations, but no motif has been identified that directs reaction at the 3-position. Deuteriation experiments suggested 5-(phosphonooxy)levulinic acid would react preferentially at the 3- versus 5-position, but a hybrid condensation with ALA gave no observable uroporphyrin. The results suggest efforts toward a biomimetic, enzyme-free route to tetrapyrroles from ALA should turn away from structure-directed reactions and focus on catalysts that orient the two aminoketones to form PBG in a kinetically controlled process, thereby avoiding formation of pseudo-PBG.

  7. BINOL Macrocycle Derivatives: Synthesis of New Dinaphthyl Sulfide Aza Oxa Thia Crowns (Lariats

    Directory of Open Access Journals (Sweden)

    Abbas Shockravi

    2013-01-01

    Full Text Available In this research work, dinaphthyl sulfide diester was prepared from the reaction of 1,1′-thiobis (2-hydroxy naphthalene and methylchloroacetate. Its aza-macrocyclic derivative was synthesized from the reaction of dinaphthyl sulfide diester and diethylenetriamine. Lariats were prepared from the reaction of chloroamides (four derivatives and initial macrocycle. Chloroamides were synthesized from the reaction of amines (aniline, benzylamine, 8-amino quinoline and 4-amino azobenzene and chloroacetyl chloride. All the materials were identified by IR, 1H NMR, 13C NMR, and mass spectroscopies, and elemental analysis.

  8. Synthesis and electrochemical studies of phenylazo substituted tetraaza macrocyclic complexes of Ni(II)

    Indian Academy of Sciences (India)

    Randhir Singh; Suresh Kumar; Amarendra Bhattacharya

    2000-12-01

    Synthesis and characterization of some phenyl azo substituted tetraaza macrocyclic complexes of Ni(II) are reported. Electrochemical behaviour of these macrocyclic complexes has been examined using polarographic, voltammetric and spectroscopic techniques. These studies show that both the ligand and the metal are electrochemically active. The electrochemical behaviour of the azo function has been shown to occur through a single four-electron process. When a nitro group is also present, the nitro function of the azo moiety is reduced in a six-electron cathodic wave.

  9. Synthesis and extended activity of triazole-containing macrocyclic protease inhibitors

    DEFF Research Database (Denmark)

    Pehere, A.D.; Pietsch, M.; Gütschow, M.;

    2013-01-01

    Peptide-derived protease inhibitors are an important class of compounds with the potential to treat a wide range of diseases. Herein, we describe the synthesis of a series of triazole- containing macrocyclic protease inhibitors pre-organized into a b-strand conformation and an evaluation...... of their activity against a panel of proteases. Acyclic azidoalkyne-based aldehydes are also evaluated for comparison. The macrocyclic peptidomimetics showed considerable activity towards calpain II, cathepsin L and S, and the 20S proteasome chymotrypsin-like activity. Some of the first examples of highly potent...

  10. Macrocyclic prolinyl acyl guanidines as inhibitors of β-secretase (BACE).

    Science.gov (United States)

    Boy, Kenneth M; Guernon, Jason M; Wu, Yong-Jin; Zhang, Yunhui; Shi, Joe; Zhai, Weixu; Zhu, Shirong; Gerritz, Samuel W; Toyn, Jeremy H; Meredith, Jere E; Barten, Donna M; Burton, Catherine R; Albright, Charles F; Good, Andrew C; Grace, James E; Lentz, Kimberley A; Olson, Richard E; Macor, John E; Thompson, Lorin A

    2015-11-15

    The synthesis, evaluation, and structure-activity relationships of a class of acyl guanidines which inhibit the BACE-1 enzyme are presented. The prolinyl acyl guanidine chemotype (7c), unlike compounds of the parent isothiazole chemotype (1), yielded compounds with good agreement between their enzymatic and cellular potency as well as a reduced susceptibility to P-gp efflux. Further improvements in potency and P-gp ratio were realized via a macrocyclization strategy. The in vivo profile in wild-type mice and P-gp effects for the macrocyclic analog 21c is presented.

  11. [2+2+2] Cycloaddition Reactions of Macrocyclic Systems Catalyzed by Transition Metals. A Review

    Directory of Open Access Journals (Sweden)

    Anna Roglans

    2010-12-01

    Full Text Available Polyalkyne and enediyne azamacrocycles are prepared from arenesulfonamides and various alkyne and alkene derivatives either under basic or neutral conditions. The new family of macrocyclic substrates is tested in the [2+2+2] cycloaddition reaction. Several catalysts are used for the cycloisomerization reaction, and their enantioinduction is evaluated as appropriate. The effect of the structural features of the macrocycles, namely the ring size, substituents in precise positions and the number and type of unsaturations, on the [2+2+2] cycloaddition reaction has also been studied.

  12. Isothermal microcalorimetry, a tool for probing SWNT bundles.

    Science.gov (United States)

    Marquis, Renaud; Greco, Carla; Schultz, Patrick; Meunier, Stéphane; Mioskowski, Charles

    2009-11-01

    The bundling state of several dry single-walled carbon nanotube (SWNT) samples is compared using isothermal microcalorimetry (IMC). So as to get different dry samples with various bundling states, the pristine SWNTs were pretreated with a solution of an aromatic amphiphile with or without sonication, washed and dried before being studied by IMC. The bundling state of the different SWNT samples, which was first analyzed by TEM, was then correlated to the obtained IMC data thanks to the interpretation of the observed energy transfer phenomena. From our results, IMC appears to be an interesting technique for the surface probing of dry SWNT samples, and herein for the evaluation of the bundling state.

  13. Restriction Theorem for Principal bundles in Arbitrary Characteristic

    DEFF Research Database (Denmark)

    Gurjar, Sudarshan

    2015-01-01

    The aim of this paper is to prove two basic restriction theorem for principal bundles on smooth projective varieties in arbitrary characteristic generalizing the analogues theorems of Mehta-Ramanathan for vector bundles. More precisely, let G be a reductive algebraic group over an algebraically...... closed field k and let X be a smooth, projective variety over k together with a very ample line bundle O(1). The main result of the paper is that if E is a semistable (resp. stable) principal G-bundle on X w.r.t O(1), then the restriction of E to a general, high multi-degree, complete-intersection curve...

  14. Enthalpy and void distributions in subchannels of PHWR fuel bundles

    Energy Technology Data Exchange (ETDEWEB)

    Park, J. W.; Choi, H.; Rhee, B. W. [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1998-12-31

    Two different types of the CANDU fuel bundles have been modeled for the ASSERT-IV code subchannel analysis. From calculated values of mixture enthalpy and void fraction distribution in the fuel bundles, it is found that net buoyancy effect is pronounced in the central region of the DUPIC fuel bundle when compared with the standard CANDU fuel bundle. It is also found that the central region of the DUPIC fuel bundle can be cooled more efficiently than that of the standard fuel bundle. From the calculated mixture enthalpy distribution at the exit of the fuel channel, it is found that the mixture enthalpy and void fraction can be highest in the peripheral region of the DUPIC fuel bundle. On the other hand, the enthalpy and the void fraction were found to be highest in the central region of the standard CANDU fuel bundle at the exit of the fuel channel. This study shows that the subchannel analysis is very useful in assessing thermal behavior of the fuel bundle that could be used in CANDU reactors. 10 refs., 4 figs., 2 tabs. (Author)

  15. Bundled capillary electrophoresis using microstructured fibres.

    Science.gov (United States)

    Rogers, Benjamin; Gibson, Graham T T; Oleschuk, Richard D

    2011-01-01

    Joule heating, arising from the electric current passing through the capillary, causes many undesired effects in CE that ultimately result in band broadening. The use of narrow-bore capillaries helps to solve this problem as smaller cross-sectional area results in decreased Joule heating and the rate of heat dissipation is increased by the larger surface-to-volume ratio. Issues arising from such small capillaries, such as poor detection sensitivity, low loading capacity and high flow-induced backpressure (complicating capillary loading) can be avoided by using a bundle of small capillaries operating simultaneously that share buffer reservoirs. Microstructured fibres, originally designed as waveguides in the telecommunication industry, are essentially a bundle of parallel ∼5 μm id channels that extend the length of a fibre having otherwise similar dimensions to conventional CE capillaries. This work presents the use of microstructured fibres for CZE, taking advantage of their relatively high surface-to-volume ratio and the small individual size of each channel to effect highly efficient separations, particularly for dye-labelled peptides.

  16. Development boiling to sprinkled tube bundle

    Directory of Open Access Journals (Sweden)

    Kracík Petr

    2016-01-01

    Full Text Available This paper presents results of a studied heat transfer coefficient at the surface of a sprinkled tube bundle where boiling occurs. Research in the area of sprinkled exchangers can be divided into two major parts. The first part is research on heat transfer and determination of the heat transfer coefficient at sprinkled tube bundles for various liquids, whether boiling or not. The second part is testing of sprinkle modes for various tube diameters, tube pitches and tube materials and determination of individual modes’ interface. All results published so far for water as the falling film liquid apply to one to three tubes for which the mentioned relations studied are determined in rigid laboratory conditions defined strictly in advance. The sprinkled tubes were not viewed from the operational perspective where there are more tubes and various modes may occur in different parts with various heat transfer values. The article focuses on these processes. The tube is located in a low-pressure chamber where vacuum is generated using an exhauster via ejector. The tube consists of smooth copper tubes of 12 mm diameter placed horizontally one above another.

  17. Development boiling to sprinkled tube bundle

    Science.gov (United States)

    Kracík, Petr; Pospíšil, Jiří

    2016-03-01

    This paper presents results of a studied heat transfer coefficient at the surface of a sprinkled tube bundle where boiling occurs. Research in the area of sprinkled exchangers can be divided into two major parts. The first part is research on heat transfer and determination of the heat transfer coefficient at sprinkled tube bundles for various liquids, whether boiling or not. The second part is testing of sprinkle modes for various tube diameters, tube pitches and tube materials and determination of individual modes' interface. All results published so far for water as the falling film liquid apply to one to three tubes for which the mentioned relations studied are determined in rigid laboratory conditions defined strictly in advance. The sprinkled tubes were not viewed from the operational perspective where there are more tubes and various modes may occur in different parts with various heat transfer values. The article focuses on these processes. The tube is located in a low-pressure chamber where vacuum is generated using an exhauster via ejector. The tube consists of smooth copper tubes of 12 mm diameter placed horizontally one above another.

  18. Molybdenum-99-producing 37-element fuel bundle neutronically and thermal-hydraulically equivalent to a standard CANDU fuel bundle

    Energy Technology Data Exchange (ETDEWEB)

    Nichita, E., E-mail: Eleodor.Nichita@uoit.ca; Haroon, J., E-mail: Jawad.Haroon@uoit.ca

    2016-10-15

    Highlights: • A 37-element fuel bundle modified for {sup 99}Mo production in CANDU reactors is presented. • The modified bundle is neutronically and thermal-hydraulically equivalent to the standard bundle. • The modified bundle satisfies all safety criteria satisfied by the standard bundle. - Abstract: {sup 99m}Tc, the most commonly used radioisotope in diagnostic nuclear medicine, results from the radioactive decay of {sup 99}Mo which is currently being produced at various research reactors around the globe. In this study, the potential use of CANDU power reactors for the production of {sup 99}Mo is investigated. A modified 37-element fuel bundle, suitable for the production of {sup 99}Mo in existing CANDU-type reactors is proposed. The new bundle is specifically designed to be neutronically and thermal-hydraulically equivalent to the standard 37-element CANDU fuel bundle in normal, steady-state operation and, at the same time, be able to produce significant quantities of {sup 99}Mo when irradiated in a CANDU reactor. The proposed bundle design uses fuel pins consisting of a depleted-uranium centre surrounded by a thin layer of low-enriched uranium. The new molybdenum-producing bundle is analyzed using the lattice transport code DRAGON and the diffusion code DONJON. The proposed design is shown to produce 4081 six-day Curies of {sup 99}Mo activity per bundle when irradiated in the peak-power channel of a CANDU core, while maintaining the necessary reactivity and power rating limits. The calculated {sup 99}Mo yield corresponds to approximately one third of the world weekly demand. A production rate of ∼3 bundles per week can meet the global demand of {sup 99}Mo.

  19. Evaluation of Single-Bundle versus Double-Bundle PCL Reconstructions with More Than 10-Year Follow-Up

    Directory of Open Access Journals (Sweden)

    Masataka Deie

    2015-01-01

    Full Text Available Background. Posterior cruciate ligament (PCL injuries are not rare in acute knee injuries, and several recent anatomical studies of the PCL and reconstructive surgical techniques have generated improved patient results. Now, we have evaluated PCL reconstructions performed by either the single-bundle or double-bundle technique in a patient group followed up retrospectively for more than 10 years. Methods. PCL reconstructions were conducted using the single-bundle (27 cases or double-bundle (13 cases method from 1999 to 2002. The mean age at surgery was 34 years in the single-bundle group and 32 years in the double-bundle group. The mean follow-up period was 12.5 years. Patients were evaluated by Lysholm scoring, the gravity sag view, and knee arthrometry. Results. The Lysholm score after surgery was 89.1±5.6 points for the single-bundle group and 91.9±4.5 points for the double-bundle group. There was no significant difference between the methods in the side-to-side differences by gravity sag view or knee arthrometer evaluation, although several cases in both groups showed a side-to-side difference exceeding 5 mm by the latter evaluation method. Conclusions. We found no significant difference between single- and double-bundle PCL reconstructions during more than 10 years of follow-up.

  20. Safety assessment for the CANFLEX-NU fuel bundles with respect to the 37-element fuel bundles

    Energy Technology Data Exchange (ETDEWEB)

    Suk, H. C.; Lim, H. S. [Korea Atomic Energy Research Institute, Taejon (Korea)

    1999-11-01

    The KAERI and AECL have jointly developed an advanced CANDU fuel, called CANFLEX-NU fuel bundle. CANFLEX 43-element bundle has some improved features of increased operating margin and enhanced safety compared to the existing 37-element bundle. Since CANFLEX fuel bundle is designed to be compatible with the CANDU-6 reactor design, the behaviour in the thermalhydraulic system will be nearly identical with 37-element bundle. But due to different element design and linear element power distribution between the two bundles, it is expected that CANFLEX fuel behaviour would be different from the behaviour of the 37-element fuel. Therefore, safety assessments on the design basis accidents which result if fuel failures are performed. For all accidents selected, it is observed that the loading of CANFLEX bundle in an existing CANDU-6 reactor would not worsen the reactor safety. It is also predicted that fission product release for CANFLEX fuel bundle generally is lower than that for 37-element bundle. 3 refs., 2 figs., 2 tabs. (Author)

  1. Coherent hollow-core waveguide bundles for thermal imaging.

    Science.gov (United States)

    Gal, Udi; Harrington, James; Ben-David, Moshe; Bledt, Carlos; Syzonenko, Nicholas; Gannot, Israel

    2010-09-01

    There has been very little work done in the past to extend the wavelength range of fiber image bundles to the IR range. This is due, in part, to the lack of IR transmissive fibers with optical and mechanical properties analogous to the oxide glass fibers currently employed in the visible fiber bundles. Our research is aimed at developing high-resolution hollow-core coherent IR fiber bundles for transendoscopic infrared imaging. We employ the hollow glass waveguide (HGW) technology that was used successfully to make single-HGWs with Ag/AgI thin film coatings to form coherent bundles for IR imaging. We examine the possibility of developing endoscopic systems to capture thermal images using hollow waveguide fiber bundles adjusted to the 8-10?mum spectral range and investigate the applicability of such systems. We carried out a series of measurements in order to characterize the optical properties of the fiber bundles. These included the attenuation, resolution, and temperature response. We developed theoretical models and simulation tools that calculate the light propagation through HGW bundles, and which can be used to calculate the optical properties of the fiber bundles. Finally, the HGW fiber bundles were used to transmit thermal images of various heated objects; the results were compared with simulation results. The experimental results are encouraging, show an improvement in the resolution and thermal response of the HGW fiber bundles, and are consistent with the theoretical results. Nonetheless, additional improvements in the attenuation of the bundles are required in order to be able to use this technology for medical applications.

  2. Studies of Flerovium and Element 115 Homologs with Macrocyclic Extractants

    Energy Technology Data Exchange (ETDEWEB)

    Despotopulos, John D. [Univ. of Nevada, Las Vegas, NV (United States)

    2015-03-12

    Study of the chemistry of the heaviest elements, Z ≥ 104, poses a unique challenge due to their low production cross-sections and short half-lives. Chemistry also must be studied on the one-atom-at-a-time scale, requiring automated, fast, and very efficient chemical schemes. Recent studies of the chemical behavior of copernicium (Cn, element 112) and flerovium (Fl, element 114) together with the discovery of isotopes of these elements with half-lives suitable for chemical studies have spurred a renewed interest in the development of rapid systems designed to study the chemical properties of elements with Z ≥ 114. This dissertation explores both extraction chromatography and solvent extraction as methods for development of a rapid chemical separation scheme for the homologs of flerovium (Pb, Sn, Hg) and element 115 (Bi, Sb), with the goal of developing a chemical scheme that, in the future, can be applied to on-line chemistry of both Fl and element 115. Carrier-free radionuclides, used in these studies, of the homologs of Fl and element 115 were obtained by proton activation of high-purity metal foils at the Lawrence Livermore National Laboratory (LLNL) Center for Accelerator Mass Spectrometry (CAMS): natIn(p,n)113Sn, natSn(p,n)124Sb, and Au(p,n)197m,gHg. The carrier-free activity was separated from the foils by novel separation schemes based on ion exchange and extraction chromatography techniques. Carrier-free Pb and Bi isotopes were obtained from development of a novel generator based on cation exchange chromatography using the 232U parent to generate 212Pb and 212Bi. Macrocyclic extractants, specifically crown ethers and their derivatives, were chosen for these studies; crown ethers show high selectivity for metal ions. Finally. a potential chemical system for Fl was established based on the Eichrom Pb resin, and insight to an improved system based on thiacrown ethers is

  3. Non-abelian higher gauge theory and categorical bundle

    CERN Document Server

    Viennot, David

    2012-01-01

    A gauge theory is associated with a principal bundle endowed with a connection permitting to define horizontal lifts of paths. The horizontal lifts of surfaces cannot be defined into a principal bundle structure. An higher gauge theory is an attempt to generalize the bundle structure in order to describe horizontal lifts of surfaces. A such attempt is particularly difficult for the non-abelian case. Some structures have been proposed to realize this goal (twisted bundle, gerbes with connection, bundle gerbe, 2-bundle). Each of them uses a category in place of the total space manifold of the usual principal bundle structure. Some of them replace also the structure group by a category (more precisely a Lie crossed module viewed as a category). But the base space remains still a simple manifold (possibly viewed as a trivial category with only identity arrows). We propose a new principal categorical bundle structure, with a Lie crossed module as structure groupoid, but with a base space belonging to a bigger clas...

  4. Presenting Lexical Bundles for Explicit Noticing with Schematic Linguistic Representation

    Science.gov (United States)

    Thomson, Haidee Elizabeth

    2016-01-01

    Lexical bundles are essential for fluency, but their incompleteness is a stumbling block for learners. In this study, two presentation methods to increase awareness of lexical bundles through explicit noticing are explored and compared with incidental exposure. The three conditions in this study were as follows: noticing with schematic linguistic…

  5. Smooth Bundling of Large Streaming and Sequence Graphs

    NARCIS (Netherlands)

    Hurter, C.; Ersoy, O.; Telea, A.

    2013-01-01

    Dynamic graphs are increasingly pervasive in modern information systems. However, understanding how a graph changes in time is difficult. We present here two techniques for simplified visualization of dynamic graphs using edge bundles. The first technique uses a recent image-based graph bundling met

  6. Helical twist controls the thickness of F-actin bundles

    NARCIS (Netherlands)

    Claessens, M.M.A.E.; Semmrich, C.; Ramos, L.; Bausch, A.R.

    2008-01-01

    In the presence of condensing agents such as nonadsorbing polymer, multivalent counter ions, and specific bundling proteins, chiral biopolymers typically form bundles with a finite thickness, rather than phase-separating into a polymer-rich phase. Although short-range repulsive interactions or geome

  7. Lexical Bundles in L1 and L2 Academic Writing

    Science.gov (United States)

    Chen, Yu-Hua; Baker, Paul

    2010-01-01

    This paper adopts an automated frequency-driven approach to identify frequently-used word combinations (i.e., "lexical bundles") in academic writing. Lexical bundles retrieved from one corpus of published academic texts and two corpora of student academic writing (one L1, the other L2), were investigated both quantitatively and qualitatively.…

  8. Lexical Bundles: Facilitating University "Talk" in Group Discussions

    Science.gov (United States)

    Heng, Chan Swee; Kashiha, Hadi; Tan, Helen

    2014-01-01

    Group discussion forms an integral language experience for most language learners, providing them with an opportunity to express themselves in a naturalistic setting. Multi-word expressions are commonly used and one of them is lexical bundles. Lexical bundles are types of extended collocations that occur more commonly than we expect; they are…

  9. Vector bundles of rank 2 computing Clifford indices

    CERN Document Server

    Lange, H

    2010-01-01

    Clifford indices of vector bundles on algebraic curves were introduced in a previous paper of the authors. In this paper we study bundles of rank 2 which compute these Clifford indices. This is of particular interest in the light of recently discovered counterexamples to a conjecture of Mercat.

  10. On the general elephant conjecture for Mori conic bundles

    CERN Document Server

    Prokhorov, Yu G

    1996-01-01

    Let $f:X\\to S$ be an extremal contraction from a threefolds with terminal singularities onto a surface (so called Mori conic bundle). We study some particular cases of such contractions: quotients of usual conic bundles and index two contractions. Assuming Reid's general elephants conjecture we also obtain a rough classification. We present many examples.

  11. Subanalytic Bundles and Tubular Neighbourhoods of Zero-Loci

    Indian Academy of Sciences (India)

    Vishwambhar Pati

    2003-08-01

    We introduce the natural and fairly general notion of a subanalytic bundle (with a finite dimensional vector space of sections) on a subanalytic subset of a real analytic manifold , and prove that when is compact, there is a Baire subset of sections in whose zero-loci in have tubular neighbourhoods, homeomorphic to the restriction of the given bundle to these zero-loci.

  12. Computational imaging through a fiber-optic bundle

    Science.gov (United States)

    Lodhi, Muhammad A.; Dumas, John Paul; Pierce, Mark C.; Bajwa, Waheed U.

    2017-05-01

    Compressive sensing (CS) has proven to be a viable method for reconstructing high-resolution signals using low-resolution measurements. Integrating CS principles into an optical system allows for higher-resolution imaging using lower-resolution sensor arrays. In contrast to prior works on CS-based imaging, our focus in this paper is on imaging through fiber-optic bundles, in which manufacturing constraints limit individual fiber spacing to around 2 μm. This limitation essentially renders fiber-optic bundles as low-resolution sensors with relatively few resolvable points per unit area. These fiber bundles are often used in minimally invasive medical instruments for viewing tissue at macro and microscopic levels. While the compact nature and flexibility of fiber bundles allow for excellent tissue access in-vivo, imaging through fiber bundles does not provide the fine details of tissue features that is demanded in some medical situations. Our hypothesis is that adapting existing CS principles to fiber bundle-based optical systems will overcome the resolution limitation inherent in fiber-bundle imaging. In a previous paper we examined the practical challenges involved in implementing a highly parallel version of the single-pixel camera while focusing on synthetic objects. This paper extends the same architecture for fiber-bundle imaging under incoherent illumination and addresses some practical issues associated with imaging physical objects. Additionally, we model the optical non-idealities in the system to get lower modelling errors.

  13. Parabolic stable Higgs bundles over complete noncompact Riemann surfaces

    Institute of Scientific and Technical Information of China (English)

    李嘉禹; 王友德

    1999-01-01

    Let M be an open Riemann surface with a finite set of punctures, a complete Poincar(?)-like metric is introduced near the punctures and the equivalence between the stability of an indecomposable parabolic Higgs bundle, and the existence of a Hermitian-Einstein metric on the bundle is established.

  14. Lexical Bundles in L1 and L2 Academic Writing

    Science.gov (United States)

    Chen, Yu-Hua; Baker, Paul

    2010-01-01

    This paper adopts an automated frequency-driven approach to identify frequently-used word combinations (i.e., "lexical bundles") in academic writing. Lexical bundles retrieved from one corpus of published academic texts and two corpora of student academic writing (one L1, the other L2), were investigated both quantitatively and qualitatively.…

  15. An integral Riemann-Roch theorem for surface bundles

    DEFF Research Database (Denmark)

    Madsen, Ib Henning

    2010-01-01

    This paper is a response to a conjecture by T. Akita about an integral Riemann–Roch theorem for surface bundles.......This paper is a response to a conjecture by T. Akita about an integral Riemann–Roch theorem for surface bundles....

  16. On the Classification of Complex Vector Bundles of Stable Rank

    Indian Academy of Sciences (India)

    Constantin Bǎnicǎ; Mihai Putinar

    2006-08-01

    One describes, using a detailed analysis of Atiyah–Hirzebruch spectral sequence, the tuples of cohomology classes on a compact, complex manifold, corresponding to the Chern classes of a complex vector bundle of stable rank. This classification becomes more effective on generalized flag manifolds, where the Lie algebra formalism and concrete integrability conditions describe in constructive terms the Chern classes of a vector bundle.

  17. Sceliphrolactam, a polyene macrocyclic lactam from a wasp-associated Streptomyces sp

    DEFF Research Database (Denmark)

    Oh, Dong-Chan; Poulsen, Michael; Currie, Cameron R

    2011-01-01

    A previously unreported 26-membered polyene macrocyclic lactam, sceliphrolactam, was isolated from an actinomycete, Streptomyces sp., associated with the mud dauber, Sceliphron caementarium. Sceliphrolactam's structure was determined by 1D- and 2D-NMR, MS, UV, and IR spectral analysis. Sceliphrol...

  18. New macrocycles with potent antituberculosis activity accessed by one-pot multicomponent reactions

    NARCIS (Netherlands)

    Kim, D.; Huang, Y.; Wang, K.; Doemling, A.

    Based on modeling studies, we hypothesized that tylosin derivatives without formyl group should rather adopt an erythromycin-like binding mode to the ribosome. Twenty four 16-membered macrocyclic compounds were accessed by multicomponent reactions (Gewald, Ugi) of tylosin and investigated for their

  19. Haemonchus contortus P-glycoprotein-2: in situ localisation and characterisation of macrocyclic lactone transport.

    Science.gov (United States)

    Godoy, Pablo; Lian, Jing; Beech, Robin N; Prichard, Roger K

    2015-01-01

    Haemonchus contortus is a veterinary nematode that infects small ruminants, causing serious decreases in animal production worldwide. Effective control through anthelmintic treatment has been compromised by the development of resistance to these drugs, including the macrocyclic lactones. The mechanisms of resistance in H. contortus have yet to be established but may involve efflux of the macrocyclic lactones by nematode ATP-binding-cassette transporters such as P-glycoproteins. Here we report the expression and functional activity of H. contortus P-glycoprotein 2 expressed in mammalian cells and characterise its interaction with the macrocyclic lactones, ivermectin, abamectin and moxidectin. The ability of H. contortus P-glycoprotein 2 to transport different fluorophore substrates was markedly inhibited by ivermectin and abamectin in a dose-dependent and saturable way. The profile of transport inhibition by moxidectin was markedly different. H. contortus P-glycoprotein 2 was expressed in the pharynx, the first portion of the worm's intestine and perhaps in adjacent nervous tissue, suggesting a role for this gene in regulating the uptake of avermectins and in protecting nematode tissues from the effects of macrocyclic lactone anthelmintic drugs. H. contortus P-glycoprotein 2 may thus contribute to resistance to these drugs in H. contortus.

  20. Synthesis of Tetra-Schiff Base Macrocyclic Compound Containing Benzo-12-crown-4

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Tetra-Schiff base macrocyclic compound containing benzo-12-crown-4 was synthesized via condensation of 2, 6-diformyl-4-methyl-phenol with 4(, 5(- diaminobenzo-12-C- 4 promoted by proton. The compound was characterized by MS, IR 1HNMR spectroscopy and elemental analysis.

  1. New Cleft-like Molecules and Macrocycles from Phosphonate Substituted Spirobisindanol

    Directory of Open Access Journals (Sweden)

    Paolo Finocchiaro

    2008-03-01

    Full Text Available We have synthetized medium-sized cyclophanes and macrocycles containingphosphonic groups, directly linked to the aromatic rings of the phanes or as pendant arms,for use as specific receptors for the selective complexation of neutral guests or forcomplexing lanthanides, as luminescent sensors and for diagnostic bioassays in medicine.Furthermore, because it would be of great interest for biochemistry as well as forpharmacological studies to dispose of preorganized rigid chiral hosts for biorelevantmolecules we designed inter alia, some new chiral macrocycles capable of a triple bindingmode and we used them for constructing macrocycles that could also be of interest forchiral recognition and chiral separations. Thus, in this paper we shall review the salientaspects of some macrocycles synthetized in our laboratory, all possessing the phosphonatemoiety and a spirobisindanol scaffold and able to act as complexing agents for cations andorganic substrates. In particular, we shall describe their NMR characterization, theirstereochemistry in solution and in the solid state, and their use as chiral receptors forbiorelevant molecules. Chiral HPLC resolution of some of them is also reported.

  2. Short and diverse route toward complex natural product-like macrocycles.

    NARCIS (Netherlands)

    Beck, Barbara; Larbig, Gregor; Mejat, Beatrice; Magnin-Lachaux, Marina; Picard, Anne; Herdtweck, Eberhardt; Dömling, Alexander

    2003-01-01

    [reaction: see text] A general strategy toward macrocyclic compounds using multicomponent reaction (MCR) chemistry, e.g., Passerini and Ugi variants, and ring-closing metathesis (RCM) is introduced. The corresponding bifunctional isocyanides carboxylic acids bearing a terminal olefin are easy to pre

  3. Structural and Biochemical Basis for Intracellular Kinase Inhibition by Src-specific Peptidic Macrocycles.

    Science.gov (United States)

    Aleem, Saadat; Georghiou, George; Kleiner, Ralph E; Guja, Kip; Craddock, Barbara P; Lyczek, Agatha; Chan, Alix I; Garcia-Diaz, Miguel; Miller, W Todd; Liu, David R; Seeliger, Markus A

    2016-09-22

    Protein kinases are attractive therapeutic targets because their dysregulation underlies many diseases, including cancer. The high conservation of the kinase domain and the evolution of drug resistance, however, pose major challenges to the development of specific kinase inhibitors. We recently discovered selective Src kinase inhibitors from a DNA-templated macrocycle library. Here, we reveal the structural basis for how these inhibitors retain activity against a disease-relevant, drug-resistant kinase mutant, while maintaining Src specificity. We find that these macrocycles display a degree of modularity: two of their three variable groups interact with sites on the kinase that confer selectivity, while the third group interacts with the universally conserved catalytic lysine and thereby retains the ability to inhibit the "gatekeeper" kinase mutant. We also show that these macrocycles inhibit migration of MDA-MB-231 breast tumor cells. Our findings establish intracellular kinase inhibition by peptidic macrocycles, and inform the development of potent and specific kinase inhibitors. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Photoswitchable Dihydroazulene Macrocycles for Solar Energy Storage: The Effects of Ring Strain.

    Science.gov (United States)

    Vlasceanu, Alexandru; Frandsen, Benjamin N; Skov, Anders B; Hansen, Anne Schou; Rasmussen, Mads Georg; Kjaergaard, Henrik G; Mikkelsen, Kurt V; Nielsen, Mogens Brøndsted

    2017-09-11

    Efficient energy storage and release are two major challenges of solar energy harvesting technologies. The development of molecular solar thermal systems presents one approach to address these issues by tuning the isomerization reactions of photo/thermoswitches. Here we show that the incorporation of photoswitches into macrocyclic structures is a particularly attractive solution for increasing the storage time. We present the synthesis and properties of a series of macrocycles incorporating two dihydroazulene (DHA) photoswitching subunits, bridged by linkers of varying chain length. Independent of ring size, all macrocycles exhibit stepwise, light-induced, ring-opening reactions (DHA-DHA to DHA-VHF to VHF-VHF; VHF = vinylheptafulvene) with the first DHA undergoing isomerization with a similar efficiency as the uncyclized parent system while the second (DHA-VHF to VHF-VHF) is significantly slower. The energy-releasing, VHF-to-DHA, ring closures also occur in a stepwise manner and are systematically found to proceed slower in the more strained (smaller) cycles, but in all cases with a remarkably slow conversion of the second VHF to DHA. We managed to increase the half-life of the second VHF-to-DHA conversion from 65 to 202 h at room temperature by simply decreasing the ring size. A computational study reveals the smallest macrocycle to have the most energetic VHF-VHF state and hence highest energy density.

  5. New macrocycles with potent antituberculosis activity accessed by one-pot multicomponent reactions

    NARCIS (Netherlands)

    Kim, D.; Huang, Y.; Wang, K.; Doemling, A.

