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Sample records for underwent reversible cyclization

  1. Study of cyclization of chelating compounds using electrospray ionization mass spectrometry

    International Nuclear Information System (INIS)

    Shi Ying; Campbell, J.A.

    2000-01-01

    Electrospray ionization mass spectrometry (ESI-MS) was used for the study of cyclization of organic chelating compounds (chelators). Four chelating compounds were studied: Symmetrical ethylenediaminediacetic acid (s-EDDA), Unsymmetrical ethylenediaminediacetic acid (u-EDDA), N-(2-hydroxyethyl) ethylenediaminetriacetic acid (HEDTA), and N-(2-hydroxyethyl)iminodiacetic acid (HEIDA). The chelators were cyclized with treatments of acids and heating. The open and cyclized form of the chelators were semi-quantified by both positive and negative ion modes ESI-MS. The kinetics of chelator cyclization was studied as a function of reaction temperature and the pH of the matrix. The cyclization of s-EDDA was found to be a pseudo-first order reaction in s-EDDA and overall second order. The cyclizations of HEIDA and HEDTA are reversible reactions. Higher temperature and lower pH favors cyclization. (author)

  2. ELECTROPHILIC CYCLIZATION OF DITERPENOIDS

    Directory of Open Access Journals (Sweden)

    Veaceslav Kulciţki

    2006-06-01

    Full Text Available A review of diterpenoid cyclization initiated by electrophilic reagents is provided. Conventional protonic and Lewis acids are examined along with superacids as initiators of cyclization cascade. An emphasis is placed on the use of cyclization reactions as a tool for the synthesis of compounds with potential practical utility. The review contains 74 references.

  3. The Cyclization of natural rubber

    International Nuclear Information System (INIS)

    Mirzataheri, M.

    2000-01-01

    The effect of solvent, temperature, time, weight percent of catalyst on the rate and mechanism of cyclization of natural rubber was studied in toluene and xylene solutions having tin tetra chloride catalyst (SnCl 4 ). Iodo metric titration show, with 8% SnCl 4 (based on polymer weight) cyclization occurs, leaving 27.4% of the total unsaturation. Infrared spectra of cyclized natural rubber show decreased absorption intensity at 840 and 780 cm -1 which are characteristic bands of the linear polymer and the appearance of absorption band at 890 cm -1 as cycles were formed. By using this chemical modification, natural rubber is transformed into a resinous thermoplastic, hard, non rubbery cyclized material with much less unsaturation than the original rubber, which could find commercial applications ad adhesives, printing inks, industrial and ship paints

  4. Engineering an Affinity-Enhanced Peptide through Optimization of Cyclization Chemistry.

    Science.gov (United States)

    Ngambenjawong, Chayanon; Pineda, Julio Marco B; Pun, Suzie H

    2016-12-21

    Peptide cyclization is a strategy used to improve stability and activity of peptides. The most commonly used cyclization method is disulfide bridge formation of cysteine-containing peptides, as is typically found in nature. Over the years, an increasing number of alternative chemistries for peptide cyclization with improved efficiency, kinetics, orthogonality, and stability have been reported. However, there has been less appreciation for the opportunity to fine-tune peptide activity via the diverse chemical entities introduced at the site of linkage by different cyclization strategies. Here, we demonstrate how cyclization optimization of an M2 "anti-inflammatory" macrophage-binding peptide (M2pep) resulted in a significant increase in binding affinity of the optimized analog to M2 macrophages while maintaining binding selectivity compared to M1 "pro-inflammatory" macrophages. In this study, we report synthesis and evaluation of four cyclic M2pep(RY) analogs with diverse cyclization strategies: (1) Asp-[amide]-Lys, (2) azido-Lys-[triazole(copper(I)-catalyzed alkyne-azide cycloaddition (CuAAC))]-propargyl-Gly, (3) Cys-[decafluorobiphenyl (DFBP)]-Cys, and (4) Cys-[decafluorobiphenyl sulfone (DFS)]-Cys, whereby the chemical entity or linker at the linkage site is shown in the square bracket and is between the residues involved in cyclization. These peptides are compared to a disulfide-cyclized M2pep(RY) that we previously reported as a serum-stable, affinity-enhanced analog to the original linear M2pep. DFBP-cyclized M2pep(RY) exhibits the highest binding activity to M2 macrophages with apparent dissociation constant (K D ) about 2.03 μM compared to 36.3 μM for the original disulfide-cyclized M2pep(RY) and 220 μM for the original linear peptide. DFS-cyclized M2pep(RY) also binds more strongly than the original cyclized analog, whereas amide- and triazole-cyclized M2pep(RY) analogs bind less strongly. We verified that DFBP alone has negligible binding to M2

  5. Enantioselective cyclizations and cyclization cascades of samarium ketyl radicals

    Science.gov (United States)

    Kern, Nicolas; Plesniak, Mateusz P.; McDouall, Joseph J. W.; Procter, David J.

    2017-12-01

    The rapid generation of molecular complexity from simple starting materials is a key challenge in synthesis. Enantioselective radical cyclization cascades have the potential to deliver complex, densely packed, polycyclic architectures, with control of three-dimensional shape, in one step. Unfortunately, carrying out reactions with radicals in an enantiocontrolled fashion remains challenging due to their high reactivity. This is particularly the case for reactions of radicals generated using the classical reagent, SmI2. Here, we demonstrate that enantioselective SmI2-mediated radical cyclizations and cascades that exploit a simple, recyclable chiral ligand can convert symmetrical ketoesters to complex carbocyclic products bearing multiple stereocentres with high enantio- and diastereocontrol. A computational study has been used to probe the origin of the enantioselectivity. Our studies suggest that many processes that rely on SmI2 can be rendered enantioselective by the design of suitable ligands.

  6. Iodine - catalyzed prins cyclization of aliphatic and aromatic ketones

    International Nuclear Information System (INIS)

    Kishore, K.R.; Reddy, K.; Silva Junior, Luiz F.

    2013-01-01

    Iodine-catalyzed Prins cyclization of homoallylic alcohols and ketones was investigated. Anhydrous conditions and inert atmosphere are not required in this metal-free protocol. The reaction of 2-(3,4-dihydronaphthalene-1-yl)propan-1-ol with six aliphatic symmetric ketones gave the desired products in 67-77% yield. Cyclization was performed with four aliphatic unsymmetric ketones, leading to corresponding pyrans in 66-76% yield. Prins cyclization was also accomplished with four aromatic ketones in 37-66% yield. Finally, Prins cyclization of the monoterpene isopulegol and acetone was successfully achieved. (author)

  7. Iodine - catalyzed prins cyclization of aliphatic and aromatic ketones

    Energy Technology Data Exchange (ETDEWEB)

    Kishore, K.R.; Reddy, K.; Silva Junior, Luiz F., E-mail: luizfsjr@iq.usp.br [Universidade de Sao Paulo (IQ/USP), SP (Brazil). Inst. de Quimica. Dept. de Quimica Fundamental

    2013-09-15

    Iodine-catalyzed Prins cyclization of homoallylic alcohols and ketones was investigated. Anhydrous conditions and inert atmosphere are not required in this metal-free protocol. The reaction of 2-(3,4-dihydronaphthalene-1-yl)propan-1-ol with six aliphatic symmetric ketones gave the desired products in 67-77% yield. Cyclization was performed with four aliphatic unsymmetric ketones, leading to corresponding pyrans in 66-76% yield. Prins cyclization was also accomplished with four aromatic ketones in 37-66% yield. Finally, Prins cyclization of the monoterpene isopulegol and acetone was successfully achieved. (author)

  8. Anodic Cyclization Reactions and the Mechanistic Strategies That Enable Optimization.

    Science.gov (United States)

    Feng, Ruozhu; Smith, Jake A; Moeller, Kevin D

    2017-09-19

    Oxidation reactions are powerful tools for synthesis because they allow us to reverse the polarity of electron-rich functional groups, generate highly reactive intermediates, and increase the functionality of molecules. For this reason, oxidation reactions have been and continue to be the subject of intense study. Central to these efforts is the development of mechanism-based strategies that allow us to think about the reactive intermediates that are frequently central to the success of the reactions and the mechanistic pathways that those intermediates trigger. For example, consider oxidative cyclization reactions that are triggered by the removal of an electron from an electron-rich olefin and lead to cyclic products that are functionalized for further elaboration. For these reactions to be successful, the radical cation intermediate must first be generated using conditions that limit its polymerization and then channeled down a productive desired pathway. Following the cyclization, a second oxidation step is necessary for product formation, after which the resulting cation must be quenched in a controlled fashion to avoid undesired elimination reactions. Problems can arise at any one or all of these steps, a fact that frequently complicates reaction optimization and can discourage the development of new transformations. Fortunately, anodic electrochemistry offers an outstanding opportunity to systematically probe the mechanism of oxidative cyclization reactions. The use of electrochemical methods allows for the generation of radical cations under neutral conditions in an environment that helps prevent polymerization of the intermediate. Once the intermediates have been generated, a series of "telltale indicators" can be used to diagnose which step in an oxidative cyclization is problematic for less successful transformation. A set of potential solutions to address each type of problem encountered has been developed. For example, problems with the initial

  9. In vitro structure-activity relationship of Re-cyclized octreotide analogues

    Energy Technology Data Exchange (ETDEWEB)

    Dannoon, Shorouk F. [Department of Chemistry, University of Missouri, Columbia, MO 65211 (United States); Bigott-Hennkens, Heather M. [Department of Veterinary Medicine and Surgery, University of Missouri, Columbia, MO 65211 (United States); Ma Lixin [Department of Radiology, University of Missouri, Columbia, MO 65211 (United States); International Institute of Nano and Molecular Medicine, University of Missouri, Columbia, MO 65211 (United States); Nuclear Science and Engineering Institute, University of Missouri, Columbia, MO 65211 (United States); Research Service, Harry S. Truman Memorial Veterans' Hospital, Columbia, MO 65201 (United States); Gallazzi, Fabio [Structural Biology Core, University of Missouri, Columbia, MO 65211 (United States); Lewis, Michael R., E-mail: lewismic@missouri.ed [Department of Veterinary Medicine and Surgery, University of Missouri, Columbia, MO 65211 (United States); Department of Radiology, University of Missouri, Columbia, MO 65211 (United States); Nuclear Science and Engineering Institute, University of Missouri, Columbia, MO 65211 (United States); Research Service, Harry S. Truman Memorial Veterans' Hospital, Columbia, MO 65201 (United States); Jurisson, Silvia S., E-mail: jurissons@missouri.ed [Department of Chemistry, University of Missouri, Columbia, MO 65211 (United States); Department of Radiology, University of Missouri, Columbia, MO 65211 (United States); Nuclear Science and Engineering Institute, University of Missouri, Columbia, MO 65211 (United States)

    2010-07-15

    Introduction: Development of radiolabeled octreotide analogues is of interest for targeting somatostatin receptor (SSTR)-positive tumors for diagnostic and therapeutic purposes. We are investigating a direct labeling approach for incorporation of a Re ion into octreotide analogues, where the peptide sequences are cyclized via coordination to Re rather than through a disulfide bridge. Methods: Various octreotide analogue sequences and coordination systems (e.g., S{sub 2}N{sub 2} and S{sub 3}N) were synthesized and cyclized with nonradioactive Re. In vitro competitive binding assays with {sup 111}In-DOTA-Tyr{sup 3}-octreotide in AR42J rat pancreatic tumor cells yielded IC{sub 50} values as a measure of SSTR affinity of the Re-cyclized analogues. Three-dimensional structures of Re-cyclized Tyr{sup 3}-octreotate and its disulfide-bridged analogue were calculated from two-dimensional NMR experiments to visualize the effect of metal cyclization on the analogue's pharmacophore. Results: Only two of the 11 Re-cyclized analogues investigated showed moderate in vitro binding affinity toward somatostatin subtype 2 receptors. Three-dimensional molecular structures of Re- and disulfide-cyclized Tyr{sup 3}-octreotate were calculated, and both of their pharmacophore turns appear to be very similar with minor differences due to metal coordination to the amide nitrogen of one of the pharmacophore amino acids. Conclusions: Various Re-cyclized analogues were developed and analogue 4 had moderate affinity toward somatostatin subtype 2 receptors. In vitro stable studies that are in progress showed stable radiometal cyclization of octreotide analogues via NS{sub 3} and N{sub 2}S{sub 2} coordination forming five- and six-membered chelate rings. In vivo biodistribution studies are underway of {sup 99m}Tc-cyclized analogue 4.

  10. Cyclization of arylacetoacetates to indene and dihydronaphthalene derivatives in strong acids. Evidence for involvement of further protonation of O,O-diprotonated beta-ketoester, leading to enhancement of cyclization.

    Science.gov (United States)

    Kurouchi, Hiroaki; Sugimoto, Hiromichi; Otani, Yuko; Ohwada, Tomohiko

    2010-01-20

    The chemical features, such as substrate stability, product distribution, and substrate generality, and the reaction mechanism of Brønsted superacid-catalyzed cyclization reactions of aromatic ring-containing acetoacetates (beta-ketoesters) were examined in detail. While two types of carbonyl cyclization are possible, i.e., keto cyclization and ester cyclization, the former was found to take place exclusively. The reaction constitutes an efficient method to synthesize indene and 3,4-dihydronapthalene derivatives. Acid-base titration monitored with (13)C NMR spectroscopy showed that the acetoacetates are fully O(1),O(3)-diprotonated at H(0) = -11. While the five-membered ring cyclization of the arylacetoacetates proceeded slowly at H(0) = -11, a linear increase in the rate of the cyclization was found with increasing acidity in the high acidity region of H(0) = -11.8 to -13.3. Therefore, the O(1),O(3)-diprotonated acetoacetates exhibited some cyclizing reactivity, but they are not the reactive intermediates responsible for the acceleration of the cyclization in the high acidity region. The reactive cationic species might be formed by further protonation (or protosolvation) of the O(1),O(3)-diprotonated acetoacetates; i.e., they may be tricationic species. Thermochemical data on the acid-catalyzed cyclization of the arylacetoacetates showed that the activation energy is decreased significantly as compared with that of the related acid-catalyzed cyclization reaction of a compound bearing a single functional group, such as a ketone. These findings indicate that intervention of the trication contributes to the activation of the cyclization of arylacetoacetates in strong acid, and the electron-withdrawing nature of the O-protonated ester functionality significantly increases the electrophilicity of the ketone moiety.

  11. Reverse cope elimination of hydroxylamines and alkenes or alkynes: theoretical investigation of tether length and substituent effects.

    Science.gov (United States)

    Krenske, Elizabeth H; Davison, Edwin C; Forbes, Ian T; Warner, Jacqueline A; Smith, Adrian L; Holmes, Andrew B; Houk, K N

    2012-02-01

    Quantum mechanical calculations have been used to study the intramolecular additions of hydroxylamines to alkenes and alkynes ("reverse Cope eliminations"). In intermolecular reverse Cope eliminations, alkynes are more reactive than alkenes. However, competition experiments have shown that tethering the hydroxylamine to the alkene or alkyne can reverse the reactivity order from that normally observed. The exact outcome depends on the length of the tether. In agreement with experiment, a range of density functional theory methods and CBS-QB3 calculations predict that the activation energies for intramolecular reverse Cope eliminations follow the order 6-exo-dig hydroxylamine and alkyne. Cyclization onto an alkene in the 5-exo-trig fashion incurs slightly less tether strain than a 6-exo-dig alkyne cyclization, but its activation energy is higher because the hydroxylamine fragment must distort more before the TS is reached. If the alkene terminus is substituted with two methyl groups, the barrier becomes so much higher that it is also disfavored compared to the 5- and 7-exo-dig cyclizations. © 2012 American Chemical Society

  12. In situ cyclization modification in polymerization of butadiene by rare earth coordination catalyst

    International Nuclear Information System (INIS)

    Wang Chaoyang

    2005-01-01

    Butadiene was polymerized to a certain extent in the presence of a rare earth coordination catalyst, neodymium compound of neodymium chloride and i-propyl alcohol and triethyl aluminum (NdCl 3 ·3i-PrOH-AlEt 3 ) in toluene and the allyl chloride was then added to the reactive solution in order to in situ cyclize the formed polybutadiene and cyclopolymerize the unreacted butadiene monomers. Effects of molar ratio of allylchloride to AlEt 3 (Cl/Al), cyclization reaction time and temperature, butadiene and NdCl 3 ·3i-PrOH concentrations on the cyclization reaction have been investigated. The cyclization reaction is very quick, only several minutes. The cyclization reaction temperature has few effects on the properties of the cyclized product. Cl/Al is a very important condition for this reaction system. Cyclized polybutadiene has a low value of intrinsic viscosity, free gelling and high yield at high Cl/Al. The microstructures and properties of the cyclized products have been characterized by Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy and gel permeation chromatography. The cyclization mechanism is put forward

  13. Structural determinants of reductive terpene cyclization in iridoid biosynthesis

    DEFF Research Database (Denmark)

    Kries, Hajo; Caputi, Lorenzo; Stevenson, Clare E M

    2016-01-01

    The carbon skeleton of ecologically and pharmacologically important iridoid monoterpenes is formed in a reductive cyclization reaction unrelated to canonical terpene cyclization. Here we report the crystal structure of the recently discovered iridoid cyclase (from Catharanthus roseus) bound...

  14. The Reverse Cope Elimination of Hydroxylamines and Alkenes or Alkynes: Theoretical Investigation of Tether Length and Substituent Effects

    Science.gov (United States)

    Krenske, Elizabeth H.; Davison, Edwin C.; Forbes, Ian T.; Warner, Jacqueline A.; Smith, Adrian L.; Holmes, Andrew B.; Houk, K. N.

    2012-01-01

    Quantum mechanical calculations have been used to study the intramolecular additions of hydroxylamines to alkenes and alkynes (“reverse Cope eliminations”). In intermolecular reverse Cope eliminations, alkynes are more reactive than alkenes. However, competition experiments have shown that tethering the hydroxylamine to the alkene or alkyne can reverse the reactivity order from that normally observed. The exact outcome depends on the length of the tether. In agreement with experiment, a range of density functional theory methods and CBS-QB3 calculations predict that the activation energies for intramolecular reverse Cope eliminations follow the order 6-exo-dig hydroxylamine and alkyne. Cyclization onto an alkene in the 5-exo-trig fashion incurs slightly less tether strain than a 6-exo-dig alkyne cyclization, but its activation energy is higher because the hydroxylamine fragment must distort more before the TS is reached. If the alkene terminus is substituted with two methyl groups, the barrier becomes so much higher that it is also disfavored compared to the 5- and 7-exo-dig cyclizations. PMID:22280245

  15. Knottin cyclization: impact on structure and dynamics

    Directory of Open Access Journals (Sweden)

    Gracy Jérôme

    2008-12-01

    Full Text Available Abstract Background Present in various species, the knottins (also referred to as inhibitor cystine knots constitute a group of extremely stable miniproteins with a plethora of biological activities. Owing to their small size and their high stability, knottins are considered as excellent leads or scaffolds in drug design. Two knottin families contain macrocyclic compounds, namely the cyclotides and the squash inhibitors. The cyclotide family nearly exclusively contains head-to-tail cyclized members. On the other hand, the squash family predominantly contains linear members. Head-to-tail cyclization is intuitively expected to improve bioactivities by increasing stability and lowering flexibility as well as sensitivity to proteolytic attack. Results In this paper, we report data on solution structure, thermal stability, and flexibility as inferred from NMR experiments and molecular dynamics simulations of a linear squash inhibitor EETI-II, a circular squash inhibitor MCoTI-II, and a linear analog lin-MCoTI. Strikingly, the head-to-tail linker in cyclic MCoTI-II is by far the most flexible region of all three compounds. Moreover, we show that cyclic and linear squash inhibitors do not display large differences in structure or flexibility in standard conditions, raising the question as to why few squash inhibitors have evolved into cyclic compounds. The simulations revealed however that the cyclization increases resistance to high temperatures by limiting structure unfolding. Conclusion In this work, we show that, in contrast to what could have been intuitively expected, cyclization of squash inhibitors does not provide clear stability or flexibility modification. Overall, our results suggest that, for squash inhibitors in standard conditions, the circularization impact might come from incorporation of an additional loop sequence, that can contribute to the miniprotein specificity and affinity, rather than from an increase in conformational rigidity

  16. Synthesis of anatoxin a via intramolecular cyclization of iminium salts

    International Nuclear Information System (INIS)

    Bates, H.A.; Rapoport, H.

    1979-01-01

    Anatoxin a (1) has been synthesized by exploiting intramolecular cyclization between an iminium salt and a nucleophilic carbon to construct the 9-azabicyclo[4.2.1]nonane ring system. Cyclization of malonate iminiumsalt 16 at alkaline pH afforded a low yield of bicyclic malonate 18 owing to an unfavorable equilibrium constant and lability of the iminium salt in base. In contrast, cyclization of ketoiminium salt 31 afforded a good yield of bicyclic ketone 34 in acidic methanol. Dihydropyrrolium salts 16 and 31 were generated quantitatively by decarbonylation of substituted N-methylprolines 15 and 30b, obtained by reduction of the corresponding pyrroles

  17. Self-Terminating, Oxidative Radical Cyclizations

    Directory of Open Access Journals (Sweden)

    Uta Wille

    2004-05-01

    Full Text Available The recently discovered novel concept of self-terminating, oxidative radical cyclizations, through which alkynes can be converted into carbonyl compounds under very mild reaction conditions using O-centered inorganic and organic radicals as oxidants, is described

  18. Energy profiles for ketene cyclizations. Interconversion of 1,3-oxazin-6-ones, mesoionic 1,3-oxazinium olates and acylketenes, imidoylketenes, oxoketenimines, and cyclization products.

    Science.gov (United States)

    Bornemann, Holger; Wentrup, Curt

    2005-07-22

    The energy surface connecting oxazinium olates 9, several possible conformers of ketenes 10 and 11, and the final cyclization products 12, 13 and 14, as well as the isomeric 1,3-oxazine-6-ones 15, ring opening of the latter to N-acylimidoylketenes 16, and subsequent rearrangement of 16 to oxoketenimines 17, azetinones 18, and the cyclization products 19 and 20 are evaluated computationally at the B3LYP/6-31G and B3LYP/6-311+G//B3LYP/6-31G levels. The cyclizations of ketenes to oxazinium olates 9 and oxazines 15 have the characteristics of pseudopericyclic reactions. Plots of the energy vs internal reaction coordinate for the cyclization of transoid acylketenes such as 10 to 9 (via TS1) and 16 to 15 (via TS7) feature two inflection points and indicate that the part of the energy surface above the lower inflection points describe internal rotation of the acyl function in the ketene moiety, and the part below this point describes the cyclization of the cisoid ketene to the planar mesoionic oxazinium olate 9 or oxazinone 15. The 1,3-shifts of the OR group that interconvert ketenes 16 and ketenimines 17 via four-membered cyclic transition states TS8 behave similarly, the first portion (from the ketenimine side) of the activation barrier being due largely to internal rotation of substituents, and the top part being due to the 1,3-shift proper.

  19. Cyclization of the N-Terminal X-Asn-Gly Motif during Sample Preparation for Bottom-Up Proteomics

    DEFF Research Database (Denmark)

    Zhang, Xumin; Højrup, Peter

    2010-01-01

    We, herein, report a novel -17 Da peptide modification corresponding to an N-terminal cyclization of peptides possessing the N-terminal motif of X-Asn-Gly. The cyclization occurs spontaneously during sample preparation for bottom-up proteomics studies. Distinct from the two well-known N-terminal ......We, herein, report a novel -17 Da peptide modification corresponding to an N-terminal cyclization of peptides possessing the N-terminal motif of X-Asn-Gly. The cyclization occurs spontaneously during sample preparation for bottom-up proteomics studies. Distinct from the two well-known N......-terminal cyclizations, cyclization of N-terminal glutamine and S-carbamoylmethylcysteine, it is dependent on pH instead of [NH(4)(+)]. The data set from our recent study on large-scale N(α)-modified peptides revealed a sequence requirement for the cyclization event similar to the well-known deamidation of Asn to iso...

  20. SpyRing interrogation: analyzing how enzyme resilience can be achieved with phytase and distinct cyclization chemistries

    Science.gov (United States)

    Schoene, Christopher; Bennett, S. Paul; Howarth, Mark

    2016-01-01

    Enzymes catalyze reactions with exceptional selectivity and rate acceleration but are often limited by instability. Towards a generic route to thermo-resilience, we established the SpyRing approach, cyclizing enzymes by sandwiching between SpyTag and SpyCatcher (peptide and protein partners which lock together via a spontaneous isopeptide bond). Here we first investigated the basis for this resilience, comparing alternative reactive peptide/protein pairs we engineered from Gram-positive bacteria. Both SnoopRing and PilinRing cyclization gave dramatic enzyme resilience, but SpyRing cyclization was the best. Differential scanning calorimetry for each ring showed that cyclization did not inhibit unfolding of the inserted β-lactamase. Cyclization conferred resilience even at 100 °C, where the cyclizing domains themselves were unfolded. Phytases hydrolyze phytic acid and improve dietary absorption of phosphate and essential metal ions, important for agriculture and with potential against human malnutrition. SpyRing phytase (PhyC) resisted aggregation and retained catalytic activity even following heating at 100 °C. In addition, SpyRing cyclization made it possible to purify phytase simply by heating the cell lysate, to drive aggregation of non-cyclized proteins. Cyclization via domains forming spontaneous isopeptide bonds is a general strategy to generate resilient enzymes and may extend the range of conditions for isolation and application of enzymes. PMID:26861173

  1. Cyclization strategies of meditopes: affinity and diffraction studies of meditope–Fab complexes

    International Nuclear Information System (INIS)

    Bzymek, Krzysztof P.; Ma, Yuelong; Avery, Kendra A.; Horne, David A.; Williams, John C.

    2016-01-01

    An overview of cyclization strategies of a Fab-binding peptide to maximize affinity. Recently, a unique binding site for a cyclic 12-residue peptide was discovered within a cavity formed by the light and heavy chains of the cetuximab Fab domain. In order to better understand the interactions that drive this unique complex, a number of variants including the residues within the meditope peptide and the antibody, as well as the cyclization region of the meditope peptide, were created. Here, multiple crystal structures of meditope peptides incorporating different cyclization strategies bound to the central cavity of the cetuximab Fab domain are presented. The affinity of each cyclic derivative for the Fab was determined by surface plasmon resonance and correlated to structural differences. Overall, it was observed that the disulfide bond used to cyclize the peptide favorably packs against a hydrophobic ‘pocket’ and that amidation and acetylation of the original disulfide meditope increased the overall affinity ∼2.3-fold. Conversely, replacing the terminal cysteines with serines and thus creating a linear peptide reduced the affinity over 50-fold, with much of this difference being reflected in a decrease in the on-rate. Other cyclization methods, including the formation of a lactam, reduced the affinity but not to the extent of the linear peptide. Collectively, the structural and kinetic data presented here indicate that small perturbations introduced by different cyclization strategies can significantly affect the affinity of the meditope–Fab complex

  2. Cyclization strategies of meditopes: affinity and diffraction studies of meditope–Fab complexes

    Energy Technology Data Exchange (ETDEWEB)

    Bzymek, Krzysztof P.; Ma, Yuelong; Avery, Kendra A.; Horne, David A.; Williams, John C., E-mail: jcwilliams@coh.org [Beckman Research Institute of City of Hope, 1710 Flower Street, Duarte, CA 91010 (United States)

    2016-05-23

    An overview of cyclization strategies of a Fab-binding peptide to maximize affinity. Recently, a unique binding site for a cyclic 12-residue peptide was discovered within a cavity formed by the light and heavy chains of the cetuximab Fab domain. In order to better understand the interactions that drive this unique complex, a number of variants including the residues within the meditope peptide and the antibody, as well as the cyclization region of the meditope peptide, were created. Here, multiple crystal structures of meditope peptides incorporating different cyclization strategies bound to the central cavity of the cetuximab Fab domain are presented. The affinity of each cyclic derivative for the Fab was determined by surface plasmon resonance and correlated to structural differences. Overall, it was observed that the disulfide bond used to cyclize the peptide favorably packs against a hydrophobic ‘pocket’ and that amidation and acetylation of the original disulfide meditope increased the overall affinity ∼2.3-fold. Conversely, replacing the terminal cysteines with serines and thus creating a linear peptide reduced the affinity over 50-fold, with much of this difference being reflected in a decrease in the on-rate. Other cyclization methods, including the formation of a lactam, reduced the affinity but not to the extent of the linear peptide. Collectively, the structural and kinetic data presented here indicate that small perturbations introduced by different cyclization strategies can significantly affect the affinity of the meditope–Fab complex.

  3. Asymmetric, Stereodivergent Synthesis of (−)-Clusianone Utilizing a Biomimetic Cationic Cyclization **

    Science.gov (United States)

    Boyce, Jonathan H.

    2014-01-01

    We report a stereodivergent, asymmetric total synthesis of (−)-clusianone in six steps from commercial materials. We implement a challenging cationic cyclization forging a bond between two sterically encumbered quaternary carbons. Mechanistic studies point to the unique ability of formic acid to bring about successful cyclization to the clusianone framework. PMID:24916169

  4. Nazarov cyclization initiated by peracid oxidation: the total synthesis of (+/-)-rocaglamide.

    Science.gov (United States)

    Malona, John A; Cariou, Kevin; Frontier, Alison J

    2009-06-10

    The total syntheses of aglafolin, rocagloic acid, and rocaglamide using Nazarov cyclization are described. Generation of the necessary oxyallyl cation intermediate was accomplished via peracid oxidation of an allenol ether to generate an unusual oxycarbenium ion species that undergoes cyclization. The synthesis is efficient, highly diastereoselective, and strategically distinct from previous syntheses of rocaglamide.

  5. Oxidative cyclization of prodigiosin by an alkylglycerol monooxygenase-like enzyme

    DEFF Research Database (Denmark)

    de Rond, Tristan; Stow, Parker; Eigl, Ian

    2017-01-01

    Prodiginines, which are tripyrrole alkaloids displaying a wide array of bioactivities, occur as linear and cyclic congeners. Identification of an unclustered biosynthetic gene led to the discovery of the enzyme responsible for catalyzing the regiospecific C–H activation and cyclization of prodigi...... of prodigiosin to cycloprodigiosin in Pseudoalteromonas rubra. This enzyme is related to alkylglycerol monooxygenase and unrelated to RedG, the Rieske oxygenase that produces cyclized prodiginines in Streptomyces, implying convergent evolution....

  6. SpyRings Declassified: A Blueprint for Using Isopeptide-Mediated Cyclization to Enhance Enzyme Thermal Resilience.

    Science.gov (United States)

    Schoene, C; Bennett, S P; Howarth, M

    2016-01-01

    Enzymes often have marginal stability, with unfolding typically leading to irreversible denaturation. This sensitivity is a major barrier, both for de novo enzyme development and for expanding enzyme impact beyond the laboratory. Seeking an approach to enhance resilience to denaturation that could be applied to a range of different enzymes, we developed SpyRing cyclization. SpyRings contain genetically encoded SpyTag (13 amino acids) on the N-terminus and SpyCatcher (12kDa) on the C-terminus of the enzyme, so that the Spy partners spontaneously react together through an irreversible isopeptide bond. SpyRing cyclization gave major increases in thermal resilience, including on a model for enzyme evolution, β-lactamase, and an industrially important enzyme in agriculture and nutrition, phytase. We outline the SpyRing rationale, including comparison of SpyRing cyclization to other cyclization strategies. The cloning strategy is presented for the simple insertion of enzyme genes for recombinant expression. We discuss structure-based approaches to select suitable enzyme cyclization targets. Approaches to evaluate the cyclization reaction and its effect on enzyme resilience are described. We also highlight the use of differential scanning calorimetry to understand how SpyRing cyclization promotes enzyme refolding. Efficiently searching sequence space will continue to be important for enzyme improvement, but the SpyRing platform may be a valuable rational adjunct for conferring resilience. © 2016 Elsevier Inc. All rights reserved.

  7. Diversity-Oriented Synthesis of Coumarin-Linked Benzimidazoles via a One-Pot, Three-Step, Intramolecular Knoevenagel Cyclization.

    Science.gov (United States)

    Yao, Po-Hsin Eric; Kumar, Sunil; Liu, Yu-Li; Fang, Chiu-Ping; Liu, Chia-Chen; Sun, Chung-Ming

    2017-04-10

    Diversity-oriented synthesis of coumarin-linked benzimidazoles from N-(2-aminophenyl)-2-cyanoacetamide was achieved via a one-pot, three-step sequential reaction in excellent yields. In situ intramolecular cyclization of the cyanoacetamide afforded benzimidazoles which subsequently underwent a Knoevenagel condensation of the 2-cyanomethylbenzimidazoles with salicylaldehydes promoted by triethylamine to reach the target compounds. An important intermediate, 2-(2-imino-2H-chromen-3-yl)-1H-benzimidazole was characterized by X-ray analysis and further hydrolyzed to 2-(coumarin-3-yl)benzimidazole in acidic condition. Among the synthesized compounds, some were found to be promising inhibitors of porcine kidney d-amino acid oxidase (pkDAO).

  8. Azirinium ylides from α-diazoketones and 2H-azirines on the route to 2H-1,4-oxazines: three-membered ring opening vs 1,5-cyclization

    Directory of Open Access Journals (Sweden)

    Nikolai V. Rostovskii

    2015-03-01

    Full Text Available Strained azirinium ylides derived from 2H-azirines and α-diazoketones under Rh(II-catalysis can undergo either irreversible ring opening across the N–C2 bond to 2-azabuta-1,3-dienes that further cyclize to 2H-1,4-oxazines or reversibly undergo a 1,5-cyclization to dihydroazireno[2,1-b]oxazoles. Dihydroazireno[2,1-b]oxazoles derived from 3-aryl-2H-azirines and 3-diazoacetylacetone or ethyl diazoacetoacetate are able to cycloadd to acetyl(methylketene generated from 3-diazoacetylacetone under Rh(II catalysis to give 4,6-dioxa-1-azabicyclo[3.2.1]oct-2-ene and/or 5,7-dioxa-1-azabicyclo[4.3.1]deca-3,8-diene-2-one derivatives. According to DFT calculations (B3LYP/6-31+G(d,p, the cycloaddition can involve two modes of nucleophilic attack of the dihydroazireno[2,1-b]oxazole intermediate on acetyl(methylketene followed by aziridine ring opening into atropoisomeric oxazolium betaines and cyclization. Azirinium ylides generated from 2,3-di- and 2,2,3-triaryl-substituted azirines give rise to only 2-azabuta-1,3-dienes and/or 2H-1,4-oxazines.

  9. Ruthenium-catalyzed cyclization of N-carbamoyl indolines with alkynes: an efficient route to pyrroloquinolinones.

    Science.gov (United States)

    Manoharan, Ramasamy; Jeganmohan, Masilamani

    2015-09-21

    A regioselective synthesis of substituted pyrroloquinolinones via a ruthenium-catalyzed oxidative cyclization of substituted N-carbamoyl indolines with alkynes is described. The cyclization reaction was compatible with various symmetrical and unsymmetrical alkynes including substituted propiolates. Later, we performed the aromatization of pyrroloquinolinones into indole derivatives in the presence of 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ).

  10. Tandem dinucleophilic cyclization of cyclohexane-1,3-diones with pyridinium salts

    Directory of Open Access Journals (Sweden)

    Mostafa Kiamehr

    2013-06-01

    Full Text Available The cyclization of cyclohexane-1,3-diones with various substituted pyridinium salts afforded functionalized 8-oxa-10-aza-tricyclo[7.3.1.02,7]trideca-2(7,11-dienes. The reaction proceeds by regioselective attack of the central carbon atom of the 1,3-dicarbonyl unit to 4-position of the pyridinium salt and subsequent cyclization by base-assisted proton migration and nucleophilic addition of the oxygen atom to the 2-position, as was elucidated by DFT computations. Fairly extensive screening of bases and additives revealed that the presence of potassium cations is essential for formation of the product.

  11. Proline-catalysed asymmetric ketol cyclizations: The template ...

    Indian Academy of Sciences (India)

    Unknown

    Abstract. A modified template mechanism based on modelling studies of energy minimised complexes is presented for the asymmetric proline-catalysed cyclization of triketones 1, 2 and 3 to the 2S,3S-ketols. 1a, 2a and 3a respectively. The template model involves a three-point contact as favoured in enzyme– substrate ...

  12. Chain elongation and cyclization in type III PKS DpgA.

    Science.gov (United States)

    Wu, Hai-Chen; Li, Yi-San; Liu, Yu-Chen; Lyu, Syue-Yi; Wu, Chang-Jer; Li, Tsung-Lin

    2012-04-16

    Chain elongation and cyclization of precursors of dihydroxyphenylacetyl-CoA (DPA-CoA) catalyzed by the bacterial type III polyketide synthase DpgA were studied. Two labile intermediates, di- and tri-ketidyl-CoA (DK- and TK-CoA), were proposed and chemically synthesized. In the presence of DpgABD, each of these with [(13)C(3)]malonyl-CoA (MA-CoA) was able to form partially (13)C-enriched DPA-CoA. By NMR and MS analysis, the distribution of (13)C atoms in the partially (13)C-enriched DPA-CoA shed light on how the polyketide chain elongates and cyclizes in the DpgA-catalyzed reaction. Polyketone intermediates elongate in a manner different from that which had been believed: two molecules of DK-CoA, or one DK-CoA plus one acetoacetyl-CoA (AA-CoA), but not two molecules of AA-CoA can form one molecule of DPA-CoA. As a result, polyketidyl-CoA serves as both the starter and extender, whereas polyketone-CoA without the terminal carboxyl group can only act as an extender. The terminal carboxyl group is crucial for the cyclization that likely takes place on CoA. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Bergman cyclization in polymer chemistry and material science.

    Science.gov (United States)

    Xiao, Yuli; Hu, Aiguo

    2011-11-01

    Bergman cyclization of enediynes, regarded as a promising strategy for anticancer drugs, now finds its own niche in the area of polymer chemistry and material science. The highly reactive aromatic diradicals generated from Bergman cyclization can undergo polymerization acting as either monomers or initiators of other vinyl monomers. The former, namely homopolymerization, leads to polyphenylenes and polynaphthalenes with excellent thermal stability, good solubility, and processability. The many remarkable properties of these aromatic polymers have further endowed them to be manufactured into carbon-rich materials, e.g., glassy carbons and carbon nanotubes. Whereas used as initiators, enediynes provide a novel resource for high molecular weight polymers with narrow polydispersities. The aromatic diradicals are also useful for introducing oligomers or polymers onto pristine carbonous nanomaterials, such as carbon nano-onions and carbon nanotubes, to improve their dispersibility in organic solvents and polymer solutions. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Posterior Reversible Encephalopathy Syndrome in Patients who Underwent Cardiovascular Surgery

    International Nuclear Information System (INIS)

    Granados, Ana Maria; Bueno Melo, Juliana; Acosta Puentes, Diana

    2012-01-01

    The etiology of posterior reversible encephalopathy syndrome (pres) is not well understood. This entity has been reported in relation to multiple clinical conditions. It has been proposed that the vertebrobasilar circulation is more sensitive to injuries sustained by the central nervous system. Consequently, the main radiologic manifestations of this condition occur in the pareto-occipital regions. As its name implies, pres has a reversible nature. Once the noxious factors are withdrawn, both the vasogenic edema in affected areas, as well as neurological symptoms tends to resolve, whereas if the situation persists the lesions may progress to parenchymal ischemia. Cerebral computed tomography (CT) in pres may show hypodense areas in the affected white matter. Magnetic resonance (MR) imaging is used to better characterize the abnormal regions. This modality is capable of displaying an increased signal intensity in these areas on T2-weighted FLAIR sequences that is less apparent on diffusion-weighted images. In order to confirm this diagnosis, a follow up imaging study either with CT or MR can be performed approximately four weeks after the onset of symptoms. Nevertheless, an exact consensus with respect to the follow-up period has not been reached. The supporting findings for this diagnosis include resolution of the affected white matter and clinical remission without neurological sequelae. We hereby report three proven cases of pres in patients of different age groups that had undergone major cardiovascular surgery with extracorporeal circulation, a common factor that was thought to have been the precursor to this condition in these individuals.

  15. Epimerization-free C-terminal peptide activation, elongation and cyclization

    NARCIS (Netherlands)

    Popović, S.

    2015-01-01

    C-terminal peptide activation and cyclization reactions are generally accompanied with epimerization (partial loss of C‐terminal stereointegrity). Therefore, the focus of this thesis was to develop epimerization-free methods for C-terminal peptide activation to enable C-terminal peptide elongation

  16. Photochemical Aryl Radical Cyclizations to Give (E-3-Ylideneoxindoles

    Directory of Open Access Journals (Sweden)

    Michael Gurry

    2014-09-01

    Full Text Available (E-3-Ylideneoxindoles are prepared in methanol in reasonable to good yields, as adducts of photochemical 5-exo-trig of aryl radicals, in contrast to previously reported analogous radical cyclizations initiated by tris(trimethylsilylsilane and azo-initiators that gave reduced oxindole adducts.

  17. Microwave-assisted reductive cyclization: An easy entry to the indoloquinolines and spiro[2H-indole-2,30-oxindole].

    Digital Repository Service at National Institute of Oceanography (India)

    Parvatkar, P.T.; Majik, M.S.

    and 15 can be synthesized from a common intermediate 16 via reductive cyclization reaction. The key intermediate 16 in turn can be obtained by Wittig reaction of (2-nitrobenzyl)triphenylphosphonium bromide with isatin. Hence compound 16 could... be considered as an advance intermediate for preparation of alkaloids in present work. N N 1 N H N 11 N H N 15NH O O2NN H O O + PPh3 NO2 + Br- 16 17 18 N N13 Wittig reaction reductive cyclization N-Methylation N-Methylation reductive cyclization Scheme 1...

  18. Double reductive cyclization: A facile synthesis of the indoloquinoline alkaloid cryptotackieine

    Digital Repository Service at National Institute of Oceanography (India)

    Parvatkar, P.T.; Parameswaran, P.S.; Tilve, S.G.

    A new synthesis of the indoloquinoline alkaloid cryptotackieine, isolated from Cryptolepis sanguinolenta, is described which involves a Perkin reaction, a tandem double reduction-double cyclization reaction followed by regioselective methylation...

  19. Synthesis and mechanism of formation of oxadeazaflavines by microwave thermal cyclization of ortho-halobenzylidene barbiturates

    Energy Technology Data Exchange (ETDEWEB)

    Figueroa-Villar, J. Daniel; Oliveira, Sandra C.G. de, E-mail: figueroa@ime.eb.br [Grupo de Quimica Medicinal, Departamento de Quimica, Instituto Militar de Engenharia, Rio de Janeiro, RJ (Brazil)

    2011-09-15

    The thermal cyclization reaction of o-halobenzylidene barbiturates was developed as an efficient and simple method for the preparation of oxadeazaflavines. The use of solid state reaction conditions with microwave irradiation afforded the products in 5 min with 47 to 98% yield. Experimental synthetic results and thermogravimetric reaction analyses agree with the molecular modeling mechanism simulation, indicating that this reaction occurs through an intramolecular hetero-Diels-Alder cyclization followed by fast re-aromatization. (author)

  20. Labeling, stability and biodistribution studies of {sup 99m}Tc-cyclized Tyr{sup 3}-octreotate derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Bigott-Hennkens, Heather M. [Department of Veterinary Medicine and Surgery, University of Missouri, Columbia, MO 65211 (United States); Dannoon, Shorouk F.; Noll, Samantha M. [Department of Chemistry, University of Missouri, Columbia, MO 65211 (United States); Ruthengael, Varyanna C. [Research Service, Harry S Truman Memorial Veterans' Hospital, Columbia, MO 65201 (United States); Jurisson, Silvia S., E-mail: JurissonS@missouri.ed [Department of Chemistry, University of Missouri, Columbia, MO 65211 (United States); Lewis, Michael R., E-mail: LewisMic@missouri.ed [Department of Veterinary Medicine and Surgery, University of Missouri, Columbia, MO 65211 (United States); Research Service, Harry S Truman Memorial Veterans' Hospital, Columbia, MO 65201 (United States)

    2011-05-15

    Introduction: To probe the interplay between radiotracer stability and somatostatin receptor affinity, Tyr{sup 3}-octreotate and six variations of its peptide sequence, for which the Re-cyclized products were previously reported, were radiolabeled with {sup 99m}Tc and investigated for their in vitro stability. Methods: Radiolabeling of the peptides was effected by ligand exchange from {sup 99m}Tc-glucoheptonate, and the desired products were purified by radio-RP-HPLC. The in vitro stability in phosphate buffered saline, mouse serum and cysteine solutions at physiological temperature and pH for all seven {sup 99m}Tc-cyclized peptides was determined by radio-RP-HPLC and radio-TLC. Normal CF-1 mouse biodistribution studies were performed for three of the {sup 99m}Tc-cyclized peptides. Results: Based on the fully characterized Re-cyclized peptide analogues, four {sup 99m}Tc-coordination motifs were proposed for the {sup 99m}Tc-cyclized peptides. Technetium-99m-cyclized Tyr{sup 3}-octreotate derivatives with N{sub 2}S{sub 2} metal coordination modes and large metal ring sizes were susceptible to oxidation and loss of {sup 99m}Tc in the form of {sup 99m}TcO{sub 4}{sup -}, as evidenced by their instability in the various solutions under physiological conditions (15-58% intact at 24 h). As anticipated, the addition of a third cysteine to the sequence stabilized the {sup 99m}Tc metal coordination, and peptides with NS{sub 3} coordination modes remained >85% intact out to 24 h. No significant differences were observed in the biodistribution studies performed with three peptides of varying stabilities. Conclusions: Improvements in stability were not sufficient to outweigh the low somatostatin receptor affinity for the peptides in this study. Further improvements in the peptide sequence and/or metal coordination are needed to result in a radiodiagnostic/radiotherapeutic pair for targeting the somatostatin receptor.

  1. Photodecarboxylative Cyclizations of ω-Phthalimido-para-phenoxy Carboxylates

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ae Rhan; Lee, Younsik; Yoo, Dong Jin [Chonbuk National Univ., Jeonju (Korea, Republic of); Cho, Hyunseung [Seonam Univ., Namwon (Korea, Republic of)

    2012-10-15

    The chemistry of electronically-excited phthalimides is dictated by electron and/or hydrogen transfer reactions. The photochemistry of phthalimides has been intensively studied, and numerous synthetically useful transformations with high chemical and quantum yields have been developed. 3 Among the synthetic applications, intra- and intermolecular photodecarboxylation (PDC) of ω-phthalimidoalkyl carboxylates has been developed by Griesbeck and coworkers as a versatile pathway to medium- and large-ring heterocycles. Model reactions were further realized on macro- and micro-scales. We recently described PDC cyclizations of ω-phthalimidoalkynoates to produce macrocyclic alkynes with ring-sizes up to 17. In recent study, we expanded the portfolio of this reaction and investigated the photochemistry of related aryl-linked phthalimides in Scheme 1. Based on these approaches, we demonstrated that ω-phthalimido-ortho/meta-phenoxy carboxylates undergo efficient PDC cyclizations. While the yields of ω-phthalimido-ortho-phenoxy carboxylates steadily decreased with increasing chain-length and the maximum yield of the 6-membered product was obtained in 75%, the yields of meta-phenoxy carboxylates steadily increased with increasing chain-length and the extended 16-membered product was subsequently obtained in 48% yield.

  2. SOCl 2 catalyzed cyclization of chalcones: Synthesis and spectral ...

    African Journals Online (AJOL)

    Some aryl-aryl 1H pyrazoles have been synthesised by cyclization of aryl chalcones and hydrazine hydrate in the presence of SOCl2. The yields of the pyrazoles are more than 85%. These pyrazoles are characterized by their physical constants and spectral data. The infrared, NMR spectral group frequencies of these ...

  3. Biosynthesis of monoterpenes: Stereochemistry of the coupled isomerization and cyclization of geranyl pyrophosphate to camphane and isocamphane monoterpenes

    International Nuclear Information System (INIS)

    Croteau, R.; Gershenzon, J.; Wheeler, C.J.; Satterwhite, D.M.

    1990-01-01

    The conversion of geranyl pyrophosphate to (+)-bornyl pyrophosphate and (+)-camphene is considered to proceed by the initial isomerization of the substrate to (-)-(3R)-linalyl pyrophosphate and the subsequent cyclization of this bound intermediate. In the case of (-)-bornyl pyrophosphate and (-)-camphene, isomerization of the substrate to the (+)-(3S)-linalyl intermediate precedes cyclization. The geranyl and linalyl precursors were shown to be mutually competitive substrates (inhibitors) of the relevant cyclization enzymes isolated from Salvia officinalis (sage) and Tanacetum vulgare (tansy) by the mixed substrate analysis method, demonstrating that isomerization and cyclization take place at the same active site. Incubation of partially purified enzyme preparations with (3R)-[1Z-3H]linalyl pyrophosphate plus [1-14C]geranyl pyrophosphate gave rise to double-labeled (+)-bornyl pyrophosphate and (+)-camphene, whereas incubation of enzyme preparations catalyzing the antipodal cyclizations with (3S)-[1Z-3H]-linalyl pyrophosphate plus [1-14C]geranyl pyrophosphate yielded double-labeled (-)-bornyl pyrophosphate and (-)-camphene. Each product was then transformed to the corresponding (+)- or (-)-camphor without change in the 3H:14C isotope ratio, and the location of the tritium label was deduced in each case by stereoselective, base-catalyzed exchange of the exo-alpha-hydrogen of the derived ketone. The finding that the 1Z-3H of the linalyl precursor was positioned at the endo-alpha-hydrogen of the corresponding camphor in all cases, coupled to the previously demonstrated retention of configuration at C1 of the geranyl substrate in these transformations, confirmed the syn-isomerization of geranyl pyrophosphate to linalyl pyrophosphate and the cyclization of the latter via the anti,endo- conformer

  4. A one-pot multistep cyclization yielding thiadiazoloimidazole derivatives

    Directory of Open Access Journals (Sweden)

    Debabrata Samanta

    2014-12-01

    Full Text Available A versatile synthetic procedure is described to prepare the benzimidazole-fused 1,2,4-thiadiazoles 2a–c via a methanesulfonyl chloride initiated multistep cyclization involving the intramolecular reaction of an in-situ generated carbodiimide with a thiourea unit. The structure of the intricate heterocycle 2a was confirmed by single-crystal X-ray analysis and its mechanism of formation supported by DFT computations.

  5. Utilizing redox-mediated Bergman cyclization toward the development of dual-action metalloenediyne therapeutics.

    Science.gov (United States)

    Lindahl, Sarah E; Park, Hyunsoo; Pink, Maren; Zaleski, Jeffrey M

    2013-03-13

    Reaction of 2 equiv of 1,2-bis((diphenylphosphino)ethynyl)benzene (dppeb, 1) with Pt(cod)Cl2 followed by treatment with N2H4 yields the reduced Pt(0) metalloenediyne, Pt(dppeb)2, 2. This complex is stable to both air oxidation and metal-mediated Bergman cyclization under ambient conditions due to the nearly idealized tetrahedral geometry. Reaction of 2 with 1 equiv of I2 in the presence of excess 1,4-cyclohexadiene (1,4-CHD) radical trap rapidly and near-quantitatively generates the cis-Bergman-cyclized, diiodo product 3 ((31)P: δ = 41 ppm, J(Pt-P) = 3346 Hz) with concomitant loss of 1 equiv of uncyclized phosphine chelate ((31)P: δ = -33 ppm). In contrast, addition of 2 equiv of I2 in the absence of additional radical trap instantaneously forms a metastable Pt(dppeb)2(2+) intermediate species, 4, that is characterized by δ = 51 ppm in the (31)P NMR (J(Pt-P) = 3171 Hz) and ν(C≡C) = 2169 cm(-1) in the Raman profile, indicating that it is an uncyclized, bis-ligated complex. Over 24 h, 4 undergoes ligand exchange to form a neutral, square planar complex that spontaneously Bergman cyclizes at ambient temperature to give the crystalline product Pt(dppnap-I2)I2 (dppnap-I2 = (1,4-diiodonaphthalene-2,3-diyl)bis(diphenylphosphine)), 5, in 52% isolated yield. Computational analysis of the oxidation reaction proposes two plausible flattened tetrahedral structures for intermediate 4: one where the phosphine core has migrated to a trans-spanning chelate geometry, and a second, higher energy structure (3.3 kcal/mol) with two cis-chelating phosphine ligands (41° dihedral angle) via a restricted alkyne-terminal starting point. While the energies are disparate, the common theme in both structures is the elongated Pt-P bond lengths (>2.4 Å), indicating that nucleophilic ligand substitution by I(-) is on the reaction trajectory to the cyclized product 5. The efficiency of the redox-mediated Bergman cyclization reaction of this stable Pt(0) metalloenediyne prodrug and

  6. 1,7-Cyclization of 1-diazo-2,4-pentadiene and its heteroanalogues: DFT study

    Science.gov (United States)

    Subbotina, Julia O.; Bakulev, V. A.; Herges, R.; Fabian, W. M. F.

    1,7-Dipolar cyclizations of 1-diazo-2,4-pentadiene 1a and its heteroanalogues 1b,c and 4c were studied using density functional theory (DFT). Although the heteroanalogue 1c has an appropriate electronic structure to allow for pseudopericyclic cyclization, natural bond order (NBO) analysis has provided evidence for the electrocyclic ring closure. Magnetic criteria (anisotropy of the induced current density [ACID], nucleus-independent chemical shifts [NICS]) confirmed the pericyclic character of the located transition states 2a,c and 5c. The activation barriers for the cyclization of 1-diazo-2,4-pentadiene 1a and its aza analogues 1c, 4c are 3.3, 8.2, and 12.3 kcal/mol at the B3LYP/6-31G(d) level, respectively. The higher barrier of the 1c?3c and 4c?3c reactions compared with 1a?3a is in line with the Hammond postulate. The out-of-plane distorted geometry of the cyclic product is an additional factor arguing against a pseudopericyclic mechanism.

  7. Parallel and four-step synthesis of natural-product-inspired scaffolds through modular assembly and divergent cyclization

    Directory of Open Access Journals (Sweden)

    Hiroki Oguri

    2012-06-01

    Full Text Available By emulating the universal biosynthetic strategy, which employs modular assembly and divergent cyclizations, we have developed a four-step synthetic process to yield a collection of natural-product-inspired scaffolds. Modular assembly of building blocks onto a piperidine-based manifold 6, having a carboxylic acid group, was achieved through Ugi condensation, N-acetoacetylation and diazotransfer, leading to cyclization precursors. The rhodium-catalyzed tandem cyclization and divergent cycloaddition gave rise to tetracyclic and hexacyclic scaffolds by the appropriate choice of dipolarophiles installed at modules 3 and 4. A different piperidine-based manifold 15 bearing an amino group was successfully applied to demonstrate the flexibility and scope of the unified four-step process for the generation of structural diversity in the fused scaffolds. Evaluation of in vitro antitrypanosomal activities of the collections and preliminary structure–activity relationship (SAR studies were also undertaken.

  8. Smooth isoindolinone formation from isopropyl carbamates via Bischler-Napieralski-type cyclization.

    Science.gov (United States)

    Adachi, Satoshi; Onozuka, Masao; Yoshida, Yuko; Ide, Mitsuaki; Saikawa, Yoko; Nakata, Masaya

    2014-01-17

    Isopropyl carbamates derived from benzylamines provide isoindolinones by treatment with phosphorus pentoxide at room temperature. Utility of this Bischler-Napieralski-type cyclization and a new mechanism involving a carbamoyl cation for rationalization of this smooth conversion are discussed.

  9. Direct Synthesis of Medium-Bridged Twisted Amides via a Transannular Cyclization Strategy

    Science.gov (United States)

    Szostak, Michal; Aubé, Jeffrey

    2009-01-01

    The sequential RCM to construct a challenging medium-sized ring followed by a transannular cyclization across a medium-sized ring delivers previously unattainable twisted amides from simple acyclic precursors. PMID:19708701

  10. Catalytic enantioselective alkene aminohalogenation/cyclization involving atom transfer.

    Science.gov (United States)

    Bovino, Michael T; Chemler, Sherry R

    2012-04-16

    Problem solved: the title reaction was used for the synthesis of chiral 2-bromo, chloro, and iodomethyl indolines and 2-iodomethyl pyrrolidines. Stereocenter formation is believed to occur by enantioselective cis aminocupration and C-X bond formation is believed to occur by atom transfer. The ultility of the products as versatile synthetic intermediates was demonstrated, as was a radical cascade cyclization sequence. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Synthesis of heterocyclic compounds through palladium-catalyzed C-H cyclization processes.

    Science.gov (United States)

    Inamoto, Kiyofumi

    2013-01-01

    Herein, we describe our development of synthetic methods for heterocyclic compounds based on the palladium-catalyzed carbon-hydrogen bond (C-H) functionalization/intramolecular carbon-heteroatom (nitrogen or sulfur) bond formation process. By this C-H cyclization method, we efficiently prepared various N-heterocycles, including indazoles, indoles, and 2-quinolinones, as well as S-heterocycles such as benzothiazoles and benzo[b]thiophenes. Yields are typically good to high and good functional-group tolerance is observed for each process, thereby indicating that the method provides a novel, highly applicable synthetic route to the abovementioned biologically important heterocyclic frameworks. As an application of this approach, an auto-tandem-type, one-pot process involving the oxidative Heck reaction and subsequent C-H cyclization using cinnamamides and arylboronic acids as starting materials in the presence of a palladium catalyst was also developed for the rapid construction of the 2-quinolinone nucleus.

  12. Heterocycles by Transition Metals Catalyzed Intramolecular Cyclization of Acetylene Compounds

    International Nuclear Information System (INIS)

    Vizer, S.A.; Yerzhanov, K.B.; Dedeshko, E.C.

    2003-01-01

    Review shows the new strategies in the synthesis of heterocycles, having nitrogen, oxygen and sulfur atoms, via transition metals catalyzed intramolecular cyclization of acetylenic compounds on the data published at the last 30 years, Unsaturated heterocyclic compounds (pyrroles and pyrroline, furans, dihydro furans and benzofurans, indoles and iso-indoles, isoquinolines and isoquinolinones, aurones, iso coumarins and oxazolinone, lactams and lactones with various substitutes in heterocycles) are formed by transition metals, those salts [PdCl 2 , Pd(OAc) 2 , HgCl 2 , Hg(OAc) 2 , Hg(OCOCF 3 ) 2 , AuCl 3 ·2H 2 O, NaAuCl 4 ·2H 2 O, CuI, CuCl], oxides (HgO) and complexes [Pd(OAc) 2 (PPh 3 )2, Pd(PPh 3 ) 4 , PdCl 2 (MeCN) 2 , Pd(OAc ) 2 /TPPTS] catalyzed intramolecular cyclization of acetylenic amines, amides, ethers, alcohols, acids, ketones and βdiketones. More complex hetero polycyclic systems typical for natural alkaloids can to obtain similar. Proposed mechanisms of pyrroles, isoquinolines, iso indoles and indoles, benzofurans and iso coumarins, thiazolopyrimidinones formation are considered. (author)

  13. Theoretical Study of Gold-Catalyzed Cyclization of 2-Alkynyl-N-propargylanilines and Rationalization of Kinetic Experimental Phenomena.

    Science.gov (United States)

    Duan, Yeqing; Liu, Yuxia; Bi, Siwei; Ling, Baoping; Jiang, Yuan-Ye; Liu, Peng

    2016-10-07

    Gold-catalyzed cyclization of 2-alkynyl-N-propargylanilines provides a step-economic method for the construction of three-dimensional indolines. In this article, the M06 functional of density functional theory was employed to gain deeper insights into the reaction mechanism and the associated intriguing experimental observations. The reaction was found to first undergo Au(I)-induced cyclization to form an indole intermediate, 1,3-propargyl migration, and substitution with the substrate 2-alkynyl-N-propargylaniline (R1) to generate the intermediate product P1, an allene species. Subsequently, Au(I)-catalyzed conversion of P1 into the final product P2, an indoline compound, occurs first through direct cyclization rather than via the previously proposed four-membered carbocycle intermediate. Thereafter, water-assisted oxygen heterocycle formation and proton transfer generate the final product. The calculated activation free energies indicate that P1 formation is 5.9 times slower than P2 formation, in accordance with the fact that P1 formation is rate-limiting. Futhermore, the intriguing experimental phenomenon that P2 can be accessed only after almost all the substrate R1 converts to P1 although P1 formation is rate-limiting was rationalized by employing an energetic span model. We found the initial facile cyclization to form a highly stable indole intermediate in the formation of P1 is the key to the intriguing experimental phenomenon.

  14. Cyclization of lapachol induced by thallium salts

    International Nuclear Information System (INIS)

    Ribeiro, Carlos Magno R.; Souza, Pablo P. de; Ferreira, Leticia L.D.M.; Pinto, Lia A.; Almeida, Leonardo S. de; Jesus, Janaina G. de

    2008-01-01

    This work describes the cyclization of lapachol (1) induced by thallium triacetate (TTA) and thallium trinitrate (TTN) in several solvents using magnetic stirring and under microwave irradiation. α-Xyloidone (2) - dehydro-a-lapachone - was obtained as the main product in these reactions in 20 - 75% yield. However, rhinacanthin-A (4) was isolated as main product in a 40% yield, using TTA and acetic anhydride:water (1:1) as solvent, and dehydroiso- a-lapachone (3) in 21% yield, using TTA and dichloromethane as solvent. The reaction time decreased drastically under microwave conditions, but the yields of these reactions were not the expected. (author)

  15. One-pot cascade michael.cyclization reactions of ο-hydroxycinnamaldehydes: Synthesis of functionalized 2,3-dihydrobenzofuranes

    Energy Technology Data Exchange (ETDEWEB)

    Gwon, Sung Hyuk; Kim, Sunggon [Kyonggi Univ., Suwon (Korea, Republic of)

    2012-04-15

    We described the cascade Michael.cyclization reaction of o-hydroxycinnamaldehydes with diethyl α-bromomalonate promoted by potassium carbonate. The reactions provided functionalized 2,3-dihydrobenzofurans in good yields for a variety of o-hydroxyaromatic α,β-unsaturated aldehydes. Current work focuses on expanding the scope of this reaction to other substrates such as sulfur yields, and on developing an efficient catalytic asymmetric variant. 2,3-Dihydrobenzofurans are found in numerous biologically active natural products and synthetic compounds. These are an attractive type of oxygenated compound because their basic core skeleton is present in neolignans, pterocarpans, and synthetic drugs used in the treatment of pulmonary hypertension, atherosclerotic peripheral arterial disease, and central nervous system trauma and ischemia. Owing to the importance of their structures, numerous synthetic methods for 2,3-dihydrobenzofurans have been developed, primarily: radical cyclizations, Lewis acid promoted reactions, anionic cyclizations, and transition-metal catalyzed processes. However, these methods cannot be generalized as much as is desirable, and they yielded poor chemo- and/or stereoselectivities. Hence, the development of an efficient enantioselective synthetic method for obtaining 2,3-dihydrobenzofuran scaffolds attracted our attention.

  16. One-pot cascade michael.cyclization reactions of ο-hydroxycinnamaldehydes: Synthesis of functionalized 2,3-dihydrobenzofuranes

    International Nuclear Information System (INIS)

    Gwon, Sung Hyuk; Kim, Sunggon

    2012-01-01

    We described the cascade Michael.cyclization reaction of o-hydroxycinnamaldehydes with diethyl α-bromomalonate promoted by potassium carbonate. The reactions provided functionalized 2,3-dihydrobenzofurans in good yields for a variety of o-hydroxyaromatic α,β-unsaturated aldehydes. Current work focuses on expanding the scope of this reaction to other substrates such as sulfur yields, and on developing an efficient catalytic asymmetric variant. 2,3-Dihydrobenzofurans are found in numerous biologically active natural products and synthetic compounds. These are an attractive type of oxygenated compound because their basic core skeleton is present in neolignans, pterocarpans, and synthetic drugs used in the treatment of pulmonary hypertension, atherosclerotic peripheral arterial disease, and central nervous system trauma and ischemia. Owing to the importance of their structures, numerous synthetic methods for 2,3-dihydrobenzofurans have been developed, primarily: radical cyclizations, Lewis acid promoted reactions, anionic cyclizations, and transition-metal catalyzed processes. However, these methods cannot be generalized as much as is desirable, and they yielded poor chemo- and/or stereoselectivities. Hence, the development of an efficient enantioselective synthetic method for obtaining 2,3-dihydrobenzofuran scaffolds attracted our attention

  17. An Intramolecular Heck reaction that Prefers a 5-endo- to a 6-exo-trig Cyclization Pathway

    DEFF Research Database (Denmark)

    Vital, Paulo; Norrby, Per-Ola; Tanner, David Ackland

    2006-01-01

    A regioselective aromatic Claisen rearrangement was used to prepare 17a, the precursor of triflate 17e. The intramolecular Heck reaction of 17e is promoted only by bidentate phosphine ligands, giving exclusively and in excellent yield 20, the product of a 5-endo-trig cyclization, despite the poss......A regioselective aromatic Claisen rearrangement was used to prepare 17a, the precursor of triflate 17e. The intramolecular Heck reaction of 17e is promoted only by bidentate phosphine ligands, giving exclusively and in excellent yield 20, the product of a 5-endo-trig cyclization, despite...

  18. Tandem Michael addition/radical cyclizations for the construction of highly functionalized cyclopentanes

    Czech Academy of Sciences Publication Activity Database

    Holan, Martin; Pohl, Radek; Císarová, I.; Jahn, Ullrich

    2012-01-01

    Roč. 106, - (2012), s1298-s1298 ISSN 0009-2770. [EuCheMS Chemistry Congress /4./. 26.08.2012-30.08.2012, Prague] Institutional research plan: CEZ:AV0Z40550506 Keywords : cyclization * diastereoselectivity * Michael addiction * radical reactions * domino reactions Subject RIV: CC - Organic Chemistry

  19. Highly Functionalized Cyclopentane Derivatives by Tandem Michael Addition/Radical Cyclization/Oxygenation Reactions

    Czech Academy of Sciences Publication Activity Database

    Holan, Martin; Pohl, Radek; Císařová, I.; Klepetářová, Blanka; Jones, P. G.; Jahn, Ullrich

    2015-01-01

    Roč. 21, č. 27 (2015), s. 9877-9888 ISSN 0947-6539 R&D Projects: GA ČR GA13-40188S Institutional support: RVO:61388963 Keywords : cyclization * domino reactions * electron transfer * Michael addition * radical reactions Subject RIV: CC - Organic Chemistry Impact factor: 5.771, year: 2015

  20. Recent Advances in Substrate-Controlled Asymmetric Cyclization for Natural Product Synthesis

    Directory of Open Access Journals (Sweden)

    Jeyun Jo

    2017-06-01

    Full Text Available Asymmetric synthesis of naturally occurring diverse ring systems is an ongoing and challenging research topic. A large variety of remarkable reactions utilizing chiral substrates, auxiliaries, reagents, and catalysts have been intensively investigated. This review specifically describes recent advances in successful asymmetric cyclization reactions to generate cyclic architectures of various natural products in a substrate-controlled manner.

  1. Modular Three-Component Synthesis of 4-Aminoquinolines via an Imidoylative Sonogashira/Cyclization Cascade

    NARCIS (Netherlands)

    Collet, Jurriën W.; Ackermans, Kelly; Lambregts, Jeffrey; Maes, Bert U.W.; Orru, Romano V.A.; Ruijter, Eelco

    2018-01-01

    We developed a one-pot, two-stage synthetic route to substituted 4-aminoquinolines involving an imidoylative Sonogashira coupling followed by acid-mediated cyclization. This three-component reaction affords pharmaceutically valuable 4-aminoquinolines in a one-pot procedure from readily available

  2. Hydroxyl-substituted ladder polyethers via selective tandem epoxidation/cyclization sequence.

    Science.gov (United States)

    Czabaniuk, Lara C; Jamison, Timothy F

    2015-02-20

    A new and highly selective method for the synthesis of hydroxyl-substituted tetrahydropyrans is described. This method utilizes titanium(IV) isopropoxide and diethyl tartrate to perform a diastereoselective epoxidation followed by in situ epoxide activation and highly selective endo-cyclization to form the desired tetrahydropyran ring. The HIJ ring fragment of the marine ladder polyether yessotoxin was synthesized using this two-stage tactic that proceeds with high efficiency and excellent regioselectivity.

  3. Enzyme-Like Catalysis of the Nazarov Cyclization by Supramolecular Encapsulation

    Energy Technology Data Exchange (ETDEWEB)

    Hastings, Courtney; Pluth, Michael; Bergman, Robert; Raymond, Kenneth

    2010-03-29

    A primary goal in the design and synthesis of molecular hosts has been the selective recognition and binding of a variety of guests using non-covalent interactions. Supramolecular catalysis, which is the application of such hosts towards catalysis, has much in common with many enzymatic reactions, chiefly the use of both spatially appropriate binding pockets and precisely oriented functional groups to recognize and activate specific substrate molecules. Although there are now many examples which demonstrate how selective encapsulation in a host cavity can enhance the reactivity of a bound guest, all have failed to reach the degree of increased reactivity typical of enzymes. We now report the catalysis of the Nazarov cyclization by a self-assembled coordination cage, a carbon-carbon bond-forming reaction which proceeds under mild, aqueous conditions. The acceleration in this system is over a million-fold, and represents the first example of supramolecular catalysis that achieves the level of rate enhancement comparable to that observed in several enzymes. We explain the unprecedented degree of rate increase as due to the combination of (a) preorganization of the encapsulated substrate molecule, (b) stabilization of the transition state of the cyclization by constrictive binding, and (c) increase in the basicity of the complexed alcohol functionality.

