WorldWideScience

Sample records for characterize nitrogen ligation

  1. A multiplex ligation detection assay for the characterization of Salmonella enterica strains

    DEFF Research Database (Denmark)

    Aarts, Henk J.M.; Vos, Pieter; Larsson, Jonas T.

    2011-01-01

    A proof of principle of a multi-target assay for genotyping Salmonella has been developed targeting 62 genomic marker sequences of Salmonella related to pathogenicity. The assay is based on multiplex ligation detection reaction (LDR) followed by customized ArrayTube® microarray detection. The fea......A proof of principle of a multi-target assay for genotyping Salmonella has been developed targeting 62 genomic marker sequences of Salmonella related to pathogenicity. The assay is based on multiplex ligation detection reaction (LDR) followed by customized ArrayTube® microarray detection...... of four serovars each serovar was characterized by a unique virulence associated gene repertoire. The LDR microarray platform proved to be a convenient, rapid and easy to use tool with potential in tracing a Salmonella contamination in the food chain, for outbreak studies, and to provide data for risk...

  2. Isolation and characterization of portal branch ligation-stimulated Hmga2-positive bipotent hepatic progenitor cells

    Energy Technology Data Exchange (ETDEWEB)

    Sakai, Hiroshi [Department of Surgery, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, Nagano 390-8621 (Japan); Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 B51, Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503 (Japan); Tagawa, Yoh-ichi, E-mail: ytagawa@bio.titech.ac.jp [Frontier Research Center, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503 (Japan); Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 B51, Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503 (Japan); PRESTO, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012 (Japan); Tamai, Miho [Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, 4259 B51, Nagatsuta-cho, Midori-ku, Yokohama, Kanagawa 226-8503 (Japan); Motoyama, Hiroaki [Department of Surgery, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, Nagano 390-8621 (Japan); Ogawa, Shinichiro [Department of Surgery, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, Nagano 390-8621 (Japan); McEwen Center for Regenerative Medicine, University Health Network, 190 Elizabeth Street, Toronto, Ont., Canada M5G 2C4 (Canada); Soeda, Junpei; Nakata, Takenari; Miyagawa, Shinichi [Department of Surgery, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, Nagano 390-8621 (Japan)

    2010-12-17

    Research highlights: {yields} Hepatic progenitor cells were isolated from the portal branch-ligated liver of mice. {yields} Portal branch ligation-stimulated hepatic progenitor cells (PBLHCs) express Hmga2. {yields} PBLHCs have bidirectional differentiation capability in vitro. -- Abstract: Hepatic stem/progenitor cells are one of several cell sources that show promise for restoration of liver mass and function. Although hepatic progenitor cells (HPCs), including oval cells, are induced by administration of certain hepatotoxins in experimental animals, such a strategy would be inappropriate in a clinical setting. Here, we investigated the possibility of isolating HPCs in a portal branch-ligated liver model without administration of any chemical agents. A non-parenchymal cell fraction was prepared from the portal branch-ligated or non-ligated lobe, and seeded onto plates coated with laminin. Most of the cells died, but a small number were able to proliferate. These proliferating cells were cloned as portal branch ligation-stimulated hepatic cells (PBLHCs) by the limiting dilution method. The PBLHCs expressed cytokeratin19, albumin, and Hmga2. The PBLHCs exhibited metabolic functions such as detoxification of ammonium ions and synthesis of urea on Matrigel-coated plates in the presence of oncostatin M. In Matrigel mixed with type I collagen, the PBLHCs became rearranged into cystic and tubular structures. Immunohistochemical staining demonstrated the presence of Hmga2-positive cells around the interlobular bile ducts in the portal branch-ligated liver lobes. In conclusion, successful isolation of bipotent hepatic progenitor cell clones, PBLHCs, from the portal branch-ligated liver lobes of mice provides the possibility of future clinical application of portal vein ligation to induce hepatic progenitor cells.

  3. Characterization of partial ligation-induced carotid atherosclerosis model using dual-modality molecular imaging in ApoE knock-out mice.

    Directory of Open Access Journals (Sweden)

    Ik Jae Shin

    Full Text Available BACKGROUND: Recently, partial ligation of the common carotid artery (CCA was reported to induce carotid atheromata rapidly in apolipoprotein-E knockout (ApoE(-/- mice. We investigated this new atherosclerosis model by using combined matrix-metalloproteinase (MMP near-infrared fluorescent (NIRF imaging and macrophage-tracking luciferase imaging. METHODOLOGY AND PRINCIPAL FINDINGS: Partial ligation of the left CCA was performed in 10-week-old ApoE(-/- mice on a high fat diet (n=33; the internal and external carotid arteries and occipital artery were ligated, while the superior thyroid artery was left intact. Two thirds of the animals were treated with either LiCl or atorvastatin. At 1-week, Raw264.7 macrophages modified to express the enhanced firefly-luciferase reporter gene (10(7 Raw-luc cells were injected intravenously. At 2-week, NIRF molecular imaging visualized strong MMP-2/9 activity in the ligated area of the left CCA as well as in the aortic arch. Left-to-right ratios of the NIRF signal intensities in the CCA had a decreasing gradient from the highest value in the upper-most ligated area to the lowest value in the lower-most region adjacent to the aortic arch. Luciferase imaging showed that most Raw-luc macrophages were recruited to the ligated area of the CCA rather than to the aortic arch, despite similarly strong MMP-2/9-related NIRF signal intensities in both areas. In addition, LiCl or atorvastatin could reduce MMP-2/9 activity in the aortic arch but not in the ligated area of the CCA. CONCLUSIONS/SIGNIFICANCE: This is the first molecular imaging study to characterize the partial ligation-induced carotid atherosclerosis model. Molecularly divergent types of atherosclerosis were identified: conventional lipogenic atherosclerosis in the aorta vs. flow-related mechanical atherosclerosis in the partially ligated left system.

  4. Kinetic characterization of on-chip DNA ligation on dendron-coated surfaces with nanoscaled lateral spacings

    Science.gov (United States)

    Kim, Eung-Sam; Lee, Namgyu; Park, Joon Won; Choi, Kwan Yong

    2013-10-01

    We analyzed the enzymatic profiles of on-chip DNA ligation as we controlled the lateral spacing of surface-immobilized DNA substrates using dendron molecules with different sizes at the nanoscale. Enzymatic on-chip DNA ligation was performed on the dendron-coated surface within 20 min with no need for post-ligation gel electrophoresis. The enzymatic DNA repair was assessed by the fluorescence intensity at the repaired DNA duplex after thermally dissociating the unligated Cy3-labeled DNA from the DNA duplex, in which the Cy3-labeled DNA was hybridized prior to the on-chip DNA ligation. The rate of the nick-sealing reaction on the 27-acid dendron surface was 3-fold higher than that on the 9-acid dendron surface, suggesting that the wider lateral spacing determined by the larger dendron molecule could facilitate the access of DNA ligase to the nick site. The performance of on-chip DNA ligation was dropped to 10% and 3% when the nick was replaced by one- and two-nucleotide-long gaps, respectively. The 5‧ terminal phosphorylation of DNA strands by polynucleotide kinase and the on-chip DNA cleavage by endonucleases were also quantitatively monitored throughout the on-chip DNA ligation on the dendron-coated surface. A better understanding of the enzymatic kinetics of on-chip DNA ligation will contribute to a more reliable performance of various on-chip DNA ligation-based assays.

  5. Synthesis and Spectroscopic Studies of Axially Ligated Zn(II5,10,15,20-meso-tetra(p-chlorophenylporphyrin with Oxygen and Nitrogen Donors

    Directory of Open Access Journals (Sweden)

    Gauri D. Bajju

    2013-01-01

    Full Text Available Reaction of 5,10,15,20-meso-tetra(p-chlorophenylporphyrin[H2(p-Clpp] with zinc(IIacetate(Zn(OAc2 and phenols results in the formation of corresponding axially ligated zinc(II-meso-tetra(p-chlorophenylporphyrin (X-Zn-t(p-ClPP (X = phenolates and pyridinates. The four-coordinated zinc porphyrin accepts one axial ligand in 1 : 1 molar ratio to form five-coordinated complex, which is purified by column chromatography and characterized by IR spectra, 1H NMR, electronic absorption spectra, elemental analysis, mass spectroscopy, and TGA/DTA studies. IR spectra confirms the appearance of Zn– at 500–400 cm−1, Zn– at 650–570 cm−1 and Zn–O at 650–350 cm−1. 1H NMR spectra show that the protons of the Phenolic ring axially attached to the central metal ion are merged with the protons of the tetraphenyl rings of the porphyrin moiety. Absorption spectra reveal that complexes are accompanied by blue shift (hypsochromic shift for phenolates and red shift (bathchromic shift for pyridinates in comparison with the basic Zporphyrin emission bands. Mass Spectra determine the m/z ratio. The percentage of each element is confirmed by elemental analysis. According to the thermal studies, the complexes have a higher thermal stability and the decomposition temperature of these complexes depends on the axial ligation. The invitro antifungal activity of the complexes synthesized above had been done by disc diffusion method against the pathogen “Fusarium spp.,” which shows that with the increase in the concentration of the complexes, the colony diameter decreases and hence percent inhibition increases.

  6. Kinetics and equilibria for the axial ligation of bromomethyl (aqua)cobaloxime with pyridines - Isolation characterization and DNA binding

    Indian Academy of Sciences (India)

    Kotha Laxma Reddy; K Ashwini Kumar; N Ravi Kumar Reddy; Penumaka Nagababu; A Panasa Reddy; S Satyanarayana

    2009-11-01

    The kinetics and equilibria for the axial ligation of pyridine and substituted pyridines to bromomethyl(aqua)cobaloxime have been measured spectrophotometrically in aqueous solutions of ionic strength 1.0 M (KC1) at 25°C as a function of H. The binding constants and rate of formation increase in the order 4-NH2Py 4-EtPy > 4-MePy > Py > 2-NH2Py > 2-EtPy. The data have been interpreted based on the basicity of the ligand, -back bonding from Co(III) → L and hard and soft interactions. The rate of substitution of H2O varies with the pKa of the incoming ligand, thus establishing the existence of nucleophilic participation of the ligand in the transition state. We have investigated the DNA binding of bromomethyl(aqua)cobaloxime with DNA. Bromomethyl(ligand)cobaloximes were isolated and characterized by elemental analysis, IR and NMR (1H, 13C) spectra.

  7. Chemoselective ligation

    Energy Technology Data Exchange (ETDEWEB)

    Saxon, Eliana; Bertozzi, Carolyn

    2006-10-17

    The present invention features a chemoselective ligation reaction that can be carried out under physiological conditions. In general, the invention involves condensation of a specifically engineered phosphine, which can provide for formation of an amide bond between the two reactive partners resulting in a final product comprising a phosphine moiety, or which can be engineered to comprise a cleavable linker so that a substituent of the phosphine is transferred to the azide, releasing an oxidized phosphine byproduct and producing a native amide bond in the final product. The selectivity of the reaction and its compatibility with aqueous environments provides for its application in vivo (e.g., on the cell surface or intracellularly) and in vitro (e.g., synthesis of peptides and other polymers, production of modified (e.g., labeled) amino acids).

  8. Chemoselective ligation

    Energy Technology Data Exchange (ETDEWEB)

    Saxon, Eliana (Albany, CA); Bertozzi, Carolyn (Berkeley, CA)

    2003-05-27

    The present invention features a chemoselective ligation reaction that can be carried out under physiological conditions. In general, the invention involves condensation of a specifically engineered phosphine, which can provide for formation of an amide bond between the two reactive partners resulting in a final product comprising a phosphine moiety, or which can be engineered to comprise a cleavable linker so that a substituent of the phosphine is transferred to the azide, releasing an oxidized phosphine byproduct and producing a native amide bond in the final product. The selectivity of the reaction and its compatibility with aqueous environments provides for its application in vivo (e.g., on the cell surface or intracellularly) and in vitro (e.g., synthesis of peptides and other polymers, production of modified (e.g., labeled) amino acids).

  9. Chemoselective ligation

    Energy Technology Data Exchange (ETDEWEB)

    Saxon, Eliana (Albany, CA); Bertozzi, Carolyn R. (Berkeley, CA)

    2010-02-23

    The present invention features a chemoselective ligation reaction that can be carried out under physiological conditions. In general, the invention involves condensation of a specifically engineered phosphine, which can provide for formation of an amide bond between the two reactive partners resulting in a final product comprising a phosphine moiety, or which can be engineered to comprise a cleavable linker so that a substituent of the phosphine is transferred to the azide, releasing an oxidized phosphine byproduct and producing a native amide bond in the final product. The selectivity of the reaction and its compatibility with aqueous environments provides for its application in vivo (e.g. on the cell surface or intracellularly) and in vitro (e.g., synthesis of peptides and other polymers, production of modified (e.g., labeled) amino acids).

  10. Chemoselective ligation

    Energy Technology Data Exchange (ETDEWEB)

    Saxon, Eliana (Albany, CA); Bertozzi, Carolyn Ruth (Berkeley, CA)

    2011-12-13

    The present invention features a chemoselective ligation reaction that can be carried out under physiological conditions. In general, the invention involves condensation of a specifically engineered phosphine, which can provide for formation of an amide bond between the two reactive partners resulting in a final product comprising a phosphine moiety, or which can be engineered to comprise a cleavable linker so that a substituent of the phosphine is transferred to the azide, releasing an oxidized phosphine byproduct and producing a native amide bond in the final product. The selectivity of the reaction and its compatibility with aqueous environments provides for its application in vivo (e.g., on the cell surface or intracellularly) and in vitro (e.g., synthesis of peptides and other polymers, production of modified (e.g., labeled) amino acids).

  11. Chemoselective ligation

    Energy Technology Data Exchange (ETDEWEB)

    Saxon, Eliana (Albany, CA); Bertozzi, Carolyn Ruth (Berkeley, CA)

    2010-11-23

    The present invention features a chemoselective ligation reaction that can be carried out under physiological conditions. In general, the invention involves condensation of a specifically engineered phosphine, which can provide for formation of an amide bond between the two reactive partners resulting in a final product comprising a phosphine moiety, or which can be engineered to comprise a cleavable linker so that a substituent of the phosphine is transferred to the azide, releasing an oxidized phosphine byproduct and producing a native amide bond in the final product. The selectivity of the reaction and its compatibility with aqueous environments provides for its application in vivo (e.g., on the cell surface or intracellularly) and in vitro (e.g., synthesis of peptides and other polymers, production of modified (e.g., labeled) amino acids).

  12. Chemoselective ligation

    Energy Technology Data Exchange (ETDEWEB)

    Saxon, Eliana (Albany, CA); Bertozzi, Carolyn R. (Berkeley, CA)

    2011-05-10

    The present invention features a chemoselective ligation reaction that can be carried out under physiological conditions. In general, the invention involves condensation of a specifically engineered phosphine, which can provide for formation of an amide bond between the two reactive partners resulting in a final product comprising a phosphine moiety, or which can be engineered to comprise a cleavable linker so that a substituent of the phosphine is transferred to the azide, releasing an oxidized phosphine byproduct and producing a native amide bond in the final product. The selectivity of the reaction and its compatibility with aqueous environments provides for its application in vivo (e.g., on the cell surface or intracellularly) and in vitro (e.g., synthesis of peptides and other polymers, production of modified (e.g., labeled) amino acids).

  13. Chemoselective ligation

    Energy Technology Data Exchange (ETDEWEB)

    Saxon, Eliana (Albany, CA); Bertozzi, Carolyn R. (Berkeley, CA)

    2011-04-12

    The present invention features a chemoselective ligation reaction that can be carried out under physiological conditions. In general, the invention involves condensation of a specifically engineered phosphine, which can provide for formation of an amide bond between the two reactive partners resulting in a final product comprising a phosphine moiety, or which can be engineered to comprise a cleavable linker so that a substituent of the phosphine is transferred to the azide, releasing an oxidized phosphine byproduct and producing a native amide bond in the final product. The selectivity of the reaction and its compatibility with aqueous environments provides for its application in vivo (e.g., on the cell surface or intracellularly) and in vitro (e.g., synthesis of peptides and other polymers, production of modified (e.g., labeled) amino acids).

  14. Exactly Embedded Wavefunction Methods for Characterizing Nitrogen Reduction Catalysis

    Science.gov (United States)

    2015-01-15

    AFRL-OSR-VA-TR-2015-0038 Exactly Embedded Wavefunction Methods for Characterizing Nitrogen THOMAS MILLER CALIFORNIA INSTITUTE OF TECHNOLOGY Final...SUBTITLE Exactly Embedded Wavefunction Methods for Characterizing Nitrogen Reduction Catalysis 5a. CONTRACT NUMBER N/A 5b. GRANT NUMBER FA9550...of developing and applying exactly embedded density functional and wavefunction theory methods for the investigation of small-molecular activation

  15. Synthesis and Characterization of Nitrogen-Doped Graphene

    OpenAIRE

    Palaniuk, D. Ryan

    2012-01-01

    Approved for public release; distribution is unlimited Self standing nitrogen doped graphene sheets were produced by reduction-expansion method, which utilizes graphite oxide (GO) and urea as precursor materials. For comparison, an Atmospheric Microwave Plasma Torch system (ATP) was used to produce graphene samples under argon and nitrogen atmospheres from GO. Graphene samples were characterized by XRD, TEM, SEM, BET and Raman Spectroscopy. The GO and urea mixtures decomposition-reduction ...

  16. Medial plantar nerve ligation as a novel model of neuropathic pain in mice: pharmacological and molecular characterization

    Science.gov (United States)

    Sant’Anna, Morena B.; Kusuda, Ricardo; Bozzo, Tiago A.; Bassi, Gabriel S.; Alves-Filho, José C.; Cunha, Fernando Q.; Ferreira, Sergio H.; Souza, Guilherme R.; Cunha, Thiago M.

    2016-01-01

    Peripheral neuropathic pain is a consequence of an injury/disease of the peripheral nerves. The mechanisms involved in its pathophysiology are not entirely understood. To better understand the mechanisms involved in the development of peripheral nerve injury-induced neuropathic pain, more experimental models are required. Here, we developed a novel peripheral neuropathic pain model in mice by using a minimally invasive surgery and medial plantar nerve ligation (MPNL). After MPNL, mechanical allodynia was established, and mice quickly recovered from the surgery without any significant motor impairment. MPNL causes an increased expression of ATF-3 in the sensory neurons. At 14 days after surgery, gabapentin was capable of reversing the mechanical allodynia, whereas anti-inflammatory drugs and opioids were ineffective. MPNL-induced neuropathic pain was mediated by glial cells activation and the production of TNF-α and IL-6 in the spinal cord. These results indicate MPNL as a reasonable animal model for the study of peripheral neuropathic pain, presenting analgesic pharmacological predictivity to clinically used drugs. The results also showed molecular phenotypic changes similar to other peripheral neuropathic pain models, with the advantage of a lack of motor impairment. These features indicate that MPNL might be more appropriate for the study of neuropathic pain than classical models. PMID:27230787

  17. Improvements to the Characterization of Organic Nitrogen Chemistry

    Science.gov (United States)

    Excess atmospheric nitrogen deposition can cause significant harmful effects to ecosystems. Organic nitrogen deposition can be an important contributor to the total nitrogen budget, contributing 10-30%, however there are large uncertainties in the chemistry and deposition of thes...

  18. Characterization of Nitrogen use efficiency in sweet sorghum

    Energy Technology Data Exchange (ETDEWEB)

    Dweikat, Ismail [University of Nebraska; Clemente, Thomas [University of Nebrask

    2014-09-09

    Sweet sorghum (Sorghum bicolor L. Moench) has the potential to augment the increasing demand for alternative fuels and for the production of input efficient, environmentally friendly bioenergy crops. Nitrogen (N) and water availability are considered two of the major limiting factors in crop growth. Nitrogen fertilization accounts for about 40% of the total production cost in sorghum. In cereals, including sorghum, the nitrogen use efficiency (NUE) from fertilizer is approximately 33% of the amount applied. There is therefore extensive concern in relation to the N that is not used by the plant, which is lost by leaching of nitrate, denitrification from the soil, and loss of ammonia to the atmosphere, all of which can have deleterious environmental effects. To improve the potential of sweet sorghum as a leading and cost effective bioenergy crop, the enhancement of NUE must be addressed. To this end, we have identified a sorghum line (SanChi San) that displays about 25% increase in NUE over other sorghum lines. As such, the overarching goal of this project is to employ three complementary strategies to enhance the ability of sweet sorghum to become an efficient nitrogen user. To achieve the project goal, we will pursue the following specific objectives: Objective 1: Phenotypic characterization of SanChi San/Ck60 RILs under low and moderate N-availability including biochemical profiles, vegetative growth and seed yield Objective 2: Conduct quantitative trait loci (QTL) analysis and marker identification for nitrogen use efficiency (NUE) in a grain sorghum RIL population. Objective 3: Identify novel candidate genes for NUE using proteomic and gene expression profiling comparisons of high- and low-NUE RILs. Candidate genes will be brought into the pipeline for transgenic manipulation of NUE This project will apply the latest genomics resources to discover genes controlling NUE, one of the most complex and economically important traits in cereal crops. As a result of the

  19. Electronic Configuration of Five-Coordinate High-Spin Pyrazole-Ligated Iron(II) Porphyrinates

    Science.gov (United States)

    Hu, Chuanjiang; Noll, Bruce C.; Schulz, Charles E.; Scheidt, W. Robert

    2010-01-01

    Pyrazole, a neutral nitrogen ligand and an isomer of imidazole, has been used as a fifth ligand to prepare two new species, [Fe(TPP)(Hdmpz)] and [Fe(Tp-OCH3PP)(Hdmpz)] (Hdmpz = 3,5-dimethylpyrazole), the first structurally characterized examples of five-coordinate iron(II) porphyrinates with a nonimidazole neutral ligand. Both complexes are characterized by X-ray crystallography, and structures show common features for five-coordinate iron(II) species, such as an expanded porphinato core, large equatorial Fe–Np bond distances and a significant out-of-plane displacement of the iron(II) atom. The Fe–N(pyrazole) and Fe–Np bond distances are similar to those in imidazole-ligated species. These suggest that the coordination abilities to iron(II) for imidazole and pyrazole are very similar even though pyrazole is less basic than imidazole. Mössbauer studies reveal that [Fe(TPP)(Hdmpz)] has the same behavior as those of imidazole-ligated species, such as negative quadrupole splitting values and relative large asymmetry parameters. Both the structures and Mössbauer spectra suggest pyrazole-ligated five-coordinate iron(II) porphyrinates have the same electronic configuration as imidazole-ligated species. PMID:21047081

  20. Electronic configuration of five-coordinate high-spin pyrazole-ligated iron(II) porphyrinates.

    Science.gov (United States)

    Hu, Chuanjiang; Noll, Bruce C; Schulz, Charles E; Scheidt, W Robert

    2010-12-06

    Pyrazole, a neutral nitrogen ligand and an isomer of imidazole, has been used as a fifth ligand to prepare two new species, [Fe(TPP)(Hdmpz)] and [Fe(Tp-OCH(3)PP)(Hdmpz)] (Hdmpz = 3,5-dimethylpyrazole), the first structurally characterized examples of five-coordinate iron(II) porphyrinates with a nonimidazole neutral ligand. Both complexes are characterized by X-ray crystallography, and structures show common features for five-coordinate iron(II) species, such as an expanded porphyrinato core, large equatorial Fe-N(p) bond distances, and a significant out-of-plane displacement of the iron(II) atom. The Fe-N(pyrazole) and Fe-N(p) bond distances are similar to those in imidazole-ligated species. These suggest that the coordination abilities to iron(II) for imidazole and pyrazole are very similar even though pyrazole is less basic than imidazole. Mössbauer studies reveal that [Fe(TPP)(Hdmpz)] has the same behavior as those of imidazole-ligated species, such as negative quadrupole splitting values and relative large asymmetry parameters. Both the structures and the Mössbauer spectra suggest pyrazole-ligated five-coordinate iron(II) porphyrinates have the same electronic configuration as imidazole-ligated species.

  1. Synthesis and Preliminary Characterization of a PPE-Type Polymer Containing Substituted Fullerenes and Transition Metal Ligation Sites

    Directory of Open Access Journals (Sweden)

    Corinne A. Basinger

    2015-01-01

    Full Text Available A substituted fullerene was incorporated into a PPE-conjugated polymer repeat unit. This subunit was then polymerized via Sonogashira coupling with other repeat units to create polymeric systems approaching 50 repeat units (based on GPC characterization. Bipyridine ligands were incorporated into some of these repeat units to provide sites for transition metal coordination. Photophysical characterization of the absorption and emission properties of these systems shows excited states located on both the fullerene and aromatic backbone of the polymers that exist in a thermally controlled equilibrium. Future work will explore other substituted polyaromatic systems using similar methodologies.

  2. Metal complexes of the nanosized ligand N-benzoyl-N‧-(p-amino phenyl) thiourea: Synthesis, characterization, antimicrobial activity and the metal uptake capacity of its ligating resin

    Science.gov (United States)

    Elhusseiny, Amel F.; Eldissouky, Ali; Al-Hamza, Ahmed M.; Hassan, Hammed H. A. M.

    2015-11-01

    The new nanosized N-benzoyl-N‧-(p-amino phenyl) thiourea ligand H2L was synthesized by nanoprecipitation method. The [Cu (H2L)2 Cl]·2H2O, [Zn (H2L)2(OAc)2], [Cd (H2L)2Cl2] and [Hg (H2L)2Cl2] complexes were synthesized and characterized by various physicochemical methods. Results revealed that the ligand act as hypodentate and bonded to the metal ion via the sulfur atom forming mononuclear non-electrolyte diamagnetic complex. Magnetic moment results indicated a reduction of Cu (II) to Cu (I) during the coordination process. Thermal studies demonstrated variable stabilities of the complexes and [Zn (H2L)2(OAc)2] exhibited the highest thermal stability while [Hg (H2L)2Cl2] was volatile. The prepared compounds were screened against different pathogenic microorganisms. The ligand performed high antibacterial activity against certain bacterial strain compared to its complexes, and the standard bacteriocide in use. The ligand was successfully immobilized on modified Amberlite XAD-16 forming the hypodentate ligating resin PS-SO2-H2L. The new resin was characterized and the extent of metal adsorption reached maximum at pH 6.0 for Cu (II), Cd (II) and Ag (I), with an adsorption amount of 4.3, 4.0 and 3.7 mmol g-1 respectively. The nanosized H2L represents a new category of promising adsorbent that would have a practical impact on biological and water treatment applications.

  3. Nitrogen

    Science.gov (United States)

    Apodaca, Lori E.

    2013-01-01

    The article presents an overview of the nitrogen chemical market as of July 2013, including the production of ammonia compounds. Industrial uses for ammonia include fertilizers, explosives, and plastics. Other topics include industrial capacity of U.S. ammonia producers CF Industries Holdings Inc., Koch Nitrogen Co., PCS Nitrogen, Inc., and Agrium Inc., the impact of natural gas prices on the nitrogen industry, and demand for corn crops for ethanol production.

  4. Characterization of nitrogen species incorporated into graphite using low energy nitrogen ion sputtering.

    Science.gov (United States)

    Kiuchi, Hisao; Kondo, Takahiro; Sakurai, Masataka; Guo, Donghui; Nakamura, Junji; Niwa, Hideharu; Miyawaki, Jun; Kawai, Maki; Oshima, Masaharu; Harada, Yoshihisa

    2016-01-01

    The electronic structures of nitrogen species incorporated into highly oriented pyrolytic graphite (HOPG), prepared by low energy (200 eV) nitrogen ion sputtering and subsequent annealing at 1000 K, were investigated by X-ray photoelectron spectroscopy (XPS), angle-dependent X-ray absorption spectroscopy (XAS), and Raman spectroscopy. An additional peak was observed at higher binding energy of 401.9 eV than 400.9 eV for graphitic1 N (graphitic N in the basal plane) in N 1s XPS, where graphitic2 N (graphitic N in the zigzag edge and/or vacancy sites) has been theoretically expected to appear. N 1s XPS showed that graphitic1 N and graphitic2 N were preferably incorporated under low nitrogen content doping conditions (8 × 10(13) ions cm(-2)), while pyridinic N and graphitic1 N were dominantly observed under high nitrogen content doping conditions. In addition, angle-dependent N 1s XAS showed that the graphitic N and pyridinic N atoms were incorporated into the basal plane of HOPG and thus were highly oriented. Furthermore, Raman spectroscopy revealed that low energy sputtering resulted in almost no fraction of the disturbed graphite surface layers under the lowest nitrogen doping condition. The suitable nitrogen doping condition was discovered for realizing the well-controlled nitrogen doped HOPG. The electrochemical properties for the oxygen reduction reaction of these samples in acidic solution were examined and discussed.

  5. Nitrogen doped carbon nanotubes : synthesis, characterization and catalysis

    NARCIS (Netherlands)

    van Dommele, S.

    2008-01-01

    Nitrogen containing Carbon Nanotubes (NCNT) have altered physical- and chemical properties with respect to polarity, conductivity and reactivity as compared to conventional carbon nanotubes (CNT) and have potential for use in electronic applications or catalysis. In this thesis the incorporation of

  6. Evaluation of cerebral electrical activity and cardiac output after patent ductus arteriosus ligation in preterm infants.

    LENUS (Irish Health Repository)

    Leslie, A T F S

    2013-11-01

    To characterize and investigate the relationship between systemic blood flow and pre- and postoperative cerebral electrical activity in preterm neonates undergoing patent ductus arteriosus (PDA) ligation.

  7. Production and characterization of a nitrogen-implanted Fe standard to calibrate PIGE measurements

    Science.gov (United States)

    Rodrigues, C. L.; Silva, T. F.; Added, N.; Santos, H. C.; Tabacniks, M. H.

    2014-11-01

    Three calibration standard was produced by ion implantation of nitrogen in samples of Armco iron (99.7% iron). The samples was irradiated with nitrogen ion beams at several different energies (between 4 keV and 40 keV), and the ion doses were adjusted to obtain an uniform depth profile, using simulations with SRIM code. Two standards, one thick and other a foil (1.62mg/cm2), was irradiated at same time with total nominal dose of 6.6×10-16 atoms/cm2 distributed in a region of 100 nm in depth, with an average concentration of 9.0% nitrogen in iron. The third sample uses the same profile, but with a small dose, 1.1×10-16 atoms/cm2 and average concentration of 1.5% nitrogen. The characterization of the implanted samples was done using RBS and NRA techniques to quantification of nitrogen.

  8. Characterization of narrow micropores in almond shell biochars by nitrogen, carbon dioxide, and hydrogen adsorption

    Science.gov (United States)

    Characterization of biochars usually includes surface area and pore volume determination by nitrogen adsorption. In this study, we show that there is a substantial pore volume in biochars created via slow pyrolysis from low- and high-ash almond shells that cannot be characterized in this fashion due...

  9. Preparation and characterization of nitrogen-doped titanium dioxides

    Institute of Scientific and Technical Information of China (English)

    ZHU GuoPing; ZHOU KangGen

    2007-01-01

    A type of high visible-light active titanium oxinitride (TiO2_xNx) powder was prepared by a simple process: the calcination of the hydrated titanium dioxide at the atmosphere of ammonia-argon using a tubular electric furnace at high temperatures. The hydrated titanium dioxide was synthesized as the precursor of TiO2_xNx using titanic acid as raw material, which came from sulfate technique of producing titanium white. The effects of temperature and reaction time on the nitrogen content, grain size and crystal structure were studied. The visible-light activity and photocatalysis capability of the powder were also investigated.

  10. Preparation and characterization of nitrogen-doped titanium dioxides

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A type of high visible-light active titanium oxinitride(TiO2-xNx) powder was prepared by a simple proc-ess:the calcination of the hydrated titanium dioxide at the atmosphere of ammonia-argon using a tu-bular electric furnace at high temperatures. The hydrated titanium dioxide was synthesized as the precursor of TiO2-xNx using titanic acid as raw material,which came from sulfate technique of produc-ing titanium white. The effects of temperature and reaction time on the nitrogen content,grain size and crystal structure were studied. The visible-light activity and photocatalysis capability of the powder were also investigated.

  11. Characterization of La/Fe/TiO2 and Its Photocatalytic Performance in Ammonia Nitrogen Wastewater

    Directory of Open Access Journals (Sweden)

    Xianping Luo

    2015-11-01

    Full Text Available La/Fe/TiO2 composite photocatalysts were synthesized by Sol-Gel method and well characterized by powder X-ray diffraction (XRD, scanning electron microscopy (SEM, nitrogen-physical adsorption, and UV-Vis diffuse reflectance spectra (UV-Vis DRS. It is interesting that the doped catalysts were in anatase phase while the pure TiO2 was in rutile phase. In addition, the composites possessed better physical chemical properties in photocatalytic activity than pure TiO2: stronger visible-light-response ability, larger specific surface area, and more regular shape in morphology. The photodegradation results of ammonia nitrogen indicate that: the La/Fe/TiO2 had higher catalytic activity to ammonia nitrogen waste water compared pure TiO2 and the other single metal-doped TiO2. pH 10 and 2 mmol/L H2O2 were all beneficial to the removal of ammonia nitrogen by La/Fe/TiO2. However, the common inorganic ions of Cl−, NO3−, SO42−, HCO3−/CO32−, Na+, K+, Ca2+ and Mg2+ in water all inhibited the degradation of ammonia nitrogen. By balance calculation, at least 20% of ammonia nitrogen was converted to N2 during the 64.6% removal efficiency of ammonia nitrogen.

  12. Characterization of La/Fe/TiO₂ and Its Photocatalytic Performance in Ammonia Nitrogen Wastewater.

    Science.gov (United States)

    Luo, Xianping; Chen, Chunfei; Yang, Jing; Wang, Junyu; Yan, Qun; Shi, Huquan; Wang, Chunying

    2015-11-01

    La/Fe/TiO₂ composite photocatalysts were synthesized by Sol-Gel method and well characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), nitrogen-physical adsorption, and UV-Vis diffuse reflectance spectra (UV-Vis DRS). It is interesting that the doped catalysts were in anatase phase while the pure TiO₂ was in rutile phase. In addition, the composites possessed better physical chemical properties in photocatalytic activity than pure TiO₂: stronger visible-light-response ability, larger specific surface area, and more regular shape in morphology. The photodegradation results of ammonia nitrogen indicate that: the La/Fe/TiO₂ had higher catalytic activity to ammonia nitrogen waste water compared pure TiO₂ and the other single metal-doped TiO₂. pH 10 and 2 mmol/L H₂O₂ were all beneficial to the removal of ammonia nitrogen by La/Fe/TiO₂. However, the common inorganic ions of Cl(-), NO₃(-), SO₄(2-), HCO₃(-)/CO₃²(-), Na⁺, K⁺, Ca(2+) and Mg(2+) in water all inhibited the degradation of ammonia nitrogen. By balance calculation, at least 20% of ammonia nitrogen was converted to N₂ during the 64.6% removal efficiency of ammonia nitrogen.

  13. Characterization of La/Fe/TiO2 and Its Photocatalytic Performance in Ammonia Nitrogen Wastewater

    Science.gov (United States)

    Luo, Xianping; Chen, Chunfei; Yang, Jing; Wang, Junyu; Yan, Qun; Shi, Huquan; Wang, Chunying

    2015-01-01

    La/Fe/TiO2 composite photocatalysts were synthesized by Sol-Gel method and well characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), nitrogen-physical adsorption, and UV-Vis diffuse reflectance spectra (UV-Vis DRS). It is interesting that the doped catalysts were in anatase phase while the pure TiO2 was in rutile phase. In addition, the composites possessed better physical chemical properties in photocatalytic activity than pure TiO2: stronger visible-light-response ability, larger specific surface area, and more regular shape in morphology. The photodegradation results of ammonia nitrogen indicate that: the La/Fe/TiO2 had higher catalytic activity to ammonia nitrogen waste water compared pure TiO2 and the other single metal-doped TiO2. pH 10 and 2 mmol/L H2O2 were all beneficial to the removal of ammonia nitrogen by La/Fe/TiO2. However, the common inorganic ions of Cl−, NO3−, SO42−, HCO3−/CO32−, Na+, K+, Ca2+ and Mg2+ in water all inhibited the degradation of ammonia nitrogen. By balance calculation, at least 20% of ammonia nitrogen was converted to N2 during the 64.6% removal efficiency of ammonia nitrogen. PMID:26593929

  14. Photoluminescence and Raman spectroscopy characterization of boron- and nitrogen-doped 6H silicon carbide

    DEFF Research Database (Denmark)

    Ou, Yiyu; Jokubavicius, Valdas; Liu, Chuan

    2011-01-01

    Boron - and nitrogen-doped 6H silicon carbide epilayers grown on low off-axis 6H silicon carbide substrates have been characterized by photoluminescence and Raman spectroscopy. Combined with secondary ion mass spectrometry results, preferable doping type and optimized concentration could...

  15. Production and characterization of a nitrogen-implanted Fe standard to calibrate PIGE measurements

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, C. L.; Silva, T. F.; Added, N.; Santos, H. C.; Tabacniks, M. H. [Institute of Physics - University of São Paulo (Brazil)

    2014-11-11

    Three calibration standard was produced by ion implantation of nitrogen in samples of Armco iron (99.7% iron). The samples was irradiated with nitrogen ion beams at several different energies (between 4 keV and 40 keV), and the ion doses were adjusted to obtain an uniform depth profile, using simulations with SRIM code. Two standards, one thick and other a foil (1.62mg/cm{sup 2}), was irradiated at same time with total nominal dose of 6.6×10{sup −16} atoms/cm{sup 2} distributed in a region of 100 nm in depth, with an average concentration of 9.0% nitrogen in iron. The third sample uses the same profile, but with a small dose, 1.1×10{sup −16} atoms/cm{sup 2} and average concentration of 1.5% nitrogen. The characterization of the implanted samples was done using RBS and NRA techniques to quantification of nitrogen.

  16. Characterization of brazilian wheat cultivars in terms of nitrogen use efficiency

    Directory of Open Access Journals (Sweden)

    Cristiano Lemes da Silva

    2014-06-01

    Full Text Available Nitrogen (N management in wheat crop is one of the most studied agricultural practices in Brazil; however, there are few reports on its use efficiency. The objective of this study was to characterize 18 Brazilian wheat cultivars, which are representative and have been recently released to cultivation, for nitrogen use efficiency (NUE. The experiments were carried out in Pato Branco, Paraná, and Coxilha, Rio Grande do Sul, during the 2011 crop season. It was used a randomized block design with three replications, in factorial scheme (2 environments × 18 cultivars. Genetic variability was observed for nitrogen utilization efficiency by grains (NUtEg=47.6 to 81.1 kg kg-1 and nitrogen harvest index (NHI=71.3 to 84.6% with significant effects relating to the environment of cultivation and performance of these traits. The evaluation of the protein concentration of grain by near infrared spectrometry (GPC N produced equivalent results to the direct analytical method of Kjeldahl (GPC K, in Pato Branco (r=0.56 and Coxilha (RS (r=0.80. However the CPG N overestimated the protein values by 16.85%. The GPC and protein yield were positively correlated with NUtEg and NHI. The best performance for the traits associated with NUE was observed for the following cultivars: Mirante, Quartzo, Fundacep Cristalino, Fundacep Raízes and CD 150. This is the first report of differences between Brazilian wheat cultivars for nitrogen use efficiency.

  17. [Post-tubal ligation syndrome].

    Science.gov (United States)

    Satoh, K; Osada, H

    1993-01-01

    Post-tubal ligation syndrome includes pain during intercourse, aching lower back, premenstrual tension syndrome, difficulty in menstruating, uterine hemorrhage, and absence of menstruation. The syndrome is caused by blood circulation problems in and around the Fallopian tubes and ovaries, pressure on nerves, and intrapelvic adhesion. Differentiating between this syndrome and endometritis during diagnosis and differentiating between functional hemorrhage due to hormonal abnormality and anatomical hemorrhage due to polyp or tumor is very important. Since the symptoms of this syndrome are mild, simple symptomatic treatment is sufficient in most cases. In some cases, however, desquamation surgery or reversal of tubal ligation may be necessary. Endoscopic surgery is also available. In Japan, because of widespread use of condoms and IUDs, tubal ligation is not very common.

  18. Characterization of free nitrogen fixing bacteria of the genus Azotobacter in organic vegetable-grown Colombian soils

    NARCIS (Netherlands)

    Jiménez Avella, Diego; Montaña, José Salvador; Martínez, María Mercedes

    2011-01-01

    With the purpose of isolating and characterizing free nitrogen fixing bacteria (FNFB) of the genus Azotobacter, soil samples were collected randomly from different vegetable organic cultures with neutral pH in different zones of Boyacá-Colombia. Isolations were done in selective free nitrogen Ashby-

  19. Ligation-assisted endoscopic mucosal resection of gastric heterotopic pancreas

    Institute of Scientific and Technical Information of China (English)

    Mouen A Khashab; Oscar W Cummings; John M DeWitt

    2009-01-01

    Heterotopic pancreas is a congenital anomaly characterized by ectopic pancreatic tissue.Treatment of heterotopic pancreas may include expectant observation,endoscopic resection or surgery.The aim of this report was to describe the technique of ligation-assisted endoscopic mucosal resection (EMR) for resection of heterotopic pancreas of the stomach.Two patients (both female,mean age 32 years) were referred for management of gastric subepithelial tumors.Endoscopic ultrasound in both disclosed small hypoechoic masses in the mucosa and submucosa.Band ligation-assisted EMR was performed in both cases without complications.Pathology from the resected tumors revealed heterotopic pancreas arising from the submucosa.Margins were free of pancreatic tissue.Ligation-assisted EMR is technically feasible and may be considered for the endoscopic management of heterotopic pancreas.

  20. Ligation-Independent Mechanism of Multiplex Ligation-Dependent Probe Amplification

    OpenAIRE

    Uno, Naoki; Yanagihara, Katsunori

    2014-01-01

    Multiplex ligation-dependent probe amplification (MLPA) is a widely used technique for detecting genomic structural variants. The technique is based on hybridization and ligation, followed by amplification of the ligation products. Therefore, ligation is considered a fundamental process that determines the feasibility and fidelity of MLPA. However, despite the widespread use of this technique, its reaction mechanism has not been fully analyzed. Herein, we describe a ligation-independent pathw...

  1. Zinc acetylacetonate hydrate adducted with nitrogen donor ligands: Synthesis, spectroscopic characterization, and thermal analysis

    Science.gov (United States)

    Brahma, Sanjaya; Shivashankar, S. A.

    2015-12-01

    We report synthesis, spectroscopic characterization, and thermal analysis of zinc acetylacetonate complex adducted by nitrogen donor ligands, such as pyridine, bipyridine, and phenanthroline. The pyridine adducted complex crystallizes to monoclinic crystal structure, whereas other two adducted complexes have orthorhombic structure. Addition of nitrogen donor ligands enhances the thermal property of these complexes as that with parent metal-organic complex. Zinc acetylacetonate adducted with pyridine shows much higher volatility (106 °C), decomposition temperature (202 °C) as that with zinc acetylacetonate (136 °C, 220 °C), and other adducted complexes. All the adducted complexes are thermally stable, highly volatile and are considered to be suitable precursors for metal organic chemical vapor deposition. The formation of these complexes is confirmed by powder X-ray diffraction, Fourier transform infrared spectroscopy, mass spectroscopy, and elemental analysis. The complexes are widely used as starting precursor materials for the synthesis of ZnO nanostructures by microwave irradiation assisted coating process.

  2. The postal tubal ligation syndrome.

    Science.gov (United States)

    Faber, E; Rocko, J M; Timmes, J J; Zolli, A F

    1981-01-01

    The frequency of symptoms following tubal ligation calls for an examination of the basic problem with the methods now used. This discussion recommends a modification of tubal ligation which as performed during the past 2-1/2 years has been symptom free, post operatively. What is meant by symptom free is those symptoms which can be directly related to tubal ligation. Symptomatology is complex and insidious. Characteristically, there is a latent period of no symptoms. This asymptomatic period may be totally subjective and may last several years during which time the correlation between surgery and symptoms is obscured. This is particularly the case if purely symptomatic therapeusis has had some degree of success. The latest period is followed by the gradual development of the following: menstrual disorders; abdominal pain which is usually located in the lower abdomen and is of 2 varieties, i.e., dysmenorrhea and nonmenstrual pain; and infection. Physical examination demonstrates little. This set of symptoms, which has been documented also by Poma et al., and when taken as a whole, constitutes a syndrome which should be termed the posttubal ligation syndrome. These patients give a history of repeat X-rays, biopsies, endoscopies, and surgical exploration. Some of these patients have had 4 or 5 celiotomies. A modification of the traditional method of tubal ligation definitely requires consideration. The characteristics of the oviducts which need mention and emphasis are reviewed. On the basis of the reviewed considerations, it becomes obvious that smooth transport of the ovum is a necessity and that obstruction in the tubes will cause a reaction similar to obstruction anywhere in the body. Tubal ligation should be performed in such a manner so as not to obstruct the ova from passing down the tube. The tubes should be cut fairly close to the uterus and be tied. The rest of the tube from fimbria to the isthmus should be left open. In this manner, the ovum passes into the

  3. [Latex ligation in treatment of chronic hemorrhoids].

    Science.gov (United States)

    Ektov, V N; Somov, K A

    2015-01-01

    We analyzed the results of treatment of 432 patients with chronic hemorrhoids using different variants of latex ligation. New technique including ligation of mucosa and submucosa of low-ampullar rectum providing ligation of hemorrhoidalvessels, lifting and recto-anal repair is developed and suggested. This method is advisable to use in case of chronic internal hemorrhoids stages I and II. The authors recommend simultaneous combined ligation of mucosa of low-ampullar rectum and internal hemorrhoids for stages III and IV. Different variants of latex ligation with external hemorrhoids excision were used in 103 patients. Pointed variants of latex ligation preserve important advantages including mini-invasiveness, simplicity and wide availability, low cost. Good remote results were obtained after these procedures in 87.3% of observations. Suggested tactics extends use of latex ligation and increases its effectiveness in treatment of different stages and forms of chronic hemorrhoids.

  4. Synthesis and Characterization of Phosphine and Arsine Complexes of Ruthenium (Ii & Iii Ligated With 3-(4-Pyridyl-4-Substituted-Triazoline-5-Thione

    Directory of Open Access Journals (Sweden)

    R. N. Pandey

    2014-12-01

    Full Text Available Organometallic complexes of ruthenium (II & III with the formula [RuH(CO(Ef32L] and [RuCl2(Ef32L] (E = P/As; L = deprotonated mononegative bidentate 3-(4-pyridyl-triazoline-5-thione and its 4-phenyl substituted derivative were synthesized and characterized by elemental analysis, physico-chemical and spectroscopic methods. All new compounds were iso-structural with precursor complexes. Two triphenyl phosphine or triphenylarsine molecules are at trans-disposition and thioamide ligands behaves as bidentate (N, S donor in assigned octahedral structure.

  5. Synthesis and characterization of ligational behavior of curcumin drug towards some transition metal ions: Chelation effect on their thermal stability and biological activity

    Science.gov (United States)

    Refat, Moamen S.

    2013-03-01

    Complexes of Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) with curcumin ligand as antitumor activity were synthesized and characterized by elemental analysis, conductometry, magnetic susceptibility, UV-Vis, IR, Raman, ESR, 1H-NMR spectroscopy, X-ray diffraction analysis of powdered samples and thermal analysis, and screened for antimicrobial activity. The IR spectral data suggested that the ligand behaves as a monobasic bidentate ligand towards the central metal ion with an oxygen's donor atoms sequence of both sbnd OH and Cdbnd O groups under keto-enol structure. From the microanalytical data, the stoichiometry of the complexes 1:2 (metal:ligand) was found. The ligand and their metal complexes were screened for antibacterial activity against Escherichia Coli, Staphylococcus aureus, Bacillus subtilis and Pseudomonas aeruginosa and fungicidal activity against Aspergillus flavus and Candida albicans.

  6. Characterization of nitrogen doped silicon-carbon multi-layer nanostructures obtained by TVA method

    Science.gov (United States)

    Ciupina, Victor; Vasile, Eugeniu; Porosnicu, Corneliu; Prodan, Gabriel C.; Lungu, Cristian P.; Vladoiu, Rodica; Jepu, Ionut; Mandes, Aurelia; Dinca, Virginia; Caraiane, Aureliana; Nicolescu, Virginia; Dinca, Paul; Zaharia, Agripina

    2016-09-01

    Ionized nitrogen doped Si-C multi-layer thin films used to increase the oxidation resistance of carbon have been obtained by Thermionic Vacuum Arc (TVA) method. The 100 nm thickness carbon thin films were deposed on silicon or glass substrates and then seven N doped Si-C successively layers on carbon were deposed. To characterize the microstructure, tribological and electrical properties of as prepared N-SiC multi-layer films, Transmission Electron Microscopy (TEM, STEM), Energy Dispersive X-Ray Spectroscopy (EDXS), electrical and tribological techniques were achieved. Samples containing multi-layer N doped Si-C coating on carbon were investigated up to 1000°C. Oxidation protection is based on the reaction between SiC and elemental oxygen, resulting SiO2 and CO2, and also on the reaction involving N, O and Si-C, resulting silicon oxynitride (SiNxOy) with a continuously vary composition, and because nitrogen can acts as a trapping barrier for oxygen. The tribological properties of structures were studied using a tribometer with ball-on-disk configuration from CSM device with sapphire ball. The measurements show that the friction coefficient on the N-SiC is smaller than friction coefficient on uncoated carbon layer. Electrical conductivity at different temperatures was measured in constant current mode. The results confirm the fact that conductivity is greater when nitrogen content is greater. To justify the temperature dependence of conductivity we assume a thermally activated electrical transport mechanism.

  7. Synthesis, characterization, photocatalysis, and varied properties of TiO2 cosubstituted with nitrogen and fluorine.

    Science.gov (United States)

    Kumar, Nitesh; Maitra, Urmimala; Hegde, Vinay I; Waghmare, Umesh V; Sundaresan, A; Rao, C N R

    2013-09-16

    TiO2 (anatase) codoped with nitrogen and fluorine, synthesized by a simple solid state route, using urea and ammonium fluoride as sources of nitrogen and fluorine, respectively, as well as by decomposition of (NH4)2TiF6 for comparison, has been characterized by various techniques. XPS analysis shows the composition to be TiO1.7N0.18F0.12 for urea-based method (N, F-TiO2-urea) and TiO1.9N0.04F0.06 for complex decomposition method (N, F-TiO2-complex). Both the materials are defect-free as revealed by photoluminescence spectroscopy. Thus, N, F-TiO2-urea exhibits smaller defect-induced magnetization compared to the nitrogen-doped sample. Cosubstitution of N and F is accompanied with an enhancement of the absorption of light in the visible region giving rise to yellow color and with a band gap of ∼2.2 eV in the case of N, F-TiO2-urea. It exhibits enhanced photocatalytic activity and also significant hydrogen evolution (400 μmol/g) on interaction with visible light in the absence of any cocatalyst, which is much higher compared to N, F-TiO2-complex and N-TiO2. First-principles calculations show significant local distortions on codoping TiO2 with N and F and a lowering of energy by 1.93 eV per N, F pair. With virtual negative and positive charges on nitrogen and fluorine, respectively, the dopants prefer pairwise clustering. Our calculations predict a reduction in the band gap in TiO2 cosubstituted with nitrogen and fluorine. The calculated band structure shows that nitrogen 2p states form a separate subband just above the valence band which is enhanced on incorporation of fluorine. Our calculations also indicate anomalous Born effective charges in N, F-TiO2 and predict enhanced photocatalytic activity on codoping of TiO2 by N and F.

  8. Improvements to the characterization of organic nitrogen chemistry and deposition in CMAQ (CMAS Presentation)

    Science.gov (United States)

    Excess atmospheric nitrogen deposition can cause significant harmful effects to ecosystems. Organic nitrogen deposition can be an important contributor to the total nitrogen budget, contributing 10-30%, however there are large uncertainties in the chemistry and deposition of thes...

  9. Improvements to the characterization of organic nitrogen chemistry and deposition in CMAQ

    Science.gov (United States)

    Excess atmospheric nitrogen deposition can cause significant harmful effects to ecosystems. Organic nitrogen deposition can be an important contributor to the total nitrogen budget, contributing 10-30%, however there are large uncertainties in the chemistry and deposition of thes...

  10. Molecular characterization of nitrogen-fixing bacteria isolated from brazilian agricultural plants at São Paulo state

    Science.gov (United States)

    Reinhardt, Érica. L.; Ramos, Patrícia L.; Manfio, Gilson P.; Barbosa, Heloiza R.; Pavan, Crodowaldo; Moreira-Filho, Carlos A.

    2008-01-01

    Fourteen strains of nitrogen-fixing bacteria were isolated from different agricultural plant species, including cassava, maize and sugarcane, using nitrogen-deprived selective isolation conditions. Ability to fix nitrogen was verified by the acetylene reduction assay. All potentially nitrogen-fixing strains tested showed positive hybridization signals with a nifH probe derived from Azospirillum brasilense. The strains were characterized by RAPD, ARDRA and 16S rDNA sequence analysis. RAPD analyses revealed 8 unique genotypes, the remaining 6 strains clustered into 3 RAPD groups, suggesting a clonal origin. ARDRA and 16S rDNA sequence analyses allowed the assignment of 13 strains to known groups of nitrogen-fixing bacteria, including organisms from the genera Azospirillum, Herbaspirillum, Pseudomonas and Enterobacteriaceae. Two strains were classified as Stenotrophomonas ssp. Molecular identification results from 16S rDNA analyses were also corroborated by morphological and biochemical data. PMID:24031239

  11. Molecular characterization of nitrogen-fixing bacteria isolated from brazilian agricultural plants at São Paulo state.

    Science.gov (United States)

    Reinhardt, Erica L; Ramos, Patrícia L; Manfio, Gilson P; Barbosa, Heloiza R; Pavan, Crodowaldo; Moreira-Filho, Carlos A

    2008-07-01

    Fourteen strains of nitrogen-fixing bacteria were isolated from different agricultural plant species, including cassava, maize and sugarcane, using nitrogen-deprived selective isolation conditions. Ability to fix nitrogen was verified by the acetylene reduction assay. All potentially nitrogen-fixing strains tested showed positive hybridization signals with a nifH probe derived from Azospirillum brasilense. The strains were characterized by RAPD, ARDRA and 16S rDNA sequence analysis. RAPD analyses revealed 8 unique genotypes, the remaining 6 strains clustered into 3 RAPD groups, suggesting a clonal origin. ARDRA and 16S rDNA sequence analyses allowed the assignment of 13 strains to known groups of nitrogen-fixing bacteria, including organisms from the genera Azospirillum, Herbaspirillum, Pseudomonas and Enterobacteriaceae. Two strains were classified as Stenotrophomonas ssp. Molecular identification results from 16S rDNA analyses were also corroborated by morphological and biochemical data.

  12. Melanin from the nitrogen-fixing bacterium Azotobacter chroococcum: a spectroscopic characterization.

    Science.gov (United States)

    Banerjee, Aulie; Supakar, Subhrangshu; Banerjee, Raja

    2014-01-01

    Melanins, the ubiquitous hetero-polymer pigments found widely dispersed among various life forms, are usually dark brown/black in colour. Although melanins have variety of biological functions, including protection against ultraviolet radiation of sunlight and are used in medicine, cosmetics, extraction of melanin from the animal and plant kingdoms is not an easy task. Using complementary physicochemical techniques (i.e. MALDI-TOF, FTIR absorption and cross-polarization magic angle spinning solid-state (13)C NMR), we report here the characterization of melanins extracted from the nitrogen-fixing non-virulent bacterium Azotobacter chroococcum, a safe viable source. Moreover, considering dihydroxyindole moiety as the main constituent, an effort is made to propose the putative molecular structure of the melanin hetero-polymer extracted from the bacterium. Characterization of the melanin obtained from Azotobacter chroococcum would provide an inspiration in extending research activities on these hetero-polymers and their use as protective agent against UV radiation.

  13. Synthesis and characterization of nitrogen-doped carbon nanotubes by pyrolysis of melamine

    Science.gov (United States)

    Li, Xuefei; Kong, Lingnan; Yang, Jinghai; Gao, Ming; Hu, Tingjing; Wu, Xingtong; Li, Ming

    2013-11-01

    The typical bamboo-like nitrogen doped carbon nanotubes (N-CNTs) have been successfully synthesized via pyrolysis of melamine (C3N6H6). The morphology of the samples is characterized by field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The synthesized nanotubes are structurally uniform. The nitrogen to carbon atomic ratio of N-CNTs determined by chemical element analysis is found to be 0.23. The corresponding binding energy of the samples is obtained through X-ray photoelectron spectroscopy (XPS) and the characteristic infrared peaks are recorded by using Fourier transform infrared spectroscopy (FTIR). The characterization of thermal stability is obtained by thermo-gravimetric analysis (TGA) under flowing argon. The photoluminescence (PL) spectrum of the product shows that all the emission peaks are located in the blue-violet wavelength region, which indicates that N-CNTs may have potential applications in nano-optical device fields. Moreover, the growth mechanism of N-CNTs is carefully discussed.

  14. Natural clinoptilolite exchanged with iron: characterization and catalytic activity in nitrogen monoxide reduction

    Directory of Open Access Journals (Sweden)

    Daria Tito-Ferro

    2016-12-01

    Full Text Available The aim of this work was to characterize the natural clinoptilolite from Tasajeras deposit, Cuba, modified by hydrothermal ion-exchange with solutions of iron (II sulfate and iron (III nitrate in acid medium. Besides this, its catalytic activity to reduce nitrogen monoxide with carbon monoxide/propene in the presence of oxygen was evaluated. The characterization was performed by Mössbauer and UV-Vis diffuse reflectance spectroscopies and adsorption measurements. The obtained results lead to conclude that in exchanged samples, incorporated divalent and trivalent irons are found in octahedral coordination. Both irons should be mainly in cationic extra-framework positions inside clinoptilolite channels as charge compensating cations, and also as iron oxy-hydroxides resulting from limited hydrolysis of these cations. The iron (III exchanged samples has a larger amount of iron oxy-hydroxides agglomerates. The iron (II exchanged samples have additionally iron (II sulfate adsorbed. The catalytic activity in the nitrogen monoxide reduction is higher in the exchanged zeolites than starting. Among all samples, those exchanged of iron (II has the higher catalytic activity. This lead to outline that, main catalytically active centers are associated with divalent iron.

  15. Characterization of an Nmr homolog that modulates GATA factor-mediated nitrogen metabolite repression in Cryptococcus neoformans.

    Directory of Open Access Journals (Sweden)

    I Russel Lee

    Full Text Available Nitrogen source utilization plays a critical role in fungal development, secondary metabolite production and pathogenesis. In both the Ascomycota and Basidiomycota, GATA transcription factors globally activate the expression of catabolic enzyme-encoding genes required to degrade complex nitrogenous compounds. However, in the presence of preferred nitrogen sources such as ammonium, GATA factor activity is inhibited in some species through interaction with co-repressor Nmr proteins. This regulatory phenomenon, nitrogen metabolite repression, enables preferential utilization of readily assimilated nitrogen sources. In the basidiomycete pathogen Cryptococcus neoformans, the GATA factor Gat1/Are1 has been co-opted into regulating multiple key virulence traits in addition to nitrogen catabolism. Here, we further characterize Gat1/Are1 function and investigate the regulatory role of the predicted Nmr homolog Tar1. While GAT1/ARE1 expression is induced during nitrogen limitation, TAR1 transcription is unaffected by nitrogen availability. Deletion of TAR1 leads to inappropriate derepression of non-preferred nitrogen catabolic pathways in the simultaneous presence of favoured sources. In addition to exhibiting its evolutionary conserved role of inhibiting GATA factor activity under repressing conditions, Tar1 also positively regulates GAT1/ARE1 transcription under non-repressing conditions. The molecular mechanism by which Tar1 modulates nitrogen metabolite repression, however, remains open to speculation. Interaction between Tar1 and Gat1/Are1 was undetectable in a yeast two-hybrid assay, consistent with Tar1 and Gat1/Are1 each lacking the conserved C-terminus regions present in ascomycete Nmr proteins and GATA factors that are known to interact with each other. Importantly, both Tar1 and Gat1/Are1 are suppressors of C. neoformans virulence, reiterating and highlighting the paradigm of nitrogen regulation of pathogenesis.

  16. Electrodeposition and characterization of undoped and nitrogen-doped ZnSe films

    Energy Technology Data Exchange (ETDEWEB)

    Manzoli, A., E-mail: alexandra@cnpdia.embrapa.br [Institute of Chemistry of Sao Carlos (IQSC) - University of Sao Paulo (USP), P. O. Box 780, 13560-970, Sao Carlos, SP (Brazil); National Nanotechnology Laboratory for Agribusiness (LNNA), Embrapa Agricultural Instrumentation, P. O. Box 741, 13560-970, Sao Carlos, SP (Brazil); Eguiluz, K.I.B.; Salazar-Banda, G.R. [Institute of Chemistry of Sao Carlos (IQSC) - University of Sao Paulo (USP), P. O. Box 780, 13560-970, Sao Carlos, SP (Brazil); Institute of Technology and Research/University of Tiradentes, Av. Murilo Dantas, 300, 49032-490, Aracaju, SE (Brazil); Machado, S.A.S. [Institute of Chemistry of Sao Carlos (IQSC) - University of Sao Paulo (USP), P. O. Box 780, 13560-970, Sao Carlos, SP (Brazil)

    2010-05-15

    Semiconducting films of (n-type) ZnSe and (p-type) nitrogen-doped ZnSe were electrodeposited by a linear-sweep voltammetric technique on to a substrate of fluorine-tin oxide (FTO) glass ceramics. The films were characterized by scanning electron microscopy, energy-dispersive X-ray analysis and grazing-incidence X-ray diffraction. The results indicated that the material was deposited uniformly over the substrate, forming clusters when the Zn content of the bath was 0.1 mol L{sup -1} and a film when it was 0.2 or 0.3 mol L{sup -1}. The effectiveness of doping the films with nitrogen by adding ammonium sulfate to the deposition solution was assessed by measuring the film-electrolyte interface capacitance (C) at various applied potentials (E{sub ap}) and plotting Mott-Schottky curves (C{sup -2} vs E{sub ap}), whose slope sign was used to identify p-type ZnSe.

  17. Secondary structure and zinc ligation of human recombinant short-form stromelysin by multidimensional heteronuclear NMR.

    Science.gov (United States)

    Gooley, P R; Johnson, B A; Marcy, A I; Cuca, G C; Salowe, S P; Hagmann, W K; Esser, C K; Springer, J P

    1993-12-07

    Stromelysin-1, a member of the matrix metalloendoprotease family, is a zinc protease involved in the degradation of connective tissue in the extracellular matrix. As a step toward determining the structure of this protein, multidimensional heteronuclear NMR experiments have been applied to an inhibited truncated form of human stromelysin-1. Extensive 1H, 13C, and 15N sequential assignments have been obtained with a combination of three- and four-dimensional experiments. On the basis of sequential and short-range NOEs and 13C alpha chemical shifts, two helices have been delineated, spanning residues Asp-111 to Val-127 and Leu-195 to Ser-206. A third helix spanning residues Asp-238 to Gly-247 is characterized by sequential NOEs and 13C alpha chemical shifts, but not short-range NOEs. The lack of the latter NOEs suggests that this helix is either distorted or mobile. Similarly, sequential and interstrand NOEs and 13C alpha chemical shifts characterize a four-stranded beta-sheet with three parallel strands (Arg-100 to Ile-101, Ile-142 to Ala-147, Asp-177 to Asp-181) and one antiparallel strand (Ala-165 to Tyr-168). Two zinc sites have been identified in stromelysin [Salowe et al. (1992) Biochemistry 31, 4535-4540]. The NMR spectral properties, including chemical shift, pH dependence, and proton coupling of the imidazole nitrogens of six histidine residues (151, 166, 179, 201, 205, and 211), invariant in the matrix metalloendoprotease family, suggest that these residues are zinc ligands. NOE data indicate that these histidines form two clusters: one ligates the catalytic zinc (His-201, -205, and -211), and the other ligates a structural zinc (His-151, -166, and -179). Heteronuclear multiple quantum correlated spectra and specific labeling experiments indicate His-151, -179, -201, -205, and -211 are in the N delta 1H tautomer and His-166 is in the N epsilon 2H tautomer.

  18. Preparation and characterization of visible-light-active nitrogen-doped TiO2 photocatalyst

    Institute of Scientific and Technical Information of China (English)

    HUANG Xian-huai; TANG Yu-chao; HU Chun; YU Han-qing; CHEN Chu-sheng

    2005-01-01

    A visible-light photocatalyst was prepared by calcination of the hydrolysis product of Ti(SO4 )2 with ammonia as precipitator. The color of this photocatalyst was vivid yellow. It could absorb light under 550 nm wavelength. The crystal structure of anatase was characterized by XRD. The structure analysis result of X-ray fluorescence(XRF) shows that doped-nitrogen was presented in the sample.The photocatalytic activities were evaluated using methyl orange and phenol as model pollutants. The photocatalytic activities of samples were increasing gradually with calcination temperature from 400℃ to 700℃ under UV irradiation. It can be seen that the degradation of methyl orange follows zero-order kinetics. However, the calcination temperatures have no significant influence on the degradation of phenol under sunlight. The N-doped catalyst shows higher activity than the bare one under solar irradiation.

  19. Determinants of tubal ligation in Puebla, Mexico.

    Science.gov (United States)

    Rudzik, Alanna E F; Leonard, Susan H; Sievert, Lynnette L

    2011-06-21

    Tubal ligation provides an effective and reliable method by which women can choose to limit the number of children they will bear. However, because of the irreversibility of the procedure and other potential disadvantages, it is important to understand factors associated with women's choice of this method of birth control. Between May 1999 and August 2000, data were collected from 755 women aged 40 to 60 years from a cross-section of neighborhoods of varying socio-economic make-up in Puebla, Mexico, finding a tubal ligation rate of 42.2%. Multiple logistic regression models were utilized to examine demographic, socio-economic, and reproductive history characteristics in relation to women's choice of tubal ligation. Regression analyses were repeated with participants grouped by age to determine how the timing of availability of tubal ligation related to the decision to undergo the procedure. The results of this study suggest that younger age, more education, use of some forms of birth control, and increased parity were associated with women's decisions to undergo tubal ligation. The statistically significant difference of greater tubal ligation and lower hysterectomy rates across age groups reflect increased access to tubal ligation in Mexico from the early 1970s, supporting the idea that women's choice of tubal ligation was related to access.

  20. Preliminary characterization of nitrogen and phosphorus in groundwater discharging to Lake Spokane, northeastern Washington, using stable nitrogen isotopes

    Science.gov (United States)

    Gendaszek, Andrew S.; Cox, Stephen E.; Spanjer, Andrew R.

    2016-02-29

    Lake Spokane, locally referred to as Long Lake, is a 24-mile-long section of the Spokane River impounded by Long Lake Dam that has, in recent decades, experienced water-quality problems associated with eutrophication. Consumption of oxygen by the decomposition of aquatic plants that have proliferated because of high nutrient concentrations has led to seasonally low dissolved oxygen concentrations in the lake. Of nitrogen and phosphorus, the two primary nutrients necessary for aquatic vegetation growth, phosphorus was previously identified as the limiting nutrient that regulates the growth of aquatic plants and, thus, dissolved oxygen concentrations in Lake Spokane. Phosphorus is delivered to Lake Spokane from municipal and industrial point-source inputs to the Spokane River upstream of Lake Spokane, but is also conveyed by groundwater and surface water from nonpoint-sources including septic tanks, agricultural fields, and wildlife. In response, the Washington State Department of Ecology listed Lake Spokane on the 303(d) list of impaired water bodies for low dissolved oxygen concentrations and developed a Total Maximum Daily Load for phosphorus in 1992, which was revised in 2010 because of continuing algal blooms and water-quality concerns.This report evaluates the concentrations of phosphorus and nitrogen in shallow groundwater discharging to Lake Spokane to determine if a difference exists between nutrient concentrations in groundwater discharging to the lake downgradient of residential development with on-site septic systems and downgradient of undeveloped land without on-site septic systems. Elevated nitrogen isotope values (δ15N) within the roots of aquatic vegetation were used as an indicator of septic-system derived nitrogen. δ15N values were measured in August and September 2014 downgradient of residential development near the lakeshore, of residential development on 300-ft-high terraces above the lake, and of undeveloped land in the eastern (upper) and

  1. Melanin from the nitrogen-fixing bacterium Azotobacter chroococcum: a spectroscopic characterization.

    Directory of Open Access Journals (Sweden)

    Aulie Banerjee

    Full Text Available Melanins, the ubiquitous hetero-polymer pigments found widely dispersed among various life forms, are usually dark brown/black in colour. Although melanins have variety of biological functions, including protection against ultraviolet radiation of sunlight and are used in medicine, cosmetics, extraction of melanin from the animal and plant kingdoms is not an easy task. Using complementary physicochemical techniques (i.e. MALDI-TOF, FTIR absorption and cross-polarization magic angle spinning solid-state (13C NMR, we report here the characterization of melanins extracted from the nitrogen-fixing non-virulent bacterium Azotobacter chroococcum, a safe viable source. Moreover, considering dihydroxyindole moiety as the main constituent, an effort is made to propose the putative molecular structure of the melanin hetero-polymer extracted from the bacterium. Characterization of the melanin obtained from Azotobacter chroococcum would provide an inspiration in extending research activities on these hetero-polymers and their use as protective agent against UV radiation.

  2. Synthesis and characterization of well-aligned carbon nitrogen nanotubes by microwave plasma chemical vapor deposition

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Well-aligned carbon nitrogen nanotube films have been synthesized successfully on mesoporous silica substrates by microwave plasma chemical vapor deposition (MWPCVD) method. Studies on their morphology, structure, and composition by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy (EDX), respectively, indicate that these nanotubes consist of linearly polymerized carbon nitrogen nanobells, and the nitrogen atoms have been doped into carbon netweork to form a new structure C1-xNx (x=0.16±0.01). X-ray photoelectron spectroscopy (XPS) results of the samples further demonstrate that carbon bonds covalently with nitrogen in all the carbon nitrogen nanotube films.

  3. Bias in ligation-based small RNA sequencing library construction is determined by adaptor and RNA structure.

    Directory of Open Access Journals (Sweden)

    Ryan T Fuchs

    Full Text Available High-throughput sequencing (HTS has become a powerful tool for the detection of and sequence characterization of microRNAs (miRNA and other small RNAs (sRNA. Unfortunately, the use of HTS data to determine the relative quantity of different miRNAs in a sample has been shown to be inconsistent with quantitative PCR and Northern Blot results. Several recent studies have concluded that the major contributor to this inconsistency is bias introduced during the construction of sRNA libraries for HTS and that the bias is primarily derived from the adaptor ligation steps, specifically where single stranded adaptors are sequentially ligated to the 3' and 5'-end of sRNAs using T4 RNA ligases. In this study we investigated the effects of ligation bias by using a pool of randomized ligation substrates, defined mixtures of miRNA sequences and several combinations of adaptors in HTS library construction. We show that like the 3' adaptor ligation step, the 5' adaptor ligation is also biased, not because of primary sequence, but instead due to secondary structures of the two ligation substrates. We find that multiple secondary structural factors influence final representation in HTS results. Our results provide insight about the nature of ligation bias and allowed us to design adaptors that reduce ligation bias and produce HTS results that more accurately reflect the actual concentrations of miRNAs in the defined starting material.

  4. Ligation Bias in Illumina Next-Generation DNA Libraries

    DEFF Research Database (Denmark)

    Seguin-Orlando, Andaine; Schubert, Mikkel; Clary, Joel

    2013-01-01

    Ancient DNA extracts consist of a mixture of endogenous molecules and contaminant DNA templates, often originating from environmental microbes. These two populations of templates exhibit different chemical characteristics, with the former showing depurination and cytosine deamination by......-products, resulting from post-mortem DNA damage. Such chemical modifications can interfere with the molecular tools used for building second-generation DNA libraries, and limit our ability to fully characterize the true complexity of ancient DNA extracts. In this study, we first use fresh DNA extracts to demonstrate...... that library preparation based on adapter ligation at AT-overhangs are biased against DNA templates starting with thymine residues, contrarily to blunt-end adapter ligation. We observe the same bias on fresh DNA extracts sheared on Bioruptor, Covaris and nebulizers. This contradicts previous reports suggesting...

  5. Cloning of DNA fragments: ligation reactions in agarose gel.

    Science.gov (United States)

    Furtado, Agnelo

    2014-01-01

    Ligation reactions to ligate a desired DNA fragment into a vector can be challenging to beginners and especially if the amount of the insert is limiting. Although additives known as crowding agents, such as PEG 8000, added to the ligation mixes can increase the success one has with ligation reactions, in practice the amount of insert used in the ligation can determine the success or the failure of the ligation reaction. The method described here, which uses insert DNA in gel slice added directly into the ligation reaction, has two benefits: (a) using agarose as the crowding agent and (b) reducing steps of insert purification. The use of rapid ligation buffer and incubation of the ligation reaction at room temperature greatly increase the efficiency of the ligation reaction even for blunt-ended ligation.

  6. Characterizing the transformation and transfer of nitrogen during the aerobic treatment of organic wastes and digestates

    Energy Technology Data Exchange (ETDEWEB)

    Zeng Yang, E-mail: yang.zeng@irstea.fr [Irstea, UR GERE, 17 avenue de Cucille, CS 64427, F-35044 Rennes Cedex (France); Universite Europeenne de Bretagne, F-35000 Rennes (France); Guardia, Amaury de; Daumoin, Mylene; Benoist, Jean-Claude [Irstea, UR GERE, 17 avenue de Cucille, CS 64427, F-35044 Rennes Cedex (France)

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer Ammonia emissions varied depending on the nature of wastes and the treatment conditions. Black-Right-Pointing-Pointer Nitrogen losses resulted from ammonia emissions and nitrification-denitrification. Black-Right-Pointing-Pointer Ammonification can be estimated from biodegradable carbon and carbon/nitrogen ratio. Black-Right-Pointing-Pointer Ammonification was the main process contributing to N losses. Black-Right-Pointing-Pointer Nitrification rate was negatively correlated to stripping rate of ammonia nitrogen. - Abstract: The transformation and transfer of nitrogen during the aerobic treatment of seven wastes were studied in ventilated air-tight 10-L reactors at 35 Degree-Sign C. Studied wastes included distinct types of organic wastes and their digestates. Ammonia emissions varied depending on the kind of waste and treatment conditions. These emissions accounted for 2-43% of the initial nitrogen. Total nitrogen losses, which resulted mainly from ammonia emissions and nitrification-denitrification, accounted for 1-76% of the initial nitrogen. Ammonification was the main process responsible for nitrogen losses. An equation which allows estimating the ammonification flow of each type of waste according to its biodegradable carbon and carbon/nitrogen ratio was proposed. As a consequence of the lower contribution of storage and leachate rates, stripping and nitrification rates of ammonia nitrogen were negatively correlated. This observation suggests the possibility of promotingnitrification in order to reduce ammonia emissions.

  7. Orchidopexy san ligation technique of orchidopexy

    Directory of Open Access Journals (Sweden)

    Jain Vishal

    2011-01-01

    Full Text Available Pediatric hernia surgery is the most common operation done by pediatric general surgeons and it is a core competency for general surgeons in the developing world. Herniotomy is performed for the surgical repair of hernia and along with orchiopexy for the closure of associated patent processus vaginalis. Traditionally, ligation of hernial sac during orchiopexy is considered mandatory to prevent postoperative development of hernia. The present report was designed to study the results of non-ligation of the hernial sac during orchiopexy. It was found that non-ligation has no untoward effect on early complications and recurrence rate on long-term follow-up. It is suggested that it is not necessary to ligate the hernial sac during orchiopexy in children.

  8. Characterization of nitrogen-rich biomaterial-derived biochars and their sorption for aromatic compounds.

    Science.gov (United States)

    Zhang, Meng; Shu, Liang; Shen, Xiaofang; Guo, Xiaoying; Tao, Shu; Xing, Baoshan; Wang, Xilong

    2014-12-01

    Biochars from nitrogen-rich biomaterials (i.e., α-amylase, chitin and zein) were produced at different temperatures (i.e. 170, 250, 350 and 450 °C) and characterized, and their sorption for phenanthrene, naphthalene and 1-naphthol was investigated. The organic carbon content normalized-sorption coefficient (Koc) of the tested compounds by biochars increased with increasing charring temperature, attributed to the reduction of O-containing polar moieties especially the O-alkyl components, and the newly created aromatic carbon domains. The N-heterocyclic ring structure formed during charring process may enhance π-π interactions between aromatics and the aromatic components in the resulting biochars. However, π-π interactions did not dominate sorption of aromatics by N-rich biochars. Sorption of the tested compounds by N-rich biochars was predominantly controlled by the hydrophobic interactions between these chemicals and the aromatic components in biochars. Both N- and O-containing polar moieties at the biochar surfaces negatively affected their sorption for aromatics.

  9. Nitrogen-15 NMR characterization of the neutral form of 7-methylguanosine

    Energy Technology Data Exchange (ETDEWEB)

    Barbarella, G. (CNR, Bologna (Italy)); Bertoluzza, A.; Tugnoli, V. (Sezione di Chimica e Propedeutica Biochimica, Bologna (Italy))

    1988-07-25

    The commercial 7-methylguanosine used for several physico-chemical studies, and prepared by methylation of the parent guanosine, is a mixture of the neutral and the protonated forms, as shown by carbon-13 and nitrogen-15 NMR. Nitrogen-15 chemical shifts of the neutral and the protonated forms of 7-methylguanosine are shown.

  10. Synthesis and characterization of well-aligned carbon nitrogen nanotubes by microwave plasma chemical vapor deposition

    Institute of Scientific and Technical Information of China (English)

    马旭村; 徐贵昌; 王恩哥

    2000-01-01

    Well-aligned carbon nitrogen nanotube films have been synthesized successfully on meso-porous silica substrates by microwave plasma chemical vapor deposition (MWPCVD) method. Studies on their morphology, structure, and composition by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive X-ray spectroscopy (EDX), respectively, indicate that these nanotubes consist of linearly polymerized carbon nitrogen nanobells, and the nitrogen atoms have been doped into carbon netweork to form a new structure C1-xNx( x = 0.16±0.01). X-ray photoelectron spectroscopy (XPS) results of the samples further demonstrate that carbon bonds cova-lently with nitrogen in all the carbon nitrogen nanotube films.