    2013-01-01

    Based on modeling studies, we hypothesized that tylosin derivatives without formyl group should rather adopt an erythromycin-like binding mode to the ribosome. Twenty four 16-membered macrocyclic compounds were accessed by multicomponent reactions (Gewald, Ugi) of tylosin and investigated for their

  6. Macrocyclic Peptoid–Peptide Hybrids as Inhibitors of Class I Histone Deacetylases

    DEFF Research Database (Denmark)

    Olsen, Christian Adam; Montero, Ana; Leman, Luke J.;

    2012-01-01

    We report the design, synthesis, and biological evaluation of the first macrocyclic peptoid-containing histone deacetylase (HDAC) inhibitors. The compounds selectively inhibit human class I HDAC isoforms in vitro, with no inhibition of the tubulin deacetylase activity associated with class IIb HD...

  7. Bundled automobile insurance coverage and accidents.

    Science.gov (United States)

    Li, Chu-Shiu; Liu, Chwen-Chi; Peng, Sheng-Chang

    2013-01-01

    This paper investigates the characteristics of automobile accidents by taking into account two types of automobile insurance coverage: comprehensive vehicle physical damage insurance and voluntary third-party liability insurance. By using a unique data set in the Taiwanese automobile insurance market, we explore the bundled automobile insurance coverage and the occurrence of claims. It is shown that vehicle physical damage insurance is the major automobile coverage and affects the decision to purchase voluntary liability insurance coverage as a complement. Moreover, policyholders with high vehicle physical damage insurance coverage have a significantly higher probability of filing vehicle damage claims, and if they additionally purchase low voluntary liability insurance coverage, their accident claims probability is higher than those who purchase high voluntary liability insurance coverage. Our empirical results reveal that additional automobile insurance coverage information can capture more driver characteristics and driving behaviors to provide useful information for insurers' underwriting policies and to help analyze the occurrence of automobile accidents.

  8. On The Motive of G-bundles

    CERN Document Server

    Habibi, Somayeh

    2011-01-01

    Let $G$ be a reductive algebraic group over a perfect field $k$ and $\\mathcal{G}$ a $G$-bundle over a scheme $X/k$. The main aim of this article is to study the motive associated with $\\mathcal{G}$, inside the Veovodsky Motivic categories. We consider the case that $\\charakt k=0$ (resp. $\\charakt k\\geq 0$), the motive associated to $X$ is geometrically mixed Tate (resp. geometrically cellular) and $\\mathcal{G}$ is locally trivial for the Zariski (resp. \\'etale) topology on $X$ and show that the motive of $\\mathcal{G}$ is a geometrically mixed Tate motive. Moreover for a general $X$ we construct a filtration on the motive associated to $\\mathcal{G}$ in terms of weight polytopes. Along the way we give some applications and examples.

  9. Fiber bundle model under fluid pressure

    Science.gov (United States)

    Amitrano, David; Girard, Lucas

    2016-03-01

    Internal fluid pressure often plays an important role in the rupture of brittle materials. This is a major concern for many engineering applications and for natural hazards. More specifically, the mechanisms through which fluid pressure, applied at a microscale, can enhance the failure at a macroscale and accelerate damage dynamics leading to failure remains unclear. Here we revisit the fiber bundle model by accounting for the effect of fluid under pressure that contributes to the global load supported by the fiber bundle. Fluid pressure is applied on the broken fibers, following Biot's theory. The statistical properties of damage avalanches and their evolution toward macrofailure are analyzed for a wide range of fluid pressures. The macroscopic strength of the new model appears to be strongly controlled by the action of the fluid, particularly when the fluid pressure becomes comparable with the fiber strength. The behavior remains consistent with continuous transition, i.e., second order, including for large pressure. The main change concerns the damage acceleration toward the failure that is well modeled by the concept of sweeping of an instability. When pressure is increased, the exponent β characterizing the power-law distribution avalanche sizes significantly decreases and the exponent γ characterizing the cutoff divergence when failure is approached significantly increases. This proves that fluid pressure plays a key role in failure process acting as destabilization factor. This indicates that macrofailure occurs more readily under fluid pressure, with a behavior that becomes progressively unstable as fluid pressure increases. This may have considerable consequences on our ability to forecast failure when fluid pressure is acting.

  10. Artificial ciliary bundles with nano fiber tip links

    CERN Document Server

    Asadnia, Mohsen; Miao, Jianmin; Triantafyllou, Michael

    2015-01-01

    Mechanosensory ciliary bundles in fishes are the inspiration for carefully engineered artificial flow sensors. We report the development of a new class of ultrasensitive MEMS flow sensors that mimic the intricate morphology of the ciliary bundles, including the stereocilia, tip links, and the cupula, and thereby achieve threshold detection limits that match the biological example. An artificial ciliary bundle is achieved by fabricating closely-spaced arrays of polymer micro-pillars with gradiating heights. Tip links that form the fundamental sensing elements are realized through electrospinning aligned PVDF piezoelectric nano-fibers that link the distal tips of the polymer cilia. An optimized synthesis of hyaluronic acid-methacrylic anhydride hydrogel that results in properties close to the biological cupula, together with drop-casting method are used to form the artificial cupula that encapsulates the ciliary bundle. In testing, fluid drag force causes the ciliary bundle to slide, stretching the flexible nan...

  11. HORIZONTAL LAPLACE OPERATOR IN REAL FINSLER VECTOR BUNDLES

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A vector bundle F over the tangent bundle TM of a manifold M is said to be a Finsler vector bundle if it is isomorphic to the pull-back π*E of a vector bundle E over M([1]). In this article the authors study the h-Laplace operator in Finsler vector bundles.An h-Laplace operator is defined, first for functions and then for horizontal Finsler forms on E. Using the h-Laplace operator, the authors define the h-harmonic function and h-harmonic horizontal Finsler vector fields, and furthermore prove some integral formulas for the h-Laplace operator, horizontal Finsler vector fields, and scalar fields on E.

  12. The 2-Hilbert Space of a Prequantum Bundle Gerbe

    CERN Document Server

    Bunk, Severin; Szabo, Richard J

    2016-01-01

    We construct a prequantum 2-Hilbert space for any line bundle gerbe whose Dixmier-Douady class is torsion. Analogously to usual prequantisation, this 2-Hilbert space has the category of sections of the line bundle gerbe as its underlying 2-vector space. These sections are obtained as certain morphism categories in Waldorf's version of the 2-category of line bundle gerbes. We show that these morphism categories carry a monoidal structure under which they are semisimple and abelian. We introduce a dual functor on the sections, which yields a closed structure on the morphisms between bundle gerbes and turns the category of sections into a 2-Hilbert space. We discuss how these 2-Hilbert spaces fit various expectations from higher prequantisation. We then extend the transgression functor to the full 2-category of bundle gerbes and demonstrate its compatibility with the additional structures introduced. We discuss various aspects of Kostant-Souriau prequantisation in this setting, including its dimensional reductio...

  13. Bundles over Quantum RealWeighted Projective Spaces

    Directory of Open Access Journals (Sweden)

    Tomasz Brzeziński

    2012-09-01

    Full Text Available The algebraic approach to bundles in non-commutative geometry and the definition of quantum real weighted projective spaces are reviewed. Principal U(1-bundles over quantum real weighted projective spaces are constructed. As the spaces in question fall into two separate classes, the negative or odd class that generalises quantum real projective planes and the positive or even class that generalises the quantum disc, so do the constructed principal bundles. In the negative case the principal bundle is proven to be non-trivial and associated projective modules are described. In the positive case the principal bundles turn out to be trivial, and so all the associated modules are free. It is also shown that the circle (coactions on the quantum Seifert manifold that define quantum real weighted projective spaces are almost free.

  14. A geometric approach to noncommutative principal torus bundles

    DEFF Research Database (Denmark)

    Wagner, Stefan

    2013-01-01

    for noncommutative algebras and say that a dynamical system (A, 핋n,α) is called a noncommutative principal 핋n-bundle, if localization leads to a trivial noncommutative principal 핋n-bundle. We prove that this approach extends the classical theory of principal torus bundles and present a bunch of (nontrivial......A (smooth) dynamical system with transformation group 핋n is a triple (A, 핋n,α), consisting of a unital locally convex algebra A, the n-torus 핋n and a group homomorphism α:핋n→Aut(A), which induces a (smooth) continuous action of 핋n on A. In this paper, we present a new, geometrically oriented...... approach to the noncommutative geometry of principal torus bundles based on such dynamical systems. Our approach is inspired by the classical setting: In fact, after recalling the definition of a trivial noncommutative principal torus bundle, we introduce a convenient (smooth) localization method...

  15. Morse theory for the space of Higgs G-bundles

    CERN Document Server

    Biswas, Indranil

    2010-01-01

    Fix a $C^\\infty$ principal $G$--bundle $E^0_G$ on a compact connected Riemann surface $X$, where $G$ is a connected complex reductive linear algebraic group. We consider the gradient flow of the Yang--Mills--Higgs functional on the cotangent bundle of the space of all smooth connections on $E^0_G$. We prove that this flow preserves the subset of Higgs $G$--bundles, and, furthermore, the flow emanating from any point of this subset has a limit. Given a Higgs $G$--bundle, we identify the limit point of the integral curve passing through it. These generalize the results of the second named author on Higgs vector bundles.

  16. [Bundle-branch block depending on the heart rate].

    Science.gov (United States)

    Apostolov, L

    1975-01-01

    Five patients are reported, admitted to the hospital, with diseases predominantly of the cardio-vascular system. During the electrocardiographic examinations bundle branch block was established, depending on heart rate. It fluctuated within the physiological limits from 50 to 90/min. In three of the patients, the bundle branch block appeared with the quickening of the heart rate (tachycardia-depending bundle branch block) and in two of the patients--the bundle branch block appeared during the slowing down of the heart action and disappeared with its quickening (bradicardia-depending bundle branch block). A brief literature review is presented and attention is paid to the possible diagnostic errors and the treatment mode of those patients with cardiac tonic and antiarrhythmic medicaments.

  17. Voltage- and calcium-dependent motility of saccular hair bundles

    Science.gov (United States)

    Quiñones, Patricia M.; Meenderink, Sebastiaan W. F.; Bozovic, Dolores

    2015-12-01

    Active bundle motility, which is hypothesized to supply feedback for mechanical amplification of signals, is thought to enhance sensitivity and sharpen tuning in vestibular and auditory organs. To study active hair bundle motility, we combined high-speed camera recordings of bullfrog sacculi, which were mounted in a two-compartment chamber, and voltage-clamp of the hair cell membrane potential. Using this paradigm, we measured three types of bundle motions: 1) spontaneous oscillations which can be analyzed to measure the physiological operating range of the transduction channel; 2) a sustained quasi-static movement of the bundle that depends on membrane potential; and 3) a fast, transient and asymmetric movement that resets the bundle position and depends on changes in the membrane potential. These data support a role for both calcium and voltage in the transduction-channel function.

  18. Superconductivity in an Inhomogeneous Bundle of Metallic and Semiconducting Nanotubes

    Directory of Open Access Journals (Sweden)

    Ilya Grigorenko

    2013-01-01

    Full Text Available Using Bogoliubov-de Gennes formalism for inhomogeneous systems, we have studied superconducting properties of a bundle of packed carbon nanotubes, making a triangular lattice in the bundle's transverse cross-section. The bundle consists of a mixture of metallic and doped semiconducting nanotubes, which have different critical transition temperatures. We investigate how a spatially averaged superconducting order parameter and the critical transition temperature depend on the fraction of the doped semiconducting carbon nanotubes in the bundle. Our simulations suggest that the superconductivity in the bundle will be suppressed when the fraction of the doped semiconducting carbon nanotubes will be less than 0.5, which is the percolation threshold for a two-dimensional triangular lattice.

  19. CHF Enhancement of Advanced 37-Element Fuel Bundles

    Directory of Open Access Journals (Sweden)

    Joo Hwan Park

    2015-01-01

    Full Text Available A standard 37-element fuel bundle (37S fuel bundle has been used in commercial CANDU reactors for over 40 years as a reference fuel bundle. Most CHF of a 37S fuel bundle have occurred at the elements arranged in the inner pitch circle for high flows and at the elements arranged in the outer pitch circle for low flows. It should be noted that a 37S fuel bundle has a relatively small flow area and high flow resistance at the peripheral subchannels of its center element compared to the other subchannels. The configuration of a fuel bundle is one of the important factors affecting the local CHF occurrence. Considering the CHF characteristics of a 37S fuel bundle in terms of CHF enhancement, there can be two approaches to enlarge the flow areas of the peripheral subchannels of a center element in order to enhance CHF of a 37S fuel bundle. To increase the center subchannel areas, one approach is the reduction of the diameter of a center element, and the other is an increase of the inner pitch circle. The former can increase the total flow area of a fuel bundle and redistributes the power density of all fuel elements as well as the CHF. On the other hand, the latter can reduce the gap between the elements located in the middle and inner pitch circles owing to the increasing inner pitch circle. This can also affect the enthalpy redistribution of the fuel bundle and finally enhance CHF or dry-out power. In this study, the above two approaches, which are proposed to enlarge the flow areas of the center subchannels, were considered to investigate the impact of the flow area changes of the center subchannels on the CHF enhancement as well as the thermal characteristics by applying a subchannel analysis method.

  20. Tren centered tris-macrocycles as polytopic ligands for Cu(II) and Ni(II).

    Science.gov (United States)

    Siegfried, Liselotte; McMahon, C Niamh; Kaden, Thomas A; Palivan, Cornelia; Gescheidt, Georg

    2004-07-21

    Two novel symmetric polytopic ligands L(1) and L(2) have been synthesized. They are composed of three 1,4,8,11-tetraazacyclotetradecane macrocycles which are connected to a central tren moiety via an ethylene and a trimethylene bridge, respectively. The complexation potential and the speciation diagrams of L(1) and L(2) towards Cu(2+) and Ni(2+) were determined by spectrophotometric and potentiometric titrations. Insight into the geometry of the Cu(2+) complexes is provided by UV-VIS and EPR spectroscopy. The simplified ligands L(3) and L(4) are utilized as references for an aminoethyl- and a tren-substituted tetraaza macrocycle to help assign the EPR spectra of the polytopic ligands L(1) and L(2). At a metal-to-ligand ratio of 3 : 1, the metal cations are preferentially bound to the tetraaza macrocycles of L(1) and L(2) in a square planar geometry. At high pH values, a nitrogen atom of the tren moiety in L(1) serves as an additional ligand in an axial position leading to a square pyramidal coordination around Cu(2+), whereas in L(2) no such geometry change is observed. At a metal-to-ligand ratio of 4 : 1, the additional metal cation resides in the central tren moiety of L(1) and L(2). However, in contrast to the typical trigonal bipyramidal geometry found in the [Cutren](2+) complex, the fourth Cu(2+) has a square pyramidal coordination caused by the interaction with the Cu(2+) cations in the macrocycles (as evidenced by EPR spectra). Since the sequence of metal complexation is such that the first three metal ions always bind to the three macrocycles of L(1) and L(2) and the fourth to the tren unit, it is possible to prepare heteronuclear complexes such as [Cu(3)NiL](8+) or [Ni(3)CuL](8+), which can be unambiguously identified by their spectral properties.

  1. Restriction of Preferences to the Set of Consumption Bundles, In a Model with Production and Consumption Bundles

    NARCIS (Netherlands)

    Schalk, S.

    1999-01-01

    In contrast to the neo-classical theory of Arrow and Debreu, a model of a private ownership economy is presented, in which production and consumption bundles are treated separately. Each of the two types of bundles is assumed to establish a con- vex cone. Production technologies can convert producti

  2. Restriction of Preferences to the Set of Consumption Bundles, In a Model with Production and Consumption Bundles

    NARCIS (Netherlands)

    Schalk, S.

    1999-01-01

    In contrast to the neo-classical theory of Arrow and Debreu, a model of a private ownership economy is presented, in which production and consumption bundles are treated separately. Each of the two types of bundles is assumed to establish a con- vex cone. Production technologies can convert

  3. From 2 + 2 to 8 + 8 Condensation Products of Diamine and Dialdehyde: Giant Container-Shaped Macrocycles for Multiple Anion Binding.

    Science.gov (United States)

    Gregoliński, Janusz; Ślepokura, Katarzyna; Paćkowski, Tomasz; Panek, Jarosław; Stefanowicz, Piotr; Lisowski, Jerzy

    2016-07-01

    The combination of 2,6-diformylpyridine and trans-1,2-diaminocyclopentane fragments results in 2 + 2, 3 + 3, 4 + 4, 6 + 6, and 8 + 8 macrocyclic imine condensation products. These imines can be reduced to the corresponding 2 + 2, 3 + 3, 4 + 4, 6 + 6, and 8 + 8 macrocyclic amines. The X-ray crystal structures of their protonated derivatives show a rich variety of macrocycle conformations ranging from a stepped 2 + 2 macrocycle to a multiply folded 8 + 8 macrocycle of globular shape. These compounds bind anions via hydrogen bonds: two chloride anions are bound above and below the macrocyclic ring of the 2 + 2 amine, one chloride anion is bound approximately in the center of the 3 + 3 macrocycle, and two chloride anions are deeply buried inside a folded container-shaped 4 + 4 macrocycle, while in the case of the previously reported 6 + 6 amine four chloride anions and two solvent molecules are buried inside a container-shaped macrocycle. Yet another situation was observed for a multiply folded protonated 8 + 8 macrocycle which binds six sulfate anions; two of them are deeply buried inside the container structure while four anions interact with the clefts at the surface of the container.

  4. Bundling Actin Filaments From Membranes: Some Novel Players

    Directory of Open Access Journals (Sweden)

    Clément eThomas

    2012-08-01

    Full Text Available Progress in live-cell imaging of the cytoskeleton has significantly extended our knowledge about the organization and dynamics of actin filaments near the plasma membrane of plant cells. Noticeably, two populations of filamentous structures can be distinguished. On the one hand, fine actin filaments which exhibit an extremely dynamic behavior basically characterized by fast polymerization and prolific severing events, a process referred to as actin stochastic dynamics. On the other hand, thick actin bundles which are composed of several filaments and which are comparatively more stable although they constantly remodel as well. There is evidence that the actin cytoskeleton plays critical roles in trafficking and signaling at both the cell cortex and organelle periphery but the exact contribution of actin bundles remains unclear. A common view is that actin bundles provide the long-distance tracks used by myosin motors to deliver their cargo to growing regions and accordingly play a particularly important role in cell polarization. However, several studies support that actin bundles are more than simple passive highways and display multiple and dynamic roles in the regulation of many processes, such as cell elongation, polar auxin transport, stomatal and chloroplast movement, and defense against pathogens. The list of identified plant actin-bundling proteins is ever expanding, supporting that plant cells shape structurally and functionally different actin bundles. Here I review the most recently characterized actin-bundling proteins, with a particular focus on those potentially relevant to membrane trafficking and/or signaling.

  5. Novel antibiotics: C-2 symmetrical macrocycles inhibiting Holliday junction DNA binding by E. coli RuvC.

    Science.gov (United States)

    Pan, Po-Shen; Curtis, Fiona A; Carroll, Chris L; Medina, Irene; Liotta, Lisa A; Sharples, Gary J; McAlpine, Shelli R

    2006-07-15

    Holliday junctions (HJs) are formed as transient DNA intermediates during site-specific and homologous recombination. Both of these genetic exchange pathways are critical for normal DNA metabolism and repair. Trapping HJs leads to bacterial cell death by preventing proper segregation of the resulting interlinked chromosomes. Macrocyclic peptides designed to target this intermediate were synthesized with the goal of identifying compounds with specificity for this unique molecular target. We discovered ten macrocycles, both hexameric and octameric peptides, capable of trapping HJs in vitro. Those macrocycles containing tyrosine residues proved most effective. These data demonstrate that C-2 symmetrical macrocycles offer excellent synthetic targets for the development of novel antibiotic agents. Furthermore, the active compounds identified provide valuable tools for probing different pathways of recombinational exchange.

  6. Bondage Numbers of C4 Bundles over a Cycle Cn

    Directory of Open Access Journals (Sweden)

    Moo Young Sohn

    2013-01-01

    Full Text Available Graph bundles generalize the notion of covering graphs and graph products. Graph bundles have been applied in computer architecture and communication networks. The bondage number is an important parameter for measuring the vulnerability and stability of the network domination under link failure. The bondage number b(G of a graph G is the minimum number of edges whose removal enlarges the domination number. In this paper, we show that the bondage number of every C4 bundles over a cycle Cn  (n≥4 is equal to 4.

  7. The Born rule as structure of spectral bundles (extended abstract

    Directory of Open Access Journals (Sweden)

    Bertfried Fauser

    2012-10-01

    Full Text Available Topos approaches to quantum foundations are described in a unified way by means of spectral bundles, where the base space is a space of contexts and each fibre is its spectrum. Differences in variance are due to the bundle being a fibration or opfibration. Relative to this structure, the probabilistic predictions of the Born rule in finite dimensional settings are then described as a section of a bundle of valuations. The construction uses in an essential way the geometric nature of the valuation locale monad.

  8. —Impact of Customer Knowledge Heterogeneity on Bundling Strategy

    OpenAIRE

    Amiya Basu; Padmal Vitharana

    2009-01-01

    We consider a marketer of components who can select one of three alternative pricing strategies: (1) a pure component strategy (i.e., the customer can only buy the components individually), (2) a pure bundling strategy (i.e., the components must be purchased together), or (3) a mixed bundling strategy (i.e., the customer may buy a component individually, or buy the bundle). We consider a market where customer knowledge of components varies and propose that a high-knowledge customer can determ...

  9. Systematic evaluation of bundled SPC water for biomolecular simulations.

    Science.gov (United States)

    Gopal, Srinivasa M; Kuhn, Alexander B; Schäfer, Lars V

    2015-04-07

    In bundled SPC water models, the relative motion of groups of four water molecules is restrained by distance-dependent potentials. Bundled SPC models have been used in hybrid all-atom/coarse-grained (AA/CG) multiscale simulations, since they enable to couple atomistic SPC water with supra-molecular CG water models that effectively represent more than a single water molecule. In the present work, we systematically validated and critically tested bundled SPC water models as solvent for biomolecular simulations. To that aim, we investigated both thermodynamic and structural properties of various biomolecular systems through molecular dynamics (MD) simulations. Potentials of mean force of dimerization of pairs of amino acid side chains as well as hydration free energies of single side chains obtained with bundled SPC and standard (unrestrained) SPC water agree closely with each other and with experimental data. Decomposition of the hydration free energies into enthalpic and entropic contributions reveals that in bundled SPC, this favorable agreement of the free energies is due to a larger degree of error compensation between hydration enthalpy and entropy. The Ramachandran maps of Ala3, Ala5, and Ala7 peptides are similar in bundled and unrestrained SPC, whereas for the (GS)2 peptide, bundled water leads to a slight overpopulation of extended conformations. Analysis of the end-to-end distance autocorrelation times of the Ala5 and (GS)2 peptides shows that sampling in more viscous bundled SPC water is about two times slower. Pronounced differences between the water models were found for the structure of a coiled-coil dimer, which is instable in bundled SPC but not in standard SPC. In addition, the hydration of the active site of the serine protease α-chymotrypsin depends on the water model. Bundled SPC leads to an increased hydration of the active site region, more hydrogen bonds between water and catalytic triad residues, and a significantly slower exchange of water

  10. Ring-closing metathesis for the synthesis of a highly G-quadruplex selective macrocyclic hexaoxazole having enhanced cytotoxic potency.

    Science.gov (United States)

    Satyanarayana, Mavurapu; Rzuczek, Suzanne G; Lavoie, Edmond J; Pilch, Daniel S; Liu, Angela; Liu, Leroy F; Rice, Joseph E

    2008-07-01

    The synthesis of a 24-membered macrocyclic hexaoxazole via ring-closing metathesis is described. The target compound selectively stabilizes G-quadruplex DNA with no detectable stabilization of duplex DNA. An MTT cytotoxicity assay indicated that this unsaturated macrocyclic hexaoxazole exhibits significant cytotoxicity toward P388, RPMI 8402, and KB3-1 cell lines with IC50 values of 45, 25, and 38 nM, respectively.

  11. The effect of hair bundle shape on hair bundle hydrodynamics of inner ear hair cells at low and high frequencies.

    Science.gov (United States)

    Shatz, L F

    2000-03-01

    The relationship between size and shape of the hair bundle of a hair cell in the inner ear and its sensitivity at asymptotically high and low frequencies was determined, thereby extending the results of an analysis of hair bundle hydrodynamics in two dimensions (Freeman and Weiss, 1990. Hydrodynamic analysis of a two-dimensional model for micromechanical resonance of free-standing hair bundles. Hear. Res. 48, 37-68) to three dimensions. A hemispheroid was used to represent the hair bundle. The hemispheroid had a number of advantages: it could represent shapes that range from thin, pencil-like shapes, to wide, flat, disk-like shapes. Also analytic methods could be used in the high frequency range to obtain an exact solution to the equations of motion. In the low frequency range, where an approximate solution was found using boundary element methods, the sensitivity of the responses of hair cells was mainly proportional to the cube of the heights of their hair bundles, and at high frequencies, the sensitivity of the hair cells was mainly proportional to the inverse of their heights. An excellent match was obtained between measurements of sensitivity curves in the basillar papilla of the alligator and bobtail lizards and the model's predictions. These results also suggest why hair bundles of hair cells in vestibular organs which are sensitive to low frequencies have ranges of heights that are an order of magnitude larger than the range of heights of hair bundles of hair cells found in auditory organs.

  12. A study of bacterial flagellar bundling.

    Science.gov (United States)

    Flores, Heather; Lobaton, Edgar; Méndez-Diez, Stefan; Tlupova, Svetlana; Cortez, Ricardo

    2005-01-01

    Certain bacteria, such as Escherichia coli (E. coli) and Salmonella typhimurium (S. typhimurium), use multiple flagella often concentrated at one end of their bodies to induce locomotion. Each flagellum is formed in a left-handed helix and has a motor at the base that rotates the flagellum in a corkscrew motion. We present a computational model of the flagellar motion and their hydrodynamic interaction. The model is based on the equations of Stokes flow to describe the fluid motion. The elasticity of the flagella is modeled with a network of elastic springs while the motor is represented by a torque at the base of each flagellum. The fluid velocity due to the forces is described by regularized Stokeslets and the velocity due to the torques by the associated regularized rotlets. Their expressions are derived. The model is used to analyze the swimming motion of a single flagellum and of a group of three flagella in close proximity to one another. When all flagellar motors rotate counterclockwise, the hydrodynamic interaction can lead to bundling. We present an analysis of the flow surrounding the flagella. When at least one of the motors changes its direction of rotation, the same initial conditions lead to a tumbling behavior characterized by the separation of the flagella, changes in their orientation, and no net swimming motion. The analysis of the flow provides some intuition for these processes.

  13. Nursing Care Management: Influence on Bundled Payments.

    Science.gov (United States)

    Lentz, Shaynie; Luther, Brenda

    Fragmented and uncoordinated care is the third highest driver of U.S. healthcare costs. Although less than 10% of patients experience uncoordinated care, these patients represent 36% of total healthcare costs; care management interaction makes a significant impact on the utilization of healthcare dollars. A literature search was conducted to construct a model of care coordination for elective surgical procedures by collecting best practices for acute, transitions, and post-acute care periods. A case study was used to demonstrate the model developed. Care management defines care coordination as a model of care to address improving patient and caregiver engagement, communication across settings of care, and ultimately improved patient outcomes of care. Nurse-led care coordination in the presurgical, inpatient, and post-acute care settings requires systems change and administrative support to effectively meet the goals of the Affordable Care Act of reducing redundancy and costs while improving the patient experience. Nursing is the lynchpin of care management processes in all settings of care; thus, this model of care coordination for elective surgical admissions can provide nursing care management leaders a comprehensive view of coordinating care for these patient across settings of care during the predetermined time period of care. As bundled payment structures increasingly affect hospital systems, nursing leaders need to be ready to create or improve their care management processes; care coordination is one such process requiring immediate attention.

  14. LVRF fuel bundle manufacture for Bruce

    Energy Technology Data Exchange (ETDEWEB)

    Pant, A. [Zircatec Precision Industries, Port Hope, Ontario (Canada)

    2005-12-15

    In response to the Power Uprate program at Bruce Power, Zircatec has committed to introduce, by Spring 2006 a new manufacturing line for the production of 43 element Bruce LVRF bundles containing Slightly Enriched Uranium (SEU) with a centre pin of blended dysprosia/urania (BDU). This is a new fuel design and is the first change in fuel design since the introduction of the current 37-element fuel over 20 years ago. Introduction of this new line has involved the introduction of significant changes to an environment that is not used to rapid changes with significant impact. At ZPI we have been able to build on our innovative capabilities in new fuel manufacturing, the strength and experience of our core team, and on our prevailing management philosophy of 'support the doer'. The presentation will discuss some of the novel aspects of this fuel introduction and the mix of innovative and classical project management methods that are being used to ensure that project deliveries are being met. Supporting presentations will highlight some of the issues in more detail. (author)

  15. The addition of a second lanthanide ion to increase the luminescence of europium(III) macrocyclic complexes

    Energy Technology Data Exchange (ETDEWEB)

    Bromm, A.J. Jr.; Vallarino, L.M. [Virginia Commonwealth Univ., Richmond, VA (United States). Dept. of Chemistry; Leif, R.C. [Newport Instruments, San Diego, CA (United States); Quagliano, J.R. [Los Alamos National Lab., NM (United States)

    1998-12-29

    At present, the microscopic visualization of luminescent labels containing lanthanide(III) ions, primarily europium(III), as light-emitting centers is best performed with time-gated instrumentation, which by virtually eliminating the background fluorescence results in an improved signal to noise ratio. However, the use of the europium(III) macrocycle, Quantum Dye{trademark}, in conjunction with the strong luminescence enhancing effect (cofluorescence) of yttrium(III) or gadolinium(III), can eliminate the need for such specialized instrumentation. In the presence of Gd(III), the luminescence of the Eu(III)-macrocycles can be conveniently observed with conventional fluorescence instrumentation at previously unattainable low levels. The Eu(III) {sup 5}D{sub 0} {r_arrow} {sup 7}F{sub 2} emission of the Eu(III)-macrocycles was observed as an extremely sharp band with a maximum at 619 nm and a clearly resolved characteristic pattern. At very low Eu(III)-macrocycle concentrations, another sharp emission was detected at 614 nm, arising from traces of Eu(III) present in even the purest commercially available gadolinium products. Discrimination of the resolved emissions of the Eu(III)-macrocycle and Eu(III) contaminant should provide a means to further lower the limit of detection of the Eu(III)-macrocycle.

  16. Zeta Functions for Elliptic Curves I. Counting Bundles

    CERN Document Server

    Weng, Lin

    2012-01-01

    To count bundles on curves, we study zetas of elliptic curves and their zeros. There are two types, i.e., the pure non-abelian zetas defined using moduli spaces of semi-stable bundles, and the group zetas defined for special linear groups. In lower ranks, we show that these two types of zetas coincide and satisfy the Riemann Hypothesis. For general cases, exposed is an intrinsic relation on automorphism groups of semi-stable bundles over elliptic curves, the so-called counting miracle. All this, together with Harder-Narasimhan, Desale-Ramanan and Zagier's result, gives an effective way to count semi-stable bundles on elliptic curves not only in terms of automorphism groups but more essentially in terms of their $h^0$'s. Distributions of zeros of high rank zetas are also discussed.

  17. Bundles of Norms About Teen Sex and Pregnancy.

    Science.gov (United States)

    Mollborn, Stefanie; Sennott, Christie

    2015-09-01

    Teen pregnancy is a cultural battleground in struggles over morality, education, and family. At its heart are norms about teen sex, contraception, pregnancy, and abortion. Analyzing 57 interviews with college students, we found that "bundles" of related norms shaped the messages teens hear. Teens did not think their communities encouraged teen sex or pregnancy, but normative messages differed greatly, with either moral or practical rationalizations. Teens readily identified multiple norms intended to regulate teen sex, contraception, abortion, childbearing, and the sanctioning of teen parents. Beyond influencing teens' behavior, norms shaped teenagers' public portrayals and post hoc justifications of their behavior. Although norm bundles are complex to measure, participants could summarize them succinctly. These bundles and their conflicting behavioral prescriptions create space for human agency in negotiating normative pressures. The norm bundles concept has implications for teen pregnancy prevention policies and can help revitalize social norms for understanding health behaviors.