  4. Hydroxyl Radical-Mediated Novel Modification of Peptides: N-Terminal Cyclization through the Formation of α-Ketoamide.

    Science.gov (United States)

    Lee, Seon Hwa; Kyung, Hyunsook; Yokota, Ryo; Goto, Takaaki; Oe, Tomoyuki

    2015-01-20

    The hydroxyl radical-mediated oxidation of peptides and proteins constitutes a large group of post-translational modifications that can result in structural and functional changes. These oxidations can lead to hydroxylation, sulfoxidation, or carbonylation of certain amino acid residues and cleavage of peptide bonds. In addition, hydroxyl radicals can convert the N-terminus of peptides to an α-ketoamide via abstraction of the N-terminal α-hydrogen and hydrolysis of the ketimine intermediate. In the present study, we identified N-terminal cyclization as a novel modification mediated by a hydroxyl radical. The reaction of angiotensin (Ang) II (DRVYIHPF) and the hydroxyl radical generated by the Cu(II)/ascorbic acid (AA) system or UV/hydrogen peroxide system produced N-terminal cyclized-Ang II (Ang C) and pyruvamide-Ang II (Ang P, CH3COCONH-RVYIHPF). The structure of Ang C was confirmed by mass spectrometry and comparison to an authentic standard. The subsequent incubation of isolated Ang P in the presence of Cu(II)/AA revealed that Ang P was the direct precursor of Ang C. The proposed mechanism involves the formation of a nitrogen-centered (aminyl) radical, which cyclizes to form a five-membered ring containing the alkoxy radical. The subsequent β-scission reaction of the alkoxyl radical results in the cleavage of the terminal CH3CO group. The initial aminyl radical can be stabilized by chelation to the Cu(II) ions. The affinity of Ang C toward the Ang II type 1 receptor was significantly lower than that of Ang II or Ang P. Ang C was not further metabolized by aminopeptidase A, which converts Ang II to Ang III. Hydroxyl radical-mediated N-terminal cyclization was also observed in other Ang peptides containing N-terminal alanine, arginine, valine, and amyloid β 1-11 (DAEFRHDSGYE).

  5. Gold-Catalyzed Cyclizations of Alkynol-Based Compounds: Synthesis of Natural Products and Derivatives

    Directory of Open Access Journals (Sweden)

    Pedro Almendros

    2011-09-01

    Full Text Available The last decade has witnessed dramatic growth in the number of reactions catalyzed by gold complexes because of their powerful soft Lewis acid nature. In particular, the gold-catalyzed activation of propargylic compounds has progressively emerged in recent years. Some of these gold-catalyzed reactions in alkynes have been optimized and show significant utility in organic synthesis. Thus, apart from significant methodology work, in the meantime gold-catalyzed cyclizations in alkynol derivatives have become an efficient tool in total synthesis. However, there is a lack of specific review articles covering the joined importance of both gold salts and alkynol-based compounds for the synthesis of natural products and derivatives. The aim of this Review is to survey the chemistry of alkynol derivatives under gold-catalyzed cyclization conditions and its utility in total synthesis, concentrating on the advances that have been made in the last decade, and in particular in the last quinquennium.

  6. Synthesis of fused azole-piperidionoses: A free radical cyclization approach

    Energy Technology Data Exchange (ETDEWEB)

    Marco-Contelles, Jose; Alhambra Jimenez, Carolina [Instituto de Quimica Organica General (CSIC), Madrid (Spain)

    1999-08-01

    A new strategy has been reported for the synthesis of fused azole-piperidinoses featuring and unprecedented and very efficient 6-exo-trig free radical cyclization onto heterocyclic sugar templates. These compounds are key intermediates for the synthesis of known or analogues of azole-glycosidase inhibitors. In this communication we describe our recent and successful results on the synthesis of fused triazole-piperidinoses. Radical precursors have been prepared by standard methodologies from 1, 2:5, 6-bis-O-isopropylidene-{alpha}-D-glucofuranose (4) via triazoles linked at C3 with {beta}-orientation, readily obtained by 1, 3-dipolar cycloaddition of azide 5 with diethyl acetylenedicarboxylate or methyl propiolate, and by S{sub N}2 displacement of the tosylate at C3 with 1, 2, 4-triazole in compound 20. The key 6-exp-trig free radical cyclizations proceeded in the usual conditions [tributyltin hydride or tris(trimethylsily)silane, AIBN, toluene] yielding the azaannulated sugars 9, 11, 19 and 23 in good or excellent yields. A mechanism for these cyclizations has been proposed. [Spanish] Se ha informado una nueva estrategia para la sintesis azol-piperidinosas fusionadas mediante una ciclizacion 6-exo-trig muy eficiente y sin precedentes, sobre plantillas de azucares heterociclicos. Estos compuestos son intermediarios claves para la sintesis de inhibidores de azol-glicosidasa conocidos analogos de ellos. En esta comunicacion describimos nuestros resultados recientes y exitosos sobre la sintesis de triazol-piperidinosas. Los precursores de radicales fueron preparados por la metodologia usual a partir de 1, 2:5, 6-bis-O-isopropiliden-{alpha}-D-glucofuranosa (4) via triazoles unidos en C3, con orientacion {beta}, los cuales se obtienen facilmente por cicloadicion 1, 3-dipolar de la azida 5 con acetilendicarboxilato de dietilo o propiolato de metilo y por desplazamiento S{sub N}2 del tosilato en C3 con 1, 2, 4-triazol en el compuesto 20. Las ciclizaciones 6-exo

  7. Side Chain Cyclized Aromatic Amino Acids

    DEFF Research Database (Denmark)

    Van der Poorten, Olivier; Knuhtsen, Astrid; Sejer Pedersen, Daniel

    2016-01-01

    Constraining the conformation of flexible peptides is a proven strategy to increase potency, selectivity, and metabolic stability. The focus has mostly been on constraining the backbone dihedral angles; however, the correct orientation of the amino acid side chains (χ-space) that constitute...... the peptide pharmacophore is equally important. Control of χ-space utilizes conformationally constrained amino acids that favor, disfavor, or exclude the gauche (-), the gauche (+), or the trans conformation. In this review we focus on cyclic aromatic amino acids in which the side chain is connected...... to the peptide backbone to provide control of χ(1)- and χ(2)-space. The manifold applications for cyclized analogues of the aromatic amino acids Phe, Tyr, Trp, and His within peptide medicinal chemistry are showcased herein with examples of enzyme inhibitors and ligands for G protein-coupled receptors....

  8. Gold(I-catalyzed domino cyclization for the synthesis of polyaromatic heterocycles

    Directory of Open Access Journals (Sweden)

    Mathieu Morin

    2013-11-01

    Full Text Available Gold(I complexes have emerged as powerful and useful catalysts for the formation of new C–C, C–O and C–N bonds. Taking advantage of the specificity of [IPrAuNCMe][SbF6] complexes to favor the 5-exo-dig cyclization over the 6-endo-dig pathway, we report a high yielding and efficient method to generate substituted polyaromatic heterocycles under remarkably mild reaction conditions.

  9. Synthesis, Characterization, and In Vitro Evaluation of New (99m)Tc/Re(V)-Cyclized Octreotide Analogues: An Experimental and Computational Approach.

    Science.gov (United States)

    Li, Yawen; Ma, Lixin; Gaddam, Vikram; Gallazzi, Fabio; Hennkens, Heather M; Harmata, Michael; Lewis, Michael R; Deakyne, Carol A; Jurisson, Silvia S

    2016-02-01

    Radiolabeled proteolytic degradation-resistant somatostatin analogues have been of long-standing interest as cancer imaging and radiotherapy agents for targeting somatostatin receptor-positive tumors. Our interest in developing (186)Re- and (188)Re-based therapeutic radiopharmaceuticals led to investigation of a new Re(V)-cyclized octreotide analogue, Re(V)-cyclized, thiolated-DPhe(1)-Cys(2)-Tyr(3)-DTrp(4)-Lys(5)-Thr(6)-Cys(7)-Thr(OH)(8) (Re-SDPhe-TATE) using both experimental and quantum chemical methods. The metal is directly coordinated to SDPhe-TATE through cyclization of the peptide around the [ReO](3+) core. Upon complexation, four isomers were observed; the isolated/semi-isolated isomers exhibited different somatostatin receptor (sstr) binding affinities, 0.13 to 1.5 μM, in rat pancreatic tumor cells. Two-dimensional NMR experiments and electronic structure calculations were employed to elucidate the structural differences among the different isomers. According to NMR studies, the metal is coordinated to three thiolates and the backbone amide of Cys(2) in isomers 1 and 4, whereas the metal is coordinated to three thiolates and the backbone amide of Tyr(3) in isomer 2. Quantum chemical methods clarified the stereochemistry of Re-SDPhe-TATE and the possible peptide arrangements around the [ReO](3+) core. The re-cyclization reaction was translated to the (99m)Tc radiotracer level with four isomers observed on complexation with comparable HPLC retention times as the Re-SDPhe-TATE isomers. About 85% total (99m)Tc labeling yield was achieved by ligand exchange from (99m)Tc-glucoheptonate at 60 °C for an hour. About 100% and 51% of (99m)Tc(V)-cyclized SDPhe-TATE remained intact in phosphate buffered saline and 1 mM cysteine solution under physiological conditions at 6 h, respectively.

  10. Green chemistry: solvent- and metal-free Prins cyclization. Application to sequential reactions.

    Science.gov (United States)

    Clarisse, Damien; Pelotier, Béatrice; Piva, Olivier; Fache, Fabienne

    2012-01-04

    Prins cyclization between a homoallylic alcohol and an aldehyde, promoted by trimethylsilyl halide, afforded 4-halo-tetrahydropyrans with good to excellent yields. Thanks to the absence of the solvent and metal, the THP thus obtained have been implicated without purification in several other reactions, in a sequential way, affording in particular new indole derivatives. This journal is © The Royal Society of Chemistry 2012

  11. Potassium hydroxide/dimethyl sulfoxide promoted intramolecular cyclization for the synthesis of benzimidazol-2-ones.

    Science.gov (United States)

    Beyer, Astrid; Reucher, Christine M M; Bolm, Carsten

    2011-06-03

    A new protocol for intramolecular N-arylations of ureas to form benzimidazol-2-ones has been developed. The cyclization reaction occurs in the presence of KOH and DMSO at close to ambient temperature. Under these conditions the yields are high and a wide range of functional groups are tolerated.

  12. Facile synthesis of benzofurans via copper-catalyzed aerobic oxidative cyclization of phenols and alkynes.

    Science.gov (United States)

    Zeng, Wei; Wu, Wanqing; Jiang, Huanfeng; Huang, Liangbin; Sun, Yadong; Chen, Zhengwang; Li, Xianwei

    2013-07-28

    Regioselective synthesis of polysubstituted benzofurans using a copper catalyst and molecular oxygen from phenols and alkynes in a one-pot procedure has been reported. The transformation consists of a sequential nucleophilic addition of phenols to alkynes and oxidative cyclization. A wide variety of phenols and alkynes can be used in the same manner.

  13. Nickel-catalyzed cyclization of alpha, omega-dienes: formation vs. cleavage of C-C bonds

    Czech Academy of Sciences Publication Activity Database

    Nečas, D.; Turský, M.; Tišlerová, I.; Kotora, Martin

    2006-01-01

    Roč. 30, č. 4 (2006), s. 671-674 ISSN 1144-0546 R&D Projects: GA MŠk 1M0508; GA ČR GD203/03/H140 Institutional research plan: CEZ:AV0Z40550506 Keywords : catalysis * nickel * cyclization * diene * cyclopentane Subject RIV: CC - Organic Chemistry Impact factor: 2.647, year: 2006

  14. Asymmetric Construction of Benzindoloquinolizidine: Application of An Organocatalytic Enantioselective Conjugate Addition-Cyclization Cascade Reaction

    International Nuclear Information System (INIS)

    Kim, Cheolwoong; Seo, Seung Woo; Lee, Yona; Kim, Sunggon

    2014-01-01

    We have developed the synthetic methodology of enantioenriched benzindoloquinolizidines based on the organocatalytic enantioselective conjugate addition-cyclization cascade reaction of o-N-(3-indoleacetyl)amino-cinnamaldehydes with malonates followed by an acid-catalyzed intramolecular Pictet-Spengler type cyclization. The asymmetric reaction using diphenylprolinol TMS ether as an organocatalyst produces the desired products with good to excellent yields and high enantioselectivities (up to 98% ee). The evaluation of the applications of this synthetic methodology for generating enantioenriched benzindolo-quinolizidines and studies on the biological activity of these compounds against human prostate cancer in particular are now in progress. Results of these studies will be presented in due course. Many new types of chemical reactions have been developed to facilitate easier synthesis of complex compounds. Among the strategies, domino reactions, which have been utilized for the efficient and stereoselective construction of complex molecules from simple precursors in a single process, are widely used due to their high synthetic efficiency by reducing both the number of synthetic operation required and the quantities of chemicals and solvents used

  15. Dissociation of protonated N-(3-phenyl-2H-chromen-2-ylidene)-benzenesulfonamide in the gas phase: cyclization via sulfonyl cation transfer.

    Science.gov (United States)

    Wang, Shanshan; Dong, Cheng; Yu, Lian; Guo, Cheng; Jiang, Kezhi

    2016-01-15

    In the tandem mass spectrometry of protonated N-(3-phenyl-2H-chromen-2-ylidene)benzenesulfonamides, the precursor ions have been observed to undergo gas-phase dissociation via two competing channels: (a) the predominant channel involves migration of the sulfonyl cation to the phenyl C atom and the subsequent loss of benzenesulfinic acid along with cyclization reaction, and (b) the minor one involves dissociation of the precursor ion to give an ion/neutral complex of [sulfonyl cation/imine], followed by decomposition to afford sulfonyl cation or the INC-mediated electron transfer to give an imine radical cation. The proposed reaction channels have been supported by theoretical calculations and D-labeling experiments. The gas-phase cyclization reaction originating from the N- to C-sulfonyl cation transfer has been first reported to the best of our knowledge. For the substituted sulfonamides, the presence of electron-donating groups (R(2) -) at the C-ring effectively facilitates the reaction channel of cyclization reaction, whereas that of electron-withdrawing groups inhibits this pathway. Copyright © 2015 John Wiley & Sons, Ltd.

  16. Electrooxidative Tandem Cyclization of Activated Alkynes with Sulfinic Acids To Access Sulfonated Indenones

    Energy Technology Data Exchange (ETDEWEB)

    Wen, Jiangwei [The; Center; Shi, Wenyan [The; Zhang, Fan [The; Liu, Dong [The; Tang, Shan [The; Wang, Huamin [The; Lin, Xiao-Min [Center; Lei, Aiwen [The

    2017-05-25

    An,electrooxidative direct arylsulfonlylation of yones sulfintc acids via a radical tandem cyclization strategy has been developed for the construction of sulfonated ilicIenones:under oxidant, free conditions. This method provides a simple and efficient approach to prepare various sulfonylindenones in good to,excellent:Tyidds,, demonstrating the tremendous prospect of utilizing electrocatalysis in oxidative coupling, Notably, this reaction could Be easily scaled up with good, efficiency.

  17. Tandem electrophilic cyclization-[3+2] cycloaddition-rearrangement reactions of 2-alkynylbenzaldoxime, DMAD, and Br2.

    Science.gov (United States)

    Ding, Qiuping; Wang, Zhiyong; Wu, Jie

    2009-01-16

    Tandem electrophilic cyclization-[3+2] cycloaddition-rearrangement reactions of 2-alkynylbenzaldoximes, DMAD, and bromine are described, which afford the unexpected isoquinoline-based azomethine ylides in good to excellent yields. The products could be further elaborated via palladium-catalyzed cross-coupling reactions to generate highly functionalized isoquinoline-based stable azomethine ylides.

  18. Pd-Catalyzed C-H activation/oxidative cyclization of acetanilide with norbornene: concise access to functionalized indolines.

    Science.gov (United States)

    Gao, Yang; Huang, Yubing; Wu, Wanqing; Huang, Kefan; Jiang, Huanfeng

    2014-08-07

    An efficient Pd-catalyzed oxidative cyclization reaction for the synthesis of functionalized indolines by direct C-H activation of acetanilide has been developed. The norbornylpalladium species formed via direct ortho C-H activation of acetanilides is supposed to be a key intermediate in this transformation.

  19. Catalytic stereoselective synthesis of highly substituted indanones via tandem Nazarov cyclization and electrophilic fluorination trapping.

    Science.gov (United States)

    Nie, Jing; Zhu, Hong-Wei; Cui, Han-Feng; Hua, Ming-Qing; Ma, Jun-An

    2007-08-02

    A new catalytic stereoselective tandem transformation via Nazarov cyclization/electrophilic fluorination has been accomplished. This sequence is efficiently catalyzed by a Cu(II) complex to afford fluorine-containing 1-indanone derivatives with two new stereocenters with high diastereoselectivity (trans/cis up to 49/1). Three examples of catalytic enantioselective tandem transformation are presented.

  20. Synthesis of benzimidazoles by potassium tert-butoxide-promoted intermolecular cyclization reaction of 2-iodoanilines with nitriles.

    Science.gov (United States)

    Xiang, Shi-Kai; Tan, Wen; Zhang, Dong-Xue; Tian, Xian-Li; Feng, Chun; Wang, Bi-Qin; Zhao, Ke-Qing; Hu, Ping; Yang, Hua

    2013-11-14

    The synthesis of benzimidazoles by intermolecular cyclization reaction of 2-iodoanilines with nitriles has been developed. These reactions proceeded without the aid of any transition metals or ligands and just using KOBu(t) as the base. A variety of substituted benzimidazole derivatives can be synthesized by the approach.

  1. Ascorbic Acid-Initiated Tandem Radical Cyclization of N-Arylacrylamides to Give 3,3-Disubstituted Oxindoles

    Directory of Open Access Journals (Sweden)

    Sheng Liu

    2015-08-01

    Full Text Available An ascorbic acid-promoted and metal-free tandem room temperature cyclization of N-arylacrylamides with 4-nitrobenzenediazonium generated in situ was developed. This reaction proceeds smoothly through a radical mechanism and provides an environmentally friendly alternative approach to biologically active 3-alkyl-3-benzyloxindoles, avoiding the use of excess oxidants and light irradiation.

  2. Development of the Vinylogous Pictet-Spengler Cyclization and Total Synthesis of (±)-Lundurine A.

    Science.gov (United States)

    Nash, Aaron; Qi, Xiangbing; Maity, Pradip; Owens, Kyle; Tambar, Uttam K

    2018-04-16

    A novel vinylogous Pictet-Spengler cyclization has been developed for the generation of indole-annulated medium-sized rings. The method enables the synthesis of tetrahydroazocinoindoles with a fully substituted carbon center, a prevalent structural motif in many biologically active alkaloids. The strategy has been applied to the total synthesis of (±)-lundurine A. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Synthesis of 1-(2-Ethynyl-6-methylphenyl)- and 1-(2-Ethynyl-6-methoxyphenyl)-Naphthalene and Their Cyclization

    Czech Academy of Sciences Publication Activity Database

    Storch, Jan; Čermák, Jan; Karban, Jindřich

    2007-01-01

    Roč. 48, č. 38 (2007), s. 6814-6816 ISSN 0040-4039 R&D Projects: GA MŠk(CZ) LC06070 Institutional research plan: CEZ:AV0Z40720504 Keywords : aromate * cyclization * cycloizomerization Subject RIV: CC - Organic Chemistry Impact factor: 2.615, year: 2007

  4. The Suzuki–Miyaura Cross-Coupling as a Versatile Tool for Peptide Diversification and Cyclization

    Directory of Open Access Journals (Sweden)

    Tom Willemse

    2017-02-01

    Full Text Available The (site-selective derivatization of amino acids and peptides represents an attractive field with potential applications in the establishment of structure–activity relationships and labeling of bioactive compounds. In this respect, bioorthogonal cross-coupling reactions provide valuable means for ready access to peptide analogues with diversified structure and function. Due to the complex and chiral nature of peptides, mild reaction conditions are preferred; hence, a suitable cross-coupling reaction is required for the chemical modification of these challenging substrates. The Suzuki reaction, involving organoboron species, is appropriate given the stability and environmentally benign nature of these reactants and their amenability to be applied in (partial aqueous reaction conditions, an expected requirement upon the derivatization of peptides. Concerning the halogenated reaction partner, residues bearing halogen moieties can either be introduced directly as halogenated amino acids during solid-phase peptide synthesis (SPPS or genetically encoded into larger proteins. A reversed approach building in boron in the peptidic backbone is also possible. Furthermore, based on this complementarity, cyclic peptides can be prepared by halogenation, and borylation of two amino acid side chains present within the same peptidic substrate. Here, the Suzuki–Miyaura reaction is a tool to induce the desired cyclization. In this review, we discuss diverse amino acid and peptide-based applications explored by means of this extremely versatile cross-coupling reaction. With the advent of peptide-based drugs, versatile bioorthogonal conversions on these substrates have become highly valuable.

  5. Expedient pyrrolizidine synthesis by propargylsilane addition to N-acyliminium ions followed by gold-catalyzed α-allenyl amide cyclization

    NARCIS (Netherlands)

    Breman, A.C.; Dijkink, J.; van Maarseveen, J.H.; Kinderman, S.S.; Hiemstra, H.

    2009-01-01

    A reaction sequence, involving the addition of (substituted) propargylsilanes to lactate-derived N-acyliminium ions followed by gold-catalyzed cyclization of the resulting alpha-allenyl amide, is applied in expedient syntheses of pyrrolizidine alkaloids heliotridine and ent-retronecine in five steps

  6. Total Syntheses of Polycyclic Polyprenylated Acylphloroglucinol Natural Products and Analogs Utilizing Alkylative Dearomatizations and Cationic Cyclizations

    Science.gov (United States)

    Boyce, Jonathan H.

    Polycyclic polyprenylated acylphloroglucinols (PPAPs) are structurally complex natural products with promising biological activities. These compounds have interesting anticancer and anti-HIV properties as well as other biological activities making them highly attractive synthetic targets. We report a stereodivergent, asymmetric total synthesis of (-)-clusianone in six steps from commercial materials. We have implemented a challenging cationic cyclization forging a bond between two sterically encumbered quaternary carbon atoms. Mechanistic studies point to the unique ability of formic acid to mediate the cyclization forming the clusianone framework. We also present a biosynthesis-inspired, diversity-oriented synthesis approach for rapid construction of PPAP analogs via palladium-catalyzed dearomative conjunctive allylic alkylation (DCAA). These efficient palladium-catalyzed protocols construct the [3.3.1]-bicyclic PPAP core in a single step from their stable aromatic precursors. The first syntheses of 13,14-didehydroxyisogarcinol and garcimultiflorone A stereoisomers are reported in six steps from a commercially available phloroglucinol. Lewis acid-controlled, diastereoselective cationic oxycyclizations enabled asymmetric syntheses of (-)-6-epi-13,14-didehydroxyisogarcinol and (+)-30-epi-13,14-didehydroxyisogarcinol. A similar strategy enabled production of the meso-derived isomers (+/-)-6,30- epi-13,14-didehydroxyisogarcinol and (+/-)-6,30-epi -garcmultiflorone A. A convenient strategy for gram scale synthesis of these stereoisomers was developed utilizing diastereomer separation at a later stage in the synthesis that minimized the number of necessary synthetic operations to access all possible stereoisomers. Finally, we report cationic rearrangements of dearomatized acylphloroglucinols leading to the formation of unprecedented PPAP scaffolds. A novel type A [3.3.1]-bicyclic PPAP was produced as a major product and the structure confirmed by X-ray crystallographic

  7. N,2,3,4-Tetrasubstituted Pyrrolidines through Tandem Lithium Amide Conjugate Addition/Radical Cyclization/Oxygenation Reactions

    Czech Academy of Sciences Publication Activity Database

    Kafka, František; Pohl, Radek; Císařová, I.; Mackman, R.; Bahador, G.; Jahn, Ullrich

    2016-01-01

    Roč. 2016, č. 22 (2016), s. 3862-3871 ISSN 1434-193X R&D Projects: GA ČR GA13-40188S Grant - others:COST(XE) CM1201 Institutional support: RVO:61388963 Keywords : tandem reactions * nitrogen heterocycles * Michael addition * radical reactions * cyclization * enolates Subject RIV: CC - Organic Chemistry Impact factor: 2.834, year: 2016

  8. The direct oxidative diene cyclization and related reactions in natural product synthesis

    Directory of Open Access Journals (Sweden)

    Juliane Adrian

    2016-09-01

    Full Text Available The direct oxidative cyclization of 1,5-dienes is a valuable synthetic method for the (diastereoselective preparation of substituted tetrahydrofurans. Closely related reactions start from 5,6-dihydroxy or 5-hydroxyalkenes to generate similar products in a mechanistically analogous manner. After a brief overview on the history of this group of transformations and a survey on mechanistic and stereochemical aspects, this review article provides a summary on applications in natural product synthesis. Moreover, current limitations and future directions in this area of chemistry are discussed.

  9. Reversal of Hartmann's procedure following acute diverticulitis: is timing everything?

    LENUS (Irish Health Repository)

    Fleming, Fergal J

    2012-02-01

    BACKGROUND: Patients who undergo a Hartmann\\'s procedure may not be offered a reversal due to concerns over the morbidity of the second procedure. The aims of this study were to examine the morbidity post reversal of Hartmann\\'s procedure. METHODS: Patients who underwent a Hartmann\\'s procedure for acute diverticulitis (Hinchey 3 or 4) between 1995 and 2006 were studied. Clinical factors including patient comorbidities were analysed to elucidate what preoperative factors were associated with complications following reversal of Hartmann\\'s procedure. RESULTS: One hundred and ten patients were included. Median age was 70 years and 56% of the cohort were male (n = 61). The mortality and morbidity rate for the acute presentation was 7.3% (n = 8) and 34% (n = 37) respectively. Seventy six patients (69%) underwent a reversal at a median of 7 months (range 3-22 months) post-Hartmann\\'s procedure. The complication rate in the reversal group was 25% (n = 18). A history of current smoking (p = 0.004), increasing time to reversal (p = 0.04) and low preoperative albumin (p = 0.003) were all associated with complications following reversal. CONCLUSIONS: Reversal of Hartmann\\'s procedure can be offered to appropriately selected patients though with a significant (25%) morbidity rate. The identification of potential modifiable factors such as current smoking, prolonged time to reversal and low preoperative albumin may allow optimisation of such patients preoperatively.

  10. Improving the stability of alpha-conotoxin AuIB through N-to-C cyclization

    DEFF Research Database (Denmark)

    Armishaw, Christopher J; Jensen, Anders A; Balle, Lena D

    2011-01-01

    Modification of alpha-conotoxin frameworks through cyclization via an oligopeptide linker has previously been shown as an effective strategy for improving in vivo stability. We have extended this strategy by investigating cyclic analogs of alpha-conotoxin AuIB, a selective alpha3beta4 nicotinic a......-AuIB. As such, the cAuIB-2 globular isomer could constitute a useful probe for studying the role of the alpha3beta4 nicotinic acetylcholine receptor in a range of in vivo experimental paradigms....

  11. Synthesis of Heterocycles through a Ruthenium‐Catalyzed Tandem Ring‐Closing Metathesis/Isomerization/N‐Acyliminium Cyclization Sequence

    DEFF Research Database (Denmark)

    Ascic, Erhad; Jensen, Jakob Feldthusen; Nielsen, Thomas Eiland

    2011-01-01

    Tandem bicycle: In the title reaction double bonds created during ring-closing metathesis isomerize to generate reactive iminium intermediates that undergo intramolecular cyclization reactions with tethered heteroatom and carbon nucleophiles. In this way, a series of biologically interesting hete...... heterocyclic compounds can be made, including a known precursor for the total synthesis of the antiparasitic natural product harmicine....

  12. Post-Ugi gold-catalyzed diastereoselective domino cyclization for the synthesis of diversely substituted spiroindolines

    Directory of Open Access Journals (Sweden)

    Amit Kumar

    2013-10-01

    Full Text Available An Ugi four-component reaction of propargylamine with 3-formylindole and various acids and isonitriles produces adducts which are subjected to a cationic gold-catalyzed diastereoselective domino cyclization to furnish diversely substituted spiroindolines. All the reactions run via an exo-dig attack in the hydroarylation step followed by an intramolecular diastereoselective trapping of the imminium ion. The whole sequence is atom economic and the application of a multicomponent reaction assures diversity.

  13. Eosin Y-catalyzed visible-light-mediated aerobic oxidative cyclization of N,N-dimethylanilines with maleimides.

    Science.gov (United States)

    Liang, Zhongwei; Xu, Song; Tian, Wenyan; Zhang, Ronghua

    2015-01-01

    A novel and simple strategy for the efficient synthesis of the corresponding tetrahydroquinolines from N,N-dimethylanilines and maleimides using visible light in an air atmosphere in the presence of Eosin Y as a photocatalyst has been developed. The metal-free protocol involves aerobic oxidative cyclization via sp(3) C-H bond functionalization process to afford good yields in a one-pot procedure under mild conditions.

  14. Reverse-hybrid robotic mesorectal excision for rectal cancer.

    Science.gov (United States)

    Park, In Ja; You, Y Nancy; Schlette, Erika; Nguyen, Sa; Skibber, John M; Rodriguez-Bigas, Miguel A; Chang, George J

    2012-02-01

    The robotic system offers potential technical advantages over laparoscopy for total mesorectal excision with radical lymphadenectomy for rectal cancer. However, the requirement for fixed docking limits its utility when the working volume is large or patient repositioning is required. The purpose of this study was to evaluate short-term outcomes associated with a novel setup to perform total mesorectal excision and radical lymphadenectomy for rectal cancer by the use of a "reverse" hybrid robotic-laparoscopic approach. This is a prospective consecutive cohort observational study of patients who underwent robotic rectal cancer resection from January 2009 to March 2011. During the study period, a technique of reverse-hybrid robotic-laparoscopic rectal resection with radical lymphadenectomy was developed. This technique involves reversal of the operative sequence with lymphovascular and rectal dissection to precede proximal colonic mobilization. This technique evolved from a conventional-hybrid resection with laparoscopic vascular control, colonic mobilization, and robotic pelvic dissection. Perioperative and short-term oncologic outcomes were analyzed. Thirty patients underwent reverse-hybrid resection. Median tumor location was 5 cm (interquartile range 3-9) from the anal verge. Median BMI was 27.6 (interquartile range 25.0-32.1 kg/m). Twenty (66.7%) received neoadjuvant chemoradiation. There were no conversions. Median blood loss was 100 mL (interquartile range 75-200). Total operation time was a median 369 (interquartile range 306-410) minutes. Median docking time was 6 (interquartile range 5-8) minutes, and console time was 98 (interquartile range 88-140) minutes. Resection was R0 in all patients; no patients had an incomplete mesorectal resection. Six patients (20%) underwent extended lymph node dissection or en bloc resection. Reverse-hybrid robotic surgery for rectal cancer maximizes the therapeutic applicability of the robotic and conventional laparoscopic

  15. Eosin Y-catalyzed visible-light-mediated aerobic oxidative cyclization of N,N-dimethylanilines with maleimides

    Directory of Open Access Journals (Sweden)

    Zhongwei Liang

    2015-04-01

    Full Text Available A novel and simple strategy for the efficient synthesis of the corresponding tetrahydroquinolines from N,N-dimethylanilines and maleimides using visible light in an air atmosphere in the presence of Eosin Y as a photocatalyst has been developed. The metal-free protocol involves aerobic oxidative cyclization via sp3 C–H bond functionalization process to afford good yields in a one-pot procedure under mild conditions.

  16. Biosynthesis of monoterpenes. Stereochemistry of the enzymatic cyclizations of geranyl pyrophosphate to (+)-alpha-pinene and (-)-beta-pinene

    International Nuclear Information System (INIS)

    Croteau, R.; Satterwhite, D.M.; Wheeler, C.J.; Felton, N.M.

    1989-01-01

    The conversion of geranyl pyrophosphate to (+)-alpha-pinene and to (-)-beta-pinene is considered to proceed by the initial isomerization of the substrate to (-)-(3R)- and to (+)-(3S)-linalyl pyrophosphate, respectively, and the subsequent cyclization of the anti, endo-conformer of these bound intermediates by mirror-image sequences which should result in the net retention of configuration at C1 of the geranyl precursor. Incubation of (1R)-[2-14C,1-3H]- and (1S)-[2-14C,1-3H]geranyl pyrophosphate with (+)-pinene cyclase and with (-)-pinene cyclase from common sage (Salvia officinalis) gave labeled (+)-alpha- and (-)-beta-pinene of unchanged 3H/14C ratio in all cases, and the (+)- and (-)-olefins were stereoselectively converted to (+)- and (-)-borneol, respectively, which were oxidized to the corresponding (+)- and (-)-isomers of camphor, again without change in isotope ratio. The location of the tritium was determined in each case by stereoselective, base-catalyzed exchange of the exo-alpha-hydrogens of these derived ketones. The results indicated that the configuration at C1 of the substrate was retained in the enzymatic transformations to the (+)- and (-)-pinenes, which is entirely consistent with the syn-isomerization of geranyl pyrophosphate to linalyl pyrophosphate, transoid to cisoid rotation, and anti, endo-cyclization of the latter. The absolute stereochemical elements of the antipodal reaction sequences were confirmed by the selective enzymatic conversions of (3R)- and (3S)-1Z-[1-3H]linalyl pyrophosphate to (+)-alpha-pinene and (-)-beta-pinene, respectively, and by the location of the tritium in the derived camphors as before. The summation of the results fully defines the overall stereochemistry of the coupled isomerization and cyclization of geranyl pyrophosphate to the antipodal pinenes

  17. Oxidative radical cyclizations of diketopiperazines bearing an amidomalonate unit. Heterointermediate reaction sequences toward the asperparalines and stephacidins

    Czech Academy of Sciences Publication Activity Database

    Amatov, Tynchtyk; Gebauer, Martin; Pohl, Radek; Císařová, I.; Jahn, Ullrich

    2016-01-01

    Roč. 50, Suppl 1 (2016), S6-S17 ISSN 1071-5762 Grant - others:COST(XE) CM1201 Institutional support: RVO:61388963 Keywords : alkaloids * diketopiperazines * radical cyclizations * single electron transfer * oxidation Subject RIV: CC - Organic Chemistry Impact factor: 3.188, year: 2016 http://www.tandfonline.com/doi/full/10.1080/10715762.2016.1223295

  18. Gold(I)-catalyzed diazo cross-coupling: a selective and ligand-controlled denitrogenation/cyclization cascade.

    Science.gov (United States)

    Xu, Guangyang; Zhu, Chenghao; Gu, Weijin; Li, Jian; Sun, Jiangtao

    2015-01-12

    An unprecedented gold-catalyzed ligand-controlled cross-coupling of diazo compounds by sequential selective denitrogenation and cyclization affords N-substituted pyrazoles in a position-switchable mode. This novel transformation features selective decomposition of one diazo moiety and simultaneous preservation of the other one from two substrates. Notably, the choice of the ancillary ligand to the gold complex plays a pivotal role on the chemo- and regioselectivity of the reactions. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Biosynthesis of monoterpenes. Enantioselectivity in the enzymatic cyclization of (+)- and (-)-linalyl pyrophosphate to (+)- and (-)-pinene and (+)- and (-)-camphene

    International Nuclear Information System (INIS)

    Croteau, R.; Satterwhite, D.M.; Cane, D.E.; Chang, C.C.

    1988-01-01

    Cyclase I from Salvia officinalis leaf catalyzes the conversion of geranyl pyrophosphate to the stereo-chemically related bicyclic monoterpenes (+)-alpha-pinene and (+)-camphene and to lesser quantities of monocyclic and acyclic olefins, whereas cyclase II from this plant tissue converts the same acyclic precursor to (-)-alpha-pinene, (-)-beta-pinene and (-)-camphene as well as to lesser amounts of monocyclics and acyclics. These antipodal cyclizations are considered to proceed by the initial isomerization of the substrate to the respective bound tertiary allylic intermediates (-)-(3R)- and (+)-(3S)-linalyl pyrophosphate. [(3R)-8,9-14C,(3RS)-1E-3H]Linalyl pyrophosphate (3H:14C = 5.14) was tested as a substrate with both cyclases to determine the configuration of the cyclizing intermediate. This substrate with cyclase I yielded alpha-pinene and camphene with 3H:14C ratios of 3.1 and 4.2, respectively, indicating preferential, but not exclusive, utilization of the (3R)-enantiomer. With cyclase II, the doubly labeled substrate gave bicyclic olefins with 3H:14C ratios of from 13 to 20, indicating preferential, but not exclusive, utilization of the (3S)-enantiomer in this case. (3R)- and (3S)-[1Z-3H]linalyl pyrophosphate were separately compared to the achiral precursors [1-3H]geranyl pyrophosphate and [1-3H]neryl pyrophosphate (cis-isomer) as substrates for the cyclizations. With cyclase I, geranyl, neryl, and (3R)-linalyl pyrophosphate gave rise exclusively to (+)-alpha-pinene and (+)-camphene, whereas (3S)-linayl pyrophosphate produced, at relatively low rates, the (-)-isomers. With cyclase II, geranyl, neryl, and (3S)-linalyl pyrophosphate yielded exclusively the (-)-isomer series, whereas (3R)-linalyl pyrophosphate afforded the (+)-isomers at low rates

  20. 111In-labeled lactam bridge-cyclized alpha-melanocyte stimulating hormone peptide analogues for melanoma imaging.

    Science.gov (United States)

    Miao, Yubin; Gallazzi, Fabio; Guo, Haixun; Quinn, Thomas P

    2008-02-01

    The purpose of this study was to examine the influence of the lactam bridge cyclization on melanoma targeting and biodistribution properties of the radiolabeled conjugates. Two novel lactam bridge-cyclized alpha-MSH peptide analogues, DOTA-CycMSH (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid-c[Lys-Nle-Glu-His-DPhe-Arg-Trp-Gly-Arg-Pro-Val-Asp]) and DOTA-GlyGlu-CycMSH (DOTA-Gly-Glu-c[Lys-Nle-Glu-His-DPhe-Arg-Trp-Gly-Arg-Pro-Val-Asp]), were synthesized and radiolabeled with (111)In. The internalization and efflux of (111)In-labeled CycMSH peptides were examined in B16/F1 melanoma cells. The melanoma targeting properties, pharmacokinetics, and SPECT/CT imaging of (111)In-labeled CycMSH peptides were determined in B16/F1 melanoma-bearing C57 mice. Both (111)In-DOTA-CycMSH and (111)In-DOTA-GlyGlu-CycMSH exhibited fast internalization and extended retention in B16/F1 cells. The tumor uptake values of (111)In-DOTA-CycMSH and (111)In-DOTA-GlyGlu-CycMSH were 9.53+/-1.41% injected dose/gram (% ID/g) and 10.40+/-1.40% ID/g at 2 h postinjection, respectively. Flank melanoma tumors were clearly visualized with (111)In-DOTA-CycMSH and (111)In-DOTA-GlyGlu-CycMSH by SPECT/CT images at 2 h postinjection. Whole-body clearance of the peptides was fast, with greater than 90% of the radioactivities cleared through urinary system by 2 h postinjection. There was low radioactivity (<0.8% ID/g) accumulated in blood and normal organs except kidneys at all time points investigated. Introduction of a negatively charged linker (-Gly-Glu-) into the peptide sequence decreased the renal uptake by 44% without affecting the tumor uptake at 4 h postinjection. High receptor-mediated melanoma uptakes coupled with fast whole-body clearance in B16/F1 melanoma-bearing C57 mice demonstrated the feasibility of using (111)In-labeled lactam bridge-cyclized alpha-MSH peptide analogues as a novel class of imaging probes for receptor-targeting melanoma imaging.

  1. Trajectory Calculations for Bergman Cyclization Predict H/D Kinetic Isotope Effects Due to Nonstatistical Dynamics in the Product.

    Science.gov (United States)

    Doubleday, Charles; Boguslav, Mayla; Howell, Caronae; Korotkin, Scott D; Shaked, David

    2016-06-22

    An unusual H/D kinetic isotope effect (KIE) is described, in which isotopic selectivity arises primarily from nonstatistical dynamics in the product. In DFT-based quasiclassical trajectories of Bergman cyclization of (Z)-3-hexen-1,5-diyne (1) at 470 K, the new CC bond retains its energy, and 28% of nascent p-benzyne recrosses back to the enediyne on a vibrational time scale. The competing process of intramolecular vibrational redistribution (IVR) in p-benzyne is too slow to prevent this. Deuteration increases the rate of IVR, which decreases the fraction of recrossing and increases the yield of statistical (trapable) p-benzyne, 2. Trapable yields for three isotopomers of 2 range from 72% to 86%. The resulting KIEs for Bergman cyclization differ substantially from KIEs predicted by transition state theory, which suggests that IVR in this reaction can be studied by conventional KIEs. Leakage of vibrational zero point energy (ZPE) into the reaction coordinate was probed by trajectories in which initial ZPE in the CH/CD stretching modes was reduced by 25%. This did not change the predicted KIEs.

  2. Drug Delivery by an Enzyme-Mediated Cyclization of a Lipid Prodrug with Unique Bilayer-Formation Properties

    DEFF Research Database (Denmark)

    Linderoth, Lars; Peters, Günther H.j.; Madsen, Robert

    2009-01-01

    Special delivery: Liposomal drug-delivery systems in which prodrugs are activated specifically by disease-associated enzymes have great potential for the treatment of severe diseases, such as cancer. A new type of phospholipid-based prodrug has the ability to form stable small unilamellar vesicle...... (see picture). Activation of the prodrug vesicles by the enzyme sPLA2 initiates a cyclization reaction, which leads to the release of the drug....

  3. Raman spectroscopic approach to monitor the in vitro cyclization of creatine → creatinine

    Science.gov (United States)

    Gangopadhyay, Debraj; Sharma, Poornima; Singh, Sachin Kumar; Singh, Pushkar; Tarcea, Nicolae; Deckert, Volker; Popp, Jürgen; Singh, Ranjan K.

    2015-01-01

    The creatine → creatinine cyclization, an important metabolic phenomenon has been initiated in vitro at acidic pH and studied through Raman spectroscopic and DFT approach. The equilibrium composition of neutral, zwitterionic and protonated microspecies of creatine has been monitored with time as the reaction proceeds. Time series Raman spectra show clear signature of creatinine formation at pH 3 after ∼240 min at room temperature and reaction is faster at higher temperature. The spectra at pH 1 and pH 5 do not show such signature up to 270 min implying faster reaction rate at pH 3.

  4. Efficient Nazarov cyclization/Wagner-Meerwein rearrangement terminated by a Cu(II)-promoted oxidation: synthesis of 4-alkylidene cyclopentenones.

    Science.gov (United States)

    Lebœuf, David; Theiste, Eric; Gandon, Vincent; Daifuku, Stephanie L; Neidig, Michael L; Frontier, Alison J

    2013-04-08

    The discovery and elucidation of a new Nazarov cyclization/Wagner-Meerwein rearrangement/oxidation sequence is described that constitutes an efficient strategy for the synthesis of 4-alkylidene cyclopentenones. DFT computations and EPR experiments were conducted to gain further mechanistic insight into the reaction pathways. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Solvent- and ligand-induced switch of selectivity in gold(I-catalyzed tandem reactions of 3-propargylindoles

    Directory of Open Access Journals (Sweden)

    Roberto Sanz

    2011-06-01

    Full Text Available The selectivity of our previously described gold-catalyzed tandem reaction, 1,2-indole migration followed by aura-iso-Nazarov cyclization, of 3-propargylindoles bearing (heteroaromatic substituents at both the propargylic and terminal positions, was reversed by the proper choice of the catalyst and the reaction conditions. Thus, 3-(inden-2-ylindoles, derived from an aura-Nazarov cyclization (instead of an aura-iso-Nazarov cyclization, were obtained in moderate to good yields from a variety of 3-propargylindoles.

  6. p-TSA/Base-Promoted Propargylation/Cyclization of β-Ketothioamides for the Regioselective Synthesis of Highly Substituted (Hydro)thiophenes.

    Science.gov (United States)

    Nandi, Ganesh Chandra; Singh, Maya Shankar

    2016-07-15

    Metal-free, p-toluenesulfonic acid (p-TSA)-mediated, straightforward propargylation of β-ketothioamides with aryl propargyl alcohol has been achieved at room temperature. In addition, the reaction also provided thiazole rings as byproducts. Furthermore, the propargylated thioamides undergo intramolecular 1,5-cyclization to afford fully substituted (hydro)thiophenes in the presence of base. Notably, the approach is pot, atom, and step economical (PASE).

  7. Discovery of cyclotides in the fabaceae plant family provides new insights into the cyclization, evolution, and distribution of circular proteins.

    Science.gov (United States)

    Poth, Aaron G; Colgrave, Michelle L; Philip, Reynold; Kerenga, Bomai; Daly, Norelle L; Anderson, Marilyn A; Craik, David J

    2011-04-15

    Cyclotides are plant proteins whose defining structural features are a head-to-tail cyclized backbone and three interlocking disulfide bonds, which in combination are known as a cyclic cystine knot. This unique structural motif confers cyclotides with exceptional resistance to proteolysis. Their endogenous function is thought to be as plant defense agents, associated with their insecticidal and larval growth-inhibitory properties. However, in addition, an array of pharmaceutically relevant biological activities has been ascribed to cyclotides, including anti-HIV, anthelmintic, uterotonic, and antimicrobial effects. So far, >150 cyclotides have been elucidated from members of the Rubiaceae, Violaceae, and Cucurbitaceae plant families, but their wider distribution among other plant families remains unclear. Clitoria ternatea (Butterfly pea) is a member of plant family Fabaceae and through its usage in traditional medicine to aid childbirth bears similarity to Oldenlandia affinis, from which many cyclotides have been isolated. Using a combination of nanospray and matrix-assisted laser desorption ionization-time-of-flight (MALDI-TOF) analyses, we examined seed extracts of C. ternatea and discovered cyclotides in the Fabaceae, the third-largest family of flowering plants. We characterized 12 novel cyclotides, thus expanding knowledge of cyclotide distribution and evolution within the plant kingdom. The discovery of cyclotides containing novel sequence motifs near the in planta cyclization site has provided new insights into cyclotide biosynthesis. In particular, MS analyses of the novel cyclotides from C. ternatea suggest that Asn to Asp variants at the cyclization site are more common than previously recognized. Moreover, this study provides impetus for the examination of other economically and agriculturally significant species within Fabaceae, now the largest plant family from which cyclotides have been described.

  8. Petasis/Diels-Alder/Cyclization Cascade Reactions for the Generation of Scaffolds with Multiple Stereogenic Centers and Orthogonal Handles for Library Production

    DEFF Research Database (Denmark)

    Flagstad, Thomas; Azevedo, Carlos M. G.; Min, Geanna

    2018-01-01

    A new effective strategy for the synthesis of sp3‐rich small molecules for library production is presented. The key steps to generate complexity highlight Petasis 3‐component reaction followed by an intramolecular Diels‐Alder and cyclization to generate a densely enriched tricyclic or tetracyclic...

  9. Higher outcomes of vasectomy reversal in men with the same female partner as before vasectomy.

    Science.gov (United States)

    Ostrowski, Kevin A; Polackwich, A Scott; Kent, Joe; Conlin, Michael J; Hedges, Jason C; Fuchs, Eugene F

    2015-01-01

    We reviewed fertility outcomes of vasectomy reversal at a high surgical volume center in men with the same female partner as before vasectomy. We retrospectively studied a prospective database. All vasectomy reversals were performed by a single surgeon (EFF). Patients who underwent microsurgical vasectomy reversal and had the same female partner as before vasectomy were identified from 1978 to 2011. Pregnancy and live birth rates, procedure type (bilateral vasovasostomy, bilateral vasoepididymostomy, unilateral vasovasostomy or unilateral vasoepididymostomy), patency rate, time from reversal and spouse age were evaluated. We reviewed the records of 3,135 consecutive microsurgical vasectomy reversals. Of these patients 524 (17%) who underwent vasectomy reversal had the same female partner as before vasectomy. Complete information was available on 258 patients (49%), who had a 94% vas patency rate. The clinical pregnancy rate was 83% by natural means compared to 60% in our general vasectomy reversal population (p reversal with the same female partner the OR was 2 (p reversal was 38.9 and 33.2 years, respectively. Outcomes of clinical pregnancy and live birth rates are higher in men who undergo microsurgical vasectomy reversal with the same female partner. These outcomes may be related to a shorter interval from vasectomy, previous fertility and couple motivation. Copyright © 2015 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

  10. Total Synthesis of 15-F2t-Isoprostane by Using a New Oxidative Cyclization of Distonic Radical Anions as the Key Step

    Czech Academy of Sciences Publication Activity Database

    Jahn, Ullrich; Dinca, E.

    2009-01-01

    Roč. 15, č. 1 (2009), s. 58-62 ISSN 0947-6539 Grant - others:DFG(DE) Ja896/3-1 Institutional research plan: CEZ:AV0Z40550506 Keywords : cyclization * electron transfer * prostanoids * radical ions Subject RIV: CC - Organic Chemistry Impact factor: 5.382, year: 2009

  11. A highly selective turn-on fluorescent probe for hypochlorous acid based on hypochlorous acid-induced oxidative intramolecular cyclization of boron dipyrromethene-hydrazone

    International Nuclear Information System (INIS)

    Chen, Wei-Chieh; Venkatesan, Parthiban; Wu, Shu-Pao

    2015-01-01

    Highlights: • A BODIPY-based fluorescent probe for sensing HOCl was developed. • The probe utilizes the HOCl-promoted cyclization in response to the amount of HOCl. • The probe might have application in the investigation of HOCl in biological systems. - Abstract: A BODIPY-based fluorescent probe, HBP, was developed for the detection of hypochlorous acid based on the specific hypochlorous acid-promoted oxidative intramolecular cyclization of heterocyclic hydrazone in response to the amount of HOCl. The reaction is accompanied by a 41-fold increase in the fluorescent quantum yield (from 0.004 to 0.164). The fluorescence intensity of the reaction between HOCl and HBP is linear in the HOCl concentration range of 1–8 μM with a detection limit of 2.4 nM (S/N = 3). Confocal fluorescence microscopy imaging using RAW264.7 cells showed that the new probe HBP could be used as an effective fluorescent probe for detecting HOCl in living cells

  12. A highly selective turn-on fluorescent probe for hypochlorous acid based on hypochlorous acid-induced oxidative intramolecular cyclization of boron dipyrromethene-hydrazone

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Wei-Chieh; Venkatesan, Parthiban; Wu, Shu-Pao, E-mail: spwu@mail.nctu.edu.tw

    2015-07-02

    Highlights: • A BODIPY-based fluorescent probe for sensing HOCl was developed. • The probe utilizes the HOCl-promoted cyclization in response to the amount of HOCl. • The probe might have application in the investigation of HOCl in biological systems. - Abstract: A BODIPY-based fluorescent probe, HBP, was developed for the detection of hypochlorous acid based on the specific hypochlorous acid-promoted oxidative intramolecular cyclization of heterocyclic hydrazone in response to the amount of HOCl. The reaction is accompanied by a 41-fold increase in the fluorescent quantum yield (from 0.004 to 0.164). The fluorescence intensity of the reaction between HOCl and HBP is linear in the HOCl concentration range of 1–8 μM with a detection limit of 2.4 nM (S/N = 3). Confocal fluorescence microscopy imaging using RAW264.7 cells showed that the new probe HBP could be used as an effective fluorescent probe for detecting HOCl in living cells.

  13. Redox regulation of protein tyrosine phosphatase 1B (PTP1B): Importance of steric and electronic effects on the unusual cyclization of the sulfenic acid intermediate to a sulfenyl amide

    Science.gov (United States)

    Sarma, Bani Kanta

    2013-09-01

    The redox regulation of protein tyrosine phosphatase 1B (PTP1B) via the unusual transformation of its sulfenic acid (PTP1B-SOH) to a cyclic sulfenyl amide intermediate is studied by using small molecule chemical models. These studies suggest that the sulfenic acids derived from the H2O2-mediated reactions o-amido thiophenols do not efficiently cyclize to sulfenyl amides and the sulfenic acids produced in situ can be trapped by using methyl iodide. Theoretical calculations suggest that the most stable conformer of such sulfenic acids are stabilized by nO → σ*S-OH orbital interactions, which force the -OH group to adopt a position trans to the S⋯O interaction, leading to an almost linear arrangement of the O⋯S-O moiety and this may be the reason for the slow cyclization of such sulfenic acids to their corresponding sulfenyl amides. On the other hand, additional substituents at the 6-position of o-amido phenylsulfenic acids that can induce steric environment and alter the electronic properties around the sulfenic acid moiety by S⋯N or S⋯O nonbonded interactions destabilize the sulfenic acids by inducing strain in the molecule. This may lead to efficient the cyclization of such sulfenic acids. This model study suggests that the amino acid residues in the close proximity of the sulfenic acid moiety in PTP1B may play an important role in the cyclization of PTP1B-SOH to produce the corresponding sulfenyl amide.

  14. One-Pot Synthesis of Cyclopropane-Fused Cyclic Amidines: An Oxidative Carbanion Cyclization.

    Science.gov (United States)

    Veeranna, Kirana Devarahosahalli; Das, Kanak Kanti; Baskaran, Sundarababu

    2017-12-18

    A novel and efficient one-pot method has been developed for the synthesis of cyclopropane-fused bicyclic amidines on the basis of a CuBr 2 -mediated oxidative cyclization of carbanions. The usefulness of this unique multicomponent strategy has been demonstrated by the use of a wide variety of substrates to furnish novel cyclopropane-containing amidines with a quaternary center in very good yields. This ketenimine-based approach provides straightforward access to biologically active and pharmaceutically important 3-azabicyclo[n.1.0]alkane frameworks under mild conditions. The synthetic power of this methodology is exemplified in the concise synthesis of the pharmaceutically important antidepressant drug candidate GSK1360707 and key intermediates for the synthesis of amitifadine, bicifadine, and narlaprevir. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. A Divergent Mechanistic Course of Pd(0)-Catalyzed Aza-Claisen Rearrangement and Aza-Rautenstrauch-Type Cyclization of N-Allyl-Ynamides

    Science.gov (United States)

    DeKorver, Kyle A.; Hsung, Richard P.; Lohse, Andrew G.; Zhang, Yu

    2010-01-01

    A fascinating mechanistic study of ynamido-palladium-π-allyl complexes is described that features isolation of a unique silyl-ketenimine via aza-Claisen rearrangement, which can be accompanied by an unusual thermal N-to-C 1,3-Ts shift in the formation of tertiary nitriles, and a novel cyclopentenimine formation via a palladium catalyzed aza-Rautenstrauch-type cyclization pathway. PMID:20337418

  16. Synthesis of Substituted 1,4-Dioxenes through O-H Insertion and Cyclization Using Keto-Diazo Compounds.

    Science.gov (United States)

    Davis, Owen A; Croft, Rosemary A; Bull, James A

    2016-11-18

    1,4-Dioxenes present interesting potential as synthetic intermediates and as unusual motifs for incorporation into biologically active compounds. Here, an efficient synthesis of functionalized 1,4-dioxenes is achieved in two steps. Using keto-diazo compounds, a ruthenium catalyzed O-H insertion with β-halohydrins followed by treatment with base results in cyclization with excellent selectivity, through O-alkylation of the keto-enolate. A variety of halohydrins and anion-stabilizing groups in the diazo-component are tolerated, affording novel functionalized dioxenes. Enantioenriched β-bromohydrins provide enantioenriched 1,4-dioxenes.

  17. Convenient synthesis of benzothiazoles and benzimidazoles through Brønsted acid catalyzed cyclization of 2-amino thiophenols/anilines with β-diketones.

    Science.gov (United States)

    Mayo, Muhammad Shareef; Yu, Xiaoqiang; Zhou, Xiaoyu; Feng, Xiujuan; Yamamoto, Yoshinori; Bao, Ming

    2014-02-07

    Brønsted acid catalyzed cyclization reactions of 2-amino thiophenols/anilines with β-diketones under oxidant-, metal-, and radiation-free conditions are described. Various 2-substituted benzothiazoles/benzimidazoles are obtained in satisfactory to excellent yields. Different groups such as methyl, chloro, nitro, and methoxy linked on benzene rings were tolerated under the optimized reaction conditions.

  18. 1,4-Hydroiodination of dienyl alcohols with TMSI to form homoallylic alcohols containing a multisubstituted Z-alkene and application to Prins cyclization.

    Science.gov (United States)

    Xu, Yongjin; Yin, Zhiping; Lin, Xinglong; Gan, Zubao; He, Yanyang; Gao, Lu; Song, Zhenlei

    2015-04-17

    A regioselective 1,4-hydroiodination of dienyl alcohols has been developed using trimethylsilyl iodide as Lewis acid and iodide source. A range of homoallylic alcohols containing a multisubstituted Z-alkene was synthesized with good to excellent configurational control. The approach was applied in sequential hydroiodination/Prins cyclization to afford multisubstituted tetrahydropyrans diastereoselectively.

  19. Reversal of laryngotracheal separation in paediatric patients.

    LENUS (Irish Health Repository)

    Young, Orla

    2012-02-01

    OBJECTIVE: Laryngotracheal separation (LTS) is an effective and reliable definitive treatment for intractable aspiration. A major advantage of this treatment for intractable aspiration is its\\' potential reversibility. Should the underlying disorder improve, a reversal of the procedure may be attempted. This has been successfully achieved in the adult population. To our knowledge, no previous cases have been reported of successful reversal of LTS in children. METHODS: A retrospective review from 2003 to 2010 identified four cases of intractable aspiration treated with LTS in our department. Two of these patients displayed objective evidence of sufficient recovery of their underlying aspiration to consider reversal. Patient selection for reversal was dependent upon successful oral intake for 9 months along with videofluoroscopic evidence of normal or minimally impaired swallow. RESULTS: Two children who were successfully treated for intractable aspiration with LTS demonstrated objective evidence of recovery sufficient to attempt reversal. Both children underwent successful surgical reversal of LTS using a cricotracheal resection with end-to-end anastamosis, similar to that used in treatment of subglottic stenosis. Both children can now tolerate oral diet and their speech and language development is in line with their overall developmental level. CONCLUSIONS: Laryngotracheal separation is an effective and reliable definitive treatment for intractable aspiration facilitating protection of the airway and allowing safe swallowing with unimpeded respiration, but with the major drawback of loss of phonation. To our knowledge, we document the first two cases of successful LTS reversal in children.

  20. Deconstructing selectivity in the gold-promoted cyclization of alkynyl benzothioamides to six-membered mesoionic carbene or acyclic carbene complexes

    KAUST Repository

    Vummaleti, Sai V. C.; Falivene, Laura; Poater, Albert; Cavallo, Luigi

    2014-01-01

    We demonstrate that the experimentally observed switch in selectivity from 5-exo-dig to 6-endo-dig cyclization of an alkynyl substrate, promoted by Au I and AuIII complexes, is connected to a switch from thermodynamic to kinetic reaction control. The AuIII center pushes alkyne coordination toward a single Au-C(alkyne) σ-bond, conferring carbocationic character (and reactivity) to the distal alkyne C atom. © 2014 American Chemical Society.

  1. Deconstructing selectivity in the gold-promoted cyclization of alkynyl benzothioamides to six-membered mesoionic carbene or acyclic carbene complexes

    KAUST Repository

    Vummaleti, Sai V. C.

    2014-05-02

    We demonstrate that the experimentally observed switch in selectivity from 5-exo-dig to 6-endo-dig cyclization of an alkynyl substrate, promoted by Au I and AuIII complexes, is connected to a switch from thermodynamic to kinetic reaction control. The AuIII center pushes alkyne coordination toward a single Au-C(alkyne) σ-bond, conferring carbocationic character (and reactivity) to the distal alkyne C atom. © 2014 American Chemical Society.

  2. Microwave-assisted cyclizations promoted by polyphosphoric acid esters: a general method for 1-aryl-2-iminoazacycloalkanes

    Directory of Open Access Journals (Sweden)

    Jimena E. Díaz

    2016-09-01

    Full Text Available The first general procedure for the synthesis of 5 to 7-membered 1-aryl-2-iminoazacycloalkanes is presented, by microwave-assisted ring closure of ω-arylaminonitriles promoted by polyphosphoric acid (PPA esters. 1-Aryl-2-iminopyrrolidines were easily prepared from the acyclic precursors employing a chloroformic solution of ethyl polyphosphate (PPE. The use of trimethylsilyl polyphosphate (PPSE in solvent-free conditions allowed for the synthesis of 1-aryl-2-iminopiperidines and hitherto unreported 1-aryl-2-iminoazepanes. The cyclization reaction involves good to high yields and short reaction times, and represents a novel application of PPA esters in heterocyclic synthesis.

  3. The quantum-chemical investigation of N-cyclization reaction mechanism for epichlorohydrin aminolysis products

    Directory of Open Access Journals (Sweden)

    Andrey V. Tokar

    2014-12-01

    Full Text Available The mechanism of intramolecular cyclization for products of epichlorohydrin aminolysis by secondary amines has been investigated at ab initio level of theory. By comparative analysis of energetic characteristics, which obtained in vacuo as well as in acetonitrile solution with the trace quantities of water as an «active» solvation partner of reaction, it has been shown a decisive role of solvent, which occurs mainly at the expense of the polarizable effects for nonspecific solvation. Indeed, the addition to the substrate of one water molecule have decreased corresponding EACT values only 24.1 kJ/mol, while the appearance of acetonitrile surroundings have the same influence ~42.0 kJ/mol. The results of calculations are in good agreement with that data, which have been obtained for such type modeling previously.

  4. Concise stereocontrolled formal synthesis of (+/-)-quinine and total synthesis of (+/-)-7- hydroxyquinine via merged Morita-Baylis-Hillman-Tsuji-Trost cyclization.

    Science.gov (United States)

    Webber, Peter; Krische, Michael J

    2008-12-05

    Concise stereoselective syntheses of (+/-)-quinine and (+/-)-7-hydroxyquinine are achieved using a catalytic enone cycloallylation that combines the nucleophilic features of the Morita-Baylis-Hillman reaction and the electrophilic features of the Tsuji-Trost reaction. Cyclization of enone-allyl carbonate 11 delivers the product of cycloallylation 13 in 68% yield. Diastereoselective conjugate reduction of the enone 13 (>20:1 dr) followed by exchange of the N-protecting group provides the saturated N-Boc-protected methyl ketone 19, which upon aldol dehydration provides quinoline containing enone 15, possessing all carbon atoms of quinine. Exposure of ketone 15 to L-selectride enables diastereoselective carbonyl reduction (>20:1 dr) to furnish the allylic alcohol 16. Stereoselective hydroxyl-directed epoxidation using an oxovanadium catalyst modified by N-hydroxy-N-Me-pivalamide delivers epoxide 17 (17:1 dr). Cyclization of the resulting amine-epoxide 17 provides (+/-)-7-hydroxyquinine in 13 steps and 11% overall yield from aminoacetaldehyde diethyl acetal. Notably, highly stereoselective formation of five contiguous stereocenters is achieved through a series of 1,2-asymmetric induction events. Deoxygenation of the N-Cbz-protected allylic acetate 22 provides olefin 23, which previously has been converted to quinine. Thus, (+/-)-quinine is accessible in 16 steps and 4% overall yield from commercial aminoacetaldehyde diethyl acetal.

  5. Stereoselective synthesis of 1,3-disubstituted isoindolines via Rh(III)-catalyzed tandem oxidative olefination-cyclization of 4-aryl cyclic sulfamidates.

    Science.gov (United States)

    Son, Se-Mi; Seo, Yeon Ji; Lee, Hyeon-Kyu

    2016-03-21

    Rh(III)-catalyzed tandem ortho C-H olefination of cyclic 4-aryl sulfamidates (1) and subsequent intramolecular cyclization are described. This reaction serves as a method for the direct and stereoselective synthesis of 1,3-disubstituted isoindolines (3) starting with enantiomerically enriched 4-aryl cyclic sulfamidates. In this process, the configurational integrity of the stereogenic center in the starting cyclic sulfamidate is completely retained. In addition, the process generates trans-1,3-disubstituted isoindolines exclusively.

  6. Palladium-Catalyzed Atom-Transfer Radical Cyclization at Remote Unactivated C(sp3 )-H Sites: Hydrogen-Atom Transfer of Hybrid Vinyl Palladium Radical Intermediates.

    Science.gov (United States)

    Ratushnyy, Maxim; Parasram, Marvin; Wang, Yang; Gevorgyan, Vladimir

    2018-03-01

    A novel mild, visible-light-induced palladium-catalyzed hydrogen atom translocation/atom-transfer radical cyclization (HAT/ATRC) cascade has been developed. This protocol involves a 1,5-HAT process of previously unknown hybrid vinyl palladium radical intermediates, thus leading to iodomethyl carbo- and heterocyclic structures. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Mode selectivity in the intramolecular cyclization of ketenimines bearing N-acylimino units: a computational and experimental study.

    Science.gov (United States)

    Alajarín, Mateo; Sánchez-Andrada, Pilar; Vidal, Angel; Tovar, Fulgencio

    2005-02-18

    [reaction: see text] The mode selectivity in the intramolecular cyclization of a particular class of ketenimines bearing N-acylimino units has been studied by ab initio and DFT calculations. In the model compounds the carbonyl carbon atom and the keteniminic nitrogen atom are linked either by a vinylic or an o-phenylene tether. Two cyclization modes have been analyzed: the [2+2] cycloaddition furnishing compounds with an azeto[2,1-b]pyrimidinone moiety and a 6pi-electrocyclic ring closure leading to compounds enclosing a 1,3-oxazine ring. The [2+2] cycloaddition reaction takes place via a two-step process with formation of a zwitterionic intermediate, which has been characterized as a cross-conjugated mesomeric betaine. The 6pi-electrocyclic ring closure occurs via a transition state whose pseudopericyclic character has been established on the basis of its magnetic properties, geometry, and NBO analysis. The 6pi-electrocyclic ring closure is energetically favored over the [2+2] cycloaddition, although the [2+2] cycloadducts are the thermodynamically controlled products. A quantitative kinetic analysis predicts that 1,3-oxazines would be the kinetically controlled products, but they should transform rapidly and totally into the [2+2] cycloadducts at room temperature. In the experimental study, a number of N-acylimino-ketenimines, in which both reactive functions are supported on an o-phenylene scaffold, have been successfully synthesized in three steps starting from 2-azidobenzoyl chloride. These compounds rapidly convert into azeto[2,1-b]quinazolin-8-ones in moderate to good yields as a result of a formal [2+2] cycloaddition.

  8. Ready synthesis of free N-H 2-arylindoles via the copper-catalyzed amination of 2-bromo-arylacetylenes with aqueous ammonia and sequential intramolecular cyclization.

    Science.gov (United States)

    Wang, Huifeng; Li, Yaming; Jiang, Linlin; Zhang, Rong; Jin, Kun; Zhao, Defeng; Duan, Chunying

    2011-07-07

    A wide range of free N-H 2-arylindoles were synthesised via the copper(II)-catalyzed amination of 2-bromo-arylacetylenes with aqueous ammonia and sequential intramolecular cyclization. The convenience and atom economy of aqueous ammonia, and the low cost of the copper catalytic system make this protocol readily superior in practical application.

  9. Cyclization Reaction of Acyl Thiourea Chitosan: Enhanced Antifungal Properties via Structural Optimization.

    Science.gov (United States)

    Qin, Yukun; Liu, Weixiang; Xing, Ronge; Liu, Song; Li, Kecheng; Li, Pengcheng

    2018-03-06

    In this study, 3-methyl-1,2,4-triazolyl chitosan (MTACS) and 3-chloromethyl-1,2,4-triazolyl chitosan (CMTACS) were prepared via cyclization of acyl thiourea chitosan (TUCS). Their structures were confirmed by FT-IR, ¹H-NMR, elemental analysis, DSC, XRD, and SEM. The conformations were predicted using the Gaussian 09 program. Additionally, the antifungal properties of MTACS and CMTACS against Stemphylium solani weber ( S. solani ), Alternaria porri ( A. porri ), and Gloeosporium theae-sinensis ( G. theae-sinensis ) were assayed in vitro and ranged from 250 μg/mL to 1000 μg/mL. The results showed that MTACS and CMTACS exhibited enhanced inhibitory effect on the selected fungi compared to the original chitosan and TUCS. In particular, they displayed better antifungal activities against A. porri and G. theae-sinensis than that of the positive control, Triadimefon. The findings described here may lead to them being used as antifungal agents for crop protection.

