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Sample records for added hydrogen donor

  1. Thermal cracking with hydrogen donor diluent

    SciTech Connect

    Derbyshire, F.; Varghese, P.; Whitehurst, D.D.

    1983-07-26

    An improved hydrogen donor for hydrogen donor diluent cracking is provided by extraction with naphtha from the cracked product and hydrogenation by hydrogen transfer from a lower boiling hydrogen donor such as tetralin.

  2. New biologically active hydrogen sulfide donors.

    PubMed

    Roger, Thomas; Raynaud, Francoise; Bouillaud, Frédéric; Ransy, Céline; Simonet, Serge; Crespo, Christine; Bourguignon, Marie-Pierre; Villeneuve, Nicole; Vilaine, Jean-Paul; Artaud, Isabelle; Galardon, Erwan

    2013-11-25

    Generous donors: The dithioperoxyanhydrides (CH3 COS)2 , (PhCOS)2 , CH3 COSSCO2 Me and PhCOSSCO2 Me act as thiol-activated hydrogen sulfide donors in aqueous buffer solution. The most efficient donor (CH3 COS)2 can induce a biological response in cells, and advantageously replace hydrogen sulfide in ex vivo vascular studies. PMID:24115650

  3. Hydrogen enhancement of silicon thermal donor formation

    NASA Astrophysics Data System (ADS)

    Lamp, C. D.; James, D. J., II

    1993-04-01

    Oxygen-related thermal donor formation in Czochralski silicon is characterized by the capacitance-voltage and deep level transient spectroscopy techniques as a function of 450 °C anneal time following hydrogenation. Increases in the formation rate and number of thermal donor (TD) defects found after hydrogenation are reported. This study finds an increase in TD+/++ concentration in the near-surface region at short anneal times, but at longer times an elevated concentration was not observed. No acceleration through the sequence of thermal donor defects was detected. This fails to support the model of hydrogen lowering the barrier to oxygen diffusion and accelerating the TDn→TDn+1 transitions. This study does, however, support a model in which the hydrogen increases the available thermal donor core sites.

  4. Alcohols as hydrogen-donor solvents for treatment of coal

    DOEpatents

    Ross, David S.; Blessing, James E.

    1981-01-01

    A method for the hydroconversion of coal by solvent treatment at elevated temperatures and pressure wherein an alcohol having an .alpha.-hydrogen atom, particularly a secondary alcohol such as isopropanol, is utilized as a hydrogen donor solvent. In a particular embodiment, a base capable of providing a catalytically effective amount of the corresponding alcoholate anion under the solvent treatment conditions is added to catalyze the alcohol-coal reaction.

  5. Hydrogen-donor coal liquefaction process

    DOEpatents

    Wilson, Jr., Edward L.; Mitchell, Willard N.

    1980-01-01

    Improved liquid yields are obtained during the hydrogen-donor solvent liquefaction of coal and similar carbonaceous solids by maintaining a higher concentration of material having hydrogenation catalytic activity in the downstream section of the liquefaction reactor system than in the upstream section of the system.

  6. Donor center formation in hydrogen implanted silicon

    NASA Astrophysics Data System (ADS)

    Neustroev, E. P.; Antonova, I. V.; Stas, V. F.; Popov, V. P.; Obodnikov, V. I.

    1999-10-01

    The shallow donor centers formed beyond the hydrogen projected range in temperature interval of 350-550°C have been studied in the present work. It has been shown that hydrogen implantation enhances thermal donor (TD) formation in the whole crystal (up to 360 μm). Two different mechanisms of enhancement must be distinguished. The first is a hydrogen-related increase in the TD formation rate, which provides a TD profile up to ∼150 μm described by a diffusion coefficient of 5×10 -9 cm 2/s at 450°C. The second mechanism of acceleration is connected to some mobile point defects (vacancy or interstitial type) from the implanted layer with a diffusion coefficient of about 1×10 -7 cm 2/s. The last mechanism is also manifested in the case of oxygen implantation.

  7. Nickel-catalyzed transfer hydrogenation of ketones using ethanol as a solvent and a hydrogen donor.

    PubMed

    Castellanos-Blanco, Nahury; Arévalo, Alma; García, Juventino J

    2016-09-14

    We report a nickel(0)-catalyzed direct transfer hydrogenation (TH) of a variety of alkyl-aryl, diaryl, and aliphatic ketones with ethanol. This protocol implies a reaction in which a primary alcohol serves as a hydrogen atom source and solvent in a one-pot reaction without any added base. The catalytic activity of the nickel complex [(dcype)Ni(COD)] (e) (dcype: 1,2-bis(dicyclohexyl-phosphine)ethane, COD: 1,5-cyclooctadiene), towards transfer hydrogenation (TH) of carbonyl compounds using ethanol as the hydrogen donor was assessed using a broad scope of ketones, giving excellent results (up to 99% yield) compared to other homogeneous phosphine-nickel catalysts. Control experiments and a mercury poisoning experiment support a homogeneous catalytic system; the yield of the secondary alcohols formed in the TH reaction was monitored by gas chromatography (GC) and NMR spectroscopy. PMID:27511528

  8. Hydrogen donor solvent coal liquefaction process

    DOEpatents

    Plumlee, Karl W.

    1978-01-01

    An indigenous hydrocarbon product stream boiling within a range of from about C.sub.1 -700.degree. F., preferably C.sub.1 -400.degree. F., is treated to produce an upgraded hydrocarbon fuel component and a component which can be recycled, with a suitable donor solvent, to a coal liquefaction zone to catalyze the reaction. In accordance therewith, a liquid hydrocarbon fraction with a high end boiling point range up to about 700.degree. F., preferably up to about 400.degree. F., is separated from a coal liquefaction zone effluent, the separated fraction is contacted with an alkaline medium to provide a hydrocarbon phase and an aqueous extract phase, the aqueous phase is neutralized, and contacted with a peroxygen compound to convert indigenous components of the aqueous phase of said hydrocarbon fraction into catalytic components, such that the aqueous stream is suitable for recycle to the coal liquefaction zone. Naturally occurring phenols and alkyl substituted phenols, found in the aqueous phase, are converted, by the addition of hydroxyl constituents to phenols, to dihydroxy benzenes which, as disclosed in copending Application Ser. Nos. 686,813 now U.S. Pat. No. 4,049,536; 686,814 now U.S. Pat. No. 4,049,537; 686,827 now U.S. Pat. No. 4,051,012 and 686,828, K. W. Plumlee et al, filed May 17, 1976, are suitable hydrogen transfer catalysts.

  9. Hydrogen added after-burner system

    SciTech Connect

    Kanada, Youji; Hayasi, Masaharu; Akaki, Motonobu; Tsuchikawa, Shunzou; Isomura, Akihito

    1996-09-01

    The authors developed a hydrogen-added afterburner system for a new catalyst heating system, which realized large reduction of emissions during start-up at low temperatures when hydrocarbon (HC) emission was rather high. Key development items of this system are a water electrolysis type small size on-board hydrogen supply unit and an engine matching technique for the verification of emission reduction effects.