  18. Design and synthesis of DNA four-helix bundles

    Energy Technology Data Exchange (ETDEWEB)

    Rangnekar, Abhijit; Gothelf, Kurt V [Department of Chemistry, Centre for DNA Nanotechnology (CDNA) and Interdisciplinary Nanoscience Center (iNANO), Aarhus University, DK-8000 Aarhus C (Denmark); LaBean, Thomas H, E-mail: kvg@chem.au.dk, E-mail: thl@cs.duke.edu [Department of Chemistry, Duke University, Durham, NC 27708 (United States)

    2011-06-10

    The field of DNA nanotechnology has evolved significantly in the past decade. Researchers have succeeded in synthesizing tile-based structures and using them to form periodic lattices in one, two and three dimensions. Origami-based structures have also been used to create nanoscale structures in two and three dimensions. Design and construction of DNA bundles with fixed circumference has added a new dimension to the field. Here we report the design and synthesis of a DNA four-helix bundle. It was found to be extremely rigid and stable. When several such bundles were assembled using appropriate sticky-ends, they formed micrometre-long filaments. However, when creation of two-dimensional sheet-like arrays of the four-helix bundles was attempted, nanoscale rings were observed instead. The exact reason behind the nanoring formation is yet to be ascertained, but it provides an exciting prospect for making programmable circular nanostructures using DNA.

  19. CANFLEX fuel bundle cross-flow endurance test (test report)

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Sung Deok; Chung, C. H.; Chang, S. K.; Kim, B. D.

    1997-04-01

    As part of the normal refuelling sequence of CANDU nuclear reactor, both new and irradiated bundles can be parked in the cross-flow region of the liner tubes. This situation occurs normally for a few minutes. The fuel bundle which is subjected to the cross-flow should be capable of withstanding the consequences of cross flow for normal periods, and maintain its mechanical integrity. The cross-flow endurance test was conducted for CANFLEX bundle, latest developed nuclear fuel, at CANDU-Hot Test Loop. The test was carried out during 4 hours at the inlet cross-flow region. After the test, the bundle successfully met all acceptance criteria after the 4 hours cross-flow test. (author). 2 refs., 3 tabs.

  20. On exact triangles consisting of stable vector bundles on tori

    CERN Document Server

    Kobayashi, Kazushi

    2016-01-01

    In this paper, we consider the exact triangles consisting of stable holomorphic vector bundles on one-dimensional complex tori, and discuss their relations with the corresponding Fukaya category via the homological mirror symmetry.

  1. Steric effects induce geometric remodeling of actin bundles in filopodia

    CERN Document Server

    Dobramysl, Ulrich; Erban, Radek

    2016-01-01

    Filopodia are ubiquitous fingerlike protrusions, spawned by many eukaryotic cells, to probe and interact with their environments. Polymerization dynamics of actin filaments, comprising the structural core of filopodia, largely determine their instantaneous lengths and overall lifetimes. The polymerization reactions at the filopodial tip require transport of G-actin, which enter the filopodial tube from the filopodial base and diffuse toward the filament barbed ends near the tip. Actin filaments are mechanically coupled into a tight bundle by cross-linker proteins. Interestingly, many of these proteins are relatively short, restricting the free diffusion of cytosolic G-actin throughout the bundle and, in particular, its penetration into the bundle core. To investigate the effect of steric restrictions on G-actin diffusion by the porous structure of filopodial actin filament bundle, we used a particle-based stochastic simulation approach. We discovered that excluded volume interactions result in partial and the...

  2. Mechanical Models of Microtubule Bundle Collapse in Alzheimer's Disease

    Science.gov (United States)

    Sendek, Austin; Singh, Rajiv; Cox, Daniel

    2013-03-01

    Amyloid-beta aggregates initiate Alzheimer's disease, and downstream trigger degradation of tau proteins that act as microtubule bundle stabilizers and mechanical spacers. Currently it is unclear which of tau cutting by proteases, tau phosphorylation, or tau aggregation are responsible for cytoskeleton degradation., We construct a percolation simulation of the microtubule bundle using a molecular spring model for the taus and including depletion force attraction between microtubules and membrane/actin cytoskeletal surface tension. The simulation uses a fictive molecular dynamics to model the motion of the individual microtubules within the bundle as a result of random tau removal, and calculates the elastic modulus of the bundle as the tau concentration falls. We link the tau removal steps to kinetic tau steps in various models of tau degradation. Supported by US NSF Grant DMR 1207624

  3. Introductory lectures on fibre bundles and topology for physicists

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, G.H.

    1978-05-01

    These lectures may provide useful background material for understanding gauge theories, particularly the nonperturbative effects such as instantons and monopoles. The mathematical language of topology and fibre bundles is introduced.

  4. Improved Conjugate Gradient Bundle Adjustment of Dunhuang Wall Painting Images

    Science.gov (United States)

    Hu, K.; Huang, X.; You, H.

    2017-09-01

    Bundle adjustment with additional parameters is identified as a critical step for precise orthoimage generation and 3D reconstruction of Dunhuang wall paintings. Due to the introduction of self-calibration parameters and quasi-planar constraints, the structure of coefficient matrix of the reduced normal equation is banded-bordered, making the solving process of bundle adjustment complex. In this paper, Conjugate Gradient Bundle Adjustment (CGBA) method is deduced by calculus of variations. A preconditioning method based on improved incomplete Cholesky factorization is adopt to reduce the condition number of coefficient matrix, as well as to accelerate the iteration rate of CGBA. Both theoretical analysis and experimental results comparison with conventional method indicate that, the proposed method can effectively conquer the ill-conditioned problem of normal equation and improve the calculation efficiency of bundle adjustment with additional parameters considerably, while maintaining the actual accuracy.

  5. IMPROVED CONJUGATE GRADIENT BUNDLE ADJUSTMENT OF DUNHUANG WALL PAINTING IMAGES

    Directory of Open Access Journals (Sweden)

    K. Hu

    2017-09-01

    Full Text Available Bundle adjustment with additional parameters is identified as a critical step for precise orthoimage generation and 3D reconstruction of Dunhuang wall paintings. Due to the introduction of self-calibration parameters and quasi-planar constraints, the structure of coefficient matrix of the reduced normal equation is banded-bordered, making the solving process of bundle adjustment complex. In this paper, Conjugate Gradient Bundle Adjustment (CGBA method is deduced by calculus of variations. A preconditioning method based on improved incomplete Cholesky factorization is adopt to reduce the condition number of coefficient matrix, as well as to accelerate the iteration rate of CGBA. Both theoretical analysis and experimental results comparison with conventional method indicate that, the proposed method can effectively conquer the ill-conditioned problem of normal equation and improve the calculation efficiency of bundle adjustment with additional parameters considerably, while maintaining the actual accuracy.

  6. Vertical, Bubbly, Cross-Flow Characteristics over Tube Bundles

    Science.gov (United States)

    Iwaki, C.; Cheong, K. H.; Monji, H.; Matsui, G.

    2005-12-01

    Two-phase flow over tube bundles is commonly observed in shell and tube-type heat exchangers. However, only limited amount of data concerning flow pattern and void fraction exists due to the flow complexity and the difficulties in measurement. The detailed flow structure in tube bundles needs to be understood for reliable and effective design. Therefore, the objective of this study was to clarify the two-phase structure of cross-flow in tube bundles by PIV. Experiments were conducted using two types of models, namely in-line and staggered arrays with a pitch-to-diameter ratio of 1.5. Each test section contains 20 rows of five 15 mm O.D. tubes in each row. The experiment’s data were obtained under very low void fraction (αtube bundles were described in terms of the velocity vector field, turbulence intensity and void fraction.

  7. National Partnership for Maternal Safety: Consensus Bundle on Obstetric Hemorrhage.

    Science.gov (United States)

    Main, Elliott K; Goffman, Dena; Scavone, Barbara M; Low, Lisa Kane; Bingham, Debra; Fontaine, Patricia L; Gorlin, Jed B; Lagrew, David C; Levy, Barbara S

    2015-07-01

    Hemorrhage is the most frequent cause of severe maternal morbidity and preventable maternal mortality and therefore is an ideal topic for the initial national maternity patient safety bundle. These safety bundles outline critical clinical practices that should be implemented in every maternity unit. They are developed by multidisciplinary work groups of the National Partnership for Maternal Safety under the guidance of the Council on Patient Safety in Women's Health Care. The safety bundle is organized into four domains: Readiness, Recognition and Prevention, Response, and Reporting and System Learning. Although the bundle components may be adapted to meet the resources available in individual facilities, standardization within an institution is strongly encouraged. References contain sample resources and "Potential Best Practices" to assist with implementation.

  8. National Partnership for Maternal Safety Consensus Bundle on Obstetric Hemorrhage.

    Science.gov (United States)

    Main, Elliott K; Goffman, Dena; Scavone, Barbara M; Low, Lisa Kane; Bingham, Debra; Fontaine, Patricia L; Gorlin, Jed B; Lagrew, David C; Levy, Barbara S

    2015-01-01

    Hemorrhage is the most frequent cause of severe maternal morbidity and preventable maternal mortality and therefore is an ideal topic for the initial national maternity patient safety bundle. These safety bundles outline critical clinical practices that should be implemented in every maternity unit. They are developed by multidisciplinary work groups of the National Partnership for Maternal Safety under the guidance of the Council on Patient Safety in Women's Health Care. The safety bundle is organized into 4 domains: Readiness, Recognition and Prevention, Response, and Reporting and Systems Learning. Although the bundle components may be adapted to meet the resources available in individual facilities, standardization within an institution is strongly encouraged. References contain sample resources and "Potential Best Practices" to assist with implementation.

  9. Planning and periodization in swimming: An example of a macrocycle for an adapted swimming group

    Directory of Open Access Journals (Sweden)

    A. Querido

    2009-09-01

    Full Text Available The planning of the training process in is commonly recognized as a fundamental aspect for the correct and harmonious development of the capacities and to improve sports results. The aim of this paper was to present an example of a macrocyle of training in a group of adapted swimmers. The group includes 5 swimmers, being 4 male and 1 female: three swimmers with Down syndrome, one swimmer with intellectual disability and one swimmer with autism. The macrocycle of training was subdivided in 23 weeks: 15 belonging to the General Preparation Period, 4 to the Specific Preparation Period, 2 to the Competitive Period, culminating with the Winter National Championships, and 2 to the Transition Period trying. At the Winter National Championships, the most important competition of this macrocycle, these swimmers obtained 7 national titles, 4 national vice-champions titles and 2 third places. These results gave the swimmers an important incentive to keep up the good work.

  10. Planning and periodization in swimming: An example of a macrocycle for an adapted swimming group

    Directory of Open Access Journals (Sweden)

    A. Querido

    2009-01-01

    Full Text Available The planning of the training process in is commonly recognized as a fundamental aspect for the correct and harmonious development of the capacities and to improve sports results. The aim of this paper was to present an example of a macrocyle of training in a group of adapted swimmers. The group includes 5 swimmers, being 4 male and 1 female: three swimmers with Down syndrome, one swimmer with intellectual disability and one swimmer with autism. The macrocycle of training was subdivided in 23 weeks: 15 belonging to the General Preparation Period, 4 to the Specific Preparation Period, 2 to the Competitive Period, culminating with the Winter National Championships, and 2 to the Transition Period trying. At the Winter National Championships, the most important competition of this macrocycle, these swimmers obtained 7 national titles, 4 national vice-champions titles and 2 third places. These results gave the swimmers an important incentive to keep up the good work.

  11. Uranyl-selective PVC membrane electrodes based on some recently synthesized benzo-substituted macrocyclic diamides.

    Science.gov (United States)

    Shamsipur, Mojtaba; Soleymanpour, Ahmad; Akhond, Morteza; Sharghi, Hashem; Massah, Ahmad Reza

    2002-08-23

    Four different recently synthesized macrocyclic diamides were studied to characterize their abilities as uranyl ion carriers in PVC membrane electrodes. The electrodes based on macrocycle 1,18-diaza-3,4;15,16-dibenzo-5,8,11,14,21,24-hexaoxacyclohexaeicosane-2,17-dione resulted in a Nernstian response for UO(2)(2+) ion over wide concentration ranges. The linear concentration range for the polymeric membrane electrode (PME) is 3.0x10(-6)-8.2x10(-3) M with a detection limit of 2.2x10(-6) and that for the coated graphite electrode (CGE) is 5.0x10(-7)-1.5x10(-3) M with a detection limit of 3.5x10(-7) M. The electrodes manifest advantages of low resistance, very fast response and, most importantly, good selectivities relative to a wide variety of other cations.

  12. Ring strain and total syntheses of modified macrocycles of the isoplagiochin type

    Directory of Open Access Journals (Sweden)

    Andreas Speicher

    2009-12-01

    Full Text Available Macrocycles of the bisbibenzyl-type are natural products that are found exclusively in bryophytes (liverworts. The molecular framework of the subtype “isoplagiochin” is of substantial structural interest because of the chirality of the entire molecule, which arises from two biaryl axes in combination with two helical two-carbon units in a cyclic arrangement. From a structural as well as a synthetic point of view we report on the total synthesis of compounds which possess more rigid two-carbon biaryl bridges like stilbene (E or Z or even tolane moieties which were introduced starting with a Sonogashira protocol. The McMurry method proved to be a powerful tool for the cyclization to these considerably ring-strained macrocycles.

  13. Synthesis and anion recognition properties of shape-persistent binaphthyl-containing chiral macrocyclic amides

    Directory of Open Access Journals (Sweden)

    Marco Caricato

    2012-06-01

    Full Text Available We report on the synthesis and characterization of novel shape-persistent, optically active arylamide macrocycles, which can be obtained using a one-pot methodology. Resolved, axially chiral binol scaffolds, which incorporate either methoxy or acetoxy functionalities in the 2,2' positions and carboxylic functionalities in the external 3,3' positions, were used as the source of chirality. Two of these binaphthyls are joined through amidation reactions using rigid diaryl amines of differing shapes, to give homochiral tetraamidic macrocycles. The recognition properties of these supramolecular receptors have been analyzed, and the results indicate a modulation of binding affinities towards dicarboxylate anions, with a drastic change of binding mode depending on the steric and electronic features of the functional groups in the 2,2' positions.

  14. A bambusuril macrocycle that binds anions in water with high affinity and selectivity.

    Science.gov (United States)

    Yawer, Mirza Arfan; Havel, Vaclav; Sindelar, Vladimir

    2015-01-02

    Synthetic receptors that function in water are important for the qualitative and quantitative detection of anions, which may act as pollutants in the environment or play important roles in biological processes. Neutral receptors are particularly appealing because they are often more selective than positively charged receptors; however, their affinity towards anions in pure water is only in range of 1-10(3)  L mol(-1) . The anion-templated synthesis of a water-soluble bambusuril derivative is shown to be an outstanding receptor for various inorganic anions in pure water, with association constants of up to 10(7)  L mol(-1) . Furthermore, the macrocycle discriminates between anions with unprecedented selectivity (up to 500 000-fold). We anticipate that the combination of remarkable affinity and selectivity of this macrocycle will enable the efficient detection and isolation of diverse anions in aqueous solutions, which is not possible with current supramolecular systems.

  15. New Copper and Oxomolybdate Robson-Type Polynuclear Macrocyclic Complexes: Structure, Spectroscopy, and Electrochemical Properties

    Directory of Open Access Journals (Sweden)

    Marcelo Carpes Nunes

    2015-01-01

    Full Text Available The polynuclear complexes [Mo3O8(tidf]·dmso·2H2O (1 and [{Cu2(tidf}2(μ-Mo8O24] (2 (tidf2− is a symmetrical tetraiminodiphenolate Robson-type macrocyclic ligand were prepared from equimolar combinations of [Mg2(tidf](NO32·4H2O, [MoO2Cl2(dmso2] (for 1 and complex 1 and Cu(ClO42·4H2O (for 2 in acetonitrile. Molecular structures of both complexes were determined and showed atypical modes of coordination. A significant observation was the remarkable flexibility of the macrocycle ligand that effectively accommodated the steric demands of metal cations and the packing forces and showed a unique mode of coordination. Spectroscopic (UV-vis and FTIR and redox properties are discussed.

  16. STM visualisation of counterions and the effect of charges on self-assembled monolayers of macrocycles.

    Science.gov (United States)

    Kudernac, Tibor; Shabelina, Natalia; Mamdouh, Wael; Höger, Sigurd; De Feyter, Steven

    2011-01-01

    Despite their importance in self-assembly processes, the influence of charged counterions on the geometry of self-assembled organic monolayers and their direct localisation within the monolayers has been given little attention. Recently, various examples of self-assembled monolayers composed of charged molecules on surfaces have been reported, but no effort has been made to prove the presence of counterions within the monolayer. Here we show that visualisation and exact localisation of counterions within self-assembled monolayers can be achieved with scanning tunnelling microscopy (STM). The presence of charges on the studied shape-persistent macrocycles is shown to have a profound effect on the self-assembly process at the liquid-solid interface. Furthermore, preferential adsorption was observed for the uncharged analogue of the macrocycle on a surface.

  17. A Novel Cobalt(Ⅲ) Complex with Macrocyclic Triamine Ligand for High Capacity Hydrogen Adsorption

    Institute of Scientific and Technical Information of China (English)

    ZHU Hai-Yan; GUO Hui; LI Sai

    2012-01-01

    The coordination complex of Co(Ⅲ) based on a macrocyclic triamine ligand 1,4-diacetate-1,4,7-triazacyclodecane (L) has been synthesized and characterized. The metal cation is bonded with three nitrogen atoms and two oxygen atoms of L and one chloride ion to form a distorted octahedral geometry. This complex coordinated with macrocyclic ligand possesses large pore volume that will be contributed to observe high H2 adsorption. With respect to the first-principles electronic structure calculations, the feasibility to store hydrogen in the complex is explored. Indeed, the complex has shown a very high total H2 adsorption of 7.2 wt% (wt% = (weight of adsorbed H2)/(weight of host material)), with a binding energy of 0.03 eV/H2

  18. A comprehensive electronic structure description of a biscyanotetraazacobalt(III) macrocyclic complex.

    Science.gov (United States)

    Ishiruji, Fabiana Hitomi Ono; Nunes, Fábio Souza

    2007-09-01

    Molecular modeling and a detailed spectroscopic characterization of the macrocyclic complex [Co(meso)(CN)(2)](+) (meso = 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane) is herein presented. Structural, electronic and vibrational features are discussed and assignments were proposed on the basis of semi-empirical (molecular mechanics (MM+), ZINDO/S and PM3) quantum-mechanics calculations. The energy and the composition of the molecular orbitals of the complex were calculated and a quantitative diagram was constructed. The simulated UV-vis spectrum exhibited a reasonably good accordance with the experimental one and fully assignments of seven bands were made. An optimized configuration of the complex showed a strong cobalt-cyanide axial bond in agreement with the major contribution of the cyanide to the composition of the molecular orbitals in contrast to a discrete participation of the macrocyclic meso to the ground state of the complex.

  19. mRNA display: from basic principles to macrocycle drug discovery.

    Science.gov (United States)

    Josephson, Kristopher; Ricardo, Alonso; Szostak, Jack W

    2014-04-01

    We describe a new discovery technology that uses mRNA-display to rapidly synthesize and screen macrocyclic peptide libraries to explore a valuable region of chemical space typified by natural products. This technology allows high-affinity peptidic macrocycles containing modified backbones and unnatural side chains to be readily selected based on target binding. Success stories covering the first examples of these libraries suggest that they could be used for the discovery of intracellular protein-protein interaction inhibitors, highly selective enzyme inhibitors or synthetic replacements for monoclonal antibodies. The review concludes with a look to the future regarding how this technology might be improved with respect to library design for cell permeability and bioavailability.

  20. Biodegradable polyester-based eco-composites containing hemp fibers modified with macrocyclic oligomers

    Science.gov (United States)

    Conzatti, Lucia; Utzeri, Roberto; Hodge, Philip; Stagnaro, Paola

    2016-05-01

    An original compatibilizing pathway for hemp fibers/poly(1,4-butylene adipate-co-terephtalate) (PBAT) eco-composites was explored exploiting the capability of macrocyclic oligomers (MCOs), obtained by cyclodepolymerization (CDP) of PBAT at high dilution, of being re-converted into linear chains by entropically-driven ring-opening polymerization (ED-ROP) that occurs simply heating the MCOS in the bulk. CDP reaction of PBAT was carried out varying solvent, catalyst and reaction time. Selected MCOs were used to adjust the conditions of the ED-ROP reaction. The best experimental conditions were then adopted to modify hemp fibers. Eco-composites based on PBAT and hemp fibers as obtained or modified with PBAT macrocyclics or oligomers were prepared by different process strategies. The best fiber-PBAT compatibility was observed when the fibers were modified with PBAT oligomers before incorporation in the polyester matrix.

  1. Template synthesis of macrocyclic complexes and their spectroscopic and antibacterial studies.

    Science.gov (United States)

    Singh, D P; Grover, Vidhi; Kumar, Ramesh; Jain, Kiran

    2010-06-01

    A new series of macrocyclic complexes of type [M(TML)X]X(2), where M = Cr(III), Fe(III), TML is tetradentate macrocyclic ligand, and X = Cl(-), NO(3)(-), CH(3)COO(-), have been synthesized by condensation of isatin and ethylenediamine in the presence of metal salt. The complexes were synthesized by both conventional and microwave methods. The complexes have been characterized with the help of elemental analysis, conductance measurement, magnetic measurement, and infrared, far infrared, and electronic spectral studies. Molar conductance values indicate them to be 1:2 electrolytes. Electronic spectra along with magnetic moments suggest five-coordinate square pyramidal geometry for these complexes. The complexes were also tested for their in vitro antibacterial activity. Some of the complexes showed satisfactory antibacterial activitiy.

  2. The Click Reaction as an Efficient Tool for the Construction of Macrocyclic Structures

    Directory of Open Access Journals (Sweden)

    Dario Pasini

    2013-08-01

    Full Text Available The Cu(I-catalyzed azide-alkyne cycloaddition (CuAAC, known as the click reaction is an established tool used for the construction of complex molecular architectures. Given its efficiency it has been widely applied for bioconjugation, polymer and dendrimer synthesis. More recently, this reaction has been utilized for the efficient formation of rigid or shape-persistent, preorganized macrocyclic species. This strategy also allows the installment of useful functionalities, in the form of polar and function-rich 1,2,3-triazole moieties, directly embedded in the macrocyclic structures. This review analyzes the state of the art in this context, and provides some elements of perspective for future applications.

  3. Performance-based bundled payments: potential benefits and burdens.

    Science.gov (United States)

    Satin, David J; Miles, Justin

    2009-10-01

    Performance-based bundled payments have emerged as the most recent iteration of pay for performance. These are programs in which providers are paid a single fee for a set of evidenced-based services related to a diagnosis. The payments are typically linked to outcomes as well as other quality measures. This paper reviews two prominent bundled payment programs--PROMETHEUS and ProvenCare--and discusses the potential pitfalls of these approaches.

  4. Identity-Based Cryptosystems for Enhanced Deployment of OSGi Bundles

    OpenAIRE

    Parrend, Pierre; Galice, Samuel; Frénot, Stéphane; Ubéda, Stéphane

    2007-01-01

    International audience; The OSGi platform is designed to make Java soft- ware extensible at runtime. This undeniably presents a great interest in several domains like embedded plat- forms or enterprise application servers. However, se- curing the deployment of the OSGi components, or bundles, proves to be a major challenge. The current approach consists in digitally signing the bundles and certifying the signature through a Public Key Infras- tructure. We propose to replace this technology wi...

  5. Codimension-Three Bundle Singularities in F-Theory

    CERN Document Server

    Candelas, Philip; Florea, B; Morrison, Douglas Robert Ogston; Rajesh, G; Candelas, Philip; Diaconescu, Duiliu-Emanuel; Florea, Bogdan; Morrison, David R.; Rajesh, Govindan

    2002-01-01

    We study new nonperturbative phenomena in N=1 heterotic string vacua corresponding to pointlike bundle singularities in codimension three. These degenerations result in new four-dimensional infrared physics characterized by light solitonic states whose origin is explained in the dual F-theory model. We also show that such phenomena appear generically in $E_7 \\to E_6$ Higgsing and describe in detail the corresponding bundle transition.

  6. Generalized holomorphic bundles and the B-field action

    CERN Document Server

    Hitchin, Nigel

    2010-01-01

    On a generalized complex manifold there is an associated definition of a generalized holomorphic bundle, introduced by Gualtieri. This notion in the case of an ordinary complex structure yields an object which we call a co-Higgs bundle and we consider the B-field action of a closed form of type (1,1), both local and global. The effect makes contact with both Nahm's equations and holomorphic gerbes.

  7. Generalized holomorphic bundles and the B-field action

    Science.gov (United States)

    Hitchin, Nigel

    2011-01-01

    On a generalized complex manifold, there is an associated definition of a generalized holomorphic bundle, introduced by Gualtieri. In the case of an ordinary complex structure, this notion yields an object which we call a co-Higgs bundle, and we consider the B-field action of a closed form of type (1,1), both local and global. The effect makes contact with both Nahm's equations and holomorphic gerbes.

  8. Simplified modeling of EM field coupling to complex cable bundles

    OpenAIRE

    Schetelig, B.; J. Keghie; Kanyou Nana, R.; Fichte, L.-O.; S. Potthast; Dickmann, S.

    2010-01-01

    In this contribution, the procedure "Equivalent Cable Bundle Method" is used for the simplification of large cable bundles, and it is extended to the application on differential signal lines. The main focus is on the reduction of twisted-pair cables. Furthermore, the process presented here allows to take into account cables with wires that are situated quite close to each other. The procedure is based on a new approach to calculate the geometry of the simplified cable and us...

  9. Dunkl Operators as Covariant Derivatives in a Quantum Principal Bundle

    OpenAIRE

    Micho Đurđevich; Stephen Bruce Sontz

    2011-01-01

    A quantum principal bundle is constructed for every Coxeter group acting on a finite-dimensional Euclidean space $E$, and then a connection is also defined on this bundle. The covariant derivatives associated to this connection are the Dunkl operators, originally introduced as part of a program to generalize harmonic analysis in Euclidean spaces. This gives us a new, geometric way of viewing the Dunkl operators. In particular, we present a new proof of the commutativity of these operators amo...

  10. Special physical preparation of skilled wrestlers during a macrocycle in the conditions of higher educational establishment.

    Directory of Open Access Journals (Sweden)

    Ogar' G.O.

    2010-12-01

    Full Text Available It is developed and experimentally grounded efficiency and methods of improvement of the special physical preparedness of skilled fighters. It is certain that a method parts on a few stages of preparation of training macrocycle and optimized for sportsmen which parallel study in higher educational establishment. It is set that the educational training process of skilled fighters must take into account the specific of organization of educational process of educational establishment and answer the calendar of competitions on a CY.

  11. Lead Diversification through a Prins-Driven Macrocyclization Strategy: Application to C13-Diversified Bryostatin Analogues.

    Science.gov (United States)

    Wender, Paul A; Billingsley, Kelvin L

    2013-01-01

    The design, synthesis, and biological evaluation of a novel class of C13-diversified bryostatin analogues are described. An innovative and general strategy based on a Prins macrocyclization-nucleophilic trapping cascade was used to achieve late-stage diversification. In vitro analysis of selected library members revealed that modification at the C13 position of the bryostatin scaffold can be used as a diversification handle to regulate biological activity.

  12. Ligand and Metalloligand Design for Macrocycles, Multimetallic Arrays, Coordination Polymers and Assemblies

    OpenAIRE

    E. C. Constable; Housecroft, C. E.

    2016-01-01

    This overview of ligand design focuses on three areas: (i) principles of ligand binding, the formation of complexes, and popular strategies for ligand synthesis; (ii) ligand design in macrocyclic complexes, coordination polymers and networks and metallopolygons, and assembly strategies based upon the use of metalloligand building blocks; (iii) ligand design for the extraction and transport of metals. This area of coordination chemistry is too large to permit a comprehensive survey in the spac...

  13. Syntheses of Macrocyclic Amides from L-Amino Acid Esters by RCM

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A series of succinate-derived macrocyclic amides( 1 ) was synthesized via ring-closing metathesis (RCM) as the key step. The substrate included 12 to 15 members. The metathesis precursors were obtained from the amide coupling of tert-butyl 3-carboxyhex-5-enoate(2) with numerous side-chain alkenylated amino acid esters of general type(3)derived from L-lysine and L-ornithine.

  14. Macrocyclic hexaoxazoles: Influence of aminoalkyl substituents on RNA and DNA G-quadruplex stabilization and cytotoxicity.

    Science.gov (United States)

    Satyanarayana, Mavurapu; Kim, Young-Ah; Rzuczek, Suzanne G; Pilch, Daniel S; Liu, Angela A; Liu, Leroy F; Rice, Joseph E; LaVoie, Edmond J

    2010-05-15

    A series of 24-membered macrocyclic hexaoxazoles containing one or two aminoalkyl substituents was synthesized and evaluated for cytotoxicity and for their ability to selectively stabilize G-quadruplex DNA and RNA. The most cytotoxic analog 4a, with IC(50) values of 25 and 130 nM using KB3-1 and RPMI 8402 cells, is efficacious in vivo in athymic nude mice with a human tumor xenograft from the breast cancer cell line MDA-MB-435.

  15. Synthesis, spectral and extended spectrum beta-lactamase studies of transition metal tetraaza macrocyclic complexes.

    Science.gov (United States)

    Kumar, Dinesh; Sharma, Nutan; Nair, Manjula

    2017-01-18

    Urinary tract infections commonly occur in humans due to microbial pathogens invading the urinary tract, which can bring about a range of clinical symptoms and potentially fatal sequelae. The present study is aimed at addressing the development of a new antimicrobial agent against extended spectrum beta lactamase (ESBL) producing E. coli bacteria. We have synthesised some biologically potent (NNNN) donor macrocycles (L 1  = dibenzo[f,n]dipyrido[3,4-b:4',3'-j][1,4,9,12]tetraazacyclohexadecine-6,11,18,23(5H,12H, 7H, 24H)-tetraone, and L 2  = 6,12,19,25-tetraoxo-4,6,11,12,16,18,23,24-octahydrotetrabenzo [b,g,k,p][1,5,10,14]tetra azacyclooctadecine-2,13-dicarboxylic acid) and their Ti and Zr metal complexes in alcoholic media using microwave protocol. Macrocyclic ligands were synthesised by incorporating of 3,5-diaminobenzoic acid, phthalic acid and 3,4-diaminopyridine in 1:1:1 molar ratio. The macrocyclic ligands and their metal complexes have been characterised by elemental analysis, conductance measurement, magnetic measurement and their structure configurations have been determined by various spectroscopic (FTIR, (1)H/(13)C NMR, UV-Vis, LC-MS mass, XRD and TGA) techniques. [ZrL2Cl2]Cl2 metal complex shows excellent antibacterial activity against ESBLs. A zone of inhibition and minimum inhibitory concentration was determined by McFarland and the dilution method, respectively. The spectral studies confirm the binding sites of the nitrogen atom of the macrocycles. An octahedral geometry has been assigned to the metal complexes based on the findings.

  16. BiSet: Semantic Edge Bundling with Biclusters for Sensemaking.

    Science.gov (United States)

    Sun, Maoyuan; Mi, Peng; North, Chris; Ramakrishnan, Naren

    2016-01-01

    Identifying coordinated relationships is an important task in data analytics. For example, an intelligence analyst might want to discover three suspicious people who all visited the same four cities. Existing techniques that display individual relationships, such as between lists of entities, require repetitious manual selection and significant mental aggregation in cluttered visualizations to find coordinated relationships. In this paper, we present BiSet, a visual analytics technique to support interactive exploration of coordinated relationships. In BiSet, we model coordinated relationships as biclusters and algorithmically mine them from a dataset. Then, we visualize the biclusters in context as bundled edges between sets of related entities. Thus, bundles enable analysts to infer task-oriented semantic insights about potentially coordinated activities. We make bundles as first class objects and add a new layer, "in-between", to contain these bundle objects. Based on this, bundles serve to organize entities represented in lists and visually reveal their membership. Users can interact with edge bundles to organize related entities, and vice versa, for sensemaking purposes. With a usage scenario, we demonstrate how BiSet supports the exploration of coordinated relationships in text analytics.

  17. Experimental investigation of the coolability of blocked hexagonal bundles

    Energy Technology Data Exchange (ETDEWEB)

    Hózer, Zoltán, E-mail: zoltan.hozer@energia.mta.hu; Nagy, Imre; Kunstár, Mihály; Szabó, Péter; Vér, Nóra; Farkas, Róbert; Trosztel, István; Vimi, András

    2017-06-15

    Highlights: • Experiments were performed with electrically heated hexagonal fuel bundles. • Coolability of ballooned VVER-440 type bundle was confirmed up to high blockage rate. • Pellet relocation effect causes delay in the cool-down of the bundle. • The bypass line does not prevent the reflood of ballooned fuel rods. - Abstract: The CODEX-COOL experimental series was carried out in order to evaluate the effect of ballooning and pellet relocation in hexagonal bundles on the coolability of fuel rods after a LOCA event. The effects of blockage geometry, coolant flowrate, initial temperature and axial profile were investigated. The experimental results confirmed that a VVER bundle up to 80% blockage rate remains coolable after a LOCA event under design basis conditions. The ballooned section creates some obstacles for the cooling water during reflood of the bundle, but this effect causes only a short delay in the cooling down of the hot fuel rods. The accumulation of fuel pellet debris in the ballooned volume results in a local power peak, which leads to further slowing down of quench front.