  10. Cyclization Reaction of Acyl Thiourea Chitosan: Enhanced Antifungal Properties via Structural Optimization

    Directory of Open Access Journals (Sweden)

    Yukun Qin

    2018-03-01

    Full Text Available In this study, 3-methyl-1,2,4-triazolyl chitosan (MTACS and 3-chloromethyl-1,2,4-triazolyl chitosan (CMTACS were prepared via cyclization of acyl thiourea chitosan (TUCS. Their structures were confirmed by FT-IR, 1H-NMR, elemental analysis, DSC, XRD, and SEM. The conformations were predicted using the Gaussian 09 program. Additionally, the antifungal properties of MTACS and CMTACS against Stemphylium solani weber (S. solani, Alternaria porri (A. porri, and Gloeosporium theae-sinensis (G. theae-sinensis were assayed in vitro and ranged from 250 μg/mL to 1000 μg/mL. The results showed that MTACS and CMTACS exhibited enhanced inhibitory effect on the selected fungi compared to the original chitosan and TUCS. In particular, they displayed better antifungal activities against A. porri and G. theae-sinensis than that of the positive control, Triadimefon. The findings described here may lead to them being used as antifungal agents for crop protection.

  11. Effect of DOTA position on melanoma targeting and pharmacokinetic properties of 111In-labeled lactam bridge-cyclized alpha-melanocyte stimulating hormone peptide.

    Science.gov (United States)

    Guo, Haixun; Yang, Jianquan; Gallazzi, Fabio; Prossnitz, Eric R; Sklar, Larry A; Miao, Yubin

    2009-11-01

    The purpose of this study was to examine the effect of DOTA (1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) position on melanoma targeting and pharmacokinetics of radiolabeled lactam bridge-cyclized alpha-melanocyte stimulating hormone (alpha-MSH) peptide. A novel lactam bridge-cyclized alpha-MSH peptide, Ac-GluGlu-CycMSH[DOTA] {Ac-Glu-Glu-c[Lys-Nle-Glu-His-DPhe-Arg-Trp-Gly-Arg-Pro-Val-Lys(DOTA)]}, was synthesized using standard 9-fluorenylmethyloxycarbonyl (Fmoc) chemistry. DOTA was directly attached to the alpha-amino group of Lys in the cyclic ring, while the N-terminus of the peptide was acetylated to generate Ac-GluGlu-CycMSH[DOTA]. The MC1 receptor binding affinity of Ac-GluGlu-CycMSH[DOTA] was determined in B16/F1 melanoma cells. Melanoma targeting and pharmacokinetic properties of Ac-GluGlu-CycMSH[DOTA]-111In were determined in B16/F1 melanoma-bearing C57 mice and compared to that of 111In-DOTA-Gly-Glu-c[Lys-Nle-Glu-His-DPhe-Arg-Trp-Gly-Arg-Pro-Val-Asp] (111In-DOTA-GlyGlu-CycMSH; DOTA was coupled to the N-terminus of the peptide). Ac-GluGlu-CycMSH[DOTA] displayed 0.6 nM MC1 receptor binding affinity in B16/F1 cells. Ac-GluGlu-CycMSH[DOTA]-111In was readily prepared with greater than 95% radiolabeling yield. Ac-GluGlu-CycMSH[DOTA]-111In exhibited high tumor uptake (11.42 +/- 2.20% ID/g 2 h postinjection) and prolonged tumor retention (9.42 +/- 2.41% ID/g 4 h postinjection) in B16/F1 melanoma-bearing C57 mice. The uptake values for nontarget organs were generally low (<1.3% ID/g) except for the kidneys 2, 4, and 24 h postinjection. DOTA position exhibited profound effect on melanoma targeting and pharmacokinetic properties of Ac-GluGlu-CycMSH[DOTA]-111In, providing a new insight into the design of lactam bridge-cyclized peptide for melanoma imaging and therapy.

  12. Synthesis of Some New 2-(3-Aryl-1-phenyl-4-pyrazolyl-benzoxazoles Using Hypervalent Iodine Mediated Oxidative Cyclization of Schiff’s Bases

    Directory of Open Access Journals (Sweden)

    Ajay Kumar

    2006-01-01

    Full Text Available Ten new 2-(3-aryl-1-phenyl-4-pyrazolylbenzoxazoles have been synthesized by oxidative intramolecular cyclization of the corresponding Schiff’s bases using iodobenzene diacetate in methanol as an oxidant.

  13. Ternary iron(II) complex with an emissive imidazopyridine arm from Schiff base cyclizations and its oxidative DNA cleavage activity

    OpenAIRE

    Mukherjee, Arindam; Dhar, Shanta; Nethaji, Munirathinam; Chakravarty, Akhil R

    2005-01-01

    The ternary iron(II) complex [Fe(L')(L")] $(PF_6)_3(1)$ as a synthetic model for the bleomycins, where L' and L" are formed from metal-mediated cyclizations of N,N -(2-hydroxypropane-1,3-diyl)bis(pyridine-2-aldimine)(L), is synthesized and structurally characterized by X-ray crystallography. In the six-coordinate iron(II) complex, ligands L' and L" show tetradentate and bidentate chelating modes of bonding. Ligand L' is formed from an intramolecular attack of the alcoholic OH group of L to o...

  14. Roux en Y gastric bypass hypoglycemia resolves with gastric feeding or reversal: Confirming a non-pancreatic etiology

    Directory of Open Access Journals (Sweden)

    Dawn Belt Davis

    2018-03-01

    Full Text Available Objective: Postprandial hypoglycemia is an infrequent but disabling complication of Roux-en-Y gastric bypass (RYGB surgery. Controversy still exists as to whether the postprandial hyperinsulinemia observed is due to inherent changes in pancreatic β-cell mass or function or to reversible alterations caused by RYGB anatomy. We aimed to determine if gastric feeding or reversal of RYGB would normalize postprandial glucose and hormone excursions in patients with symptomatic hypoglycemia. Methods: We completed a prospective study of six patients with severe symptomatic RYGB hypoglycemia who underwent RYGB reversal. An additional subject without hypoglycemia who underwent RYGB reversal was also studied prospectively. Mixed meal tolerance testing (MTT was done orally (RYGB anatomy, via gastrostomy tube in the excluded stomach in the setting of RYGB, and several months after RYGB reversal. Results: All subjects reported symptomatic improvement of hypoglycemia after reversal of RYGB. Weight gain after reversal was moderate and variable. Postprandial glucose, insulin, and GLP-1 excursions were significantly diminished with gastric feeding and after reversal. Insulin secretion changed proportional to glucose levels and insulin clearance increased after reversal. Glucagon/insulin ratios were similar throughout study. We further compared the impact of modified sleeve gastrectomy reversal surgery to those with restoration of complete stomach and found no significant differences in weight regain or in postprandial glucose or hormone levels. Conclusions: Reversal of RYGB is an effective treatment option for severe postprandial hypoglycemia. The pathophysiology of this disorder is primarily due to RYGB anatomy resulting in altered glucose, gut, and pancreatic hormone levels and decreased insulin clearance, rather than inherent β-cell hyperplasia or hyperfunction. Keywords: Hypoglycemia, Insulin, Glucagon-like peptide 1, Roux en Y gastric bypass, Gastric bypass

  15. Cranial MR finding of reversible eclampsia

    Energy Technology Data Exchange (ETDEWEB)

    Sohn, Seok Ho; Hwang, Mi Young; Kim, Kyu Hwa; Kim, Seon Goo; Lee, Sung Moon; Kim, Hong; Joo, Yang Goo; Suh, Soo Ji [College of Medicine, Keimyung University, Daegu (Korea, Republic of)

    1994-05-15

    To evaluate clinical usefulness of cranial magnetic resonance imaging(MRI) in diagnosis and for follow-up of reversible eclampsia. Cranial MRI was performed on four consecutive pregnant patients(ante-partum 3 cases, postpartum 1 cases), who had generalized tonic-clonic seizure caused by eclampsia. One of the four patients underwent follow-up MRI. Cranial MRI typically demonstrated bilateral hyperintense lesions on T2-weighted images and iso-to hypointense lesions on T1-weighted images. MRI abnormalities were most commonly located in the distribution of the posterior cerebral artery circulation and were associated with symptoms of visual disturbance. Most cranial lesions of eclampsia demonstrated in MRI were reversible. MRI with its capability to detect even subtle abnormalities in the brain that are not visible on CT, and may be the technique of choice for evaluating the cerebral the pathology of pregnant women with eclampsia.

  16. Copper-catalyzed difunctionalization of activated alkynes by radical oxidation-tandem cyclization/dearomatization to synthesize 3-trifluoromethyl spiro[4.5]trienones.

    Science.gov (United States)

    Hua, Hui-Liang; He, Yu-Tao; Qiu, Yi-Feng; Li, Ying-Xiu; Song, Bo; Gao, Pin; Song, Xian-Rong; Guo, Dong-Hui; Liu, Xue-Yuan; Liang, Yong-Min

    2015-01-19

    A copper-catalyzed difunctionalizing trifluoromethylation of activated alkynes with the cheap reagent sodium trifluoromethanesulfinate (NaSO2CF3 or Langlois' reagent) has been developed incorporating a tandem cyclization/dearomatization process. This strategy affords a straightforward route to synthesis of 3-(trifluoromethyl)-spiro[4.5]trienones, and presents an example of difunctionalization of alkynes for simultaneous formation of two carbon-carbon single bonds and one carbon-oxygen double bond. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. SOCl2 catalyzed cyclization of chalcones: Synthesis and spectral studies of some bio-potent 1H pyrazoles

    Directory of Open Access Journals (Sweden)

    K. Ranganathan

    2014-05-01

    Full Text Available Some aryl-aryl 1H pyrazoles have been synthesised by cyclization of aryl chalcones and hydrazine hydrate in the presence of SOCl2. The yields of the pyrazoles are more than 85%. These pyrazoles are characterized by their physical constants and spectral data. The infrared, NMR spectral group frequencies of these pyrazolines have been correlated with Hammett substituent constants, F and R parameters. From the results of statistical analyses the effects of substituent on the spectral frequencies have been studied. The antimicrobial activities of all synthesised pyrazolines have been studied using Bauer-Kirby method. DOI: http://dx.doi.org/10.4314/bcse.v28i2.11

  18. Mass spectrometric investigation of cyclication of diazo compounds. XI. Cyclization of 1-diazo-4-methoxycarbonyl-2-butanones

    International Nuclear Information System (INIS)

    Lebedev, A.T.; Kazaryan, A.G.; Sharbatyan, P.A.; Sipyagin, A.M.; Kartsev, V.G.; Petrosyan, V.S.

    1988-01-01

    On the basis of the electron-impact mass spectra of a series of 1-diazo-4-methoxycarbonyl-2-butanones, the data from high-solution mass spectrometry, and the spectrum of the deuterated analog it was shown that the [M-N 2 ] +center-dot ions formed at the first stage in the fragmentation of the molecular ions of these compounds are partly stabilized with the formation of pseudomolecular ions of oxolanones. The molecular ions of the diazo ketones themselves can dissociate in various directions. The many-path dissociation makes it possible to suppose that the yield of oxolanones formed during cyclization in solution under the influence of acidic agents is small

  19. Melanoma targeting with [99mTc(N)(PNP3)]-labeled α-melanocyte stimulating hormone peptide analogs: Effects of cyclization on the radiopharmaceutical properties

    International Nuclear Information System (INIS)

    Carta, Davide; Salvarese, Nicola; Morellato, Nicolò; Gao, Feng; Sihver, Wiebke; Pietzsch, Hans Jurgen; Biondi, Barbara; Ruzza, Paolo; Refosco, Fiorenzo; Carpanese, Debora; Rosato, Antonio; Bolzati, Cristina

    2016-01-01

    The purpose of this study was to evaluate the effect of cyclization on the biological profile of a [ 99m Tc(N)(PNP3)]-labeled α-melanocyte stimulating hormone peptide analog. A lactam bridge-cyclized H-Cys-Ahx-βAla 3 -c[Lys 4 -Glu-His-D-Phe-Arg-Trp-Glu 10 ]-Arg 11 -Pro-Val-NH 2 (NAP―NS2) and the corresponding linear H-Cys-Ahx-βAla-Nle-Asp-His-D-Phe-Arg-Trp-Gly-NH 2 (NAP―NS1) peptide were synthetized, characterized by ESI-MS spectroscopy and their melanocortin-1 receptor (MC1R) binding affinity was determined in B16/F10 melanoma cells. The consistent [ 99m Tc(N)(PNP3)]-labeled compounds were readily obtained in high specific activity and their stability and biological properties were assessed. As an example, the chemical identity of [ 99m Tc(N)(NAP–NS1)(PNP3)] + was confirmed by carrier added experiments supported by radio/UV HPLC analysis combined with ESI(+)-MS. Compared with the linear peptide, cyclization negatively affected the biological properties of NAP–NS2 peptide by reducing its binding affinity for MC1R and by decreasing the overall excretion rate of the corresponding [ 99m Tc(N)(PNP3)]-labeled peptide from the body as well as its in vivo stability. [ 99m Tc(N)(NAP–NS1)(PNP3)] + was evaluated for its potential as melanoma imaging probe in murine melanoma model. Data from in vitro and in vivo studies on B16/F10 melanoma model of [ 99m Tc(N)(NAP–NS1)(PNP3)] + clearly evidenced that the radiolabeled linear peptide keeps its biological properties up on the conjugation to the [ 99m Tc(N)(PNP3)]-building block. The progressive increase of the tumor-to-nontarget ratios over the time indicates a quite stable interaction between the radio-complex and the MC1R.

  20. Ruthenium Hydride/Brønsted Acid-Catalyzed Tandem Isomerization/N-Acyliminium Cyclization Sequence for the Synthesis of Tetrahydro-β-carbolines

    DEFF Research Database (Denmark)

    Hansen, Casper Lykke; Clausen, Janie Regitse Waël; Ohm, Ragnhild Gaard

    2013-01-01

    This paper describes an efficient tandem sequence for the synthesis of 1,2,3,4-tetrahydro-β-carbolines (THBCs) relying on a ruthenium hydride/Brønsted acid- catalyzed isomerization of allylic amides to N-acyliminium ion intermediates which are trapped by a tethered indolenucleophile. The methodol...... the Suzuki cross-coupling reaction to the isomerization/N-acyliminium cyclization sequence. Finally, diastereo- and enantioselective versions of the title reaction have been examined using substrate control (with dr >15: 1) and asymmetric catalysis (ee up to 57%), respectively...

  1. Synthesis and characterization of cyclic polystyrene using copper-catalyzed alkyne-azide cycloaddition coupling - evaluation of physical properties and optimization of cyclization conditions

    Science.gov (United States)

    Elupula, Ravinder

    Polymers with a cyclic topology exhibit a range of unique and potentially useful physical properties, including reduced rates of degradation and increased rates of diffusion in bulk relative to linear analogs. However the synthesis of high purity cyclic polymers, and verification of their structural purity remains challenging. The copper-catalyzed azide-alkyne "click" cyclization route toward cyclic polymers has been used widely, due to its synthetic ease and its compatibility with diverse polymer backbones. Yet unoptimized click cyclization conditions have been observed to generate oligomeric byproducts. In order to optimize these cyclization conditions, and to better understand the structure of the higher molecular weight oligomers, these impurities have been isolated by size exclusion chromatography (SEC) and characterized by mass spectrometry (MS). Matrix-Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry (MALDI-ToF) MS is a particularly valuable characterization tool and was used to determine that the high molecular weight impurities are predominantly cyclic oligomers. It should also be noted that the rapid analysis and small analyte requirements of this MS technique make it particularly attractive as a general tool for elucidating polymer architecture. Ability to tailor the physical properties of polymers by changing the architecture alone has garnered a lot of attention over the past few decades. Compared to their linear analogues, these novel polymer architectures behave completely different in nanoscale regime. Cyclic polymers are especially intriguing since we can compare the differences in the physical properties with that of the linear chains. One of the major physical property changes are T g-confinement effect. Using ATRP and "click chemistry" we have produced highly pure cyclic PS (c-PS) with number-average molecular weight (MW) of 3.4 kg/mol and 9.1 kg/mol. Bulk glass transition temperatures for c-PS were weakly depended on MWs

  2. In Situ Cyclization of Native Proteins: Structure-Based Design of a Bicyclic Enzyme.

    Science.gov (United States)

    Pelay-Gimeno, Marta; Bange, Tanja; Hennig, Sven; Grossmann, Tom N

    2018-05-30

    Increased tolerance of enzymes towards thermal and chemical stress is required for many applications and can be achieved by macrocyclization of the enzyme resulting in the stabilizing of its tertiary structure. So far, macrocyclization approaches utilize a very limited structural diversity which complicates the design process. Here, we report an approach that enables cyclization via the installation of modular crosslinks into native proteins composed entirely of proteinogenic amino acids. Our stabilization procedure involves the introduction of three surface exposed cysteines which are reacted with a triselectrophile resulting in the in situ cylization of the protein (INCYPRO). A bicyclic version of Sortase A was designed exhibiting increased tolerance towards thermal as well as chemical denaturation, and proved efficient in protein labeling under denaturing conditions. In addition, we applied INCYPRO to the KIX domain resulting in up to 24 °C increased thermal stability. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Solvent and electronic effects on kinetics of cyclization of thermolabile aryllithium reagents. A comparison between 1-bromo-2-(2-bromoethylbenzene and 4,5-dimethoxy-1-bromo-2-(2-bromoethylbenzene

    Directory of Open Access Journals (Sweden)

    David A. Hunt

    2009-05-01

    Full Text Available A dramatic solvent effect on the stability and kinetics of intramolecular cyclization is described for the aryllithium species generated from 2-bromo-4,5-dimethoxy-(2-bromoethylbenzene. The aryllithium generated by the halogen-metal exchange reaction with n-butyllithium, is stable for > 1h when generated at -95 to -100 oC in diethyl ether/hexane and can be trapped with electrophiles. However, when the reaction is conducted in a THF/hexane mixture, the intermediate undergoes instantaneous intramolecular cyclization to afford 4,5-dimethoxybenzocyclobutene. By comparison, the corresponding 1-lithio-2-(2-bromoethyl-benzene intermediate is stable for >1h in either THF/hexane or diethyl ether/hexane at -95 to -100 oC. These results indicate that substituent effects as well as the nature of aggregation of these intermediates play key roles in determining the reaction pathway of functionalized aryllithium intermediates when quenched with electrophiles.

  4. Synthesis of 2-azaindolizines by using an iodine-mediated oxidative desulfurization promoted cyclization of N-2-pyridylmethyl thioamides and an investigation of their photophysical properties.

    Science.gov (United States)

    Shibahara, Fumitoshi; Kitagawa, Asumi; Yamaguchi, Eiji; Murai, Toshiaki

    2006-11-23

    Iodine-mediated, oxidative desulfurization promoted cyclization of N-2-pyridylmethyl thioamides serves as an efficient and versatile method for the preparation of 2-azaindolizines (imidazo[1,5-a]pyridines) and rare 2-azaindolizine sulfur-bridged dimers. The 2-azaindolizines prepared in this manner are readily converted to a variety of fluorescent compounds by using transition-metal-catalyzed cross-coupling reactions. [reaction: see text].

  5. Reversal Surgery in Regretful Male-to-Female Transsexuals After Sex Reassignment Surgery.

    Science.gov (United States)

    Djordjevic, Miroslav L; Bizic, Marta R; Duisin, Dragana; Bouman, Mark-Bram; Buncamper, Marlon

    2016-06-01

    Sex reassignment surgery (SRS) has proved an effective intervention for patients with gender identity disorder. However, misdiagnosed patients sometimes regret their decision and request reversal surgery. This review is based on our experience with seven patients who regretted their decision to undergo male-to-female SRS. To analyze retrospectively seven patients who underwent reversal surgery after regretting their decision to undergo male-to-female SRS elsewhere. From November 2010 through November 2014, seven men 33 to 53 years old with previous male-to-female SRS underwent reversal phalloplasty. Preoperatively, they were examined by three independent psychiatrists. Surgery included three steps: removal of female genitalia with scrotoplasty and urethral lengthening, total phalloplasty with microvascular transfer of a musculocutaneous latissimus dorsi flap, and neophallus urethroplasty with penile prosthesis implantation. Self-reported esthetic and psychosexual status after reversion surgery and International Index of Erectile Function scores for sexual health after phalloplasty and penile prosthesis implantation. Follow-up was 13 to 61 months (mean = 31 months). Good postoperative results were achieved in all patients. In four patients, all surgical steps were completed; two patients are currently waiting for penile implants; and one patient decided against the penile prosthesis. Complications were related to urethral lengthening: two fistulas and one stricture were observed. All complications were repaired by minor revision. According to patients' self-reports, all patients were pleased with the esthetic appearance of their genitalia and with their significantly improved psychological status. Reversal surgery in regretful male-to-female transsexuals after SRS represents a complex, multistage procedure with satisfactory outcomes. Further insight into the characteristics of persons who regret their decision postoperatively would facilitate better future

  6. Reversible posterior leukoencephalopathy syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eun Ja; Yu, Won Jong; Ahn, Kook Jin; Jung, So Lyung; Lee, Yeon Soo; Kim, Ji Chang; Kang, Si Won [The Catholic Univ. of Korea, Taejon (Korea, Republic of); Song, Chang Joon [Chungnam National Univ. School of Medicine, Cheonju (Korea, Republic of); Song, Soon-Young; Koo, Ja Hong [Kwandong Univ. College of Medicine, Myungji Hospital, Seoul (Korea, Republic of); Kim, Man Deuk [College of Medicine Pochon CHA Univ., Seoul (Korea, Republic of)

    2001-10-01

    To review reversible posterior leukoencephalopathy syndrome. We reviewed 22 patients (M:F=3:19; age, 17-46 years) with the characteristic clinical and imaging features of reversible posterior leukoencephalopathy syndrome. All underwent brain MRI, and in three cases both CT and MRI were performed. In one, MRA was obtained, and in eleven, follow-up MR images were obtained. We evaluated the causes of this syndrome, its clinical manifestations, and MR findings including the locations of lesions, the presence or absence of contrast enhancement, and the changes seen at follow-up MRI. Of the 22 patients, 13 had eclampsia (six during pregnancy and seven during puerperium). Four were receiving immunosuppressive therapy (three, cyclosporine ; one, FK 506). Four suffered renal failure and one had complicated migraine. The clinical manifestations included headache (n=12), visual disturbance (n=13), seizure (n=15), focal neurologic sign (n=3), and altered mental status (n=2). Fifteen patients had hypertension and the others normotension. MRI revealed that lesions were bilateral (n=20) or unilateral (n=2). In all patients the lesion was found in the cortical and subcortical areas of the parieto-occipital lobes ; other locations were the basal ganglia (n=9), posterior temporal lobe (n=8), frontal lobe (n=5), cerebellum (n=5), pons (n=2), and thalamus (n=1). All lesions were of high signal intensity on T2-weighted images, and of iso to low intensity on T1-weighted images. One was combined with acute hematoma in the left basal ganglia. In eight of 11 patients who underwent postcontrast T1-weighted MRI, there was no definite enhancement ; in one, enhancement was mild, and in tow, patchy. CT studies showed low attenuation, and MRA revealed mild vasospasm. The symptoms of all patients improved. Follow-up MRI in nine of 11 patients depicted complete resolution of the lesions ; in two, small infarctions remained but the extent of the lesions had decreased. Reversible posterior

  7. Reversible posterior leukoencephalopathy syndrome

    International Nuclear Information System (INIS)

    Lee, Eun Ja; Yu, Won Jong; Ahn, Kook Jin; Jung, So Lyung; Lee, Yeon Soo; Kim, Ji Chang; Kang, Si Won; Song, Chang Joon; Song, Soon-Young; Koo, Ja Hong; Kim, Man Deuk

    2001-01-01

    To review reversible posterior leukoencephalopathy syndrome. We reviewed 22 patients (M:F=3:19; age, 17-46 years) with the characteristic clinical and imaging features of reversible posterior leukoencephalopathy syndrome. All underwent brain MRI, and in three cases both CT and MRI were performed. In one, MRA was obtained, and in eleven, follow-up MR images were obtained. We evaluated the causes of this syndrome, its clinical manifestations, and MR findings including the locations of lesions, the presence or absence of contrast enhancement, and the changes seen at follow-up MRI. Of the 22 patients, 13 had eclampsia (six during pregnancy and seven during puerperium). Four were receiving immunosuppressive therapy (three, cyclosporine ; one, FK 506). Four suffered renal failure and one had complicated migraine. The clinical manifestations included headache (n=12), visual disturbance (n=13), seizure (n=15), focal neurologic sign (n=3), and altered mental status (n=2). Fifteen patients had hypertension and the others normotension. MRI revealed that lesions were bilateral (n=20) or unilateral (n=2). In all patients the lesion was found in the cortical and subcortical areas of the parieto-occipital lobes ; other locations were the basal ganglia (n=9), posterior temporal lobe (n=8), frontal lobe (n=5), cerebellum (n=5), pons (n=2), and thalamus (n=1). All lesions were of high signal intensity on T2-weighted images, and of iso to low intensity on T1-weighted images. One was combined with acute hematoma in the left basal ganglia. In eight of 11 patients who underwent postcontrast T1-weighted MRI, there was no definite enhancement ; in one, enhancement was mild, and in tow, patchy. CT studies showed low attenuation, and MRA revealed mild vasospasm. The symptoms of all patients improved. Follow-up MRI in nine of 11 patients depicted complete resolution of the lesions ; in two, small infarctions remained but the extent of the lesions had decreased. Reversible posterior

  8. Rhodium(III)-Catalyzed ortho-Alkylation of Phenoxy Substrates with Diazo Compounds via C-H Activation: A Case of Decarboxylative Pyrimidine/Pyridine Migratory Cyclization Rather than Removal of Pyrimidine/Pyridine Directing Group.

    Science.gov (United States)

    Ravi, Manjula; Allu, Srinivasarao; Swamy, K C Kumara

    2017-03-03

    An efficient Rh(III)-catalyzed ortho-alkylation of phenoxy substrates with diazo compounds has been achieved for the first time using pyrimidine or pyridine as the directing group. Furthermore, bis-alkylation has also been achieved using para-substituted phenoxypyrimidine and 3 mol equiv of the diazo ester. The ortho-alkylated derivatives of phenoxy products possessing the ester functionality undergo decarboxylative pyrimidine/pyridine migratory cyclization (rather than deprotection of pyrimidine/pyridine group) using 20% NaOEt in EtOH affording a novel class of 3-(pyrimidin-2(1H)-ylidene)benzofuran-2(3H)-ones and 6-methyl-3-(pyridin-2(1H)-ylidene)benzofuran-2(3H)-one. The ortho-alkylated phenoxypyridine possessing ester functionality also undergoes decarboxylative pyridine migratory cyclization using MeOTf/NaOMe in toluene providing 6-methyl-3-(1-methylpyridin-2(1H)-ylidene)benzofuran-2(3H)-one.

  9. Intraoperative CT navigation for glenoid component fixation in reverse shoulder arthroplasty

    Directory of Open Access Journals (Sweden)

    Ashok S Gavaskar

    2013-01-01

    Full Text Available CT navigation has been shown to improve component positioning in total shoulder arthroplasty. The technique can be useful in achieving strong initial fixation of the metal backed glenoid in reverse shoulder arthroplasty. We report a 61 years male patient who underwent reverse shoulder arthroplasty for rotator cuff arthropathy. CT navigation was used intraoperatively to identify best possible glenoid bone and to maximize the depth of the fixation screws that anchor the metaglene portion of the metal backed glenoid component. Satisfactory positioning of screws and component was achieved without any perforation or iatrogenic fracture in the scapula. CT navigation can help in maximizing the purchase of the fixation screws that dictate the initial stability of the glenoid component in reverse shoulder arthroplasty. The technique can be extended to improve glenoid component position [version and tilt] with the availability of appropriate software.

  10. Cyclization of 1,2:3,4-di-O-isopropylidene-α-D-galacto-1,6-hexodialdo-1,5-pyranose acylhydrazone and semicarbazone

    OpenAIRE

    Martins Alho, Miriam Amelia; Baggio, Ricardo Fortunato; D'accorso, Norma Beatriz

    2015-01-01

    Cyclization of 1,2:3,4-di-O-isopropylidene-α-D-galacto-1,6-hexodialdo-1,5-pyranose benzoylhydrazone using acetylating mixtures led us to the corresponding (2R)- and (2S)-5- phenyl-1,3,4-oxadiazoline derivatives. The same conditions applied to the semicarbazone produced the 5-methyl-1,3,4-oxadiazoline derivative as the main compound, which is formed with acetylating mixtures even at room temperature. X-Ray analysis and NMR techniques were used to determine the stereochemistry of the new asymme...

  11. Direct Lactamization of Azido Amides via Staudinger-Type Reductive Cyclization

    Energy Technology Data Exchange (ETDEWEB)

    Heo, In Jung; Lee, Su Jeong; Cho, Chang Woo [Kyungpook National University, Daegu (Korea, Republic of)

    2012-01-15

    The direct lactamization of 1,3- and 1,4-azido amides has been achieved using triphenylphosphine and water, affording various γ- and δ-lactams in good to excellent yields. The direct lactamization of the azido amides was performed via the Staudinger-type reductive cyclization in which the amide group acts as the electrophile for lactam synthesis. This lactamization provides a mild, functional group tolerant and efficient route for the synthesis of various γ- and δ-lactams found in natural products and pharmaceuticals. Further studies will be conducted to develop new synthetic routes for the synthesis of various lactams. The lactam ring system is one of the most ubiquitous structural motifs found in natural products and pharmaceuticals. Owing to the prevalence of lactams, their synthesis has attracted considerable attention. Lactams are usually prepared by the coupling of activated carboxylic acid derivatives with amines. Alternative routes include the Beckmann rearrangement of oximes, the Schmidt reaction of cyclic ketones and hydrazoic acid, the Kinugasa reaction of nitrones and terminal acetylenes, the Diels-Alder reaction of cyclopentadiene and chlorosulfonyl isocyanate, transition metal catalyzed lactamization of amino alcohols, and iodolactamization of amides and alkenes. In particular, the intramolecular Staudinger ligation of azides and activated carboxy acids, including esters, is well known as an environmentally friendly and mild protocol for lactam synthesis.

  12. Direct Lactamization of Azido Amides via Staudinger-Type Reductive Cyclization

    International Nuclear Information System (INIS)

    Heo, In Jung; Lee, Su Jeong; Cho, Chang Woo

    2012-01-01

    The direct lactamization of 1,3- and 1,4-azido amides has been achieved using triphenylphosphine and water, affording various γ- and δ-lactams in good to excellent yields. The direct lactamization of the azido amides was performed via the Staudinger-type reductive cyclization in which the amide group acts as the electrophile for lactam synthesis. This lactamization provides a mild, functional group tolerant and efficient route for the synthesis of various γ- and δ-lactams found in natural products and pharmaceuticals. Further studies will be conducted to develop new synthetic routes for the synthesis of various lactams. The lactam ring system is one of the most ubiquitous structural motifs found in natural products and pharmaceuticals. Owing to the prevalence of lactams, their synthesis has attracted considerable attention. Lactams are usually prepared by the coupling of activated carboxylic acid derivatives with amines. Alternative routes include the Beckmann rearrangement of oximes, the Schmidt reaction of cyclic ketones and hydrazoic acid, the Kinugasa reaction of nitrones and terminal acetylenes, the Diels-Alder reaction of cyclopentadiene and chlorosulfonyl isocyanate, transition metal catalyzed lactamization of amino alcohols, and iodolactamization of amides and alkenes. In particular, the intramolecular Staudinger ligation of azides and activated carboxy acids, including esters, is well known as an environmentally friendly and mild protocol for lactam synthesis

  13. Nitrile anion cyclization with epoxysilanes followed by Brook rearrangement/ring-opening of cyclopropane nitriles/alkylation.

    Science.gov (United States)

    Okugawa, Seigo; Masu, Hyuma; Yamaguchi, Kentaro; Takeda, Kei

    2005-12-09

    [reactions: see text] The reaction of delta-silyl-gamma,delta-epoxypentanenitrile derivatives 9-12 with a base and an alkylating agent affords (Z)-delta-siloxy-gamma,delta-unsaturated pentanenitrile derivatives via a tandem process that involves the formation of a cyclopropane derivative by epoxy nitrile cyclization followed by Brook rearrangement and an anion-induced cleavage of the cyclopropane ring. Exclusive formation of a (Z)-derivative from trans-epoxides is explained by the reaction pathway that involves a backside displacement of the epoxide by the alpha-nitrile carbanion and the O-Si bond formation followed by concerted processes involving Brook rearrangement and the anti-mode of eliminative ring fission of the cyclopropane from the rotamer 19. The fact that (E)-isomers are exclusively obtained from cis-epoxides and alpha-cyclopropyl-alpha-silylcarbinol derivative 26 provides experimental support for the proposed pathway.

  14. Tandem Rh-Catalyzed Oxidative C-H Olefination and Cyclization of Enantiomerically Enriched Benzo-1,3-Sulfamidates: Stereoselective Synthesis of trans-1,3-Disubstituted Isoindolines.

    Science.gov (United States)

    Achary, Raghavendra; Jung, In-A; Lee, Hyeon-Kyu

    2018-04-06

    A tandem process, involving Rh(III)-catalyzed oxidative C-H olefination of enantiomerically enriched 4-aryl-benzo-1,3-sulfamidates and subsequent intramolecular aza-Michael cyclization has been developed. The reaction produces trans-benzosulfamidate-fused-1,3-disubstituted isoindolines as major products, in which the configurational integrity of the stereogenic center in the starting material is preserved. Further transformations of the benzosulfamidate-fused-1,3-disubstituted isoindolines are described.

  15. Synthesis of 3-substituted 4-piperidinones via a one-pot tandem oxidation-cyclization-oxidation process: stereodivergent reduction to 3,4-disubstituted piperidines.

    Science.gov (United States)

    Bahia, Perdip S; Snaith, John S

    2004-04-30

    A novel approach to 3-substituted 4-piperidinones is described. The one-pot tandem oxidation-cyclization-oxidation of unsaturated alcohols 1a-e by PCC or PCC and trifluoromethanesulfonic acid affords piperidinones 2a-e in good yield. Reduction of 2a-e by L-Selectride gives the corresponding cis 3,4-disubstituted piperidines with diastereomeric ratios of >99:1. By contrast, reduction of 2a-e by Al-isopropoxydiisobutylalane gives the trans products with diastereomeric ratios of up to 99:1.

  16. Synthesis of Cyclohexane-Fused Isocoumarins via Cationic Palladium(II)-Catalyzed Cascade Cyclization Reaction of Alkyne-Tethered Carbonyl Compounds Initiated by Intramolecular Oxypalladation of Ester-Substituted Aryl Alkynes.

    Science.gov (United States)

    Zhang, Jianbo; Han, Xiuling; Lu, Xiyan

    2016-04-15

    A cationic Pd(II)-catalyzed cascade cyclization reaction of alkyne-tethered carbonyl compounds was developed. This reaction is initiated by intramolecular oxypalladation of alkynes with an ester group followed by 1,2-addition of the formed C-Pd(II) bond to the carbonyl group, providing a highly efficient method for the synthesis of cyclohexane-fused isocoumarins.

  17. THE PRODUCTS OF THE CYCLIZING DEHYDRATION OF 1-BETA-PHENYLETHYLCYCLOHEXANOL-1 AND THE SYNTHESIS OF SPIROCYCLOHEXANE-1,1-INDANONE-3.

    Science.gov (United States)

    Levitz, M; Perlman, D; Bogert, M T

    1939-08-04

    (1) Spirocyclohexane-1,1-indanone (VI) has been found among the oxidation products of the hydrocarbon mixture which results when 1-beta-phenylethylcyclohexanol-1 is dehydrated, or when 1-beta-phenylethylcyclohexene is cyclized by aluminum trichloride, and its constitution has been proved by synthesis (2) Its oxime melts at 137-137.8 degrees (corr.). The oxime of m.p. 187.5 degrees , reported by Cook et al. therefore must be derived from some other ketone, perhaps the trans-ketoöctahydrophenanthrene, since we were unable to isolate any oxime of m.p. 177 degrees , the figure which they reported for this compound.

  18. Loop versus end colostomy reversal: has anything changed?

    Science.gov (United States)

    Bruns, B R; DuBose, J; Pasley, J; Kheirbek, T; Chouliaras, K; Riggle, A; Frank, M K; Phelan, H A; Holena, D; Inaba, K; Diaz, J; Scalea, T M

    2015-10-01

    Though primary repair of colon injuries is preferred, certain injury patterns require colostomy creation. Colostomy reversal is associated with significant morbidity and healthcare cost. Complication rates may be influenced by technique of diversion (loop vs. end colostomy), though this remains ill-defined. We hypothesized that reversal of loop colostomies is associated with fewer complications than end colostomies. This is a retrospective, multi-institutional study (four, level-1 trauma centers) of patients undergoing colostomy takedown for trauma during the time period 1/2006-12/2012. Data were collected from index trauma admission and subsequent admission for reversal and included demographics and complications of reversal. Student's t test was used to compare continuous variables against loop versus end colostomy. Discrete variables were compared against both groups using Chi-squared tests. Over the 6-year study period, 218 patients underwent colostomy takedown after trauma with a mean age of 30; 190 (87%) were male, 162 (74%) had penetrating injury as their indication for colostomy, and 98 (45%) experienced at least one complication. Patients in the end colostomy group (n = 160) were more likely to require midline laparotomy (145 vs. 18, p colostomy (n = 58). Local takedown of a loop colostomy is safe and leads to shorter hospital stays, less intra-operative blood loss, and fewer complications when compared to end colostomy.

  19. Reversible posterior leukoencephalopathy syndrome in children; MR imaging findings

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang Kwon; Kim, Yong Sun [Kyungpook National Univ. Taegu (Korea, Republic of); Kwon, Soon Hak [Ulsan Univ. College of Medicine, Seoul (Korea, Republic of)

    2001-02-01

    To find out the characteristic MR findings of reversible posterior leukoen-cephalopathy syndrome (RPLS) due to various causes in chldren. Eigh children with RPLS underwent MR imaging, and the findings were retrospectively analyzed. All eight were acutely hypertensive at the time of a neurotoxic episode. Three had intra-abdominal tumors (one adrenal pheochromo-cytoma, one para-aortic paraganglioma and one para-aortic ganglioneuroma encasing the left renal artery): three were being treated with cyclosporine: one was being treated with steroid: and one had hemolytric uremic syndrome. Initial cranial MR images were analyzed with particular emphasis on the distribution of the lesions. To assess possible sequelae, follow-up MR images were obtained in seven patients at least one week after the treatment of hypertension. Four underwent proton MR spectroscopy. Characteristic distribution of lesions in the occipital and posterior parietal lobes was identified in all cases regardless of the causes of RPLS. The cerebellum, basal ganglia, anterior parietal, and frontal lobe were involved in four, two, one, and one case, respectively. Cortical gray matter involvement was predominant in six and subcortical white matter involvement predominated in two patients. The distribution of lesions was bilateral and asymmetric. Gyriform enhancement was identified in six cases, and small hemorrhage was noted in one. In seven patients, the clinical and MR findings improved without sequelae on follow-up study. In one, proton MR spectroscopy demonstrated a high lactate peak at the time of the neurologic event. Nearnormal spectra were noted in three children who underwent proton MR spectroscopy after recovery. The MR findings of RPLS are characteristic in that lesions are distributed in the posterior region of the brain and they are reversible on follow-up study. In children with RPLS due to unknown causes, the possibility of intra-abdominal tumors should also be consiodered.

  20. Reversible posterior leukoencephalopathy syndrome in children; MR imaging findings

    International Nuclear Information System (INIS)

    Lee, Sang Kwon; Kim, Yong Sun; Kwon, Soon Hak

    2001-01-01

    To find out the characteristic MR findings of reversible posterior leukoen-cephalopathy syndrome (RPLS) due to various causes in chldren. Eigh children with RPLS underwent MR imaging, and the findings were retrospectively analyzed. All eight were acutely hypertensive at the time of a neurotoxic episode. Three had intra-abdominal tumors (one adrenal pheochromo-cytoma, one para-aortic paraganglioma and one para-aortic ganglioneuroma encasing the left renal artery): three were being treated with cyclosporine: one was being treated with steroid: and one had hemolytric uremic syndrome. Initial cranial MR images were analyzed with particular emphasis on the distribution of the lesions. To assess possible sequelae, follow-up MR images were obtained in seven patients at least one week after the treatment of hypertension. Four underwent proton MR spectroscopy. Characteristic distribution of lesions in the occipital and posterior parietal lobes was identified in all cases regardless of the causes of RPLS. The cerebellum, basal ganglia, anterior parietal, and frontal lobe were involved in four, two, one, and one case, respectively. Cortical gray matter involvement was predominant in six and subcortical white matter involvement predominated in two patients. The distribution of lesions was bilateral and asymmetric. Gyriform enhancement was identified in six cases, and small hemorrhage was noted in one. In seven patients, the clinical and MR findings improved without sequelae on follow-up study. In one, proton MR spectroscopy demonstrated a high lactate peak at the time of the neurologic event. Nearnormal spectra were noted in three children who underwent proton MR spectroscopy after recovery. The MR findings of RPLS are characteristic in that lesions are distributed in the posterior region of the brain and they are reversible on follow-up study. In children with RPLS due to unknown causes, the possibility of intra-abdominal tumors should also be consiodered

  1. A STUDY ON THE DEGRADATION MECHANISM OF PHOTOCROSSLINKING PRODUCTS FORMED BY CYCLIZED POLYISOPRENE-DIAZIDE SYSTEM UNDER THE INFLUENCE OF ALKYL BENZENE SULFONIC ACIDS

    Institute of Scientific and Technical Information of China (English)

    HUANG Junlian; SUN Meng

    1989-01-01

    The degradation mechanism of photocrosslinking products formed by cyclized polyisoprene-diazide system under the influence of the different alkyl benzene sulfonic acids was studied. The effects ofalkyl chain length and the concentration of alkyl benzene sulfonic acids on the rate of degradation reaction were discussed. It was found that in the initial stage of degradation, the cyclicity ratio and the average fused ring number did not change considerably, but the percentage of uncyclized parts content varied significantly. The suitable mechanism was supposed.

  2. Locked and proteolysis-based transcription activator-like effector (TALE) regulation.

    Science.gov (United States)

    Lonzarić, Jan; Lebar, Tina; Majerle, Andreja; Manček-Keber, Mateja; Jerala, Roman

    2016-02-18

    Development of orthogonal, designable and adjustable transcriptional regulators is an important goal of synthetic biology. Their activity has been typically modulated through stimulus-induced oligomerization or interaction between the DNA-binding and activation/repression domain. We exploited a feature of the designable Transcription activator-like effector (TALE) DNA-binding domain that it winds around the DNA which allows to topologically prevent it from binding by intramolecular cyclization. This new approach was investigated through noncovalent ligand-induced cyclization or through a covalent split intein cyclization strategy, where the topological inhibition of DNA binding by cyclization and its restoration by a proteolytic release of the topologic constraint was expected. We show that locked TALEs indeed have diminished DNA binding and regain full transcriptional activity by stimulation with the rapamycin ligand or site-specific proteolysis of the peptide linker, with much higher level of activation than rapamycin-induced heterodimerization. Additionally, we demonstrated reversibility, activation of genomic targets and implemented logic gates based on combinations of protein cyclization, proteolytic cleavage and ligand-induced dimerization, where the strongest fold induction was achieved by the proteolytic cleavage of a repression domain from a linear TALE. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

  3. Concise Stereocontrolled Formal Synthesis of (±)-Quinine and Total Synthesis of (±)-7-Hydroxyquinine via Merged Morita-Baylis-Hillman-Tsuji-Trost Cyclization

    Science.gov (United States)

    Webber, Peter; Krische, Michael J.

    2010-01-01

    Concise stereoselective syntheses of (±)-quinine and (±)-7-hydroxyquinine are achieved using a catalytic enone cycloallylation that combines the nucleophilic features of the Morita-Baylis-Hillman reaction and the electrophilic features of the Tsuji-Trost reaction. Cyclization of enone-allyl carbonate 11 delivers the product of cycloallylation 13 in 68% yield. Diastereoselective conjugate reduction of the enone 13 (>20:1 dr) followed by exchange of N-protecting groups provides the saturated N-Boc-protected methyl ketone 19, which upon aldol dehydration provides quinoline containing enone 15, possessing all carbon atoms of quinine. Exposure of ketone 15 to L-selectride enables diastereoselective carbonyl reduction (>20:1 dr) to furnish the allylic alcohol 16. Stereoselective hydroxyl-directed epoxidation using an oxovanadium catalyst modified by N-hydroxy-N-Me-pivalamide delivers epoxide 17 (17:1 dr). Cyclization of the resulting amine-epoxide 17 provides (±)-7-hydroxyquinine in 13 steps and 11% overall yield from aminoacetaldehyde diethyl acetal. Notably, highly stereoselective formation of five contiguous stereocenters is achieved through a series of 1,2-asymmetric induction events. A formal synthesis of (±)-quinine is achieved upon deoxygenation of the N-Cbz-protected allylic acetate 22 to provide olefin 23, which previously has been converted to quinine. Thus, (±)-quinine is accessible in 16 steps and 4% overall yield from commercial aminoacetaldehyde diethyl acetal, making this route the most concise approach to quinine, to date. PMID:18989927

  4. Rhodium(I)-catalyzed cyclization of allenynes with a carbonyl group through unusual insertion of a C-O bond into a rhodacycle intermediate.

    Science.gov (United States)

    Oonishi, Yoshihiro; Yokoe, Takayuki; Hosotani, Akihito; Sato, Yoshihiro

    2014-01-20

    Rhodium(I)-catalyzed cyclization of allenynes with a tethered carbonyl group was investigated. An unusual insertion of a CO bond into the C(sp(2) )-rhodium bond of a rhodacycle intermediate occurs via a highly strained transition state. Direct reductive elimination from the obtained rhodacyle intermediate proceeds to give a tricyclic product containing an 8-oxabicyclo[3.2.1]octane skeleton, while β-hydride elimination from the same intermediate gives products that contain fused five- and seven-membered rings in high yields. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Increased follicle-stimulating hormone is associated with higher assisted reproduction use after vasectomy reversal.

    Science.gov (United States)

    Hsiao, Wayland; Sultan, Raymond; Lee, Richard; Goldstein, Marc

    2011-06-01

    Of men with vasectomy 6% elect to have more children. When considering vasectomy reversal vs in vitro fertilization/intracytoplasmic sperm injection, an elucidation of preoperative factors that predict surgical success would help determine appropriate management. We tested the hypothesis that preoperative follicle-stimulating hormone 10 U/l or greater predict a lower paternity rate after vasectomy reversal. Using preoperative follicle-stimulating hormone levels we retrospectively reviewed the records of patients who underwent vasectomy reversal. Follicle-stimulating hormone was measured in cases suspicious for impaired spermatogenesis. The final analysis included 206 men, who were divided by follicle-stimulating hormone less than 10 U/l (normal in 155) and 10 U/l or greater (high in 51). Nominal logistic regression was performed to evaluate assisted reproduction predictors. Mean ± SD follicle-stimulating hormone in the normal and high groups was 5.1 ± 2.2 and 16.2 ± 6.2 U/l, respectively. Postoperative semen parameters were similar. However, in the high hormone group there was greater use of any type of assisted reproduction (78.4% vs 54.8%, p = 0.0028). On multivariate analysis follicle-stimulating hormone 10 U/l or greater (OR 3.02, 95% CI 1.34-6.83) and vasoepididymostomy that was bilateral or to a solitary testis (OR 3.26, 95% CI 1.09-9.69) was associated with greater assisted reproduction use. We evaluated preoperative follicle-stimulating hormone as a predictor of reproductive outcome in men with suspected subfertility who underwent vasectomy reversal. Increased follicle-stimulating hormone was associated with a higher rate of assisted reproduction even after controlling for confounding covariates. Thus, men with increased follicle-stimulating hormone should be counseled on the increased likelihood of needing assisted reproduction to achieve pregnancy after vasectomy reversal. Copyright © 2011 American Urological Association Education and Research, Inc

  6. Selectivity switch in the synthesis of vinylgold(I) intermediates

    KAUST Repository

    Hashmi, A. Stephen K

    2011-11-28

    An unexpected regioselectivity reversal was observed in the synthesis of vinylgold(I) complexes from propargyl carboxamides. The use of [Au(IPr)(OH)] affords preferentially vinylgold(I) complexes resulting from a 5-exo-dig cyclization, whereas the use [Au(IPr)]+ species, generated in situ starting from [Au(IPr)(Cl)] and AgOTf, leads to vinylgold(I) complexes which form via a 6-endo-dig cyclization, This unexpected "selectivity switch" for this cyclization led us to propose two different reaction pathways enabling the formation of the two different products. One mechanism involves the [Au(IPr)]+ species with "classical" I activation of the alkyne framework of the carboxamides, and the second represents an "unusual" use of the basic Brønsted character of [Au(IPr)(OH)]. Mechanistic and DFT studies support the mechanistic hypotheses. © 2011 American Chemical Society.

  7. Selectivity switch in the synthesis of vinylgold(I) intermediates

    KAUST Repository

    Hashmi, A. Stephen K; Schuster, Andreas M.; Gaillard, Sylvain; Cavallo, Luigi; Poater, Albert; Nolan, Steven P.

    2011-01-01

    An unexpected regioselectivity reversal was observed in the synthesis of vinylgold(I) complexes from propargyl carboxamides. The use of [Au(IPr)(OH)] affords preferentially vinylgold(I) complexes resulting from a 5-exo-dig cyclization, whereas the use [Au(IPr)]+ species, generated in situ starting from [Au(IPr)(Cl)] and AgOTf, leads to vinylgold(I) complexes which form via a 6-endo-dig cyclization, This unexpected "selectivity switch" for this cyclization led us to propose two different reaction pathways enabling the formation of the two different products. One mechanism involves the [Au(IPr)]+ species with "classical" I activation of the alkyne framework of the carboxamides, and the second represents an "unusual" use of the basic Brønsted character of [Au(IPr)(OH)]. Mechanistic and DFT studies support the mechanistic hypotheses. © 2011 American Chemical Society.

  8. Effect of thallium-201 blood levels on reversible myocardial defects

    International Nuclear Information System (INIS)

    Nelson, C.W.; Wilson, R.A.; Angello, D.A.; Palac, R.T.

    1989-01-01

    To determine if 201 Tl plasma blood levels correlate with the presence of reversible myocardial defects during exercise testing, 14 patients with stable coronary artery disease underwent two separate exercise 201 Tl stress tests. Between initial and delayed imaging, on one test the patients drank an instant breakfast drink (eating) and on the other they drank an equivalent volume of water as a control (H 2 O). Thallium-201 imaging was performed immediately postexercise, immediately after eating/H 2 O and 210 min after eating/H 2 O. Between initial and immediate post eating/H 2 O images 201Tl reversible defects occurred in 27/38 regions in the H 2 O test versus 15/38 regions in the eating test (p = 0.02). Over this early time period, plasma 201 Tl activity was significantly higher in the H 2 O test than eating test (p less than 0.05). In conclusion, early reversal of 201 Tl defects may, in part, be the result of higher plasma 201 Tl activity early after initial postexercise 201 Tl imaging

  9. Fluoroscopically Guided Transcervical Fallopian Tube Recanalization of Post-Sterilization Reversal Mid-Tubal Obstructions

    International Nuclear Information System (INIS)

    Houston, J. Graeme; Anderson, David; Mills, John; Harrold, Anthony

    2000-01-01

    Purpose: To assess the technical success and early outcome of fluoroscopically guided transcervical fallopian tube recanalization (FTR) in mid-tubal occlusion following sterilization reversal surgery.Methods: From July 1995 to January 1998, patients with greater than 12 months secondary infertility underwent hysterosalpingography (HSG). FTR was performed in proximal or mid-tubal occlusion. Cases of FTR in mid-tubal occlusion were included in this study. Technical success (defined as complete tubal patency) using a standard guidewire and hydrophilic glidewire, the number of patients with at least one patent tube, and the intrauterine and ectopic pregnancy rates were determined.Results: Twenty-six infertile patients with previous sterilization reversal underwent HSG. Eight of 26 (31%) patients (mean age 32 years, range 23-37 years), had attempted FTR for mid-tubal occlusion at the site of surgical anastomosis. Fourteen tubes were attempted as there were two previous salpingectomies. Technical success was achieved in eight of 14 (57%) tubes attempted, resulting in five of eight (62%) patients having at least one patent tube. At follow-up (mean 18 months, range 12-28 months) in these five patients there was one intrauterine pregnancy. There were no ectopic pregnancies.Conclusions: FTR in mid-tubal obstruction in infertile patients following sterilization reversal surgery is technically feasible and may result in intrauterine pregnancy. In this small group there was a lower technical success rate and lower pregnancy rate than in unselected proximal tubal occlusion

  10. Pd(II)-Catalyzed Hydroxyl-Directed C–H Olefination Enabled by Mono-Protected Amino Acid Ligands

    Science.gov (United States)

    Lu, Yi; Wang, Dong-Hui; Engle, Keary M.

    2010-01-01

    A novel Pd(II)-catalyzed ortho-C–H olefination protocol has been developed using spatially remote, unprotected tertiary, secondary, and primary alcohols as the directing groups. Mono-N-protected amino acid ligands were found to promote the reaction, and an array of olefin coupling partners could be used. When electron-deficient alkenes were used, the resulting olefinated intermediates underwent subsequent Pd(II)-catalyzed oxidative intramolecular cyclization to give the corresponding pyran products, which could be converted into ortho-alkylated alcohols under hydrogenolysis conditions. The mechanistic details of the oxidative cyclization step are discussed and situated in the context of the overall catalytic cycle. PMID:20359184

  11. Assembly of Four Diverse Heterocyclic Libraries Enabled by Prins Cyclization, Au-Catalyzed Enyne Cycloisomerization, and Automated Amide Synthesis

    Science.gov (United States)

    Cui, Jiayue; Chai, David I.; Miller, Christopher; Hao, Jason; Thomas, Christopher; Wang, JingQi; Scheidt, Karl A.; Kozmin, Sergey A.

    2013-01-01

    We describe a unified synthetic strategy for efficient assembly of four new heterocyclic libraries. The synthesis began by creating a range of structurally diverse pyrrolidinones or piperidinones. Such compounds were obtained in a simple one-flask operation starting with readily available amines, ketoesters, and unsaturated anhydrides. The use of tetrahydropyran-containing ketoesters, which were rapidly assembled by our Prins cyclization protocol, enabled efficient fusion of pyran and piperidinone cores. A newly developed Au(I)-catalyzed cycloisomerization of alkyne-containing enamides further expanded heterocyclic diversity by providing rapid entry into a wide range of bicyclic and tricyclic dienamides. The final stage of the process entailed diversification of each of the initially produced carboxylic acids using a fully automated platform for amide synthesis, which delivered 1872 compounds in high diastereomeric and chemical purity. PMID:22860634

  12. On-Surface Pseudo-High-Dilution Synthesis of Macrocycles: Principle and Mechanism.

    Science.gov (United States)

    Fan, Qitang; Wang, Tao; Dai, Jingya; Kuttner, Julian; Hilt, Gerhard; Gottfried, J Michael; Zhu, Junfa

    2017-05-23

    Macrocycles have attracted much attention due to their specific "endless" topology, which results in extraordinary properties compared to related linear (open-chain) molecules. However, challenges still remain in their controlled synthesis with well-defined constitution and geometry. Here, we report the successful application of the (pseudo-)high-dilution method to the conditions of on-surface synthesis in ultrahigh vacuum. This approach leads to high yields (up to 84%) of cyclic hyperbenzene ([18]-honeycombene) via an Ullmann-type reaction from 4,4″-dibromo-meta-terphenyl (DMTP) as precursor on a Ag(111) surface. The mechanism of macrocycle formation was explored in detail using scanning tunneling microscopy and X-ray photoemission spectroscopy. We propose that the dominant pathway for hyperbenzene (MTP) 6 formation is the stepwise desilverization of an organometallic (MTP-Ag) 6 macrocycle, which forms via cyclization of (MTP-Ag) 6 chains under pseudo-high-dilution conditions. The high probability of cyclization on the stage of the organometallic phase results from the reversibility of the C-Ag bond. The case is different from that in solution, in which cyclization typically occurs on the stage of a covalently bonded open-chain precursor. This difference in the cyclization mechanism on a surface compared to that in solution stems mainly from the 2D confinement exerted by the surface template, which hinders the flipping of chain segments necessary for cyclization.

  13. Use of Elemental Sulfur or Selenium in a Novel One-Pot Copper-Catalyzed Tandem Cyclization of Functionalized Ynamides Leading to Benzosultams.

    Science.gov (United States)

    Siva Reddy, Alla; Kumara Swamy, K C

    2015-06-19

    A novel and efficient [Cu]-catalyzed one-pot regio- and stereospecific synthesis of benzo[1,4,2]dithiazine 1,1-dioxides and benzo[1,4,2]thiaselenazine 1,1-dioxides by cyclization of functionalized ynamides with elemental sulfur/selenium has been developed. Its generality is elegantly illustrated by extension to benzodithiazepines and benzothiaselenazepines. Involvement of water in the reaction is demonstrated by the incorporation of (2)D at the olefinic site by using D2O in place of water. Selective oxidation at sulfur in benzo[1,4,2]dithiazine 1,1-dioxide by using mCPBA as the oxidizing agent is also described.

  14. Obesity-related hypogonadism: a reversible condition.

    Science.gov (United States)

    Zouras, Stamatios; Stephens, Jeffrey W; Price, David

    2017-06-23

    Obesity is associated with hypogonadism. While this association is widely accepted, the underlying mechanisms remain unclear. Furthermore, obesity is a risk factor for hypogonadism and conversely hypogonadism may be a risk factor for obesity. We present the case of a morbidly obese man aged 30 years with hypogonadotrophic hypogonadism that underwent a Roux-en-Y gastric bypass operation. Following the surgical treatment of his obesity, the testosterone level returned to normal with improvements in hypogonadal symptoms, which allowed discontinuation of exogenous testosterone therapy. This case report demonstrates reversal of hypogonadism following weight loss with restoration of gonadal function. © BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  15. Reversible flowchart languages and the structured reversible program theorem

    DEFF Research Database (Denmark)

    Yokoyama, Tetsuo; Axelsen, Holger Bock; Glück, Robert

    2008-01-01

    Many irreversible computation models have reversible counterparts, but these are poorly understood at present. We introduce reversible flowcharts with an assertion operator and show that any reversible flowchart can be simulated by a structured reversible flowchart using only three control flow...... operators. Reversible flowcharts are r- Turing-complete, meaning that they can simuluate reversible Turing machines without garbage data. We also demonstrate the injectivization of classical flowcharts into reversible flowcharts. The reversible flowchart computation model provides a theoretical...

  16. Late reversibility of tomographic myocardial thallium-201 defects: an accurate marker of myocardial viability

    International Nuclear Information System (INIS)

    Kiat, H.; Berman, D.S.; Maddahi, J.; De Yang, L.; Van Train, K.; Rozanski, A.; Friedman, J.

    1988-01-01

    Twenty-one patients were studied who underwent thallium-201 stress-redistribution single photon emission computed tomography (SPECT) both before and after coronary artery bypass grafting (n = 15) or transluminal coronary angioplasty (n = 6). All patients underwent thallium imaging 15 min, 4 h and late (18 to 72 h) after stress as part of the preintervention thallium-201 scintigram. In a total of 201 tomographic myocardial segments with definite post-stress thallium-201 perfusion defects in which the relevant coronary arteries were subsequently successfully reperfused, the 4 h redistribution images did not predict the postintervention scintigraphic improvement: 67 (85%) of the 79 4 h reversible as well as 88 (72%) of the 122 4 h nonreversible segments improved (p = NS). The 18 to 72 h late redistribution images effectively subcategorized the 4 h nonreversible segments with respect to postintervention scintigraphic improvement: 70 (95%) of the 74 late reversible segments improved after intervention, whereas only 18 (37%) of the 48 late nonreversible segments improved (p less than 0.0001). The frequency of late reversible defects and the frequency of postrevascularization improvement of late nonreversible defects are probably overestimated by this study because of referral biases. The cardiac counts and target to background ratios from late redistribution studies resulted in satisfactory cardiac images for visual interpretation. For optimal assessment of the extent of viable myocardium by thallium-201 scintigraphic studies, late redistribution imaging should be performed when nonreversible defects are observed on 4 h redistribution images

  17. Gallium-67-labeled lactam bridge-cyclized alpha-melanocyte stimulating hormone peptide for primary and metastatic melanoma imaging.

    Science.gov (United States)

    Guo, Haixun; Yang, Jianquan; Shenoy, Nalini; Miao, Yubin

    2009-12-01

    The purpose of this study was to examine the melanoma imaging properties of a novel 67Ga-labeled lactam bridge-cyclized alpha-melanocyte stimulating hormone (alpha-MSH) peptide. A lactam bridge-cyclized alpha-MSH peptide, DOTA-GlyGlu-CycMSH {DOTA-Gly-Glu-c[Lys-Nle-Glu-His-DPhe-Arg-Trp-Gly-Arg-Pro-Val-Asp]}, was synthesized and radiolabeled with 67Ga. The melanoma targeting and pharmacokinetic properties of 67Ga-DOTA-GlyGlu-CycMSH were determined in B16/F1 flank primary melanoma-bearing and B16/F10 pulmonary metastatic melanoma-bearing C57 mice. Flank primary melanoma and pulmonary metastatic melanoma imaging were performed by small animal single photon emission computed tomography (SPECT)/CT using 67Ga-DOTA-GlyGlu-CycMSH as an imaging probe. 67Ga-DOTA-GlyGlu-CycMSH was readily prepared with greater than 95% radiolabeling yield. 67Ga-DOTA-GlyGlu-CycMSH exhibited substantial tumor uptake (12.93 +/- 1.63%ID/g at 2 h postinjection) and prolonged tumor retention (5.02 +/- 1.35%ID/g at 24 h postinjection) in B16/F1 melanoma-bearing C57 mice. The uptake values for nontarget organs were generally low (<0.30%ID/g) except for the kidneys at 2, 4, and 24 h postinjection. 67Ga-DOTA-GlyGlu-CycMSH exhibited significantly (p < 0.05) higher uptakes (1.44 +/- 0.75%ID/g at 2 h postinjection and 1.49 +/- 0.69%ID/g at 4 h postinjection) in metastatic melanoma-bearing lung than those in normal lung (0.15 +/- 0.10%ID/g and 0.17 +/- 0.11%ID/g at 2 and 4 h postinjection, respectively). Both flank primary B16/F1 melanoma and B16/F10 pulmonary melanoma metastases were clearly visualized by SPECT/CT using 67Ga-DOTA-GlyGlu-CycMSH as an imaging probe 2 h postinjection. 67Ga-DOTA-GlyGlu-CycMSH exhibited favorable melanoma targeting and imaging properties, highlighting its potential as an effective imaging probe for early detection of primary and metastatic melanoma.

  18. Transcriptome analysis of Pinus massoniana Lamb. microstrobili during sexual reversal

    Directory of Open Access Journals (Sweden)

    Feng Xiao

    2018-04-01

    Full Text Available The normal megastrobilli and microstrobilli before and after the sexual reversal in Pinus massoniana Lamb. were studied and classified using a transcriptomic approach. In the analysis, a total of 190,023 unigenes were obtained with an average length of 595 bp. The annotated unigenes were divided into 56 functional groups and 130 metabolic pathways involved in the physiological and biochemical processes related to ribosome biogenesis, carbon metabolism, and amino acid biosynthesis. Analysis revealed 4,758 differentially expressed genes (DEGs between the mega- and microstrobili from the polycone twig. The DEGs between the mega- and microstrobili from the normal twig were 5,550. In the polycone twig, 1,188 DEGs were identified between the microstrobili and the sexually reversed megastrobili. Concerning plant hormone signal transduction pathways, the DEGs from both the normal and polycone twigs displayed distinct male or female associated expression patterns. There were 36 common hormone-related DEGs from the two types of twigs of P. massoniana. Interestingly, expression of these DEGs was up-regulated in the bisexual strobili, which underwent the sexual reversal. A portion of MADS-box genes in the bisexual strobili were up-regulated relative to expression in microstrobili.

  19. Bioorthogonal cyclization-mediated in situ self-assembly of small-molecule probes for imaging caspase activity in vivo

    Science.gov (United States)

    Ye, Deju; Shuhendler, Adam J.; Cui, Lina; Tong, Ling; Tee, Sui Seng; Tikhomirov, Grigory; Felsher, Dean W.; Rao, Jianghong

    2014-06-01

    Directed self-assembly of small molecules in living systems could enable a myriad of applications in biology and medicine, and already this has been used widely to synthesize supramolecules and nano/microstructures in solution and in living cells. However, controlling the self-assembly of synthetic small molecules in living animals is challenging because of the complex and dynamic in vivo physiological environment. Here we employ an optimized first-order bioorthogonal cyclization reaction to control the self-assembly of a fluorescent small molecule, and demonstrate its in vivo applicability by imaging caspase-3/7 activity in human tumour xenograft mouse models of chemotherapy. The fluorescent nanoparticles assembled in situ were imaged successfully in both apoptotic cells and tumour tissues using three-dimensional structured illumination microscopy. This strategy combines the advantages offered by small molecules with those of nanomaterials and should find widespread use for non-invasive imaging of enzyme activity in vivo.

  20. trans-2-Tritylcyclohexanol as a chiral auxiliary in permanganate-mediated oxidative cyclization of 2-methylenehept-5-enoates: application to the synthesis of trans-(+)-linalool oxide.

    Science.gov (United States)

    Al Hazmi, Ali M; Sheikh, Nadeem S; Bataille, Carole J R; Al-Hadedi, Azzam A M; Watkin, Sam V; Luker, Tim J; Camp, Nicholas P; Brown, Richard C D

    2014-10-03

    The permanganate-mediated oxidative cyclization of a series of 2-methylenehept-5-eneoates bearing different chiral auxiliaries was investigated, leading to the discovery of trans-2-tritylcyclohexanol (TTC) as a highly effective chiral controller for the formation of the 2,5-substituted THF diol product with high diastereoselectivity (dr ∼97:3). Chiral resolution of (±)-TTC, prepared in one step from cyclohexene oxide, afforded (-)-(1S,2R)-TTC (er >99:1), which was applied to the synthesis of (+)-trans-(2S,5S)-linalool oxide.

  1. Segmental reversal of distal small intestine in short bowel syndrome

    DEFF Research Database (Denmark)

    Grave, Pernille Kock; Thomsen, Sabrina Valentin; Clark, Pia Susanne

    2018-01-01

    were the influence on cell proliferation and mucosal architecture shown by histological analysis. Methods: Sixteen piglets underwent a 60% resection of the distal small intestine and were randomized into two groups. Group 1 short bowel syndrome alone (SBS) (n = 8) and group 2 with reversal of a distal...... small intestinal segment (SBS-RS) (n = 8). Body weight was measured daily and the pigs were euthanized after 1 month. Crypt depths, villus heights and muscle layers thicknesses were measured. For the evaluation of microvilli of the brush border of the epithelium and cell proliferation...... was found in the SBS group and increase in the thickness of the circular and longitudinal muscle layers in the SBS-RS group. In the distal ileal segment the longitudinal muscle layer thicknesses were increased in the SBS group. Otherwise, no significant changes were found. Conclusion: Reversal of a 20-cm...

  2. Reverse Algols

    Science.gov (United States)

    Leung, K. C.

    1989-01-01

    Reverse Algols, binary systems with a semidetached configuration in which the more massive component is in contact with the critical equipotential surface, are examined. Observational evidence for reverse Algols is presented and the parameters of seven reverse Algols are listed. The evolution of Algols and reverse Algols is discussed. It is suggested that, because reverse Algols represent the premass-reversal semidetached phase of close binary evolution, the evolutionary time scale between regular and reverse Algols is the ratio of the number of confirmed systems of these two Algol types.

  3. A Novel Synthesis of 1-Acetyl-4-Isopropenyl-1-Cyclopentene by Chemoselective Cyclization of 4-Methyl-3-(Oxobutyl-4-Pentenal: An Important Intermediate for Natural Product Synthesis

    Directory of Open Access Journals (Sweden)

    Castro Fernando de Lima

    1999-01-01

    Full Text Available This article presents the direct oxidation of limonene-oxide 1 with KIO4 in water, which is the best way to obtain the keto-aldehyde 3, an important intermediate in natural product synthesis. The cyclization of keto-aldehyde 3 with acidic Al2O3 proceeds chemoselectively to give ketone 4. These two reactions together increase the overall yield of ketone 4 to about 70% compared to 8% previously reported in the literature¹.

  4. Reversible defects on myocardial perfusion imaging early after coronary stent implantation: a predictor of late restenosis

    International Nuclear Information System (INIS)

    Kim, D. E.; Park, S. A.; Kim, C. K.; Chang, J. A.; Jeong, J. W.; Oh, S. G.; Lee, C.