  11. Blood flow changes after unilateral carotid artery ligation monitored by optical coherence tomography

    Science.gov (United States)

    Ma, Yushu; Liang, Chengbo; Suo, Yanyan; Zhao, Yuqian; Wang, Yi; Xu, Tao; Wang, Ruikang; Ma, Zhenhe

    2016-03-01

    Unilateral carotid artery ligation which could induce adaptive improvement is a classic model that has been widely used to study pathology of ischemic disease. In those studies, blood flow is an important parameter to characterize the ischemia. Optical coherence tomography (OCT) is a powerful imaging modality which can provide depth resolved images in biological tissue with high spatial and temporal resolution. SPF rats was anesthetized with isoflurane and divided into two groups. In first group, bilateral carotid artery was surgically exposed, and then left carotid artery was ligated. Blood flow changes of the contralateral carotid artery was monitored using high speed spectral domain optical coherence tomography, including the absolute flow velocity and the flow volume. In the other group, skull window was opened at the ipsilateral cerebral cortex of ligation and blood supply of small artery was measured before and after the ligation. The measured results demonstrate the blood supply compensation process after unilateral carotid artery ligation. With the superiority of high resolution, OCT is an effective technology in monitoring results of carotid artery after ligation.

  12. Ligation reaction specificities of an NAD(+)-dependent DNA ligase from the hyperthermophile Aquifex aeolicus.

    Science.gov (United States)

    Tong, J; Barany, F; Cao, W

    2000-03-15

    An NAD(+)-dependent DNA ligase from the hyperthermophilic bacterium Aquifex aeolicus was cloned, expressed in Escherichia coli and purified to homogeneity. The enzyme is most active in slightly alkaline pH conditions with either Mg(2+)or Mn(2+)as the metal cofactor. Ca(2+)and Ni(2+)mainly support formation of DNA-adenylate intermediates. The catalytic cycle is characterized by a low k (cat)value of 2 min(-1)with concomitant accumulation of the DNA - adenylate intermediate when Mg(2+)is used as the metal cofactor. The ligation rates of matched substrates vary by up to 4-fold, but exhibit a general trend of T/A ligation reaction is reaffirmed by results from 1 nt insertions on either the 3'- or 5'-side of the nick. Furthermore, most of the unligatable 3' mismatched base pairs prohibit formation of the DNA-adenylate intermediate, indicating that the substrate adenylation step is also a control point for ligation fidelity. Unlike previously studied ATP ligases, gapped substrates cannot be ligated and intermediate accumulation is minimal, suggesting that complete elimination of base pair complementarity on one side of the nick affects substrate adenylation on the 5'-side of the nick junction. Relationships among metal cofactors, ligation products and intermediate, and ligation fidelity are discussed.

  13. Hypermutable ligation of plasmid DNA ends in cells from patients with Werner syndrome.

    Science.gov (United States)

    Rünger, T M; Bauer, C; Dekant, B; Möller, K; Sobotta, P; Czerny, C; Poot, M; Martin, G M

    1994-01-01

    Werner Syndrome is a rare autosomal recessive disorder characterized by an increased cancer risk and by symptoms suggestive of premature aging. Cells from these patients demonstrate a typical pattern of chromosomal instability and a spontaneous hypermutability with a high rate of unusually large deletions. We have studied the in vivo DNA ligation in three lymphoblast cell lines from Werner syndrome patients and three from normal donors. In our host cell ligation assay we transfected linearized plasmid pZ189 and measured the amount of plasmid DNA ends rejoined by these host cells as the ability of the recovered plasmid to transform bacteria. A mutagenesis marker gene close to the ligation site allowed screening for mutations. Subsequent mutation analysis provided information about the accuracy of the ligation process. The cells from Werner syndrome patients were as effective as normal cells in ligating DNA ends. However, mutation analysis revealed that the three Werner syndrome cell lines introduced 2.4-4.6 times more mutations (p < 0.001) than the normal cell lines during ligation of the DNA ends: the mutation rates were 69.4, 97.2, and 58.7%, as compared to 23.6, 21.7, and 24.4% in the normal cell lines. These increased mutation frequencies in plasmids ligated during passage through Werner syndrome cells were mainly due to a significant (p < 0.001) increase in deletions. This error-prone DNA ligation might be responsible for the spontaneous hypermutability and the genomic instability in Werner syndrome cells and related to the apparently accelerated aging and high cancer risk in affected patients.

  14. Combining ligation reaction and capillary gel electrophoresis to obtain reliable long DNA probes.

    Science.gov (United States)

    García-Cañas, Virginia; Mondello, Monica; Cifuentes, Alejandro

    2011-05-01

    New DNA amplification methods are continuously developed for sensitive detection and quantification of specific DNA target sequences for, e.g. clinical, environmental or food applications. These new applications often require the use of long DNA oligonucleotides as probes for target sequences hybridization. Depending on the molecular technique, the length of DNA probes ranges from 40 to 450 nucleotides, solid-phase chemical synthesis being the strategy generally used for their production. However, the fidelity of chemical synthesis of DNA decreases for larger DNA probes. Defects in the oligonucleotide sequence result in the loss of hybridization efficiency, affecting the sensitivity and selectivity of the amplification method. In this work, an enzymatic procedure has been developed as an alternative to solid-phase chemical synthesis for the production of long oligonucleotides. The enzymatic procedure for probe production was based on ligation of short DNA sequences. Long DNA probes were obtained from smaller oligonucleotides together with a short sequence that acts as bridge stabilizing the molecular complex for DNA ligation. The ligation reactions were monitored by capillary gel electrophoresis with laser-induced fluorescence detection (CGE-LIF) using a bare fused-silica capillary. The capillary gel electrophoresis-LIF method demonstrated to be very useful and informative for the characterization of the ligation reaction, providing important information about the nature of some impurities, as well as for the fine optimization of the ligation conditions (i.e. ligation cycles, oligonucleotide and enzyme concentration). As a result, the yield and quality of the ligation product were highly improved. The in-lab prepared DNA probes were used in a novel multiplex ligation-dependent genome amplification (MLGA) method for the detection of genetically modified maize in samples. The great possibilities of the whole approach were demonstrated by the specific and sensitive

  15. Synthesis and characterization of a single diamond crystal with a high nitrogen concentration

    Institute of Scientific and Technical Information of China (English)

    Zhang Zhuang-Fei; Jia Xiao-Peng; Liu Xiao-Bing; Hu Mei-Hua; Li Yong; Yan Bing-Min; Ma Hong-An

    2012-01-01

    In this paper,we explore diamond synthesis with a series of experiments using an Fe-Ni catalyst and a P3N5 additive in the temperature range of 1250-1550 ℃ and the pressure range of 5.0-6.3 GPa.We also investigate the influence of nitrogen on diamond crystallization. Our results show that the synthesis conditions (temperature and pressure) increase with the amount of P3N5 additive increasing.The nitrogen impurity can significantly influence the diamond morphology.The diamonds stably grow into strip and lamellar shapes in the nitrogen-rich environment.The Fourier-transform infrared spectrum shows that the nitrogen concentration increases rapidly with the content of P3N5 additive increasing.By spectrum analysis,we find that with the increase of the nitrogen concentration,the Ib-type nitrogen atoms can aggregate in the A-centre form. The highest A-centre nitrogen concentration is approximately 840 ppm.

  16. Synthesis and Characterization of Mesoporous Silicon Oxynitride MCM-41 with High Nitrogen Content

    Institute of Scientific and Technical Information of China (English)

    ZHANG Cunman; XU Zheng; LIU Qian

    2005-01-01

    Mesoporous silicon oxynitrides MCM-41 were synthesized successfully. The resulting materials not only have high nitrogen contents and good structural characteristics of MCM-41 (high surface area, narrow pore size distribution and good order), but also are amorphous. The composition and structure of the materials were investigated by CNH element analysis, XPS, Si MAS NMR, XRD, HRTEM and N2 sorption, respectively. Mesoporous silicon oxynitrides MCM-41 with a high nitrogen content are still non-crystal (amorphous).

  17. Post-functionalization of polymers via orthogonal ligation chemistry.

    Science.gov (United States)

    Goldmann, Anja S; Glassner, Mathias; Inglis, Andrew J; Barner-Kowollik, Christopher

    2013-05-27

    The establishment of advanced living/controlled polymerization protocols allows for engineering synthetic polymers in a precise fashion. Combining advanced living/controlled polymerization techniques with highly efficient coupling chemistries facilitates quantitative, modular, and orthogonal functionalization of synthetic polymer strands at their chain termini as well as side-chain functionalization. The review highlights the current status of selected post-functionalization techniques of polymers via orthogonal ligation chemistries, major characteristics of the specific transformation chemistry, as well as the characterization of the products.

  18. Synergetic inhibition of thermochemical formation of chlorinated aromatics by sulfur and nitrogen derived from thiourea: Multielement characterizations.

    Science.gov (United States)

    Fujimori, Takashi; Nakamura, Madoka; Takaoka, Masaki; Shiota, Kenji; Kitajima, Yoshinori

    2016-07-01

    Nitrogen and sulfur (N/S)-containing compounds inhibit the formation of polychlorinated dibenzo-p-dioxins (PCDDs) and furans (PCDFs) in thermal processes. However, few studies have examined the inhibition mechanisms of N/S-containing compounds. In the present study, we focused on thiourea [(NH2)2CS] as such a compound and investigated its inhibition effects and mechanisms. The production of PCDD/Fs, polychlorinated biphenyls (PCBs), and chlorobenzenes (CBzs) were inhibited by >99% in the model fly ash in the presence of 1.0% thiourea after heating at 300 °C. Experimental results using real fly ash series were indicative of the thermal destruction of these chlorinated aromatics by thiourea. Multielement characterization using K-edge X-ray absorption fine structures of copper, chlorine, sulfur, nitrogen, and carbon revealed three possible inhibition paths, namely, (a) sulfidization of the copper catalyst to CuS, Cu2S, and CuSO4; (b) blocking the chlorination of carbon via the reaction of chlorine with N-containing compounds to generate ammonium chloride and other minor compounds; and (c) changing the carbon frame involved in attacking the carbon matrix by sulfur and nitrogen. Thus, thiourea plays a role as a sulfur and nitrogen donor to achieve multiple and synergistic inhibition of chlorinated aromatics. Our results suggest that other N/S-containing inhibitors function based on similar mechanisms.

  19. Torque expression in self-ligating orthodontic brackets and conventionally ligated brackets: A systematic review

    Science.gov (United States)

    Al-Thomali, Yousef; Mohamed, Roshan-Noor; Basha, Sakeenabi

    2017-01-01

    Background To evaluate the torque expression of self ligating (SL) orthodontic brackets and conventionally ligated brackets and the torque expression in active and passive SL brackets. Material and Methods Our systematic search included MEDLINE, EMBASE, CINAHL, PsychINFO, Scopus, and key journals and review articles; the date of the last search was April 4th 2016. We graded the methodological quality of the studies by means of the Quality Assessment Tool for Quantitative Studies, developed for the Effective Public Health Practice Project (EPHPP). Results In total, 87 studies were identified for screening, and 9 studies were eligible. The quality assessment rated one of the study as being of strong quality, 7 (77.78%) of these studies as being of moderate quality. Three out of 7 studies which compared SL and conventionally ligated brackets showed, conventionally ligated brackets with highest torque expression compared to SL brackets. Badawi showed active SL brackets with highest torque expression compared to passive SL brackets. Major and Brauchli showed no significant differences in torque expression of active and passive SL brackets. Conclusions Conventionally ligated brackets presented with highest torque expression compared to SL brackets. Minor difference was recorded in a torque expression of active and passive SL brackets. Key words:Systematic review, self ligation, torque expression, conventional ligation. PMID:28149476

  20. Ligation of double-stranded and single-stranded [Oligo(dT)] DNA by vaccinia virus DNA ligase

    OpenAIRE

    1996-01-01

    Vaccinia virus DNA ligase has been expressed in Escherichia coli, purified, and biochemically characterized. The enzyme ligates double-stranded (ds) DNA substrates with either cohesive or blunt-end termini and the latter reaction is stimulated by PEG. Vaccinia virus DNA ligase can also ligate oligo(dT) when annealed to either a poly(dA) or a poly(rA) backbone and, remarkably, free oligo(dT). This ligation of a single-stranded (ss) substrate is unique among eukaryotic DNA ligases. The enzyme r...

  1. Preparation, characterization and visible light photocatalytic activity of silver, nitrogen co-doped TiO2 photocatalyst

    Science.gov (United States)

    Khan, Matiullah; Ramin Gul, Sahar; Li, Jing; Cao, Wenbin; Mamalis, Athanasios G.

    2015-06-01

    TiO2 photocatalyst codoped with Silver (Ag) and Nitrogen (N) with different Ag doping concentrations is successfully synthesized by hydrothermal method. The as-synthesized samples are characterized through x-ray diffraction (XRD), Transmission electron microscopy (TEM), UV-vis. absorption spectra and x-ray photoelectron spectroscopy (XPS). The photocatalytic response is evaluated by the photodegradation of methylene blue under visible light irradiations. All synthesized samples are composed of pure anatase phase with good crystallinity. The absorption edge of codoped TiO2 is shifted towards visible light region. X-ray photoelectron spectroscopy confirmed the existence of silver and nitrogen in the codoped samples. All the codoped samples demonstrated improved photocatalytic activity compared to pure TiO2. Among the different codoped samples, the one with silver doping concentration of 4 at. % exhibited the highest photoactivity.

  2. Carbon/nitrogen-doped TiO2: New synthesis route, characterization and application for phenol degradation

    Directory of Open Access Journals (Sweden)

    Aboubakr M. Abdullah

    2016-03-01

    Full Text Available Porous nanocrystalline carbon and nitrogen (CN-doped TiO2 photocatalyst was prepared using carbon tetrachloride and polyaniline as precursors. The obtained powders were characterized by X-ray diffraction (XRD, X-ray photoelectron spectroscopy (XPS, scanning electron microscopy (SEM, Raman spectroscopy, Fourier transform infrared (FT-IR spectroscopy, and gravimetric analysis. The purpose of this work was to explore the state and location of nitrogen and carbon atoms introduced inside the TiO2 lattice and to study the exploitation of the photocatalytic activity of the CN-doped TiO2 for application in phenol degradation under UV illumination. After 30 min from the illumination onset, 64% and 57% of the phenol were degraded when the CN-doped TiO2 and TiO2 catalysts were used respectively.

  3. Increasing the efficiency of SAGE adaptor ligation by directed ligation chemistry

    Science.gov (United States)

    So, Austin P.; Turner, Robin F. B.; Haynes, Charles A.

    2004-01-01

    The ability of Serial Analysis of Gene Expression (SAGE) to provide a quantitative picture of global gene expression relies not only on the depth and accuracy of sequencing into the SAGE library, but also on the efficiency of each step required to generate the SAGE library from the starting mRNA material. The first critical step is the ligation of adaptors containing a Type IIS recognition sequence to the anchored 3′ end cDNA population that permits the release of short sequence tags (SSTs) from defined sites within the 3′ end of each transcript. Using an in vitro transcript as a template, we observed that only a small fraction of anchored 3′ end cDNA are successfully ligated with added SAGE adaptors under typical reaction conditions currently used in the SAGE protocol. Although the introduction of ∼500-fold molar excess of adaptor or the inclusion of 15% (w/v) PEG-8000 increased the yield of the adaptor-modified product, complete conversion to the desired adaptor:cDNA hetero-ligation product is not achieved. An alternative method of ligation, termed as directed ligation, is described which exploits a favourable mass-action condition created by the presence of NlaIII during ligation in combination with a novel SAGE adaptor containing a methylated base within the ligation site. Using this strategy, we were able to achieve near complete conversion of the anchored 3′ end cDNA into the desired adaptor-modified product. This new protocol therefore greatly increases the probability that a SST will be generated from every transcript, greatly enhancing the fidelity of SAGE. Directed ligation also provides a powerful means to achieve near-complete ligation of any appropriately designed adaptor to its respective target. PMID:15247329

  4. Characterization of nitrogen ion implanted TiO{sub 2} photocatalysts by XAFS and XPS

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Tomoko [EcoTopia Science Institute, Nagoya University, Nagoya 464-8603 (Japan); Niimi, Satoshi; Yamamoto, Muneaki; Ogawa, Satoshi [Graduate School of Engineering, Nagoya University, Nagoya 464-8603 (Japan); Nomoto, Toyokazu [Aichi Synchrotron Radiation Center, 250-3, Minamiyamaguchi-cho, Seto 489-0965 (Japan); Yagi, Shinya [EcoTopia Science Institute, Nagoya University, Nagoya 464-8603 (Japan)

    2015-12-15

    A nitrogen doped TiO{sub 2} as a visible-light response photocatalyst was prepared by N{sup +} implantation technique. N{sup +}-implanted TiO{sub 2} samples promoted the photocatalytic activity for degradation of methylene blue under visible-light irradiation. XANES and XPS analyses indicated two types of chemical state of nitrogen, one photo-catalytically active N substituting the O sites and the other inactive NOx (1 ⩽ x ⩽ 2) species. In the valence band XPS spectrum of the high activity sample, the additional electronic states were observed just above the valence band edge of a TiO{sub 2}. The electronic state would be originated from the substitutional nitrogen and be responsible for the band gap narrowing, i.e., visible light response of TiO{sub 2} photocatalysts.

  5. Synthesis, characterization and visible light photocatalytic activity of nitrogen-doped zinc oxide nanospheres

    OpenAIRE

    Atul B. Lavand; Yuvraj S. Malghe

    2015-01-01

    Pure and Nitrogen (N)-doped ZnO nanospheres were successfully prepared using microemulsion method. X-ray diffraction (XRD) study indicates formation of nanosized N-doped ZnO with wurtzite phase. Nitrogen incorporation into oxygen site of ZnO causes lattice compression and small peak shift toward lower 2θ value. Raman and Fourier transform infrared (FTIR) measurements revealed the presence of N in ZnO lattice. Scanning electron microscopy (FESEM) study revealed spherical morphology of pure and...

  6. Characterization of micro-mesoporous materials from nitrogen and toluene adsorption: experiment and modeling.

    Science.gov (United States)

    Ravikovitch, Peter I; Vishnyakov, Aleksey; Neimark, Alexander V; Ribeiro Carrott, Manuela M L; Russo, Patrícia A; Carrott, Peter J

    2006-01-17

    Universal mechanisms of adsorption and capillary condensation of toluene and nitrogen on ordered MCM-41 and PHTS materials are studied by means of high-resolution experiments and Monte Carlo molecular simulations. A molecular simulation model of toluene adsorption in silica nanopores, which accounts for surface heterogeneity, and a hybrid molecular-macsroscopic method for pore size distribution (PSD) calculations have been developed. For a range of reference materials, the PSD results obtained from toluene isotherms are consistent with the results of nitrogen adsorption using the nonlocal density functional theory method.

  7. Characterization of an atmospheric double arc argon-nitrogen plasma source

    Science.gov (United States)

    Tu, X.; Chéron, B. G.; Yan, J. H.; Yu, L.; Cen, K. F.

    2008-05-01

    In the framework of studies devoted to hazardous waste destruction, an original dc double anode plasma torch has been designed and tested, which produces an elongated, weak fluctuation and reproducible plasma jet at atmospheric pressure. The arc instabilities and dynamic behavior of the double arc argon-nitrogen plasma jet are investigated through the oscillations of electrical signals by combined means of fast Fourier transform and Wigner distribution. In our experiment, the restrike mode is identified as the typical fluctuation behavior in an argon-nitrogen plasma jet. The Fourier spectra and Wigner distributions exhibit two characteristic frequencies of 150 Hz and 4.1 kHz, which reveals that the nature of fluctuations in the double arc argon-nitrogen plasma can be ascribed to the undulation of the power supply and both arc roots motion on the anode channels. In addition, the microscopic properties of the plasma jet inside and outside the arc chamber are investigated by means of optical emission spectroscopy, which yields excitation, electronic, rotational, and vibrational temperatures, as well as the electron number density. The results allow us to examine the validity criteria of a local thermodynamic equilibrium (LTE) state in the plasma arc. The measured electron densities are in good agreement with those calculated from the LTE model, which indicates that the atmospheric double arc argon-nitrogen plasma in the core region is close to the LTE state under our experimental conditions.

  8. Post tubal ligation syndrome or iatrogenic hydrosalpinx.

    Science.gov (United States)

    Gregory, M G

    1981-10-01

    The purpose of this case report is as follows: to attempt to establish an association between the observed increase in hydrosalpinx and the phenomenal increase in surgical sterilization; to present a credible etiology for iatrogenic hydrosalpinx; and to discuss the pathogenesis of a disease process henceforth referred to as post tubal ligation syndrome. A 36-year-old white woman was admitted to Park View Hospital in Nashville, Tennessee on January 7, 1981 for evaluation of continuous lower abdominal pain, abdominal pressure, and dyspareunia for several months. The woman had 2 children who were delivered vaginally. An abdominal tubal ligation was performed for sterilization when she was 27, and vaginal hysterectomy, with anterior and posterior colporrhaphy, was done for symptomatic pelvic relaxation at age 33. Physical examination showed tenderness without palpable masses in the pelvic adnexal areas. Laboratory studies were within normal limits. On January 9, 1981, the patient underwent exploratory laparotomy, and bilateral salpingo-oophorectomy. She was found to have bilateral hydrosalpinx. Historically, hydrosalpinx has been considered an intermediary step in pelvic inflammatory disease. Iatrogenic hydrosalpinx is, in essence, initiated by an initial insult, e.g., tubal ligation, fulguration, or application of a mechanical clip or band. Theoretically, single point interruption of a fallopian tube should produce no ill effects. The popularity and success of tubal ligation attest to single point interruption of an otherwise normal fallopian tube as an innocuous procedure. A schematic drawing is provided of the same tube insulted a 2nd time and consequently the situation is prefactory to development of hydrosalpinx, i.e., a tube lined with secretory epithelium is closed at both ends. Secretion within this closed system will produce dilatation. This "2nd" insult to the normal fallopian tube, post tubal ligation, may take 1 of several forms. The symptoms of iatrogenic

  9. A comparative study of Barron's rubber band ligation with Kshar Sutra ligation in hemorrhoids

    OpenAIRE

    2010-01-01

    Despite a long medical history of identification and treatment, hemorrhoids still pose a challenge to the medical fraternity in terms of finding satisfactory cure of the disease. In this study, Kshar Sutra Ligation (KSL), a modality of treatment described in Ayurveda, was compared with Barron's Rubber Band Ligation (RBL) for grade II and grade III hemorrhoids. This study was conducted in 20 adult patients of either sex with grade II and grade III hemorrhoids at two different hospitals. Patien...

  10. Synthesis, characterization and visible light photocatalytic activity of nitrogen-doped zinc oxide nanospheres

    Directory of Open Access Journals (Sweden)

    Atul B. Lavand

    2015-09-01

    Full Text Available Pure and Nitrogen (N-doped ZnO nanospheres were successfully prepared using microemulsion method. X-ray diffraction (XRD study indicates formation of nanosized N-doped ZnO with wurtzite phase. Nitrogen incorporation into oxygen site of ZnO causes lattice compression and small peak shift toward lower 2θ value. Raman and Fourier transform infrared (FTIR measurements revealed the presence of N in ZnO lattice. Scanning electron microscopy (FESEM study revealed spherical morphology of pure and N-doped ZnO samples. UV–visible spectra show that N-doping significantly enhanced the light absorption capacity of ZnO in the visible region. N-doped ZnO exhibits higher photocatalytic activity compared with that of commercial and pure ZnO nanoparticles. As prepared nanosized N-doped ZnO photocatalyst is highly stable and reusable.

  11. Characterization of humus microbial communities in adjacent forest types that differ in nitrogen availability.

    Science.gov (United States)

    Leckie, S E; Prescott, C E; Grayston, S J; Neufeld, J D; Mohn, W W

    2004-07-01

    To address the link between soil microbial community composition and soil processes, we investigated the microbial communities in forest floors of two forest types that differ substantially in nitrogen availability. Cedar-hemlock (CH) and hemlock-amabilis fir (HA) forests are both common on northern Vancouver Island, B.C., occurring adjacently across the landscape. CH forest floors have low nitrogen availability and HA high nitrogen availability. Total microbial biomass was assessed using chloroform fumigation-extraction and community composition was assessed using several cultivation-independent approaches: denaturing gradient gel electrophoresis (DGGE) of the bacterial communities, ribosomal intergenic spacer analysis (RISA) of the bacterial and fungal communities, and phospholipid fatty acid (PLFA) profiles of the whole microbial community. We did not detect differences in the bacterial communities of each forest type using DGGE and RISA, but differences in the fungal communities were detected using RISA. PLFA analysis detected subtle differences in overall composition of the microbial community between the forest types, as well as in particular groups of organisms. Fungal PLFAs were more abundant in the nitrogen-poor CH forests. Bacteria were proportionally more abundant in HA forests than CH in the lower humus layer, and Gram-positive bacteria were proportionally more abundant in HA forests irrespective of layer. Bacterial and fungal communities were distinct in the F, upper humus, and lower humus layers of the forest floor and total biomass decreased in deeper layers. These results indicate that there are distinct patterns in forest floor microbial community composition at the landscape scale, which may be important for understanding nutrient availability to forest vegetation.

  12. Identification and characterization of land use driven nitrogen fluxes using stable isotopes and reactive hydrologic modeling

    Science.gov (United States)

    Macko, S. A.; O'Connell, M. T.

    2015-12-01

    The Najinhe watershed is a topographically diverse, mixed agricultural and urban region in northeastern China that provides opportunities for identification of the impact of land use on nitrogen cycling. In addition to agricultural soil amendments, seasonal variation in atmospheric flow introduces dry and wet deposition from urban and desert sources. Both agricultural amendments and atmospheric sources are significant non-point inputs of reactive N, at estimated annual rates of 450 kg/ha and 30 kg/ha respectively in the nearby North China Plain.Both historic and current land use has influenced the biological processing of nitrogen in a particular area. Soil conditions, including moisture, texture, and organic content, control the capacity of a parcel for processing reactive nitrogen. Compounds derived from natural and anthropogenic sources exhibit characteristic stable isotopes of nitrogen and oxygen that serve as tracers of origin as well as integrators of biological processes. Analysis of bulk soils (including both organic and inorganic N contents) in the system shows δ15N ranging from 1.3 - 8.6 ‰ suggesting varying influence of anthropogenic inputs, fertilizers, soil organic nitrogen, and atmospheric sources based on land use.A distributed hydrologic model coupled with one focusing on reactive transport is able to help determine locations with the highest impact on the dissolved N in this system. Spatial statistical methods are employed to determine the biogeochemical influence of model locations whereas δ18O on soil NO3- and δ15N measurements on NO3- and NH4+ in surface water and soil extracts are used to calibrate and validate model predictions based on measured precipitation and streamflow values. Sources are integrated using a Bayesian mixing model to determine likely fate and transport parameters for various N inputs to the watershed. The application of the coupled hydrologic and transport models to a landscape scale catchment suggests integration and

  13. Development of hepatorenal syndrome in bile duct ligated rats

    Institute of Scientific and Technical Information of China (English)

    Regina M Pereira; Ana Cristina Sim(o)es e Silva; Robson AS dos Santos; Eduardo A Oliveira; Virg(i)nia HR Leite; Filipi LC Dias; Alysson S Rezende; Lincoln P Costa; Luciola S Barcelos; Mauro M Teixeira

    2008-01-01

    AIM: To evaluate in bile duct ligated rats whether there were progressive alterations of renal function without changes in histopathology.METHODS: Male Wistar rats were submitted to sham-surgery or bile duct ligation (BDL) and divided according to the post-procedure time (2, 4 and 6-wk).To determine renal function parameters, rats were placed in metabolic cages and, at the end of the experiment, blood and urine samples were obtained.Histology and hydroxyproline content were analyzed in liver and renal tissue.RESULTS: Rats with 2 wk of BDL increased free water clearance (P = 0.02), reduced urinary osmolality (P =0.03) and serum creatinine (P = 0.01) in comparison to the sham group. In contrast, rats at 6 wk of BDL showed features of HRS, including significant increase in serum creatinine and reductions in creatinine clearance,water excretion and urinary sodium concentration. Rats with 4 wk of BDL exhibited an intermediate stage of renal dysfunction. Progressive hepatic fibrosis according to post-procedure time was confirmed by histology.The increased levels of liver hydroxyproline contrasted with the absence of structural changes in the kidney, as assessed by histology and unchanged hydroxyproline content in renal tissue.CONCLUSION: Our data show that BDL produced progressive renal dysfunction without structural changes in the kidney, characterizing HRS. The present model will be useful to understand the pathophysiology of HRS.

  14. Molecular characterization of nitrogen and sulfur containing compounds in night-time SOA

    Science.gov (United States)

    Iinuma, Yoshiteru; Mutzel, Anke; Rodigast, Maria; Böge, Olaf; Herrmann, Hartmut

    2014-05-01

    The oxidation of volatile organic compounds (VOCs) leads to the formation of low volatile organic compounds that can form secondary organic aerosol (SOA). Studies in the past showed that laboratory generated and ambient SOA are made of polar molecules with O/C ratios generally greater than 0.5. More recent studies have shown that SOA compounds can contain heteroatoms mainly sulfur and nitrogen atoms. Offline chemical analysis with high-resolution mass spectrometers and fragmentation experiments has shown that sulphur containing compounds are mainly organosulfates and nitrogen containing species are aromatic heterocyclic compounds such as imidazole and nitrated aromatic compounds such as nitrophenols. In addition to these, SOA compounds containing both sulfur and nitrogen have been reported from the analysis of ambient organic aerosol, rainwater, fog and cloud samples. Based on the mass spectrometric evidence these compounds are attributed to nitrooxy-organosulfates originating from isoprene and monoterpenes. Although these compounds are ubiquitously detected in the ambient samples, reports about their detection in laboratory generated SOA are scares and their formation mechanisms are not well understood. In the present study, we investigated the formation of sulfur and nitrogen containing SOA species in the oxidation of biogenic VOCs. Photooxidation and night-time oxidation experiments were performed in a smog chamber to produce SOA samples. The laboratory generated SOA samples were analysed with UPLC-IMS-TOFMS (Ultra Performance Liquid Chromatography coupled to Ion Mobility Spectrometry and Time of Flight Mass Spectrometry). The presence of highly acidic sulphate seed particles (pH0) did not promote the formation of compounds with chemical formula of C10H17NO7S- and m/z value of 294.0653, indicating that the formation mechanisms of these compounds unlikely involve the ring opening reactions of epoxides and subsequent sulfation reactions. On the other hand, their

  15. Regulation of the nitrogen transfer pathway in the arbuscular mycorrhizal symbiosis: gene characterization and the coordination of expression with nitrogen flux.

    Science.gov (United States)

    Tian, Chunjie; Kasiborski, Beth; Koul, Raman; Lammers, Peter J; Bücking, Heike; Shachar-Hill, Yair

    2010-07-01

    The arbuscular mycorrhiza (AM) brings together the roots of over 80% of land plant species and fungi of the phylum Glomeromycota and greatly benefits plants through improved uptake of mineral nutrients. AM fungi can take up both nitrate and ammonium from the soil and transfer nitrogen (N) to host roots in nutritionally substantial quantities. The current model of N handling in the AM symbiosis includes the synthesis of arginine in the extraradical mycelium and the transfer of arginine to the intraradical mycelium, where it is broken down to release N for transfer to the host plant. To understand the mechanisms and regulation of N transfer from the fungus to the plant, 11 fungal genes putatively involved in the pathway were identified from Glomus intraradices, and for six of them the full-length coding sequence was functionally characterized by yeast complementation. Two glutamine synthetase isoforms were found to have different substrate affinities and expression patterns, suggesting different roles in N assimilation. The spatial and temporal expression of plant and fungal N metabolism genes were followed after nitrate was added to the extraradical mycelium under N-limited growth conditions using hairy root cultures. In parallel experiments with (15)N, the levels and labeling of free amino acids were measured to follow transport and metabolism. The gene expression pattern and profiling of metabolites involved in the N pathway support the idea that the rapid uptake, translocation, and transfer of N by the fungus successively trigger metabolic gene expression responses in the extraradical mycelium, intraradical mycelium, and host plant.

  16. Characterization of free nitrogen fixing bacteria of the genus Azotobacter in organic vegetable-grown Colombian soils

    Directory of Open Access Journals (Sweden)

    Diego Javier Jiménez

    2011-09-01

    Full Text Available With the purpose of isolating and characterizing free nitrogen fixing bacteria (FNFB of the genus Azotobacter, soil samples were collected randomly from different vegetable organic cultures with neutral pH in different zones of Boyacá-Colombia. Isolations were done in selective free nitrogen Ashby-Sucrose agar obtaining a recovery of 40%. Twenty four isolates were evaluated for colony and cellular morphology, pigment production and metabolic activities. Molecular characterization was carried out using amplified ribosomal DNA restriction analysis (ARDRA. After digestion of 16S rDNA Y1-Y3 PCR products (1487pb with AluI, HpaII and RsaI endonucleases, a polymorphism of 16% was obtained. Cluster analysis showed three main groups based on DNA fingerprints. Comparison between ribotypes generated by isolates and in silico restriction of 16S rDNA partial sequences with same restriction enzymes was done with Gen Workbench v.2.2.4 software. Nevertheless, Y1-Y2 PCR products were analysed using BLASTn. Isolate C5T from tomato (Lycopersicon esculentum grown soils presented the same in silico restriction patterns with A. chroococcum (AY353708 and 99% of similarity with the same sequence. Isolate C5CO from cauliflower (Brassica oleracea var. botrytis grown soils showed black pigmentation in Ashby-Benzoate agar and high similarity (91% with A. nigricans (AB175651 sequence. In this work we demonstrated the utility of molecular techniques and bioinformatics tools as a support to conventional techniques in characterization of the genus Azotobacter from vegetable-grown soils.

  17. Cost saving by reloading the multiband ligator in endoscopic esophageal variceal ligation: A proposal for developing countries

    Institute of Scientific and Technical Information of China (English)

    Zaigham Abbas; Lubna Rizvi; Umair Syed Ahmed; Khalid Mumtaz; Wasim Jafri

    2008-01-01

    AIM: To assess the cost savings of reloading the multiband ligator in endoscopic esophageal variceal ligation (EVL) used on the same patient for subsequent sessions,METHODS: This single centre retrospective descriptive study analysed patients undergoing variceal ligation at a tertiary care centre between 1st January, 2003 and 30th June, 2006. The multiband ligator was reloaded with six hemorrhoidal bands using hemorrhoidal ligator for the second and subsequent sessions. Analysis of cost saving was done for the number of follow-up sessions for the variceal eradication.RESULTS: A total of 261 patients underwent at least one session of endoscopic esophageal variceal ligation between January 2003 and June 2006. Out of 261, 108 patients (males 67) agreed to follow the eradication program and underwent repeated sessions. A total of 304 sessions was performed with 2.81 sessions per patient on average. Thirty-two patients could not complete the programm. In 76 patients (70%), variceal obliteration was achieved. The ratio of the costs for the session with reloaded ligator versus a session with a new ligator was 1:2.37. Among the patients who completed esophageal varices eradication, cost saving with reloaded ligator was 58%.CONCLUSION: EVL using reloaded multiband ligators for the follow-up sessions on patients undergoing variceal eradication is a cost saving procedure. Reloading the ligator thus is recommended especially for developing countries where most of the patients are not health insured.

  18. Structural characterization of buried nitride layers formed by nitrogen ion implantation in silicon

    Energy Technology Data Exchange (ETDEWEB)

    Yadav, A.D. [Department of Physics, University of Mumbai, Vidyanagari Campus, Santacruz (E), Mumbai, Maharashtra 400098 (India)], E-mail: adyadav@physics.mu.ac.in; Patel, A.P.; Dubey, S.K. [Department of Physics, University of Mumbai, Vidyanagari Campus, Santacruz (E), Mumbai, Maharashtra 400098 (India); Panigrahi, B.K.; Kesavamoorthy, R.; Nair, K.G.M. [Materials Science Division, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamilnadu 603102 (India)

    2008-04-15

    The synthesis of buried silicon nitride insulating layers was carried out by SIMNI (separation by implanted nitrogen) process using implantation of 140 keV nitrogen ({sup 14}N{sup +}) ions at fluence of 1.0 x 10{sup 17}, 2.5 x 10{sup 17} and 5.0 x 10{sup 17} cm{sup -2} into <1 1 1> single crystal silicon substrates held at elevated temperature (410 deg. C). The structures of ion-beam synthesized buried silicon nitride layers were studied by X-ray diffraction (XRD) technique. The XRD studies reveal the formation of hexagonal silicon nitride (Si{sub 3}N{sub 4}) structure at all fluences. The concentration of the silicon nitride phase was found to be dependent on the ion fluence. The intensity and full width at half maximum (FWHM) of XRD peak were found to increase with increase in ion fluence. The Raman spectra for samples implanted with different ion fluences show crystalline silicon (c-Si) substrate peak at wavenumber 520 cm{sup -1}. The intensity of the silicon peak was found to decrease with increase in ion fluence.

  19. Characterization of nitrogen-fixing bacteria from a temperate saltmarsh lagoon, including isolates that produce ethane from acetylene.

    Science.gov (United States)

    Tibbles, B J; Rawlings, D E

    1994-01-01

    Nitrogen-fixing bacteria were isolated from sediments and water of a saltmarsh lagoon on the west coast of South Africa, and characterized according to factors that regulate nitrogen fixation in the marine environment. The majority of isolates were assigned to the Photobacterium or Vibrio genera on the basis of physiological and biochemical characteristics. One isolate was further assigned to the species Vibrio diazotrophicus. Carbohydrate utilization by each diazotrophic isolate was examined. Abilities of the isolates to utilize a range of mono-, di-, and polysaccharides largely reflected the predicted availability of organic carbon and energy in the lagoon, except that chitin was not utilized. Biochemical tests on the utilization of combined nitrogen showed that one isolate could utilize nitrate, and that this strain was susceptible to full repression of nitrogenase activity by 10mM nitrate. Urease activity was not detected in any of the isolates. In the absence of molybdenum two of the isolates, a Photobacterium spp. and V. diazotrophicus, reduced acetylene to ethylene and ethane, a property frequently associated with the activity of alternative nitrogenases. Addition of 25µM molybdenum inhibited ethane production by V. diazotrophicus, but stimulated ethylene and ethane production by the Photobacterium isolate. Addition of 28µM vanadium did not appear to regulate ethane production by either strain. Assays of nitrogenase activity in sediments from which some isolates were obtained indicated that molybdenum was not limiting nitrogenase activity at naturally-occurring concentrations. Southern hybridizations of the chromosomes of these strains with the anfH and vnfH genes of Azotobacter vinelandii and the nifH gene of Klebsiella pneumoniae indicated the presence of only one nitrogenase in these isolates.

  20. Isolation of novel ribozymes that ligate AMP-activated RNA substrates

    Science.gov (United States)

    Hager, A. J.; Szostak, J. W.

    1997-01-01

    BACKGROUND: The protein enzymes RNA ligase and DNA ligase catalyze the ligation of nucleic acids via an adenosine-5'-5'-pyrophosphate 'capped' RNA or DNA intermediate. The activation of nucleic acid substrates by adenosine 5'-monophosphate (AMP) may be a vestige of 'RNA world' catalysis. AMP-activated ligation seems ideally suited for catalysis by ribozymes (RNA enzymes), because an RNA motif capable of tightly and specifically binding AMP has previously been isolated. RESULTS: We used in vitro selection and directed evolution to explore the ability of ribozymes to catalyze the template-directed ligation of AMP-activated RNAs. We subjected a pool of 10(15) RNA molecules, each consisting of long random sequences flanking a mutagenized adenosine triphosphate (ATP) aptamer, to ten rounds of in vitro selection, including three rounds involving mutagenic polymerase chain reaction. Selection was for the ligation of an oligonucleotide to the 5'-capped active pool RNA species. Many different ligase ribozymes were isolated; these ribozymes had rates of reaction up to 0.4 ligations per hour, corresponding to rate accelerations of approximately 5 x10(5) over the templated, but otherwise uncatalyzed, background reaction rate. Three characterized ribozymes catalyzed the formation of 3'-5'-phosphodiester bonds and were highly specific for activation by AMP at the ligation site. CONCLUSIONS: The existence of a new class of ligase ribozymes is consistent with the hypothesis that the unusual mechanism of the biological ligases resulted from a conservation of mechanism during an evolutionary replacement of a primordial ribozyme ligase by a more modern protein enzyme. The newly isolated ligase ribozymes may also provide a starting point for the isolation of ribozymes that catalyze the polymerization of AMP-activated oligonucleotides or mononucleotides, which might have been the prebiotic analogs of nucleoside triphosphates.

  1. Characterization and activity of visible-light-driven TiO 2 photocatalyst codoped with nitrogen and cerium

    Science.gov (United States)

    Liu, Chao; Tang, Xinhu; Mo, Cehui; Qiang, Zhimin

    2008-04-01

    Nitrogen and cerium codoped TiO 2 photocatalysts were prepared by a modified sol-gel process with doping precursors of cerium nitrate and urea, and characterized by X-ray diffraction (XRD), thermogravimetry-differential scanning calorimetry (TG-DSC), X-ray photoelectron spectra (XPS) and ultraviolet-visible light diffuse reflectance spectra (UV-vis DRS). Results indicate that anatase TiO 2 is the dominant crystalline type in as-prepared samples, and CeO 2 crystallites appear as the doping ratio of Ce/Ti reaches to 3.0 at%. The TiO 2 starts to transform from amorphous phase to anatase at 987.1 K during calcination, according to the TG-DSC curves. The XPS show that three major metal ions of Ce 3+, Ce 4+, Ti 4+ and one minor metal ion of Ti 3+ coexist on the surface. The codoped TiO 2 exhibits significant absorption within the range of 400-500 nm compared to the non-doped and only nitrogen-doped TiO 2. The enhanced photocatalytic activity of the codoped TiO 2 is demonstrated through degradation of methyl orange under visible light irradiation.

  2. Synthesis, Characterization, and Density Functional Theory Analysis of Uranium and Thorium Complexes Containing Nitrogen-Rich 5-Methyltetrazolate Ligands.

    Science.gov (United States)

    Browne, Kevin P; Maerzke, Katie A; Travia, Nicholas E; Morris, David E; Scott, Brian L; Henson, Neil J; Yang, Ping; Kiplinger, Jaqueline L; Veauthier, Jacqueline M

    2016-05-16

    Two nitrogen-rich, isostructural complexes of uranium and thorium, (C5Me5)2U[η(2)-(N,N')-tetrazolate]2 (7) and (C5Me5)2Th[η(2)-(N,N')-tetrazolate]2 (8), containing 5-methyltetrazolate, have been synthesized and structurally characterized by single-crystal X-ray diffraction, electrochemical methods, UV-visible-near-IR spectroscopy, and variable-temperature (1)H NMR spectroscopy. Density functional theory (DFT) calculations yield favorable free energies of formation (approximately -375 kJ/mol) and optimized structures in good agreement with the experimental crystal structures. Additionally, calculated NMR chemical shifts of 7 and 8 are in good agreement with the variable-temperature (1)H NMR experiments. Time-dependent DFT calculations of both complexes yield UV-visible spectroscopic features that are consistent with experiment and provide assignments of the corresponding electronic transitions. The electronic transitions in the UV-visible spectroscopic region are attributed to C5Me5 ligand-to-metal charge transfer. The low-lying molecular orbitals of the tetrazolate ligands (∼2 eV below the HOMO) do not contribute appreciably to experimentally observed electronic transitions. The combined experimental and theoretical analysis of these new nitrogen-rich uranium and thorium complexes indicates the tetrazolate ligand behaves primarily as a σ-donor.

  3. Mechanical characterization of selected adhesives and bulk materials at liquid nitrogen and room temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Fitzpatrick, C.M.; Stoddart, W.C.T.

    1977-01-01

    This paper presents the results of a series of mechanical tests on selected adhesives and bulk materials. The materials tested are of general interest to designers of magnets for cryogenic service and include several epoxies, a varnish, a B-stage glass cloth, insulation papers, and commercially available fiber-reinforced composites. These tests were performed at room temperature (293 K) and at liquid nitrogen temperature (77 K). The tests include both simple tension tests and lap shear tests with various adherends. The parameters critical to tensile or bond strength were varied as part of the test program. The procedures used to manufacture and test these specimens and the results of the tests are reported in this paper.

  4. Growth and characterization of BCN nanotubes with high boron and nitrogen content

    Indian Academy of Sciences (India)

    Guo Zhang; Zhiye Liu; Lianping Zhang; Liqiang Jing; Keying Shi

    2013-09-01

    Multiwalled carbon nanotubes doped with boron and nitrogen (BCNTs) have been synthesized by chemical vapour deposition at temperatures ranging from 800°C to 950°C. Their morphological and structural features have been studied by transmission electron microscope, which reveal that BCNTs have bamboo-like structure. The results of X-ray photoelectron spectroscopy demonstrated that the atomic ratio of B, C and N of BCNTs is about 1:4:1, when temperature is 850°C. Electrooxidation performance of the BCNTs for NO at the modified electrodes was investigated. The results of cyclic voltammograms and the electrochemical impedance spectroscopy of BCNT-modified electrodes indicated that the activity of NO electrooxidation on 850°C-modified electrodes is much stronger than others and the charge transfer resistance of NO electroxidation BCNT-modified electrode is the least. By this means, BCNT-modified electrodes showed excellent electrode materials for NO detection and other potential applications.

  5. Synthesis and characterization of homogeneous interstitial solutions of nitrogen and carbon in iron-based lattices

    DEFF Research Database (Denmark)

    Brink, Bastian Klüge

    work in synthesis and characterization of interstitial solutions ofnitrogen and carbon in iron-based lattices. In order to avoid the influences of gradients incomposition and residual stresses, which are typically found in treated surface layers,homogenous samples are needed. These were prepared from...... pure iron or austeniticstainless steel using gaseous mixtures of ammonia, hydrogen, acetylene and propene atelevated temperatures.Structural and magnetic properties have been characterized with neutron diffraction,vibrating sample magnetometry and Mössbauer spectroscopy. Thermal expansion...

  6. Platinum incorporation in the Na Y zeolite through impregnation method, and characterization by XRD, FTIR and nitrogen adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, A.S.; Sousa, B.V.; Andrade, A.C.C.; Rodrigues, M.G.F. [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Centro de Ciencias e Tecnologia. Unidade Academica de Engenharia Quimica], e-mail: alfredinad@yahoo.com.br, e-mail: biancaviana_cg@yahoo.com.br, e-mail: meiry@deq.ufcg.edu.br; Rangel, M.C. [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil). Inst. de Quimica. Grupo de Estudos em Cinetica e Catalise

    2007-07-01

    Supported metal catalysts are widely used in petroleum refining, chemical and petroleum industries. These catalysts are important in ammonia synthesis, conversion of hydrocarbons with water vapor to synthesis gas, reforming, hydrocracking, ... Platinum has long been used in cracking, hydrogenation and dehydrogenation processes. The aim of this project is the Na Y zeolitic sample preparation through impregnation for incipient humidity, with 0,5% concentration of platinum, aiming its use as a catalyst in the steam reforming reaction. The characterization techniques used were: X Rays Diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR) and Nitrogen Adsorption (BET Method). From the obtained results through the techniques mentioned previously it is possible to evidence that the platinum impregnation process did not change the Na Y zeolite structure. Through the superficial specific area (BET) it was possible to observe that the platinum impregnation process caused a decrease in the specific area due to the reduction to the accessibility to the micropores of the zeolitic structure. (author)

  7. Surface characterization and biocompatibility of titanium alloys implanted with nitrogen by Hardion+ technology.

    Science.gov (United States)

    Gordin, D M; Gloriant, T; Chane-Pane, V; Busardo, D; Mitran, V; Höche, D; Vasilescu, C; Drob, S I; Cimpean, A

    2012-12-01

    In this study, the new Hardion+ micro-implanter technology was used to modify surface properties of biomedical pure titanium (CP-Ti) and Ti-6Al-4V ELI alloy by implantation of nitrogen ions. This process is based on the use of an electron cyclotron resonance ion source to produce a multienergetic ion beam from multicharged ions. After implantation, surface analysis methods revealed the formation of titanium nitride (TiN) on the substrate surfaces. An increase in superficial hardness and a significant reduction of friction coefficient were observed for both materials when compared to non-implanted samples. Better corrosion resistance and a significant decrease in ion release rates were observed for N-implanted biomaterials due to the formation of the protective TiN layer on their surfaces. In vitro tests performed on human fetal osteoblasts indicated that the cytocompatibility of N-implanted CP-Ti and Ti-6Al-4V alloy was enhanced in comparison to that of the corresponding non treated samples. Consequently, Hardion+ implantation technique can provide titanium alloys with better qualities in terms of corrosion resistance, cell proliferation, adhesion and viability.

  8. Biochemical characterization of reactive nitrogen species by eosinophil peroxidase in tyrosine nitration

    Directory of Open Access Journals (Sweden)

    Hitomi,Yoshiaki

    2007-02-01

    Full Text Available It is well known that eosinophils are involved in tyrosine nitration. In this study, we evaluated tyrosine nitration by rat eosinophils isolated from peritoneal fl uid and constituent eosinophils in the stomach. Rat peritoneal eosinophils activated with 1 μM phorbol myristate acetate (PMA and 50 μM NO2 ン showed immunostaining for nitrotyrosine only in smaller cells, despite the fact that eosinophils are capable of producing superoxide (O2·ン. Free tyrosine nitrating capacity after incubation with PMA and NO2 ン was 4-fold higher in eosinophils than in neutrophils. Catalase and ク- and コ -tocopherol inhibited free tyrosine nitration by reactive nitrogen species from eosinophils but not that by peroxynitrite. Superoxide dismutase augmented free tyrosine nitration by activated eosinophils and peroxynitrite. The concentration of nitric oxide released from eosinophils was relatively low (0.32 μM/106 cells/h and did not contribute to the formation of nitrotyrosine. On the other hand, most constituent eosinophils constituent in the rat stomach stimulated by PMA and NO2 ン showed tyrosine nitration capacity. These results suggest that intact cells other than apoptotic-like eosinophils eluted in the intraperitoneal cavity could not generate reactive species responsible for nitration by a peroxidase-dependent mechanism. In contrast, normal eosinophils in the stomach were capable of nitration, suggesting that the characteristics of eosinophils in gastric mucosa are diff erent from those eluted in the peritoneal cavity.

  9. Characterization of second generation biomass under thermal conversion and the fate of nitrogen

    NARCIS (Netherlands)

    Giuntoli, J.

    2010-01-01

    This dissertation deals with the characterization of several biomass materials under thermal conversion conditions using small--scale equipment. The fuels are tested under the conditions of slow and fast heating rate pyrolysis and combustion, with the main goal of investigating the chemistry of fuel

  10. Staudinger Ligation of Peptides at Non-Glycyl Residues

    OpenAIRE

    Soellner, Matthew B.; Tam, Annie; Raines, Ronald T.

    2006-01-01

    The Staudinger ligation provides a means to form an amide bond between a phosphinothioester and azide. This reaction holds promise for the ligation of peptides en route to the total chemical synthesis of proteins. (Diphenylphosphino)methanethiol is the most efficacious of known reagents for mediating the Staudinger ligation of peptides, providing high (>90%) isolated yields for equimolar couplings in which a glycine residue is at the nascent junction. Surprisingly, the yields are lower (80%) ...

  11. The HubBLe trial: haemorrhoidal artery ligation (HAL versus rubber band ligation (RBL for haemorrhoids

    Directory of Open Access Journals (Sweden)

    Tiernan Jim

    2012-10-01

    Full Text Available Abstract Background Haemorrhoids (piles are a very common condition seen in surgical clinics. After exclusion of more sinister causes of haemorrhoidal symptoms (rectal bleeding, perianal irritation and prolapse, the best option for treatment depends upon persistence and severity of the symptoms. Minor symptoms often respond to conservative treatment such as dietary fibre and reassurance. For more severe symptoms treatment such as rubber band ligation may be therapeutic and is a very commonly performed procedure in the surgical outpatient setting. Surgery is usually reserved for those who have more severe symptoms, as well as those who do not respond to non-operative therapy; surgical techniques include haemorrhoidectomy and haemorrhoidopexy. More recently, haemorrhoidal artery ligation has been introduced as a minimally invasive, non destructive surgical option. There are substantial data in the literature concerning efficacy and safety of 'rubber band ligation including multiple comparisons with other interventions, though there are no studies comparing it to haemorrhoidal artery ligation. A recent overview has been carried out by the National Institute for Health and Clinical Excellence which concludes that current evidence shows haemorrhoidal artery ligation to be a safe alternative to haemorrhoidectomy and haemorrhoidopexy though it also highlights the lack of good quality data as evidence for the advantages of the technique. Methods/design The aim of this study is to establish the clinical effectiveness and cost effectiveness of haemorrhoidal artery ligation compared with conventional rubber band ligation in the treatment of people with symptomatic second or third degree (Grade II or Grade III haemorrhoids. Design: A multi-centre, parallel group randomised controlled trial. Outcomes: The primary outcome is patient-reported symptom recurrence twelve months following the intervention. Secondary outcome measures relate to symptoms

  12. 16S ribosomal DNA characterization of nitrogen-fixing bacteria isolated from banana (Musa spp.) and pineapple (Ananas comosus (L.) Merril).

    Science.gov (United States)

    Magalhães Cruz, L; de Souza, E M; Weber, O B; Baldani, J I; Döbereiner, J; Pedrosa, F de O

    2001-05-01

    Nitrogen-fixing bacteria isolated from banana (Musa spp.) and pineapple (Ananas comosus (L.) Merril) were characterized by amplified 16S ribosomal DNA restriction analysis and 16S rRNA sequence analysis. Herbaspirillum seropedicae, Herbaspirillum rubrisubalbicans, Burkholderia brasilensis, and Burkholderia tropicalis were identified. Eight other types were placed in close proximity to these genera and other alpha and beta Proteobacteria.

  13. Principles and applications of Ligation Mediated PCR methods for DNA-based typing of microbial organisms.

    Science.gov (United States)

    Krawczyk, Beata; Kur, Józef; Stojowska-Swędrzyńska, Karolina; Śpibida, Marta

    2016-01-01

    A significant number of DNA-based techniques has been introduced into the field of microorganisms' characterization and taxonomy. These genomic fingerprinting methods were developed to detect DNA sequence polymorphisms by using general principles, such as restriction endonuclease analysis, molecular hybridization, and PCR amplification. In recent years, some alternative techniques based on ligation of oligonucleotide adapters before DNA amplification by PCR, known as Ligation-Mediated PCR methods (LM PCR), have been successfully applied for the typing of microorganisms below the species level. These molecular methods include: Amplified Fragment Length Polymorphism (AFLP), Amplification of DNA fragments Surrounding Rare Restriction Sites (ADSRRS), PCR Melting Profiles (PCR MP), Ligation Mediated PCR/Shifter (LM PCR/Shifter), Infrequent-Restriction-Site Amplification (IRS PCR), double digestion Ligation Mediated Suppression PCR (ddLMS PCR). These techniques are now applied more and more often because they involve less time, are comparably inexpensive, and require only standard lab equipment. Here, we present a general review of this group of methods showing their possibilities and limitations. We also identify questions and propose solutions which may be helpful in choosing a particular LM PCR method for the achievement of the required goal.

  14. Streamlined expressed protein ligation using split inteins.

    Science.gov (United States)

    Vila-Perelló, Miquel; Liu, Zhihua; Shah, Neel H; Willis, John A; Idoyaga, Juliana; Muir, Tom W

    2013-01-09

    Chemically modified proteins are invaluable tools for studying the molecular details of biological processes, and they also hold great potential as new therapeutic agents. Several methods have been developed for the site-specific modification of proteins, one of the most widely used being expressed protein ligation (EPL) in which a recombinant α-thioester is ligated to an N-terminal Cys-containing peptide. Despite the widespread use of EPL, the generation and isolation of the required recombinant protein α-thioesters remain challenging. We describe here a new method for the preparation and purification of recombinant protein α-thioesters using engineered versions of naturally split DnaE inteins. This family of autoprocessing enzymes is closely related to the inteins currently used for protein α-thioester generation, but they feature faster kinetics and are split into two inactive polypeptides that need to associate to become active. Taking advantage of the strong affinity between the two split intein fragments, we devised a streamlined procedure for the purification and generation of protein α-thioesters from cell lysates and applied this strategy for the semisynthesis of a variety of proteins including an acetylated histone and a site-specifically modified monoclonal antibody.

  15. Preparation and characterization of visible-light-driven TiO2 photocatalyst Co-doped with nitrogen and erbium.

    Science.gov (United States)

    Chen, Guihua; Wang, Yong; Zhang, Juihui; Wu, Chenglin; Liang, Huading; Yang, Hui

    2012-05-01

    A series of nitrogen and erbium co-doped TiO2 photocatalyst was prepared by sol-hydrothermal method. The structure and properties of the photocatalyst were characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) method, X-ray photoelectron spectroscopy (XPS), and UV-vis diffuse reflectance spectra (DRS). The XRD and BET results showed that co-doping inhibited the increase of crystallite size and enlarged specific surface areas. XPS spectroscopy indicated nitrogen atoms were incorporated into TiO2 lattice, and erbium atoms mostly existed in the forms of Er2O3. A shift of the absorption edge to the lower energy and four absorption bands located at 654, 544, 524 and 489 nm attributed to the 4f transitions of 4I15/2 --> 4F2/9, 4I15/2 --> 4S3/2, 4I15/2 --> 2H11/2, 4I15/2 --> 4F7/2 of Er3+ were observed using DRS spectroscopy. The catalytic efficency was evaluated by the photocatalytic degradation of methyl orange (MO) under visible light irradiation. The results showed that the photocatalytic performance of the co-doped TiO2 was related with the hydrothermal temperature and the molar ratio of N/Ti, and they showed higher acitivites than pure TiO2. Results determined by fluorescence technique revealed that irradiation (lambda > 400 nm) of TiO2 photocatalyst dispersed in MO solution induces the generation of the highly active hydroxyl radicals (OH). It indicated the photocatalytic activities of TiO2 photocatalyst were correlation with the formation rate of hydroxyl radicals (OH) and other active oxygen species.

  16. Characterization of a Mesorhizobium loti α-Type Carbonic Anhydrase and Its Role in Symbiotic Nitrogen Fixation▿

    Science.gov (United States)

    Kalloniati, Chrysanthi; Tsikou, Daniela; Lampiri, Vasiliki; Fotelli, Mariangela N.; Rennenberg, Heinz; Chatzipavlidis, Iordanis; Fasseas, Costas; Katinakis, Panagiotis; Flemetakis, Emmanouil

    2009-01-01

    Carbonic anhydrase (CA) (EC 4.2.1.1) is a widespread enzyme catalyzing the reversible hydration of CO2 to bicarbonate, a reaction that participates in many biochemical and physiological processes. Mesorhizobium loti, the microsymbiont of the model legume Lotus japonicus, possesses on the symbiosis island a gene (msi040) encoding an α-type CA homologue, annotated as CAA1. In the present work, the CAA1 open reading frame from M. loti strain R7A was cloned, expressed, and biochemically characterized, and it was proven to be an active α-CA. The biochemical and physiological roles of the CAA1 gene in free-living and symbiotic rhizobia were examined by using an M. loti R7A disruption mutant strain. Our analysis revealed that CAA1 is expressed in both nitrogen-fixing bacteroids and free-living bacteria during growth in batch cultures, where gene expression was induced by increased medium pH. L. japonicus plants inoculated with the CAA1 mutant strain showed no differences in top-plant traits and nutritional status but consistently formed a higher number of nodules exhibiting higher fresh weight, N content, nitrogenase activity, and δ13C abundance. Based on these results, we propose that although CAA1 is not essential for nodule development and symbiotic nitrogen fixation, it may participate in an auxiliary mechanism that buffers the bacteroid periplasm, creating an environment favorable for NH3 protonation, thus facilitating its diffusion and transport to the plant. In addition, changes in the nodule δ13C abundance suggest the recycling of at least part of the HCO3− produced by CAA1. PMID:19218391

  17. Characterization of a Mesorhizobium loti alpha-type carbonic anhydrase and its role in symbiotic nitrogen fixation.

    Science.gov (United States)

    Kalloniati, Chrysanthi; Tsikou, Daniela; Lampiri, Vasiliki; Fotelli, Mariangela N; Rennenberg, Heinz; Chatzipavlidis, Iordanis; Fasseas, Costas; Katinakis, Panagiotis; Flemetakis, Emmanouil

    2009-04-01

    Carbonic anhydrase (CA) (EC 4.2.1.1) is a widespread enzyme catalyzing the reversible hydration of CO(2) to bicarbonate, a reaction that participates in many biochemical and physiological processes. Mesorhizobium loti, the microsymbiont of the model legume Lotus japonicus, possesses on the symbiosis island a gene (msi040) encoding an alpha-type CA homologue, annotated as CAA1. In the present work, the CAA1 open reading frame from M. loti strain R7A was cloned, expressed, and biochemically characterized, and it was proven to be an active alpha-CA. The biochemical and physiological roles of the CAA1 gene in free-living and symbiotic rhizobia were examined by using an M. loti R7A disruption mutant strain. Our analysis revealed that CAA1 is expressed in both nitrogen-fixing bacteroids and free-living bacteria during growth in batch cultures, where gene expression was induced by increased medium pH. L. japonicus plants inoculated with the CAA1 mutant strain showed no differences in top-plant traits and nutritional status but consistently formed a higher number of nodules exhibiting higher fresh weight, N content, nitrogenase activity, and delta(13)C abundance. Based on these results, we propose that although CAA1 is not essential for nodule development and symbiotic nitrogen fixation, it may participate in an auxiliary mechanism that buffers the bacteroid periplasm, creating an environment favorable for NH(3) protonation, thus facilitating its diffusion and transport to the plant. In addition, changes in the nodule delta(13)C abundance suggest the recycling of at least part of the HCO(3)(-) produced by CAA1.

  18. Molecular characterization of water soluble organic nitrogen in marine rainwater by ultra-high resolution electrospray ionization mass spectrometry

    Directory of Open Access Journals (Sweden)

    K. E. Altieri

    2011-11-01

    Full Text Available Atmospheric water soluble organic nitrogen (WSON is a subset of the complex organic matter in aerosols and rainwater, which impacts cloud condensation processes and aerosol chemical and optical properties, and may play a significant role in the biogeochemical cycle of N. However, its sources, composition, connections to inorganic N, and variability are largely unknown. Rainwater samples were collected on the island of Bermuda (32.27° N, 64.87° W, which experiences both anthropogenic and marine influenced air masses. Samples were analyzed by ultra-high resolution electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry to chemically characterize the WSON. Elemental compositions of 2455 N containing compounds were determined over the mass range m/z+ 50 to 500. The five compound classes with the largest number of elemental formulas identified, in order from the highest number of formulas to the lowest, contained carbon, hydrogen, oxygen, and nitrogen (CHON+, CHON compounds that contained sulfur (CHONS+, CHON compounds that contained phosphorous (CHONP+, CHON compounds that contained both sulfur and phosphorous (CHONSP+, and compounds that contained only carbon, hydrogen, and nitrogen (CHN+. No organonitrates or nitrooxy-organosulfates were detected, but there was an increased presence of organic S and organic P containing compounds in the marine rainwater. Compared to rainwater collected in the continental USA, average O:C ratios of all N containing compound classes were lower in the marine samples whereas double bond equivalent values were higher, suggesting a reduced role of secondary formation mechanisms. Cluster analysis showed a clear chemical distinction between samples collected during the cold season (October to March which have anthropogenic air mass origins and samples collected during the warm season (April to September with remote marine air mass origins. This, in conjunction with patterns

  19. Molecular characterization of water soluble organic nitrogen in marine rainwater by ultra-high resolution electrospray ionization mass spectrometry

    Science.gov (United States)

    Altieri, K. E.; Hastings, M. G.; Peters, A. J.; Sigman, D. M.

    2012-04-01

    Atmospheric water soluble organic nitrogen (WSON) is a subset of the complex organic matter in aerosols and rainwater, which impacts cloud condensation processes and aerosol chemical and optical properties and may play a significant role in the biogeochemical cycle of N. However, its sources, composition, connections to inorganic N, and variability are largely unknown. Rainwater samples were collected on the island of Bermuda (32.27° N, 64.87° W), which experiences both anthropogenic and marine influenced air masses. Samples were analyzed by ultra-high resolution electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry to chemically characterize the WSON. Elemental compositions of 2281 N containing compounds were determined over the mass range m/z+ 50 to 500. The five compound classes with the largest number of elemental formulas identified, in order from the highest number of formulas to the lowest, contained carbon, hydrogen, oxygen, and nitrogen (CHON+), CHON compounds that contained sulfur (CHONS+), CHON compounds that contained phosphorus (CHONP+), CHON compounds that contained both sulfur and phosphorus (CHONSP+), and compounds that contained only carbon, hydrogen, and nitrogen (CHN+). Compared to rainwater collected in the continental USA, average O:C ratios of all N containing compound classes were lower in the marine samples whereas double bond equivalent values were higher, suggesting a reduced role of secondary formation mechanisms. Despite their prevalence in continental rainwater, no organonitrates or nitrooxy-organosulfates were detected, but there was an increased presence of organic S and organic P containing compounds in the marine rainwater. Cluster analysis showed a clear chemical distinction between samples collected during the cold season (October to March) which have anthropogenic air mass origins and samples collected during the warm season (April to September) with remote marine air mass origins. This, in

  20. Evaluation of a soil incubation method to characterize nitrogen release patterns of slow- and controlled-release fertilizers.

    Science.gov (United States)

    Medina, L Carolina; Sartain, Jerry B; Obreza, Thomas A; Hall, William L; Thiex, Nancy J

    2014-01-01

    Several technologies have been proposed to characterize the nutrient release patterns of slow-release fertilizers (SRF) and controlled-release fertilizers (CRF) during the last few decades. These technologies have been developed mainly by manufacturers, and are product-specific, based on the regulation and analysis of each SRF and CRF product. Despite previous efforts to characterize SRF and CRF materials, no standardized, validated method exists to assess their nutrient release patterns. However, the increased production and distribution of these materials in specialty and nonspecialty markets requires an appropriate method to verify product claims and material performance. A soil incubation column leaching procedure was evaluated to determine its suitability as a standard method to estimate nitrogen (N) release patterns of SRFs and CRFs during 180 days. The influence of three soil/sand ratios, three incubation temperatures, and four soils on method behavior was assessed using five SRFs and three CRFs. In general, the highest soil/sand ratio increased the N release rate of all materials, but this effect was more marked for the SRFs. Temperature had the greatest influence on N release rates. For CRFs, the initial N release rates and the percentage N released/day increased as temperature increased. For SRFs, raising the temperature from 25 to 35 degreesC increased initial N release rate and the total cumulative N released, and almost doubled the percentage released/day. The percentage N released/day from all products generally increased as the texture of the soil changed from sandy to loamy (lowa>California>Pennsylvania>Florida). The soil incubation technique was demonstrated to be robust and reliable for characterizing N release patterns from SRFs and CRFs. The method was reproducible, and variations in soil/sand ratio, temperature, and soil had little effect on the results.

  1. Imidazole-based Potential Bi- and Tridentate Nitrogen Ligands: Synthesis, Characterization and Application in Asymmetric Catalysis

    Directory of Open Access Journals (Sweden)

    Jiří Kulhánek

    2008-09-01

    Full Text Available Twelve new imidazole-based potential bi- and tridentate ligands were synthesized and characterized. Whereas in the first series the α-amino acid and imidazole moieties were linked by an amino bond, in the second series the tridentate ligands, containing two imidazole groups, were separated by an amide bond. The first series was obtained by the reductive amination of 2-phenylimidazole-4-carboxaldehyde with α-amino acid esters. The tridentate ligands were prepared from 2-phenylimidazole-4-carboxylic acid and chiral amines. In the Henry reaction, the amines were revealed as a more reactive species than the less nucleophilic amides, however the enantiomeric excesses were generally poor.

  2. Structural characterization of an acidic exoheteropolysaccharide produced by the nitrogen-fixing bacterium Burkholderia tropica.

    Science.gov (United States)

    Serrato, Rodrigo V; Sassaki, Guilherme L; Gorin, Philip A J; Cruz, Leonardo M; Pedrosa, Fábio O; Choudhury, Biswa; Carlson, Russell W; Iacomini, Marcello

    2008-09-05

    An acidic exopolysaccharide (EPS) produced by the diazotrophic bacterium Burkholderia tropica, strain Ppe8, was isolated from the culture supernatant of bacteria grown in a synthetic liquid medium containing mannitol and glutamate. Monosaccharide composition showed Rha, Glc and GlcA in a 2.0:2.0:1.0 molar ratio, respectively. Further structural characterization was performed by a combination of NMR, mass spectrometry and chemical methods. Partial acid hydrolysis of EPS provided a mixture of acidic oligosaccharides that were characterized by ESI-MS, giving rise to ions with m/z 193 (GlcA-H)(-), 339 (GlcA,Rha-H)(-), 501 (GlcA,Rha,Glc-H)(-), 647 (GlcA,Rha2,Glc,-H)(-), 809 (GlcA,Rha2,Glc2,-H)(-) and 851 (GlcA,Rha2,Glc2,OAc-H)(-). Carboxyreduced EPS (EPS-CR) had Glc and Rha in a 3:2 ratio, present as d- and l-enantiomers, respectively. Methylation and NMR analysis of EPS and EPS-CR showed a main chain containing 2,4-di-O-Rhap, 3-O-Rhap and 4-O-Glcp. A GlcA side chain unit was found in the acidic EPS, substituting O-4 of α-l-Rhap units. This was observed as a non-reducing end unit of glucopyranose in the EPS-CR. Acetyl esters occured at O-2 of β-l-Rhap units. From the combined results herein, we determined the structure of the exocellular polysaccharide produced by B. tropica, Ppe8, as being a pentasaccharide repeating unit as shown.

  3. Serum markers of the extracellular matrix remodeling reflect antifibrotic therapy in bile-duct ligated rats

    OpenAIRE

    Robert eSchierwagen; Sabine eKlein; Diana Julie Leeming; Michaela eGranzow; Mette Juul Nielsen; Tilman eSauerbruch; Aleksander eKrag; Morten A Karlsdal; Jonel eTrebicka

    2013-01-01

    BackgroundProgression of liver fibrosis is characterized by synthesis and degradation of extracellular matrix (ECM). Matrix-metalloproteinases (MMP) cleave collagen fibers at a specific site and thereby generate soluble fragments of ECM (neo-epitopes). The levels of these neo-epitopes might reflect the stage of liver fibrosis and may allow monitoring of anti-fibrotic therapies. Here we analyzed these neo-epitopes as read-out for a liver directed therapy with statins.MethodsBile duct ligation ...

  4. Tubal ligation and risk of ovarian cancer subtypes

    DEFF Research Database (Denmark)

    Sieh, Weiva; Salvador, Shannon; McGuire, Valerie;

    2013-01-01

    Tubal ligation is a protective factor for ovarian cancer, but it is unknown whether this protection extends to all invasive histological subtypes or borderline tumors. We undertook an international collaborative study to examine the association between tubal ligation and ovarian cancer subtypes....

  5. Ligation bias in illumina next-generation DNA libraries: implications for sequencing ancient genomes.

    Science.gov (United States)

    Seguin-Orlando, Andaine; Schubert, Mikkel; Clary, Joel; Stagegaard, Julia; Alberdi, Maria T; Prado, José Luis; Prieto, Alfredo; Willerslev, Eske; Orlando, Ludovic

    2013-01-01

    Ancient DNA extracts consist of a mixture of endogenous molecules and contaminant DNA templates, often originating from environmental microbes. These two populations of templates exhibit different chemical characteristics, with the former showing depurination and cytosine deamination by-products, resulting from post-mortem DNA damage. Such chemical modifications can interfere with the molecular tools used for building second-generation DNA libraries, and limit our ability to fully characterize the true complexity of ancient DNA extracts. In this study, we first use fresh DNA extracts to demonstrate that library preparation based on adapter ligation at AT-overhangs are biased against DNA templates starting with thymine residues, contrarily to blunt-end adapter ligation. We observe the same bias on fresh DNA extracts sheared on Bioruptor, Covaris and nebulizers. This contradicts previous reports suggesting that this bias could originate from the methods used for shearing DNA. This also suggests that AT-overhang adapter ligation efficiency is affected in a sequence-dependent manner and results in an uneven representation of different genomic contexts. We then show how this bias could affect the base composition of ancient DNA libraries prepared following AT-overhang ligation, mainly by limiting the ability to ligate DNA templates starting with thymines and therefore deaminated cytosines. This results in particular nucleotide misincorporation damage patterns, deviating from the signature generally expected for authenticating ancient sequence data. Consequently, we show that models adequate for estimating post-mortem DNA damage levels must be robust to the molecular tools used for building ancient DNA libraries.

  6. Ligation bias in illumina next-generation DNA libraries: implications for sequencing ancient genomes.

    Directory of Open Access Journals (Sweden)

    Andaine Seguin-Orlando

    Full Text Available Ancient DNA extracts consist of a mixture of endogenous molecules and contaminant DNA templates, often originating from environmental microbes. These two populations of templates exhibit different chemical characteristics, with the former showing depurination and cytosine deamination by-products, resulting from post-mortem DNA damage. Such chemical modifications can interfere with the molecular tools used for building second-generation DNA libraries, and limit our ability to fully characterize the true complexity of ancient DNA extracts. In this study, we first use fresh DNA extracts to demonstrate that library preparation based on adapter ligation at AT-overhangs are biased against DNA templates starting with thymine residues, contrarily to blunt-end adapter ligation. We observe the same bias on fresh DNA extracts sheared on Bioruptor, Covaris and nebulizers. This contradicts previous reports suggesting that this bias could originate from the methods used for shearing DNA. This also suggests that AT-overhang adapter ligation efficiency is affected in a sequence-dependent manner and results in an uneven representation of different genomic contexts. We then show how this bias could affect the base composition of ancient DNA libraries prepared following AT-overhang ligation, mainly by limiting the ability to ligate DNA templates starting with thymines and therefore deaminated cytosines. This results in particular nucleotide misincorporation damage patterns, deviating from the signature generally expected for authenticating ancient sequence data. Consequently, we show that models adequate for estimating post-mortem DNA damage levels must be robust to the molecular tools used for building ancient DNA libraries.

  7. A new 10-min ligation method using a modified buffer system with a very low amount of T4 DNA ligase: the "Coffee Break Ligation" technique.

    Science.gov (United States)

    Yoshino, Yuki; Ishida, Masaharu; Horii, Akira

    2007-10-01

    The ligation reaction is widely used in molecular biology. There are several kits available that complete the ligation reaction very rapidly but they are rather expensive. In this study, we successfully modified the ligation buffer with much lower cost than existing kits. The ligation reaction can be completed in 10 min using very low activities such as 0.01 U T4 DNA ligase, and costs only $1 for 100 reactions of 20 microl scale. We name this ligation system the "Coffee Break Ligation" system; one can complete ligation reaction while drinking a cup of coffee, and perform 100 reactions by spending money equivalent to a cup of coffee.

  8. Biochemical characterization of a nitrogen-type phosphotransferase system reveals that enzyme EI(Ntr) integrates carbon and nitrogen signaling in Sinorhizobium meliloti.

    Science.gov (United States)

    Goodwin, Reed A; Gage, Daniel J

    2014-05-01

    In Sinorhizobium meliloti, catabolite repression is influenced by a noncanonical nitrogen-type phosphotransferase system (PTS(Ntr)). In this PTS(Ntr), the protein HPr is phosphorylated on histidine-22 by the enzyme EI(Ntr) and the flux of phosphate through this residue onto downstream proteins leads to an increase in succinate-mediated catabolite repression (SMCR). In order to explore the molecular determinants of HPr phosphorylation by EI(Ntr), both proteins were purified and the activity of EI(Ntr) was measured. Experimentally determined kinetic parameters of EI(Ntr) activity were significantly slower than those determined for the carbohydrate-type EI in Escherichia coli. Enzymatic assays showed that glutamine, a signal of nitrogen availability in many Gram-negative bacteria, strongly inhibits EI(Ntr). Binding experiments using the isolated GAF domain of EI(Ntr) (EIGAF) showed that it is the domain responsible for detection of glutamine. EI(Ntr) activity was not affected by α-ketoglutarate, and no binding between the EIGAF and α-ketoglutarate could be detected. These data suggest that in S. melilloti, EI(Ntr) phosphorylation of HPr is regulated by signals from both carbon metabolism (phosphoenolpyruvate) and nitrogen metabolism (glutamine).

  9. Irreversible sortase A-mediated ligation driven by diketopiperazine formation.

    Science.gov (United States)

    Liu, Fa; Luo, Ethan Y; Flora, David B; Mezo, Adam R

    2014-01-17

    Sortase A (SrtA)-mediated ligation has emerged as an attractive tool in bioorganic chemistry attributing to the remarkable specificity of the ligation reaction and the physiological reaction conditions. However, the reversible nature of this reaction limits the efficiency of the ligation reaction and has become a significant constraint to its more widespread use. We report herein a novel set of SrtA substrates (LPETGG-isoacyl-Ser and LPETGG-isoacyl-Hse) that can be irreversibly ligated to N-terminal Gly-containing moieties via the deactivation of the SrtA-excised peptide fragment through diketopiperazine (DKP) formation. The convenience of the synthetic procedure and the stability of the substrates in the ligation buffer suggest that both LPETGG-isoacyl-Ser and LPETGG-isoacyl-Hse are valuable alternatives to existing irreversible SrtA substrate sequences.

  10. Fractionation and characterization of polysaccharides from cyanobacterium Spirulina (Arthrospira) maxima in nitrogen-limited batch culture

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    By a sequentially selective extraction procedure, polysaccharides (PS) from cyanobacterium Spirulina (Arthrospira) maxima that can be bio-functionally healthy components were fractionated in four parts including the culture medium (PSCM), the external layers of the cell (PSEL), the cell wall (PSCW) and storage granules (PSSG). The four fractionated parts of polysaccharides were characterized by gas-liquid chromatography (GLC) equipped with FID and fused-silica capillary column (15 m×0.53 mm i. d.). The contents of PSCM, PSEL, PSCW and PSSG were about 2.0%, 2.6%, 10.0% and 52.0% to cell dry matter, respectively. Glucose was almost the only monosaccharide in PSSG and PSCW and most predominant in PSEL, while in PSCM, xylose, rhamnose and glucose were the main ones. Two uronic acids represented by glucuronic acid and galacturoic acid, six neutral monosaccharides including fucose, rhamnose, xylose, mannose, galactose and glucose, and two possible unidentified sugars were found in PSEL and PSCM. These data are valuable for the selective productions of high-added value sugars from Spirulina.

  11. Theoretical characterization of X-ray absorption, emission, and photoelectron spectra of nitrogen doped along graphene edges.

    Science.gov (United States)

    Wang, Xianlong; Hou, Zhufeng; Ikeda, Takashi; Oshima, Masaharu; Kakimoto, Masa-aki; Terakura, Kiyoyuki

    2013-01-24

    K-edge X-ray absorption (XAS), emission (XES), and photoelectron (XPS) spectra of nitrogen doped along graphene edges are systematically investigated by using first-principles methods. In this study we considered pyridinium-like, pyridine-like, cyanide-like, and amine-like nitrogens at armchair and zigzag edges and pyrrole-like nitrogen at armchair edge as well as graphite-like nitrogen at graphene interior site. Our results indicate that nitrogen configuration and its location (armchair or zigzag edge) in nitrogen-doped graphene can be identified via the spectral analysis. Furthermore, some controversial spectral features observed in experiment for N-doped graphene-like materials are unambiguously assigned. The present analysis gives an explanation to the reason why the peak assignment is usually made differently between XPS and XAS.