  18. Oscillation of carbon molecules inside carbon nanotube bundles

    Science.gov (United States)

    Thamwattana, Ngamta; Cox, Barry J.; Hill, James M.

    2009-04-01

    In this paper, we investigate the mechanics of a nanoscaled gigahertz oscillator comprising a carbon molecule oscillating within the centre of a uniform concentric ring or bundle of carbon nanotubes. Two kinds of oscillating molecules are considered, which are a carbon nanotube and a C60 fullerene. Using the Lennard-Jones potential and the continuum approach, we obtain a relation between the bundle radius and the radii of the nanotubes forming the bundle, as well as the optimum bundle size which gives rise to the maximum oscillatory frequency for both the nanotube-bundle and the C60-bundle oscillators. While previous studies in this area have been undertaken through molecular dynamics simulations, this paper emphasizes the use of applied mathematical modelling techniques, which provides considerable insight into the underlying mechanisms of the nanoscaled oscillators. The paper presents a synopsis of the major results derived in detail by the present authors (Cox et al 2007 Proc. R. Soc. A 464 691-710 and Cox et al 2007 J. Phys. A: Math. Theor. 40 13197-208).

  19. Alternating 2,6-/3,5-substituted pyridine-acetylene macrocycles: π-stacking self-assemblies enhanced by intermolecular dipole-dipole interaction.

    Science.gov (United States)

    Abe, Hajime; Ohtani, Kohei; Suzuki, Daiki; Chida, Yusuke; Shimada, Yuta; Matsumoto, Shinya; Inouye, Masahiko

    2014-02-07

    Macrocyclic compounds consisting of three 2,6-pyridylene and three 3,5-pyridylene units linked by acetylene bonds were synthesized by a Sonogashira reaction. The X-ray structures showed π-stacked pairs of two macrocycles, in which a 2,6-pyridylene unit of the one molecule overlaps a 3,5-pyridylene of the other molecule because of dipole-dipole interaction. Atomic force microscope (AFM) measurements revealed fibril structures indicating the stacking of the rigid planar macrocycles. Hydrogen-bonding ability of the macrocyclic inside was demonstrated by the addition of octyl β-D-glucopyranoside.

  20. Macrocycle peptides delineate locked-open inhibition mechanism for microorganism phosphoglycerate mutases

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Hao; Dranchak, Patricia; Li, Zhiru; MacArthur, Ryan; Munson, Matthew S.; Mehzabeen, Nurjahan; Baird, Nathan J.; Battalie, Kevin P.; Ross, David; Lovell, Scott; Carlow, Clotilde K.S.; Suga, Hiroaki; Inglese, James (U of Tokyo); (NEB); (Kansas); (NIH); (NIST); (HHMI)

    2017-04-03

    Glycolytic interconversion of phosphoglycerate isomers is catalysed in numerous pathogenic microorganisms by a cofactor-independent mutase (iPGM) structurally distinct from the mammalian cofactor-dependent (dPGM) isozyme. The iPGM active site dynamically assembles through substrate-triggered movement of phosphatase and transferase domains creating a solvent inaccessible cavity. Here we identify alternate ligand binding regions using nematode iPGM to select and enrich lariat-like ligands from an mRNA-display macrocyclic peptide library containing >1012 members. Functional analysis of the ligands, named ipglycermides, demonstrates sub-nanomolar inhibition of iPGM with complete selectivity over dPGM. The crystal structure of an iPGM macrocyclic peptide complex illuminated an allosteric, locked-open inhibition mechanism placing the cyclic peptide at the bi-domain interface. This binding mode aligns the pendant lariat cysteine thiolate for coordination with the iPGM transition metal ion cluster. The extended charged, hydrophilic binding surface interaction rationalizes the persistent challenges these enzymes have presented to small-molecule screening efforts highlighting the important roles of macrocyclic peptides in expanding chemical diversity for ligand discovery.

  1. Redox-Active Tetraruthenium Macrocycles Built from 1,4-Divinylphenylene-Bridged Diruthenium Complexes.

    Science.gov (United States)

    Scheerer, Stefan; Linseis, Michael; Wuttke, Evelyn; Weickert, Sabrina; Drescher, Malte; Tröppner, Oliver; Ivanović-Burmazović, Ivana; Irmler, Andreas; Pauly, Fabian; Winter, Rainer F

    2016-07-01

    Metallamacrocylic tetraruthenium complexes were generated by treatment of 1,4-divinylphenylene-bridged diruthenium complexes with functionalized 1,3-benzene dicarboxylic acids and characterized by HR ESI-MS and multinuclear NMR spectroscopy. Every divinylphenylene diruthenium subunit is oxidized in two consecutive one-electron steps with half-wave potential splittings in the range of 250 to 330 mV. Additional, smaller redox-splittings between the +/2+ and 0/+ and the 3+/4+ and 2+/3+ redox processes, corresponding to the first and the second oxidations of every divinylphenylene diruthenium entity, are due to electrostatic effects. The lack of electronic coupling through bond or through space is explained by the nodal properties of the relevant molecular orbitals and the lateral side-by-side arrangement of the divinylphenylene linkers. The polyelectrochromic behavior of the divinylphenylene diruthenium precursors is retained and even amplified in these metallamacrocyclic structures. EPR studies down to T=4 K indicate that the dications 1-H(2+) and 1-OBu(2+) are paramagnetic. The dications and the tetracation of macrocycle 3-H display intense (dications) or weak (3-H(4+) ) EPR signals. Quantum chemical calculations indicate that the four most stable conformers of the macrocycles are largely devoid of strain. Bond parameters, energies as well as charge and spin density distributions of model macrocycle 5-H(Me) were calculated for the different charge and spin states.

  2. History of avermectin and ivermectin, with notes on the history of other macrocyclic lactone antiparasitic agents.

    Science.gov (United States)

    Campbell, William C

    2012-05-01

    The macrocyclic lactones enjoy a position of prominence in the control of parasites, and their history may be of interest, and even of use, in an age in which the search for chemotherapeutic agents has been transformed by modern technology. Much of their history has been recorded piecemeal in a wide variety of publications. The present review provides additional detail, and offers a personal perspective on the history of ivermectin and related avermectins. Brief notes are included on the subsequent development of other macrocyclic lactones. Milbemycin preceded the avermectins as a macrocyclic lactone of agricultural importance, but was used for a different purpose. Development of the avermectins arose from the isolation, in the laboratories of the Kitasato Institute, of a novel soil-dwelling bacterium and its transmittal (in 1974) to the laboratories of Merck & Co., Inc. There it was found (in 1975) to produce a potent anthelmintic substance, which was then identified and transmuted by interdisciplinary research into an antiparasitic product. Initially the focus was on its applicability to veterinary science and animal husbandry; and after developmental research by many scientific teams, the product was introduced commercially (in 1981) for the control of endoparasitic nematodes and ectoparasitic arthropods in livestock. Subsequently, special applications in human medicine were developed, and were successfully implemented in partnership with World Health Organization and several non-governmental organizations (NGOs).

  3. Heartworms, macrocyclic lactones, and the specter of resistance to prevention in the United States

    Directory of Open Access Journals (Sweden)

    Bowman Dwight D

    2012-07-01

    Full Text Available Abstract In order to provide a background to current concerns relative to the possible resistance of heartworms to macrocyclic lactones, this review summarizes various studies in which lack of efficacies (LOEs have been observed in dogs on macrocyclic lactone preventives relative to the United States of America. Some of these studies have been published in the peer-reviewed literature, others have appeared in various reports to the Center for Veterinary Medicine (CVM of the Food and Drug Administration (FDA of the USA as New Animal Drug Application (NADA summaries, and one appeared as a letter to US veterinarians. This review also discusses reports relating to the potential problem of heartworm resistance in microfilariae and third-stage larvae, as well as molecular markers associated with resistance to macrocyclic lactones within Dirofilaria immitis. As more work is being done in this area of great concern relative to the protection of dogs from infection using this class of preventives, it seems timely to summarize what is known about heartworms, their potential resistance to treatment, and the means of selecting for resistance genes in populations of this helminth in the laboratory and in the field.

  4. Increasing AIP Macrocycle Size Reveals Key Features of agr Activation in Staphylococcus aureus.

    Science.gov (United States)

    Johnson, Jeffrey G; Wang, Boyuan; Debelouchina, Galia T; Novick, Richard P; Muir, Tom W

    2015-05-04

    The agr locus in the commensal human pathogen, Staphylococcus aureus, is a two-promoter regulon with allelic variability that produces a quorum-sensing circuit involved in regulating virulence within the bacterium. Secretion of unique autoinducing peptides (AIPs) and detection of their concentrations by AgrC, a transmembrane receptor histidine kinase, coordinates local bacterial population density with global changes in gene expression. The finding that staphylococcal virulence can be inhibited through antagonism of this quorum-sensing pathway has fueled tremendous interest in understanding the structure-activity relationships underlying the AIP-AgrC interaction. The defining structural feature of the AIP is a 16-membered, thiolactone-containing macrocycle. Surprisingly, the importance of ring size on agr activation or inhibition has not been explored. In this study, we address this deficiency through the synthesis and functional analysis of AIP analogues featuring enlarged and reduced macrocycles. Notably, this study is the first to interrogate AIP function by using both established cell-based reporter gene assays and newly developed in vitro AgrC-I binding and autophosphorylation activity assays. Based on our data, we present a model for robust agr activation involving a cooperative, three-points-of-contact interaction between the AIP macrocycle and AgrC.

  5. Dethreading of Tetraalkylsuccinamide-Based [2]Rotaxanes for Preparing Benzylic Amide Macrocycles.

    Science.gov (United States)

    Martinez-Cuezva, Alberto; Rodrigues, Leticia V; Navarro, Cristian; Carro-Guillen, Fernando; Buriol, Lilian; Frizzo, Clarissa P; Martins, Marcos A P; Alajarin, Mateo; Berna, Jose

    2015-10-16

    The dethreading of a series of succinamide-based [2]rotaxanes bearing benzylic amide macrocycles is reported herein. These transformations proceeded quantitatively either under flash vacuum pyrolysis, conventional heating, or microwave irradiation. Studying the size complementarity of the stoppers at the ends of the thread and the cavity of the macrocycle allowed us to set up the best substituents for implementing the extrusion of the thread from the interlocked precursors. A variety of (1)H NMR kinetic experiments were carried out in order to evaluate the rate constants of the dethreading process, the half-life times of the rotaxanes, and the influence of temperature and solvents on these processes. The use of dibutylamino groups as stoppers yielded the rotaxane precursor in a reasonable yield and allowed the quantitative deslipping of the rotaxane. The overall process, including the rotaxane formation and its further dethreading, has been exploited for preparing benzylic amide macrocycles enhancing, in most cases, the results of the classical (2 + 2) condensation and other reported stepwise syntheses. The kinetics of the dethreading process is fairly sensitive to the electronic effects of the substituents on the isophthalamide unit or to the electronic nature of the pyridine rings through a conformational equilibrium expanding or contracting the cavity of the interlocked precursor.

  6. Combustor having mixing tube bundle with baffle arrangement for directing fuel

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, Michael John; McConnaughhay, Johnie Franklin

    2016-08-23

    A combustor includes a tube bundle that extends radially across at least a portion of the combustor. The tube bundle includes an upstream surface axially separated from a downstream surface, and a plurality of tubes extend from the upstream surface through the downstream surface to provide fluid communication through the tube bundle. A barrier extends radially inside the tube bundle between the upstream and downstream surfaces, and a baffle extends axially inside the tube bundle between the upstream surface and the barrier.

  7. Incorporation of trinuclear lanthanide(III) hydroxo bridged clusters in macrocyclic frameworks.

    Science.gov (United States)

    Kobyłka, Michał J; Ślepokura, Katarzyna; Acebrón Rodicio, Maria; Paluch, Marta; Lisowski, Jerzy

    2013-11-18

    A cluster of lanthanide(III) or yttrium(III) ions, Ln3(μ3-OH)2, (Ln(III) = Nd(III), Sm(III), Eu(III), Gd(III), Tb(III), Dy(III), Yb(III), or Y(III)) can be bound in the center of a chiral macrocyclic amines H3L1(R), H3L1(S), and H3L2(S) obtained in a reduction of a 3 + 3 condensation product of (1R,2R)- or (1S,2S)-1,2-diaminocyclohexane and 2,6-diformyl-4-methylphenol or 2,6-diformyl-4-tertbutylphenol. X-ray crystal structures of the Nd(III), Sm(III), Gd(III), Dy(III), and Y(III) complexes reveal trinuclear complexes with Ln(III) ions bridged by the phenolate oxygen atoms of the macrocycle as well as by μ3-hydroxo bridges. In the case of the Nd(III) ion, another complex form can be obtained, whose X-ray crystal structure reveals two trinuclear macrocyclic units additionally bridged by hydroxide anions, corresponding to a [Ln3(μ3-OH)]2(μ2-OH)2 cluster encapsulated by two macrocycles. The formation of trinuclear complexes is confirmed additionally by (1)H NMR, electrospray ionization mass spectrometry (ESI MS), and elemental analyses. Titrations of free macrocycles with Sm(III) or Y(III) salts and KOH also indicate that a trinuclear complex is formed in solution. On the other hand, analogous titrations with La(III) salt indicate that this kind of complex is not formed even with the excess of La(III) salt. The magnetic data for the trinuclear Gd(III) indicate weak antiferromagnetic coupling (J = -0.17 cm(-1)) between the Gd(III) ions. For the trinuclear Dy(III) and Tb(III) complexes the χ(M)T vs T plots indicate a more complicated dependence, resulting from the combination of thermal depopulation of mJ sublevels, magnetic anisotropy, and possibly weak antiferromagnetic and ferromagnetic interactions.

  8. Enantiomeric self-recognition in homo- and heterodinuclear macrocyclic lanthanide(III) complexes.

    Science.gov (United States)

    Lisowski, Jerzy

    2011-06-20

    The controlled formation of lanthanide(III) dinuclear μ-hydroxo-bridged [Ln(2)L(2)(μ-OH)(2)X(2)](n+) complexes (where X = H(2)O, NO(3)(-), or Cl(-)) of the enantiopure chiral macrocycle L is reported. The (1)H and (13)C NMR resonances of these complexes have been assigned on the basis of COSY, NOESY, TOCSY, and HMQC spectra. The observed NOE connectivities confirm that the dimeric solid-state structure is retained in solution. The enantiomeric nature of the obtained chiral complexes and binding of hydroxide anions are reflected in their CD spectra. The formation of the dimeric complexes is accompanied by a complete enantiomeric self-recognition of the chiral macrocyclic units. The reaction of NaOH with a mixture of two different mononuclear lanthanide(III) complexes, [Ln(1)L](3+) and [Ln(2)L](3+), results in formation of the heterodinuclear [Ln(1)Ln(2)L(2)(μ-OH)(2)X(2)](n+) complexes as well as the corresponding homodinuclear complexes. The formation of the heterodinuclear complex is directly confirmed by the NOESY spectra of [EuLuL(2)(μ-OH)(2)(H(2)O)(2)](4+), which reveal close contacts between the macrocyclic unit containing the Eu(III) ion and the macrocyclic unit containing the Lu(III) ion. While the relative amounts of homo- and heterodinuclear complexes are statistical for the two lanthanide(III) ions of similar radii, a clear preference for the formation of heterodinuclear species is observed when the two mononuclear complexes contain lanthanide(III) ions of markedly different sizes, e.g., La(III) and Yb(III). The formation of heterodinuclear complexes is accompanied by the self-sorting of the chiral macrocyclic units based on their chirality. The reactions of NaOH with a pair of homochiral or racemic mononuclear complexes, [Ln(1)L(RRRR)](3+)/[Ln(2)L(RRRR)](3+), [Ln(1)L(SSSS)](3+)/[Ln(2)L(SSSS)](3+), or [Ln(1)L(rac)](3+)/[Ln(2)L(rac)](3+), results in mixtures of homochiral, homodinuclear and homochiral, heterodinuclear complexes. On the contrary, no

  9. Novel Potent Hepatitis C Virus NS3 Serine Protease Inhibitors Derived from Proline-Based Macrocycles

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Kevin X.; Njoroge, F. George; Arasappan, Ashok; Venkatraman, Srikanth; Vibulbhan, Bancha; Yang, Weiying; Parekh, Tejal N.; Pichardo, John; Prongay, Andrew; Cheng, Kuo-Chi; Butkiewicz, Nancy; Yao, Nanhua; Madison, Vincent; Girijavallabhan, Viyyoor (SPRI)

    2008-06-30

    The hepatitis C virus (HCV) NS3 protease is essential for viral replication. It has been a target of choice for intensive drug discovery research. On the basis of an active pentapeptide inhibitor, 1, we envisioned that macrocyclization from the P2 proline to P3 capping could enhance binding to the backbone Ala156 residue and the S4 pocket. Thus, a number of P2 proline-based macrocyclic {alpha}-ketoamide inhibitors were prepared and investigated in an HCV NS3 serine protease continuous assay (K*{sub i}). The biological activity varied substantially depending on factors such as the ring size, number of amino acid residues, number of methyl substituents, type of heteroatom in the linker, P3 residue, and configuration at the proline C-4 center. The pentapeptide inhibitors were very potent, with the C-terminal acids and amides being the most active ones (24, K*{sub i} = 8 nM). The tetrapeptides and tripeptides were less potent. Sixteen- and seventeen-membered macrocyclic compounds were equally potent, while fifteen-membered analogues were slightly less active. gem-Dimethyl substituents at the linker improved the potency of all inhibitors (the best compound was 45, K*{sub i} = 6 nM). The combination of tert-leucine at P3 and dimethyl substituents at the linker in compound 47 realized a selectivity of 307 against human neutrophil elastase. Compound 45 had an IC{sub 50} of 130 nM in a cellular replicon assay, while IC{sub 50} for 24 was 400 nM. Several compounds had excellent subcutaneous AUC and bioavailability in rats. Although tripeptide compound 40 was 97% orally bioavailable, larger pentapeptides generally had low oral bioavailability. The X-ray crystal structure of compounds 24 and 45 bound to the protease demonstrated the close interaction of the macrocycle with the Ala156 methyl group and S4 pocket. The strategy of macrocyclization has been proved to be successful in improving potency (>20-fold greater than that of 1) and in structural depeptization.

  10. Histones bundle F-actin filaments and affect actin structure.

    Science.gov (United States)

    Blotnick, Edna; Sol, Asaf; Muhlrad, Andras

    2017-01-01

    Histones are small polycationic proteins complexed with DNA located in the cell nucleus. Upon apoptosis they are secreted from the cells and react with extracellular polyanionic compounds. Actin which is a polyanionic protein, is also secreted from necrotic cells and interacts with histones. We showed that both histone mixture (histone type III) and the recombinant H2A histone bundles F-actin, increases the viscosity of the F-actin containing solution and polymerizes G-actin. The histone-actin bundles are relatively insensitive to increase of ionic strength, unlike other polycation, histatin, lysozyme, spermine and LL-37 induced F-actin bundles. The histone-actin bundles dissociate completely only in the presence of 300-400 mM NaCl. DNA, which competes with F-actin for histones, disassembles histone induced actin bundles. DNase1, which depolymerizes F- to G-actin, actively unbundles the H2A histone induced but slightly affects the histone mixture induced actin bundles. Cofilin decreases the amount of F-actin sedimented by low speed centrifugation, increases light scattering and viscosity of F-actin-histone mixture containing solutions and forms star like superstructures by copolymerizing G-actin with H2A histone. The results indicate that histones are tightly attached to F-actin by strong electrostatic and hydrophobic forces. Since both histones and F-actin are present in the sputum of patients with cystic fibrosis, therefore, the formation of the stable histone-actin bundles can contribute to the pathology of this disease by increasing the viscosity of the sputum. The actin-histone interaction in the nucleus might affect gene expression.

  11. External Verification of the Bundle Adjustment in Photogrammetric Software Using the Damped Bundle Adjustment Toolbox

    Science.gov (United States)

    Börlin, Niclas; Grussenmeyer, Pierre

    2016-06-01

    The aim of this paper is to investigate whether the Matlab-based Damped Bundle Adjustment Toolbox (DBAT) can be used to provide independent verification of the BA computation of two popular software—PhotoModeler (PM) and PhotoScan (PS). For frame camera data sets with lens distortion, DBAT is able to reprocess and replicate subsets of PM results with high accuracy. For lens-distortion-free data sets, DBAT can furthermore provide comparative results between PM and PS. Data sets for the discussed projects are available from the authors. The use of an external verification tool such as DBAT will enable users to get an independent verification of the computations of their software. In addition, DBAT can provide computation of quality parameters such as estimated standard deviations, correlation between parameters, etc., something that should be part of best practice for any photogrammetric software. Finally, as the code is free and open-source, users can add computations of their own.

  12. An in vitro biomechanical comparison of anterior cruciate ligament reconstruction: single bundle versus anatomical double bundle techniques

    Directory of Open Access Journals (Sweden)

    Sandra Umeda Sasaki

    2008-01-01

    Full Text Available INTRODUCTION: Anterior cruciate ligament ruptures are frequent, especially in sports. Surgical reconstruction with autologous grafts is widely employed in the international literature. Controversies remain with respect to technique variations as continuous research for improvement takes place. One of these variations is the anatomical double bundle technique, which is performed instead of the conventional single bundle technique. More recently, there has been a tendency towards positioning the two bundles through double bone tunnels in the femur and tibia (anatomical reconstruction. OBJECTIVES: To compare, through biomechanical tests, the practice of anatomical double bundle anterior cruciate ligament reconstruction with a patellar graft to conventional single bundle reconstruction with the same amount of patellar graft in a paired experimental cadaver study. METHODS: Nine pairs of male cadaver knees ranging in age from 44 to 63 years were randomized into two groups: group A (single bundle and group B (anatomical reconstruction. Each knee was biomechanically tested under three conditions: intact anterior cruciate ligament, reconstructed anterior cruciate ligament, and injured anterior cruciate ligament. Maximum anterior dislocation, rigidity, and passive internal tibia rotation were recorded with knees submitted to a 100 N horizontal anterior dislocation force applied to the tibia with the knees at 30, 60 and 90 degrees of flexion. RESULTS: There were no differences between the two techniques for any of the measurements by ANOVA tests. CONCLUSION: The technique of anatomical double bundle reconstruction of the anterior cruciate ligament with bone-patellar tendon-bone graft has a similar biomechanical behavior with regard to anterior tibial dislocation, rigidity, and passive internal tibial rotation.

  13. Improvements to Wire Bundle Thermal Modeling for Ampacity Determination

    Science.gov (United States)

    Rickman, Steve L.; Iannello, Christopher J.; Shariff, Khadijah

    2017-01-01

    Determining current carrying capacity (ampacity) of wire bundles in aerospace vehicles is critical not only to safety but also to efficient design. Published standards provide guidance on determining wire bundle ampacity but offer little flexibility for configurations where wire bundles of mixed gauges and currents are employed with varying external insulation jacket surface properties. Thermal modeling has been employed in an attempt to develop techniques to assist in ampacity determination for these complex configurations. Previous developments allowed analysis of wire bundle configurations but was constrained to configurations comprised of less than 50 elements. Additionally, for vacuum analyses, configurations with very low emittance external jackets suffered from numerical instability in the solution. A new thermal modeler is presented allowing for larger configurations and is not constrained for low bundle infrared emissivity calculations. Formulation of key internal radiation and interface conductance parameters is discussed including the effects of temperature and air pressure on wire to wire thermal conductance. Test cases comparing model-predicted ampacity and that calculated from standards documents are presented.

  14. Variable recruitment in bundles of miniature pneumatic artificial muscles.

    Science.gov (United States)

    DeLaHunt, Sylvie A; Pillsbury, Thomas E; Wereley, Norman M

    2016-09-13

    The natural compliance and force generation properties of pneumatic artificial muscles (PAMs) allow them to operate like human muscles in anthropomorphic robotic manipulators. Traditionally, manipulators use a single PAM or multiple PAMs actuated in unison in place of a human muscle. However, these standard manipulators can experience significant efficiency losses when operated outside their target performance ranges at low actuation pressures. This study considers the application of a variable recruitment control strategy to a parallel bundle of miniature PAMs as an attempt to mimic the selective recruitment of motor units in a human muscle. Bundles of miniature PAMs are experimentally characterized, their actuation behavior is modeled, and the efficiency gains and losses associated with the application of a variable recruitment control strategy are assessed. This bio-inspired control strategy allows muscle bundles to operate the fewest miniature PAMs necessary to achieve a desired performance objective, improving the muscle bundle's operating efficiency over larger ranges of force generation and displacement. The study also highlights the need for improved PAM fabrication techniques to facilitate the production of identical miniature PAMs for inclusion in muscle bundles.

  15. Thermal hydraulics of rod bundles: The effect of eccentricity

    Energy Technology Data Exchange (ETDEWEB)

    Chauhan, Amit K., E-mail: amit_fmlab@yahoo.co.in [Fluid Mechanics Laboratory, Department of Applied Mechanics, Indian Institute of Technology Madras, Chennai 600036 (India); Prasad, B.V.S.S.S., E-mail: prasad@iitm.ac.in [Thermal Turbomachines Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600036 (India); Patnaik, B.S.V., E-mail: bsvp@iitm.ac.in [Fluid Mechanics Laboratory, Department of Applied Mechanics, Indian Institute of Technology Madras, Chennai 600036 (India)

    2013-10-15

    Highlights: • Present CFD investigation explores, whole bundle eccentricity for the first time. • Fluid flow and thermal characteristics in various subchannels are analyzed. • Mass flux distribution is particularly analyzed to study eccentricity effect. • Higher eccentricity resulted in a shoot up in rod surface temperature distribution. • Both tangential and radial flow in rod bundles has resulted due to eccentricity. -- Abstract: The effect of eccentricity on the fluid flow and heat transfer through a 19-rod bundle is numerically carried out. When the whole bundle shifts downwards with respect to the outer (pressure) tube, flow redistribution happens. This in turn is responsible for changes in mass flux, pressure and differential flow development in various subchannels. The heat flux imposed on the surface of the fuel rods and the mass flux through the subchannels determines the coolant outlet temperatures. The simulations are performed for a coolant flow Reynolds number of 4 × 10{sup 5}. For an eccentricity value of 0.7, the mass flux in the bottom most subchannel (l) was found to decrease by 10%, while the surface temperature of the fuel rod in the vicinity of this subchannel increased by 250% at the outlet section. Parameters of engineering interest including skin friction coefficient, Nusselt number, etc., have been systematically explored to study the effect of eccentricity on the rod bundle.

  16. Dynamic response of fiber bundle under transverse impact.

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Wei-Yang; Song, Bo

    2010-03-01

    There has been a very high demand in developing efficient soft body armors to protect the military and law enforcement personnel from ballistic or explosive attack. As a basic component in the soft body armor, fibers or fiber bundles play a key role in the performance against ballistic impact. In order to study the ballistic-resistant mechanism of the soft body armor, it is desirable to understand the dynamic response of the fiber bundle under transverse impact. Transverse wave speed is one important parameter because a faster transverse wave speed can make the impact energy dissipate more quickly. In this study, we employed split Hopkinson pressure bar (SHPB) to generate constant high-speed impact on a Kevlar fiber bundle in the transverse direction. The deformation of the fiber bundle was photographed with high-speed digital cameras. The transverse wave speeds were experimentally measured at various transverse impact velocities. The experimental results can also be used to quantitatively verify the current analytical models or to develop new models to describe the dynamic response of fiber bundle under transverse impact.

  17. Pressure Loss across Tube Bundles in Two-phase Flow

    Energy Technology Data Exchange (ETDEWEB)

    Sim, Woo Gun; Banzragch, Dagdan [Hannam Univ., Daejon (Korea, Republic of)

    2016-03-15

    An analytical model was developed by Sim to estimate the two-phase damping ratio for upward two-phase flow perpendicular to horizontal tube bundles. The parameters of two-phase flow, such as void fraction and pressure loss evaluated in the model, were calculated based on existing experimental formulations. However, it is necessary to implement a few improvements in the formulations for the case of tube bundles. For the purpose of the improved formulation, we need more information about the two-phase parameters, which can be found through experimental test. An experiment is performed with a typical normal square array of cylinders subjected to the two-phase flow of air-water in the tube bundles, to calculate the two-phase Euler number and the two-phase friction multiplier. The pitch-to-diameter ratio is 1.35 and the diameter of cylinder is 18mm. Pressure loss along the flow direction in the tube bundles is measured with a pressure transducer and data acquisition system to calculate the two-phase Euler number and the two-phase friction multiplier. The void fraction model by Feenstra et al. is used to estimate the void fraction of the two-phase flow in tube bundles. The experimental results of the two phase friction multiplier and two-phase Euler number for homogeneous and non-homogeneous two-phase flows are compared and evaluated against the analytical results given by Sim's model.

  18. Ecosystem service bundles for analyzing tradeoffs in diverse landscapes

    Science.gov (United States)

    Raudsepp-Hearne, C.; Peterson, G. D.; Bennett, E. M.

    2010-01-01

    A key challenge of ecosystem management is determining how to manage multiple ecosystem services across landscapes. Enhancing important provisioning ecosystem services, such as food and timber, often leads to tradeoffs between regulating and cultural ecosystem services, such as nutrient cycling, flood protection, and tourism. We developed a framework for analyzing the provision of multiple ecosystem services across landscapes and present an empirical demonstration of ecosystem service bundles, sets of services that appear together repeatedly. Ecosystem service bundles were identified by analyzing the spatial patterns of 12 ecosystem services in a mixed-use landscape consisting of 137 municipalities in Quebec, Canada. We identified six types of ecosystem service bundles and were able to link these bundles to areas on the landscape characterized by distinct social–ecological dynamics. Our results show landscape-scale tradeoffs between provisioning and almost all regulating and cultural ecosystem services, and they show that a greater diversity of ecosystem services is positively correlated with the provision of regulating ecosystem services. Ecosystem service-bundle analysis can identify areas on a landscape where ecosystem management has produced exceptionally desirable or undesirable sets of ecosystem services. PMID:20194739

  19. A Macrocyclic Peptide that Serves as a Cocrystallization Ligand and Inhibits the Function of a MATE Family Transporter

    Directory of Open Access Journals (Sweden)

    Hiroaki Suga

    2013-08-01

    Full Text Available The random non-standard peptide integrated discovery (RaPID system has proven to be a powerful approach to discover de novo natural product-like macrocyclic peptides that inhibit protein functions. We have recently reported three macrocyclic peptides that bind to Pyrococcus furiosus multidrug and toxic compound extrusion (PfMATE transporter and inhibit the transport function. Moreover, these macrocyclic peptides were successfully employed as cocrystallization ligands of selenomethionine-labeled PfMATE. In this report, we disclose the details of the RaPID selection strategy that led to the identification of these three macrocyclic peptides as well as a fourth macrocyclic peptide, MaD8, which is exclusively discussed in this article. MaD8 was found to bind within the cleft of PfMATE’s extracellular side and blocked the path of organic small molecules being extruded. The results of an ethidium bromide efflux assay confirmed the efflux inhibitory activity of MaD8, whose behavior was similar to that of previously reported MaD5.

  20. Synthesis, crystal structures and properties of two novel macrocyclic nickel(II) and copper(II) complexes

    Science.gov (United States)

    Su, Yan-Hui; Liu, Jie; Li, Jia; Si, Xue-Zhi

    2007-06-01

    Two new 14-membered hexaaza macrocyclic complexes with the formulae [NiL](ClO 4) 2·CH 3COCH 3 ( 1) and [CuL](ClO 4) 2·CH 3COCH 3 ( 2), where L = 3,10-bis(2-thiophenemethyl)-1,3,5,8,10,12-hexaazacyclotetradecane, have been synthesized and characterized by elemental analyses, single-crystal X-ray diffraction analyses, electronic spectra, IR and TG-DTA. In 1, the nickel(II) ion is four-coordinated with four nitrogen atoms from the macrocycle and forms a square-planar coordination geometry. In 2, the copper(II) ion is six-coordinated with four nitrogen atoms from the macrocyclic ligand in the equatorial plane and two oxygen atoms from the perchlorate anions in the axial position exhibiting an elongated octahedron coordination geometry. The two complexes present two different molecular arrangements in which the [ML] 2+ (M = Ni, Cu) cation arrays in the manner of M(1)M(2)M(1)… in sequence. The pendant thiophene groups of the neighboring macrocycles have no π⋯π interactions. All the ClO4- anions and acetone molecules are involved in hydrogen-bonding interactions with the macrocyclic ligand.

  1. Peptide Macrocycles Featuring a Backbone Secondary Amine: A Convenient Strategy for the Synthesis of Lipidated Cyclic and Bicyclic Peptides on Solid Support

    DEFF Research Database (Denmark)

    Oddo, Alberto; Münzker, Lena; Hansen, Paul Robert

    2015-01-01

    A convenient strategy for the on-resin synthesis of macrocyclic peptides (3- to 13-mers) via intramolecular halide substitution by a diamino acid is described. The method is compatible with standard Fmoc/tBu SPPS and affords a tail-to-side-chain macrocyclic peptide featuring an endocyclic secondary...