    2007-01-01

    It appears logical that myocardial perfusion should be fixed and not reversible, in the territory supplied by a dilated coronary artery. However, several studies have demonstrated reversible perfusion in the territory supplied by a coronary artery with an optimally implanted stent. The main objective of this study was to evaluate the incidence of reversible defects detected by M-SPECT early after optimal PTCA with stent implantation. Its second objective was to determine the predictive value of detecting reversible defects after stent implantation for late restenosis. Sixty-six patients that underwent M-SPECT within 24 hours of successful PTCA with stent implantation were included. All patients were followed up clinically and angiographically. The incidence of reversible perfusion defects on M-SPECT and the rate of late restenosis in target coronary arteries were evaluated retrospectively. Reversible perfusion defects on M-SPECT were observed in 26% of the patients and in 36% of lesions following successful PTCA with stent implantation. The incidence of late restenosis was significantly higher in patients and lesions with reversible perfusion defects (47% vs. 18%). According to binary logistic regression analysis, the presence of a reversible perfusion defects was the only independent predictor of late restenosis. This study shows that the predictive value of reversible perfusion defects on M-SPECT early after stent implantation with respect to the incidence of late restenosis was 47% in patients with a reversible defect, and 18% in those without it

  5. Evolution of elderly patients who underwent cardiac surgery with cardiopulmonary bypass

    Directory of Open Access Journals (Sweden)

    Alain Moré Duarte

    2016-01-01

    Full Text Available Introduction: There is a steady increase in the number of elderly patients with severe cardiovascular diseases who require a surgical procedure to recover some quality of life that allows them a socially meaningful existence, despite the risks.Objectives: To analyze the behavior of elderly patients who underwent cardiac surgery with cardiopulmonary bypass.Method: A descriptive, retrospective, cross-sectional study was conducted with patients over 65 years of age who underwent surgery at the Cardiocentro Ernesto Che Guevara, in Santa Clara, from January 2013 to March 2014.Results: In the study, 73.1% of patients were men; and there was a predominance of subjects between 65 and 70 years of age, accounting for 67.3%. Coronary artery bypass graft was the most prevalent type of surgery and had the longest cardiopulmonary bypass times. Hypertension was present in 98.1% of patients. The most frequent postoperative complications were renal dysfunction and severe low cardiac output, with 44.2% and 34.6% respectively.Conclusions: There was a predominance of men, the age group of 65 to 70 years, hypertension, and patients who underwent coronary artery bypass graft with prolonged cardiopulmonary bypass. Renal dysfunction was the most frequent complication.

  6. [(PhCH2O2P(CH32CHNCH(CH32]2PdCl2/CuI as Cocatalyst for Coupling-Cyclization of 2-Iodophenol with Terminal Alkynes in Water

    Directory of Open Access Journals (Sweden)

    Panli Jiang

    2018-03-01

    Full Text Available A new and efficient [(PhCH2O2P(CH32CHNCH(CH32]2PdCl2/CuI-co-catalyzed coupling-cyclization reactions of 2-iodophenol with terminal alkynes is described. Different 2-substitued benzo[b]furan derivatives are obtained in good to excellent yields. This protocol employs a relatively low palladium(II catalyst loading in water under air conditions.

  7. Managing Reverse Logistics or Reversing Logistics Management?

    OpenAIRE

    Brito, Marisa

    2004-01-01

    textabstractIn the past, supply chains were busy fine-tuning the logistics from raw material to the end customer. Today an increasing flow of products is going back in the chain. Thus, companies have to manage reverse logistics as well.This thesis contributes to a better understanding of reverse logistics. The thesis brings insights on reverse logistics decision-making and it lays down theoretical principles for reverse logistics as a research field.In particular it puts together a framework ...

  8. General and Facile Route to Isomerically Pure Tricyclic Peptides Based on Templated Tandem CLIPS/CuAAC Cyclizations.

    Science.gov (United States)

    Richelle, Gaston J J; Ori, Sumeet; Hiemstra, Henk; van Maarseveen, Jan H; Timmerman, Peter

    2018-01-08

    We report a one-pot ligation/cyclization technology for the rapid and clean conversion of linear peptides into tricyclic peptides that is based on using tetravalent scaffolds containing two benzyl bromide and two alkyne moieties. These react via CLIPS/CuAAC reactions with cysteines and azides in the peptide. Flexibility in the scaffolds is key to the formation of isomerically pure products as the flexible scaffolds T4 1 and T4 2 mostly promote the formation of single isomeric tricycles while the rigid scaffolds T4 3 and T4 4 do not yield clean products. There seems to be no limitation to the number and types of amino acids present as 18 canonical amino acids were successfully implemented. We also observed that azides at the peptide termini and cysteine residues in the center gave better results than compounds with the functional groups placed the other way round. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Serum Zn levels in dysphagic patients who underwent endoscopic gastrostomy for long term enteral nutrition

    OpenAIRE

    Adriana Santos, Carla; Fonseca, Jorge; Brito, José; Fernandes, Tânia; Gonçalves, Luísa; Sousa Guerreiro, António

    2014-01-01

    Background and aims: Dysphagic patients who underwent endoscopic gastrostomy (PEG) usually present protein-energy malnutrition, but little is known about micronutrient malnutrition. The aim of the present study was the evaluation of serum zinc in patients who underwent endoscopic gastrostomy and its relationship with serum proteins, whole blood zinc, and the nature of underlying disorder. Methods: From patients that underwent gastrostomy a blood sample was obtained minutes before the procedur...

  10. Reverse Logistics

    OpenAIRE

    Kulikova, Olga

    2016-01-01

    This thesis was focused on the analysis of the concept of reverse logistics and actual reverse processes which are implemented in mining industry and finding solutions for the optimization of reverse logistics in this sphere. The objective of this paper was the assessment of the development of reverse logistics in mining industry on the example of potash production. The theoretical part was based on reverse logistics and mining waste related literature and provided foundations for further...

  11. Preoperative warfarin reversal for early hip fracture surgery.

    Science.gov (United States)

    Moores, Thomas Steven; Beaven, Alastair; Cattell, Andrew Edwin; Baker, Charles; Roberts, Philip John

    2015-04-01

    To evaluate our hospital protocol of low-dose vitamin K titration for preoperative warfarin reversal for early hip fracture surgery. Records of 16 men and 33 women aged 63 to 93 (mean, 81) years who were taking warfarin for atrial fibrillation (n=40), venous thromboembolism (n=9), cerebrovascular accident (n=3), and prosthetic heart valve (n=3) and underwent surgery for hip fractures were reviewed. The 3 patients with a prosthetic heart valve were deemed high risk for thromboembolism and the remainder low-risk. The international normalised ratio (INR) of patients was checked on admission and 6 hours after administration of vitamin K; an INR of fracture surgery within 36 to 48 hours of admission improves morbidity and mortality.

  12. Seizure-induced brain lesions: A wide spectrum of variably reversible MRI abnormalities

    International Nuclear Information System (INIS)

    Cianfoni, A.; Caulo, M.; Cerase, A.; Della Marca, G.; Falcone, C.; Di Lella, G.M.; Gaudino, S.; Edwards, J.; Colosimo, C.

    2013-01-01

    Introduction MRI abnormalities in the postictal period might represent the effect of the seizure activity, rather than its structural cause. Material and Methods Retrospective review of clinical and neuroimaging charts of 26 patients diagnosed with seizure-related MR-signal changes. All patients underwent brain-MRI (1.5-Tesla, standard pre- and post-contrast brain imaging, including DWI-ADC in 19/26) within 7 days from a seizure and at least one follow-up MRI, showing partial or complete reversibility of the MR-signal changes. Extensive clinical work-up and follow-up, ranging from 3 months to 5 years, ruled out infection or other possible causes of brain damage. Seizure-induced brain-MRI abnormalities remained a diagnosis of exclusion. Site, characteristics and reversibility of MRI changes, and association with characteristics of seizures were determined. Results MRI showed unilateral (13/26) and bilateral abnormalities, with high (24/26) and low (2/26) T2-signal, leptomeningeal contrast-enhancement (2/26), restricted diffusion (9/19). Location of abnormality was cortical/subcortical, basal ganglia, white matter, corpus callosum, cerebellum. Hippocampus was involved in 10/26 patients. Reversibility of MRI changes was complete in 15, and with residual gliosis or focal atrophy in 11 patients. Reversibility was noted between 15 and 150 days (average, 62 days). Partial simple and complex seizures were associated with hippocampal involvement (p = 0.015), status epilepticus with incomplete reversibility of MRI abnormalities (p = 0.041). Conclusions Seizure or epileptic status can induce transient, variably reversible MRI brain abnormalities. Partial seizures are frequently associated with hippocampal involvement and status epilepticus with incompletely reversible lesions. These seizure-induced MRI abnormalities pose a broad differential diagnosis; increased awareness may reduce the risk of misdiagnosis and unnecessary intervention

  13. Seizure-induced brain lesions: A wide spectrum of variably reversible MRI abnormalities

    Energy Technology Data Exchange (ETDEWEB)

    Cianfoni, A., E-mail: acianfoni@hotmail.com [Neuroradiology, Neurocenter of Italian Switzerland–Ospedale regionale Lugano, Via Tesserete 46, Lugano, 6900, CH (Switzerland); Caulo, M., E-mail: caulo@unich.it [Department of Neuroscience and Imaging, University of Chieti, Via dei Vestini 33, 6610 Chieti. Italy (Italy); Cerase, A., E-mail: alfonsocerase@gmail.com [Unit of Neuroimaging and Neurointervention NINT, Department of Neurological and Sensorineural Sciences, Azienda Ospedaliera Universitaria Senese, Policlinico “Santa Maria alle Scotte”, V.le Bracci 16, Siena (Italy); Della Marca, G., E-mail: dellamarca@rm.unicatt.it [Neurology Dept., Catholic University of Rome, L.go F Vito 1, 00100, Rome (Italy); Falcone, C., E-mail: carlo_falc@libero.it [Radiology Dept., Catholic University of Rome, L.go F Vito 1, 00100, Rome (Italy); Di Lella, G.M., E-mail: gdilella@rm.unicatt.it [Radiology Dept., Catholic University of Rome, L.go F Vito 1, 00100, Rome (Italy); Gaudino, S., E-mail: sgaudino@sirm.org [Radiology Dept., Catholic University of Rome, L.go F Vito 1, 00100, Rome (Italy); Edwards, J., E-mail: edwardjc@musc.edu [Neuroscience Dept., Medical University of South Carolina, 96J Lucas st, 29425, Charleston, SC (United States); Colosimo, C., E-mail: colosimo@rm.unicatt.it [Radiology Dept., Catholic University of Rome, L.go F Vito 1, 00100, Rome (Italy)

    2013-11-01

    Introduction MRI abnormalities in the postictal period might represent the effect of the seizure activity, rather than its structural cause. Material and Methods Retrospective review of clinical and neuroimaging charts of 26 patients diagnosed with seizure-related MR-signal changes. All patients underwent brain-MRI (1.5-Tesla, standard pre- and post-contrast brain imaging, including DWI-ADC in 19/26) within 7 days from a seizure and at least one follow-up MRI, showing partial or complete reversibility of the MR-signal changes. Extensive clinical work-up and follow-up, ranging from 3 months to 5 years, ruled out infection or other possible causes of brain damage. Seizure-induced brain-MRI abnormalities remained a diagnosis of exclusion. Site, characteristics and reversibility of MRI changes, and association with characteristics of seizures were determined. Results MRI showed unilateral (13/26) and bilateral abnormalities, with high (24/26) and low (2/26) T2-signal, leptomeningeal contrast-enhancement (2/26), restricted diffusion (9/19). Location of abnormality was cortical/subcortical, basal ganglia, white matter, corpus callosum, cerebellum. Hippocampus was involved in 10/26 patients. Reversibility of MRI changes was complete in 15, and with residual gliosis or focal atrophy in 11 patients. Reversibility was noted between 15 and 150 days (average, 62 days). Partial simple and complex seizures were associated with hippocampal involvement (p = 0.015), status epilepticus with incomplete reversibility of MRI abnormalities (p = 0.041). Conclusions Seizure or epileptic status can induce transient, variably reversible MRI brain abnormalities. Partial seizures are frequently associated with hippocampal involvement and status epilepticus with incompletely reversible lesions. These seizure-induced MRI abnormalities pose a broad differential diagnosis; increased awareness may reduce the risk of misdiagnosis and unnecessary intervention.

  14. Megarectumsigma underwent surgery for chronic faecal impact action

    International Nuclear Information System (INIS)

    Canessa, C.; Gomez del Valle, M.; Caraballo, M.

    2002-01-01

    Seven patients with megarectumsigma underwent surgery for chronic faecal impaction,reviewing clinical diagnosis, aetiology and medical and surgical management.It is suggested medical management of chronic faecal impaction trying to achieve elective surgery.The curative surgery should include the resection of all pathologic bowel, but in Duhamel procedure and its modifications distal rectal tran section should be at the peritoneal reflection.Habr-Gama modification has shown to be technically easier and it has been communicated good functional results.Local unfavourable conditions may be resolve by staged surgery,which allows outline definitive bowel reconstruction after functional assessment

  15. Posterior reversible encephalopathy syndrome: diagnosis with CT and MRI

    International Nuclear Information System (INIS)

    Wang Guangbin; Zhao Bin; Yang Zhenzhen; Shi Hao; Chiu, L.C.; Shan Ruiqin

    2006-01-01

    Objective: To evaluate the role of CT and MRI in the diagnosis of posterior reversible encephalopathy syndrome (PRES). Methods: Eight women with PRES (6 pregnant women, 1 case after chemotherapy, and 1 patient with hypertension)were enrolled in our study. All of them had MR imaging (T 1 WI, T 2 WI, FLAIR, DWI), and five cases underwent post-contrast T 1 WI and three dimensional contrast enhanced MR angiography (3D CEMRA). Two cases also had CT scan. Results: MRV in all 8 patients showed no evidence of stenosis, dilation, or thrombosis in cranial veins and sinuses. MRI demonstrated multiple lesions located in bilateral parieto-occipital lobes (8 cases), bilateral basal ganglia (2 cases), and bilateral frontal lobes (4 cases). The lesions were prominent within white matter, some of them involved gray matter (3 cases). Lesions appeared as hyperintense signals on FLAIR and T 2 -weighted images, isointense or mildly hypointense signals on T 1 -weighted images, normal or decreased intensity on DWI, and isointensity or hyperintensity on apparent diffusion coefficient (ADC) maps. Post-contrast T 1 WI showed mild reversible enhancement and 3D CEMRA displayed numerous reversible 'grape-like' enhancements in terminal arterial branches along the middle cerebral artery (MCA), anterior cerebral artery (ACA) and posterior cerebral artery (PCA). Follow-up scan showed decreased abnormal signals. Conclusion: Lesions of PRES are usually located in parieto-occipital lobes, especially in white matter, but they can also be seen in frontal lobes and basal ganglia bilaterally. Post-contrast T 1 WI and 3D enhanced MRA can provide useful information in the manifestation of reversible enhancement. MRI has advantages to display lesion in PRES. (authors)

  16. Metal-Free α-C(sp3–H Functionalized Oxidative Cyclization of Tertiary N,N-Diaryl Amino Alcohols: Theoretical Approach for Mechanistic Pathway

    Directory of Open Access Journals (Sweden)

    Zakir Ullah

    2017-03-01

    Full Text Available The mechanistic pathway of TEMPO/I2-mediated oxidative cyclization of N,N-diaryl amino alcohols 1 was investigated. Based on direct empirical experiments, three key intermediates (aminium radical cation 3, α-aminoalkyl radical 4, and iminium 5, four types of reactive species (radical TEMPO, cationic TEMPO, TEMPO-I, and iodo radical, and three types of pathways ((1 SET/PCET mechanism; (2 HAT/1,6-H transfer mechanism; (3 ionic mechanism were assumed. Under the assumption, nine free energy diagrams were acquired through density functional theory calculations. From the comparison of solution-phase free energy, some possible mechanisms were excluded, and then the chosen plausible mechanisms were concretized using the more stable intermediate 7.

  17. Stereoselective Synthesis of Functionalized 1,3-Disubstituted Isoindolines via Rh(III)-Catalyzed Tandem Oxidative Olefination-Cyclization of 4-Aryl-cyclic Sulfamidate-5-Carboxylates.

    Science.gov (United States)

    Achary, Raghavendra; Jung, In-A; Son, Se-Mi; Lee, Hyeon-Kyu

    2017-07-21

    A new method for the direct, stereoselective synthesis of highly functionalized 1,3-disubstituted isoindolines 6 from enantiomerically enriched cyclic 4-aryl-sulfamidate-5-carboxylates (5) is described. The process involves sulfamidate directed, Rh(III)-catalyzed tandem ortho C-H olefination of the 4-aryl-sulfamidate-5-carboxylates and subsequent cyclization by aza-Michael addition. In the reaction, which generates trans-1,3-disubstituted isoindolines exclusively, the configurational integrity of the stereogenic center in the starting cyclic sulfamidate is completely retained in the product. Examples are provided which show that the cyclic sulfamidate moiety not only serves as a chiral directing group but also as a versatile handle for further functionalization of the generated isoindoline ring system.

  18. Cushing’s Disease Presented by Reversible Dilated Cardiomyopathy

    Directory of Open Access Journals (Sweden)

    Berna İmge Aydoğan

    2015-01-01

    Full Text Available Introduction. Dilated cardiomyopathy is rarely reported among CS patients especially without hypertension and left ventricular hypertrophy. Materials and Methods. We hereby report a Cushing’s syndrome case presenting with dilated cardiomyopathy. Results. A 48-year-old female patient was admitted to our clinic with severe proximal myopathy and dilated cardiomyopathy without ventricular hypertrophy. Cushing’s disease was diagnosed and magnetic-resonance imaging of the pituitary gland revealed a microadenoma. Under diuretic and ketoconazole treatments, she underwent a successful transnasal/transsphenoidal adenomectomy procedure. Full recovery of symptoms and echocardiographic features was achieved after six months of surgery. Conclusion. Cushing’s syndrome must be kept in mind as a reversible cause of dilated cardiomyopathy. Recovery of cardiomyopathy is achieved with successful surgery.

  19. Posterior reversible encephalopathy syndrome: An atypical postpartum complication

    Directory of Open Access Journals (Sweden)

    Debashish Paul

    2016-01-01

    Full Text Available Posterior reversible encephalopathy syndrome (PRES is presented by headache, altered mental status, blurring of vision, vomiting and seizure in conjunction with radiological finding of posterior cerebral white matter edema. Data suggest that most cases occur in young middle-aged with marked female preponderance, hypertension being the most common cause. In this case, it was diagnosed in a normotensive patient in the postnatal period that underwent cesarean section. The initial symptoms had misled toward a diagnosis of postdural puncture headache. Symptomatic treatment was started immediately in the ICU. This is an interesting case as the patient was a normotensive one without any other contributory factors and there was unanticipated delay in diagnosing the case until the time we could get a magnetic resonance imaging report.

  20. A cyclized peptide derived from alpha fetoprotein inhibits the proliferation of ER-positive canine mammary cancer cells.

    Science.gov (United States)

    Torres, Cristian Gabriel; Pino, Ana María; Sierralta, Walter Daniel

    2009-06-01

    The effects of estradiol (E2) and of an AFP-derived cyclized peptide (cP) on the proliferation of primary cultures of cancer cells isolated from spontaneous canine mammary tumors were studied. The cellular response to E2 and cP was related to the expression of estradiol receptor (isoforms alpha and beta). In ER-positive cells, 2 nM estradiol increased cell proliferation and the phosphorylation of ERK1/2; 2 microg/ml cP inhibited all these effects. Estradiol also increased HER2 immunoreactivity in ER-positive cells, an effect that was reverted to its basal values by cP. Estradiol stimulated in these cells the release of MMP2 and MMP9 and the shedding of HB-EGF, effects that the cP did not affect. ER-negative cells were refractory to estradiol or cP. All canine mammary tumor cells in culture responded to treatments analogously to human mammary cancer cells. Our results support the proposal of cP as a new, potentially effective therapeutic agent for the management of mammary cancer.

  1. Acute myocardial infarctation in patients with critical ischemia underwent lower limb revascularization

    Directory of Open Access Journals (Sweden)

    Esdras Marques Lins

    2013-12-01

    Full Text Available BACKGROUND: Atherosclerosis is the main cause of peripheral artery occlusive disease (PAOD of the lower limbs. Patients with PAOD often also have obstructive atherosclerosis in other arterial sites, mainly the coronary arteries. This means that patients who undergo infrainguinal bypass to treat critical ischemia have a higher risk of AMI. There are, however, few reports in the literature that have assessed this risk properly. OBJECTIVE: The aim of this study was to determine the incidence of acute myocardial infarction in patients who underwent infrainguinal bypass to treat critical ischemia of the lower limbs caused by PAOD. MATERIAL AND METHODS: A total of 64 patients who underwent 82 infrainguinal bypass operations, from February 2011 to July 2012 were studied. All patients had electrocardiograms and troponin I blood assays during the postoperative period (within 72 hours. RESULTS: There were abnormal ECG findings and elevated blood troponin I levels suggestive of AMI in five (6% of the 82 operations performed. All five had conventional surgery. The incidence of AMI as a proportion of the 52 conventional surgery cases was 9.6%. Two patients died. CONCLUSION: There was a 6% AMI incidence among patients who underwent infrainguinal bypass due to PAOD. Considering only cases operated using conventional surgery, the incidence of AMI was 9.6%.

  2. The significance of reverse flow in ductus venosus between sixteen and twenty weeks’ gestation

    Directory of Open Access Journals (Sweden)

    Gökhan Karakoç

    2017-03-01

    Full Text Available Objective: To evaluate the correlation between reversed a-wave in ductus venosus at 16-20 weeks’ gestation and trisomy 21 and adverse perinatal outcomes. Materials and Methods: Our study included 174 pregnant women who were under follow-up at a tertiary center between May and September 2010. Ductus venosus Doppler (DVD measurements were obtained throughout the 6-month period from women who underwent amniocentesis procedures due to increased risk for trisomy 21 in terms of first or second trimester screening test results. These women were followed up for enrollment of subsequent data about perinatal outcomes. Results: In 13 of 174 cases, Doppler studies indicated a reversed a-wave in the ductus venosus. Of these fetuses, 3 were diagnosed as having trisomy 21 after amniocentesis, which related to 60% (3 of 5 fetuses of all fetuses with trisomy 21. The pregnant women with reversed a-wave in DVD also had an increased rate of preeclampsia (15% and gestational diabetes mellitus (GDM (23% in late pregnancy. Conclusion: Reversed a-wave in ductus venosus between 16-20 weeks’ gestation is associated with increased risk of trisomy 21, preeclampsia, and GDM. If further prospective studies confirm its utility, DVD interrogation for trisomy 21 may be extended until 20 weeks’ gestation.

  3. Reversible Thermoset Adhesives

    Science.gov (United States)

    Mac Murray, Benjamin C. (Inventor); Tong, Tat H. (Inventor); Hreha, Richard D. (Inventor)

    2016-01-01

    Embodiments of a reversible thermoset adhesive formed by incorporating thermally-reversible cross-linking units and a method for making the reversible thermoset adhesive are provided. One approach to formulating reversible thermoset adhesives includes incorporating dienes, such as furans, and dienophiles, such as maleimides, into a polymer network as reversible covalent cross-links using Diels Alder cross-link formation between the diene and dienophile. The chemical components may be selected based on their compatibility with adhesive chemistry as well as their ability to undergo controlled, reversible cross-linking chemistry.

  4. Zero field reversal probability in thermally assisted magnetization reversal

    Science.gov (United States)

    Prasetya, E. B.; Utari; Purnama, B.

    2017-11-01

    This paper discussed about zero field reversal probability in thermally assisted magnetization reversal (TAMR). Appearance of reversal probability in zero field investigated through micromagnetic simulation by solving stochastic Landau-Lifshitz-Gibert (LLG). The perpendicularly anisotropy magnetic dot of 50×50×20 nm3 is considered as single cell magnetic storage of magnetic random acces memory (MRAM). Thermally assisted magnetization reversal was performed by cooling writing process from near/almost Curie point to room temperature on 20 times runs for different randomly magnetized state. The results show that the probability reversal under zero magnetic field decreased with the increase of the energy barrier. The zero-field probability switching of 55% attained for energy barrier of 60 k B T and the reversal probability become zero noted at energy barrier of 2348 k B T. The higest zero-field switching probability of 55% attained for energy barrier of 60 k B T which corespond to magnetif field of 150 Oe for switching.

  5. The 5-Endo-trig Cyclization of D-Glucose Derived γ-Alkenylamines with Mercury (II Salts: Synthesis of 1-Deoxycastanospermine and its 8a-epi-Analogueâ€

    Directory of Open Access Journals (Sweden)

    S. Jachak

    2005-08-01

    Full Text Available The intramolecular aminomercuration of γ-alkenylamines 1a, 1b and 4 was shown to afford the 5-endo-trig cyclized product exclusively in good yield. The utility of pyrrolidine derivatives thus obtained from D-glucose derived γ-alkenylamines 1a and 1b was demonstrated in the synthesis of 1-deoxycastanospermine (3a and 1-deoxy-8a-epi- castanospermine (3b.

  6. Reverse Osmosis

    Indian Academy of Sciences (India)

    many applications, one of which is desalination of seawater. The inaugural Nobel Prize in Chemistry was awarded in 1901 to van 't Hoff for his seminal work in this area. The present article explains the principle of osmosis and reverse osmosis. Osmosis and Reverse Osmosis. As the name suggests, reverse osmosis is the ...

  7. Study on the synthesis of the cyclopenta[f]indole core of raputindole A

    Directory of Open Access Journals (Sweden)

    Nils Marsch

    2016-02-01

    Full Text Available The raputindoles from the rutaceous tree Raputia simulans share a cyclopenta[f]indole partial structure the synthesis of which is subject of this investigation. An efficient route to a series of 1,5-di(indol-6-ylpentenones was developed via Mo/Au-catalyzed Meyer–Schuster rearrangement of tertiary propargylic alcohol precursors. However, none of the enones underwent the desired Nazarov cyclization to a cyclopenta[f]indole. More suitable were 6-hydroxyallylated indolines which gave good yields of cyclopenta[f]indolines after treatment with SnCl4, as soon as sterically demanding β-cyclocitral adducts were reacted. Most successful were Pt(II and Au(I-catalyzed cyclizations of N-TIPS-protected indolin-6-yl-substituted propargylacetates which provided the hydrogenated tricyclic cyclopenta[f]indole core system in high yield.

  8. Myocardial perfusion assessment at rest and after dipyridamole: MR signal intensity characteristics of reversible and persistent hypoperfusion

    International Nuclear Information System (INIS)

    Wintersperger, B.J.; Penzkofer, H.V.; Huber, A.; Meininger, M.; Scheidler, J.; Reiser, M.; Knez, A.; Haberl, R.; Kerner, M.; Knesewitsch, P.

    2000-01-01

    Methods: Sixteen patients with CAD underwent MR myocardial perfusion assessment at rest and after dipyridamole-induced hyperemia. Qualitative parameters (SI increase, SI upslope) of the SI time-curves were evaluated and characteristics of normal, reversible and persistent hypoperfused myocardium as assessed by 99m TC-SestaMIBI SPECT were compared. Results: Compared with the rest values, normal myocardium showed a significant increase of the SI upslope during hyperemia (P [de

  9. Reverse peroneal artery flap for large defects of ankle and foot: A reliable reconstructive technique

    Directory of Open Access Journals (Sweden)

    Jose Tharayil

    2012-01-01

    Full Text Available Background: Large soft tissue defects around the lower third of the leg, ankle and foot always have been challenging to reconstruct. Reverse sural flaps have been used for this problem with variable success. Free tissue transfer has revolutionised management of these problem wounds in selected cases. Materials and Methods: Twenty-two patients with large defects around the lower third of the leg, ankle and foot underwent reconstruction with reverse peroneal artery flap (RPAF over a period of 7 years. The mean age of these patients was 41.2 years. Results: Of the 22 flaps, 21 showed complete survival without even marginal necrosis. One flap failed, where atherosclerotic occlusion of peroneal artery was evident on the table. Few patients had minor donor site problems that settled with conservative management. Conclusions: RPAF is a very reliable flap for the coverage of large soft tissue defects of the heel, sole and dorsum of foot. This flap adds versatility in planning and execution of this extended reverse sural flap.

  10. Reverse waffle cone technique in management of stent dislodgement into intracranial aneurysms.

    Science.gov (United States)

    Luo, Chao-Bao; Lai, Yen-Jun; Teng, Michael Mu-Huo; Chang, Feng-Chi; Lin, Chung-Jung; Guo, Wan-Yuo

    2013-09-01

    Stent-assisted coil embolization (SACE) is a common method to manage intracranial wide-neck aneurysm. Using this technique, a stent must be successfully deployed into the parent artery to cross the aneurysm neck. We describe the reverse waffle cone technique in management of intra-procedural stent dislodgement during SACE of internal carotid artery (ICA) wide-neck aneurysms. Two patients with unruptured wide-neck ICA aneurysms underwent SACE. Intra-procedural forward stent migration occurred during catheterization with proximal stent dislodgement and migration into the aneurysm sac. Navigation of a second stent to bridge the aneurysm neck failed in one patient because the second stent was impeded by the dislodged stent. Using the reverse waffle cone technique, a microcatheter was navigated into the aneurysm sacs. Coils were safely detached into each aneurysm sac without any device assistance. The two wide-neck aneurysms were successfully treated with preservation of flow to the internal carotid arteries. The complication of intra-procedural distal stent migration and dislodgement, with proximal stent prolapse into an aneurysm sac, may not result in a failure to coil the aneurysm. The reverse waffle cone technique provides an effective treatment in the management of this complication. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Determinants of Reverse Remodeling of the Left Atrium Following Transaortic Myectomy.

    Science.gov (United States)

    Nguyen, Anita; Schaff, Hartzell V; Nishimura, Rick A; Dearani, Joseph A; Geske, Jeffrey B; Lahr, Brian D; Ommen, Steve R

    2018-04-18

    In patients with hypertrophic cardiomyopathy (HCM), enlargement of the left atrium (LA) is associated with increased morbidity and mortality due to risk of atrial fibrillation (AF), stroke, and heart failure. In this study, we investigated whether LA reverse remodeling occurs following septal myectomy. Between March 2007 and July 2015, 656 patients underwent myectomy at our institution and had pre- and postoperative transthoracic echocardiographic (TTE) recording of LA volume index (LAVI). We reviewed clinical and echocardiographic data of these patients, and assessed for changes over time by comparing pre- and postoperative measurements. The median age was 56 (46, 65) years, and 370 (56%) were male. New York Heart Association Class III/IV dyspnea was present in 581 (89%). Preoperative TTE showed LAVI of 48 (38, 60) mL/m 2 . In patients with history of AF, preoperative LAVI was 57 (45, 68) mL/m 2 , and in those without AF, LAVI measured 45 (37, 57) mL/m 2 (p < 0.001). All patients underwent transaortic septal myectomy. Early postoperative TTE (4 [3, 5] days) demonstrated LAVI of 43 (36, 52) mL/m 2 (p < 0.001), and late postoperative TTE (2.0 [1.1, 4.1] years) showed LAVI of 38 (29, 47) mL/m 2 (p < 0.001). Preoperative LAVI was associated with late development of AF (p = 0.002). Left atrial volume decreases significantly following surgical relief of left ventricular outflow tract obstruction. Early changes likely reflect lower LA pressure due to gradient relief and abolishment of mitral regurgitation, and late reduction suggests continued reverse remodeling. Copyright © 2018. Published by Elsevier Inc.

  12. The impact of surgeon volume on colostomy reversal outcomes after Hartmann's procedure for diverticulitis.

    Science.gov (United States)

    Aquina, Christopher T; Probst, Christian P; Becerra, Adan Z; Hensley, Bradley J; Iannuzzi, James C; Noyes, Katia; Monson, John R T; Fleming, Fergal J

    2016-11-01

    Colostomy reversal after Hartmann's procedure for diverticulitis is a morbid procedure, and studies investigating factors associated with outcomes are lacking. This study identifies patient, surgeon, and hospital-level factors associated with perioperative outcomes after stoma reversal. The Statewide Planning and Research Cooperative System was queried for urgent/emergency Hartmann's procedures for diverticulitis between 2000-2012 in New York State and subsequent colostomy reversal within 1 year of the procedure. Surgeon and hospital volume were categorized into tertiles based on the annual number of colorectal resections performed each year. Bivariate and mixed-effects analyses were used to assess the association between patient, surgeon, and hospital-level factors and perioperative outcomes after colostomy reversal, including a laparoscopic approach; duration of stay; intensive care unit admission; complications; mortality; and 30-day, unscheduled readmission. Among 10,487 patients who underwent Hartmann's procedure and survived to discharge, 63% had the colostomy reversed within 1 year. After controlling for patient, surgeon, and hospital-level factors, high-volume surgeons (≥40 colorectal resections/yr) were independently associated with higher odds of a laparoscopic approach (unadjusted rates: 14% vs 7.6%; adjusted odds ratio = 1.84, 95% confidence interval = 1.12, 3.00), shorter duration of stay (median: 6 versus 7 days; adjusted incidence rate ratio = 0.87, 95% confidence interval = 0.81, 0.95), and lower odds of 90-day mortality (unadjusted rates: 0.4% vs 1.0%; adjusted odds ratio = 0.30, 95% confidence interval = 0.10, 0.88) compared with low-volume surgeons (1-15 colorectal resections/yr). High-volume surgeons are associated with better perioperative outcomes and lower health care utilization after Hartmann's reversal for diverticulitis. These findings support referral to high-volume surgeons for colostomy reversal. Copyright © 2016

  13. Managing Reverse Logistics or Reversing Logistics Management?

    NARCIS (Netherlands)

    M.P. de Brito (Marisa)

    2004-01-01

    textabstractIn the past, supply chains were busy fine-tuning the logistics from raw material to the end customer. Today an increasing flow of products is going back in the chain. Thus, companies have to manage reverse logistics as well.This thesis contributes to a better understanding of reverse

  14. Relationship Between Reverse Remodeling and Cardiopulmonary Exercise Capacity in Heart Failure Patients Undergoing Cardiac Resynchronization Therapy

    DEFF Research Database (Denmark)

    Mastenbroek, Mirjam H; Sant, Jetske Van't; Versteeg, Henneke

    2016-01-01

    -defibrillator (mean age 65 ± 11; 73% male) underwent echocardiography and cardiopulmonary exercise testing (CPX) before implantation (baseline) and 6 months after implantation. At baseline, patients also completed a set of questionnaires measuring mental and physical health. The association between echocardiographic...... echocardiographic responders showed improvements in ventilatory efficiency during follow-up. Multivariable repeated measures analyses revealed that, besides reverse remodeling, New York Heart Association functional class II and good patient-reported health status before implantation were the most important...

  15. Effect of using pump on postoperative pleural effusion in the patients that underwent CABG

    Directory of Open Access Journals (Sweden)

    Mehmet Özülkü

    2015-08-01

    Full Text Available Abstract Objective: The present study investigated effect of using pump on postoperative pleural effusion in patients who underwent coronary artery bypass grafting. Methods: A total of 256 patients who underwent isolated coronary artery bypass grafting surgery in the Cardiovascular Surgery clinic were enrolled in the study. Jostra-Cobe (Model 043213 105, VLC 865, Sweden heart-lung machine was used in on-pump coronary artery bypass grafting. Off-pump coronary artery bypass grafting was performed using Octopus and Starfish. Proximal anastomoses to the aorta in both on-pump and off-pump techniques were performed by side clamps. The patients were discharged from the hospital between postoperative day 6 and day 11. Results: The incidence of postoperative right pleural effusion and bilateral pleural effusion was found to be higher as a count in Group 1 (on-pump as compared to Group 2 (off-pump. But the difference was not statistically significant [P>0.05 for right pleural effusion (P=0.893, P>0.05 for bilateral pleural effusion (P=0.780]. Left pleural effusion was encountered to be lower in Group 2 (off-pump. The difference was found to be statistically significant (P<0.05, P=0.006. Conclusion: Under the light of these results, it can be said that left pleural effusion is less prevalent in the patients that underwent off-pump coronary artery bypass grafting when compared to the patients that underwent on-pump coronary artery bypass grafting.

  16. Gold-Catalyzed Cyclization of Furan-Ynes bearing a Propargyl Carbonate Group: Intramolecular Diels-Alder Reaction with In Situ Generated Allenes.

    Science.gov (United States)

    Sun, Ning; Xie, Xin; Chen, Haoyi; Liu, Yuanhong

    2016-09-26

    Gold-catalyzed cyclization of various furan-ynes with a propargyl carbonate or ester moiety results in the formation of a series of polycyclic aromatic ring systems. The reactions can be rationalized through a tandem gold-catalyzed 3,3-rearrangement of the propargyl carboxylate moiety in furan-yne substrates to form an allenic intermediate, which is followed by an intramolecular Diels-Alder reaction of furan and subsequent ring-opening of the oxa-bridged cycloadduct. It was found that the steric and electronic properties of phosphine ligands on the gold catalyst had a significant impact on the reaction outcome. In the case of 1,5-furan-yne, the cleavage of the oxa-bridge in the cycloadduct with concomitant 1,2-migration of the R(1) group occurs to furnish anthracen-1(2H)-ones bearing a quaternary carbon center. For 1,4-furan-yne, a facile aromatization of the cycloadduct takes place to give 9-oxygenated anthracene derivatives. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Two weeks taurine supplementation reverses endothelial dysfunction in young male type 1 diabetics.

    LENUS (Irish Health Repository)

    Moloney, Michael A

    2010-10-01

    Type 1 diabetics have a well-recognised risk of accelerated cardiovascular disease. Even in the absence of clinical signs there are detectable abnormalities of conduit vessel function. Our group has previously reported reversal of endothelial dysfunction in diabetics with pravastatin. In young asymptomatic smokers, taurine supplementation has a beneficial impact on macrovascular function, assessed by FMD, and shows an up-regulation of nitric oxide from monocyte-endothelial cell interactions. We hypothesise that taurine supplementation reverses early endothelial abnormalities in young male type 1 diabetics, as assessed by applanation tonometry, brachial artery ultrasound and laser Doppler fluximetry. Asymptomatic, male diabetics (n=9) were scanned prior to treatment and then randomised in a double-blind cross-over fashion to receive either 2 weeks placebo or taurine. Control patients (n=10) underwent a baseline scan. Assessed diabetics had detectable, statistically significant abnormalities when compared with controls, in both arterial stiffness (augmentation index) and brachial artery reactivity (FMD). Both of these parameters were returned to control levels with 2 weeks taurine supplementation. In conclusion, 2 weeks taurine supplementation reverses early, detectable conduit vessel abnormalities in young male diabetics. This may have important implications in the long-term treatment of diabetic patients and their subsequent progression towards atherosclerotic disease.

  18. Reverse genetics with animal viruses. NSV reverse genetics

    International Nuclear Information System (INIS)

    Mebatsion, T.

    2005-01-01

    New strategies to genetically manipulate the genomes of several important animal pathogens have been established in recent years. This article focuses on the reverse genetics techniques, which enables genetic manipulation of the genomes of non-segmented negative-sense RNA viruses. Recovery of a negative-sense RNA virus entirely from cDNA was first achieved for rabies virus in 1994. Since then, reverse genetic systems have been established for several pathogens of medical and veterinary importance. Based on the reverse genetics technique, it is now possible to design safe and more effective live attenuated vaccines against important viral agents. In addition, genetically tagged recombinant viruses can be designed to facilitate serological differentiation of vaccinated animals from infected animals. The approach of delivering protective immunogens of different pathogens using a single vector was made possible with the introduction of the reverse genetics system, and these novel broad-spectrum vaccine vectors have potential applications in improving animal health in developing countries. (author)

  19. Outcome of Patients Underwent Emergency Department Thoracotomy and Its Predictive Factors

    Directory of Open Access Journals (Sweden)

    Shahram Paydar

    2014-08-01

    Full Text Available Introduction: Emergency department thoracotomy (EDT may serve as the last survival chance for patients who arrive at hospital in extremis. It is considered as an effective tool for improvement of traumatic patients’ outcome. The present study was done with the goal of assessing the outcome of patients who underwent EDT and its predictive factors. Methods: In the present study, medical charts of 50 retrospective and 8 prospective cases underwent emergency department thoracotomy (EDT were reviewed during November 2011 to June 2013. Comparisons between survived and died patients were performed by Mann-Whitney U test and the predictive factors of EDT outcome were measured using multivariate logistic regression analysis. P < 0.05 considered statistically significant. Results: Fifty eight cases of EDT were enrolled (86.2% male. The mean age of patients was 43.27±19.85 years with the range of 18-85. The mean time duration of CPR was recorded as 37.12±12.49 minutes. Eleven cases (19% were alive to be transported to OR (defined as ED survived. The mean time of survival in ED survived patients was 223.5±450.8 hours. More than 24 hours survival rate (late survived was 6.9% (4 cases. Only one case (1.7% survived to discharge from hospital (mortality rate=98.3%. There were only a significant relation between ED survival and SBP, GCS, CPR duration, and chest trauma (p=0.04. The results demonstrated that initial SBP lower than 80 mmHg (OR=1.03, 95% CI: 1.001-1.05, p=0.04 and presence of chest trauma (OR=2.6, 95% CI: 1.75-3.16, p=0.02 were independent predictive factors of EDT mortality. Conclusion: The findings of the present study showed that the survival rate of trauma patients underwent EDT was 1.7%. In addition, it was defined that falling systolic blood pressure below 80 mmHg and blunt trauma of chest are independent factors that along with poor outcome.

  20. Incidence of Bradycardia and Outcomes of Patients Who Underwent Orbital Atherectomy Without a Temporary Pacemaker.

    Science.gov (United States)

    Lee, Michael S; Nguyen, Heajung; Shlofmitz, Richard

    2017-02-01

    We analyzed the incidence of bradycardia and the safety of patients with severely calcified coronary lesions who underwent orbital atherectomy without the insertion of a temporary pacemaker. The presence of severely calcified coronary lesions can increase the complexity of percutaneous coronary intervention due to the difficulty in advancing and optimally expanding the stent. High-pressure inflations to predilate calcified lesions may cause angiographic complications like perforation and dissection. Suboptimal stent expansion is associated with stent thrombosis and restenosis. Orbital atherectomy safely and effectively modifies calcified plaque to facilitate optimal stent expansion. The incidence of bradycardia in orbital atherectomy is unknown. Fifty consecutive patients underwent orbital atherectomy from February 2014 to September 2016 at our institution, none of whom underwent insertion of a temporary pacemaker. The final analysis included 47 patients in this retrospective study as 3 patients were excluded because of permanent pacemaker implantation. The primary endpoint was significant bradycardia, defined as bradycardia requiring emergent pacemaker placement or a heart rate pacemaker appears to be safe.

  1. A computational mechanistic study of Pd(ii)-catalyzed γ-C(sp3)-H olefination/cyclization of amines: the roles of bicarbonate and ligand effect.

    Science.gov (United States)

    Liu, Jian-Biao; Tian, Ying-Ying; Zhang, Xin; Wang, Lu-Lin; Chen, De-Zhan

    2018-04-03

    The detailed mechanism of palladium-catalyzed γ-C(sp3)-H olefination/cyclization of triflyl-protected amines was investigated by density functional theory (DFT) calculations. The olefinated intermediate was initially formed in the first catalytic cycle involving ligand exchange, bicarbonate-assisted C(sp3)-H bond cleavage, alkene insertion and 'reductive β-hydride elimination'. The following syn-addition and reductive elimination furnish the aza-Wacker product. The first step of reductive elimination is the rate-determining step. The mechanism unveils the important roles of bicarbonate: aiding the C-H activation and abstracting the β-proton in the second step of reductive elimination. The parallel bridging mode in the metal-olefin intermediate facilitates the syn-addition, explaining the experimentally observed stereoselectivity. The effect of the monodentate pyridine-based ligands is also discussed.

  2. Amine-selective bioconjugation using arene diazonium salts.

    Science.gov (United States)

    Diethelm, Stefan; Schafroth, Michael A; Carreira, Erick M

    2014-08-01

    A novel bioconjugation strategy is presented that relies on the coupling of diazonium terephthalates with amines in proteins. The diazonium captures the amine while the vicinal ester locks it through cyclization, ensuring no reversibility. The reaction is highly efficient and proceeds under mild conditions and short reaction times. Densely functionalized, complex natural products were directly coupled to proteins using low concentrations of coupling partners.

  3. An Efficient Solid-phase Parallel Synthesis of 2-Amino and 2-Amidobenzo[d]oxazole Derivatives via Cyclization Reactions of 2-Hydroxyphenylthiourea Resin

    International Nuclear Information System (INIS)

    Jung, Selin; Kim, Seulgi; Lee, Geehyung; Gong, Youngdae

    2012-01-01

    An efficient solid-phase methodology has been developed for the synthesis of 2-amino and 2-amidobenzo[d]-oxazole derivatives. The key step in this procedure involves the preparation of polymer-bound 2-aminobenzo-[d]oxazole resins 4 by cyclization reaction of 2-hydroxyphenylthiourea resin 3. The resin-bound 2-hydroxy-phenylthiourea 3 is produced by the addition of 2-aminophenol to the isothiocyanate-terminated resin 2 and serve as a key intermediate for the linker resin. This core skeleton 2-aminobenzo[d]oxazole resin 4 undergoes functionalization reaction with various electrophiles, such as alkylhalides and acid chlorides to generate 2-amino and 2-amidobenzo[d]oxazole resins 5 and 6 respectively. Finally, 2-amino and 2-amidobenzo[d]oxazole derivatives 7 and 8 are then generated in good yields and purities by cleavage of the respective resins 5 and 6 under trifluoroacetic acid (TFA) in dichloromethane (CH 2 Cl 2 )

  4. A controlled-release mitochondrial protonophore reverses hypertriglyceridemia, nonalcoholic steatohepatitis, and diabetes in lipodystrophic mice.

    Science.gov (United States)

    Abulizi, Abudukadier; Perry, Rachel J; Camporez, João Paulo G; Jurczak, Michael J; Petersen, Kitt Falk; Aspichueta, Patricia; Shulman, Gerald I

    2017-07-01

    Lipodystrophy is a rare disorder characterized by complete or partial loss of adipose tissue. Patients with lipodystrophy exhibit hypertriglyceridemia, severe insulin resistance, type 2 diabetes, and nonalcoholic steatohepatitis (NASH). Efforts to ameliorate NASH in lipodystrophies with pharmacologic agents have met with limited success. We examined whether a controlled-release mitochondrial protonophore (CRMP) that produces mild liver-targeted mitochondrial uncoupling could decrease hypertriglyceridemia and reverse NASH and diabetes in a mouse model (fatless AZIP/F-1 mice) of severe lipodystrophy and diabetes. After 4 wk of oral CRMP (2 mg/kg body weight per day) or vehicle treatment, mice underwent hyperinsulinemic-euglycemic clamps combined with radiolabeled glucose to assess liver and muscle insulin responsiveness and tissue lipid measurements. CRMP treatment reversed hypertriglyceridemia and insulin resistance in liver and skeletal muscle. Reversal of insulin resistance could be attributed to reductions in diacylglycerol content and reduced PKC-ε and PKC-θ activity in liver and muscle respectively. CRMP treatment also reversed NASH as reflected by reductions in plasma aspartate aminotransferase and alanine aminotransferase concentrations; hepatic steatosis; and hepatic expression of IL-1α, -β, -2, -4, -6, -10, -12, CD69, and caspase 3 and attenuated activation of the IRE-1α branch of the unfolded protein response. Taken together, these results provide proof of concept for the development of liver-targeted mitochondrial uncoupling agents as a potential novel therapy for lipodystrophy-associated hypertriglyceridemia, NASH and diabetes.-Abulizi, A., Perry, R. J., Camporez, J. P. G., Jurczak, M. J., Petersen, K. F., Aspichueta, P., Shulman, G. I. A controlled-release mitochondrial protonophore reverses hypertriglyceridemia, nonalcoholic steatohepatitis, and diabetes in lipodystrophic mice. © FASEB.

  5. Water soluble contrast enema examination of the integrity of the rectal anastomosis prior to loop ileostomy reversal may be superfluous.

    Science.gov (United States)

    Larsson, Anna; Lindmark, Gudrun; Syk, Ingvar; Buchwald, Pamela

    2015-03-01

    Defunctioning loop ileostomy in low anterior resection (LAR) is routinely used to reduce consequences of anastomotic leakage. The purpose of this study was to analyze which examination technique is optimal for evaluating the integrity of the anastomosis prior to loop ileostomy reversal. Retrospective analysis of 95 patients who had been subjected to LAR at Helsingborg Hospital and Skåne University Hospital, Sweden, was undertaken between January 2007 and June 2009. The examination techniques of the rectal anastomosis prior to reversal and the clinical outcome after reversal were studied. Radiologic anastomosis control using water soluble contrast enema, digital rectal examination (DRE), and rectoscopy were performed in 53 % (50/95), 98 % (93/95), and 69 % (66/95), respectively. In two patients, no control of the anastomosis was performed before reversal. Fifty-two percent (49/95) of the patients were examined using all techniques. Six patients demonstrated leakage detected before reversal of which two were only radiological leakages. These two patients underwent loop ileostomy reversal after delay without complications. They were the only ones where the three examination techniques did not prove coherence. Four patients had symptomatic leakage; these were detected with rectoscopy and DRE and verified with enema. Three patients developed anastomotic leakage after loop ileostomy reversal despite normal preoperative examinations. Two of these patients had rectovaginal fistulas (AVFs). This retrospective study indicates that contrast enema does not provide additional information if rectoscopy and DRE are normal. Despite negative examinations, three of nine leakages were diagnosed after loop ileostomy reversal. Especially, AVFs seem difficult to diagnose.

  6. Comparison of Voice Quality Between Patients Who Underwent Inferior Turbinoplasty or Radiofrequency Cauterization.

    Science.gov (United States)

    Göker, Ayşe Enise; Aydoğdu, İmran; Saltürk, Ziya; Berkiten, Güler; Atar, Yavuz; Kumral, Tolgar Lütfi; Uyar, Yavuz

    2017-01-01

    The aim of this study was to analyze and compare the vocal quality in patients who underwent either submucosal turbinectomy or radiofrequency cauterization. In this study, we enrolled 60 patients diagnosed with inferior concha hypertrophy. These patients were divided into two groups by using computer program "Research Randomizer." Of the 60 patients, 30 underwent submucosal inferior turbinoplasty and 30 underwent radiofrequency cauterization. The control group was composed of 30 healthy adults with no nasal or upper aerodigestive system pathology. The patients were checked at weeks 1, 2, and 4. Voice records were taken before the procedure and at week 4 postprocedure. The mean age of patients in the inferior turbinoplasty group was 29.4 years (range: 19-42 years); in the radiofrequency group, it was 30.30 years (range: 18-50 years). There was no statistical difference in age between groups. In the inferior turbinoplasty group, there were 16 male and 14 female patients, and in the radiofrequency group, there were 13 male and 17 female patients. There was no significant difference in the number of males and females between groups. Voice professionals, especially singers, actors, and actresses, should be informed about possible voice changes before undergoing endonasal surgery because these individuals are more sensitive to changes in resonance organs. We believe that voice quality should be regarded as a highly important parameter when measuring the success of endonasal surgery. Copyright © 2017 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

  7. A Case of Heel Reconstruction with a Reverse Sural Artery Flap in a Hemophilia B Patient

    Directory of Open Access Journals (Sweden)

    Byung Kwon Lee

    2012-03-01

    Full Text Available Hemophilia B is a rare blood coagulation disorder. Complications such as bleeding and hematoma can cause necrosis of flaps, wound disruption, and the disturbance of wound healing. In particular, guidelines for flap operations in hemophilia B patients have still not been defined, and case reports are rare. We reconstructed the heel of a 41-year-old male hemophilia B patient using a reverse sural artery flap operation. The patient presented with mild hemophilia, having 27% of the normal value of coagulation factor IX. Coagulation and the changing value of the coagulation factor were regularly measured, and 70% of the normal value of coagulation factor IX was maintained through the injection of recombinant coagulation factors and antihemorrhagics. Hematoma developed twice (postoperative day [POD] 5 and POD 7 and in each case the hematoma was removed. Injections of recombinant coagulation factors and antihemorrhagics were continuously administered until postoperative week 2. When the coagulation factors were within normal ranges. In this article, a hemophilia B patient underwent reverse sural artery flap surgery and the healing progress was analyzed. We conclude that higher than baseline levels of coagulation factors are needed for successful healing in reverse sural artery flap surgery.

  8. An algebra of reversible computation.

    Science.gov (United States)

    Wang, Yong

    2016-01-01

    We design an axiomatization for reversible computation called reversible ACP (RACP). It has four extendible modules: basic reversible processes algebra, algebra of reversible communicating processes, recursion and abstraction. Just like process algebra ACP in classical computing, RACP can be treated as an axiomatization foundation for reversible computation.

  9. On thermodynamic and microscopic reversibility

    International Nuclear Information System (INIS)

    Crooks, Gavin E

    2011-01-01

    The word 'reversible' has two (apparently) distinct applications in statistical thermodynamics. A thermodynamically reversible process indicates an experimental protocol for which the entropy change is zero, whereas the principle of microscopic reversibility asserts that the probability of any trajectory of a system through phase space equals that of the time reversed trajectory. However, these two terms are actually synonymous: a thermodynamically reversible process is microscopically reversible, and vice versa

  10. Reversibility of female sterilization.

    Science.gov (United States)

    Siegler, A M; Hulka, J; Peretz, A

    1985-04-01

    The discussion considers the current status of reversibility of sterilization in the US and describes clinical and experimental efforts for developing techniques designed for reversibility. It focuses on regret following sterilization, reversal potential of current sterilization techniques, patient selection, current reversal techniques, results of sterilization procedures, experimental approaches to reversal of current techniques of sterilization, and sterilization procedures devised for reversibility, in humans and in animals. Request is the 1st stage of reversal, but a request for sterilization reversal (SR) does not always mean regret for a decision made at the time. Frequently it is a wish to restore fertility because life circumstances have changed after a sterilization that was ppropriate at the time it was performed. Schwyhart and Kutner reviewed 22 studies published between 1949-69 in which they found that the percentage of patients regretting the procedure ranged from 1.3-15%. Requests for reversal remain low in most countries, but if sterilization becomes a more popular method of contraception, requests will also increase. The ideal operation considered as a reversaible method of sterilization should include an easy, reliable outpatient method of tubal occlusion with miniml risk or patient discomfort that subsequently could be reversed without the need for a major surgical intervention. Endoscopic methods have progressed toward the 1st objective. A recent search of the literature uncovered few series of SR of more than 50 cases. The 767 operations found were analyzed with regard to pregnancy outcome. The precent of live births varied from 74-78.8%, and the occurance of tubal pregnancies ranged from 1.7-6.5%. All of the confounding variables in patient selection and small numbers of reported procedures preclude any conclusion about the different techniques or the number of operations that give a surgeon a level of expertise. Few authors classify their

  11. [A Distal Bile Duct Carcinoma Patient Who Underwent Surgical Resection for Liver Metastasis].

    Science.gov (United States)

    Komiyama, Sosuke; Izumiya, Yasuhito; Kimura, Yu; Nakashima, Shingo; Kin, Syuichi; Kawakami, Sadao

    2018-03-01

    A 70-year-old man with distal bile duct carcinoma underwent a subtotal stomach-preserving pancreaticoduodenectomy without adjuvant chemotherapy. One and a half years after the surgery, elevated levels of serum SPan-1(38.1 U/mL)were observed and CT scans demonstrated a solitary metastasis, 25mm in size, in segment 8 of the liver. The patient received 2 courses of gemcitabine-cisplatin combination chemotherapy. No new lesions were detected after chemotherapy and the patient underwent a partial liver resection of segment 8. The pathological examination revealed a metachronous distant metastasis originating from the bile duct carcinoma. Subsequently, the patient received S-1 adjuvant chemotherapy for 6 months. Following completion of all therapies, the patient survived without tumor recurrence for 3 years and 10 months after the initial operation. Thus, surgical interventions might be effective in improving prognosis among selected patients with postoperative liver metastasis of bile duct carcinoma.

  12. Effects of the Amino Acid Linkers on the Melanoma-Targeting and Pharmacokinetic Properties of Indium-111-labeled Lactam Bridge-Cyclized α-MSH Peptides

    Science.gov (United States)

    Guo, Haixun; Yang, Jianquan; Gallazzi, Fabio; Miao, Yubin

    2011-01-01

    The purpose of this study was to examine the profound effects of the amino acid linkers on the melanoma targeting and pharmacokinetic properties of novel 111In-labeled lactam bridge-cyclized DOTA-[X]-CycMSHhex {1,4,7,10-Tetraazacyclododecane-1,4,7,10-tetraacetic acid-[X]-c[Asp-His-dPhe-Arg-Trp-Lys]-CONH2, X=GlyGlyNle, GlyGluNle or NleGlyGlu} peptides. Methods Three novel DOTA-GGNle-CycMSHhex, DOTA-GENle-CycMSHhex and DOTA-NleGE-CycMSHhex peptides were designed and synthesized. The melanocortin-1 (MC1) receptor binding affinities of the peptides were determined in B16/F1 melanoma cells. The melanoma targeting and pharmacokinetic properties of 111In-DOTA-GGNle-CycMSHhex and 111In-DOTA-GENle-CycMSHhex were determined in B16/F1 melanoma-bearing C57 mice. Results DOTA-GGNle-CycMSHhex and DOTA-GENle-CycMSHhex displayed 2.1 and 11.5 nM MC1 receptor binding affinities, whereas DOTA-NleGE-CycMSHhex showed 873.4 nM MC1 receptor binding affinity. The introduction of the -GlyGly- linker maintained high melanoma uptake while decreased the renal and liver uptakes of 111In-DOTA-GlyGlyNle-CycMSHhex. The tumor uptake values of 111In-DOTA-GGNle-CycMSHhex were 19.05 ± 5.04 and 18.6 ± 3.56 % injected dose/gram (%ID/g) at 2 and 4 h post-injection. 111In-DOTA-GGNle-CycMSHhex exhibited 28, 32 and 42% less renal uptake values than 111In-DOTA-Nle-CycMSHhex we reported previously, and 61, 65 and 68% less liver uptake values than 111In-DOTA-Nle-CycMSHhex at 2, 4 and 24 h post-injection, respectively. Conclusion The amino acid linkers exhibited the profound effects on the melanoma targeting and pharmacokinetic properties of the 111In-labeled lactam bridge-cyclized α-MSH peptides. Introduction of the -GlyGly- linker maintained high melanoma uptake while reducing the renal and liver uptakes of 111In-DOTA-GlyGlyNle-CycMSHhex, highlighting its potential as an effective imaging probe for melanoma detection, as well as a therapeutic peptide for melanoma treatment when labeled with a therapeutic

  13. ALGORITHM FOR MANAGEMENT OF HYPERTENSIVE PATIENTS UNDERWENT UROLOGY INTERVENTIONS

    Directory of Open Access Journals (Sweden)

    S. S. Davydova

    2013-01-01

    Full Text Available Aim. To study the efficacy of cardiovascular non-invasive complex assessment and pre-operative preparation in hypertensive patients needed in surgical treatment of urology dis- eases.Material and methods. Males (n=883, aged 40 to 80 years were included into the study. The main group consisted of patients that underwent laparotomic nephrectomy (LTN group; n=96 and patients who underwent laparoscopic nephrectomy (LSN group; n=53. Dynamics of ambulatory blood pressure monitoring (ABPM data was analyzed in these groups in the immediate postoperative period. The efficacy of a package of non-invasive methods for cardiovascular system assessment was studied. ABPM was performed after nephrectomy (2-nd and 10-th days after surgery in patients with complaints of vertigo episodes or intense general weakness to correct treatment.Results. In LTN group hypotension episodes or blood pressure (BP elevations were observed in 20 (20.8% and 22 (22.9% patients, respectively, on the 2-nd day after the operation. These complications required antihypertensive treatment correction. Patients with hypotension episodes were significantly older than patients with BP elevation and had significantly lower levels of 24-hour systolic BP, night diastolic BP and minimal night systolic BP. Re-adjustment of antihypertensive treatment on the 10-th postoperative day was required to 2 (10% patients with hypotension episodes and to 1 (4.5% patient with BP elevation. Correction of antihypertensive therapy was required to all patients in LSN group on the day 2, and to 32 (60.4% patients on the 10-th day after the operation. Reduction in the incidence of complications (from 1.2% in 2009 to 0.3% in 2011, p<0.001 was observed during the application of cardiovascular non-invasive complex assessment and preoperative preparation in hypertensive patients.Conclusion. The elaborated management algorithm for patients with concomitant hypertension is recommended to reduce the cardiovascular

  14. ALGORITHM FOR MANAGEMENT OF HYPERTENSIVE PATIENTS UNDERWENT UROLOGY INTERVENTIONS

    Directory of Open Access Journals (Sweden)

    S. S. Davydova

    2015-09-01

    Full Text Available Aim. To study the efficacy of cardiovascular non-invasive complex assessment and pre-operative preparation in hypertensive patients needed in surgical treatment of urology dis- eases.Material and methods. Males (n=883, aged 40 to 80 years were included into the study. The main group consisted of patients that underwent laparotomic nephrectomy (LTN group; n=96 and patients who underwent laparoscopic nephrectomy (LSN group; n=53. Dynamics of ambulatory blood pressure monitoring (ABPM data was analyzed in these groups in the immediate postoperative period. The efficacy of a package of non-invasive methods for cardiovascular system assessment was studied. ABPM was performed after nephrectomy (2-nd and 10-th days after surgery in patients with complaints of vertigo episodes or intense general weakness to correct treatment.Results. In LTN group hypotension episodes or blood pressure (BP elevations were observed in 20 (20.8% and 22 (22.9% patients, respectively, on the 2-nd day after the operation. These complications required antihypertensive treatment correction. Patients with hypotension episodes were significantly older than patients with BP elevation and had significantly lower levels of 24-hour systolic BP, night diastolic BP and minimal night systolic BP. Re-adjustment of antihypertensive treatment on the 10-th postoperative day was required to 2 (10% patients with hypotension episodes and to 1 (4.5% patient with BP elevation. Correction of antihypertensive therapy was required to all patients in LSN group on the day 2, and to 32 (60.4% patients on the 10-th day after the operation. Reduction in the incidence of complications (from 1.2% in 2009 to 0.3% in 2011, p<0.001 was observed during the application of cardiovascular non-invasive complex assessment and preoperative preparation in hypertensive patients.Conclusion. The elaborated management algorithm for patients with concomitant hypertension is recommended to reduce the cardiovascular

  15. Constraining the reversing and non-reversing modes of the geodynamo. New insights from magnetostratigraphy.

    Science.gov (United States)

    Gallet, Y.; Pavlov, V.; Shatsillo, A.; Hulot, G.

    2015-12-01

    Constraining the evolution in the geomagnetic reversal frequency over hundreds of million years is not a trivial matter. Beyond the fact that there are long periods without reversals, known as superchrons, and periods with many reversals, the way the reversal frequency changes through time during reversing periods is still debated. A smooth evolution or a succession of stationary segments have both been suggested to account for the geomagnetic polarity time scale since the Middle-Late Jurassic. Sudden changes from a reversing mode to a non-reversing mode of the geodynamo may also well have happened, the switch between the two modes having then possibly been controlled by the thermal conditions at the core-mantle boundary. There is, nevertheless, a growing set of magnetostratigraphic data, which could help decipher a proper interpretation of the reversal history, in particular in the early Paleozoic and even during the Precambrian. Although yielding a fragmentary record, these data reveal the occurrence of both additional superchrons and periods characterized by extremely high, not to say extraordinary, magnetic reversal frequencies. In this talk, we will present a synthesis of these data, mainly obtained from Siberia, and discuss their implication for the magnetic reversal behavior over the past billion years.

  16. Synthesis of 2-azaspiro[4.4]nonan-1-ones via phosphine-catalysed [3+2]-cycloadditions

    Energy Technology Data Exchange (ETDEWEB)

    Yong, Sarah R.; Williams, Morwenna C.; Pyne, Stephen G.; Ung, Alison T.; Skelton, Brian W.; White, Allan H.; Turner, Peter (UWA); (Wollongong); (Sydney)

    2008-10-03

    The phosphine-catalyzed [3+2]-cycloaddition of the 2-methylene {gamma}-lactams 4 and 5 and the acrylate 6 with the ylides derived from the ethyl ester, the amide or the chiral camphor sultam derivative of 2-butynoic acid (7a-c) give directly, or indirectly after reductive cyclization, spiro-heterocyclic products. The acid 32 underwent Curtius rearrangement and then acid hydrolysis to give two novel spiro-cyclic ketones, 41 and 42.

  17. Tips of the dual-lumen microcatheter-facilitated reverse wire technique in percutaneous coronary interventions for markedly angulated bifurcated lesions.

    Science.gov (United States)

    Nomura, Tetsuya; Kikai, Masakazu; Hori, Yusuke; Yoshioka, Kenichi; Kubota, Hiroshi; Miyawaki, Daisuke; Urata, Ryota; Sugimoto, Takeshi; Keira, Natsuya; Tatsumi, Tetsuya

    2018-04-01

    In practical settings of percutaneous coronary intervention (PCI), we sometimes encounter difficulty in introducing a guidewire (GW) to the markedly angulated side branch (SB), and the reverse wire technique is considered as a last resort to overcome such a situation. We analyzed 12 cases that underwent PCI with dual-lumen microcatheter-facilitated reverse wire technique between January 2013 and July 2016. We retrospectively investigated the lesion's characteristics and the details of the PCI procedures, and discussed tips about the use of this technique. The SB that exhibits both a smaller take-off angle and a larger carina angle is considered to be the most suitable candidate for this technique. The first step of this technique involves the delivery of the reverse wire system to the target bifurcation. However, most cases exhibit significant stenosis proximal to the bifurcation, which often hampers the delivery of the reverse wire system. Because the sharply curved reverse wire system is easier to pass the stenosis as compared to the roundly curved system, we recommend a sharp curve should be adopted for this technique. On the other hand, it is sure that device delivery is much easier on the GW with a round curve as compared to that with a sharp curve. Therefore, it is important to modify the details of this procedure on a case-by-case basis according to the lesion's characteristics.

  18. Embolisation of the Gastroduodenal Artery is Not Necessary in the Presence of Reversed Flow Before Yttrium-90 Radioembolisation

    Energy Technology Data Exchange (ETDEWEB)

    Daghir, Ahmed A., E-mail: ahmeddaghir@doctors.net.uk [Imperial College Healthcare NHS Trust, Department of Radiology (United Kingdom); Gungor, Hatice [Imperial College Healthcare NHS Trust, Department of Oncology (United Kingdom); Haydar, Ali A. [Barts and the London NHS Trust, Department of Radiology (United Kingdom); Wasan, Harpreet S. [Imperial College Healthcare NHS Trust, Department of Oncology (United Kingdom); Tait, Nicholas P. [Imperial College Healthcare NHS Trust, Department of Radiology (United Kingdom)

    2012-08-15

    Introduction: The gastroduodenal artery (GDA) is usually embolised to avoid nontarget dispersal before yttrium-90 (Y{sup 90}) radioembolisation to treat liver metastases. In a minority of patients, there is retrograde flow in the GDA. The purpose of this study was to determine if there is any increased risk from maintaining a patent GDA in patients with reversed flow. Materials and Methods: A retrospective review was performed of all patients undergoing Y{sup 90} radioembolisation at our institution. The incidence of toxicities arising from nontarget radioembolisation by way of the GDA (gastric/duodenal ulceration, gastric/duodenal bleeding, and pancreatitis) and death occurring within 2 months of treatment were compared between the reversed and the antegrade GDA groups. Results: Ninety-two patients underwent preliminary angiography. Reversed GDA flow was found on angiography in 14.1% of cases; the GDA was not embolised in these patients. The GDA was coiled in 55.7% of patients with antegrade GDA flow to prevent inadvertent dispersal of radioembolic material. There was no increased toxicity related to nontarget dispersal by way of the GDA, or increased early mortality, in patients with reversed GDA flow (P > 0.05). Conclusion: In patients with reversed GDA flow, maintenance of a patent GDA before administration of Y{sup 90} radioembolisation does not increase the risk of toxicity from nontarget dispersal. Therapeutic injection, with careful monitoring to identify early vascular stasis, may be safely performed beyond the origin of the patent GDA. A patent GDA with reversed flow provides forward drive for infused particles and may allow alternative access to the hepatic circulation.

  19. Ternary iron(II) complex with an emissive imidazopyridine arm from Schiff base cyclizations and its oxidative DNA cleavage activity.

    Science.gov (United States)

    Mukherjee, Arindam; Dhar, Shanta; Nethaji, Munirathinam; Chakravarty, Akhil R

    2005-01-21

    The ternary iron(II) complex [Fe(L')(L")](PF6)3(1) as a synthetic model for the bleomycins, where L' and L" are formed from metal-mediated cyclizations of N,N'-(2-hydroxypropane-1,3-diyl)bis(pyridine-2-aldimine)(L), is synthesized and structurally characterized by X-ray crystallography. In the six-coordinate iron(ii) complex, ligands L' and L" show tetradentate and bidentate chelating modes of bonding. Ligand L' is formed from an intramolecular attack of the alcoholic OH group of L to one imine moiety leading to the formation of a stereochemically constrained five-membered ring. Ligand L" which is formed from an intermolecular reaction involving one imine moiety of L and pyridine-2-carbaldehyde has an emissive cationic imidazopyridine pendant arm. The complex binds to double-stranded DNA in the minor groove giving a Kapp value of 4.1 x 10(5) M(-1) and displays oxidative cleavage of supercoiled DNA in the presence of H2O2 following a hydroxyl radical pathway. The complex also shows photo-induced DNA cleavage activity on UV light exposure involving formation of singlet oxygen as the reactive species.