  10. Are aromatic carbon donor hydrogen bonds linear in proteins?

    PubMed

    Nanda, Vikas; Schmiedekamp, Ann

    2008-02-01

    Proteins fold and maintain structure through the collective contributions of a large number of weak, noncovalent interactions. The hydrogen bond is one important category of forces that acts on very short distances. As our knowledge of protein structure continues to expand, we are beginning to appreciate the role that weak carbon-donor hydrogen bonds play in structure and function. One property that differentiates hydrogen bonds from other packing forces is propensity for forming a linear donor-hydrogen-acceptor orientation. To ascertain if carbon-donor hydrogen bonds are able to direct acceptor linearity, we surveyed the geometry of interactions specifically involving aromatic sidechain ring carbons in a data set of high resolution protein structures. We found that while donor-acceptor distances for most carbon donor hydrogen bonds were tighter than expected for van der Waals packing, only the carbons of histidine showed a significant bias for linear geometry. By categorizing histidines in the data set into charged and neutral sidechains, we found only the charged subset of histidines participated in linear interactions. B3LYP/6-31G**++ level optimizations of imidazole and indole-water interactions at various fixed angles demonstrates a clear orientation dependence of hydrogen bonding capacity for both charged and neutral sidechains. We suggest that while all aromatic carbons can participate in hydrogen bonding, only charged histidines are able to overcome protein packing forces and enforce linear interactions. The implications for protein modeling and design are discussed. PMID:17705268

  11. Hydrogen as an electron donor for dechlorination of tetrachloroethene by an anaerobic mixed culture.

    PubMed Central

    DiStefano, T D; Gossett, J M; Zinder, S H

    1992-01-01

    Hydrogen served as an electron donor in the reductive dechlorination of tetrachloroethene to vinyl chloride and ethene over periods of 14 to 40 days in anaerobic enrichment cultures; however, sustained dechlorination for more extended periods required the addition of filtered supernatant from a methanol-fed culture. This result suggests a nutritional dependency of hydrogen-utilizing dechlorinators on the metabolic products of other organisms in the more diverse, methanol-fed system. Vancomycin, an inhibitor of cell wall synthesis in eubacteria, was found to inhibit acetogenesis when added at 100 mg/liter to both methanol-fed and hydrogen-fed cultures. The effect of vancomycin on dechlorination was more complex. Methanol could not sustain dechlorination when vancomycin inhibited acetogenesis, while hydrogen could. These results are consistent with a model in which hydrogen is the electron donor directly used for dechlorination by organisms resistant to vancomycin and with the hypothesis that the role of acetogens in methanol-fed cultures is to metabolize a portion of the methanol to hydrogen. Methanol and other substrates shown to support dechlorination in pure and mixed cultures may merely serve as precursors for the formation of an intermediate hydrogen pool. This hypothesis suggests that, for bioremediation of high levels of tetrachloroethene, electron donors that cause the production of a large hydrogen pool should be selected or methods that directly use H2 should be devised. PMID:1482184

  12. Asymmetric Transfer Hydrogenation of Imines using Alcohol: Efficiency and Selectivity are Influenced by the Hydrogen Donor.

    PubMed

    Pan, Hui-Jie; Zhang, Yao; Shan, Chunhui; Yu, Zhaoyuan; Lan, Yu; Zhao, Yu

    2016-08-01

    The influence of the alcohol, as the hydrogen donor, on the efficiency and selectivity of the asymmetric transfer hydrogenation (ATH) of imines is reported for the first time. This discovery not only leads to a highly enantioselective access to N-aryl and N-alkyl amines, but also provides new insight into the mechanism of the ATH of imines. Both experimental and computational studies provide support for the reaction pathway involving an iridium alkoxide as the reducing species. PMID:27374880

  13. Hydrogen shallow donors in ZnO and rutile TiO2

    NASA Astrophysics Data System (ADS)

    Weber, Jörg; Lavrov, Edward V.; Herklotz, Frank

    2012-05-01

    A combined study of IR absorption, photoconductivity, photoluminescence and Raman measurements in ZnO samples supports the theoretical suggestions of a shallow bond-centered hydrogen donor and a shallow hydrogen donor within the oxygen vacancy. In rutile TiO2 we also identify a shallow hydrogen donor in contrast to recent theoretical predictions. A possible solution to this obvious discrepancy is proposed.

  14. Hydrogen Sulfide Donor GYY4137 Protects against Myocardial Fibrosis

    PubMed Central

    Meng, Guoliang; Zhu, Jinbiao; Xiao, Yujiao; Huang, Zhengrong; Zhang, Yuqing; Tang, Xin; Xie, Liping; Chen, Yu; Shao, Yongfeng; Ferro, Albert; Wang, Rui; Moore, Philip K.; Ji, Yong

    2015-01-01

    Hydrogen sulfide (H2S) is a gasotransmitter which regulates multiple cardiovascular functions. However, the precise roles of H2S in modulating myocardial fibrosis in vivo and cardiac fibroblast proliferation in vitro remain unclear. We investigated the effect of GYY4137, a slow-releasing H2S donor, on myocardial fibrosis. Spontaneously hypertensive rats (SHR) were administrated with GYY4137 by intraperitoneal injection daily for 4 weeks. GYY4137 decreased systolic blood pressure and inhibited myocardial fibrosis in SHR as evidenced by improved cardiac collagen volume fraction (CVF) in the left ventricle (LV), ratio of perivascular collagen area (PVCA) to lumen area (LA) in perivascular regions, reduced hydroxyproline concentration, collagen I and III mRNA expression, and cross-linked collagen. GYY4137 also inhibited angiotensin II- (Ang II-) induced neonatal rat cardiac fibroblast proliferation, reduced the number of fibroblasts in S phase, decreased collagen I and III mRNA expression and protein synthesis, attenuated oxidative stress, and suppressed α-smooth muscle actin (α-SMA), transforming growth factor-β1 (TGF-β1) expression as well as Smad2 phosphorylation. These results indicate that GYY4137 improves myocardial fibrosis perhaps by a mechanism involving inhibition of oxidative stress, blockade of the TGF-β1/Smad2 signaling pathway, and decrease in α-SMA expression in cardiac fibroblasts. PMID:26078813

  15. Hydrogen abstraction in the neutral molecular cluster of benzophenone and hydrogen donors formed in a supersonic free jet expansion

    SciTech Connect

    Matsushita, Yoshihisa; Kajii, Yoshizumi; Obi, Kinichi

    1992-08-06

    This paper discusses how benzophenone undergoes photoreduction to form benzophenone ketyl radical by an intracellular reaction in the benzophenone 1,4-cyclohexadiene mixed expansion in a supersonic free jet expansion. No ketyl radical fluorescence is observed when triethylamine, 2-propanol, or ethanol is the hydrogen donor; thus the normal molecular cluster activity depends on the nature of the hydrogen donor. 36 refs., 5 figs.

  16. Mathematical modeling of autotrophic denitrification (AD) process with sulphide as electron donor.

    PubMed

    Xu, Guihua; Yin, Fengjun; Chen, Shaohua; Xu, Yuanjian; Yu, Han-Qing

    2016-03-15

    Autotrophic denitrification (AD) plays a critical role in nitrate removal from organic carbon-deficient wastewaters with a high level of nitrogen oxides. However, the AD process is not included in the current denitrification models, which limits the application of AD technology for wastewater treatment. In this work, a kinetic model for AD process involved 4 processes and 5 components with 9 parameters is established to describe the sulphide biooxidation and nitrite removal process. In this model, 4 oxidation-reduction reactions using sulphide as electronic donor in the AD process are taken into account. The model parameters are optimized by fitting data from the experiments with different combinations of sulphide, sulphur, sulphate, nitrate and nitrite at various concentrations. Model calibration and validation results demonstrate that the developed model is able to reasonably describe the removal rates of nitrate, nitrite, sulphide and sulphur in the AD process. The model simulation results also show that the sulphur term (η(S)) in the kinetic equations of nitrate, nitrite, sulphur and sulphate remains constant, rather than being controlled by its own concentration. Furthermore, with this model the products of sulphide biooxidation in the AD process, sulphur and sulphate, and their concentrations can be accurately predicted. Therefore, this model provides a strategy to control the sulphate concentration below the discharge limits or recover sulphur as the main end product from sulphide biooxidation. PMID:26799712

  17. Hydrogen induced electric conduction in undoped ZnO and Ga-doped ZnO thin films: Creating native donors via reduction, hydrogen donors, and reactivating extrinsic donors

    SciTech Connect

    Akazawa, Housei

    2014-09-01

    The manner in which hydrogen atoms contribute to the electric conduction of undoped ZnO and Ga-doped ZnO (GZO) films was investigated. Hydrogen atoms were permeated into these films through annealing in an atmospheric H{sub 2} ambient. Because the creation of hydrogen donors competes with the thermal annihilation of native donors at elevated temperatures, improvements to electric conduction from the initial state can be observed when insulating ZnO films are used as samples. While the resistivity of conductive ZnO films increases when annealing them in a vacuum, the degree of increase is mitigated when they are annealed in H{sub 2}. Hydrogenation of ZnO crystals was evidenced by the appearance of OH absorption signals around a wavelength of 2700 nm in the optical transmittance spectra. The lowest resistivity that was achieved by H{sub 2} annealing was limited to 1–2 × 10{sup −2} Ω cm, which is one order of magnitude higher than that by native donors (2–3 × 10{sup −3} Ω cm). Hence, all native donors are converted to hydrogen donors. In contrast, GZO films that have resistivities yet to be improved become more conductive after annealing in H{sub 2} ambient, which is in the opposite direction of GZO films that become more resistive after vacuum annealing. Hydrogen atoms incorporated into GZO crystals should assist in reactivating Ga{sup 3+} donors.