  2. Failure of a MEA reclaimer tube bundle due to corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Shaban, H.; Abdo, M.S.E.; Lal, D.P.

    1988-08-01

    The removal of sulphur compounds from natural gas used in ammonia production is carried out by scrubbing with monoethanol amine (MEA). To avoid build up of corrosion and degradation products, a portion of the circulating MEA solution is passed through a reclaimer. This is essentially a kettle-type reboiler with a tube bundle made of 316L stainless steel. Occasional failures of the tube bundle due to pitting corrosion have been reported. It is suggested that the excessive pitting corrosion observed on the upper rows of the tube bundle could be partly due to high steam temperature but mainly due to the liquid level falling below the tubes leaving an accumulation of corrosive degradation products on the exposed surfaces, normally these corrosive products remain diluted in the MEA solution and cause little corrosion of the covered tubes. Their concentration on the dry upper layers of the hot metal tubes, however, leads to excessive corrosion. (U.K.).

  3. On the motives of moduli of chains and Higgs bundles

    CERN Document Server

    García-Prada, Oscar; Schmitt, Alexander

    2011-01-01

    We take another approach to Hitchin's strategy of computing the cohomology of moduli spaces of Higgs bundles by localization with respect to the circle-action. Our computation is done in the dimensional completion of the Grothendieck ring of varieties and starts by describing the classes of moduli stacks of chains rather than their coarse moduli spaces. As an application we show that the n-torsion of the Jacobian acts trivially on the middle dimensional cohomology of the moduli space of twisted SL_n-Higgs-bundles of degree coprime to n and we give an explicit formula for the motive of the moduli space of Higgs bundles of rank 4 and odd degree. This provides new evidence for a conjecture of Hausel and Rodr\\'iguez-Villegas. Along the way we find explicit recursion formulas for the motives of several types of moduli spaces of stable chains.

  4. Rheology of semiflexible bundle networks with transient linkers.

    Science.gov (United States)

    Müller, Kei W; Bruinsma, Robijn F; Lieleg, Oliver; Bausch, Andreas R; Wall, Wolfgang A; Levine, Alex J

    2014-06-13

    We present a theoretical and computational analysis of the rheology of networks made up of bundles of semiflexible filaments bound by transient cross-linkers. Such systems are ubiquitous in the cytoskeleton and can be formed in vitro using filamentous actin and various cross-linkers. We find that their high-frequency rheology is characterized by a scaling behavior that is quite distinct from that of networks of the well-studied single semiflexible filaments. This regime can be understood theoretically in terms of a length-scale-dependent bending modulus for bundles. Next, we observe new dissipative dynamics associated with the shear-induced disruption of the network at intermediate frequencies. Finally, at low frequencies, we encounter a region of non-Newtonian rheology characterized by power-law scaling. This regime is dominated by bundle dissolution and large-scale rearrangements of the network driven by equilibrium thermal fluctuations.

  5. DTI Image Registration under Probabilistic Fiber Bundles Tractography Learning

    Science.gov (United States)

    Lei, Tao; Fan, Yangyu; Zhang, Xiuwei

    2016-01-01

    Diffusion Tensor Imaging (DTI) image registration is an essential step for diffusion tensor image analysis. Most of the fiber bundle based registration algorithms use deterministic fiber tracking technique to get the white matter fiber bundles, which will be affected by the noise and volume. In order to overcome the above problem, we proposed a Diffusion Tensor Imaging image registration method under probabilistic fiber bundles tractography learning. Probabilistic tractography technique can more reasonably trace to the structure of the nerve fibers. The residual error estimation step in active sample selection learning is improved by modifying the residual error model using finite sample set. The calculated deformation field is then registered on the DTI images. The results of our proposed registration method are compared with 6 state-of-the-art DTI image registration methods under visualization and 3 quantitative evaluation standards. The experimental results show that our proposed method has a good comprehensive performance.

  6. Narrow muon bundles from muon pair production in rock

    CERN Document Server

    Kudryavtsev, V A; Spooner, N J C

    1999-01-01

    We revise the process of muon pair production by high-energy muons in rock using the recently published cross-section. The three- dimensional Monte Carlo code MUSIC has been used to obtain the characteristics of the muon bundles initiated via this process. We have compared them with those of conventional muon bundles initiated in the atmosphere and shown that large underground detectors, capable of collecting hundreds of thousands of multiple muon events, can discriminate statistically muon induced bundles from conventional ones. However, we find that the enhancement of the measured muon decoherence function over that predicted at small distances, recently reported by the MACRO experiment, cannot be explained by the effect of muon pair production alone, unless its cross-section is underestimated by a factor of 3. (20 refs).

  7. Narrow muon bundles from muon pair production in rock

    CERN Document Server

    Kudryavtsev, V A; Spooner, N J C; 10.1016/S0370-2693(99)01378-7

    2009-01-01

    We revise the process of muon pair production by high-energy muons in rock using the recently published cross-section. The three-dimensional Monte Carlo code MUSIC has been used to obtain the characteristics of the muon bundles initiated via this process. We have compared them with those of conventional muon bundles initiated in the atmosphere and shown that large underground detectors, capable of collecting hundreds of thousands of multiple muon events, can discriminate statistically muon induced bundles from conventional ones. However, we find that the enhancement of the measured muon decoherence function over that predicted at small distances, recently reported by the MACRO experiment, cannot be explained by the effect of muon pair production alone, unless its cross-section is underestimated by a factor of 3.

  8. High-order synchronization of hair cell bundles

    Science.gov (United States)

    Levy, Michael; Molzon, Adrian; Lee, Jae-Hyun; Kim, Ji-Wook; Cheon, Jinwoo; Bozovic, Dolores

    2016-12-01

    Auditory and vestibular hair cell bundles exhibit active mechanical oscillations at natural frequencies that are typically lower than the detection range of the corresponding end organs. We explore how these noisy nonlinear oscillators mode-lock to frequencies higher than their internal clocks. A nanomagnetic technique is used to stimulate the bundles without an imposed mechanical load. The evoked response shows regimes of high-order mode-locking. Exploring a broad range of stimulus frequencies and intensities, we observe regions of high-order synchronization, analogous to Arnold Tongues in dynamical systems literature. Significant areas of overlap occur between synchronization regimes, with the bundle intermittently flickering between different winding numbers. We demonstrate how an ensemble of these noisy spontaneous oscillators could be entrained to efficiently detect signals significantly above the characteristic frequencies of the individual cells.

  9. Symposium on Singularities, Representation of Algebras, and Vector Bundles

    CERN Document Server

    Trautmann, Günther

    1987-01-01

    It is well known that there are close relations between classes of singularities and representation theory via the McKay correspondence and between representation theory and vector bundles on projective spaces via the Bernstein-Gelfand-Gelfand construction. These relations however cannot be considered to be either completely understood or fully exploited. These proceedings document recent developments in the area. The questions and methods of representation theory have applications to singularities and to vector bundles. Representation theory itself, which had primarily developed its methods for Artinian algebras, starts to investigate algebras of higher dimension partly because of these applications. Future research in representation theory may be spurred by the classification of singularities and the highly developed theory of moduli for vector bundles. The volume contains 3 survey articles on the 3 main topics mentioned, stressing their interrelationships, as well as original research papers.

  10. 4d SCFTs from negative-degree line bundles

    CERN Document Server

    Nardoni, Emily

    2016-01-01

    We construct 4d $\\mathcal{N}=1$ quantum field theories by compactifying the (2,0) theories on a Riemann surface with genus $g$ and $n$ punctures, where the normal bundle decomposes into a sum of two line bundles with possibly negative degrees $p$ and $q$. Until recently, the only available field-theoretic constructions required the line bundle degrees to be nonnegative, although supergravity solutions were constructed in the literature for the zero-puncture case for all $p$ and $q$. Here, we provide field-theoretic constructions and computations of the central charges of 4d $\\mathcal{N}=1$ SCFTs that are the IR limit of M5-branes wrapping a surface with general $p$ or $q$ negative, for general genus $g$ and number of maximal punctures $n$.

  11. Simulation of bundle test Quench-12 with integral code MELCOR

    Energy Technology Data Exchange (ETDEWEB)

    Duspiva, J. [Nuclear Research Inst., Rez plc (Czech Republic)

    2011-07-01

    The past NRI analyses cover the Quench-01, Quench-03 and Quench-06 with version MELCOR 1.8.5 (including reflood model), and Quench-01 and Quench-11 tests with the latest version MELCOR 1.8.6. The Quench-12 test is specific, because it has different bundle configuration related to the VVER bundle configuration with hexagonal grid of pins and also used E110 cladding material. Specificity of Quench-12 test is also in the used material of fuel rod cladding - E110. The test specificities are a reason for the highest concern, because the VVER reactors are operated in the Czech Republic. The new input model was developed with the taking into account all experience from previous simulations of the Quench bundle tests. The recent version MELCOR 1.8.6 YU{sub 2}911 was used for the simulation with slightly modified ELHEAT package. Sensitivity studies on input parameters and oxidation kinetics were performed. (author)

  12. Lesson Eleven Transient and intermittent left bundle branch block

    Institute of Scientific and Technical Information of China (English)

    鲁端; 王劲

    2004-01-01

    @@ In transient left bundle branch block,normal intraventricular conduction subsequently returns,if only1temporarily.The condition has also been called paroxysmal,unstable,or temporary left bundle branch block. Its etiology is similar to that of the stable variety2, with the great majority of the patients having ischemic or hypertensive heart disease or both. Transient bundle branch block may complicate acute myocardial infarction or may occur during attacks of angina. It may appear during an episode of congestive heart failure and disappear with improvement of the cardiac status. Most patients eventually develop permanent block. Occasionally,however, the patient may revert to normal conduction even years after consistently demonstrating the block.

  13. Multi-scale strain-stiffening of semiflexible bundle networks

    CERN Document Server

    Piechocka, I K; Broedersz, C P; Kurniawan, N A; MacKintosh, F C; Koenderink, G H

    2015-01-01

    Bundles of polymer filaments are responsible for the rich and unique mechanical behaviors of many biomaterials, including cells and extracellular matrices. In fibrin biopolymers, whose nonlinear elastic properties are crucial for normal blood clotting, protofibrils self-assemble and bundle to form networks of semiflexible fibers. Here we show that the extraordinary strain-stiffening response of fibrin networks is a direct reflection of the hierarchical architecture of the fibrin fibers. We measure the rheology of networks of unbundled protofibrils and find excellent agreement with an affine model of extensible wormlike polymers. By direct comparison with these data, we show that physiological fibrin networks composed of thick fibers can be modeled as networks of tight protofibril bundles. We demonstrate that the tightness of coupling between protofibrils in the fibers can be tuned by the degree of enzymatic intermolecular crosslinking by the coagulation Factor XIII. Furthermore, at high stress, the protofibri...

  14. Real Parabolic Vector Bundles over a Real Curve

    Indian Academy of Sciences (India)

    Sanjay Amrutiya

    2014-02-01

    We define real parabolic structures on real vector bundles over a real curve. Let $(X, _X)$ be a real curve, and let $S\\subset X$ be a non-empty finite subset of such that $_X(S) = S$. Let ≥ 2 be an integer. We construct an -fold cyclic cover : $Y→ X$ in the category of real curves, ramified precisely over each point of , and with the property that for any element of the Galois group , and any $y\\in Y$, one has $_Y(gy) = g^{-1}_Y(y)$. We established an equivalence between the category of real parabolic vector bundles on $(X,_X)$ with real parabolic structure over , all of whose weights are integral multiples of 1/, and the category of real -equivariant vector bundles on $(Y, _Y)$.

  15. The Family Problem: Hints from Heterotic Line Bundle Models

    CERN Document Server

    Constantin, Andrei; Mishra, Challenger

    2015-01-01

    Within the class of heterotic line bundle models, we argue that N=1 vacua which lead to a small number of low-energy chiral families are preferred. By imposing an upper limit on the volume of the internal manifold, as required in order to obtain finite values of the four-dimensional gauge couplings, and validity of the supergravity approximation we show that, for a given manifold, only a finite number of line bundle sums are consistent with supersymmetry. By explicitly scanning over this finite set of line bundle models on certain manifolds we show that, for a sufficiently small volume of the internal manifold, the family number distribution peaks at small values, consistent with three chiral families. The relation between the maximal number of families and the gauge coupling is discussed, which hints towards a possible explanation of the family problem.

  16. Magnetic Propulsion of Microswimmers with DNA-Based Flagellar Bundles.

    Science.gov (United States)

    Maier, Alexander M; Weig, Cornelius; Oswald, Peter; Frey, Erwin; Fischer, Peer; Liedl, Tim

    2016-02-10

    We show that DNA-based self-assembly can serve as a general and flexible tool to construct artificial flagella of several micrometers in length and only tens of nanometers in diameter. By attaching the DNA flagella to biocompatible magnetic microparticles, we provide a proof of concept demonstration of hybrid structures that, when rotated in an external magnetic field, propel by means of a flagellar bundle, similar to self-propelling peritrichous bacteria. Our theoretical analysis predicts that flagellar bundles that possess a length-dependent bending stiffness should exhibit a superior swimming speed compared to swimmers with a single appendage. The DNA self-assembly method permits the realization of these improved flagellar bundles in good agreement with our quantitative model. DNA flagella with well-controlled shape could fundamentally increase the functionality of fully biocompatible nanorobots and extend the scope and complexity of active materials.

  17. Gradient Bundle Analysis: A Full Topological Approach to Chemical Bonding

    CERN Document Server

    Morgenstern, Amanda

    2016-01-01

    The "chemical bond" is a central concept in molecular sciences, but there is no consensus as to what a bond actually is. Therefore, a variety of bonding models have been developed, each defining the structure of molecules in a different manner with the goal of explaining and predicting chemical properties. This thesis describes the initial development of gradient bundle analysis (GBA), a chemical bonding model that creates a high resolution picture of chemical interactions within the charge density framework. GBA is based on concepts from the quantum theory of atoms in molecules (QTAIM), but uses a more complete picture of the topology and geometry of the electron charge density to understand and predict bonding interactions. Gradient bundles are defined as volumes bounded by zero-flux surfaces (ZFSs) in the gradient of the charge density with well-defined energies. The structure of gradient bundles provides an avenue for detecting the locations of valence electrons, which correspond to reactive regions in a ...

  18. The Analysis of SBWR Critical Power Bundle Using Cobrag Code

    Directory of Open Access Journals (Sweden)

    Yohannes Sardjono

    2013-03-01

    Full Text Available The coolant mechanism of SBWR is similar with the Dodewaard Nuclear Power Plant (NPP in the Netherlands that first went critical in 1968. The similarity of both NPP is cooled by natural convection system. These coolant concept is very related with same parameters on fuel bundle design especially fuel bundle length, core pressure drop and core flow rate as well as critical power bundle. The analysis was carried out by using COBRAG computer code. COBRAG computer code is GE Company proprietary. Basically COBRAG computer code is a tool to solve compressible three-dimensional, two fluid, three field equations for two phase flow. The three fields are the vapor field, the continuous liquid field, and the liquid drop field. This code has been applied to analyses model flow and heat transfer within the reactor core. This volume describes the finitevolume equations and the numerical solution methods used to solve these equations. This analysis of same parameters has been done i.e.; inlet sub cooling 20 BTU/lbm and 40 BTU/lbm, 1000 psi pressure and R-factor is 1.038, mass flux are 0.5 Mlb/hr.ft2, 0.75 Mlb/hr.ft2, 1.00 Mlb/hr.ft2 and 1.25 Mlb/hr.ft2. Those conditions based on history operation of some type of the cell fuel bundle line at GE Nuclear Energy. According to the results, it can be concluded that SBWR critical power bundle is 10.5 % less than current BWR critical power bundle with length reduction of 12 ft to 9 ft.

  19. Single-molecule phenyl-acetylene-macrocycle-based optoelectronic switch functioning as a quantum-interference-effect transistor.

    Science.gov (United States)

    Hsu, Liang-Yan; Rabitz, Herschel

    2012-11-02

    This work proposes a new type of optoelectronic switch, the phenyl-acetylene-macrocycle-based single-molecule transistor, which utilizes photon-assisted tunneling and destructive quantum interference. The analysis uses single-particle Green's functions along with Floquet theory. Without the optical field, phenyl-acetylene-macrocycle exhibits a wide range of strong antiresonance between its frontier orbitals. The simulations show large on-off ratios (over 10(4)) and measurable currents (~10(-11) A) enabled by photon-assisted tunneling in a weak optical field (~2 × 10(5) V/cm) and at a small source-drain voltage (~0.05 V). Field amplitude power scaling laws and a range of field intensities are given for operating one- and two-photon assisted tunneling in phenyl-acetylene-macrocycle-based single-molecule transistors. This development opens up a new direction for creating molecular switches.

  20. Highly efficient synthesis of monodisperse poly(ethylene glycols) and derivatives through macrocyclization of oligo(ethylene glycols).

    Science.gov (United States)

    Zhang, Hua; Li, Xuefei; Shi, Qiuyan; Li, Yu; Xia, Guiquan; Chen, Long; Yang, Zhigang; Jiang, Zhong-Xing

    2015-03-16

    A macrocyclic sulfate (MCS)-based approach to monodisperse poly(ethylene glycols) (M-PEGs) and their monofunctionalized derivatives has been developed. Macrocyclization of oligo(ethylene glycols) (OEGs) provides MCS (up to a 62-membered macrocycle) as versatile precursors for a range of monofunctionalized M-PEGs. Through iterative nucleophilic ring-opening reactions of MCS without performing group protection and activation, a series of M-PEGs, including the unprecedented 64-mer (2850 Da), can be readily prepared. Synthetic simplicity coupled with versatility of this new strategy may pave the way for broader applications of M-PEGs. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Discovery and Optimization of Macrocyclic Quinoxaline-pyrrolo-dihydropiperidinones as Potent Pim-1/2 Kinase Inhibitors.

    Science.gov (United States)

    Cee, Victor J; Chavez, Frank; Herberich, Bradley; Lanman, Brian A; Pettus, Liping H; Reed, Anthony B; Wu, Bin; Wurz, Ryan P; Andrews, Kristin L; Chen, Jie; Hickman, Dean; Laszlo, Jimmy; Lee, Matthew R; Guerrero, Nadia; Mattson, Bethany K; Nguyen, Yen; Mohr, Christopher; Rex, Karen; Sastri, Christine E; Wang, Paul; Wu, Qiong; Wu, Tian; Xu, Yang; Zhou, Yihong; Winston, Jeffrey T; Lipford, J Russell; Tasker, Andrew S; Wang, Hui-Ling

    2016-04-14

    The identification of Pim-1/2 kinase overexpression in B-cell malignancies suggests that Pim kinase inhibitors will have utility in the treatment of lymphoma, leukemia, and multiple myeloma. Starting from a moderately potent quinoxaline-dihydropyrrolopiperidinone lead, we recognized the potential for macrocyclization and developed a series of 13-membered macrocycles. The structure-activity relationships of the macrocyclic linker were systematically explored, leading to the identification of 9c as a potent, subnanomolar inhibitor of Pim-1 and -2. This molecule also potently inhibited Pim kinase activity in KMS-12-BM, a multiple myeloma cell line with relatively high endogenous levels of Pim-1/2, both in vitro (pBAD IC50 = 25 nM) and in vivo (pBAD EC50 = 30 nM, unbound), and a 100 mg/kg daily dose was found to completely arrest the growth of KMS-12-BM xenografts in mice.

  2. Chern-Simons functional under gauge transformations on flat bundles

    Science.gov (United States)

    Byun, Yanghyun; Kim, Joohee

    2017-01-01

    We describe the effect of a gauge transformation on the Chern-Simons functional in a thorough and unifying manner. We use the assumptions that the structure group is compact and connected and, in particular, that the principal bundle is flat. The Chern-Simons functional we consider is the one defined by choosing a flat reference connection. The most critical step in arriving at the main result is to show both the existence and the uniqueness of a cohomology class on the adjoint bundle such that it is the class of the so-called Maurer-Cartan 3-form when restricted to each fiber.

  3. BUNDLE ADJUSTMENTS CCD CAMERA CALIBRATION BASED ON COLLINEARITY EQUATION

    Institute of Scientific and Technical Information of China (English)

    Liu Changying; Yu Zhijing; Che Rensheng; Ye Dong; Huang Qingcheng; Yang Dingning

    2004-01-01

    The solid template CCD camera calibration method of bundle adjustments based on collinearity equation is presented considering the characteristics of space large-dimension on-line measurement. In the method, a more comprehensive camera model is adopted which is based on the pinhole model extended with distortions corrections. In the process of calibration, calibration precision is improved by imaging at different locations in the whole measurement space, multi-imaging at the same location and bundle adjustments optimization. The calibration experiment proves that the calibration method is able to fulfill calibration requirement of CCD camera applied to vision measurement.

  4. Cellulosic Fibers: Effect of Processing on Fiber Bundle Strength

    DEFF Research Database (Denmark)

    Thygesen, Anders; Madsen, Bo; Thomsen, Anne Belinda;

    2011-01-01

    A range of differently processed cellulosic fibers from flax and hemp plants were investigated to study the relation between processing of cellulosic fibers and fiber bundle strength. The studied processing methods are applied for yarn production and include retting, scutching, carding, and cotto......A range of differently processed cellulosic fibers from flax and hemp plants were investigated to study the relation between processing of cellulosic fibers and fiber bundle strength. The studied processing methods are applied for yarn production and include retting, scutching, carding...

  5. Dialytic Separation of Bundled, Functionalized Carbon Nanotubes from Carbonaceous Impurities

    Directory of Open Access Journals (Sweden)

    J. Justin Mulvey

    2014-11-01

    Full Text Available Separating functionalized single-wall carbon nanotubes (SWCNTs from functionalized amorphous carbon is challenging, due to their polydispersity and similar physicochemical properties. We describe a single-step, dialytic separation method that takes advantage of the ability of heavily functionalized SWCNTs to bundle in a polar environment while maintaining their solubility. Experiments on functionalized SWCNTs were compared with functionalized, C60 fullerenes (buckyballs to probe the general applicability of the method and further characterize the bundling process. This approach may simultaneously be used to purify a functionalization reaction mixture of unreacted small molecules and of residual solvents, such as dimethylformamide.

  6. Milnor-Wood type inequalities for Higgs bundles

    CERN Document Server

    Hartnick, Tobias

    2011-01-01

    We explain how the generalized Milnor-Wood inequality of Burger and Iozzi for reductive representations of a cocompact complex-hyperbolic lattice into a Hermitian Lie group translates under Simpson's non-abelian Hodge correspondence into an inequality for topological invariants of the corresponding Higgs bundles. In this way, we obtain an inequality that holds for all Hermitian Lie groups, generalizing the Milnor-Wood type inequalities for Higgs bundles that have been proved for the classical Hermitian Lie groups by Bradlow, Garcia-Prada, and Gothen and by Koziarz and Maubon.

  7. Einstein Manifolds, Abelian Instantons, Bundle Reduction, and the Cosmological Constant

    CERN Document Server

    Soo, C P

    2001-01-01

    The anti-self-dual projection of the spin connections of certain four-dimensional Einstein manifolds can be Abelian in nature. These configurations signify bundle reductions. By a theorem of Kobayashi and Nomizu such a process is predicated on the existence of a covariantly constant field. It turns out that even without fundamental Higgs fields and other physical matter, gravitational self-interactions can generate this mechanism if the cosmological constant is non-vanishing. This article identifies the order parameter, and clarifies how these Abelian instanton solutions are associated with a Higgs triplet which causes the bundle reduction from SO(3) gauge group to U(1).

  8. Arthroscopic double-bundle posterior cruciate ligament reconstruction surgical technique.

    Science.gov (United States)

    Fanelli, Gregory C; Beck, John D; Edson, Craig J

    2010-06-01

    The keys to successful posterior cruciate ligament (PCL) reconstruction are to identify and treat all pathology, use strong graft material, accurately place tunnels in anatomic insertion sites, minimize graft bending, use a mechanical graft tensioning device, use primary and back-up graft fixation, and use the appropriate postoperative rehabilitation program. Adherence to these technical principles results in successful single-bundle and double-bundle arthroscopic transtibial tunnel PCL reconstruction based on stress radiography, arthrometer, knee ligament rating scales, and patient satisfaction measurements.

  9. Capillary Micro-Flow Through a Fiber Bundle(Ⅰ)

    Institute of Scientific and Technical Information of China (English)

    ZHU Ying-dan; WANG Ji-hui; TAN Hua; GAO Guo-qiang

    2004-01-01

    The present work considered the capillary micro-flow through a fiber bundle. The resin heights in the fiber bundle as a function of time were used to determine the experimental values of capillary pressure and the permeability by the nonlinear regression fitting method. The fitting curves showed a good agreement with experiments. However, these values of capillary pressure from short- time experiments were much lower than the theoretical results from the Yang-Laplace Equation. More accurate capillary pressure was predicted from the presented long-run experiment.

  10. Dunkl Operators as Covariant Derivatives in a Quantum Principal Bundle

    Science.gov (United States)

    Durdevich, Micho; Sontz, Stephen Bruce

    2013-05-01

    A quantum principal bundle is constructed for every Coxeter group acting on a finite-dimensional Euclidean space E, and then a connection is also defined on this bundle. The covariant derivatives associated to this connection are the Dunkl operators, originally introduced as part of a program to generalize harmonic analysis in Euclidean spaces. This gives us a new, geometric way of viewing the Dunkl operators. In particular, we present a new proof of the commutativity of these operators among themselves as a consequence of a geometric property, namely, that the connection has curvature zero.

  11. Dunkl Operators as Covariant Derivatives in a Quantum Principal Bundle

    Directory of Open Access Journals (Sweden)

    Micho Đurđevich

    2013-05-01

    Full Text Available A quantum principal bundle is constructed for every Coxeter group acting on a finite-dimensional Euclidean space E, and then a connection is also defined on this bundle. The covariant derivatives associated to this connection are the Dunkl operators, originally introduced as part of a program to generalize harmonic analysis in Euclidean spaces. This gives us a new, geometric way of viewing the Dunkl operators. In particular, we present a new proof of the commutativity of these operators among themselves as a consequence of a geometric property, namely, that the connection has curvature zero.

  12. Dunkl Operators as Covariant Derivatives in a Quantum Principal Bundle

    CERN Document Server

    evich, Micho Đurđ

    2011-01-01

    A quantum principal bundle is constructed for every Coxeter group acting on a finite-dimensional Euclidean space E, and then a connection is also defined on this bundle. The covariant derivatives associated to this connection are the Dunkl operators, originally introduced as part of a program to generalize harmonic analysis in Euclidean spaces. This gives us a new, geometric way of viewing the Dunkl operators. In particular, we present a new proof of the commutivity of these operators among themselves as a consequence of a geometric property, namely, that the connection has curvature zero.

  13. Quillen Bundle and Geometric Prequantization of Non-Abelian Vortices on a Riemann Surface

    Indian Academy of Sciences (India)

    Rukmini Dey; Samir K Paul

    2011-02-01

    In this paper we prequantize the moduli space of non-abelian vortices. We explicitly calculate the symplectic form arising from 2 metric and we construct a prequantum line bundle whose curvature is proportional to this symplectic form. The prequantum line bundle turns out to be Quillen’s determinant line bundle with a modified Quillen metric. Next, as in the case of abelian vortices, we construct line bundles over the moduli space whose curvatures form a family of symplectic forms which are parametrized by $\\Psi_0$, a section of a certain bundle. The equivalence of these prequantum bundles are discussed.

  14. The Determinant Bundle on the Moduli Space of Stable Triples over a Curve

    Indian Academy of Sciences (India)

    Indranil Biswas; N Raghavendra

    2002-08-01

    We construct a holomorphic Hermitian line bundle over the moduli space of stable triples of the form (1, 2, ), where 1 and 2 are holomorphic vector bundles over a fixed compact Riemann surface , and : 2 → 1 is a holomorphic vector bundle homomorphism. The curvature of the Chern connection of this holomorphic Hermitian line bundle is computed. The curvature is shown to coincide with a constant scalar multiple of the natural Kähler form on the moduli space. The construction is based on a result of Quillen on the determinant line bundle over the space of Dolbeault operators on a fixed ∞ Hermitian vector bundle over a compact Riemann surface.

  15. Immobilized copper(II) macrocyclic complex on MWCNTs with antibacterial activity

    Energy Technology Data Exchange (ETDEWEB)

    Tarlani, Aliakbar, E-mail: Tarlani@ccerci.ac.ir [Inorganic Nanostructures and Catalysts Research Lab., Chemistry & Chemical Engineering Research Center of Iran, Pajoohesh Blvd., km 17, Karaj Hwy, Tehran 14968-13151 (Iran, Islamic Republic of); Narimani, Khashayar [Inorganic Nanostructures and Catalysts Research Lab., Chemistry & Chemical Engineering Research Center of Iran, Pajoohesh Blvd., km 17, Karaj Hwy, Tehran 14968-13151 (Iran, Islamic Republic of); Mohammadipanah, Fatemeh; Hamedi, Javad [Department of Microbial Biotechnology, School of Biology and Center of Excellence in Phylogeny of Living Organisms, College of Science, University of Tehran, Tehran 14155-6455 (Iran, Islamic Republic of); University of Tehran Biocompound Collection (UTBC), Microbial Technology and Products Research Center, University of Tehran, Tehran (Iran, Islamic Republic of); Tahermansouri, Hasan [Department of Chemistry, Ayatollah Amoli Branch, Islamic Azad University, Amol (Iran, Islamic Republic of); Amini, Mostafa M. [Department of Chemistry, Shahid Behshti University, 1983963113, Tehran (Iran, Islamic Republic of)

    2015-06-30

    Graphical abstract: In an antibacterial test, grafted copper(II) macrocyclic complex on the surface of MWCNT showed higher antibacterial activity against Bacillus subtilis compared to the individual MWCNT-COOH and the complex. - Highlights: • Copper(II) tetraaza macrocyclic complex covalently bonded to modified MWCNT. • Grafting of the complex carried out via an interaction between −C(=O)Cl group and NH of the ligand. • The samples were subjected in an antibacterial assessment to compare their activity. • Immobilized complex showed higher antibacterial activity against Bacillus subtilis ATCC 6633 compared to separately MWCNT-C(C=O)-OH and CuTAM. - Abstract: In a new approach, a copper(II) tetraaza macrocyclic complex (CuTAM) was covalently bonded on modified multi-walled carbon nanotubes (MWCNTs). To achieve this purpose, MWCNTs were converted to MWCNT-COCl and then reacted to NH groups of TAM ligand. The prepared material was characterized by Fourier Transform Infrared (FT-IR), X-ray diffraction (XRD), Raman spectroscopy, thermal gravimetric analysis (TGA), and FESEM (field emission scanning electron microscopy). FT-IR and TGA demonstrated the presence of the organic moieties, and XRD proved that the structure of MWCNTs remained intact during the three modification steps. An increase in the I{sub D}/I{sub G} ratio in Raman spectra confirmed the surface modifications. Finally, the samples were subjected to an antibacterial assessment to compare their biological activity. The antibacterial test showed that the grafted complex on the surface of the nanotube (MWCNT-CO-CuTAM) has higher antibacterial activity against Bacillus subtilis ATCC 6633 than the MWCNT-COOH and CuTAM with 1000 and 2000 μg/mL.

  16. Macrocyclic Hepatitis C Virus NS3/4A Protease Inhibitors: An Overview of Medicinal Chemistry.

    Science.gov (United States)

    Pillaiyar, Thanigaimalai; Namasivayam, Vigneshwaran; Manickam, Manoj

    2016-01-01

    Hepatitis C virus (HCV) is a causative agent of hepatitis C infectious disease that primarily affects the liver, ranging in severity from a mild illness lasting a few weeks to a lifelong illness. The 9.6 kb RNA genome of HCV encodes approximately 3000 amino acid polyprotein that must be processed by host and viral proteases into both structural (S) and non-structural (NS) proteins, respectively. Targeting the serine protease NS3 with an activating factor NS4A, i.e., NS3/4A has been considered as one of the most attractive targets for the development of anti-HCV therapy. Although there is no vaccine available, antiviral medicines cure approximately 90% of the persons with hepatitis C infection. On the other hand, efficacy of these medications can be hampered due to the rapid drug and cross resistances. To date, all developed HCV NS3/4A inhibitors are mainly peptide-based compounds derived from the cleavage products of substrate. Specifically macrocyclic peptidomimetics have rapidly emerged as a classical NS3/4A protease inhibitors for treating the HCV infection. This review highlights the development of macrocyclic anti-HCV NS3/4A protease, as well as clinically important inhibitors developed from linear peptides, discovered during the last 12 years (2003-2015) from all sources, including laboratory synthetic methods, virtual screening and structure-based molecular docking studies. We emphasize the rationale behind the design, study of structure-activity relationships, and mechanism of inhibitions and cellular effect of the macrocyclic inhibitors.