  20. Melanoma Therapy with Rhenium-Cyclized Alpha Melanocyte Stimulating Hormone Peptide Analogs

    Energy Technology Data Exchange (ETDEWEB)

    Thomas P Quinn

    2005-11-22

    Malignant melanoma is the 6th most commonly diagnosed cancer with increasing incidence in the United States. It is estimated that 54,200 cases of malignant melanoma will be newly diagnosed and 7,600 cases of death will occur in the United States in the year 2003 (1). At the present time, more than 1.3% of Americans will develop malignant melanoma during their lifetime (2). The average survival for patients with metastatic melanoma is about 6-9 months (3). Moreover, metastatic melanoma deposits are resistant to conventional chemotherapy and external beam radiation therapy (3). Systematic chemotherapy is the primary therapeutic approach to treat patients with metastatic melanoma. Dacarbazine is the only single chemotherapy agent approved by FDA for metastatic melanoma treatment (5). However, the response rate to Dacarbazine is only approximately 20% (6). Therefore, there is a great need to develop novel treatment approaches for metastatic melanoma. The global goal of this research program is the rational design, characterization and validation of melanoma imaging and therapeutic radiopharmaceuticals. Significant progress has been made in the design and characterization of metal-cyclized radiolabeled alpha-melanocyte stimulating hormone peptides. Therapy studies with {sup 188}Re-CCMSH demonstrated the therapeutic efficacy of the receptor-targeted treatment in murine and human melanoma bearing mice (previous progress report). Dosimetry calculations, based on biodistribution data, indicated that a significant dose was delivered to the tumor. However, {sup 188}Re is a very energetic beta-particle emitter. The longer-range beta-particles theoretically would be better for larger tumors. In the treatment of melanoma, the larger primary tumor is usually surgically removed leaving metastatic disease as the focus of targeted radiotherapy. Isotopes with lower beta-energies and/or shorter particle lengths should be better suited for targeting metastases. The {sup 177}Lu

  1. Tyrosine-lipid peroxide adducts from radical termination: para coupling and intramolecular Diels-Alder cyclization.

    Science.gov (United States)

    Shchepin, Roman; Möller, Matias N; Kim, Hye-young H; Hatch, Duane M; Bartesaghi, Silvina; Kalyanaraman, Balaraman; Radi, Rafael; Porter, Ned A

    2010-12-15

    Free radical co-oxidation of polyunsaturated lipids with tyrosine or phenolic analogues of tyrosine gave rise to lipid peroxide-tyrosine (phenol) adducts in both aqueous micellar and organic solutions. The novel adducts were isolated and characterized by 1D and 2D NMR spectroscopy as well as by mass spectrometry (MS). The spectral data suggest that the polyunsaturated lipid peroxyl radicals give stable peroxide coupling products exclusively at the para position of the tyrosyl (phenoxy) radicals. These adducts have characteristic (13)C chemical shifts at 185 ppm due to the cross-conjugated carbonyl of the phenol-derived cyclohexadienone. The primary peroxide adducts subsequently undergo intramolecular Diels-Alder (IMDA) cyclization, affording a number of diastereomeric tricyclic adducts that have characteristic carbonyl (13)C chemical shifts at ~198 ppm. All of the NMR HMBC and HSQC correlations support the structure assignments of the primary and Diels-Alder adducts, as does MS collision-induced dissociation data. Kinetic rate constants and activation parameters for the IMDA reaction were determined, and the primary adducts were reduced with cuprous ion to give a phenol-derived 4-hydroxycyclohexa-2,5-dienone. No products from adduction of peroxyls at the phenolic ortho position were found in either the primary or cuprous reduction product mixtures. These studies provide a framework for understanding the nature of lipid-protein adducts formed by peroxyl-tyrosyl radical-radical termination processes. Coupling of lipid peroxyl radicals with tyrosyl radicals leads to cyclohexenone and cyclohexadienone adducts, which are of interest in and of themselves since, as electrophiles, they are likely targets for protein nucleophiles. One consequence of lipid peroxyl reactions with tyrosyls may therefore be protein-protein cross-links via interprotein Michael adducts.

  2. Dysphagia among Adult Patients who Underwent Surgery for Esophageal Atresia at Birth

    Directory of Open Access Journals (Sweden)

    Valérie Huynh-Trudeau

    2015-01-01

    Full Text Available BACKGROUND: Clinical experiences of adults who underwent surgery for esophageal atresia at birth is limited. There is some evidence that suggests considerable long-term morbidity, partly because of dysphagia, which has been reported in up to 85% of adult patients who undergo surgery for esophageal atresia. The authors hypothesized that dysphagia in this population is caused by dysmotility and/or anatomical anomalies.

  3. Reverse logistics - a framework

    NARCIS (Netherlands)

    M.P. de Brito (Marisa); R. Dekker (Rommert)

    2002-01-01

    textabstractIn this paper we define and compare Reverse Logistics definitions. We start by giving an understanding framework of Reverse Logistics: the why-what-how. By this means, we put in context the driving forces for Reverse Logistics, a typology of return reasons, a classification of

  4. Tubal Ligation Reversal

    Science.gov (United States)

    ... seal off the fallopian tubes, such as the Essure or Adiana systems, generally aren't reversible. Why ... electrocautery). Some types of sterilization, such as the Essure or Adiana systems, aren't considered reversible. Risks ...

  5. Management of Refractory Noninsulinoma Pancreatogenous Hypoglycemia Syndrome with Gastric Bypass Reversal: A Case Report and Review of the Literature

    Directory of Open Access Journals (Sweden)

    Bhavana B. Rao

    2015-01-01

    Full Text Available Background. Roux-en-Y gastric bypass (RYGB is a commonly performed, effective bariatric procedure; however, rarely, complications such as postprandial hypoglycemia due to noninsulinoma pancreatogenous hypoglycemia syndrome (NIPHS may ensue. Management of refractory NIPHS is challenging. We report a case that was successfully treated with RYGB reversal. Case Report. A 58-year-old male with history of RYGB nine months earlier for morbid obesity presented for evaluation of postprandial, hypoglycemic seizures. Testing for insulin level, insulin antibodies, oral hypoglycemic agents, pituitary axis hormone levels, and cortisol stimulation was unrevealing. Computed tomography (CT scan of the abdomen was unremarkable. A 72-hour fast was completed without hypoglycemia. Mixed meal testing demonstrated endogenous hyperinsulinemic hypoglycemia (EHH and selective arterial calcium stimulation testing (SACST was positive. Strict dietary modifications, maximal medical therapy, gastrostomy tube feeding, and stomal reduction failed to alleviate symptoms. Ultimately, he underwent laparoscopic reversal of RYGB. Now, 9 months after reversal, he has markedly reduced hypoglycemia burden. Discussion. Hyperfunctioning islets secondary to exaggerated incretin response and altered intestinal nutrient delivery are hypothesized to be causative in NIPHS. For refractory cases, there is increasing skepticism about the safety and efficacy of pancreatic resection. RYGB reversal may be successful.

  6. Reverse redistribution of thallium-201: a sign of nontransmural myocardial infarction with patency of the infarct-related coronary artery

    International Nuclear Information System (INIS)

    Weiss, A.T.; Maddahi, J.; Lew, A.S.; Shah, P.K.; Ganz, W.; Swan, H.J.; Berman, D.S.

    1986-01-01

    The pattern of reverse redistribution on the day 10 poststreptokinase resting thallium-201 myocardial scintigrams is a common finding in patients who have undergone streptokinase therapy in evolving myocardial infarction. To investigate this phenomenon, 67 patients who underwent streptokinase therapy were studied pre- and 10 days poststreptokinase therapy resting thallium-201 studies, poststreptokinase therapy resting radionuclide ventriculography and coronary arteriography (60 of the 67 patients). Of the 67 patients, 50 (75%) showed the reverse redistribution pattern on the day 10 thallium-201 study (Group I), 9 (13%) had a nonreversible defect (Group II) and the remaining 8 (12%) had a normal study or showed a reversible defect (Group III). The reverse redistribution pattern was associated with patency of the infarct-related artery (100%), quantitative improvement in resting thallium-201 defect size from day 1 to day 10 study (94%) and normal or near normal wall motion on day 10 radionuclide ventriculography (80% of segments with marked and 54% of those with mild reverse redistribution). In contrast, nonreversible defects were associated with significantly less frequent patency of the infarct-related artery (67%, p = 0.01), improvement in defect size (11%, p less than 0.001) and normal or near normal wall motion (21%, p less than 0.05). Group III patients were similar to Group I with respect to these variables. The quantitated thallium-201 percent washout was higher in the regions with the reverse redistribution pattern (49 +/- 15%) compared with the contralateral normal zone (24 +/- 15%, p less than 0.001)

  7. 49 CFR 230.89 - Reverse gear.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Reverse gear. 230.89 Section 230.89 Transportation... Reversing Gear § 230.89 Reverse gear. (a) General provisions. Reverse gear, reverse levers, and quadrants... quadrant. Proper counterbalance shall be provided for the valve gear. (b) Air-operated power reverse gear...

  8. Impact of Polypharmacy on Adherence to Evidence-Based Medication in Patients who Underwent Percutaneous Coronary Intervention.

    Science.gov (United States)

    Mohammed, Shaban; Arabi, Abdulrahaman; El-Menyar, Ayman; Abdulkarim, Sabir; AlJundi, Amer; Alqahtani, Awad; Arafa, Salah; Al Suwaidi, Jassim

    2016-01-01

    The primary objective of this study was to evaluate the impact of polypharmacy on primary and secondary adherence to evidence-based medication (EBM) and to measure factors associated with non-adherence among patients who underwent percutaneous coronary intervention (PCI). We conducted a retrospective analysis for patients who underwent PCI at a tertiary cardiac care hospital in Qatar. Patients who had polypharmacy (defined as ≥6 medications) were compared with those who had no polypharmacy at hospital discharge in terms of primary and secondary adherence to dual antiplatelet therapy (DAPT), beta-blockers (BB), angiotensin converting enzyme inhibitors (ACEIs) and statins. A total of 557 patients (mean age: 53±10 years; 85%; males) who underwent PCI were included. The majority of patients (84.6%) received ≥6 medications (polypharmacy group) while only 15.4% patients received ≥5 medications (nonpolypharmacy group). The two groups were comparable in term of gender, nationality, socioeconomic status and medical insurance. The non-polypharmacy patients had significantly higher adherence to first refill of DAPT compared with patients in the polypharmacy group (100 vs. 76.9%; p=0.001). Similarly, the non-polypharmacy patients were significantly more adherent to secondary preventive medications (BB, ACEI and statins) than the polypharmacy group. In patients who underwent PCI, polypharmacy at discharge could play a negative role in the adherence to the first refill of EBM. Further studies should investigate other parameters that contribute to long term non-adherence.

  9. A ruthenium(II) complex as turn-on Cu(II) luminescent sensor based on oxidative cyclization mechanism and its application in vivo

    Science.gov (United States)

    Zhang, Yunfei; Liu, Zonglun; Yang, Kui; Zhang, Yi; Xu, Yongqian; Li, Hongjuan; Wang, Chaoxia; Lu, Aiping; Sun, Shiguo

    2015-02-01

    Copper ions play a vital role in a variety of fundamental physiological processes not only in human beings and plants, but also for extensive insects and microorganisms. In this paper, a novel water-soluble ruthenium(II) complex as a turn-on copper(II) ions luminescent sensor based on o-(phenylazo)aniline was designed and synthesized. The azo group would undergo a specific oxidative cyclization reaction with copper(II) ions and turn into high luminescent benzotriazole, triggering significant luminescent increasements which were linear to the concentrations of copper(II) ions. The sensor distinguished by its high sensitivity (over 80-fold luminescent switch-on response), good selectivity (the changes of the emission intensity in the presence of other metal ions or amino acids were negligible) and low detection limit (4.42 nM) in water. Moreover, the copper(II) luminescent sensor exhibited good photostability under light irradiation. Furthermore, the applicability of the proposed sensor in biological samples assay was also studied and imaged copper(II) ions in living pea aphids successfully.

  10. Reversible Communicating Processes

    Directory of Open Access Journals (Sweden)

    Geoffrey Brown

    2016-02-01

    Full Text Available Reversible distributed programs have the ability to abort unproductive computation paths and backtrack, while unwinding communication that occurred in the aborted paths. While it is natural to assume that reversibility implies full state recovery (as with traditional roll-back recovery protocols, an interesting alternative is to separate backtracking from local state recovery. For example, such a model could be used to create complex transactions out of nested compensable transactions where a programmer-supplied compensation defines the work required to "unwind" a transaction. Reversible distributed computing has received considerable theoretical attention, but little reduction to practice; the few published implementations of languages supporting reversibility depend upon a high degree of central control. The objective of this paper is to demonstrate that a practical reversible distributed language can be efficiently implemented in a fully distributed manner. We discuss such a language, supporting CSP-style synchronous communication, embedded in Scala. While this language provided the motivation for the work described in this paper, our focus is upon the distributed implementation. In particular, we demonstrate that a "high-level" semantic model can be implemented using a simple point-to-point protocol.

  11. Factors related to postoperative pain among patients who underwent radiofrequency ablation of hepatocellular carcinoma

    International Nuclear Information System (INIS)

    Hsieh, Y.-C.; Yap, Y.-S.; Hung, C.-H.; Chen, C.-H.; Lu, S.-N.; Wang, J.-H.

    2013-01-01

    Aim: To evaluate the incidence and associated factors of postoperative intense pain and haemodynamic changes during radiofrequency ablation of hepatocellular carcinoma. Materials and methods: A total of 123 consecutive hepatocellular carcinoma patients who underwent radiofrequency ablation were prospectively recruited. Patient factors, tumour characteristics, procedural factors, intraoperative haemodynamic changes, complications, postoperative events, laboratory values before and after ablation, and postoperative pain were evaluated. Postoperative pain was scored using a visual analogue scale after the procedure. Results: The mean age of the patients was 65.6 ± 9.6 years. In multiple logistic regression analysis, patients who underwent general anaesthesia [odds ratio (95% CI): 2.68 (1.23–5.81); p = 0.013] and had more postoperative nausea and vomiting episodes [3.10 (1.11–8.63); p = 0.036] were associated with intense pain. These findings remain robust after propensity score matching. For mean difference values between before and after RFA, higher in change in aspartate transaminase (p = 0.026), alanine transaminase (p = 0.016) and white blood cell count (p = 0.015), and lower in change in haemoglobin (p = 0.009) were also correlated with intense pain. There was no significant difference in haemodynamic changes between the general anaesthesia and local anaesthesia group during ablation. Conclusion: General anaesthesia, postoperative nausea and vomiting, and laboratory factors were associated with postoperative intense pain in patients who underwent radiofrequency ablation. Counselling and modification of analgesics should be considered in patients with related factors for intense pain

  12. Intestinal myoelectric activity and contractile motility in dogs with a reversed jejunal segment after extensive small bowel resection.

    Science.gov (United States)

    Uchiyama, M; Iwafuchi, M; Ohsawa, Y; Yagi, M; Iinuma, Y; Ohtani, S

    1992-06-01

    To evaluate the functioning and effectiveness of a reversed jejunal segment after extensive small bowel resection, we continuously measured the postoperative bowel motility (using bipolar electrodes and/or contractile strain gage force transducers) in interdigestive and postprandial conscious dogs at 2 to 5 weeks after surgery. The fasting duodenal migrating myoelectric (or motor) complex (MMC) occurred at markedly longer intervals in dogs with a 20-cm reversed jejunal segment created after 75% to 80% extensive small bowel resection (group 3) than in dogs that received extensive resection alone (group 2) or dogs that underwent construction of a reversed jejunal segment without bowel resection (group 1). The MMC arising from the duodenum was often interrupted at the jejunum above the proximal anastomosis and did not migrate smoothly to the reversed segment or terminal ileum in group 3. In addition, brief small discordant contractions were frequent in the reversed segment and the jejunum above the proximal anastomosis in group 3. The duration of the postprandial period without duodenal MMC activity was significantly prolonged in groups 2 and 3. These results suggest that the transit time and passage of intestinal contents were delayed and that the periodical MMC was disturbed in group 3. The delay of transit time was due to prolongation of the interval between duodenal MMCs, the interruption of MMC propagation at the jejunum above the proximal anastomosis, the dominance of MMCs that followed the inherent anatomical continuity of the bowel, and discordant movements across the proximal anastomosis. Functional obstruction could be a potential problem in a 20-cm reversed jejunal segment inserted after extensive small bowel resection.

  13. The Geomagnetic Field During a Reversal

    Science.gov (United States)

    Heirtzler, James R.

    2003-01-01

    By modifying the IGRF it is possible to learn what may happen to the geomagnetic field during a geomagnetic reversal. If the entire IGRF reverses then the declination and inclination only reverse when the field strength is zero. If only the dipole component of the IGRF reverses a large geomagnetic field remains when the dipole component is zero and he direction of the field at the end of the reversal is not exactly reversed from the directions at the beginning of the reversal.

  14. Biomimetic transformation and biological activities of Globiferin, a terpenoid benzoquinone from Cordia globifera.

    Science.gov (United States)

    Dettrakul, Suppamit; Surerum, Sanya; Rajviroongit, Shuleewan; Kittakoop, Prasat

    2009-05-22

    A new 10-membered ring meroterpene (1), named globiferin, was isolated from root extracts of Cordia globifera. Biomimetic transformations of 1 and its derivatives, either by acid cyclization or by Cope rearrangement, provided information relating to the biogenesis of cordiachromes A-C. Globiferin (1) underwent Cope rearrangement upon refluxing in xylene and DMSO-d(6) to yield cordiachrome C (3) and cordiaquinol C (4), respectively. Heating in DMSO-d(6) resulted in an unexpected reduction of a quinone moiety. Globiferin diacetate (1b) cyclized under acidic conditions to give compounds 10 and 11, respective derivatives of natural cordiachromes B (2) and A (12). The present study indicates that globiferin (1) is a genuine intermediate for the biosynthesis of cordiachromes in Cordia species. Compounds 1 and 3 exhibited significant antimycobacterial activity, with MIC values of 6.2 and 1.5 mug/mL, respectively. Antimalarial, antifungal, and cytotoxic activities of 1 and its derivatives were also evaluated.

  15. Muscular activation during reverse and non-reverse chewing cycles in unilateral posterior crossbite.

    Science.gov (United States)

    Piancino, Maria Grazia; Farina, Dario; Talpone, Francesca; Merlo, Andrea; Bracco, Pietro

    2009-04-01

    The aim of this study was to characterize the kinematics and masseter muscle activation in unilateral posterior crossbite. Eighty-two children (8.6 +/- 1.3 yr of age) with unilateral posterior crossbite and 12 children (8.9 +/- 0.6 yr of age) with normal occlusion were selected for the study. Electromyography (EMG) and kinematics were concurrently recorded during mastication of a soft bolus and a hard bolus. The percentage of reverse cycles in the group of patients was 59.0 +/- 33.1% (soft bolus) and 69.7 +/- 29.7% (hard bolus) when chewing on the crossbite side. When chewing on the non-affected side, the number of reverse cycles was 16.7 +/- 24.5% (soft bolus) and 16.7 +/- 22.3% (hard bolus). The reverse cycles on the crossbite side were narrower with respect to the cycles on the non-affected side. Although both types of cycles in patients resulted in lower EMG activity of the masseter of the crossbite side than of the contralateral masseter, the activity of the non-affected side was larger for reverse than for non-reverse cycles. It was concluded that when chewing on the crossbite side, the masseter activity is reduced on the mastication side (crossbite) and is unaltered (non-reverse cycles) or increased (reverse) on the non-affected side.

  16. The Causes of Preference Reversal.

    OpenAIRE

    Tversky, Amos; Slovic, Paul; Kahneman, Daniel

    1990-01-01

    Observed preference reversal cannot be adequately explained by violations of independence, the reduction axiom, or transitivity. The primary cause of preference reversal is the failure of procedure invariance, especially the overpricing of low-probability, high-payoff bets. This result violates regret theory and generalized (nonindependent) utility models. Preference reversal and a new reversal involving time preferences are explained by scale compatibility, which implies that payoffs are wei...

  17. Laparoscopic pancreaticoduodenectomy via a reverse-''V'' approach with four ports: initial experience and perioperative outcomes.

    Science.gov (United States)

    Liu, Zhao; Yu, Mu-Chuan; Zhao, Rui; Liu, Yan-Feng; Zeng, Jian-Ping; Wang, Xian-Qiang; Tan, Jing-Wang

    2015-02-07

    To evaluate the feasibility, safety, and efficacy of laparoscopic pancreaticoduodenectomy (LPD) using a reverse-"V" approach with four ports. This is a retrospective study of selected patients who underwent LPD at our center between April 2011 and April 2012. The following data were collected and reviewed: patient characteristics, tumor histology, surgical outcome, resection margins, morbidity, and mortality. All patients were thoroughly evaluated preoperatively by complete hematologic investigations, triple-phase helical computed tomography, upper gastrointestinal endoscopy, and biopsy of ampullary lesions (when present). Magnetic resonance cholangiopancreatography was performed for doubtful cases of lower common bile duct lesions. There was no perioperative mortality. LPD was performed with tumor-free margins in all patients, including patients with pancreatic ductal adenocarcinoma (n = 6), ampullary carcinoma (n = 6), intra-ductal papillary mucinous neoplasm (n = 2), pancreatic cystadenocarcinoma (n = 2), pancreatic head adenocarcinoma (n = 3), and bile duct cancer (n = 2). The mean patient age was 65 years (range, 42-75 years). The median blood loss was 240 mL, and the mean operative time was 368 min. LPD using a reverse-"V" approach can be performed safely and yields good results in elective patients. Our preliminary experience showed that LDP can be performed via a reverse-"V" approach. This approach can be used to treat localized malignant lesions irrespective of histopathology.

  18. Melanoma targeting with alpha-melanocyte stimulating hormone analogs labeled with fac-[99mTc(CO)3]+: effect of cyclization on tumor-seeking properties.

    Science.gov (United States)

    Raposinho, Paula D; Xavier, Catarina; Correia, João D G; Falcão, Soraia; Gomes, Paula; Santos, Isabel

    2008-03-01

    Early detection of primary melanoma tumors is essential because there is no effective treatment for metastatic melanoma. Several linear and cyclic radiolabeled alpha-melanocyte stimulating hormone (alpha-MSH) analogs have been proposed to target the melanocortin type 1 receptor (MC1R) overexpressed in melanoma. The compact structure of a rhenium-cyclized alpha-MSH analog (Re-CCMSH) significantly enhanced its in vivo tumor uptake and retention. Melanotan II (MT-II), a cyclic lactam analog of alpha-MSH (Ac-Nle-cyclo[Asp-His-DPhe-Arg-Trp-Lys]-NH2]), is a very potent and stable agonist peptide largely used in the characterization of melanocortin receptors. Taking advantage of the superior biological features associated with the MT-II cyclic peptide, we assessed the effect of lactam-based cyclization on the tumor-seeking properties of alpha-MSH analogs by comparing the pharmacokinetics profile of the 99mTc-labeled cyclic peptide betaAla-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-NH2 with that of the linear analog betaAla-Nle-Asp-His-DPhe-Arg-Trp-Lys-NH2 in melanoma-bearing mice. We have synthesized and coupled the linear and cyclic peptides to a bifunctional chelator containing a pyrazolyl-diamine backbone (pz) through the amino group of betaAla, and the resulting pz-peptide conjugates were reacted with the fac-[99mTc(CO)3]+ moiety. The 99mTc(CO)3-labeled conjugates were obtained in high yield, high specific activity, and high radiochemical purity. The cyclic 99mTc(CO)3-labeled conjugate presents a remarkable internalization (87.1% of receptor-bound tracer and 50.5% of total applied activity, after 6 h at 37 degrees C) and cellular retention (only 24.7% released from the cells after 5 h) in murine melanoma B16F1 cells. A significant tumor uptake and retention was obtained in melanoma-bearing C57BL6 mice for the cyclic radioconjugate [9.26 +/- 0.83 and 11.31 +/- 1.83% ID/g at 1 and 4 h after injection, respectively]. The linear 99mTc(CO)3-pz-peptide presented lower values for

  19. Effects of the amino acid linkers on the melanoma-targeting and pharmacokinetic properties of 111In-labeled lactam bridge-cyclized alpha-MSH peptides.

    Science.gov (United States)

    Guo, Haixun; Yang, Jianquan; Gallazzi, Fabio; Miao, Yubin

    2011-04-01

    The purpose of this study was to examine the profound effects of the amino acid linkers on the melanoma-targeting and pharmacokinetic properties of (111)In-labeled lactam bridge-cyclized DOTA-[X]-CycMSH(hex) {1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid-[X]-c[Asp-His-dPhe-Arg-Trp-Lys]-CONH(2); X = GGNle, GENle, or NleGE; GG = -Gly-Gly- and GE = -Gly-Glu-} peptides. Three novel peptides (DOTA-GGNle-CycMSH(hex), DOTA-GENle-CycMSH(hex), and DOTA-NleGE-CycMSH(hex)) were designed and synthesized. The melanocortin-1 (MC1) receptor-binding affinities of the peptides were determined in B16/F1 melanoma cells. The melanoma-targeting and pharmacokinetic properties of (111)In-DOTA-GGNle-CycMSH(hex) and (111)In-DOTA-GENle-CycMSH(hex) were determined in B16/F1 melanoma-bearing C57 mice. DOTA-GGNle-CycMSH(hex) and DOTA-GENle-CycMSH(hex) displayed 2.1 and 11.5 nM MC1 receptor-binding affinities, whereas DOTA-NleGE-CycMSH(hex) showed 873.4 nM MC1 receptor-binding affinity. The introduction of the -GG- linker maintained high melanoma uptake while decreasing kidney and liver uptake of (111)In-DOTA-GGNle-CycMSH(hex). The tumor uptake of (111)In-DOTA-GGNle-CycMSH(hex) was 19.05 ± 5.04 and 18.6 ± 3.56 percentage injected dose per gram at 2 and 4 h after injection, respectively. (111)In-DOTA-GGNle-CycMSH(hex) exhibited 28%, 32%, and 42% less kidney uptake than (111)In-DOTA-Nle-CycMSH(hex) we reported previously, and 61%, 65%, and 68% less liver uptake than (111)In-DOTA-Nle-CycMSH(hex) at 2, 4, and 24 h after injection, respectively. The amino acid linkers exhibited profound effects on the melanoma-targeting and pharmacokinetic properties of the (111)In-labeled lactam bridge-cyclized α-melanocyte-stimulating hormone peptides. Introduction of the -GG- linker maintained high melanoma uptake while reducing kidney and liver uptake of (111)In-DOTA-GGNle-CycMSH(hex), highlighting its potential as an effective imaging probe for melanoma detection, as well as a therapeutic peptide

  20. AMPK Activation Prevents and Reverses Drug-Induced Mitochondrial and Hepatocyte Injury by Promoting Mitochondrial Fusion and Function.

    Directory of Open Access Journals (Sweden)

    Sun Woo Sophie Kang

    Full Text Available Mitochondrial damage is the major factor underlying drug-induced liver disease but whether conditions that thwart mitochondrial injury can prevent or reverse drug-induced liver damage is unclear. A key molecule regulating mitochondria quality control is AMP activated kinase (AMPK. When activated, AMPK causes mitochondria to elongate/fuse and proliferate, with mitochondria now producing more ATP and less reactive oxygen species. Autophagy is also triggered, a process capable of removing damaged/defective mitochondria. To explore whether AMPK activation could potentially prevent or reverse the effects of drug-induced mitochondrial and hepatocellular damage, we added an AMPK activator to collagen sandwich cultures of rat and human hepatocytes exposed to the hepatotoxic drugs, acetaminophen or diclofenac. In the absence of AMPK activation, the drugs caused hepatocytes to lose polarized morphology and have significantly decreased ATP levels and viability. At the subcellular level, mitochondria underwent fragmentation and had decreased membrane potential due to decreased expression of the mitochondrial fusion proteins Mfn1, 2 and/or Opa1. Adding AICAR, a specific AMPK activator, at the time of drug exposure prevented and reversed these effects. The mitochondria became highly fused and ATP production increased, and hepatocytes maintained polarized morphology. In exploring the mechanism responsible for this preventive and reversal effect, we found that AMPK activation prevented drug-mediated decreases in Mfn1, 2 and Opa1. AMPK activation also stimulated autophagy/mitophagy, most significantly in acetaminophen-treated cells. These results suggest that activation of AMPK prevents/reverses drug-induced mitochondrial and hepatocellular damage through regulation of mitochondrial fusion and autophagy, making it a potentially valuable approach for treatment of drug-induced liver injury.

  1. AMPK Activation Prevents and Reverses Drug-Induced Mitochondrial and Hepatocyte Injury by Promoting Mitochondrial Fusion and Function

    Science.gov (United States)

    Taniane, Caitlin; Farrell, Geoffrey; Arias, Irwin M.; Lippincott-Schwartz, Jennifer; Fu, Dong

    2016-01-01

    Mitochondrial damage is the major factor underlying drug-induced liver disease but whether conditions that thwart mitochondrial injury can prevent or reverse drug-induced liver damage is unclear. A key molecule regulating mitochondria quality control is AMP activated kinase (AMPK). When activated, AMPK causes mitochondria to elongate/fuse and proliferate, with mitochondria now producing more ATP and less reactive oxygen species. Autophagy is also triggered, a process capable of removing damaged/defective mitochondria. To explore whether AMPK activation could potentially prevent or reverse the effects of drug-induced mitochondrial and hepatocellular damage, we added an AMPK activator to collagen sandwich cultures of rat and human hepatocytes exposed to the hepatotoxic drugs, acetaminophen or diclofenac. In the absence of AMPK activation, the drugs caused hepatocytes to lose polarized morphology and have significantly decreased ATP levels and viability. At the subcellular level, mitochondria underwent fragmentation and had decreased membrane potential due to decreased expression of the mitochondrial fusion proteins Mfn1, 2 and/or Opa1. Adding AICAR, a specific AMPK activator, at the time of drug exposure prevented and reversed these effects. The mitochondria became highly fused and ATP production increased, and hepatocytes maintained polarized morphology. In exploring the mechanism responsible for this preventive and reversal effect, we found that AMPK activation prevented drug-mediated decreases in Mfn1, 2 and Opa1. AMPK activation also stimulated autophagy/mitophagy, most significantly in acetaminophen-treated cells. These results suggest that activation of AMPK prevents/reverses drug-induced mitochondrial and hepatocellular damage through regulation of mitochondrial fusion and autophagy, making it a potentially valuable approach for treatment of drug-induced liver injury. PMID:27792760

  2. Experimental and theoretical characterization of organic salt: 2-((4-bromophenyl)amino) pyrido[1,2-a] quinoxalin-11-ium bromide monohydrate synthesized via oxidative cyclization

    Science.gov (United States)

    Faizi, Md. Serajul Haque; Alam, Mohammad Jane; Haque, Ashanul; Ahmad, Shabbir; Shahid, M.; Ahmad, Musheer

    2018-03-01

    Quinoxalines are nitrogen-embedded heterocyclic compounds that possess unique and versatile pharmacological applications. The present article describes synthesis and characterization of organic salt 2-((4-bromophenyl)amino)pyrido [1,2-a]quinoxalin-11-ium bromide (BAPQ), an oxidative cyclized product of N-phenyl-N-(pyridine-2-ylmethylene)benzene-1,4-diamine (PPMD). The structure of the synthesized product was extensively characterized by 1H NMR, 2D-COSY NMR, MS, IR, UV-vis, X-ray techniques and elemental analysis. The electronic and structural properties of BAPQ was well complemented by performing extensive computational studies (B3LYP/6-311G (d,p) basis sets). Metal-free, mild reaction condition, easy work-up and excellent yield with high purity are main features of this work and thus holds promise for the generation of new compounds of this class. Analytical results indicated ionic nature of the compound with bromide as counterion. DFT calculation showed low kinetic stability and high reactivity of the compound.

  3. Copper-Assisted Oxidative Trifluoromethylthiolation of 2,3-Allenoic Acids with AgSCF3.

    Science.gov (United States)

    Pan, Shen; Huang, Yangen; Xu, Xiu-Hua; Qing, Feng-Ling

    2017-09-01

    The oxidative trifluoromethylthiolation of 2,3-allenoic acids with AgSCF 3 in the presence of (NH 4 ) 2 S 2 O 8 and catalytic copper salt was investigated. A series of 4-aryl-2,3-allenoic acids underwent radical trifluoromethylthiolation/intramolecular cyclization to afford β-trifluoromethylthiolated butenolides, which were conveniently transformed into trifluoromethylthiolated furan derivatives. In contrast, 2-monosubstituted 2,3-allenoic acids were converted into the corresponding 3,4-bis(trifluoromethylthio)but-2-enoic-acids under similar reaction conditions.

  4. Reverse logistics policy – differences between conservative and innovative reverse logistics management

    Directory of Open Access Journals (Sweden)

    Alena Klapalová

    2013-01-01

    Full Text Available One of the of the key barriers that hampers effective and efficient management of reverse flows detected within a number of empirical surveys and case studies focused on reverse logistics and/or return management is business (organisational policy, specifically lack of policy, deficiency in existing policy or inferior policy. Despite this fact, there is a gap in literature which would show some evidence from practice that innovative reverse logistics policy both can pay off and is associated with certain aspects of reverse logistics management. Such proof can have several implications. It can support the call for better understanding and more research of the linkages of reverse logistics with other corporate functions, promote the acceptation of strategic character of reverse logistics and stress the role of RL policy within the rest of overall corporate management.The aim of this paper is to contribute and to enrich the existing body of knowledge concerning the above-mentioned gap through presentation of survey results that was realized in 2012 among managers of 244 Czech firms. The results demonstrate the statistically significant association between the innovativeness of RL policy and profitability of firms, quality of RL planning, perception of RL importance, level of RL knowledge and perception of product innovation importance for firms’ competitiveness and frequency of product innovation. They also reveal statistically significant differences between firms with conservative and innovative RL policy and the perceived existence of some barriers to manage RL.

  5. Geomagnetic Field During a Reversal

    Science.gov (United States)

    Heirtzler, J. R.

    2003-01-01

    It has frequently been suggested that only the geomagnetic dipole, rather than higher order poles, reverse during a geomagnetic field reversal. Under this assumption the geomagnetic field strength has been calculated for the surface of the Earth for various steps of the reversal process. Even without an eminent a reversal of the field, extrapolation of the present secular change (although problematic) shows that the field strength may become zero in some geographic areas within a few hundred years.

  6. Supercritical fluid reverse micelle separation

    Science.gov (United States)

    Fulton, J.L.; Smith, R.D.

    1993-11-30

    A method of separating solute material from a polar fluid in a first polar fluid phase is provided. The method comprises combining a polar fluid, a second fluid that is a gas at standard temperature and pressure and has a critical density, and a surfactant. The solute material is dissolved in the polar fluid to define the first polar fluid phase. The combined polar and second fluids, surfactant, and solute material dissolved in the polar fluid is maintained under near critical or supercritical temperature and pressure conditions such that the density of the second fluid exceeds the critical density thereof. In this way, a reverse micelle system defining a reverse micelle solvent is formed which comprises a continuous phase in the second fluid and a plurality of reverse micelles dispersed in the continuous phase. The solute material is dissolved in the polar fluid and is in chemical equilibrium with the reverse micelles. The first polar fluid phase and the continuous phase are immiscible. The reverse micelles each comprise a dynamic aggregate of surfactant molecules surrounding a core of the polar fluid. The reverse micelle solvent has a polar fluid-to-surfactant molar ratio W, which can vary over a range having a maximum ratio W[sub o] that determines the maximum size of the reverse micelles. The maximum ratio W[sub o] of the reverse micelle solvent is then varied, and the solute material from the first polar fluid phase is transported into the reverse micelles in the continuous phase at an extraction efficiency determined by the critical or supercritical conditions. 27 figures.

  7. r-Universal reversible logic gates

    International Nuclear Information System (INIS)

    Vos, A de; Storme, L

    2004-01-01

    Reversible logic plays a fundamental role both in ultra-low power electronics and in quantum computing. It is therefore important to know which reversible logic gates can be used as building block for the reversible implementation of an arbitrary boolean function and which cannot

  8. Quantum reverse hypercontractivity

    Energy Technology Data Exchange (ETDEWEB)

    Cubitt, Toby [Department of Computer Science, University College London, London, United Kingdom and Centre for Quantum Information and Foundations, DAMTP, University of Cambridge, Cambridge (United Kingdom); Kastoryano, Michael [NBIA, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen (Denmark); Montanaro, Ashley [School of Mathematics, University of Bristol, Bristol (United Kingdom); Temme, Kristan [Institute for Quantum Information and Matter, California Institute of Technology, Pasadena, California 91125 (United States)

    2015-10-15

    We develop reverse versions of hypercontractive inequalities for quantum channels. By generalizing classical techniques, we prove a reverse hypercontractive inequality for tensor products of qubit depolarizing channels. We apply this to obtain a rapid mixing result for depolarizing noise applied to large subspaces and to prove bounds on a quantum generalization of non-interactive correlation distillation.

  9. Introduction to reversible computing

    CERN Document Server

    Perumalla, Kalyan S

    2013-01-01

    Few books comprehensively cover the software and programming aspects of reversible computing. Filling this gap, Introduction to Reversible Computing offers an expanded view of the field that includes the traditional energy-motivated hardware viewpoint as well as the emerging application-motivated software approach. Collecting scattered knowledge into one coherent account, the book provides a compendium of both classical and recently developed results on reversible computing. It explores up-and-coming theories, techniques, and tools for the application of rever

  10. A Study on Reverse Logistics

    OpenAIRE

    Reddy, Dhananjaya

    2011-01-01

    In the competitive world of manufacturing, companies are often searching for new ways to improve their process, customer satisfaction and stay ahead in the game with their competitors. Reverse logistics has been considered a strategy to bring these things to life for the past decade or so. This thesis work tries to shed some light on the basics of reverse logistics and how reverse logistics can be used as a management strategy. This paper points out the fundamentals of reverse logistics and l...

  11. Understanding the mechanical properties of DNA origami tiles and controlling the kinetics of their folding and unfolding reconfiguration.

    Science.gov (United States)

    Chen, Haorong; Weng, Te-Wei; Riccitelli, Molly M; Cui, Yi; Irudayaraj, Joseph; Choi, Jong Hyun

    2014-05-14

    DNA origami represents a class of highly programmable macromolecules that can go through conformational changes in response to external signals. Here we show that a two-dimensional origami rectangle can be effectively folded into a short, cylindrical tube by connecting the two opposite edges through the hybridization of linker strands and that this process can be efficiently reversed via toehold-mediated strand displacement. The reconfiguration kinetics was experimentally studied as a function of incubation temperature, initial origami concentration, missing staples, and origami geometry. A kinetic model was developed by introducing the j factor to describe the reaction rates in the cyclization process. We found that the cyclization efficiency (j factor) increases sharply with temperature and depends strongly on the structural flexibility and geometry. A simple mechanical model was used to correlate the observed cyclization efficiency with origami structure details. The mechanical analysis suggests two sources of the energy barrier for DNA origami folding: overcoming global twisting and bending the structure into a circular conformation. It also provides the first semiquantitative estimation of the rigidity of DNA interhelix crossovers, an essential element in structural DNA nanotechnology. This work demonstrates efficient DNA origami reconfiguration, advances our understanding of the dynamics and mechanical properties of self-assembled DNA structures, and should be valuable to the field of DNA nanotechnology.

  12. Reversibility of Supraspinatus Muscle Atrophy in Tendon-Bone Healing After Arthroscopic Rotator Cuff Repair.

    Science.gov (United States)

    Park, Yong Bok; Ryu, Ho Young; Hong, Jin Ho; Ko, Young Hoo; Yoo, Jae Chul

    2016-04-01

    To date, there are few reports of the definite reversibility of rotator cuff muscle atrophy after repair. To evaluate the reversibility of rotator cuff muscle atrophy after successful arthroscopic repair. Case series; Level of evidence, 4. Included in this study were 47 patients (mean age, 61.2 ± 7.3 years; range, 49-73 years) who underwent arthroscopic rotator cuff repair as well as magnetic resonance imaging (MRI) preoperatively and at 6-month and last follow-up. Patients who had confirmed rotator cuff healing (grades 1-3 according to the Sugaya classification) on both series of postoperative MRI were enrolled in the study. The mean time from the onset of symptoms to surgery was 24.7 ± 25.6 months (range, 3-120 months). The minimum follow-up was 2 years, and the mean follow-up duration was 41.8 ± 14.4 months. Serial changes in the supraspinatus muscle area on the most matching MRI scans (sagittal-oblique view) were evaluated. The area was measured by 2 independent observers. Both independent observers reported no significant difference in the area of the supraspinatus muscle between the preoperative time point and 6-month follow-up (observer 1: P = .135; observer 2: P = .189). However, there was a significant difference between the 6-month and last follow-up (mean, 41.8 months; observers 1 and 2: P .999) or from 6-month to final follow-up (P = .077). After successful arthroscopic rotator cuff repair, there was a slight (11.3%-13.9%) increase in muscle volume from preoperatively to final follow-up, as seen on serial MRI. Fatty infiltration according to the Goutallier grade was not reversed (P = .077). Some reversibility of supraspinatus muscle atrophy may exist in tendon-bone healing after arthroscopic rotator cuff repair; further follow-up is needed to better elucidate this result. © 2016 The Author(s).

  13. Optimized reversible binary-coded decimal adders

    DEFF Research Database (Denmark)

    Thomsen, Michael Kirkedal; Glück, Robert

    2008-01-01

    Abstract Babu and Chowdhury [H.M.H. Babu, A.R. Chowdhury, Design of a compact reversible binary coded decimal adder circuit, Journal of Systems Architecture 52 (5) (2006) 272-282] recently proposed, in this journal, a reversible adder for binary-coded decimals. This paper corrects and optimizes...... their design. The optimized 1-decimal BCD full-adder, a 13 × 13 reversible logic circuit, is faster, and has lower circuit cost and less garbage bits. It can be used to build a fast reversible m-decimal BCD full-adder that has a delay of only m + 17 low-power reversible CMOS gates. For a 32-decimal (128-bit....... Keywords: Reversible logic circuit; Full-adder; Half-adder; Parallel adder; Binary-coded decimal; Application of reversible logic synthesis...

  14. Correction: β-Amyrin synthase from Euphorbia tirucalli L. functional analyses of the highly conserved aromatic residues Phe413, Tyr259 and Trp257 disclose the importance of the appropriate steric bulk, and cation-π and CH-π interactions for the efficient catalytic action of the polyolefin cyclization cascade.

    Science.gov (United States)

    Ito, Ryousuke; Nakada, Chika; Hoshino, Tsutomu

    2017-01-18

    Correction for 'β-Amyrin synthase from Euphorbia tirucalli L. functional analyses of the highly conserved aromatic residues Phe413, Tyr259 and Trp257 disclose the importance of the appropriate steric bulk, and cation-π and CH-π interactions for the efficient catalytic action of the polyolefin cyclization cascade' by Ryousuke Ito et al., Org. Biomol. Chem., 2017, 15, 177-188.

  15. What do reversible programs compute?

    DEFF Research Database (Denmark)

    Axelsen, Holger Bock; Glück, Robert

    2011-01-01

    Reversible computing is the study of computation models that exhibit both forward and backward determinism. Understanding the fundamental properties of such models is not only relevant for reversible programming, but has also been found important in other fields, e.g., bidirectional model...... transformation, program transformations such as inversion, and general static prediction of program properties. Historically, work on reversible computing has focussed on reversible simulations of irreversible computations. Here, we take the viewpoint that the property of reversibility itself should...... are not strictly classically universal, but that they support another notion of universality; we call this RTM-universality. Thus, even though the RTMs are sub-universal in the classical sense, they are powerful enough as to include a self-interpreter. Lifting this to other computation models, we propose r...

  16. Fundamentals of reversible flowchart languages

    DEFF Research Database (Denmark)

    Yokoyama, Tetsuo; Axelsen, Holger Bock; Glück, Robert

    2016-01-01

    Abstract This paper presents the fundamentals of reversible flowcharts. They are intended to naturally represent the structure and control flow of reversible (imperative) programming languages in a simple computation model, in the same way classical flowcharts do for conventional languages......, structured reversible flowcharts are as expressive as unstructured ones, as shown by a reversible version of the classic Structured Program Theorem. We illustrate how reversible flowcharts can be concretized with two example programming languages, complete with syntax and semantics: a low-level unstructured...... language and a high-level structured language. We introduce concrete tools such as program inverters and translators for both languages, which follow the structure suggested by the flowchart model. To further illustrate the different concepts and tools brought together in this paper, we present two major...

  17. Magnetic reversals from planetary dynamo waves

    DEFF Research Database (Denmark)

    Sheyko, Andrey; Finlay, Chris; Jackson, Andrew

    2016-01-01

    A striking feature of many natural dynamos is their ability to undergo polarity reversals. The best documented example is Earth's magnetic field, which has reversed hundreds of times during its history. The origin of geomagnetic polarity reversals lies in a magnetohydrodynamic process that takes ...... to kinematic dynamo waves. Because our results are relevant in a regime of low viscosity and high magnetic diffusivity, and with geophysically appropriate boundary conditions, this form of dynamo wave may also be involved in geomagnetic reversals.......A striking feature of many natural dynamos is their ability to undergo polarity reversals. The best documented example is Earth's magnetic field, which has reversed hundreds of times during its history. The origin of geomagnetic polarity reversals lies in a magnetohydrodynamic process that takes...... place in Earth's core, but the precise mechanism is debated. The majority of numerical geodynamo simulations that exhibit reversals operate in a regime in which the viscosity of the fluid remains important, and in which the dynamo mechanism primarily involves stretching and twisting of field lines...

  18. Effect of different pneumoperitoneum pressure on stress state in patients underwent gynecological laparoscopy

    Directory of Open Access Journals (Sweden)

    Ai-Yun Shen

    2016-10-01

    Full Text Available Objective: To observe the effect of different CO2 pneumoperitoneum pressure on the stress state in patients underwent gynecological laparoscopy. Methods: A total of 90 patients who were admitted in our hospital from February, 2015 to October, 2015 for gynecological laparoscopy were included in the study and divided into groups A, B, and C according to different CO2 pneumoperitoneum pressure. The changes of HR, BP, and PetCO2 during the operation process in the three groups were recorded. The changes of stress indicators before operation (T0, 30 min during operation (T1, and 12 h after operation (T2 were compared. Results: The difference of HR, BP, and PetCO2 levels before operation among the three groups was not statistically significant (P>0.05. HR, BP, and PetCO2 levels 30 min after pneumoperitoneum were significantly elevated when compared with before operation (P0.05. PetCO2 level 30 min after pneumoperitoneum in group B was significantly higher than that in group A (P0.05. Conclusions: Low pneumoperitoneum pressure has a small effect on the stress state in patients underwent gynecological laparoscopy, will not affect the surgical operation, and can obtain a preferable muscular relaxation and vision field; therefore, it can be selected in preference.

  19. Train-of-four recovery precedes twitch recovery during reversal with sugammadex in pediatric patients: A retrospective analysis.

    Science.gov (United States)

    Vieira Carlos, Ricardo; Luis Abramides Torres, Marcelo; de Boer, Hans Donald

    2018-04-01

    After reversal of a rocuronium-induced neuromuscular blockade with sugammadex, the recovery of train-of-four ratio to 0.9 is faster than recovery of first twitch of the train-of-four to 90% in adults. These findings after reversal of neuromuscular blockade with sugammadex have not yet been investigated in pediatric patients. The aim of this retrospective analysis was to investigate the relationship of the recovery of first twitch of the train-of-four height and train-of-four ratio after reversal of rocuronium-induced neuromuscular blockade with sugammadex in pediatric patients. Patients ASA I-III, aged 2-11 years, and who underwent abdominal and/or perineal surgery were included in the analysis. After extracting the necessary data from the hospital database, the patients were divided into 2 groups based on the dose of sugammadex received: group A: 2 mg.kg -1 for reversal of moderate neuromuscular blockade and group B: 4 mg.kg -1 for reversal of deep neuromuscular blockade. The relationship of the recovery of first twitch of the train-of-four height and train-of-four ratio in these 2 groups were analyzed. Data from 43 pediatric patients aged 2-11 years could be analyzed. The first twitch of the train-of-four height at the recovery of train-of-four ratio to 0.9 in group B was statistically significantly lower compared with group A. This height 3 and 5 minutes after the train-of-four ratio reached 0.9 showed no statistically significant differences between groups. The results were in line with the results found in adults and showed that the train-of-four ratio recovered to 0.9 was faster than first twitch of the train-of-four height recovered to the same level. © 2018 John Wiley & Sons Ltd.

  20. Caffeine reversal of ethanol effects on the multiple sleep latency test, memory, and psychomotor performance.

    Science.gov (United States)

    Drake, Christopher L; Roehrs, Timothy; Turner, Lauren; Scofield, Holly M; Roth, Thomas

    2003-02-01

    Caffeine has been shown to reverse some of the performance-impairing effects of ethanol. However, it is not known whether this antagonistic effect of caffeine is mediated by a reduction in sleepiness. The present study assessed physiological alertness/sleepiness, memory, and psychomotor performance following the administration of placebo, ethanol, and caffeine+ethanol combinations. A total of 13 healthy individuals (21-35 years old) underwent four conditions presented in a Latin Square Design: placebo-placebo, ethanol (0.5 g/kg)-placebo, ethanol (0.5 g/kg)-caffeine 150 mg, and ethanol (0.5 g/kg)-caffeine 300-mg. The Multiple Sleep Latency Test (MSLT), psychomotor performance battery, memory test, and mood/sleepiness questionnaires were administered following each condition. The peak breadth ethanol concentration (BrEC) was 0.043+/-0.0197% and did not differ among the three caffeine treatments. As expected, ethanol reduced mean latency on the MSLT. The lowest caffeine dose reversed this effect and the highest dose increased mean latency (greater alertness) significantly beyond placebo levels. Ethanol also impaired psychomotor performance and memory. The 300-mg caffeine dose restored performance and memory measures to placebo levels. Although visual analog ratings of dizziness were increased by ethanol, they were not diminished by either caffeine dose. In conclusion, Low-dose caffeine prevented the sleepiness and performance impairment associated with a moderate dose of ethanol. Thus, caffeine, similar to other stimulants, can reverse the physiologically sedating effects of ethanol, although other negative effects remain.

  1. IFN-γ release assay conversions and reversions. Challenges with serial testing in U.S. health care workers.

    Science.gov (United States)

    Joshi, Manish; Monson, Thomas P; Joshi, Anita; Woods, Gail L

    2014-03-01

    IFN-γ release assays (IGRAs) including the QuantiFERON-TB gold in-tube test (QFT-GIT) are increasingly used in place of the tuberculin skin test (TST) in surveillance programs for Mycobacterium tuberculosis infection in the United States. However, data on conversions, reversions, and predictive value of QFT in such programs for health care workers (HCWs) are limited. The purpose of this study is to assess long-term reproducibility and conversion and reversion rates of QFT-GIT among HCWs who underwent serial testing at a tertiary care center in the United States. Retrospective chart review of HCWs at the Central Arkansas Veterans Healthcare System (CAVHS) who underwent serial testing with QFT-GIT as a part of their employee screening between November 1, 2008 and January 31, 2011. A total of 2,303 HCWs had at least 2 QFT-GITs 1 year apart. The initial QFT-GIT was positive for 69 and 2 were indeterminate. Of these 69 HCWs, 31 (45%) reverted on repeat testing, and 25 of 31 (80.6%) HCWs who reverted had a negative look-back TST. Of the 2,232 HCWs with an initial negative QFT-GIT, 71 (3.2%) converted on repeat testing. A third QFT-GIT assay was performed in 41 of the 71 converters and 90% (37 of 41) reverted back to negative. Only two HCWs had TST and QFT-GIT conversion. Poor IGRA reproducibility and a low predictive value of QFT-GIT conversions indicate that QFT-GIT with current interpretation criteria should not be used for serial screening of U.S. HCWs. Negative TSTs have higher reproducibility than QFT-GIT for serial testing of HCWs in low tuberculosis incidence settings.

  2. A functional language for describing reversible logic

    DEFF Research Database (Denmark)

    Thomsen, Michael Kirkedal

    2012-01-01

    Reversible logic is a computational model where all gates are logically reversible and combined in circuits such that no values are lost or duplicated. This paper presents a novel functional language that is designed to describe only reversible logic circuits. The language includes high....... Reversibility of descriptions is guaranteed with a type system based on linear types. The language is applied to three examples of reversible computations (ALU, linear cosine transformation, and binary adder). The paper also outlines a design flow that ensures garbage- free translation to reversible logic...... circuits. The flow relies on a reversible combinator language as an intermediate language....

  3. Sugammadex is effective in reversing rocuronium in the presence of antibiotics.

    Science.gov (United States)

    Hudson, Mark E; Rietbergen, Henk; Chelly, Jacques E

    2014-01-01

    The effectiveness of sugammadex in reversing rocuronium-induced neuromuscular blockade (NMB) in the presence of drugs that may potentiate NMB remains to be fully established. The aim of this post-hoc analysis of data from a Phase III clinical trial (VISTA; NCT00298831) was to investigate the impact of antibiotics on recovery from rocuronium-induced NMB after administration of sugammadex for reversal, and compared the neuromuscular recovery in patients who received antibiotics preoperatively with those who did not. A Phase III, multicenter, open-label study designed to reflect potential use of sugammadex in clinical practice was conducted at 19 sites. Data obtained from patients who received antibiotics were compared with the cohort of patients who underwent the same protocol without antibiotics. Each subject received rocuronium 0.6 mg/kg for muscle relaxation, after which tracheal intubation was performed; patients were also permitted to receive maintenance doses of rocuronium 0.15 mg/kg to maintain the desired level of NMB throughout the operation, as required.. At least 15 min after the last rocuronium dose, patients received sugammadex 4.0 mg/kg for reversal. Neuromuscular monitoring was continued until a train-of-four (TOF) ratio of ≥0.9 was achieved or the anesthetic was discontinued. The presence of antibiotics prior to the administration of sugammadex did not affect the recovery time from rocuronium-induced NMB when sugammadex 4.0 mg/kg was administered at least 15 min after the last dose of rocuronium. In the presence of antibiotics, the geometric mean (95% CI) time from administration of sugammadex 4.0 mg/kg to recovery of the TOF ratio to ≥0.9 was 1.6 (1.4-1.9) min (range: 0.7-10.5 min), compared with 2.0 (1.8-2.3) min (range: 0.7-22.3 min) for patients who did not receive antibiotics. These findings suggest that prophylactic antibiotic use is unlikely to have a major impact on the recovery time from rocuronium-induced NMB with sugammadex

  4. Geomagnetic Reversals during the Phanerozoic.

    Science.gov (United States)

    McElhinny, M W

    1971-04-09

    An antalysis of worldwide paleomagnetic measurements suggests a periodicity of 350 x 10(6) years in the polarity of the geomagnetic field. During the Mesozoic it is predominantly normal, whereas during the Upper Paleozoic it is predominantly reversed. Although geomagnetic reversals occur at different rates throughout the Phanerozoic, there appeaars to be no clear correlation between biological evolutionary rates and reversal frequency.

  5. Resveratrol reverses morphine-induced neuroinflammation in morphine-tolerant rats by reversal HDAC1 expression

    Directory of Open Access Journals (Sweden)

    Ru-Yin Tsai

    2016-06-01

    Conclusion: Resveratrol restores the antinociceptive effect of morphine by reversing morphine infusion-induced spinal cord neuroinflammation and increase in TNFR1 expression. The reversal of the morphine-induced increase in TNFR1 expression by resveratrol is partially due to reversal of the morphine infusion-induced increase in HDAC1 expression. Resveratrol pretreatment can be used as an adjuvant in clinical pain management for patients who need long-term morphine treatment or with neuropathic pain.

  6. Elective Stoma Reversal Has a Higher Incidence of Postoperative Clostridium Difficile Infection Compared With Elective Colectomy: An Analysis Using the American College of Surgeons National Surgical Quality Improvement Program and Targeted Colectomy Databases.

    Science.gov (United States)

    Skancke, Matthew; Vaziri, Khashayar; Umapathi, Bindu; Amdur, Richard; Radomski, Michal; Obias, Vincent

    2018-05-01

    Clostridium difficile infection is caused by the proliferation of a gram-positive anaerobic bacteria after medical or surgical intervention and can result in toxic complications, emergent surgery, and death. This analysis evaluates the incidence of C difficile infection in elective restoration of intestinal continuity compared with elective colon resection. This was a retrospective database review of the 2015 American College of Surgeons National Surgical Quality Improvement Project and targeted colectomy database. The intervention cohort was defined as the primary Current Procedural Terminology codes for ileostomy/colostomy reversal (44227, 44620, 44625, and 44626) and International Classification of Diseases codes for ileostomy/colostomy status (VV44.2, VV44.3, VV55.2, VV55.3, Z93.2, Z93.3, Z43.3, and Z43.2). A total of 2235 patients underwent elective stoma reversal compared with 10403 patients who underwent elective colon resection. Multivariate regression modeling of the impact of stoma reversal on postoperative C difficile infection risk was used as the study intervention. The incidence of C difficile infection in the 30 days after surgery was measured. The incidence of C difficile infection in the 30-day postoperative period was significantly higher (3.04% vs 1.25%; p difficile infection incidence in the 30-day postoperative period. The study was limited because it was a retrospective database review with observational bias. Patients who undergo elective stoma reversal have a higher incidence of postoperative C difficile infection compared with patients who undergo an elective colectomy. Given the impact of postoperative C difficile infection, a heightened sense of suspicion should be given to symptomatic patients after stoma reversal. See at Video Abstract at http://links.lww.com/DCR/A553.

  7. Principles of a reversible programming language

    DEFF Research Database (Denmark)

    Yokoyama, Tetsuo; Axelsen, Holger Bock; Glück, Robert

    2008-01-01

    The principles of reversible programming languages are explicated and illustrated with reference to the design of a high-level imperative language, Janus. The fundamental properties for such languages include backward as well as forward determinism and reversible updates of data. The unique design...... languages, and demonstrate this for Janus. We show the practicality of the language by implementation of a reversible fast Fourier transform. Our results indicate that the reversible programming paradigm has fundamental properties that are relevant to many different areas of computer science....... features of the language include explicit post-condition assertions, direct access to an inverse semantics and the possibility of clean (i.e., garbage-free) computation of injective functions. We suggest the clean simulation of reversible Turing machines as a criterion for computing strength of reversible...

  8. ‘Picking People to Hate’: Reversible reversals in stand-up comedy

    DEFF Research Database (Denmark)

    Keisalo, Marianna Päivikki

    2017-01-01

    Generally speaking, ritual reversals mean switching to the opposite of what is considered ‘the normal order’. Such reversals can occur, for example, in terms of social hierarchies in rites of passage, in action in carnival, or in the framing of action as ritual or performance. For comedic figures...... cultural grounds and show how the study of comedic performance can offer insights into the semiotics of performance more broadly....

  9. Cu-catalyzed aerobic oxidative cyclizations of 3-N-hydroxyamino-1,2-propadienes with alcohols, thiols, and amines to form α-O-, S-, and N-substituted 4-methylquinoline derivatives.

    Science.gov (United States)

    Sharma, Pankaj; Liu, Rai-Shung

    2015-03-16

    A one-pot, two-step synthesis of α-O-, S-, and N-substituted 4-methylquinoline derivatives through Cu-catalyzed aerobic oxidations of N-hydroxyaminoallenes with alcohols, thiols, and amines is described. This reaction sequence involves an initial oxidation of N-hydroxyaminoallenes with NuH (Nu = OH, OR, NHR, and SR) to form 3-substituted 2-en-1-ones, followed by Brønsted acid catalyzed intramolecular cyclizations of the resulting products. Our mechanistic analysis suggests that the reactions proceed through a radical-type mechanism rather than a typical nitrone-intermediate route. The utility of this new Cu-catalyzed reaction is shown by its applicability to the synthesis of several 2-amino-4-methylquinoline derivatives, which are known to be key precursors to several bioactive molecules. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Periodicity and Immortality in Reversible Computing

    OpenAIRE

    Kari , Jarkko; Ollinger , Nicolas

    2008-01-01

    Additional material available on the web at http://www.lif.univ-mrs.fr/~nollinge/rec/gnirut/; We investigate the decidability of the periodicity and the immortality problems in three models of reversible computation: reversible counter machines, reversible Turing machines and reversible one-dimensional cellular automata. Immortality and periodicity are properties that describe the behavior of the model starting from arbitrary initial configurations: immortality is the property of having at le...

  11. Protein samples for NMR: expression and analysis without purification, and stabilization by covalent cyclization

    International Nuclear Information System (INIS)

    Otting, G.; Ozawa, K.; Prosselkov, P.; Williams, N.K.; Dixon, N.E.; Liepinsh, E.

    2002-01-01

    Full text: A modified cell-free in vitro expression system was established for the expression of milligram quantities of protein per mL reaction medium. Expression levels of the E coli cytoplasmic peptidyl-prolyl cis-trans isomerase, PpiB, in 0 6 mL reaction medium were sufficient for the direct recording of clean 15N-HSQC spectra without chromatographic purification or sample concentration steps, using a 600 MHz NMR spectrometer with cryoprobe. Besides providing a route to high-throughput sample preparation, in vitro expression systems are known to be highly economic in their utilization of selectively labelled ammo acids. Using dual-selective labelling with 15N- and 13C-labelled amino acids, the 15N-HSQC cross peaks of strategically selected ammo acids can readily be identified and monitored for their response to the presence of ligand molecules, again without sample purification. 2) The N-terminal domain of E coli DnaB is a protein of ca 110 residues with a structured core composed of 6 helices. Additional segments of 10 residues each at the N- and C-termini are highly mobile. Both ends are close in space and can be linked together in a covalent peptide bond using intern technology. The core structures of linear (lin-DnaB-N) and cyclized (cz-DnaB-N) protein are conserved, as evidenced by superimposable NOESY spectra and chemical shifts. The linker segment in cz-DnaB-N is mobile as shown by 1H-15N NOEs. Yet, the cyclic protein melts about 10 degrees higher than the linear version. A stabilization free energy of ca 2 kcal/mol is in agreement with predictions based on the reduced entropy in the unfolded state. Amide proton exchange rates are much slower in the cyclic protein and reveal cooperative exchange through total, global unfolding at a rate of once every 100 minutes in the linear protein

  12. How decision reversibility affects motivation.

    Science.gov (United States)

    Bullens, Lottie; van Harreveld, Frenk; Förster, Jens; Higgins, Tory E

    2014-04-01

    The present research examined how decision reversibility can affect motivation. On the basis of extant findings, it was suggested that 1 way it could affect motivation would be to strengthen different regulatory foci, with reversible decision making, compared to irreversible decision making, strengthening prevention-related motivation relatively more than promotion-related motivation. If so, then decision reversibility should have effects associated with the relative differences between prevention and promotion motivation. In 5 studies, we manipulated the reversibility of a decision and used different indicators of regulatory focus motivation to test these predictions. Specifically, Study 1 tested for differences in participants' preference for approach versus avoidance strategies toward a desired end state. In Study 2, we used speed and accuracy performance as indicators of participants' regulatory motivation, and in Study 3, we measured global versus local reaction time performance. In Study 4, we approached the research question in a different way, making use of the value-from-fit hypothesis (Higgins, 2000, 2002). We tested whether a fit between chronic regulatory focus and focus induced by the reversibility of the decision increased participants' subjective positive feelings about the decision outcome. Finally, in Study 5, we tested whether regulatory motivation, induced by decision reversibility, also influenced participants' preference in specific product features. The results generally support our hypothesis showing that, compared to irreversible decisions, reversible decisions strengthen a prevention focus more than a promotion focus. Implications for research on decision making are discussed.

  13. [Findings from Total Colonoscopy in Obstructive Colorectal Cancer Patients Who Underwent Stent Placement as a Bridge to Surgery(BTS)].

    Science.gov (United States)

    Maruo, Hirotoshi; Tsuyuki, Hajime; Kojima, Tadahiro; Koreyasu, Ryohei; Nakamura, Koichi; Higashi, Yukihiro; Shoji, Tsuyoshi; Yamazaki, Masanori; Nishiyama, Raisuke; Ito, Tatsuhiro; Koike, Kota; Ikeda, Takashi; Takayanagi, Yasuhiro; Kubota, Hiroyuki

    2017-11-01

    We clinically investigated 34 patients with obstructive colorectal cancer who underwent placement of a colonic stent as a bridge to surgery(BTS), focusing on endoscopic findings after stent placement.Twenty -nine patients(85.3%)underwent colonoscopy after stent placement, and the entire large intestine could be observed in 28(96.6%).Coexisting lesions were observed in 22(78.6%)of these 28 patients.The lesions comprised adenomatous polyps in 17 patients(60.7%), synchronous colon cancers in 5 patients(17.9%), and obstructive colitis in 3 patients(10.7%), with some overlapping cases.All patients with multiple cancers underwent one-stage surgery, and all lesions were excised at the same time.Colonoscopy after colonic stent placement is important for preoperative diagnosis of coexisting lesions and planning the extent of resection. These considerations support the utility of colonic stenting for BTS.

  14. Posterior Reversible Encephalopathy Syndrome in Pediatric Cancer: Clinical and Radiologic Findings

    Directory of Open Access Journals (Sweden)

    Saadiya Javed Khan

    2017-12-01

    Full Text Available Purpose: Posterior reversible encephalopathy syndrome (PRES is associated with a range of medical conditions and medications. In this retrospective analysis, we present 19 pediatric patients with PRES who had undergone chemotherapy. Methods: We identified four female and 15 male patients diagnosed with PRES on the basis of clinical and radiologic features. Patient charts were reviewed from January 2013 to June 2016 after authorization from the institutional review board. Results: The average age of patients with PRES was 7 years. Primary diagnoses were non-Hodgkin lymphoma (n = 9, acute pre–B-cell leukemia (n = 5, relapsed pre–B-cell leukemia (n = 2, Hodgkin lymphoma (n = 2, and Ewing sarcoma (n = 1. PRES occurred during induction chemotherapy in 12 patients. Sixteen patients had hypertension when they developed PRES. Most of these patients (n = 13 were receiving corticosteroids on diagnosis of PRES. Common clinical features were hypertension, seizures, and altered mental status. With the exclusion of three patients, all others required antiepileptic therapy. Ten of these patients underwent additional magnetic resonance imaging. Ten patients are still alive. Conclusion: In patients who presented to our center with signs and symptoms of hypertension, seizures, visual loss, or altered mental status, PRES was mostly seen in those who were undergoing systemic and intrathecal chemotherapy. Approximately 40% of the patients had reversal of clinical and radiologic findings. Antiepileptic medications were discontinued after being seizure free for approximately 6 months.

  15. MODELS OF PROJECT REVERSE ENGINEERING

    Directory of Open Access Journals (Sweden)

    Віктор Володимирович ІВАНОВ

    2017-03-01

    Full Text Available Reverse engineering decided important scientific and technical problems of increasing the cost of the existing technical product by transforming it into a product with other features or design. Search ideas of the new application of existing products on the base of heuristic analysis were created. The concept of reverse engineering and its division into three types: conceptual, aggregate and complete was expanded. The use of heuristic methods for reverse engineering concept was showed. The modification model of Reverse engineering based on the model of РМВОК was developed. Our model includes two new phases: identification and transformation. At the identification phase, technical control is made. At the transformation phase, search heuristic idea of the new applied existing technical product was made. The model of execution phase that included heuristic methods, metrological equipment, and CAD/CAM/CAE program complex was created. The model that connected economic indicators of reverse engineering project was developed.

  16. Garbage collection for reversible functional languages

    DEFF Research Database (Denmark)

    Mogensen, Torben Ægidius

    2015-01-01

    Reversible languages are programming languages where all programs can run both forwards and backwards. Reversible functional languages have been proposed that use symmetric pattern matching and data construction. To be reversible, these languages require linearity: Every variable must be used...

  17. Melanome Therapy with Rhenium Cyclized Alpha Melanocyte Stimulating Hormone Peptide Analogs. Final report

    International Nuclear Information System (INIS)

    Quinn, Thomas P.