  12. Hexamine cobalt chloride promotes intermolecular ligation of blunt end DNA fragments by T4 DNA ligase.

    OpenAIRE

    Rusche, J R; Howard-Flanders, P

    1985-01-01

    Hexamine cobalt chloride (HCC) increases the efficiency of blunt end ligation by T4 DNA ligase about 50 fold. Maximum stimulation occurs when standard buffers for ligation are supplemented with 1 mM HCC. All the ligation events are intermolecular regardless of the initial DNA concentration. In the presence of monovalent cations (eg. 25 mM KCl) HCC still increases the extent of T4 catalyzed ligation but intramolecular ligation products are also formed. Therefore, intermolecular ligation can be...

  13. Enhanced nitrogen removal in a wastewater treatment process characterized by carbon source manipulation with biological adsorption and sludge hydrolysis.

    Science.gov (United States)

    Liu, Hongbo; Zhao, Fang; Mao, Boyang; Wen, Xianghua

    2012-06-01

    An innovative adsorption/nitrification/denitrification/sludge-hydrolysis wastewater treatment process (ENRS) characterized by carbon source manipulation with a biological adsorption unit and a sludge hydrolysis unit was developed to enhance nitrogen removal and reduce sludge production for municipal wastewater treatment. The system presented good performance in pollutants removal, yielding the effluent with average COD, NH(4)(+)-N, TN and TP of 48.5, 0.6, 13.2 and 1.0 mg/L, respectively. Sixty percent of the total carbon source in the influent was concentrated and separated by the quick adsorption of activated sludge, providing the possibilities of reusing waste carbon source in the denitrification tank and accumulating nitrobacteria in the nitrification tank. Low temperature of 6-15 °C and high hydraulic loading rate of 3.0-15.0 m(3)/d did not affect NH(4)(+)-N removal performance, yielding the NH(4)(+)-N of lower 1.0 mg/L in the effluent. Furthermore, 50% of the residual sludge in the ENRS system could be transformed into soluble COD (SCOD) by alkaline thermal hydrolysis with temperature of 60 °C and pH of 11, and the hydrolyzed carbon could completely substitute methanol as a good quality carbon to support high efficient denitrification.

  14. Small gold nanoparticles for interfacial Staudinger-Bertozzi ligation.

    Science.gov (United States)

    Gobbo, Pierangelo; Luo, Wilson; Cho, Sung Ju; Wang, Xiaoxiao; Biesinger, Mark C; Hudson, Robert H E; Workentin, Mark S

    2015-04-21

    Small gold nanoparticles (AuNPs) that possess interfacial methyl-2-(diphenylphosphino)benzoate moieties have been successfully synthesized (Staudinger-AuNPs) and characterized by multi-nuclear MR spectroscopy, transmission electron microscopy (TEM), UV-Vis spectroscopy, thermogravimetric analysis, and X-ray photoelectron spectroscopy (XPS). In particular, XPS was remarkably sensitive for characterization of the novel nanomaterial, and in furnishing proof of its interfacial reactivity. These Staudinger-AuNPs were found to be stable to the oxidation of the phosphine center. The reaction with benzyl azide in a Staudinger-Bertozzi ligation, as a model system, was investigated using (31)P NMR spectroscopy. This demonstrated that the interfacial reaction was clean and quantitative. To showcase the potential utility of these Staudinger-AuNPs in bioorganic chemistry, a AuNP bioconjugate was prepared by reacting the Staudinger-AuNPs with a novel azide-labeled CRGDK peptide. The CRGDK peptide could be covalently attached to the AuNP efficiently, chemoselectively, and with a high loading.

  15. Synthesis, characterization and antimicrobial activities of mixed ligand transition metal complexes with isatin monohydrazone Schiff base ligands and heterocyclic nitrogen base

    Science.gov (United States)

    Devi, Jai; Batra, Nisha

    2015-01-01

    Mixed ligand complexes of Co(II), Ni(II), Cu(II) and Zn(II) with various uninegative tridentate ligands derived from isatin monohydrazone with 2-hydroxynapthaldehyde/substituted salicylaldehyde and heterocyclic nitrogen base 8-hydroxyquinoline have been synthesized and characterized by elemental analysis, conductometric studies, magnetic susceptibility and spectroscopic techniques (IR, UV-VIS, NMR, mass and ESR). On the basis of these characterizations, it was revealed that Schiff base ligands existed as monobasic tridentate ONO bonded to metal ion through oxygen of carbonyl group, azomethine nitrogen and deprotonated hydroxyl oxygen and heterocyclic nitrogen base 8-hydroxyquinoline existed as monobasic bidentate ON bonded through oxygen of hydroxyl group and nitrogen of quinoline ring with octahedral or distorted octahedral geometry around metal ion. All the compounds have been tested in vitro against various pathogenic Gram positive bacteria, Gram negative bacteria and fungi using different concentrations (25, 50, 100, 200 μg/mL) of ligands and their complexes. Comparative study of antimicrobial activity of ligands, and their mixed complexes indicated that complexes exhibit enhanced activity as compared to free ligands and copper(II) Cu(LIV)(Q)ṡH2O complex was found to be most potent antimicrobial agent.

  16. ALIS-FLP: Amplified ligation selected fragment-length polymorphism method for microbial genotyping

    DEFF Research Database (Denmark)

    Brillowska-Dabrowska, A.; Wianecka, M.; Dabrowski, Slawomir;

    2008-01-01

    A DNA fingerprinting method known as ALIS-FLP (amplified ligation selected fragment-length polymorphism) has been developed for selective and specific amplification of restriction fragments from TspRI restriction endonuclease digested genomic DNA. The method is similar to AFLP, but differs in tha...... combining the advantages of the AFLP technique with a simple, rapid and cheap polymerase chain reaction product detection method.......A DNA fingerprinting method known as ALIS-FLP (amplified ligation selected fragment-length polymorphism) has been developed for selective and specific amplification of restriction fragments from TspRI restriction endonuclease digested genomic DNA. The method is similar to AFLP, but differs...... for differentiation of the organisms without previous knowledge of their DNA sequence. The usefulness of the method is confirmed by genotyping of 70 previously characterized clinical E. coli isolates. The grouping obtained was identical to the results of REA-PFGE. Versatility of the method is highlighted, i.e. its...

  17. Convergent synthesis of proteins by kinetically controlled ligation

    Science.gov (United States)

    Kent, Stephen; Pentelute, Brad; Bang, Duhee; Johnson, Erik; Durek, Thomas

    2010-03-09

    The present invention concerns methods and compositions for synthesizing a polypeptide using kinetically controlled reactions involving fragments of the polypeptide for a fully convergent process. In more specific embodiments, a ligation involves reacting a first peptide having a protected cysteyl group at its N-terminal and a phenylthioester at its C-terminal with a second peptide having a cysteine residue at its N-termini and a thioester at its C-termini to form a ligation product. Subsequent reactions may involve deprotecting the cysteyl group of the resulting ligation product and/or converting the thioester into a thiophenylester.

  18. Characterization of two naturally truncated, Ssb-like proteins from the nitrogen-fixing cyanobacterium, Anabaena sp. PCC7120.

    Science.gov (United States)

    Kirti, Anurag; Rajaram, Hema; Apte, Shree Kumar

    2013-11-01

    Single-stranded (ss) DNA-binding (Ssb) proteins are vital for all DNA metabolic processes and are characterized by an N-terminal OB-fold followed by P/G-rich spacer region and a C-terminal tail. In the genome of the heterocystous, nitrogen-fixing cyanobacterium, Anabaena sp. strain PCC 7120, two genes alr0088 and alr7579 are annotated as ssb, but the corresponding proteins have only the N-terminal OB-fold and no P/G-rich region or acidic tail, thereby rendering them unable to interact with genome maintenance proteins. Both the proteins were expressed under normal growth conditions in Anabaena PCC7120 and regulated differentially under abiotic stresses which induce DNA damage, indicating that these are functional genes. Constitutive overexpression of Alr0088 in Anabaena enhanced the tolerance to DNA-damaging stresses which caused formation of DNA adducts such as UV and MitomycinC, but significantly decreased the tolerance to γ-irradiation, which causes single- and double-stranded DNA breaks. On the other hand, overexpression of Alr7579 had no significant effect on normal growth or stress tolerance of Anabaena. Thus, of the two truncated Ssb-like proteins, Alr0088 may be involved in protection of ssDNA from damage, but due to the absence of acidic tail, it may not aid in repair of damaged DNA. These two proteins are present across cyanobacterial genera and unique to them. These initial studies pave the way to the understanding of DNA repair in cyanobacteria, which is not very well documented.

  19. Extended X-ray absorption fine structure studies of Zn2Fe2 hybrid hemoglobins: absence of heme bond length changes in half-ligated species.

    Science.gov (United States)

    Simolo, K; Korszun, Z R; Stucky, G; Moffat, K; McLendon, G; Bunker, G

    1986-07-01

    Metal hybrid hemoglobins, in which Zn(II) replaces Fe(II), have been structurally characterized by extended X-ray absorption structure (EXAFS) studies. Since Zn and Fe have very different K absorption edge energies, the structures of the ligated (Fe) and unligated (Zn) sites could be examined independently within a single molecule that mimics an intermediate ligation state. The observed EXAFS spectra and associated structural parameters are compared among the ligand free (alpha Zn)2(beta Zn)2, half-ligated (alpha FeCO)2(beta Zn)2 and (alpha Zn)2(beta FeCO)2, and fully ligated (alpha FeCO)2(beta FeCO)2 systems.

  20. Isolation and characterization of a bacterium which utilizes polyester polyurethane as a sole carbon and nitrogen source.

    Science.gov (United States)

    Nakajima-Kambe, T; Onuma, F; Kimpara, N; Nakahara, T

    1995-06-01

    Various soil samples were screened for the presence of microorganisms which have the ability to degrade polyurethane compounds. Two strains with good polyurethane degrading activity were isolated. The more active strain was tentatively identified as Comamonas acidovorans. This strain could utilize polyester-type polyurethanes but not the polyether-type polyurethanes as sole carbon and nitrogen sources. Adipic acid and diethylene glycol were probably the main degradation products when polyurethane was supplied as a sole carbon and nitrogen source. When ammonium nitrate was used as nitrogen source, only diethylene glycol was detected after growth on polyurethane.

  1. Characterization of Changes in Gluten Proteins in Low-Gliadin Transgenic Wheat Lines in Response to Application of Different Nitrogen Regimes

    Science.gov (United States)

    García-Molina, María Dolores; Barro, Francisco

    2017-01-01

    Gluten proteins are major determinants of the bread making quality of wheat but also of important gluten-related disorders. The gluten protein accumulation during grain filling is strongly influenced by nitrogen fertilization. We have characterized the gluten proteins in low-gliadin wheat lines as influenced by nitrogen treatments in two experiments. These transgenic lines, D783, D793, C655, D577, and E82 were obtained by using two different RNAi silencing fragments and two endosperm-specific promoters to drive the silencing fragments (d-hordein and γ-gliadin). In Experiment 1, we used three nitrogen fertilizer rates (120, 360, and 1080 mg N) added at sowing stage and combined with two sulfur rates (8 and 30 mg S); Experiment 2 included two nitrogen levels (120 and 1080 mg N), which were added according to the greatest demand per plant using split applications. The protein quantification was accomplished by Reverse-Phase High-Performance Liquid Chromatography and gluten content (ppm) determined using monoclonal antibody R5 (Competitive R5 ELISA). The results showed differences in protein accumulation between the two transgenic lines with the same silencing fragment but different promoter. Lines D793 and E82 showed low gliadin and an increment in glutenin content with increasing nitrogen. Competitive ELISA R5 showed a significant decrease in gluten content using split applications of nitrogen (Experiment 2) with 120 mg N compared to Experiment 1. In addition, line E82 ensures that variations in N fertilization will not result in increased gluten content. PMID:28289425

  2. Formatting and ligating biopolymers using adjustable nanoconfinement

    Science.gov (United States)

    Berard, Daniel J.; Shayegan, Marjan; Michaud, Francois; Henkin, Gil; Scott, Shane; Leslie, Sabrina

    2016-07-01

    Sensitive visualization and conformational control of long, delicate biopolymers present critical challenges to emerging biotechnologies and biophysical studies. Next-generation nanofluidic manipulation platforms strive to maintain the structural integrity of genomic DNA prior to analysis but can face challenges in device clogging, molecular breakage, and single-label detection. We address these challenges by integrating the Convex Lens-induced Confinement (CLiC) technique with a suite of nanotopographies embedded within thin-glass nanofluidic chambers. We gently load DNA polymers into open-face nanogrooves in linear, concentric circular, and ring array formats and perform imaging with single-fluorophore sensitivity. We use ring-shaped nanogrooves to access and visualize confinement-enhanced self-ligation of long DNA polymers. We use concentric circular nanogrooves to enable hour-long observations of polymers at constant confinement in a geometry which eliminates the confinement gradient which causes drift and can alter molecular conformations and interactions. Taken together, this work opens doors to myriad biophysical studies and biotechnologies which operate on the nanoscale.

  3. A comparative study of Barron's rubber band ligation with Kshar Sutra ligation in hemorrhoids

    Science.gov (United States)

    Singh, Rakhi; Arya, Ramesh C.; Minhas, Satinder S.; Dutt, Anil

    2010-01-01

    Despite a long medical history of identification and treatment, hemorrhoids still pose a challenge to the medical fraternity in terms of finding satisfactory cure of the disease. In this study, Kshar Sutra Ligation (KSL), a modality of treatment described in Ayurveda, was compared with Barron's Rubber Band Ligation (RBL) for grade II and grade III hemorrhoids. This study was conducted in 20 adult patients of either sex with grade II and grade III hemorrhoids at two different hospitals. Patients were randomly allotted to two groups of 10 patients each. Group I patients underwent RBL, whereas patients of group II underwent KSL. Guggul-based Apamarga Kshar Sutra was prepared according to the principles laid down in ancient Ayurvedic texts and methodology standardized by IIIM, Jammu and CDRI, Lucknow. Comparative assessment of RBL and KSL was done according to 16 criteria. Although the two procedures were compared on 15 criteria, treatment outcome of grade II and grade III hemorrhoids was decided chiefly on the basis of patient satisfaction index (subjective criterion) and ability of each procedure to deal with prolapse of internal hemorrhoidal masses (objective criterion): Findings in each case were recorded over a follow-up of four weeks (postoperative days 1, 3, 7, 15 and 30). Statistical analysis was done using Student's t test for parametric data and Chi square test & Mann-Whitney test for non-parametric data. P 0.05). Both the groups were comparable statistically on all other grounds. Kshar Sutra Ligation is a useful form of treatment for Grades II and III internal hemorrhoids. PMID:20814519

  4. A Photo-Triggered Traceless Staudinger-Bertozzi Ligation Reaction.

    Science.gov (United States)

    Hu, Peng; Feng, Tianshi; Yeung, Chi-Chung; Koo, Chi-Kin; Lau, Kai-Chung; Lam, Michael H W

    2016-08-08

    The use of light to control the course of a chemical/biochemical reaction is an attractive idea because of its ease of administration with high precision and fine spatial resolution. Staudinger ligation is one of the commonly adopted conjugation processes that involve a spontaneous reaction between azides and arylphosphines to form iminophosphoranes, which further hydrolyze to give stable amides. We designed an anthracenylmethyl diphenylphosphinothioester (1) that showed promising Staudinger ligation reactivity upon photo-excitation. Broadband photolysis at 360-400 nm in aqueous organic solvents induced heterolytic cleavage of its anthracenylmethyl-phosphorus bond, releasing a diphenylphosphinothioester (2) as an efficient traceless Staudinger-Bertozzi ligation reagent. The quantum yield of such a photo-induced heterolytic bond-cleavage at the optimal wavelength of photolysis (376 nm) at room temperature is ≥0.07. This work demonstrated the feasibility of photocaging arylphosphines to realize the photo-triggering of the Staudinger ligation reaction.

  5. Characterization of thin Ta-Si-N {sub x} layers of different nitrogen content using XPS, UPS and STM

    Energy Technology Data Exchange (ETDEWEB)

    Zahn, W. [University of Applied Science Zwickau, Dr.-Friedrichs-Ring 2A, D-08056 Zwickau (Germany)]. E-mail: wieland.zahn@fh-zwickau.de; Hildebrand, D. [University of Applied Science Zwickau, Dr.-Friedrichs-Ring 2A, D-08056 Zwickau (Germany); Menzel, S. [Leibniz Institute for Solid State and Materials Research (IFW) Dresden, P.O. Box 270116, D-01171 Dresden (Germany); Oswald, S. [Leibniz Institute for Solid State and Materials Research (IFW) Dresden, P.O. Box 270116, D-01171 Dresden (Germany); Heuer, H. [Dresden University of Technology, D-01062 Dresden (Germany)

    2005-09-30

    Reactively sputtered Ta-Si-N {sub x} barrier systems of different nitrogen content on copper were investigated by photoelectron spectroscopy (XPS, UPS) and scanning tunnelling microscopy (STM). The measured photoelectron spectra (excitation He-I) showed a clear dependence of the electron state density near the Fermi edge on the content of nitrogen. These results correlate with the I(U) characteristics of the STM measurements and the electrical conductivity of these layers.

  6. RNA-templated DNA ligation for transcript analysis

    OpenAIRE

    Nilsson, Mats; Antson, Dan-Oscar; Barbany, Gisela; Landegren, Ulf

    2001-01-01

    Ligase-mediated gene detection has proven valuable for detection and precise distinction of DNA sequence variants. We have recently shown that T4 DNA ligase can also be used to distinguish single nucleotide variants of RNA sequences. Here we describe parameters that influence RNA-templated DNA ligation by T4 DNA ligase. The reaction proceeds much more slowly, requiring more enzyme, compared to ligation of the same oligonucleotides hybridized to the corresponding DNA se...

  7. Intramyocardial activation in early ventricular arrhythmias following coronary artery ligation.

    Science.gov (United States)

    Kaplinsky, E; Ogawa, S; Kmetzo, J; Balke, C W; Dreifus, L S

    1980-01-01

    Subendocardial, subepicardial and intramyocardial activation in the ischemic zone was investigated in 20 anesthetized open chest dogs 0-30 minutes after the ligation of the left anterior descending coronary artery. Single and composite electrograms and lead 2 of the ECG were recorded. Coronary artery ligation produced marked delay, fragmentation, and reduction in amplitude in the electrical activity of the subepicardial and intramyocardial muscle layers. The activation remained synchronous in the subendocardial muscle layers. Extension of electrical activity in the ischemic subepicardium and intramyocardium beyond the T wave of the surface ECG preceded the onset of immediate ventricular arrhythmias (IVA) during the initial ten minute period after coronary artery ligation. However, a second surge of delayed ventricular arrhythmias (DVA), 10-30 minutes after ligation, was not associated with the appearance of diastolic electrical activity in any of the subepicardial or myocardial layers. It appears that subepicardial as well as intramyocardial reentry could play an important role in the genesis of the immediate ventricular arrhythmias (1-10 minutes after ligation). In contrast, no obvious reentrant activity as evidenced by delayed and fragmented electrical activity could be observed in the electrogram from any of the myocardial electrical activity could be observed in the electrogram from any of the myocardial layers with the appearance of delayed ventricular ectopic activity 10-30 minutes after ligation.

  8. Rubber band ligation of hemorrhoids: A guide for complications

    Science.gov (United States)

    Albuquerque, Andreia

    2016-01-01

    Rubber band ligation is one of the most important, cost-effective and commonly used treatments for internal hemorrhoids. Different technical approaches were developed mainly to improve efficacy and safety. The technique can be employed using an endoscope with forward-view or retroflexion or without an endoscope, using a suction elastic band ligator or a forceps ligator. Single or multiple ligations can be performed in a single session. Local anaesthetic after ligation can also be used to reduce the post-procedure pain. Mild bleeding, pain, vaso-vagal symptoms, slippage of bands, priapism, difficulty in urination, anal fissure, and chronic longitudinal ulcers are normally considered minor complications, more frequently encountered. Massive bleeding, thrombosed hemorrhoids, severe pain, urinary retention needing catheterization, pelvic sepsis and death are uncommon major complications. Mild pain after rubber band ligation is the most common complication with a high frequency in some studies. Secondary bleeding normally occurs 10 to 14 d after banding and patients taking anti-platelet and/or anti-coagulant medication have a higher risk, with some reports of massive life-threatening haemorrhage. Several infectious complications have also been reported including pelvic sepsis, Fournier’s gangrene, liver abscesses, tetanus and bacterial endocarditis. To date, seven deaths due to these infectious complications were described. Early recognition and immediate treatment of complications are fundamental for a favourable prognosis. PMID:27721924

  9. Mechanism of Imidazole-Promoted Ligation of Peptide Phenyl Esters

    Institute of Scientific and Technical Information of China (English)

    王晨; 刘磊

    2012-01-01

    Imidazole-promoted ligation of peptide phenyl esters was recently found to be a complementary method for protein chemical synthesis. Theoretical calculations have been carried out to understand the detailed mechanism of this particular ligation process. It is found that both the reaction of the phenyl ester with imidazole and the reaction of the acyl imidazole intermediate with cysteine proceed through an addition-elimination mechanism. The cleavage of the C--O bond in the reaction between the phenyl ester and imidazole is the rate-limiting step of the overall liga- tion process. Interestingly, although the imidazole-promoted phenyl ester ligation has a higher free energy barrier than the conventional thiophenol-promoted native chemical ligation for a sterically less hindered C-terminal amino acid (e.g. gylcine), for a sterically hindered C-terminal amino acid (e.g. proline) the imidazole-promoted phenyl ester ligation is calculated to be more favorable than the conventional thiophenol-promoted native chemical ligation.

  10. DNA strand transfer catalyzed by vaccinia topoisomerase: ligation of DNAs containing a 3' mononucleotide overhang.

    Science.gov (United States)

    Cheng, C; Shuman, S

    2000-05-01

    The specificity of vaccinia topoisomerase for transesterification to DNA at the sequence 5'-CCCTT and its versatility in strand transfer have illuminated the recombinogenic properties of type IB topoisomerases and spawned topoisomerase-based strategies for DNA cloning. Here we characterize a pathway of topoisomerase-mediated DNA ligation in which enzyme bound covalently to a CCCTT end with an unpaired +1T nucleotide rapidly and efficiently joins the CCCTT strand to a duplex DNA containing a 3' A overhang. The joining reaction occurs with high efficiency, albeit slowly, to duplex DNAs containing 3' G, T or C overhangs. Strand transfer can be restricted to the correctly paired 3' A overhang by including 0.5 M NaCl in the ligation reaction mixture. The effects of base mismatches and increased ionic strength on the rates of 3' overhang ligation provide a quantitative picture of the relative contributions of +1 T:A base pairing and electrostatic interactions downstream of the scissile phosphate to the productive binding of an unlinked acceptor DNA to the active site. The results clarify the biochemistry underlying topoisomerase-cloning of PCR products with non-templated 3' overhangs.

  11. Lipid Raft is required for PSGL-1 ligation induced HL-60 cell adhesion on ICAM-1.

    Directory of Open Access Journals (Sweden)

    Tingshuang Xu

    Full Text Available P-selectin glycoprotein ligand-1 (PSGL-1 and integrins are adhesion molecules that play critical roles in host defense and innate immunity. PSGL-1 mediates leukocyte rolling and primes leukocytes for integrin-mediated adhesion. However, the mechanism that PSGL-1 as a rolling receptor in regulating integrin activation has not been well characterized. Here, we investigate the function of lipid raft in regulating PSGL-1 induced β2 integrin-mediated HL-60 cells adhesion. PSGL-1 ligation with antibody enhances the β2 integrin activation and β2 integrin-dependent adhesion to ICAM-1. Importantly, with the treatment of methyl-β-cyclodextrin (MβCD, we confirm the role of lipid raft in regulating the activation of β2 integrin. Furthermore, we find that the protein level of PSGL-1 decreased in raft fractions in MβCD treated cells. PSGL-1 ligation induces the recruitment of spleen tyrosine kinase (Syk, a tyrosine kinase and Vav1 (the pivotal downstream effector of Syk signaling pathway involved in cytoskeleton regulation to lipid raft. Inhibition of Syk activity with pharmacologic inhibitor strongly reduces HL-60 cells adhesion, implicating Syk is crucial for PSGL-1 mediated β2 integrin activation. Taken together, we report that ligation of PSGL-1 on HL-60 cells activates β2 integrin, for which lipid raft integrity and Syk activation are responsible. These findings have shed new light on the mechanisms that connect leukocyte initial rolling with subsequent adhesion.

  12. Producing peptide arrays for epitope mapping by intein-mediated protein ligation.

    Science.gov (United States)

    Sun, Luo; Rush, John; Ghosh, Inca; Maunus, Jeremy R; Xu, Ming-Qun

    2004-09-01

    Peptide arrays are increasingly used to define antibody epitopes and substrate specificities of protein kinases. Their use is hampered, however, by ineffective and variable binding efficiency of peptides, which often results in low sensitivity and inconsistent results. To overcome these limitations, we have developed a novel method for making arrays of synthetic peptides on various membranes after ligating the peptide substrates to an intein-generated carrier protein. We have conducted screening for optimal carrier proteins by immunoreactivity and direct assessment of binding using a peptide derivatized at a lysine sidechain with fluorescein, CDPEK(fluorescein)DS. Ligation of a synthetic peptide antigen to a carrier protein, HhaI methylase, resulted in an improved retention of peptides and an increased sensitivity of up to 10(4)-fold in immunoassay- and epitope-scanning experiments. Denaturing the ligation products with 2% sodium dodecyl sulfate (SDS) or an organic solvent (20% methanol) prior to arraying did not significantly affect the immunoreactivity of the HhaI methylase-peptide product. Because the carrier protein dominates the binding of ligation products and contains one peptide reactive site, the amount of peptide arrayed onto the membranes can be effectively normalized. This technique was utilized in the alanine scanning of hemagglutinin (HA) antigen using two monoclonal antibodies, resulting in distinguishing the different antigen epitope profiles. Furthermore, we show that this method can be used to characterize the antibodies that recognize phosphorylated peptides. This novel approach allows for synthetic peptides to be uniformly arrayed onto membranes, compatible with a variety of applications.

  13. Precise sequential DNA ligation on a solid substrate: solid-based rapid sequential ligation of multiple DNA molecules.

    Science.gov (United States)

    Takita, Eiji; Kohda, Katsunori; Tomatsu, Hajime; Hanano, Shigeru; Moriya, Kanami; Hosouchi, Tsutomu; Sakurai, Nozomu; Suzuki, Hideyuki; Shinmyo, Atsuhiko; Shibata, Daisuke

    2013-12-01

    Ligation, the joining of DNA fragments, is a fundamental procedure in molecular cloning and is indispensable to the production of genetically modified organisms that can be used for basic research, the applied biosciences, or both. Given that many genes cooperate in various pathways, incorporating multiple gene cassettes in tandem in a transgenic DNA construct for the purpose of genetic modification is often necessary when generating organisms that produce multiple foreign gene products. Here, we describe a novel method, designated PRESSO (precise sequential DNA ligation on a solid substrate), for the tandem ligation of multiple DNA fragments. We amplified donor DNA fragments with non-palindromic ends, and ligated the fragment to acceptor DNA fragments on solid beads. After the final donor DNA fragments, which included vector sequences, were joined to the construct that contained the array of fragments, the ligation product (the construct) was thereby released from the beads via digestion with a rare-cut meganuclease; the freed linear construct was circularized via an intra-molecular ligation. PRESSO allowed us to rapidly and efficiently join multiple genes in an optimized order and orientation. This method can overcome many technical challenges in functional genomics during the post-sequencing generation.

  14. PHYSIOLOGICAL MENSTRUAL RHYTHM AND FERTILITY AFTER INTERNAL ILIAC ARTERY LIGATION

    Directory of Open Access Journals (Sweden)

    Sunaina

    2015-11-01

    Full Text Available AIMS AND OBJECTIVE Bilateral internal iliac artery ligation is a useful skill for the management of life-threatening post-partum hemorrhage. The procedure is not without risks and long-term complications. This study was conducted to ensure documentation and reporting of pregnancies following bilateral hypogastric artery ligation in cases of post-partum hemorrhage. We also aimed to compare the menstrual function and reproductive outcome after bilateral internal iliac artery ligation done for atonic post-partum haemorrhage. DESIGN Prospective Case Study. SETTING Department of Obstetrics and Gynaecology, Institute of Obstetrics and Gynaecology, Madras Medical College and Hospital, Chennai, Jan 2013 to March 2015. PARTICIPANTS Ten cases of bilateral internal iliac artery ligation were done for atonic post-partum hemorrhage. Main outcome measures: The primary outcome was assessed as the resumption of menstruation, regular cycles, and ability to conceive after surgery. Secondary outcome was incidence of intrauterine growth retardation and recurrent post-partum hemorrhage in subsequent pregnancies. RESULTS The mean duration of resumption of menstruation following internal iliac artery ligation was 3 months. Bilateral internal iliac artery ligation is preferred over unilateral ligation as the extensive collaterals from the contralateral side immediately fill the circulation. The cases of atonic post-partum hemorrhage may require B-Lynch sutures in addition to bilateral internal iliac artery ligation to regain tone. Successful pregnancy after bilateral internal iliac artery ligation occurred in three out of seven cases. In one case, there was intrauterine growth retardation in eighth month. The patient was admitted and closely monitored with Doppler scan. At 35 weeks of gestation, emergency lower segment caesarean section was done for absent diastolic flow. The preterm neonate was 2 kilograms. There was no post-partum hemorrhage in the subsequent

  15. Preparation and characterization of (metal, nitrogen)-codoped TiO2 by TiCl4 sol-gel auto-igniting synthesis

    Institute of Scientific and Technical Information of China (English)

    LIU Zhongqing; ZHOU Yanping; LI Zhenhua; WANG Yichao; GE Changchun

    2007-01-01

    The nitrogen-doped and (metal, nitrogen)-codoped TiO2 photocatalysts (metal = Ag, Ce, Fe, La) were synthesized by sol-gel auto-igniting synthesis (SAS) with the complex compound sol of TiCl4-NH4NO3-citri acid-metal nitrateNH3.H2O as a precursor. The products were characterized by means of XRD, XPS, and UV-Vis diffuse reflectance spectra,and their photocatalytic activity was investigated under visible light. It was found that all the synthesized powders showed good absorption for visible light, and that the radius and alterable valence states of doping metallic cations played important roles on their photocatalytic activity. These results were discussed in detail.

  16. Synthesis, characterization and photo catalytic activity of titanium oxide modified with nitrogen; Sintesis, caracterizacion y actividad fotocatalitica de oxido de titanio modificado con nitrogeno

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez Enriquez, J. M.; Garcia Alamilla, R.; Garcia Serrano, L. A.; Cueto Hernandez, A.

    2011-07-01

    Titanium oxides (TiO{sub 2}) were synthesized by precipitation of titanium tetrachloride (TiCl{sub 4}) using ammonium hydroxide (NH{sub 4}OH). The synthesized materials were characterized by means of nitrogen physisorption, X-ray diffraction, infrared spectroscopy, U.V.-visible diffuse reflectance spectroscopy and the photo catalytic activity of the samples were measured by the degradation of the methyl orange. By means of this synthesis method we have doped the titanium oxide structure with nitrogen (N-TiO{sub 2}), stabilizing the anatase phase and obtaining meso porous and nanocrystalline materials. The titanium oxide with higher specific surface area (132 m{sup 2}/g) degraded the azo-compound to 100% in 180 min of reaction. (Author) 33 refs.

  17. A study of parameter setting and characterization of visible-light driven nitrogen-modified commercial TiO{sub 2} photocatalysts

    Energy Technology Data Exchange (ETDEWEB)

    Kuo, Yu-Lin, E-mail: ylkuo@mail.ntust.edu.tw [Department of Mechanical Engineering, National Taiwan University of Science and Technology, No. 43, Sec. 4, Keelung Rd., Taipei 106, Taiwan (China); Su, Te-Li [Department of Cosmetic Application and Management, St. Mary' s Medicine, Nursing and Management College, Yilan 266, Taiwan (China); Kung, Fu-Chen [Department of Health Developing and Health Marketing, Kainan University, Taoyuan County 338, Taiwan (China); Wu, Tsai-Jung [Department of Mechanical Engineering, National Taiwan University of Science and Technology, No. 43, Sec. 4, Keelung Rd., Taipei 106, Taiwan (China)

    2011-06-15

    Highlights: {yields} A cost-effective and highly-efficient visible-light driven nitrogen-modified TiO{sub 2} photocatalyst was prepared by a simple hydrolysis method. {yields} The obtained optimum conditions applied to Taguchi method for preparing visible-light driven photocatalyst were undergone by the process of stirring for 1 day using 4M ammonium as the nitrogen source, and then calcining at 400{sup Degree-Sign }C for 2 h. {yields} Several materials technologies of characterizing N-TiO2 photocatalyst have been used to realize the modification of TiO2 by ammonia water as the nitrogen source. - Abstract: An optimal condition applied to the Taguchi method with an L{sub 9} orthogonal array for preparing a visible-light driven nitrogen-modified TiO{sub 2} (N-TiO{sub 2}) photocatalyst by a simple hydrolysis method has been examined for material characteristics and a photodecolorization test of methyl blue (MB) under various visible light source (fluorescent and blue LED lamps) irradiations. Results of the material characterization showed that the absorption of prepared N-TiO{sub 2} powder exhibited a significant extension into visible light regimes with an optical bandgap (Eg) of around 2.96 eV, which subsequently improved the visible-light photocatalytic activity of N-TiO{sub 2} samples. The superior photocatalytic properties, the pseudo first-order reaction rate constants (k) and photodecolorization efficiency ({eta}%) of a N-TiO{sub 2} photocatalyst during the photodecolorization test of methyl blue (MB) under two different visible light irradiations were very evident compared to those for pure TiO{sub 2}. For photodecolorization of practical dyeing from the waste water from the dyeing and finishing industry, a higher photodecolorization efficiency of N-TiO{sub 2} powder toward Direct blue-86 (DB-86) (Direct Fast Turquoise Blue GL) dye was also achieved.

  18. Synthesis of phosphine and antibody-azide probes for in vivo Staudinger ligation in a pretargeted imaging and therapy approach.

    Science.gov (United States)

    Vugts, Danielle J; Vervoort, Annelies; Stigter-van Walsum, Marijke; Visser, Gerard W M; Robillard, Marc S; Versteegen, Ron M; Vulders, Roland C M; Herscheid, J Koos D M; van Dongen, Guus A M S

    2011-10-19

    The application of intact monoclonal antibodies (mAbs) as targeting agents in nuclear imaging and radioimmunotherapy is hampered by the slow pharmacokinetics of these molecules. Pretargeting with mAbs could be beneficial to reduce the radiation burden to the patient, while using the excellent targeting capacity of the mAbs. In this study, we evaluated the applicability of the Staudinger ligation as pretargeting strategy using an antibody-azide conjugate as tumor-targeting molecule in combination with a small phosphine-containing imaging/therapeutic probe. Up to 8 triazide molecules were attached to the antibody without seriously affecting its immunoreactivity, pharmacokinetics, and tumor uptake in tumor bearing nude mice. In addition, two (89)Zr- and (67/68)Ga-labeled desferrioxamine (DFO)-phosphines, a (177)Lu-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA)-phosphine and a (123)I-cubyl phosphine probe were synthesized and characterized for their pharmacokinetic behavior in nude mice. With respect to the phosphine probes, blood levels at 30 min after injection were phosphine, relative to the azide, in aqueous solution resulted in 20-25% efficiency after 2 h. The presence of 37% human serum resulted in a reduced ligation efficiency (reduction max. 30% at 2 h), while the phosphines were still >80% intact. No in vivo Staudinger ligation was observed in a mouse model after injection of 500 μg antibody-azide, followed by 68 μg DFO-phosphine at t = 2 h, and evaluation in blood at t = 7 h. To explain negative results in mice, Staudinger ligation was performed in vitro in mouse serum. Under these conditions, a side product with the phosphine was formed and ligation efficiency was severely reduced. It is concluded that in vivo application of the Staudinger ligation in a pretargeting approach in mice is not feasible, since this ligation reaction is not bioorthogonal and efficient enough. Slow reaction kinetics will also severely restrict the applicability

  19. Clinical application of a ligation-independent pathway of multiplex ligation-dependent probe amplification for the determination of quinolone susceptibility of Streptococcus pneumoniae.

    Science.gov (United States)

    Uno, Naoki; Araki, Nobuko; Kaku, Norihito; Kosai, Kosuke; Hasegawa, Hiroo; Yanagihara, Katsunori

    2016-09-01

    We previously uncovered a ligation-independent pathway of multiplex ligation-dependent probe amplification (MLPA) through which products of MLPA could be amplified without both hybridization and ligation reactions. Here, we utilized this pathway to detect an antibiotic resistance mutation of quinolones in Streptococcus pneumoniae.

  20. 氮掺杂石墨烯凝胶的制备与表征%Preparation and Characterization of Nitrogen-Doped Grapheme Hydrogel

    Institute of Scientific and Technical Information of China (English)

    2016-01-01

    For the future application of graphene hydrogel in supercapacitors, nitrogen-doped grapheme hydro?gels were prepared by the hydrothermal method using ammonia and hydrazine hydrate as the reducing agent and nitrogen resource, respectively. X-ray photoelectron spectroscopy, elemental analysis and scanning electron microscope were carried out to characterize the structure and morphology of the nitrogen-doped graphene hydro?gel. Moreover, the electrochemical performance was measured by cyclic voltammetry and galvanostatic charge/discharge. The result shows that when nitrogen-containing agents are added during the hydrothermal process of graphene oxide, the nitrogen-doped graphene hydrogel with three-dimension porous structure and certain mechanical strength can be obtained. The specific capacitance of nitrogen-doped graphene hydrogel also increases because of nitrogen-doping. The specific capacitance of nitrogen-doped graphene hydrogel is 196 F/g and 217 F/g at the scanning rate of 10 mV/s and current density of 1 A/g, respectively. The specific capacitance of nitrogen-doped graphene hydrogel can keep 80% after 1000 cycles of cyclic voltammetry. It indicates that nitrogen-doped graphene hydrogel has good electrochemical properties for the application of supercapacitor electrode in future.%为了拓展石墨烯凝胶在超级电容器方面的应用,采用氨水、水合肼作为还原剂和掺杂剂,通过与氧化石墨烯的水热反应制备了氮掺杂石墨烯凝胶,并采用X射线光电子能谱,元素分析、扫描电子显微镜对产物的结构与微观形貌进行表征,采用循环伏安法和计时电位法测试其电化学性能.结果表明,在氧化石墨烯的水热反应体系中引入氮掺杂剂,不仅能得到具有三维多孔结构的有一定力学强度的凝胶,而且经过氮掺杂后石墨烯的电化学性能较纯石墨烯的有明显提高.当扫描速率为10 mV/s时,氮掺杂石墨烯的比电容为196 F/g;当电流密度为1 A/g

  1. Characterization of the start-up period of single-step autotrophic nitrogen removal in a sequencing batch reactor

    Institute of Scientific and Technical Information of China (English)

    GUO Jin-song; QIN Yu; FANG Fang; YANG Guo-hong

    2008-01-01

    The characteristics of the start-up period of single-step autotrophic nitrogen removal process were investigated. The autotrophic nitrogen removal process used a sequencing batch reactor to treat wastewater of medium to low ammonia-nitrogen concentration, with dissolved oxygen (DO), hydraulic retention time (HRT) and temperature controlled. The experimental conditions were temperature at (30(2) (C, ammonia concentration of (60 to 120) mg/L, DO of (0.8 to 1.0) mg/L, pH from 7.8 to 8.5 and HRT of 24 h. The rates of nitrification and nitrogen removal turn out to be 77% and 40%, respectively, after a start up period going through three stages divided according to nitrite accumulation: sludge domestication, nitrifying bacteria selection and sludge adaptation. It is demonstrated that dissolved oxygen is critical to nitrite accumulation and elastic YJZH soft compound packing is superior to polyhedral hollow balls in helping the bacteria adhere to the membrane.

  2. Chemical characterization of manure in relation to manure quality as a contribution to a reduced nitrogen emission to the environment

    NARCIS (Netherlands)

    Stelt, van der B.

    2007-01-01

    Keywords:manure composition, ammonia volatilization, free ions, Donnan Membrane Technique, manure additives, dietary changes, nitrogen dynamics,grasslandsoils.More insight in manure composition, ammonia (NH 3 ) volatilizatio

  3. Efficient in situ detection of mRNAs using the Chlorella virus DNA ligase for padlock probe ligation.

    Science.gov (United States)

    Schneider, Nils; Meier, Matthias

    2017-02-01

    Padlock probes are single-stranded DNA molecules that are circularized upon hybridization to their target sequence by a DNA ligase. In the following, the circulated padlock probes are amplified and detected with fluorescently labeled probes complementary to the amplification product. The hallmark of padlock probe assays is a high detection specificity gained by the ligation reaction. Concomitantly, the ligation reaction is the largest drawback for a quantitative in situ detection of mRNAs due to the low affinities of common DNA or RNA ligases to RNA-DNA duplex strands. Therefore, current protocols require that mRNAs be reverse transcribed to DNA before detection with padlock probes. Recently, it was found that the DNA ligase from Paramecium bursaria Chlorella virus 1 (PBCV-1) is able to efficiently ligate RNA-splinted DNA. Hence, we designed a padlock probe assay for direct in situ detection of mRNAs using the PBCV-1 DNA ligase. Experimental single-cell data were used to optimize and characterize the efficiency of mRNA detection with padlock probes. Our results demonstrate that the PBCV-1 DNA ligase overcomes the efficiency limitation of current protocols for direct in situ mRNA detection, making the PBCV-1 DNA ligase an attractive tool to simplify in situ ligation sequencing applications.

  4. Microwave-assisted synthesis, characterization and biological screening of nitrogen-sulphur and nitrogen-oxygen donor ligands and their organotin(IV) complexes.

    Science.gov (United States)

    Singh, R V; Chaudhary, Pratibha; Poonia, Kavita; Chauhan, Shikha

    2008-08-01

    Series of new trigonal bipyramidal and octahedral complexes of tin(IV) have been synthesized by the reaction of dimethyltin(IV) dichloride with 4-nitro-benzanilidethiosemicarbazone (L(1)H), 4-chlorobenzanilidethiosemicarbazone (L(2)H), 4-nitrobenzanilidesemicarbazone (L(3)H) and 4-chlorobenzanilidesemicarbazone (L(4)H). The unimolecular and bimolecular reactions of dimethyltin(IV) dichloride and monobasic bidentate ligands were carried out using microwave irradiations as the thermal energy source and the complexes so formed were characterized by elemental analysis, conductance measurements, molecular weight determinations and spectral data, viz. IR, UV-vis, (1)H and (13)C NMR. The complexes have also been prepared by the general thermal methods for comparison purposes. The comparison data support the synthesis using the microwave route, i.e. green chemistry route. The tin(IV) complexes show penta-coordinated structure for 1:1 complexes and hexa-coordinated for 1:2 complexes. The antifungal, antibacterial and antifertility activities have been examined and the results were indeed very encouraging.

  5. A Generic Polymer-Protein Ligation Strategy for Vaccine Delivery.

    Science.gov (United States)

    Lybaert, Lien; Vanparijs, Nane; Fierens, Kaat; Schuijs, Martijn; Nuhn, Lutz; Lambrecht, Bart N; De Geest, Bruno G

    2016-03-14

    Although the field of cancer immunotherapy is intensively investigated, there is still a need for generic strategies that allow easy, mild and efficient formulation of vaccine antigens. Here we report on a generic polymer-protein ligation strategy to formulate protein antigens into reversible polymeric conjugates for enhanced uptake by dendritic cells and presentation to CD8 T-cells. A N-hydroxypropylmethacrylamide (HPMA)-based copolymer was synthesized via RAFT polymerization followed by introduction of pyridyldisulfide moieties. To enhance ligation efficiency to ovalbumin, which is used as a model protein antigen, protected thiols were introduced onto lysine residues and deprotected in situ in the presence of the polymer. The ligation efficiency was compared for both the thiol-modified versus unmodified ovalbumin, and the reversibility was confirmed. Furthermore, the obtained nanoconjugates were tested in vitro for their interaction and association with dendritic cells, showing enhanced cellular uptake and antigen cross-presentation to CD8 T-cells.

  6. Template-Directed Ligation of Peptides to Oligonucleotides

    Science.gov (United States)

    Bruick, Richard K.; Dawson, Philip E.; Kent, Stephen BH; Usman, Nassim; Joyce, Gerald F.

    1996-01-01

    Synthetic oligonucleotides and peptides have enjoyed a wide range of applications in both biology and chemistry. As a consequence, oligonucleotide-peptide conjugates have received considerable attention, most notably in the development of antisense constructs with improved pharmacological properties. In addition, oligonucleotide-peptide conjugates have been used as molecular tags, in the assembly of supramolecular arrays and in the construction of encoded combinatorial libraries. To make these chimeric molecules more accessible for a broad range of investigations, we sought to develop a facile method for joining fully deprotected oligonucleotides and peptides through a stable amide bond linkage. Furthermore, we wished to make this ligation reaction addressable, enabling one to direct the ligation of specific oligonucleotide and peptide components.To confer specificity and accelerate the rate of the reaction, the ligation process was designed to be dependent on the presence of a complementary oligonucleotide template.

  7. Endocrine profile of patients with post-tubal-ligation syndrome.

    Science.gov (United States)

    Hargrove, J T; Abraham, G E

    1981-07-01

    The endocrine profile of the midluteal phase was assessed in 29 patients with the post-tubal-ligation syndrome, consisting of pain, bleeding and premenstrual tension. Compared to normal controls, the patients had a high serum estradiol and a low serum progesterone level. This abnormal luteal function may be responsible for the symptoms observed and may also explain the failure to conceive following successful reversal of tubal ligation. It is recommended that patients seeking sterilization reversal be screened for abnormal luteal function preoperatively. Selection of sterilization procedures that minimize alteration in luteal function should be given high priority.

  8. Sequelae of tubal ligation: an analysis of 75 consecutive hysterectomies.

    Science.gov (United States)

    Stock, R J

    1984-10-01

    Seventy-five consecutive patients undergoing hysterectomy subsequent to elective sterilization were studied regarding the occurrence of the post-tubal-ligation syndrome of pelvic pain and/or menorrhagia. Twenty patients were clinically considered to have the syndrome. In none of the patients operated on specifically for menstrual abnormalities could the findings be remotely attributed to the sterilization procedure. Five of the 20 patients had pelvic varicosities and one had pelvic adhesions that may have been a consequence of previous sterilization and conceivably the cause for the pelvic pain for which the patients were undergoing hysterectomy. I question the legitimacy of the post-tubal-ligation syndrome as a reason for hysterectomy.

  9. Alternative Okazaki Fragment Ligation Pathway by DNA Ligase III

    Directory of Open Access Journals (Sweden)

    Hiroshi Arakawa

    2015-06-01

    Full Text Available Higher eukaryotes have three types of DNA ligases: DNA ligase 1 (Lig1, DNA ligase 3 (Lig3 and DNA ligase 4 (Lig4. While Lig1 and Lig4 are present in all eukaryotes from yeast to human, Lig3 appears sporadically in evolution and is uniformly present only in vertebrates. In the classical, textbook view, Lig1 catalyzes Okazaki-fragment ligation at the DNA replication fork and the ligation steps of long-patch base-excision repair (BER, homologous recombination repair (HRR and nucleotide excision repair (NER. Lig4 is responsible for DNA ligation at DNA double strand breaks (DSBs by the classical, DNA-PKcs-dependent pathway of non-homologous end joining (C-NHEJ. Lig3 is implicated in a short-patch base excision repair (BER pathway, in single strand break repair in the nucleus, and in all ligation requirements of the DNA metabolism in mitochondria. In this scenario, Lig1 and Lig4 feature as the major DNA ligases serving the most essential ligation needs of the cell, while Lig3 serves in the cell nucleus only minor repair roles. Notably, recent systematic studies in the chicken B cell line, DT40, involving constitutive and conditional knockouts of all three DNA ligases individually, as well as of combinations thereof, demonstrate that the current view must be revised. Results demonstrate that Lig1 deficient cells proliferate efficiently. Even Lig1/Lig4 double knockout cells show long-term viability and proliferate actively, demonstrating that, at least in DT40, Lig3 can perform all ligation reactions of the cellular DNA metabolism as sole DNA ligase. Indeed, in the absence of Lig1, Lig3 can efficiently support semi-conservative DNA replication via an alternative Okazaki-fragment ligation pathway. In addition, Lig3 can back up NHEJ in the absence of Lig4, and can support NER and HRR in the absence of Lig1. Supporting observations are available in less elaborate genetic models in mouse cells. Collectively, these observations raise Lig3 from a niche

  10. Alternative Okazaki Fragment Ligation Pathway by DNA Ligase III.

    Science.gov (United States)

    Arakawa, Hiroshi; Iliakis, George

    2015-06-23

    Higher eukaryotes have three types of DNA ligases: DNA ligase 1 (Lig1), DNA ligase 3 (Lig3) and DNA ligase 4 (Lig4). While Lig1 and Lig4 are present in all eukaryotes from yeast to human, Lig3 appears sporadically in evolution and is uniformly present only in vertebrates. In the classical, textbook view, Lig1 catalyzes Okazaki-fragment ligation at the DNA replication fork and the ligation steps of long-patch base-excision repair (BER), homologous recombination repair (HRR) and nucleotide excision repair (NER). Lig4 is responsible for DNA ligation at DNA double strand breaks (DSBs) by the classical, DNA-PKcs-dependent pathway of non-homologous end joining (C-NHEJ). Lig3 is implicated in a short-patch base excision repair (BER) pathway, in single strand break repair in the nucleus, and in all ligation requirements of the DNA metabolism in mitochondria. In this scenario, Lig1 and Lig4 feature as the major DNA ligases serving the most essential ligation needs of the cell, while Lig3 serves in the cell nucleus only minor repair roles. Notably, recent systematic studies in the chicken B cell line, DT40, involving constitutive and conditional knockouts of all three DNA ligases individually, as well as of combinations thereof, demonstrate that the current view must be revised. Results demonstrate that Lig1 deficient cells proliferate efficiently. Even Lig1/Lig4 double knockout cells show long-term viability and proliferate actively, demonstrating that, at least in DT40, Lig3 can perform all ligation reactions of the cellular DNA metabolism as sole DNA ligase. Indeed, in the absence of Lig1, Lig3 can efficiently support semi-conservative DNA replication via an alternative Okazaki-fragment ligation pathway. In addition, Lig3 can back up NHEJ in the absence of Lig4, and can support NER and HRR in the absence of Lig1. Supporting observations are available in less elaborate genetic models in mouse cells. Collectively, these observations raise Lig3 from a niche-ligase to a

  11. Characterization of salt tolerance in ectoine-transformed tobacco plants (Nicotiana tabaccum): photosynthesis, osmotic adjustment, and nitrogen partitioning.

    Science.gov (United States)

    Moghaieb, R E A; Tanaka, N; Saneoka, H; Murooka, Y; Ono, H; Morikawa, H; Nakamura, A; Nguyen, N T; Suwa, R; Fujita, K

    2006-02-01

    Ectoine (1,4,5,6-tetrahydro-2-methyl-4-pyrimidinecarboxylic acid) biosynthetic genes (ect. ABC) from Halomonas elongata were introduced to tobacco plants using an Agrobacterium-mediated gene delivery system. The genes for ectoine biosynthesis were integrated in a stable manner into the tobacco genome and the corresponding transcripts were expressed. The concentration of ectoine under salt-stress conditions was higher in the roots than in leaves. A close relationship was found between stomatal conductance and the amount of transported nitrogen, suggesting that water transport through the xylem in the stem and transpiration may be involved in nitrogen transport to leaves. The data indicate that the turgor values of the ectoine transgenic lines increased with increasing salt concentration. The data revealed two ways in which ectoine enhanced salinity tolerance of tobacco plants. First, ectoine improved the maintenance of root function so that water is taken up consistently and supplied to shoots under saline conditions. Second, ectoine enhanced the nitrogen supply to leaves by increasing transpiration and by protecting Rubisco proteins from deleterious effects of salt, thereby improving the rate of photosynthesis.

  12. Pros and cons of patent ductus arteriosus ligation: hemodynamic changes and other morbidities after patent ductus arteriosus ligation.

    Science.gov (United States)

    Noori, Shahab

    2012-04-01

    Although surgical ligation of a persistent patent ductus arteriosus resolves the adverse hemodynamic consequences of the systemic-to-pulmonary shunt and may confer some long-term benefits, it is also associated with both immediate and long-term negative effects. The population that benefits from or is harmed by the procedure is not clearly defined. Although indiscriminate ligation of the patent ductus arteriosus in all patients is not supported by the available information, the recent suggestion declaring the ductus harmless is not supported either. As we await the results of appropriately designed randomized control studies to define the indications for ligation, we must use clinical and echocardiographic indicators of a hemodynamically significant ductus arteriosus and thoughtful assessment of each individual patient to help guide us in addressing this complex problem.

  13. Electron energy-loss spectroscopy characterization and microwave absorption of iron-filled carbon-nitrogen nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Che Renchao [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, PO Box 603, Beijing, 100080 (China); Liang Chongyun [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, PO Box 603, Beijing, 100080 (China); Shi Honglong [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, PO Box 603, Beijing, 100080 (China); Zhou Xingui [Key Lab of New Ceramic Fibers and Composites, School of Aerospace and Materials Engineering, National University of Defense Technology, Changsha 410073 (China); Yang Xinan [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, PO Box 603, Beijing, 100080 (China)

    2007-09-05

    Iron-filled carbon-nitrogen (Fe/CN{sub x}) nanotubes and iron-filled carbon (Fe/C) nanotubes were synthesized at 900 deg. C through a pyrolysis reaction of ferrocene/acetonitrile and ferrocene/xylene, respectively. The differences of structure and composition between the Fe/CN{sub x} nanotubes and Fe/C nanotubes were investigated by transmission electron microscopy and electron energy-loss spectroscopy (EELS). It was found that the morphology of Fe/CN{sub x} nanotubes is more corrugated than that of the Fe/C nanotubes due to the incorporation of nitrogen. By comparing the Fe L{sub 2,3} electron energy-loss spectra of Fe/CN{sub x} nanotubes to those of the Fe/C nanotubes, the electron states at the interface between Fe and the tubular wall of both Fe/CN{sub x} nanotubes and Fe/C nanotubes were investigated. At the boundary between Fe and the wall of a CN{sub x} nanotube, the additional electrons contributed from the doped 'pyridinic-like' nitrogen might transfer to the empty 3d orbital of the encapsulated iron, therefore leading to an intensity suppression of the iron L{sub 2,3} edge and an intensity enhancement of the carbon K edge. However, such an effect could not be found in Fe/C nanotubes. Microwave absorption properties of both Fe/CN{sub x} and Fe/C nanocomposites at 2-18 GHz band were studied.

  14. Sequence fidelity of a template-directed PNA-ligation reaction.

    Science.gov (United States)

    Mattes, A; Seitz, O

    2001-10-21

    The ligation method and an appended duplex-stabilizing dye affect both yield and sequence selectivity of a template-controlled PNA-ligation. The highest selectivity was obtained with a peptide condensation that formed an abasic site.

  15. Characterization of pII Family (GlnK1, GlnK2, GlnB) Protein Uridylylation in Response to Nitrogen Availability for Rhodopseudomonas palustris

    Energy Technology Data Exchange (ETDEWEB)

    Connelly, Heather M [ORNL; Pelletier, Dale A [ORNL; Lu, Tse-Yuan [ORNL; Lankford, Patricia K [ORNL; Hettich, Robert {Bob} L [ORNL

    2006-01-01

    The GlnK and GlnB proteins are members of the pII signal transduction protein family, which is essential in nitrogen regulation due to this protein family's ability to sense internal cellular ammonium levels and control cellular response. The role of GlnK in nitrogen regulation has been studied in a variety of bacteria but previously has been uncharacterized in the purple nonsulfur anoxygenic phototropic bacterium Rhodopseudomonas palustris. R. palustris has tremendous metabolic versatility in its modes of energy generation and carbon metabolism, and it employs a sensitive nitrogen-ammonium regulation system that may vary from that of other commonly studied bacteria. In R. palustris, there are three annotated forms of pII proteins: GlnK1, GlnK2, and GlnB. Here we describe, for the first time, the characterization of GlnK1, GlnK2, and GlnB modifications as a response to nitrogen availability, thereby providing information about how this bacterium regulates the AmtB ammonium transporter and glutamine synthetase, which controls the rate of glutamate to glutamine conversion. Using a strategy of creating C-terminally tagged GlnK and GlnB proteins followed by tandem affinity purification in combination with top-down mass spectrometry, four isoforms of the GlnK2 and GlnB proteins and two isoforms of the GlnK1 protein were characterized at high resolution and mass accuracy. Wild-type or endogenous expression of all three proteins was also examined under normal ammonium conditions and ammonium starvation to ensure that the tagging and affinity purification methods employed did not alter the natural state of the proteins. All three proteins were found to undergo uridylylation under ammonium starvation conditions, presumably to regulate the AmtB ammonium transporter and glutamine synthetase. Under high-ammonium conditions, the GlnK1, GlnK2, and GlnB proteins are unmodified. This experimental protocol involving high-resolution mass spectrometry measurements of intact

  16. Assessment and treatment of post patent ductus arteriosus ligation syndrome.

    LENUS (Irish Health Repository)

    El-Khuffash, Afif F

    2014-07-01

    To compare differences in tissue Doppler imaging, global longitudinal strain (GLS), and cardiac troponin T (cTnT) between infants with low (<200 mL\\/kg\\/min) and high (>200 mL\\/kg\\/min) left ventricular (LV) output 1 hour after duct ligation and assess the impact of milrinone treatment on cardiac output and myocardial performance.

  17. Synthesis of coumarin or ferrocene labeled nucleosides via Staudinger ligation

    Directory of Open Access Journals (Sweden)

    Kois Pavol

    2006-11-01

    Full Text Available Abstract Background Reaction of azides with triaryl phosphines under mild conditions gives iminophosphoranes which can react with almost any kind of electrophilic reagent, e.g. aldehydes/ketones to form imines or esters to form amides. This so-called Staudinger ligation has been employed in a wide range of applications as a general tool for bioconjugation including specific labeling of nucleic acids. Results A new approach for the preparation of labeled nucleosides via intermolecular Staudinger ligation is described. Reaction of azidonucleosides with triphenylphosphine lead to iminophosphorane intermediates, which react subsequently with derivatives of coumarin or ferrocene to form coumarin or ferrocene labeled nucleosides. Fluorescent properties of coumarin labeled nucleosides are determined. Conclusion New coumarin and ferrocene labeled nucleosides were prepared via intermolecular Staudinger ligation. This reaction joins the fluorescent coumarin and biospecific nucleoside to the new molecule with promising fluorescent and electrochemical properties. The isolated yields of products depend on the structure of azidonucleoside and carboxylic acids. A detailed study of the kinetics of the Staudinger ligation with nucleoside substrates is in progress.

  18. Endoscopic banding ligation can effectively resect hyperplastic Polyps of stomach

    Institute of Scientific and Technical Information of China (English)

    Ching-Chu Lo; Wen-Chi Chen; E-Ming Wang; Kwok-Hung Lai; Ping-I Hsu; Gin-Ho Lo; Hui-Hwa Tseng; Hui-Chun Chen; Ping-Ning Hsu; Chiun-Ku Lin; Hoi-Hung Chan; Wei-Lun Tsai

    2003-01-01

    AIM: Bleeding and perforation are the major and serious complications associated with endoscopic polypectomy. To develop a safe and effective method to resect hyperplastic polyps of the stomach, we employed rubber bands to strangulate hyperplastic polyps and to determine the possibility of inducing avascular necrosis in these lesions.METHODS: Forty-seven patients with 72 hyperplastic polyps were treated with endoscopic banding ligation (EBL). On 14 days after endoscopic ligation, follow-up endoscopies were performed to assess the outcomes of the strangulated polyps.RESULTS: After being strangulated by the rubber bands,all of the polyps immediately became congested (100 %),and then developed cyanotic changes (100 %) approximately 4 minutes later. On follow-up endoscopy 2 weeks later, all the polyps except one had dropped off. The only one residual polyp shrank with a rubber band in its base, and it also dropped off spontaneously during subsequent follow-up.No complications occurred during or following the ligation procedures.CONCLUSION: Gastric polyps develop avascular necrosis following ligation by rubber bands. Employing suction equipment, EBL can easily capture sessile polyps. It is an easy, safe and effective method to eradicate hyperplastic polyps of the stomach.

  19. PUNICA GRANATUM ATTENUATES SCIATIC NERVE LIGATION INDUCED-NEUROPATHIC PAIN

    Directory of Open Access Journals (Sweden)

    Ramica Sharma et al.

    2012-02-01

    Full Text Available The study has been designed to investigate the effect of aqueous extract of rind of Punica granatum in sciatic nerve ligation induced-neuropathic pain in rats. Surgical procedure was performed with sciatic nerve ligation to develop neuropathic pain in rats. The development of neuropathic pain was assessed by employing behaviour parameters such as hyperalgesia and allodynia. Further, the functionality of sciatic nerve was assessed using the histopathological study of myelinated and unmyelinated fibers in sciatic nerve. Moreover, the oxidative stress was assessed by estimating serum thiobarbituric acid reactive substances (TBARS, catalase, glutathione and tissue TBARS and Superoxide dismutase (SOD. Rats exposed to sciatic nerve ligation produced marked increase in oxidative stress, which was assessed in terms of TBARS and SOD along with decrease in the level of catalase and glutathione. Moreover, it develops neuropathic pain by impairing the normal functions of myelinated and unmyelinated fibers in sciatic nerve. Treatment with aqueous extract of Punica granatum extract (100mg/kg, p.o markedly prevented sciatic nerve ligation-induced neuropathy and oxidative stress by increasing the pain threshold, by improving the functionality of sciatic nerve, by decreasing serum and tissue TBARS and tissue SOD, by increasing levels of serum glutathione and catalase. It may be concluded that Punica granatum extract reduced the oxidative stress via inhibiting p38MAPK and alleviates neuropathic symptoms and consequently improved the functionality of sciatic nerve and prevents sciatic nerve ligation–induced neuropathic pain.

  20. Adrenal function in preterm infants undergoing patent ductus arteriosus ligation.

    LENUS (Irish Health Repository)

    El-Khuffash, Afif

    2013-01-01

    Targeted milrinone treatment for low left ventricular output (LVO) reduces the incidence of acute cardiorespiratory instability following ligation of patent ductus arteriosus (PDA) in preterm infants. Despite this, some infants continue to experience postoperative deterioration. Adrenal insufficiency related to prematurity has been postulated as a possible mechanism.

  1. Ectopic pregnancy after two times tubal ligation: a case report

    Directory of Open Access Journals (Sweden)

    Farideh Keypour

    2013-06-01

    Full Text Available Background: Tubal sterilization is the permanent and effective contraception method. This can be performed at any time, but at least half are performed in conjunction with cesarean or vaginal delivery and are termed puerperal. The most complication after tubal ligation is ectopic pregnancy. Ectopic pregnancy is the leading cause of maternal death in first trimester.Case presentation: We present a 33 years old woman gravida5, para4, all normal vaginal delivery, presented with complaints of delayed menstrual period, pelvic pain and spotting. She underwent tubal ligation for two times. For the first time she had puerperal Pomeroy tubal sterilization after third child delivery. Intra uterine pregnancy occurred three years later. One day after vaginal delivery of fourth child, she underwent post partum tubal ligation with the Parkland method. Tubal pregnancy occurred nine months later. Physical examination identified acute abdomen. Pelvic ultrasound showed no gestational sac in uterine cavity. The sac with fetal pole was in right adnexa. Beta-HCG was 2840mIU/ml. She underwent laparotomy. Surgical management included salpingectomy with cornual resection in both sides. The surgery identified Ectopic pregnancy.Conclusion: Any symptoms of pregnancy in a woman after tubal ligation must be investigated; an ectopic pregnancy should be excluded. Ectopic pregnancy must be considered, in any woman with lower abdominal pain, missed period and vaginal bleed-ing. Conception after tubal sterilization can be explained by fistula formation and re-canalization of fallopian tube.

  2. Optimization of ligation reaction conditions in gene synthesis.

    Science.gov (United States)

    Theriault, N Y; Carter, J B; Pulaski, S P

    1988-05-01

    Several phosphorylation, annealing and ligation reaction conditions have been investigated for the enzymatic assembly of genes of interest. The use of longer oligodeoxyribonucleotides (40-60 bases long) also improved the enzymatic reaction. Furthermore, the use of longer oligonucleotides and the elimination of long stretches of G's or C's lowered the mutation rate.

  3. Subfascial endoscopic ligation in the treatment of incompetent perforating veins

    NARCIS (Netherlands)

    E.G.J.M. Pierik; C.H. Wittens; H. van Urk (Hero)

    1995-01-01

    textabstractObjectives: To assess the technique of subfascial endoscopic ligation of incompetent perforatory veins by use of a mediastinoscope. Design: Prospective open clinic study. Setting: Two Departments of Surgery. Materials and Methods: Thirty-eight consecutive patients (40 legs) with recu

  4. Enzymatic Ligation of Large Biomolecules to DNA

    DEFF Research Database (Denmark)

    Sørensen, Rasmus Schøler; Okholm, Anders Hauge; Schaffert, David Henning;

    2013-01-01

    The ability to synthesize, characterize, and manipulate DNA forms the foundation of a range of advanced disciplines including genomics, molecular biology, and biomolecular engineering. In particular for the latter field, DNA has proven useful as a structural or functional component in nanoscale s....... As a proof of principle, parallelly labeled oligonucleotides were used to produce nanopatterned DNA origami structures, demonstrating rapid and versatile incorporation of non-DNA components into DNA nanoarchitectures....

  5. Fabrication, characterization and application of nitrogen-containing carbon nanospheres obtained by pyrolysis of lignosulfonate/poly(2-ethylaniline).

    Science.gov (United States)

    He, Zhi-Wei; Lü, Qiu-Feng; Lin, Qilang

    2013-01-01

    Lignosulfonate/poly(2-ethylaniline) (LS-PEA) composite nanospheres were prepared via in situ polymerization of 2-ethylaniline (EA) with lignosulfonate (LS) as a dispersant. LS-PEA nanospheres with an average diameter of 155 nm were obtained at an optimal LS concentration of 20 wt.%. Subsequently, nitrogen-containing carbon nanospheres were fabricated via direct pyrolysis of the LS-PEA composite nanospheres at 600-800 °C. The carbon nanospheres prepared by pyrolysis were used as anodes of lithium-ion batteries. The first charge and discharge capacity of carbon nanospheres prepared at 700 °C at current densities of 60 and 100 mA g(-1) were 980 and 432 mAh g(-1), and 764 and 342 mAh g(-1), respectively. The batteries still owned a high capacity of 353 and 296 mAh g(-1) after 20 cycles. The results indicated that these nitrogen-containing carbon nanospheres could be used as a promising candidate for electrode materials of lithium-ion batteries.

  6. Corrosion behavior of self-ligating and conventional metal brackets

    Directory of Open Access Journals (Sweden)

    Lúcio Henrique Esmeraldo Gurgel Maia

    2014-04-01

    Full Text Available Objective: To test the null hypothesis that the aging process in self-ligating brackets is not higher than in conventional brackets. Methods: Twenty-five conventional (GN-3M/Unitek; GE-GAC; VE-Aditek and 25 self-ligating (SCs-3M/Unitek; INs-GAC; ECs-Aditek metal brackets from three manufacturers (n = 150 were submitted to aging process in 0.9% NaCl solution at a constant temperature of 37 ± 1ºC for 21 days. The content of nickel, chromium and iron ions in the solution collected at intervals of 7, 14 and 21 days was quantified by atomic absorption spectrophotometry. After the aging process, the brackets were analyzed by scanning electron microscopy (SEM under 22X and 1,000X magnifications. Results: Comparison of metal release in self-ligating and conventional brackets from the same manufacturer proved that the SCs group released more nickel (p < 0.05 than the GN group after 7 and 14 days, but less chromium (p < 0.05 after 14 days and less iron (p < 0.05 at the three experimental time intervals. The INs group released less iron (p < 0.05 than the GE group after 7 days and less nickel, chromium and iron (p < 0.05 after 14 and 21 days. The ECs group released more nickel, chromium and iron (p < 0.05 than the VE group after 14 days, but released less nickel and chromium (p < 0.05 after 7 days and less chromium and iron (p < 0.05 after 21 days. The SEM analysis revealed alterations on surface topography of conventional and self-ligating brackets. Conclusions: The aging process in self-ligating brackets was not greater than in conventional brackets from the same manufacturer. The null hypothesis was accepted.

  7. Infrared coagulation versus rubber band ligation in early stage hemorrhoids

    Directory of Open Access Journals (Sweden)

    P.J. Gupta

    2003-10-01

    Full Text Available The ideal therapy for early stages of hemorrhoids is always debated. Some are more effective but are more painful, others are less painful but their efficacy is also lower. Thus, comfort or efficacy is a major concern. In the present randomized study, a comparison is made between infrared coagulation and rubber band ligation in terms of effectiveness and discomfort. One hundred patients with second degree bleeding piles were randomized prospectively to either rubber band ligation (N = 54 or infrared coagulation (N = 46. Parameters measured included postoperative discomfort and pain, time to return to work, relief in incidence of bleeding, and recurrence rate. The mean age was 38 years (range 19-68 years. The mean duration of disease was 17.5 months (range 12 to 34 months. The number of male patients was double that of females. Postoperative pain during the first week was more intense in the band ligation group (2-5 vs 0-3 on a visual analogue scale. Post-defecation pain was more intense with band ligation and so was rectal tenesmus (P = 0.0059. The patients in the infrared coagulation group resumed their duties earlier (2 vs 4 days, P = 0.03, but also had a higher recurrence or failure rate (P = 0.03. Thus, we conclude that band ligation, although more effective in controlling symptoms and obliterating hemorrhoids, is associated with more pain and discomfort to the patient. As infrared coagulation can be conveniently repeated in case of recurrence, it could be considered to be a suitable alternative office procedure for the treatment of early stage hemorrhoids.

  8. Level of arterial ligation in rectal cancer surgery: Low tie preferred over high tie. A review

    NARCIS (Netherlands)

    M.M. Lange (Marilyne); M. Buunen (Mark); C.J.H. van de Velde (Cornelis)

    2008-01-01

    textabstractConsensus does not exist on the level of arterial ligation in rectal cancer surgery. From oncologic considerations, many surgeons apply high tie arterial ligation (level of inferior mesenteric artery). Other strategies include ligation at the level of the superior rectal artery, just cau

  9. Synthesis, Characterization, and Tribological Evaluation of TiO2-Reinforced Boron and Nitrogen co-Doped Reduced Graphene Oxide Based Hybrid Nanomaterials as Efficient Antiwear Lubricant Additives.

    Science.gov (United States)

    Jaiswal, Vinay; Kalyani; Umrao, Sima; Rastogi, Rashmi B; Kumar, Rajesh; Srivastava, Anchal

    2016-05-11

    The microwave-synthesized reduced graphene oxide (MRG), boron-doped reduced graphene oxide (B-MRG), nitrogen-doped reduced graphene oxide (N-MRG), boron-nitrogen-co-doped reduced graphene oxide (B-N-MRG), and TiO2-reinforced B-N-MRG (TiO2-B-N-MRG) nanomaterials have been synthesized and characterized by various state-of-the-art techniques, like Raman spectroscopy, powder X-ray diffraction, scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy, high-resolution transmission electron microscopy, and X-ray photoelectron spectroscopy. Furthermore, the tribological properties of prepared nanomaterials as antiwear additives in neutral paraffin oil have been evaluated using a four-ball machine at an optimized additive concentration (0.15% w/v). The tribological parameters, like mean wear scar diameter, coefficient of friction, and wear rates, revealed that these nanomaterials have potential to be developed as environmentally friendly sulfated-ash-, phosphorus-, and sulfur-free antiwear lubricant additives. The friction- and wear-reducing behavior of MRG increased upon successive doping of nitrogen, boron, and both nitrogen and boron. Among these additives, B-N-co-doped MRG shows superior tribological behavior in paraffin base oil. Besides this, the load-carrying properties of B-N-co-doped MRG have significantly improved after its reinforcement with TiO2 nanoparticles. A comparative study of the surface morphology of a lubricated track in the presence of various additives has been assessed by SEM and contact-mode atomic force microscopy. The X-ray photoelectron spectroscopy studies have proved that the excellent lubrication properties of TiO2-B-N-MRG are due to the in situ formation of a tribofilm composed of boron nitride, adsorbed graphene layers, and tribosintered TiO2 nanoparticles during the tribocontact. Being sulfur-, halogen-, and phosphorus-free, these graphene-based nanomaterials act as green antiwear additives, protecting interacting

  10. Synthesis, characterization and tin/copper-nitrogen substitutional effect on photocatalytic activity of honeycomb ordered P2-Na2Ni2TeO6

    Science.gov (United States)

    Kadari, Ramaswamy; Velchuri, Radha; Sreenu, K.; Ravi, Gundeboina; Munirathnam, Nagegownivari R.; Vithal, Muga

    2016-11-01

    We have successfully prepared visible light active tin/copper-nitrogen co-doped honeycomb ordered P2-Na2Ni2TeO6 photocatalysts by solid state/ion exchange methods. Powder XRD, TG analysis, SEM, surface area, O-N-H analysis, ICP-OES, FT-IR and UV-DRS measurements are employed to characterize all the samples. All the doped compositions adopted hexagonal lattice with space group P63/mcm. The photocatalytic activity of all the samples was studied against the degradation of methyl violet (MV) and methylene blue (MB) under visible light irradiation. The variation of the photocatalytic activity due to the substitution of cation, anion and co-doping in Na2Ni2TeO6 is investigated. Co-doped samples have exhibited higher activity compared to rest of the materials. The role of reactive intermediate species in the photocatalytic degradation of dyes is also studied using appropriate scavengers.

  11. Enzymes involved in DNA ligation and end-healing in the radioresistant bacterium Deinococcus radiodurans

    Directory of Open Access Journals (Sweden)

    Shevelev Igor V

    2007-08-01

    Full Text Available Abstract Background Enzymes involved in DNA metabolic events of the highly radioresistant bacterium Deinococcus radiodurans are currently examined to understand the mechanisms that protect and repair the Deinococcus radiodurans genome after extremely high doses of γ-irradiation. Although several Deinococcus radiodurans DNA repair enzymes have been characterised, no biochemical data is available for DNA ligation and DNA endhealing enzymes of Deinococcus radiodurans so far. DNA ligases are necessary to seal broken DNA backbones during replication, repair and recombination. In addition, ionizing radiation frequently leaves DNA strand-breaks that are not feasible for ligation and thus require end-healing by a 5'-polynucleotide kinase or a 3'-phosphatase. We expect that DNA ligases and end-processing enzymes play an important role in Deinococcus radiodurans DNA strand-break repair. Results In this report, we describe the cloning and expression of a Deinococcus radiodurans DNA ligase in Escherichia coli. This enzyme efficiently catalyses DNA ligation in the presence of Mn(II and NAD+ as cofactors and lysine 128 was found to be essential for its activity. We have also analysed a predicted second DNA ligase from Deinococcus radiodurans that is part of a putative DNA repair operon and shows sequence similarity to known ATP-dependent DNA ligases. We show that this enzyme possesses an adenylyltransferase activity using ATP, but is not functional as a DNA ligase by itself. Furthermore, we identified a 5'-polynucleotide kinase similar to human polynucleotide kinase that probably prepares DNA termini for subsequent ligation. Conclusion Deinococcus radiodurans contains a standard bacterial DNA ligase that uses NAD+ as a cofactor. Its enzymatic properties are similar to E. coli DNA ligase except for its preference for Mn(II as a metal cofactor. The function of a putative second DNA ligase remains unclear, but its adenylyltransferase activity classifies it as a

  12. Ligation-free ribosome profiling of cell type-specific translation in the brain.

    Science.gov (United States)

    Hornstein, Nicholas; Torres, Daniela; Das Sharma, Sohani; Tang, Guomei; Canoll, Peter; Sims, Peter A

    2016-01-01

    Ribosome profiling has emerged as a powerful tool for genome-wide measurements of translation, but library construction requires multiple ligation steps and remains cumbersome relative to more conventional deep-sequencing experiments. We report a new, ligation-free approach to ribosome profiling that does not require ligation. Library construction for ligation-free ribosome profiling can be completed in one day with as little as 1 ng of purified RNA footprints. We apply ligation-free ribosome profiling to mouse brain tissue to identify new patterns of cell type-specific translation and test its ability to identify translational targets of mTOR signaling in the brain.

  13. Addition of HOBt improves the conversion of thioester-Amine chemical ligation.

    Science.gov (United States)

    Todorovski, Toni; Suñol, David; Riera, Antoni; Macias, Maria J

    2015-11-01

    The syntheses of large peptides and of those containing non-natural amino acids can be facilitated by the application of convergent approaches, dissecting the native sequence into segments connected through a ligation reaction. We describe an improvement of the ligation protocol used to prepare peptides and proteins without cysteine residues at the ligation junction. We have found that the addition of HOBt to the ligation, improves the conversion of the ligation reaction without affecting the epimerization rate or chemoselectivity, and it can be efficiently used with peptides containing phosphorylated amino acids.

  14. SCREENING FOR ANTI ULCER ACTIVITY OF CONVOLVULUS PLURICAULIS USING PYLORIC LIGATION METHOD IN WISTER RATS.

    Directory of Open Access Journals (Sweden)

    Sharath S S

    2015-01-01

    Full Text Available Peptic ulcer disease is a chronic problem of the gastrointestinal tract characterized by mucosal damage secondary to pepsin and gastric acid secretion. Herbal medicines are generally used in cases when drugs are to be used for chronic periods. The study was conducted to evaluate antiulcerogenic activity of convolvulus pluricaulis in wistar rats. The antiulcer activity was carried out employing - Pyloric ligation method. The rats were randomly divided into 4 groups of 6 animals each. First group was given 1ml of 0.1% of vehicle (Tween 80; the second group was treated with ranitidine 50 mg/kg in 1 ml Tween 80. The remaining groups receive 200 mg/kg and 400 mg/kg of Convolvulus pluricaulis alcoholic extract (CPAE in 1 ml Tween 80 respectively. All the drugs were administered orally for five days duration daily in two divided doses. Evaluation of antiulcer activity was done by Ulcer score/ulcer index. Volume of gastric juice secreted, gastric free acidity, total acidity, total protein, pepsin mucin and pH were also estimated. CPAE at a dose of 200 mg/kg inhibited ulcer index by 40.87% and at a dose of 400 mg/kg inhibited ulcer index by 26.64 %. Alcoholic extracts of Convolvulus pluricaulis have shown a significant protection against gastric ulcers in pyloric ligation model.