  17. Kinetic Analysis for Macrocyclizations Involving Anionic Template at the Transition State

    Directory of Open Access Journals (Sweden)

    Vicente Martí-Centelles

    2012-01-01

    competitive oligomerization/polymerization processes yielding undesired oligomeric/polymeric byproducts. The effect of anions has also been included in the kinetic models, as they can act as catalytic templates in the transition state reducing and stabilizing the transition state. The corresponding differential equation systems for each kinetic model can be solved numerically. Through a comprehensive analysis of these results, it is possible to obtain a better understanding of the different parameters that are involved in the macrocyclization reaction mechanism and to develop strategies for the optimization of the desired processes.

  18. A flexible cyclophane: Design, synthesis, and structure of a multibridged tris-tetrathiafulvalene (TTF) macrocycle

    DEFF Research Database (Denmark)

    Takimiya, K.; Thorup, Niels; Becher, J.

    2000-01-01

    that the neutral molecules include two (3a) or one chloroform molecule (3b) as solvent of crystallization inside the cavity, whereas the I-3(-) salt of 3b, obtained by electrocrystallization, has a molecular structure which is different from that of the neutral molecule in that the cavity has completely collapsed.......The tris-tetrathiafulvalene (TTF) macrocycles 3 with a large end-cavity were effectively synthesized from the readily available tetrakis(cyanoethylthio)TTF by means of a selective deprotection/realkylation sequence followed by an intramolecular coupling reaction. Crystal structure analyses revealed...

  19. Biomechanical Assessment of the Strength of Volleyball Players in Different Stages of the Training Macrocycle

    Directory of Open Access Journals (Sweden)

    Śliwa Marcin

    2015-09-01

    Full Text Available Introduction. In order to help volleyball players achieve superior results, their coaches are constantly seeking new training methods. One of the methods used to improve the effectiveness of the training that is being implemented is conducting tests which make it possible to assess the player’s locomotor system in terms of its motor and biomechanical functions. The aim of the study was to determine the torque of the knee flexor and extensor muscles of volleyball players in three stages of the annual macrocycle.

  20. Synthesis of NLO polycarbonates via the ring-opening polymerization of macrocyclic prepolymers

    Science.gov (United States)

    Kulig, Joseph B.; Moore, Collin G.; Brittain, William J.; Gilmour, Sandra; Perry, Joseph W.

    1994-05-01

    The synthesis and characterization of polycarbonates and polyformals is described. Copolymers of bisphenol A (BPA) and either a triphenyloxazole (1) or phenylquinoxaline (2) monomer were prepared. The polycarbonate copolymers were prepared by ring-opening polymerization of macrocyclic prepolymers using a solvent-free process. Preliminary electro- optic measurements have been performed on the polycarbonate copolymers of BPA and 1. Polyformals have also been prepared by a conventional polymerization process involving the reaction of dichloromethane with different feed ratios of BPA and either 1 or 2. The glass transition temperature of either the polyformals or polycarbonates is dramatically increased by increasing mole fractions of monomers 1 and 2.

  1. "Cyclamen Red" colors based on a macrocyclic anthocyanin in carnation flowers.

    Science.gov (United States)

    Gonnet, J F; Fenet, B

    2000-01-01

    The "cyclamen" red (or pink) colors in carnation flowers-cultivars Red Rox and eight others-are based on the presence of a new macrocyclic anthocyanin, pelargonidin 3,5-di-O-beta-glucoside(6' ', 6' "-malyl diester) identified by spectroscopic methods. The instability of the bridging malyl group with sugars in acidic medium readily causes the formation of the opened ring form, 3-O-(6' '-O-malylglucoside)-5-O-glucoside. The issue of cyclamen colors based in carnations on this original acylated pelargonidin derivative simulating those based on simpler cyanidin glycosides in Rosa cultivars is discussed using CIELAB colorimetric coordinates.

  2. Catalytic Hydrolysis of Phosphate Diester with Metal Complexesof Macrocyclic Tetraamine in Comicellar Solution

    Institute of Scientific and Technical Information of China (English)

    XIANG Qing-Xiang; YU Xiao-Qi; YOU Jing-Song; YAN Qian-Shun; XIE Ru-Gang

    2001-01-01

    Four novel pyridine or benzene ring-containing pendant macrocyclic dioxotetraanines 2,6-dioxo-1,4,7,10-tetraazacy-clododeane ligands have been synthesized.Their metal com-plexes have been investigated as catalysts for the hydrolysis of bis(p-nitrophenyl) phosphate (BNPP) in aqueous comicellar solution.The results indicate that the hydrophobic interaction between substrate and metal complex, the nature of transition metal ion, and the micellar microenvironment are important factors for the hydrolysis, of BNPP.Large rate enhancement (up to over two-three orders magnitude) employing 5 hasbeen observed.

  3. Neighbor-directed histidine N(τ) alkylation. A route to imidazolium-containing phosphopeptide macrocycles

    Energy Technology Data Exchange (ETDEWEB)

    Qian, Wen-Jian [National Cancer Inst., Frederick, MD (United States); Park, Jung-Eun [National Cancer Inst., Bethesda, MD (United States); Grant, Robert [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Lai, Christopher C. [National Cancer Inst., Frederick, MD (United States); Kelley, James A. [National Cancer Inst., Frederick, MD (United States); Yaffe, Michael B. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Lee, Kyung S. [National Cancer Inst., Bethesda, MD (United States); Burke, Terrence R. [National Cancer Inst., Frederick, MD (United States)

    2015-07-07

    Our recently discovered, selective, on-resin route to N(τ)-alkylated imidazolium-containing histidine residues affords new strategies for peptide mimetic design. In this, we demonstrate the use of this chemistry to prepare a series of macrocyclic phosphopeptides, in which imidazolium groups serve as ring-forming junctions. These cationic moieties subsequently serve to charge-mask the phosphoamino acid group that directed their formation. Furthermore, neighbor-directed histidine N(τ)-alkylation opens the door to new families of phosphopeptidomimetics for use in a range of chemical biology contexts.

  4. Molecular Rearrangement of an Aza-Scorpiand Macrocycle Induced by pH: A Computational Study

    Directory of Open Access Journals (Sweden)

    Jesus Vicente De Julián-Ortiz

    2016-07-01

    Full Text Available Rearrangements and their control are a hot topic in supramolecular chemistry due to the possibilities that these phenomena open in the design of synthetic receptors and molecular machines. Macrocycle aza-scorpiands constitute an interesting system that can reorganize their spatial structure depending on pH variations or the presence of metal cations. In this study, the relative stabilities of these conformations were predicted computationally by semi-empirical and density functional theory approximations, and the reorganization from closed to open conformations was simulated by using the Monte Carlo multiple minimum method.

  5. STUDY ON THE SYNTHESIS OF POLYSTYRENE SUPPORTED MACROCYCLIC MERCAPTAL CHELATING RESIN AND ITS PROPERTIES

    Institute of Scientific and Technical Information of China (English)

    SUN Qiang; ZHANG Jinlan; XU Jiping

    1984-01-01

    Chelating resin with macrocyclic mercaptal group supported on macroporous polystyrene beads was synthesized, which showed good selectivity to Hg2+: its complexing capacity amounted to 30-60 mg Hg2+/g resin, two orders of magnitude greater than for other metal ions such as Ca2+, Zn2+,Cd2+, Pb2+ etc. This resin could restore the activity of urease which had been deactivated by poisoning with Hg2+. Its restoring power was far better than that of the mercapto-resin and common anionic exchange resins. It showed some promising use as an oral polymeric detoxifying drug for mercury poisoning.

  6. Carbohydrate-based aza-macrocycles by Richman-Atkins cyclization of glucopyranose precursors.

    Science.gov (United States)

    Rathjens, Andreas; Thiem, Joachim

    2017-01-13

    2, 3-Di-ω-halo- as well as 2, 3-di-ω-toluenesulfonamide-alkylated glucopyranoside derivatives were prepared. Their condensation with α,ω-bis-toluenesulfonamide components under varying Richman-Atkins conditions with alkali carbonate in DMF led to carbohydrate-linked aza-macrocycles displaying 14-, 17-, 18-, 21-, 24-, and 25-membered ring structures. Isomeric aza-macrocylic coronands of 20- as well as 30-membered ring size containing two saccharides could be obtained employing Richman-Atkins condensations of two functionalized sugar building units.

  7. Kinetics of oxidation of nickel(II) aza macrocycles by peroxydisulphate in aqueous media

    Indian Academy of Sciences (India)

    J Lalitham; V R Vijayaraghavan

    2000-10-01

    The kinetics of the oxidation of nickel (II) hexaaza and nickel (II) pentaaza macrocycles by the peroxydisulphate anion, S2O8 2-, were studied in aqueous media. Effect of H on reaction rate was also studied. The rate increases with increase of S2OO8 2- concentration. Rates are almost independent of acid between H 4 and 2, giving overall a relatively simple second-order rate law followed by oxidation within the ion pair solvent shell. Using rate = +1/2 d[Ni(L)3+]/dt = k[Ni(L)2+][S2O8 2-], oxidation rate constants were determined.

  8. Synthesis and P1' SAR exploration of potent macrocyclic tissue factor-factor VIIa inhibitors

    Energy Technology Data Exchange (ETDEWEB)

    Ladziata, Vladimir (Uladzimir); Glunz, Peter W.; Zou†, Yan; Zhang, Xiaojun; Jiang, Wen; Jacutin-Porte, Swanee; Cheney, Daniel L.; Wei, Anzhi; Luettgen, Joseph M.; Harper, Timothy M.; Wong, Pancras C.; Seiffert, Dietmar; Wexler, Ruth R.; Priestley, E. Scott (BMS)

    2016-10-01

    Selective tissue factor-factor VIIa complex (TF-FVIIa) inhibitors are viewed as promising compounds for treating thrombotic disease. In this contribution, we describe multifaceted exploratory SAR studies of S1'-binding moieties within a macrocyclic chemotype aimed at replacing cyclopropyl sulfone P1' group. Over the course of the optimization efforts, the 1-(1H-tetrazol-5-yl)cyclopropane P1' substituent emerged as an improved alternative, offering increased metabolic stability and lower clearance, while maintaining excellent potency and selectivity.

  9. New macrocyclic compounds using organotin complexes as intermediates: synthesis and characterization

    Directory of Open Access Journals (Sweden)

    Harminder Kaur

    2012-06-01

    Full Text Available Background & Aim:A new series of macrocyclic compounds 1-4 have been synthesized using tin as templates.Method:Tin templates are formed by refluxing the solution of dibutyltin (IV oxide with orthophenylenediamine (L1H,4-chlorocatechol (L2H, butane dithiol (L3H and 3-carboxypropyldisulphide (L4H. Results:The reaction is visualizedby cleavage X-Sn-X (X= oxygen/ nitrogen/ sulphur atom bond of tin template when treated withadipoyldichloride. Conclusion:The compounds 1-4 are characterized with the aid of elemental analyses, IR and NMR(1H, 13C studies which confirmed their proposed framework.

  10. Application of Calixarenes as Macrocyclic Ligands for Uranium(VI: A Review

    Directory of Open Access Journals (Sweden)

    Katarzyna Kiegiel

    2013-01-01

    Full Text Available Calixarenes represent a well-known family of macrocyclic molecules with broad range of potential applications in chemical, analytical, and engineering materials fields. This paper covers the use of calixarenes as complexing agents for uranium(VI. The high effectiveness of calix[6]arenes in comparison to other calixarenes in uranium(VI separation process is also presented. Processes such as liquid-liquid extraction (LLE, liquid membrane (LM separation, and ion exchange are considered as potential fields for application of calixarenes as useful agents for binding UO22+ for effective separation from aqueous solutions containing other metal components.

  11. Synthesis and antituberculosis activity of novel unfolded and macrocyclic derivatives of ent-kaurane steviol.

    Science.gov (United States)

    Khaybullin, Ravil N; Strobykina, Irina Yu; Dobrynin, Alexey B; Gubaydullin, Aidar T; Chestnova, Regina V; Babaev, Vasiliy M; Kataev, Vladimir E

    2012-11-15

    New derivatives of steviol 1, the aglycone of the glycosides of Stevia rebaudiana, including a novel class of semisynthetic diterpenoids, namely macrocyclic ent-kauranes were synthesized. These compounds possess antituberculosis activity inhibiting the in vitro growth of Mycobacterium Tuberculosis (H37R(V) strain) with MIC 5-20 μg/ml that is close to MIC 1 μg/ml demonstrated by antituberculosis drug isoniazid in control experiment. For the first time it was found that the change of ent-kaurane geometry (as in steviol 1) of tetracyclic diterpenoid skeleton to ent-beyerane one (as in isosteviol 2) influences on antituberculosis activity.

  12. Efficient macrocyclization of U-turn preorganized peptidomimetics: the role of intramolecular H-bond and solvophobic effects.

    Science.gov (United States)

    Becerril, Jorge; Bolte, Michael; Burguete, M Isabel; Galindo, Francisco; García-España, Enrique; Luis, Santiago V; Miravet, Juan F

    2003-06-04

    Simple peptidomimetic molecules derived from amino acids were reacted with meta- and para-bis(bromomethyl)benzene in acetonitrile to very efficiently yield macrocyclic structures. The cyclization reaction does not require high dilution techniques and seems to be insensitive to the size of the formed macrocycle. The analysis of data obtained by (1)H NMR, single-crystal X-ray diffraction, fluorescence measurements, and molecular mechanics indicate that folded conformations can preorganize the system for an efficient cyclization. The role played by intramolecular hydrogen-bonding and solvophobic effects in the presence of folded conformations is analyzed.

  13. Cyclooctane metathesis catalyzed by silica-supported tungsten pentamethyl [(ΞSiO)W(Me)5]: Distribution of macrocyclic alkanes

    KAUST Repository

    Riache, Nassima

    2014-10-03

    Metathesis of cyclic alkanes catalyzed by the new surface complex [(ΞSiO)W(Me)5] affords a wide distribution of cyclic and macrocyclic alkanes. The major products with the formula CnH2n are the result of either a ring contraction or ring expansion of cyclooctane leading to lower unsubstituted cyclic alkanes (5≤n≤7) and to an unprecedented distribution of unsubstituted macrocyclic alkanes (12≤n≤40), respectively, identified by GC/MS and by NMR spectroscopies.

  14. Logging residue bundling at the roadside in mountain operations

    Energy Technology Data Exchange (ETDEWEB)

    Spinelli, Raffaele; Magagnotti, Natascia (NR IVALSA, Sesto Fiorentino (Italy))

    2009-04-15

    The recovery of logging residue offers many benefits, and can be effectively performed with several techniques. This study presents the results of four distinct trials conducted on the Italian Alps with a truck-mounted bundler, and compares them with the figures obtained by the Austrian and German colleagues on the other side of the Alps. Average productivity varied between 14 and 22 bundles per productive machine hour (PMH), or between 10 and 15 bundles per scheduled machine hour (SMH). Mass production ranged from 3.1 to 4.3 oven-dry tonnes /SMH. If the machine is used for at least 800 SMH/year bundling costs will range between Euro 7 and 9/MWh, which is within the profitability limit indicated in Nordic studies. Although bundling may represent an additional cost in the slash-to-chip chain, it offers the important benefit of efficient outdoor winter storage, which is crucial in a region where the supply and demand of fuel biomass are often diachronic. The truck-mounted bundler used on the Alps adopts the same mechanism and achieves the same performance of the Nordic forwarder-mounted application. The main difference lies in its superior road mobility, which is crucial when covering scattered landings

  15. Dendritic bundles, minicolumns, columns, and cortical output units

    Directory of Open Access Journals (Sweden)

    Giorgio Innocenti

    2010-03-01

    Full Text Available The search for the fundamental building block of the cerebral cortex has highlighted three structures, perpendicular to the cortical surface: i columns of neurons with radially invariant response properties, e.g., receptive field position, sensory modality, stimulus orientation or direction, frequency tuning etc. ii minicolumns of radially aligned cell bodies and iii bundles, constituted by the apical dendrites of pyramidal neurons with cell bodies in different layers. The latter were described in detail, and sometimes quantitatively, in several species and areas. It was recently suggested that the dendritic bundles consist of apical dendrites belonging to neurons projecting their axons to specific targets. We review the concept above and suggest that another structural and computational unit of cerebral cortex is the cortical output unit (COU, i.e. an assembly of bundles of apical dendrites and their parent cell bodies including each of the outputs to distant cortical or subcortical structures, of a given cortical locus (area or part of an area. This somato-dendritic assembly receives inputs some of which are common to the whole assembly and determine its radially invariant response properties, others are specific to one or more dendritic bundles, and determine the specific response signature of neurons in the different cortical layers and projecting to different targets.

  16. Euler-Lagrange Forms and Cohomology Groups on Jet Bundles

    Institute of Scientific and Technical Information of China (English)

    CHEN Jing-Bo

    2005-01-01

    @@ Using the language of jet bundles, we generalize the definitions of Euler-Lagrange one-form and the associated cohomology which were introduced by Guo et al. [Commun. Theor. Phys. 37(2002)1]. Continuous and discreteLagrange mechanics and field theory are presented. Higher order Euler-Lagrange cohomology groups are also introduced.

  17. Get ready: Bundled payments are in your future.

    Science.gov (United States)

    2015-09-01

    The Centers for Medicare & Medicaid Services' (CMS') mandatory bundled payment pilot project makes clear that the agency intends to reform Medicare reimbursement. Hospitals in 75 geographic areas are required to participate in a five-year pilot project that puts them at risk for the cost of hip and knee replacements from the time of surgery until 90 days after discharge. Already, more than 6,500 providers are participating in the Bundled Payments for Care Improvement project, a voluntary program where participants can choose from 48 clinical episodes and four models. Even if they won't be part of a bundled payments arrangement, case managers need to shift their thinking to prepare for the future of reimbursement by developing close working relationships with post-acute providers, knowing the services and quality delivered by post-acute providers, and being aware of the costs for the entire episode of care. Case managers will not be able to handle all the responsibilities necessary in a bundled payment arrangement if they have large caseloads.

  18. Hair Cells: Bundles, Tuning, Transduction—A Moderated Discussion

    Science.gov (United States)

    Karavitaki, K. Domenica; Ricci, Anthony J.

    2011-11-01

    A discussion moderated by the authors on the topic "Hair Cells: Bundles, Tuning, Transduction" was held on 17 July 2011 at the 11th International Mechanics of Hearing Workshop in Williamstown, Massachusetts. The paper provides an edited transcript of the session.

  19. AdS 3-manifolds and Higgs bundles

    DEFF Research Database (Denmark)

    Alessandrini, Daniele; Li, Qiongling

    2015-01-01

    In this paper we investigate the relationships between closed AdS 3-manifolds and Higgs bundles. We have a new way to construct AdS structures that allows us to see many of their properties explicitly, for example we can recover the very recent formula by Tholozan for the volumes. We also find...

  20. Geometric Description of Fibre Bundle Surface for Birkhoff System

    Institute of Scientific and Technical Information of China (English)

    CAO Li-Mei; SUN Hua-Fei; ZHANG Zhen-Ning

    2009-01-01

    A fibre bundle surface for the BirkhofT system is constructed.The metric and the Riemannian connection of the surface are defined and the representation of the Gaussian curvature of this surface is presented.Finally,three examples for the Birkhoff system are given to illustrate our results.

  1. Self-adjointness of the Gaffney Laplacian on Vector Bundles

    Energy Technology Data Exchange (ETDEWEB)

    Bandara, Lashi, E-mail: lashi.bandara@chalmers.se [Chalmers University of Technology and University of Gothenburg, Mathematical Sciences (Sweden); Milatovic, Ognjen, E-mail: omilatov@unf.edu [University of North Florida, Department of Mathematics and Statistics (United States)

    2015-12-15

    We study the Gaffney Laplacian on a vector bundle equipped with a compatible metric and connection over a Riemannian manifold that is possibly geodesically incomplete. Under the hypothesis that the Cauchy boundary is polar, we demonstrate the self-adjointness of this Laplacian. Furthermore, we show that negligible boundary is a necessary and sufficient condition for the self-adjointness of this operator.

  2. Moduli of Parabolic Higgs Bundles and Atiyah Algebroids

    DEFF Research Database (Denmark)

    Logares, Marina; Martens, Johan

    2010-01-01

    . By considering the case of full flags, we get a Grothendieck–Springer resolution for all other flag types, in particular for the moduli spaces of twisted Higgs bundles, as studied by Markman and Bottacin and used in the recent work of Laumon–Ngô. We discuss the Hitchin system, and demonstrate that all...

  3. Heat transfer from a tube bundle in a bubble column

    Energy Technology Data Exchange (ETDEWEB)

    Saxena, S.C.; Vadivel, R.

    1988-09-01

    Heat transfer coefficient for an immersed five tube bundle in a two-phase (air-water) bubble column is measured as a function of air velocity and other relevant parameters. Average and local air holdup are also measured under identical conditions to characterize the system uniquely.

  4. Chest drain care bundle: Improving documentation and safety.

    Science.gov (United States)

    Hutton, Joe; Graham, Selina

    2015-01-01

    Chest drain insertion is a common advanced procedure with a significant associated risk of pain, distress, and complications. Nationally, audit and recommendations from leading bodies have highlighted a number of safety concerns around chest drain insertion. Audit work has demonstrated poor levels of documentation; particularly around use of premedication, use of ultrasound guidance and consent. This has obvious potential consequences for patient safety and thus is an important target for improvement work. This project quantifies current standards of documentation and aims to improve this through a combination of accessible and easy to read guidelines, education, and the introduction of a chest drain insertion bundle. National best practice standards were identified through review of national guidance. Drain insertion was prospectively analysed over a three month period to establish baseline standards of documentation. This initial work was presented and a bundle and clinical guidelines produced. Chest drain insertion was then reaudited and assessed for improvement. Results demonstrated an improvement in many areas of documentation, pushing local results above the national average. However, only 40% of cases used the new bundle due to a mixture of staff rotation and an unexpectedly high proportion of drains inserted in non targeted areas including the emergency department, theatre, and intensive care. Despite this, the introduction of accessible guidance and bundle has significantly improved chest drain insertion documentation to the benefit of all.

  5. Formation and Dissociation of Sperm Bundles in Monotremes.

    Science.gov (United States)

    Nixon, Brett; Ecroyd, Heath; Dacheux, Jean-Louis; Dacheux, Francoise; Labas, Valerie; Johnston, Steve D; Jones, Russell C

    2016-10-01

    Because monotremes are the earliest offshoot of the mammalian lineage, the platypus and short-beaked echidna were studied as model animals to assess the origin and biological significance of adaptations considered unique to therian mammals: epididymal sperm maturation and subsequent capacitation. We show that spermatozoa from both species assemble into bundles of approximately 100 cells during passage through the epididymis and that an epididymal protein-secreted protein, acidic, cysteine-rich (osteonectin; SPARC)-is involved in bundle formation. The bundles persisted during incubation in vitro for at least 1 h under conditions that capacitate therian spermatozoa, and then underwent a time-dependent dissociation to release spermatozoa capable of fertilization. Only after this dissociation could the spermatozoa bind to the perivitelline membrane of a hen's egg, display an altered form of motility reminiscent of hyperactivation, and be induced to undergo an acrosome reaction. It is concluded that the development of sperm bundles in the monotreme epididymis mandates that they require a time-dependent process to be capable of fertilizing an ovum. However, because this functional end point was achieved without overt changes in protein tyrosine phosphorylation (a hallmark of capacitation in therians), it is concluded that the process in monotremes is distinctly different from capacitation in therian mammals. © 2016 by the Society for the Study of Reproduction, Inc.

  6. MYOCARDIAL DEFORMATION AND COMPLETE LEFT BUNDLE BRANCH BLOCK

    Directory of Open Access Journals (Sweden)

    E. N. Pavlyukova

    2015-12-01

    Full Text Available Tissue Doppler imaging is evolving as a useful echocardiographic tool for quantitative assessment of left ventricular systolic and diastolic function. Over the last 10 years, myocardial deformation imaging has become possible initially with tissue Doppler , and more recently with myocardial speckle-tracking using 2D echocardiography. Unlike simple tissue velocity measurements, deformation measurements are specific for the region of interest. Strain rate or strain measurements have been used as sensitive indicators for subclinical diseases, and it is the most widely used tool to assess mechanical dyssynchrony. Left bundle branch block is a frequent, etiologically heterogeneous, clinically hostile and diagnostically challenging entity. About 2% of patients underwent cardiac stress testing show stable or intermittent left bundle branch block. Presence of left bundle branch block is associated with a lower and slower diastolic coronary flow velocity especially during hyperemia. Stress echocardiography is the best option for the diagnosis of ischemic heart disease, albeit specificity and sensitivity reduce in patients with left bundle branch block in the territory of left anterior descending artery in presence of initial septum dyskinesia.

  7. The Roach muscle bundle and umbilical cord coiling

    NARCIS (Netherlands)

    de Laat, Monique W. M.; Nikkels, Peter G. J.; Franx, Arie; Visser, Gerard H. A.

    2007-01-01

    Objective: To determine if presence of the Roach muscle, a small muscle bundle tying just beside the umbilical artery, contributes to umbilical cord coiling. Methods: 251 umbilical cords were examined. The umbilical coiling index (UCI) was calculated as the number of coils divided by the cord length

  8. Thermal conversion of bundled carbon nanotubes into graphitic ribbons.

    Science.gov (United States)

    Gutiérrez, H R; Kim, U J; Kim, J P; Eklund, P C

    2005-11-01

    High temperature heat treatment (HTT) of bundled single-walled carbon nanotubes (SWNTs) in vacuum ( approximately 10(-5) Torr) has been found to lead to the formation of two types of graphitic nanoribbons (GNRs), as observed by high-resolution transmission electron microscopy. Purified SWNT bundles were first found to follow two evolutionary steps, as reported previously, that is, tube coalescence (HTT approximately 1400 degrees C) and then massive bond rearrangement (HTT approximately 1600 degrees C), leading to the formation of bundled multiwall nanotubes (MWNTs) with 3-12 shells. At HTT > 1800 degrees C, we find that these MWNTs collapse into multishell GNRs. The first type of GNR we observed is driven by the collapse of diameter-doubled single-wall nanotubes, and their production is terminated at HTT approximately 1600 degrees C when the MWNTs also start to form. We propose that the collapse is driven by van der Waals forces between adjacent tubes in the same bundle. For HTT > 2000 degrees C, the heat-treated material is found to be almost completely in the multishell GNR form.

  9. On $(k,l)$-stable vector bundles over algebraic curves

    CERN Document Server

    Mata-Gutiérrez, Osbaldo

    2012-01-01

    In this paper, we study the $(k,l)$-stable vector bundles over non-singular projective curve $X$ of genus $g\\geq 2,$ its relation with stability and Segre invariants. For rank 2 and 3, we give an explicit description and relation of $(k,l)$-stability and Brill-Noether loci.

  10. Almost Lie structures on an anchored Banach bundle

    CERN Document Server

    Cabau, Patrick

    2011-01-01

    Under appropriate assumptions, we generalize the concept of linear almost Poisson struc- tures, almost Lie algebroids, almost differentials in the framework of Banach anchored bundles and the relation between these objects. We then obtain an adapted formalism for mechanical systems which is illustrated by the evolutionary problem of the "Hilbert snake"

  11. Frame-independent mechanics:geometry on affine bundles

    OpenAIRE

    Grabowska, K.; Grabowski, J.; Urbanski, P.

    2005-01-01

    Main ideas of the differential geometry on affine bundles are presented. Affine counterparts of Lie algebroid and Poisson structures are introduced and discussed. The developed concepts are applied in a frame-independent formulation of the time-dependent and the Newtonian mechanics.

  12. Fission yeast Scp3 potentially maintains microtubule orientation through bundling.

    Directory of Open Access Journals (Sweden)

    Kanako Ozaki

    Full Text Available Microtubules play important roles in organelle transport, the maintenance of cell polarity and chromosome segregation and generally form bundles during these processes. The fission yeast gene scp3+ was identified as a multicopy suppressor of the cps3-81 mutant, which is hypersensitive to isopropyl N-3-chlorophenylcarbamate (CIPC, a poison that induces abnormal multipolar spindle formation in higher eukaryotes. In this study, we investigated the function of Scp3 along with the effect of CIPC in the fission yeast Schizosaccharomyces pombe. Microscopic observation revealed that treatment with CIPC, cps3-81 mutation and scp3+ gene deletion disturbed the orientation of microtubules in interphase cells. Overexpression of scp3+ suppressed the abnormal orientation of microtubules by promoting bundling. Functional analysis suggested that Scp3 functions independently from Ase1, a protein largely required for the bundling of the mitotic spindle. A strain lacking the ase1+ gene was more sensitive to CIPC, with the drug affecting the integrity of the mitotic spindle, indicating that CIPC has a mitotic target that has a role redundant with Ase1. These results suggested that multiple systems are independently involved to ensure microtubule orientation by bundling in fission yeast.

  13. Bohr--Sommerfeld Lagrangians of moduli spaces of Higgs bundles

    DEFF Research Database (Denmark)

    Biswas, Indranil; Gammelgaard, Niels Leth; Logares, Marina

    Let $X$ be a compact connected Riemann surface of genus at least two. Let $M_H(r,d)$ denote the moduli space of semistable Higgs bundles on $X$ of rank $r$ and degree $d$. We prove that the compact complex Bohr-Sommerfeld Lagrangians of $M_H(r,d)$ are precisely the irreducible components of the n...

  14. Multicell slug flow heat transfer analysis of finite LMFBR bundles

    Energy Technology Data Exchange (ETDEWEB)

    Yeung, M.K.; Wolf, L.

    1978-12-01

    An analytical two-dimensional, multi-region, multi-cell technique has been developed for the thermal analysis of LMFBR rod bundles. Local temperature fields of various unit cells were obtained for 7, 19, and 37-rod bundles of different geometries and power distributions. The validity of the technique has been verified by its excellent agreement with the THTB calculational result. By comparing the calculated fully-developed circumferential clad temperature distribution with those of the experimental measurements, an axial correction factor has been derived to account for the entrance effect for practical considerations. Moreover, the knowledge of the local temperature field of the rod bundle leads to the determination of the effective mixing lengths L/sub ij/ for adjacent subchannels of various geometries. It was shown that the implementation of the accurately determined L/sub ij/ into COBRA-IIIC calculations has fairly significant effects on intersubchannel mixing. In addition, a scheme has been proposed to couple the 2-D distributed and lumped parameter calculation by COBRA-IIIC such that the entrance effect can be implanted into the distributed parameter analysis. The technique has demonstrated its applicability for a 7-rod bundle and the results of calculation were compared to those of three-dimensional analyses and experimental measurements.

  15. Temperature response of bundle-sheath conductance in maize leaves

    NARCIS (Netherlands)

    Yin, Xinyou; Putten, Van Der Peter E.L.; Struik, Paul C.; Driever, Steven M.

    2016-01-01

    A small bundle-sheath conductance (g bs) is essential for the C4 CO2-concentrating mechanism to suppress photorespiration effectively. To predict the productivity of C4 crops accurately under global warming, it is necessary to examine whether and how g

  16. Negotiating over bundles and prices using aggregate knowledge

    NARCIS (Netherlands)

    Somefun, D.J.A.; Klos, T.B.; La Poutré, J.A.

    2004-01-01

    Combining two or more items and selling them as one good, a practice called bundling, can be a very effective strategy for reducing the costs of producing, marketing, and selling goods. In this paper, we consider a form of multi-issue negotiation where a shop negotiates both the contents and the pri

  17. A note on stochastic calculus in vector bundles

    CERN Document Server

    Catuogno, Pedro J; Ruffino, Paulo R

    2011-01-01

    The aim of these notes is to relate covariant stochastic integration in a vector bundle $E$ (as in Norris \\cite{Norris}) with the usual Stratonovich calculus via the connector $\\K:TE \\rightarrow E$ (cf. e.g. Paterson \\cite{Paterson} or Poor \\cite{Poor}) which carries the connection dependence.

  18. Exposure Control Using Adaptive Multi-Stage Item Bundles.

    Science.gov (United States)

    Luecht, Richard M.

    This paper presents a multistage adaptive testing test development paradigm that promises to handle content balancing and other test development needs, psychometric reliability concerns, and item exposure. The bundled multistage adaptive testing (BMAT) framework is a modification of the computer-adaptive sequential testing framework introduced by…

  19. Rigidity of Minimal Submanifolds with Flat Normal Bundle

    Indian Academy of Sciences (India)

    Hai-Ping Fu

    2010-09-01

    Let $M^n(n≥ 3)$ be an -dimensional complete immersed $\\frac{n-2}{n}$-superstable minimal submanifold in an $(n+p)$-dimensional Euclidean space $\\mathbb{R}^{n+p}$ with flat normal bundle. We prove that if the second fundamental form of satisfies some decay conditions, then is an affine plane or a catenoid in some Euclidean subspace.