  18. Roles of molecular hydrogen and a hydrogen donor solvent in the cracking of moal model compounds with dispersed catalysts

    SciTech Connect

    Suzuki, Toshimitsu; Ikenaga, Na-oki; Sakota, Takahiro

    1994-12-31

    It is of great importance to evaluate quantitative hydrogen transfer process by using coal model compounds with a hydrogen-donor solvent. Cronauer el al. showed that in the cracking of benzyl phenyl ether the hydrogen required to stabilize free radicals comes from a donor solvent or intramolecular rearrangement and not from gaseous hydrogen in the absence of a catalyst. Korobkov et al. and Schlosberg et al. showed that the thermolysis of benzyl phenyl ether and dibenzyl ether were accomplished by intramolecular rearrangements. Yokokawa et al. reported that tetralin retarded the catalyzed hydrocracking of coal model compounds containing C-C and C-O bonds. However, few studies dealt with quantitative discussion in the hydrogen transfer process from a hydrogen-donor solvent or molecular hydrogen to free radicals derived from a model compound except a series of studies by Nicole and co-workers. On the other hand, it is well known that the amount of naphthalene produced from tetralin decreases after the liquefaction of coal in tetralin with catalyst as compared to the liquefaction in the absence of catalysts. To account for this, two mechanisms are proposed. One is that the catalyst hydrogenates naphthalene produced from tetralin, and the other is that the catalyst promotes the direct hydrogen transfer from molecular hydrogen to free radicals. The purpose of this work is to elucidate the role of catalyst and tetralin by means of the quantitative treatment of the hydrogen transfer reaction stabilizing thermally decomposed free radicals. Cracking of benzyl phenyl ether (BPE), dibenzyl ether (DBE), 1,2-diphenylethane, and 1,3-diphenylpropane was studied in tetralin in the presence of highly disposed catalyst.

  19. Fano resonances in photoconductivity spectra of hydrogen donors in ZnO and rutile

    NASA Astrophysics Data System (ADS)

    Lavrov, E. V.; Herklotz, F.; Weber, J.

    2015-02-01

    The results of photoconductivity studies of hydrogen donors in ZnO and rutile TiO2 are presented. It is shown that local vibrational modes of O-H bonds comprising donors in both semiconductors can be detected in photoconductivity spectra as Fano resonances at 3611 and 3290 cm-1 in the case of ZnO and TiO2, respectively. The frequencies of these features red-shift in energy down to 2668 (ZnO) and 2445 cm-1 (TiO2) if hydrogen is substituted by deuterium. Based on the frequency of the deuterium resonance it is concluded that the ionization energy of the hydrogen donor in TiO2 is less than 300 meV, which is in variance with predictions of theory. The reasons for such a discrepancy are discussed.

  20. Extraction of reference eastern shale with hydrogen donor and nondonor solvents

    SciTech Connect

    McKay, J.F.; Blanche, M.S.

    1985-09-01

    Oil shale from the New Albany Formation in Bullitt County, Kentucky, was treated with water together with hydrogen-donor and nondonor solvents at 400/sup 0/C and extracted with benzene-methanol. The purpose of the experiments was to measure the amount of liquid organic material recovered with hydrogen-donor and nondonor solvents. Liquid organic material amounting to approximately double that recovered by a Fischer assay experiment was recovered with tetralin, a hydrogen-donor solvent, and with naphthalene, a nondonor solvent. The shale was also treated with tetralin and water for periods of 5 minutes to 60 minutes to measure the effect of time on yield of liquid product. The results showed that yields increased with time and that treatment times of about 30 minutes were required to recover more liquid product than that produced by a Fischer assay experiment. 10 refs., 1 fig., 2 tabs.

  1. Fundamental Kinetics of Supercritical Coal Liquefaction: Effect of Catalysts and Hydrogen-Donor Solvents

    SciTech Connect

    McCoy, Ben J; Madras, Girodhar; Smith, J M; Kodera, Yoichi

    1997-04-16

    This is the quarterly report on our recent progress toward the overall objective to understand the supercritical fluid extraction of hydrocarbons from coal. Our strategy is to simulate coal as a high molecular-weight polymeric material by studying the degradation of polymers under various conditions. The hypothesis we are testing is that degradation of such macromolecules is applicable to the decomposition (depolymerization) of the coal network. Polymer degradation and coal liquefaction are influenced strongly by the solvent in the reaction. This motivated our investigation of the effect of hydrogen donor solvents on polymer degradation. In particular, we obtained new experimental data to show how a hydrogen donor, 6-hydroxy tetralin, influences the degradation rate of polystyrene. We also developed a detailed radical mechanism for hydrogen donation based on the Rice-Herzfeld chain reaction concept with the elementary steps of initiation, depropagation, hydrogen abstraction, and termination. Expressions for the degradation rate parameters were obtained by applying continuous distribution kinetics to the MWD of the reacting polymer. The theory explains the different influences of the hydrogen donor solvent on the degradation rate coefficients for different polymers. Though developed for the degradation of polymers, the mechanism and the theory are potentially applicable for chain scission and addition reactions among distributions of paraffins, olefins, and radicals of all chain lengths. The concepts can, in principle, be extended to examine the effect of hydrogen donors on coal liquefaction and on the complex mixture of liquefaction compounds. Based on this work, a research paper titled "Effect of Hydrogen Donors on Polymer Degradation", has been submitted for publication. Our research paper entitled, "Molecular weight effect on the dynamics of polystyrene degradation", has been accepted for publication by the journal, Industrial and Engineering Chemistry Research.

  2. Enhancement in Organic Photovoltaic Efficiency through the Synergistic Interplay of Molecular Donor Hydrogen Bonding and -Stacking

    DOE PAGESBeta

    Shewmon, Nathan; Watkins, Davita; Galindo, Johan; Zerdan, Raghida; Chen, Jihua; Keum, Jong Kahk; Roitberg, Adrian; Xue, Jiangeng; Castellano, Ronald

    2015-07-20

    For organic photovoltaic (OPV) cells based on the bulk heterojunction (BHJ) structure, it remains challenging to rationally control the degree of phase separation and percolation within blends of donors and acceptors to secure optimal charge separation and transport. Reported is a bottom-up, supramolecular approach to BHJ OPVs wherein tailored hydrogen bonding (H-bonding) interactions between π-conjugated electron donor molecules encourage formation of vertically aligned donor π-stacks while simultaneously suppressing lateral aggregation; the programmed arrangement facilitates fine mixing with fullerene acceptors and efficient charge transport. The approach is illustrated using conventional linear or branched quaterthiophene donor chromophores outfitted with terminal functional groupsmore » that are either capable or incapable of self-complementary H-bonding. When applied to OPVs, the H-bond capable donors yield a twofold enhancement in power conversion efficiency relative to the comparator systems, with a maximum external quantum efficiency of 64%. H-bond promoted assembly results in redshifted absorption (in neat films and donor:C 60 blends) and enhanced charge collection efficiency despite disparate donor chromophore structure. Both features positively impact photocurrent and fill factor in OPV devices. Film structural characterization by atomic force microscopy, transmission electron microscopy, and grazing incidence wide angle X-ray scattering reveals a synergistic interplay of lateral H-bonding interactions and vertical π-stacking for directing the favorable morphology of the BHJ.« less