    2005-01-01

    Malignant melanoma is the 6th most commonly diagnosed cancer with increasing incidence in the United States. It is estimated that 54,200 cases of malignant melanoma will be newly diagnosed and 7,600 cases of death will occur in the United States in the year 2003 (1). At the present time, more than 1.3% of Americans will develop malignant melanoma during their lifetime (2). The average survival for patients with metastatic melanoma is about 6-9 months (3). Moreover, metastatic melanoma deposits are resistant to conventional chemotherapy and external beam radiation therapy (3). Systematic chemotherapy is the primary therapeutic approach to treat patients with metastatic melanoma. Dacarbazine is the only single chemotherapy agent approved by FDA for metastatic melanoma treatment (5). However, the response rate to Dacarbazine is only approximately 20% (6). Therefore, there is a great need to develop novel treatment approaches for metastatic melanoma. The global goal of this research program is the rational design, characterization and validation of melanoma imaging and therapeutic radiopharmaceuticals. Significant progress has been made in the design and characterization of metal-cyclized radiolabeled alpha-melanocyte stimulating hormone peptides. Therapy studies with 188 Re-CCMSH demonstrated the therapeutic efficacy of the receptor-targeted treatment in murine and human melanoma bearing mice (previous progress report). Dosimetry calculations, based on biodistribution data, indicated that a significant dose was delivered to the tumor. However, 188 Re is a very energetic beta-particle emitter. The longer-range beta-particles theoretically would be better for larger tumors. In the treatment of melanoma, the larger primary tumor is usually surgically removed leaving metastatic disease as the focus of targeted radiotherapy. Isotopes with lower beta-energies and/or shorter particle lengths should be better suited for targeting metastases. The 177 Lu-DOTA-Re(Arg11)CCMSH and

  18. END-OF-USE PRODUCTS IN REVERSE LOGISTICS

    OpenAIRE

    Marta Starostka-Patyk

    2007-01-01

    Reverse logistics is a very useful tool for enterprises which have to deal with end-of-use products. Forward logistics is not able to manage them, because they show up on the beginning of reverse supply chain. That is the reason for growing importance of reverse flows. Reverse logistics is quite new logistics system. This paper presents the idea of reverse logistics and end-of-use products problems.

  19. Reversal of subtidal dune asymmetries caused by seasonally reversing wind-driven currents in Torres Strait, northeastern Australia

    Science.gov (United States)

    Harris, Peter T.

    1991-07-01

    Large subtidal sand dunes (sandwaves) located in Adolphus Channel, Torres Strait, have been observed to reverse their asymmetric orientation between September-February. This has been attributed to a reversal in wind-driven currents, which flow westward during the SE trade season (April-November) and eastwards during the NW monsoon season [December-March: HARRIS (1989) Continental Shelf Research, 9, 981-1002]. Observations in September 1988 and February 1989 from another area of dunes in Torres Strait corroborate this asymmetry reversal pattern. The results indicate that such reversals may be common in Torres Strait and in other areas where subtidal bedforms are subject to modification by superimposed, seasonally reversing, wind-driven currents.

  20. Magnetic reversals from planetary dynamo waves.

    Science.gov (United States)

    Sheyko, Andrey; Finlay, Christopher C; Jackson, Andrew

    2016-11-24

    A striking feature of many natural dynamos is their ability to undergo polarity reversals. The best documented example is Earth's magnetic field, which has reversed hundreds of times during its history. The origin of geomagnetic polarity reversals lies in a magnetohydrodynamic process that takes place in Earth's core, but the precise mechanism is debated. The majority of numerical geodynamo simulations that exhibit reversals operate in a regime in which the viscosity of the fluid remains important, and in which the dynamo mechanism primarily involves stretching and twisting of field lines by columnar convection. Here we present an example of another class of reversing-geodynamo model, which operates in a regime of comparatively low viscosity and high magnetic diffusivity. This class does not fit into the paradigm of reversal regimes that are dictated by the value of the local Rossby number (the ratio of advection to Coriolis force). Instead, stretching of the magnetic field by a strong shear in the east-west flow near the imaginary cylinder just touching the inner core and parallel to the axis of rotation is crucial to the reversal mechanism in our models, which involves a process akin to kinematic dynamo waves. Because our results are relevant in a regime of low viscosity and high magnetic diffusivity, and with geophysically appropriate boundary conditions, this form of dynamo wave may also be involved in geomagnetic reversals.

  1. Multiple reversal olfactory learning in honeybees

    Directory of Open Access Journals (Sweden)

    Theo Mota

    2010-07-01

    Full Text Available In multiple reversal learning, animals trained to discriminate a reinforced from a non-reinforced stimulus are subjected to various, successive reversals of stimulus contingencies (e.g. A+ vs. B-, A- vs. B+, A+ vs. B-. This protocol is useful to determine whether or not animals learn to learn and solve successive discriminations faster (or with fewer errors with increasing reversal experience. Here we used the olfactory conditioning of proboscis extension reflex to study how honeybees Apis mellifera perform in a multiple reversal task. Our experiment contemplated four consecutive differential conditioning phases involving the same odors (A+ vs. B- to A- vs. B+ to A+ vs. B- to A- vs. B+. We show that bees in which the weight of reinforced or non-reinforced stimuli was similar mastered the multiple olfactory reversals. Bees which failed the task exhibited asymmetric responses to reinforced and non-reinforced stimuli, thus being unable to rapidly reverse stimulus contingencies. Efficient reversers did not improve their successive discriminations but rather tended to generalize their choice to both odors at the end of conditioning. As a consequence, both discrimination and reversal efficiency decreasedalong experimental phases. This result invalidates a learning-to-learn effect and indicates that bees do not only respond to the actual stimulus contingencies but rather combine these with an average of past experiences with the same stimuli.  

  2. Microdose flare-up vs. flexible-multidose GnRH antagonist protocols for poor responder patients who underwent ICSI.

    Science.gov (United States)

    Esinler, I

    2014-01-01

    To compare the performance of microdose flare-up (MF) and flexible-multidose gonadotropin-releasing hormone (GnRH) antagonist protocols in poor responder patients who underwent intracytoplasmic sperm injection (ICSI). One hundred and 12 consecutive patients (217 cycles) suspected to have poor ovarian response were enrolled. Group 1 (MF GnRH agonist group) constituted 64 patients (135 cycles) who underwent MF GnRH agonist protocol. Group 2 (flexible-multidose GnRH antagonist group) constituted 48 patients (82 cycles) who underwent flexible-multidose GnRH antagonist protocol. The duration of stimulation (d) (11.5 +/- 2.1 vs. 10.4 +/- 2.7, p or = seven blastomeres and < 10% fragmentation at day 3 (35.9% vs. 65.1%, p < 0.05) were significantly lower in Group 1 when compared to Group 2. The number of embryos transferred (2.2 +/- 1.3 vs. 2.4 +/- 0.9), the clinical pregnancy per embryo transfer (16.3% vs. 25.8%), and the implantation rate (8.6% vs. 12.2%) were comparable between groups. Although the flexible-multidose GnRH antagonist protocol produced better oocyte and embryo parameters, the clinical pregnancy rate and the implantation rates were comparable between the flexible-multidose GnRH antagonist and MF protocols in poor responder patients.

  3. Reversibility: An Engineer's Point of View

    Energy Technology Data Exchange (ETDEWEB)

    Berest, Pierre [LMS, ecole Polytechnique (France)

    2012-07-01

    Reversibility is the most consistent option in a democratic country. However reversibility may also have several drawbacks which must be identified and mitigated. Reversibility of a geological repository is a relatively new idea in France. The 1991 law dedicated to nuclear waste management considered reversibility as a possible option. Fifteen years later, the 2006 law mandated that a deep repository must be reversible and that the exact content of this notion should be defined by a new law to be discussed by the Parliament in 2015. Reversibility was not a concern put forward by engineers. It clearly originated from a societal demand sponsored and formulated by the Parliament. Since 1991, the exact meaning of this mandate progressively became more precise. In the early days, reversibility meant the technical and financial capability to retrieve the wastes from the repository, at least for some period of time after being emplaced. Progressively, a broader definition, suggested by Andra, was accepted: reversibility also means that a disposal facility should be operated in such a way that a stepwise decision-making process is possible. At each step, society must be able to decide to proceed to the next step, to pause or to reverse a step. Several benefits can be expected from a reversible repository. Some technical safety concerns may be only recognised after waste emplacement. Radioactive wastes may become a resource whose recoverability is desirable. Regulations may change, alternative waste treatment or better disposal techniques may be developed, or the need to modify a component of the facility may arise. Looking back at how chemical or domestic wastes were managed some 50 years ago easily underscores that it is not unreasonable to hope for significant advances in the future. For scientists and engineers, reversibility proves to have several other merits. To design and build a good repository, time is needed. The operator of a mine or of an oil field knows that

  4. Reversible and non-reversible enlargement of cerebral spinal fluid spaces in anorexia nervosa

    International Nuclear Information System (INIS)

    Artmann, H.; Grau, H.; Adelmann, M.; Schleiffer, R.

    1985-01-01

    Brain CT studies of 35 patients with anoxia nervosa confirmed the observations of other authors: cerebral dystrophic changes correlate with weight loss and the reversibility of these changes also correlates with the normalization of body weight. Other corroborated facts are: the most numerous and most pronounced enlargements are of the cortical sulci and the interhemispheric fissure, moderate widening affects the ventricles and the rarest and most insignificant changes are those of the cerebellum. The reversibility of the changes showed a parallel to the extent of the changes themselves and to the duration of improvement of the body weight. The reversibility of the enlargement of the cortical sulci and of the distances between the frontal horns of the lateral ventricles was more often significant than that of the abnormal measurements of the cella media. This difference is based on minimal early acquired brain damage which occurs in 60% of our patients. This high incidence of early acquired minimal brain disease in patients with anorexia nervosa is here discussed as a nonspecific predisposing factor. Although there is no exact explanation of the etiology of the reversible enlargement of cerenral spinal fluid (CSF) spaces in anorexia nervosa, the changes resemble those in alcoholics. The mechanisms of brain changes in alcoholism, as shown experimentally, seem to us to throw light on the probable mechanism of reversible dystrophic brain changes in anorexia nervosa. (orig.)

  5. Reversible and non-reversible enlargement of cerebral spinal fluid spaces in anorexia nervosa

    Energy Technology Data Exchange (ETDEWEB)

    Artmann, H.; Grau, H.; Adelmann, M.; Schleiffer, R.

    1985-07-01

    Brain CT studies of 35 patients with anoxia nervosa confirmed the observations of other authors: cerebral dystrophic changes correlate with weight loss and the reversibility of these changes also correlates with the normalization of body weight. Other corroborated facts are: the most numerous and most pronounced enlargements are of the cortical sulci and the interhemispheric fissure, moderate widening affects the ventricles and the rarest and most insignificant changes are those of the cerebellum. The reversibility of the changes showed a parallel to the extent of the changes themselves and to the duration of improvement of the body weight. The reversibility of the enlargement of the cortical sulci and of the distances between the frontal horns of the lateral ventricles was more often significant than that of the abnormal measurements of the cella media. This difference is based on minimal early acquired brain damage which occurs in 60% of our patients. This high incidence of early acquired minimal brain disease in patients with anorexia nervosa is here discussed as a nonspecific predisposing factor. Although there is no exact explanation of the etiology of the reversible enlargement of cerenral spinal fluid (CSF) spaces in anorexia nervosa, the changes resemble those in alcoholics. The mechanisms of brain changes in alcoholism, as shown experimentally, seem to us to throw light on the probable mechanism of reversible dystrophic brain changes in anorexia nervosa.

  6. Reversal agents in anaesthesia and critical care

    Directory of Open Access Journals (Sweden)

    Nibedita Pani

    2015-01-01

    Full Text Available Despite the advent of short and ultra-short acting drugs, an in-depth knowledge of the reversal agents used is a necessity for any anaesthesiologist. Reversal agents are defined as any drug used to reverse the effects of anaesthetics, narcotics or potentially toxic agents. The controversy on the routine reversal of neuromuscular blockade still exists. The advent of newer reversal agents like sugammadex have made the use of steroidal neuromuscular blockers like rocuronium feasible in rapid sequence induction situations. We made a review of the older reversal agents and those still under investigation for drugs that are regularly used in our anaesthesia practice.

  7. The misconception of mean-reversion

    International Nuclear Information System (INIS)

    Eliazar, Iddo I; Cohen, Morrel H

    2012-01-01

    The notion of random motion in a potential well is elemental in the physical sciences and beyond. Quantitatively, this notion is described by reverting diffusions—asymptotically stationary diffusion processes which are simultaneously (i) driven toward a reversion level by a deterministic force, and (ii) perturbed off the reversion level by a random white noise. The archetypal example of reverting diffusions is the Ornstein–Uhlenbeck process, which is mean-reverting. In this paper we analyze reverting diffusions and establish that: (i) if the magnitude of the perturbing noise is constant then the diffusion's stationary density is unimodal and the diffusion is mode-reverting; (ii) if the magnitude of the perturbing noise is non-constant then, in general, neither is the diffusion's stationary density unimodal, nor is the diffusion mode-reverting. In the latter case we further establish a result asserting when unimodality and mode-reversion do hold. In particular, we demonstrate that the notion of mean-reversion, which is fundamental in economics and finance, is a misconception—as mean-reversion is an exception rather than the norm. (fast track communication)

  8. Parkinson’s disease managing reversible neurodegeneration

    Science.gov (United States)

    Hinz, Marty; Stein, Alvin; Cole, Ted; McDougall, Beth; Westaway, Mark

    2016-01-01

    Traditionally, the Parkinson’s disease (PD) symptom course has been classified as an irreversible progressive neurodegenerative disease. This paper documents 29 PD and treatment-induced systemic depletion etiologies which cause and/or exacerbate the seven novel primary relative nutritional deficiencies associated with PD. These reversible relative nutritional deficiencies (RNDs) may facilitate and accelerate irreversible progressive neurodegeneration, while other reversible RNDs may induce previously undocumented reversible pseudo-neurodegeneration that is hiding in plain sight since the symptoms are identical to the symptoms being experienced by the PD patient. Documented herein is a novel nutritional approach for reversible processes management which may slow or halt irreversible progressive neurodegenerative disease and correct reversible RNDs whose symptoms are identical to the patient’s PD symptoms. PMID:27103805

  9. Reversible machine code and its abstract processor architecture

    DEFF Research Database (Denmark)

    Axelsen, Holger Bock; Glück, Robert; Yokoyama, Tetsuo

    2007-01-01

    A reversible abstract machine architecture and its reversible machine code are presented and formalized. For machine code to be reversible, both the underlying control logic and each instruction must be reversible. A general class of machine instruction sets was proven to be reversible, building...

  10. Solid-Phase Reactions of Iminium Ions: Cyclized Peptide Derivatives

    DEFF Research Database (Denmark)

    Wang, Yuanyuan

    formation of N,N’-aminals by nucleophilic attack of the peptide backbone is reversible under strongly acidic conditions and the N,N’-aminal is likely to be the kinetic product of many INCIC reactions. In addition, the N,N’-aminals are stable in the absence of acid but could be converted to the THIQ...... derivatives in solution phase under acid conditions in the presence of an active C-nucleophile in the side chain. The high yielding nature of the aminal formation is confirmed by solution phase synthesis. The introduced azide and alkyne residues in the side chain of N,N’-aminal products were further......BB may undergo auto-oxidation to quinazoline-2,4-diones in the absence of a suitable nucleophile on the side chain or backbone of the peptide (Chapter 4). The structure is confirmed by comparison with products obtained from solution-phase synthesis under the same conditions, one of which was confirmed...

  11. A Typology of Reverse Innovation

    DEFF Research Database (Denmark)

    von Zedtwitz, Max; Corsi, Simone; Søberg, Peder Veng

    2015-01-01

    secondary market introduction, this study expands the espoused definition of reverse innovation beyond its market-introduction focus with reversals in the flow of innovation in the ideation and product development phases. Recognizing that each phase can take place in different geographical locations...... taking place in an emerging country. This analytical framework allows recasting of current research at the intersection between innovation and international business. Of the 10 reverse innovation flows, six are new and have not been covered in the literature to date. The study addresses questions......’s portfolio of global innovation competence and capability. The implications for management are concerned with internal and external resistance to reverse innovation. Most significantly, while greater recognition and power of innovation in formerly subordinate organizational units is inconvenient to some...

  12. Diversity-Oriented Syntheses by Combining CuAAC and Stereoselective INCIC Reactions with Peptides

    DEFF Research Database (Denmark)

    Wang, Yuanyuan; Madsen, Anders; Diness, Frederik

    2017-01-01

    Cascade reactions proceeding through peptide-derived N-carbamoyl iminium ions are reported. Two new reactions of N-carbamoyl iminium ions are described, including a stereoselective double cyclization generating N,N′-aminals and an acid-promoted auto-oxidation. Mechanistic investigations revealed...... that the N,N′-aminal formation is reversible under strongly acidic conditions. Both of these new reactions proved to be completely orthogonal to subsequent CuAAC chemistry. The reactions were performed in solution and on solid support. The robustness and high stereoselectivity of the methodology holds great...

  13. Elements of a Reversible Object-Oriented Language

    DEFF Research Database (Denmark)

    Schultz, Ulrik Pagh; Axelsen, Holger Bock

    2016-01-01

    This paper presents initial ideas for the design and implementation of a reversible object-oriented language based on extending Janus with object-oriented concepts such as classes that encapsulate behavior and state, inheritance, virtual dispatching, as well as constructors. We show that virtual...... dispatching is a reversible decision mechanism easily translatable to a standard reversible programming model such as Janus, and we argue that reversible management of state can be accomplished using reversible constructors. The language is implemented in terms of translation to standard Janus programs....

  14. Drift reversal capability in helical systems

    International Nuclear Information System (INIS)

    Yokoyama, M.; Itoh, K.; Okamura, S.

    2002-10-01

    The maximum-J (J is the second adiabatic invariant) capability, i.e., the drift reversal capability, is examined in quasi-axisymmetric (QAS) stellarators and quasi-poloidally symmetric (QPS) stellarators as a possible mechanism for turbulent transport suppression. Due to the existence of non-axisymmetry of the magnetic field strength in QAS configurations, a local maximum of J is created to cause the drift reversal. The increase of magnetic shear in finite beta equilibria also has favorable effect in realizing the drift reversal. The radial variation of the uniform magnetic field component plays a crucial role for the drift reversal in a QPS configuration. Thus, the drift reversal capability and its external controllability are demonstrated for QAS and QPS stellarators, by which the impact of magnetic configuration on turbulent transport can be studied in experiments. (author)

  15. Drift reversal capability in helical systems

    International Nuclear Information System (INIS)

    Yokoyama, M.; Itoh, K.; Okamura, S.; Matsuoka, K.; Nakajima, N.; Itoh, S.-I.; Neilson, G.H.; Zarnstorff, M.C.; Rewoldt, G.

    2003-01-01

    The maximum-J (J is the second adiabatic invariant) capability, i.e., the drift reversal capability, is examined in quasi-axisymmetric (QAS) stellarators and quasi-poloidally symmetric (QPS) stellarators as a possible mechanism for turbulent transport suppression. Due to the existence of non-axisymmetry of the magnetic field strength in QAS configurations, a local maximum of J is created to cause the drift reversal. The increase of magnetic shear in finite beta equilibria also has favorable effect in realizing the drift reversal. The radial variation of the uniform magnetic field component plays a crucial role for the drift reversal in a QPS configuration. Thus, the drift reversal capability and its external controllability are demonstrated for QAS and QPS stellarators, by which the impact of magnetic configuration on turbulent transport can be studied in experiments. (author)

  16. Kinetic Line Voronoi Operations and Their Reversibility

    DEFF Research Database (Denmark)

    Mioc, Darka; Anton, François; Gold, Christopher

    2010-01-01

    In Geographic Information Systems the reversibility of map update operations has not been explored yet. In this paper we are using the Voronoi based Quad-edge data structure to define reversible map update operations. The reversibility of the map operations has been formalised at the lowest level...... mechanisms and dynamic map visualisations. In order to use the reversibility within the kinetic Voronoi diagram of points and open oriented line segments, we need to assure that reversing the map commands will produce exactly the changes in the map equivalent to the previous map states. To prove...... that reversing the map update operations produces the exact reverse changes, we show an isomorphism between the set of complex operations on the kinetic Voronoi diagram of points and open oriented line segments and the sets of numbers of new / deleted Voronoi regions induced by these operations, and its...

  17. Prediction of Pathological Complete Response Using Endoscopic Findings and Outcomes of Patients Who Underwent Watchful Waiting After Chemoradiotherapy for Rectal Cancer.

    Science.gov (United States)

    Kawai, Kazushige; Ishihara, Soichiro; Nozawa, Hiroaki; Hata, Keisuke; Kiyomatsu, Tomomichi; Morikawa, Teppei; Fukayama, Masashi; Watanabe, Toshiaki

    2017-04-01

    Nonoperative management for patients with rectal cancer who have achieved a clinical complete response after chemoradiotherapy is becoming increasingly important in recent years. However, the definition of and modality used for patients with clinical complete response differ greatly between institutions, and the role of endoscopic assessment as a nonoperative approach has not been fully investigated. This study aimed to investigate the ability of endoscopic assessments to predict pathological regression of rectal cancer after chemoradiotherapy and the applicability of these assessments for the watchful waiting approach. This was a retrospective comparative study. This study was conducted at a single referral hospital. A total of 198 patients with rectal cancer underwent preoperative endoscopic assessments after chemoradiotherapy. Of them, 186 patients underwent radical surgery with lymph node dissection. The histopathological findings of resected tissues were compared with the preoperative endoscopic findings. Twelve patients refused radical surgery and chose watchful waiting; their outcomes were compared with the outcomes of patients who underwent radical surgery. The endoscopic criteria correlated well with tumor regression grading. The sensitivity and specificity for a pathological complete response were 65.0% to 87.1% and 39.1% to 78.3%. However, endoscopic assessment could not fully discriminate pathological complete responses, and the outcomes of patients who underwent watchful waiting were considerably poorer than the patients who underwent radical surgery. Eventually, 41.7% of the patients who underwent watchful waiting experienced uncontrollable local failure, and many of these occurrences were observed more than 3 years after chemoradiotherapy. The number of the patients treated with the watchful waiting strategy was limited, and the selection was not randomized. Although endoscopic assessment after chemoradiotherapy correlated with pathological response

  18. Atrioventricular Pacemaker Lead Reversal

    Directory of Open Access Journals (Sweden)

    Mehmet K Aktas, MD

    2007-01-01

    Full Text Available During cardiac surgery temporary epicardial atrial and ventricular leads are placed in case cardiac pacing is required postoperatively. We present the first reported series of patients with reversal of atrioventricular electrodes in the temporary pacemaker without any consequent deleterious hemodynamic effect. We review the electrocardiographic findings and discuss the findings that lead to the discovery of atrioventricular lead reversal.

  19. Safety and Tolerability of Transitioning from Cangrelor to Ticagrelor in Patients Who Underwent Percutaneous Coronary Intervention.

    Science.gov (United States)

    Badreldin, Hisham A; Carter, Danielle; Cook, Bryan M; Qamar, Arman; Vaduganathan, Muthiah; Bhatt, Deepak L

    2017-08-01

    The 3 phase 3 CHAMPION (Cangrelor vs Standard Therapy to Achieve Optimal Management of Platelet Inhibition) trials collectively demonstrated the safety of transitioning from cangrelor, a potent, parenteral rapidly-acting P2Y 12 inhibitor, to clopidogrel in patients who underwent percutaneous coronary intervention (PCI). However, variation in timing of therapy, site-specific binding, and drug half-lives may theoretically complicate switching to other oral P2Y 12 inhibitors. Since regulatory approval, limited data are available regarding the "real-world" safety and tolerability of transitioning to these more potent oral P2Y 12 antagonists. From November 2015 to January 2017, we evaluated the clinical profiles and efficacy and safety outcomes in cangrelor-treated patients who underwent PCI transitioned to clopidogrel (n = 42) or ticagrelor (n = 82) at a large, tertiary care center. Most patients receiving cangrelor underwent PCI with a drug-eluting stent for acute coronary syndrome via a radial approach in the background of unfractionated heparin. Stent thrombosis within 48 hours was rare and occurred in 1 patient treated with ticagrelor. Global Use of Strategies to Open Occluded Coronary Arteries-defined bleeding occurred in 20% of patients switched to ticagrelor and 29% of patients switched to clopidogrel, but none were severe or life-threatening. In conclusion, rates of stent thrombosis and severe/life-threatening bleeding were low and comparable with those identified in the CHAMPION program, despite use of more potent oral P2Y 12 inhibition. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Reversal modes in asymmetric Ni nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Leighton, B.; Pereira, A. [Departamento de Fisica, Universidad de Santiago de Chile (USACH), Avda. Ecuador 3493, 917-0124 Santiago (Chile); Escrig, J., E-mail: jescrigm@gmail.com [Departamento de Fisica, Universidad de Santiago de Chile (USACH), Avda. Ecuador 3493, 917-0124 Santiago (Chile); Center for the Development of Nanoscience and Nanotechnology (CEDENNA), Avda. Ecuador 3493, 917-0124 Santiago (Chile)

    2012-11-15

    We have investigated the evolution of the magnetization reversal mechanism in asymmetric Ni nanowires as a function of their geometry. Circular nanowires are found to reverse their magnetization by the propagation of a vortex domain wall, while in very asymmetric nanowires the reversal is driven by the propagation of a transverse domain wall. The effect of shape asymmetry of the wire on coercivity and remanence is also studied. Angular dependence of the remanence and coercivity is also addressed. Tailoring the magnetization reversal mechanism in asymmetric nanowires can be useful for magnetic logic and race-track memory, both of which are based on the displacement of magnetic domain walls. Finally, an alternative method to detect the presence of magnetic drops is proposed. - Highlights: Black-Right-Pointing-Pointer Asymmetry strongly modifies the magnetic behavior of a wire. Black-Right-Pointing-Pointer Very asymmetric nanowires reverse their magnetization by a transverse domain wall. Black-Right-Pointing-Pointer An alternative method to detect the presence of magnetic drops is proposed. Black-Right-Pointing-Pointer Tailoring the reversal mode in asymmetric nanowires can be useful for potential applications.

  1. Introduction to time reversal theory

    International Nuclear Information System (INIS)

    Henley, E.M.

    1987-01-01

    Theory and reaction mechanisms relevant to time reversal invariance are reviewed. Consequences of time reversal invariance are presented under the headings of CP tests, electromagnetic moments, weak emissions or absorptions, and scattering reactions. 8 refs., 4 figs

  2. Vasectomy reversal: a clinical update

    Directory of Open Access Journals (Sweden)

    Abhishek P Patel

    2016-01-01

    Full Text Available Vasectomy is a safe and effective method of contraception used by 42-60 million men worldwide. Approximately 3%-6% of men opt for a vasectomy reversal due to the death of a child or divorce and remarriage, change in financial situation, desire for more children within the same marriage, or to alleviate the dreaded postvasectomy pain syndrome. Unlike vasectomy, vasectomy reversal is a much more technically challenging procedure that is performed only by a minority of urologists and places a larger financial strain on the patient since it is usually not covered by insurance. Interest in this procedure has increased since the operating microscope became available in the 1970s, which consequently led to improved patency and pregnancy rates following the procedure. In this clinical update, we discuss patient evaluation, variables that may influence reversal success rates, factors to consider in choosing to perform vasovasostomy versus vasoepididymostomy, and the usefulness of vasectomy reversal to alleviate postvasectomy pain syndrome. We also review the use of robotics for vasectomy reversal and other novel techniques and instrumentation that have emerged in recent years to aid in the success of this surgery.

  3. Reversible deep storage: reversibility options for storage in deep geological formations

    International Nuclear Information System (INIS)

    2009-01-01

    This report describes the definition approach to reversibility conditions, presents the main characteristics of high-activity and intermediate-activity long-lived wastes, describes the storage in deep geological formations (safety functions, general description of the storage centre), discusses the design options for the different types of wastes (container, storage module, handling processes, phenomenological analysis, monitoring arrangements) and the decision process in support reversibility (steering of the storage process, progressive development and step-by-step closing), and reports and discusses the researches concerning the memory of the storage site

  4. Chemical reactions in reverse micelle systems

    Science.gov (United States)

    Matson, Dean W.; Fulton, John L.; Smith, Richard D.; Consani, Keith A.

    1993-08-24

    This invention is directed to conducting chemical reactions in reverse micelle or microemulsion systems comprising a substantially discontinuous phase including a polar fluid, typically an aqueous fluid, and a microemulsion promoter, typically a surfactant, for facilitating the formation of reverse micelles in the system. The system further includes a substantially continuous phase including a non-polar or low-polarity fluid material which is a gas under standard temperature and pressure and has a critical density, and which is generally a water-insoluble fluid in a near critical or supercritical state. Thus, the microemulsion system is maintained at a pressure and temperature such that the density of the non-polar or low-polarity fluid exceeds the critical density thereof. The method of carrying out chemical reactions generally comprises forming a first reverse micelle system including an aqueous fluid including reverse micelles in a water-insoluble fluid in the supercritical state. Then, a first reactant is introduced into the first reverse micelle system, and a chemical reaction is carried out with the first reactant to form a reaction product. In general, the first reactant can be incorporated into, and the product formed in, the reverse micelles. A second reactant can also be incorporated in the first reverse micelle system which is capable of reacting with the first reactant to form a product.

  5. Status of time reversal invariance

    International Nuclear Information System (INIS)

    Henley, E.M.

    1989-01-01

    Time Reversal Invariance is introduced, and theories for its violation are reviewed. The present experimental and theoretical status of Time Reversal Invariance and tests thereof will be presented. Possible future tests will be discussed. 30 refs., 2 figs., 1 tab

  6. Cigarette smoking and schizophrenia independently and reversibly altered intrinsic brain activity.

    Science.gov (United States)

    Liu, Huan; Luo, Qi; Du, Wanyi; Li, Xingbao; Zhang, Zhiwei; Yu, Renqiang; Chen, Xiaolu; Meng, Huaqing; Du, Lian

    2018-01-03

    Schizophrenia patients are at high risk for cigarette smoking, but the neurobiological mechanisms of this comorbid association are relatively unknown. Long-term nicotine intake may impact brain that are independently and additively associated with schizophrenia. We investigated whether altered intrinsic brain activity (iBA) related to schizophrenia pathology is also associated with nicotine addiction. Forty-two schizophrenia patients (21 smokers and 21 nonsmokers) and 21 sex- and age-matched healthy nonsmokers underwent task-free functional MRI. Whole brain iBA was measured by the amplitude of spontaneous low frequency fluctuation. Furthermore, correlation analyses between iBA, symptom severity and nicotine addiction severity were performed. We found that prefrontal cortex, right caudate, and right postcentral gyrus were related to both disease and nicotine addiction effects. More importantly, schizophrenia smokers, compared to schizophrenia nonsmokers showed reversed iBA in the above brain regions. In addition, schizophrenia smokers, relative to nonsmokers, altered iBA in the left striatal and motor cortices. The iBA of the right caudate was negatively correlated with symptom severity. The iBA of the right postcentral gyrus negatively correlated with nicotine addiction severity. The striatal and motor cortices could potentially increase the vulnerability of smoking in schizophrenia. More importantly, smoking reversed iBA in the right striatal and prefrontal cortices, consistent with the self-medication theory in schizophrenia. Smoking altered left striatal and motor cortices activity, suggesting that the nicotine addiction effect was independent of disease. These results provide a local property of intrinsic brain activity mechanism that contributes to cigarette smoking and schizophrenia.

  7. Towards a reversible functional language

    DEFF Research Database (Denmark)

    Yokoyama, Tetsuo; Axelsen, Holger Bock; Glück, Robert

    2012-01-01

    /equality operator also simplifies inverse computation and program inversion. We discuss the advantages of a reversible functional language using example programs, including run-length encoding. Program inversion is seen to be as lightweight as for imperative reversible languages and realized by recursive descent...

  8. How decision reversibility affects motivation

    NARCIS (Netherlands)

    Bullens, L.; van Harreveld, F.; Förster, J.; Higgins, T.E.

    2014-01-01

    The present research examined how decision reversibility can affect motivation. On the basis of extant findings, it was suggested that 1 way it could affect motivation would be to strengthen different regulatory foci, with reversible decision making, compared to irreversible decision making,

  9. Reversible networks in supramolecular polymers

    NARCIS (Netherlands)

    Havermans - van Beek, D.J.M.

    2007-01-01

    Non–covalent interactions between low molecular weight polymers form the basis of supramolecular polymers. The material properties of such polymers are determined by the strength and lifetime of the non–covalent reversible interactions. Due to the reversibility of the interactions between the low

  10. Sex reversal in vertebrates

    OpenAIRE

    2016-01-01

    This special topic issue of Sexual Development gives an overview of sex reversal in vertebrates, from fishes naturally changing their sex, to rodents escaping the mammalian SRY-determining system. It offers eight up-to-date reviews on specific subjects in sex reversal, considering fishes, amphibians, reptiles, birds, marsupials, and placental mammals, including humans. The broad scope of represented animals makes this ideal for students and researchers, especially those interested in the...

  11. Enzymatic reactions in reversed micelles

    NARCIS (Netherlands)

    Hilhorst, M.H.

    1984-01-01

    It has been recognised that enzymes in reversed micelles have potential for application in chemical synthesis. Before these expectations will be realised many problems must be overcome. This thesis deals with some of them.
    In Chapter 1 the present knowledge about reversed micelles and

  12. Reversible arithmetic logic unit for quantum arithmetic

    DEFF Research Database (Denmark)

    Thomsen, Michael Kirkedal; Glück, Robert; Axelsen, Holger Bock

    2010-01-01

    This communication presents the complete design of a reversible arithmetic logic unit (ALU) that can be part of a programmable reversible computing device such as a quantum computer. The presented ALU is garbage free and uses reversible updates to combine the standard reversible arithmetic...... and logical operations in one unit. Combined with a suitable control unit, the ALU permits the construction of an r-Turing complete computing device. The garbage-free ALU developed in this communication requires only 6n elementary reversible gates for five basic arithmetic-logical operations on two n......-bit operands and does not use ancillae. This remarkable low resource consumption was achieved by generalizing the V-shape design first introduced for quantum ripple-carry adders and nesting multiple V-shapes in a novel integrated design. This communication shows that the realization of an efficient reversible...

  13. Reverse engineering for quality systems

    International Nuclear Information System (INIS)

    Nolan, A.J.

    1995-01-01

    When the age of software engineering began, many companies were faced with a problem of how to support the older, pre-software-engineering, programs. The techniques of reverse engineering and re-engineering were developed to bridge the gap between the past and the present. Although reverse engineering can be used for generating missing documentation, it can also be used as a means to demonstrate quality in these older programs. This paper presents, in the form of a case study, how Rolls-Royce and Associates Limited addressed the quality issues of reverse engineering and re-engineering. (author)

  14. Field reversal in mirror machines

    International Nuclear Information System (INIS)

    Pearlstein, L.D.; Anderson, D.V.; Boozer, A.H.

    1978-01-01

    This report discusses some of the physics issues anticipated in field-reversed mirrors. The effect of current cancellation due to electrons is described. An estimate is made of the required impurity level to maintain a field-reversed configuration. The SUPERLAYER code is used to simulate the high-β 2XIIB results, and favorable comparisons require inclusion of quasilinear RF turbulence. Impact of a quadrupole field on field-line closure and resonant transport is discussed. A simple self-consistent model of ion currents is presented. Conditions for stability of field-reversed configurations to E x B driven rotations are determined

  15. HLA-G regulatory haplotypes and implantation outcome in couples who underwent assisted reproduction treatment.

    Science.gov (United States)

    Costa, Cynthia Hernandes; Gelmini, Georgia Fernanda; Wowk, Pryscilla Fanini; Mattar, Sibelle Botogosque; Vargas, Rafael Gustavo; Roxo, Valéria Maria Munhoz Sperandio; Schuffner, Alessandro; Bicalho, Maria da Graça

    2012-09-01

    The role of HLA-G in several clinical conditions related to reproduction has been investigated. Important polymorphisms have been found within the 5'URR and 3'UTR regions of the HLA-G promoter. The aim of the present study was to investigate 16 SNPs in the 5'URR and 14-bp insertion/deletion (ins/del) polymorphism located in the 3'UTR region of the HLA-G gene and its possible association with the implantation outcome in couples who underwent assisted reproduction treatments (ART). The case group was composed of 25 ART couples. Ninety-four couples with two or more term pregnancies composed the control group. Polymorphism haplotype frequencies of the HLA-G were determined for both groups. The Haplotype 5, Haplotype 8 and Haplotype 11 were absolute absence in ART couples. The HLA-G*01:01:02a, HLA-G*01:01:02b alleles and the 14-bp ins polymorphism, Haplotype 2, showed an increased frequency in case women and similar distribution between case and control men. However, this susceptibility haplotype is significantly presented in case women and in couple with failure implantation after treatment, which led us to suggest a maternal effect, associated with this haplotype, once their presence in women is related to a higher number of couples who underwent ART. Copyright © 2012. Published by Elsevier Inc.

  16. Sex Reversal in Birds.

    Science.gov (United States)

    Major, Andrew T; Smith, Craig A

    2016-01-01

    Sexual differentiation in birds is controlled genetically as in mammals, although the sex chromosomes are different. Males have a ZZ sex chromosome constitution, while females are ZW. Gene(s) on the sex chromosomes must initiate gonadal sex differentiation during embryonic life, inducing paired testes in ZZ individuals and unilateral ovaries in ZW individuals. The traditional view of avian sexual differentiation aligns with that expounded for other vertebrates; upon sexual differentiation, the gonads secrete sex steroid hormones that masculinise or feminise the rest of the body. However, recent studies on naturally occurring or experimentally induced avian sex reversal suggest a significant role for direct genetic factors, in addition to sex hormones, in regulating sexual differentiation of the soma in birds. This review will provide an overview of sex determination in birds and both naturally and experimentally induced sex reversal, with emphasis on the key role of oestrogen. We then consider how recent studies on sex reversal and gynandromorphic birds (half male:half female) are shaping our understanding of sexual differentiation in avians and in vertebrates more broadly. Current evidence shows that sexual differentiation in birds is a mix of direct genetic and hormonal mechanisms. Perturbation of either of these components may lead to sex reversal. © 2016 S. Karger AG, Basel.

  17. Reverse engineering of RFID devices

    NARCIS (Netherlands)

    Bokslag, W.

    2015-01-01

    This paper discusses the relevance and potential impact of both RFID and reverse engineering of RFID technology, followed by a discussion of common protocols and internals of RFID technology. The focus of the paper is on providing an overview of the different approaches to reverse engineering RFID

  18. Extreme reversed sexual dichromatism in a bird without sex role reversal.

    Science.gov (United States)

    Heinsohn, Robert; Legge, Sarah; Endler, John A

    2005-07-22

    Brilliant plumage is typical of male birds, reflecting differential enhancement of male traits when females are the limiting sex. Brighter females are thought to evolve exclusively in response to sex role reversal. The striking reversed plumage dichromatism of Eclectus roratus parrots does not fit this pattern. We quantify plumage color in this species and show that very different selection pressures are acting on males and females. Male plumage reflects a compromise between the conflicting requirements for camouflage from predators while foraging and conspicuousness during display. Females are liberated from the need for camouflage but compete for rare nest hollows.

  19. Economic impact of reversion

    International Nuclear Information System (INIS)

    2005-01-01

    Estimations of the Norwegian hydropower production and various reversion models' market value have been made. The value of the Norwegian hydropower production until 01.01.2007 is estimated to about Nok 289 billion after taxes, or about 2,42 Nok/kWh medium production, given an expected future electricity price of around 0,25 Nok/kWh and a discount rate at 6,5 percent in nominal terms after taxes. The estimate is slightly above the level of prices for Norwegian hydropower plants in the last 8-10 years. The value of reversion in private plants which today have a limited licence time is estimated to Nok 5,5 billion. The value of reversion in public-owned Norwegian hydropower plants are about Nok 21 billion with a 60 year licence period from 01.01.2007, and about 12 billion for 75 years (ml)

  20. Intramolecular cyclization in irradiated nucleic acids: correlation between high-performance liquid chromatography and an immunochemical assay for 8,5'-cycloadenosine in irradiated poly(A)

    International Nuclear Information System (INIS)

    Fuciarelli, A.F.; Shum, F.Y.; Raleigh, J.A.

    1987-01-01

    A correlation between high-performance liquid chromatography (HPLC) analysis and an in situ enzyme-linked immunosorbent assay (ELISA) for 8,5'-cycloadenosine formation in irradiated poly(A) has been established. The correlation shows that the ELISA precisely reflects changes in the combined yield of R- and S-8,5'-cycloadenosine but that a correction factor must be applied to the ELISA values for accuracy. The HPLC analysis reveals that the intramolecular cyclization proceeds stereoselectively in irradiated poly(A) to preferentially produce the R isomer at pH 7.0 which is similar to the result for irradiated adenosine but in contrast to the result for 5'-AMP where the S isomer predominates at neutral pH. The HPLC analysis shows that two events originating in hydroxyl radical attack at the sugar phosphate backbone in poly(A); that is, adenine release and 8,5'-cycloadenosine formation have somewhat different dose-yield responses. The formation of 8-hydroxyadenosine was detected in the HPLC chromatograms of poly(A) irradiated under N2O at neutral pH, and the yield of this compound was similar to the yield observed in 5'-AMP or adenosine irradiated under similar conditions

  1. Reverse-symmetry waveguides: Theory and fabrication

    DEFF Research Database (Denmark)

    Horvath, R.; Lindvold, Lars René; Larsen, N.B.

    2002-01-01

    We present an extensive theoretical analysis of reverse-symmetry waveguides with special focus on their potential application as sensor components in aqueous media and demonstrate a novel method for fabrication of such waveguides. The principle of reverse symmetry is based on making the refractive...... index of the waveguide substrate less than the refractive index of the medium covering the waveguiding film (n(water) = 1.33). This is opposed to the conventional waveguide geometry, where the substrate is usually glass or polymers with refractive indices of approximate to1.5. The reverse configuration...... are combined with air-grooved polymer supports to form freestanding single-material polymer waveguides of reverse symmetry capable of guiding light....

  2. Design of a novel quantum reversible ternary up-counter

    Science.gov (United States)

    Houshmand, Pouran; Haghparast, Majid

    2015-08-01

    Reversible logic has been recently considered as an interesting and important issue in designing combinational and sequential circuits. The combination of reversible logic and multi-valued logic can improve power dissipation, time and space utilization rate of designed circuits. Only few works have been reported about sequential reversible circuits and almost there are no paper exhibited about quantum ternary reversible counter. In this paper, first we designed 2-qutrit and 3-qutrit quantum reversible ternary up-counters using quantum ternary reversible T-flip-flop and quantum reversible ternary gates. Then we proposed generalized quantum reversible ternary n-qutrit up-counter. We also introduced a new approach for designing any type of n-qutrit ternary and reversible counter. According to the results, we can conclude that applying second approach quantum reversible ternary up-counter is better than the others.

  3. Kinematic reversal schemes for the geomagnetic dipole.

    Science.gov (United States)

    Levy, E. H.

    1972-01-01

    Fluctuations in the distribution of cyclonic convective cells, in the earth's core, can reverse the sign of the geomagnetic field. Two kinematic reversal schemes are discussed. In the first scheme, a field maintained by cyclones concentrated at low latitude is reversed by a burst of cyclones at high latitude. Conversely, in the second scheme, a field maintained predominantly by cyclones in high latitudes is reversed by a fluctuation consisting of a burst of cyclonic convection at low latitude. The precise fluid motions which produce the geomagnetic field are not known. However, it appears that, whatever the details are, a fluctuation in the distribution of cyclonic cells over latitude can cause a geomagnetic reversal.

  4. Intraoperative seizures and seizures outcome in patients underwent awake craniotomy.

    Science.gov (United States)

    Yuan, Yang; Peizhi, Zhou; Xiang, Wang; Yanhui, Liu; Ruofei, Liang; Shu, Jiang; Qing, Mao

    2016-11-25

    Awake craniotomies (AC) could reduce neurological deficits compared with patients under general anesthesia, however, intraoperative seizure is a major reason causing awake surgery failure. The purpose of the study was to give a comprehensive overview the published articles focused on seizure incidence in awake craniotomy. Bibliographic searches of the EMBASE, MEDLINE,were performed to identify articles and conference abstracts that investigated the intraoperative seizure frequency of patients underwent AC. Twenty-five studies were included in this meta-analysis. Among the 25 included studies, one was randomized controlled trials and 5 of them were comparable studies. The pooled data suggested the general intraoperative seizure(IOS) rate for patients with AC was 8%(fixed effect model), sub-group analysis identified IOS rate for glioma patients was 8% and low grade patients was 10%. The pooled data showed early seizure rates of AC patients was 11% and late seizure rates was 35%. This systematic review and meta-analysis shows that awake craniotomy is a safe technique with relatively low intraoperative seizure occurrence. However, few RCTs were available, and the acquisition of further evidence through high-quality RCTs is highly recommended.

  5. Theory of field-reversed mirrors and field-reversed plasma-gun experiments. Paper IAEA-CN-38/R-2

    International Nuclear Information System (INIS)

    Anderson, D.V.; Auerbach, S.P.; Berk, H.L.

    1980-01-01

    Experimental and theoretical studies of field reversal in a mirror machine are reported. Plasma-gun experiments demonstrate that reversed-field plasma layers are formed. Low energy plasma flowing behind the initially produced plasma front prevents tearing of the layer from the gun muzzle. MHD simulation shows that tearing can be obtained by impeding the slow plasma flow with a plasma divider. It is demonstrated theoretically that a field-reversed mirror imbedded in a multipole field can be sustained in steady state with neutral-beam injection even in the absence of impurities. MHD stability analysis shows that growth rates of elongated reversed-field theta-pinch configurations decrease with axial extension, which indicates the importance of including finite Larmor radius in the analysis. Tilting-mode criteria are improved by proper shaping, and a problimak shape is proposed. Tearing mode stability of reversed-field theta-pinches is greatly enhanced by flux exclusion. Self-consistent, 1-1/2-dimensional transport codes have been developed, and initial results are presented

  6. Theory of field-reversed mirrors and field-reversed plasma-gun experiments. Paper IAEA-CN-38/R-2

    International Nuclear Information System (INIS)

    Anderson, D.V.; Auerbach, S.P.; Berk, H.L.

    1980-01-01

    Experimental and theoretical studies of field reversal in a mirror machine are reported. Plasma-gun experiments demonstrate that reversed-field plasma layers are formed. Low energy plasma flowing behind the initially produced plasma front prevents tearing of the layer from the gun muzzle. MHD simulation shows that tearing can be obtained by impeding the slow plasma flow with a plasma divider. It is demonstrated theoretically that a field-reversed mirror imbedded in a multipole field can be sustained in steady state with neutral-beam injection even in the absence of impurities. MHD stability analysis shows that growth rates of elongated reversed-field theta-pinch configurations decrease with axial extension, which indicates the importance of including finite Larmor radius in the analysis. Tilting-mode criteria are dramatically improved by proper shaping, and a problimak shape is proposed. Tearing mode stability of reversed-field theta-pinches is greatly enhanced by flux exclusion. Self-consistent, 1-1/2-dimensional transport codes have been developed, and initial results are presented

  7. Reversible deep disposal

    International Nuclear Information System (INIS)

    2009-10-01

    This presentation, given by the national agency of radioactive waste management (ANDRA) at the meeting of October 8, 2009 of the high committee for the nuclear safety transparency and information (HCTISN), describes the concept of deep reversible disposal for high level/long living radioactive wastes, as considered by the ANDRA in the framework of the program law of June 28, 2006 about the sustainable management of radioactive materials and wastes. The document presents the social and political reasons of reversibility, the technical means considered (containers, disposal cavities, monitoring system, test facilities and industrial prototypes), the decisional process (progressive development and blocked off of the facility, public information and debate). (J.S.)

  8. Securing Biometric Images using Reversible Watermarking

    OpenAIRE

    Thampi, Sabu M.; Jacob, Ann Jisma

    2011-01-01

    Biometric security is a fast growing area. Protecting biometric data is very important since it can be misused by attackers. In order to increase security of biometric data there are different methods in which watermarking is widely accepted. A more acceptable, new important development in this area is reversible watermarking in which the original image can be completely restored and the watermark can be retrieved. But reversible watermarking in biometrics is an understudied area. Reversible ...

  9. Reverse genetics of avian metapneumoviruses

    Science.gov (United States)

    An overview of avian metapneumovirus (aMPV) infection in turkeys and development of a reverse genetics system for aMPV subgroup C (aMPV-C) virus will be presented. By using reverse genetics technology, we generated recombinant aMPV-C viruses containing a different length of glycoprotein (G) gene or...

  10. Failed Reverse Total Shoulder Arthroplasty Caused by Recurrent Candida glabrata Infection with Prior Serratia marcescens Coinfection

    Directory of Open Access Journals (Sweden)

    John G. Skedros

    2014-01-01

    Full Text Available This report describes a 58-year-old insulin-dependent diabetic male patient who initially sustained a proximal humerus fracture from a fall. The fracture fixation failed and then was converted to a humeral hemiarthroplasty, which became infected with Candida glabrata and Serratia marcescens. After these infections were believed to be cured with antibacterial and antifungal treatments and two-stage irrigation and debridement, he underwent conversion to a reverse total shoulder arthroplasty. Unfortunately, the C. glabrata infection recurred and, nearly 1.5 years after implantation of the reverse total shoulder, he had a resection arthroplasty (removal of all implants and cement. His surgical and pharmacologic treatment concluded with (1 placement of a tobramycin-impregnated cement spacer also loaded with amphotericin B, with no plan for revision arthroplasty (i.e., the spacer was chronically retained, and (2 chronic use of daily oral fluconazole. We located only three reported cases of Candida species causing infection in shoulder arthroplasties (two C. albicans, one C. parapsilosis. To our knowledge, a total shoulder arthroplasty infected with C. glabrata has not been reported, nor has a case of a C. glabrata and S. marcescens periprosthetic coinfection in any joint. In addition, it is well known that S. marcescens infections are uncommon in periprosthetic joint infections.

  11. Time-dependent reversal of significant intrapulmonary shunt after liver transplantation.

    Science.gov (United States)

    Jin, Xin; Sun, Byung Joo; Song, Jae-Kwan; Roh, Jae-Hyung; Jang, Jeong Yoon; Kim, Dae-Hee; Lim, Young-Suk; Song, Jong-Min; Kang, Duk-Hyun; Lee, Sung Gyu

    2018-03-05

    Although the association between intrapulmonary shunt (IPS) and liver cirrhosis is clear, data of repeated contrast echocardiography (CE) before and after liver transplantation (LT) to evaluate factors associated with IPS are limited. Hand-agitated saline was used for CE and, by assessing left-chamber opacification, IPS was classified as grade 0 to 4. Grade 3/4 constituted significant IPS and hepatopulmonary syndrome (HPS) was defined as significant IPS with the arterial partial pressure of oxygen < 70 mmHg. Before LT, 253 patients underwent CE and the frequency of significant IPS and HPS were 44% (n = 112) and 7% (n = 17), respectively. Child-Pugh score (odds ratio [OR], 1.345; 95% confidence interval [CI], 1.090 to 1.660; p = 0.006) and arterial oxygen content (OR, 0.838; 95% CI, 0.708 to 0.991; p = 0.039) were independent determinants of significant IPS, whereas direct bilirubin (OR, 1.076; 95% CI, 1.012 to 1.144; p = 0.019) was the only variable associated with HPS. Among 153 patients who underwent successful LT, repeated CE was performed in 97 (63%), which showed significant reductions in IPS grade (from 2.6 ± 1.0 to 1.2 ± 1.3, p < 0.001) and the prevalence of significant IPS (from 56% to 20%, p = 0.038). After adjustment for pre-LT IPS grade, time from LT to repeated CE presented negative linear relationship with post-LT IPS grade (r 2 = 0.366, p < 0.001) and was the only determinant of post-LT IPS grade (OR, 1.009; 95% CI, 1.003 to 1.014; p = 0.004). Repeated CE is useful to evaluate intrapulmonary vascular change before and after LT. Reversal of IPS after successful LT is time-dependent and follow-up duration should be considered for accurate assessment of IPS after LT.

  12. Reversal permanent charge and reversal potential: case studies via classical Poisson–Nernst–Planck models

    International Nuclear Information System (INIS)

    Eisenberg, Bob; Liu, Weishi; Xu, Hongguo

    2015-01-01

    In this work, we are interested in effects of a simple profile of permanent charges on ionic flows. We determine when a permanent charge produces current reversal. We adopt the classical Poisson–Nernst–Planck (PNP) models of ionic flows for this study. The starting point of our analysis is the recently developed geometric singular perturbation approach for PNP models. Under the setting in the paper for case studies, we are able to identify a single governing equation for the existence and the value of the permanent charge for a current reversal. A number of interesting features are established. The related topic on reversal potential can be viewed as a dual problem and is briefly examined in this work too. (paper)

  13. THEORETICAL FRAMES FOR DESIGNING REVERSE LOGISTICS PROCESSES

    OpenAIRE

    Janusz K. Grabara; Sebastian Kot

    2009-01-01

    Logistics processes of return flow became more and more important in present business practice. Because of better customer satisfaction, environmental and financial aspects many enterprises deal with reverse logistics performance. The paper is a literature review focused on the design principles of reverse logistics processes Keywords: reverse logistics, designing.

  14. Reversal of target-specific oral anticoagulants

    Science.gov (United States)

    Siegal, D.M.; Cuker, Adam

    2014-01-01

    Target-specific oral anticoagulants (TSOACs) provide safe and effective anticoagulation for the prevention and treatment of thrombosis in a variety of clinical settings by interfering with the activity of thrombin (dabigatran) or factor Xa (rivaroxaban, apixaban, edoxaban, betrixaban). Although TSOACs have practical advantages over vitamin K antagonists (VKAs), there are currently no antidotes to reverse their anticoagulant effect. Herein we summarize the available evidence for TSOAC reversal using nonspecific and specific reversal agents. We discuss important limitations of existing evidence, which is derived from studies in human volunteers, animal models and in vitro experiments. Studies evaluating the safety and efficacy of reversal agents on clinical outcomes such as bleeding and mortality in patients with TSOAC-associated bleeding are needed. PMID:24880102

  15. Optical reversible programmable Boolean logic unit.

    Science.gov (United States)

    Chattopadhyay, Tanay

    2012-07-20

    Computing with reversibility is the only way to avoid dissipation of energy associated with bit erase. So, a reversible microprocessor is required for future computing. In this paper, a design of a simple all-optical reversible programmable processor is proposed using a polarizing beam splitter, liquid crystal-phase spatial light modulators, a half-wave plate, and plane mirrors. This circuit can perform 16 logical operations according to three programming inputs. Also, inputs can be easily recovered from the outputs. It is named the "reversible programmable Boolean logic unit (RPBLU)." The logic unit is the basic building block of many complex computational operations. Hence the design is important in sense. Two orthogonally polarized lights are defined here as two logical states, respectively.

  16. Sarcopenia: a new predictor of postoperative complications for elderly gastric cancer patients who underwent radical gastrectomy.

    Science.gov (United States)

    Zhou, Chong-Jun; Zhang, Feng-Min; Zhang, Fei-Yu; Yu, Zhen; Chen, Xiao-Lei; Shen, Xian; Zhuang, Cheng-Le; Chen, Xiao-Xi

    2017-05-01

    A geriatric assessment is needed to identify high-risk elderly patients with gastric cancer. However, the current geriatric assessment has been considered to be either time-consuming or subjective. The present study aimed to investigate the predictive effect of sarcopenia on the postoperative complications for elderly patients who underwent radical gastrectomy. We conducted a prospective study of patients who underwent radical gastrectomy from August 2014 to December 2015. Computed tomography-assessed lumbar skeletal muscle, handgrip strength, and gait speed were measured to define sarcopenia. Sarcopenia was present in 69 of 240 patients (28.8%) and was associated with lower body mass index, lower serum albumin, lower hemoglobin, and higher nutritional risk screening 2002 scores. Postoperative complications significantly increased in the sarcopenic patients (49.3% versus 24.6%, P sarcopenia (odds ratio: 2.959, 95% CI: 1.629-5.373, P Sarcopenia, presented as a new geriatric assessment factor, was a strong and independent risk factor for postoperative complications of elderly patients with gastric cancer. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. Hidden Randomness between Fitness Landscapes Limits Reverse Evolution

    Science.gov (United States)

    Tan, Longzhi; Serene, Stephen; Xiao Chao, Hui; Gore, Jeff

    2012-02-01

    Natural populations must constantly adapt to the ever-changing environment. A fundamental question in evolutionary biology is whether adaptations can be reversed by returning the population to its ancestral environment. Traditionally, reverse evolution is defined as restoring an ancestral phenotype (physical characteristics such as body size), and the classic Dollo's Law has hypothesized the impossibility of reversing complex adaptations. However, this ``law'' remains ambiguous unless reverse evolution can be studied at the level of genotypes (the underlying genome sequence). We measured the fitness landscapes of a bacterial antibiotic-resistance gene and analyzed the reversibility of evolution as a global, statistical feature of the landscapes. In both experiments and simulations, we find that an adaptation's reversibility declines as the number of mutations it involves increases, suggesting a probabilistic form of Dollo's Law at the molecular level. We also show computationally that slowly switching between environments facilitates reverse evolution in small populations, where clonal interference is negligible or moderate. This is an analogy to thermodynamics, where the reversibility of a physical process is maximized when conditions are modified infinitely slowly.

  18. Reverse logistics in the construction industry.

    Science.gov (United States)

    Hosseini, M Reza; Rameezdeen, Raufdeen; Chileshe, Nicholas; Lehmann, Steffen

    2015-06-01

    Reverse logistics in construction refers to the movement of products and materials from salvaged buildings to a new construction site. While there is a plethora of studies looking at various aspects of the reverse logistics chain, there is no systematic review of literature on this important subject as applied to the construction industry. Therefore, the objective of this study is to integrate the fragmented body of knowledge on reverse logistics in construction, with the aim of promoting the concept among industry stakeholders and the wider construction community. Through a qualitative meta-analysis, the study synthesises the findings of previous studies and presents some actions needed by industry stakeholders to promote this concept within the real-life context. First, the trend of research and terminology related with reverse logistics is introduced. Second, it unearths the main advantages and barriers of reverse logistics in construction while providing some suggestions to harness the advantages and mitigate these barriers. Finally, it provides a future research direction based on the review. © The Author(s) 2015.

  19. Prefix reversals on binary and ternary strings

    NARCIS (Netherlands)

    Hurkens, C.A.J.; Iersel, van L.J.J.; Keijsper, J.C.M.; Kelk, S.M.; Stougie, L.; Tromp, J.T.

    2007-01-01

    Given a permutation $\\pi$, the application of prefix reversal $f^{(i)}$ to $\\pi$ reverses the order of the first $i$ elements of $\\pi$. The problem of sorting by prefix reversals (also known as pancake flipping), made famous by Gates and Papadimitriou (Discrete Math., 27 (1979), pp. 47–57), asks for

  20. Reverse saphenous conduit flap in small animals: Clinical applications and outcomes

    Directory of Open Access Journals (Sweden)

    Ross C. Elliott

    2014-08-01

    Full Text Available Due to the lack of skin elasticity defects of the distal hind limb can be a challenge to close. This article assesses a well-described, but completely under-used technique for closure of wounds on the distal tarsus. The technique was used with good success in six cases presenting to the Bryanston Veterinary Hospital with a wide range of underlying pathology ranging from trauma to neoplastic disease of the tarsus. All six cases were treated with a reverse saphenous conduit flap and two of them underwent radiation therapy with no adverse side effects. All cases showed excellent results with a very low degree of flap necrosis that never exceeded 15% of the total flap area. This skin flap provides an excellent treatment method that is reliable in closure of defects of the distal tarsus with few adverse effects. To the author’s knowledge there has been only one previously published report on the clinical use of this type of skin flap,even though the flap is well described in most texts.

  1. Rotating Reverse-Osmosis for Water Purification

    Science.gov (United States)

    Lueptow, RIchard M.

    2004-01-01

    A new design for a water-filtering device combines rotating filtration with reverse osmosis to create a rotating reverse- osmosis system. Rotating filtration has been used for separating plasma from whole blood, while reverse osmosis has been used in purification of water and in some chemical processes. Reverse- osmosis membranes are vulnerable to concentration polarization a type of fouling in which the chemicals meant not to pass through the reverse-osmosis membranes accumulate very near the surfaces of the membranes. The combination of rotating filtration and reverse osmosis is intended to prevent concentration polarization and thereby increase the desired flux of filtered water while decreasing the likelihood of passage of undesired chemical species through the filter. Devices based on this concept could be useful in a variety of commercial applications, including purification and desalination of drinking water, purification of pharmaceutical process water, treatment of household and industrial wastewater, and treatment of industrial process water. A rotating filter consists of a cylindrical porous microfilter rotating within a stationary concentric cylindrical outer shell (see figure). The aqueous suspension enters one end of the annulus between the inner and outer cylinders. Filtrate passes through the rotating cylindrical microfilter and is removed via a hollow shaft. The concentrated suspension is removed at the end of the annulus opposite the end where the suspension entered.

  2. Combining or Separating Forward and Reverse Logistics

    DEFF Research Database (Denmark)

    Herbert-Hansen, Zaza Nadja Lee; Larsen, Samuel; Nielsen, Anders

    2018-01-01

    Purpose – While forward logistics handles and manages the flow of goods downstream in the supply chain from suppliers to customers, reverse logistics (RL) manages the flow of returned goods upstream. A firm can combine reverse logistics with forward logistics, keep the flows separated, or choose......-research addresses intra-RL issues while the relationship between forward and reverse logistics is under-researched. This paper contributes to RL-theory by identifying the contextual factors that determine the most advantageous relationship between forward and reverse logistics, and proposes a novel decision making...

  3. Parameter dependence of resonant spin torque magnetization reversal

    International Nuclear Information System (INIS)

    Fricke, L.; Serrano-Guisan, S.; Schumacher, H.W.

    2012-01-01

    We numerically study ultra fast resonant spin torque (ST) magnetization reversal in magnetic tunneling junctions (MTJ) driven by current pulses having a direct current (DC) and a resonant alternating current (AC) component. The precessional ST dynamics of the single domain MTJ free layer cell are modeled in the macro spin approximation. The energy efficiency, reversal time, and reversal reliability are investigated under variation of pulse parameters like direct and AC current amplitude, AC frequency and AC phase. We find a range of AC and direct current amplitudes where robust resonant ST reversal is obtained with faster switching time and reduced energy consumption per pulse compared to purely direct current ST reversal. However, for a certain range of AC and direct current amplitudes a strong dependence of the reversal properties on AC frequency and phase is found. Such regions of unreliable reversal must be avoided for ST memory applications.

  4. Parameter dependence of resonant spin torque magnetization reversal

    Science.gov (United States)

    Fricke, L.; Serrano-Guisan, S.; Schumacher, H. W.

    2012-04-01

    We numerically study ultra fast resonant spin torque (ST) magnetization reversal in magnetic tunneling junctions (MTJ) driven by current pulses having a direct current (DC) and a resonant alternating current (AC) component. The precessional ST dynamics of the single domain MTJ free layer cell are modeled in the macro spin approximation. The energy efficiency, reversal time, and reversal reliability are investigated under variation of pulse parameters like direct and AC current amplitude, AC frequency and AC phase. We find a range of AC and direct current amplitudes where robust resonant ST reversal is obtained with faster switching time and reduced energy consumption per pulse compared to purely direct current ST reversal. However, for a certain range of AC and direct current amplitudes a strong dependence of the reversal properties on AC frequency and phase is found. Such regions of unreliable reversal must be avoided for ST memory applications.

  5. 21 CFR 177.2550 - Reverse osmosis membranes.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Reverse osmosis membranes. 177.2550 Section 177... Components of Articles Intended for Repeated Use § 177.2550 Reverse osmosis membranes. Substances identified in paragraph (a) of this section may be safely used as reverse osmosis membranes intended for use in...

  6. Prefix reversals on binary and ternary strings

    NARCIS (Netherlands)

    Hurkens, C.A.J.; van Iersel, L.J.J.; Keijsper, J.C.M.; Kelk, S.M.; Stougie, L.; Tromp, J.T.

    2007-01-01

    Given a permutation $\\pi$, the application of prefix reversal $f^{(i)}$ to $\\pi$ reverses the order of the first $i$ elements of $\\pi$. The problem of sorting by prefix reversals (also known as pancake flipping), made famous by Gates and Papadimitriou (Discrete Math., 27 (1979), pp. 47–57), asks

  7. Reverse innovation in maternal health.

    Science.gov (United States)

    Firoz, Tabassum; Makanga, Prestige Tatenda; Nathan, Hannah L; Payne, Beth; Magee, Laura A

    2017-09-01

    Reverse innovation, defined as the flow of ideas from low- to high-income settings, is gaining traction in healthcare. With an increasing focus on value, investing in low-cost but effective and innovative solutions can be of mutual benefit to both high- and low-income countries. Reverse innovation has a role in addressing maternal health challenges in high-income countries by harnessing these innovative solutions for vulnerable populations especially in rural and remote regions. In this paper, we present three examples of 'reverse innovation' for maternal health: a low-cost, easy-to-use blood pressure device (CRADLE), a diagnostic algorithm (mini PIERS) and accompanying mobile app (PIERS on the Move), and a novel method for mapping maternal outcomes (MOM).

  8. Synthesis and antitumor activity of some novel thiophene, pyrimidine, coumarin, pyrazole and pyridine derivatives

    Directory of Open Access Journals (Sweden)

    Albratty Mohammed

    2017-03-01

    Full Text Available 2-Cyano-N-(thiazol-2-yl acetamide (2a and 2-cyano-N-(oxazol- 2-yl acetamide (2b were obtained via the reaction of ethyl cyanoacetate with either 2-aminothiazole (1a or 2-aminooxazole (1b. The formed products were directed toward the reaction with cyclopentanone and elemental sulfur in the presence of triethylamine to give cyclopenta[b]thiophene derivatives (3a,b. The latter products were reacted with either ethyl cyanoacetate or malononitrile to form compounds 4a,b and 5a,b, respectively. Compounds 4a,b were aimed at synthesizing some heterocyclic compounds; thus internal cyclization reactions were introduced to form compounds 6a,b. Also, compounds 4a,b reacted with salicylaldehyde, hydrazine derivatives and either urea or thiourea to produce coumarin derivatives (7a,b, pyrazole derivatives (8a-d and pyrimidine derivatives (9a-d, respectively. Reaction of either benzaldehyde or benzene diazonium chloride (11 with compounds 4a,b afforded compounds 10a,b and 12a,b, respectively. On the other hand, compounds 5a,b underwent internal cyclization to form pyrimidine derivatives 13a,b. Also, when compounds 5a,b reacted with either ethyl cyanoacetate or malononitrile, they gave pyridine derivatives (15a-d through the formation of intermediates (14a-d. Finally, formation of fused pyrimidine derivatives (17a,b was achieved through the reaction of compounds 5a,b and salicylaldehyde applying two different pathways. The first pathway used a catalytic amount of piperidine to form compounds 16a,b; the latter products underwent cyclization to give compounds 17a,b. The second pathway, using a catalytic amount of sodium ethoxide solution directly in one step, afforded compounds 17a,b. Structures of the newly synthesized compounds were established using IR, 1H NMR, 13C NMR and mass spectrometry and their antitumor activity was investigated. Some of these compounds showed promising inhibitory effects on three different cell lines. However, fused pyrimidine

  9. [A Case of Ascending Colon Cancer with Lynch Syndrome Who Underwent XELOX Adjuvant Chemotherapy].

    Science.gov (United States)

    Takase, Koki; Murata, Kohei; Kagawa, Yoshinori; Nose, Yohei; Kawai, Kenji; Sakamoto, Takuya; Naito, Atsushi; Murakami, Kohei; Katsura, Yoshiteru; Omura, Yoshiaki; Takeno, Atsushi; Nakatsuka, Shinichi; Takeda, Yutaka; Kato, Takeshi; Tamura, Shigeyuki

    2018-01-01

    Lynch syndrome is an inherited syndrome with the development of the colorectal and various other cancers. Lynch syndrome is caused by mutations in the mismatch repair genes. A 33 year-old male underwent XELOX adjuvant chemotherapy for ascending colon cancer with Lynch syndrome. Although efficacy of 5-FU is not demonstrated in Lynch syndrome, MOSAIC trial had suggested a benefit from FOLFOX compared with 5-FU in patients who have colorectal cancer with Lynch syndrome. Oxaliplatin-based adjuvant chemotherapy can be a therapeutic option for colorectal cancer in lynch syndrome patients.

  10. Stability of the field-reversed mirror

    International Nuclear Information System (INIS)

    Morse, E.C.