  15. Extended X-ray absorption fine structure studies of Zn/sub 2/Fe/sub 2/ hybrid hemoglobins: absence of heme bond length changes in half-ligated species

    Energy Technology Data Exchange (ETDEWEB)

    Simolo, K.; Korszun, Z.R.; Stucky, G.; Moffat, K.; McLendon, G.

    1986-07-01

    Metal hybrid hemoglobins, in which Zn(II) replaces Fe(II), have been structurally characterized by extended X-ray absorption structure (EAFS) studies. Since Zn and Fe have very different K absorption edge energies, the structures of the ligated (Fe) and unligated (Zn) sites could be examined independently within a single molecule that mimics an intermediate ligation state. The observed EXAFS spectra and associated structural parameters are compared among the ligand free (..cap alpha..Zn)/sub 2/(..beta..Zn)/sub 2/, half-ligated (..cap alpha..FeCO)/sub 2/(..beta..Zn)/sub 2/ and (..cap alpha..Zn)/sub 2/(..beta..FeCO)/sub 2/, and fully ligated (..cap alpha..FeCO)/sub 2/(..beta..FeCO)/sub 2/ systems.

  16. Model-guided ligation strategy for optimal assembly of DNA libraries.

    Science.gov (United States)

    Ng, Daphne T W; Sarkar, Casim A

    2012-10-01

    DNA ligation is essential to many molecular biology manipulations, but this reaction is often carried out by following generic guidelines or by trial and error. Maximizing the desired ligation product is especially important in DNA library construction for directed evolution experiments since library diversity is directly affected by ligation efficiency. Here, we suggest that display vectors that rely on Type IIP restriction sites for cloning should be redesigned to utilize Type IIS restriction sites instead because ligation yield is significantly improved: we observed up to 15- and 2.6-fold increases in desired products for circular and linear ligation reactions, respectively. To guide ligation optimization more rationally, we developed an easily parameterized thermodynamic model that predicts product distributions based on input DNA concentrations and free energies of the ligation events. We applied this model to study ligation reactions using a ribosome display vector redesigned with Type IIS restriction sites (pRDV2). We computationally predicted and experimentally validated the relative abundance of various products in three-piece linear ligations as well as the extent of transformation from vector-insert circular ligations. Based on our results, we provide general insights into ligation and we outline guidelines for optimizing this reaction for both in vivo and in vitro display methodologies.

  17. Critical evaluation and rate constants of chemoselective ligation reactions for stoichiometric conjugations in water.

    Science.gov (United States)

    Saito, Fumito; Noda, Hidetoshi; Bode, Jeffrey W

    2015-04-17

    Chemoselective ligation reactions have contributed immensely to the development of organic synthesis and chemical biology. However, the ligation of stoichiometric amounts of large molecules for applications such as protein-protein conjugates is still challenging. Conjugation reactions need to be fast enough to proceed under dilute conditions and chemoselective in the presence of unprotected functional groups; the starting materials and products must be stable under the reaction conditions. To compare known ligation reactions for their suitability under these conditions, we determined the second-order rate constants of ligation reactions using peptide substrates with unprotected functional groups. The reaction conditions, the chemoselectivity of the reactions, and the stability of the starting materials and products were carefully evaluated. In some cases, the stability could be improved by modifying the substrate structure. These data obtained under the ligation conditions provide a useful guide to choose an appropriate ligation reaction for synthesis of large molecules by covalent ligation reactions of unprotected substrates in water.

  18. Click chemistry for rapid labeling and ligation of RNA.

    Science.gov (United States)

    Paredes, Eduardo; Das, Subha R

    2011-01-03

    The copper(I)-promoted azide-alkyne cycloaddition reaction (click chemistry) is shown to be compatible with RNA (with free 2'-hydroxyl groups) in spite of the intrinsic lability of RNA. RNA degradation is minimized through stabilization of the Cu(I) in aqueous buffer with acetonitrile as cosolvent and no other ligand; this suggests the general possibility of "ligandless" click chemistry. With the viability of click chemistry validated on synthetic RNA bearing "click"-reactive alkynes, the scope of the reaction is extended to in-vitro-transcribed or, indeed, any RNA, as a click-reactive azide is incorporated enzymatically. Once clickable groups are installed on RNA, they can be rapidly click labeled or conjugated together in click ligations, which may be either templated or nontemplated. In click ligations the resultant unnatural triazole-linked RNA backbone is not detrimental to RNA function, thus suggesting a broad applicability of click chemistry in RNA biological studies.

  19. Characterization of nitrogen-fixing moderate halophilic cyanobacteria isolated from saline soils of Songnen Plain in China

    Institute of Scientific and Technical Information of China (English)

    Wei Zhang; Yujie Feng

    2008-01-01

    Twenty out of 200 isolates of cyanobacteria mainly from saline soils of Songnen Plain of China were successfully grown on BG11 N-free medium. The nitrogen-fixing activity was then demonstrated for the 20 isolates in modified BG11 medium using the acetylene reduction assay. All of them possessed appreciable nitrogenase activity (acetylene reduction) under non-saline conditions; however, at 5% NaCl only 60% of the isolates exhibited a high rate of this activity and 25% were completely negative under these conditions. The cyanobacteria isolates grew well in BG11 medium; nevertheless, growth of the majority of isolates was reduced by about 25-85% in the same medium containing 5% NaCl. Cellulolytic activity was detected in 50% of the 20 strains, amylolytic in 45%, and pectinolytic in 10% of the isolates. The cyanobacteria isolates showed also enzymatic activity under saline conditions (6%). The preliminary identification indicated that seven isolates were Nostoc, two were Microcystis, four were Oscillatoria, six were Anabaena, and one isolate was Synechococcus.

  20. Identification and characterization of phenylacetonitrile as a nitrogenous disinfection byproduct derived from chlorination of phenylalanine in drinking water.

    Science.gov (United States)

    Ma, Xiaoyan; Deng, Jing; Feng, Jiao; Shanaiah, Narasimhamurthy; Smiley, Elizabeth; Dietrich, Andrea M

    2016-10-01

    Unregulated disinfection byproducts (DBPs), including nitrogenous disinfection byproducts (N-DBPs), originating from chlorination of the precursor amino acid phenylalanine in aqueous systems, were identified in laboratory reactions and distributed tap. The major N-DBP identified was phenylacetonitrile, and minor DBPs of benzyl chloride, phenylacetaldehyde, 2-chlorobenzyl cyanide, and 2, 6-diphenylpyridine were also formed. Phenylacetonitrile was generated through decarboxylation, dechlorination and/or hydrolysis processes. With an aromatic structure, phenylacetonitrile has an unpleasant odor of various descriptors and an odor threshold concentration of 0.2 ppt-v as measured through gas chromatography-olfactometry. The half-life of phenylacetonitrile in reagent water and chlorinated water at 19 °C were 121 h and 792 h, respectively. The occurrence of phenylacetonitrile as an N-DBP in tap water was investigated for the first time; the results revealed that μg/L concentrations were present in nine different distributed drinking waters in China and the United States. Phenylacetonitrile deteriorates the aesthetic quality of drinking water and may present risk due to its prolonged existence in drinking water, especially in the presence of residual chlorine.

  1. Isolation and characterization of a Sinorhizobium fredii mutant that cannot utilize proline as the sole carbon and nitrogen source

    Institute of Scientific and Technical Information of China (English)

    HUANG Sheng; BAI Xueliang; MA Qingsheng; TANG Xianlai; WU Bo

    2004-01-01

    Sinorhizobium fredii strain HN01 can use proline as the sole carbon and nitrogen source. A mutant strain GXHN100 unable to catabolize proline was screened from 6000 Tn5gusA5 random insertional mutants of S.fredii strain HN01. Sequencing analysis showed that an open reading frame, named pmrA (proline metabolic relative), was inserted by the Tn5gusA5. A positive clone, named pGXHN100 which containing 3.3kb foreign DNA fragment of S.fredii strain HN01, was isolated from a partial gene library of S.fredii HN01 by colony in situ hybridization. Sequence analysis showed that pGXHN100 contained the entire pmrA gene. The 3.3kb DNA fragment of pGXHN100 was cloned into a broad-host-range cosmid vector pLAFR3 to form plasmid pGXHN200 which was subsequently introduced into GXHN100 to form a complemented strain GXHN200. Plant test showed that GXHN100 was effective and no obvious changes in nitrogenase activity comparing with parental strain. But GXHN100 nodulated 2 days later on soybean and its nodulation efficiency and competitiveness were decreased. The complemented strain GXHN200 restored the nodulation efficiency and competitiveness of GXHN100 to the wild type.

  2. Elastic band ligation of hemorrhoids: Flexible gastroscope or rigid proctoscope?

    Institute of Scientific and Technical Information of China (English)

    M Cazemier; RJF Felt-Bersma; MA Cuesta; CJJ Mulder

    2007-01-01

    AIM: To compare rigid proctoscope and flexible endoscope for elastic band ligation of internal hemorrhoids.METHODS: Patients between 18 and 80 years old, with chronic complaints (blood loss, pain, itching or prolapse)of internal hemorrhoids of grade Ⅰ-Ⅲ, were randomized to elastic band ligation by rigid proctoscope or flexible endoscope (preloaded with 7 bands). Patients were retreated every 6 wk until the cessation of complaints.Evaluation by three-dimensional anal endosonography was performed.RESULTS: Forty-one patients were included (median age 52.0, range 27-79 years, 20 men). Nineteen patients were treated with a rigid proctoscope and twenty two with a flexible endoscope. Twenty-nine patients had grade Ⅰ hemorrhoids, 9 patients had grade Ⅱ hemorrhoids and 3 patients had grade Ⅲ hemorrhoids.All patients needed a minimum of 1 treatment and a maximum of 3 treatments. A median of 4.0 bands was used in the rigid proctoscope group and a median of 6.0 bands was used in the flexible endoscope group (P < 0.05). Pain after ligation tended to be more frequent in patients treated with the flexible endoscope (first treatment: 3 vs 10 patients, P < 0.05). Threedimensional endosonography showed no sphincter defects or alterations in submucosal thickness.CONCLUSION: Both techniques are easy to perform,well tolerated and have a good and fast effect. It is easier to perform more ligations with the flexible endoscope. Additional advantages of the flexible scope are the maneuverability and photographic documentation.However, treatment with the flexible endoscope might be more painful and is more expensive.

  3. DNA hybridization and ligation for directed colloidal assembly

    Science.gov (United States)

    Shyr, Margaret

    Colloidal assembly using DNA hybridization has been pursued as a means assemble non-conventional ordered colloidal structures. However, to date it is undetermined whether DNA hybridization can be used to achieve non-FCC colloidal crystals. Using microcontact printing techniques, we have fabricated covalently bound single stranded DNA (ssDNA) two-dimensional arrays on glass surfaces, which were used to direct the assembly of complementary DNA functionalized polystyrene colloids. Two of the hallmarks of DNA hybridization, sequence specificity and thermal reversibility, were demonstrated. Due to the periodicity of these arrays, laser diffraction was used to directly monitor these structures during assembly. To demonstrate the versatility of the 2D colloidal array assembled via DNA hybridization, a catalytic DNA sequence or DNAzyme was incorporated into the colloidal array system. By tethering the enzymatic strand to the patterned glass surface and the substrate strand to polystyrene colloids, we showed that the DNAzyme could prevent the assembly of the arrays when the required Pb2+ cofactor was provided. Attempts to assemble the colloid arrays and disassemble via the Pb2+-DNAzyme induced cleavage were unsuccessful, likely due to the incomplete cleavage of the multitude of hybridized linkages between each colloid and the surface. Since DNA is not only capable of catalyzing reactions, but also capable of being reacted upon by a variety of biological enzymes, we examined the use of DNA ligase as a means to control the assembly of DNA-functionalized colloids. A three-sequence linker system was used for the hybridization mediated assembly of colloids: one sequence was tethered to the surface of the glass slide or colloids, one was tethered to another colloid surface, and the linker sequence hybridizes simultaneously to both tethered sequences. Once hybridized, the two tethered fragments can be ligated using DNA ligase, resulting in a continuous sequence tethered on one end

  4. Preparation, characterization, non-isothermal reaction kinetics, thermodynamic properties, and safety performances of high nitrogen compound: Hydrazine 3-nitro-1,2,4-triazol-5-one complex

    Energy Technology Data Exchange (ETDEWEB)

    Yi Jianhua [Xi' an Modern Chemistry Research Institute, Xi' an 710065 (China); Zhao Fengqi [Xi' an Modern Chemistry Research Institute, Xi' an 710065 (China)], E-mail: yiren@nwu.edu.cn; Gao Hongxu; Xu Siyu; Wang Minchang; Hu Rongzu [Xi' an Modern Chemistry Research Institute, Xi' an 710065 (China)

    2008-05-01

    A new high nitrogen compound hydrazine 3-nitro-1,2,4-triazol-5-one complex (HNTO) was prepared by the reaction of 3-nitro-1,2,4-triazol-5-one with hydrazine hydrate, and its structure was characterized by means of organic elemental analyzer, FT-IR, XRD, {sup 13}C NMR and {sup 15}N NMR. The non-isothermal reaction kinetics of the main exothermic decomposition reaction of HNTO was investigated by means of DSC. The thermodynamic properties of HNTO were calculated. The results showed that the formation of HNTO is achieved by proton transfer of N(4) atom, and it makes a higher nitrogen content and lower acidity. The reaction mechanism of HNTO is classified as nucleation and growth, and the mechanism function is Avramo-Erofeev equation with n = 2/5. The kinetic parameters of the reaction are E{sub a} = 195.29 kJ mol{sup -1}, lg(A (s{sup -1})) = 19.37, respectively. The kinetic equation can be expressed as: (d{alpha})/(dt) =10{sup 18.97}(1-{alpha})[-ln(1-{alpha})]{sup 3/5}e{sup -2.35x10{sup 4}/T} The safety performances of HNTO were carried out. The critical temperature of thermal explosion are 464.26 and 474.37 K, the adiabatic time-to-explosion is 262 s, the impact sensitivity H{sub 50} = 45.7 cm, the friction sensitivity P = 20% and the electrostatic spark sensitivity E{sub 50} > 5.4 J (no ignition). It shows that HNTO has an insensitive nature as RDX and NTO, etc.

  5. Textural characterization of native and n-alky-bonded silica monoliths by mercury intrusion/extrusion, inverse size exclusion chromatography and nitrogen adsorption.

    Science.gov (United States)

    Thommes, M; Skudas, R; Unger, K K; Lubda, D

    2008-05-16

    Native and n-alkyl-bonded (n-octadecyl) monolithic silica rods with mesopores in the range between 10 and 25 nm and macropores in the range between 1.8 and 6.0 microm were examined by mercury intrusion/extrusion, inverse size exclusion chromatography (ISEC) and nitrogen sorption. Our results reveal very good agreement for the mesopore size distribution obtained from nitrogen adsorption (in combination with an advanced NLDFT analysis) and ISEC. Our studies highlight the importance of mercury porosimetry for the assessment of the macropore size distribution and show that mercury porosimetry is the only method which allows obtaining a combined and comprehensive structural characterization of macroporous/mesoporous silica monoliths. Our data clearly confirm that mercury porosimetry hysteresis and entrapment have different origin, and indicate the intrinsic nature of mercury porosimetry hysteresis in these silica monoliths. Within this context some silica monoliths show the remarkable result of no entrapment of mercury after extrusion from the mesopore system (i.e. for the first intrusion/extrusion cycle). The results of a systematic study of the mercury intrusion/extrusion behavior into native silica monoliths and monoliths with bonded n-alkyl groups reveals that the macro (through) pore structure, which controls the mass transfer to and from the mesopores, here mainly controls the entrapment behavior. Our data suggest that mercury intrusion/extrusion porosimetry does not only allow to obtain a comprehensive pore structure analysis, but can also serve as a tool to estimate the mass transport properties of silica monoliths to be employed in liquid-phase separation processes.

  6. The Effect of Nitrogen Surface Ligands on Propane Metathesis: Design and Characterizations of N-modified SBA15-Supported Schrock-type Tungsten Alkylidyne

    KAUST Repository

    Eid, Ahmed A.

    2014-04-01

    Catalysis, which is primarily a molecular phenomenon, is an important field of chemistry because it requires the chemical conversion of molecules into other molecules. It also has an effect on many fields, including, but not limited to, industry, environment and life Science[1]. Surface Organometallic Chemistry is an effective methodology for Catalysis as it imports the concept and mechanism of organometallic chemistry, to surface science and heterogeneous catalysis. So, it bridges the gap between homogenous and heterogeneous catalysis[1]. The aim of the present research work is to study the effect of Nitrogen surface ligands on the activity of Alkane, Propane in particular, metathesis. Our approach is based on the preparation of selectively well-defined group (VI) transition metal complexes supported onto mesoporous materials, SBA15 and bearing amido and/or imido ligands. We choose nitrogen ligands because, according to the literature, they showed in some cases better catalytic properties in homogenous catalysis in comparison with their oxygen counterparts[2]. The first section covers the modification of a highly dehydroxylated SBA15 surface using a controlled ammonia treatment. These will result in the preparation of two kind of Nitrogen surface ligands: -\\tOne with vicinal silylamine/silanol, (≡SiNH2)(≡SiOH), noted [N,O]SBA15 and, -\\tAnother\\tone\\twith\\tvicinal\\tbis-silylamine moieties (≡SiNH2)2, noted [N,N]SBA15[3]. The second section covers the reaction of Schrock type Tungsten Carbyne [W(≡C- tBu)(CH2-tBu)3] with those N-surface ligands and their characterizations by FT-IR, multiple quantum solid state NMR (1H, 13C), elemental analysis and gas phase analysis. The third section covers the generation of the active site, tungsten hydride species. Their performance toward propane metathesis reaction using the dynamic reactor technique PID compared toward previous well-known catalysts supported on silica oxide or mesoporous materials[4]. A fairly good

  7. Regulation of inter- and intramolecular ligation with T4 DNA ligase in the presence of polyethylene glycol.

    OpenAIRE

    Hayashi, K.; NAKAZAWA, M.; Ishizaki, Y; Hiraoka, N.; Obayashi, A

    1986-01-01

    Polyethylene glycol (PEG) stimulates ligation with T4 DNA ligase. In 10% (w/v) PEG 6,000 solutions, only intermolecular ligation is enhanced by monovalent cations, while both inter- and intramolecular ligation occur without their presence. Similar stimulation was also caused by divalent cations or polyamines in the PEG 6,000 solutions. Such properties of the ligase could be applied to control the extent of inter- and intramolecular ligation. Ligation with cations or polyamines in 10% PEG 6,00...

  8. Syntheses and Characterizations of Two New Coordination Polymers Based on Dicarboxylate and Nitrogen-contained Mixed Ligands

    Institute of Scientific and Technical Information of China (English)

    YU Ling-Ling

    2011-01-01

    Two new carboxylate coordination polymers [Ni(2,3'-oba)(bib)]n] and [Mn(2,4'-oba)(bib)0.5]n(2,3'-oba = 2-(3-carboxyphenoxy)benzoic acid,2,4'-oba = 2-(4-carboxyphenoxy) ben-zoic acid and bib = 1,4-bis(2-methyl-imidazol-yl)butane) have been synthesized and characterized by elemental analysis,IR and X-ray single-crystal diffraction studies.Compound 1 crystallizes in monoclinic,space group P21/c,while compound 2 in the triclinic space group P.Compound 1 displays a one-dimensional ladder-like chain.The dinuclear paddle-wheel secondary building units(SBUs) constructed by four 2,4'-oba2-ligands in compound 2 are linked by bib into a 2D(4,4) layer structure.

  9. Inorganic chemistry. Synthesis and characterization of P₂N₃⁻: an aromatic ion composed of phosphorus and nitrogen.

    Science.gov (United States)

    Velian, Alexandra; Cummins, Christopher C

    2015-05-29

    Aromaticity is predominantly associated with carbon-rich compounds but can also occur in all-inorganic ones. We report the synthesis of the diphosphatriazolate anion, a rare example of a planar aromatic inorganic species. Treatment of azide (N3(-)) in tetrahydrofuran solution with P2A2 (A = C14H10), a source of P2, produced P2N3(-), which we isolated as its [Na-kryptofix-221](+) salt in 22% yield and characterized by single-crystal x-ray diffraction. Salts [Na-kryptofix-221] [P2N3] and [Na-kryptofix-221] [P2(15)NN2] were analyzed by infrared and Raman spectroscopy, (15)N and (31)P nuclear magnetic resonance spectroscopy, and mass spectrometry. The formation of the P2N3(-) anion was investigated using density functional theory, and its aromatic character was confirmed by NICS (nucleus-independent chemical shift) and QTAIM (quantum theory of atoms in molecules) methods.

  10. In Vitro Selection of Optimal DNA Substrates for Ligation by a Water-Soluble Carbodiimide

    Science.gov (United States)

    Harada, Kazuo; Orgel, Leslie E.

    1994-01-01

    We have used in vitro selection to investigate the sequence requirements for efficient template-directed ligation of oligonucleotides at 0 deg C using a water-soluble carbodiimide as condensing agent. We find that only 2 bp at each side of the ligation junction are needed. We also studied chemical ligation of substrate ensembles that we have previously selected as optimal by RNA ligase or by DNA ligase. As anticipated, we find that substrates selected with DNA ligase ligate efficiently with a chemical ligating agent, and vice versa. Substrates selected using RNA ligase are not ligated by the chemical condensing agent and vice versa. The implications of these results for prebiotic chemistry are discussed.

  11. Telmisartan attenuates hepatic fibrosis in bile duct-ligated rats

    Institute of Scientific and Technical Information of China (English)

    En-tong YI; Rui-xia LIU; Yan WEN; Cheng-hong YIN

    2012-01-01

    Aim: To evaluate the antifibrotic effect of telmisartan,an angiotensin Ⅱ receptor blocker,in bile duct-ligated rats.Methods: Adult Sprague-Dawley rats were allocated to 3 groups: sham-operated rats,model rats underwent common bile duct ligation (BDL),and BDL rats treated with telmisartan (8 mg/kg,po,for 4 weeks).The animals were sacrificed on d 29,and liver histology was examined,the Knodell and Ishak scores were assigned,and the expression of angiotensin-converting enzyme (ACE) and ACE2 was evaluated with immunohistochemical staining.The mRNAs and proteins associated with liver fibrosis were evaluated using RTQ-PCR and Western blot,respectively.Results: The mean fibrosis score of BDL rats treated with telmisartan was significantly lower than that of the model rats (1.66±0.87 vs 2.13±0.35,P=0.015).However,there was no significant difference in inflammation between the two groups,both of which showed moderate inflammation.Histologically,treatment with telmisartan significantly ameliorated BDL-caused the hepatic fibrosis.Treatment with telmisartan significantly upregulated the mRNA levels of ACE2 and MAS,and decreased the mRNA levels of ACE,angiotensin Ⅱ type 1 receptor (AT1-R),collagen type Ⅲ,and transforming growth factor β1 (TGF-β1).Moreover,treatment with telmisartan significantly increased the expression levels of ACE2 and MAS proteins,and inhibited the expression levels of ACE and AT1-R protein.Conclusion: Telmisartan attenuates liver fibrosis in bile duct-ligated rats via increasing ACE2 expression level.

  12. Synthesis of heteroglycoclusters by using orthogonal chemoselective ligations

    Directory of Open Access Journals (Sweden)

    Baptiste Thomas

    2012-03-01

    Full Text Available Synthetic heteroglycoclusters are being subjected to increasing interest due to their potential to serve as selective ligands for carbohydrate-binding proteins. In this paper, we describe an expedient strategy to prepare cyclopeptides displaying well-defined distributions and combinations of carbohydrates. By using both oxime ligation and copper(I-catalyzed alkyne–azide cycloaddition, two series of compounds bearing binary combinations of αMan, αFuc or βLac in an overall tetravalent presentation, and either 2:2 or 3:1 relative proportions, have been prepared.

  13. Expressed protein ligation for metalloprotein design and engineering.

    Science.gov (United States)

    Clark, Kevin M; van der Donk, Wilfred A; Lu, Yi

    2009-01-01

    Metalloproteins contain highly specialized metal-binding sites that are designed to accept specific metal ions to maintain correct function. Although many of the sites have been modified with success, the relative paucity of functional group availability within proteinogenic amino acids can sometimes leave open questions about specific functions of the metal binding ligands. Attaining a more thorough analysis of individual amino acid function within metalloproteins has been realized using expressed protein ligation (EPL). Here we describe our recent efforts using EPL to incorporate nonproteinogenic cysteine and methionine analogues into the type 1 copper site found in Pseudomonas aeruginosa azurin.

  14. Synthesis and characterization of nitrogen-rich macrocyclic ligands and an investigation of their coordination chemistry with lanthanum(III).

    Science.gov (United States)

    Wilson, Justin J; Birnbaum, Eva R; Batista, Enrique R; Martin, Richard L; John, Kevin D

    2015-01-01

    Derivatives of the ligand 1,4,7,10-tetraazacyclododecane (cyclen) containing pendant N-heterocyclic donors were prepared. The heterocycles pyridine, pyridazine, pyrimidine, and pyrazine were conjugated to cyclen to give 1,4,7,10-tetrakis(pyridin-2-ylmethyl)-1,4,7,10-tetraazacyclododecane (L(py)), 1,4,7,10-tetrakis(3-pyridazylmethyl)-1,4,7,10-tetraazacyclododecane (L(pyd)), 1,4,7,10-tetrakis(4-pyrimidylmethyl)-1,4,7,10-tetraazacyclododecane (L(pyr)), and 1,4,7,10-tetrakis(2-pyrazinylmethyl)-1,4,7,10-tetraazacyclododecane (L(pz)), respectively. The coordination chemistry of these ligands was explored using the La(3+) ion. Accordingly, complexes of the general formula [La(L)(OTf)](OTf)2, where OTf = trifluoromethanesulfonate and L = L(py) (1), L(pyd) (2), L(pyr) (3), and L(pz) (4), were synthesized and characterized by NMR spectroscopy. Crystal structures of 1 and 2 were also determined by X-ray diffraction studies, which revealed 9-coordinate capped, twisted square-antiprismatic coordination geometries for the central La(3+) ion. The conformational dynamics of 1-4 in solution were investigated by variable-temperature NMR spectroscopy. Dynamic line-shape and Eyring analyses enabled the determination of the activation parameters for the interconversion of enantiomeric forms of the complexes. Unexpectedly, the different pendant N-heterocycles of 1-4 give rise to varying values for the enthalpies and entropies of activation for this process. Density functional theory calculations were carried out to investigate the mechanism of this enantiomeric interconversion. Computed activation parameters were consistent with those experimentally determined for 1 but differed somewhat from those of 2-4.

  15. Successful treatment of plastic bronchitis with low fat diet and subsequent thoracic duct ligation in child with fontan physiology.

    Science.gov (United States)

    Parikh, K; Witte, M H; Samson, R; Teodori, M; Carpenter, J B; Lowe, M C; Morgan, W; Hardin, C; Brown, M; Naughton, Y; Sinha, S; Barber, B J

    2012-06-01

    Plastic bronchitis is a rare condition characterized by the formation and expectoration of long, branching bronchial casts that develop in the tracheobronchial tree and cause airway obstruction. Plastic bronchitis has become increasingly recognized as a feared complication of the Fontan operation with a mortality of up to 50%. We report an 11 year old boy who developed severe plastic bronchitis following Fontan repair and the successful long-term control of cast formation utilizing a low-fat diet and subsequent thoracic duct ligation.

  16. Cationic Gold Clusters Ligated with Differently Substituted Phosphines: Effect of Substitution on Ligand Reactivity and Binding

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Grant E.; Olivares, Astrid M.; Hill, David E.; Laskin, Julia

    2015-01-01

    We present a systematic study of the effect of the number of methyl (Me) and cyclohexyl (Cy) functional groups in monodentate phosphine ligands on the solution-phase synthesis of ligated sub-nanometer gold clusters and their gas-phase fragmentation pathways. Small mixed ligand cationic gold clusters were synthesized using ligand exchange reactions between pre-formed triphenylphosphine ligated (PPh3) gold clusters and monodentate Me- and Cy-substituted ligands in solution and characterized using electrospray ionization mass spectrometry (ESI-MS) and collision-induced dissociation (CID) experiments. Under the same experimental conditions, larger gold-PPh3 clusters undergo efficient exchange of unsubstituted PPh3 ligands for singly Me- and Cy-substituted PPh2Me and PPh2Cy ligands. The efficiency of ligand exchange decreases with an increasing number of Me or Cy groups in the substituted phosphine ligands. CID experiments performed for a series of ligand-exchanged gold clusters indicate that loss of a neutral Me-substituted ligand is preferred over loss of a neutral PPh¬3 ligand while the opposite trend is observed for Cy-substituted ligands. The branching ratio of the competing ligand loss channels is strongly correlated with the electron donating ability of the phosphorous lone pair as determined by the relative proton affinity of the ligand. The results indicate that the relative ligand binding energies increase in the order PMe3 < PPhMe2 < PPh2Me < PPh3< PPh2Cy < PPhCy2< PCy3. Furthermore, the difference in relative ligand binding energies increases with the number of substituted PPh3-mMem or PPh3-mCym ligands (L) exchanged onto each cluster. This study provides the first experimental determination of the relative binding energies of ligated gold clusters containing differently substituted monophosphine ligands, which are important to controlling their synthesis and reactivity in solution. The results also indicate that ligand substitution is an important

  17. Vascular Z-shaped ligation technique in surgical treatmentof haemorrhoid

    Institute of Scientific and Technical Information of China (English)

    KazIm Gemici; Ahmet Okus; Serden Ay

    2015-01-01

    AIM To present the effectiveness of minimal invasivevascular zet ligation in the surgical treatment ofhaemorrhoidal disease (HD).METHODS: Among 138 patients with 2nd-4th gradeinternal HD having several complaints and operatedat our hospital between 2003-2013; 116 patients whoregularly attended 1-year control were included in thestudy. Operation times, postoperative early period pain,satisfaction score, complications and relapse detailswere obtained from computer records retrospectively.Visual Analogous Scale (VAS) scores were used forpatient satisfaction on the 3rd, 7th and 21st days.Technique; fixed suture which is constituted by thefirst leg of the Z-shaped suture (to pass by the mucosaand muscular layer) was put in the pile root in order toensure vascular ligation and fixation. The second legof the Z-shaped suture is constituted by mobile sutureand it passes by the pile mucosa and submucosa whichprolapses 5-10 mm below the first suture.RESULTS: Seventy-five of the patients (65%) weremale, 41 of them (35%) were female and their ageaverage was 41. The mean operation time was 12 ±4.8 min. VAS/satisfaction score was found as 2.2/4.3,1.8/4.0, 1.2/4.4 respectively on the 3rd, 7th, and 21stdays. Four of the patient (3.5%) had relapse.CONCLUSION: This technique is an easily applicable,cost efficient way of operation which increases patientsatisfaction.

  18. TLR9 ligation in pancreatic stellate cells promotes tumorigenesis.

    Science.gov (United States)

    Zambirinis, Constantinos P; Levie, Elliot; Nguy, Susanna; Avanzi, Antonina; Barilla, Rocky; Xu, Yijie; Seifert, Lena; Daley, Donnele; Greco, Stephanie H; Deutsch, Michael; Jonnadula, Saikiran; Torres-Hernandez, Alejandro; Tippens, Daniel; Pushalkar, Smruti; Eisenthal, Andrew; Saxena, Deepak; Ahn, Jiyoung; Hajdu, Cristina; Engle, Dannielle D; Tuveson, David; Miller, George

    2015-11-16

    Modulation of Toll-like receptor (TLR) signaling can have protective or protumorigenic effects on oncogenesis depending on the cancer subtype and on specific inflammatory elements within the tumor milieu. We found that TLR9 is widely expressed early during the course of pancreatic transformation and that TLR9 ligands are ubiquitous within the tumor microenvironment. TLR9 ligation markedly accelerates oncogenesis, whereas TLR9 deletion is protective. We show that TLR9 activation has distinct effects on the epithelial, inflammatory, and fibrogenic cellular subsets in pancreatic carcinoma and plays a central role in cross talk between these compartments. Specifically, TLR9 activation can induce proinflammatory signaling in transformed epithelial cells, but does not elicit oncogene expression or cancer cell proliferation. Conversely, TLR9 ligation induces pancreatic stellate cells (PSCs) to become fibrogenic and secrete chemokines that promote epithelial cell proliferation. TLR9-activated PSCs mediate their protumorigenic effects on the epithelial compartment via CCL11. Additionally, TLR9 has immune-suppressive effects in the tumor microenvironment (TME) via induction of regulatory T cell recruitment and myeloid-derived suppressor cell proliferation. Collectively, our work shows that TLR9 has protumorigenic effects in pancreatic carcinoma which are distinct from its influence in extrapancreatic malignancies and from the mechanistic effects of other TLRs on pancreatic oncogenesis.

  19. Binding-regulated click ligation for selective detection of proteins.

    Science.gov (United States)

    Cao, Ya; Han, Peng; Wang, Zhuxin; Chen, Weiwei; Shu, Yongqian; Xiang, Yang

    2016-04-15

    Herein, a binding-regulated click ligation (BRCL) strategy for endowing selective detection of proteins is developed with the incorporation of small-molecule ligand and clickable DNA probes. The fundamental principle underlying the strategy is the regulating capability of specific protein-ligand binding against the ligation between clickable DNA probes, which could efficiently combine the detection of particular protein with enormous DNA-based sensing technologies. In this work, the feasibly of the BRCL strategy is first verified through agarose gel electrophoresis and electrochemical impedance spectroscopy measurements, and then confirmed by transferring it to a nanomaterial-assisted fluorescence assay. Significantly, the BRCL strategy-based assay is able to respond to target protein with desirable selectivity, attributing to the specific recognition between small-molecule ligand and its target. Further experiments validate the general applicability of the sensing method by tailoring the ligand toward different proteins (i.e., avidin and folate receptor), and demonstrate its usability in complex biological samples. To our knowledge, this work pioneers the practice of click chemistry in probing specific small-molecule ligand-protein binding, and therefore may pave a new way for selective detection of proteins.

  20. Semisynthesis of Ribonuclease A using Intein-Mediated Protein Ligation

    Directory of Open Access Journals (Sweden)

    Ulrich Arnold

    2002-01-01

    Full Text Available The introduction of non-natural amino acid residues or modules into proteins provides a new means to explore the basis for conformational stability, folding/unfolding behavior, or biological function. We exploited intein-mediated protein ligation to produce a semisynthetic ribonuclease A. Of the 124 residues of RNase A, residues 1–94 were linked to an intein. After expression of the fusion protein and thiol-induced cleavage, the RNase A(1–94 fragment possessed a C-terminal thioester. A peptide identical to the C-terminal residues 95–124 of RNase A (with residue 95 being cysteine was successfully ligated to that thioester thereby reconstituting full-length wild-type RNase A. In mass spectrometry, this semisynthetic RNase A proved to be undistinguishable from the control protein, namely recombinant wild-type RNase A. Recombinant wild-type RNase A was obtained by expression of RNase A(1–124–intein fusion protein followed by thiol-induced cleavage and hydrolysis of the thioester. Both proteins showed thermal stabilities (Tm and catalytic activities comparable to the wild-type enzyme, indicating that both proteins folded properly. These results might serve as basis for the semisynthesis of RNase A variants containing non-natural modules in the aforementioned peptide.

  1. Nitrogen and sulfur co-doped TiO2 nanosheets with exposed {001} facets: synthesis, characterization and visible-light photocatalytic activity.

    Science.gov (United States)

    Xiang, Quanjun; Yu, Jiaguo; Jaroniec, Mietek

    2011-03-21

    Nitrogen and sulfur co-doped TiO(2) nanosheets with exposed {001} facets (N-S-TiO(2)) were prepared by a simple mixing-calcination method using the hydrothermally prepared TiO(2) nanosheets powder as a precursor and thiourea as a dopant. The resulting samples were characterized by transmission electron microscope, X-ray diffraction, N(2) adsorption-desorption isotherms, X-ray photoelectron spectroscopy, and UV-Vis absorption spectroscopy. The electronic properties of N,S co-doped TiO(2) were studied using the first-principle density functional theory (DFT). The photocatalytic activity of N-S-TiO(2) was evaluated by degradation of 4-chlorophenol (4-CP) aqueous solution under visible light irradiation. The production of hydroxyl radicals (˙OH) on the surface of visible-light-irradiated samples was detected by photoluminescence technique using terephthalic acid as a probe molecule. The results show that nitrogen and sulfur atoms were successfully incorporated into the lattice of TiO(2), which resulted in N-S-TiO(2) samples exhibiting stronger absorption in the UV-visible range with a red shift in the band gap transition. The first-principle DFT calculations further confirm that N and S co-dopants can induce the formation of new energy levels in the band gap, which is associated with the response of N-S-TiO(2) nanosheets to visible light irradiation. Surprisingly, pure TiO(2) nanosheets show the visible-light photocatalytic activity for the degradation of 4-CP mainly due to the substrate-surface complexation of TiO(2) and 4-CP, which results in extending absorption of titania to visible light region through ligand-to-titanium charge transfer. The N-S-TiO(2) samples studied exhibited an enhanced visible-light photocatalytic activity than pure TiO(2). Especially, the doped TiO(2) sample at the nominal weight ratio of thiourea to TiO(2) powder of 2 showed the highest photocatalytic activity, which was about twice greater than that of Degussa P25. The enhanced activity of

  2. TG-FTIR characterization of coal and biomass single fuels and blends under slow heating rate conditions: Partitioning of the fuel-bound nitrogen

    Energy Technology Data Exchange (ETDEWEB)

    Di Nola, G.; de Jong, W.; Spliethoff, H. [Energy Technology Section, Process and Energy Department, Faculty 3me, Delft University of Technology, Leeghwaterstraat 44, 2628 CA Delft (Netherlands)

    2010-01-15

    The devolatilization behavior of a bituminous coal and different biomass fuels currently applied in the Dutch power sector for co-firing was experimentally investigated. The volatile composition during single fuel pyrolysis as well as during co-pyrolysis was studied using TG-FTIR characterization with the focus on the release patterns and quantitative analysis of the gaseous bound nitrogen species. It was shown that all investigated biomass fuels present more or less similar pyrolysis behavior, with a maximum weight loss between 300 and 380 C. Woody and agricultural biomass materials show higher devolatilization rates than animal waste. When comparing different fuels, the percentage of fuel-bound nitrogen converted to volatile bound-N species (NH{sub 3}, HCN, HNCO) does not correlate with the initial fuel-N content. Biomass pyrolysis resulted in higher volatile-N yields than coal, which potentially indicates that NO{sub x} control during co-firing might be favored. No significant interactions occurred during the pyrolysis of coal/biomass blends at conditions typical of TG analysis (slow heating rate). Evolved gas analysis of volatile species confirmed the absence of mutual interactions during woody biomass co-pyrolysis. However, non-additive behavior of selected gas species was found during slaughter and poultry litter co-pyrolysis. Higher CH{sub 4} yields between 450 and 750 C and higher ammonia and CO yields between 550 and 900 C were measured. Such a result is likely to be attributed to catalytic effects of alkali and alkaline earth metals present in high quantity in animal waste ash. The fact that the co-pyrolysis of woody and agricultural biomass is well modeled by simple addition of the individual behavior of its components permits to predict the mixture's behavior based on experimental data available for single fuels. On the other hand, animal waste co-pyrolysis presented in some cases synergistic effects in gas products although additive behavior

  3. Characterization of nitrogen mustard formamidopyrimidine adduct formation of bis(2-chloroethyl)ethylamine with calf thymus DNA and a human mammary cancer cell line.

    Science.gov (United States)

    Gruppi, Francesca; Hejazi, Leila; Christov, Plamen P; Krishnamachari, Sesha; Turesky, Robert J; Rizzo, Carmelo J

    2015-09-21

    A robust, quantitative ultraperformance liquid chromatography ion trap multistage scanning mass spectrometric (UPLC/MS(3)) method was established to characterize and measure five guanine adducts formed by reaction of the chemotherapeutic nitrogen mustard (NM) bis(2-chloroethyl)ethylamine with calf thymus (CT) DNA. In addition to the known N7-guanine (NM-G) adduct and its cross-link (G-NM-G), the ring-opened formamidopyrimidine (FapyG) monoadduct (NM-FapyG) and cross-links in which one (FapyG-NM-G) or both (FapyG-NM-FapyG) guanines underwent ring-opening to FapyG units were identified. Authentic standards of all adducts were synthesized and characterized by NMR and mass spectrometry. These adducts were quantified in CT DNA treated with NM (1 μM) as their deglycosylated bases. A two-stage neutral thermal hydrolysis was developed to mitigate the artifactual formation of ring-opened FapyG adducts involving hydrolysis of the cationic adduct at 37 °C, followed by hydrolysis of the FapyG adducts at 95 °C. The limit of quantification values ranged between 0.3 and 1.6 adducts per 10(7) DNA bases when the equivalent of 5 μg of DNA hydrolysate was assayed on column. The principal adduct formed was the G-NM-G cross-link, followed by the NM-G monoadduct; the FapyG-NM-G cross-link adduct; and the FapyG-NM-FapyG was below the limit of detection. The NM-FapyG adducts were formed in CT DNA at a level ∼20% that of the NM-G adduct. NM-FapyG has not been previously quanitified, and the FapyG-NM-G and FapyG-NM-FapyG adducts have not been previously characterized. Our validated analytical method was then applied to measure DNA adduct formation in the MDA-MB-231 mammary tumor cell line exposed to NM (100 μM) for 24 h. The major adduct formed was NM-G (970 adducts per 10(7) bases), followed by G-NM-G (240 adducts per 10(7) bases), NM-FapyG (180 adducts per 10(7) bases), and, last, the FapyG-NM-G cross-link adduct (6.0 adducts per 10(7) bases). These lesions are expected to

  4. Level of arterial ligation in total mesorectal excision (TME): An anatomical study

    NARCIS (Netherlands)

    M. Buunen (Mark); M.M. Lange (Marilyne); M. Ditzel (Max); G.J. Kleinrensink (Gert Jan); C.J.H. van de Velde (Cornelis)

    2009-01-01

    textabstractIntroduction: High-tie ligation is a common practice in rectal cancer surgery. However, it compromises perfusion of the proximal limb of the anastomosis. This anatomical study was designed to assess the value of low-tie ligation in order to obtain a tension-free anastomosis. Materials an

  5. A facile avenue to conductive polymer brushes via cyclopentadiene-maleimide Diels-Alder ligation.

    Science.gov (United States)

    Yameen, Basit; Rodriguez-Emmenegger, Cesar; Preuss, Corinna M; Pop-Georgievski, Ognen; Verveniotis, Elisseos; Trouillet, Vanessa; Rezek, Bohuslav; Barner-Kowollik, Christopher

    2013-10-07

    Cyclopentadienyl end-capped poly(3-hexylthiophene) was employed to fabricate conductive surface tethered polymer brushes via a facile route based on cyclopentadiene-maleimide Diels-Alder ligation. The efficient nature of the Diels-Alder ligation was further combined with a biomimetic polydopamine-assisted functionalization of surfaces, making it an access route of choice for P3HT surface immobilization.

  6. Banding ligation versus beta-blockers as primary prophylaxis in esophageal varices

    DEFF Research Database (Denmark)

    Gluud, Lise L; Klingenberg, Sarah; Nikolova, Dimitrinka

    2007-01-01

    To compare banding ligation versus beta-blockers as primary prophylaxis in patients with esophageal varices and no previous bleeding.......To compare banding ligation versus beta-blockers as primary prophylaxis in patients with esophageal varices and no previous bleeding....

  7. One-pot native chemical ligation by combination of two orthogonal thioester precursors.

    Science.gov (United States)

    Asahina, Yuya; Kawakami, Toru; Hojo, Hironobu

    2017-02-09

    We developed a one-pot peptide ligation method using two orthogonal thioester precursors and a protecting group for the ligation reaction between Asp and Cys. Combination of the two precursors facilitated the one-pot operation and yielded the entire polypeptide. The usefulness of this method was successfully demonstrated by the total synthesis of histone H4.

  8. Synthesis, characterization and biological relevance of some metal (II) complexes with oxygen, nitrogen and oxygen (ONO) donor Schiff base ligand derived from thiazole and 2-hydroxy-1-naphthaldehyde

    Science.gov (United States)

    Nagesh, G. Y.; Mruthyunjayaswamy, B. H. M.

    2015-04-01

    The novel Schiff base ligand 2-((2-hydroxynaphthalen-1-yl)methylene)-N-(4-phenylthiazol-2-yl)hydrazinecarboxamide (L) obtained by the condensation of N-(4-phenylthiazol-2-yl)hydrazinecarboxamide with 2-hydroxy-1-naphthaldehyde and its newly synthesized Cu(II), Co(II), Ni(II), Zn(II) and Cd(II) complexes have been characterized by microanalysis, molar conductance, IR, 1H NMR, ESI-mass, UV-Visible, TGA/DTA, ESR and powder X-ray diffraction data to explicate their structures. The IR results confirmed the tridentate binding of the ligand involving oxygen atom of amide carbonyl, azomethine nitrogen and naphthol oxygen. 1H NMR spectral data of the ligand (L) and its Zn(II) complex agreed well with the proposed structures. Thermogravimetric studies for Cu(II) and Ni(II) complexes indicated the presence of coordinated water molecules and the final product is the metal oxide. In order to appraise the effect of antimicrobial activity of metal ions upon chelation, the newly synthesized ligand and its metal complexes were screened for their antimicrobial activity by minimum inhibitory concentration (MIC) method. The DNA cleavage activities were studied using plasmid DNA pBR322 (Bangal re Genei, Bengaluru, Cat. No 105850) as a target molecule by agarose gel electrophoresis method. The brine shrimp bioassay was also carried out to study the in vitro cytotoxicity properties against Artemia salina. Furthermore, the antioxidant activity were determined in vitro by reduction of 1,1-diphenyl-2-picryl hydrazyl (DPPH). The ligand exhibited better in vitro-antioxidant activity than its metal complexes.

  9. Mono- and bis-phosphine-ligated H93G myoglobin: spectral models for ferrous-phosphine and ferrous-CO cytochrome P450.

    Science.gov (United States)

    Sun, Shengfang; Sono, Masanori; Dawson, John H

    2013-10-01

    To further investigate the properties of phosphines as structural and functional probes of heme proteins, mono- and bis-phosphine [tris(hydroxymethyl)phosphine, THMP] adducts of H93G myoglobin (Mb) have been prepared by stepwise THMP titrations of exogenous ligand-free ferric and ferrous H93G Mb, respectively. Bubbling with CO or stepwise titration with imidazole (Im) of the bis-THMP-ligated ferrous protein generated a mixed ligand (THMP/CO or THMP/Im, respectively) ferrous complexes. Stable oxyferrous H93G(THMP) Mb was formed at -40°C by bubbling the mono-THMP-Fe(II) protein with O2. A THMP-ligated ferryl H93G Mb moiety has been partially formed upon addition of H2O2 to the ferric mono-THMP adduct. All the species prepared above have been characterized with UV-visible (UV-vis) absorption and magnetic circular dichroism (MCD) spectroscopy in this study. The six-coordinate ferrous bis-phosphine and mono-phosphine/CO complexes of H93G Mb exhibit characteristic spectral features (red-shifted Soret/unique-shaped MCD visible bands and hyperporphyrin spectra, respectively) that only have been seen for the analogous phosphine or CO-complexes of thiolate-ligated heme proteins such as cytochrome P450 (P450) and Caldariomyces fumago chloroperoxidase (CPO). However, such resemblance is not seen in phosphine-ligated ferric H93G Mb even though phosphine-bound ferric P450 and CPO display hyperporphyrin spectra. In fact, bis-THMP-bound ferric H93G Mb exhibits MCD and UV-vis absorption spectra that are similar to those of bis-amine- and bis-thioether-ligated H93G Mb complexes. This study also further demonstrates the utility of the H93G cavity mutant for preparing novel heme iron coordination structures.

  10. Serotonin-induced blood flow changes in the rat hindlegs after unilateral ligation of the femoral artery. Inhibition by the S2 receptor antagonist ketanserin.

    Science.gov (United States)

    Verheyen, A; Vlaminckx, E; Lauwers, F; Van Den Broeck, C; Wouters, L

    1984-08-01

    Collateral arteries can clearly be visualized in corrosion cast material after ligation of the femoral artery in rats. To characterize the influence of serotonin on the blood circulation under the experimental condition of unilateral ligation, we performed intermuscular thermoflow measurements. The data showed that intraperitoneal serotonin (8.7 and 20 mg.kg-1) injection markedly reduced the muscle temperature in both hindlegs. However, the effect was significantly more pronounced on the ligated side, where the blood was supplied through a collateral circulation, than on the non-ligated side with its normal arterial vasculature. Almost identical changes were obtained in rats with an early as well as in animals with a more advanced stage of collateral development (challenge with 8.7 mg.kg-1 serotonin). Evans blue dye experiments and angiographic data further revealed that, after challenge with 20 mg.kg-1 serotonin, the severe temperature decrease at the ligated side probably reflected a nearly complete blockage of blood supply. Pretreatment with the S2 receptor antagonist ketanserin (2.5 mg.kg-1) resulted in a significant reduction in the extent and duration of the serotonin-induced temperature decrease as revealed by the temperature measurements; such a treatment inhibited also the blockage in blood flow as seen with the other techniques. This study shows that serotonin, through its vasoconstrictive properties, can restrict the blood flow to the lower extremities of the rat, particularly when the blood is supplied through collateral circulation. This probably results in moderate to severe skeletal muscle ischaemia. It also suggests that the vasoconstriction is not only important in the inhibition of collateral blood flow in recently established collaterals but also in collateral vessels in a more advanced stage of development. The in vivo vasoconstriction and subsequent reduction of the blood supply caused by serotonin can be effectively counteracted by

  11. [Is a hysterectomy justifiable to prevent post-tubal ligation syndrome?].

    Science.gov (United States)

    Maheux, R; Fugère, P

    1980-12-01

    Among 2057 tubal ligations performed between 1971-75 in "Hopital Saint-Luc" in Montreal, 78 patients had to be readmitted for hysterectomy. The main indication for hysterectomy among these patients was for menstrual disorders (65%). These menstrual disorders were present at the moment of the tubal ligation in about half of the patients. Among the patients who had to be reoperated for hysterectomy for menstrual disorders and who were asymptomatic at the momemt of their tubal ligation, 88% were using oral contraceptives for a mean period of 5.8 years. The low incidence of hysterectomy post-tubal ligation (3.8%) does not seem to justify a total hysterectomy to prevent what has been described as the "post tubal ligation syndrome" in the patients who are asymptomatic and desire a permanent sterilization. (Author's modified)

  12. In vivo multiphoton imaging of bile duct ligation

    Science.gov (United States)

    Liu, Yuan; Li, Feng-Chieh; Chen, Hsiao-Chin; Chang, Po-shou; Yang, Shu-Mei; Lee, Hsuan-Shu; Dong, Chen-Yuan

    2008-02-01

    Bile is the exocrine secretion of liver and synthesized by hepatocytes. It is drained into duodenum for the function of digestion or drained into gallbladder for of storage. Bile duct obstruction is a blockage in the tubes that carry bile to the gallbladder and small intestine. However, Bile duct ligation results in the changes of bile acids in serum, liver, urine, and feces1, 2. In this work, we demonstrate a novel technique to image this pathological condition by using a newly developed in vivo imaging system, which includes multiphoton microscopy and intravital hepatic imaging chamber. The images we acquired demonstrate the uptake, processing of 6-CFDA in hepatocytes and excretion of CF in the bile canaliculi. In addition to imaging, we can also measure kinetics of the green fluorescence intensity.

  13. [Hypogastric artery ligation. Safety and efficacy of a training program].

    Science.gov (United States)

    García López, A; Martínez Aguirre, R; Hernández Romero, F; Naranjo Gutierrez, A; Montes Reyes, J

    2001-11-01

    Bilateral hypogastric artery ligation is a technique described in the antiquity to restrain the hemorrhage in the gynecological and obstetric surgery. There are few Gineco-obstetricians that dominate the technique, for what intended a training program, in which was to demonstrate their security and effectiveness. We carry out a program where were qualified 14 gineco-obstetricians, theoretical and surgically. Results were analyzed finding an acceptable security with 1.5% of complications and an effectiveness demonstrated when having to the program 92.9% of students that reached the competition. We intend to reply the course in other hospital units, in order to decrease the maternal mortality for hemorrhage obstetric or gynecological.

  14. Seamless Ligation Cloning Extract (SLiCE) cloning method.

    Science.gov (United States)

    Zhang, Yongwei; Werling, Uwe; Edelmann, Winfried

    2014-01-01

    SLiCE (Seamless Ligation Cloning Extract) is a novel cloning method that utilizes easy to generate bacterial cell extracts to assemble multiple DNA fragments into recombinant DNA molecules in a single in vitro recombination reaction. SLiCE overcomes the sequence limitations of traditional cloning methods, facilitates seamless cloning by recombining short end homologies (15-52 bp) with or without flanking heterologous sequences and provides an effective strategy for directional subcloning of DNA fragments from bacterial artificial chromosomes or other sources. SLiCE is highly cost-effective and demonstrates the versatility as a number of standard laboratory bacterial strains can serve as sources for SLiCE extract. We established a DH10B-derived E. coli strain expressing an optimized λ prophage Red recombination system, termed PPY, which facilitates SLiCE with very high efficiencies.

  15. Universal ligation-detection-reaction microarray applied for compost microbes

    Directory of Open Access Journals (Sweden)

    Romantschuk Martin

    2008-12-01

    Full Text Available Abstract Background Composting is one of the methods utilised in recycling organic communal waste. The composting process is dependent on aerobic microbial activity and proceeds through a succession of different phases each dominated by certain microorganisms. In this study, a ligation-detection-reaction (LDR based microarray method was adapted for species-level detection of compost microbes characteristic of each stage of the composting process. LDR utilises the specificity of the ligase enzyme to covalently join two adjacently hybridised probes. A zip-oligo is attached to the 3'-end of one probe and fluorescent label to the 5'-end of the other probe. Upon ligation, the probes are combined in the same molecule and can be detected in a specific location on a universal microarray with complementary zip-oligos enabling equivalent hybridisation conditions for all probes. The method was applied to samples from Nordic composting facilities after testing and optimisation with fungal pure cultures and environmental clones. Results Probes targeted for fungi were able to detect 0.1 fmol of target ribosomal PCR product in an artificial reaction mixture containing 100 ng competing fungal ribosomal internal transcribed spacer (ITS area or herring sperm DNA. The detection level was therefore approximately 0.04% of total DNA. Clone libraries were constructed from eight compost samples. The LDR microarray results were in concordance with the clone library sequencing results. In addition a control probe was used to monitor the per-spot hybridisation efficiency on the array. Conclusion This study demonstrates that the LDR microarray method is capable of sensitive and accurate species-level detection from a complex microbial community. The method can detect key species from compost samples, making it a basis for a tool for compost process monitoring in industrial facilities.

  16. MANAGEMENT OF INTERNAL HEMORRHOID WITH RUBBER BAND LIGATION PROCEDURE

    Directory of Open Access Journals (Sweden)

    I Made Arya Winangun

    2013-10-01

    Full Text Available Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 Hemorrhoid is regarded as the cases most seen in population. The prevalence of this cases about 4,4% with the incidence 12 of 1.000 patient. The current management of hemorrhoid is lifestyle modification, conservative management such as farmacology, minimally invasive treatment and more aggressive therapy using surgical procedure. Rubber band ligation was one of the minimally invasive procedures. This procedure was easy, inexpensive, and can be done outpatient using simple tools without complicated procedure like hemorrhoidectomy. Some studies explained rubber band ligation effectively done in internal hemorrhoid grade II and grade III even this procedure still had minimal complication such as bleeding and unpleasentness /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}

  17. Synthesis and structures of bis-ligated zinc complexes supported by tridentate ketoimines that initiate L-lactide polymerization.

    Science.gov (United States)

    Gerling, Kimberly A; Rezayee, Nomaan M; Rheingold, Arnold L; Green, David B; Fritsch, Joseph M

    2014-11-21

    Eight bis-ligated, homoleptic, zinc complexes were synthesized through the reaction of NNO Schiff base ketoimines bearing varying substituents with diethyl zinc in an inert atmosphere glovebox at room temperature and isolated in 62-95% yield. The complexes were characterized with (1)H, (13)C, and (19)F nuclear magnetic resonance spectroscopy, absorbance spectroscopy, high resolution mass spectrometry, elemental analysis, and single crystal X-ray crystallography. The complexes were shown to adopt distorted octahedral coordination geometry around zinc. The (1)H and (19)F NMR spectra of complexes 1-7 showed stable zinc coordination at 300 K while the effect of steric encumbrance and two trifluoromethyl groups in complex 8 was investigated with variable temperature NMR. The bis-ligated zinc complexes were effective initiators for the ring opening polymerization of L-lactide into poly-L-lactic acid (PLLA). With [L-lac]/[Zn complex] = 50, the bis-ligated zinc complexes yielded percentage conversion of 14-98% with polymerization times varying from 15-1440 min, where the longest reaction times were required when two trifluoromethyl groups were present. The addition of 4-fluorophenol co-catalyst resulted in up to a 5-fold increase in the percentage conversion in toluene solution and up to a 14-fold increase in bulk melt polymerization with reductions in the poly-dispersity index values for the isolated PLLA. Addition of 4-fluorophenol to complex 1 was studied with (1)H and (19)F NMR and appeared to yield an in situ generated zinc alkoxide complex.

  18. Coarctation of the Aorta as a Complication of Surgical Ligation of Patent Ductus Arteriosus in a Premature Infant

    Science.gov (United States)

    Qasim, Amna; Jain, Sunil K.; Jiwani, Amyn K.

    2017-01-01

    Surgical ligation of a patent ductus arteriosus (PDA) is a commonly performed procedure. Complications are infrequent and most commonly include recurrent laryngeal nerve injury and rarely ligation of left pulmonary artery. We report a case of accidental ligation of the descending thoracic aorta leading to a clinically significant coarctation. PMID:28386503

  19. Persistent postpartum haemorrhage after failed arterial ligation: value of pelvic embolisation

    Energy Technology Data Exchange (ETDEWEB)

    Fargeaudou, Yann; Soyer, Philippe; Sirol, Marc; Boudiaf, Mourad; Dahan, Henri; Dref, Olivier le [Hopital Lariboisiere AP-HP et Universite Diderot-Paris 7, Department of Abdominal and Interventional Imaging, Paris (France); Morel, Olivier; Barranger, Emmanuel [Hopital Lariboisiere AP-HP, Department of Obstetrics and Gynecology, Paris (France); Gayat, Etienne; Mebazaa, Alexandre [Hopital Lariboisiere AP-HP, Department of Anesthesiology and Intensive Care Medicine, Paris (France)

    2010-07-15

    To evaluate the role and efficacy of pelvic embolisation in the treatment of persistent postpartum haemorrhage after failed arterial ligation and to identify the complications of this procedure in this specific population. The clinical files and angiographic examinations of 12 consecutive women (mean age 32 years) who were treated with pelvic embolisation because of persistent, severe postpartum haemorrhage after failed arterial ligation were reviewed. Angiography revealed that persistent bleeding was due to incomplete arterial ligation (n = 4) or the presence of newly developed anastomotic routes (n = 8). In 11 women, pelvic embolisation stopped the bleeding. Hysterectomy was needed in one woman with retained placenta. Two complications due to pelvic embolisation, including leg ischaemia and transient sciatic nerve ischaemia, were identified, both after internal iliac artery ligation. In women with persistent postpartum haemorrhage after failed arterial ligation, pelvic embolisation is an effective treatment in most cases. However, embolisation of the anastomotic routes that contribute to persistent bleeding may result in ischaemic complications. These potential complications reaffirm that arterial ligation should not be the favoured option for postpartum haemorrhage and that special care must be given during pelvic embolisation after failed arterial ligation. (orig.)

  20. Recursive directional ligation by plasmid reconstruction allows rapid and seamless cloning of oligomeric genes.

    Science.gov (United States)

    McDaniel, Jonathan R; Mackay, J Andrew; Quiroz, Felipe García; Chilkoti, Ashutosh

    2010-04-12

    This paper reports a new strategy, recursive directional ligation by plasmid reconstruction (PRe-RDL), to rapidly clone highly repetitive polypeptides of any sequence and specified length over a large range of molecular weights. In a single cycle of PRe-RDL, two halves of a parent plasmid, each containing a copy of an oligomer, are ligated together, thereby dimerizing the oligomer and reconstituting a functional plasmid. This process is carried out recursively to assemble an oligomeric gene with the desired number of repeats. PRe-RDL has several unique features that stem from the use of type IIs restriction endonucleases: first, PRe-RDL is a seamless cloning method that leaves no extraneous nucleotides at the ligation junction. Because it uses type IIs endonucleases to ligate the two halves of the plasmid, PRe-RDL also addresses the major limitation of RDL in that it abolishes any restriction on the gene sequence that can be oligomerized. The reconstitution of a functional plasmid only upon successful ligation in PRe-RDL also addresses two other limitations of RDL: the significant background from self-ligation of the vector observed in RDL, and the decreased efficiency of ligation due to nonproductive circularization of the insert. PRe-RDL can also be used to assemble genes that encode different sequences in a predetermined order to encode block copolymers or append leader and trailer peptide sequences to the oligomerized gene.

  1. Efficient DNA ligation in DNA-RNA hybrid helices by Chlorella virus DNA ligase.

    Science.gov (United States)

    Lohman, Gregory J S; Zhang, Yinhua; Zhelkovsky, Alexander M; Cantor, Eric J; Evans, Thomas C

    2014-02-01

    Single-stranded DNA molecules (ssDNA) annealed to an RNA splint are notoriously poor substrates for DNA ligases. Herein we report the unexpectedly efficient ligation of RNA-splinted DNA by Chlorella virus DNA ligase (PBCV-1 DNA ligase). PBCV-1 DNA ligase ligated ssDNA splinted by RNA with kcat ≈ 8 x 10(-3) s(-1) and K(M) DNA ligase produced only 5'-adenylylated DNA with a 20-fold lower kcat and a K(M) ≈ 300 nM. The rate of ligation increased with addition of Mn(2+), but was strongly inhibited by concentrations of NaCl >100 mM. Abortive adenylylation was suppressed at low ATP concentrations (8, leading to increased product yields. The ligation reaction was rapid for a broad range of substrate sequences, but was relatively slower for substrates with a 5'-phosphorylated dC or dG residue on the 3' side of the ligation junction. Nevertheless, PBCV-1 DNA ligase ligated all sequences tested with 10-fold less enzyme and 15-fold shorter incubation times than required when using T4 DNA ligase. Furthermore, this ligase was used in a ligation-based detection assay system to show increased sensitivity over T4 DNA ligase in the specific detection of a target mRNA.

  2. Nitrogen tank

    CERN Document Server

    2006-01-01

    Wanted The technical file about the pressure vessel RP-270 It concerns the Nitrogen tank, 60m3, 22 bars, built in 1979, and installed at Point-2 for the former L3 experiment. If you are in possession of this file, or have any files about an equivalent tank (probably between registered No. RP-260 and -272), please contact Marc Tavlet, the ALICE Glimos.

  3. Comparative Study of Compensatory Liver Regeneration in a Rat Model: Portal Vein Ligation Only versus Sequential Ligation of the Portal Vein and Hepatic Artery

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Soo Young [Dept. of Pathology, Dongnam Institute of Radiological and Medical Sciences, Busan (Korea, Republic of); Jeon, Gyeong Sik [Dept. of Radiology, CHA Bundang Medical Center, College of Medicine, CHA University, Seongnam (Korea, Republic of); Lee, Byung Mo [Dept. of Surgery, Seoul Paik Hospital, Inje University College of Medicine, Seoul (Korea, Republic of)

    2013-04-15

    To compare the volume change and the regenerative capacity between portal vein ligation (embolization) (PVL) and heterochronous PVL with hepatic artery ligation (HAL) in a rodent model. The animals were separated into three groups: group I, ligation of the left lateral and median portal vein branches; group II, completion of PVL, followed by ligation of the same branches of the hepatic artery after 48 h; control group, laparotomy without ligation was performed. Five rats from each group were sacrificed on 1, 3, 5, and 7 days after the operation. Volume change measurement, liver function tests and immunohistochemical analysis were performed. The volume of the nonligated lobe between groups I and II was not significantly different by day 5 and day 7. Mean alanine aminotransferase and total bilirubin levels were significantly higher in group II, while the albumin level was higher in group I. Both c-kit- and MIB-5-positive cells used in the activity detection of regeneration were more prevalent in group I on day 1, 3, and 5, with statistical significance. There was no operation related mortality. PVL alone is safe and effective in compensatory liver regeneration. Performing both PVL and HAL does not confer any additional benefits.

  4. A modified version of the digestion-ligation cloning method for more efficient molecular cloning.

    Science.gov (United States)

    Gao, Song; Li, Yanling; Zhang, Jiannan; Chen, Hongman; Ren, Daming; Zhang, Lijun; An, Yingfeng

    2014-05-15

    Here we describe a modified version of the digestion-ligation approach for efficient molecular cloning. In comparison with the original method, the modified method has the additional steps of gel purification and a second ligation after the first ligation of the linearized vector and DNA insert. During this process, the efficiency and reproducibility could be significantly improved for both stick-end cloning and blunt-end cloning. As an improvement of the very important molecular cloning technique, this method may find a wide range of applications in bioscience and biotechnology.

  5. Real time monitoring of nucleic acids ligation based on molecular beacon

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A novel method has been developed to monitor the nucleic acids ligation process. Molecular beacon was employed here to convert the ligation information into fluorescence signal quickly and quantitatively. This method provides effective and original approach to researching the dynamic ligation process and the interactions between nucleic acids and ligase. An analytical method for T4 DNA ligase based on this way has been built up with a linear detection range from 2.3×10?4 U/mL to 0.23 U/mL. It is rapid and sensitive to detect 2.8×10?5 U T4 DNA ligase in 10 min.

  6. Evaluation of small ligand-protein interaction by ligation reaction with DNA-modified ligand.

    Science.gov (United States)

    Sugita, Rie; Mie, Masayasu; Funabashi, Hisakage; Kobatake, Eiry

    2010-01-01

    A method for the evaluation of interactions between protein and ligand using DNA-modified ligands, including signal enhancement of the DNA ligation reactions, is described. For proof of principle, a DNA probe modified by biotin was used. Two DNA probes were prepared with complementary sticky-ends. While one DNA probe was modified at the 5'-end of the sticky-end, the other was not modified. The probes could be ligated together by T4 DNA ligase along the strand without biotin modification. However, in the presence of streptavidin or anti-biotin Fab, the ligation reaction joining the two probes could not occur on either strand.

  7. Efficient DNA ligation in DNA–RNA hybrid helices by Chlorella virus DNA ligase

    OpenAIRE

    Lohman, Gregory J. S.; Zhang, Yinhua; Zhelkovsky, Alexander M.; Cantor, Eric J.; Evans, Thomas C.

    2013-01-01

    Single-stranded DNA molecules (ssDNA) annealed to an RNA splint are notoriously poor substrates for DNA ligases. Herein we report the unexpectedly efficient ligation of RNA-splinted DNA by Chlorella virus DNA ligase (PBCV-1 DNA ligase). PBCV-1 DNA ligase ligated ssDNA splinted by RNA with kcat ≈ 8 x 10−3 s−1 and KM < 1 nM at 25°C under conditions where T4 DNA ligase produced only 5′-adenylylated DNA with a 20-fold lower kcat and a KM ≈ 300 nM. The rate of ligation increased with addition of M...

  8. Sequential changes in redox status and nitric oxide synthases expression in the liver after bile duct ligation.

    Science.gov (United States)

    Vázquez-Gil, M José; Mesonero, M José; Flores, Olga; Criado, Manuela; Hidalgo, Froilán; Arévalo, Miguel A; Sánchez-Rodríguez, Angel; Tuñón, M Jesús; López-Novoa, José M; Esteller, A

    2004-06-25

    Bile duct ligation (BDL) in rats induces portal fibrosis. This process has been linked to changes in the oxidative state of the hepatic cells and in the production of nitric oxide. Our objective was to find possible temporal connections between hepatic redox state, NO synthesis and liver injury. In this work we have characterized hepatic lesions 17 and 31 days after BDL and determined changes in hepatic function, oxidative state, and NO production. We have also analyzed the expression and localization of inducible NO synthase (NOS2) and constitutive NO synthase (NOS3). After 17 and 31 days from ligature, lipid peroxidation is increased and both plasma concentration and biliary excretion of nitrite+nitrate are rised. 17 days after BDL both NOS2 and NOS3 are expressed intensely and in the same regions. 31 days after BDL, the expression of NOS2 remains elevated and is localized mostly in preserved hepatocytes in portal areas and in neighborhoods of centrolobulillar vein. NOS3 is localized in vascular regions of portal spaces and centrolobulillar veins and in preserved sinusoids and although its expression is greater than in control animals (34%), it is clearly lower (50%) than 17 days after BDL. The time after BDL is crucial in the study of NO production, intrahepatic localization of NOS isoforms expression, and cell type involved, since all these parameters change with time. BDL-induced, peroxidation and fibrosis are not ligated by a cause-effect relationship, but rather they both seem to be the consequence of common inductors.

  9. Expanded utility of the native chemical ligation reaction.

    Science.gov (United States)

    Yeo, Dawn S Y; Srinivasan, Rajavel; Chen, Grace Y J; Yao, Shao Q

    2004-10-04

    The post-genomic era heralds a multitude of challenges for chemists and biologists alike, with the study of protein functions at the heart of much research. The elucidation of protein structure, localization, stability, post-translational modifications, and protein interactions will steadily unveil the role of each protein and its associated biological function in the cell. The push to develop new technologies has necessitated the integration of various disciplines in science. Consequently, the role of chemistry has never been so profound in the study of biological processes. By combining the strengths of recombinant DNA technology, protein splicing, organic chemistry, and the chemoselective chemistry of native chemical ligation, various strategies have been successfully developed and applied to chemoselectively label proteins, both in vitro and in live cells, with biotin, fluorescent, and other small molecule probes. The site-specific incorporation of molecular entities with unique chemical functionalities in proteins has many potential applications in chemical and biological studies of proteins. In this article, we highlight recent progress of these strategies in several areas related to proteomics and chemical biology, namely, in vitro and in vivo protein biotinylation, protein microarray technologies for large-scale protein analysis, and live-cell bioimaging.

  10. Laparoscopic ligation of varicoceles: an anatomically superior operation.

    Science.gov (United States)

    al-Shareef, Z. H.; Koneru, S. R.; al-Tayeb, A.; Shehata, Z. M.; Aly, T. F.; Basyouni, A.

    1993-01-01

    Since December 1991, 25 consecutive symptomatic male patients with 26 varicoceles were treated by laparoscopic ligation of internal spermatic veins under general anaesthesia. Twenty-one patients had either scrotal discomfort or painful swelling and four patients presented with infertility. The mean follow-up period is 5 months (range 3 weeks to 9 months). The procedure has provided a satisfactory outcome in 19 out of 21 patients (90.5%) with scrotal symptoms. Of the four patients presenting with infertility due to oligospermia, three had significantly elevated sperm counts at 3 months which resulted in one pregnancy. So far there has been no recurrence of the varicocele. The main potential advantage of the laparoscopic approach is better visualisation of the anatomy, especially the testicular artery and the collateral venous circulation at the level of the internal inguinal ring. In addition to being less invasive with implied benefits, the endoscopic procedure has enabled identification of multiple veins in 22 out of 26 (84.6%) varicoceles in our series. PMID:8166797

  11. Molecular and structural characterization of dissolved organic matter from the deep ocean by FTICR-MS, including hydrophilic nitrogenous organic molecules

    Science.gov (United States)

    Reemtsma, T.; These, A.; Linscheid, M.; Leenheer, J.; Spitzy, A.

    2008-01-01

    Dissolved organic matter isolated from the deep Atlantic Ocean and fractionated into a so-called hydrophobic (HPO) fraction and a very hydrophilic (HPI) fraction was analyzed for the first time by Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) to resolve the molecular species, to determine their exact masses, and to calculate their molecular formulas. The elemental composition of about 300 molecules was identified. Those in the HPO fraction (14C age of 5100 year) are very similar to much younger freshwater fulvic acids, but less aromatic and more oxygenated molecules are more frequent. This trend continues toward the HPI fraction and may indicate biotic and abiotic aging processes that this material experienced since its primary production thousands of years ago. In the HPI fraction series of nitrogenous molecules containing one, two, or three nitrogens were identified by FTICR-MS. Product ion spectra of the nitrogenous molecules suggest that the nitrogen atoms in these molecules are included in the (alicyclic) backbone of these molecules, possibly in reduced form. These mass spectrometric data suggest that a large set of stable fulvic acids is ubiquitous in all aquatic compartments. Although sources may differ, their actual composition and structure appears to be quite similar and largely independent from their source, because they are the remainder of intensive oxidative degradation processes. ?? 2008 American Chemical Society.

  12. Chemoselective modifications for the traceless ligation of thioamide-containing peptides and proteins.

    Science.gov (United States)

    Wang, Yanxin J; Szantai-Kis, D Miklos; Petersson, E James

    2016-07-14

    Thioamides are single-atom substitutions of canonical amide bonds, and have been proven to be versatile and minimally perturbing probes in protein folding studies. Previously, our group showed that thioamides can be incorporated into proteins by native chemical ligation (NCL) with Cys as a ligation handle. In this study, we report the expansion of this strategy into non-Cys ligation sites, utilizing radical initiated desulfurization to "erase" the side chain thiol after ligation. The reaction exhibited high chemoselectivity against thioamides, which can be further enhanced with thioacetamide as a sacrificial scavenger. As a proof-of-concept example, we demonstrated the incorporation of a thioamide probe into a 56 amino acid protein, the B1 domain of Protein G (GB1). Finally, we showed that the method can be extended to β-thiol amino acid analogs and selenocysteine.

  13. Chemical ligation methods for the tagging of DNA-encoded chemical libraries.

    Science.gov (United States)

    Keefe, Anthony D; Clark, Matthew A; Hupp, Christopher D; Litovchick, Alexander; Zhang, Ying

    2015-06-01

    The generation of DNA-encoded chemical libraries requires the unimolecular association of multiple encoding oligonucleotides with encoded chemical entities during combinatorial synthesis processes. This has traditionally been achieved using enzymatic ligation. We discuss a range of chemical ligation methods that provide alternatives to enzymatic ligation. These chemical ligation methods include the generation of modified internucleotide linkages that support polymerase translocation and other modified linkages that while not supporting the translocation of polymerases can also be used to generate individual cDNA molecules containing encoded chemical information specifying individual library members. We also describe which of these approaches have been successfully utilized for the preparation of DNA-encoded chemical libraries and those that were subsequently used for the discovery of inhibitors.

  14. Heated oligonucleotide ligation assay (HOLA): an affordable single nucleotide polymorphism assay.

    Science.gov (United States)

    Black, W C; Gorrochotegui-Escalante, N; Duteau, N M

    2006-03-01

    Most single nucleotide polymorphism (SNP) detection requires expensive equipment and reagents. The oligonucleotide ligation assay (OLA) is an inexpensive SNP assay that detects ligation between a biotinylated "allele-specific detector" and a 3' fluorescein-labeled "reporter" oligonucleotide. No ligation occurs unless the 3' detector nucleotide is complementary to the SNP nucleotide. The original OLA used chemical denaturation and neutralization. Heated OLA (HOLA) instead uses a thermal stable ligase and cycles of denaturing and hybridization for ligation and SNP detection. The cost per genotype is approximately US$1.25 with two-allele SNPs or approximately US$1.75 with three-allele SNPs. We illustrate the development of HOLA for SNP detection in the Early Trypsin and Abundant Trypsin loci in the mosquito Aedes aegypti (L.) and at the a-glycerophosphate dehydrogenase locus in the mosquito Anopheles gambiae s.s.

  15. Common Carotid Artery Ligation to Minimize Blood Loss During Oral and Maxillofacial Surgery.

    Science.gov (United States)

    Goodman, Alice E; Goodman, Andrew R

    2016-09-01

    Oral and maxillofacial surgery in veterinary medicine carries the risk of severe hemorrhage due to the great vascular supply of the head. Temporary hemostasis can be achieved with the application of pressure or hemostatic agents, but more definitive treatment may be needed to ensure bleeding will not resume once the patient is awake and normotensive. (1 , 2) Actively bleeding vessels encountered during maxillofacial surgery may be inaccessible, and vessels may recoil into bone, sometimes preventing definitive ligation. These scenarios may require ligation of the common carotid artery. (1) The purpose of this paper is to describe how to perform ligation of the common carotid artery in a step-by-step fashion. Both temporary and permanent ligation techniques are described.

  16. Interrupting Rivaling Access-flow with Nonsurgical Image-guided ligation: the "IRANI" Procedure.

    Science.gov (United States)

    Cui, Jie; Freed, Robert; Liu, Fengyong; Irani, Zubin

    2015-01-01

    The presence of collateral veins is one of the most common causes of fistula failure to mature. The traditional approach to eliminate collateral vessel flow is coil embolization under fluoroscopy or surgical cut down and branch vessel ligation. However, both approaches are expensive and time consuming. Here, we described an image-guided nonsurgical method to ligate collateral veins. The collateral veins were ligated using Hawkins-Akins needle under ultrasound guidance. The average time for one ligation procedure was 17 minutes. There was a significant increase of blood flow in the venous outflow postligation procedure. Four weeks postprocedure ultrasound demonstrated occlusion of the target vessels. This procedure was well tolerated without major complications. In summary, the novel procedure described here offers an image-guided nonsurgical approach for collateral vein occlusion.

  17. Generating site-specifically modified proteins via a versatile and stable nucleophilic carbon ligation.

    Science.gov (United States)

    Kudirka, Romas; Barfield, Robyn M; McFarland, Jesse; Albers, Aaron E; de Hart, Gregory W; Drake, Penelope M; Holder, Patrick G; Banas, Stefanie; Jones, Lesley C; Garofalo, Albert W; Rabuka, David

    2015-02-19

    There is a need for facile chemistries that allow for chemo- and regioselectivity in bioconjugation reactions. To address this need, we are pioneering site-specific bioconjugation methods that use formylglycine as a bioorthogonal handle on a protein surface. Here we introduce aldehyde-specific bioconjugation chemistry, the trapped-Knoevenagel ligation. The speed and stability of the trapped-Knoevenagel ligation further advances the repertoire of aldehyde-based bioconjugations and expands the toolbox for site-specific protein modifications. The trapped-Knoevenagel ligation reaction can be run at near neutral pH in the absence of catalysts to produce conjugates that are stable under physiological conditions. Using this new ligation, we generated an antibody-drug conjugate that demonstrates excellent efficacy in vitro and in vivo.