  3. Enhancement in Organic Photovoltaic Efficiency through the Synergistic Interplay of Molecular Donor Hydrogen Bonding and -Stacking

    SciTech Connect

    Shewmon, Nathan; Watkins, Davita; Galindo, Johan; Zerdan, Raghida; Chen, Jihua; Keum, Jong Kahk; Roitberg, Adrian; Xue, Jiangeng; Castellano, Ronald

    2015-07-20

    For organic photovoltaic (OPV) cells based on the bulk heterojunction (BHJ) structure, it remains challenging to rationally control the degree of phase separation and percolation within blends of donors and acceptors to secure optimal charge separation and transport. Reported is a bottom-up, supramolecular approach to BHJ OPVs wherein tailored hydrogen bonding (H-bonding) interactions between π-conjugated electron donor molecules encourage formation of vertically aligned donor π-stacks while simultaneously suppressing lateral aggregation; the programmed arrangement facilitates fine mixing with fullerene acceptors and efficient charge transport. The approach is illustrated using conventional linear or branched quaterthiophene donor chromophores outfitted with terminal functional groups that are either capable or incapable of self-complementary H-bonding. When applied to OPVs, the H-bond capable donors yield a twofold enhancement in power conversion efficiency relative to the comparator systems, with a maximum external quantum efficiency of 64%. H-bond promoted assembly results in redshifted absorption (in neat films and donor:C 60 blends) and enhanced charge collection efficiency despite disparate donor chromophore structure. Both features positively impact photocurrent and fill factor in OPV devices. Film structural characterization by atomic force microscopy, transmission electron microscopy, and grazing incidence wide angle X-ray scattering reveals a synergistic interplay of lateral H-bonding interactions and vertical π-stacking for directing the favorable morphology of the BHJ.

  4. Therapeutic application of hydrogen sulfide donors: the potential and challenges.

    PubMed

    Wu, Dan; Hu, Qingxun; Zhu, Yizhun

    2016-03-01

    Hydrogen sulfide (H2S), a colorless gas smelling of rotten egg, has long been considered a toxic gas and environment hazard. However, evidences show that H2S plays a great role in many physiological and pathological activities, and it exhibits different effects when applied at various doses. In this review, we summarize the chemistry and biomedical applications of H2S-releasing compounds, including inorganic salts, phosphorodithioate derivatives, derivatives of Allium sativum extracts, derivatives of thioaminoacids, and derivatives of antiinflammatory drugs. PMID:26597301

  5. Improved actuated strain of dielectric elastomer through disruption of hydrogen bonds of thermoplastic polyurethane by adding diaminonaphthalene

    NASA Astrophysics Data System (ADS)

    Ning, Nanying; Yan, Bingyue; Liu, Suting; Yao, Yang; Zhang, Liqun; Chan, Tung W.; Nishi, Toshio; Tian, Ming

    2015-03-01

    We used a novel and simple approach to increase the actuated strain at low electric field of thermoplastic polyurethane (TPU) through the disruption of the hydrogen bonds of TPU by adding diaminonaphthalene (DAN) into the matrix. DAN as proton donors disrupted the original N-H/C=O hydrogen bonds between the TPU chains, improving the polarizability of the chains, thus increasing the dielectric constant of TPU. Meanwhile, DAN greatly decreased the elastic modulus of TPU by disrupting the hydrogen bonds of TPU. The simultaneous increase in dielectric constant and decrease in elastic modulus resulted in a 330% increase in electromechanical sensitivity at 103 Hz and a 500% increase in actuated strain at the low electric field of 20 V μm-1, facilitating the application of dielectric elastomers (DEs) in the biological and medical fields, where a low electric field is required. In addition, our DAN/TPU DE exhibited good mechanical strength.

  6. Preorganized Hydrogen Bond Donor Catalysts: Acidities and Reactivities.

    PubMed

    Samet, Masoud; Kass, Steven R

    2015-08-01

    Measured DMSO pKa values for a series of rigid tricyclic adamantane-like triols containing 0-3 trifluoromethyl groups (i.e., 3(0)-3(3)) are reported. The three compounds with CF3 substituents are similar or more acidic than acetic acid (pKa = 13.5 (3(1)), 9.5 (3(2)), 7.3 (3(3)) vs 12.6 (HOAc)), and the resulting hydrogen bond network enables a remote γ-trifluoromethyl group to enhance the acidity as well as one located at the α-position. Catalytic abilities of 3(0)-3(3) were also examined. In a nonpolar environment a rate enhancement of up to 100-fold over flexible acyclic analogs was observed presumably due to an entropic advantage of the locked-in structure. Gas-phase acidities are found to correlate with the catalytic activity better than DMSO pKa values and appear to be a better measure of acidities in low dielectric constant media. These trends are reduced or reversed in polar solvents highlighting the importance of the reaction environment. PMID:26140305

  7. Correlation of Hydrogen-Atom Abstraction Reaction Efficiencies for Aryl Radicals with their Vertical Electron Affinities and the Vertical Ionization Energies of the Hydrogen Atom Donors

    PubMed Central

    Jing, Linhong; Nash, John J.

    2009-01-01

    The factors that control the reactivities of aryl radicals toward hydrogen-atom donors were studied by using a dual-cell Fourier-transform ion cyclotron resonance mass spectrometer (FT – ICR). Hydrogen-atom abstraction reaction efficiencies for two substrates, cyclohexane and isopropanol, were measured for twenty-three structurally different, positively-charged aryl radicals, which included dehydrobenzenes, dehydronaphthalenes, dehydropyridines, and dehydro(iso)quinolines. A logarithmic correlation was found between the hydrogen-atom abstraction reaction efficiencies and the (calculated) vertical electron affinities (EA) of the aryl radicals. Transition state energies calculated for three of the aryl radicals with isopropanol were found to correlate linearly with their (calculated) EAs. No correlation was found between the hydrogen-atom abstraction reaction efficiencies and the (calculated) enthalpy changes for the reactions. Measurement of the reaction efficiencies for the reactions of several different hydrogen-atom donors with a few selected aryl radicals revealed a logarithmic correlation between the hydrogen-atom abstraction reaction efficiencies and the vertical ionization energies (IE) of the hydrogen-atom donors, but not the lowest homolytic X – H (X = heavy atom) bond dissociation energies of the hydrogen-atom donors. Examination of the hydrogen-atom abstraction reactions of twenty-nine different aryl radicals and eighteen different hydrogen-atom donors showed that the reaction efficiency increases (logarithmically) as the difference between the IE of the hydrogen-atom donor and the EA of the aryl radical decreases. This dependence is likely to result from the increasing polarization, and concomitant stabilization, of the transition state as the energy difference between the neutral and ionic reactants decreases. Thus, the hydrogen-atom abstraction reaction efficiency for an aryl radical can be “tuned” by structural changes that influence either

  8. Donor level of interstitial hydrogen in semiconductors: Deep level transient spectroscopy

    NASA Astrophysics Data System (ADS)

    Kolkovsky, Vl.; Dobaczewski, L.; Nielsen, K. Bonde; Kolkovsky, V.; Larsen, A. Nylandsted; Weber, J.

    2009-12-01

    The behaviour of hydrogen in crystalline semiconductors has attracted considerable interest during several decades. Due to its high diffusion rate and ability to react with a wide variety of lattice imperfections such as intrinsic point defects, impurities, interfaces and surfaces, hydrogen is an impurity of fundamental importance in semiconductor materials. It has been already evidenced in previous investigations that the most fundamental hydrogen-related defects in-group IV semiconductors are interstitial hydrogen atoms occupying the bond-centre site ( BC) or the interstitial tetrahedral site ( T). Using first-principles calculations Van de Walle predicted similar properties of isolated hydrogen in other II-VI and III-V semiconductors. Another interesting prediction shown in that work was the existence of a universal alignment for the hydrogen electronic (-/+) level. Until now there is no direct experimental information regarding the individual isolated hydrogen states in compound semiconductors and most reported properties have been inferred indirectly. In the present work in-situ conventional deep level transient spectroscopy (DLTS) and high-resolution Laplace DLTS techniques are used to analyse hydrogen-related levels after low-temperature proton implantation in different II-VI and III-V semiconductors including GaAs, ZnO and CdTe. From these experimental observations the donor level of isolated hydrogen is found to keep almost a constant value in the absolute energy scale taking into account different band-offsets calculated for the whole group of semiconductors.