  20. Chordee repair utilizing a novel technique ensuring neurovascular bundle preservation.

    Science.gov (United States)

    Dean, G E; Burno, D K; Zaontz, M R

    2000-03-01

    Penile chordee, with and without hypospadias, is amenable to surgical correction. The Nesbit technique of dorsal plication of the ventral tunica albuginea is effective in correcting most cases of corporal disproportion. A hazard with this approach is the potential inclusion of the dorsal neurovascular bundle, with resultant erectile and sensory dysfunction. We developed a simple technique using the Freer elevator to isolate the neurovascular bundle prior to plication. This ensures that no injury occurs to the neurovascular bundle during plication. Since 1994, 37 boys with chordee have been repaired using this approach. Their ages at the time of operation ranged from 5 months to 28 years (mean 9 months). Following standard degloving of the penis, an incision through Buck's fascia is made lateral and parallel to the neurovascular bundle at the maximum level of the chordee. A similar incision is carried out on the contralateral side. A 4-mm-wide Freer elevator is positioned under Buck's fascia while hugging the tunica albuginea. The Freer elevator slides across the midline to the contralateral side, separating Buck's fascia and underlying layers from the tunica albuginea. Following isolation of the bundle, each corporal body is plicated by creating a longitudinal incision through the tunica albuginea, which then is closed transversely with a 5-0 polydioxanone suture. Buck's fascia subsequently is closed with an absorbable suture following confirmation of chordee correction. No complications have been encountered during a mean follow-up of 21 months (range 5-51 months). No patients have required reoperation for persistent chordee. We developed a technique that elevates the neurovascular bundle prior to plication, thereby ensuring no injury to this structure. We have successfully used this modified Nesbit technique since 1994 and have had no complications. Utilization of the Freer elevator adds an estimated 5 minutes to chordee correction compared to a standard

  1. A comprehensive comparison on vibration and heat transfer of two elastic heat transfer tube bundles

    Institute of Scientific and Technical Information of China (English)

    闫柯; 葛培琪; 翟强

    2015-01-01

    Elastic heat transfer tube bundles are widely used in the field of flow-induced vibration heat transfer enhancement. Two types of mainly used tube bundles, the planar elastic tube bundle and the conical spiral tube bundle were comprehensively compared in the condition of the same shell side diameter. The natural mode characteristics, the effect of fluid−structure interaction, the stress distribution, the comprehensive heat transfer performance and the secondary fluid flow of the two elastic tube bundles were all concluded and compared. The results show that the natural frequency and the critical velocity of vibration buckling of the planar elastic tube bundle are larger than those of the conical spiral tube bundle, while the stress distribution and the comprehensive heat transfer performance of the conical spiral tube bundle are relatively better.

  2. Early Results of Anatomic Double Bundle Anterior Cruciate Ligament Reconstruction

    Directory of Open Access Journals (Sweden)

    Demet Pepele

    2014-03-01

    Full Text Available Aim: The goal in anterior cruciate ligament reconstruction (ACLR is to restore the normal anatomic structure and function of the knee. In the significant proportion of patients after the traditional single-bundle ACLR, complaints of instability still continue. Anatomic double bundle ACLR may provide normal kinematics in knees, much closer to the natural anatomy. The aim of this study is to clinically assess the early outcomes of our anatomical double bundle ACLR. Material and Method: In our clinic between June 2009 and March 2010, performed the anatomic double bundle ACLR with autogenous hamstring grafts 20 patients were evaluated prospectively with Cincinnati, IKDC and Lysholm scores and in clinically for muscle strength and with Cybex II dynamometer. Results: The mean follow-up is 17.8 months (13-21 months. Patients%u2019 scores of Cincinnati, IKDC and Lysholm were respectively, preoperative 18.1, 39.3 and 39.8, while the post-op increased to 27.2, 76.3 and 86.3. In their last check, 17 percent of the patients according to IKDC scores (85% A (excellent and B (good group and 3 patients took place as C (adequate group. The power measurements of quadriceps and hamstring muscle groups of patients who underwent surgery showed no significant difference compared with the intact knees. Discussion: Double-bundle ACL reconstruction is a satisfactory method. There is a need comparative, long-term studies in large numbers in order to determine improving clinical outcome, preventing degeneration and restoring the knee biomechanics better.

  3. Infinitesimal moduli of G2 holonomy manifolds with instanton bundles

    Science.gov (United States)

    de la Ossa, Xenia; Larfors, Magdalena; Svanes, Eirik E.

    2016-11-01

    We describe the infinitesimal moduli space of pairs ( Y, V) where Y is a manifold with G 2 holonomy, and V is a vector bundle on Y with an instanton connection. These structures arise in connection to the moduli space of heterotic string compactifications on compact and non-compact seven dimensional spaces, e.g. domain walls. Employing the canonical G 2 cohomology developed by Reyes-Carrión and Fernández and Ugarte, we show that the moduli space decomposes into the sum of the bundle moduli {H}_{{overset{ěe }{d}}_A}^1(Y,End(V)) plus the moduli of the G 2 structure preserving the instanton condition. The latter piece is contained in {H}_{overset{ěe }{d}θ}^1(Y,TY) , and is given by the kernel of a map overset{ěe }{F} which generalises the concept of the Atiyah map for holomorphic bundles on complex manifolds to the case at hand. In fact, the map overset{ěe }{F} is given in terms of the curvature of the bundle and maps {H}_{overset{ěe }{d}θ}^1(Y,TY) into {H}_{{overset{ěe }{d}}_A}^2(Y,End(V)) , and moreover can be used to define a cohomology on an extension bundle of TY by End( V). We comment further on the resemblance with the holomorphic Atiyah algebroid and connect the story to physics, in particular to heterotic compactifications on ( Y, V) when α' = 0.

  4. Response of Critical Speed to Different Macrocycle Phases during Linear Periodization on Young Swimmers

    Directory of Open Access Journals (Sweden)

    João Bartholomeu NETO

    2016-03-01

    Full Text Available Sport training programs to young swimmers have to aggregate different physical stimulus to collaborate with overall physical development, which can lead to reach best results in competitions. Linear periodization seems to be a powerful tool that allow the organization of these stimulus. However, this model has been not studied. Regarding physical capacities, aerobic fitness is inversely related with fatigue and exercise performance. Although aerobic capacity evaluation used to be expensive, critical speed (CS is easy and non - expensive tool capable to make this measurement. Thus, the aim of this study was evaluate the effects of linear periodization in CS on well - trained young swimmers. Sixteen athletes (age: 14.06  1.22 years, height: 163.52  10.99 cm, weight: 57.4  12.7 kg, body mass index: 21.24  37; 7 ♀, were underwent to a linear macrocycle training with 23 weeks divided in four mesocycles: general endurance (i.e., 4 weeks, specific endurance (i.e., 8 weeks, competitive (i.e., 7 weeks and taper (i.e., 4 weeks. Results showed significantly improve on CS after competitive and taper mesocycle phases, which was composed by higher training intensity in comparison with other macrocycle phases. Therefore, the results of the present study indicate a collaboration of mesocycle intensity on the cumulative effects of linear periodization in CS improve on young swimmers.

  5. Tiered analytics for purity assessment of macrocyclic peptides in drug discovery: Analytical consideration and method development.

    Science.gov (United States)

    Qian Cutrone, Jingfang Jenny; Huang, Xiaohua Stella; Kozlowski, Edward S; Bao, Ye; Wang, Yingzi; Poronsky, Christopher S; Drexler, Dieter M; Tymiak, Adrienne A

    2017-05-10

    Synthetic macrocyclic peptides with natural and unnatural amino acids have gained considerable attention from a number of pharmaceutical/biopharmaceutical companies in recent years as a promising approach to drug discovery, particularly for targets involving protein-protein or protein-peptide interactions. Analytical scientists charged with characterizing these leads face multiple challenges including dealing with a class of complex molecules with the potential for multiple isomers and variable charge states and no established standards for acceptable analytical characterization of materials used in drug discovery. In addition, due to the lack of intermediate purification during solid phase peptide synthesis, the final products usually contain a complex profile of impurities. In this paper, practical analytical strategies and methodologies were developed to address these challenges, including a tiered approach to assessing the purity of macrocyclic peptides at different stages of drug discovery. Our results also showed that successful progression and characterization of a new drug discovery modality benefited from active analytical engagement, focusing on fit-for-purpose analyses and leveraging a broad palette of analytical technologies and resources.

  6. Gold-catalyzed Synthesis of Pyridine Containing Macrocycles, Related to Porphyrin

    Institute of Scientific and Technical Information of China (English)

    DYKER,Gerald; LIU,Jian-Hui; MERZ,Klaus

    2004-01-01

    @@ Porphyrins are very important substances used in a wide range of model systems in many areas, such as biomimic chemistry and material science. This kind of macrocycle generally consists of 5-membered ring to form a cyclic extended aromatic network. Recently much work have been done concerning the modification of porphyrins core structures, and many kinds of analogues have been recorded. One of the important aspects was the research of the porphyrinogen ligand.These macrocycles bear functional resemblance to certain kind of polydentate ligand, and provide a variety of tri-dimensional binding cavities for metal ions. In addition, some other kinds of analogues have been recorded, involving the introduction of a CH unit to replace one of the nitrogen atoms. We also notice the fact that pyridine is a very effective ligand, and it can coordinate with many kinds of metals. Based on these observations, we would like to design and synthesize a new porphyrinogen (5) analogue containing a NNNN core, two of the N atoms from pyrrole and the other two N from pyridine. Such core modifications may alter the electronic structure of the ring and provide variable cavity for metal coordination.

  7. A supramolecular ruthenium macrocycle with high catalytic activity for water oxidation that mechanistically mimics photosystem II

    Science.gov (United States)

    Schulze, Marcus; Kunz, Valentin; Frischmann, Peter D.; Würthner, Frank

    2016-06-01

    Mimicking the ingenuity of nature and exploiting the billions of years over which natural selection has developed numerous effective biochemical conversions is one of the most successful strategies in a chemist's toolbox. However, an inability to replicate the elegance and efficiency of the oxygen-evolving complex of photosystem II (OEC-PSII) in its oxidation of water into O2 is a significant bottleneck in the development of a closed-loop sustainable energy cycle. Here, we present an artificial metallosupramolecular macrocycle that gathers three Ru(bda) centres (bda = 2,2‧-bipyridine-6,6‧-dicarboxylic acid) that catalyses water oxidation. The macrocyclic architecture accelerates the rate of water oxidation via a water nucleophilic attack mechanism, similar to the mechanism exhibited by OEC-PSII, and reaches remarkable catalytic turnover frequencies >100 s-1. Photo-driven water oxidation yields outstanding activity, even in the nM concentration regime, with a turnover number of >1,255 and turnover frequency of >13.1 s-1.

  8. Synthesis, characterization, and photoactivated DNA cleavage by copper (II)/cobalt (II) mediated macrocyclic complexes.

    Science.gov (United States)

    Naik, H R Prakash; Naik, H S Bhojya; Aravinda, T; Lamani, D S

    2010-01-01

    We report the synthesis of new photonuclease consisting of two Co(II)/Cu(II) complexes of macrocyclic fused quinoline. Metal complexes are [MLX(2)], type where M = Co(II) (5), Cu(II) (6), and X = Cl, and are well characterized by elemental analysis, Fourier transform infrared spectroscopy, (1)H-NMR and electronic spectra. We have shown that photocleavage of plasmid DNA is markedly enhanced when this ligand is irradiated in the presence of Cu(II), and more so than that of cobalt. The chemistry of ternary and binary Co(II) complexes showing efficient light induced (360 nm) DNA cleavage activity is summarized. The role of the metal in photoinduced DNA cleavage reactions is explored by designing complex molecules having macrocyclic structure. The mechanistic pathways are found to be concentration dependent on Co(II)/Cu(II) complexes and the photoexcitation energy photoredox chemistry. Highly effective DNA cleavage ability of 6 is attributed to the effective cooperation of the metal moiety.

  9. Potent macrocyclic inhibitors of insulin-regulated aminopeptidase (IRAP) by olefin ring-closing metathesis.

    Science.gov (United States)

    Andersson, Hanna; Demaegdt, Heidi; Johnsson, Anders; Vauquelin, Georges; Lindeberg, Gunnar; Hallberg, Mathias; Erdelyi, Mate; Karlen, Anders; Hallberg, Anders

    2011-06-01

    Macrocyclic analogues of angiotensin IV (Ang IV, Val(1)-Tyr(2)-Ile(3)-His(4)-Pro(5)-Phe(6)) targeting the insulin-regulated aminopeptidase (IRAP) have been designed, synthesized, and evaluated biologically. Replacement of His(4)-Pro(5)-Phe(6) by a 2-(aminomethyl)phenylacetic acid (AMPAA) moiety and of Val(1) and Ile(3) by amino acids bearing olefinic side chains followed by macrocyclization provided potent IRAP inhibitors. The impact of the ring size and the type (saturated versus unsaturated), configuration, and position of the carbon-carbon bridge was assessed. The ring size generally affects the potency more than the carbon-carbon bond characteristics. Replacing Tyr(2) by β(3)hTyr or Phe is accepted, while N-methylation of Tyr(2) is deleterious for activity. Removal of the carboxyl group in the C-terminal slightly reduced the potency. Inhibitors 7 (K(i) = 4.1 nM) and 19 (K(i) = 1.8 nM), both encompassing 14-membered ring systems connected to AMPAA, are 10-fold more potent than Ang IV and are also more selective over aminopeptidase N (AP-N). Both compounds displayed high stability against proteolysis by metallopeptidases.

  10. Does a water-training macrocycle really create imbalances in swimmers' shoulder rotator muscles?

    Science.gov (United States)

    Batalha, Nuno; Marmeleira, José; Garrido, Nuno; Silva, António J

    2015-01-01

    The continuous execution of swimming techniques may cause muscle imbalances in shoulder rotators leading to injury. However, there is a lack of published research studies on this topic. The aim of this study was to analyze the influence of a competitive swim period on the shoulder rotator-cuff balance in young swimmers. A randomized controlled pretest-posttest design was used, with two measurements performed during the first macrocycle of the swimming season (baseline and 16 weeks). Twenty-seven young male swimmers (experimental group) and 22 male students who were not involved in swim training (control group) with the same characteristics were evaluated. Peak torque of shoulder internal and external rotators was assessed. Concentric action at 1.04 rad s(-1) (3 repetitions) and 3.14 rad s(-1) (20 repetitions) was measured using an isokinetic dynamometer (Biodex System 3). External/internal rotators strength ratios were also obtained. For both protocols, there were significant training effects on internal rotator strength and external/internal rotator ratios (p ≤ .05). This trend was the same for both shoulders. Within-group analysis showed significant changes from baseline to 16 weeks for internal rotators strength and unilateral ratios of the experimental group. Swimmers' internal rotator strength levels increased significantly. In contrast, a significant decrease of the unilateral ratios was observed. Findings suggest that a competitive swim macrocycle leads to an increase in muscular imbalances in the shoulder rotators of young competitive swimmers. Swimming coaches should consider implementing a compensatory strength-training program.

  11. The ex vivo neurotoxic, myotoxic and cardiotoxic activity of cucurbituril-based macrocyclic drug delivery vehicles.

    Science.gov (United States)

    Oun, Rabbab; Floriano, Rafael S; Isaacs, Lyle; Rowan, Edward G; Wheate, Nial J

    2014-11-01

    The cucurbituril family of drug delivery vehicles have been examined for their tissue specific toxicity using ex vivo models. Cucurbit[6]uril (CB[6]), cucurbit[7]uril (CB[7]) and the linear cucurbituril-derivative Motor2 were examined for their neuro-, myo- and cardiotoxic activity and compared with β-cyclodextrin. The protective effect of drug encapsulation by CB[7] was also examined on the platinum-based anticancer drug cisplatin. The results show that none of the cucurbiturils have statistically measurable neurotoxicity as measured using mouse sciatic nerve compound action potential. Cucurbituril myotoxicity was measured by nerve-muscle force of contraction through chemical and electrical stimulation. Motor2 was found to display no myotoxicity, whereas both CB[6] and CB[7] showed myotoxic activity via a presynaptic effect. Finally, cardiotoxicity, which was measured by changes in the rate and force of right and left atria contraction, was observed for all three cucurbiturils. Free cisplatin displays neuro-, myo- and cardiotoxic activity, consistent with the side-effects seen in the clinic. Whilst CB[7] had no effect on the level of cisplatin's neurotoxic activity, drug encapsulation within the macrocycle had a marked reduction in both the drug's myo- and cardiotoxic activity. Overall the results are consistent with the relative lack of toxicity displayed by these macrocycles in whole animal acute systemic toxicity studies and indicate continued potential of cucurbiturils as drug delivery vehicles for the reduction of the side effects associated with platinum-based chemotherapy.

  12. Supramolecular polymers constructed from macrocycle-based host-guest molecular recognition motifs.

    Science.gov (United States)

    Dong, Shengyi; Zheng, Bo; Wang, Feng; Huang, Feihe

    2014-07-15

    /physical properties, including stimuli responsiveness, self-healing, and environmental adaptation. It has been reported that macrocycle-based supramolecular polymers can respond to pH change, photoirradition, anions, cations, temperature, and solvent. Macrocycle-based supramolecular polymers have been prepared in solution, in gel, and in the solid state. Furthermore, the solvent has a very important influence on the formation of these supramolecular polymers. Crown ether- and pillararene-based supramolecular polymers have mainly formed in organic solvents, such as chloroform, acetone, and acetonitrile, while cyclodextrin- and cucurbituril-based supramolecular polymerizations have been usually observed in aqueous solutions. For calixarenes, both organic solvents and water have been used as suitable media for supramolecular polymerization. With the development of supramolecular chemistry and polymer science, various methods, such as nuclear magnetic resonance spectroscopy, X-ray techniques, electron microscopies, and theoretical calculation and computer simulation, have been applied for characterizing supramolecular polymers. The fabrication of macrocycle-based supramolecular polymers has become a currently hot research topic. In this Account, we summarize recent results in the investigation of supramolecular polymers constructed from macrocycle-based host-guest molecular recognition motifs. These supramolecular polymers are classified based on the different macrocycles used in them. Their monomer design, structure control, stimuli-responsiveness, and applications in various areas are discussed, and future research directions are proposed. It is expected that the development of supramolecular polymers will not only change the way we live and work but also exert significant influence on scientific research.

  13. 78 FR 29139 - Medicare Program; Bundled Payments for Care Improvement Model 1 Open Period

    Science.gov (United States)

    2013-05-17

    ... participation in Model 1 of the Bundled Payments for Care Improvement initiative. DATES: Model 1 of the Bundled Payments for Care Improvement Deadline: Interested organizations must submit a Model 1 Open Period... regarding Model 1 of the Bundled Payments for Care Improvement initiative. For additional information...

  14. Ipomoeassin F, a new cytotoxic macrocyclic glycoresin from the leaves of Ipomoea squamosa from the Suriname rainforest.

    Science.gov (United States)

    Cao, Shugeng; Norris, Andrew; Wisse, Jan H; Miller, James S; Evans, Randy; Kingston, David G I

    2007-08-01

    A new cytotoxic macrocyclic glycoresin, ipomoeassin F (6), has been isolated from the leaves of Ipomoea squamosa. The structure was elucidated by the interpretation of spectral data. Compound 6 was strongly active in the A2780 (human ovarian cancer cell line) assay with an IC(50) value of 0.036 microM.

  15. Diverse organo-peptide macrocycles via a fast and catalyst-free oxime/intein-mediated dual ligation.

    Science.gov (United States)

    Satyanarayana, Maragani; Vitali, Francesca; Frost, John R; Fasan, Rudi

    2012-02-01

    Macrocyclic Organo-Peptide Hybrids (MOrPHs) can be prepared from genetically encoded polypeptides via a chemoselective and catalyst-free reaction between a trifunctional oxyamino/amino-thiol synthetic precursor and an intein-fusion protein incorporating a bioorthogonal keto group.

  16. Push-pull macrocycles: donor-acceptor compounds with paired linearly conjugated or cross-conjugated pathways.

    Science.gov (United States)

    Leu, Wade C W; Fritz, Amanda E; Digianantonio, Katherine M; Hartley, C Scott

    2012-03-01

    Two-dimensional π-systems are of current interest in the design of functional organic molecules, exhibiting unique behavior for applications in organic electronics, single-molecule devices, and sensing. Here we describe the synthesis and characterization of "push-pull macrocycles": electron-rich and electron-poor moieties linked by a pair of (matched) conjugated bridges. We have developed a two-component macrocyclization strategy that allows these structures to be synthesized with efficiencies comparable to acyclic donor-bridge-acceptor systems. Compounds with both cross-conjugated (m-phenylene) and linearly conjugated (2,5-thiophene) bridges have been prepared. As expected, the compounds undergo excitation to locally excited states followed by fluorescence from charge-transfer states. The m-phenylene-based systems exhibit slower charge-recombination rates presumably due to reduced electronic coupling through the cross-conjugated bridges. Interestingly, pairing the linearly conjugated 2,5-thiophene bridges also slows charge recombination. DFT calculations of frontier molecular orbitals show that the direct HOMO-LUMO transition is polarized orthogonal to the axis of charge transfer for these symmetrical macrocyclic architectures, reducing the electronic coupling. We believe the push-pull macrocycle design may be useful in engineering functional frontier molecular orbital symmetries.

  17. The role of macrocyclic ligands in the peroxo/superoxo nature of Ni-O2 biomimetic complexes.

    Science.gov (United States)

    Zapata-Rivera, Jhon; Caballol, Rosa; Calzado, Carmen J

    2012-06-15

    The impact of the macrocyclic ligand on the electronic structure of two LNi-O2 biomimetic adducts, [Ni(12-TMC)O2](+) (12-TMC = 1,4,7,10-tetramethyl-1,4,7,10-tetraazacyclododecane) and [Ni(14-TMC)O2](+) (14-TMC = 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane), has been inspected by means of difference-dedicated configuration interaction calculations and a valence bond reading of the wavefunction. The system containing the 12-membered macrocyclic ligand has been experimentally described as a side-on nickel(III)-peroxo complex, whereas the 14-membered one has been characterized as an end-on nickel(II)-superoxide. Our results put in evidence the relationship between the steric effect of the macrocyclic ligand, the O2 coordination mode and the charge transfer extent between the Ni center and the O2 molecule. The 12-membered macrocyclic ligand favors a side-on coordination, a most efficient overlap between Ni 3d and O2 π* orbitals and, consequently, a larger charge transfer from LNi fragment to O2 molecule. The analysis of the ground-state electronic structure shows an enhancement of the peroxide nature of the Ni-O2 interaction for [Ni(12-TMC)O2](+), although a dominant superoxide character is found for both systems.

  18. Isonitrile iron(II) complexes with chiral N2P2 macrocycles in the enantioselective transfer hydrogenation of ketones.

    Science.gov (United States)

    Bigler, Raphael; Mezzetti, Antonio

    2014-12-19

    Bis(isonitrile) iron(II) complexes bearing a C2-symmetric N2P2 macrocyclic ligand, which are easily prepared from the corresponding bis(acetonitrile) analogue, catalyze the asymmetric transfer hydrogenation (ATH) of a broad scope of ketones in excellent yields (up to 98%) and with high enantioselectivity (up to 91% ee).

  19. Azalomycin F4a 2-ethylpentyl ester, a new macrocyclic lactone, from mangrove actinomycete Streptomyces sp.211726

    Institute of Scientific and Technical Information of China (English)

    Gan Jun Yuan; Kui Hong; Hai Peng Lin; Jia Li

    2010-01-01

    Azalomycin F4a 2-ethylpentyl ester,a new 36-membered macrocyclic lactone antibiotic,was isolated from mangrove actinomycete Streptomyces sp.211726.Its structure was elucidated on the basis of spectroscopic data.The compound showed broad-spectrum antifungal activity and moderate cytotoxicity against human colon tumor cell HCT-116.

  20. ForceGen 3D structure and conformer generation: from small lead-like molecules to macrocyclic drugs

    Science.gov (United States)

    Cleves, Ann E.; Jain, Ajay N.

    2017-03-01

    We introduce the ForceGen method for 3D structure generation and conformer elaboration of drug-like small molecules. ForceGen is novel, avoiding use of distance geometry, molecular templates, or simulation-oriented stochastic sampling. The method is primarily driven by the molecular force field, implemented using an extension of MMFF94s and a partial charge estimator based on electronegativity-equalization. The force field is coupled to algorithms for direct sampling of realistic physical movements made by small molecules. Results are presented on a standard benchmark from the Cambridge Crystallographic Database of 480 drug-like small molecules, including full structure generation from SMILES strings. Reproduction of protein-bound crystallographic ligand poses is demonstrated on four carefully curated data sets: the ConfGen Set (667 ligands), the PINC cross-docking benchmark (1062 ligands), a large set of macrocyclic ligands (182 total with typical ring sizes of 12-23 atoms), and a commonly used benchmark for evaluating macrocycle conformer generation (30 ligands total). Results compare favorably to alternative methods, and performance on macrocyclic compounds approaches that observed on non-macrocycles while yielding a roughly 100-fold speed improvement over alternative MD-based methods with comparable performance.

  1. Efficient access to new chemical space through flow--construction of druglike macrocycles through copper-surface-catalyzed azide-alkyne cycloaddition reactions.

    Science.gov (United States)

    Bogdan, Andrew R; James, Keith

    2010-12-27

    A series of 12- to 22-membered macrocycles, with druglike functionality and properties, have been generated by using a simple and efficient copper-catalyzed azide-acetylene cycloaddition reaction, conducted in flow in high-temperature copper tubing, under environmentally friendly conditions. The triazole-containing macrocycles have been generated in up to 90 % yield in a 5 min reaction, without resorting to the high-dilution conditions typical of macrocyclization reactions. This approach represents a very efficient method for constructing this important class of molecules, in terms of yield, concentration, and environmental considerations.

  2. A Macrocyclic 1,4-Diketone Enables the Synthesis of a p-Phenylene Ring That Is More Strained than a Monomer Unit of [4]Cycloparaphenylene.

    Science.gov (United States)

    Mitra, Nirmal K; Corzo, Hector H; Merner, Bradley L

    2016-07-01

    The synthesis of a p-terphenyl-based macrocycle, containing a p-phenylene unit with 42.6 kcal/mol of strain energy (SE), is reported. The conversion of a macrocyclic 1,4-diketone to a highly strained arene system takes place over five synthetic steps, featuring iterative dehydrative reactions in the aromatization protocol. Spectroscopic data of the deformed benzenoid macrocycle are in excellent agreement with other homologues that have been reported, indicating that the central p-phenylene ring of 9 is aromatic.

  3. Kinetics and mechanism of the stepwise complex formation of Cu(II) with tren-centered tris-macrocycles.

    Science.gov (United States)

    Soibinet, Matthieu; Gusmeroli, Deborah; Siegfried, Liselotte; Kaden, Thomas A; Palivan, Cornelia; Schweiger, Arthur

    2005-06-21

    The stepwise complexation kinetics of Cu2+ with three tetratopic ligands L1, L2 and L3, tren-centred macrocycles with different bridges connecting the 14-membered macrocycles with the tren unit, have been measured by stopped-flow photodiode array techniques at 25 degrees C, I= 0.5 M (KNO3), and pH = 4.96. The reaction between the first Cu2+ and the ligand consists of several steps. In a rapid reaction Cu2+ first binds to the flexible and more reactive tren-unit. In this intermediate a translocation from the tren unit to the macrocyclic ring, which forms the thermodynamic more stable complex, takes place. This species can react further with a second Cu2+ to give a heterotopic dinuclear species with one Cu2+ bound by the tren-unit and the other coordinated by the macrocycle. A further translocation occurs to give the homoditopic species with two Cu2+ in the macrocycles. Finally a slow rearrangement of the dinuclear complex gives the final species. The rates of the translocation are dependent on the length and rigidity of the bridge, whereas the complexation rates with the tren unit are little affected by it. VIS spectra of the species obtained by fitting the kinetic results, EPR-spectra taken during the reaction, and ES mass spectra of the products confirm the proposed mechanism. The addition of a second, third and fourth equivalent of Cu2+ proceeds in an analogous way, but is complicated by the fact that we start and end with a mixture of species. These steps were evaluated in a qualitative way only.

  4. Delayed hydride cracking properties of the endplate resistance welds of CANDU fuel bundles

    Energy Technology Data Exchange (ETDEWEB)

    Shek, G.K.; Wasiluk, B.S., E-mail: Gordon.Shek@kinectrics.com [Kinectrics Inc., Toronto, Ontario (Canada); Freire-Canosa, J. [Nuclear Waste Management Organization, Toronto, Ontario (Canada); Lampman, T. [AMEC NSS, Toronto, Ontario (Canada)

    2010-07-01

    In order to assess the susceptibility of CANDU fuel bundles endplate resistance welds to Delayed Hydride Cracking (DHC) during long term dry storage, the threshold stress intensity factor (KIH) and crack velocity of DHC in endplate welds of three unirradiated fuel bundles were determined. The three bundles tested covered the 28-element and 37-element designs and two Canadian manufacturers. The range of KIH values and DHC velocities obtained from the endplate welds of the three bundles are consistent with previous results obtained from a 37-element bundle produced by one of the manufacturers. (author)

  5. Macrocyclic compound as ionophores in lead(Ⅱ)ion-selective electrodes with excellent response characteristics

    Institute of Scientific and Technical Information of China (English)

    HUANG MeiRong; MA XiaoLi; LI XinGui

    2008-01-01

    Macrocyclic compounds, such as crown ethers, azacrown ethers, thiacrown ethers, calixarenes and porphyrins, which act as ionophores in lead(Ⅱ) ion-selective electrodes, are systematically summarized based on the latest literatures. The molecular structure characteristics of the ionophores are general-ized. The modification regulations for the substituted ionophores are elaborated with the purpose ofimproving the response features of the lead(Ⅱ) ion-selective electrodes assembled by them. It is pointed out that the introduction of pendant moieties which contain soft base coordination centers like N, S and P atoms is in favor of adjusting the cavity size and conformation of the macrocyclic com-pounds. Furthermore, there is synergic effect between the cavity and the donor sites of the ligand and thus the selective complexation of lead ions is easily realized, resulting in significant avoidance of the interference from other metal ions. The macrocyclic ionophore having the best response characteris-tics thus far was found to be N,N'-dimethylcyanodiaza-18-crown-6 with the detection limit of 7.0×10-8 (14.5 μg/L), which is one of the uncommon ionophores that can really eliminate the interference from silver and mercury ions. The selectivity coefficients of the ionophore for lead ions over other metal ions, such as alkali, alkaline earth and transition metal ions are in the order of 10-4 or smaller, where the se-lectivity coefficient of lead(Ⅱ) over mercury(Ⅱ) ions is much lower, down to 8.9×10-4. The structure de-sign idea for high-performance ionophore is proposed according to present results. The incorporation of nitrogen atom, especially cyano group or thiocyano group or amino/imino groups, rather than thio atom alone could result in new excellent lead ionophores. The aborative design for metacyclophanes containing aromatic nitrogen atoms with the aim of creating excellent ionophores would also become a potential research trend. The lead(Ⅱ) ion

  6. Catastrophic Failure and Critical Scaling Laws of Fiber Bundle Material

    Directory of Open Access Journals (Sweden)

    Shengwang Hao

    2017-05-01

    Full Text Available This paper presents a spring-fiber bundle model used to describe the failure process induced by energy release in heterogeneous materials. The conditions that induce catastrophic failure are determined by geometric conditions and energy equilibrium. It is revealed that the relative rates of deformation of, and damage to the fiber bundle with respect to the boundary controlling displacement ε0 exhibit universal power law behavior near the catastrophic point, with a critical exponent of −1/2. The proportion of the rate of response with respect to acceleration exhibits a linear relationship with increasing displacement in the vicinity of the catastrophic point. This allows for the prediction of catastrophic failure immediately prior to failure by extrapolating the trajectory of this relationship as it asymptotes to zero. Monte Carlo simulations are completed and these two critical scaling laws are confirmed.

  7. Infinitesimal moduli of G2 holonomy manifolds with instanton bundles

    CERN Document Server

    de la Ossa, Xenia; Svanes, Eirik Eik

    2016-01-01

    We describe the infinitesimal moduli space of pairs $(Y, V)$ where $Y$ is a manifold with $G_2$ holonomy, and $V$ is a vector bundle on $Y$ with an instanton connection. These structures arise in connection to the moduli space of heterotic string compactifications on compact and non-compact seven dimensional spaces, e.g. domain walls. Employing the canonical $G_2$ cohomology $H^*_{{\\check{\\rm d}}_E}(Y,E)$ developed by Reyes-Carri\\'on and Fern\\'andez and Ugarte, we show that the moduli space decomposes into the sum of the bundle moduli $H^1_{{\\check{\\rm d}}_A}(Y,{\\rm End}(V))$ plus the moduli of the $G_2$ structure preserving the instanton condition. The latter piece is contained in $H^1_{{\\check{\\rm d}}_\

  8. The special linear version of the projective bundle theorem

    CERN Document Server

    Ananyevskiy, Alexey

    2012-01-01

    A special linear Grassmann variety SGr(k,n) is the complement to the zero section of the determinant of the tautological vector bundle over Gr(k,n). For a representable ring cohomology theory A(-) with a special linear orientation and invertible stable Hopf map \\eta, including Witt groups and MSL[\\eta^{-1}], we have A(SGr(2,2n+1))=A(pt)[e]/(e^{2n}), and A(SGr(2,2n)) is a truncated polynomial algebra in two variables over A(pt). A splitting principle for such theories is established. We use the computations for the special linear Grassmann varieties to calculate A(BSL_n) in terms of the homogeneous power series in certain characteristic classes of the tautological bundle.