    1979-01-01

    The stability of a field reversed mirror plasma configuration is studied with an energy principle derived from the Vlasov equation. Because of finite orbit effects, the stability properties of a field-reversed mirror are different from the stability properties of similar magnetohydrodynamic equilibria. The Vlasov energy principle developed here is applied to a computer simulation of an axisymmetric field-reversed mirror state. It has been possible to prove that the l = 0 modes, called tearing modes, satisfy a sufficient condition for stability. Precessional modes, with l = 1, 2, are found to be unstable at low growth rate. This suggests possible turbulent behavior (Bohm confinement) in the experimental devices aiming at field reversal. Techniques for suppressing these instabilities are outlined, and the applicability of the Vlasov energy principle to more complicated equilibrium models is shown

  11. Reversible Lithium Neurotoxicity: Review of the Literature

    Science.gov (United States)

    Netto, Ivan

    2012-01-01

    Objective: Lithium neurotoxicity may be reversible or irreversible. Reversible lithium neurotoxicity has been defined as cases of lithium neurotoxicity in which patients recovered without any permanent neurologic sequelae, even after 2 months of an episode of lithium toxicity. Cases of reversible lithium neurotoxicity differ in clinical presentation from those of irreversible lithium neurotoxicity and have important implications in clinical practice. This review aims to study the clinical presentation of cases of reversible lithium neurotoxicity. Data Sources: A comprehensive electronic search was conducted in the following databases: MEDLINE (PubMed), 1950 to November 2010; PsycINFO, 1967 to November 2010; and SCOPUS (EMBASE), 1950 to November 2010. MEDLINE and PsycINFO were searched by using the OvidSP interface. Study Selection: A combination of the following search terms was used: lithium AND adverse effects AND central nervous system OR neurologic manifestation. Publications cited include articles concerned with reversible lithium neurotoxicity. Data Extraction: The age, sex, clinical features, diagnostic categories, lithium doses, serum lithium levels, precipitating factors, and preventive measures of 52 cases of reversible lithium neurotoxicity were extracted. Data Synthesis: Among the 52 cases of reversible lithium neurotoxicity, patients ranged in age from 10 to 80 years and a greater number were female (P = .008). Most patients had affective disorders, schizoaffective disorders, and/or depression (P lithium levels were less than or equal to 1.5 mEq/L (P lithium, underlying brain pathology, abnormal tissue levels, specific diagnostic categories, and elderly populations were some of the precipitating factors reported for reversible lithium neurotoxicity. The preventive measures were also described. Conclusions: Reversible lithium neurotoxicity presents with a certain clinical profile and precipitating factors for which there are appropriate

  12. Reversible lithium neurotoxicity: review of the literatur.

    Science.gov (United States)

    Netto, Ivan; Phutane, Vivek H

    2012-01-01

    Lithium neurotoxicity may be reversible or irreversible. Reversible lithium neurotoxicity has been defined as cases of lithium neurotoxicity in which patients recovered without any permanent neurologic sequelae, even after 2 months of an episode of lithium toxicity. Cases of reversible lithium neurotoxicity differ in clinical presentation from those of irreversible lithium neurotoxicity and have important implications in clinical practice. This review aims to study the clinical presentation of cases of reversible lithium neurotoxicity. A comprehensive electronic search was conducted in the following databases: MEDLINE (PubMed), 1950 to November 2010; PsycINFO, 1967 to November 2010; and SCOPUS (EMBASE), 1950 to November 2010. MEDLINE and PsycINFO were searched by using the OvidSP interface. A combination of the following search terms was used: lithium AND adverse effects AND central nervous system OR neurologic manifestation. Publications cited include articles concerned with reversible lithium neurotoxicity. The age, sex, clinical features, diagnostic categories, lithium doses, serum lithium levels, precipitating factors, and preventive measures of 52 cases of reversible lithium neurotoxicity were extracted. Among the 52 cases of reversible lithium neurotoxicity, patients ranged in age from 10 to 80 years and a greater number were female (P = .008). Most patients had affective disorders, schizoaffective disorders, and/or depression (P lithium levels were less than or equal to 1.5 mEq/L (P lithium, underlying brain pathology, abnormal tissue levels, specific diagnostic categories, and elderly populations were some of the precipitating factors reported for reversible lithium neurotoxicity. The preventive measures were also described. Reversible lithium neurotoxicity presents with a certain clinical profile and precipitating factors for which there are appropriate preventive measures. This recognition will help in early diagnosis and prompt treatment of

  13. Establishment of a reversible model of prehepatic portal hypertension in rats.

    Science.gov (United States)

    Zhao, Xin; Dou, Jian; Gao, Qing-Jun

    2016-08-01

    The aim of the present study was to improve upon the traditional model of pre-hepatic portal hypertension in rats, and simulate the anhepatic phase of orthotopic liver transplantation without veno-venous bypass. A reversible model of portal hypertension was induced by portal vein ligation, with a label ring ligated along the portal vein. A total of 135 male Wistar rats were divided into three groups: i) Normal control (NC) group; ii) portal hypertensive control (PHTC) group; and iii) reperfusion (R) group. In the R group, rats with portal hypertension underwent simultaneous clamping of the portal triad and retrohepatic vena cava for 1 h, followed by removal of the clamps to enable blood reperfusion. Portal venography and portal vein pressure were recorded during the surgery. Arterial oxygen pressure (PaO 2 ), and alanine aminotransferase (ALT), aspartate aminotransferase (AST) and total bilirubin (TBil) levels were determined, and pathological changes of the liver were investigated by immunohistochemical staining. The results demonstrated that, 3 weeks after portal vein ligation, the vein area and the free portal pressures in the PHTC group were significantly increased compared with those in the NC group. The serum ALT and AST levels in the R group at different time points were significantly elevated compared with those in the PHTC group, and reached their maximal levels at 24 h after reperfusion. Furthermore, the PaO 2 at 24 h after reperfusion was significantly decreased. In conclusion, the reversible model of pre-hepatic portal hypertension in rats was successfully established using the introduction of a label ring. This model may be useful for basic research focusing on the anhepatic phase of orthotopic liver transplantation without veno-venous bypass.

  14. Impact of INR monitoring, reversal agent use, heparin bridging, and anticoagulant interruption on rebleeding and thromboembolism in acute gastrointestinal bleeding.

    Directory of Open Access Journals (Sweden)

    Naoyoshi Nagata

    Full Text Available Anticoagulant management of acute gastrointestinal bleeding (GIB during the pre-endoscopic period has not been fully addressed in American, European, or Asian guidelines. This study sought to evaluate the risks of rebleeding and thromboembolism in anticoagulated patients with acute GIB.Baseline, endoscopy, and outcome data were reviewed for 314 patients with acute GIB: 157 anticoagulant users and 157 age-, sex-, and important risk-matched non-users. Data were also compared between direct oral anticoagulants (DOACs and warfarin users.Between anticoagulant users and non-users, of whom 70% underwent early endoscopy, no endoscopy-related adverse events or significant differences were found in the rate of endoscopic therapy need, transfusion need, rebleeding, or thromboembolism. Rebleeding was associated with shock, comorbidities, low platelet count and albumin level, and low-dose aspirin use but not HAS-BLED score, any endoscopic results, heparin bridge, or international normalized ratio (INR ≥ 2.5. Risks for thromboembolism were INR ≥ 2.5, difference in onset and pre-endoscopic INR, reversal agent use, and anticoagulant interruption but not CHA2DS2-VASc score, any endoscopic results, or heparin bridge. In patients without reversal agent use, heparin bridge, or anticoagulant interruption, there was only one rebleeding event and no thromboembolic events. Warfarin users had a significantly higher transfusion need than DOACs users.Endoscopy appears to be safe for anticoagulant users with acute GIB compared with non-users. Patient background factors were associated with rebleeding, whereas anticoagulant management factors (e.g. INR correction, reversal agent use, and drug interruption were associated with thromboembolism. Early intervention without reversal agent use, heparin bridge, or anticoagulant interruption may be warranted for acute GIB.

  15. Monoamines stimulate sex reversal in the saddleback wrasse.

    Science.gov (United States)

    Larson, Earl T; Norris, David O; Gordon Grau, E; Summers, Cliff H

    2003-02-15

    Monoamine neurotransmitters (norepinephrine, dopamine, and serotonin) play an important role in reproduction and sexual behavior throughout the vertebrates. They are the first endogenous chemical signals in the regulation of the hypothalamo-pituitary-gonadal (HPG) axis. In teleosts with behavioral sex determination, much is known about behavioral cues that induce sex reversal. The cues are social, processed via the visual system and depend on the ratio of females to males in the population. The mechanisms by which these external behavioral cues are converted to an internal chemical regulatory process are largely unknown. The protogynous Hawaiian saddleback wrasse, Thalassoma duperrey, was used to investigate the biological pathway mediating the conversion of a social cue into neuroendocrine events regulating sex reversal. Because monoamines play an important role in the regulation of the HPG axis, they were selected as likely candidates for such a conversion. To determine if monoamines could affect sex reversal, drugs affecting monoamines were used in an attempt to either induce sex reversal under non-permissive conditions, or prevent sex reversal under permissive conditions. Increasing norepinephrine or blocking dopamine or serotonin lead to sex reversal in experimental animals under non-permissive conditions. Increasing serotonin blocked sex reversal under permissive conditions, while blocking dopamine or norepinephrine retarded the process. The results presented here demonstrate that monoamines contribute significantly to the control sex reversal. Norepinephrine stimulates initiation and completion of gonadal sex of reversal as well as color change perhaps directly via its effects on the HPG axis. Dopamine exercises inhibitory action on the initiation of sex reversal while 5-HT inhibits both initiation and completion of sex reversal. The serotonergic system appears to be an integral part of the pathway mediating the conversion of a social cue into a

  16. β-Elemene Reverses Chemoresistance of Breast Cancer Cells by Reducing Resistance Transmission via Exosomes

    Directory of Open Access Journals (Sweden)

    Jun Zhang

    2015-07-01

    Full Text Available Background: Currently, exosomes that act as mediators of intercellular communication are being researched extensively. Our previous studies confirmed that these exosomes contain microRNAs (miRNAs that could alter chemo-susceptibility, which is partly attributed to the successful intercellular transfer of multidrug resistance (MDR-specific miRNAs. We also confirmed that β-elemene could influence MDR-related miRNA expression and regulate the expression of the target genes PTEN and Pgp, which may lead to the reversal of the chemoresistant breast cancer (BCA cells. We are the first to report these findings, and we propose the following logical hypothesis: β-elemene can mediate MDR-related miRNA expression in cells, thereby affecting the exosome contents, reducing chemoresistance transmission via exosomes, and reversing the drug resistance of breast cancer cells. Methods: MTT-cytotoxic, miRNA microarray, real-time quantitative PCR, Dual Luciferase Activity Assay, and Western blot analysis were performed to investigate the impact of β-elemene on the expression of chemoresistance specific miRNA and PTEN as well as Pgp in chemoresistant BCA exosomes. Results: Drug resistance can be reversed by β-elemene related to exosomes. There were 104 differentially expressed miRNAs in the exosomes of two chemoresistant BCA cells: adriacin (Adr - resistant MCF-7 cells (MCF-7/Adr and docetaxel (Doc - resistant MCF-7 cells (MCF-7/Doc that underwent treatment. Of these, 31 miRNAs were correlated with the constant changes in the MDR. The expression of miR-34a and miR-452 can lead to changes in the characteristics of two chemoresistant BCA exosomes: MCF-7/Adr exosomes (A/exo and MCF-7/Doc exosomes (D/exo. The PTEN expression affected by β-elemene was significantly increased, and the Pgp expression affected by β-elemene was significantly decreased in both cells and exosomes. β-elemene induced a significant increase in the apoptosis rate in both MCF-7/Doc and MCF-7

  17. On flow reversals in Rayleigh-Bénard convection

    International Nuclear Information System (INIS)

    Chandra, Mani; Verma, Mahendra K

    2011-01-01

    The dynamics of flow reversals are studied numerically using Fourier mode analysis. Our analysis shows that the Fourier modes represent the large-scale flows accurately. We observe that during the reversals, the amplitude of one of the large-scale modes vanishes, while another mode rises sharply, very similar to the cessation-led reversals observed earlier in experiments and numerical simulations. The Fourier coefficients of the RBC equations obey certain symmetries properties, which dictates which modes change sign in flow reversals. Based on our simulation results and symmetry properties of the Fourier modes, we provide a qualitative explanation for the flow reversals.

  18. Clean translation of an imperative reversible programming language

    DEFF Research Database (Denmark)

    Axelsen, Holger Bock

    2011-01-01

    We describe the translation techniques used for the code generation in a compiler from the high-level reversible imperative programming language Janus to the low-level reversible assembly language PISA. Our translation is both semantics preserving (correct), in that target programs compute exactly...... the same functions as their source programs (cleanly, with no extraneous garbage output), and efficient, in that target programs conserve the complexities of source programs. In particular, target programs only require a constant amount of temporary garbage space. The given translation methods are generic......, and should be applicable to any (imperative) reversible source language described with reversible flowcharts and reversible updates. To our knowledge, this is the first compiler between reversible languages where the source and target languages were independently developed; the first exhibiting both...

  19. Parkinson’s disease managing reversible neurodegeneration

    Directory of Open Access Journals (Sweden)

    Hinz M

    2016-04-01

    Full Text Available Marty Hinz,1 Alvin Stein,2 Ted Cole,3 Beth McDougall,4 Mark Westaway5 1Clinical Research, NeuroResearch Clinics, Inc., Cape Coral, FL, 2Stein Orthopedic Associates, Plantation, FL, 3Cole Center for Healing, Cincinnati, OH, 4CLEARCenter of Health, Mill Valley, CA, USA; 5Four Pillars Health, Brendale, QLD, Australia Abstract: Traditionally, the Parkinson’s disease (PD symptom course has been classified as an irreversible progressive neurodegenerative disease. This paper documents 29 PD and treatment-induced systemic depletion etiologies which cause and/or exacerbate the seven novel primary relative nutritional deficiencies associated with PD. These reversible relative nutritional deficiencies (RNDs may facilitate and accelerate irreversible progressive neurodegeneration, while other reversible RNDs may induce previously undocumented reversible pseudo-neurodegeneration that is hiding in plain sight since the symptoms are identical to the symptoms being experienced by the PD patient. Documented herein is a novel nutritional approach for reversible processes management which may slow or halt irreversible progressive neurodegenerative disease and correct reversible RNDs whose symptoms are identical to the patient’s PD symptoms. Keywords: Parkinson’s disease, L-dopa, carbidopa, B6, neurodegeneration

  20. AN OVERVIEW ON RETAIL REVERSE LOGISTICS

    Directory of Open Access Journals (Sweden)

    Ioana Olariu

    2014-07-01

    Full Text Available This article is a theoretical approach on retail reverse logistics. Environmental concern and the current marketing strategy have spurred retailers to implement strategies to facilitate product returns from end customers. Reverse logistics, indicating the process of this return flow, encompasses such activities as the movement of returned products, facilities to accommodate returned items, and overall remedy process for returned items. The retail industry, under great competitive pressure, has used return policies as a competitive weapon. Grocery retailers were the first to begin to focus serious attention on the problem of returns and to develop reverse logistics innovations. Grocery retailers first developed innovations such as reclamation centers. Reclamation centers, in turn, led to the establishment of centralized return centers. Centralizing returns has led to significant benefits for most firms that have implemented them. Over the last several years, retailers have consolidated. Now, more than ever, reverse logistics is seen as being important. This reverse distribution activity can be crucial to the survival of companies, because the permanent goodwill of the company is at stake. Businesses succeed because they respond to both external and internal changes and adjust in an effective manner to remain competitive.

  1. Parallelization of Reversible Ripple-carry Adders

    DEFF Research Database (Denmark)

    Thomsen, Michael Kirkedal; Axelsen, Holger Bock

    2009-01-01

    The design of fast arithmetic logic circuits is an important research topic for reversible and quantum computing. A special challenge in this setting is the computation of standard arithmetical functions without the generation of \\emph{garbage}. Here, we present a novel parallelization scheme...... wherein $m$ parallel $k$-bit reversible ripple-carry adders are combined to form a reversible $mk$-bit \\emph{ripple-block carry adder} with logic depth $\\mathcal{O}(m+k)$ for a \\emph{minimal} logic depth $\\mathcal{O}(\\sqrt{mk})$, thus improving on the $mk$-bit ripple-carry adder logic depth $\\mathcal...

  2. Time reversibility in the quantum frame

    Energy Technology Data Exchange (ETDEWEB)

    Masot-Conde, Fátima [Escuela Superior Ingenieros, Dpt. Física Aplicada III, Universidad de Sevilla Isla Mágica, 41092- Sevilla (Spain)

    2014-12-04

    Classic Mechanics and Electromagnetism, conventionally taken as time-reversible, share the same concept of motion (either of mass or charge) as the basis of the time reversibility in their own fields. This paper focuses on the relationship between mobile geometry and motion reversibility. The goal is to extrapolate the conclusions to the quantum frame, where matter and radiation behave just as elementary mobiles. The possibility that the asymmetry of Time (Time’s arrow) is an effect of a fundamental quantum asymmetry of elementary particles, turns out to be a consequence of the discussion.

  3. Early and mid-term results of autograft rescue by Ross reversal: A one-valve disease need not become a two-valve disease.

    Science.gov (United States)

    Hussain, Syed T; Majdalany, David S; Dunn, Aaron; Stewart, Robert D; Najm, Hani K; Svensson, Lars G; Houghtaling, Penny L; Blackstone, Eugene H; Pettersson, Gösta B

    2018-02-01

    Risk of reoperation and loss of a second native valve are major drawbacks of the Ross operation. Rather than discarding the failed autograft, it can be placed back into the native pulmonary position by "Ross reversal." We review our early and mid-term results with this operation. From 2006 to 2017, 39 patients underwent reoperation for autograft dysfunction. The autograft was successfully rescued in 35 patients: by Ross reversal in 30, David procedure in 4, and autograft repair in 1. Medical records were reviewed for patient characteristics (mean age was 46 ± 13 years, range 18-67 years, and 23 were male), previous operations, indications for reoperation, hospital outcomes, and echocardiographic findings for the 30 patients undergoing successful Ross reversal. Follow-up was 4.1 ± 3.5 years (range 7 months-11 years). Median interval between the original Ross procedure and Ross reversal was 12 years (range 5-19 years). Eight patients also had absolute indications for replacement of the pulmonary allograft. There was no operative mortality. One patient required reoperation for bleeding. Another had an abdominal aorta injury from use of an endoballoon clamp. There was no other major postoperative morbidity, and median postoperative hospital stay was 7.2 days (range 4-41 days). No patient required reoperation during follow-up. Twenty-four patients had acceptable pulmonary valve function, and 6 had clinically well-tolerated moderate or severe pulmonary regurgitation. Ross reversal can be performed with low morbidity and acceptable pulmonary valve function, reducing patient risk of losing 2 native valves when the autograft fails in the aortic position. Copyright © 2017 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

  4. Sensitivity and reliability of language laterality assessment with a free reversed association task - a fMRI study

    International Nuclear Information System (INIS)

    Fesl, Gunther; Brueckmann, Hartmut; Bruhns, Philipp; Rau, Sabine; Ilmberger, Josef; Wiesmann, Martin; Kegel, Gerd

    2010-01-01

    The aim of the study was to evaluate the sensitivity and reliability of assessing hemispheric language dominance with functional magnetic resonance imaging (fMRI) using a 'free reversed association task.' Thirty-nine healthy subjects (13 dextrals, 13 sinistrals and 13 bimanuals) underwent two repeated fMRI sessions. In the active phases sets of words were presented via headphones, and an associated target item was named. During the baseline phases a standard answer was given after listening to unintelligible stimuli. Data were preprocessed with SPM, and then laterality indices (LI) and reliability coefficients (RC) were calculated. Extensive frontal, temporal and parietal activations were found. Seventy-eight percent of the subjects showed left-hemispheric dominance, 5% showed right-hemispheric dominance, and 17% had bilateral language representations. The incidence of right-hemispheric language dominance was 4.3 times higher in a left-hander with a handedness quotient (HQ) of -90 than in a right-hander with a HQ of +90. The RC was 0.61 for combined ROIs (global network). Strong correlations were found between the two session LIs (r = 0.95 for the global network). 'Free reversed association' is a sensitive and reliable task for the determination of individual language lateralization. This suggests that the task may be used in a clinical setting. (orig.)

  5. Extended Islanded Reverse Sural Artery Flap for Staged Reconstruction of Foot Defects Proximal to Toes

    International Nuclear Information System (INIS)

    Yousaf, M.A.; Abidin, Z.U.; Khalid, K.; Haq, A.U.; Tarar, F.A.; Asif, M.U.; Tarar, M.N.

    2018-01-01

    To assess the outcome of extended delayed reverse sural artery flap for reconstruction of foot defects proximal to toes in terms of flap survival, complication and extended area. Study Design:Case series. Place and Duration of Study:Jinnah Burn and Reconstructive Surgery Centre, Lahore, from February 2015 to April 2017. Methodology:Cases who underwent delayed sural artery flap were inducted. Preoperative hand-held doppler was done to confirm the location of perforator. Two suitable perforators were chosen to raise the extended flap by crossing the proximal limit in all cases. The pedicle was kept minimum 3 cm wide and perfusion was assessed. Flap was delayed for one week and vaccum-assisted closure (VAC) dressing was applied over wound. The second surgery was performed after one week. Proximal perforator was clamped and ligated after checking adequate perfusion of flap. Flap was insetted into defect. Results:Thirty-two patients were reconstructed with delayed reverse sural artery flap. The mean age of the patients was 26.5 +12.2 years. Twenty-four (75%) patients were males and 8 (25%) were females. Twenty-two (68.7%) cases were degloving wounds after road traffic accidents (RTA), 6 (18.7%) were diabetic foot wounds, 4 (12.5%) sustained injury after falling from height and 7 (21.8%) patients had fracture of metatarsals. Twenty-eight flaps were transferred after one week delay, and only in 4 cases, flap were transferred after two weeks. All flaps survived completely. Complications of infection noted in 3 (9.3%) flaps, 3 (9.3%) flaps showed tip necrosis, 2 (6.2%) flaps undergone epidermolysis and only 2 (6.2%) showed venous congestion. Conclusion:Delayed islanded reverse sural artery perforator flap is a reliable and versatile option for resurfacing soft tissue defects of lower limb proximal to the toes with lesser complications and extended coverage area. (author)

  6. Extended Islanded Reverse Sural Artery flap for Staged Reconstruction of Foot Defects Proximal to Toes.

    Science.gov (United States)

    Yousaf, Muhammad Amin; Abidin, Zain Ul; Khalid, Kamran; Haq, Ata Ul; Khalid, Farrukh Aslam; Tarar, Faraz Ahmad; Asif, Muhammad Umar; Tarar, Moazzam Nazeer

    2018-02-01

    Obective:To assess the outcome of extended delayed reverse sural artery flap for reconstruction of foot defects proximal to toes in terms of flap survival, complication and extended area. Case series. Jinnah Burn and Reconstructive Surgery Centre, Lahore, from February 2015 to April 2017. Cases who underwent delayed sural artery flap were inducted. Preoperative hand-held doppler was done to confirm the location of perforator. Two suitable perforators were chosen to raise the extended flap by crossing the proximal limit in all cases. The pedicle was kept minimum 3 cm wide and perfusion was assessed. Flap was delayed for one week and vaccum-assisted closure (VAC) dressing was applied over wound. The second surgery was performed after one week. Proximal perforator was clamped and ligated after checking adequate perfusion of flap. Flap was insetted into defect. Thirty-two patients were reconstructed with delayed reverse sural artery flap. The mean age of the patients was 26.5 12.2 years. Twenty-four (75%) patients were males and 8 (25%) were females. Twenty-two (68.7%) cases were degloving wounds after road traffic accidents (RTA), 6 (18.7%) were diabetic foot wounds, 4 (12.5%) sustained injury after falling from height and 7 (21.8%) patients had fracture of metatarsals. Twenty-eight flaps were transferred after one week delay, and only in 4 cases, flap were transferred after two weeks. All flaps survived completely. Complications of infection noted in 3 (9.3%) flaps, 3 (9.3%) flaps showed tip necrosis, 2 (6.2%) flaps undergone epidermolysis and only 2 (6.2%) showed venous congestion. Delayed islanded reverse sural artery perforator flap is a reliable and versatile option for resurfacing soft tissue defects of lower limb proximal to the toes with lesser complications and extended coverage area.

  7. The Demographics of Patients with Skin Cancer who Underwent Surgery in Diyarbakır and Performed Surgical Techniques

    Directory of Open Access Journals (Sweden)

    Burhan Özalp

    2018-06-01

    Full Text Available Objective: The major factor for developing malignant skin cancers is sunlight exposure. This study aimed to evaluate the demographics of patients with skin cancers who underwent surgery in Diyarbakır where the population is exposed to more sunlight than most other Turkish cities. Methods: The medical records of patients who underwent surgery for malignant skin cancer excision between 2011 and 2016 were searched using University Hospital’s patient database program. Data about patients’ demographics, cancer features, and the surgical techniques performed were collected. Results: Over a 5-year period, 190 patients underwent surgical excision. The male to female ratio was 1.56, and the mean age was 65.8 ± 15.7 (range, 20-94 years. The most common skin cancer was basal cell carcinoma (n=138, 72.7%, followed by squamous cell carcinoma (n=45, 23.7% and malignant melanoma (n=5, 2.6%. The most common surgery was primary excision, which was performed in 90 of 190 patients (47.36%; tissue reconstruction with a skin graft or flap surgery was required for the remaining 100 (52.63%, showing a significant difference (p<0.001. Conclusion: Basal cell carcinoma is the most common skin cancer, and less than half of the patients sought treatment immediately after they recognized the lesion. The public should be educated about skin cancers to increase early diagnosis and encourage timely treatment, thereby decreasing morbidity and mortality from skin cancer.

  8. Reversible and irreversible heat engine and refrigerator cycles

    Science.gov (United States)

    Leff, Harvey S.

    2018-05-01

    Although no reversible thermodynamic cycles exist in nature, nearly all cycles covered in textbooks are reversible. This is a review, clarification, and extension of results and concepts for quasistatic, reversible and irreversible processes and cycles, intended primarily for teachers and students. Distinctions between the latter process types are explained, with emphasis on clockwise (CW) and counterclockwise (CCW) cycles. Specific examples of each are examined, including Carnot, Kelvin and Stirling cycles. For the Stirling cycle, potentially useful task-specific efficiency measures are proposed and illustrated. Whether a cycle behaves as a traditional refrigerator or heat engine can depend on whether it is reversible or irreversible. Reversible and irreversible-quasistatic CW cycles both satisfy Carnot's inequality for thermal efficiency, η ≤ η C a r n o t . Irreversible CCW cycles with two reservoirs satisfy the coefficient of performance inequality K ≤ K C a r n o t . However, an arbitrary reversible cycle satisfies K ≥ K C a r n o t when compared with a reversible Carnot cycle operating between its maximum and minimum temperatures, a potentially counterintuitive result.

  9. Designing Novel Quaternary Quantum Reversible Subtractor Circuits

    Science.gov (United States)

    Haghparast, Majid; Monfared, Asma Taheri

    2018-01-01

    Reversible logic synthesis is an important area of current research because of its ability to reduce energy dissipation. In recent years, multiple valued logic has received great attention due to its ability to reduce the width of the reversible circuit which is a main requirement in quantum technology. Subtractor circuits are between major components used in quantum computers. In this paper, we will discuss the design of a quaternary quantum reversible half subtractor circuit using quaternary 1-qudit, 2-qudit Muthukrishnan-Stroud and 3-qudit controlled gates and a 2-qudit Generalized quaternary gate. Then a design of a quaternary quantum reversible full subtractor circuit based on the quaternary half subtractor will be presenting. The designs shall then be evaluated in terms of quantum cost, constant input, garbage output, and hardware complexity. The proposed quaternary quantum reversible circuits are the first attempt in the designing of the aforementioned subtractor.

  10. Surrogate pregnancy in a patient who underwent radical hysterectomy and bilateral transposition of ovaries.

    Science.gov (United States)

    Azem, Foad; Yovel, Israel; Wagman, Israel; Kapostiansky, Rita; Lessing, Joseph B; Amit, Ami

    2003-05-01

    To evaluate IVF-surrogate pregnancy in a patient with ovarian transposition after radical hysterectomy for carcinoma of the cervix. Case report. A maternity hospital in Tel Aviv that is a major tertiary care and referral center. A 29-year-old woman who underwent Wertheim's hysterectomy for carcinoma of the uterine cervix and ovarian transposition before total pelvic irradiation. Standard IVF treatment, transabdominal oocyte retrieval, and transfer to surrogate mother. Outcome of IVF cycle. A twin pregnancy in the first cycle. This is the second reported case of controlled ovarian stimulation and oocyte retrieval performed on a transposed ovary.

  11. Time reversibility, computer simulation, algorithms, chaos

    CERN Document Server

    Hoover, William Graham

    2012-01-01

    A small army of physicists, chemists, mathematicians, and engineers has joined forces to attack a classic problem, the "reversibility paradox", with modern tools. This book describes their work from the perspective of computer simulation, emphasizing the author's approach to the problem of understanding the compatibility, and even inevitability, of the irreversible second law of thermodynamics with an underlying time-reversible mechanics. Computer simulation has made it possible to probe reversibility from a variety of directions and "chaos theory" or "nonlinear dynamics" has supplied a useful vocabulary and a set of concepts, which allow a fuller explanation of irreversibility than that available to Boltzmann or to Green, Kubo and Onsager. Clear illustration of concepts is emphasized throughout, and reinforced with a glossary of technical terms from the specialized fields which have been combined here to focus on a common theme. The book begins with a discussion, contrasting the idealized reversibility of ba...

  12. Profile of long-acting reversible contraception users in Europe.

    Science.gov (United States)

    Haimovich, Sergio

    2009-06-01

    To assess the profile of long-acting reversible contraceptives (LARCs) users in Europe. A random sample of women aged 15-49 years in 14 European countries (Germany, France, UK, Spain, Italy, Russian Federation, Estonia, Latvia, Lithuania, Austria, Czech Republic, Denmark, Norway, and Sweden) underwent web-based or computer-aided face-to-face interviews in June 2006. In this paper data pertaining to a subgroup of women using LARCs are presented. A total of 11,490 women participated in the full study. Of these, 1,188 (10%) women were LARC (hormonal implant, injectables, levonorgestrel-releasing intrauterine system [LNG-IUS], copper intrauterine device [Cu-IUD]) users. The age of the LARC users exceeded 30 years for 57-91% of them. Furthermore, more than half of them found convenience an extremely important factor when selecting the LARC as a contraceptive method. As compared to those wearing a Cu-IUD, women using hormonal LARCs experienced fewer physical and emotional symptoms that appeared or worsened during menstruation. LARCs have their place in the contraceptive market in Europe. The most popular LARCs among European women were the LNG-IUS and the Cu-IUD; both were mainly used by women who had children and had no wish to have more in the future.

  13. Ice ages and geomagnetic reversals

    Science.gov (United States)

    Wu, Patrick

    1992-01-01

    There have been speculations on the relationship between climatic cooling and polarity reversals of the earth's magnetic field during the Pleistocene. Two of the common criticisms on this relationship have been the reality of these short duration geomagnetic events and the accuracy of their dates. Champion et al. (1988) have reviewed recent progress in this area. They identified a total of 10 short-duration polarity events in the last 1 Ma and 6 of these events have been found in volcanic rocks, which also have K-Ar dates. Supposing that the speculated relationship between climatic cooling and geomagnetic reversals actually exist, two mechanisms that assume climatic cooling causes short period magnetic reversals will be investigated. These two methods are core-mantle boundary topography and transfer of the rotational energy to the core.

  14. Reverse Knowledge Transfer in MNEs

    DEFF Research Database (Denmark)

    Mudambi, Ram; Piscitello, Lucia; Rabbiosi, Larissa

    2014-01-01

    a positive correlation with the extent of reverse knowledge transfers to the parent MNE. Relying on the headquarters-subsidiary view of the MNE, we argue that, beyond a point, increasing subsidiary innovativeness will be associated with lower reverse knowledge transfers. Further, we argue......It is now well recognized that multinational enterprises (MNEs) are differentiated networks wherein subsidiaries vary in terms of their ability to create new knowledge and competencies for their parent groups. In much of this theory, it is taken for granted that subsidiary innovativeness has...... that this relationship is sensitive to the subsidiary entry mode. Using data from a sample of 293 Italian subsidiaries, we find strong support for our hypotheses. In particular, our results confirm that the effect of subsidiary innovativeness on reverse knowledge transfers displays an inverted-U shape...

  15. Dysphagia among adult patients who underwent surgery for esophageal atresia at birth.

    Science.gov (United States)

    Huynh Trudeau, Valérie; Maynard, Stéphanie; Terzic, Tatjana; Soucy, Geneviève; Bouin, Mickeal

    2015-03-01

    Clinical experiences of adults who underwent surgery for esophageal atresia at birth is limited. There is some evidence that suggests considerable long-term morbidity, partly because of dysphagia, which has been reported in up to 85% of adult patients who undergo surgery for esophageal atresia. The authors hypothesized that dysphagia in this population is caused by dysmotility and⁄or anatomical anomalies. To determine the motor and anatomical causes of dysphagia. A total of 41 adults, followed at the Esophageal Atresia Clinic at Hôpital Saint-Luc (Montreal, Quebec), were approached to particpate in the present prospective study. Evaluation was completed using upper endoscopy, manometry and barium swallow for the participants who consented. The medical charts of respondents were systematically reviewed from the neonatal period to 18 years of age to assess medical and surgical history. All 41 patients followed at the clinic consented and were included in the study. Dysphagia was present in 73% of patients. Esophagogastroduodenoscopy was performed in 32 patients: hiatal hernia was present in 62% (n=20); esophageal diverticulum in 13% (n=4); macroscopic Barrett esophagus in 31% (n=10); and esophagitis in 19% (n=6). Histological esophagitis was present in 20% and intestinal metaplasia in 10%. There were no cases of dysplagia or adenocarcinoma. Esophageal manometry was performed on 56% of the patients (n=23). Manometry revealed hypomotility in 100% of patients and included an insufficient number of peristaltic waves in 96%, nonpropagating peristalsis in 78% and low-wave amplitude in 95%. Complete aperistalsis was present in 78%. The lower esophageal sphincter was abnormal in 12 (52%) patients, with incomplete relaxation the most common anomaly. Of the 41 patients, 29 (71%) consented to a barium swallow, which was abnormal in 13 (45%). The anomalies found were short esophageal dilation in 28%, delay in esophageal emptying in 14%, diverticula in 14% and stenosis in 7

  16. Positioning paper on reversibility

    International Nuclear Information System (INIS)

    2016-01-01

    After having recalled the legal framework adopted in 2006 for the deep geological storage of radioactive wastes, and briefly introduced the concept of reversibility, this publication presents the principle of geological storage, presents high and medium level and long life wastes, highlights the ethical necessity to deal with these radioactive wastes, outlines that geological storage is the generally admitted and adopted solution at the international level, and presents additional means implemented for radioactive waste management. It presents the Cigeo project as the technical answer to the issue of radioactive waste storage, describes the Cigeo development process, its current status and its development planning, and justifies the choice of this technical solution, notably from an ethical point of view. It addresses the issue of reversibility and proposes an overview of the various tools and means which aim at guaranteeing this reversibility. Appendices propose figures illustrating the Cigeo project and its development process, and a rather detailed Power Point presentation of the project by the ANDRA (history, object, planning, installations, and so on)

  17. Magnetic islands at the field reversal surface in reversed field pinches

    International Nuclear Information System (INIS)

    Pinsker, R.I.; Reiman, A.H.

    1985-09-01

    In the reversed field pinch (RFP), magnetic field perturbations having zero poloidal mode number and any toroidal mode number are resonant at the field reversal surface. Such perturbations are a particular threat to the RFP because of their weak radial dependence at low toroidal mode number, and because the toroidal field ripple is essentially of this type. The widths of the resulting islands are calculated in this paper. The self-consistent plasma response is included through the assumption that the plasma relaxes to a Taylor force-free state. The connection with linear tearing mode theory is established for those limits where arbitrarily large islands result from infinitesimal perturbations. Toroidal effects are considered, and application of the theory to RFP experiments is discussed

  18. Reversible logic synthesis methodologies with application to quantum computing

    CERN Document Server

    Taha, Saleem Mohammed Ridha

    2016-01-01

    This book opens the door to a new interesting and ambitious world of reversible and quantum computing research. It presents the state of the art required to travel around that world safely. Top world universities, companies and government institutions  are in a race of developing new methodologies, algorithms and circuits on reversible logic, quantum logic, reversible and quantum computing and nano-technologies. In this book, twelve reversible logic synthesis methodologies are presented for the first time in a single literature with some new proposals. Also, the sequential reversible logic circuitries are discussed for the first time in a book. Reversible logic plays an important role in quantum computing. Any progress in the domain of reversible logic can be directly applied to quantum logic. One of the goals of this book is to show the application of reversible logic in quantum computing. A new implementation of wavelet and multiwavelet transforms using quantum computing is performed for this purpose. Rese...

  19. Reversible perspective and splitting in time.

    Science.gov (United States)

    Hart, Helen Schoenhals

    2012-01-01

    The element of time--the experience of it and the defensive use of it--is explored in conjunction with the use of reversible perspective as a psychotic defense. Clinical material from a long analysis illustrates how a psychotic patient used the reversible perspective, with its static splitting, to abolish the experience of time. When he improved and the reversible perspective became less effective for him, he replaced it with a more dynamic splitting mechanism using time gaps. With further improvement, the patient began to experience the passage of time, and along with it the excruciating pain of separation, envy, and loss.

  20. Refractory reverse amblyopia with atropine penalization

    Directory of Open Access Journals (Sweden)

    Preeti Ajit Patil

    2010-01-01

    Full Text Available Pharmacological penalization with atropine has been shown to be equally effective as conventional occlusion therapy in the treatment of amblyopia in children. Reverse amblyopia of the sound eye with atropine penalization has been reported before, but is more common in cases where the effect is augmented with optical penalization and is mostly reversible. We report a case of reverse amblyopia with atropine penalization, in a 4-year-old girl, which was refractory to treatment. This report highlights the need for strict monitoring of the vision in the sound eye and regular follow-up in children undergoing amblyopia treatment.

  1. Tandem mirror and field-reversed mirror experiments

    Energy Technology Data Exchange (ETDEWEB)

    Coensgen, F.H.; Simonen, T.C.; Turner, W.C.

    1979-08-21

    This paper is largely devoted to tandem mirror and field-reversed mirror experiments at the Lawrence Livermore Laboratory (LLL), and briefly summarizes results of experiments in which field-reversal has been achieved. In the tandem experiment, high-energy, high-density plasmas (nearly identical to 2XIIB plasmas) are located at each end of a solenoid where plasma ions are electrostatically confined by the high positive poentials arising in the end plug plasma. End plug ions are magnetically confined, and electrons are electrostatically confined by the overall positive potential of the system. The field-reversed mirror reactor consists of several small field-reversed mirror plasmas linked together for economic reasons. In the LLL Beta II experiment, generation of a field-reversed plasma ring will be investigated using a high-energy plasma gun with a transverse radial magnetic field. This plasma will be further heated and sustained by injection of intense, high-energy neutral beams.

  2. Estimation and uncertainty of reversible Markov models.

    Science.gov (United States)

    Trendelkamp-Schroer, Benjamin; Wu, Hao; Paul, Fabian; Noé, Frank

    2015-11-07

    Reversibility is a key concept in Markov models and master-equation models of molecular kinetics. The analysis and interpretation of the transition matrix encoding the kinetic properties of the model rely heavily on the reversibility property. The estimation of a reversible transition matrix from simulation data is, therefore, crucial to the successful application of the previously developed theory. In this work, we discuss methods for the maximum likelihood estimation of transition matrices from finite simulation data and present a new algorithm for the estimation if reversibility with respect to a given stationary vector is desired. We also develop new methods for the Bayesian posterior inference of reversible transition matrices with and without given stationary vector taking into account the need for a suitable prior distribution preserving the meta-stable features of the observed process during posterior inference. All algorithms here are implemented in the PyEMMA software--http://pyemma.org--as of version 2.0.

  3. Turn stability in beta-hairpin peptides: Investigation of peptides containing 3:5 type I G1 bulge turns.

    Science.gov (United States)

    Blandl, Tamas; Cochran, Andrea G; Skelton, Nicholas J

    2003-02-01

    The turn-forming ability of a series of three-residue sequences was investigated by substituting them into a well-characterized beta-hairpin peptide. The starting scaffold, bhpW, is a disulfide-cyclized 10-residue peptide that folds into a stable beta-hairpin with two antiparallel strands connected by a two-residue reverse turn. Substitution of the central two residues with the three-residue test sequences leads to less stable hairpins, as judged by thiol-disulfide equilibrium measurements. However, analysis of NMR parameters indicated that each molecule retains a significant folded population, and that the type of turn adopted by the three-residue sequence is the same in all cases. The solution structure of a selected peptide with a PDG turn contained an antiparallel beta-hairpin with a 3:5 type I + G1 bulge turn. Analysis of the energetic contributions of individual turn residues in the series of peptides indicates that substitution effects have significant context dependence, limiting the predictive power of individual amino acid propensities for turn formation. The most stable and least stable sequences were also substituted into a more stable disulfide-cyclized scaffold and a linear beta-hairpin scaffold. The relative stabilities remained the same, suggesting that experimental measurements in the bhpW context are a useful way to evaluate turn stability for use in protein design projects. Moreover, these scaffolds are capable of displaying a diverse set of turns, which can be exploited for the mimicry of protein loops or for generating libraries of reverse turns.

  4. Spontaneous direct and reverse osmosis

    International Nuclear Information System (INIS)

    Valitov, N.Kh.

    1996-01-01

    It has been ascertained experimentally that in the course of separation of CsCl, KCl, NaCl aqueous solutions by semi-permeable membrane from distilled water the direct and then reverse osmosis are observed. The same sequence is observed in case of separation of CsCl aqueous solutions from NaCl of different concentrations. The reason for the direct and reverse osmosis has been explained. 5 refs.; 3 figs. 1 tab

  5. Inhibition of isolated human myometrium contractility by minoxidil and reversal by glibenclamide.

    Science.gov (United States)

    Prabhakaran, S S; Dhanasekar, K R; Thomas, E; Jose, R; Peedicayil, J; Samuel, P

    2010-03-01

    This study investigated the ability of the antihypertensive drug minoxidil to inhibit potassium chloride (KCl)-induced contractility of the isolated human myometrium. Twelve strips of myometrium obtained from 12 patients who underwent hysterectomy were triggered to contract with 55 mM KCl before and after incubation with 3 concentrations (1, 3 and 10 microM) of minoxidil. The percent inhibition by minoxidil on the extent of contraction, and the area under the contractile curve of KCl-induced contraction of the myometrial strips was determined. Furthermore, the effect of 10 microM glibenclamide on the inhibition generated by 3 microM minoxidil on KCl-induced contractility was studied. It was found that minoxidil produced a concentration-dependent inhibition of KCl-induced contractility of the myometrium and that glibenclamide reversed this inhibitory effect. These results suggest that the inhibitory effect of minoxidil on isolated human myometrium contractility may prove useful in clinical conditions requiring relaxation of the myometrium. 2010 Prous Science, S.A.U. or its licensors. All rights reserved.

  6. Reversibility of continuous-variable quantum cloning

    International Nuclear Information System (INIS)

    Filip, Radim; Marek, Petr; Fiurasek, Jaromir

    2004-01-01

    We analyze a reversibility of optimal Gaussian 1→2 quantum cloning of a coherent state using only local operations on the clones and classical communication between them and propose a feasible experimental test of this feature. Performing Bell-type homodyne measurement on one clone and anticlone, an arbitrary unknown input state (not only a coherent state) can be restored in the other clone by applying appropriate local unitary displacement operation. We generalize this concept to a partial reversal of the cloning using only local operations and classical communication (LOCC) and we show that this procedure converts the symmetric cloner to an asymmetric cloner. Further, we discuss a distributed LOCC reversal in optimal 1→M Gaussian cloning of coherent states which transforms it to optimal 1→M ' cloning for M ' < M. Assuming the quantum cloning as a possible eavesdropping attack on quantum communication link, the reversibility can be utilized to improve the security of the link even after the attack

  7. Ascorbyl radical disproportionation in reverse micellar systems

    Science.gov (United States)

    Gębicki, J. L.; Szymańska-Owczarek, M.; Pacholczyk-Sienicka, B.; Jankowski, S.

    2018-04-01

    Ascorbyl radical was generated by the pulse radiolysis method and observed with the fast kinetic spectrophotometry within reverse micelles stabilized by AOT in n-heptane or by Igepal CO-520 in cyclohexane at different water to surfactant molar ratio, w0. Rate constants for the disproportionation of the ascorbyl radicals were smaller than those for intermicellar exchange for both type of reverse micelles and slower than those in homogeneous aqueous solutions. However, they increased with increasing w0 for AOT/n-heptane system, while they decreased for Igepal CO-520 system. The absorption spectra of ascorbic acid AOT/n-heptane reverse micellar system showed that the "pH" sensed by this molecule is lower than that in respective homogeneous aqueous solutions. The obtained results were rationalized taking into account three main factors (i) preferential location of ascorbic acid molecules in the interfacial region of the both types of reverse micelles; (ii) postulate that the pH of the interface is lower than that of the water pool of reverse micelles and (iii) different structure of the interface of the reverse micelles made by AOT in n-heptane and those formed by Igepal CO-520 I cyclohexane. Some possible consequences of these findings are discussed.

  8. Reverse amblyopia with atropine treatment.

    Science.gov (United States)

    Hainline, Bryan C; Sprunger, Derek C; Plager, David A; Neely, Daniel E; Guess, Matthew G

    2009-01-01

    Occlusion, pharmacologic pernalization and combined therapy have been documented in controlled studies to effectively treat amblyopia with few complications. However, there remain concerns about the effectiveness and complications when, as in this case, there are not standardized treatment protocols. A retrospective chart review of 133 consecutive patients in one community based ophthalmology practice treated for amblyopia was performed. Treatments evaluated were occlusion only, atropine penalization, and combination of occlusion and atropine. Reverse amblyopia was defined as having occured when the visual acuity of the sound eye was 3 LogMar units worse than visual acuity of the amblyopia eye after treatment. Improvement in vision after 6 months and 1 year of amblyopia therapy was similar among all three groups: 0.26 LogMar lines and 0.30 in the atropine group, 0.32 and 0.34 in the occlusion group, and 0.24 and 0.32 in the combined group. Eight (6%) patients demonstrated reverse amblyopia. The mean age of those who developed reverse amblyopia was 3.5 years, 1.5 years younger than the mean age of the study population, 7/8 had strabismic amblyopia, 6/8 were on daily atropine and had a mean refractive error of +4.77 diopters in the amblyopic eye and +5.06 diopters in the sound eye. Reverse amblyopia did not occur with occlusion only therapy. In this community based ophthalmology practice, atropine, patching, and combination therapy appear to be equally effective modalities to treat ambyopia. Highly hyperopic patients under 4 years of age with dense, strabismic amblyopia and on daily atropine appeared to be most at risk for development of reverse amblyopia.

  9. Reverse Shoulder Arthroplasty for the Treatment of Rotator Cuff Deficiency: A Concise Follow-up, at a Minimum of 10 Years, of Previous Reports.

    Science.gov (United States)

    Cuff, Derek J; Pupello, Derek R; Santoni, Brandon G; Clark, Rachel E; Frankle, Mark A

    2017-11-15

    We previously evaluated 94 patients (96 shoulders) who underwent reverse shoulder arthroplasty using a central compressive screw with 5.0-mm peripheral locking screws for baseplate fixation and a center of rotation lateral to the glenoid as treatment for end-stage rotator cuff deficiency. The purpose of this study was to report updated results at a minimum follow-up of 10 years. Forty patients (42 shoulders) were available for clinical follow-up. In the patients available for study, implant survivorship, with the end point being revision for any reason, was 90.7%. Since our 5-year report, 2 patients underwent revision surgery; 1 patient sustained a periprosthetic fracture 7 years postoperatively and 1 patient had a dislocation because of chronic shoulder instability at 8 years postoperatively. At a minimum follow-up of 10 years, the patients continued to maintain their improved outcome scores and range of motion, which were comparable with earlier follow-up evaluations. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

  10. Designing the Reverse Supply Chain

    DEFF Research Database (Denmark)

    Gobbi, Chiara

    2011-01-01

    Purpose – The purpose of this paper is to explore the impact of the product residual value (PRV) and the loss of value over time of returned products in the reverse supply chain configuration. It also examines whether or not the distinction of Fisher's functional and innovative products holds...... that allows for recapturing most of the PRV. These notions have then been tested by analyzing two reverse supply chains with a case study research methodology. Findings – The findings show that low PRV is associated with second-class recovery options (recycling and energy recovery) and that high PRV...... is associated with first-class recovery options (reconditioning and remarketing). When the recovery option is recycling, time is not relevant, the primary objective is cost reduction (efficiency), the chain is centralized, and actors and phases of the reverse chain are determined by the specificity...

  11. Flux trapping during field reversal in a field reversed theta pinch

    International Nuclear Information System (INIS)

    Milroy, R.D.; Hoffman, A.L.; Slough, J.T.; Harding, D.G.

    1983-01-01

    In this paper we present new results from both numerical and experimental studies of the formation of the conducting sheath near the tube wall and its effectiveness in trapping bias flux during field reversal

  12. Accessing 2-substituted piperidine iminosugars by organometallic addition/intramolecular reductive amination: aldehyde vs. nitrone route.

    Science.gov (United States)

    Mirabella, S; Fibbi, G; Matassini, C; Faggi, C; Goti, A; Cardona, F

    2017-11-07

    A dual synthetic strategy to afford 2-substituted trihydroxypiperidines is disclosed. The procedure involved Grignard addition either to a carbohydrate-derived aldehyde or to a nitrone derived thereof, and took advantage of an efficient ring-closure reductive amination strategy in the final cyclization step. An opposite diastereofacial preference was demonstrated in the nucleophilic attack to the two electrophiles, which would finally produce the same piperidine diastereoisomer as the major product. However, use of a suitable Lewis acid in the Grignard addition to the nitrone allowed reversing the selectivity, giving access to 2-substituted piperidines with the opposite configuration at C-2.

  13. Time-reversal symmetry breaking in quantum billiards

    Energy Technology Data Exchange (ETDEWEB)

    Schaefer, Florian

    2009-01-26

    The present doctoral thesis describes experimentally measured properties of the resonance spectra of flat microwave billiards with partially broken timereversal invariance induced by an embedded magnetized ferrite. A vector network analyzer determines the complex scattering matrix elements. The data is interpreted in terms of the scattering formalism developed in nuclear physics. At low excitation frequencies the scattering matrix displays isolated resonances. At these the effect of the ferrite on isolated resonances (singlets) and pairs of nearly degenerate resonances (doublets) is investigated. The hallmark of time-reversal symmetry breaking is the violation of reciprocity, i.e. of the symmetry of the scattering matrix. One finds that reciprocity holds in singlets; it is violated in doublets. This is modeled by an effective Hamiltonian of the resonator. A comparison of the model to the data yields time-reversal symmetry breaking matrix elements in the order of the level spacing. Their dependence on the magnetization of the ferrite is understood in terms of its magnetic properties. At higher excitation frequencies the resonances overlap and the scattering matrix elements fluctuate irregularly (Ericson fluctuations). They are analyzed in terms of correlation functions. The data are compared to three models based on random matrix theory. The model by Verbaarschot, Weidenmueller and Zirnbauer describes time-reversal invariant scattering processes. The one by Fyodorov, Savin and Sommers achieves the same for systems with complete time-reversal symmetry breaking. An extended model has been developed that accounts for partial breaking of time-reversal invariance. This extended model is in general agreement with the data, while the applicability of the other two models is limited. The cross-correlation function between forward and backward reactions determines the time-reversal symmetry breaking matrix elements of the Hamiltonian to up to 0.3 mean level spacings. Finally

  14. Time-reversal symmetry breaking in quantum billiards

    International Nuclear Information System (INIS)

    Schaefer, Florian

    2009-01-01

    The present doctoral thesis describes experimentally measured properties of the resonance spectra of flat microwave billiards with partially broken timereversal invariance induced by an embedded magnetized ferrite. A vector network analyzer determines the complex scattering matrix elements. The data is interpreted in terms of the scattering formalism developed in nuclear physics. At low excitation frequencies the scattering matrix displays isolated resonances. At these the effect of the ferrite on isolated resonances (singlets) and pairs of nearly degenerate resonances (doublets) is investigated. The hallmark of time-reversal symmetry breaking is the violation of reciprocity, i.e. of the symmetry of the scattering matrix. One finds that reciprocity holds in singlets; it is violated in doublets. This is modeled by an effective Hamiltonian of the resonator. A comparison of the model to the data yields time-reversal symmetry breaking matrix elements in the order of the level spacing. Their dependence on the magnetization of the ferrite is understood in terms of its magnetic properties. At higher excitation frequencies the resonances overlap and the scattering matrix elements fluctuate irregularly (Ericson fluctuations). They are analyzed in terms of correlation functions. The data are compared to three models based on random matrix theory. The model by Verbaarschot, Weidenmueller and Zirnbauer describes time-reversal invariant scattering processes. The one by Fyodorov, Savin and Sommers achieves the same for systems with complete time-reversal symmetry breaking. An extended model has been developed that accounts for partial breaking of time-reversal invariance. This extended model is in general agreement with the data, while the applicability of the other two models is limited. The cross-correlation function between forward and backward reactions determines the time-reversal symmetry breaking matrix elements of the Hamiltonian to up to 0.3 mean level spacings. Finally

  15. Circulating S100B and Adiponectin in Children Who Underwent Open Heart Surgery and Cardiopulmonary Bypass

    Directory of Open Access Journals (Sweden)

    Alessandro Varrica

    2015-01-01

    Full Text Available Background. S100B protein, previously proposed as a consolidated marker of brain damage in congenital heart disease (CHD newborns who underwent cardiac surgery and cardiopulmonary bypass (CPB, has been progressively abandoned due to S100B CNS extra-source such as adipose tissue. The present study investigated CHD newborns, if adipose tissue contributes significantly to S100B serum levels. Methods. We conducted a prospective study in 26 CHD infants, without preexisting neurological disorders, who underwent cardiac surgery and CPB in whom blood samples for S100B and adiponectin (ADN measurement were drawn at five perioperative time-points. Results. S100B showed a significant increase from hospital admission up to 24 h after procedure reaching its maximum peak (P0.05 have been found all along perioperative monitoring. ADN/S100B ratio pattern was identical to S100B alone with the higher peak at the end of CPB and remained higher up to 24 h from surgery. Conclusions. The present study provides evidence that, in CHD infants, S100B protein is not affected by an extra-source adipose tissue release as suggested by no changes in circulating ADN concentrations.

  16. Application of industrial CT in reverse engineering technology

    International Nuclear Information System (INIS)

    Fang Liyong; Li Hui; Bai Jinping; Li Bailin

    2013-01-01

    The basic principle and basic steps of reverse engineering technology based on industrial CT are described. The recent research progresses and situation at home and abroad of reverse engineering technology based on industrial CT image are respectively described, analyzed and summarized from two routes which are surface segmentation and volume segmentation. An example of conch is used to exhibit the results from the two routes in reverse engineering technology based on industrial CT image. Finally, some difficulties in application and the future developments of reverse engineering technology based on industrial CT are prospected. (authors)

  17. Reversible infantile mitochondrial diseases.

    Science.gov (United States)

    Boczonadi, Veronika; Bansagi, Boglarka; Horvath, Rita

    2015-05-01

    Mitochondrial diseases are usually severe and progressive conditions; however, there are rare forms that show remarkable spontaneous recoveries. Two homoplasmic mitochondrial tRNA mutations (m.14674T>C/G in mt-tRNA(Glu)) have been reported to cause severe infantile mitochondrial myopathy in the first months of life. If these patients survive the first year of life by extensive life-sustaining measures they usually recover and develop normally. Another mitochondrial disease due to deficiency of the 5-methylaminomethyl-2-thiouridylate methyltransferase (TRMU) causes severe liver failure in infancy, but similar to the reversible mitochondrial myopathy, within the first year of life these infants may also recover completely. Partial recovery has been noted in some other rare forms of mitochondrial disease due to deficiency of mitochondrial tRNA synthetases and mitochondrial tRNA modifying enzymes. Here we summarize the clinical presentation of these unique reversible mitochondrial diseases and discuss potential molecular mechanisms behind the reversibility. Understanding these mechanisms may provide the key to treatments of potential broader relevance in mitochondrial disease, where for the majority of the patients no effective treatment is currently available.

  18. Properties of the reverse transcription reaction in mRNA quantification

    DEFF Research Database (Denmark)

    Ståhlberg, Anders; Håkansson, Joakim; Xian, Xiaojie

    2004-01-01

    BACKGROUND: In most measurements of gene expression, mRNA is first reverse-transcribed into cDNA. We studied the reverse transcription reaction and its consequences for quantitative measurements of gene expression. METHODS: We used SYBR green I-based quantitative real-time PCR (QPCR) to measure...... the properties of reverse transcription reaction for the beta-tubulin, glyceraldehyde-3-phosphate dehydrogenase, Glut2, CaV1D, and insulin II genes, using random hexamers, oligo(dT), and gene-specific reverse transcription primers. RESULTS: Experimental variation in reverse transcription-QPCR (RT......-QPCR) was mainly attributable to the reverse transcription step. Reverse transcription efficiency depended on priming strategy, and the dependence was different for the five genes studied. Reverse transcription yields also depended on total RNA concentration. CONCLUSIONS: RT-QPCR gene expression measurements...

  19. C-C bond formation and related reactions at the CNC backbone in (smif)FeX (smif = 1,3-di-(2-pyridyl)-2-azaallyl): dimerizations, 3 + 2 cyclization, and nucleophilic attack; transfer hydrogenations and alkyne trimerization (X = N(TMS)2, dpma = (di-(2-pyridyl-methyl)-amide)).

    Science.gov (United States)

    Frazier, Brenda A; Williams, Valerie A; Wolczanski, Peter T; Bart, Suzanne C; Meyer, Karsten; Cundari, Thomas R; Lobkovsky, Emil B

    2013-03-18

    Molecular orbital analysis depicts the CNC(nb) backbone of the smif (1,3-di-(2-pyridyl)-2-azaallyl) ligand as having singlet diradical and/or ionic character where electrophilic or nucleophilic attack is plausible. Reversible dimerization of (smif)Fe{N(SiMe3)2} (1) to [{(Me3Si)2N}Fe]2(μ-κ(3),κ(3)-N,py2-smif,smif) (2) may be construed as diradical coupling. A proton transfer within the backbone-methylated, and o-pyridine-methylated smif of putative ((b)Me2(o)Me2smif)FeN(SiMe3)2 (8) provides a route to [{(Me3Si)2N}Fe]2(μ-κ(4),κ(4)-N,py2,C-((b)Me,(b)CH2,(o)Me2(smif)H))2 (9). A 3 + 2 cyclization of ditolyl-acetylene occurs with 1, leading to the dimer [{2,5-di(pyridin-2-yl)-3,4-di-(p-tolyl-2,5-dihydropyrrol-1-ide)}FeN(SiMe3)2]2 (11), and the collateral discovery of alkyne cyclotrimerization led to a brief study that identified Fe(N(SiMe3)2(THF) as an effective catalyst. Nucleophilic attack by (smif)2Fe (13) on (t)BuNCO and (2,6-(i)Pr2C6H3)NCO afforded (RNHCO-smif)2Fe (14a, R = (t)Bu; 14b, 2,6-(i)PrC6H3). Calculations suggested that (dpma)2Fe (15) would favorably lose dihydrogen to afford (smif)2Fe (13). H2-transfer to alkynes, olefins, imines, PhN═NPh, and ketones was explored, but only stoichiometric reactions were affected. Some physical properties of the compounds were examined, and X-ray structural studies on several dinuclear species were conducted.

  20. Telomerase reverse transcriptase mediated immortalization of human bone marrow stromal cells

    Directory of Open Access Journals (Sweden)

    Yong Teng

    2014-02-01

    Full Text Available Primary human bone marrow stromal cells (hMSCs were transfected with human telomerase reverse transcriptase (hTERT gene with lipofection method. The hTERT transfected hMSCs of passage 100 underwent chondrogenesis induction with dexamethasone, transforming the growth factor β and vitamin C, osteogenesis induction with dexamethasone, β glycerophosphoric acid and vitamin C, and cardiomyocyte induction with 5-azacytidine. After 7, 14, 21 and 28 days of induction, immunocytochemistry was performed to detect the expressions of type I and II collagen and osteocalcin, and alizarin red staining was performed to detect the bone nodule formation in osteogenesis induction. Immunocytochemistry was carried out to detect the striated muscle actin expression in cardiomyocytes. The hMSCs undergoing successful transfection were positive for the hTERT. The hTERT transfected cells were grown in vitro successfully and passaged for 136 generations. Results showed that these cells could be induced to differentiate into chondrocytes, bone and myocardial cells. Introduction of exogenous hTERT into hMSCs could achieve immortalized hMSCs with the potential of multi-directional differentiation. Thus, these cells could be applied as seed cells in tissue engineering.

  1. Wavefront reversal in a copper vapor active medium

    Energy Technology Data Exchange (ETDEWEB)

    Bunkin, F.V.; Savranskii, V.V.; Shafeev, G.A.

    1981-09-01

    Wavefront reversal in the resonator of a copper vapor laser was observed. The frequencies of the signal and reversed waves were the same. The dependence of the reversed signal power on the input signal power had a threshold. Photographs were obtained of the reconstructed image of an object when a distorting phase plate was inserted in the resonator.

  2. Application of reverse osmosis in radioactive wastewater treatment

    International Nuclear Information System (INIS)

    Kong Jinsong; Guo Weiqun

    2012-01-01

    Considering the disadvantages of the conventional evaporation and ion exchange process for radioactive wastewater treatment, the reverse osmosis is used to treat the low level radioactive wastewater. The paper summarizes the research and application progress of the reverse osmosis in the radioactive wastewater treatment and indicates that the reverse osmosis in the radioactive wastewater treatment is very important. (authors)

  3. Pattern-reversal electroretinograms in unilateral glaucoma.

    Science.gov (United States)

    Wanger, P; Persson, H E

    1983-06-01

    Pattern-reversal and flash electroretinograms (ERG) and oscillatory potentials (OP) were recorded from 11 patients with unilateral glaucoma. All glaucomatous eyes had reduced amplitudes both compared to the opposite eye in the same patient and to reference values. In 10 of the 11 cases this reduction was below the level of normal variation. The difference in pattern-reversal ERG amplitude means from glaucomatous and opposite eyes was statistically significant. No differences were observed in flash ERGs or OPs. The histopathologic correlate to the visual field defects in glaucoma is retinal ganglion cell degeneration. The present electrophysiologic findings support the view, based on results from animal experiments, that the pattern-reversal ERG reflects ganglion cell activity.

  4. Probabilistic Reversible Automata and Quantum Automata

    OpenAIRE

    Golovkins, Marats; Kravtsev, Maksim

    2002-01-01

    To study relationship between quantum finite automata and probabilistic finite automata, we introduce a notion of probabilistic reversible automata (PRA, or doubly stochastic automata). We find that there is a strong relationship between different possible models of PRA and corresponding models of quantum finite automata. We also propose a classification of reversible finite 1-way automata.

  5. Optimized 4-bit Quantum Reversible Arithmetic Logic Unit

    Science.gov (United States)

    Ayyoub, Slimani; Achour, Benslama

    2017-08-01

    Reversible logic has received a great attention in the recent years due to its ability to reduce the power dissipation. The main purposes of designing reversible logic are to decrease quantum cost, depth of the circuits and the number of garbage outputs. The arithmetic logic unit (ALU) is an important part of central processing unit (CPU) as the execution unit. This paper presents a complete design of a new reversible arithmetic logic unit (ALU) that can be part of a programmable reversible computing device such as a quantum computer. The proposed ALU based on a reversible low power control unit and small performance parameters full adder named double Peres gates. The presented ALU can produce the largest number (28) of arithmetic and logic functions and have the smallest number of quantum cost and delay compared with existing designs.

  6. Spatial reversal learning in preclinical scrapie-inoculated mice.

    Science.gov (United States)

    Lysons, A M; Woollard, S J

    1996-04-10

    Acquisition and reversal of a two-choice spatial discrimination were tested in scrapie-inoculated mice. Both acquisition and reversal were normal in mice tested 138 and 103 days prior to the onset of clinical symptoms. At 65 days before onset of clinical symptoms, scrapie-inoculated mice required more trails to criterion in reversal learning, but this effect was not significant in a second experiment (68 days preclinical) and was transient: no effect was seen 33 days before symptoms. However, the course of reversal learning was abnormal in all three late preclinical groups (68, 65 and 33 days before symptoms). Reversal learning in these three groups was characterized by a rapid extinction of the original discrimination, followed by a period, absent in controls, during which performance showed no further improvement. This effect corresponds in time of onset to the appearance of characteristic neuropathological features.

  7. Some properties of circular proteins

    International Nuclear Information System (INIS)

    Prosselkov, P.; John, P.; Dixon, N.E.; Liepinsh, E.; Williams, N.K.; University of Sydney, NSW; Matthews, J.M.; Otting, G.; Karolinska Institutet, Stockholm,

    2002-01-01

    Full text: Protein backbone cyclization can be achieved by use of a circularly-permuted split mini-intein. We have used the small N-terminal domain of the E coli DnaB helicase (DnaB-N, residues 24-136) as a model protein for cyclization because its structure has been determined both by NMR spectroscopy and X-ray crystallography, and its ends are close together. Joining of the ends of DnaB-N' via a 9-amino acid linker occurs efficiently in vivo, and the circular (cz-) protein is stabilized in comparison to the linear (Hn-) protein against thermal denaturation (ΔΔG ∼2 kcal/mol). DnaB-N exists as a dimer in the crystalline state and in solution at high concentrations. To produce linear and cyclized versions that could not dimerize, Phe102 (at the dimer interface) was changed to Glu. NMR spectra showed that the F102E mutants remained monomeric at high concentrations but otherwise had essentially the same structures as the wild-type domains. Individual rate constants for proton exchange at the amide groups in lin- and cz-DnaB-N were determined at 10 C. Although they varied as expected depending on exposure to solvent, the ratios of rates between corresponding amides in the two proteins were constant. In the same buffer, lin- and cz-DnaB-N both unfolded reversibly, with transition temperatures of 37.9 and 48.5 deg C, respectively. Correlation of the (constant) ratio of amide exchange rates with measured thermodynamic parameters suggests that amide exchange in DnaB-N occurs predominantly in a globally unfolded state. Similar studies with other proteins are underway

  8. Beneficial Effect of the Nutritional Support in Children Who Underwent Hematopoietic Stem Cell Transplant.

    Science.gov (United States)

    Koç, Nevra; Gündüz, Mehmet; Tavil, Betül; Azik, M Fatih; Coşkun, Zeynep; Yardımcı, Hülya; Uçkan, Duygu; Tunç, Bahattin

    2017-08-01

    The aim of this study was to evaluate nutritional status in children who underwent hematopoietic stem cell transplant compared with a healthy control group. A secondary aim was to utilize mid-upper arm circumference as a measure of nutritional status in these groups of children. Our study group included 40 children (18 girls, 22 boys) with mean age of 9.2 ± 4.6 years (range, 2-17 y) who underwent hematopoietic stem cell transplant. Our control group consisted of 20 healthy children (9 girls, 11 boys). The children were evaluated at admission to the hospital and followed regularly 3, 6, 9, and 12 months after discharge from the hospital. In the study group, 27 of 40 patients (67.5%) received nutritional support during hematopoietic stem cell transplant, with 15 patients (56%) receiving enteral nutrition, 6 (22%) receiving total parenteral nutrition, and 6 (22%) receiving enteral and total parenteral nutrition. Chronic malnutrition rate in the study group was 47.5% on admission to the hospital, with the control group having a rate of 20%. One year after transplant, the rate decreased to 20% in the study group and 5% in the control group. The mid-upper arm circumference was lower in children in the study group versus the control group at the beginning of the study (P groups at follow-up examinations (P > .05). During follow-up, all anthropometric measurements increased significantly in both groups. Monitoring nutritional status and initiating appropriate nutritional support improved the success of hematopoietic stem cell transplant and provided a more comfortable process during the transplant period. Furthermore, mid-upper arm circumference is a more sensitive, useful, and safer parameter that can be used to measure nutritional status of children who undergo hematopoietic stem cell transplant.

  9. Reverse Transfection Using Gold Nanoparticles

    Science.gov (United States)

    Yamada, Shigeru; Fujita, Satoshi; Uchimura, Eiichiro; Miyake, Masato; Miyake, Jun

    Reverse transfection from a solid surface has the potential to deliver genes into various types of cell and tissue more effectively than conventional methods of transfection. We present a method for reverse transfection using a gold colloid (GC) as a nanoscaffold by generating nanoclusters of the DNA/reagentcomplex on a glass surface, which could then be used for the regulation of the particle size of the complex and delivery of DNA into nuclei. With this method, we have found that the conjugation of gold nanoparticles (20 nm in particle size) to the pEGFP-N1/Jet-PEI complex resulted in an increase in the intensity of fluorescence of enhanced green fluorescent protein (EGFP) (based on the efficiency of transfection) from human mesenchymal stem cells (hMSCs), as compared with the control without GC. In this manner, we constructed a method for reverse transfection using GC to deliver genes into the cells effectively.

  10. SELECTED PROBLEMS OF REVERSE LOGISTICS IN POLAND

    OpenAIRE

    Agata Mesjasz-Lech

    2009-01-01

    This paper presents the essence of reverse logistics and directions of physical and information flows between logistic network partners. It also analyses effects of implementation of the principles of reverse logistics in Poland in the years 2004-2007

  11. Long-acting reversible hormonal contraception | Dahan-Farkas ...

    African Journals Online (AJOL)

    Long-acting reversible hormonal contraceptives are effective methods of birth control that provide contraception for an extended period without requiring user action. Long-acting reversible hormonal contraceptives include progesterone only injectables, subdermal implants and the levonorgestrel intrauterine system.