  18. Nonenzymatic ligation of an RNA oligonucleotide analyzed by atomic force microscopy.

    Science.gov (United States)

    Pino, Samanta; Biasiucci, Mariano; Scardamaglia, Mattia; Gigli, Giuseppe; Betti, Maria Grazia; Mariani, Carlo; Di Mauro, Ernesto

    2011-05-19

    The products of ligation reaction of a 24 nucleotides long PolyA RNA adsorbed on mica were observed by atomic force microscopy. The occurrence of oligonucleotides at different degrees of polymerization has been quantitatively studied before and after ligation reaction. The microscopy images at the nanoscale show that nonenzymatic ligation of pristine RNA monomers results in the formation of supramolecular aggregates, with prevalence of dimers and tetramers. Analytical conditions were defined allowing the identification, the quantitative evaluation, and their distribution after ligation reaction, also providing an estimate of the degree of hydration of the objects. Such investigation is of particular biological relevance and provides the simplest yet model system for direct investigation of RNA reactions by advanced microscopy.

  19. Divergent and convergent synthesis of GalNAc-conjugated dendrimers using dual orthogonal ligations.

    Science.gov (United States)

    Thomas, Baptiste; Pifferi, Carlo; Daskhan, Gour Chand; Fiore, Michele; Berthet, Nathalie; Renaudet, Olivier

    2015-12-21

    The synthesis of glycodendrimers remains a challenging task. In this paper we propose a protocol based on both oxime ligation (OL) to combine cyclopeptide repeating units as the dendritic core and the copper(i)-catalyzed azide-alkyne cycloaddition (CuAAC) to conjugate peripheral α and β propargylated GalNAc. By contrast with the oxime-based iterative protocol reported in our group, our current strategy can be used in both divergent and convergent routes with similar efficiency and the resulting hexadecavalent glycodendrimers can be easily characterized compared to oxime-linked analogues. A series of glycoconjugates displaying four or sixteen copies of both α and β GalNAc have been prepared and their ability to inhibit the adhesion of the soybean agglutinin (SBA) lectin to polymeric-GalNAc immobilized on microtiter plates has been evaluated. As was anticipated, the higher inhibitory effect (IC50 = 0.46 μM) was measured with the structure displaying αGalNAc with the higher valency (compound 13), which demonstrates that the binding properties of these glycoconjugates are strongly dependent on the orientation and distribution of the GalNAc units.

  20. Genome assembly with in vitro proximity ligation data and whole-genome triplication in lettuce.

    Science.gov (United States)

    Reyes-Chin-Wo, Sebastian; Wang, Zhiwen; Yang, Xinhua; Kozik, Alexander; Arikit, Siwaret; Song, Chi; Xia, Liangfeng; Froenicke, Lutz; Lavelle, Dean O; Truco, María-José; Xia, Rui; Zhu, Shilin; Xu, Chunyan; Xu, Huaqin; Xu, Xun; Cox, Kyle; Korf, Ian; Meyers, Blake C; Michelmore, Richard W

    2017-04-12

    Lettuce (Lactuca sativa) is a major crop and a member of the large, highly successful Compositae family of flowering plants. Here we present a reference assembly for the species and family. This was generated using whole-genome shotgun Illumina reads plus in vitro proximity ligation data to create large superscaffolds; it was validated genetically and superscaffolds were oriented in genetic bins ordered along nine chromosomal pseudomolecules. We identify several genomic features that may have contributed to the success of the family, including genes encoding Cycloidea-like transcription factors, kinases, enzymes involved in rubber biosynthesis and disease resistance proteins that are expanded in the genome. We characterize 21 novel microRNAs, one of which may trigger phasiRNAs from numerous kinase transcripts. We provide evidence for a whole-genome triplication event specific but basal to the Compositae. We detect 26% of the genome in triplicated regions containing 30% of all genes that are enriched for regulatory sequences and depleted for genes involved in defence.

  1. Comparison of frictional resistance of esthetic and semi-esthetic self-ligating brackets

    Directory of Open Access Journals (Sweden)

    M S Kannan

    2015-01-01

    Full Text Available Aim: The frictional resistance encountered during sliding mechanics has been well established in the orthodontic literature, and it consists of complex interactions between the bracket, archwire, and method of ligation the claim of reduced friction with self-ligating brackets is often cited as a primary advantage over conventional brackets. This study was done to compare and evaluate the frictional forces generated between fully esthetic brackets and semi-aesthetic self-ligating brackets, which are of passive form and SEM (scanning electron microscope study of the Brackets after Frictional evaluation. Materials and Methods: Two types of self-ligating esthetic brackets, Damon clear (Ormco made of fully ceramic and Opal (Ultradent Products, USA and, Two types of self-ligating semi-esthetic brackets, Clarity SL (3M Unitek and Damon 3 (Ormco both of which are made of ceramic with metal slot. Arch wires with different dimensions and quality 17 × 25, 19 × 25 Titanium Molybdenum Alloy (TMA and 17 × 25, 19 × 25 stainless steel that came from plain strands of wire were used for frictional comparison test. The brackets used in this study had 0.022 × 0.028 inch slot. Results: The statistical tests showed significantly smaller amount of kinetic frictional forces is generated by Damon 3 (semi-esthetic self-ligating brackets. For each wire used, Damon 3 displayed significantly lower frictional forces (P ≤ 0.05 than any of the self-ligating system, followed by Opal (fully esthetic self-ligating brackets which generated smaller amount of frictional forces but relatively on the higher side when compared with Damon 3. Damon clear (fully esthetic self-ligating brackets generated the maximum amount of kinetic forces with all types of wire dimensions and properties when compared to the other three types of self-ligating system. Clarity SL (semi-esthetic self-ligating brackets generated smaller amount of frictional forces when compared with Damon clear and

  2. Infrared spectra and electronic structure calculations for NN complexes with U, UN, and NUN in solid argon, neon, and nitrogen.

    Science.gov (United States)

    Andrews, Lester; Wang, Xuefeng; Gong, Yu; Kushto, Gary P; Vlaisavljevich, Bess; Gagliardi, Laura

    2014-07-17

    Reactions of laser-ablated U atoms with N2 molecules upon codeposition in excess argon or neon at 4 K gave intense NUN and weak UN absorptions. Annealing produced progressions of new absorptions for the UN2(N2)1,2,3,4,5 and UN(N2)1,2,3,4,5,6 complexes. The neon-to-argon matrix shift decreases with increasing NN ligation and therefore the number of noble gas atoms left in the primary coordination sphere around the NUN molecule. Small matrix shifts are observed when the secondary coordination layers around the primary UN2(N2)1,2,3,4,5 and UN(N2)1,2,3,4,5,6 complexes are changed from neon-to-argon to nitrogen. Electronic structure, energy, and frequency calculations provide support for the identification of these complexes and the characterization of the N≡U≡N and U≡N core molecules as terminal uranium nitrides. Codeposition of U with pure nitrogen produced the saturated U(NN)7 complex, which UV irradiation converted to the NUN(NN)5 complex with slightly lower frequencies than found in solid argon.

  3. Identification and characterization of the Rhizobium meliloti ntrC gene: R. meliloti has separate regulatory pathways for activation of nitrogen fixation genes in free-living and symbiotic cells.

    OpenAIRE

    Szeto, W W; Nixon, B T; Ronson, C W; Ausubel, F M

    1987-01-01

    We show here that Rhizobium meliloti, the nitrogen-fixing endosymbiont of alfalfa (Medicago sativa), has a regulatory gene that is structurally homologous to previously characterized ntrC genes in enteric bacteria. DNA sequence analysis showed that R. meliloti ntrC is homologous to previously sequenced ntrC genes from Klebsiella pneumoniae and Bradyrhizobium sp. (Parasponia) and that an ntrB-like gene is situated directly upstream from R. meliloti ntrC. Similar to its counterparts in K. pneum...

  4. Can 5-aminosalicylic acid suppository decrease the pain after rectal band ligation?

    Institute of Scientific and Technical Information of China (English)

    Burcak Kayhan; Digdem Ozer; Meral Akdogan; Ersan Ozaslan; Osman Yuksel

    2008-01-01

    AIM: To investigate the effect of 5-aminosalicylic acid (5-ASA) suppositories on rectal band ligation-induced pain.METHODS: Sixty patients were randomized into two treatment groups.RESULTS: Our results showed that there was no difference between 5-ASA suppository group and the control group for pain control.CONCLUSION: 5-ASA may be an alternative treatment for hemorrhoids; however, it does not affect the rectal band ligation-induced pain.

  5. Effect of ZVAD-fmk on hepatocyte apoptosis after bile duct ligation in rat

    Institute of Scientific and Technical Information of China (English)

    Shyr-Ming Sheen-Chen; Hsin-Tsung Ho; Wei-Jen Chen; Hock-Liew Eng

    2005-01-01

    AIM: Retention and accumulation of toxic hydrophobic bile salts within hepatocyte may cause hepatocyte toxicity by inducing apoptosis. Apoptosis is a pathway of cell death orchestrated by a family of proteases called caspases. Z-ValAla-Asp (OMe)-fluoromethyl ketone (ZVAD-fmk) is a cellpermeable irreversible inhibitor of caspase. The purpose of this study was to evaluate the possible effect of ZVAD-fmk on hepatocyte apoptosis after bile duct ligation in the rat.METHODS: Male Sprague-Dawley rats, weighing 250-300 g,were randomized to five groups of five rats each. Group 1 underwent common bile duct ligation and simultaneous treatment with ZVAD-fmk (dissolved in dimethylsulfoxide (DMSO)). Group 2 underwent common bile duct ligation and simultaneous treatment with Z-Phe-Ala-fluoromethyl ketone ( ZFA-fmk, dissolved in DMSO). Group 3 underwent sham operation and simultaneous treatment with the same amount of DMSO. Group 4 underwent sham operation and simultaneous treatment with the same amount of normal saline. Group 5 underwent common bile duct ligation without other manipulation. After three days, liver tissue was harvested for histopathologic analysis and measurements of apoptosis.RESULTS: When compared with sham operation, common bile duct ligation significantly increased hepatocyte apoptosis (P= 0.008) and ductular proliferation (P= 0.007).ZVAD-fmk significantly diminished the increased hepatocyte apoptosis and ductular proliferation after common bile duct ligation (P = 0.008 and P = 0.007, respectively). ZFA did not show the same effects.CONCLUSION: Hepatocyte apoptosis and ductular proliferation significantly increased after common bile duct ligation. ZVAD-fmk effectively diminished the increased hepatocyte apoptosis and ductular proliferation after common bile duct ligation, whereas ZFA-fmk did not.

  6. Is Previous Tubal Ligation a Risk Factor for Hysterectomy because of Abnormal Uterine Bleeding?

    OpenAIRE

    Sanam Moradan; Raheb Gorbani

    2012-01-01

    Objectives: Post tubal ligation syndrome (PTLS) is a term used to describe a variety of post tubal ligation side effects or symptoms. These include increased menstrual bleeding and hysterectomy. Whether or not post tubal syndrome is a real entity, it has been a subject of controversy in the medical literature for decades. Numerous studies have reported conflicting conclusions about these symptoms. In this study the incidence of hysterectomy for bleeding disorders among sterilized women was co...

  7. Cross-catalytic peptide nucleic acid (PNA) replication based on templated ligation

    DEFF Research Database (Denmark)

    Singhal, Abhishek; Nielsen, Peter E

    2014-01-01

    We report the first PNA self-replicating system based on template directed cross-catalytic ligation, a process analogous to biological replication. Using two template PNAs and four pentameric precursor PNAs, all four possible carbodiimide assisted amide ligation products were detected and identif...... oligonucleotides are feasible, thereby strengthening the foundation for the discussion of a possible role for PNA (like) genetic material in the prebiotic evolution of life and lay the ground for further studies into evolution of such potentially prebiotic systems....

  8. Superficial Dorsal Vein Injury/Thrombosis Presenting as False Penile Fracture Requiring Dorsal Venous Ligation

    Directory of Open Access Journals (Sweden)

    Arash Rafiei, MD

    2014-12-01

    Conclusion: Early exploration of patients with suspected penile fracture provides excellent results with maintenance of erectile function. Also, in the setting of dorsal vein thrombosis, ligation preserves the integrity of the penile tissues and avoids unnecessary complications from conservative management. Rafiei A, Hakky TS, Martinez D, Parker J, and Carrion R. Superficial dorsal vein injury/thrombosis presenting as false penile fracture requiring dorsal venous ligation. Sex Med 2014;2:182–185.

  9. Synthesis of cysteine-rich peptides by native chemical ligation without use of exogenous thiols.

    Science.gov (United States)

    Tsuda, Shugo; Yoshiya, Taku; Mochizuki, Masayoshi; Nishiuchi, Yuji

    2015-04-03

    Native chemical ligation (NCL) performed without resorting to the use of thiol additives was demonstrated to be an efficient and effective procedure for synthesizing Cys-rich peptides. This method using tris(2-carboxyethyl)phosphine (TCEP) as a reducing agent facilitates the ligation reaction even at the Thr-Cys or Ile-Cys site and enables one-pot synthesis of Cys-rich peptides throughout NCL and oxidative folding.

  10. Meta-analysis: banding ligation and medical interventions for the prevention of rebleeding from oesophageal varices

    DEFF Research Database (Denmark)

    Thiele, Maja; Krag, A; Rohde, Ulrich;

    2012-01-01

    In patients with oesophageal varices, the combination of endoscopic variceal ligation (EVL) and medical therapy is recommended as standard of care for prevention of rebleeding. The results of previous meta-analyses on this topic are equivocal.......In patients with oesophageal varices, the combination of endoscopic variceal ligation (EVL) and medical therapy is recommended as standard of care for prevention of rebleeding. The results of previous meta-analyses on this topic are equivocal....

  11. Cholestasis progression effects on long-term memory in bile duct ligation rats

    Directory of Open Access Journals (Sweden)

    Nasrin Hosseini

    2014-01-01

    Full Text Available Background : There is evidence that cognitive functions are affected by some liver diseases such as cholestasis. Bile duct ligation induces cholestasis as a result of impaired liver function and cognition. This research investigates the effect of cholestasis progression on memory function in bile duct ligation rats. Materials and Methods: Male Wistar rats were randomly divided into five groups, which include: control group for BDL-7, control group for BDL-21, sham group (underwent laparotomy without bile duct ligation, BDL-7 group (7 days after bile duct ligation, and BDL-21 group (21 days after bile duct ligation. Step-through passive avoidance test was employed to examine memory function. In all groups, short-term (7 days after foot shock and long-term memories (21 days after foot shock were assessed. Results: Our results showed that liver function significantly decreased with cholestasis progression (P < 0.01. Also our findings indicated BDL-21 significantly impaired acquisition time (P < 0.05. Memory retrieval impaired 7 (P < 0.05 and 21 days (P < 0.001 after foot shock in BDL-7 and BDL-21 groups, respectively. Conclusion: Based on these findings, liver function altered in cholestasis and memory (short-term and long-term memory impaired with cholestasis progression in bile duct ligation rats. Further studies are needed to better insight the nature of progression of brain damage in cholestatic disease.

  12. An efficient ligation reaction promoted by a Varkud Satellite ribozyme with extended 5'- and 3'-termini.

    Science.gov (United States)

    Jones, F D; Ryder, S P; Strobel, S A

    2001-12-15

    The Neurospora Varkud Satellite (VS) RNA is capable of promoting a reversible self-cleavage reaction important for its replication pathway. In vivo the VS RNA performs a cis-cleavage reaction to generate monomeric length transcripts that are subsequently ligated to produce circular VS RNA. The predominant form of VS RNA observed in vivo is the closed circular form, though minimal VS ribozyme self-cleavage constructs lack detectable ligation activity. MFOLD analysis of the entire VS RNA sequence revealed an extended region 5' and 3' of the minimal self-cleaving region that could anneal to form a complementary helix, which we have termed helix 7. In full-length VS RNA, this helix appears to span over 40 bp of sequence and brings the 5'- and 3'-ends of the RNA into proximity for the ligation reaction. Here we report a variant of the VS ribozyme with an extended 5'- and 3'-terminus capable of forming a truncated helix 7 that promotes the ligation reaction in vitro. Through mutation and selection of this RNA we have identified a ribozyme containing two point mutations in the truncated helix 7 that ligates with >70% efficiency. These results show that an additional helical element absent in current VS ribozyme constructs is likely to be important for the ligation activity of VS RNA.

  13. Electrochemical detection of point mutation based on surface ligation reaction and biometallization.

    Science.gov (United States)

    Zhang, Peng; Chu, Xia; Xu, Xiangmin; Shen, Guoli; Yu, Ruqin

    2008-05-15

    A highly sensitive electrochemical method for point mutation detection based on surface enzymatic ligation reaction and biometallization is demonstrated. In this method the surface-immobilized allele-specific probe, complementary to the mutant target, undergoes allele-specific ligation with the 5'-phosphorylated ligation probe in the presence of the mutant oligonucleotide target and E. coli DNA ligase. If there is an allele mismatch, no ligation takes place. After thermal treatment at 90 degrees C, the formed duplex melts apart, which merely allows the ligation product to remain on the electrode surface. Then, biotinylated detection probes hybridize with the ligation product. With the binding of streptavidin-alkaline phosphatase (SA-ALP) to the biotinylated probes, a non-reductive substrate of alkaline phosphatase, ascorbic acid 2-phosphate (AA-P), can be converted into ascorbic acid (AA) at the electrode surface. Silver ions in solution are then reduced by AA, resulting in the deposition of silver metal onto the electrode surface. Linear sweep voltammetry (LSV) is used to detect the amount of deposited silver. The proposed approach has been successfully implemented for the identification of single base mutation in codon 12 of K-ras oncogene target with a detection limit of 80fM, demonstrating that this method provides a highly specific, sensitive and cost-efficient approach for point mutation detection.

  14. Insights into the mechanism and catalysis of the native chemical ligation reaction.

    Science.gov (United States)

    Johnson, Erik C B; Kent, Stephen B H

    2006-05-24

    Native chemical ligation of unprotected peptide segments involves reaction between a peptide-alpha-thioester and a cysteine-peptide, to yield a product with a native amide bond at the ligation site. Peptide-alpha-thioalkyl esters are commonly used because of their ease of preparation. These thioalkyl esters are rather unreactive so the ligation reaction is catalyzed by in situ transthioesterification with thiol additives. The most common thiol catalysts used to date have been either a mixture of thiophenol/benzyl mercaptan, or the alkanethiol MESNA. Despite the use of these thiol catalysts, ligation reactions typically take 24-48 h. To gain insight into the mechanism of native chemical ligaton and in order to find a better catalyst, we investigated the use of a number of thiol compounds. Substituted thiophenols with pK(a) > 6 were found to best combine the ability to exchange rapidly and completely with thioalkyl esters, and to then act as effective leaving groups in reaction of the peptide-thioester with the thiol side chain of a cysteine-peptide. A highly effective and practical catalyst was (4-carboxylmethyl)thiophenol ('MPAA'), a nonmalodorous, water-soluble thiol. Use of MPAA gave an order of magnitude faster reaction in model studies of native chemical ligation and in the synthesis of a small protein, turkey ovomucoid third domain (OMTKY3). MPAA should find broad use in native chemical ligation and in the total synthesis of proteins.

  15. Effects of 2'-O-methyl nucleotide on ligation capability of T4 DNA ligase.

    Science.gov (United States)

    Zhao, Bin; Tong, Zhaoxue; Zhao, Guojie; Mu, Runqing; Shang, Hong; Guan, Yifu

    2014-09-01

    To further understand the ligation mechanism, effects of 2'-O-methyl nucleotide (2'-OMeN) on the T4 DNA ligation efficiency were investigated. Fluorescence resonance energy transfer assay was used to monitor the nick-joining process by T4 DNA ligase. Results showed that substitutions at 5'- and 3'-ends of the nick decreased the ligation efficiency by 48.7% ± 6.7% and 70.6% ± 4.0%, respectively. Substitutions at both 5'- and 3'-ends decreased the ligation efficiency by 76.6% ± 1.3%. Corresponding kinetic parameters, Vmax, Km, and kcat, have been determined in each case by using the Michaelis-Menten equation. The kinetic data showed that the 2'-OMeN substitutions reduced the maximal initial velocity and increased the Michaelis constant of T4 DNA ligase. Mismatches at 5'- and 3'-ends of the nick have also shown different influences on the ligation. Results here showed that the sugar pucker conformation at 3'-end impairs the ligation efficiency more profoundly than that at 5'-end. Different concentrations of Mg(2+), Ca(2+), K(+), Na(+), and ATP were also demonstrated to affect the T4 DNA ligase activity. These results enriched our knowledge about the effects of 2'-OMeN substitutions on the T4 DNA ligase.

  16. Realizing Serine/Threonine Ligation: Scope and Limitations and Mechanistic Implication Thereof

    Directory of Open Access Journals (Sweden)

    Clarence T. T. Wong

    2014-05-01

    Full Text Available Serine/Threonine ligation (STL has emerged as an alternative tool for protein chemical synthesis, bioconjugations as well as macrocyclization of peptides of various sizes. Owning to the high abundance of Ser/Thr residues in natural peptides and proteins, STL is expected to find a wide range of applications in chemical biology research. Herein, we have fully investigated the compatibility of the serine/threonine ligation strategy for X-Ser/Thr ligation sites, where X is any of the 20 naturally occurring amino acids. Our studies have shown that 17 amino acids are suitable for ligation, while Asp, Glu, and Lys are not compatible. Among the working 17 C-terminal amino acids, the retarded reaction resulted from the bulky β-branched amino acid (Thr, Val and Ile is not seen under the current ligation condition. We have also investigated the chemoselectivity involving the amino group of the internal lysine which may compete with the N-terminal Ser/Thr for reaction with the C-terminal salicylaldehyde (SAL ester aldehyde group. The result suggested that the free internal amino group does not adversely slow down the ligation rate.

  17. The CCTL (Cpf1-assisted Cutting and Taq DNA ligase-assisted Ligation) method for efficient editing of large DNA constructs in vitro.

    Science.gov (United States)

    Lei, Chao; Li, Shi-Yuan; Liu, Jia-Kun; Zheng, Xuan; Zhao, Guo-Ping; Wang, Jin

    2017-01-23

    As Cpf1 cleaves double-stranded DNA in a staggered way, it can be used in DNA assembly. However, the Cpf1 cleavage was found to be inaccurate, which may cause errors in DNA assembly. Here, the Cpf1 cleavage sites were precisely characterized, where the cleavage site on the target strand was around the 22nd base relative to the protospacer adjacent motif site, but the cleavage on the non-target strand was affected by the spacer length. When the spacer length was 20 nt or longer, Cpf1 mainly cleaved around the 14th and the 18th bases on the non-target strand; otherwise, with a shorter spacer (i.e. 17-19 nt), Cpf1 mainly cleaved after the 14th base, generating 8-nt sticky ends. With this finding, Cpf1 with a 17-nt spacer crRNA were employed for in vitro substitution of the actII-orf4 promoter in the actinorhodin biosynthetic cluster with a constitutively expressing promoter. The engineered cluster yielded more actinorhodin and produced actinorhodin from an earlier phase. Moreover, Taq DNA ligase was further employed to increase both the ligation efficiency and the ligation accuracy of the method. We expect this CCTL (Cpf1-assisted Cutting and Taq DNA ligase-mediated Ligation) method can be widely used in in vitro editing of large DNA constructs.

  18. Integrin Ligation Results in Nephrin Tyrosine Phosphorylation In Vitro.

    Directory of Open Access Journals (Sweden)

    Rakesh Verma

    Full Text Available Nephrin is expressed at the basolateral aspect of podocytes and is an important signaling protein at the glomerular slit diaphragm. In vitro studies have demonstrated that Nephrin phosphorylation-dependent signaling is able to assemble a protein complex that is able to polymerize actin. However, proximal signaling events that result in nephrin tyrosine phosphorylation are not well understood. Nephrin deletion in mice and human nephrin mutations result in developmental failure of the podocyte intercellular junction resutling in proteinuria. This has been presumed to be due to a failure to respond to an external polarized cue in the absence of nephrin or a failure to transduce an outside-in signal in patients with nephrin mutations. The nephrin extracellular domain binds to itself or neph1 across the foot process intercellular junction. Nephrin is tyrosine phosphorylation-silent in healthy glomeruli when presumably the nephrin extracellular domain is in an engaged state. These observations raise the possibility of an alternate proximal signaling mechanism that might be responsible for nephrin tyrosine phosphorylation. Here we present data showing that integrin engagement at the basal aspect of cultured podocytes results in nephrin tyrosine phosphorylation. This is abrogated by incubating podocytes with an antibody that prevents integrin β1 ligation and activation in response to binding to extracellular matrix. Furthermore, nephrin tyrosine phosphorylation was observed in podocytes expressing a membrane-targeted nephrin construct that lacks the extracellular domain. We propose, integrin-activation based signaling might be responsible for nephrin phosphorylation rather than engagment of the nephrin extracellular domain by a ligand.

  19. Endoscopic band ligation for bleeding lesions in the small bowel

    Institute of Scientific and Technical Information of China (English)

    Takashi; Ikeya; Naoki; Ishii; Yuto; Shimamura; Kaoru; Nakano; Mai; Ego; Kenji; Nakamura; Koichi; Takagi; Katsuyuki; Fukuda; Yoshiyuki; Fujita

    2014-01-01

    AIM: To investigate the safety and efficacy of endo-scopic band ligation(EBL) for bleeding lesions in the small bowel.METHODS: This is a retrospective study evaluating EBL in six consecutive patients(three males, three fe-males, 46-86 years of age) treated between May 2009 and February 2014: duodenal vascular ectasia; 1, je-junal bleeding diverticulum; 1, ileal Dieulafoy’s lesion; 1 and ileal bleeding diverticula; 3. The success of the initial hemostasis was evaluated, and patients were observed for early rebleeding(within 30 d after EBL), and complications such as perforation and abscess for-mation. Follow-up endoscopies were performed in four patients.RESULTS: Initial hemostasis was successfully achieved with EBL in all six patients. Eversion was not sufficient in four diverticular lesions. Early rebleeding occurred three days after EBL in one ileal diverticulum, and arepeat endoscopy revealed dislodgement of the O-band and ulcer formation at the banded site. This rebleeding was managed conservatively. Late rebleeding occurred in this case(13 and 21 mo after initial EBL), and re-EBL was performed. Follow-up endoscopies revealed scar formation and the disappearance of vascular lesions at the banded site in the case with a duodenal bleeding lesion, and unresolved ileal diverticula in three cases. Surgery or transarterial embolization was not required without any complications during the median follow-up period of 45(range, 2-83) mo.CONCLUSION: EBL is a safe and effective endoscopic treatment for hemostasis of bleeding lesions in the small bowel.

  20. Permanent ligation of the left anterior descending coronary artery in mice: a model of post-myocardial infarction remodelling and heart failure.

    Science.gov (United States)

    Muthuramu, Ilayaraja; Lox, Marleen; Jacobs, Frank; De Geest, Bart

    2014-12-02

    Heart failure is a syndrome in which the heart fails to pump blood at a rate commensurate with cellular oxygen requirements at rest or during stress. It is characterized by fluid retention, shortness of breath, and fatigue, in particular on exertion. Heart failure is a growing public health problem, the leading cause of hospitalization, and a major cause of mortality. Ischemic heart disease is the main cause of heart failure. Ventricular remodelling refers to changes in structure, size, and shape of the left ventricle. This architectural remodelling of the left ventricle is induced by injury (e.g., myocardial infarction), by pressure overload (e.g., systemic arterial hypertension or aortic stenosis), or by volume overload. Since ventricular remodelling affects wall stress, it has a profound impact on cardiac function and on the development of heart failure. A model of permanent ligation of the left anterior descending coronary artery in mice is used to investigate ventricular remodelling and cardiac function post-myocardial infarction. This model is fundamentally different in terms of objectives and pathophysiological relevance compared to the model of transient ligation of the left anterior descending coronary artery. In this latter model of ischemia/reperfusion injury, the initial extent of the infarct may be modulated by factors that affect myocardial salvage following reperfusion. In contrast, the infarct area at 24 hr after permanent ligation of the left anterior descending coronary artery is fixed. Cardiac function in this model will be affected by 1) the process of infarct expansion, infarct healing, and scar formation; and 2) the concomitant development of left ventricular dilatation, cardiac hypertrophy, and ventricular remodelling. Besides the model of permanent ligation of the left anterior descending coronary artery, the technique of invasive hemodynamic measurements in mice is presented in detail.

  1. Preparation and characterization of nitrogen-doped TiO 2 nanoparticles by the laser pyrolysis of N 2O-containing gas mixtures

    Science.gov (United States)

    Alexandrescu, R.; Scarisoreanu, M.; Morjan, I.; Birjega, R.; Fleaca, C.; Luculescu, C.; Soare, I.; Cretu, O.; Negrila, C. C.; Lazarescu, N.; Ciupina, V.

    2009-03-01

    Nitrogen-doped TiO 2 nanoparticles have been prepared by the IR laser pyrolysis technique. A sensitized mixture of TiCl 4 (vapors) and N 2O was used as titanium and nitrogen precursors, respectively. The structural properties of the resultant N-doped nanoparticles such as the phase formation and the average particle size and distributions were investigated by X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy. The phase composition varied from almost pure anatase to mixtures of rutile and anatase. A decrease of the mean particle diameters from about 18 nm in case of the almost pure anatase sample to about 13 nm in case of the anatase-rutile mixture is observed. XPS analysis suggests and interstitial character of the doping process.

  2. Preparation and characterization of nitrogen-doped TiO{sub 2} nanoparticles by the laser pyrolysis of N{sub 2}O-containing gas mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Alexandrescu, R. [National Institute for Lasers, Plasma and Radiation Physics, POB MG-36, 077125 Bucharest (Romania)], E-mail: rodica.alexandrescu@inflpr.ro; Scarisoreanu, M.; Morjan, I.; Birjega, R.; Fleaca, C.; Luculescu, C.; Soare, I.; Cretu, O. [National Institute for Lasers, Plasma and Radiation Physics, POB MG-36, 077125 Bucharest (Romania); Negrila, C.C.; Lazarescu, N. [National Institute of Materials Physics, POB MG-7, 077125 Bucharest-Magurele (Romania); Ciupina, V. [Ovidius University of Constanta, Bd. Mamaia 124, Constanta (Romania)

    2009-03-01

    Nitrogen-doped TiO{sub 2} nanoparticles have been prepared by the IR laser pyrolysis technique. A sensitized mixture of TiCl{sub 4} (vapors) and N{sub 2}O was used as titanium and nitrogen precursors, respectively. The structural properties of the resultant N-doped nanoparticles such as the phase formation and the average particle size and distributions were investigated by X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy. The phase composition varied from almost pure anatase to mixtures of rutile and anatase. A decrease of the mean particle diameters from about 18 nm in case of the almost pure anatase sample to about 13 nm in case of the anatase-rutile mixture is observed. XPS analysis suggests and interstitial character of the doping process.

  3. Characterization of gate oxynitrides by means of time of flight secondary ion mass spectrometry and x-ray photoelectron spectroscopy. Quantification of nitrogen

    CERN Document Server

    Ferrari, S; Fanciulli, M

    2002-01-01

    We present a methodology for the quantitative estimation of nitrogen in ultrathin oxynitrides by means of time of flight secondary ion mass spectrometry (TOF-SIMS) and x-ray photoelectron spectroscopy (XPS). We consider an innovative approach to TOF-SIMS depth profiling, by elemental distribution of single species as sum of peaks containing such species. This approach is very efficient in overcoming matrix effect arising when quantifying elements were distributed in silicon and silicon oxide. We use XPS to calibrate TOF-SIMS and to obtain quantitative information on nitrogen distribution in oxynitride thin layers. In the method we propose we process TOF-SIMS and XPS data simultaneously to obtain a quantitative depth profile.

  4. A comparative study on time efficiency management of self ligating brackets with conventional ligating brackets on orthodontic subjects in North Karnataka

    Directory of Open Access Journals (Sweden)

    Smita B. Patil

    2014-01-01

    Full Text Available Background: Self-Ligating brackets were originally designed with the intention to reduce the time needed to change wires compared with the use of wire ligatures. However, the advent of elastomeric ligatures meant that this perceived advantage was diminished. Objective: To compare aligning efficiency, rate of retraction and torque expression of Self Ligating bracket (SLB system with Conventional Pre adjusted Edgewise bracket (CLB system. Materials and Methods: Twelve patients were selected and divided into two groups treated with self ligating brackets (SLB, n=6 and conventional ligating brackets (CLB, n=6. The brackets used were 0.22 slot McLaughlin Bennet Trevesi (MBT prescription. Aligning was evaluated with 0.14 Niti followed by 19X25 Heat Activated Ni Ti and then 19X25 stainless steel wires for retraction within 4 months. The rate of retraction was evaluated per month and torque loss after space closure was also estimated. Results: Alignment Efficiency shows significant changes with SLB compared to CLB and also save more than 30% of chair side time during wire adjustments while rate of en masse retraction in SLB shows statistically non significance as compared to CLB system. In case of upper incisor changes when compared between two groups showed less torque loss in SLB than CLB although which was statistically no significant but % difference show SLB have better improvement result than CLB.

  5. Nuclear Hyperfine and Quadrupole Tensor Characterization of the Nitrogen Hydrogen Bond Donors to the Semiquinone of the QB Site in Bacterial Reaction Centers: A Combined X- and S-Band 14,15N ESEEM and DFT Study

    Science.gov (United States)

    2015-01-01

    The secondary quinone anion radical QB– (SQB) in reaction centers of Rhodobacter sphaeroides interacts with Nδ of His-L190 and Np (peptide nitrogen) of Gly-L225 involved in hydrogen bonds to the QB carbonyls. In this work, S-band (∼3.6 GHz) ESEEM was used with the aim of obtaining a complete characterization of the nuclear quadrupole interaction (nqi) tensors for both nitrogens by approaching the cancelation condition between the isotropic hyperfine coupling and 14N Zeeman frequency at lower microwave frequencies than traditional X-band (9.5 GHz). By performing measurements at S-band, we found a dominating contribution of Nδ in the form of a zero-field nqi triplet at 0.55, 0.92, and 1.47 MHz, defining the quadrupole coupling constant K = e2qQ/4h = 0.4 MHz and associated asymmetry parameter η = 0.69. Estimates of the hyperfine interaction (hfi) tensors for Nδ and Np were obtained from simulations of 1D and 2D 14,15N X-band and three-pulse 14N S-band spectra with all nuclear tensors defined in the SQB g-tensor coordinate system. From simulations, we conclude that the contribution of Np to the S-band spectrum is suppressed by its strong nqi and weak isotropic hfi comparable to the level of hyperfine anisotropy, despite the near-cancelation condition for Np at S-band. The excellent agreement between our EPR simulations and DFT calculations of the nitrogen hfi and nqi tensors to SQB is promising for the future application of powder ESEEM to full tensor characterizations. PMID:24437652

  6. Nuclear hyperfine and quadrupole tensor characterization of the nitrogen hydrogen bond donors to the semiquinone of the QB site in bacterial reaction centers: a combined X- and S-band (14,15)N ESEEM and DFT study.

    Science.gov (United States)

    Taguchi, Alexander T; O'Malley, Patrick J; Wraight, Colin A; Dikanov, Sergei A

    2014-02-13

    The secondary quinone anion radical QB(-) (SQB) in reaction centers of Rhodobacter sphaeroides interacts with Nδ of His-L190 and Np (peptide nitrogen) of Gly-L225 involved in hydrogen bonds to the QB carbonyls. In this work, S-band (∼3.6 GHz) ESEEM was used with the aim of obtaining a complete characterization of the nuclear quadrupole interaction (nqi) tensors for both nitrogens by approaching the cancelation condition between the isotropic hyperfine coupling and (14)N Zeeman frequency at lower microwave frequencies than traditional X-band (9.5 GHz). By performing measurements at S-band, we found a dominating contribution of Nδ in the form of a zero-field nqi triplet at 0.55, 0.92, and 1.47 MHz, defining the quadrupole coupling constant K = e(2)qQ/4h = 0.4 MHz and associated asymmetry parameter η = 0.69. Estimates of the hyperfine interaction (hfi) tensors for Nδ and Np were obtained from simulations of 1D and 2D (14,15)N X-band and three-pulse (14)N S-band spectra with all nuclear tensors defined in the SQB g-tensor coordinate system. From simulations, we conclude that the contribution of Np to the S-band spectrum is suppressed by its strong nqi and weak isotropic hfi comparable to the level of hyperfine anisotropy, despite the near-cancelation condition for Np at S-band. The excellent agreement between our EPR simulations and DFT calculations of the nitrogen hfi and nqi tensors to SQB is promising for the future application of powder ESEEM to full tensor characterizations.

  7. Treatment of glioblastoma multiforme cells with temozolomide-BioShuttle ligated by the inverse Diels-Alder ligation chemistry

    Directory of Open Access Journals (Sweden)

    Klaus Braun

    2009-01-01

    Full Text Available Klaus Braun1, Manfred Wiessler1, Volker Ehemann2, Ruediger Pipkorn3, Herbert Spring4, Juergen Debus5, Bernd Didinger5, Mario Koch3, Gabriele Muller6, Waldemar Waldeck61German Cancer Research Center, Dept of Imaging and Radiooncology, Heidelberg, Germany; 2University of Heidelberg, Institute of Pathology, Heidelberg, Germany; 3German Cancer Research Center, Central Peptide Synthesis Unit, Heidelberg, Germany; 4German Cancer Research Center, Dept of Structural Analysis of Gene Structure and Function, Heidelberg, Germany; 5University of Heidelberg, Dept of Radiation Oncology, Heidelberg, Germany; 6German Cancer Research Center,Division of Biophysics of Macromolecules, Heidelberg, GermanyAbstract: Recurrent glioblastoma multiforme (GBM, insensitive against most therapeutic interventions, has low response and survival rates. Temozolomide (TMZ was approved for second-line therapy of recurrent anaplastic astrocytoma. However, TMZ therapy in GBM patients reveals properties such as reduced tolerability and inauspicious hemogram. The solution addressed here concerning GBM therapy consolidates and uses the potential of organic and peptide chemistry with molecular medicine. We enhanced the pharmacologic potency with simultaneous reduction of unwanted adverse reactions of the highly efficient chemotherapeutic TMZ. The TMZ connection to transporter molecules (TMZ-BioShuttle was investigated, resulting in a much higher pharmacological effect in glioma cell lines and also with reduced dose rate. From this result we can conclude that a suitable chemistry could realize the ligation of pharmacologically active, but sensitive and highly unstable pharmaceutical ingredients without functional deprivation. The TMZ-BioShuttle dramatically enhanced the potential of TMZ for the treatment of brain tumors and is an attractive drug for combination chemotherapy.Keywords: drug delivery, carrier molecules, facilitated transport, glioblastoma multiforme, temozolomide

  8. Multiple ligation of the proximal greater saphenous vein in the CHIVA treatment of primary varicose veins

    Directory of Open Access Journals (Sweden)

    Roberto Delfrate

    2014-06-01

    Full Text Available Saphenous femoral disconnection is the key point of most surgical techniques in the treatment of primary varicose vein surgery. The aim of this study is to compare and analyze different techniques for conservative saphenousfemoral ligation or disconnection. These techniques can be to perform mini invasive open surgery and are suitable for implementation of the conservative hemodynamic correction of venous insufficiency (CHIVA method. The aim was to present the follow-up by retrospective analysis of three different ligation-disconnection techniques of the proximal great saphenous vein (GSV according to the CHIVA method at the GSV end, i.e. between the very end of the GSV and the first arch tributary, according to the CHIVA method. The first thecnique consisted of a surgical division (crossotomy. The other two consisted of triple superposed ligation with No. 2 non-absorbable braided coated suture without division labeled TSFL (triple saphenous flush ligation and No. 0 polypropylenene ligation TPL (triple polypropylene ligation. The difference between TSFL and TPL was in the thickness and type of material of the thread, though both were non-absorbable. The follow up of 56 TPL procedures, 61 crossotomy procedures, and 82 TSFL procedures was analysed. The follow-up consisted of checking the sapheno-femoral junction occlusion with Duplex color ultra sound. The incidence rates of neovascularization (new vessels in the ligation or surgical disconnection site with saphenous-femoral reflux during the Valsalva maneuver were: 4.9% for the crossotomy group, 6.1% for the TSFL group and 37.5% for the TPL group. The data analysed show satisfactory results with both crossotomy and TSFL. Crossotomy has proven to be an effective technique for performing saphenous-femoral disconnection, but TSFL could also be a reliable, safe and low-cost varicose mini-invasive surgery in outpatients. TPL appeared to be less reliable.

  9. Effects of pulmonary veins ligation style for the patients' stress and cardiac on lung cancer

    Directory of Open Access Journals (Sweden)

    Yang SHENTU

    2008-10-01

    Full Text Available Background and objective It is needed to explore the effects of operation on stress statue, myocardial damage and arrhythmia to lung cancer. This study would compare the effects of two ligation styles of pulmonary vein on lung cancer patients' stress and cardiac postoperative. Methods 54 cases were divided into two groups randomly:the pulmonary vein trunk-ligation group (trunk group, 27 cases and the pulmonary vein branch-ligation group (branch group, 27 cases. The blood concentrations of hydrocortisone (HC, blood glucose (BG and cardial troponin-I (cTnI were determined at different time point. The surgical data, the quantum of pain and ECG also recorded. Results ① There were no significance difference of the operation time, blood loss during operation and drainage volume in first day after operation between two groups. ② There're no differences of the quantum of pain between two groups. ③ The HC of the two groups' ascend obviously on the end of operation and descend during postoperative. ④ The BG of the two groups' rise on the 1st day obviously, maintain high level on the 2nd day, descend on the 3rd day but still higher than that of preoperation.⑤ The BG and HC show a direct positive correlation postoperative. ⑥ The cTnIs of the trunk group ascend immediatelyafter operation, but there's no statistically significance between two groups. ⑦ The arrhythmia incidence is higher in the trunk group, but the arrhythmia incidences classified by the date after operation of the two groups' show no distinction. Conclusion ① The effects of two pulmonary vein ligation styles on postoperative stress show no significance differences.② The style of pulmonary vein trunk-ligation has a more obvious tendency to do harm to heart than that of branch-ligation. ③ The style of pulmonary vein branch-ligation may reduce the arrhythmia incidence after operation.

  10. Optimum level of inferior mesenteric artery ligation for the left-sided colorectal cancer

    Science.gov (United States)

    Guraya, Salman Y.

    2016-01-01

    Objectives: To compares the effectiveness and impact of high inferior mesenteric artery (IMA) versus low IMA ligation on 5-year survival, lymph node yield rates, and peri-operative morbidity and mortality. Methods: The databases of Educational Resources Information Centre (ERIC), the Web of Science, EBSCO and MEDLINE were searched using MeSH terms ‘colorectal cancer’, ‘inferior mesenteric artery’, ‘high ligation’, ‘low ligation’, ‘mesenteric lymph nodes’, ‘prognosis’, and ‘survival’. Only clinical studies were selected and review articles and meta-analysis were excluded. In cases of duplicate cohorts, only the latest article was included. Irrelevant articles and the articles on both right and left sided CRC were excluded. The finally selected studies were analysed for the defined end-point outcomes. Results: The published data has shown that high IMA ligation improves the yield of harvested lymph node that allows accurate tumor staging and a more reliable estimation of prognosis. High ligation was not found to be positively correlated with increased anastomotic leakage or impaired genito-urinary function. However, high ligation demands advanced surgical expertise and longer operating time. There was no significant difference in 5-year survival rates for both techniques. Some studies have reported fatal complications of high ligation such as proximal bowel necrosis. Conclusion: Although there is no consensus, this research signals the routine use of high ligation for left-sided CRC. However, the published fatal complications following high ligation and no significant difference in 5-year survival rates demand more studies to establishing a unified protocol. PMID:27381531

  11. Selective desulfurization of cysteine in the presence of Cys(Acm) in polypeptides obtained by native chemical ligation.

    Science.gov (United States)

    Pentelute, Brad L; Kent, Stephen B H

    2007-02-15

    Increased versatility for the synthesis of proteins and peptides by native chemical ligation requires the ability to ligate at positions other than Cys. Here, we report that Raney nickel can be used under standard conditions for the selective desulfurization of Cys in the presence of Cys(Acm). This simple and practical tactic enables the more common Xaa-Ala junctions to be used as ligation sites for the chemical synthesis of Cys-containing peptides and proteins. [reaction: see text].

  12. Effects of double ligation of Stensen's duct on the rabbit parotid gland.

    Science.gov (United States)

    Maria, O M; Maria, S M; Redman, R S; Maria, A M; Saad El-Din, T A; Soussa, E F; Tran, S D

    2014-04-01

    Salivary gland duct ligation is an alternative to gland excision for treating sialorrhea or reducing salivary gland size prior to tumor excision. Duct ligation also is used as an approach to study salivary gland aging, regeneration, radiotherapy, sialolithiasis and sialadenitis. Reports conflict about the contribution of each salivary cell population to gland size reduction after ductal ligation. Certain cell populations, especially acini, reportedly undergo atrophy, apoptosis and proliferation during reduction of gland size. Acini also have been reported to de-differentiate into ducts. These contradictory results have been attributed to different animal or salivary gland models, or to methods of ligation. We report here a bilateral double ligature technique for rabbit parotid glands with histologic observations at 1, 7, 14, 30, 60 days after ligation. A large battery of special stains and immunohistochemical procedures was employed to define the cell populations. Four stages with overlapping features were observed that led to progressive shutdown of gland activities: 1) marked atrophy of the acinar cells occurred by 14 days, 2) response to and removal of the secretory material trapped in the acinar and ductal lumens mainly between 30 and 60 days, 3) reduction in the number of parenchymal (mostly acinar) cells by apoptosis that occurred mainly between 14-30 days, and 4) maintenance of steady-state at 60 days with a low rate of fluid, protein, and glycoprotein secretion, which greatly decreased the number of leukocytes engaged in the removal of the luminal contents. The main post- ligation characteristics were dilation of ductal and acinar lumens, massive transient infiltration of mostly heterophils (rabbit polymorphonuclear leukocytes), acinar atrophy, and apoptosis of both acinar and ductal cells. Proliferation was uncommon except in the larger ducts. By 30 days, the distribution of myoepithelial cells had spread from exclusively investing the intercalated ducts

  13. Comparison and transfer testing of multiplex ligation detection methods for GM plants

    Directory of Open Access Journals (Sweden)

    Ujhelyi Gabriella

    2012-01-01

    Full Text Available Abstract Background With the increasing number of GMOs on the global market the maintenance of European GMO regulations is becoming more complex. For the analysis of a single food or feed sample it is necessary to assess the sample for the presence of many GMO-targets simultaneously at a sensitive level. Several methods have been published regarding DNA-based multidetection. Multiplex ligation detection methods have been described that use the same basic approach: i hybridisation and ligation of specific probes, ii amplification of the ligated probes and iii detection and identification of the amplified products. Despite they all have this same basis, the published ligation methods differ radically. The present study investigated with real-time PCR whether these different ligation methods have any influence on the performance of the probes. Sensitivity and the specificity of the padlock probes (PLPs with the ligation protocol with the best performance were also tested and the selected method was initially validated in a laboratory exchange study. Results Of the ligation protocols tested in this study, the best results were obtained with the PPLMD I and PPLMD II protocols and no consistent differences between these two protocols were observed. Both protocols are based on padlock probe ligation combined with microarray detection. Twenty PLPs were tested for specificity and the best probes were subjected to further evaluation. Up to 13 targets were detected specifically and simultaneously. During the interlaboratory exchange study similar results were achieved by the two participating institutes (NIB, Slovenia, and RIKILT, the Netherlands. Conclusions From the comparison of ligation protocols it can be concluded that two protocols perform equally well on the basis of the selected set of PLPs. Using the most ideal parameters the multiplicity of one of the methods was tested and 13 targets were successfully and specifically detected. In the

  14. Template-directed ligation of tethered mononucleotides by t4 DNA ligase for kinase ribozyme selection.

    Directory of Open Access Journals (Sweden)

    David G Nickens

    Full Text Available BACKGROUND: In vitro selection of kinase ribozymes for small molecule metabolites, such as free nucleosides, will require partition systems that discriminate active from inactive RNA species. While nucleic acid catalysis of phosphoryl transfer is well established for phosphorylation of 5' or 2' OH of oligonucleotide substrates, phosphorylation of diffusible small molecules has not been demonstrated. METHODOLOGY/PRINCIPAL FINDINGS: This study demonstrates the ability of T4 DNA ligase to capture RNA strands in which a tethered monodeoxynucleoside has acquired a 5' phosphate. The ligation reaction therefore mimics the partition step of a selection for nucleoside kinase (deoxyribozymes. Ligation with tethered substrates was considerably slower than with nicked, fully duplex DNA, even though the deoxynucleotides at the ligation junction were Watson-Crick base paired in the tethered substrate. Ligation increased markedly when the bridging template strand contained unpaired spacer nucleotides across from the flexible tether, according to the trends: A(2>A(1>A(3>A(4>A(0>A(6>A(8>A(10 and T(2>T(3>T(4>T(6 approximately T(1>T(8>T(10. Bridging T's generally gave higher yield of ligated product than bridging A's. ATP concentrations above 33 microM accumulated adenylated intermediate and decreased yields of the gap-sealed product, likely due to re-adenylation of dissociated enzyme. Under optimized conditions, T4 DNA ligase efficiently (>90% joined a correctly paired, or TratioG wobble-paired, substrate on the 3' side of the ligation junction while discriminating approximately 100-fold against most mispaired substrates. Tethered dC and dG gave the highest ligation rates and yields, followed by tethered deoxyinosine (dI and dT, with the slowest reactions for tethered dA. The same kinetic trends were observed in ligase-mediated capture in complex reaction mixtures with multiple substrates. The "universal" analog 5-nitroindole (dNI did not support ligation when

  15. Nucleosome linker proteins HMGB1 and histone H1 differentially enhance DNA ligation reactions.

    Science.gov (United States)

    Yamanaka, Shiho; Katayama, Eisaku; Yoshioka, Ken-ichi; Nagaki, Sumiko; Yoshida, Michiteru; Teraoka, Hirobumi

    2002-03-22

    We previously reported that HMGB1, which originally binds to chromatin in a manner competitive with linker histone H1 to modulate chromatin structure, enhances both intra-molecular and inter-molecular ligations. In this paper, we found that histone H1 differentially enhances ligation reaction of DNA double-strand breaks (DSB). Histone H1 stimulated exclusively inter-molecular ligation reaction of DSB with DNA ligase IIIbeta and IV, whereas HMGB1 enhanced mainly intra-molecular ligation reaction. Electron microscopy of direct DNA-protein interaction without chemical cross-linking visualized that HMGB1 bends and loops linear DNA to form compact DNA structure and that histone H1 is capable of assembling DNA in tandem arrangement with occasional branches. These results suggest that differences in the enhancement of DNA ligation reaction are due to those in alteration of DNA configuration induced by these two linker proteins. HMGB1 and histone H1 may function in non-homologous end-joining of DSB repair and V(D)J recombination in different manners.

  16. Characterization of edge profiles and fluctuations in discharges with type-II and nitrogen-mitigated edge localized modes in ASDEX Upgrade

    Energy Technology Data Exchange (ETDEWEB)

    Wolfrum, E; Bernert, M; Burckhart, A; Classen, I G J; Conway, G D; Eich, T; Fischer, R; Gude, A; Herrmann, A; Maraschek, M; McDermott, R; Puetterich, T; Wieland, B [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Garching (Germany); Boom, J E [FOM Institute for Plasmaphysics, Rijnhuizen, Association EURATOM-FOM, Nieuwegein (Netherlands); Luhmann, N C Jr [University of California at Davis, Davis, CA95616 (United States); Park, H K [POSTECH, Pohang, Gyeongbuk, 790-784 (Korea, Republic of); Vicente, J [Associacao EURATOM/IST, Instituto de Plasmas e Fosao Nuclear - Laboratorio Associado, IST, Lisbon (Portugal); Willensdorfer, M, E-mail: e.wolfrum@ipp.mpg.de [Institute of Applied Physics, Vienna University of Technology, Association EURATOM-OEAW, Vienna (Austria)

    2011-08-15

    Edge localized modes (ELMs) with high frequency and low power loss (type-II ELMs) occur in high triangularity, near double null configurations in ASDEX Upgrade with full tungsten plasma facing components. The transition from type-I to type-II ELMs is shown to occur above a collisionality threshold. For the first time the characteristic MHD fluctuations around 40 kHz have been localized. The fluctuations are observed in a wide region extending from the pedestal inward to normalized poloidal radius {rho}{sub pol} = 0.7. Their amplitudes on the low-field side of the plasma exhibit maxima above and below the mid-plane. The fluctuations move in the electron drift direction and lead to a reduced edge electron temperature gradient. The reduction in the edge pressure gradient is connected with these MHD fluctuations, which affect the electron temperature but not the electron density profiles. A comparison with nitrogen-mitigated type-I ELMs in the same plasma shape shows that core profiles are also affected. The electron temperature profile is self-similar for type-I and nitrogen-mitigated type-I ELMs but is not self-similar in the case of type-II ELMs.

  17. The Diels-Alder-reaction with inverse-electron-demand, a very efficient versatile click-reaction concept for proper ligation of variable molecular partners.

    Science.gov (United States)

    Wiessler, Manfred; Waldeck, Waldemar; Kliem, Christian; Pipkorn, Ruediger; Braun, Klaus

    2009-12-05

    The ligation of active pharmaceutical ingredients (API) for working with image processing systems in diagnostics (MRT) attracts increasing notice and scientific interest. The Diels-Alder ligation Reaction with inverse electron demand (DAR(inv)) turns out to be an appropriate candidate. The DAR(inv) is characterized by a specific distribution of electrons of the diene and the corresponding dienophile counterpart. Whereas the reactants in the classical Diels-Alder Reaction feature electron-rich diene and electron-poor dienophile compounds, the DAR(inv) exhibits exactly the opposite distribution of electrons. Substituents with pushing electrones increase and, with pulling electrons reduce the electron density of the dienes as used in the DAR(inv).We report here that the DAR(inv) is an efficient route for coupling of multifunctional molecules like active peptides, re-formulated drugs or small molecules like the alkyalting agent temozolomide (TMZ). This is an example of our contribution to the "Click chemistry" technology. In this case TMZ is ligated by DAR(inv) as a cargo to transporter molecules facilitating the passage across the cell membranes into cells and subsequently into subcellular components like the cell nucleus by using address molecules. With such constructs we achieved high local concentrations at the desired target site of pharmacological action. The DAR(inv) ligation was carried out using the combination of several technologies, namely: the organic chemistry and the solid phase peptide synthesis which can produce 'tailored' solutions for questions not solely restricted to the medical diagnostics or therapy, but also result in functionalizations of various surfaces qualified amongst others also for array development.We like to acquaint you with the DAR(inv) and we like to exemplify that all ligation products were generated after a rapid and complete reaction in organic solutions at room temperature, in high purity, but also, hurdles and difficulties on

  18. The Diels-Alder-Reaction with inverse-Electron-Demand, a very efficient versatile Click-Reaction Concept for proper Ligation of variable molecular Partners

    Directory of Open Access Journals (Sweden)

    Manfred Wiessler, Waldemar Waldeck, Christian Kliem, Ruediger Pipkorn, Klaus Braun

    2010-01-01

    Full Text Available The ligation of active pharmaceutical ingredients (API for working with image processing systems in diagnostics (MRT attracts increasing notice and scientific interest. The Diels-Alder ligation Reaction with inverse electron demand (DARinv turns out to be an appropriate candidate. The DARinv is characterized by a specific distribution of electrons of the diene and the corresponding dienophile counterpart. Whereas the reactants in the classical Diels-Alder Reaction feature electron-rich diene and electron-poor dienophile compounds, the DARinv exhibits exactly the opposite distribution of electrons. Substituents with pushing electrones increase and, with pulling electrons reduce the electron density of the dienes as used in the DARinv. We report here that the DARinv is an efficient route for coupling of multifunctional molecules like active peptides, re-formulated drugs or small molecules like the alkyalting agent temozolomide (TMZ. This is an example of our contribution to the "Click chemistry" technology. In this case TMZ is ligated by DARinv as a cargo to transporter molecules facilitating the passage across the cell membranes into cells and subsequently into subcellular components like the cell nucleus by using address molecules. With such constructs we achieved high local concentrations at the desired target site of pharmacological action. The DARinv ligation was carried out using the combination of several technologies, namely: the organic chemistry and the solid phase peptide synthesis which can produce 'tailored' solutions for questions not solely restricted to the medical diagnostics or therapy, but also result in functionalizations of various surfaces qualified amongst others also for array development. We like to acquaint you with the DARinv and we like to exemplify that all ligation products were generated after a rapid and complete reaction in organic solutions at room temperature, in high purity, but also, hurdles and difficulties on

  19. Isolation and Characterization of a Lycopene ε-Cyclase Gene of Chlorella (Chromochloris zofingiensis. Regulation of the Carotenogenic Pathway by Nitrogen and Light

    Directory of Open Access Journals (Sweden)

    Maria Angeles Vargas

    2012-09-01

    Full Text Available The isolation and characterization of the lycopene ε-cyclase gene from the green microalga Chlorella (Chromochloris zofingiensis (Czlcy-e was performed. This gene is involved in the formation of the carotenoids α-carotene and lutein. Czlcy-e gene encoded a polypeptide of 654 amino acids. A single copy of Czlcy-e was found in C. zofingiensis. Functional analysis by heterologous complementation in Escherichia coli showed the ability of this protein to convert lycopene to δ-carotene. In addition, the regulation of the carotenogenic pathway by light and nitrogen was also studied in C. zofingiensis. High irradiance stress did not increase mRNA levels of neither lycopene β-cyclase gene (lcy-b nor lycopene ε-cyclase gene (lcy-e as compared with low irradiance conditions, whereas the transcript levels of psy, pds, chyB and bkt genes were enhanced, nevertheless triggering the synthesis of the secondary carotenoids astaxanthin, canthaxanthin and zeaxanthin and decreasing the levels of the primary carotenoids α-carotene, lutein, violaxanthin and β-carotene. Nitrogen starvation per se enhanced mRNA levels of all genes considered, except lcy-e and pds, but did not trigger the synthesis of astaxanthin, canthaxanthin nor zeaxanthin. The combined effect of both high light and nitrogen starvation stresses enhanced significantly the accumulation of these carotenoids as well as the transcript levels of bkt gene, as compared with the effect of only high irradiance stress.

  20. Determination of the antiulcer properties of sodium cromoglycate in pylorus-ligated albino rats

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    Srivastava Vivek

    2010-01-01

    Full Text Available Objectives : To study the ulcer protective property of sodium cromoglycate in pylorus-ligated rats and the biochemical role in ulcer protection by various biochemical tests. Materials and Methods : The ulcer protective effect of sodium cromoglycate was studied using a Pyloric Ligation Model using Wistar albino rats. The antiulcer effect of sodium cromoglycate 40 mg/kg b.w., i.p., was compared with the reference drug ranitidine 27 mg/kg b.w., i.p. The ulcer index was calculated and other biochemical parameters like free acidity, total acidity, pH, mucin, pepsin and volume of gastric juice were determined. Results : Pylorus ligation showed a significant (P < 0.01 reduction in gastric volume, free acidity, total acidity and ulcer index as compared to the control. Conclusion : Sodium cromoglycate has activity equipotent to ranitidine.

  1. Ligation versus bipolar diathermy for hemostasis in tonsillectomy: a comparative study.

    Science.gov (United States)

    Sharma, Karan; Kumar, Devinder

    2011-01-01

    Tonsillectomy despite being less performed nowadays still is a very common surgery performed by ENT surgeons. The use of various modalities like bipolar diathermy, laser, cryosurgery, radiofrequency and ionic coblation for hemostasis in tonsillectomy remains controversial so far. A thorough scan of literature comparing the ligation with diathermy has been presented. In this prospective study, we analysed 50 patients undergoing tonsillectomy by dissection method. Right sided tonsillectomies act as study group (bipolar diathermy used) and left sided tonsillectomies as the control group (ligation for hemostasis used). The aim of our study is to compare the amount of blood loss, number of ligatures applied, average time taken and incidence of postoperative haemorrhage following the use of ligation and bipolar diathermy. The study found that diathermy hemostatic technique is associated with a quicker procedure, less intraoperative blood loss, comparable postoperative pain.

  2. Influence of polyethylene glycol on the ligation reaction with calf thymus DNA ligases I and II.

    Science.gov (United States)

    Teraoka, H; Tsukada, K

    1987-01-01

    High concentrations of the nonspecific macromolecule polyethylene glycol 6000 (PEG 6000) enabled DNA ligases I and II from calf thymus to catalyze intermolecular blunt-end ligation of duplex DNA. Intermolecular cohesive-end ligation with these enzymes was markedly stimulated in the presence of 10-16% (w/v) PEG 6000. The effect of PEG 6000 (4-16%) on the sealing of single-stranded breaks in duplex DNA with DNA ligases I and II was not appreciably stimulatory but rather inhibitory. PEG 6000 (15%) enhanced more twofold the rate of DNA ligase II-AMP complex formation, but moderately suppressed the rate of formation of DNA ligase 1-AMP complex. Polyamines and KCl inhibited blunt-end and cohesive-end ligations with DNA ligases I and II in the presence of PEG 6000.

  3. GASTROPROTECTIVE EFFECTS OF FRUITS OF TRIBULUS TERRESTRIS L. IN PYLORUS-LIGATED WISTAR RAT MODEL

    Directory of Open Access Journals (Sweden)

    Sanjay Jain*, Rakesh Barik, Nidhi Yadav and Shivpal Singh

    2013-01-01

    Full Text Available Tribulus terrestris L. (TT; Zygophyllaceae is employed in the folk medicine against sexual impotence, oedemas, abdominal distention and cardiovascular diseases. Gastroprotective (i.e. antiulcer and anti-secretory potential of methanolic extract of TT fruits was evaluated in pylorus-ligated rat model of Wistar rat. The methanolic extract of TT was tested orally at the doses of 150, 300 & 600 mg/kg, on gastric ulcerations experimentally induced by pylorus ligation. Preliminary phytochemical screening of the methanol extract of TT showed the presence of alkaloids, carbohydrates, cardiac glycosides, flavonoids, saponins, tannins and proteins. The methanolic extract at the doses of 300 & 600 mg/kg produced more significant inhibition when gastric ulcerations were induced by pylorus ligation respectively. The methanol extract of the fruits of Tribulus terrestris L. possess gastroprotective i.e. antiulcer and anti-secretory effect.

  4. Structural characterization of the protein cce_0567 from Cyanothece 51142, a metalloprotein associated with nitrogen fixation in the DUF683 family

    Energy Technology Data Exchange (ETDEWEB)

    Buchko, Garry W.; Robinson, Howard; Addlagatta, Anthony

    2009-03-11

    The genome of many cyanobacacteria contain the sequence for a small protein (<100 amino acids) with a commom "domain of unknown function" grouped into the DUF683 protein family. While the biological function of DUF683 is still not known, their genomic location within nitrogen fixation clusters suggests that DUF683 proteins may play a role in the process. The diurnal cyanobacterium Cyanothece sp. PCC 51142 contains a gene for a protein that fall into the DUF683 family, cce_0567 (78 aa, 9.0 kDa). In an effort to elucidate the biochemical role DUF683 proteins may play in nitrogen fixation, we have determined the first crystal structure for a protein in this family, cce_0567, to 1.84 Å resolution. Cce_0567 crystallized in space group P21 with two protein molecules and one Ni2+ cation per asymmetric unit. The protein is composed of two α-helices from residues P11 to G41 (α1) and L49-E74 (α2) with the second α-helix containing a short 310-helix (Y46 - N48). A four-residue linker (L42 - D45) between the helices allows them to form an anti-parallel bundle that cross over each other towards their termini. In solution it is likely that two molecules of cce_0567 form a rod-like dimer by the stacking interactions of ~1/2 of the protein. Histidine-36 is highly conserved in all known DUF683 proteins and the N2 nitrogen of the H36 side chain of each molecule in the dimer coordinate with Ni2+ in the crystal structure. The divalent cation Ni2+ was titrated into 15N-labelled cce_0567 and chemical shift perturbations were observed only in the 1H-15N HSQC spectra for residues at, or near, the site of Ni2+ binding observed in the crystal structure. There was no evidence for an increase in the size of cce_0567 upon binding Ni2+, even in large molar excess of Ni2+, indicating that a metal was not required for dimer formation. Circular dichroism spectroscopy indicated that cce_0567 was extremely robust, with a melting temperature of ~62ºC that was reversible.

  5. Structural characterization of the protein cce_0567 from Cyanothece 51142, a metalloprotein associated with nitrogen fixation in the DUF683 family.

    Science.gov (United States)

    Buchko, Garry W; Robinson, Howard; Addlagatta, Anthony

    2009-04-01

    The genomes of many cyanobacteria contain the sequence for a small protein with a common "Domain of Unknown Function" grouped into the DUF683 protein family. While the biological function of DUF683 is still not known, their genomic location within nitrogen fixation clusters suggests that DUF683 proteins may play a role in the process. The diurnal cyanobacterium Cyanothece sp. PCC 51142 contains a gene for a protein that falls into the DUF683 family, cce_0567 (78 aa, 9.0 kDa). In an effort to elucidate the biochemical role DUF683 proteins may play in nitrogen fixation, we have determined the first crystal structure for a protein in this family, cce_0567, to 1.84 A resolution. Cce_0567 crystallized in space group P2(1) with two protein molecules and one Ni(2+) cation per asymmetric unit. The protein is composed of two alpha-helices, residues P11 to G41 (alpha1) and L49-E74 (alpha2), with the second alpha-helix containing a short 3(10)-helix (Y46-N48). A four-residue linker (L42-D45) between the helices allows them to form an anti-parallel bundle and cross over each other towards their termini. In solution it is likely that two molecules of cce_0567 form a rod-like dimer by the stacking interactions of approximately 1/2 of the protein. Histidine-36 is highly conserved in all known DUF683 proteins and the N2 nitrogen of the H36 side chain of each molecule in the dimer is coordinated with Ni(2+) in the crystal structure. The divalent cation Ni(2+) was titrated into (15)N-labeled cce_0567 and chemical shift perturbations were observed only in the (1)H-(15)N HSQC spectra for residues at, or near, the site of Ni(2+) binding observed in the crystal structure. There was no evidence for an increase in the size of cce_0567 upon binding Ni(2+), even in large molar excess of Ni(2+), indicating that a metal was not required for dimer formation. Circular dichroism spectroscopy indicated that cce_0567 was extremely robust, with a melting temperature of approximately 62 degrees C

  6. Structural Characterization of the Protein cce_0567 from Cyanothece 51142, a Metalloprotein Associated with Nitrogen Fixation in the DUF683 Family

    Energy Technology Data Exchange (ETDEWEB)

    Buchko, G.; Robinson, H; Addlagatta, A

    2009-01-01

    The genomes of many cyanobacteria contain the sequence for a small protein with a common 'Domain of Unknown Function' grouped into the DUF683 protein family. While the biological function of DUF683 is still not known, their genomic location within nitrogen fixation clusters suggests that DUF683 proteins may play a role in the process. The diurnal cyanobacterium Cyanothece sp. PCC 51142 contains a gene for a protein that falls into the DUF683 family, cce 0567 (78 aa, 9.0 kDa). In an effort to elucidate the biochemical role DUF683 proteins may play in nitrogen fixation, we have determined the first crystal structure for a protein in this family, cce 0567, to 1.84 A resolution. Cce 0567 crystallized in space group P2(1) with two protein molecules and one Ni(2+) cation per asymmetric unit. The protein is composed of two alpha-helices, residues P11 to G41 (alpha1) and L49-E74 (alpha2), with the second alpha-helix containing a short 3(10)-helix (Y46-N48). A four-residue linker (L42-D45) between the helices allows them to form an anti-parallel bundle and cross over each other towards their termini. In solution it is likely that two molecules of cce 0567 form a rod-like dimer by the stacking interactions of approximately 1/2 of the protein. Histidine-36 is highly conserved in all known DUF683 proteins and the N2 nitrogen of the H36 side chain of each molecule in the dimer is coordinated with Ni(2+) in the crystal structure. The divalent cation Ni(2+) was titrated into (15)N-labeled cce 0567 and chemical shift perturbations were observed only in the (1)H-(15)N HSQC spectra for residues at, or near, the site of Ni(2+) binding observed in the crystal structure. There was no evidence for an increase in the size of cce 0567 upon binding Ni(2+), even in large molar excess of Ni(2+), indicating that a metal was not required for dimer formation. Circular dichroism spectroscopy indicated that cce 0567 was extremely robust, with a melting temperature of approximately 62

  7. Frictional resistance of self-ligating versus conventional brackets in different bracket-archwire-angle combinations

    Directory of Open Access Journals (Sweden)

    Maria Regina Guerra MONTEIRO

    2014-06-01

    Full Text Available Objective: To compare the influence of archwire material (NiTi, beta-Ti and stainless steel and brackets design (self-ligating and conventional on the frictional force resistance. Material and Methods: Two types of brackets (self-ligating brackets - Smartclip, 3M/Unitek - and conventional brackets - Gemini, 3M/Unitek with three (0, 5, and 10 degrees slot angulation attached with elastomeric ligatures (TP Orthodontics were tested. All brackets were tested with archwire 0.019"x0.025" nickel-titanium, beta-titanium, and stainless steel (Unitek/3M. The mechanical testing was performed with a universal testing machine eMIC DL 10000 (eMIC Co, Brazil. The wires were pulled from the bracket slots at a cross-head speed of 3 mm/min until 2 mm displacement. Results: Self-ligating brackets produced significantly lower friction values compared with those of conventional brackets. Frictional force resistance values were directly proportional to the increase in the bracket/ wire angulation. With regard to conventional brackets, stainless steel wires had the lowest friction force values, followed by nickel-titanium and beta-titanium ones. With regard to self-ligating brackets, the nickel-titanium wires had the lowest friction values, significantly lower than those of other materials. Conclusion: even at different angulations, the self-ligating brackets showed significantly lower friction force values than the conventional brackets. Combined with nickel-titanium wires, the self-ligating brackets exhibit much lower friction, possibly due to the contact between nickel-titanium clips and wires of the same material.

  8. The effect of ligation of the distal vein in snuff-box arteriovenous fistula

    Directory of Open Access Journals (Sweden)

    Beigi Ali

    2009-01-01

    Full Text Available Arterio-venous fistula (AVF in the snuff-box region is one of the current techniques used for creating a vascular access in patients undergoing dialysis. The aim of this study is to find out whether ligating the distal vein in AVF in the snuff-box will bring about any change in the efficiency and complications of the fistula. Sixty patients (30 males, 30 females suffering from chronic renal failure, who had been admitted for creating an AVF, were randomly divided into two groups after having filled out consent forms. After the AVF was made, the distal vein was ligated in the first group, but not in the second group. The patients were discharged after being given the necessary advice on how to take care of their fistula. They were examined on post-surgical days 1, 30 and 90. Early efficiency in the ligated and non-ligated groups was 100% and 96.7% respectively while late efficiency in the two groups was 90% and 83.4%, respectively (P > 0.05. The most common complication in both groups was thrombosis (11.7%. Venous hypertension and edema were observed in two patients (both from the non-ligated group and infection of the surgical site was observed in only one patient. Our study suggests that, considering the high efficiency level and low complication rate, AVF at the snuff-box region constitutes one of the best possible vascular accesses for patients undergoing hemodialysis. Ligation of the distal vein prevents the development of venous hypertension in the fistula.

  9. Synthesis of nitrogen-doped ZnO by sol-gel method: characterization and its application on visible photocatalytic degradation of 2,4-D and picloram herbicides.

    Science.gov (United States)

    Macías-Sánchez, J J; Hinojosa-Reyes, L; Caballero-Quintero, A; de la Cruz, W; Ruiz-Ruiz, E; Hernández-Ramírez, A; Guzmán-Mar, J L

    2015-03-01

    In this work, nitrogen-doped ZnO material was synthesized by the sol-gel method using zinc acetate as the precursor and urea as the nitrogen source (15, 20, 25 and 30% wt.). For comparative purposes, bare ZnO was also prepared. The influence of N doping on structural, morphological, optical and photocatalytic properties was investigated. The synthesized catalysts were characterized by XRD, SEM-EDS, diffuse reflectance UV-Vis spectroscopy, BET and XPS analysis. The photocatalytic activity of N-doped ZnO catalysts was evaluated during the degradation of a mixture of herbicides (2,4-D and picloram) under visible radiation ≥400 nm. The photo-absorption wavelength range of the N-doped ZnO samples was shifted to longer wavelength compared to those of the unmodified ZnO. Among different amounts of dopant agent, the 30% N-doped ZnO material showed higher visible-light activity compared with pure ZnO. Several degradation by-products were identified by using HPLC and ESI-MS/MS. The enhancement of visible photocatalytic activity of the N-doped ZnO semiconductor could be mainly due to their capability in reducing the electron-hole pair recombination.

  10. Chronic heart failure model with sequential ligation of the homonymous artery and its diagonal branch in the sheep.

    Science.gov (United States)

    Kim, W G; Park, J J; Oh, S I

    2001-01-01

    We report a reliable chronic heart failure model in sheep using sequential ligation of the homonymous artery and its diagonal branch. After a left anterior thoracotomy in Corridale sheep, the homonymous artery was ligated at a point approximately 40% of the distance from the apex to the base of the heart, and after 1 hour, the diagonal vessel was ligated at a point at the same level. Hemodynamic measurements were done preligation, 30 minutes after the homonymous artery ligation, and 1 hour after diagonal branch ligation. The electrocardiograms were obtained as needed, and cardiac function was also evaluated with ultrasonography. After a predetermined interval (2 months for five animals and 3 months for two animals), the animals were reevaluated in the same way as before, and were killed for postmortem examination of their hearts. All seven animals survived the experimental procedures. Statistically significant decreases in systemic arterial blood pressure and cardiac output and increases in pulmonary artery capillary wedge pressure were observed 1 hour after sequential ligation of the homonymous artery and its diagonal branch. Untrasonographic analyses demonstrated variable degrees of anteroseptal dyskinesia and akinesia in all animals. The data from animals at 2 months after coronary artery ligation showed significant increases in central venous pressure, pulmonary artery pressure, and pulmonary artery capillary wedge pressure. Left ventricular enddiastolic dimension and left ventricular end-systolic dimension on ultrasonographic studies were also increased. Electrocardiography showed severe ST elevation immediately after the ligation and pathologic Q waves were found at 2 months after ligation. The thin walled infarcted areas with chamber enlargement were clearly seen in the hearts removed at 2 and 3 months after ligation. In conclusion, we could achieve a reliable ovine model of chronic heart failure using a simple concept of sequential ligation of the

  11. ROLE OF INTERNAL ILIAC ARTERY LIGATION IN CONTROL OF PELVIC HEMORRHAGE.

    Directory of Open Access Journals (Sweden)

    Vidyadhar Bangal

    2009-06-01

    Full Text Available Hemorrhage in pregnancy is the leading cause of maternal mortality in developing countries. Internaliliac artery ligation is one of the life saving procedures in intractable pelvic hemorrhage. Althougheffective, the procedure is not commonly performed by obstetricians and gynecologists. Present paper aims at sharing author’s experience about usefulness of this surgical procedure in arrest of pelvic hemorrhage and to remove the inhibition among practicing gynecologists regarding this procedure.Fifty four cases of pelvic hemorrhage were managed by internal iliac artery ligation over 15 year period at tertiary care center. Hemorrhage could be arrested in all cases.

  12. Coronary ligation reduces maximum sustained swimming speed in Chinook salmon, Oncorhynchus tshawytscha

    DEFF Research Database (Denmark)

    Farrell, A P; Steffensen, J F

    1987-01-01

    The maximum aerobic swimming speed of Chinook salmon (Oncorhynchus tshawytscha) was measured before and after ligation of the coronary artery. Coronary artery ligation prevented blood flow to the compact layer of the ventricular myocardium, which represents 30% of the ventricular mass, and produced...... a statistically significant 35.5% reduction in maximum swimming speed. We conclude that the coronary circulation is important for maximum aerobic swimming and implicit in this conclusion is that maximum cardiac performance is probably necessary for maximum aerobic swimming performance....

  13. Bis-ligated Ti and Zr complexes of chelating N-heterocyclic carbenes

    KAUST Repository

    El-Batta, Amer

    2011-07-01

    In this communication we report the synthesis of novel titanium and zirconium complexes ligated by bidentate "salicylaldimine-like" N-heterocyclic carbenes (NHC). Double addition of the NHC chelate to either TiCl4(thf)2 or ZrCl4 forms bis-ligated organometallic fragments with a distorted octahedral geometry. These complexes are rare examples of group IV transition-metal NHC adducts. Preliminary catalytic tests demonstrate that in the presence of methylaluminoxane (MAO) these complexes are useful initiators for the polymerization of ethylene and the copolymerization of ethylene with norbornene and 1-octene. © 2011 Elsevier B.V. All rights reserved.

  14. Impairment of the organization of locomotor and exploratory behaviors in bile duct-ligated rats

    DEFF Research Database (Denmark)

    Leke, Renata; de Oliveira, Diogo L; Mussulini, Ben Hur M.;

    2012-01-01

    female Wistar rats underwent common bile duct ligation (BDL rats) or the manipulation of common bile duct without ligation (control rats). Six weeks after surgery, control and BDL rats underwent open-field, plus-maze and foot-fault behavioral tasks. The BDL rats developed chronic liver failure...... from the control rats for the elevated plus-maze and foot-fault tasks. Therefore, the BDL rats demonstrated disturbed spontaneous locomotor and exploratory activities as a consequence of altered spatio-temporal organization of behavior....

  15. INTERNAL ILIAC ARTERY LIGATION AFTER CAESERIAN HYSTERECTOMY IN POST - PARTUM HAEMORRHAGE LIFE SAVING PROCEDURE

    Directory of Open Access Journals (Sweden)

    Vijayalakshmi

    2015-07-01

    Full Text Available Internal iliac artery (Hypogastric supplies the pelvic viscera. Bilateral ligation of the internal iliac arteries is a safe, rapid and very effective method of controlling bleeding from genital tract. It is also helpful in massive broad ligament hematoma, in torn vessels retracted within th e broad ligament, and even in postoperative hemorrhage after abdominal or vaginal hysterectomy where there are no definitive bleeding points detectable. Bilateral ligation of internal iliac arteries is also helpful in life threatening hemorrhagic condition s like postpartum hemorrhage, placenta previa, cervical and vaginal tear, cervical pregnancy and uterine rupture etc.