  9. Bohr--Sommerfeld Lagrangians of moduli spaces of Higgs bundles

    DEFF Research Database (Denmark)

    Biswas, Indranil; Gammelgaard, Niels Leth; Logares, Marina

    Let $X$ be a compact connected Riemann surface of genus at least two. Let $M_H(r,d)$ denote the moduli space of semistable Higgs bundles on $X$ of rank $r$ and degree $d$. We prove that the compact complex Bohr-Sommerfeld Lagrangians of $M_H(r,d)$ are precisely the irreducible components of the n......Let $X$ be a compact connected Riemann surface of genus at least two. Let $M_H(r,d)$ denote the moduli space of semistable Higgs bundles on $X$ of rank $r$ and degree $d$. We prove that the compact complex Bohr-Sommerfeld Lagrangians of $M_H(r,d)$ are precisely the irreducible components...

  10. Analyses of bundle experiment data using MATRA-h

    Energy Technology Data Exchange (ETDEWEB)

    Lim, In Cheol; Chea, Hee Taek [Korea Atomic Energy Research Institute, Taejon (Korea)

    1998-06-01

    When the construction and operation license for HANARO was renewed in 1995, 25% of CHF penalty was imposed. The reason for this was that the validation work related to the CHF design calculation was not enough for the assurance of CHF margin. As a part of the works to recover this CHF penalty, MATRA-h was developed by implementing the new correlations for the heat transfer, CHF prediction, subcooled void to the MATRA-a, which is the modified version of COBRA-IV-I done by KAERI. Using MATRA-h, the subchannel analyses for the bundle experiment data were performed. The comparison of the code predictions with the experimental results, it was found that the code would give the conservative predictions as far as the CHF in the bundle geometry is concerned. (author). 12 refs., 25 figs., 16 tabs.

  11. Giambelli-type formula for subbundles of the tangent bundle

    CERN Document Server

    Kazarian, M E

    1996-01-01

    Let us consider a generic $n$-dimensional subbundle $\\CV$ of the tangent bundle $TM$ on some given manifold $M$. Given $\\CV$ one can define different degeneracy loci $\\Si_{\\bold r}(\\CV),\\;\\bold r=(r_1\\leq r_2\\leq r_3 dimension of the subspace $\\CV^j(x)\\subset TM(x)$ spanned by all length $\\leq j$ commutators of vector fields tangent to $\\CV$ at $x$ is less than or equal to $r_j$. We calculate 'explicitly' the cohomology classes dual to $\\Si_{\\bold r}(\\CV)$ using determinantal formulas due to W.~Fulton and the expression for the Chern classes of the associated bundle of free Lie algebras in terms of the Chern classes of $\\CV$.

  12. Implementing strategic bundles for infection prevention and management.

    Science.gov (United States)

    Kaier, K; Wilson, C; Hulscher, M; Wollersheim, H; Huis, A; Borg, M; Scicluna, E; Lambert, M-L; Palomar, M; Tacconelli, E; De Angelis, G; Schumacher, M; Wolkewitz, M; Kleissle, E-M; Frank, U

    2012-04-01

    Healthcare-associated infections (HAI) are considered to be the most frequent adverse event in healthcare delivery. Active efforts to curb HAI have increased across Europe thanks to the growing emphasis on patient safety and quality of care. Recently, there has been dramatic success in improving the quality of patient care by focusing on the implementation of a group or "bundle" of evidenced-based preventive practices to achieve a better outcome than when implemented individually. The project entitled IMPLEMENT is designed to spread and test knowledge on how to implement strategic bundles for infection prevention and management in a diverse sample of European hospitals. The general goal of this project is to provide evidence on how to decrease the incidence of HAI and to improve antibiotic use under routine conditions.

  13. Heat transfer in a bundle cooled with supercritical Freon-12

    Energy Technology Data Exchange (ETDEWEB)

    Peiman, W.; Milner, A.; Pascoe, C.; Patel, H.; Richards, G.; Pioro, I., E-mail: wargha.peiman@mycampus.uoit.ca, E-mail: igor.pioro@uoit.ca [Univ. of Ontario Inst. of Tech., Faculty of Energy Systems and Nuclear Science, Oshawa, Ontario (Canada)

    2010-07-01

    This paper focuses on analyzing experimental data on Freon-12 at a supercritical pressure of 4.65 MPa. Experiments were conducted at the Institute of Physics and Power Engineering in Russia. The test section consisted of a pressure tube, ceramic inserts, a hexagonal flow tube and a vertical 7-element bundle installed inside the flow tube. The seven elements of the bundle were made of stainless steel and had an outer diameter of 9.5 mm and a heated length of one meter. Bulk-fluid temperature of the coolant at the inlet and the outlet of the test section and the temperature profile of the central heated element were recorded using thermocouples. For comparison, bulk-fluid, and sheath temperature profiles were calculated using various correlations and results were compared with the experimental values. (author)

  14. Through silicon vias filled with planarized carbon nanotube bundles.

    Science.gov (United States)

    Wang, Teng; Jeppson, Kjell; Olofsson, Niklas; Campbell, Eleanor E B; Liu, Johan

    2009-12-02

    The feasibility of using carbon nanotube (CNT) bundles as the fillers of through silicon vias (TSVs) has been demonstrated. CNT bundles are synthesized directly inside TSVs by thermal chemical vapor deposition (TCVD). The growth of CNTs in vias is found to be highly dependent on the geometric dimensions and arrangement patterns of the vias at atmospheric pressure. The CNT-Si structure is planarized by a combined lapping and polishing process to achieve both a high removal rate and a fine surface finish. Electrical tests of the CNT TSVs have been performed and their electrical resistance was found to be in the few hundred ohms range. The reasons for the high electrical resistance have been discussed and possible methods to decrease the electrical resistance have been proposed.

  15. Pressure effects on single wall carbon nanotube bundles

    Energy Technology Data Exchange (ETDEWEB)

    Teredesai, P.V. [Indian Inst. of Science, Bangalore (India). Dept. of Physics; Sood, A.K. [Indian Inst. of Science, Bangalore (India). Dept. of Physics; Chemistry and Physics of Materials Unit, Jawaharlal Nehru Center for Advanced Scientific Research, Jakkur Campus, Jakkur (India); Sharma, S.M.; Karmakar, S.; Sikka, S.K. [High Pressure Physics Div., Bhabha Atomic Research Center, Mumbai (India); Govindaraj, A.; Rao, C.N.R. [Chemistry and Physics of Materials Unit, Jawaharlal Nehru Center for Advanced Scientific Research, Jakkur Campus, Jakkur (India)

    2001-01-01

    We report high pressure Raman studies on single wall carbon nanotube bundles under hydrostatic conditions using two different pressure transmitting media, alcohol mixture and pure water. The radial and tangential modes show a blue shift when SWNT bundle is immersed in the liquids at ambient pressures. The pressure dependence of the radial modes is the same in both liquids. However, the pressure derivatives d{omega}/dP of the tangential modes are slightly higher for the water medium. Raman results are compared with studies under non-hydrostatic conditions and with recent high-pressure X-ray studies. It is seen that the mode frequencies of the recovered sample after pressure cycling from 26 GPa are downshifted by {proportional_to}7-10 cm{sup -1} as compared to the starting sample. (orig.)

  16. Bundle adjustment with raw inertial observations in UAV applications

    Science.gov (United States)

    Cucci, Davide Antonio; Rehak, Martin; Skaloud, Jan

    2017-08-01

    It is well known that accurate aerial position and attitude control is beneficial for image orientation in airborne photogrammetry. The aerial control is traditionally obtained by Kalman filtering/smoothing inertial and GNSS observations prior to the bundle-adjustment. However, in Micro Aerial Vehicles this process may result in poor attitude determination due to the limited quality of the inertial sensors, large alignment uncertainty and residual correlations between sensor biases and initial attitude. We propose to include the raw inertial observations directly into the bundle-adjustment instead of as position and attitude weighted observations from a separate inertial/GNSS fusion step. The necessary observation models are derived in detail within the context of the so called ;Dynamic Networks;. We examine different real world cases and we show that the proposed approach is superior to the established processing pipeline in challenging scenarios such as mapping in corridors and in areas where the reception of GNSS signals is denied.

  17. An improved partial bundle method for linearly constrained minimax problems

    Directory of Open Access Journals (Sweden)

    Chunming Tang

    2016-02-01

    Full Text Available In this paper, we propose an improved partial bundle method for solving linearly constrained minimax problems. In order to reduce the number of component function evaluations, we utilize a partial cutting-planes model to substitute for the traditional one. At each iteration, only one quadratic programming subproblem needs to be solved to obtain a new trial point. An improved descent test criterion is introduced to simplify the algorithm. The method produces a sequence of feasible trial points, and ensures that the objective function is monotonically decreasing on the sequence of stability centers. Global convergence of the algorithm is established. Moreover, we utilize the subgradient aggregation strategy to control the size of the bundle and therefore overcome the difficulty of computation and storage. Finally, some preliminary numerical results show that the proposed method is effective.

  18. Curved Space-Times by Crystallization of Liquid Fiber Bundles

    Science.gov (United States)

    Hélein, Frédéric; Vey, Dimitri

    2017-01-01

    Motivated by the search for a Hamiltonian formulation of Einstein equations of gravity which depends in a minimal way on choices of coordinates, nor on a choice of gauge, we develop a multisymplectic formulation on the total space of the principal bundle of orthonormal frames on the 4-dimensional space-time. This leads quite naturally to a new theory which takes place on 10-dimensional manifolds. The fields are pairs of ((α ,ω ),π), where (α ,ω ) is a 1-form with coefficients in the Lie algebra of the Poincaré group and π is an 8-form with coefficients in the dual of this Lie algebra. The dynamical equations derive from a simple variational principle and imply that the 10-dimensional manifold looks locally like the total space of a fiber bundle over a 4-dimensional base manifold. Moreover this base manifold inherits a metric and a connection which are solutions of a system of Einstein-Cartan equations.

  19. Frobenius Pull Backs of Vector Bundles in Higher Dimensions

    Indian Academy of Sciences (India)

    V Trivedi

    2012-11-01

    We prove that for a smooth projective variety of arbitrary dimension and for a vector bundle over , the Harder–Narasimhan filtration of a Frobenius pull back of is a refinement of the Frobenius pull back of the Harder–Narasimhan filtration of , provided there is a lower bound on the characteristic (in terms of rank of and the slope of the destabilizing sheaf of the cotangent bundle of ). We also recall some examples, due to Raynaud and Monsky, to show that some lower bound on is necessary. We also give a bound on the instability degree of the Frobenius pull back of in terms of the instability degree of and well defined invariants of .

  20. Cofilin-mediated actin dynamics promotes actin bundle formation during Drosophila bristle development.

    Science.gov (United States)

    Wu, Jing; Wang, Heng; Guo, Xuan; Chen, Jiong

    2016-08-15

    The actin bundle is an array of linear actin filaments cross-linked by actin-bundling proteins, but its assembly and dynamics are not as well understood as those of the branched actin network. Here we used the Drosophila bristle as a model system to study actin bundle formation. We found that cofilin, a major actin disassembly factor of the branched actin network, promotes the formation and positioning of actin bundles in the developing bristles. Loss of function of cofilin or AIP1, a cofactor of cofilin, each resulted in increased F-actin levels and severe defects in actin bundle organization, with the defects from cofilin deficiency being more severe. Further analyses revealed that cofilin likely regulates actin bundle formation and positioning by the following means. First, cofilin promotes a large G-actin pool both locally and globally, likely ensuring rapid actin polymerization for bundle initiation and growth. Second, cofilin limits the size of a nonbundled actin-myosin network to regulate the positioning of actin bundles. Third, cofilin prevents incorrect assembly of branched and myosin-associated actin filament into bundles. Together these results demonstrate that the interaction between the dynamic dendritic actin network and the assembling actin bundles is critical for actin bundle formation and needs to be closely regulated.

  1. HYDRODISSECTION FOR PRESERVATION OF NEUROVASCULAR BUNDLE DURING RADICAL PROSTATECTOMY

    Directory of Open Access Journals (Sweden)

    H. S. Gevorgyan

    2016-01-01

    Full Text Available Nerve-sparing radical prostatectomy is one of the high-tech operations in urology, and the challenge of the surgeon is not only to remove the prostate tumor, but also to provide a high quality of life. The fact that most questions devoted from patients in a conversation with the surgeon before the operation are devoted to this issue, shows the importance and relevance. At present, the diagnostic methods allow significantly more likely to detect early  prostate cancer, making finding and treatment of these patients more affordable and allows to apply this operation.Lately, it seems urgent to explore the possibility of water jet dissection in the field of urology, in particular, for nerve-sparing prostatectomy. Preservation of erectile function depends largely on the quality of separating the neurovascular bundle. Standard use of electrocautery is associated with damage to the neurovascular bundle.  When performing operations using water-jet mobilization of prostate the selective dissection of tissue is performed. This avoids injury of neurovascular bundle and further postoperative complications. The use of this technique may allow the surgeon to provide a more accurate mobilization prostate and selectively controlled intersection vessels heading to the prostate from the neurovascular bundle, reduce intraoperative blood loss,  maintaining continence, erectile function.This literature review is considered by the experience of using nerve-sparing radical prostatectomy using a water-jet dissector, estimated intraoperative parameters using this method.However, we have the lack of extensive research capabilities of this technique when performing nerve-preserving radical prostatectomy, that does not allow to make a comprehensive presentation on the benefits of this technique and its effects on erectile function and quality of urination, further study of this issue in such a difficult category of patients.

  2. A review on saturated boiling of liquids on tube bundles

    Science.gov (United States)

    Swain, Abhilas; Das, Mihir Kumar

    2014-05-01

    A review of recent investigation on boiling of saturated liquids over plain and enhanced tube bundles has been carried out taking the earlier review works as reference point. The experimental observations of various geometry and performance parameters studied by researchers are analyzed keeping current demand of industries in design and development of compact, efficient heat exchanging devices. The study shows that tube spacing plays an important role in determination of compactness of the heat exchanger.

  3. Input modelling for subchannel analysis of CANFLEX fuel bundle

    Energy Technology Data Exchange (ETDEWEB)

    Park, Joo Hwan; Jun, Ji Su; Suk, Ho Chun [Korea Atomic Energy Research Institute, Taejon (Korea)

    1998-06-01

    This report describs the input modelling for subchannel analysis of CANFLEX fuel bundle using CASS(Candu thermalhydraulic Analysis by Subchannel approacheS) code which has been developed for subchannel analysis of CANDU fuel channel. CASS code can give the different calculation results according to users' input modelling. Hence, the objective of this report provide the background information of input modelling, the accuracy of input data and gives the confidence of calculation results. (author). 11 refs., 3 figs., 4 tabs.

  4. Prostaglandins temporally regulate cytoplasmic actin bundle formation during Drosophila oogenesis

    OpenAIRE

    Spracklen, Andrew J.; Kelpsch, Daniel J.; Chen, Xiang; Spracklen, Cassandra N.; Tootle, Tina L.

    2014-01-01

    Prostaglandins (PGs)—lipid signals produced downstream of cyclooxygenase (COX) enzymes—regulate actin dynamics in cell culture and platelets, but their roles during development are largely unknown. Here we define a new role for Pxt, the Drosophila COX-like enzyme, in regulating the actin cytoskeleton—temporal restriction of actin remodeling during oogenesis. PGs are required for actin filament bundle formation during stage 10B (S10B). In addition, loss of Pxt results in extensive early actin ...

  5. ETA INVARIANTS, DIFFERENTIAL CHARACTERS AND FLAT VECTOR BUNDLES

    Institute of Scientific and Technical Information of China (English)

    J.M.BISMUT

    2005-01-01

    The purpose of this paper is to give a refinement of the Atiyah-Singer families index theorem at the level of differential characters. Also a Riemann-Roch-Grothendieck theorem for the direct image of flat vector bundles by proper submersions is proved,with Chern classes with coefficients in C/Q. These results are much related to prior work of Gillet-Soule, Bismut-Lott and Lott.

  6. Double bundle posterior cruciate ligament reconstruction: surgical technique and results.

    Science.gov (United States)

    Fanelli, Gregory C; Beck, John D; Edson, Craig J

    2010-12-01

    The keys to successful posterior cruciate ligament reconstruction are to identify and treat all pathology, use strong graft material, accurately place tunnels in anatomic insertion sites, minimize graft bending, use a mechanical graft tensioning device, use primary and back-up graft fixation, and use the appropriate postoperative rehabilitation program. Adherence to these technical principles results in successful single and double-bundle arthroscopic transtibial tunnel posterior cruciate ligament reconstruction based upon stress radiography, arthrometer, knee ligament rating scales, and patient satisfaction measurements.

  7. Image processing for cameras with fiber bundle image relay.

    Science.gov (United States)

    Olivas, Stephen J; Arianpour, Ashkan; Stamenov, Igor; Morrison, Rick; Stack, Ron A; Johnson, Adam R; Agurok, Ilya P; Ford, Joseph E

    2015-02-10

    Some high-performance imaging systems generate a curved focal surface and so are incompatible with focal plane arrays fabricated by conventional silicon processing. One example is a monocentric lens, which forms a wide field-of-view high-resolution spherical image with a radius equal to the focal length. Optical fiber bundles have been used to couple between this focal surface and planar image sensors. However, such fiber-coupled imaging systems suffer from artifacts due to image sampling and incoherent light transfer by the fiber bundle as well as resampling by the focal plane, resulting in a fixed obscuration pattern. Here, we describe digital image processing techniques to improve image quality in a compact 126° field-of-view, 30 megapixel panoramic imager, where a 12 mm focal length F/1.35 lens made of concentric glass surfaces forms a spherical image surface, which is fiber-coupled to six discrete CMOS focal planes. We characterize the locally space-variant system impulse response at various stages: monocentric lens image formation onto the 2.5 μm pitch fiber bundle, image transfer by the fiber bundle, and sensing by a 1.75 μm pitch backside illuminated color focal plane. We demonstrate methods to mitigate moiré artifacts and local obscuration, correct for sphere to plane mapping distortion and vignetting, and stitch together the image data from discrete sensors into a single panorama. We compare processed images from the prototype to those taken with a 10× larger commercial camera with comparable field-of-view and light collection.

  8. The Business of Bundling: Joining Forces on Joint Replacement.

    Science.gov (United States)

    Kaldy, Joanne

    2016-03-01

    A mandated bundled-payment program for joint replacement is in place in several regions across the country, and practitioners such as pharmacists are still sorting out their roles in this federal initiative. To get involved, pharmacists need to establish connections with area hospitals and physician groups to promote and document their ability to manage medications, reduce and eliminate medication-related problems and rehospitalizations, and work with patients to maximize adherence and improve communication for those undergoing hip and knee replacement.

  9. "Bundle Data" Approach at GES DISC Targeting Natural Hazards

    Science.gov (United States)

    Shie, C. L.; Shen, S.; Kempler, S. J.

    2015-12-01

    Severe natural phenomena such as hurricane, volcano, blizzard, flood and drought have the potential to cause immeasurable property damages, great socioeconomic impact, and tragic loss of human life. From searching to assessing the "Big", i.e., massive and heterogeneous scientific data (particularly, satellite and model products) in order to investigate those natural hazards, it has, however, become a daunting task for Earth scientists and applications researchers, especially during recent decades. The NASA Goddard Earth Sciences Data and Information Service Center (GES DISC) has served "Big" Earth science data, and the pertinent valuable information and services to the aforementioned users of diverse communities for years. In order to help and guide our users to online readily (i.e., with a minimum effort) acquire their requested data from our enormous resource at GES DISC for studying their targeted hazard/event, we have thus initiated a "Bundle Data" approach in 2014, first targeting the hurricane event/topic. We have recently worked on new topics such as volcano and blizzard. The "bundle data" of a specific hazard/event is basically a sophisticated integrated data package consisting of a series of proper datasets containing a group of relevant ("knowledge-based") data variables readily accessible to users via a system-prearranged table linking those data variables to the proper datasets (URLs). This online approach has been developed by utilizing a few existing data services such as Mirador as search engine; Giovanni for visualization; and OPeNDAP for data access, etc. The online "Data Cookbook" site at GES DISC is the current host for the "bundle data". We are now also planning on developing an "Automated Virtual Collection Framework" that shall eventually accommodate the "bundle data", as well as further improve our management in "Big Data".

  10. Cerebrocerebellar system and Arnold's bundle: A tractographic study: preliminary results

    Directory of Open Access Journals (Sweden)

    Eliasz Engelhardt

    Full Text Available Abstract The cerebellum, traditionally considered a structure involved in balance and movement control, was more recently recognized as important in cognitive, emotional and behavioral functions. These functions appear to be related to the more recent parts of the cerebellum that belong to the cerebrocerebellar system. One of the key segments of this system is the (prefronto-[penduncule]-pontine projection that represents the Arnold's bundle. Diffusion tensor imaging and tractography (DTI-TR has permitted in vivo virtual dissection of white matter tracts, including those of the cerebellar. Objective: To study the fronto-[peduncule]-pontine projection (Arnold's bundle, with DTI-TR. Methods: Ten normal subjects were included (mean age 30 years. Standard acquisitions in three planes were obtained with a 1.5T GE Signa Horizon scanner, complemented with DTI acquisitions. Post-processing and analysis was performed using an ADW 4.3 workstation running Functool 4.5.3 (GE Medical Systems. A single ROI was placed on the medial third of the cerebral peduncle base, considered the site of convergence of the fibers of Arnold's bundle, bilaterally. Results: Twenty tractograms were obtained. All were constituted by a significant number of fibers in correspondence to the frontal lobe, and part of them anterior to the coronal plane at the anterior commissure, which characterizes them as associated to the prefrontal region. Conclusions: For the first time, frontal lobe related projections were systematically revealed with DTI-TR seeded from cerebral peduncle base ROIs. They showed anatomic coherence with Arnold's bundle, which includes the prefrontopontine segment of the cortico-ponto-cerebellar path, one of the components of the cerebrocerebellar system, acknowledged as fundamental for non-motor functions such as cognition, emotion and behavior.

  11. Topological Aharonov-Bohm Effect and Pseudo-Particle Bundles

    Science.gov (United States)

    Payandeh, Farrin

    2016-10-01

    Exploiting a topological approach, we discuss the outstanding Aharonov-Bohm effect and try to explain it in the context of the principal P(M, U(1)) bundle. We show that this could be done by excluding a specific region from the main manifold which acts as the solenoid around which the effect is observed. Moreover, we discuss the impacts of pseudo-particles in this topological approach.

  12. Bundle Data Approach at GES DISC Targeting Natural Hazards

    Science.gov (United States)

    Shie, Chung-Lin; Shen, Suhung; Kempler, Steven J.

    2015-01-01

    Severe natural phenomena such as hurricane, volcano, blizzard, flood and drought have the potential to cause immeasurable property damages, great socioeconomic impact, and tragic loss of human life. From searching to assessing the Big, i.e., massive and heterogeneous scientific data (particularly, satellite and model products) in order to investigate those natural hazards, it has, however, become a daunting task for Earth scientists and applications researchers, especially during recent decades. The NASA Goddard Earth Sciences Data and Information Service Center (GES DISC) has served Big Earth science data, and the pertinent valuable information and services to the aforementioned users of diverse communities for years. In order to help and guide our users to online readily (i.e., with a minimum effort) acquire their requested data from our enormous resource at GES DISC for studying their targeted hazard event, we have thus initiated a Bundle Data approach in 2014, first targeting the hurricane event topic. We have recently worked on new topics such as volcano and blizzard. The bundle data of a specific hazard event is basically a sophisticated integrated data package consisting of a series of proper datasets containing a group of relevant (knowledge--based) data variables readily accessible to users via a system-prearranged table linking those data variables to the proper datasets (URLs). This online approach has been developed by utilizing a few existing data services such as Mirador as search engine; Giovanni for visualization; and OPeNDAP for data access, etc. The online Data Cookbook site at GES DISC is the current host for the bundle data. We are now also planning on developing an Automated Virtual Collection Framework that shall eventually accommodate the bundle data, as well as further improve our management in Big Data.

  13. Analysis of Subchannel and Rod Bundle PSBT Experiments with CATHARE 3

    Directory of Open Access Journals (Sweden)

    M. Valette

    2012-01-01

    Full Text Available This paper presents the assessment of CATHARE 3 against PWR subchannel and rod bundle tests of the PSBT benchmark. Noticeable measurements were the following: void fraction in single subchannel and rod bundle, multiple liquid temperatures at subchannel exit in rod bundle, and DNB power and location in rod bundle. All these results were obtained both in steady and transient conditions. Void fraction values are satisfactory predicted by CATHARE 3 in single subchannels with the pipe module. More dispersed predictions of void values are obtained in rod bundles with the CATHARE 3 3D module at subchannel scale. Single-phase liquid mixing tests and DNB tests in rod bundle are also analyzed. After calibrating the mixing in liquid single phase with specific tests, DNB tests using void mixing give mitigated results, perhaps linked to inappropriate use of CHF lookup tables in such rod bundles with many spacers.

  14. Bagger-Witten line bundles on moduli spaces of elliptic curves

    CERN Document Server

    Gu, W

    2016-01-01

    In this paper we discuss Bagger-Witten line bundles over moduli spaces of SCFTs. We review how in general they are `fractional' line bundles, not honest line bundles, twisted on triple overlaps. We discuss the special case of moduli spaces of elliptic curves in detail. There, the Bagger-Witten line bundles does not exist as an ordinary line bundle, but rather is necessarily fractional. As a fractional line bundle, it is nontrivial (though torsion) over the uncompactified moduli stack, and its restriction to the interior, excising corners with enhanced stabilizers, is also fractional. We review and compare to results of recent work arguing that well-definedness of the worldsheet metric implies that the Bagger-Witten line bundle is torsion, and give general arguments on the existence of universal structures on moduli spaces of SCFTs, in which superconformal deformation parameters are promoted to nondynamical fields ranging over the SCFT moduli space.

  15. Mass Transport Through Carbon Nanotube-Polystyrene Bundles

    Science.gov (United States)

    Lin, Rongzhou; Tran, Tuan

    2016-05-01

    Carbon nanotubes have been widely used as test channels to study nanofluidic transport, which has been found to have distinctive properties compared to transport of fluids in macroscopic channels. A long-standing challenge in the study of mass transport through carbon nanotubes (CNTs) is the determination of flow enhancement. Various experimental investigations have been conducted to measure the flow rate through CNTs, mainly based on either vertically aligned CNT membranes or individual CNTs. Here, we proposed an alternative approach that can be used to quantify the mass transport through CNTs. This is a simple method relying on the use of carbon nanotube-polystyrene bundles, which are made of CNTs pulled out from a vertically aligned CNT array and glued together by polystyrene. We experimentally showed by using fluorescent tagging that the composite bundles allowed measureable and selective mass transport through CNTs. This type of composite bundle may be useful in various CNT research areas as they are simple to fabricate, less likely to form macroscopic cracks, and offer a high density of CNT pores while maintaining the aligned morphology of CNTs.

  16. Fabrication of CANFLEX bundle kit for irradiation test in NRU

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Moon Sung; Kwon, Hyuk Il; Ji, Chul Goo; Chang, Ho Il; Sim, Ki Seob; Suk, Ho Chun

    1997-10-01

    CANFLEX bundle kit was prepared at KAERI for the fabrication of complete bundle at AECL. Completed bundle will be used for irradiation test in NRU. Provisions in the `Quality Assurance Manual for HWR Fuel Projects,` `Manufacturing Plan` and `Quality Verification, Inspection and Test Plan` were implemented as appropriately for the preparation of CANFLEX kit. A set of CANFLEX kit consist of 43 fuel sheath of two different sizes with spacers, bearing pads and buttons attached, 2 pieces of end plates and 86 pieces of end caps with two different sizes. All the documents utilized as references for the fabrication such as drawings, specifications, operating instructions, QC instructions and supplier`s certificates are specified in this report. Especially, suppliers` certificates and inspection reports for the purchased material as well as KAERI`s inspection report are integrated as attachments to this report. Attached to this report are supplier`s certificates and KAERI inspection reports for the procured materials and KAERI QC inspection reports for tubes, pads, spacers, buttons, end caps, end plates and fuel sheath. (author). 37 refs.

  17. Conservation of helical bundle structure between the exocyst subunits.

    Directory of Open Access Journals (Sweden)

    Nicole J Croteau

    Full Text Available BACKGROUND: The exocyst is a large hetero-octomeric protein complex required for regulating the targeting and fusion of secretory vesicles to the plasma membrane in eukaryotic cells. Although the sequence identity between the eight different exocyst subunits is less than 10%, structures of domains of four of the subunits revealed a similar helical bundle topology. Characterization of several of these subunits has been hindered by lack of soluble protein for biochemical and structural studies. METHODOLOGY/PRINCIPAL FINDINGS: Using advanced hidden Markov models combined with secondary structure predictions, we detect significant sequence similarity between each of the exocyst subunits, indicating that they all contain helical bundle structures. We corroborate these remote homology predictions by identifying and purifying a predicted domain of yeast Sec10p, a previously insoluble exocyst subunit. This domain is soluble and folded with approximately 60% alpha-helicity, in agreement with our predictions, and capable of interacting with several known Sec10p binding partners. CONCLUSIONS/SIGNIFICANCE: Although all eight of the exocyst subunits had been suggested to be composed of similar helical bundles, this has now been validated by our hidden Markov model structure predictions. In addition, these predictions identified protein domains within the exocyst subunits, resulting in creation and characterization of a soluble, folded domain of Sec10p.

  18. Explicit presentations of nonspecial line bundles and secant spaces

    CERN Document Server

    Kim, Seonja

    2012-01-01

    A line bundle L on a smooth curve X is nonspecial if and only if L admits a presentation L=K_X -D +E for some effective divisors D and E>0 on X with gcd (D, E)=0 and h^0 (X, O_X (D))=1. In this work, we define a minimal presentation of L which is minimal with respect to the degree of E among the presentations. If L=K_X -D +E with degE>2 is a minimal, then L is very ample and any q-points of X with q bundle L=K_X -D +E on X with/without an n-secant (n-2)-plane of the embedded curve by taking divisors D and E on X. As its applications, we construct nonspecial line bundles which show the sharpness of Green and Lazarsfeld's Conjecture on property (N_p) for general n-gonal curves and simple multiple coverings of smooth plane curves.

  19. Real bundle gerbes, orientifolds and twisted KR-homology

    CERN Document Server

    Hekmati, Pedram; Szabo, Richard J; Vozzo, Raymond F

    2016-01-01

    We introduce a notion of Real bundle gerbes on manifolds equipped with an involution. We elucidate their relation to Jandl gerbes and prove that they are classified by their Real Dixmier-Douady class in Grothendieck's equivariant sheaf cohomology. We show that the Grothendieck group of Real bundle gerbe modules is isomorphic to twisted KR-theory for a torsion Real Dixmier-Douady class. Building on the Baum-Douglas model for K-homology and the orientifold construction in string theory, we introduce geometric cycles for twisted KR-homology groups using Real bundle gerbe modules. We prove that this defines a real-oriented generalised homology theory dual to twisted KR-theory for Real closed manifolds, and more generally for Real finite CW-complexes, for any Real Dixmier-Douady class. This is achieved by defining an explicit natural transformation to analytic twisted KR-homology and proving that it is an isomorphism. Our constructions give a new framework for the classification of orientifolds in string theory, p...

  20. An elastic model for bioinspired design of carbon nanotube bundles

    Science.gov (United States)

    Sun, Xiaoyu; Zhang, Zuoqi; Xu, Yuanjie; Zhang, Yongwei

    2015-04-01

    Collagen fibers provide a good example of making strong micro- or mesoscale fibers from nanoscale tropocollagen molecules through a staggered and cross-linked organization in a bottom-up manner. Mimicking the architectural features of collagen fibers has been shown to be a promising approach to develop carbon nanotube (CNT) fibers of high performance. In the present work, an elastic model is developed to describe the load transfer and failure propagation within the bioinspired CNT bundles, and to establish the relations of the mechanical properties of the bundles with a number of geometrical and physical parameters such as the CNT aspect ratio and longitudinal gap, interface cross-link density, and the functionalization-induced degradation in CNTs, etc. With the model, the stress distributions along the CNT-CNT interface as well as in every individual CNT are well captured, and the failure propagation along the interface and its effects on the mechanical properties of the CNT bundles are predicted. The work may provide useful guidelines for the design of novel CNT fibers in practice.