  12. Multiple Memory Structure Bit Reversal Algorithm Based on Recursive Patterns of Bit Reversal Permutation

    Directory of Open Access Journals (Sweden)

    K. K. L. B. Adikaram

    2014-01-01

    Full Text Available With the increasing demand for online/inline data processing efficient Fourier analysis becomes more and more relevant. Due to the fact that the bit reversal process requires considerable processing time of the Fast Fourier Transform (FFT algorithm, it is vital to optimize the bit reversal algorithm (BRA. This paper is to introduce an efficient BRA with multiple memory structures. In 2009, Elster showed the relation between the first and the second halves of the bit reversal permutation (BRP and stated that it may cause serious impact on cache performance of the computer, if implemented. We found exceptions, especially when the said index mapping was implemented with multiple one-dimensional memory structures instead of multidimensional or one-dimensional memory structure. Also we found a new index mapping, even after the recursive splitting of BRP into equal sized slots. The four-array and the four-vector versions of BRA with new index mapping reported 34% and 16% improvement in performance in relation to similar versions of Linear BRA of Elster which uses single one-dimensional memory structure.

  13. Sensitivity and reliability of language laterality assessment with a free reversed association task - a fMRI study

    Energy Technology Data Exchange (ETDEWEB)

    Fesl, Gunther; Brueckmann, Hartmut [University of Munich, Department of Neuroradiology, Campus Grosshadern, Marchioninistr. 15, 81377, Munich (Germany); Bruhns, Philipp [University of Munich, Department of Neuroradiology, Campus Grosshadern, Marchioninistr. 15, 81377, Munich (Germany); University of Munich, Department of Psycholinguistics, Munich (Germany); Rau, Sabine; Ilmberger, Josef [University of Munich, Department of Physical Medicine and Rehabilitation, Munich (Germany); Wiesmann, Martin [Helios Hospitals Schwerin, Department of Radiology and Neuroradiology, Schwerin (Germany); Kegel, Gerd [University of Munich, Department of Psycholinguistics, Munich (Germany)

    2010-03-15

    The aim of the study was to evaluate the sensitivity and reliability of assessing hemispheric language dominance with functional magnetic resonance imaging (fMRI) using a 'free reversed association task.' Thirty-nine healthy subjects (13 dextrals, 13 sinistrals and 13 bimanuals) underwent two repeated fMRI sessions. In the active phases sets of words were presented via headphones, and an associated target item was named. During the baseline phases a standard answer was given after listening to unintelligible stimuli. Data were preprocessed with SPM, and then laterality indices (LI) and reliability coefficients (RC) were calculated. Extensive frontal, temporal and parietal activations were found. Seventy-eight percent of the subjects showed left-hemispheric dominance, 5% showed right-hemispheric dominance, and 17% had bilateral language representations. The incidence of right-hemispheric language dominance was 4.3 times higher in a left-hander with a handedness quotient (HQ) of -90 than in a right-hander with a HQ of +90. The RC was 0.61 for combined ROIs (global network). Strong correlations were found between the two session LIs (r = 0.95 for the global network). 'Free reversed association' is a sensitive and reliable task for the determination of individual language lateralization. This suggests that the task may be used in a clinical setting. (orig.)

  14. MRI Shows that Exhaustion Syndrome Due to Chronic Occupational Stress is Associated with Partially Reversible Cerebral Changes.

    Science.gov (United States)

    Savic, I; Perski, A; Osika, W

    2018-03-01

    The present study investigates the cerebral effects of chronic occupational stress and its possible reversibility. Forty-eight patients with occupational exhaustion syndrome (29 women) and 80 controls (47 women) underwent structural magnetic resonance imaging (MRI) and neuropsychological testing. Forty-four participants (25 patients, 19 controls) also completed a second MRI scan after 1-2 years. Only patients received cognitive therapy. The stressed group at intake had reduced thickness in the right prefrontal cortex (PFC) and left superior temporal gyrus (STG), enlarged amygdala volumes, and reduced caudate volumes. Except for the caudate volume, these abnormalities were more pronounced in females. They were all related to perceived stress, which was similar for both genders. Thickness of the PFC also correlated with an impaired ability to down-modulate negative emotions. Thinning of PFC and reduction of caudate volume normalized in the follow-up. The amygdala enlargement and the left STG thinning remained. Longitudinal changes were not detected among controls. Chronic occupational stress was associated with partially reversible structural abnormalities in key regions for stress processing. These changes were dynamically correlated with the degree of perceived stress, highlighting a possible causal link. They seem more pronounced in women, and could be a substrate for an increased cerebral vulnerability to stress-related psychiatric disorders. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  15. The Role of Reverse Logistics on the European Market

    OpenAIRE

    Irina Tobosaru; Irina Nicolau

    2009-01-01

    The Council of Logistics Management has published the first definition of reverse logistics in 1992: “The term reverse logistics refers to the role of logistics in recycling waste, in the distribution and the handling of dangerous materials. A broader definition includes in the reverse logistics, activities that have the purpose of reducing the resources, of recycling, replacing, reusing the materials and relocating them”. Reverse logistics can be also defined using as standard the definition...

  16. Reversed field pinch diagnostics

    International Nuclear Information System (INIS)

    Weber, P.G.

    1986-01-01

    The Reversed Field Pinch (RFP) is a toroidal, axisymmetric magnetic confinement configuration characterized by a magnetic field configuration in which the toroidal magnetic field is of similar strength to the poloidal field, and is reversed at the edge compared to the center. The RFP routinely operates at high beta, and is a strong candidate for a compact fusion device. Relevant attributes of the configuration will be presented, together with an overview of present and planned experiments and their diagnostics. RFP diagnostics are in many ways similar to those of other magnetic confinement devices (such as tokamaks); these lectures will point out pertinent differences, and will present some diagnostics which provide special insights into unique attributes of the RFP

  17. Reversal of diabetic nephropathy by a ketogenic diet.

    Directory of Open Access Journals (Sweden)

    Michal M Poplawski

    Full Text Available Intensive insulin therapy and protein restriction delay the development of nephropathy in a variety of conditions, but few interventions are known to reverse nephropathy. Having recently observed that the ketone 3-beta-hydroxybutyric acid (3-OHB reduces molecular responses to glucose, we hypothesized that a ketogenic diet, which produces prolonged elevation of 3-OHB, may reverse pathological processes caused by diabetes. To address this hypothesis, we assessed if prolonged maintenance on a ketogenic diet would reverse nephropathy produced by diabetes. In mouse models for both Type 1 (Akita and Type 2 (db/db diabetes, diabetic nephropathy (as indicated by albuminuria was allowed to develop, then half the mice were switched to a ketogenic diet. After 8 weeks on the diet, mice were sacrificed to assess gene expression and histology. Diabetic nephropathy, as indicated by albumin/creatinine ratios as well as expression of stress-induced genes, was completely reversed by 2 months maintenance on a ketogenic diet. However, histological evidence of nephropathy was only partly reversed. These studies demonstrate that diabetic nephropathy can be reversed by a relatively simple dietary intervention. Whether reduced glucose metabolism mediates the protective effects of the ketogenic diet remains to be determined.

  18. Reversal of Diabetic Nephropathy by a Ketogenic Diet

    Science.gov (United States)

    Poplawski, Michal M.; Mastaitis, Jason W.; Isoda, Fumiko; Grosjean, Fabrizio; Zheng, Feng; Mobbs, Charles V.

    2011-01-01

    Intensive insulin therapy and protein restriction delay the development of nephropathy in a variety of conditions, but few interventions are known to reverse nephropathy. Having recently observed that the ketone 3-beta-hydroxybutyric acid (3-OHB) reduces molecular responses to glucose, we hypothesized that a ketogenic diet, which produces prolonged elevation of 3-OHB, may reverse pathological processes caused by diabetes. To address this hypothesis, we assessed if prolonged maintenance on a ketogenic diet would reverse nephropathy produced by diabetes. In mouse models for both Type 1 (Akita) and Type 2 (db/db) diabetes, diabetic nephropathy (as indicated by albuminuria) was allowed to develop, then half the mice were switched to a ketogenic diet. After 8 weeks on the diet, mice were sacrificed to assess gene expression and histology. Diabetic nephropathy, as indicated by albumin/creatinine ratios as well as expression of stress-induced genes, was completely reversed by 2 months maintenance on a ketogenic diet. However, histological evidence of nephropathy was only partly reversed. These studies demonstrate that diabetic nephropathy can be reversed by a relatively simple dietary intervention. Whether reduced glucose metabolism mediates the protective effects of the ketogenic diet remains to be determined. PMID:21533091

  19. Reversible logic gates on Physarum Polycephalum

    International Nuclear Information System (INIS)

    Schumann, Andrew

    2015-01-01

    In this paper, we consider possibilities how to implement asynchronous sequential logic gates and quantum-style reversible logic gates on Physarum polycephalum motions. We show that in asynchronous sequential logic gates we can erase information because of uncertainty in the direction of plasmodium propagation. Therefore quantum-style reversible logic gates are more preferable for designing logic circuits on Physarum polycephalum

  20. Observation of the reversed current effect

    International Nuclear Information System (INIS)

    Jones, I.R.; Silawatshananai, C.

    1979-05-01

    The paper describes an observation of the reversed current effect, and its consequences, in a 'stabilized' Z-pinch. Magnetic probe measurements and holographic interferometry were used to follow the development of a reversed current layer and to pinpoint its location in the outer region of the pinched plasma column. The subsequent ejection of the outer plasma layer was observed using fast photography

  1. Call-Fleming Syndrome (Reversible Cerebral Artery Vasoconstriction and Aneurysm Associated with Multiple Recreational Drug Use

    Directory of Open Access Journals (Sweden)

    Doniel Drazin

    2013-01-01

    Full Text Available Drug abuse represents a significant health issue. Evidence suggests that recreational drug use has a direct effect on the cerebral vasculature and is of greater concern in those with undiagnosed aneurysms or vascular malformations. The authors report a case of thunderclap headache with a negative head CT and equivocal lumbar puncture after a drug-fueled weekend. The patient underwent diagnostic cerebral angiogram which demonstrated multisegmental, distal areas of focal narrowing of the middle, anterior, posterior, and posterior inferior cerebral artery and an incidental aneurysm. It is often difficult to determine the exact origin of symptoms; thus we were left with a bit of a chicken or the egg debate, trying to decipher which part came first. Either the aneurysm ruptured with associated concomitant vasospasm or it is a case of Call-Fleming syndrome (reversible cerebral artery vasoconstriction with an incidental aneurysm. The authors proposed their management and rationale of this complex case.

  2. Boiler feedwater treatment using reverse osmosis at Suncor OSG

    International Nuclear Information System (INIS)

    Brown, T.

    1997-01-01

    The installation of a new 1000 cu m/hr reverse osmosis water treatment system for boiler feedwater at a Suncor plant was discussed. The selection process began in 1993 when Suncor identified a need to increase its boiler feedwater capacity. The company reviewed many options available to increase the treated water capacity. These included: contracting the supply of treated water, adding additional capacity, replacing the entire plant, reverse osmosis, and demineralization. The eventual decision was to build a new 1000 cu m/hr reverse osmosis water treatment plant with the following key components: a Degremont Infilco Ultra Pulsator Clarifier and a Glegg Water Conditioning multimedia filter, Amberpack softeners and reverse osmosis arrays. The reverse osmosis plant was environmentally favourable over an equivalent demineralization plant. A technical comparison was provided between demineralization and reverse osmosis. The system has proven to be successful and economical in meeting the plants needs. 5 figs

  3. Factors affecting timing of closure and non-reversal of temporary ileostomies.

    Science.gov (United States)

    Sier, M F; van Gelder, L; Ubbink, D T; Bemelman, W A; Oostenbroek, R J

    2015-09-01

    Although stoma closure is considered a simple surgical intervention, the interval between construction and reversal is often prolonged, and some ileostomies may never be reversed. We evaluated possible predictors for non-reversal and prolonged interval between construction and reversal. In a cohort study of ileostomy patients treated in a large teaching hospital, we collected data from the surgical complication and enterostomal therapists' registries between January 2001 and December 2011. Parameters responsible for morbidity, mortality, length of stay and time interval between construction and reversal were analysed. Of 485 intentionally temporary ileostomies, 359 were reversed after a median of 5.6 months (IQR 3.8-8.9 months), while 126 (26%) remained permanent. End ileostomy and intra-abdominal abscess independently delayed reversal. Age, end ileostomy, higher body mass index and preoperative radiotherapy were independent factors for non-reversal. Median duration of hospitalisation for reversal was 7.0 days (5-13 days). Morbidity and mortality were 31 and 0.9%, respectively. In 20 patients (5.5%), re-ileostomy was necessary. A substantial number of ileostomies that are intended to be temporary will never be reversed. If reversed, the interval between construction and reversal is longer than anticipated, while morbidity after reversal and duration of hospitalisation are considerable. Besides a temporary ileostomy, there are two other options: no diversion or a permanent colostomy. Shared decision-making is to be preferred in these situations.

  4. A model for 'reverse innovation' in health care.

    Science.gov (United States)

    Depasse, Jacqueline W; Lee, Patrick T

    2013-08-30

    'Reverse innovation,' a principle well established in the business world, describes the flow of ideas from emerging to more developed economies. There is strong and growing interest in applying this concept to health care, yet there is currently no framework for describing the stages of reverse innovation or identifying opportunities to accelerate the development process. This paper combines the business concept of reverse innovation with diffusion of innovation theory to propose a model for reverse innovation as a way to innovate in health care. Our model includes the following steps: (1) identifying a problem common to lower- and higher-income countries; (2) innovation and spread in the low-income country (LIC); (3) crossover to the higher-income country (HIC); and (4) innovation and spread in the HIC. The crucial populations in this pathway, drawing from diffusion of innovation theory, are LIC innovators, LIC early adopters, and HIC innovators. We illustrate the model with three examples of current reverse innovations. We then propose four sets of specific actions that forward-looking policymakers, entrepreneurs, health system leaders, and researchers may take to accelerate the movement of promising solutions through the reverse innovation pipeline: (1) identify high-priority problems shared by HICs and LICs; (2) create slack for change, especially for LIC innovators, LIC early adopters, and HIC innovators; (3) create spannable social distances between LIC early adopters and HIC innovators; and (4) measure reverse innovation activity globally.

  5. Reversible airfoils for stopped rotors in high speed flight

    International Nuclear Information System (INIS)

    Niemiec, Robert; Jacobellis, George; Gandhi, Farhan

    2014-01-01

    This study starts with the design of a reversible airfoil rib for stopped-rotor applications, where the sharp trailing-edge morphs into the rounded leading-edge, and vice-versa. A NACA0012 airfoil is approximated in a piecewise linear manner and straight, rigid outer profile links used to define the airfoil contour. The end points of the profile links connect to control links, each set on a central actuation rod via an offset. Chordwise motion of the actuation rod moves the control and the profile links and reverses the airfoil. The paper describes the design methodology and evolution of the final design, based on which two reversible airfoil ribs were fabricated and used to assemble a finite span reversible rotor/wing demonstrator. The profile links were connected by Aluminum strips running in the spanwise direction which provided stiffness as well as support for a pre-tensioned elastomeric skin. An inter-rib connector with a curved-front nose piece supports the leading-edge. The model functioned well and was able to reverse smoothly back-and-forth, on application and reversal of a voltage to the motor. Navier–Stokes CFD simulations (using the TURNS code) show that the drag coefficient of the reversible airfoil (which had a 13% maximum thickness due to the thickness of the profile links) was comparable to that of the NACA0013 airfoil. The drag of a 16% thick elliptical airfoil was, on average, about twice as large, while that of a NACA0012 in reverse flow was 4–5 times as large, even prior to stall. The maximum lift coefficient of the reversible airfoil was lower than the elliptical airfoil, but higher than the NACA0012 in reverse flow operation. (paper)

  6. Online Reverse Auctions for Procurement of Services

    NARCIS (Netherlands)

    U.L. Radkevitch (Uladzimir)

    2008-01-01

    textabstractOnline reverse auctions, in which a buyer seeks to select a supplier and suppliers compete for contracts by bidding online, revolutionized corporate procurement early this century. Shortly after they had been pioneered by General Electric, many companies rushed to adopt reverse auctions

  7. Medical abortion reversal: science and politics meet.

    Science.gov (United States)

    Bhatti, Khadijah Z; Nguyen, Antoinette T; Stuart, Gretchen S

    2018-03-01

    Medical abortion is a safe, effective, and acceptable option for patients seeking an early nonsurgical abortion. In 2014, medical abortion accounted for nearly one third (31%) of all abortions performed in the United States. State-level attempts to restrict reproductive and sexual health have recently included bills that require physicians to inform women that a medical abortion is reversible. In this commentary, we will review the history, current evidence-based regimen, and regulation of medical abortion. We will then examine current proposed and existing abortion reversal legislation. The objective of this commentary is to ensure physicians are armed with rigorous evidence to inform patients, communities, and policy makers about the safety of medical abortion. Furthermore, given the current paucity of evidence for medical abortion reversal, physicians and policy makers can dispel bad science and misinformation and advocate against medical abortion reversal legislation. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Reverse micelles as a tool for probing solvent modulation of protein dynamics: Reverse micelle encapsulated hemoglobin☆

    OpenAIRE

    Roche, Camille J.; Dantsker, David; Heller, Elizabeth R.; Sabat, Joseph E.; Friedman, Joel M.

    2013-01-01

    Hydration waters impact protein dynamics. Dissecting the interplay between hydration waters and dynamics requires a protein that manifests a broad range of dynamics. Proteins in reverse micelles (RMs) have promise as tools to achieve this objective because the water content can be manipulated. Hemoglobin is an appropriate tool with which to probe hydration effects. We describe both a protocol for hemoglobin encapsulation in reverse micelles and a facile method using PEG and cosolvents to mani...

  9. Cu-64-labeled lactam bridge-cyclized α-MSH peptides for PET imaging of melanoma.

    Science.gov (United States)

    Guo, Haixun; Miao, Yubin

    2012-08-06

    The purpose of this study was to examine and compare the melanoma targeting and imaging properties of (64)Cu-NOTA-GGNle-CycMSH(hex) {(64)Cu-1,4,7-triazacyclononane-1,4,7-triacetic acid-Gly-Gly-Nle-c[Asp-His-DPhe-Arg-Trp-Lys]-CONH2} and (64)Cu-DOTA-GGNle-CycMSH(hex) {(64)Cu-1,4,7,10-tetraazacyclononane-1,4,7,10-tetraacetic acid-GGNle-CycMSH(hex)}. Two lactam bridge-cyclized peptides, NOTA-GGNle-CycMSH(hex) and DOTA-GGNle-CycMSH(hex), were synthesized using fluorenylmethyloxy carbonyl (Fmoc) chemistry. The melanocortin-1 (MC1) receptor binding affinity of NOTA-GGNle-CycMSH(hex) was determined in B16/F1 melanoma cells and compared with DOTA-GGNle-CycMSH(hex). The melanoma targeting and imaging properties of (64)Cu-NOTA-GGNle-CycMSH(hex) and (64)Cu-DOTA-GGNle-CycMSH(hex) were determined in B16/F1 melanoma-bearing C57 mice. NOTA-GGNle-CycMSH(hex) and DOTA-GGNle-CycMSH(hex) displayed comparable MC1 receptor binding affinities (1.6 vs 2.1 nM). The substitution of DOTA with NOTA dramatically increased the melanoma uptake and decreased the renal and liver uptake of (64)Cu-NOTA-GGNle-CycMSH(hex). The tumor uptake of (64)Cu-NOTA-GGNle-CycMSH(hex) was between 12.39 ± 1.61 and 12.71 ± 2.68% ID/g at 0.5, 2, and 4 h postinjection. The accumulation of (64)Cu-NOTA-GGNle-CycMSH(hex) activity in normal organs was lower than 1.02% ID/g except for the kidneys 2, 4, and 24 h postinjection. The tumor/liver uptake ratios of (64)Cu-NOTA-GGNle-CycMSHhex were 17.96, 16.95, and 8.02, whereas the tumor/kidney uptake ratios of (64)Cu-NOTA-GGNle-CycMSH(hex) were 2.52, 3.60, and 5.74 at 2, 4, and 24 h postinjection, respectively. Greater than 91% of the injected radioactivity cleared through the urinary system by 2 h postinjection. The substitution of DOTA with NOTA resulted in a dramatic increase in melanoma uptake and decrease in renal and liver uptake of (64)Cu-NOTA-GGNle-CycMSH(hex) as compared to (64)Cu-DOTA-GGNle-CycMSH(hex). High melanoma uptake coupled with low accumulation in nontarget

  10. Dynamical similarity of geomagnetic field reversals.

    Science.gov (United States)

    Valet, Jean-Pierre; Fournier, Alexandre; Courtillot, Vincent; Herrero-Bervera, Emilio

    2012-10-04

    No consensus has been reached so far on the properties of the geomagnetic field during reversals or on the main features that might reveal its dynamics. A main characteristic of the reversing field is a large decrease in the axial dipole and the dominant role of non-dipole components. Other features strongly depend on whether they are derived from sedimentary or volcanic records. Only thermal remanent magnetization of lava flows can capture faithful records of a rapidly varying non-dipole field, but, because of episodic volcanic activity, sequences of overlying flows yield incomplete records. Here we show that the ten most detailed volcanic records of reversals can be matched in a very satisfactory way, under the assumption of a common duration, revealing common dynamical characteristics. We infer that the reversal process has remained unchanged, with the same time constants and durations, at least since 180 million years ago. We propose that the reversing field is characterized by three successive phases: a precursory event, a 180° polarity switch and a rebound. The first and third phases reflect the emergence of the non-dipole field with large-amplitude secular variation. They are rarely both recorded at the same site owing to the rapidly changing field geometry and last for less than 2,500 years. The actual transit between the two polarities does not last longer than 1,000 years and might therefore result from mechanisms other than those governing normal secular variation. Such changes are too brief to be accurately recorded by most sediments.

  11. Marburg Virus Reverse Genetics Systems

    Directory of Open Access Journals (Sweden)

    Kristina Maria Schmidt

    2016-06-01

    Full Text Available The highly pathogenic Marburg virus (MARV is a member of the Filoviridae family and belongs to the group of nonsegmented negative-strand RNA viruses. Reverse genetics systems established for MARV have been used to study various aspects of the viral replication cycle, analyze host responses, image viral infection, and screen for antivirals. This article provides an overview of the currently established MARV reverse genetic systems based on minigenomes, infectious virus-like particles and full-length clones, and the research that has been conducted using these systems.

  12. Reference counting for reversible languages

    DEFF Research Database (Denmark)

    Mogensen, Torben Ægidius

    2014-01-01

    inverses: Freeing a block of memory is done by running the allocation procedure backwards. Axelsen and Glück use this heap manager to sketch implementation of a simple reversible functional language where pattern matching a constructor is the inverse of construction, so pattern-matching implies......Modern programming languages and operating systems use heap memory that allows allocation and deallocation of memory to be decoupled, so they don't follow a stack discipline. Axelsen and Glück have presented a reversible heap manager where allocation and deallocation are each other's logical...

  13. REVERSIBLE VENTILATION SYSTEM FOR ADMINISTRATIVE BUILDINGS

    Directory of Open Access Journals (Sweden)

    Valery Yu. Kravchuk

    2017-01-01

    Full Text Available Abstract. Objectives To consider the possibility of applying the principle of reversing air flows for a centralised ventilation system; to develop a specific scheme for air exchange reversible ventilation, which will take into account the peculiarities of the microclimate of administrative buildings; to select the type of filling of the air-permeable element and justify this choice; to determine the conditions for changing the direction of air movement in the ventilation system and the area of its application; to form a list of equipment necessary for the operation of such a system; to consider the influence of supply and exhaust devices on the heat and humidity regime of claddings. Methods  To achieve this goal, the published thematic material was reviewed and a patent search carried out using Russian and European databases. Data on mathematical modelling of filtration in porous media and experimental results were used. A method for ventilating rooms in administrative building using the reversal of movement of supply and exhaust air streams along the same channels was applied. Results  Schemas for reversible ventilation systems are presented and their modes of operation considered. It is established that the idea of reversing ventilation flows has not yet been applied in the development of centralised ventilation systems. Based on these published materials, it was concluded that the proposed design of supply and exhaust devices can be used in practice. An original air exchange scheme for the ventilation of administrative buildings and design of supply and exhaust devices for this system are proposed. The conditions for changing the operating modes of the system and the scope of its application are determined. Conclusion The use of the proposed ventilation system allows normative air exchange to be provided without using a supply unit during the cold season. This application of airflow reversal allows the potential of natural forces to be used

  14. Field reversed theta pinch TC-I UNICAMP

    International Nuclear Information System (INIS)

    Honda, R.Y.; Machida, M.; Aramaki, E.A.; Porto, P.; Berni, L.A.

    1990-01-01

    Field reversed configuration TC-I device is 16 cm diameter, 1 meter long with two mirror coils and 30 kJ field reversed theta pinch working for over two years at University of Campinas. Its implosion dynamics and field reversal parameters have been studied using flux excluded loops, internal magnetic probe, visible spectroscopy, photodiode array and image converter camera. The vacuum vessel is a pyrex tube of 14,5 cm diameter pumped with a liquid nitrogen cooled diffusion pump to a base pressure of 6 x 10 -7 Torr. The schematic view of the machine and experimental set up are shown. (Author)

  15. Reverse logistics in the Brazilian construction industry.

    Science.gov (United States)

    Nunes, K R A; Mahler, C F; Valle, R A

    2009-09-01

    In Brazil most Construction and Demolition Waste (C&D waste) is not recycled. This situation is expected to change significantly, since new federal regulations oblige municipalities to create and implement sustainable C&D waste management plans which assign an important role to recycling activities. The recycling organizational network and its flows and components are fundamental to C&D waste recycling feasibility. Organizational networks, flows and components involve reverse logistics. The aim of this work is to introduce the concepts of reverse logistics and reverse distribution channel networks and to study the Brazilian C&D waste case.

  16. Performance of the reverse Helmbold universal portfolio

    Science.gov (United States)

    Tan, Choon Peng; Kuang, Kee Seng; Lee, Yap Jia

    2017-04-01

    The universal portfolio is an important investment strategy in a stock market where no stochastic model is assumed for the stock prices. The zero-gradient set of the objective function estimating the next-day portfolio which contains the reverse Kullback-Leibler order-alpha divergence is considered. From the zero-gradient set, the explicit, reverse Helmbold universal portfolio is obtained. The performance of the explicit, reverse Helmbold universal portfolio is studied by running them on some stock-price data sets from the local stock exchange. It is possible to increase the wealth of the investor by using these portfolios in investment.

  17. The Effects of Passive Cigarette Smoke Exposure on the Survival of the Reverse Sural Fasciocutaneous Flap.

    Science.gov (United States)

    Sadagatullah, Abdul Nawfar; Halim, Ahmad Sukari; Bathusha, Mohd Shakir; Ramachandran, Anantha Kumar

    2017-12-01

    Background  The possibility of a person who had undergone surgery to be exposed to the ill effects of cigarette smoke is high, more so if the person lives with a smoker. With increasing popularity of reverse sural fasciocutaneous flaps, a surgeon may have to manage a person who lives with a smoker or is exposed to cigarette smoke. A clear understanding of the effects of exposure to cigarette smoke on reverse sural fasciocutaneous flaps is necessary. This study was performed to establish a clearer understanding of the effects of smoking on reverse sural fasciocutaneous flaps and evidence for preoperative patient counseling about smoking and smoke exposure. Objective  The study investigated effects of exposure to cigarette smoke on the survival of the reverse sural fasciocutaneous flap. Methods  This was an experimental observational study conducted at the Laboratory for Animal Research Unit in the Health Campus of Universiti Sains Malaysia. Twelve adult White New Zealand rabbits ( Oryctolagus cuniculus ) were divided into two groups of six. All 12 rabbits had a 2.5- × 2.5-cm reverse sural fasciocutaneous flap raised on both its hind limbs. The group exposed to cigarette smoke underwent 4 weeks of smoke exposure for 2 hours daily prior to surgery. This was then continued until analysis of the results. The control group had no intervention. All flaps were analyzed on the seventh postoperative day, after tracing on transparent plastic sheets with the necrotic area marked followed by 2D planimetry done on a grid paper. The flaps were assessed on the total flap area and survival area percentage. It was recorded as mean ± SD. The presence or absence of infection and hematoma was also noted. Results  Twelve flaps were analyzed in each group. Total mean flap area and survival area percentage of the control group were 120.33 ± 31.03 mm 2 and 80.12 ± 15.75%, respectively, whereas in the cigarette smoke-exposed group, it was 121.83 ± 17.93 mm 2

  18. Transitional paleointensities from Kauai, Hawaii, and geomagnetic reversal models

    Science.gov (United States)

    Bogue, Scott W.; Coe, Robert S.

    1984-01-01

    Previously presented paleointensity results from an R-N transition zone in Kauai, Hawaii, show that field intensity dropped from 0. 431 Oe to 0. 101 Oe while the field remained within 30 degree of the reversed axial dipole direction. A recovery in intensity and the main directional change followed this presumably short period of low field strength. As the reversal neared completion, the field has an intensity of 0. 217 Oe while still 40 degree from the final direction. The relationship of paleointensity to field direction during the early part of the reversal thus differs from that toward the end, a feature that only some reversal models are consistent with. For example, a model in which a standing nondipole component persists through the dipole reversal predicts only symmetric intensity patterns. In contrast, zonal flooding models generate suitably complex field behavior if multiple flooding schemes operate during a single reversal or if the flooding process is itself asymmetric.

  19. Decision-making on reverse logistics in the construction industry

    Directory of Open Access Journals (Sweden)

    Thanwadee Chinda

    2016-02-01

    Full Text Available With the growing competition, many construction organizations attempt to improve their productivity, quality, and efficiency. Construction waste management, by means of reverse logistics, becomes a key issue to improve the productivity, and raise the company’s green image. In this study, four reverse logistics methods-direct reuse, remanufacturing, recycling, and landfill-are considered to manage construction and demolition (C&D waste. Two factors (economic and site-specific with their 15 sub-factors affecting the decisions to implement the reverse logistics are examined. The hierarchy model of reverse logistics decisions, developed through the analytic hierarchy process, reveal the importance of the economic factor over the site-specific factor. It is suggested that the transportation cost, the processing cost, the specific sorting technology, and the limited project time must be first considered before making decisions on reverse logistics plans. The construction company can utilize the developed hierarchy model to decide on the most appropriate reverse logistics plan to achieve the best benefits.

  20. LV reverse remodeling imparted by aortic valve replacement for severe aortic stenosis; is it durable? A cardiovascular MRI study sponsored by the American Heart Association

    Directory of Open Access Journals (Sweden)

    Caruppannan Ketheswaram

    2011-04-01

    Full Text Available Abstract Background In patients with severe aortic stenosis (AS, long-term data tracking surgically induced effects of afterload reduction on reverse LV remodeling are not available. Echocardiographic data is available short term, but in limited fashion beyond one year. Cardiovascular MRI (CMR offers the ability to serially track changes in LV metrics with small numbers due to its inherent high spatial resolution and low variability. Hypothesis We hypothesize that changes in LV structure and function following aortic valve replacement (AVR are detectable by CMR and once triggered by AVR, continue for an extended period. Methods Tweny-four patients of which ten (67 ± 12 years, 6 female with severe, but compensated AS underwent CMR pre-AVR, 6 months, 1 year and up to 4 years post-AVR. 3D LV mass index, volumetrics, LV geometry, and EF were measured. Results All patients survived AVR and underwent CMR 4 serial CMR's. LVMI markedly decreased by 6 months (157 ± 42 to 134 ± 32 g/m2, p 2. Similarly, EF increased pre to post-AVR (55 ± 22 to 65 ± 11%,(p 2. LV stroke volume increased rapidly from pre to post-AVR (40 ± 11 to 44 ± 7 ml, p Conclusion After initial beneficial effects imparted by AVR in severe AS patients, there are, as expected, marked improvements in LV reverse remodeling. Via CMR, surgically induced benefits to LV structure and function are durable and, unexpectedly express continued, albeit markedly incomplete improvement through 4 years post-AVR concordant with sustained improved clinical status. This supports down-regulation of both mRNA and MMP activity acutely with robust suppression long term.

  1. Encoding changes in orbitofrontal cortex in reversal-impaired aged rats.

    Science.gov (United States)

    Schoenbaum, Geoffrey; Setlow, Barry; Saddoris, Michael P; Gallagher, Michela

    2006-03-01

    Previous work in rats and primates has shown that normal aging can be associated with a decline in cognitive flexibility mediated by prefrontal circuits. For example, aged rats are impaired in rapid reversal learning, which in young rats depends critically on the orbitofrontal cortex. To assess whether aging-related reversal impairments reflect orbitofrontal dysfunction, we identified aged rats with reversal learning deficits and then recorded single units as these rats, along with unimpaired aged cohorts and young control rats, learned and reversed a series of odor discrimination problems. We found that the flexibility of neural correlates in orbitofrontal cortex was markedly diminished in aged rats characterized as reversal-impaired in initial training. In particular, although many cue-selective neurons in young and aged-unimpaired rats reversed odor preference when the odor-outcome associations were reversed, cue-selective neurons in reversal-impaired aged rats did not. In addition, outcome-expectant neurons in aged-impaired rats failed to become active during cue sampling after learning. These altered features of neural encoding could provide a basis for cognitive inflexibility associated with normal aging.

  2. Reversibility and social sciences. Proceedings of the 2008 October 2 Symposium

    International Nuclear Information System (INIS)

    2008-01-01

    The contributions of this symposium are related to the gradual appropriation of the notion of storage reversibility by the ANDRA, the definition of waste reversible storage, the stage by stage management and the decision process, the reversibility from an economic point of view, the storage reversibility and safety, how to show and demonstrate the reversibility, the storage observation-surveillance, economic implications of the implementation of the notion of reversibility. Each of these interventions is followed by a debate

  3. Posterior Reversible Encephalopathy (PRES)

    International Nuclear Information System (INIS)

    Moron E, Fanny E; Diaz Marchan, Pedro

    2005-01-01

    The Posterior Reversible Encephalopathy Syndrome (PRES) is a clinical Syndrome composed of cephalea, alteration in vision and convulsions, usually observed in patients with sudden elevation of arterial pressure. The imagenologic evidence shows reversible vasogenic brain edema without stroke. Its location is predominantly posterior; it affects the cortex and the subcortical white matter of the occipital, parietal and temporal lobes. The treatment with antihypertensive drugs and the removing of immunosupressor medication are generally associated with complete neurological recovery; this is reflected also in the images which return to their basal condition. The untreated hypertension, on the other side, can result in a progressive defect of the autoregulation system of the central nervous system with cerebral hemorrhage, irreversible brain stroke, coma and death

  4. Microscopic reversibility and the information contained in the composition vector

    CERN Document Server

    Luetich, J J

    2001-01-01

    The microscopic level of observation is the level where every (hypothetical) transformation is reversible. As during reversible processes no composition information is generated by the system, when transforming composition variables, microscopic reversibility is the other side of the coin. This paper is the fourth member of a tetralogy conceived to give insight into the concept of microscopic reversibility.

  5. Reverse logistics: A review of case studies

    NARCIS (Netherlands)

    Brito, de M.P.; Dekker, Rommert; Flapper, S.D.P.; Fleischmann, B.; Klose, A.

    2004-01-01

    This paper gives an overview of scientific literature that describes and discusses cases of reverse logistics activities in practice. Over sixty case studies are considered. Based on these studies we are able to indicate critical factors for the practice of reverse logistics. In addition we compare

  6. Vibrational dynamics of ice in reverse micelles

    NARCIS (Netherlands)

    Dokter, A.M.; Petersen, C.; Woutersen, S.; Bakker, H.J.

    2008-01-01

    he ultrafast vibrational dynamics of HDO:D2O ice at 180 K in anionic reverse micelles is studied by midinfrared femtosecond pump-probe spectroscopy. Solutions containing reverse micelles are cooled to low temperatures by a fast-freezing procedure. The heating dynamics of the micellar solutions is

  7. Mechanistic switch in dual gold catalysis of diynes: C(sp(3))-H activation through bifurcation--vinylidene versus carbene pathways.

    Science.gov (United States)

    Hansmann, Max M; Rudolph, Matthias; Rominger, Frank; Hashmi, A Stephen K

    2013-02-25

    The other side of the mountain: Changing the framework of diyne systems opens up new cyclization modes for dual gold catalysis. Instead of a 5-endo cyclization and gold vinylidenes a 6-endo cyclization gives rise to gold-stabilized carbenes as key intermediates for selective C-H insertions. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Magnetization reversal mechanisms under oblique magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Ntallis, N.; Efthimiadis, K.G., E-mail: kge@auth.gr

    2017-03-01

    In this work finite element micromagnetic simulations were performed in order to study the reversal mechanisms of spherical ferromagnetic particles with uniaxial magnetocrystalline anisotropy, when they are magnetized along an oblique direction with respect to the anisotropy axis. Magnetization loops are taken in different directions of external magnetic field, at different anisotropy constants and particle sizes. In the simulation results, the three reversal mechanisms (coherent, curling and domains) are observed and new phenomena arise due to the action of oblique magnetic fields. Moreover, the dependence of the critical fields with respect to the angle of the external field is presented. - Highlights: • Finite element micromagnetic simulation of the three different reversal mechanisms. • For the curling mechanism, the new phenomenon is the rotation of the vortex. • In the domain reversal mechanism, the formed domain wall is smaller than 180°. • In soft ferromagnetic particles a rearrangement of the magnetic domains is observed.

  9. Survey of methods for rapid spin reversal

    International Nuclear Information System (INIS)

    McKibben, J.L.

    1980-01-01

    The need for rapid spin reversal technique in polarization experiments is discussed. The ground-state atomic-beam source equipped with two rf transitions for hydrogen can be reversed rapidly, and is now in use on several accelerators. It is the optimum choice provided the accelerator can accept H + ions. At present all rapid reversal experiments using H - ions are done with Lamb-shift sources; however, this is not a unique choice. Three methods for the reversal of the spin of the atomic beam within the Lamb-shift source are discussed in order of development. Coherent intensity and perhaps focus modulation seem to be the biggest problems in both types of sources. Methods for reducing these modulations in the Lamb-shift source are discussed. The same Lamb-shift apparatus is easily modified to provide information on the atomic physics of quenching of the 2S/sub 1/2/ states versus spin orientation, and this is also discussed. 2 figures

  10. Reverse Logistics: RFID the key to optimality

    Directory of Open Access Journals (Sweden)

    Rezwan Asif

    2011-07-01

    Full Text Available Purpose: The purpose of this paper is to find ways to reduce uncertainties in Reverse logistic supply chain (RLSC through the use of Radio-frequency identification (RFID technology.Design/methodology/approach: This paper reviews literature and builds model to relate RFID with uncertainties in order to optimize Reverse Logistics. Findings: RFID is really efficient to determine and detect quantity, variety and cycle times of returns; however it's not as convenient to determine quality of the returns. The collected information from RFID can be used to standardize the RLSC.Research limitations: Though it’s several and unique advantages some limitations of RFID have been identified in quality and processing sequence, collecting points and different standards, and in global usage.Originality/value: Previous studies in the area of Reverse Logistics and RFID don’t cover all impacts of this technology on RLSC. This review paper has investigated these impacts and offers a model for optimizing the Reverse Logistics Supply Chain.

  11. Elastic least-squares reverse time migration

    KAUST Repository

    Feng, Zongcai; Schuster, Gerard T.

    2016-01-01

    Elastic least-squares reverse time migration (LSRTM) is used to invert synthetic particle-velocity data and crosswell pressure field data. The migration images consist of both the P- and Svelocity perturbation images. Numerical tests on synthetic and field data illustrate the advantages of elastic LSRTM over elastic reverse time migration (RTM). In addition, elastic LSRTM images are better focused and have better reflector continuity than do the acoustic LSRTM images.

  12. Boosting reversible pushdown machines by preprocessing

    DEFF Research Database (Denmark)

    Axelsen, Holger Bock; Kutrib, Martin; Malcher, Andreas

    2016-01-01

    languages, whereas for reversible pushdown automata the accepted family of languages lies strictly in between the reversible deterministic context-free languages and the real-time deterministic context-free languages. Moreover, it is shown that the computational power of both types of machines...... is not changed by allowing the preprocessing sequential transducer to work irreversibly. Finally, we examine the closure properties of the family of languages accepted by such machines....

  13. Post-partum posterior reversible encephalopathy syndrome

    OpenAIRE

    B. V. Triveni; Salman Mohammed Sheikh; Deepak Shedde

    2014-01-01

    Posterior Reversible Encephalopathy Syndrome (PRES) is a clinicopathological syndrome associated with various clinical conditions presenting with headache, encephalopathy, seizure and cortical visual disturbances. Radiological findings in PRES are thought to be due to vasogenic edema predominantly in posterior cerebral hemispheres and are reversible with appropriate management. We present a case of post partum PRES,A 29 year old primigravida of 33 weeks 3 days period of gestation who prese...

  14. Elastic least-squares reverse time migration

    KAUST Repository

    Feng, Zongcai

    2016-09-06

    Elastic least-squares reverse time migration (LSRTM) is used to invert synthetic particle-velocity data and crosswell pressure field data. The migration images consist of both the P- and Svelocity perturbation images. Numerical tests on synthetic and field data illustrate the advantages of elastic LSRTM over elastic reverse time migration (RTM). In addition, elastic LSRTM images are better focused and have better reflector continuity than do the acoustic LSRTM images.

  15. Quality control of Photosystem II: reversible and irreversible protein aggregation decides the fate of Photosystem II under excessive illumination

    Directory of Open Access Journals (Sweden)

    Yasusi eYamamoto

    2013-10-01

    Full Text Available In response to excessive light, the thylakoid membranes of higher plant chloroplasts show dynamic changes including the degradation and reassembly of proteins, a change in the distribution of proteins, and large-scale structural changes such as unstacking of the grana. Here, we examined the aggregation of light-harvesting chlorophyll-protein complexes and Photosystem II core subunits of spinach thylakoid membranes under light stress with 77K chlorophyll fluorescence; aggregation of these proteins was found to proceed with increasing light intensity. Measurement of changes in the fluidity of thylakoid membranes with fluorescence polarization of diphenylhexatriene showed that membrane fluidity increased at a light intensity of 500–1,000 µmol photons m-2 s-1, and decreased at very high light intensity (1,500 µmol photons m-2 s-1. The aggregation of light-harvesting complexes at moderately high light intensity is known to be reversible, while that of Photosystem II core subunits at extremely high light intensity is irreversible. It is likely that the reversibility of protein aggregation is closely related to membrane fluidity: increases in fluidity should stimulate reversible protein aggregation, whereas irreversible protein aggregation might decrease membrane fluidity. When spinach leaves were pre-illuminated with moderately high light intensity, the qE component of non-photochemical quenching and the optimum quantum yield of Photosystem II increased, indicating that Photosystem II/ light-harvesting complexes rearranged in the thylakoid membranes to optimize Photosystem II activity. Transmission electron microscopy revealed that the thylakoids underwent partial unstacking under these light stress conditions. Thus, protein aggregation is involved in thylakoid dynamics and regulates photochemical reactions, thereby deciding the fate of Photosystem II.

  16. A bi-stable SOC model for Earth's magnetic field reversals

    International Nuclear Information System (INIS)

    Papa, A.R.R.; Espírito Santo, M.A. do; Barbosa, C.S.; Oliva, D.

    2013-01-01

    We introduce a simple model for Earth's magnetic field reversals. The model consists in random nodes simulating vortices in the liquid core which through a simple updating algorithm converge to a self-organized critical state, with inter-reversal time probability distributions functions in the form of power-laws for long persistence times (as supposed to be in actual reversals). A detailed description of reversals should not be expected. However, we hope to reach a profounder knowledge on reversals through some of the basic characteristic that are well reproduced. The work opens several future research trends.

  17. Heuristic Synthesis of Reversible Logic – A Comparative Study

    Directory of Open Access Journals (Sweden)

    Chua Shin Cheng

    2014-01-01

    Full Text Available Reversible logic circuits have been historically motivated by theoretical research in low-power, and recently attracted interest as components of the quantum algorithm, optical computing and nanotechnology. However due to the intrinsic property of reversible logic, traditional irreversible logic design and synthesis methods cannot be carried out. Thus a new set of algorithms are developed correctly to synthesize reversible logic circuit. This paper presents a comprehensive literature review with comparative study on heuristic based reversible logic synthesis. It reviews a range of heuristic based reversible logic synthesis techniques reported by researchers (BDD-based, cycle-based, search-based, non-search-based, rule-based, transformation-based, and ESOP-based. All techniques are described in detail and summarized in a table based on their features, limitation, library used and their consideration metric. Benchmark comparison of gate count and quantum cost are analysed for each synthesis technique. Comparing the synthesis algorithm outputs over the years, it can be observed that different approach has been used for the synthesis of reversible circuit. However, the improvements are not significant. Quantum cost and gate count has improved over the years, but arguments and debates are still on certain issues such as the issue of garbage outputs that remain the same. This paper provides the information of all heuristic based synthesis of reversible logic method proposed over the years. All techniques are explained in detail and thus informative for new reversible logic researchers and bridging the knowledge gap in this area.

  18. Clinical outcomes for 14 consecutive patients with solid pseudopapillary neoplasms who underwent laparoscopic distal pancreatectomy.

    Science.gov (United States)

    Nakamura, Yoshiharu; Matsushita, Akira; Katsuno, Akira; Yamahatsu, Kazuya; Sumiyoshi, Hiroki; Mizuguchi, Yoshiaki; Uchida, Eiji

    2016-02-01

    The postoperative results of laparoscopic distal pancreatectomy for solid pseudopapillary neoplasm of the pancreas (SPN), including the effects of spleen-preserving resection, are still to be elucidated. Of the 139 patients who underwent laparoscopic pancreatectomy for non-cancerous tumors, 14 consecutive patients (average age, 29.6 years; 1 man, 13 women) with solitary SPN who underwent laparoscopic distal pancreatectomy between March 2004 and June 2015 were enrolled. The tumors had a mean diameter of 4.8 cm. Laparoscopic spleen-preserving distal pancreatectomy was performed in eight patients (spleen-preserving group), including two cases involving pancreatic tail preservation, and laparoscopic spleno-distal pancreatectomy was performed in six patients (standard resection group). The median operating time was 317 min, and the median blood loss was 50 mL. Postoperatively, grade B pancreatic fistulas appeared in two patients (14.3%) but resolved with conservative treatment. No patients had postoperative complications, other than pancreatic fistulas, or required reoperation. The median postoperative hospital stay was 11 days, and the postoperative mortality was zero.None of the patients had positive surgical margins or lymph nodes with metastasis. The median follow-up period did not significantly differ between the two groups (20 vs 39 months, P = 0.1368). All of the patients are alive and free from recurrent tumors without major late-phase complications. Laparoscopic distal pancreatectomy might be a suitable treatment for patients with SPN. A spleen-preserving operation is preferable for younger patients with SPN, and this study demonstrated the non-inferiority of the procedure compared to spleno-distal pancreatectomy. © 2015 Japan Society for Endoscopic Surgery, Asia Endosurgery Task Force and John Wiley & Sons Australia, Ltd.

  19. Reversibility and the structure of the local state space

    International Nuclear Information System (INIS)

    Al-Safi, Sabri W; Richens, Jonathan

    2015-01-01

    The richness of quantum theory’s reversible dynamics is one of its unique operational characteristics, with recent results suggesting deep links between the theory’s reversible dynamics, its local state space and the degree of non-locality it permits. We explore the delicate interplay between these features, demonstrating that reversibility places strong constraints on both the local and global state space. Firstly, we show that all reversible dynamics are trivial (composed of local transformations and permutations of subsytems) in maximally non-local theories whose local state spaces satisfy a dichotomy criterion; this applies to a range of operational models that have previously been studied, such as d-dimensional ‘hyperballs’ and almost all regular polytope systems. By separately deriving a similar result for odd-sided polygons, we show that classical systems are the only regular polytope state spaces whose maximally non-local composites allow for non-trivial reversible dynamics. Secondly, we show that non-trivial reversible dynamics do exist in maximally non-local theories whose state spaces are reducible into two or more smaller spaces. We conjecture that this is a necessary condition for the existence of such dynamics, but that reversible entanglement generation remains impossible even in this scenario. (paper)

  20. Slowly switching between environments facilitates reverse evolution in small populations

    Science.gov (United States)

    Tan, Longzhi; Gore, Jeff

    2011-03-01

    The rate at which a physical process occurs usually changes the behavior of a system. In thermodynamics, the reversibility of a process generally increases when it occurs at an infinitely slow rate. In biological evolution, adaptations to a new environment may be reversed by evolution in the ancestral environment. Such fluctuating environments are ubiquitous in nature, although how the rate of switching affects reverse evolution is unknown. Here we use a computational approach to quantify evolutionary reversibility as a function of the rate of switching between two environments. For small population sizes, which travel on landscapes as random walkers, we find that both genotypic and phenotypic reverse evolution increase at slow switching rates. However, slow switching of environments decreases evolutionary reversibility for a greedy walker, corresponding to large populations (extensive clonal interference). We conclude that the impact of the switching rate for biological evolution is more complicated than other common physical processes, and that a quantitative approach may yield significant insight into reverse evolution.

  1. Long-acting reversible contraceptives: intrauterine devices and the contraceptive implant.

    Science.gov (United States)

    Espey, Eve; Ogburn, Tony

    2011-03-01

    The provision of effective contraception is fundamental to the practice of women's health care. The most effective methods of reversible contraception are the so-called long-acting reversible contraceptives, intrauterine devices and implants. These methods have multiple advantages over other reversible methods. Most importantly, once in place, they do not require maintenance and their duration of action is long, ranging from 3 to 10 years. Despite the advantages of long-acting reversible contraceptive methods, they are infrequently used in the United States. Short-acting methods, specifically oral contraceptives and condoms, are by far the most commonly used reversible methods. A shift from the use of short-acting methods to long-acting reversible contraceptive methods could help reduce the high rate of unintended pregnancy in the United States. In this review of long-acting reversible contraceptive methods, we discuss the intrauterine devices and the contraceptive implant available in the United States, and we describe candidates for each method, noncontraceptive benefits, and management of complications.

  2. Paleomagnetic Study of a Reversal of the Earth's Magnetic Field.

    Science.gov (United States)

    Dunn, J R; Fuller, M; Ito, H; Schmidt, V A

    1971-05-21

    A detailed record of a field reversal has been obtained from the natural remanent magnetization of the Tatoosh intrusion in Mount Rainier National Park, Washington. The reversal took place at 14.7 +/- 1 million years and is interpreted to be from reverse to normal. A decrease in the intensity of the field of about an order of magnitude occurs immediately before the reversal, while its orientation remains substantially unchanged. The onset of the reversal is marked by abrupt swinging of the virtual geomagnetic pole along an arc of a great circle. During the reversal the pole traces a path across the Pacific. In the last stage of the process recorded in the sections, the succession of virtual geomagnetic poles is very similar to those generated by secular variation in the recent past. Although the cooling rate of the intrusion is not sufficiently well known to permit a useful calculation of the duration of the reversal process, an estimate based on the length of the supposed secular variation cycles gives 1 to 4 x 103 years for the reversal of field direction and approximately 1 x 104 years for the time scale of the intensity changes.

  3. Time in Science: Reversibility vs. Irreversibility

    Science.gov (United States)

    Pomeau, Yves

    To discuss properly the question of irreversibility one needs to make a careful distinction between reversibility of the equations of motion and the choice of the initial conditions. This is also relevant for the rather confuse philosophy of the wave packet reduction in quantum mechanics. The explanation of this reduction requires also to make precise assumptions on what initial data are accessible in our world. Finally I discuss how a given (and long) time record can be shown in an objective way to record an irreversible or reversible process. Or: can a direction of time be derived from its analysis? This leads quite naturally to examine if there is a possible spontaneous breaking of the time reversal symmetry in many body systems, a symmetry breaking that would be put in evidence objectively by looking at certain specific time correlations.

  4. Reverse hybrid total hip arthroplasty

    DEFF Research Database (Denmark)

    Wangen, Helge; Havelin, Leif I.; Fenstad, Anne M

    2017-01-01

    Background and purpose - The use of a cemented cup together with an uncemented stem in total hip arthroplasty (THA) has become popular in Norway and Sweden during the last decade. The results of this prosthetic concept, reverse hybrid THA, have been sparsely described. The Nordic Arthroplasty....... Patients and methods - From the NARA, we extracted data on reverse hybrid THAs from January 1, 2000 until December 31, 2013. 38,415 such hips were studied and compared with cemented THAs. The Kaplan-Meier method and Cox regression analyses were used to estimate the prosthesis survival and the relative risk...

  5. Reverse Zymography: Overview and Pitfalls.

    Science.gov (United States)

    Sharma, Kanika; Bhattacharyya, Debasish

    2017-01-01

    Reverse zymography is a technique by which protease inhibitor(s) in a sample could be electrophoretically separated in a substrate-impregnated acrylamide gel and their relative abundance could be semi-quantified. The gel after electrophoresis is incubated with a protease when the impregnated substrate and all other proteins of the sample are degraded into small peptides except the inhibitor(s) that show clear bands against a white background. Since reverse zymography cannot distinguish between a protease inhibitor and a protein that is resistant against proteolysis, the results should be confirmed from inhibition of protease activity by solution state assay.

  6. Targeted Endovascular Temporary Vessel Occlusion with a Reverse Thermosensitive Polymer for Near-Bloodless Partial Nephrectomy: Comparison to Standard Surgical Clamping Techniques

    Energy Technology Data Exchange (ETDEWEB)

    Flacke, Sebastian, E-mail: Sebastian.Flacke@lahey.org [Lahey Clinic, Tuft University Medical School, Department of Radiology (United States); Harty, Niall J.; Laskey, Daniel H.; Moinzadeh, Alireza [Lahey Clinic, Tuft University Medical School, Department of Urology (United States); Benn, James A. [Pluromed Inc (United States); Villani, Rosanna [DaVinci Biomedical Research Products (United States); Kalra, Aarti [Lahey Clinic, Tuft University Medical School, Department of Pathology (United States); Libertino, John A.; Madras, Peter N. [Lahey Clinic, Tuft University Medical School, Department of Urology (United States)

    2012-10-15

    Purpose: To determine whether reversible blood flow interruption to a randomly chosen target region of the kidney may be achieved with the injection of a reverse thermoplastic polymer through an angiographic catheter, thereby facilitating partial nephrectomy without compromising blood flow to the remaining kidney or adding risks beyond those encountered by the use of hilar clamping. Methods: Fifteen pigs underwent partial nephrectomy after blood flow interruption by vascular cross-clamping or injection of polymer (Lumagel Trade-Mark-Sign ) into a segmental artery. Five animals were euthanized after surgery (three open and two laparoscopic resection, cross-clamping n = 2), and 10 (open resection, cross-clamping n = 4) were euthanized after 6 weeks' survival. Blood specimens were obtained periodically, and angiogram and necropsy were performed at 6 weeks. Results: Selective renal ischemia was achieved in all cases. Surgical resection time averaged 9 and 24.5 min in the open and laparoscopic groups, respectively. Estimated blood loss was negligible with the exception of one case where an accessory renal artery was originally overlooked. Reversal of the polymer to a liquid state was consistent angiographically and visually in all cases. Time to complete flow return averaged 7.4 and 2 min for polymer and clamping, respectively. Angiography at 6 weeks revealed no evidence of vascular injury. Laboratory data and necropsies revealed no differences between animals undergoing vascular clamping or polymer injection. Conclusion: Lumagel was as effective as vascular clamping in producing a near bloodless operative field for partial nephrectomy while maintaining flow to the uninvolved portion of the affected kidney.

  7. Revision of failed shoulder hemiarthroplasty to reverse total arthroplasty: analysis of 157 revision implants.

    Science.gov (United States)

    Merolla, Giovanni; Wagner, Eric; Sperling, John W; Paladini, Paolo; Fabbri, Elisabetta; Porcellini, Giuseppe

    2018-01-01

    There remains a paucity of studies examining the conversion of failed hemiarthroplasty (HA) to reverse total shoulder arthroplasty (RTSA). Therefore, the purpose of this study was to examine a large series of revision HA to RTSA. A population of 157 patients who underwent conversion of a failed HA to a revision RTSA from 2006 through 2014 were included. The mean follow-up was 49 months (range, 24-121 months). The indications for revision surgery included instability with rotator cuff insufficiency (n = 127) and glenoid wear (n = 30); instability and glenoid wear were associated in 38 cases. Eight patients with infection underwent 2-stage reimplantation. Patients experienced significant improvements in their preoperative to postoperative pain and shoulder range of motion (P surgeries, secondary to glenoid component loosening (n = 3), instability (n = 3), humeral component disassembly (n = 2), humeral stem loosening (n = 1), and infection (n = 2). Implant survivorship was 95.5% at 2 years and 93.3% at 5 years. There were 4 reoperations including axillary nerve neurolysis (n = 2), heterotopic ossification removal (n = 1), and hardware removal for rupture of the metal cerclage for an acromial fracture (n = 1). At final follow-up, there were 5 "at-risk" glenoid components. Patients experience satisfactory pain relief and recovery of reasonable shoulder function after revision RTSA from a failed HA. There was a relatively low revision rate, with glenoid loosening and instability being the most common causes. Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

  8. Revenue in reverse? An examination of reverse supply chain enabled revenue streams

    DEFF Research Database (Denmark)

    Larsen, Samuel; Jacobsen, Peter

    2016-01-01

    When original equipment manufacturers (OEMs) examine whether to implement a reverse supply chain (RSC) for their products, oftentimes the motive is cost savings or regulatory compliance. However, a frequently overlooked but equally important benefit is the possibility for creating new revenue...

  9. Chemical-looping combustion in a reverse-flow fixed bed reactor

    International Nuclear Information System (INIS)

    Han, Lu; Bollas, George M.

    2016-01-01

    A reverse-flow fixed bed reactor concept for CLC (chemical-looping combustion) is explored. The limitations of conventional fixed bed reactors, as applied to CLC, are overcome by reversing the gas flow direction periodically to enhance the mixing characteristics of the bed, thus improving oxygen carrier utilization and energy efficiency with respect to power generation. The reverse-flow reactor is simulated by a dusty-gas model and compared with an equivalent fixed bed reactor without flow reversal. Dynamic optimization is used to calculate conditions at which each reactor operates at maximum energy efficiency. Several cases studies illustrate the benefits of reverse-flow operation for the CLC with CuO and NiO oxygen carriers and methane and syngas fuels. The results show that periodic reversal of the flow during reduction improves the contact between the fuel and unconverted oxygen carrier, enabling the system to suppress unwanted catalytic reactions and axial temperature and conversion gradients. The operational scheme presented reduces the fluctuations of temperature during oxidation and increases the high-temperature heat produced by the process. CLC in a reverse-flow reactor has the potential to achieve higher energy efficiency than conventional fixed bed CLC reactors, when integrated with a downstream gas turbine of a combined cycle power plant. - Highlights: • Reverse-flow fixed bed CLC reactors for combined cycle power systems. • Dynamic optimization tunes operation of batch and transient CLC systems. • The reverse-flow CLC system provides stable turbine-ready gas stream. • Reverse-flow CLC fixed bed reactor has superior CO 2 capture and thermal efficiency.

  10. Photophysical properties of pyronin dyes in reverse micelles of AOT

    Energy Technology Data Exchange (ETDEWEB)

    Bayraktutan, Tuğba; Meral, Kadem; Onganer, Yavuz, E-mail: yonganer@atauni.edu.tr

    2014-01-15

    The photophysical properties of pyronin B (PyB) and pyronin Y (PyY) in reverse micelles formed with water/sodium bis (2-ethyl-1-hexyl) sulfosuccinate (AOT)/n-heptane were investigated by UV–vis absorption, steady-state and time-resolved fluorescence spectroscopy techniques. This study was carried out a wide range of reverse micelle sizes, with hydrodynamic radii ranging from 1.85 to 9.38 nm. Significant photophysical parameters as band shifts, fluorescence quantum yields and fluorescence lifetimes were determined to understand how photophysical and spectroscopic features of the dye compounds were affected by the variation of reverse micelle sizes. In this regard, control of reverse micelle size by changing W{sub 0}, the molar ratio of water to surfactant, allowed tuning the photophysical properties of the dyes in organic solvent via reverse micelle. Non-fluorescent H-aggregates of pyronin dyes were observed for the smaller reverse micelles whereas an increase in the reverse micelle size induced an increment in the amount of dye monomers instead of dye aggregates. Thus, the fluorescence intensities of the dyes were improved by increasing W{sub 0} due to the predomination of the fluorescent dye monomers. As a result, the fluorescence quantum yields also increased. The fluorescence lifetimes of the dyes in the reverse micelles were determined by the time-resolved fluorescence decay studies. Evaluation of the fluorescence lifetimes calculated for pyronin dyes in the reverse micelles showed that the size of reverse micelle affected the fluorescence lifetimes of pyronin dyes. -- Highlights: • The photophysical properties of pyronin dyes were examined by spectroscopic techniques. • Optical properties of the dyes were tuned by changing of W{sub 0} values. • The fluorescence lifetime and quantum yield values of the dyes in reverse micelles were discussed.

  11. SLE local martingales, reversibility and duality

    Energy Technology Data Exchange (ETDEWEB)

    Kytoelae, Kalle; Kemppainen, Antti [Department of Mathematics and Statistics, PO Box 68, FIN-00014 University of Helsinki (Finland)

    2006-11-17

    We study Schramm-Loewner evolutions (SLEs) reversibility and duality using the Virasoro structure of the space of local martingales. For both problems we formulate a setup where the questions boil down to comparing two processes at a stopping time. We state algebraic results showing that local martingales for the processes have enough in common. When one has in addition integrability, the method gives reversibility and duality for any polynomial expected value. (letter to the editor)

  12. SLE local martingales, reversibility and duality

    International Nuclear Information System (INIS)

    Kytoelae, Kalle; Kemppainen, Antti

    2006-01-01

    We study Schramm-Loewner evolutions (SLEs) reversibility and duality using the Virasoro structure of the space of local martingales. For both problems we formulate a setup where the questions boil down to comparing two processes at a stopping time. We state algebraic results showing that local martingales for the processes have enough in common. When one has in addition integrability, the method gives reversibility and duality for any polynomial expected value. (letter to the editor)

  13. Time reversibility of quantum diffusion in small-world networks

    Science.gov (United States)

    Han, Sung-Guk; Kim, Beom Jun

    2012-02-01

    We study the time-reversal dynamics of a tight-binding electron in the Watts-Strogatz (WS) small-world networks. The localized initial wave packet at time t = 0 diffuses as time proceeds until the time-reversal operation, together with the momentum perturbation of the strength η, is made at the reversal time T. The time irreversibility is measured by I = |Π( t = 2 T) - Π( t = 0)|, where Π is the participation ratio gauging the extendedness of the wavefunction and for convenience, t is measured forward even after the time reversal. When η = 0, the time evolution after T makes the wavefunction at t = 2 T identical to the one at t = 0, and we find I = 0, implying a null irreversibility or a complete reversibility. On the other hand, as η is increased from zero, the reversibility becomes weaker, and we observe enhancement of the irreversibility. We find that I linearly increases with increasing η in the weakly-perturbed region, and that the irreversibility is much stronger in the WS network than in the local regular network.

  14. Reverse time migration by Krylov subspace reduced order modeling

    Science.gov (United States)

    Basir, Hadi Mahdavi; Javaherian, Abdolrahim; Shomali, Zaher Hossein; Firouz-Abadi, Roohollah Dehghani; Gholamy, Shaban Ali

    2018-04-01

    Imaging is a key step in seismic data processing. To date, a myriad of advanced pre-stack depth migration approaches have been developed; however, reverse time migration (RTM) is still considered as the high-end imaging algorithm. The main limitations associated with the performance cost of reverse time migration are the intensive computation of the forward and backward simulations, time consumption, and memory allocation related to imaging condition. Based on the reduced order modeling, we proposed an algorithm, which can be adapted to all the aforementioned factors. Our proposed method benefit from Krylov subspaces method to compute certain mode shapes of the velocity model computed by as an orthogonal base of reduced order modeling. Reverse time migration by reduced order modeling is helpful concerning the highly parallel computation and strongly reduces the memory requirement of reverse time migration. The synthetic model results showed that suggested method can decrease the computational costs of reverse time migration by several orders of magnitudes, compared with reverse time migration by finite element method.

  15. Ageing, fragility and the reversibility window in bulk alloy glasses

    International Nuclear Information System (INIS)

    Chakravarty, S; Georgiev, D G; Boolchand, P; Micoulaut, M

    2005-01-01

    Non-reversing relaxation enthalpies (ΔH nr ) at glass transitions T g (x) in the P x Ge x Se 1-2x ternary display wide, sharp and deep global minima (∼0) in the 0.09 g s become thermally reversing. In this reversibility window, glasses are found not to age, in contrast to ageing observed for fragile glass compositions outside the window. Thermal reversibility and lack of ageing seem to be paradigms of self-organization which molecular glasses share with protein structures which repetitively and reversibly change conformation near T g and the folding temperature respectively. (letter to the editor)

  16. A simple and efficient universal reversible Turing machine

    DEFF Research Database (Denmark)

    Axelsen, Holger Bock; Glück, Robert

    2011-01-01

    We construct a universal reversible Turing machine (URTM) from first principles. We take a strict approach to the semantics of reversible Turing machines (RTMs), under which they can compute exactly all injective, computable functions, but not non-injective ones. The natural notion of universalit...... factor slowdown, with no other complexity-wise cost wrt time and space. The URTM is also able to function as an inverse interpreter for RTMs at no asymptotic cost, simply by reversing the string representing the interpreted machine....

  17. Fuel bundle impact velocities due to reverse flow

    International Nuclear Information System (INIS)

    Wahba, N.N.; Locke, K.E.

    1996-01-01

    If a break should occur in the inlet feeder or inlet header of a CANDU reactor, the rapid depressurization will cause the channel flow(s) to reverse. Depending on the gap between the upstream bundle and shield plug, the string of bundles will accelerate in the reverse direction and impact with the upstream shield plug. The reverse flow impact velocities have been calculated for various operating states for the Bruce NGS A reactors. The sensitivity to several analysis assumptions has been determined. (author)

  18. Factors affecting timing of closure and non-reversal of temporary ileostomies

    NARCIS (Netherlands)

    Sier, M. F.; van Gelder, L.; Ubbink, D. T.; Bemelman, W. A.; Oostenbroek, R. J.

    2015-01-01

    Although stoma closure is considered a simple surgical intervention, the interval between construction and reversal is often prolonged, and some ileostomies may never be reversed. We evaluated possible predictors for non-reversal and prolonged interval between construction and reversal. In a cohort

  19. Local particle flux reversal under strongly sheared flow

    International Nuclear Information System (INIS)

    Terry, P.W.; Newman, D.E.; Ware, A.S.

    2003-01-01

    The advection of electron density by turbulent ExB flow with linearly varying mean yields a particle flux that can reverse sign at certain locations along the direction of magnetic shear. The effect, calculated for strong flow shear, resides in the density-potential cross phase. It is produced by the interplay between the inhomogeneities of magnetic shear and flow shear, but subject to a variety of conditions and constraints. The regions of reversed flux tend to wash out if the turbulence consists of closely spaced modes of different helicities, but survive if modes of a single helicity are relatively isolated. The reversed flux becomes negligible if the electron density response is governed by electron scales while the eigenmode is governed by ion scales. The relationship of these results to experimentally observe flux reversals is discussed

  20. Loss of object recognition memory produced by extended access to methamphetamine self-administration is reversed by positive allosteric modulation of metabotropic glutamate receptor 5.

    Science.gov (United States)

    Reichel, Carmela M; Schwendt, Marek; McGinty, Jacqueline F; Olive, M Foster; See, Ronald E

    2011-03-01

    Chronic methamphetamine (meth) abuse can lead to persisting cognitive deficits. Here, we utilized a long-access meth self-administration (SA) protocol to assess recognition memory and metabotropic glutamate receptor (mGluR) expression, and the possible reversal of cognitive impairments with the mGluR5 allosteric modulator, 3-cyano-N-(1,3-diphenyl-1H-pyrazol-5-yl) benzamide (CDPPB). Male, Long-Evans rats self-administered i.v. meth (0.02 mg/infusion) on an FR1 schedule of reinforcement or received yoked-saline infusions. After seven daily 1-h sessions, rats were switched to 6-h daily sessions for 14 days, and then underwent drug abstinence. Rats were tested for object recognition memory at 1 week after meth SA at 90 min and 24 h retention intervals. In a separate experiment, rats underwent the same protocol, but received either vehicle or CDPPB (30 mg/kg) after familiarization. Rats were killed on day 8 or 14 post-SA and brain tissue was obtained. Meth intake escalated over the extended access period. Additionally, meth-experienced rats showed deficits in both short- and long-term recognition memory, demonstrated by a lack of novel object exploration. The deficit at 90 min was reversed by CDPPB treatment. On day 8, meth intake during SA negatively correlated with mGluR expression in the perirhinal and prefrontal cortex, and mGluR5 receptor expression was decreased 14 days after discontinuation of meth. This effect was specific to mGluR5 levels in the perirhinal cortex, as no differences were identified in the hippocampus or in mGluR2/3 receptors. These results from a clinically-relevant animal model of addiction suggest that mGluR5 receptor modulation may be a potential treatment of cognitive dysfunction in meth addiction.