  16. An equation for calculating the volumetric ratios required in a ligation reaction.

    Science.gov (United States)

    Cranenburgh, R M

    2004-08-01

    The ligation of two DNA fragments to create a new plasmid DNA molecule is a key reaction in molecular biology. Where the fragment lengths and concentrations are known, existing equations allow the desired relative molar ratio to be calculated, but this must then be related to the required volumes. Further calculations are then necessary if the maximum available volume is to consist of DNA solutions. The equation presented here allows the simple calculation of volumes of DNA solutions required to obtain a desired molar insert-to-vector ratio, and these can comprise all of the available volume in a ligation if required, thus maximising the yield of the recombinant plasmid.

  17. Enzymatic Ligation Creates Discrete Multi-Nanoparticle Building Blocks for Self-Assembly

    Energy Technology Data Exchange (ETDEWEB)

    Claridge, Shelley A.; Mastroianni, Alexander J.; Au, Yeung B.; Liang, Huiyang W.; Micheel, Christine M.; Frechet, Jean M.J.; Alivisatos, A. Paul

    2008-05-27

    Enzymatic ligation of discrete nanoparticle?DNA conjugates creates nanoparticle dimer and trimer structures in which the nanoparticles are linked by single-stranded DNA, rather than double-stranded DNA as in previous experiments. Ligation is verified by agarose gel and small-angle X-ray scattering. This capability is utilized in two ways: first to create a new class of multiparticle building blocks for nanoscale self-assembly; second to develop a system which can amplify a population of discrete nanoparticle assemblies.

  18. Enzyme Treatment-Free and Ligation-Independent Cloning Using Caged Primers in Polymerase Chain Reactions

    Directory of Open Access Journals (Sweden)

    Akinori Kuzuya

    2011-12-01

    Full Text Available A new simple scheme for constructing recombinant vectors that does not require any restriction enzyme, ligase, or any other special enzyme treatment has been developed. By using caged primers in PCR, unnatural sticky-ends of any sequence, which are sufficiently long for ligation-independent cloning (LIC, are directly prepared on the product after a brief UVA irradiation. Target genes and vectors amplified by this light-assisted cohesive-ending (LACE PCR join together in the desired arrangement in a simple mixture of them, tightly enough to be repaired and ligated in competent cells.

  19. Preparation, Characterization and Basic Catalytic Properties of Nitrogen-incorporated FAU Zeolites%含氮FAU分子筛的制备、表征及碱催化反应性能

    Institute of Scientific and Technical Information of China (English)

    王涛; 武光军; 李兰冬; 关乃佳

    2011-01-01

    Dehydration-nitridation method was employed to prepare nitrogen-incorporated HY zeolites. High crystallinity and specific surface area of parent HY were well preserved in nitrogen-incorporated HY zeolites.The base strength of HY framework was enhanced due to the replacement of oxygen by nitrogen with lower electronegativity. The acidity and basicity of nitrogen-incorporated HY zeolite were characterized by IR spectra using NH3 and CO2 as probe molecules and temperature-programmed desorption of CO2. The results show that the amounts of L-acid sites decrease while the amount of B-acid sites and base sites increase after nitridation.Moreover, new base sites with moderate strength are created after nitridation. Compared to parent HY zeolite,the nitridized sample exhibits improved basic catalytic performance in Knoevenagel condensation reaction.%利用脱水氮化法制备了含氮HY分子筛,氮化后分子筛的结晶度和比表面积均得到较好保持.由于氮原子的电负性低于氧原子,因此氮原子取代氧原子进入HY分子筛的骨架后,使其Lewis碱性得到增强.利用氨气吸附红外光谱、二氧化碳吸附红外光谱及二氧化碳程序升温脱附等方法对氮化前后的分子筛进行表征.结果表明,氮化后HY分子筛的L酸中心数量有所降低,B酸中心数量有所增加,同时生成新的碱性中心.由于新碱性中心的引入,含氮HY分子筛在Knoevenagel缩合碱性探针反应中表现出良好的活性.

  20. Associated Liver Partition and Portal Vein Ligation (ALPPS) vs Selective Portal Vein Ligation (PVL) for Staged Hepatectomy in a Rat Model. Similar Regenerative Response?

    Science.gov (United States)

    García-Pérez, Rocío; Revilla-Nuin, Beatriz; Martínez, Carlos M; Bernabé-García, Angel; Baroja Mazo, Alberto; Parrilla Paricio, Pascual

    2015-01-01

    Associated liver partition and portal vein ligation for staged hepatectomy (ALPPS) is a two-stage hepatectomy technique which can be associated with a hypertrophic stimulus on the future liver remnant (FLR) stronger than other techniques--such as portal vein ligation (PVL). However, the reason of such hypertrophy is still unclear, but it is suggested that liver transection combined with portal vein ligation (ALPPS) during the first stage of this technique may play a key role. The aim of this study is to compare the hypertrophic stimulus on the FLR and the clinical changes associated with both ALPPS and PVL in a rat surgical model. For this purpose, three groups of SD rats were used, namely ALPPS (n = 30), PVL (n = 30) and sham-treated (n = 30). The second stage of ALPPS (hepatectomy of the atrophic lobes), was performed at day 8. Blood and FLR samples were collected at 1, 24, 48 hours, 8 days and 12 weeks after the surgeries. ALPPS provoked a greater degree of hypertrophy of the FLR than the PVL at 48 hours and 8 days (pstimulus at 12 weeks, with a higher expression of HGF and TGF-β (presponse seems to be leaded by a complex interaction between pro-mitogenic (IL-6, HGF, TNF-α) and antiproliferative (IL1-β and TGF-β) cytokines.

  1. Mean age distribution of inorganic soil-nitrogen

    Science.gov (United States)

    Woo, Dong K.; Kumar, Praveen

    2016-07-01

    Excess reactive nitrogen in soils of intensively managed landscapes causes adverse environmental impact, and continues to remain a global concern. Many novel strategies have been developed to provide better management practices and, yet, the problem remains unresolved. The objective of this study is to develop a model to characterize the "age" of inorganic soil-nitrogen (nitrate, and ammonia/ammonium). We use the general theory of age, which provides an assessment of the time elapsed since inorganic nitrogen has been introduced into the soil system. We analyze a corn-corn-soybean rotation, common in the Midwest United States, as an example application. We observe two counter-intuitive results: (1) the mean nitrogen age in the topsoil layer is relatively high; and (2) mean nitrogen age is lower under soybean cultivation compared to corn although no fertilizer is applied for soybean cultivation. The first result can be explained by cation-exchange of ammonium that retards the leaching of nitrogen, resulting in an increase in the mean nitrogen age near the soil surface. The second result arises because the soybean utilizes the nitrogen fertilizer left from the previous year, thereby removing the older nitrogen and reducing mean nitrogen age. Estimating the mean nitrogen age can thus serve as an important tool to disentangle complex nitrogen dynamics by providing a nuanced characterization of the time scales of soil-nitrogen transformation and transport processes.

  2. EXPERIMENT STUDY AND CLINICAL OBSERVATION WITH LIGATION METHOD FOR CLOSING BRONCHIAL STUMP FOLLOWING LOBECTOMY FOR LUNG NEOPLASMS

    Institute of Scientific and Technical Information of China (English)

    Chen Keneng; Yang Guoliang; Xie Wei; Hu Minbo; Feng Ruiqing; Shi Xiaotian

    1998-01-01

    Objective: Traditional method of closing bronchial stumps after lobectomy was whole layer suture by hand or by stapler. Little is known about the ligated bronchial stump following lobectomy. To evaluate the characteristics of ligation method for closing bronchial stumps. Methods: In this study 90 lobectomies on 15 mongrel dogs and 75 bronchial stump models on fresh cadaver bronchus were performed. Multivariables comparison experimental studies were made on the results of three different closing methods: simple ligation,manual suture and stapling. Results: In the ligation group, the operation time was significantly shortened (P<0.01). The depth of stump cavity between ligation group and suture group was of no difference significantly (P>0.05). The resistance against intrabronchial pressure was greater in the ligation group than in the suture group (P<0.01). Pathological studies illustrated earlier healing of mucosal membrane with milder inflammatory reactions.In clinical practice, 121 lobectomies were successfully performed with simple ligation of the stumps.Conclusion: Simple ligation is a safe, reliable, simple, and applicable method for closing bronchial stump following lobectomies.

  3. Swimming performance, venous oxygen tension and cardiac performance of coronary-ligated rainbow trout, Oncorhynchus mykiss, exposed to progressive hypoxia

    DEFF Research Database (Denmark)

    Steffensen, J F; Farrell, A P

    1998-01-01

    (Pva) increased significantly with hypoxic swimming in sham-operated fish, there was no such increase in coronary-ligated fish. In addition, cardiac arrhythmias occurred in coronary-ligated fish at fatigue, and these fish were slower to recover from exhaustion. We believe that the venous PO2 threshold...

  4. A novel DNA deletion-ligation reaction catalyzed in vitro by a developmentally controlled activity from Tetrahymena cells.

    Science.gov (United States)

    Robinson, E K; Cohen, P D; Blackburn, E H

    1989-09-08

    Developmentally controlled genomic deletion-ligations occur during ciliate macronuclear differentiation. We have identified a novel activity in Tetrahymena cell-free extracts that efficiently catalyzes a specific set of intramolecular DNA deletion-ligation reactions. When synthetic DNA oligonucleotide substrates were used, all the deletion-ligation products resembled those formed in vivo in that they resulted from deletions between pairs of short direct repeats. The reaction is ATP-dependent, salt-sensitive, and strongly influenced by the oligonucleotide substrate sequence. The deletion-ligation activity has an apparent size of 200-500 kd, no nuclease-sensitive component, and is highly enriched in cells developing new macronuclei. The temperature inactivation profile of the activity parallels the temperature lethality profile specific for Tetrahymena cells developing new macronuclei. We suggest that this deletion-ligation activity carries out the genomic deletions in developing macronuclei in vivo.

  5. Characterization of a NADH-dependent glutamate dehydrogenase mutant of Arabidopsis demonstrates the key role of this enzyme in root carbon and nitrogen metabolism.

    Science.gov (United States)

    Fontaine, Jean-Xavier; Tercé-Laforgue, Thérèse; Armengaud, Patrick; Clément, Gilles; Renou, Jean-Pierre; Pelletier, Sandra; Catterou, Manuella; Azzopardi, Marianne; Gibon, Yves; Lea, Peter J; Hirel, Bertrand; Dubois, Frédéric

    2012-10-01

    The role of NADH-dependent glutamate dehydrogenase (GDH) was investigated by studying the physiological impact of a complete lack of enzyme activity in an Arabidopsis thaliana plant deficient in three genes encoding the enzyme. This study was conducted following the discovery that a third GDH gene is expressed in the mitochondria of the root companion cells, where all three active GDH enzyme proteins were shown to be present. A gdh1-2-3 triple mutant was constructed and exhibited major differences from the wild type in gene transcription and metabolite concentrations, and these differences appeared to originate in the roots. By placing the gdh triple mutant under continuous darkness for several days and comparing it to the wild type, the evidence strongly suggested that the main physiological function of NADH-GDH is to provide 2-oxoglutarate for the tricarboxylic acid cycle. The differences in key metabolites of the tricarboxylic acid cycle in the triple mutant versus the wild type indicated that, through metabolic processes operating mainly in roots, there was a strong impact on amino acid accumulation, in particular alanine, γ-aminobutyrate, and aspartate in both roots and leaves. These results are discussed in relation to the possible signaling and physiological functions of the enzyme at the interface of carbon and nitrogen metabolism.

  6. Characterization of a novel micro-pressure swirl reactor for removal of chemical oxygen demand and total nitrogen from domestic wastewater at low temperature.

    Science.gov (United States)

    Ren, Qingkai; Yu, Yang; Zhu, Suiyi; Bian, Dejun; Huo, Mingxin; Zhou, Dandan; Huo, Hongliang

    2017-02-06

     A novel micro-pressure swirl reactor (MPSR) was designed and applied to treat domestic wastewater at low temperature by acclimating microbial biomass with steadily decreasing temperature from 15 to 3 °C. Chemical oxygen demand (COD) was constantly removed by 85% and maintained below 50 mg L(-1) in the effluent during the process. When the air flow was controlled at 0.2 m(3) h(-1), a swirl circulation was formed in the reactor, which created a dissolved oxygen (DO) gradient with a low DO zone in the center and a high DO zone in the periphery for denitrification and nitrification. 81% of total nitrogen was removed by this reactor, in which ammonium was reduced by over 90%. However, denitrification was less effective because of the presence of low levels of oxygen. The progressively decreasing temperature favored acclimation of psychrophilic bacteria in the reactor, which replaced mesophilic bacteria in the process of treatment.

  7. Characterization of the effects of nitrogen and hydrogen passivation on SiO2/4H-SiC interface by low temperature conductance measurements

    Science.gov (United States)

    Yiyu, Wang; Zhaoyang, Peng; Huajun, Shen; Chengzhan, Li; Jia, Wu; Yachao, Tang; Yanli, Zhao; Ximing, Chen; Kean, Liu; Xinyu, Liu

    2016-02-01

    We investigate the effects of NO annealing and forming gas (FG) annealing on the electrical properties of a SiO2/SiC interface by low-temperature conductance measurements. With nitrogen passivation, the density of interface states (DIT) is significantly reduced in the entire energy range, and the shift of flatband voltage, ΔVFB, is effectively suppressed to less than 0.4 V. However, very fast states are observed after NO annealing and the response frequencies are higher than 1 MHz at room temperature. After additional FG annealing, the DIT and ΔVFB are further reduced. The values of the DIT decrease to less than 1011 cm-2 eV-1 for the energy range of EC - ET > 0.4 eV. It is suggested that the fast states in shallow energy levels originated from the N atoms accumulating at the interface by NO annealing. Though FG annealing has a limited effect on these shallow traps, hydrogen can terminate the residual Si and C dangling bonds corresponding to traps at deep energy levels and improve the interface quality further. It is indicated that NO annealing in conjunction with FG annealing will be a better post-oxidation process method for high performance SiC MOSFETs. Project supported by the National Natural Science Foundation of China (Nos. 61106080, 61275042) and the National Science and Technology Major Project of the Ministry of Science and Technology of China (No. 2013ZX02305).

  8. Facilitating Students' Review of the Chemistry of Nitrogen-Containing Heterocyclic Compounds and Their Characterization through Multistep Synthesis of Thieno[2,3-"b"]Pyridine Derivatives

    Science.gov (United States)

    Liu, Hanlin; Zaplishnyy, Vladimir; Mikhaylichenko, Lana

    2016-01-01

    A multistep synthesis of thieno[2,3-"b"]pyridine derivatives is described that is suitable for the upper-level undergraduate organic laboratory. This experiment exposes students to various hands-on experimental techniques as well as methods of product characterization such as IR and [superscript 1]H NMR spectroscopy, and…

  9. Ligation of mouse L4 and L5 spinal nerves produces robust allodynia without major motor function deficit.

    Science.gov (United States)

    Ye, Gui-Lan; Savelieva, Katerina V; Vogel, Peter; Baker, Kevin B; Mason, Sara; Lanthorn, Thomas H; Rajan, Indrani

    2015-01-01

    Spinal nerve L5/L6 ligation (SNL) in rats has become the standard for mechanistic studies of peripheral neuropathy and screening for novel analgesics. Conventional SNL in our hybrid mice resulted in a wide range of allodynia. Anatomical evaluation indicated that a variable number of lumbar vertebrae existed, resulting in L4/L5 or L5/L6 being ligated. Surprisingly, L4/L5 ligation did not result in ipsilateral hind limb paralysis and produced robust allodynia. Following a recent report that the mouse L4 neural segment is homologous with rat L5 we generated L4, L5 or both L4 and L5 (L4/L5) ligations in C57 mice after establishing a modified set of surgical landmarks. In contrast to rats, L4 ligation in these mice did not result in hind limb paralysis. Robust allodynia was observed in all three ligation groups. Nerve degeneration confirmed that L4 and L5, respectively, are primary contributors to the tibial and sural branches of the sciatic nerve in mice. A larger von Frey sensitive area reflected the wider distribution of Wallerian degeneration in the hindlimb of L4- compared to L5-ligated mice. Ligation of mouse L4 and L5 spinal nerves produces consistent, robust neuropathic pain behaviors and is suitable as a model for investigating mechanisms of neuropathic pain and for testing of novel analgesics. Gabapentin, used as a validation drug in neuropathic pain models and as a reference compound for novel analgesics, significantly reduced allodynia in the mice tested (L4/L5 ligations). Given the ease of surgery, robust allodynia, and larger von Frey sensitive area, we conclude that combined ligation of spinal nerves L4 and L5 optimizes the SNL model in mice.

  10. ANESTHESIA MANAGEMENT OF 775 GRAMS PREMATURE PATIENT DURING PDA LIGATION-A CASE REPORT

    Directory of Open Access Journals (Sweden)

    Gulsen KESKiN

    2016-03-01

    We believe that VLBW preterm infants by having multiple system failure may have PDA ligation in operating room if there is no optimum conditions in ICU by obtaining safe transport, performing ketamine in anesthesia induction and maintenance. [J Contemp Med 2016; 6(1.000: 47-50

  11. Aneurysm after surgical ligation of patent ductus arteriosus: a case report

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sung Gyu; Yang, Sang Kyu; Chi, Jung Ik; Lee, Chang Jun [National Medical Center, Seoul (Korea, Republic of)

    2002-09-01

    Patent ductus arteriosus (PDA) is one of the most common congenital heart diseases. A rare complication occurring after its surgical treatment is the development of an aneurysm, and we report the radiologic findings in a case in which this occurred after surgical ligation.

  12. SYNTHESIS OF PROTEINS BY NATIVE CHEMICAL LIGATION USING FMOC-BASED CHEMISTRY

    Energy Technology Data Exchange (ETDEWEB)

    Camarero, J A; Mitchell, A R

    2005-01-20

    C-terminal peptide {alpha}-thioesters are valuable intermediates in the synthesis/semisynthesis of proteins by native chemical ligation. They are prepared either by solid-phase peptide synthesis (SPPS) or biosynthetically by protein splicing techniques. The present paper reviews the different methods available for the chemical synthesis of peptide {alpha}-thioesters using Fmoc-based SPPS.

  13. Histamine receptors expressed in circulating progenitor cells have reciprocal actions in ligation-induced arteriosclerosis.

    Science.gov (United States)

    Yamada, Sohsuke; Wang, Ke-Yong; Tanimoto, Akihide; Guo, Xin; Nabeshima, Atsunori; Watanabe, Takeshi; Sasaguri, Yasuyuki

    2013-09-01

    Histamine is synthesized as a low-molecular-weight amine from L-histidine by histidine decarboxylase (HDC). Recently, we demonstrated that carotid artery-ligated HDC gene-deficient mice (HDC(-/-)) showed less neointimal formation than wild-type (WT) mice, indicating that histamine participates in the process of arteriosclerosis. However, little is known about the roles of histamine-specific receptors (HHRs) in arteriosclerosis. To define the roles of HHRs in arteriosclerosis, we investigated intimal remodeling in ligated carotid arteries of HHR-deficient mice (H1R(-/-) or H2R(-/-)). Quantitative analysis showed that H1R(-/-) mice had significantly less arteriosclerogenesis, whereas H2R(-/-) mice had more, as compared with WT mice. Bone marrow transplantation from H1R(-/-) or H2R(-/-) to WT mice confirmed the above observation. Furthermore, the increased expression of monocyte chemoattractant protein (MCP-1), platelet-derived growth factor (PDGF), adhesion molecules and liver X receptor (LXR)-related inflammatory signaling factors, including Toll-like receptor (TLR3), interleukin-1 receptor (IL-1R) and tumor necrosis factor receptor (TNF-R), was consistent with the arteriosclerotic phenotype of H2R(-/-) mice. Peripheral progenitor cells in H2R(-/-) mice accelerate ligation-induced arteriosclerosis through their regulation of MCP-1, PDGF, adhesion molecules and LXR-related inflammatory signaling factors. In contrast, peripheral progenitor cells act to suppress arteriosclerosis in H1R(-/-) mice, indicating that HHRs reciprocally regulate inflammation in the ligation-induced arteriosclerosis.

  14. Ligation of pork skin gelatin with glucose moieties affects the junction zones in gelled networks

    NARCIS (Netherlands)

    Baigts Allende, Diana; Jongh, de H.H.J.

    2015-01-01

    This study aims to investigate the role of the ligation of steric moieties on the formation of junction zones during network formation of gelatin gels. The molecular conformational propensities, heat stability and mechanical properties of gradually chemically modified pork skin gelatin have been

  15. Comparative study of proton pump inhibitors on dexamethasone plus pylorus ligation induced ulcer model in rats

    Directory of Open Access Journals (Sweden)

    Thippeswamy A. H. M.

    2010-01-01

    Full Text Available The present study was designed to compare ulcer protective effect of proton pump inhibitors viz. omeprazole, rabeprazole and lansoprazole against dexamethasone plus pylorus ligation induced ulcer model. Dexamethasone (5 mg/kg was used as an ulcerogen. Dexamethasone suspended in 1% CMC in water was given orally to all the rats 15 min after the pylorus ligation. Omeprazole (20 mg/kg, rabeprazole (20 mg/kg, and lansoprazole (20 mg/kg were administered by oral route 30 min prior to ligation was used for ulcer protective studies, gastric secretion and mucosal studies. Effects of proton pump inhibitors were determined by the evaluation of various biochemical parameters such as ulcer index, free and total acidity, gastric pH, mucin, pepsin and total proteins. Oral administration of proton pump inhibitors showed significant reduction in gastric acid secretion and ulcer protective activity against dexamethasone plus pylorus ligation induced ulcer model. The % protection of omeprazole, rabeprazole and lansoprazole was 84.04, 89.36 and 79.78, respectively. Rabeprazole significantly inhibited the acid-pepsin secretion and increased the gastric mucin secretion. The observations made in the present study suggest that rabeprazole is the most effective gastric antisecretory and ulcer healing agent as compared to omeprazole and lansoprazole.

  16. Gingival response in orthodontic patients: Comparative study between self-ligating and conventional brackets.

    Science.gov (United States)

    Folco, Alejandra A; Benítez-Rogé, Sandra C; Iglesias, Marina; Calabrese, Diana; Pelizardi, Cristina; Rosa, Alcira; Brusca, Marisa I; Hecht, Pedro; Mateu, María E

    2014-01-01

    Orthodontic brackets contribute to the accumulation of bacterial plaque on tooth surfaces because they hinder oral hygiene. In contrast to conventional brackets, self-ligating brackets do not require additional parts to support the arches, thus improving dental hygiene. The aim of this study was to compare the gingival response in orthodontic patients wearing self-ligating or conventional brackets. A sample of 22 patients aged 16 to 30 years was divided into two groups: Group A, treated with selfligating brackets (Damon system) and Group B, treated with conventional brackets (Roth technique). The following were assessed during the treatment: Plaque Index (PI), Gingival Index (GI) and Probing Depth (PD), and sub-gingival samples were taken from teeth 14/24 for microbiological observation. No statistically significant difference was found between Groups A and B; p>0.05 (sign-ranked) or between PI, GI and PD at the different times (Friedman's Analysis of Variance), even though the indices were found to increase at 14 days, particularly for self-ligating brackets. The quantity and quality of microorganisms present were compatible with health on days 0, 28 and 56. As from day 14 there is a predominance of microbiota compatible with gingivitis in both groups. In the samples studied, orthodontic treatment increases bacterial plaque and inflammatory gingival response, but gingival-periodontal health can be maintained with adequate basic therapy. Self-ligating and conventional brackets produced similar gingival response.

  17. Catecholamine-resistant hypotension and myocardial performance following patent ductus arteriosus ligation.

    LENUS (Irish Health Repository)

    Noori, S

    2014-08-14

    Objective:We performed a multicenter study of preterm infants, who were about to undergo patent ductus arteriosus ligation, to determine whether echocardiographic indices of impaired myocardial performance were associated with subsequent development of catecholamine-resistant hypotension following ligation.Study Design:A standardized treatment approach for hypotension was followed at each center. Infants were considered to have catecholamine-resistant hypotension if their dopamine infusion was >15 μg kg(-1)min(-1). Echocardiograms and cortisol measurements were obtained between 6 and 14 h after the ligation (prior to the presence of catecholamine-resistant hypotension).Result:Forty-five infants were enrolled, 10 received catecholamines (6 were catecholamine-responsive and 4 developed catecholamine-resistant hypotension). Catecholamine-resistant hypotension was not associated with decreased preload, shortening fraction or ventricular output. Infants with catecholamine-resistant hypotension had significantly lower levels of systemic vascular resistance and postoperative cortisol concentration.Conclusion:We speculate that low cortisol levels and impaired vascular tone may have a more important role than impaired cardiac performance in post-ligation catecholamine-resistant hypotension.Journal of Perinatology advance online publication, 14 August 2014; doi:10.1038\\/jp.2014.151.

  18. Ligation of the thoracic duct for the treatment of chylothorax in heart diseases

    Directory of Open Access Journals (Sweden)

    Pêgo-Fernandes Paulo M.

    2003-01-01

    Full Text Available In children, chylothorax occurs mainly after cardiac and thoracic surgeries. One of the recommended postsurgery treatments is ligation of the thoracic tract, when all other conservative treatments have failed. We report 4 cases of chylothorax in patients who were successfully treated with this approach, which resulted in a decrease in pleural drainage without recurrent chylothorax.

  19. A revised mechanism for the α-ketoacid hydroxylamine amide forming ligations.

    Science.gov (United States)

    Patil, Mahendra

    2017-01-04

    Computational investigations of the α-ketoacid-hydroxylamine amide-forming (KAHA) ligation of O-unsubstituted (type-I) and O-benzoyl substituted (type-II) hydroxylamine have revealed a distinct mechanistic pathway for the KAHA ligation reactions. Instead of a pathway involving lactone and oxiridine intermediates for the reaction of O-unsubstituted hydroxylamine and ketoacids (type-I KAHA), as had been proposed in the experimental studies, the computational results favor the pathway which involves migration of the hydroxy group (-OH) to the adjacent carbon in one of the key steps. The new pathway for the type I KAHA reaction explains the distribution of the (18)O label in the final product (amide) that is observed in (18)O labeling experiments of type-I ligation reaction. A coherent mechanistic course is also identified for the reaction of O-benzoyl substituted hydroxylamine and ketoacid (type II KAHA) reactions. The proposed pathway for the type-II KAHA ligation reaction proceeds with the retention of an oxygen atom of the keto group of ketoacids rather than hydroxylamine in the final product (amide). These findings are consistent with the results of (18)O labeling experiments performed by Bode and coworkers on the KAHA reactions.

  20. Actual versus theoretical torsional play in conventional and self-ligating bracket systems

    DEFF Research Database (Denmark)

    Dalstra, Michel; Eriksen, Henrik; Bergamini, Chiara;

    2015-01-01

    Abstract Objective: The aim of this study was to assess the amount of torsional play in 32 commercially available self-ligating and conventional 0·018-inch and 0·022-inch bracket systems in relation to 0·017×0·022-inch and 0·019×0·025-inch stainless steel wires, respectively, and compare the resu...

  1. Opening and closure forces of sliding mechanisms of different self-ligating brackets

    Directory of Open Access Journals (Sweden)

    Paola GANDINI

    2013-06-01

    Full Text Available Self-ligating brackets engage the wire by means of a slide mechanism. Forces that have to be applied to open and close the sliding mechanism of brackets are still unknown. Objective The aim of this study was to measure and compare the opening and closure forces of different self-ligating brackets. Material and Methods Three different stainless steel self-ligating brackets (Carriere LX, Ortho Organizers; F1000, Leone; Damon Q, Ormco were tested. For each different bracket, 20 maxillary right central incisors and 20 mandibular right central incisors were used. Opening and closure forces were measured using an Instron Universal Testing Machine. Statistical analysis was performed and ANOVA and Tukey tests were carried out. Results Opening forces were registered between 1.1 N and 5.6 N, whereas closure forces were recorded between 1.57 N and 4.87 N. Significant differences were detected among the different brackets and between the two prescriptions tested. Conclusion The knowledge of different opening and closure forces of self-ligating brackets can help the orthodontist in the clinical management of these devices.

  2. Multiplex Ligation-Dependent Probe Amplification of Uveal Melanoma : Correlation with Metastatic Death

    NARCIS (Netherlands)

    Damato, Bertil; Dopierala, Justyna; Klaasen, Annelies; van Dijk, Marcory; Sibbring, Julie; Coupland, Sarah E.

    2009-01-01

    PURPOSE. To evaluate multiplex ligation-dependent probe amplification (MLPA) of uveal melanoma as a predictive tool for metastatic death. METHODS. Uveal melanoma specimens of 73 patients treated between 1998 and 2000 were included. DNA samples were analyzed with MLPA evaluating 31 loci on chromosome

  3. Minimal access microsurgical ligation of spinal dural arteriovenous fistula with tubular retractor

    Directory of Open Access Journals (Sweden)

    Anderson Chun On Tsang

    2015-01-01

    Conclusion: With accurate localization of the fistulous point in each patient, only a hemilaminectomy and a small dura opening were required using the tube-assisted technique. This allows direct visualization and ligation of the fistulous point while minimizing postoperative morbidities.

  4. Prevalence and type of pain during conventional and self-ligating orthodontic treatment.

    Science.gov (United States)

    Tecco, Simona; D'Attilio, Michele; Tetè, Stefano; Festa, Felice

    2009-08-01

    This study investigated the prevalence and type of pain experienced during orthodontic treatment in 30 subjects (12 males, 18 females, aged 12-18 years) with crowding. Fifteen patients were treated with conventional brackets (Victory Series) and 15 with self-ligating brackets (Damon SL II). The first archwire for all patients was a 0.014 inch nickel-titanium (NiTi) archwire with a force of approximately 100 g. Conventional brackets were ligated with elastomeric modules. A visual analogue scale (VAS) was used daily to assess the intensity of pain; the use of pain medication was also reported in a specially designed daybook for a total period of 3 months. Pearson's chi-square was used to investigate the difference between groups in the frequency of pain experience, its nature, and the use of analgesia. Non-parametric statistics (Mann-Whitney U-test) were computed to compare pain intensity between the groups. To investigate reported pain assessments, Friedman's two-way analysis of variance was used and the differences were estimated using Wilcoxon's signed-rank test. The results showed that pain was reported for a period of 9 days after archwire insertion. Patients treated with self-ligating brackets reported the highest pain intensity on the day following placement of the first archwire (VAS mean = 42.6), while those treated with conventional brackets experienced the greatest pain intensity at placement of the first archwire (VAS mean = 52) and after the second orthodontic appointment (VAS mean = 59.6). Analgesics were used by 16.5 per cent of patients treated with self-ligating brackets and by 10 per cent of those treated with conventional brackets, most often during the first 2 days after archwire placement. Patients treated with conventional brackets reported significantly more 'constant' pain than those treated with self-ligating brackets who complained of 'chewing/biting' pain. Pain appears to be common during orthodontic treatment but perhaps less intense when

  5. Inhibition of lung metastasis of osteosarcoma cell line POS-1 transplanted into mice by thigh ligation.

    Science.gov (United States)

    Kamijo, Akira; Koshino, Tomihisa; Uesugi, Masaaki; Nitto, Hironori; Saito, Tomoyuki

    2002-12-15

    Using a model with external ligation of the thigh, the effect of ischemia-reperfusion injury on tumor growth and the activity of lung metastasis was investigated in mice inoculated a spontaneous murine osteosarcoma cell line (POS-1) in vivo. POS-1 cell suspension was inoculated into the right hind footpad of 70 mice. Four weeks after inoculation, the ipsilateral thigh was ligated for 3 h in 15 mice and the contralateral thigh in 15 mice. Another ten mice were inoculated with POS-1 without ligating the thigh. The number of metastatic foci on the lung surface 6 weeks after inoculation was 2.29+/-0.98 (mean+/-SE) foci/lungs in mice with ipsilateral ligation and 6.25+/-2.41 in mice with contralateral ligation, which were significantly lower than control (13.40+/-1.42 in mice no ligation) (P<0.01). The number of metastatic foci on the lung surface in mice with intraperitoneal injection of superoxide dismutase (SOD) and catalase was 3.25+/-0.65 (mean+/-SE) foci/lungs in mice with ligation which was significantly greater than that in mice without SOD and catalase injection 1.29+/-0.97 (P=0.04). Cell viability was 9.12+/-4.07% with 100 microM H(2)O(2) in 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay. It revealed that at concentrations of 100 microM H(2)O(2) or higher was cytotoxic to POS-1. In cell invasion assay, the number of invading cells with 10 microM H(2)O(2) was 2.80+/-0.53 cells/field, which was significantly lower than control (5.93+/-0.18) (mean+/-SE), indicating that low-dose H(2)O(2) suppressed invasion of POS-1. These results suggested that reperfusion injury had selective cytotoxicity to POS-1 through producing reactive oxygen species. Activated oxygen was considered to inhibit the regional growth and the ability of lung metastasis of POS-1 cells.

  6. An improved method for utilization of peptide substrates for antibody characterization and enzymatic assays.

    Science.gov (United States)

    Ghosh, Inca; Sun, Luo; Evans, Thomas C; Xu, Ming-Qun

    2004-10-01

    Synthetic peptides have become an important tool in antibody production and enzyme characterization. The small size of peptides, however, has hindered their use in assays systems, such as Western blots, and as immunogens. Here, we present a facile method to improve the properties of peptides for multiple applications by ligating the peptides to intein-generated carrier proteins. The stoichiometric ligation of peptide and carrier achieved by intein-mediated protein ligation (IPL) results in the ligation product migrating as a single band on a SDS-PAGE gel. The carrier proteins, HhaI methylase (M.HhaI) and maltose-binding protein (MBP), were ligated to various peptides; the ligated carrier-peptide products gave sharp, reproducible bands when used as positive controls for antibodies raised against the same peptides during Western blot analysis. We further show that ligation of the peptide antigens to a different thioester-tagged carrier protein, paramyosin, produced immunogens for the production of antisera in rabbits or mice. Furthermore, we demonstrate the generation of a substrate for enzymatic assays by ligating a peptide containing the phosphorylation site for Abl protein tyrosine kinase to a carrier protein. This carrier-peptide protein was used as a kinase substrate that could easily be tested for phosphorylation using a phosphotyrosine antibody in Western blot analysis. These techniques do not require sophisticated equipment, reagents, or skills thereby providing a simple method for research and development.

  7. Radiological study on the change of duct-ligated parotid gland

    Energy Technology Data Exchange (ETDEWEB)

    Ohnishi, Takashi (Higashi Nippon Gakuen Univ., Tobetsu, Hokkaido (Japan). School of Dentistry)

    1994-07-01

    The change of the parotid gland with time following ligation of the main duct was investigated. The duct-ligated parotid gland in rabbit was examined by salivary gland scintigraphy with [sup 99m]Tc-pertechnetate ([sup 99m]TcO[sub 4][sup -]), sialography and microscopic observation. The third day after ligation of the main duct, the outward form of the parotid gland on the static scintigram was not well-defined. On the seventh day, [sup 99m]TcO[sub 4][sup -] accumulation was decreased slightly. On the 14th day, atrophy of the parotid gland occurred. The degree of atrophy produced by ligation increases as the duration of the ligation increases. On the 42nd day, the presence of the parotid gland was not recorded practically. The main duct was dilated on the third day. On the seventh day, the intraglandular ducts were bent and strictured. Disappearance of the peripheral duct and atrophy of the parotid gland parenchyma was observed. On microscopic observation, the intraglandular tributaries and the lumen were dilated on the third day. And the reticular fiber was observed that was irregularly formed in parts. The acinar cells were pressed by large and small dilated lumen on the seventh day. On the 14th day, the collagenous fiber around the acini and the duct was increased still more. In addition, fibrosis of the lobule interspace was observed. The degree of atrophy of the acini and lobule was increased maximally on the 42nd day. These results of the salivary gland scintigraphy closely connected with sialograms and microscopic findings. The parotid gland tissue decreases and changings of the duct system were indicated by these imaging methods in detail. (author).

  8. Routine chest drainage after patent ductus arteriosis ligation is not necessary.

    Directory of Open Access Journals (Sweden)

    Samuel Kai San YAPP

    2010-12-01

    Full Text Available Introduction: Chest drain insertion after surgical patent ductus arteriosus (PDA ligation creates significant morbidities in terms of pain, pleural space infection, reduced mobility as well as prolonged hospital stay. We investigated the safety and efficacy of performing drainless thoracotomy closure following PDA ligation in a paediatric population. Materials and Methods: Retrospective analysis of data collected from 13 paediatric patients undergoing PDA ligation at RIPAS hospital by a single surgeon over a period of five years (2001 to 2006 was performed. All continuous data were presented as mean ± standard deviation. Results: PDA ligation was performed via a left thoracotomy in 13 pediatric patients with a mean age of 2.24 ± 2.03 years (ten females and three males. Mean duration of the procedures was 67 ± 12 minutes. There was minimal blood loss and no transfusion was required. Postoperatively, ten patients required only oral paracetamol for pain relief. Two patients required additional non steroidal anti-inflammatory drugs (NSAIDs. One patient had one dose of pethidine immediately post-operatively. Post-operative chest radiographs confirmed full expansion of the left lung except in one patient who had a small apical pneumothorax. Two other patients developed mild surgical emphysema despite full expansion of the left lung. All three cases resolved spontaneously after a day. Median post-operative stay was two days. There were no cases of left recurrent nerve injuries and no mortality. Conclusion: Routine chest drainage is not necessary following uncomplicated surgical PDA ligation and patients recovered quicker and are discharge earlier.

  9. Use of rigid tubal ligation scope: Serendipity in laparoscopic common bile duct exploration

    Directory of Open Access Journals (Sweden)

    Manash Ranjan Sahoo

    2014-01-01

    Full Text Available Aim : To assess the feasibility, safety of rigid tubal ligation scope in laparoscopic common bile duct (CBD exploration. Materials and Methods: Rigid nephroscope was used for laparoscopic CBD exploration until one day we tried the same with the rigid tubal ligation scope, which was passed easily into CBD both proximally and distally visualising the interior of the duct for presence of stone that were removed using endoscopic retrograde cholangiopancreaticography (ERCP basket. This serendipity led us to use this scope for numerous patients from then on. A total of 62 patients, including male and female, underwent laparoscopic CBD exploration after choledochotomy with rigid tubal ligation scope between March 2007 and December 2012 followed by cholecystectomy. All the patients had both cholelithiasis and choledocholithiasis with minimum duct diameter of 12 mm. A total of 48 patients were given T-tube through choledochotomy and closed, and the remaining 14 patients had primary closure of choledochotomy. Results: There were no intra-operative complications in any of the patients like CBD injury or portal vein injury. Post-operatively graded clamping of T-tube was done and was removed after 15 days in the patients who were given T-tube. None had retained the stone after T-tube cholangiography, which was done before removing the tube. Mean duration of follow up was 6 months. No patients had any complaints during the follow up. Conclusion: Laparoscopic CBD exploration is also feasible with rigid tubal ligation scope. With experienced surgeons, CBD injury is very minimal and stone clearance can be achieved in almost all patients. This rigid tubal ligation scope can be an alternative to other rigid and flexible scopes.

  10. Extrahepatic portal venous obstruction: The effects of early ligation of splenic artery during splenectomy

    Directory of Open Access Journals (Sweden)

    Gazula Suhasini

    2009-01-01

    Full Text Available Aim: To objectively demonstrate the gain in blood volume and blood components following early ligation of splenic artery during splenectomy and splenorenal shunts in children with extra hepatic portal venous obstruction (EHPVO. Methods: Twenty-eight children (20 males and 8 females, mean age: 9.9 (±3.2 years with EHPVO and hypersplenism were recruited. We followed a protocol of systematically locating and ligating the splenic artery first, followed by a 30-minute waiting period to allow the massive spleen to decongest via the splenic vein and venous collaterals and then completing the splenectomy by standard procedure. No intravenous fluid was administered during this 30-minute period. Blood samples were drawn just prior to splenic artery ligation and soon after splenectomy for the estimation of hematological and biochemical parameters. Results: We noticed a highly significant increase in the hemoglobin, hematocrit, leukocyte, platelet, and RBC counts by early ligation of the splenic artery (p < 0.0004. The gain in hemoglobin and hematocrit was equivalent to a transfusion of atleast 100-150 ml of packed RBC. The increase in platelet count was equivalent to a platelet transfusion of atleast 4 units of platelet concentrates in an adult. There is a positive correlation between the splenic weight and the platelet gain (p= 0.0568 and the splenic volume on preoperative imaging and the platelet gain (p= 0.0251. Conclusion: Early ligation of the splenic artery during splenectomy results in passive splenic decongestion and thereby a significant gain in blood components. This protocol appears to be a feasible blood conservation method to avoid blood transfusions in this group of hypersplenic EHPVO patients.

  11. Activation of neurotrophins in lumbar dorsal root probably contributes to neuropathic pain after spinal nerve ligation

    Science.gov (United States)

    Kazemi, Abdolreza; Rahmati, Masoud; Eslami, Rasoul; Sheibani, Vahid

    2017-01-01

    Objective(s): Neurotrophins (NTs) exert various effects on neuronal system. Growing evidence indicates that NTs are involved in the pathophysiology of neuropathic pain. However, the exact role of these proteins in modulating nociceptive signaling requires being defined. Thus, the aim of this study was to evaluate the effects of spinal nerve ligation (SNL) on NTs activation in the lumbar dorsal root. Materials and Methods: Ten male Wistar rats were randomly assigned to two groups: tight ligation of the L5 spinal nerve (SNL: n=5) and Sham (n=5). In order to produce neuropathic pain, the L5 spinal nerve was tightly ligated (SNL). Then, allodynia and hyperalgesia tests were conducted weekly. After 4 weeks, tissue samples were taken from the two groups for laboratory evaluations. Here, Real-Time PCR quantity method was used for measuring NTs gene expression levels. Results: SNL resulted in a significant weight loss in the soleus muscle (Pthermal hyperalgesia thresholds (respectively, P<0.05; P<0.05). Also, NGF, NT-4, NT-3, TrkA, TrkB and TrkC expression were up-regulated following spinal nerve ligation group (respectively, P=0.025, P=0.013, P=0.001, P=0.002, P<0.001, P=001) (respectively, 4.7, 5.2, 7.5, 5.1, 7.2, 6.2 folds). Conclusion: The present study provides new evidence that neuropathic pain induced by spinal nerve ligation probably activates NTs and Trk receptors expression in DRG. However, further studies are needed to better elucidate the role of NTs in a neuropathic pain. PMID:28133521

  12. A new technique of combined endoscopic sclerotherapy and ligation for variceal bleeding

    Institute of Scientific and Technical Information of China (English)

    Radha K. Dhiman; Yogesh K. Chawla

    2003-01-01

    AIM: To develop a technique of combined endoscopic sclerotherapy and ligation (ESL) in which both techniques of endoscopic sclerotherapy (ES) and endoscopic variceal ligation (EVL) can be optimally used.METHODS: ESL was performed in 10 patients (age 46.4±7.9;9 males, 1 female) with cirrhosis of liver using sclerotherapy needle and Speedband, Superview multiple band ligater (Boston Scientific, Microvasive, Watertown, MA). A single band was placed 5-10 cm proximal to the gastro-esophageal junction over each varix from proximal to distal margin,followed by intravariceal injection of 1.5 % ethoxysclerol (4 ml each) 2 to 3 cm proximal to the gastroesophageal junction on the ligated varices distal to deployed band. EVL was then performed at the injection site. Similarly other varices were also injected and ligated from distal to proximally. In the subsequent sessions, ES alone was performed to sclerose small varices at the gastroesophageal junction.RESULTS: ESL was successfully performed in all patients.A median of 3 (ESL 1, ES 2) sessions (ranged 1-4) were required to eradicate the varices in 9 (90 %) of 10 patients.Recurrence of varices without bleed was seen in 1 patient during a mean follow-up of 10.3 months (ranged 6-15).Two patients died of liver failure. None died of variceal bleeding. None of the patients had procedure related complications.CONCLUSION: ESL may be useful in the fast eradication of esophageal varices. However, randomised controlled trials are required to find out its relative efficacy and impact on variceal recurrence in comparison to ES or EVL.

  13. Process characterization and influence of alternative carbon sources and carbon-to-nitrogen ratio on organic acid production by Aspergillus oryzae DSM1863.

    Science.gov (United States)

    Ochsenreither, Katrin; Fischer, Christian; Neumann, Anke; Syldatk, Christoph

    2014-06-01

    L-Malic acid and fumaric acid are C4 dicarboxylic organic acids and considered as promising chemical building blocks. They can be applied as food preservatives and acidulants in rust removal and as polymerization starter units. Molds of the genus Aspergillus are able to produce malic acid in large quantities from glucose and other carbon sources. In order to enhance the production potential of Aspergillus oryzae DSM 1863, production and consumption rates in an established bioreactor batch-process based on glucose were determined. At 35 °C, up to 42 g/L malic acid was produced in a 168-h batch process with fumaric acid as a by-product. In prolonged shaking flask experiments (353 h), the suitability of the alternative carbon sources xylose and glycerol at a carbon-to-nitrogen (C/N) ratio of 200:1 and the influence of different C/N ratios in glucose cultivations were tested. When using glucose, 58.2 g/L malic acid and 4.2 g/L fumaric acid were produced. When applying xylose or glycerol, both organic acids are produced but the formation of malic acid decreased to 45.4 and 39.4 g/L, respectively. Whereas the fumaric acid concentration was not significantly altered when cultivating with xylose (4.5 g/L), it is clearly enhanced by using glycerol (9.3 g/L). When using glucose as a carbon source, an increase or decrease of the C/N ratio did not influence malic acid production but had an enormous influence on fumaric acid production. The highest fumaric acid concentrations were determined at the highest C/N ratio (300:1, 8.44 g/L) and lowest at the lowest C/N ratio (100:1, 0.7 g/L).

  14. Electrical characterization of deep levels created by bombarding nitrogen-doped 4H-SiC with alpha-particle irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Omotoso, Ezekiel, E-mail: ezekiel.omotoso@up.ac.za [Department of Physics, University of Pretoria, Private Bag X20, Hatfield 0028 (South Africa); Departments of Physics, Obafemi Awolowo University, Ile-Ife 220005 (Nigeria); Meyer, Walter E., E-mail: wmeyer@up.ac.za [Department of Physics, University of Pretoria, Private Bag X20, Hatfield 0028 (South Africa); Auret, F. Danie; Paradzah, Alexander T.; Legodi, Matshisa J. [Department of Physics, University of Pretoria, Private Bag X20, Hatfield 0028 (South Africa)

    2016-03-15

    Deep-level transient spectroscopy (DLTS) and Laplace-DLTS were used to investigate the effect of alpha-particle irradiation on the electrical properties of nitrogen-doped 4H-SiC. The samples were bombarded with alpha-particles at room temperature (300 K) using an americium-241 ({sup 241}Am) radionuclide source. DLTS revealed the presence of four deep levels in the as-grown samples, E{sub 0.09}, E{sub 0.11}, E{sub 0.16} and E{sub 0.65}. After irradiation with a fluence of 4.1 × 10{sup 10} alpha-particles-cm{sup −2}, DLTS measurements indicated the presence of two new deep levels, E{sub 0.39} and E{sub 0.62} with energy levels, E{sub C} – 0.39 eV and E{sub C} – 0.62 eV, with an apparent capture cross sections of 2 × 10{sup −16} and 2 × 10{sup −14} cm{sup 2}, respectively. Furthermore, irradiation with fluence of 8.9 × 10{sup 10} alpha-particles-cm{sup −2} resulted in the disappearance of shallow defects due to a lowering of the Fermi level. These defects re-appeared after annealing at 300 °C for 20 min. Defects, E{sub 0.39} and E{sub 0.42} with close emission rates were attributed to silicon or carbon vacancy and could only be separated by using high resolution Laplace-DLTS. The DLTS peaks at E{sub C} – (0.55–0.70) eV (known as Z{sub 1}/Z{sub 2}) were attributed to an isolated carbon vacancy (V{sub C}).

  15. Thalassemia in Western Australia: 11 novel deletions characterized by Multiplex Ligation-dependent Probe Amplification.

    NARCIS (Netherlands)

    Phylipsen, M.; Prior, J.F.; Lim, E.; Lingam, N.; Vogelaar, I.P.; Giordano, P.C.; Finlayson, J.; Harteveld, C.L.

    2010-01-01

    The number of immigrants in Western Australia from many different areas where hemoglobinopathies are endemic has increased dramatically since the 1970s. Therefore, many different thalassemia mutations have been introduced in the country, which add a technological diagnostic problem to the serious bu

  16. Synthesis, characterization and crystal structure of a 2-(diethylaminomethylindole ligated dimethylaluminium complex

    Directory of Open Access Journals (Sweden)

    Logan E. Shephard

    2015-10-01

    Full Text Available The title compound, [Al(CH32(C13H17N2] (systematic name; {2-[(diethylaminomethyl]indol-1-yl-κ2N,N′}dimethylaluminium, was prepared by methane elimination from the reaction of 2-(diethylaminomethylindole and trimethylaluminium. The complex crystallizes readily from a concentrated toluene solution in high yield. The asymmetric unit contains two crystallographically independent molecules. Each molecule has a four-coordinate aluminium atom that has pseudo-tetrahedral geometry. C—H...π interactions link the independent molecules into chains extending along the b-axis direction.

  17. 微污染黄浦江水溶解性有机氮的分子组成特性分析%Characterization of Dissolved Organic Nitrogen in Micro-polluted Huangpu River Water

    Institute of Scientific and Technical Information of China (English)

    荣蓉; 徐斌; 林琳; 胡晨燕; 夏圣骥; 高乃云; 叶涛; 李大鹏

    2013-01-01

    Dissolved organic matters in micro-polluted raw water from Huangpu River were concentrated and separated using reverse osmosis process and ion exchange technology. The molecular weight distribution and hydrophilic-hydrophobic characteristics of dissolved organic nitrogen ( DON) were analyzed , and the composition of DON was characterized by hydrogen isotope nuclear magnetic resonance, three-dimensional fluorescence spectrum and Fourier transform infrared spectroscopy. The results showed that DON in the raw water was mainly composed of fractions with small molecular weight, and the average molecular weight of DON was slightly higher than that of DOC and UV254. Neutral hydrophilic components showed the highest percentage of organic nitrogen, which was obviously higher than that of DOC and UV254. Protein-like organies, amino compounds and aromatic compounds were the main contributions to DON in the raw water. Moreover, DON also consisted of nitrogen-hydrogen compounds, fatty hydrocarbon compounds, saturated hydrocarbons and so on.%以微污染黄浦江原水作为研究对象,采用反渗透工艺和离子交换技术对水中溶解性有机物进行浓缩和分离,分析了溶解性有机氮(DON)的分子质量和亲、疏水性分布规律,并采用氢同位素的核磁共振法、三维荧光光谱分析法和傅里叶变换红外光谱法表征了DON的组成.结果表明,原水中的DON以小分子为主,其平均分子质量略大于以DOC和UV254表征的有机物;DON的中性亲水性组分所占比例最高,明显大于DOC和UV254;类蛋白类有机物、胺基类、芳香类化合物对DON的贡献较大;原水中的DON包含有氮氢类化合物、脂肪烃有机物、饱和碳氢化合物等.

  18. Cascading costs: An economic nitrogen cycle

    Institute of Scientific and Technical Information of China (English)

    William R. Moomaw; Melissa B. L. Birch

    2005-01-01

    The chemical nitrogen cycle is becoming better characterized in terms of fluxes and reservoirs on a variety of scales. Galloway has demonstrated that reactive nitrogen can cascade through multiple ecosystems causing environmental damage at each stage before being denitrifled to N2. We propose to construct a parallel economic nitrogen cascade (ENC) in which economic impacts of nitrogen fluxes can be estimated by the costs associated with each stage of the chemical cascade. Using economic data for the benefits of damage avoided and costs of mitigation in the Chesapeake Bay basin, we have constructed an economic nitrogen cascade for the region. Since a single tonne of nitrogen can cascade through the system, the costs also cascade.Therefore evaluating the benefits of mitigating a tonne of reactive nitrogen released needs to consider the damage avoided in all of the ecosystems through which that tonne would cascade.The analysis reveals that it is most cost effective to remove a tonne of nitrogen coming from combustion since it has the greatest impact on human health and creates cascading damage through the atmospheric, terrestrial, aquatic and coastal ecosystems. We will discuss the implications of this analysis for determining the most cost effective policy option for achieving environmental quality goals.

  19. Non-histone chromosomal proteins HMG1 and 2 enhance ligation reaction of DNA double-strand breaks.

    Science.gov (United States)

    Nagaki, S; Yamamoto, M; Yumoto, Y; Shirakawa, H; Yoshida, M; Teraoka, H

    1998-05-08

    DNA ligase IV in a complex with XRCC4 is responsible for DNA end-joining in repair of DNA double-strand breaks (DSB) and V(D)J recombination. We found that non-histone chromosomal high mobility group (HMG) proteins 1 and 2 enhanced the ligation of linearized pUC119 DNA with DNA ligase IV from rat liver nuclear extract. Intra-molecular and inter-molecular ligations of cohesive-ended and blunt-ended DNA were markedly stimulated by HMG1 and 2. Recombinant HMG2-domain A, B, and (A + B) polypeptides were similarly, but non-identically, effective for the stimulation of DSB ligation reaction. Ligation of single-strand breaks (nicks) was only slightly activated by the HMG proteins. The DNA end-binding Ku protein singly or in combination with the catalytic component of DNA-dependent protein kinase (DNA-PK) as the DNA-PK holoenzyme was ineffective for the ligation of linearized pUC119 DNA. Although the stimulatory effect of HMG1 and 2 on ligation of DSB in vitro was not specific to DNA ligase IV, these results suggest that HMG1 and 2 are involved in the final ligation step in DNA end-joining processes of DSB repair and V(D)J recombination.

  20. Mutational Analysis of Bacterial NAD+-dependent DNA Ligase:Role of Motif Ⅳ in Ligation Catalysis

    Institute of Scientific and Technical Information of China (English)

    Hong FENG

    2007-01-01

    The bacterial DNA ligase as a multiple domain protein is involved in DNA replication, repair and recombination. Its catalysis of ligation can be divided into three steps. To delineate the roles of amino acid residues in motif Ⅳ in ligation catalysis, site-directed mutants were constructed in a bacterial NAD+-dependent DNA ligase from Thermus sp. TAK16D. It was shown that four conserved residues (D286, G287, V289 and K291) in motif Ⅳ had significant roles on the overall ligation. Under single turnover conditions, the observed apparent rates of D286E, G287A, V289I and K291R mutants were clearly reduced compared with that of WT ligase on both match and mismatch nicked substrates. The effects of D286E mutation on overall ligation may not only be ascribed to the third step. The G287A mutation has a major effect on the second step. The effects of V289I and K291R mutation on overall ligation are not on the third step, perhaps other aspects, such as conformation change of ligase protein in ligation catalysis, are involved. Moreover, the amino acid substitutions of above four residues were more sensitive on mismatch nicked substrate, indicating an enhanced ligation fidelity.

  1. Plaque accumulation and Streptococcus mutans levels around self-ligating bracket clips and elastomeric modules: A randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Dhaval Fadia

    2015-01-01

    Full Text Available Aim: To determine the effect of two different ligating systems that is, elastomeric modules and self-ligating (SL bracket systems (Smartclip - 3M Unitek with respect to harboring bacterial plaque in fixed orthodontic treatment. Objectives: To assess, evaluate, and compare the amount of plaque accumulation and Streptococcus mutans colonization around elastomeric ligation and SL clips in the smart clip appliance. Materials and Methods: A total of 111 orthodontic patients scheduled for fixed orthodontic treatments were selected for this split maxillary arch study. All the patients were bonded with smart-clip (3M Unitek SL brackets, and the wire was placed into the bracket slots, on the randomly selected hemi arch, elastomeric modules were placed for the study to be conducted. Microbial and periodontal plaque accumulation was recorded at 3-time intervals post ligation. Plaque index-by Silness and Loe, modified Quigely Hein index, bleeding on probing were evaluated, and biofilm was collected from the tooth surface after 30 days and placed in petri dishes containing Mitis Salivarius agar for bacterial culturing. Result: It was observed that the side where ligation was done with elastomeric modules accumulated more plaque and increase in S. mutans colony forming units as compared to the side without external ligation (P < 0.05. Conclusion: Reduced bacterial colonization and better plaque control was seen with SL orthodontic bracket appliance system as compared to conventional ligation method.

  2. Serum markers of the extracellular matrix remodelling reflect antifibrotic therapy in bile-duct ligated rats.

    Directory of Open Access Journals (Sweden)

    Robert eSchierwagen

    2013-07-01

    Full Text Available BackgroundProgression of liver fibrosis is characterized by synthesis and degradation of extracellular matrix (ECM. Matrix-metalloproteinases (MMP cleave collagen fibers at a specific site and thereby generate soluble fragments of ECM (neo-epitopes. The levels of these neo-epitopes might reflect the stage of liver fibrosis and may allow monitoring of anti-fibrotic therapies. Here we analyzed these neo-epitopes as read-out for a liver directed therapy with statins.MethodsBile duct ligation (BDL was performed on wildtype rats, which received atorvastatin (15mg/kg*d for one week starting at one, two, three, four and five weeks after BDL (T1-T5, while controls remained untreated. Hepatic fibrosis was analyzed by immunohistochemistry and hepatic hydroxyproline content. TGFβ levels were measured by RT-PCR. Proteolytic activity of MMP-2 was examined by zymography. Levels of degradation MMP driven type I, III, IV and VI collagen degradation (C1M, C3M, C4M and C6M and type III and IV collagen formation (PRO-C3 and P4NP7S markers were assessed by specific ELISAs in serum probes.ResultsSerum markers of ECM neo-epitopes reflected significantly the deposition of ECM in the liver and were able to distinguish between early (T1-T3 and severe fibrosis (T4-T5. Statin treatment to the fibrotic livers resulted in reduction of neo-epitope markers, especially when therapy was started in the stage of severe fibrosis (T4-T5. Furthermore, these markers correlated with hepatic expression of profibrotic cytokines TGFβ1 and TGFβ2. Formation markers of type III and IV collagen (PRO-C3 and P4NP7S and degradation markers C4M and C6M correlated significantly with MMP-2 activity in rats with severe fibrosis. ConclusionDetermination of ECM remodelling turnover markers in serum allowed a distinction between mild and severe fibrosis. With respect to statin therapy, the markers may serve as read-out for efficacy of anti-fibrotic treatment.

  3. Shortcut Access to Peptidosteroid Conjugates: Building Blocks for Solid-Phase Bile Acid Scaffold Decoration by Convergent Ligation

    Directory of Open Access Journals (Sweden)

    Sara Figaroli

    2011-12-01

    Full Text Available We present three versatile solid-supported scaffold building blocks based on the (deoxycholic acid framework and decorated with handles for further derivatization by modern ligation techniques such as click chemistry, Staudinger ligation or native chemical ligation. Straightforward procedures are presented for the synthesis and analysis of the steroid constructs. These building blocks offer a new, facile and shorter access route to bile acid-peptide conjugates on solid-phase with emphasis on heterodipodal conjugates with defined spatial arrangements. As such, we provide versatile new synthons to the toolbox for bile acid decoration.

  4. Characterization of the source distribution of particulate matter and nitrogen oxides in rural and urban areas; Charakterisierung der Quellverteilung von Feinstaub und Stickoxiden in laendlichem und staedtischem Gebiet

    Energy Technology Data Exchange (ETDEWEB)

    Urban, Susanna

    2010-07-01

    . It could be demonstrated that the total background is composed of quantifying fractions of the regional and the urban background. The difference of the current measuring signals and the regional background represents the maximum achievable release potential through traffic related activities for traffic dominated trace substances. Moreover, typical particulate size distributions and VOC-compositions of different contamination scenarios (urban, suburban and rural with biogenic contribution) could be determined. Adequate weather conditions approved the investigation of inversion layers of trace substances by the passing of a mountain when using the ''driving air-lab''. During the measurement campaign in Duesseldorf three characteristic measuring scenarios of a city, arterial streets, side streets and a tunnel, were distinguished. The correlation analysis showed a coemission of particles and nitrogen oxides. Furthermore, a total background concentration-field with street resolution of a residential area was created which reveals that the representativeness of a hypothetical measuring station only reaches a few 100 m. The multiregression analysis with source pattern of different engine systems in variable operating conditions demonstrated that the main contribution of the VOC-emissions derives from gasoline engines in cold start status. To determine the reaching range of an intense line source, measurements on and close to the highway in the area of Juelich were performed. By means of the crossing of a highway bridge the particle size concentrations demonstrate that the sphere of influence of a highway reaches several 100 m depending on the meteorological and orographic conditions. The gas chromatographic analysis and the following pattern analysis of mobile collected filters of a measuring route in the area of Juelich with motorway, highway, urban and rural road parts revealed a diesel soot contribution of more than 40% to total particulate matter

  5. N掺杂富含(001)晶面TiO2纳米片的制备及N掺杂浓度对可见光催化活性的影响%Synthesis, Characterization, and Nitrogen Concentration Depended Visible-Light Photoactivity of Nitrogen-Doped TiO2 Nanosheets with Dominant (001) Facets

    Institute of Scientific and Technical Information of China (English)

    王卫; 陆春华; 苏明星; 倪亚茹; 许仲梓

    2012-01-01

    采用水热法制备了富含(001)晶面的锐钛矿型TiO2纳米片,并通过改变热处理过程中NH3流速制备不同N掺杂浓度的TiO2纳米片.运用X射线衍射、场发射扫描电镜、高分辨率透射电子显微镜、紫外-可见漫反射光谱、X射线光电子能谱和荧光光谱对光催化剂进行了结构和性能表征,并以罗丹明B为目标降解物,考察了N掺杂浓度对TiO2纳米片可见光催化活性的影响.结果表明,NH3流速为40 ml/min时制备的N掺杂TiO2纳米片具有最低的光生电子-空穴复合速率,最高的·OH产生能力并表现出最高的光催化活性.同时,讨论了N掺杂浓度对TiO2纳米片可见光催化活性影响的机理.%Anatase TiO2 nanosheets with dominant (001) facets were prepared by a simple hydrothermal method.Nitrogen-doped TiO2 nanosheets (TiO2-N) with different nitrogen concentration were successfully synthesized by annealing TiO2 nanosheets in NH3 atmosphere with different NH3 flow rate at 400 ℃ for 3 h.The morphology,nanostructures,and properties of TiO2-N were characterized by X-ray diffraction,field emission scanning electron microscopy,high resolution transmission electron microscopy,ultraviolet-visible diffuse reflection spectroscopy,X-ray photoelectron spectroscopy,and photoluminescence.The effects of NH3 flow rate on the nanostructures,properties,and visible-light photoactivity in the degradation of rhodamine B (RhB) aqueous solution under visible light (λ > 400 nm) irradiation of the prepared photocatalysts were investigated.Among all the prepared photocatalysts including nitrogen modified P25 (Degussa),TiO2-N prepared with a NH3 flow rate of 40 ml/min gave the highest visible-light photoactivity because of the dominant (001) facets,visible light responsibility,the slowest photogenerated electron (e-) and hole (h+) pairs recombination rate,and the highest hydroxyl radicle (·OH) generation ability.Based on these experiments and analysis,the mechanisms of how

  6. Synthesis and Characterization of 5-Nitro-2-nitratomethyl-1,2,3,4-tetrazole: A High Nitrogen Energetic Compound with Good Oxygen Balance

    Directory of Open Access Journals (Sweden)

    Siping Pang

    2012-05-01

    Full Text Available The synthesis of 5-nitro-2-nitratomethyl-1,2,3,4-tetrazole (4 and its full characterization are given here. Compound 4 was synthesized through the nitration of 5-nitro-2-hydroxymethyl-tetrazole (3 with fuming nitric acid and acetic anhydride and its structure was characterized by MS, FT-IR, 1H-NMR and 13C-NMR techniques. The crystal structure of 4 was determined by X-ray single crystal diffraction analysis. The compound belongs to the orthorhombic system with space group Pna2(1, and its crystal parameters were a = 2.121(8 nm, b = 0.5281(19 nm, c = 0.6246(2 nm, Z = 4, V = 0.6995(4 nm3, Dc = 1.805 g/cm3, F(000 = 384, μ = 0.174 mm−1. A theoretical study of 4 has been performed, using quantum computational density functional theory (B3LYP methods with 6-31G* basis sets as implemented in the Gaussian 03 program suite. The obtained heat of formation (HOF for 4 was 228.07 kJ·mol−1, the detonation pressure (P values calculated for 4 was 37.92 GPa, the detonation velocity (D can reach 9260 m·s−1, and the oxygen balance was zero (Q, making 4 a competitive energetic compound.

  7. Denitrifying Characterizations from Inorganic Nitrogen-polluted Wastewater by Rhodopseudomonas palustris CQV97%沼泽红假单胞菌CQV97菌株对污染水体三氮去除特性研究

    Institute of Scientific and Technical Information of China (English)

    赵玥; 赵春贵; 陈龑; 杨素萍

    2012-01-01

    在不同污染程度模拟水体中,利用沼泽红假单胞菌CQV97,在厌氧光照条件下,研究了水体中氨氯、硝态氮和亚硝态氮含量、菌体生物量和水体pH的变化关系.随时间延长,CQV97菌株对氨氮、硝态氮或亚硝态氮去除量增大,生物量增加,水体pH升高;随氨氮浓度提高,生物量增加,氨氮低于33.2 mg/L能被完全去除,最大去除量达84.2 mg/L,水体pH维持在9.2~9.4;随硝态氮浓度的升高,菌体生物量降低,浓度低于216.96 mg/L能被完全去除,pH维持在9.1~9.3.随亚硝态氮浓度增加,菌体生长延滞期延长,生物量和pH升高幅度降低,浓度低于128.2mg/L能被完全去除.结果表明,CQV97菌株对氨氮、硝氮和亚硝氮具有良好的去除能力.%The relationship among removal amount and removal rate of ammonia nitrogen, nitrate nitrogen and nitrite nitrogen,biomass as well as pH change in simulation wastewater polluted by different nitrogen compounds with Rhodopseudomonas palustris CQV97 were investigated under anaerobically in the light. The results showed that strain CQV 97 had better capability of ammonia nitrogen removal. The removal a-mount and removal rate of ammonia nitrogen, biomass and pH increased during 10 d. With the increasing ammonia nitrogen concentration, the removal amount of ammonia nitrogen and biomass enhanced, pH reached at 9. 2~9. 4,but the apparent removal rate of ammonia nitrogen reduced. Less than 33. 2 mg/L ammonia nitrogen could be completely removed. The maximal removal amount of ammonia nitrogen reached 84.2 mg/L. In the nitrate nitrogen-containing polluted wastewater, strain CQV97 could utilize, transform and rapidly and effectively remove nitrate nitrogen, cell growth and pH gradually increased while the nitrate nitrogen was constantly removed. With increasing nitrate nitrogen concentration, the biomass decreased, pH maintained at 9. 1~9. 3. The nitrate nitrogen could be removed completely and the maximal removal

  8. Sortase-mediated ligation of PsaE-modified photosystem I from Synechocystis sp. PCC 6803 to a conductive surface for enhanced photocurrent production on a gold electrode.

    Science.gov (United States)

    Le, Rosemary K; Raeeszadeh-Sarmazdeh, Maryam; Boder, Eric T; Frymier, Paul D

    2015-01-27

    Sortase-mediated ligation was used to attach the photosystem I (PSI) complex from Synechocystis sp. PCC 6803 in a preferential orientation to enhance photoinduced electron flow to a conductive gold surface. Ideally, this method can result in a uniform monolayer of protein, covalently bound unidirectionally to the electrode surface. The exposed C-termini of the psaE subunits of the PSI trimer were targeted to contain an LPETG-sortase recognition sequence to increase noncompeting electron transfer by uniformly orienting the PSI stromal side proximal to the surface. Surface characterization with atomic force microscopy suggested that monolayer formation and optimal surface coverage occurred when the gold surfaces were incubated with peptide at 100 to 500 μM concentrations. When photochronoamperometry with potassium ferrocyanide and ferricyanide as redox mediators was used, photocurrents in the range of 100 to 200 nA/cm(2) were produced, which is an improvement over other attachment techniques for photosystem monolayers that produce approximately 100 nA/cm(2) or less. This work demonstrated that sortase-mediated ligation aided in the control of PSI orientation on modified gold surfaces with a distribution of 94% stromal side proximal and 6% lumenal side proximal to the surface for current-producing PSI.

  9. Microscope-assisted endoscopic interlaminar ligation of spinal arteriovenous fistulas: technical note.

    Science.gov (United States)

    Wang, Chen; Chen, Chien-Min; Shen, Fang; Fang, Xiao-Dong; Ying, Guang-Yu; Ren, Yu-Cheng; Yu, Dan-Feng; Zhu, Liang-Liang; Zhu, Yong-Jian; Zhang, Jian-Min

    2016-09-01

    Spinal dural arteriovenous fistulas (SDAVFs) are the most common type of spinal arteriovenous malformations, and microsurgical ligation is the treatment modality most frequently used for these lesions. Developments in endoscopic techniques have made endoscopy an even less invasive alternative to routine microsurgical approaches in spine surgery, but endoscopic management of SDAVF or other intradural spinal lesions has not been reported to date. The authors describe the use of a microscope-assisted endoscopic interlaminar approach for the ligation of the proximal draining vein of an L-1 SDAVF in a 58-year-old man. A complete cure was confirmed by postoperative angiography. The postoperative course was uneventful, and short-term follow-up showed improvements in the patient's neurological function. The authors conclude that the endoscopic interlaminar approach with microscope assistance is a safe, minimally invasive, innovative technique for the surgical management of SDAVFs in selected patients.

  10. Ultrasensitive monitoring of ribozyme cleavage product using molecular-beacon-ligation system

    Institute of Scientific and Technical Information of China (English)

    MENG XiangXian; TANG ZhiWen; WANG KeMin; TAN WeiHong; YANG XiaoHai; LI Jun; GUO QiuPing

    2007-01-01

    This paper reports a new approach to detect ribozyme cleavage product based on the molecular- beacon-ligation system. The molecular beacon, designed in such a way that one-half of its loop is complementary to ribozyme cleavage product, is used to monitor ligation process of RNA/DNA complex in a homogeneous solution and to convert directly cleavage product information into fluorescence signal. The method need not label ribozyme and ribozyme substrate, which is fast, simple and ultrasensitive for detection of cleavage product. Detection limit of the assay is 0.05 nmol/L. The cleavage product of hammerhead ribozyme against hepatitis C virus RNA (HCV-RNA) was detected perfectly based on this assay. Owing to its ultrasensitivity, excellent specificity, convenience and fidelity, this method might hold out great promise in ribozyme reaction and ribozyme gene therapy.

  11. Generation of an affinity column for antibody purification by intein-mediated protein ligation.

    Science.gov (United States)

    Sun, Luo; Ghosh, Inca; Xu, Ming-Qun

    2003-11-01

    Coupling an antigenic peptide to a solid support is a crucial step in the affinity purification of a peptide-specific antibody. Conventional methods for generating reactive agarose, cellulose or other matrices for peptide conjugation are laborious and can result in a significant amount of chemical waste. In this report, we present a novel method for the facile production of a peptide affinity column by employing intein-mediated protein ligation (IPL) in conjunction with chitin affinity chromatography. A reactive thioester was generated at the C-terminal of the chitin binding domain (CBD) from the chitinase A1 of Bacillus circulans WL-2 by thiol-induced cleavage of the peptide bond between the CBD and a modified intein. Peptide epitopes possessing an N-terminal cysteine were ligated to the chitin bound CBD tag. We demonstrate that the resulting peptide columns permit the highly specific and efficient affinity purification of antibodies from animal sera.

  12. Characterization of the source distribution of particulate matter and nitrogen oxides in rural and urban areas; Charakterisierung der Quellverteilung von Feinstaub und Stickoxiden in laendlichem und staedtischem Gebiet

    Energy Technology Data Exchange (ETDEWEB)

    Urban, Susanna

    2010-07-01

    . It could be demonstrated that the total background is composed of quantifying fractions of the regional and the urban background. The difference of the current measuring signals and the regional background represents the maximum achievable release potential through traffic related activities for traffic dominated trace substances. Moreover, typical particulate size distributions and VOC-compositions of different contamination scenarios (urban, suburban and rural with biogenic contribution) could be determined. Adequate weather conditions approved the investigation of inversion layers of trace substances by the passing of a mountain when using the ''driving air-lab''. During the measurement campaign in Duesseldorf three characteristic measuring scenarios of a city, arterial streets, side streets and a tunnel, were distinguished. The correlation analysis showed a coemission of particles and nitrogen oxides. Furthermore, a total background concentration-field with street resolution of a residential area was created which reveals that the representativeness of a hypothetical measuring station only reaches a few 100 m. The multiregression analysis with source pattern of different engine systems in variable operating conditions demonstrated that the main contribution of the VOC-emissions derives from gasoline engines in cold start status. To determine the reaching range of an intense line source, measurements on and close to the highway in the area of Juelich were performed. By means of the crossing of a highway bridge the particle size concentrations demonstrate that the sphere of influence of a highway reaches several 100 m depending on the meteorological and orographic conditions. The gas chromatographic analysis and the following pattern analysis of mobile collected filters of a measuring route in the area of Juelich with motorway, highway, urban and rural road parts revealed a diesel soot contribution of more than 40% to total particulate matter

  13. Synthesis, characterization, cytotoxicity and antimicrobial studies on bis(N-furfuryl-N-(2-phenylethyl)dithiocarbamato-S,S')zinc(II) and its nitrogen donor adducts.

    Science.gov (United States)

    Rani, Palanisamy Jamuna; Thirumaran, Subbiah

    2013-04-01

    [Zn(fpedtc)2] (1), [Zn(fpedtc)2(py)] (2), [Zn(fpedtc)2(1,10-phen)] (3) and [Zn(fpedtc)2(2,2'-bipy)] (4) (where fpedtc = N-furfuryl-N-(2-phenylethyl)dithiocarbamate, py = pyridine, 1,10-phen = 1,10-phenanthroline and 2,2'-bipy = 2,2'-bipyridine) were synthesized. Characterization of the complexes were achieved by IR and NMR ((1)H and (13)C) spectra and in addition, for 2 and 3, by X-ray crystallography. Single crystal X-ray structural analysis of 2 and 3 showed that complex 2 is almost half way between trigonal bipyramidal and square pyramidal and complex 3 has a distorted octahedral geometry. Zn-N distances in 2 is shorter than that found in a six coordinate complex 3 due to the change in coordination number. These complexes were also screened for in vitro antibacterial and antifungal activities and significant activities have been found. In vitro cytotoxic activity of all the synthesized complexes was evaluated on HeLa cell line. Complex 1 exhibits maximum inhibitory effect at a concentration of 40 μg mL(-1) on HeLa cell line.

  14. Sequential ultrasonic extraction of a Chinese coal and characterization of nitrogen-containing compounds in the extracts using high-performance liquid chromatography with mass spectrometry.

    Science.gov (United States)

    Xia, Jun-Liu; Fan, Xing; You, Chun-Yan; Wei, Xian-Yong; Zhao, Yun-Peng; Cao, Jing-Pei

    2016-07-01

    Dongming lignite was sequentially extracted with petroleum ether, carbon disulfide, methanol, acetone, and isometric carbon disulfide/acetone mixed solvent at room temperature to afford extracts 1-5, respectively. High-performance liquid chromatography coupled with electrospray ionization time-of-flight mass spectrometry was used to separate and characterize heteroatomic species in the extracts at molecular level. Molecular mass of compounds in the extracts is mainly distributed from 300 to 800 u, and the relative abundance of compounds with molecular mass over 800 u in the carbon disulfide extract is 135 times of that in the petroleum ether extract. The acetone extract has the highest relative abundance for organonitrogen compounds. Double bond equivalence numbers of detected species indicate that most of the organonitrogen compounds contain N-heterocyclic aromatic rings, including pyridine, quinoline and pyrrole. Some organonitrogen isomers in Dongming lignite were separated and identified by high-performance liquid chromatography coupled with electrospray ionization time-of-flight mass spectrometry, and the corresponding structural information was proposed.

  15. Nitrogen control of chloroplast differentiation

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, G.W.

    1992-07-01

    This project is directed toward understanding how the availability of nitrogen affects the accumulation of chloroplast pigments and proteins functioning in energy transduction and carbon metabolism. Molecular analyses performed with Chlamydomonas reinhardtii grown in a continuous culture system such that ammonium concentration is maintained at a low steady-state concentration so as to limit cell division. As compared to chloroplasts from cells of non-limiting nitrogen provisions, chloroplasts of N-limited cells are profoundly chlorophyll-deficient but still assimilate carbon for deposition of as starch and as storage lipids. Chlorophyll deficiency arises by limiting accumulation of appropriate nuclear-encoded mRNAs of and by depressed rates of translation of chloroplast mRNAs for apoproteins of reaction centers. Chloroplast translational effects can be partially ascribed to diminished rates of chlorophyll biosynthesis in N-limited cells, but pigment levels are not determinants for expression of the nuclear light-harvesting protein genes. Consequently, other signals that are responsive to nitrogen availability mediate transcriptional or post-transcriptional processes for accumulation of the mRNAs for LHC apoproteins and other mRNAs whose abundance is dependent upon high nitrogen levels. Conversely, limited nitrogen availability promotes accumulation of other proteins involved in carbon metabolism and oxidative electron transport in chloroplasts. Hence, thylakoids of N-limited cells exhibit enhanced chlororespiratory activities wherein oxygen serves as the electron acceptor in a pathway that involves plastoquinone and other electron carrier proteins that remain to be thoroughly characterized. Ongoing and future studies are also outlined.

  16. Zeolite ZSM5 catalysts for abatement of nitrogen oxide

    Energy Technology Data Exchange (ETDEWEB)

    Ganemi, Bager

    1999-07-01

    Airborne pollutants from the combustion of fossil fuels are a global problem. Emission of nitrogen oxides (NO{sub x}) is increasing with the worldwide increase in the use of energy. Atmospheric and photochemical reactions link nitrogen oxides to hydrocarbons and tropospheric ozone. The emission of NO{sub x} has to be tackled urgently in order to limit the harmful effects of anthropogenic activity on the environment. The subject of this thesis is catalytic nitrogen oxide abatement through direct decomposition and reduction by methane over ion-exchanged zeolite ZSM5. The work covers catalytic conversion and surface intermediates, including correlations with the level of exchanged Cu{sup 2+} cations and Ni{sup 2+} or Pd{sup 2+} co-cations. Special attention is given to the aluminium content of the support and changes in structural parameters. It was found that NO{sub x} conversion over cation-exchanged ZSM5 is strongly influenced by the ion-exchange procedure and by the above material parameters. Characterization of Cu-ZSM5 reveals that approximately two molecules of water per Cu{sup 2+} ion desorb at temperatures between 150 and 350 Deg C, in addition to the conventional dehydration at lower temperatures. The desorbed water comes from the decomposition of Cu(OH){sub 2}. Decomposition of hydroxylated copper ions results in the formation Of Cu{sup 2+}-O-Cu{sup 2+} dimers, which are suggested to be the active sites for catalytic decomposition of NO. Acid sites are important for the dispersion of copper ions on the catalyst surface. Acid sites are also important for the interaction between copper species and the zeolite. Increased acidity leads to a stronger interaction between the exchanged cation and the framework, i.e. the exchanged cations become more resistant to mobility. The stronger bond between the exchanged cations and lattice oxygen also prevents dealumination of the catalyst and decreases the thermal expansion at higher temperatures. The temperature of

  17. EXPRESSED PROTEIN LIGATION. A NEW TOOL FOR THE BIOSYNTHESIS OF CYCLIC POLYPEPTIDES

    Energy Technology Data Exchange (ETDEWEB)

    Kimura, R; Camarero, J A

    2004-11-11

    The present paper reviews the use of expressed protein ligation for the biosynthesis of backbone cyclic polypeptides. This general method allows the in vivo and in vitro biosynthesis of cyclic polypeptides using recombinant DNA expression techniques. Biosynthetic access to backbone cyclic peptides opens the possibility to generate cell-based combinatorial libraries that can be screened inside living cells for their ability to attenuate or inhibit cellular processes.