  9. Hydrogenic donor impurity in parallel-triangular quantum wires: Hydrostatic pressure and applied electric field effects

    NASA Astrophysics Data System (ADS)

    Restrepo, R. L.; Giraldo, E.; Miranda, G. L.; Ospina, W.; Duque, C. A.

    2009-12-01

    The combined effects of the hydrostatic pressure and in-growth direction applied electric field on the binding energy of hydrogenic shallow-donor impurity states in parallel-coupled-GaAs- Ga1-xAlxAs-quantum-well wires are calculated using a variational procedure within the effective-mass and parabolic-band approximations. Results are obtained for several dimensions of the structure, shallow-donor impurity positions, hydrostatic pressure, and applied electric field. Our results suggest that external inputs such us hydrostatic pressure and in-growth direction electric field are two useful tools in order to modify the binding energy of a donor impurity in parallel-coupled-quantum-well wires.

  10. Hydrogen: Adding Value and Flexibility to the Nuclear Power Industry

    SciTech Connect

    Lee, J.; Bhatt, V.; Friley, P.; Horak, W.; Reisman, A.

    2004-10-04

    The objective of this study was to assess potential synergies between the hydrogen economy and nuclear energy options. Specifically: to provide a market analysis of advanced nuclear energy options for hydrogen production in growing hydrogen demand; to conduct an impact evaluation of nuclear-based hydrogen production on the economics of the energy system, environmental emissions, and energy supply security; and to identify competing technologies & challenges to nuclear options.

  11. Hydrogen atom donor compounds as contrast enhancers for black-and-white photothermographic and thermographic elements

    DOEpatents

    Harring, Lori S.; Simpson, Sharon M.; Sansbury, Francis H.

    1997-01-01

    Hydrogen atom donor compounds are useful as contrast enhancers when used in combination with (i) hindered phenol developers, and (ii) trityl hydrazide and/or formyl-phenyl hydrazine co-developers, to produce ultra-high contrast black-and-white photothermographic and thermographic elements. The photothermographic and thermographic elements may be used as a photomask in a process where there is a subsequent exposure of an ultraviolet or short wavelength visible radiation-sensitive imageable medium.

  12. Rashba spin splitting in quantum nanowires in the presence of hydrogenic donor impurity

    NASA Astrophysics Data System (ADS)

    Safaei, Y.; Davatolhagh, S.; Golshan, M. M.

    2013-12-01

    The electronic subband states in the presence of hydrogenic donor impurity in quantum nanowires at the interface of semiconductor heterostructures devoid of structural inversion symmetry, are modeled and described in terms of a quasi-one-dimensional hydrogen atom with Rashba spin-orbit coupling. The energy levels and the spin-dependent subband states of the corresponding one-electron Schrodinger equation, are obtained using a two-step analytic solution as a function of the width L of the nanowire and the strength of the Rashba spin-orbit coupling α. The results thus obtained are checked against purely perturbative calculations in the limit of small spin-orbit coupling. In particular, it is found that the level splitting in a suitable range of the control parameters, L and α, results in spin-dependent electronic states of negative energy (bound states) as well as positive energy (scattering states). This novel result is of considerable interest for the generation of spin currents in the presence of hydrogenic donor impurity, as electrons in the scattering states can contribute to a spin current while those in the bound states tend to remain bound to the hydrogenic impurity.

  13. Electric-field control of a hydrogenic donor's spin in a semiconductor

    NASA Astrophysics Data System (ADS)

    de, Amrit; Pryor, Craig E.; Flatté, Michael E.

    2009-03-01

    The orbital wave function of an electron bound to a single donor in a semiconductor can be modulated by an applied AC electric field, which affects the electron spin dynamics via the spin-orbit interaction. Numerical calculations of the spin dynamics of a single hydrogenic donor (Si) using a real-space multi-band k.p formalism show that in addition to breaking the high symmetry of the hydrogenic donor state, the g-tensor has a strong nonlinear dependence on the applied fields. By explicitly integrating the time dependent Schr"odinger equation it is seen that Rabi oscillations can be obtained for electric fields modulated at sub-harmonics of the Larmor frequency. The Rabi frequencies obtained from sub-harmonic modulation depend on the magnitudes of the AC and DC components of the electric field. For a purely AC field, the highest Rabi frequency is obtained when E is driven at the 2nd sub-harmonic of the Larmor frequency. Apart from suggesting ways to measure g-tensor anisotropies and nonlinearities, these results also suggest the possibility of direct frequency domain measurements of Rabi frequencies.

  14. Autotrophic antimonate bio-reduction using hydrogen as the electron donor.

    PubMed

    Lai, Chun-Yu; Wen, Li-Lian; Zhang, Yin; Luo, Shan-Shan; Wang, Qing-Ying; Luo, Yi-Hao; Chen, Ran; Yang, Xiaoe; Rittmann, Bruce E; Zhao, He-Ping

    2016-01-01

    Antimony (Sb), a toxic metalloid, is soluble as antimonate (Sb(V)). While bio-reduction of Sb(V) is an effective Sb-removal approach, its bio-reduction has been coupled to oxidation of only organic electron donors. In this study, we demonstrate, for the first time, the feasibility of autotrophic microbial Sb(V) reduction using hydrogen gas (H2) as the electron donor without extra organic carbon source. SEM and EDS analysis confirmed the production of the mineral precipitate Sb2O3. When H2 was utilized as the electron donor, the consortium was able to fully reduce 650 μM of Sb(V) to Sb(III) in 10 days, a rate comparable to the culture using lactate as the electron donor. The H2-fed culture directed a much larger fraction of it donor electrons to Sb(V) reduction than did the lactate-fed culture. While 98% of the electrons from H2 were used to reduce Sb(V) by the H2-fed culture, only 12% of the electrons from lactate was used to reduce Sb(V) by the lactate-fed culture. The rest of the electrons from lactate went to acetate and propionate through fermentation, to methane through methanogenesis, and to biomass synthesis. High-throughput sequencing confirmed that the microbial community for the lactate-fed culture was much more diverse than that for the H2-fed culture, which was dominated by a short rod-shaped phylotype of Rhizobium (α-Protobacteria) that may have been active in Sb(V) reduction. PMID:26519630

  15. Hydrogen Fuel Capability Added to Combustor Flametube Rig

    NASA Technical Reports Server (NTRS)

    Frankenfield, Bruce J.

    2003-01-01

    Facility capabilities have been expanded at Test Cell 23, Research Combustor Lab (RCL23) at the NASA Glenn Research Center, with a new gaseous hydrogen fuel system. The purpose of this facility is to test a variety of fuel nozzle and flameholder hardware configurations for use in aircraft combustors. Previously, this facility only had jet fuel available to perform these various combustor flametube tests. The new hydrogen fuel system will support the testing and development of aircraft combustors with zero carbon dioxide (CO2) emissions. Research information generated from this test rig includes combustor emissions and performance data via gas sampling probes and emissions measuring equipment. The new gaseous hydrogen system is being supplied from a 70 000-standard-ft3 tube trailer at flow rates up to 0.05 lb/s (maximum). The hydrogen supply pressure is regulated, and the flow is controlled with a -in. remotely operated globe valve. Both a calibrated subsonic venturi and a coriolis mass flowmeter are used to measure flow. Safety concerns required the placement of all hydrogen connections within purge boxes, each of which contains a small nitrogen flow that is vented past a hydrogen detector. If any hydrogen leaks occur, the hydrogen detectors alert the operators and automatically safe the facility. Facility upgrades and modifications were also performed on other fluids systems, including the nitrogen gas, cooling water, and air systems. RCL23 can provide nonvitiated heated air to the research combustor, up to 350 psig at 1200 F and 3.0 lb/s. Significant modernization of the facility control systems and the data acquisition systems was completed. A flexible control architecture was installed that allows quick changes of research configurations. The labor-intensive hardware interface has been removed and changed to a software-based system. In addition, the operation of this facility has been greatly enhanced with new software programming and graphic operator interface

  16. Transition Metal Carbonyls Combined with Hydrogen Donors as Initiators of the Radical Reduction of Trichloromethyl Compounds

    NASA Astrophysics Data System (ADS)

    Freidlina, R. Kh; Gasanov, Rashid G.; Kuz'mina, Nadezhda A.; Chukovskaya, E. Ts

    1985-07-01

    The review is devoted to new redox catalysts of the homolytic reduction of trichloromethyl compounds to dichloromethyl compounds — mononuclear and dinuclear metal carbonyls [Fe(CO)5, Ni(CO)4, M(CO)6 (M = Mo, Cr, W), Mn2(CO)10] in combination with hydrogen donors (secondary alcohols, silicon hydrides, mercaptans, tertiary amines, amides, and tetrahydrofuran). The results obtained hitherto concerning the development of a new radical-chain method for the reduction of a wide variety of trichloromethyl compounds to the dichloromethyl derivatives are surveyed. The bibliography includes 78 references.

  17. Electronic Structure of Hydrogen Donors in Semiconductors and Insulators Probed by Muon Spin Rotation

    NASA Astrophysics Data System (ADS)

    Shimomura, Koichiro; Ito, Takashi U.

    2016-09-01

    Hydrogen in semiconductors and insulators plays a crucial role in their electric conductivity. Substantial experimental and theoretical efforts have been made to establish this hypothesis in the last decade, and the muon spin rotation technique has played a pioneering role. Positive muons implanted into such low-carrier systems often form a muonium (an analogue of hydrogen, the bound state of a positive muon and an electron). Although its dynamical aspect may be different from the heavier hydrogen, the electronic structure of the muonium is expected to be identical to that of hydrogen after a small correction of the reduced mass (˜0.4%). Since the discovery of a shallow muonium in CdS, its properties have been intensively studied in many semiconductors and insulators, and then it was interpreted as a possible origin of n-type conductivity under the context of a classical shallow donor model. In this article, we will describe the principle of muonium experiments and survey recent achievements in this field.

  18. Magnetic resonance spectroscopy of hydrogen shallow donors in aluminum-doped zinc oxide prepared by sol-gel processing

    NASA Astrophysics Data System (ADS)

    Park, J. K.; Lee, K. W.; Lee, W.; Lee, Cheol Eui; Kim, D.-J.; Park, W.

    2012-01-01

    Hydrogen shallow donors in sol-gel-prepared pristine and Al-doped ZnO systems have been investigated by electron paramagnetic resonance (EPR) and nuclear magnetic resonance (NMR) measurements. It is shown that the hydrogen shallow donors in the Al-doped ZnO system mostly occupy the interstitial sites as in the case of the pristine ZnO system. Our high-resolution NMR measurements sensitively reflected the slightly distinct lattice environments in the pristine and Al-doped ZnO systems.

  19. Garlic-derived natural polysulfanes as hydrogen sulfide donors: Friend or foe?

    PubMed

    Yagdi, Esma; Cerella, Claudia; Dicato, Mario; Diederich, Marc

    2016-09-01

    In vitro and in vivo studies reported the anti-cancer potential of organosulfur compounds (OSCs) as they trigger biological effects leading to cell cycle arrest with accumulation of cells in G2/M, alteration of the microtubular network, modulation of Bcl-2 family protein expression patterns and changes of the redox status. Despite these well-described effects, no OSC derivative is yet undergoing clinical trials even though their chemistry is well understood as OSCs act as hydrogen sulfide (H2S) donors. H2S is a biological mediator, synthesized through cysteine degradation and modulates vasodilation, cytoprotection, inflammation and angiogenesis. It is well accepted that H2S plays a biphasic pharmacological role: the inhibition of endogenous synthesis of H2S and paradoxically also the use of H2S donors to increase H2S concentration, induce both anti-cancer effects leading therefore to controversial discussions. Altogether, the role of H2S in the anti-cancer action of OSCs remains poorly understood. In this review, we hypothesize that OSCs act through H2S signaling pathways in cancer cells, and that a clearer understanding of the mechanism of action of H2S in OSC-mediated anti-cancer activity is required for further application of these compounds in translational medicine. PMID:27430419

  20. Enhanced photoproduction of hydrogen peroxide by humic substances in the presence of phenol electron donors.

    PubMed

    Zhang, Yi; Simon, Kelli A; Andrew, Andrea A; Del Vecchio, Rossana; Blough, Neil V

    2014-11-01

    Addition of a series of phenol electron donors to solutions of humic substances (HS) enhanced substantially the initial rates of hydrogen peroxide (H2O2) photoproduction (RH2O2), with enhancement factors (EF) ranging from a low of ∼3 for 2,4,6-trimethylphenol (TMP) to a high of ∼15 for 3,4-dimethoxyphenol (DMOP). The substantial inhibition of the enhanced RH2O2 following borohydride reduction of the HS, as well as the dependence of RH2O2 on phenol and dioxygen concentrations are consistent with a mechanism in which the phenols react with the triplet excited states of (aromatic) ketones within the HS to form initially a phenoxy and ketyl radical. The ketyl radical then reacts rapidly with dioxygen to regenerate the ketone and form superoxide (O2-), which subsequently dismutates to H2O2. However, as was previously noted for the photosensitized loss of TMP, the incomplete inhibition of the enhanced RH2O2 following borohydride reduction suggests that there may remain another pool of oxidizing triplets. The results demonstrate that H2O2 can be generated through an additional pathway in the presence of sufficiently high concentrations of appropriate electron donors through reaction with the excited triplet states of aromatic ketones and possibly of other species such as quinones. However, in some cases, the much lower ratio of H2O2 produced to phenol consumed suggests that secondary reactions could alter this ratio significantly. PMID:25288017

  1. Tunnel barrier design in donor nanostructures defined by hydrogen-resist lithography

    NASA Astrophysics Data System (ADS)

    Pascher, Nikola; Hennel, Szymon; Mueller, Susanne; Fuhrer, Andreas

    2016-08-01

    A four-terminal donor quantum dot (QD) is used to characterize potential barriers between degenerately doped nanoscale contacts. The QD is fabricated by hydrogen-resist lithography on Si(001) in combination with n-type doping by phosphine. The four contacts have different separations (d = 9, 12, 16 and 29 nm) to the central 6 nm × 6 nm QD island, leading to different tunnel and capacitive coupling. Cryogenic transport measurements in the Coulomb-blockade (CB) regime are used to characterize these tunnel barriers. We find that field enhancement near the apex of narrow dopant leads is an important effect that influences both barrier breakdown and the magnitude of the tunnel current in the CB transport regime. From CB-spectroscopy measurements, we extract the mutual capacitances between the QD and the four contacts, which scale inversely with the contact separation d. The capacitances are in excellent agreement with numerical values calculated from the pattern geometry in the hydrogen resist. Furthermore, we show that by engineering the source–drain tunnel barriers to be asymmetric, we obtain a much simpler excited-state spectrum of the QD, which can be directly linked to the orbital single-particle spectrum.