  18. Are self-ligating brackets related to less formation of Streptococcus mutans colonies? A systematic review

    Directory of Open Access Journals (Sweden)

    Leonard Euler Andrade Gomes do Nascimento

    2014-01-01

    Full Text Available OBJECTIVE: To verify, by means of a systematic review, whether the design of brackets (conventional or self-ligating influences adhesion and formation of Streptococcus mutans colonies. METHODS: Search strategy: four databases (Cochrane Central Register of Controlled Trials, Ovid ALL EMB Reviews, PubMed and BIREME were selected to search relevant articles covering the period from January 1965 to December 2012. Selection Criteria: in first consensus by reading the title and abstract. The full text was obtained from publications that met the inclusion criteria. Data collection and analysis: Two reviewers independently extracted data using the keywords: conventional, self-ligating, biofilm, Streptococcus mutans, and systematic review; and independently evaluated the quality of the studies. In case of divergence, the technique of consensus was adopted. RESULTS: The search strategy resulted in 1,401 articles. The classification of scientific relevance revealed the high quality of the 6 eligible articles of which outcomes were not unanimous in reporting not only the influence of the design of the brackets (conventional or self-ligating over adhesion and formation of colonies of Streptococcus mutans, but also that other factors such as the quality of the bracket type, the level of individual oral hygiene, bonding and age may have greater influence. Statistical analysis was not feasible because of the heterogeneous methodological design. CONCLUSIONS: Within the limitations of this study, it was concluded that there is no evidence for a possible influence of the design of the brackets (conventional or self-ligating over colony formation and adhesion of Streptococcus mutans.

  19. An enhanced method for sequence walking and paralog mining: TOPO® Vector-Ligation PCR

    Directory of Open Access Journals (Sweden)

    Davis Thomas M

    2010-03-01

    Full Text Available Abstract Background Although technological advances allow for the economical acquisition of whole genome sequences, many organisms' genomes remain unsequenced, and fully sequenced genomes may contain gaps. Researchers reliant upon partial genomic or heterologous sequence information require methods for obtaining unknown sequences from loci of interest. Various PCR based techniques are available for sequence walking - i.e., the acquisition of unknown DNA sequence adjacent to known sequence. Many such methods require rigid, elaborate protocols and/or impose narrowly confined options in the choice of restriction enzymes for necessary genomic digests. We describe a new method, TOPO® Vector-Ligation PCR (or TVL-PCR that innovatively integrates available tools and familiar concepts to offer advantages as a means of both targeted sequence walking and paralog mining. Findings TVL-PCR exploits the ligation efficiency of the pCR®4-TOPO® (Invitrogen, Carlsbad, California vector system to capture fragments of unknown sequence by creating chimeric molecules containing defined priming sites at both ends. Initially, restriction enzyme-digested genomic DNA is end-repaired to create 3' adenosine overhangs and is then ligated to pCR4-TOPO vectors. The ligation product pool is used directly as a template for nested PCR, using specific primers to target orthologous sequences, or degenerate primers to enable capture of paralogous gene family members. We demonstrated the efficacy of this method by capturing entire coding and partial promoter sequences of several strawberry Superman-like genes. Conclusions TVL-PCR is a convenient and efficient method for DNA sequence walking and paralog mining that is applicable to any organism for which relevant DNA sequence is available as a basis for primer design.

  20. Superficial Dorsal Vein Injury/Thrombosis Presenting as False Penile Fracture Requiring Dorsal Venous Ligation

    OpenAIRE

    Arash Rafiei, MD; Tariq S. Hakky, MD; Daniel Martinez, MD; Justin Parker, MD; Rafael Carrion, MD

    2014-01-01

    Introduction: Conditions mimicking penile fracture are extremely rare and have been seldom described. Aim: To describe a patient with false penile fracture who presented with superficial dorsal vein injury/thrombosis managed with ligation. Methods: A 33‐year‐old male presented with penile swelling and ecchymosis after intercourse. A penile ultrasound demonstrated a thrombosed superficial dorsal vein but also questionable fracture of the tunica albuginea. As the thrombus was expanding, h...

  1. Clinical and psychological repercussions of videolaparoscopic tubal ligation: observational, single cohort, retrospective study

    Directory of Open Access Journals (Sweden)

    Daniel Spadoto Dias

    Full Text Available CONTEXT AND OBJECTIVE: Tubal ligation is one of the most commonly used contraceptive methods worldwide. Since the controversy over the potential effects of tubal sterilization still continues, this study aimed to evaluate the clinical and psychological repercussions of videolaparoscopic tubal ligation.DESIGN AND SETTING: Observational, single cohort, retrospective study, conducted in a tertiary public hospital.METHODS: A questionnaire was applied to 130 women aged 21-46 years who underwent videolaparoscopic tubal ligation by means of tubal ring insertion or bipolar electrocoagulation and sectioning, between January 1999 and December 2007. Menstrual cycle interval, intensity and duration of bleeding, premenstrual symptoms, dysmenorrhea, dyspareunia, noncyclic pelvic pain and degree of sexual satisfaction were assessed in this questionnaire. Each woman served as her own control, and comparisons were made between before and after the surgical procedure and between the two techniques used.RESULTS: The clinical and psychological repercussions were significant, with increases in bleeding (P = 0.001, premenstrual symptoms (P < 0.001, dysmenorrhea (P = 0.019 and noncyclic pelvic pain (P = 0.001; and reductions in the number of sexual intercourse occurrences per week (P = 0.001 and in libido (P = 0.001. Women aged ≤ 35 years at the time of sterilization were more likely to develop menstrual abnormalities. The bipolar electrocoagulation method showed greater clinical and psychological repercussions.CONCLUSION: Regardless of the technique used, videolaparoscopic tubal ligation had repercussions consisting of increased menstrual flow and premenstrual symptoms, especially in women aged ≤ 35 years, and also had a negative influence on sexual activity.

  2. Banding ligation versus beta-blockers for primary prevention in oesophageal varices in adults

    DEFF Research Database (Denmark)

    Gluud, Lise Lotte; Krag, Aleksander

    2012-01-01

    Non-selective beta-blockers are used as a first-line treatment for primary prevention in patients with medium- to high-risk oesophageal varices. The effect of non-selective beta-blockers on mortality is debated and many patients experience adverse events. Trials on banding ligation versus non......-selective beta-blockers for patients with oesophageal varices and no history of bleeding have reached equivocal results....

  3. Venous Ligation: A Novel Strategy for Glans Enhancement in Penile Prosthesis Implantation

    OpenAIRE

    Geng-Long Hsu; Hill, James W.; Cheng-Hsing Hsieh; Shih-Ping Liu; Chih-Yuan Hsu

    2014-01-01

    Although penile implantation remains a final solution for patients with refractory impotence, undesirable postoperative effects, including penile size reduction and cold sensation of the glans penis, remain problematic. We report results of a surgical method designed to avoid these problems. From 2003 to 2013, 35 consecutive patients received a malleable penile implant. Of these, 15 men (the enhancing group) were also treated with venous ligation of the retrocoronal venous plexus, deep dorsal...

  4. Transversal changes in dental arches from non-extraction treatment with self ligating brackets

    OpenAIRE

    Liliana Avila Maltagliati; Yasushi Inoue Myiahira; Liana Fattori; Leopoldino Capelozza Filho; Mauricio Cardoso

    2013-01-01

    OBJECTIVE: The present study aimed at analyzing, with the use of dental casts, the transverse changes of the upper and lower dental arches, after non-extraction orthodontic treatment, with self-ligating brackets. METHODS: The sample comprised 29 patients, all presenting Class I malocclusion with upper and lower crowding of at least 4 mm and treated only with a fixed appliance, without stripping, extraction or distalization. The dental casts were obtained before and after leveling with 0.019 x...

  5. Diamino-ligated platinum(II) and platinum(IV) phenoxide complexes; syntheses and crystal structures

    NARCIS (Netherlands)

    Koten, G. van; Kapteijn, G.M.; Meijer, M.D.; Grove, D.M.; Veldman, N.; Spek, A.L.

    1997-01-01

    The reaction of the diamino-ligated dimethylplatinum(II) complex [Pt(Me){2}(bpy)] (bpy=2, 2'-bipyridyl) with phenol affords the new complex [Pt(Me)(OPh)(bpy)] (1). The X-ray crystal structure of square-planar 1 is reported: orthorhombic, space group P2{1}2{1}2{1} (No. 19), a = 9.1625(12), b = 12.392

  6. Entropy score, patent ductus arteriosus (PDA), and cardiopulmonary bypass (CPB): ligation of PDA on CPB can compromise cerebral blood flow.

    Science.gov (United States)

    Neema, Praveen Kumar; Dharan, Baiju S; Singha, Subrata Kumar; Sethuraman, Manikandan; Rathod, Ramesh Chandra

    2011-01-01

    A patent ductus arteriosus (PDA) is often present in patients undergoing correction of congenital heart disease. It is well appreciated that during cardiopulmonary bypass (CPB), a PDA steals arterial inflow into pulmonary circulation, and may lead to systemic hypoperfusion, excessive pulmonary blood flow (PBF) and distention of the left heart. Therefore, PDA is preferably ligated before initiation of CPB. We describe acute decreases of arterial blood pressure and entropy score with the initiation of CPB and immediate increase in entropy score following the PDA ligation in a child undergoing intracardiac repair of ventricular septal defect and right ventricular infundibular stenosis. The observation strongly indicates that a PDA steals arterial inflow into pulmonary circulation and if the PDA is dissected and ligated on CPB or its ligation on CPB is delayed the cerebral perfusion is potentially compromised.

  7. Self-ligating versus Invisalign: analysis of dento-alveolar effects

    Science.gov (United States)

    Pavoni, Chiara; Lione, Roberta; Laganà, Giuseppina; Cozza, Paola

    2011-01-01

    Summary Aim The aim of this study was to evaluate the changes in the transverse dimension and the perimeter of the maxillary arch produced by low friction self-ligating brackets TIME 3 compared to the Invisalign technique. Materials and methods Both the self-ligating sample and the Invisalign group were composed of 20 subjects, evaluated at the beginning (T0) and at the completion of therapy (T1). All subjects presented a Class I malocclusion with mild crowding in a permanent dentition, without craniofacial anomalies, missing teeth or a history of orthodontic treatment. Dento-alveolar measurements were made on the maxillary dental casts at T0 and T1. Significant differences between the treated groups were assessed with Independent Samples t test (pInvisalign group were recorded for CWC, FPWF, FPWL, SPWF, SPWL, and AP measurements. No significant changes were found for CWL, MWF, MWL, and AD values. There was not a statistically significant difference between the treatment durations of the groups: 1.8 years for both patients. These data suggest that Invisalign treatment cannot be somewhat faster than fixed appliances. Moreover the final occlusion might not be as ideal. Conclusions The low fiction self-ligating system produced statistically significant different outcomes in the transverse dento-alveolar width and the perimeter of the maxillary arch during treatment when compared to Invisalign tecnique. PMID:22238719

  8. External root resorption with the self-ligating Damon system—a retrospective study

    Directory of Open Access Journals (Sweden)

    Roberta Heiffig Handem

    2016-07-01

    Full Text Available Abstract Background The aim of this study was to compare the degree of external apical root resorption (EARR in patients treated with self-ligating Damon appliances and with conventional preadjusted appliances. Methods The sample comprised 52 patients, divided into two groups. Group 1 consisted of 25 patients treated with self-ligating Damon appliances, with an initial age of 16.04 years, final age of 18.06 years, and treatment time of 2.02 years. Group 2 consisted of 27 patients, treated with conventional preadjusted appliances, with an initial age of 16.77 years, final age of 18.47 years and treatment time of 1.70 years. The groups were matched regarding the initial and final ages, treatment time, type of malocclusion, and treatment protocol without extractions. Root resorption was evaluated on periapical radiographs of the maxillary and mandibular incisors at the end of orthodontic treatment with the scores of Levander and Malmgren. Intergroup comparisons of root resorption were performed with Mann-Whitney tests. Results No significant difference in the degree of root resorption between the two groups was found. Conclusions Similar degrees of resorption can be expected after non-extraction treatment with Damon self-ligating or conventional preadjusted appliances.

  9. Experiments to optimize enzyme substitution therapy in pancreatic duct-ligated pigs.

    Science.gov (United States)

    Kammlott, E; Karthoff, J; Stemme, K; Gregory, P; Kamphues, J

    2005-01-01

    Ligation of the pancreatic duct in pigs leads to severe maldigestion and malabsorption of crude nutrients. Supplementation with 24 capsules of Creon (Solvay Pharmaceuticals GmbH, Hannover, Germany) per meal led to an increased digestibility of crude nutrients. With regard to optimization of the treatment of EPI no essential improvements can be achieved by adding omeprazol or lecithin to the diet. In pancreatic duct-ligated pigs the isolated addition of omeprazol led to an increase of the pre-caecal digestibility of crude fat and organic matter. With additional enzyme substitution, the application of omeprazol did not result in an improved fat digestibility. Isolated addition of lecithin to the diet resulted in a reduced total digestibility of crude fat. Offering the diet twice a day and using a higher frequency of enzyme applications (four or six instead of only two applications) had no effects on the digestibilty of crude fat or organic matter. According to the observations in pancreatic duct-ligated pigs, the addition of missing enzymes to the diet led to the best treatment results in EPI. Administration of omeprazol or a higher feeding frequency as well as the application of enzymes in small proportion of the whole meal or dosages given consecutively over the day showed no advantages. Furthermore, the present study suggests that the addition of lecithin cannot be recommended in EPI, when given diets with butter as the predominant fat source as in human dietetics.

  10. Evaluation of force released by deflection of orthodontic wires in conventional and self-ligating brackets

    Directory of Open Access Journals (Sweden)

    Rodrigo Hitoshi Higa

    Full Text Available ABSTRACT Introduction: The aim of the study was to evaluate deflection forces of rectangular orthodontic wires in conventional (MorelliTM, active (In-Ovation RTM and passive (Damon 3MXTM self-ligating brackets. Material and Methods: Two brands of stainless steel and nickel-titanium (NiTi wires (MorelliTM and GACTM, in addition to OrmcoTM copper-nickel-titanium wires were used. Specimens were assembled in a clinical simulation device especially designed for this study and tested in an Instron universal testing machine. For the testing procedures, an acrylic structure representative of the maxillary right central incisor was lingually moved in activations of 0 to 1 mm, with readings of the force released by deflection in unloading of 0.5, 0.8 and 1 mm at a constant speed of 2 mm/min. Inter-bracket forces with stainless steel, NiTi and CuNiTi were individually compared by two-way ANOVA, followed by Tukey’s tests. Results: Results showed that there were lower forces in conventional brackets, followed by active and passive self-ligating brackets. Within the brands, only for NiTi wires, the MorelliTM brand presented higher forces than GACTM wires. Conclusions: Bracket systems provide different degrees of deflection force, with self-ligating brackets showing the highest forces.

  11. Usefulness of ligation-mediated PCR genotyping in tracking outbreak-associated Mycobacterium tuberculosis strains.

    Science.gov (United States)

    Mardassi, H; Namouchi, A; Karbouli, A; Khabouchi, N; Haltiti, R; Zarrouk, M; Mhennii, B; Kaabi, S

    2005-01-01

    With the emergence of a multidrug resistant tuberculosis (MDR-TB) outbreak, the availability of a rapid typing method to carry out a nationwide prospective survey for the tracking of newly emerging MDR-TB foci became a priority. For this purpose, we have applied the IS6110 PCR-based genotyping assay, namely, LM-PCR (ligation-mediated PCR). The latter relies on ligation of a synthetic oligonucleotide priming site to a restriction site flanking IS6110. Sequences between the IS element and the restriction site are then amplified using an IS6110 specific outward primer and an oligonucleotide specific to the ligated priming site. Although it was found slightly less discriminative than the standard IS6110 restriction fragment length polymorphism analysis (IS6110 RFLP), LM-PCR allowed for the rapid and prospective identification of new outbreak-related cases within a large pool of circulating M. tuberculosis isolates. In comparison to IS6110 RFLP LM-PCR was found simple enough to justify its implementation in laboratories involved in MDR-TB surveillance at a nationwide scale.

  12. Antioxidant Effect of Sepia Ink Extract on Extrahepatic Cholestasis Induced by Bile Duct Ligation in Rats

    Institute of Scientific and Technical Information of China (English)

    Hanan Saleh; Amel M Soliman; Ayman S Mohamed; Mohamed-Assem S Marie

    2015-01-01

    Objective The aim of our study was to assess the complications of hepatic fibrosis associated with bile duct ligation and the potential curative role of sepia ink extract in hepatic damage induced by bile duct ligation. Methods Rattus norvegicus rats were divided into 3 groups: Sham-operated group, model rats that underwent common bile duct ligation (BDL), and BDL rats treated orally with sepia ink extract (200 mg/kg body weight) for 7, 14, and 28 d after BDL. Results There was a significant reduction in hepatic enzymes, ALP, GGT, bilirubin levels, and oxidative stress in the BDL group after treatment with sepia ink extract. Collagen deposition reduced after sepia ink extract treatment as compared to BDL groups, suggesting that the liver was repaired. Histopathological examination of liver treated with sepia ink extract showed moderate degeneration in the hepatic architecture and mild degeneration in hepatocytes as compared to BDL groups. Conclusion Sepia ink extract provides a curative effect and an antioxidant capacity on BDL rats and could ameliorate the complications of liver cholestasis.

  13. Safety and effectiveness of total splenic vessel ligations in paediatric patients with splenomegaly

    Directory of Open Access Journals (Sweden)

    Chen Zhen

    2016-01-01

    Full Text Available Backgrounds: Splenomegaly may contribute to hypersplenism and can result in thrombocytopenia. Many approaches are used to treat splenomegaly; however, the current management of splenomegaly has intrinsic limitations or disadvantages. Now, we initiate a new approach, that of total splenic vessel (artery and vein ligations (TSVLs in paediatric patients with splenomegaly. The purpose of our study is to evaluate the results obtained with TVSLs procedure for paediatric patients. Patients and Methods: Seventeen paediatric patients with splenomegaly were screened for enrolment into this retrospective analysis. Procedure: We identified and dissociated the splenic vessel. Next, we ligated the splenic artery and we used clips to ligate the vein distally and proximally. Result: The mean [standard deviation (SD] splenic infarction rate of a total of 17 patients was 77.5 (5.1% in 6 months after operation. After TSVL, the mean count of platelet (PLT and white blood cell (WBC increased significantly and reached a steady state in the third month. Both the PLT and WBC had a significance higher than pre-TSVL in a 1-year follow-up. Conclusion: Based on the evidence, we make cautious conclusions that TSVLs are a safe and effective method in the treatment of paediatric patients with splenomegaly, achieving a satisfactory long-term haematological response and benefit.

  14. The exonuclease activity of DNA polymerase γ is required for ligation during mitochondrial DNA replication

    Science.gov (United States)

    Macao, Bertil; Uhler, Jay P.; Siibak, Triinu; Zhu, Xuefeng; Shi, Yonghong; Sheng, Wenwen; Olsson, Monica; Stewart, James B.; Gustafsson, Claes M.; Falkenberg, Maria

    2015-01-01

    Mitochondrial DNA (mtDNA) polymerase γ (POLγ) harbours a 3′–5′ exonuclease proofreading activity. Here we demonstrate that this activity is required for the creation of ligatable ends during mtDNA replication. Exonuclease-deficient POLγ fails to pause on reaching a downstream 5′-end. Instead, the enzyme continues to polymerize into double-stranded DNA, creating an unligatable 5′-flap. Disease-associated mutations can both increase and decrease exonuclease activity and consequently impair DNA ligation. In mice, inactivation of the exonuclease activity causes an increase in mtDNA mutations and premature ageing phenotypes. These mutator mice also contain high levels of truncated, linear fragments of mtDNA. We demonstrate that the formation of these fragments is due to impaired ligation, causing nicks near the origin of heavy-strand DNA replication. In the subsequent round of replication, the nicks lead to double-strand breaks and linear fragment formation. PMID:26095671

  15. Evaluation of force released by deflection of orthodontic wires in conventional and self-ligating brackets

    Science.gov (United States)

    Higa, Rodrigo Hitoshi; Semenara, Nayara Thiago; Henriques, José Fernando Castanha; Janson, Guilherme; Sathler, Renata; Fernandes, Thais Maria Freire

    2016-01-01

    ABSTRACT Introduction: The aim of the study was to evaluate deflection forces of rectangular orthodontic wires in conventional (MorelliTM), active (In-Ovation RTM) and passive (Damon 3MXTM) self-ligating brackets. Material and Methods: Two brands of stainless steel and nickel-titanium (NiTi) wires (MorelliTM and GACTM), in addition to OrmcoTM copper-nickel-titanium wires were used. Specimens were assembled in a clinical simulation device especially designed for this study and tested in an Instron universal testing machine. For the testing procedures, an acrylic structure representative of the maxillary right central incisor was lingually moved in activations of 0 to 1 mm, with readings of the force released by deflection in unloading of 0.5, 0.8 and 1 mm at a constant speed of 2 mm/min. Inter-bracket forces with stainless steel, NiTi and CuNiTi were individually compared by two-way ANOVA, followed by Tukey’s tests. Results: Results showed that there were lower forces in conventional brackets, followed by active and passive self-ligating brackets. Within the brands, only for NiTi wires, the MorelliTM brand presented higher forces than GACTM wires. Conclusions: Bracket systems provide different degrees of deflection force, with self-ligating brackets showing the highest forces. PMID:28125144

  16. Synthesizing and modifying peptides for chemoselective ligation and assembly into quantum dot-peptide bioconjugates.

    Science.gov (United States)

    Algar, W Russ; Blanco-Canosa, Juan B; Manthe, Rachel L; Susumu, Kimihiro; Stewart, Michael H; Dawson, Philip E; Medintz, Igor L

    2013-01-01

    Quantum dots (QDs) are well-established as photoluminescent nanoparticle probes for in vitro or in vivo imaging, sensing, and even drug delivery. A critical component of this research is the need to reliably conjugate peptides, proteins, oligonucleotides, and other biomolecules to QDs in a controlled manner. In this chapter, we describe the conjugation of peptides to CdSe/ZnS QDs using a combination of polyhistidine self-assembly and hydrazone ligation. The former is a high-affinity interaction with the inorganic surface of the QD; the latter is a highly efficient and chemoselective reaction that occurs between 4-formylbenzoyl (4FB) and 2-hydrazinonicotinoyl (HYNIC) moieties. Two methods are presented for modifying peptides with these functional groups: (1) solid phase peptide synthesis; and (2) solution phase modification of pre-synthesized, commercial peptides. We further describe the aniline-catalyzed ligation of 4FB- and HYNIC-modified peptides, in the presence of a fluorescent label on the latter peptide, as well as subsequent assembly of the ligated peptide to water-soluble QDs. Many technical elements of these protocols can be extended to labeling peptides with other small molecule reagents. Overall, the bioconjugate chemistry is robust, selective, and modular, thereby potentiating the controlled conjugation of QDs with a diverse array of biomolecules for various applications.

  17. Surface ligation-based resonance light scattering analysis of methylated genomic DNA on a microarray platform.

    Science.gov (United States)

    Ma, Lan; Lei, Zhen; Liu, Xia; Liu, Dianjun; Wang, Zhenxin

    2016-05-10

    DNA methylation is a crucial epigenetic modification and is closely related to tumorigenesis. Herein, a surface ligation-based high throughput method combined with bisulfite treatment is developed for analysis of methylated genomic DNA. In this method, a DNA microarray is employed as a reaction platform, and resonance light scattering (RLS) of nanoparticles is used as the detection principle. The specificity stems from allele-specific ligation of Taq DNA ligase, which is further enhanced by improving the fidelity of Taq DNA ligase in a heterogeneous reaction. Two amplification techniques, rolling circle amplification (RCA) and silver enhancement, are employed after the ligation reaction and a gold nanoparticle (GNP) labeling procedure is used to amplify the signal. As little as 0.01% methylated DNA (i.e. 2 pmol L(-1)) can be distinguished from the cocktail of methylated and unmethylated DNA by the proposed method. More importantly, this method shows good accuracy and sensitivity in profiling the methylation level of genomic DNA of three selected colonic cancer cell lines. This strategy provides a high throughput alternative with reasonable sensitivity and resolution for cancer study and diagnosis.

  18. Real-Time NMR Studies of Oxyamine Ligations of Reducing Carbohydrates under Equilibrium Conditions.

    Science.gov (United States)

    Baudendistel, Oliver R; Wieland, Daniel E; Schmidt, Magnus S; Wittmann, Valentin

    2016-11-21

    Ligation reactions at the anomeric center of carbohydrates have gained increasing importance in the field of glycobiology. Oxyamines are frequently used in labeling, immobilization, and bioconjugation of reducing carbohydrates. Herein, we present a systematic investigation of these ligation reactions under aqueous conditions. A series of four unprotected monosaccharides (glucose, N-acetylglucosamine, mannose, and 2-deoxyglucose) and one disaccharide (N,N'-diacetylchitobiose) was reacted with three primary and one secondary oxyamine. We monitored the concentrations of the starting materials and products by (1) H NMR spectroscopy and determined reaction times and equilibrium yields. Our experiments show that the outcome of the ligation reaction is not only dependent on the sugar and oxyamine used but also strongly on the reaction conditions. In the case of glucose, lowering the pH from 6 to 3 led to steadily increasing reaction rates, whereas the yields were decreasing at the same time. Variation of the temperature did not only influence the product ratio in equilibrium but can also have a strong impact on the equilibrium yield. In the case of reactions of a primary oxyamine, increased temperatures led to a higher proportion of acyclic products. Reaction of the secondary oxyamine with glucose unexpectedly led to lower yields at higher temperatures.

  19. Arterial Ligation for Infected Femoral Psuedo-Aneurysm in Drug Injecting Abusers

    Directory of Open Access Journals (Sweden)

    Mohammadzade Mohammad Ali

    2009-10-01

    Full Text Available Pseudo-aneurysm of the femoral artery is the most common arterial complication in drug injecting abusers. Scholars in vascular surgery have published debating statements regarding techniques of successful surgical management during last two decades. We present the results of simple arterial ligation in a series of 32 patients presenting with infected femoral pseudo-aneurysm. Most of the patients were males (89%. Young persons in the age group of 15-44 years were mostly affected. Site of lesion included common femoral artery in 65% , superficial femoral artery 28% and at bifurcation 6.2%. celulitis in 14 (53%, abscess & "ncelulitis in 6 (19%, necrosing fasciitis in 2 (6.2% and vascular abscess in 7 (22% cases were the forms of associated local infection. There was no hemorrhage, vascular thrombosis, amputation, or mortality. Claudicating were the only complications identified in 2 patients with Tripe ligation. Ligation is the optimal management for infected pseudo-aneurysms because it is easy, cost-effective, and safe. Early reconstruction is not recommended, since there is an extended infection in the location of the pseudo-aneurysm.

  20. Comparison of Ligation-Mediated PCR Methods in Differentiation of Mycobacterium tuberculosis Strains

    Directory of Open Access Journals (Sweden)

    Anna Zaczek

    2014-01-01

    Full Text Available Fast and inexpensive identification of epidemiological links between limited number of Mycobacterium tuberculosis strains is required to initially evaluate hospital outbreaks, laboratory crosscontaminations, and family or small community transmissions. The ligation-mediated PCR methods (LM-PCR appear sufficiently discriminative and reproducible to be considered as a good candidate for such initial, epidemiological analysis. Here, we compared the discriminative power of the recently developed in our laboratory fast ligation amplification polymorphism (FLAP method with fast ligation-mediated PCR (FLiP. Verification of the results was based on analyzing a set of reference strains and RFLP-IS6110 typing. The HGDI value was very similar for both LM-PCR methods and RFLP-IS6110 typing. However, only 52% of strains were correspondingly grouped by both FLiP and FLAP methods. Differentiation by FLAP method demonstrated a limited similarity to IS6110-RFLP (37,7%. As much as 78,7% of strains were grouped identically when differentiated by FLiP and IS6110-RFLP methods. The analysis differentiated 31, 35, and 36 groups when using FLAP, FLiP, and RFLP-IS6110 methods, respectively.

  1. Synthesis, properties and drug potential of the photosensitive alkyl- and alkylsiloxy-ligated silicon phthalocyanine Pc 227.

    Science.gov (United States)

    Li, Jun; Yang, Yang; Zhang, Ping; Sounik, James R; Kenney, Malcolm E

    2014-12-01

    The photosensitive, alkyl- and alkylsiloxy-ligated silicon phthalocyanine, SiPc[(CH2)3SH][OSi(CH3)2(CH2)3N(CH3)2], Pc 227, has been prepared and characterized. This phthalocyanine yields the experimental photodynamic therapy (PDT) drug Pc 4, SiPc[OH][OSi(CH3)2(CH2)3N(CH3)2], when irradiated with red light. To provide an understanding of the process by which Pc 227 and other alkyl-alkylsiloxysilicon phthalocyanines such as Pc 227 are photolyzed, bond dissociation energy, natural bond orbital (NBO) charge distribution, spin density distribution, nucleus-independent chemical shift (NICS), and electron localization function (ELF) calculations have been carried out on two models related to it. These show that the lowest energy pathway for the photolysis of Pc 227 is a homolysis involving a phthalocyanine π radical having a low SiPc-C bond dissociation energy. The promise of the results of this study for synthetic chemistry and drug development is discussed.

  2. Studies of Wettability of Medical PVC by Remote Nitrogen Plasma

    Science.gov (United States)

    Li, Ru; Chen, Jierong

    2006-05-01

    The effects of remote nitrogen plasma and nitrogen plasma on medical PVC's surface modification are studied. The surface properties are characterized by the contact angle measurement, X-ray photoelectron spectroscopy and scanning electron microscopy. Results show that the remote nitrogen plasma treatments modify the PVC surface in both morphology and composition and the treatment by the remote nitrogen plasma in PVC surface modification is more effective than that by the nitrogen plasma. Remote nitrogen plasma can modify the surface more uniformly. After the PVC surface is treated for 2 min by remote nitrogen plasma, the [w(O)+ w(N)]/w(C)] value increases from 0.13 to 0.51 and the water contact angle decreases from 89o to 18o.

  3. Characterization and modeling of the intrinsic properties of 1.5-micrometer gallium indium nitrogen arsenic antimonide/gallium arsenide laser

    Science.gov (United States)

    Goddard, Lynford

    2005-12-01

    output power has also been demonstrated. Comparative experiments using innovative characterization techniques, such as: the multiple section absorption/gain method to explore the band structure, as well as the Z-parameter to analyze the dominant recombination processes, have identified the physical mechanisms responsible for improved performance. Also, by measuring the temperature dependence of relevant laser parameters, we have been able to simulate device operation while varying temperature and device geometry.

  4. Albert Behnke: nitrogen narcosis.

    Science.gov (United States)

    Grover, Casey A; Grover, David H

    2014-02-01

    As early as 1826, divers diving to great depths noted that descent often resulted in a phenomenon of intoxication and euphoria. In 1935, Albert Behnke discovered nitrogen as the cause of this clinical syndrome, a condition now known as nitrogen narcosis. Nitrogen narcosis consists of the development of euphoria, a false sense of security, and impaired judgment upon underwater descent using compressed air below 3-4 atmospheres (99 to 132 feet). At greater depths, symptoms can progress to loss of consciousness. The syndrome remains relatively unchanged in modern diving when compressed air is used. Behnke's use of non-nitrogen-containing gas mixtures subsequent to his discovery during the 1939 rescue of the wrecked submarine USS Squalus pioneered the use of non-nitrogen-containing gas mixtures, which are used by modern divers when working at great depth to avoid the effects of nitrogen narcosis.

  5. Universal strategies for the DNA-encoding of libraries of small molecules using the chemical ligation of oligonucleotide tags.

    Science.gov (United States)

    Litovchick, Alexander; Clark, Matthew A; Keefe, Anthony D

    2014-01-01

    The affinity-mediated selection of large libraries of DNA-encoded small molecules is increasingly being used to initiate drug discovery programs. We present universal methods for the encoding of such libraries using the chemical ligation of oligonucleotides. These methods may be used to record the chemical history of individual library members during combinatorial synthesis processes. We demonstrate three different chemical ligation methods as examples of information recording processes (writing) for such libraries and two different cDNA-generation methods as examples of information retrieval processes (reading) from such libraries. The example writing methods include uncatalyzed and Cu(I)-catalyzed alkyne-azide cycloadditions and a novel photochemical thymidine-psoralen cycloaddition. The first reading method "relay primer-dependent bypass" utilizes a relay primer that hybridizes across a chemical ligation junction embedded in a fixed-sequence and is extended at its 3'-terminus prior to ligation to adjacent oligonucleotides. The second reading method "repeat-dependent bypass" utilizes chemical ligation junctions that are flanked by repeated sequences. The upstream repeat is copied prior to a rearrangement event during which the 3'-terminus of the cDNA hybridizes to the downstream repeat and polymerization continues. In principle these reading methods may be used with any ligation chemistry and offer universal strategies for the encoding (writing) and interpretation (reading) of DNA-encoded chemical libraries.

  6. 氮气吸附法表征杨木应拉木的孔隙结构%Pore Structure Characterization of Poplar Tension Wood by Nitrogen Adsorption-Desorption Method

    Institute of Scientific and Technical Information of China (English)

    苌姗姗; 胡进波; Clair Bruno; Quignard Franqoise

    2011-01-01

    Based on the conventional anatomical analysis, the pore structures of poplar tension wood, such as specific surface area, pore volume and pore size distributions were characterized by nitrogen adsorption-desorption method. The shapes of the pores were estimated by nitrogen adsorption isotherms. The results show that poplar tension wood with BET specific surface area of 21. 9 m2 ·g-1, which is 13 times higher than that in opposite wood. Poplar tension wood has intact mesoporosity { pore size between 2-50 nm) with inkbottle and slit shape pore, as well as a certain amount of micropores and macropores. The maximum value of pore size distribution appears at 5 nm. The pore volume with diameter ranging from 4-7 nm makes up 74.4% of the total, and larger than 15 nm, 10. 8% . The high amount of mesopores can be attributed to the thick gelatinous layer in poplar tension wood.%在常规解剖特征分析的基础上,采用氮气吸附法对杨木应拉木的比表面积及孔径分布等孔结构参数进行研究,并通过解析氮气吸附等温线判断孔隙的形状.结果表明:杨木应拉木BET比表面积为21.9 m2·g-1,是对应木的13倍;杨木应拉木试样具有完好的介孔特征(孔径2~50 nm),并具有一定量的微孔和大孔;内部存在“墨水瓶”状和狭缝状孔隙,孔径为5 nm的孔体积分布密度最大,孔径在4~7 nm的孔体积占总孔体积的74.4%,孔径超过15 nm的孔体积占总体积的10.8%.杨木应拉木中大量存在的中孔孔隙可归因于应拉木木纤维中的厚壁胶质层.

  7. Caracterização espectral de Paspalum notatum em diferentes níveis de adubação nitrogenada Spectral characterization of Paspalum notatum under different nitrogen fertilization

    Directory of Open Access Journals (Sweden)

    Eliana Lima da Fonseca

    2002-03-01

    Full Text Available As propriedades espectrais da vegetação podem ser utilizadas para o monitoramento das condições de crescimento da vegetação ao longo do ano, assim como a estimativa da produtividade das espécies, por meio de técnicas de sensoriamento remoto. Para tanto, é necessário, primeiramente, caracterizar espectralmente as espécies que compõem a vegetação de um ecossistema. O objetivo deste trabalho foi caracterizar a reflectância do Paspalum notatum Flügge var. notatum crescendo em diferentes níveis de adubação nitrogenada. Foi realizado um experimento de campo na Estação Experimental Agronômica da Universidade Federal do Rio Grande do Sul (30º5'22'' S e 51º39'8'' W, utilizando-se um espectrorradiômetro portátil, em parcelas de P. notatum adubadas com 0, 200 e 400 kg ha-1 de N. A resposta espectral do P. notatum foi alterada pelas variações na quantidade de biomassa do dossel, provocadas por diferenças nos níveis de adubação nitrogenada. Os aumentos na quantidade de biomassa provocaram diminuição da reflectância na porção visível do espectro e aumento na porção infravermelho, o que mostra que a análise da reflectância é um bom indicador das mudanças que ocorrem em um dossel.Remote sensing techniques using spectral properties of canopies may be used to monitor vegetation growth conditions throughout the year, as well as to estimate the yield of different species. However, before these techniques can be used, it is necessary to establish the spectral properties of each of the different species which make up the landscape. The objective of this study was to characterize the spectral reflectance of Paspalum notatum Flügge var. notatum, growing on different levels of nitrogen fertilization. A field experiment was carried out at the Agronomic Experimental Station of Universidade Federal do Rio Grande do Sul, Brazil (30º5'22'' S, 51º39''8'' W, using a portable spectroradiometer, on plots with P. notatum fertilized

  8. Simulation of Soil-Plant Nitrogen Interactions for Educational Purposes.

    Science.gov (United States)

    Huck, M. G.; Hoeft, R. G.

    1994-01-01

    Describes a computer model characterizing the balance of soil-plant Nitrogen that allows students to see the likely consequences of different biological and weather-related parameters. Proposes three uses for the model: (1) orienting beginning students to understand the soil Nitrogen cycle; (2) providing information for advanced students; and (3)…

  9. Coenzyme B12 model studies: Equilibrium constants for the H-dependent axial ligation of benzyl(aquo)cobaloxime by various N- and S-donor ligands

    Indian Academy of Sciences (India)

    D Sudarshan Reddy; N Ravi Kumar Reddy; V Sridhar; S Satyanarayana

    2002-02-01

    Equilibria of the axial ligation of benzyl(aquo)cobaloximes by imidazole, 1-methyl imidazole, histidine, histamine, glycine, ethyl glycine ester, thiourea and urea have been spectrophotometrically measured in aqueous solutions of ionic strength 1.0 M (KCl) at 25°C as a function of H. The equilibrium constants are in the order CN- > 1-methyl imidazole > imidazole > histidine > histamine > glycine > ethyl glycine ester > thiourea > urea. The order of stability of benzyl(ligand)cobaloxime is explained based on the basicity of the ligand, Co(III) → - back bonding and soft-soft and soft-hard interaction. Imidazole, substituted imidazoles, histidine and histamine form more stable complexes than glycine, ethyl glycine ester in contrast to the basicity of the ligands. Benzyl(ligand)cobaloximes were isolated and characterized by elemental analysis, IR and 1H NMR spectra.

  10. Coenzyme B12 model studies: An HSAB approach to the equilibria and kinetics of axial ligation of alkyl(aquo)-cobaloximes by imidazole and cyanide

    Indian Academy of Sciences (India)

    Vaddeboina Sridhar; S Satyanarayana

    2000-12-01

    Kinetics and equilibria of the axial ligation of alkyl(aquo)cobaloximes by imidazole and cyanide have been measured spectrophotometrically in aqueous solutions of ionic strength 1.0 M at 25°C as a function of H. Comparison of IMD and CN- of CH3, C2H5 and BrCH2 cobaloximes indicates that their stability is in the order BrCH2 > CH3 > C2H5. As the electron-withdrawing capacity of the alkyl group trans to water increases, the electron density of the cobalt(III) decreases and thus it becomes a stronger Lewis acid and binds more strongly to imidazole and cyanide. The association and dissociation rate constants are better correlated to the relative softness of the ligand showing that cyanide binds 30 times faster than imidazole. These complexes are isolated and are characterized by IR and 1H NMR spectra.

  11. Nitrogen use efficiency (NUE)

    NARCIS (Netherlands)

    Oenema, O.

    2015-01-01

    There is a need for communications about resource use efficiency and for measures to increase the use efficiency of nutrients in relation to food production. This holds especially for nitrogen. Nitrogen (N) is essential for life and a main nutrient element. It is needed in relatively large quantitie

  12. High Nitrogen Stainless Steel

    Science.gov (United States)

    2011-07-19

    Kiev, 1993. 7. High Nitrogen Steels, edited by M. Kikuchi and Y. Mishima , Vol. 36, No. 7, Iron and Steel Institute of Japan Inernational, Tokyo...the Corrosion of Iron and Steels,” High Nitrogen Steels, edited by M. Kikuchi and Y. Mishima , Vol. 36, No. 7, Iron and Steel Institute of Japan

  13. Nitrogen trading tool

    Science.gov (United States)

    The nitrogen cycle is impacted by human activities, including those that increase the use of nitrogen in agricultural systems, and this impact can be seen in effects such as increased nitrate (NO3) levels in groundwater or surface water resources, increased concentration of nitrous oxide (N2O) in th...

  14. Nitrogen in Chinese coals

    Science.gov (United States)

    Wu, D.; Lei, J.; Zheng, B.; Tang, X.; Wang, M.; Hu, Jiawen; Li, S.; Wang, B.; Finkelman, R.B.

    2011-01-01

    Three hundred and six coal samples were taken from main coal mines of twenty-six provinces, autonomous regions, and municipalities in China, according to the resource distribution and coal-forming periods as well as the coal ranks and coal yields. Nitrogen was determined by using the Kjeldahl method at U. S. Geological Survey (USGS), which exhibit a normal frequency distribution. The nitrogen contents of over 90% Chinese coal vary from 0.52% to 1.41% and the average nitrogen content is recommended to be 0.98%. Nitrogen in coal exists primarily in organic form. There is a slight positive relationship between nitrogen content and coal ranking. ?? 2011 Science Press, Institute of Geochemistry, CAS and Springer Berlin Heidelberg.

  15. Increased Expression of TGF-β Signaling Components in a Mouse Model of Fibrosis Induced by Submandibular Gland Duct Ligation.

    Directory of Open Access Journals (Sweden)

    Lucas T Woods

    Full Text Available Transforming growth factor-β (TGF-β is a multi-functional cytokine with a well-described role in the regulation of tissue fibrosis and regeneration in the liver, kidney and lung. Submandibular gland (SMG duct ligation and subsequent deligation in rodents is a classical model for studying salivary gland damage and regeneration. While previous studies suggest that TGF-β may contribute to salivary gland fibrosis, the expression of TGF-β signaling components has not been investigated in relation to mouse SMG duct ligation-induced fibrosis and regeneration following ductal deligation. Following a 7 day SMG duct ligation, TGF-β1 and TGF-β3 were significantly upregulated in the SMG, as were TGF-β receptor 1 and downstream Smad family transcription factors in salivary acinar cells, but not in ductal cells. In acinar cells, duct ligation also led to upregulation of snail, a Smad-activated E-cadherin repressor and regulator of epithelial-mesenchymal transition, whereas in ductal cells upregulation of E-cadherin was observed while snail expression was unchanged. Upregulation of these TGF-β signaling components correlated with upregulation of fibrosis markers collagen 1 and fibronectin, responses that were inhibited by administration of the TGF-β receptor 1 inhibitors SB431542 or GW788388. After SMG regeneration following a 28 day duct deligation, TGF-β signaling components and epithelial-mesenchymal transition markers returned to levels similar to non-ligated controls. The results from this study indicate that increased TGF-β signaling contributes to duct ligation-induced changes in salivary epithelium that correlate with glandular fibrosis. Furthermore, the reversibility of enhanced TGF-β signaling in acinar cells of duct-ligated mouse SMG after deligation indicates that this is an ideal model for studying TGF-β signaling mechanisms in salivary epithelium as well as mechanisms of fibrosis initiation and their resolution.

  16. Hydrolytic Amino Acids Employed as a Novel Organic Nitrogen Source for the Preparation of PGPF-Containing Bio-Organic Fertilizer for Plant Growth Promotion and Characterization of Substance Transformation during BOF Production.

    Science.gov (United States)

    Zhang, Fengge; Meng, Xiaohui; Feng, Chenglong; Ran, Wei; Yu, Guanghui; Zhang, Yingjun; Shen, Qirong

    2016-01-01

    Opportunity costs seriously limit the large-scale production of bio-organic fertilizers (BOFs) both in China and internationally. This study addresses the utilization of amino acids resulting from the acidic hydrolysis of pig corpses as organic nitrogen sources to increase the density of TrichodermaharzianumT-E5 (a typical plant growth-promoting fungi, PGPF). This results in a novel, economical, highly efficient and environmentally friendly BOF product. Fluorescence excitation-emission matrix (EEM) spectroscopy combined with fluorescence regional integration (FRI) was employed to monitor compost maturity levels, while pot experiments were utilized to test the effects of this novel BOF on plant growth. An optimization experiment, based on response surface methodologies (RSMs), showed that a maximum T-E5 population (3.72 × 108 ITS copies g-1) was obtained from a mixture of 65.17% cattle manure compost (W/W), 19.33% maggot manure (W/W), 15.50% (V/W)hydrolytic amino acid solution and 4.69% (V/W) inoculum at 28.7°C after a 14 day secondary solid fermentation. Spectroscopy analysis revealed that the compost transformation process involved the degradation of protein-like substances and the formation of fulvic-like and humic-like substances. FRI parameters (PI, n, PII, n, PIII, n and PV, n) were used to characterize the degree of compost maturity. The BOF resulted in significantly higher increased chlorophyll content, shoot length, and shoot and root dry weights of three vegetables (cucumber, tomato and pepper) by 9.9%~22.4%, 22.9%~58.5%, 31.0%~84.9%, and 24.2%~34.1%, respectively. In summary, this study presents an operational means of increasing PGPF T-E5 populations in BOF to promote plant growth with a concomitant reduction in production cost. In addition, a BOF compost maturity assessment using fluorescence EEM spectroscopy and FRI ensured its safe field application.

  17. Hydrolytic Amino Acids Employed as a Novel Organic Nitrogen Source for the Preparation of PGPF-Containing Bio-Organic Fertilizer for Plant Growth Promotion and Characterization of Substance Transformation during BOF Production.

    Directory of Open Access Journals (Sweden)

    Fengge Zhang

    Full Text Available Opportunity costs seriously limit the large-scale production of bio-organic fertilizers (BOFs both in China and internationally. This study addresses the utilization of amino acids resulting from the acidic hydrolysis of pig corpses as organic nitrogen sources to increase the density of TrichodermaharzianumT-E5 (a typical plant growth-promoting fungi, PGPF. This results in a novel, economical, highly efficient and environmentally friendly BOF product. Fluorescence excitation-emission matrix (EEM spectroscopy combined with fluorescence regional integration (FRI was employed to monitor compost maturity levels, while pot experiments were utilized to test the effects of this novel BOF on plant growth. An optimization experiment, based on response surface methodologies (RSMs, showed that a maximum T-E5 population (3.72 × 108 ITS copies g-1 was obtained from a mixture of 65.17% cattle manure compost (W/W, 19.33% maggot manure (W/W, 15.50% (V/Whydrolytic amino acid solution and 4.69% (V/W inoculum at 28.7°C after a 14 day secondary solid fermentation. Spectroscopy analysis revealed that the compost transformation process involved the degradation of protein-like substances and the formation of fulvic-like and humic-like substances. FRI parameters (PI, n, PII, n, PIII, n and PV, n were used to characterize the degree of compost maturity. The BOF resulted in significantly higher increased chlorophyll content, shoot length, and shoot and root dry weights of three vegetables (cucumber, tomato and pepper by 9.9%~22.4%, 22.9%~58.5%, 31.0%~84.9%, and 24.2%~34.1%, respectively. In summary, this study presents an operational means of increasing PGPF T-E5 populations in BOF to promote plant growth with a concomitant reduction in production cost. In addition, a BOF compost maturity assessment using fluorescence EEM spectroscopy and FRI ensured its safe field application.

  18. Molecular Biology of Nitrogen Fixation

    Science.gov (United States)

    Shanmugam, K. T.; Valentine, Raymond C.

    1975-01-01

    Reports that as a result of our increasing knowledge of the molecular biology of nitrogen fixation it might eventually be possible to increase the biological production of nitrogenous fertilizer from atmospheric nitrogen. (GS)

  19. [Post-translational ligation of split CFTR severed before TMD2 and its chloride channel function].

    Science.gov (United States)

    Zhu, Fuxiang; Gong, Xiandi; Liu, Zelong; Yang, Shude; Qu, Huige; Chi, Xiaoyan

    2010-12-01

    Mutations of cystic fibrosis transmembrane conductance regulator (CFTR) gene leads to cystic fibrosis, an autosomal recessive genetic disorder affecting a number of organs including the lung airways, pancreas and sweat glands. In order to investigate the post-translational ligation of CFTR with reconstructed functional chloride ion channel and the split Ssp DnaB intein-mediated protein trans-splicing was explored to co-deliver CFTR gene into eukaryotic cells with two vectors. The human CFTR cDNA was split after Glu838 codon before the second transmembrane dome (TMD2) into two halves of N- and C-parts and fused with the coding sequences of split Ssp DnaB intein. Pair of eukaryotic expression vectors pEGFP-NInt and pEYFP-IntC were constructed by inserting them into the vectors pEGFP-N1 and pEYFP-N1 respectively. The transient expression was carried out for observing the ligation of CFTR by Western blotting and recording the chloride current by patch clamps when cotransfection of the pair of vectors into baby hamster kidney (BHK) cells. The results showed that an obvious protein band proven to be ligated intact CFTR can be seen and a higher chloride current and activity of chloride channel were recorded after cotransfection. These data demonstrated that split Ssp DnaB intein could be used as a strategy in delivering CFTR gene by two vectors providing evidence for application of dual adeno-associated virus (AAV) vectors to overcome the limitation of packaging size in cystic fibrosis gene therapy.

  20. Evidence of Liquid Crystal-Assisted Abiotic Ligation of Nucleic Acids

    Science.gov (United States)

    Fraccia, Tommaso P.; Zanchetta, Giuliano; Rimoldi, Valeria; Clark, Noel A.; Bellini, Tommaso

    2015-06-01

    The emergence of early life must have been marked by the appearance in the prebiotic era of complex molecular structures and systems, motivating the investigation of conditions that could not only facilitate appropriate chemical synthesis, but also provide the mechanisms of molecular selection and structural templating necessary to pilot the complexification toward specific molecular patterns. We recently proposed and demonstrated that these functions could be afforded by the spontaneous ordering of ultrashort nucleic acids oligomers into Liquid Crystal (LC) phases. In such supramolecular assemblies, duplex-forming oligomers are held in average end-to-end contact to form chemically discontinuous but physically continuous double helices. Using blunt ended duplexes, we found that LC formation could both provide molecular selection mechanisms and boost inter-oligomer ligation. This paper provides an essential extension to this notion by investigating the catalytic effects of LC ordering in duplexes with mutually interacting overhangs. Specifically, we studied the influence of LC ordering of 5'-hydroxy-3'-phosphate partially self-complementary DNA 14mers with 3'-CG sticky-ends, on the efficiency of non-enzymatic ligation reaction induced by water-soluble carbodiimide EDC as condensing agent. We investigated the ligation products in mixtures of DNA with poly-ethylene glycol (PEG) at three PEG concentrations at which the system phase separates creating DNA-rich droplets that organize into isotropic, nematic LC and columnar LC phases. We observe remarkable LC-enhanced chain lengthening, and we demonstrate that such lengthening effectively promotes and stabilizes LC domains, providing the kernel of a positive feedback cycle by which LC ordering promotes elongation, in turn stabilizing the LC ordering.

  1. Intermolecular DNA ligation activity of eukaryotic toposiomerase II: Potential roles in nucleic acid recombination

    Energy Technology Data Exchange (ETDEWEB)

    Gale, K.C.R.

    1992-01-01

    Single-stranded [phi]X174 (+) strand DNA was used as a model substrate for topoisomerase II to determine whether double-stranded DNA cleavage observed in vitro reflects the in vivo intermediate in the enzyme's catalytic cycle and to investigate potential mechanisms for topoisomerase II-mediated DNA recombination. As found previously for topoisomerase II-mediated cleavage of double-stranded DNA, the enzyme was covalently linked to the 5[prime]-termini of cleaved [phi]X174 molecules. Optimal reaction conditions were similar for the two substrates. In contrast to results with double-stranded molecules, single-stranded DNA cleavage increased with time, was not reversible, and did not require the presence of SDS. Cleavage products generated in the absence of protein denaturant contained free 3[prime]-OH DNA termini. These results strongly suggest that the covalent topoisomerase II-cleaved DNA complex observed in vitro is the active intermediate in the enzyme's catalytic code. Topoisomerase II is capable of joining cleaved [phi]X174 (+) strand DNA to duplex oligonucleotide acceptor molecules by an intermolecular ligation reaction. Intermolecular DNA ligation proceeded in a time and oligonucleotide concentration dependent fashion. The covalent linkage is between the 5[prime]-phosphate of [phi]X174 (+) strand DNA and the 3[prime]-OH of oligonucleotide acceptor molecules. The reaction was dependent on the presence of a divalent cation, was inhibited by salt, and was not affected by the presence of ATP. The enzyme was capable of ligating [phi]X174 (+) strand DNA to double-stranded oligonucleotides that contained 5[prime]-overhang, 3[prime]-overhang, or blunt ends. Single-stranded, nicked, or gapped oligonucleotides could also be used as acceptor molecules. These results demonstrate that the type II enzyme has an intrinsic ability to mediate illegitimate DNA recombination in vitro and suggests possible roles for topoisomerase II in nucleic acid recombination in vivo.

  2. Application of a pig ligated intestinal loop model for early Lawsonia intracellularis infection

    Directory of Open Access Journals (Sweden)

    Agerholm Jørgen S

    2010-02-01

    Full Text Available Abstract Background Porcine proliferative enteropathy in pigs is caused by the obligate, intracellular bacterium Lawsonia intracellularis. In vitro studies have shown close bacterium-cell interaction followed by cellular uptake of the bacterium within 3 h post inoculation (PI. However, knowledge of the initial in vivo interaction between porcine intestinal epithelium and the bacterium is limited. The aims of the present study were to evaluate the usefulness of a ligated small intestinal loop model to study L. intracellularis infections and to obtain information on the very early L. intracellularis-enterocyte interactions. Methods A ligated small intestinal loop model using three different L. intracellularis inocula was applied to 10-11-week-old pigs. The inocula were 1 wild type bacteria derived from overnight incubation of L. intracellularis bacteria from spontaneous disease, 2 crude vaccine bacteria (Enterisol® Ileitis Vet, and 3 vaccine bacteria propagated in cell culture. The bacteria-enterocyte interaction was visualised using immunohistochemistry on specimens derived 1, 3 and 6 h PI respectively. Results Although at a low level, close contact between bacteria and the enterocyte brush border including intracellular uptake of bacteria in mature enterocytes was seen at 3 and 6 h PI for the vaccine and the propagated vaccine inocula. Interaction between the wild-type bacteria and villus enterocytes was scarce and only seen at 6 h PI, where a few bacteria were found in close contact with the brush border. Conclusions The ligated intestinal loop model was useful with respect to maintaining an intact intestinal morphology for up to 6 h. Furthermore, the study demonstrated that L. intracellularis interacts with villus enterocytes within 3 to 6 h after inoculation into intestinal loops and that the bacterium, as shown for the vaccine bacteria, propagated as well as non-propagated, was able to invade mature enterocytes. Thus, the study demonstrates

  3. [Post-translational ligation and function of dual-vector transferred split CFTR gene].

    Science.gov (United States)

    Zhu, Fu-Xiang; Liu, Ze-Long; Qu, Hui-Ge; Chi, Xiao-Yan

    2010-01-01

    The mutation of cystic fibrosis transmembrane conductance regulator (CFTR) gene leads to an autosomal recessive genetic disorder cystic fibrosis (CF). The gene therapy for CF using adeno-associated virus (AAV) vectors delivering CFTR gene is restricted by the contents limitation of AAV vectors. In this study the split CFTR genes severed at its regulatory domain were delivered by a dual-vector system with an intein-mediated protein trans-splicing as a technique to investigate the post-translational ligation of CFTR half proteins and its function as a chloride ion channel. A pair of eukaryotic expression vectors was constructed by breaking the human CFTR cDNA before Ser712 codon and fusing with Ssp DnaB intein coding sequences. After co-transfection into baby hamster kidney (BHK) cells followed by transient expression, patch clamps were carried out to record the chloride current of whole-cell and the activity of a single channel, and the ligation of two halves of CFTR was observed by Western blotting. The results showed that the intein-fused half genes co-transfected cells displayed a high whole cell chloride current and activity of a single channel indicating the functional recovery of chloride channel, and an intact CFTR protein band was figured out by CFTR-specific antibodies indicating that intein can efficiently ligate the separately expressed half CFTR proteins. The data demonstrated that protein splicing strategy could be used as a strategy in delivering CFTR gene by two vectors, encouraging our ongoing research program on dual AAV vector system based gene transfer in gene therapy for cystic fibrosis.

  4. Modeling nitrogen fluxes in Germany - where does the nitrogen go?

    Science.gov (United States)

    Klement, Laura; Bach, Martin; Breuer, Lutz

    2016-04-01

    According to the latest inventory of the EU Water Framework Directive, 26.3% of German groundwater bodies are in a poor chemical state regarding nitrate. Additionally, the EU initiated infringement proceedings against Germany for not meeting the quality standards of the EU Nitrate Directive. Agriculture has been determined as the main source of nitrate pollution due to over-fertilization and regionally high density of livestock farming. The nitrogen balance surplus is commonly used as an indicator characterizing the potential of nitrate leaching into groundwater bodies and thus also serves as a foundation to introduce legislative restrictions or to monitor the success of mitigation measures. Currently, there is an ongoing discussion which measures are suitable for reducing the risk of nitrate leaching and also to what extent. However, there is still uncertainty about just how much the nitrogen surplus has to be reduced to meet the groundwater quality standards nationwide. Therefore, the aims of our study were firstly to determine the level of the nitrogen surplus that would be acceptable at the utmost and secondly whether the currently discussed target value of 30 kg N per hectare agricultural land for the soil surface nitrogen balance would be sufficient. The models MONERIS (Modeling Nutrient Emissions in River System) and MoRE (Modelling of Regionalized Emissions), the latter based on the first, are commonly used for estimating nitrogen loads into the river system in Germany at the mesoscale, as well as the effect of mitigation measures in the context of the EU directive 2008/105/EC (Environmental quality standards applicable to surface water). We used MoRE to calculate nitrate concentration for 2759 analytical units in Germany. Main factors are the surplus of the soil surface nitrogen balance, the percolation rate and an exponent representing the denitrification in the vadose zone. The modeled groundwater nitrate concentrations did not correspond to the regional

  5. A new resorbable device for ligation of blood vessels - A pilot study

    Directory of Open Access Journals (Sweden)

    Borg Niklas

    2011-07-01

    Full Text Available Abstract Background During surgery, controlled haemostasis to prevent blood loss is vital for a successful outcome. It can be difficult to ligate vessels located deep in the abdomen. A device that is easy to use and enables secure ligatures could be beneficial. Cable ties made of nylon have been used for ligation but the non-resorbable material caused tissue reactions. The objective of this study was to use a resorbable material to construct a device with a self-locking mechanism and to test its mechanical strength and ligation efficiency. Methods The device was manufactured by injection moulding of polydioxanone, a resorbable polymer used for suture materials. Polydioxanone with inherent viscosities of 1.9 dL/g and 1.3 dL/g were tested. The device consisted of a perforated flexible band which could be pulled through a case with a locking mechanism. After a first version of the device had been tested, some improvements were made. The locking case was downsized, corners were rounded off, the band was made thicker and the mould was redesigned to produce longer devices. Tensile tests were performed with the second version. The first version of the device was used to ligate the ovarian pedicle in a euthanized dog and to test echogenicity of the device with ultrasound. Compression of vessels of the ovarian pedicle was examined by histology. Both versions of the device were tested for haemostasis of and tissue grip on renal arteries in six anaesthetised pigs. Results The tensile strength of the flexible band of the devices with inherent viscosity of 1.9 dL/g was 50.1 ± 5.5 N (range 35.2-62.9 N, n = 11 and the devices with inherent viscosity of 1.3 dL/g had a tensile strength of 39.8 ± 8.1 N (range 18.6-54.2 N, n = 11. Injection moulding of the polymer with lower inherent viscosity resulted in a longer flow distance. Both versions of the device had an effective tissue grip and complete haemostasis of renal arteries was verified. The device attached

  6. Ligation of lymph vessels for the treatment of recurrent inguinal lymphoceles following lymphadenectomy

    DEFF Research Database (Denmark)

    Toyserkani, Navid Mohamadpour; Nielsen, Henrik Toft; Bakholdt, Vivi;

    2016-01-01

    used this technique since 2007 in our very severe cases and herein present our results. METHODS: The study was a retrospective case series in a university hospital setting. All patients who had this procedure performed were included from the first procedure performed in 2007 until August 2015......, and their data was retrieved from electronic patient records. RESULTS: In total, eight patients had this procedure performed for a total of ten inguinal regions. In all regions, leaking lymph vessels were easily found by the blue color and a median of 3 (range 1-5 vessels) vessels per region were ligated using...

  7. Biomimetic Synthesis of Insulin Enabled by Oxime Ligation and Traceless "C-Peptide" Chemical Excision.

    Science.gov (United States)

    Thalluri, Kishore; Kou, Binbin; Gelfanov, Vasily; Mayer, John P; Liu, Fa; DiMarchi, Richard D

    2017-02-03

    For decades, insulin has represented a preeminent synthetic target. Recently introduced "biomimetic" strategies based on convertible single-chain precursors require incorporation of a chemical linker or a unique proteolytic site, which limits their practicality. In this approach the A- and B-chains are linked by two sequential oxime ligations followed by disulfide bond formation under redox conditions and linker excision by diketopiperazine (DKP) formation and ester hydrolysis, yielding native two-chain insulin. The method is expected to be applicable to any member of the insulin superfamily.

  8. Ligation-based mutation detection and RCA in surface un-modified OSTE+ polymer microfluidic chambers

    DEFF Research Database (Denmark)

    Saharil, Farizah; Ahlford, Annika; Kuhnemund, Malte;

    2013-01-01

    For the first time, we demonstrate DNA mutation detection in surface un-modified polymeric microfluidic chambers without suffering from bubble trapping or bubble formation. Microfluidic devices were manufactured in off-stoichiometry thiol-ene epoxy (OSTE+) polymer using an uncomplicated and rapid...... fabrication scheme. The device performance was compared to that of PMMA and PDMS devices. In OSTE+ devices, we were able to perform ligation-based mutation detection and rolling circle amplification (RCA) assays directly on the un-modified surface without suffering from bubble formation or enzyme inhibition...... during bio-operation at elevated temperatures. In contrast, PMMA, PDMS and COP microfluidic devices required specific surface treatment....

  9. Multiplexed homogeneous proximity ligation assays for high throughput protein biomarker research in serological material

    DEFF Research Database (Denmark)

    Lundberg, Martin; Thorsen, Stine Buch; Assarsson, Erika;

    2011-01-01

    A high throughput protein biomarker discovery tool has been developed based on multiplexed proximity ligation assays (PLA) in a homogeneous format in the sense of no washing steps. The platform consists of four 24-plex panels profiling 74 putative biomarkers with sub pM sensitivity each consuming...... only 1 micro Litre of human plasma sample. The system uses either matched monoclonal antibody pairs or the more readily available single batches of affinity purified polyclonal antibodies to generate the target specific reagents by covalently linking with unique nucleic acid sequences. These paired...

  10. Ligation of MHC class I molecules on peripheral blood T lymphocytes induces new phenotypes and functions

    DEFF Research Database (Denmark)

    Bregenholt, S; Röpke, M; Skov, S;

    1996-01-01

    Microgram concentrations of immobilized anti-MHC class I (MHC-I) Ab induced proliferation of resting CD3+ T cells from peripheral blood. In contrast, soluble Ab did not activate T cells. Exposure of T cells to immobilized anti-MHC-I Ab for only 24 h was followed by proliferation and development....... These data clearly demonstrate that ligation of the MHC-I complex on T cells may induce both positive and negative signals. Since the physiologic ligands for MHC-I molecules are TCR and the CD8 molecules, our data may suggest that MHC-I molecules are instrumental in cellular interactions between T cells....

  11. Management of anal fistula by ligation of the intersphincteric fistula tract

    DEFF Research Database (Denmark)

    Zirak-Schmidt, Samira; Perdawood, Sharaf

    2014-01-01

    INTRODUCTION: Ligation of the intersphincteric fistula tract (LIFT) is a sphincter-preserving procedure for treatment of anal fistulas described in 2007 by Rojanasakul et al. Several studies have since then assessed the procedure with varied results. This review assesses the relevant literature...... fistula treatment techniques were excluded. Only reports in English were included. Most reports were case studies with no control groups. One report could not be retrieved. RESULTS: A total of 19 original reports were assessed. Details concerning preoperative assessment, antibiotic usage and tract...

  12. Evaluation of seamless ligation cloning extract preparation methods from an Escherichia coli laboratory strain.

    Science.gov (United States)

    Okegawa, Yuki; Motohashi, Ken

    2015-10-01

    Seamless ligation cloning extract (SLiCE) is a simple and efficient method for DNA cloning without the use of restriction enzymes. Instead, SLiCE uses homologous recombination activities from Escherichia coli cell lysates. To date, SLiCE preparation has been performed using an expensive commercially available lytic reagent. To expand the utility of the SLiCE method, we evaluated different methods for SLiCE preparation that avoid using this reagent. Consequently, cell extracts prepared with buffers containing Triton X-100, which is a common and low-cost nonionic detergent, exhibited sufficient cloning activity for seamless gene incorporation into a vector.

  13. Effects of urban stream burial on nitrogen uptake and ecosystem metabolism: implications for watershed nitrogen and carbon fluxes

    Science.gov (United States)

    Urbanization has resulted in extensive burial and channelization of headwater streams, yet little is known about impacts on stream ecosystem functions critical for reducing downstream nitrogen pollution. To characterize the biogeochemical impact of stream burial, we measured NO3...

  14. Ligational behavior of Schiff bases towards transition metal ion and metalation effect on their antibacterial activity.

    Science.gov (United States)

    Devi, Jai; Batra, Nisha; Malhotra, Rajesh

    2012-11-01

    New Schiff bases pyrazine-2-carboxylicacid (phenyl-pyridin-2-yl-methylene)-hydrazide (Hpch-bp) HL(1) and pyrazine-2-carboxylicacid (pyridin-2-ylmethylene)-hydrazide (Hpch-pc) HL(2) derived from condensation of pyrazine carboxylic hydrazide (Hpch) with 2-benzoyl pyridine (bp) or pyridine 2-carbaldehyde (pc) and their transition metal complexes of type ML((1-2)2) have been synthesized, where M=Mn(II), Co(II), Ni(II), Cu(II) and Zn(II). Characterization of ligands and their metal complexes was carried out by elemental analysis, conductimetric studies, magnetic susceptibility, spectroscopic techniques (IR, UV-VIS, NMR, ESR, Mass) and thermogravimetric analysis. The physico-chemical studies revealed octahedral geometry or distorted octahedral geometry around metal ion. These azomethine Schiff base ligands acted as tridentate coordinating through carbonyl, azomethine and pyridine nitrogen present in the ligand. The thermodynamic and thermal properties of the complexes have been investigated and it was observed on the basis of these studies that thermal stability of complexes follows the order Mnantibacterial activity at different concentrations against bacteria viz. Gram positive Bacillus subtilis, Micrococcus luteus and Gram negative Pseudomonas aeruginosa, Pseudomonas mendocina. A marked enhancement in biocidal activity of the ligands under similar experimental conditions was observed as a consequence of coordination with metal ions. The trend of growth inhibition in the complexes was found to be in the order: Cu>Mn>Ni>Co>Zn.

  15. Ligational behavior of Schiff bases towards transition metal ion and metalation effect on their antibacterial activity

    Science.gov (United States)

    Devi, Jai; Batra, Nisha; Malhotra, Rajesh

    2012-11-01

    New Schiff bases pyrazine-2-carboxylicacid (phenyl-pyridin-2-yl-methylene)-hydrazide (Hpch-bp) HL1 and pyrazine-2-carboxylicacid (pyridin-2-ylmethylene)-hydrazide (Hpch-pc) HL2 derived from condensation of pyrazine carboxylic hydrazide (Hpch) with 2-benzoyl pyridine (bp) or pyridine 2-carbaldehyde (pc) and their transition metal complexes of type ML(1-2)2 have been synthesized, where M = Mn(II), Co(II), Ni(II), Cu(II) and Zn(II). Characterization of ligands and their metal complexes was carried out by elemental analysis, conductimetric studies, magnetic susceptibility, spectroscopic techniques (IR, UV-VIS, NMR, ESR, Mass) and thermogravimetric analysis. The physico-chemical studies revealed octahedral geometry or distorted octahedral geometry around metal ion. These azomethine Schiff base ligands acted as tridentate ? coordinating through carbonyl, azomethine and pyridine nitrogen present in the ligand. The thermodynamic and thermal properties of the complexes have been investigated and it was observed on the basis of these studies that thermal stability of complexes follows the order Mn complexes were tested for in vitro antibacterial activity at different concentrations against bacteria viz. Gram positive Bacillus subtilis, Micrococcus luteus and Gram negative Pseudomonas aeruginosa, Pseudomonas mendocina. A marked enhancement in biocidal activity of the ligands under similar experimental conditions was observed as a consequence of coordination with metal ions. The trend of growth inhibition in the complexes was found to be in the order: Cu > Mn > Ni > Co > Zn.

  16. CHARACTERIZATIONS OF NITROGEN COMPOUNDS IN COKER GAS OIL AND STRAIGHT RUN DIESEL OIL%直馏柴油和焦化柴油中含氮化合物类型分布

    Institute of Scientific and Technical Information of China (English)

    张月琴

    2013-01-01

    Nitrogen compounds were extracted from coker gas oil and straight run diesel oil by chro-matography with neutral silica adsorption column. Then the nitrogen compounds were concentrated and separated into basic and non-basic types using acid-modified silica column. The identification of nitrogen compounds in the extracts was performed by gas chromatography-mass spectrometer (GC-MS) and gas chromatography-nitrogen chemiluminescence detection (GC-NCD), as well as verification of peak assignments with those reported by others. Results showed that in straight-run diesel, neutral nitrogen compounds, mainly benzocarbazole nitrogen compounds, occupied more than 70% (mass fraction) of the total nitrogen compounds; in coker gas oil, nitrogen compounds including pyridine, aniline, indole, quin-oline, and carbazole were found, and the mass fraction of total neutral nitrogen compounds was slightly over that of basic nitrogen compounds occupied more than 50% of the total nitrogen compounds.%采用中性硅胶柱分离、富集直馏柴油和焦化柴油中的含氮化合物,进一步用酸改性硅胶柱将含氮化合物分离成碱性含氮化合物和中性含氮化合物,利用GC-MS定性,结合含氮化合物的GC保留特性和沸点分布规律,确定直馏柴油和焦化柴油中含氮化合物的类型.结果表明,直馏柴油中中性含氮化合物占总含氮化合物的质量分数在70%以上,主要是苯并咔唑类含氮化合物;焦化柴油中含氮化合物包括吡啶类、苯胺类、吲哚类、喹啉类和咔唑类等含氮化合物,其中中性含氮化合物的含量比碱性含氮化合物稍高,占总含氮化合物的质量分数在50%以上.

  17. Expression, purification and biochemical characterization of Methanocaldococcus jannaschii DNA ligase.

    Science.gov (United States)

    Wang, You; Xie, Juan-Juan; Han, Zhong; Liu, Jian-Hua; Liu, Xi-Peng

    2013-02-01

    We describe the biochemical characterization of Methanocaldococcus jannaschii (M. jannaschii) DNA ligase and its potential application in single nucleotide polymorphism (SNP) genotyping. The recombinant M. jannaschii DNA ligase is an ATP-dependent ligase. The ligase activity was dependent on metal ions of Mg(2+) and Mn(2+). The optimal concentrations of ATP cofactor and Mg(2+) ion were 0.01-2 and 10 mM, respectively. The optimal pH value for DNA ligation was 8.5. High concentrations of NaCl inhibited DNA ligation. The effects of mismatches on joining short oligonucleotides by M. jannaschii DNA ligase were fully characterized. The mismatches at the first position 5' to the nick inhibited ligation more than those at the first position 3' to the nick. The mismatches at other positions 5' to the nick (3rd to 7th sites) exhibited less inhibition on ligation. However, the introduction of a C/C mismatch at the third position 5' to the nick could completely inhibit the ligation of the terminal-mismatched nick of an oligonucleotide duplex by M. jannaschii DNA ligase. Therefore, introducing an additional mismatch at the third position 5' to the SNP site is a more effective approach in genotyping by M. jannaschii DNA ligase.

  18. A pilot randomized control study to evaluate endoscopic resection using a ligation device for rectal carcinoid tumors

    Institute of Scientific and Technical Information of China (English)

    Hiroyuki Sakata; Sadahiro Amemori; Kotaro Mannen; Masanobu Mizuguchi; Kazuma Fujimoto; Ryuichi Iwakiri; Akifumi Ootani; Seiji Tsunada; Shinichi Ogata; Hibiki Ootani; Ryo Shimoda; Kanako Yamaguchi; Yasuhisa Sakata

    2006-01-01

    AIM: Rectal carcinoid tumors smaller than 10 mm can be resected with local excision using endoscopy. In order to remove rectal carcinoid tumors completely, we evaluated endoscopic mucosal resection with a ligation device in this pilot control randomized study.METHODS: Fifteen patients were diagnosed with rectal carcinoid tumor (less than 10 mm) in our hospital from 1993 to 2002. There were 9 males and 6 females,with a mean age 61.5 years (range, 34-77 years).The patientshad no complaints of carcinoid syndrome symptoms. Fifteen patients were randomly divided into 2 groups: 7 carcinoid tumors were treated by conventional endoscopic resection, and 8 carcinoid tumors were treated by endoscopic resection using a ligation device.RESULTS: All rectal carcinoid tumors were located at the middle to distal rectum. The size of the tumors varied from 3 mm to 10 mm and background characteristics of the patients were not different in the two groups.The rate of complete removal of carcinoid tumors using a ligation device (100%, 8/8) was significantly higher than that of conventional endoscopic resection (57.1%,4/7). The three patients had tumor involvement of deep margin, for which additional treatment was performed.No complications occurred during or after endoscopic resection using a ligation device. All patients in the both groups were alive during the 3-year observation period.CONCLUSION: Endoscopic resection using a ligation device is a useful and safe method for resection of small rectal carcinoid tumors.

  19. Alterations in plaque accumulation and gingival inflammation promoted by treatment with self-ligating and conventional orthodontic brackets

    Directory of Open Access Journals (Sweden)

    Mauricio de Almeida Cardoso

    2015-04-01

    Full Text Available OBJECTIVE: The aim of the present study was to evaluate, comparatively, the periodontal response during orthodontic treatment performed with self-ligating and conventional brackets. METHODS: Sixteen Caucasian individuals of both sexes, aged between 12 and 16 years old and in permanent dentition were selected. Eight individuals were treated with conventional brackets installed on the lower dental arch and self-ligating brackets on the upper arch. Another eight individuals received self-ligating brackets in the lower arch and conventional brackets in the upper arch. The subjects received material and instructions for oral hygiene. Visible plaque index (VPI, gingival bleeding index (GBI and clinical attachment level (CAL were evaluated just after installation of orthodontic appliances, and 30, 60 and 180 days later. Mann-Whitney test was used to compare differences between groups (self-ligating and conventional, two-way ANOVA followed by Tukey's test was used to assess CAL at each site of each tooth. Significance level was set at 5%. RESULTS: No significant changes were found with regard to the assessed parameters (VPI, GBI and CAL in either one of the systems. CONCLUSION: No significant changes were found with regard to the periodontal response to orthodontic treatment for the variables assessed and between subjects receiving passive self-ligating and conventional brackets. All individuals had received oral hygiene instructions and had their periodontal conditions monitored.

  20. Sensitive detection of mRNA decay products by use of reverse-ligation-mediated PCR (RL-PCR).

    Science.gov (United States)

    Grange, Thierry

    2008-01-01

    Ligation-mediated PCR allows the detection and mapping of cleavage products of specific nucleic acid molecules out of complex nucleic acid mixtures. It can be applied to the detection of either degradation products of exogenously added nucleases in footprinting applications or natural decay products or reaction intermediates. We have developed various ligation-mediated PCR approaches to analyze mRNAs, all relying on RNA ligation, followed by reverse-transcription and PCR amplification. We have termed these approaches reverse-ligation-mediated PCR (RL-PCR). The ligation event involves either an RNA linker added to the 5'-end of cleaved RNA or RNA circularization, allowing, respectively, the mapping and quantification of the cleavage points or the simultaneous analysis of the presence or absence of the 5'-cap structure and the length of the poly(A) tail. These methods enabled us to develop a very efficient 5'-RACE procedure to map mRNA 5'-ends, to footprint in permeabilized cells the interaction of regulatory proteins with RNA, to detect the products of cellular ribozyme action and to analyze cellular decay pathways that involve deadenylation and/or decapping. I review herein the methodologic aspects and protocols of the various RL-PCR procedures we have developed.

  1. Nitrogen Backbone Oligomers.

    Science.gov (United States)

    Wang, Hongbo; Eremets, Mikhail I; Troyan, Ivan; Liu, Hanyu; Ma, Yanming; Vereecken, Luc

    2015-08-19

    We found that nitrogen and hydrogen directly react at room temperature and pressures of ~35 GPa forming chains of single-bonded nitrogen atom with the rest of the bonds terminated with hydrogen atoms - as identified by IR absorption, Raman, X-ray diffraction experiments and theoretical calculations. At releasing pressures below ~10 GPa, the product transforms into hydrazine. Our findings might open a way for the practical synthesis of these extremely high energetic materials as the formation of nitrogen-hydrogen compounds is favorable already at pressures above 2 GPa according to the calculations.

  2. Mineral commodity profiles: nitrogen

    Science.gov (United States)

    Kramer, Deborah A.