  2. Dinuclear zinc(II) complexes with hydrogen bond donors as structural and functional phosphatase models.

    PubMed

    Bosch, Simone; Comba, Peter; Gahan, Lawrence R; Schenk, Gerhard

    2014-09-01

    It is becoming increasingly apparent that the secondary coordination sphere can have a crucial role in determining the functional properties of biomimetic metal complexes. We have therefore designed and prepared a variety of ligands as metallo-hydrolase mimics, where hydrogen bonding in the second coordination sphere is able to influence the structure of the primary coordination sphere and the substrate binding. The assessment of a structure-function relationship is based on derivates of 2,6-bis{[bis(pyridin-2-ylmethyl)amino]methyl}-4-methylphenol (HBPMP = HL(1)) and 2-{[bis(pyridin-2-ylmethyl)amino]methyl}-6-{[(2-hydroxybenzyl)(pyridin-2-ylmethyl)amino]methyl}-4-methylphenol (H2BPBPMP = H2L(5)), well-known phenolate-based ligands for metallo-hydrolase mimics. The model systems provide similar primary coordination spheres but site-specific modifications in the secondary coordination sphere. Pivaloylamide and amine moieties were chosen to mimic the secondary coordination sphere of the phosphatase models, and the four new ligands H3L(2), H3L(3), HL(4), and H4L(6) vary in the type and geometric position of the H-bond donors and acceptors, responsible for the positioning of the substrate and release of the product molecules. Five dinuclear Zn(II) complexes were prepared and structurally characterized in the solid, and four also in solution. The investigation of the phosphatase activity of four model complexes illustrates the impact of the H-bonding network: the Michaelis-Menten constants (catalyst-substrate binding) for all complexes that support hydrogen bonding are smaller than for the reference complex, and this generally leads to higher catalytic efficiency and higher turnover numbers. PMID:25119813

  3. Hydrogen impurities and shallow donors in SnO2 studied by infrared spectroscopy

    SciTech Connect

    BEKISLI, F; Stavola, M.; FOWLER, W B; Boatner, Lynn A; Spahr, E. J.; Lüpke, G.

    2011-01-01

    Hydrogen has been found to be an important source of n-type conductivity in the transparent conducting oxide SnO2. We have studied the properties of H in SnO2 single crystals with infrared spectroscopy. When H or D is introduced into SnO2 by annealing in an H2 or D2 ambient at elevated temperature, several O-H and O-D vibrational lines are produced along with the low-frequency absorption that is characteristic of free carriers. To probe the relationship between H and the free carriers it introduces, the thermal stability of the free carrier absorption, and its relationship to the thermal stabilities of the O-H lines have been examined. Two H-related donors are found, one that is stable at room temperature on a time scale of weeks and a second that is stable up to 600 C. These electrically active defects are found to interact with other O-H centers and can be converted from one to another by thermal treatments. The vibrational modes have been found to have distinctive polarization properties that provide an important test of microscopic defect models for the several O-H and (O-H)2 centers that we have observed.

  4. Characterisation of potential barriers in a donor quantum dot defined by hydrogen resist lithography

    NASA Astrophysics Data System (ADS)

    Fuhrer, Andreas; Pascher, Nikola

    We use a four terminal donor quantum dot (QD) to characterize potential barriers between degenerately doped nanoscale contacts. The QD is fabricated by hydrogen resist lithography on Si(001) in combination with n-type doping from the gas-phase. The four contacts have different separations (d = 9, 12, 16 and 29 nm) to a central 6 nm x 6 nm island, leading to different tunnel- and capacitive coupling. We use cryogenic transport measurements in the Coulomb blockade regime to simultaneously probe current flow in the four terminals for various voltage configurations. The magnitude of the measured tunnelling currents as a function of applied bias and contact separation sets a limit of about 15 nm for tunnelling contacts and shows a strong increase of the barrier transmission with applied bias. Using a constant interaction picture we extract the mutual capacitances between the QD and the four contacts which are found to be in excellent agreement with numerically calculated values. Our results contribute to a better understanding of tunnelling barriers and gate electrodes in planar dopant devices and pave the way towards reliable quantum device fabrication at the atomic scale. Support from EU grants PAMS, SiSpin, SiAM and from Swiss NCCR QSIT is gratefully acknowledged.

  5. Growth of Methanogenic Bacteria in Pure Culture with 2-Propanol and Other Alcohols as Hydrogen Donors

    PubMed Central

    Widdel, Friedrich

    1986-01-01

    Two types of mesophilic, methanogenic bacteria were isolated in pure culture from anaerobic freshwater and marine mud with 2-propanol as the hydrogen donor. The freshwater strain (SK) was a Methanospirillum species, the marine, salt-requiring strain (CV), which had irregular coccoid cells, resembled Methanogenium sp. Stoichiometric measurements revealed formation of 1 mol of CH4 by CO2 reduction, with 4 mol of 2-propanol being converted to acetone. In addition to 2-propanol, the isolates used 2-butanol, H2, or formate but not methanol or polyols. Acetate did not serve as an energy substrate but was necessary as a carbon source. Strain CV also oxidized ethanol or 1-propanol to acetate or propionate, respectively; growth on the latter alcohols was slower, but final cell densities were about threefold higher than on 2-propanol. Both strains grew well in defined, bicarbonate-buffered, sulfide-reduced media. For cultivation of strain CV, additions of biotin, vitamin B12, and tungstate were necessary. The newly isolated strains are the first methanogens that were shown to grow in pure culture with alcohols other than methanol. Bioenergetic aspects of secondary and primary alcohol utilization by methanogens are discussed. Images PMID:16347050

  6. Unique Reactivity Patterns Catalyzed by Internal Lewis Acid Assisted Hydrogen Bond Donors

    NASA Astrophysics Data System (ADS)

    Auvil, Tyler Jay

    The advancement of hydrogen bond donor (HBD) organocatalysis has been inhibited by a number of challenges. Conventional HBDs suffer from high catalyst loadings and operate in only limited types of reactions, typically the activation of 1,2- and 1,4-acceptors for nucleophilic attack. One strategy to address the shortcomings of HBD catalysis is to design innovative catalysts with improved reactivity. To this end, boronate ureas have been developed as a new family of enhanced HBD catalysts that enable useful new reactivity patterns. Boronate ureas are easily-accessible, small organic molecules that benefit from improved catalytic abilities plausibly due to internal coordination of the urea carbonyl to a strategically placed Lewis acid. Optimization of the boronate urea scaffold has revealed their enhanced catalytic activity, enabling new directions in HBD catalysis. The discovery of boronate ureas has allowed for the unveiling of new HBD activation modes, providing unique reactivity patterns that are inaccessible with conventional HBD catalysts. Among these reactivity patterns is the activation of strained nitrocyclopropane carboxylates for nucleophilic ring-opening reactions, which affords a swift route to access gamma-amino-alpha-nitroester building blocks. The ring-opening method was highlighted by its utilization in the total synthesis of a CB-1 receptor inverse agonist, which was recently patented by Eli Lilly. Additionally, boronate ureas can elicit carbene-like reactivity from alpha-diazocarbonyl compounds, allowing for organocatalytic heteroatom-hydrogen insertions reactions, the first of their kind. The boronate urea activation of alpha-nitrodiazoesters has permitted the development of an unsymmetric double alpha-arylation process, affording a synthetically challenging motif in a single flask. The alpha-arylation reaction proceeds through a conceptually novel organocatalytic transient N--H insertion process, employing anilines as carbene activators. The use

  7. Fundamental Kinetics of Supercritical Coal Liquefaction: Effect of Catalysts and Hydrogen-Donor Solvents.

    SciTech Connect

    McCoy, B.J.; Smith, J.M.

    1997-07-21

    Most research on polymer degradation is for single polymers, even though the thermal decomposition of polymer mixtures is of interest both practically and theoretically. Polymer degradation rates depend on the mixture type, and adding a polymer can increase, decrease, or leave unchanged the degradation rate of the first polymer. We show how distribution-kinetics theory, based on molecular-weight distributions (MWDs), provides expressions for degradation rates of binary polymer mixtures. The approach accounts for initiation, termination, hydrogen abstraction, and radical chain scission in the governing equations for MWDS. Molecular-weight moments yield expressions for molar and mass concentrations and rate coefficients for combinations of random and chain-end scission. Experimental data show the concentration effect of poly((x-methyl styrene)) (PAMS) on the degradation of polystyrene dissolved in mineral oil at 275 {degrees}C in a batch reactor. Samples analyzed by gel permeation chromatography yielded the time evolution of the MD. The results indicated that, owing to the interaction of mixed radicals with polymer by hydrogen abstraction, polystyrene degradation rate decreases with increasing PAMS concentration.