    2004-01-01

    Overview -- Nitrogen (N) is an essential element of life and a part of all animal and plant proteins. As a part of the DNA and RNA molecules, nitrogen is an essential constituent of each individual's genetic blueprint. As an essential element in the chlorophyll molecule, nitrogen is vital to a plant's ability to photosynthesize. Some crop plants, such as alfalfa, peas, peanuts, and soybeans, can convert atmospheric nitrogen into a usable form by a process referred to as 'fixation.' Most of the nitrogen that is available for crop production, however, comes from decomposing animal and plant waste or from commercially produced fertilizers. Commercial fertilizers contain nitrogen in the form of ammonium and/or nitrate or in a form that is quickly converted to the ammonium or nitrate form once the fertilizer is applied to the soil. Ammonia is generally the source of nitrogen in fertilizers. Anhydrous ammonia is commercially produced by reacting nitrogen with hydrogen under high temperatures and pressures. The source of nitrogen is the atmosphere, which is almost 80 percent nitrogen. Hydrogen is derived from a variety of raw materials, which include water, and crude oil, coal, and natural gas hydrocarbons. Nitrogen-based fertilizers are produced from ammonia feedstocks through a variety of chemical processes. Small quantities of nitrates are produced from mineral resources principally in Chile. In 2002, anhydrous ammonia and other nitrogen materials were produced in more than 70 countries. Global ammonia production was 108 million metric tons (Mt) of contained nitrogen. With 28 percent of this total, China was the largest producer of ammonia. Asia contributed 46 percent of total world ammonia production, and countries of the former U.S.S.R. represented 13 percent. North America also produced 13 percent of the total; Western Europe, 9 percent; the Middle East, 7 percent; Central America and South America, 5 percent; Eastern Europe, 3 percent; and Africa and Oceania

  3. Commercial Nitrogen Fertilizer Purchased

    Data.gov (United States)

    U.S. Environmental Protection Agency — Amounts of fertilizer nitrogen (N) purchased by states in individual years 2003, 2005, 2007, 2009 and 2011, and the % change in average amounts purchased per year...

  4. Integration of PCR-Sequencing Analysis with Multiplex Ligation-Dependent Probe Amplification for Diagnosis of Hereditary Fructose Intolerance.

    Science.gov (United States)

    Ferri, Lorenzo; Caciotti, Anna; Cavicchi, Catia; Rigoldi, Miriam; Parini, Rossella; Caserta, Marina; Chibbaro, Guido; Gasperini, Serena; Procopio, Elena; Donati, Maria Alice; Guerrini, Renzo; Morrone, Amelia

    2012-01-01

    Mutations in the ALDOB gene impair the activity of the hepatic aldolase B enzyme, causing hereditary fructose intolerance (HFI), an inherited autosomic recessive disease of carbohydrate metabolism, that can result in hypoglycemia, liver and kidney failure, coma, and death. Noninvasive diagnosis is possible by identifying mutant ALDOB alleles in suspected patients. We report the genetic characterization of a cohort of 18 HFI Caucasian patients, based on PCR-sequencing and Multiplex Ligation-dependent Probe Amplification (MLPA), with the identification of two novel genetic lesions: a small duplication c.940_941dupT (p.Trp314fsX22) and a large deletion encompassing the promoter region and exon 1. MLPA and long range-PCR (LR-PCR) also identified the recently reported g.7840_14288del6448 allele with a surprisingly high frequency (11%) within our patients' cohort. The most common p.Ala150Pro (44%), p.Ala175Asp (19%), p.Asn335Lys (8%), and/or the known c.360-363del4 (5%), p.Tyr204X (2.8%), IVS6 -2A>G (2.8%) mutant alleles were identified in 14 patients at a homozygous or compound-heterozygous level. The integration of PCR-sequencing analysis with exon-dosage tools [MLPA and quantitative fluorescent multiplex-PCR (QFM-PCR)] led to the full genotyping of patients within our cohort and to the identification of the new deletion encompassing the promoter region and exon 1.

  5. Long-term outcome and efficacy of endoscopic hemorrhoid ligation for symptomatic internal hemorrhoids

    Institute of Scientific and Technical Information of China (English)

    Ming-Yao Su; Cheng-Tang Chiu; Wei-Pin Lin; Chen-Ming Hsu; Pang-Chi Chen

    2011-01-01

    AIM: To assess the long-term outcome of endoscopic hemorrhoid ligation (EHL) for the treatment of symptomatic internal hemorrhoids. METHODS: A total of 759 consecutive patients (415 males and 344 females) were enrolled. Clinical presentations were rectal bleeding (593 patients) and mucosal prolapse (166 patients). All patients received EHL at outpatient clinics. Hemorrhoid severity was classified by Goligher's grading. The mean follow-up period was 55.4 mo (range, 45-92 mo). RESULTS: The number of band ligations averaged 2.35 in the first session for bleeding and 2.69 for prolapsed patients. Bleeding was controlled in 587 (98.0%) patients, while prolapse was reduced in 137 (82.5%) patients. After treatment, 93 patients experienced anal pain and 48 patients had mild bleeding. Patient subjective satisfaction was 93.6%. Repeat treatment or surgery was performed if symptoms were not relieved in the first session. In the bleeding group, the recurrence rate was 3.7% (22 patients) at 1 year, and 6.6% and 13.0% at 2 and 5 years. In the prolapsed group, the recurrence rate was 3.0%, 9.6% and 16.9% at 1, 2 and 5 years, respectively. CONCLUSION: EHL is an easy and well-tolerated procedure for the treatment of symptomatic internal hemorrhoids, with good long-term results.

  6. Prospective randomized comparison of transumbilical two-port laparoscopic and conventional laparoscopic varicocele ligation

    Science.gov (United States)

    Zhang, Guo-Xi; Yang, Jun; Long, Da-Zhi; Liu, Min; Zou, Xiao-Feng; Yuan, Yuan-Hu; Xiao, Ri-Hai; Xue, Yi-Jun; Zhong, Xin; Liu, Quan-Liang; Liu, Fo-Lin; Jiang, Bo; Xu, Rui-Quan; Xie, Kun-Lin

    2017-01-01

    We have established a novel method named transumbilical two-port laparoscopic varicocele ligation (TTLVL) for varicocele, which is still needed to evaluate. In this study, 90 patients with left idiopathic symptomatic varicoceles of grades II–III according to the Dubin grading system were randomly assigned to TTLVL (n = 45) and conventional laparoscopic varicocele ligation (CLVL) (n = 45). The demographic, intraoperative, postoperative, and follow-up data were recorded and compared between the two groups. All the procedures in the two groups were completed successfully with no intraoperative complications and no conversions to open surgery. No significant difference was found in the operative time, resuming ambulation, bowel recovery, postoperative hospital stay, and postoperative resolution of scrotal pain between the two groups (P > 0.05). However, the postoperative mean visual analog pain scale scores for TTLVL group were all less at 24 h, 48 h, 72 h, and 7 days postoperatively compared to CLVL (P = 0.001, 0.010, 0.006, and 0.027, respectively). The mean patient scar assessment questionnaire score in postoperative month 3 was 29.7 for TTLVL group compared with 32.1 for CLVL group (P < 0.001). There was no testicular atrophy observed in both groups during the follow-up period. The study shows that TTLVL is a safe, feasible, and effective minimally invasive surgical alternative to CLVL for the treatment of varicocele. Compared with CLVL, TTLVL may decrease postoperative pain and improve the cosmetic outcomes. PMID:26732104

  7. Design and validation of DNA libraries for multiplexing proximity ligation assays.

    Science.gov (United States)

    Gobet, Nicolas; Ketterer, Simon; Meier, Matthias

    2014-01-01

    Here, we present an in silico, analytical procedure for designing and testing orthogonal DNA templates for multiplexing of the proximity ligation assay (PLA). PLA is a technology for the detection of protein interactions, post-translational modifications, and protein concentrations. To enable multiplexing of the PLA, the target information of antibodies was encoded within the DNA template of a PLA, where each template comprised four single-stranded DNA molecules. Our DNA design procedure followed the principles of minimizing the free energy of DNA cross-hybridization. To validate the functionality, orthogonality, and efficiency of the constructed template libraries, we developed a high-throughput solid-phase rolling-circle amplification assay and solid-phase PLA on a microfluidic platform. Upon integration on a microfluidic chip, 640 miniaturized pull-down assays for oligonucleotides or antibodies could be performed in parallel together with steps of DNA ligation, isothermal amplification, and detection under controlled microenvironments. From a large computed PLA template library, we randomly selected 10 template sets and tested all DNA combinations for cross-reactivity in the presence and absence of antibodies. By using the microfluidic chip application, we determined rapidly the false-positive rate of the design procedure, which was less than 1%. The combined theoretical and experimental procedure is applicable for high-throughput PLA studies on a microfluidic chip.

  8. Bile duct ligation in mice: induction of inflammatory liver injury and fibrosis by obstructive cholestasis.

    Science.gov (United States)

    Tag, Carmen G; Sauer-Lehnen, Sibille; Weiskirchen, Sabine; Borkham-Kamphorst, Erawan; Tolba, René H; Tacke, Frank; Weiskirchen, Ralf

    2015-02-10

    In most vertebrates, the liver produces bile that is necessary to emulsify absorbed fats and enable the digestion of lipids in the small intestine as well as to excrete bilirubin and other metabolic products. In the liver, the experimental obstruction of the extrahepatic biliary system initiates a complex cascade of pathological events that leads to cholestasis and inflammation resulting in a strong fibrotic reaction originating from the periportal fields. Therefore, surgical ligation of the common bile duct has become the most commonly used model to induce obstructive cholestatic injury in rodents and to study the molecular and cellular events that underlie these pathophysiological mechanisms induced by inappropriate bile flow. In recent years, different surgical techniques have been described that either allow reconnection or reanastomosis after bile duct ligation (BDL), e.g., partial BDL, or other microsurgical methods for specific research questions. However, the most frequently used model is the complete obstruction of the common bile duct that induces a strong fibrotic response after 21 to 28 days. The mortality rate can be high due to infectious complications or technical inaccuracies. Here we provide a detailed surgical procedure for the BDL model in mice that induce a highly reproducible fibrotic response in accordance to the 3R rule for animal welfare postulated by Russel and Burch in 1959.

  9. Rubber band ligation for 750 cases of symptomatic hemorrhoids out of 2200 cases

    Institute of Scientific and Technical Information of China (English)

    Ayman M El Nakeeb; Hisham H Abd Elmoniam; Waiel W Khafagy; Mosaad H Horshed; Ramadan E El Lithy; Mohamed E Farid; Amir A Fikry; Waleed H Omar; Elyamani M Fouda; Tito A El Metwally; Hosam E Ghazy; Sabry A Badr; Mohmed Y Abu Elkhar; Salih M Elawady

    2008-01-01

    AIM: To study the results for the treatment of symptomatic hemorrhoids using rubber band ligation (RBL) method. METHODS: A retrospective study for 750 patients who came to the colorectal unit from June, 1998 to September, 2006, data was retrieved from archived files. RBL was performed using the Mc Gown applicator on an outpatient basis. The patients were asked to return to out-patient clinic for follow up at 2 wk, 1 mo, 6 mo and through telephone call every 6 mo for 2 years). RESULTS: After RBL, 696 patients (92.8%) were cured with no difference in outcome for second or third degree hemorrhoids (P = 0.31). Symptomatic recurrence was detected in 11.04% after 2 years. A total of 52 patients (6.93%) had 77 complications from RBL which required no hospitalization. Complications were pain, rectal bleeding and vaso-vagal symptoms (4.13%, 4.13% and 1.33% of patients, respectively). At 1 mo there were a significant improvement in mean SF-36 scores over baseline in five items, while after 2 years there were improvement in all items over baseline, but not significant. No significant manometeric changes after band ligation. CONCLUSION: RBL is a simple, safe and effective method for treating symptomatic second and third degree hemorrhoids as an out patient procedure with significant improvement in quality of life. RBL doesn't alter ano-rectal functions.

  10. Simultaneous bile duct and portal venous branch ligation in two-stage hepatectomy

    Institute of Scientific and Technical Information of China (English)

    Hiroya Iida; Chiaki Yasui; Tsukasa Aihara; Shinichi Ikuta; Hidenori Yoshie; Naoki Yamanaka

    2011-01-01

    Hepatectomy is an effective surgical treatment for multiple bilobar liver metastases from colon cancer; however, one of the primary obstacles to completing surgical resection for these cases is an insufficient volume of the future remnant liver, which may cause postoperative liver failure. To induce atrophy of the unilateral lobe and hypertrophy of the future remnant liver, procedures to occlude the portal vein have been conventionally used prior to major hepatectomy. We report a case of a 50-year-old woman in whom two-stage hepatectomy was performed in combination with intraoperative ligation of the portal vein and the bile duct of the right hepatic lobe. This procedure was designed to promote the atrophic effect on the right hepatic lobe more effectively than the conventional technique, and to the best of our knowledge, it was used for the first time in the present case. Despite successful induction of liver volume shift as well as the following procedure, the patient died of subsequent liver failure after developing recurrent tumors. We discuss the first case in which simultaneous ligation of the portal vein and the biliary system was successfully applied as part of the first step of two-stage hepatectomy.

  11. Prospective randomized comparison of transumbilical two-port laparoscopic and conventional laparoscopic varicocele ligation

    Directory of Open Access Journals (Sweden)

    Guo-Xi Zhang

    2017-01-01

    Full Text Available We have established a novel method named transumbilical two-port laparoscopic varicocele ligation (TTLVL for varicocele, which is still needed to evaluate. In this study, 90 patients with left idiopathic symptomatic varicoceles of grades II-III according to the Dubin grading system were randomly assigned to TTLVL (n = 45 and conventional laparoscopic varicocele ligation (CLVL (n = 45. The demographic, intraoperative, postoperative, and follow-up data were recorded and compared between the two groups. All the procedures in the two groups were completed successfully with no intraoperative complications and no conversions to open surgery. No significant difference was found in the operative time, resuming ambulation, bowel recovery, postoperative hospital stay, and postoperative resolution of scrotal pain between the two groups (P > 0.05. However, the postoperative mean visual analog pain scale scores for TTLVL group were all less at 24 h, 48 h, 72 h, and 7 days postoperatively compared to CLVL (P = 0.001, 0.010, 0.006, and 0.027, respectively. The mean patient scar assessment questionnaire score in postoperative month 3 was 29.7 for TTLVL group compared with 32.1 for CLVL group (P < 0.001. There was no testicular atrophy observed in both groups during the follow-up period. The study shows that TTLVL is a safe, feasible, and effective minimally invasive surgical alternative to CLVL for the treatment of varicocele. Compared with CLVL, TTLVL may decrease postoperative pain and improve the cosmetic outcomes.

  12. CD28 ligation increases macrophage suppression of T-cell proliferation.

    Science.gov (United States)

    Silberman, Daniel; Bucknum, Amanda; Bartlett, Thomas; Composto, Gabriella; Kozlowski, Megan; Walker, Amanda; Werda, Amy; Cua, Jackelyn; Sharpe, Arlene H; Somerville, John E; Riggs, James E

    2012-07-01

    When compared to spleen or lymph node cells, resident peritoneal cavity cells respond poorly to T-cell activation in vitro. The greater proportional representation of macrophages in this cell source has been shown to actively suppress the T-cell response. Peritoneal macrophages exhibit an immature phenotype (MHC class II(lo), B7(lo)) that reduces their efficacy as antigen-presenting cells. Furthermore, these cells readily express inducible nitric oxide synthase (iNOS), an enzyme that promotes T-cell tolerance by catabolism of the limiting amino acid arginine. Here, we investigate the ability of exogenous T-cell costimulation to recover the peritoneal T-cell response. We show that CD28 ligation failed to recover the peritoneal T-cell response and actually suppressed responses that had been recovered by inhibiting iNOS. As indicated by cytokine ELISpot and neutralizing monoclonal antibody (mAb) treatment, this 'cosuppression' response was due to CD28 ligation increasing the number of interferon (IFN)-γ-secreting cells. Our results illustrate that cellular composition and cytokine milieu influence T-cell costimulation biology.Cellular & Molecular Immunology advance online publication, 23 April 2012; doi:10.1038/cmi.2012.13.

  13. Ligation of the adhesion-GPCR EMR2 regulates human neutrophil function.

    Science.gov (United States)

    Yona, Simon; Lin, Hsi-Hsien; Dri, Pietro; Davies, John Q; Hayhoe, Richard P G; Lewis, Sion M; Heinsbroek, Sigrid E M; Brown, K Alun; Perretti, Mauro; Hamann, Jörg; Treacher, David F; Gordon, Siamon; Stacey, Martin

    2008-03-01

    At present, approximately 150 different members of the adhesion-G protein-coupled receptor (GPCR) family have been identified in metazoans. Surprisingly, very little is known about their function, although they all possess large extracellular domains coupled to a seven-transmembrane domain, suggesting a potential role in cell adhesion and signaling. Here, we demonstrate how the human-restricted adhesion-GPCR, EMR2 (epidermal growth factor-like module-containing mucin-like hormone receptor), regulates neutrophil responses by potentiating the effects of a number of proinflammatory mediators and show that the transmembrane region is critical for adhesion-GPCR function. Using an anti-EMR2 antibody, ligation of EMR2 increases neutrophil adhesion and migration, and augments superoxide production and proteolytic enzyme degranulation. On neutrophil activation, EMR2 is rapidly translocated to membrane ruffles and the leading edge of the cell. Further supporting the role in neutrophil activation, EMR2 expression on circulating neutrophils is significantly increased in patients with systemic inflammation. These data illustrate a definitive function for a human adhesion-GPCR within the innate immune system and suggest an important role in potentiating the inflammatory response. Ligation of the adhesion-GPCR EMR2 regulates human neutrophil function.

  14. Comparison of static friction with self-ligating, modified slot design and conventional brackets

    Directory of Open Access Journals (Sweden)

    Raquel Morais Castro

    2013-07-01

    Full Text Available OBJECTIVE: To compare the static frictional forces generated at the bracket/wire interface of stainless steel brackets with different geometries and angulations, combined with orthodontic wires of different diameters. MATERIAL AND METHODS: The frictional forces were evaluated with three different types of metal brackets: a passive self-ligating (SmartClipTM, 3M/Unitek, Monrovia, USA, with a modified slot design (Mini Uni TwinTM, 3M/Unitek, Monrovia, USA and conventional (Kirium, Abzil, São José do Rio Preto, Brazil. The samples were mounted in a testing device with three different angulations and tested with 0.014" and 0.018" stainless steel wires (American Orthodontics, Sheboygan, USA. The static frictional force was measured using a universal testing machine (DL 500, EMIC®, São José dos Pinhais, Brazil with a crosshead speed of 1 mm/min. Statistical analysis was performed by two-way ANOVA followed by Bonferroni's post hoc test. RESULTS: There was a significant difference (p<0.05 in static friction when the three types of brackets were tested with the same wire size. The wire diameter influenced friction only when the brackets had a 10º angulation (p<0.05. The angulation influenced friction (p<0.05 when the brackets were associated with a 0.018" wire. CONCLUSION: Brackets with a modified slot design showed intermediate static frictional force values between the conventional and self-ligating brackets tested.

  15. Electronic Structure of Ligated CdSe Clusters: Dependence on DFT Methodology

    Energy Technology Data Exchange (ETDEWEB)

    Albert, VV; Ivanov, SA; Tretiak, S; Kilina, SV

    2011-07-07

    Simulations of ligated semiconductor quantum dots (QDs) and their physical properties, such as morphologies, QD-ligand interactions, electronic structures, and optical transitions, are expected to be very sensitive to computational methodology. We utilize Density Functional Theory (DFT) and systematically study how the choice of density functional, atom-localized basis set, and a solvent affects the physical properties of the Cd{sub 33}Se{sub 33} cluster ligated with a trimethyl phosphine oxide ligand. We have found that qualitative performance of all exchange-correlation (XC) functionals is relatively similar in predicting strong QD-ligand binding energy ({approx}1 eV). Additionally, all functionals predict shorter Cd-Se bond lengths on the QD surface than in its core, revealing the nature and degree of QD surface reconstruction. For proper modeling of geometries and QD-ligand interactions, however, augmentation of even a moderately sized basis set with polarization functions (e.g., LANL2DZ* and 6-31G*) is very important. A polar solvent has very significant implications for the ligand binding energy, decreasing it to 0.2-0.5 eV. However, the solvent model has a minor effect on the optoelectronic properties, resulting in persistent blue shifts up to {approx}0.3 eV of the low-energy optical transitions. For obtaining reasonable energy gaps and optical transition energies, hybrid XC functionals augmented by a long-range Hartree-Fock orbital exchange have to be applied.

  16. Peripancreatic artery ligation and artery infusion chemotherapy for advanced pancreatic carcinoma

    Institute of Scientific and Technical Information of China (English)

    纪宗正; 王永向; 陈熹; 吴涛

    2003-01-01

    Objective To develop a new treatment for advanced pancreatic carcinoma. Methods Twenty-nine patients with advanced pancreatic carcinoma (12 patients with liver metastasis at the same time) were randomly divided into two groups. In group A (n=11), patients underwent bilio-enterostomy and/or gastro-enterostomy combined with systemic chemotherapy after surgery. In group B (n=18), patients underwent bilio-enterostomy and/or gastro-enterostomy combined with peripancreatic arterial ligation and arterial infusion regional chemotherapy. Twenty-four patients were followed up for 3-18 months. The palliation of clinical symptoms, changes in carcinoma size by B ultrasound (BUS) and CT scan, survival period and serum carcinoembryonic antigen (CEA) were observed and compared between the two groups. Results Symptoms were alleviated in most patients in group B, and BUS and CT scan showed that tumor volume decreased in group B. The response rate was 66.7% in group B and 18.2% in group A (P0.05). Conclusion Peripancreatic arterial ligation combined with arterial infusion regional chemotherapy is effective against both pancreatic carcinoma and with liver metastases. It can alleviate clinical symptoms, postpone the growth rate of tumor and prolong the survival period.

  17. EVALUATION OF RAT MODEL OF CHRONIC GLAUCOMA BY LIGATING EPISCLERAL VEINS

    Institute of Scientific and Technical Information of China (English)

    ZHONG Yi-sheng; CAI Kang; CHENG Yu; JIAO Qin; LIU Xiao-hong; YAO Hui-ping; ZHOU Xiao-qing

    2009-01-01

    Objective To develop and evaluate the rat model of chronic glaucoma by episcleral veins ligation (EVL). Methods Experimental glaucoma was induced unilaterally in 28 male Sprague-Dawley rats by ligating two episcleral veins. Intraocular pressure (IOP) in rats was measured by a Goldmann applanation tonometer under 3% pentobarbital sodium anesthesia. The optic nerve head and retinal vasculature were assessed by repeated fundus examinations. The amount of optic nerve axons was assessed by Image-Pro Plus image analysis system in a masked fashion. Results IOP without EVL was (19.21±1.23)mmHg, whereas the EVL eyes gained about 1.8-fold higher IOP [(33.96±2.73)mmHg] after EVL immediately (P<0.001). The elevated IOP gradually decreased over time. However, the differences were kept significant up to 8 weeks after EVL. The IOP was reduced to similar levels as contralateral eyes at 12 and 16 weeks after EVL. The glaucomatous optic nerve excavation appeared in EVL eyes at 8 weeks after EVL, and the optic nerve excavation enlarged gradually with the increasing post-operation time. The amount of optic nerve axons also significantly decreased in EVL eyes at 8 weeks after EVL, and the amount of axons decreased gradually with the increasing post-operation time. Conclusion Increase of IOP caused by EVL represents a useful and efficient model of experimental glaucoma in rats.

  18. Dang Gui Bu Xue Tang ameliorates coronary artery ligation-induced myocardial ischemia in rats.

    Science.gov (United States)

    Chunhua, Ma; Hongyan, Long; Weina, Zhu; Xiaoli, He; Yajie, Zhang; Jie, Ruan

    2017-01-28

    Dang The present study was designed to investigate cardioprotective effects of Dang Gui Bu Xue Tang (DGBUT) on coronary artery ligation-induced myocardial ischemia. Myocardial ischemia (MI) model was induced in SD rats by surgical ligation of the left anterior descending coronary artery. ST segment elevation of Electrocardiograph (ECG) infarct size, levels of lactate dehydrogenase (LDH), creatine kinase (CK), glutathione (GSH) and catalase (CAT), catalase (SOD), malondialdehyde (MDA), and inflammatory cytokines and phosphorylation of extracellular signal-regulated kinase (ERK) 1/2, p38, c-Jun NH2 terminal kinases (JNK), nuclear factor (NF)-κBp65, inhibitory kappa B (IκB) α, IκB kinase (IKK) α and IKKβ were evaluated in rats treated with or without DGBUT. DGBUT treatment significantly reduced the elevation of the ST segment of ECG, the myocardial infarct size of MI. The level of LDH, CK and MDA were suppressed, the contents of SOD, GSH and CAT were enhanced with DGBUT. The elevated concentration of inflammatory cytokines tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β) and IL-6 in MI rats were effectively reversed by the DGBUT administration. Also, highly expressed p-JNK, p-ERK, p-p38, p-NF-κBp65, p-IκBα, p-IKKα and p-IKKβ in MI rats were restored respectively by DGBUT treatment. The protective effect of DGBUT against MI injury might be associated with MAPK/NF-кB pathway.

  19. Electrochemical detection of aqueous Ag+ based on Ag+-assisted ligation reaction

    Science.gov (United States)

    Miao, Peng; Han, Kun; Wang, Bidou; Luo, Gangyin; Wang, Peng; Chen, Mingli; Tang, Yuguo

    2015-03-01

    In this work, a novel strategy to fabricate a highly sensitive and selective biosensor for the detection of Ag+ is proposed. Two DNA probes are designed and modified on a gold electrode surface by gold-sulfur chemistry and hybridization. In the presence of Ag+, cytosine-Ag+-cytosine composite forms and facilitates the ligation event on the electrode surface, which can block the release of electrochemical signals labeled on one of the two DNA probes during denaturation process. Ag+ can be sensitively detected with the detection limit of 0.1 nM, which is much lower than the toxicity level defined by U.S. Environmental Protection Agency. This biosensor can easily distinguish Ag+ from other interfering ions and the performances in real water samples are also satisfactory. Moreover, the two DNA probes are designed to contain the recognition sequences of a nicking endonuclease, and the ligated DNA can thus be cleaved at the original site. Therefore, the electrode can be regenerated, which allows the biosensor to be reused for additional tests.

  20. Peptide Conjugation to a Polymer Coating via Native Chemical Ligation of Azlactones for Cell Culture.

    Science.gov (United States)

    Schmitt, Samantha K; Trebatoski, David J; Krutty, John D; Xie, Angela W; Rollins, Benjamin; Murphy, William L; Gopalan, Padma

    2016-03-14

    Conjugation of biomolecules for stable presentation is an essential step toward reliable chemically defined platforms for cell culture studies. In this work, we describe the formation of a stable and site-specific amide bond via the coupling of a cysteine terminated peptide at low concentration to an azlactone containing copolymer coating. A copolymer of polyethylene glycol methyl ether methacrylate-ran-vinyl azlactone-ran-glycidyl methacrylate P(PEGMEMA-r-VDM-r-GMA) was used to form a thin coating (20-30 nm) on silicon and polycarbonate substrates. The formation and stability of coating-peptide bonds for peptides containing free thiols and amines were quantified by X-ray photoelectron spectroscopy (XPS) after exposure to cell culture conditions. Peptides containing a thiol as the only nucleophile coupled via a thioester bond; however, the bond was labile under cell culture conditions and almost all the bound peptides were displaced from the surface over a period of 2 days. Coupling with N-terminal primary amine peptides resulted in the formation of an amide bond with low efficiency (chemical ligation. Through a combination of XPS and cell culture studies, we show that the cysteine terminated peptides undergo a native chemical ligation process at low peptide concentration in aqueous media, short reaction time, and at room temperature resulting in the stable presentation of peptides beyond 2 weeks for cell culture studies.

  1. Sequencing by ligation variation with endonuclease V digestion and deoxyinosine-containing query oligonucleotides

    Directory of Open Access Journals (Sweden)

    Ho Antoine

    2011-12-01

    Full Text Available Abstract Background Sequencing-by-ligation (SBL is one of several next-generation sequencing methods that has been developed for massive sequencing of DNA immobilized on arrayed beads (or other clonal amplicons. SBL has the advantage of being easy to implement and accessible to all because it can be performed with off-the-shelf reagents. However, SBL has the limitation of very short read lengths. Results To overcome the read length limitation, research groups have developed complex library preparation processes, which can be time-consuming, difficult, and result in low complexity libraries. Herein we describe a variation on traditional SBL protocols that extends the number of sequential bases that can be sequenced by using Endonuclease V to nick a query primer, thus leaving a ligatable end extended into the unknown sequence for further SBL cycles. To demonstrate the protocol, we constructed a known DNA sequence and utilized our SBL variation, cyclic SBL (cSBL, to resequence this region. Using our method, we were able to read thirteen contiguous bases in the 3' - 5' direction. Conclusions Combining this read length with sequencing in the 5' - 3' direction would allow a read length of over twenty bases on a single tage. Implementing mate-paired tags and this SBL variation could enable > 95% coverage of the genome.

  2. Comparison of emergency endoscopic variceal ligation plus octride or octride alone for acute esophageal variceal bleeding

    Institute of Scientific and Technical Information of China (English)

    LIU Jin-song; LIU Jun

    2009-01-01

    Background Octride was the main method for the treatment of esophageal variceal bleeding (EVB). The aim of this study was to compare the cost-effect and safety between esophageal variceal ligation (EVL) plus octride and octride alone in acute esophageal bleeding.Methods A total of 101 cirrhotic patients with EVB were involved in this study and received emergency EVL+octride (EVL group) or only octride therapy randomly. The cost, efficacy and safety were analyzed and compared between the two groups.Results Among 51 patients in EVL group, 5 (10%) patients failed. Among 50 patients in the octride treatment group, 13 patients (26%) failed. The difference was significant (P<0.05). The average blood transfusion volume was (2.4±2.2) units in the EVL group and (6.4±3.4) units in the octride treatment group (P <0.05). Hospital stay was (7.4±1.3) days in the EVL group and (11.4±3.3) days in the octride treatment group (P<0.05). The average hospital cost was (10 983±1147) yuan in the EVL group and (13 921 ±2107) yuan in the octride treatment group (P<0.05). Conclusion Emergency endoscopic ligation plus octride is superior to octride alone in the treatment of acute EVB with lower cost and higher efficacy with enough safety.

  3. Risk factors for predicting early variceal rebleeding after endoscopic variceal ligation

    Institute of Scientific and Technical Information of China (English)

    Liang Xu; Feng Ji; Qin-Wei Xu; Mie-Qing Zhang

    2011-01-01

    AIM: To analyze the clinical risk factors for early variceal rebleeding after endoscopic variceal ligation (EVL). METHODS: 342 cirrhotic patients with esophageal varices who received elective EVL to prevent bleeding or rebleeding at our endoscopy center between January 2005 and July 2010. were included in this study. The early rebleeding cases after EVL were confirmed by clinical signs or endoscopy. A case-control study was performed comparing the patients presenting with early rebleeding with those without this complication. RESULTS: The incidence of early rebleeding after EVL was 7.60%, and the morbidity of rebleeding was 26.9%. Stepwise multivariate logistic regression analysis showed that four variables were independent risk factors for early rebleeding: moderate to excessive ascites [odds ratio (OR) 62.83, 95% CI: 9.39-420.56, P 18 s (OR 11.35, 95% CI: 1.93-66.70, P = 0.007). CONCLUSION: The early rebleeding rate after EVL is mainly affected by the volume of ascites, number of rubber bands used to ligate, severity of varices and prolonged PT. Effective measures for prevention and treatment should be adopted before and after EVL.

  4. Nitrogen oxide formation from chemically-bound nitrogen during the combustion of fossil fuels. [Extended Zeldovich reactions

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, R.E.

    1976-06-01

    One of the many problems associated with the firing of fossil fuels is the impact on the ambient levels of nitrogen oxides. Since the use of coals, oils and coal-derived fuels is expected to triple by 1985, it is urgent that the formation of nitrogen oxides from molecular nitrogen and organo-nitrogen species be fully characterized so that emission abatement strategies can be formulated. The thermal fixation of atmospheric nitrogen and the free radical reactions of nitrogenous species are the sources of NO/sub x/. The fixation reactions can be described by the extended Zeldovich mechanism, and techniques such as staged combustion and flue gas recirculation have been employed to reduce combustion temperatures and, hence, thermally formed NO. These techniques have had little effect, however, on the conversion of chemically-bound nitrogen to NO/sub x/. The fate of chemically-bound nitrogen depends upon such factors as the nitrogen content of the fuel and the equivalence ratio and upon the physical processes governing combustion. Research is proposed to establish the kinetic processes involved in the conversion of fuel nitrogen to NO and N/sub 2/ in environments characteristic of fossil fuel combustion and to identify those conditions which favor the reduction of NO to N/sub 2/.

  5. Protein Nitrogen Determination

    Science.gov (United States)

    Nielsen, S. Suzanne

    The protein content of foods can be determined by numerous methods. The Kjeldahl method and the nitrogen combustion (Dumas) method for protein analysis are based on nitrogen determination. Both methods are official for the purposes of nutrition labeling of foods. While the Kjeldahl method has been used widely for over a hundred years, the recent availability of automated instrumentation for the Dumas method in many cases is replacing use of the Kjeldahl method.

  6. The preparation and characterization of Cu(II complexes with N,N’,N”,N’”-tetrakis(2-pyridylmethyl-1,4,8,11-tetraazacyclotetradecane and 2,6-diacetylpyridine bis(semi/thiosemicarbazones

    Directory of Open Access Journals (Sweden)

    GORDANA VUCKOVIC

    2004-03-01

    Full Text Available Two new Cu(II mixed-ligand complexes with octadentate N,N’,N”,N’”-tetrakis(2-pyridylmethyl-1,4,8,11-tetraazacyclotetradecane (tpmc and potentially pentadentate ligands 2,6-diacetylpyridine bis(semicarbazone (DAPsc2 or 2,6-diacetylpyridine bis(thiosemicarbazone (DAPtsc2 were prepared. The general formulas: [Cu4 DAPsc2(tpmc2]ClO48·5CH3COCH3·H2O and [Cu2 DAPtsc2(tpmc](ClO44·7C2H5OH were proposed on the basis of elemental analyses and conductometric measurements. The complexes were characterized by magnetic measurement, electronic absorption and IR spectroscopy. For the dinuclear complex, an exo coordination of Cu(II with four nitrogens from tpmc and m-bonded DAPtsc2 through sulfurs and possibly terminal hydrazinic (azomethine nitrogens is assumed. For the tetranuclear complex, it is supposed that one DAPsc2 bridges two [Cu2 tpmc]4+ units using oxygens and terminal hydrazinic nitrogens as ligators. Finally, some antibacterial activity of the complexes was found.

  7. Transesophageal echocardiography, more than a diagnostic tool: use during surgical ligation of coronary artery fistulae - a case report

    Directory of Open Access Journals (Sweden)

    Chung Ping-Chen

    2012-04-01

    Full Text Available Abstract Coronary artery fistulae (CAF are an infrequent coronary abnormality. Herein, we describe the use of intraoperative transesophageal echocardiography (TEE in the treatment of CAF. A 61 year-old woman presented with chest pain and symptoms consistent with unstable angina. Subsequent coronary angiography revealed the presence of 2 CAF, one extending from the left anterior descending artery to the pulmonary artery (PA and the other extending from the proximal right coronary artery to the PA. Surgical ligation of the CAF without coronary bypass was arranged. Intraoperative TEE was successfully employed to localize the CAF, monitor fistula blood flow and heart wall motion, and confirm successful ligation. The patient recovered without complications. This case highlights the utility of intraoperative TEE during ligation of CAF.

  8. "Bis-Click" Ligation of DNA: Template-Controlled Assembly, Circularisation and Functionalisation with Bifunctional and Trifunctional Azides.

    Science.gov (United States)

    Yang, Haozhe; Seela, Frank

    2017-03-08

    Ligation and circularisation of oligonucleotides containing terminal triple bonds was performed with bifunctional or trifunctional azides. Both reactions are high yielding. Template-assisted bis-click ligation of two individual non-complementary oligonucleotide strands was accomplished to yield heterodimers exclusively. In this context, the template fulfils two functions: it accelerates the ligation reaction and controls product assembly (heterodimer vs. homodimer formation). Intermolecular bis-click circularisation of one oligonucleotide strand took place without template assistance. For construction of oligonucleotides with terminal triple bonds in the nucleobase side chain, 7- or 5-functionalised 7-deaza-dA and dU residues were used. These oligonucleotides are directly accessible by solid-phase synthesis. When trifunctional azides were employed instead of bifunctional linkers, functionalisation of the remaining azido group was performed with small molecules such as 1-ethynyl pyrene, biotin propargyl amide or with ethynylated oligonucleotides. By this means, branched DNA was constructed.

  9. Brucella, nitrogen and virulence.

    Science.gov (United States)

    Ronneau, Severin; Moussa, Simon; Barbier, Thibault; Conde-Álvarez, Raquel; Zuniga-Ripa, Amaia; Moriyon, Ignacio; Letesson, Jean-Jacques

    2016-08-01

    The brucellae are α-Proteobacteria causing brucellosis, an important zoonosis. Although multiplying in endoplasmic reticulum-derived vacuoles, they cause no cell death, suggesting subtle but efficient use of host resources. Brucellae are amino-acid prototrophs able to grow with ammonium or use glutamate as the sole carbon-nitrogen source in vitro. They contain more than twice amino acid/peptide/polyamine uptake genes than the amino-acid auxotroph Legionella pneumophila, which multiplies in a similar vacuole, suggesting a different nutritional strategy. During these two last decades, many mutants of key actors in nitrogen metabolism (transporters, enzymes, regulators, etc.) have been described to be essential for full virulence of brucellae. Here, we review the genomic and experimental data on Brucella nitrogen metabolism and its connection with virulence. An analysis of various aspects of this metabolism (transport, assimilation, biosynthesis, catabolism, respiration and regulation) has highlighted differences and similarities in nitrogen metabolism with other α-Proteobacteria. Together, these data suggest that, during their intracellular life cycle, the brucellae use various nitrogen sources for biosynthesis, catabolism and respiration following a strategy that requires prototrophy and a tight regulation of nitrogen use.

  10. Research on nitrogen physical adsorption method and mercury intrusion method used for characterization of FCC catalyst pore size distribution%氮气物理吸附法和压汞法表征FCC催化剂孔径分布研究

    Institute of Scientific and Technical Information of China (English)

    曹庚振; 王林; 张艳惠; 杨周侠; 杨一青; 王宝杰

    2015-01-01

    Nitrogen physical adsorption method and mercury intrusion method were used respectively to investigate pore size distribution of different types of FCC catalysts before and after they were aged. The result showed,the nitrogen physical adsorption method using BJH model can characterize the pores of 2~100 nm,but its calculation is not accurate for pores larger than 100 nm. The mercury intrusion method using Wasburn formula can cover the shortage of nitrogen physical adsorption method in term of large bore size analysis,and the combination of the two methods can effectively characterize the middle and large bore size distribution of catalysts.%分别采用氮气物理吸附法和压汞法考察了同类型的FCC催化剂老化前后的孔径分布情况。结果表明,氮气物理吸附法应用BJH模型可以表征2~100 nm的孔,但对大于100 nm的孔计算不准确。压汞法使用Wasburn公式能弥补氮气吸附法在大孔孔径分析方面的不足,两者结合可以有效表征催化剂的中大孔孔径分布。

  11. Mandibular arch orthodontic treatment stability using passive self-ligating and conventional systems in adults: A randomized controlled trial

    Science.gov (United States)

    Wey, Mang Chek; Othman, Siti Adibah

    2017-01-01

    Objective This randomized controlled trial aimed to compare the stability of mandibular arch orthodontic treatment outcomes between passive self-ligating and conventional systems during 6 months of retention. Methods Fortyseven orthodontic patients with mild to moderate crowding malocclusions not requiring extraction were recruited based on inclusion criteria. Patients (mean age 21.58 ± 2.94 years) were randomized into two groups to receive either passive self-ligating (Damon® 3MX, n = 23) or conventional system (Gemini MBT, n = 24) orthodontic treatment. Direct measurements of the final sample comprising 20 study models per group were performed using a digital caliper at the debonding stage, and 1 month, 3 months, and 6 months after debonding. Paired t-test, independent t-test, and non-parametric test were used for statistical analysis. Results A significant increase (p < 0.01) in incisor irregularity was observed in both self-ligating and conventional system groups. A significant reduction (p < 0.01) in second interpremolar width was observed in both groups. Mandibular arch length decreased significantly (p = 0.001) in the conventional system group but not in the self-ligating system group. A similar pattern of stability was observed for intercanine width, first interpremolar width, intermolar width, and arch depth throughout the 6-month retention period after debonding. Comparison of incisor irregularity and arch dimension changes between self-ligating system and conventional system groups during the 6 months were non-significant. Conclusions The stability of treatment outcomes for mild to moderate crowding malocclusions was similar between the self-ligating system and conventional system during the first 6 months of retention. PMID:28127535

  12. Precise Quantitation of MicroRNA in a Single Cell with Droplet Digital PCR Based on Ligation Reaction.

    Science.gov (United States)

    Tian, Hui; Sun, Yuanyuan; Liu, Chenghui; Duan, Xinrui; Tang, Wei; Li, Zhengping

    2016-12-06

    MicroRNA (miRNA) analysis in a single cell is extremely important because it allows deep understanding of the exact correlation between the miRNAs and cell functions. Herein, we wish to report a highly sensitive and precisely quantitative assay for miRNA detection based on ligation-based droplet digital polymerase chain reaction (ddPCR), which permits the quantitation of miRNA in a single cell. In this ligation-based ddPCR assay, two target-specific oligonucleotide probes can be simply designed to be complementary to the half-sequence of the target miRNA, respectively, which avoids the sophisticated design of reverse transcription and provides high specificity to discriminate a single-base difference among miRNAs with simple operations. After the miRNA-templated ligation, the ddPCR partitions individual ligated products into a water-in-oil droplet and digitally counts the fluorescence-positive and negative droplets after PCR amplification for quantification of the target molecules, which possesses the power of precise quantitation and robustness to variation in PCR efficiency. By integrating the advantages of the precise quantification of ddPCR and the simplicity of the ligation-based PCR, the proposed method can sensitively measure let-7a miRNA with a detection limit of 20 aM (12 copies per microliter), and even a single-base difference can be discriminated in let-7 family members. More importantly, due to its high selectivity and sensitivity, the proposed method can achieve precise quantitation of miRNAs in single-cell lysate. Therefore, the ligation-based ddPCR assay may serve as a useful tool to exactly reveal the miRNAs' actions in a single cell, which is of great importance for the study of miRNAs' biofunction as well as for the related biomedical studies.

  13. Protective effect of ginger oil on aspirin and pylorus ligation-induced gastric ulcer model in rats

    Directory of Open Access Journals (Sweden)

    Khushtar M

    2009-01-01

    Full Text Available The present investigation was performed in aspirin and pylorus ligation-induced ulcer model in Wistar rats, in which ability of ginger oil to provide gastric protection was studied at two different doses, 0.5 and 1 g/kg po. Gastric protection was evaluated by measuring the ulcer index, serum λ- GTP levels, total acidity of gastric juice and gastric wall mucus thickness. The results obtained in the present study indicated that ginger oil has a protective action against gastric ulcers induced by aspirin plus pylorus ligation in Wistar rats.

  14. Chemical syntheses of inhibitory substrates of the RNA-RNA ligation reaction catalyzed by the hairpin ribozyme.

    Science.gov (United States)

    Massey, Archna P; Sigurdsson, Snorri Th

    2004-01-01

    The chemical syntheses of RNA oligomers containing modifications on the 5'-carbon of the 5'-terminal nucleoside for crystallographic and mechanistic studies of the hairpin ribozyme are reported. Phosphoramidites 4 and 8 were prepared and used in solid phase syntheses of RNA oligomers containing the sequence 5'-N'UCCUCUCC, where N' indicates either 5'-chloro-5'-deoxyguanosine or 5'-amino-5'-deoxyguanosine, respectively. A ribozyme ligation assay with the 5'-chloro- and 5'-amino-modified RNA oligomers demonstrated their inhibition of the hairpin-catalyzed RNA-RNA ligation reaction.

  15. Increased secretion of insulin and proliferation of islet {beta}-cells in rats with mesenteric lymph duct ligation

    Energy Technology Data Exchange (ETDEWEB)

    Nagino, Ko; Yokozawa, Junji; Sasaki, Yu; Matsuda, Akiko; Takeda, Hiroaki [Department of Gastroenterology, Faculty of Medicine, Yamagata University, Yamagata 990-9585 (Japan); Kawata, Sumio, E-mail: Sumio_Kawata@pref.hyogo.lg.jp [Department of Gastroenterology, Faculty of Medicine, Yamagata University, Yamagata 990-9585 (Japan); Hyogo Prefectural Nishinomiya Hospital, 13-9 Rokutanji-cho, Nishinomiya 662-0918 (Japan)

    2012-08-24

    Highlights: Black-Right-Pointing-Pointer Insulin secretion was increased during the OGTT or IVGTT in mesenteric lymph duct-ligated rats. Black-Right-Pointing-Pointer Proliferation of islet {beta}-cells was upregulated in lymph duct-ligated rats. Black-Right-Pointing-Pointer Mesenteric lymph duct flow has a role in glucose metabolism. -- Abstract: Background and aims: It has been suggested that intestinal lymph flow plays an important role in insulin secretion and glucose metabolism after meals. In this study, we investigated the influence of ligation of the mesenteric lymph duct on glucose metabolism and islet {beta}-cells in rats. Methods: Male Sprague-Dawley rats (10 weeks old) were divided into two groups: one underwent ligation of the mesenteric lymph duct above the cistern (ligation group), and the other underwent a sham operation (sham group). After 1 and 2 weeks, fasting plasma concentrations of glucose, insulin, triglyceride, glucose-dependent insulinotropic polypeptide (GIP), and the active form of glucagon-like peptide-1 (GLP-1) were measured. At 2 weeks after the operation, the oral glucose tolerance test (OGTT) and intravenous glucose tolerance test (IVGTT) were performed. After the rats had been sacrificed, the insulin content of the pancreas was measured and the proliferation of {beta}-cells was assessed immunohistochemically using antibodies against insulin and Ki-67. Results: During the OGTT, the ligation group showed a significant decrease in the plasma glucose concentration at 120 min (p < 0.05) and a significant increase in the plasma insulin concentration by more than 2-fold at 15 min (p < 0.01). On the other hand, the plasma GIP concentration was significantly decreased at 60 min (p < 0.01) in the ligated group, while the active form of GLP-1 showed a significantly higher level at 90 min (1.7-fold; p < 0.05) and 120 min (2.5-fold; p < 0.01). During the IVGTT, the plasma insulin concentration in the ligation group was significantly higher at 2

  16. Detection of ligation products of DNA linkers with 5'-OH ends by denaturing PAGE silver stain.

    Directory of Open Access Journals (Sweden)

    Feng Gao

    Full Text Available To explore if DNA linkers with 5'-hydroxyl (OH ends could be joined by commercial T4 and E. coli DNA ligase, these linkers were synthesized by using the solid-phase phosphoramidite method and joined by using commercial T4 and E. coli DNA ligases. The ligation products were detected by using denaturing PAGE silver stain and PCR method. About 0.5-1% of linkers A-B and E-F, and 0.13-0.5% of linkers C-D could be joined by T4 DNA ligases. About 0.25-0.77% of linkers A-B and E-F, and 0.06-0.39% of linkers C-D could be joined by E. coli DNA ligases. A 1-base deletion (-G and a 5-base deletion (-GGAGC could be found at the ligation junctions of the linkers. But about 80% of the ligation products purified with a PCR product purification kit did not contain these base deletions, meaning that some linkers had been correctly joined by T4 and E. coli DNA ligases. In addition, about 0.025-0.1% of oligo 11 could be phosphorylated by commercial T4 DNA ligase. The phosphorylation products could be increased when the phosphorylation reaction was extended from 1 hr to 2 hrs. We speculated that perhaps the linkers with 5'-OH ends could be joined by T4 or E. coli DNA ligase in 2 different manners: (i about 0.025-0.1% of linkers could be phosphorylated by commercial T4 DNA ligase, and then these phosphorylated linkers could be joined to the 3'-OH ends of other linkers; and (ii the linkers could delete one or more nucleotide(s at their 5'-ends and thereby generated some 5'-phosphate ends, and then these 5'-phosphate ends could be joined to the 3'-OH ends of other linkers at a low efficiency. Our findings may probably indicate that some DNA nicks with 5'-OH ends can be joined by commercial T4 or E. coli DNA ligase even in the absence of PNK.

  17. Plaque retention by self-ligating vs elastomeric orthodontic brackets: quantitative comparison of oral bacteria and detection with adenosine triphosphate-driven bioluminescence.

    NARCIS (Netherlands)

    Pellegrini, P.; Sauerwein, R.W.; Finlayson, T.; McLeod, J.; Covell, D.A.; Maier, T.; Machida, C.A.

    2009-01-01

    INTRODUCTION: Enamel decalcification is a common problem in orthodontics. The objectives of this randomized clinical study were to enumerate and compare plaque bacteria surrounding 2 bracket types, self-ligating (SL) vs elastomeric ligating (E), and to determine whether adenosine triphosphate (ATP)-

  18. Nitrogen starvation affects bacterial adhesion to soil

    Science.gov (United States)

    Borges, Maria Tereza; Nascimento, Antônio Galvão; Rocha, Ulisses Nunes; Tótola, Marcos Rogério

    2008-01-01

    One of the main factors limiting the bioremediation of subsoil environments based on bioaugmentation is the transport of selected microorganisms to the contaminated zones. The characterization of the physiological responses of the inoculated microorganisms to starvation, especially the evaluation of characteristics that affect the adhesion of the cells to soil particles, is fundamental to anticipate the success or failure of bioaugmentation. The objective of this study was to investigate the effect of nitrogen starvation on cell surface hydrophobicity and cell adhesion to soil particles by bacterial strains previously characterized as able to use benzene, toluene or xilenes as carbon and energy sources. The strains LBBMA 18-T (non-identified), Arthrobacter aurescens LBBMA 98, Arthrobacter oxydans LBBMA 201, and Klebsiella sp. LBBMA 204–1 were used in the experiments. Cultivation of the cells in nitrogen-deficient medium caused a significant reduction of the adhesion to soil particles by all the four strains. Nitrogen starvation also reduced significantly the strength of cell adhesion to the soil particles, except for Klebsiella sp. LBBMA 204–1. Two of the four strains showed significant reduction in cell surface hydrophobicity. It is inferred that the efficiency of bacterial transport through soils might be potentially increased by nitrogen starvation. PMID:24031246

  19. In-vivo assessment of DNA ligation efficiency and fidelity in cells from patients with Fanconi's anemia and other cancer-prone hereditary disorders.

    Science.gov (United States)

    Rünger, T M; Sobotta, P; Dekant, B; Möller, K; Bauer, C; Kraemer, K H

    1993-04-01

    We developed a host cell DNA ligation assay, in which we transfected linearized plasmid pZ189 into human lymphoblasts or fibroblasts in order to assess the efficiency and accuracy of DNA ligation within these host cells. We used cell lines from patients with Fanconi's anemia and other chromosome breakage or instability syndromes (Bloom's syndrome, ataxia telangiectasia, Werner's syndrome). With the Fanconi's anemia lymphoblast line GM8010 we did not find a reduced, but a slightly hypermutable DNA ligation. Mutation analysis revealed a unique 7.9-12.5-fold increase in insertions or complex mutations. With cells from the other chromosome breakage/instability syndromes we also found a hypermutable and/or reduced DNA ligation. An impaired DNA ligation might be a common molecular mechanism of genetic instability in these disorders.

  20. Synthesis of spin-labeled riboswitch RNAs using convertible nucleosides and DNA-catalyzed RNA ligation.

    Science.gov (United States)

    Büttner, Lea; Seikowski, Jan; Wawrzyniak, Katarzyna; Ochmann, Anne; Höbartner, Claudia

    2013-10-15

    Chemically stable nitroxide radicals that can be monitored by electron paramagnetic resonance (EPR) spectroscopy can provide information on structural and dynamic properties of functional RNA such as riboswitches. The convertible nucleoside approach is used to install 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) and 2,2,5,5-tetramethylpyrrolidin-1-oxyl (proxyl) labels at the exocyclic N(4)-amino group of cytidine and 2'-O-methylcytidine nucleotides in RNA. To obtain site-specifically labeled long riboswitch RNAs beyond the limit of solid-phase synthesis, we report the ligation of spin-labeled RNA using an in vitro selected deoxyribozyme as catalyst, and demonstrate the synthesis of TEMPO-labeled 53 nt SAM-III and 118 nt SAM-I riboswitch domains (SAM=S-adenosylmethionine).

  1. Effect of Tridax procumbens (Linn.) on bile duct ligation-induced liver fibrosis in rats.

    Science.gov (United States)

    Joshi, P P; Patil, S D; Silawat, N; Deshmukh, P T

    2011-12-01

    The present study was undertaken to clarify whether methanolic extract of Tridax procumbens prevents liver fibrosis in rat. The hepatic fibrosis was induced by 28 days of bile duct ligation in rats. The 4-week treatment with Tridex procumbens reduced the serum aspartate aminotransferase (U L⁻¹), glutamate pyruvate transaminase (U L⁻¹), alkaline phosphatase (IU L⁻¹), lactate dehydrogenase (IU L⁻¹), total bilirubin (mg dL⁻¹), direct bilirubin (mg dL⁻¹) and hydroxyproline (mg gm⁻¹) content in liver and improved the histological appearance of liver section. The results of this study led us to conclude that T. procumbens can reduce the degree of hepatocellular damage and may become antifibrotic agent for liver fibrosis.

  2. Effect of glutamine synthetase inhibition on brain and interorgan ammonia metabolism in bile duct ligated rats

    DEFF Research Database (Denmark)

    Fries, Andreas W; Dadsetan, Sherry; Keiding, Susanne

    2014-01-01

    of healthy rats, inhibition of GS by methionine sulfoximine (MSO) reduced glutamine synthesis and increased alanine synthesis. Here, we investigate effects of MSO on brain and interorgan ammonia metabolism in sham and bile duct ligated (BDL) rats. Concentrations of glutamine, glutamate, alanine......Ammonia has a key role in the development of hepatic encephalopathy (HE). In the brain, glutamine synthetase (GS) rapidly converts blood-borne ammonia into glutamine which in high concentrations may cause mitochondrial dysfunction and osmolytic brain edema. In astrocyte-neuron cocultures and brains...... but only in brain was an increased incorporation of (15)N-ammonia into alanine observed. Liver and kidney were important for metabolizing blood-borne ammonia....

  3. Detection of reverse transcriptase termination sites using cDNA ligation and massive parallel sequencing

    DEFF Research Database (Denmark)

    Kielpinski, Lukasz J; Boyd, Mette; Sandelin, Albin;

    2013-01-01

    of these methods can be increased by applying massive parallel sequencing technologies.Here, we describe a versatile method for detection of reverse transcriptase termination sites based on ligation of an adapter to the 3' end of cDNA with bacteriophage TS2126 RNA ligase (CircLigase™). In the following PCR......Detection of reverse transcriptase termination sites is important in many different applications, such as structural probing of RNAs, rapid amplification of cDNA 5' ends (5' RACE), cap analysis of gene expression, and detection of RNA modifications and protein-RNA cross-links. The throughput...... that do not require formal bioinformatics training. As an example, we apply the method to detection of transcription start sites in mouse liver cells....

  4. Rapid construction of mycobacterial mutagenesis vectors using ligation-independent cloning

    Science.gov (United States)

    Balhana, Ricardo; Stoker, Neil G.; Sikder, Mahmudul Hasan; Chauviac, Francois-Xavier; Kendall, Sharon L.

    2010-01-01

    Targeted mutagenesis is one of the major tools for determining the function of a given gene and its involvement in bacterial pathogenesis. In mycobacteria, gene deletion is often accomplished by using allelic exchange techniques that commonly utilise a suicide delivery vector. We have adapted a widely-used suicide delivery vector (p1NIL) for cloning two flanking regions of a gene using ligation independent cloning (LIC). The pNILRB plasmid series produced allow a faster, more efficient and less laborious cloning procedure. In this paper we describe the making of pNILRB5, a modified version of p1NIL that contains two pairs of LIC sites flanking either a sacB or a lacZ gene. We demonstrate the success of this technique by generating 3 mycobacterial mutant strains. These vectors will contribute to more high-throughput methods of mutagenesis. PMID:20650290

  5. [Experimental results after acute and chronic ligation of bile duct (author's transl)].

    Science.gov (United States)

    Kirchner, R; Hartung, H; Trendelenburg, C

    1980-08-01

    The bile duct was ligated in 14 bastard dogs. Bilirubine, alcaline phosphatase, GOT, GPT, GLDH, and gamma GT were measured pre- and postoperatively. On the 8th postoperative day stenosis of the choledochus was eliminated using a patch plasty for dilatation in 7 dogs, whereas the occlusion remained in the other 7 dogs. Laboratory and histological results were characteristic for cholestasis 8 days after occlusion; these changes disappeared within 4 weeks after patch plastic surgery. In the controls these parameters normalized as well within 8 weeks, in spite of the persisting occlusion. These results show, that pathological changes after short term cholestasis are fully reversible; they demonstrate as well, that there are compensatory mechanisms operating in dogs with permanent occlusion of the bile duct.

  6. Laser brackets debonding: Tm:YAP and ClarityTM SL self-ligating appliance system

    Science.gov (United States)

    Dostálová, Tatjana; Jelínková, Helena; Šulc, Jan; Koranda, Petr; Němec, Michal; Jelínek, Michal; Fibrich, Martin; Michalik, Pavel; Miyagi, Mitsunobu

    2010-02-01

    The study demonstrates the possibility of using Tm:YAP laser radiation for the removing ceramic brackets. The amount of enamel loss and residual resin on teeth has been evaluated. A diode-pumped Tm:YAP microchip laser generating at wavelength 1.9 μm was used for the debonding process. The transmission and absorption measurement of the basic elements - bracket, adhesive resin, and enamel was analyzed to explain the source of the heat and bracket debonding. Quantitative measurements are made for visualizing enamel surface before and after a self-ligating bonding technique. Temperature rise observation during the debonding procedure - from 0.5 to 2 W power - has improved the accuracy of assessment. The results were evaluated by CCD camera and scanning electron microscope. From the measurements it is possible to conclude that continuously running small diode pumped Tm:YAP microchip laser having output power 1W can remove the ceramic bracket without enamel iatrogenic damage.

  7. Application of a pig ligated intestinal loop model for early Lawsonia intracellularis infection

    DEFF Research Database (Denmark)

    Boutrup, Torsten Snogdal; Schauser, Kirsten; Agerholm, Jørgen S

    2010-01-01

    -enterocyte interactions. Methods A ligated small intestinal loop model using three different L. intracellularis inocula was applied to 10- 11-week-old pigs. The inocula were 1) wild type bacteria derived from overnight incubation of L. intracellularis bacteria from spontaneous disease, 2) crude vaccine bacteria......Background Porcine proliferative enteropathy in pigs is caused by the obligate, intracellular bacterium Lawsonia intracellularis. In vitro studies have shown close bacterium-cell interaction followed by cellular uptake of the bacterium within 3 h post inoculation (PI). However, knowledge...... (Enterisol® Ileitis Vet), and 3) vaccine bacteria propagated in cell culture. The bacteria-enterocyte interaction was visualised using immunohistochemistry on specimens derived 1, 3 and 6 h PI respectively. Results Although at a low level, close contact between bacteria and the enterocyte brush border...

  8. Testing the feasibility of DNA typing for human identification by PCR and an oligonucleotide ligation assay

    Energy Technology Data Exchange (ETDEWEB)

    Delahunty, C.; Ankener, W.; Deng, Qiang [Univ. of Washington, Seattle, WA (United States)] [and others

    1996-06-01

    The use of DNA typing in human genome analysis is increasing and finding widespread application in the area of forensic and paternity testing. In this report, we explore the feasibility of typing single nucleotide polymorphisms (SNPs) by using a semiautomated method for analyzing human DNA samples. In this approach, PCR is used to amplify segments of human DNA containing a common SNP. Allelic nucleotides in the amplified product are then typed by a calorimetric implementation of the oligonucleotide ligation assay (OLA). The results of the combined assay, PCR/OLA, are read directly by a spectrophotometer; the absorbances are compiled and the genotypes are automatically determined. A panel of 20 markers has been developed for DNA typing and has been tested using a sample panel from the CEPH pedigrees (CEPH parents). The results of this typing, as well as the potential to apply this method to larger populations, are discussed. 62 refs., 2 figs., 4 tabs.

  9. Photoclick chemistry: a fluorogenic light-triggered in vivo ligation reaction.

    Science.gov (United States)

    Ramil, Carlo P; Lin, Qing

    2014-08-01

    The ability to use chemical reactivity to monitor and control biomolecular processes with a spatial and temporal precision motivated the development of light-triggered in vivo chemistries. To this end, the photoinduced tetrazole-alkene cycloaddition, also termed 'photoclick chemistry' offers a very rapid chemical ligation platform for the manipulation of biomolecules and matrices in vivo. Here we outline the recent developments in the optimization of this chemistry, ranging from the search for substrates that offer two-photon photoactivatability, superior reaction kinetics, and/or genetic encodability, to the study of the reaction mechanism. The applications of the photoclick chemistry in protein labeling in vitro and in vivo as well as in preparing 'smart' hydrogels for 3D cell culture are highlighted.

  10. Highly specific and sensitive electrochemical genotyping via gap ligation reaction and surface hybridization detection.

    Science.gov (United States)

    Huang, Yong; Zhang, Yan-Li; Xu, Xiangmin; Jiang, Jian-Hui; Shen, Guo-Li; Yu, Ru-Qin

    2009-02-25

    This paper developed a novel electrochemical genotyping strategy based on gap ligation reaction with surface hybridization detection. This strategy utilized homogeneous enzymatic reactions to generate molecular beacon-structured allele-specific products that could be cooperatively annealed to capture probes stably immobilized on the surface via disulfide anchors, thus allowing ultrasensitive surface hybridization detection of the allele-specific products through redox tags in close proximity to the electrode. Such a unique biphasic architecture provided a universal methodology for incorporating enzymatic discrimination reactions in electrochemical genotyping with desirable reproducibility, high efficiency and no interferences from interficial steric hindrance. The developed technique was demonstrated to show intrinsic high sensitivity for direct genomic analysis, and excellent specificity with discriminativity of single nucleotide variations.

  11. Carbon and nitrogen isotopic signatures and nitrogen profile to identify adulteration in organic fertilizers.

    Science.gov (United States)

    Verenitch, Sergei; Mazumder, Asit

    2012-08-29

    Recently it has been shown that stable isotopes of nitrogen can be used to discriminate between organic and synthetic fertilizers, but the robustness of the approach is questionable. This work developed a comprehensive method that is far more robust in identifying an adulteration of organic nitrogen fertilizers. Organic fertilizers of various types (manures, composts, blood meal, bone meal, fish meal, products of poultry and plant productions, molasses and seaweed based, and others) available on the North American market were analyzed to reveal the most sensitive criteria as well as their quantitative ranges, which can be used in their authentication. Organic nitrogen fertilizers of known origins with a wide δ(15)N range between -0.55 and 28.85‰ (n = 1258) were characterized for C and N content, δ(13)C, δ(15)N, viscosity, pH, and nitrogen profile (urea, ammonia, organic N, water insoluble N, and NO3). A statistically significant data set of characterized unique organic nitrogen fertilizers (n = 335) of various known origins has been assembled. Deliberately adulterated samples of different types of organic fertilizers mixed with synthetic fertilizers at a wide range of proportions have been used to develop the quantitative critical characteristics of organic fertilizers as the key indicators of their adulteration. Statistical analysis based on the discriminant functions of the quantitative critical characteristics of organic nitrogen fertilizers from 14 different source materials revealed a very high average rate of correct classification. The developed methodology has been successfully used as a source identification tool for numerous commercial nitrogen fertilizers available on the North American market.

  12. Mesenteric lymph duct ligation improves survival in a lethal shock model.

    Science.gov (United States)

    Badami, Chirag D; Senthil, Maheswari; Caputo, Francis J; Rupani, Bobby J; Doucet, Danielle; Pisarenko, Vadim; Xu, Da-Zhong; Lu, Qi; Feinman, Rena; Deitch, Edwin A

    2008-12-01

    The goal of this study was to test the hypothesis that factors released from the gut and carried in the mesenteric lymph contribute to mortality in a lethal gut I/R model. To test this hypothesis, a lethal splanchnic artery occlusion (SAO) shock model was used in male Sprague-Dawley rats. In the first set of experiments, ligation of the mesenteric lymph duct (LDL), which prevents gut-derived factors carried in the intestinal lymphatics from reaching the systemic circulation, significantly improved 24-h survival after a 20-min SAO insult (0% vs. 60% survival; P < 0.05). This increase in survival in the LDL-treated rats was associated with a blunted hypotensive response. Because increased iNOS-induced NO levels have been implicated in SAO-induced shock, we measured plasma nitrite/nitrate levels and liver iNOS protein levels in a second group of animals. Ligation of the mesenteric lymph duct significantly abrogated the SAO-induced increase in plasma nitrite/nitrate levels and the induction of hepatic iNOS (P < 0.05). In an additional series of studies, we documented that LDL increased not only 24-h but also long-term 7-day survival. During the course of these studies, we made the unexpected finding that Sprague-Dawley rats from different animal vendors had differential resistance to SAO, and that the time of the year that the experiments were carried out also influenced the results. Nonetheless, in conclusion, these studies support the hypothesis that factors carried in the mesenteric lymph significantly contribute to the development of irreversible shock after SAO.

  13. Dose-related effects of dexamethasone on liver damage due to bile duct ligation in rats

    Institute of Scientific and Technical Information of China (English)

    Halil Eken; Hayrettin Ozturk; Hulya Ozturk; Huseyin Buyukbayram

    2006-01-01

    AIM: To evaluate the effects of dexamethasone on liver damage in rats with bile duct ligation. METHODS: A total of 40 male Sprague-Dawley rats,weighing 165-205 g, were used in this study. Group 1 (sham-control, n = 10) rats underwent laparotomy alone and the bile duct was just dissected from the surrounding tissue. Group 2 rats (untreated, n = 10)were subjected to bile duct ligation (BDL) and no drug was applied. Group 3 rats (low-dose dexa, n = 10)received a daily dose of dexamethasone by orogastric tube for 14 d after BDL. Group 4 rats (high-dose dexa,n = 10) received a daily dose of dexamethasone by orogastric tube for 14 d after BDL. At the end of the twoweek period, biochemical and histological evaluations were processed.RESULTS: The mean serum bilirubin and liver enzyme levels significantly decreased, and superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSHPx) values were significantly increased in low-dose dexa and high-dose dexa groups when compared to the untreated group. The histopathological score was significantly less in the low-dose and high-dose dexa groups compared to the untreated rats. In the low-dose dexa group, moderate liver damage was seen, while mild liver damage was observed in the high-dose dexa group.CONCLUSION: Corticosteroids reduced liver damage produced by bile duct obstruction. However, the histopathological score was not significantly lower in the high-dose corticosteroid group as compared to the lowdose group. Thus, low-dose corticosteroid provides a significant reduction of liver damage without increased side effects, while high dose is associated not with lower fibrosis but with increased side effects.

  14. The ligational behavior of an isatinic quinolyl hydrazone towards copper(II- ions

    Directory of Open Access Journals (Sweden)

    Mousa Marwa A

    2011-04-01

    Full Text Available Abstract Background The importance of the isatinic quinolyl hydrazones arises from incorporating the quinoline ring with the indole ring. Quinoline ring has therapeutic and biological activities whereas, the indole ring occurs in Jasmine flowers and Orange blossoms. As a ligand, the isatin moiety is potentially ambidentate and can coordinate the metal ions either through its lactam or lactim forms. In a previous study, the ligational behavior of a phenolic quinolyl hydrazone towards copper(II- ions has been studied. As continuation of our interest, the present study is planned to check the ligational behavior of an isatinic quinolyl hydrazone. Results New homo- and heteroleptic copper(II- complexes were obtained from the reaction of an isatinic quinolyl hydrazone (HL with several copper(II- salts viz. Clˉ, Brˉ, NO3ˉ, ClO4-, SO42- and AcO-. The obtained complexes have Oh, Td and D4h- symmetry and fulfill the strong coordinating ability of Clˉ, Brˉ, NO3ˉ and SO42- anions. Depending on the type of the anion, the ligand coordinates the copper(II- ions either through its lactam (NO3ˉ and ClO4- or lactim (the others forms. Conclusion The effect of anion for the same metal ion is obvious from either the geometry of the isolated complexes (Oh, Td and D4h or the various modes of bonding. Also, the obtained complexes fulfill the strong coordinating ability of Clˉ, Brˉ, NO3ˉ and SO42- anions in consistency with the donor ability of the anions. In case of copper(II- acetate, a unique homoleptic complex (5 was obtained in which the AcO- anion acts as a base enough to quantitatively deprotonate the hydrazone. The isatinic hydrazone uses its lactim form in most complexes.

  15. Ultrasound assisted great saphenous vein ligation and division: an office procedure

    Directory of Open Access Journals (Sweden)

    Stefano Ricci

    2014-10-01

    Full Text Available The aim of this proof of concept study is to describe an ultrasound (US assisted simplified surgical procedure for pre-terminal great saphenous vein (GSV high ligation/division avoiding groin dissection and tributary interruption, in an office setting, in association to varices phlebectomy and saphenous vein foam occlusion treatment. Inclusion criteria: primary GSV reflux due to terminal valve, vein diameter >6 mm. By ultrasonography in standing position, the point GSV passing over the adductor longus muscle (about 3 cm from the junction is identified. This E (easy point, relatively superficial, free from tributaries and other structures, allows an easy grasping and extraction of the GSV vein through a 3 mm stab incision provided an ultrasonography assistance. The vein is divided/ligated about 2 cm distal from the ostium, the distal stump is cannulated and foam is injected on the distal segment from the E-point incision in a retrograde fashion, varices are avulsed by phlebectomy. Twenty procedures in 18 patients (venous clinical severity score: mean 3.15 - GSV diameter: mean 7.34 were performed, all the cases without inconveniences, with a duration not exceeding 10 min in addition to the phlebectomy procedure time. No complications as hemorrhage, infection, nerve lesion, lymphatic leak or thrombosis have been registered. At one month the residual saphenous stump length was in average 2.16 cm with complete closure of GSV in all. Three patients have been controlled at 6 months showing GSV complete closure. The procedure described is a simple office US assisted method for GSV ligationdivision, leaving the 2 last cm of the saphenofemoral junction. It could be associated to most of the procedures in use with limited additional time and resources required.

  16. Sensitive detection of Aβ protofibrils by proximity ligation - relevance for Alzheimer's disease

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    Gustafsdottir Sigrun

    2010-10-01

    Full Text Available Abstract Background Protein aggregation plays important roles in several neurodegenerative disorders. For instance, insoluble aggregates of phosphorylated tau and of Aβ peptides are cornerstones in the pathology of Alzheimer's disease. Soluble protein aggregates are therefore potential diagnostic and prognostic biomarkers for their cognate disorders. Detection of the aggregated species requires sensitive tools that efficiently discriminate them from monomers of the same proteins. Here we have established a proximity ligation assay (PLA for specific and sensitive detection of Aβ protofibrils via simultaneous recognition of three identical determinants present in the aggregates. PLA is a versatile technology in which the requirement for multiple target recognitions is combined with the ability to translate signals from detected target molecules to amplifiable DNA strands, providing very high specificity and sensitivity. Results For specific detection of Aβ protofibrils we have used a monoclonal antibody, mAb158, selective for Aβ protofibrils in a modified PLA, where the same monoclonal antibody was used for the three classes of affinity reagents required in the assay. These reagents were used for detection of soluble Aβ aggregates in solid-phase reactions, allowing detection of just 0.1 pg/ml Aβ protofibrils, and with a dynamic range greater than six orders of magnitude. Compared to a sandwich ELISA setup of the same antibody the PLA increases the sensitivity of the Aβ protofibril detection by up to 25-fold. The assay was used to measure soluble Aβ aggregates in brain homogenates from mice transgenic for a human allele predisposing to Aβ aggregation. Conclusions The proximity ligation assay is a versatile analytical technology for proteins, which can provide highly sensitive and specific detection of Aβ aggregates - and by implication other protein aggregates of relevance in Alzheimer's disease and other neurodegenerative disorders.

  17. Intrahepatic Left to Right Portoportal Venous Collateral Vascular Formation in Patients Undergoing Right Portal Vein Ligation

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    Lienden, K. P. van, E-mail: k.p.vanlienden@amc.uva.nl [Academic Medical Center, University of Amsterdam, Department of Interventional Radiology (Netherlands); Hoekstra, L. T. [Academic Medical Center, University of Amsterdam, Department of Surgery (Netherlands); Bennink, R. J. [Academic Medical Center, University of Amsterdam, Department of Nuclear Medicine (Netherlands); Gulik, T. M. van [Academic Medical Center, University of Amsterdam, Department of Surgery (Netherlands)

    2013-12-15

    Purpose: We investigated intrahepatic vascular changes in patients undergoing right portal vein ligation (PVL) or portal vein embolization (PVE) in conjunction with the ensuing hypertrophic response and function of the left liver lobe. Methods: Between December 2008 and October 2011, 7 patients underwent right PVL and 14 patients PVE. Computed tomographic (CT) volumetry to assess future remnant liver (FRL) and functional hepatobiliary scintigraphy were performed in all patients before and 3 weeks after portal vein occlusion. In 18 patients an intraoperative portography was performed to assess perfusion through the occluded portal branches. Results: In all patients after initially successful PVL, reperfused portal veins were observed on CT scan 3 weeks after portal occlusion. This was confirmed in all cases during intraoperative portography. Intrahepatic portoportal collaterals were identified in all patients in the PVL group and in one patient in the PVE group. In all other PVE patients, complete occlusion of the embolized portal branches was observed on CT scan and on intraoperative portography. The median increase of FRL volume after PVE was 41.6 % (range 10-305 %), and after PVL was only 8.1 % (range 0-102 %) (p = 0.179). There were no differences in FRL function between both groups. Conclusion: Preoperative PVE and PVL are both methods to induce hypertrophy of the FRL in anticipation of major liver resection. Compared to PVE, PVL seems less efficient in inducing hypertrophy of the nonoccluded left lobe. This could be caused by the formation of intrahepatic portoportal neocollateral vessels, through which the ligated portal branches are reperfused within 3 weeks.

  18. Ligation of intersphincteric fistula tract (LIFT) to treat anal fistula: systematic review and meta-analysis.

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    Hong, K D; Kang, S; Kalaskar, S; Wexner, S D

    2014-08-01

    Sphincter-preserving approaches to treat anal fistula do not jeopardize continence; however, healing rates are suboptimal. In this context, ligation of the intersphincteric fistula tract (LIFT) can be considered promising offering high success rates and a relatively simple procedure. This review aimed to investigate the outcomes of LIFT to treat anal fistula. We conducted a systematic review of the Pubmed, Web of Science, and Cochrane databases, to retrieve all relevant scientific original articles and scientific abstracts (Web of Science) related to the LIFT procedure for anal fistula between January 2007 and March 2013. The search yielded 24 original articles including 1,110 patients; these included one randomized controlled study, three case control studies, and 20 case series. Most studies included patients with trans-sphincteric or complex fistula, not amenable to fistulotomy. During a pooled mean 10.3 months of follow-up, the mean success, incontinence, intraoperative, and postoperative complication rates were 76.4, 0, 0, and 5.5%, respectively. A sensitivity analysis showed that the impact on success in terms of follow-up duration, study size, and combining other procedures was limited. There was no association between pre-LIFT drainage seton and success of LIFT. Ligation of the intersphincteric fistula tract appears to be an effective and safe treatment for trans-sphincteric or complex anal fistula. Combining other procedures and a pre-LIFT drainage seton does not seem to confer any added benefit in terms of success. However, given the lack of prospective randomized trials, interpretation of these data must be cautious. Further trials are mandatory to identify predictive factors for success, and true effectiveness of the LIFT compared to other sphincter-preserving procedures to treat anal fistula.

  19. Venous Ligation: A Novel Strategy for Glans Enhancement in Penile Prosthesis Implantation

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    Geng-Long Hsu

    2014-01-01

    Full Text Available Although penile implantation remains a final solution for patients with refractory impotence, undesirable postoperative effects, including penile size reduction and cold sensation of the glans penis, remain problematic. We report results of a surgical method designed to avoid these problems. From 2003 to 2013, 35 consecutive patients received a malleable penile implant. Of these, 15 men (the enhancing group were also treated with venous ligation of the retrocoronal venous plexus, deep dorsal vein, and cavernosal veins. The remaining 20 men formed the control group, treated with only a penile implant. Follow-up ranged from 1.1 to 10.0 years, with an average of 6.7 ± 1.5 years. Although preoperative glanular dimension did not differ significantly between the two groups, significant respective difference at one day and one year postoperatively was found in the glanular circumference (128.8 ± 6.8 mm versus 115.3 ± 7.2 mm and 130.6 ± 7.2 mm versus 100.5 ± 7.3 mm; both P<0.05, radius (38.8 ± 2.7 mm versus 37.1 ± 2.8 mm and 41.5 ± 2.6 mm versus 33.8 ± 2.9 mm; latter P<0.01, and satisfaction rate (91.7% versus 53.3%, P<0.01 as well. Based on our results, selective venous ligation appears to enhance the glans penis dimension in implant patients.

  20. PERIPANCREATIC ARTERIAL LIGATION COMBINED WITH ARTERIAL INFUSION REGIONAL CHEMOTHERAPY FOR TREATING PATIENTS WITH ADVANCED PANCREATIC CARCINOMA

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Objective To find out a new treatment method for advanced pancreatic carcinoma. Methods Twenty-nine patients with advanced pancreatic carcinoma and liver metastases were randomly divided into 2 groups.Group A (n=11) underwent bilio-enterostomy and/or gastro-enterostomy combined with systemic chemotherapy after operation;Group B(n=18) underwent bilio-enterostomy and/or gastro-enterostomy combined with peripancreatic arterial ligation and arterial infusion regional chemotherapy.The alleviation of clinical symptom,the change of carcinoma volume by BUS and CT scan,survival period and serum CEA were observed in two groups. Results The symptoms were alleviated apparently in most cases in Group B;BUS and CT scan showed that the tumor volume decreased apparently in Group B;The response rate was 67.7% in Group B,and 18.2% in Group A,respectively(P<0.01);the mean survival period was (4.8±0.6) months in Group A,and (12.5±1.2) months in Group B,respectively(P<0.01),there was significant difference between the two groups.The decrease of serum CEA was 54% in Group A and 60% in Group B,but the difference was not significant(P>0.05). Conclusion Peripancreatic arterial ligation combined with arterial infusion regional chmotherapy is believed to be effective against both pancreatic carcinoma and liver metastases,and it can alleviate the clinical symptoms,postpone the growth speed of tumor,and prolong the survival period.