  8. Synthetic and mechanistic studies of metal-free transfer hydrogenations applying polarized olefins as hydrogen acceptors and amine borane adducts as hydrogen donors.

    PubMed

    Yang, Xianghua; Fox, Thomas; Berke, Heinz

    2012-01-28

    Metal-free transfer hydrogenation of polarized olefins (RR'C=CEE': R, R' = H or organyl, E, E' = CN or CO(2)Me) using amine borane adducts RR'NH-BH(3) (R = R' = H, AB; R = Me, R' = H, MAB; R = (t)Bu, R' = H, tBAB; R = R' = Me, DMAB) as hydrogen donors, were studied by means of in situ NMR spectroscopy. Deuterium kinetic isotope effects and the traced hydroboration intermediate revealed that the double H transfer process occurred regio-specifically in two steps with hydride before proton transfer characteristics. Studies on substituent effects and Hammett correlation indicated that the rate determining step of the H(N) transfer is in agreement with a concerted transition state. The very reactive intermediate [NH(2)=BH(2)] generated from AB was trapped by addition of cyclohexene into the reaction mixture forming Cy(2)BNH(2). The final product borazine (BHNH)(3) is assumed to be formed by dehydrocoupling of [NH(2)=BH(2)] or its solvent stabilized derivative [NH(2)=BH(2)]-(solvent), rather than by dehydrogenation of cyclotriborazane (BH(2)NH(2))(3) which is the trimerization product of [NH(2)=BH(2)]. PMID:22124505

  9. Two different hydrogen bond donor ligands together: a selectivity improvement in organometallic {Re(CO)3} anion hosts.

    PubMed

    Ion, Laura; Nieto, Sonia; Pérez, Julio; Riera, Lucía; Riera, Víctor; Díaz, Jesús; López, Ramón; Anderson, Kirsty M; Steed, Jonathan W

    2011-09-01

    Rhenium(I) compounds [Re(CO)(3)(Hdmpz)(2)(ampy)]BAr'(4) and [Re(CO)(3)(N-MeIm)(2)(ampy)]BAr'(4) (Hdmpz = 3,5-dimethylpyrazole, N-MeIm = N-methylimidazole, ampy = 2-aminopyridine or 3-aminopyridine) have been prepared stepwise as the sole reaction products in good yields. The cationic complexes feature two different types of hydrogen bond donor ligands, and their anion binding behavior has been studied both in solution and in the solid state. Compounds with 2-ampy ligands are labile in the presence of nearly all of the anions tested. The X-ray structure of the complex [Re(CO)(3)(Hdmpz)(2)(ampy)](+) (2) shows that the 2-ampy ligand is metal-coordinated through the amino group, a fact that can be responsible for its labile character. The 3-ampy derivatives (coordinated through the pyridinic nitrogen atom) are stable toward the addition of several anions and are more selective anion hosts than their tris(pyrazole) or tris(imidazole) counterparts. This selectivity is higher for compound [Re(CO)(3)(N-MeIm)(2)(MeNA)]BAr'(4) (5·BAr'(4), MeNA = N-methylnicotinamide) that features an amido moiety, which is a better hydrogen bond donor than the amino group. Some of the receptor-anion adducts have been characterized in the solid state by X-ray diffraction, showing that both types of hydrogen bond donor ligands of the cationic receptor participate in the interaction with the anion hosts. DFT calculations suggest that coordination of the ampy ligands is more favorable through the amino group only for the cationic complex 2, as a consequence of the existence of a strong intramolecular hydrogen bond. In all other cases, the pyridinic coordination is clearly favored. PMID:21834508

  10. General quantitative model for coal liquefaction kinetics: the thermal cleavage/hydrogen donor capping mechanism. [59 references

    SciTech Connect

    Gangwer, T

    1980-01-01

    A mechanism for coal liquefaction, based on the concept of thermal cleavage-hydrogen capping donor complexes, is proposed and the quantitative agreement between the derived rate laws and the kinetic data obtained from fifteen publications is presented. The mechanism provides rate laws which describe the preasphaltene, asphaltene, oil and gas time/yield curves for the coal liquefaction process. A simplistic dissolution model is presented and used to relate the proposed mechanism to the experimentally observed products. Based on the quality of the mechanistic fit to the reported coal liquefaction systems, which cover a diverse range of reaction conditions, coal types and donor solvent compositions, it is proposed that the donor solvent/thermal bond cleavage/hydrogen capping mechanism provides a good, quantitative description of the rate limiting process. Interpretation of the rate constant/temperature dependencies in terms of transition state theory indicates formation of the activated complex can involve either physically or chemically controlled steps. A uniform free energy of activation of 52 kcal was found for the diverse liquefaction systems indicating a common transition state describes the reactions. Thus the proposed mechanism unifies the diverse liquefaction kinetic data by using a set of uniform reaction sequences, which have a common transition state, to describe the conversion chemistry. The mechanism thereby creates a common base for intercomparison, interpretation and evaluation of coal conversion for the broad range of processes currently being investigated in the liquefaction field.

  11. Additive cardioprotection by pharmacological postconditioning with hydrogen sulfide and nitric oxide donors in mouse heart: S-sulfhydration vs. S-nitrosylation.

    PubMed

    Sun, Junhui; Aponte, Angel M; Menazza, Sara; Gucek, Marjan; Steenbergen, Charles; Murphy, Elizabeth

    2016-05-01

    Hydrogen sulfide (H2S), as a gaseous signalling molecule, has been found to play important roles in postconditioning (PostC)-induced cardioprotection. Similar to nitric oxide (NO)-mediated protein S-nitrosylation (SNO), recent studies suggest that H2S could regulate protein function through another redox-based post-translational modification on protein cysteine residue(s), i.e. S-sulfhydration (SSH). In this study, we examined whether there are changes in protein SSH associated with cardioprotection induced by treatment with H2S on reperfusion. In addition, we also examined whether there is cross talk between H2S and NO. Compared with control, treatment on reperfusion with NaHS (H2S donor, 100 µmol/L) significantly reduced post-ischaemic contractile dysfunction and infarct size. A comparable cardioprotective effect could be also achieved by reperfusion treatment with SNAP (NO donor, 10 µmol/L). Interestingly, simultaneous reperfusion with both donors had an additive protective effect. In addition, C-PTIO (NO scavenger, 20 µmol/L) eliminated the protection induced by NaHS and also the additive protection by SNAP + NaHS together. Using a modified biotin switch method, we observed a small increase in SSH following NaHS treatment on reperfusion. We also found that NaHS treatment on reperfusion increases SNO to a level comparable to that with SNAP treatment. In addition, there was an additive increase in SNO but not SSH when SNAP and NaHS were added together at reperfusion. Thus, part of the benefit of NaHS is an increase in SNO, and the magnitude of the protective effect is related to the magnitude of the increase in SNO. PMID:26907390

  12. Enantio- and periselective nitroalkene Diels-Alder reactions catalyzed by helical-chiral hydrogen bond donor catalysts.

    PubMed

    Peng, Zhili; Narcis, Maurice J; Takenaka, Norito

    2013-01-01

    Helical-chiral double hydrogen bond donor catalysts promote the nitroalkene Diels-Alder reaction in an enantio- and periselective manner. This represents the first asymmetric catalytic nitroalkene Diels-Alder reaction via LUMO-lowering catalysis. To gain an insight into this new process, the substrate scope of our catalyst was investigated by exploiting readily available 5-substituted pentamethylcyclopentadienes. The catalyst was found to tolerate dienes with different steric demands as well as dienes substituted with heteroatoms. The synthetic utility of 5-substituted pentamethylcyclopentadienes is rather limited, and thus we have developed a three-step route to 1,4,5,5-tetrasubstituted cyclopentadienes from commercially available ketones. PMID:23966083

  13. A method for controlling hydrogen sulfide in water by adding solid phase oxygen.

    PubMed

    Chang, Yu-Jie; Chang, Yi-Tang; Chen, Hsi-Jien

    2007-01-01

    This work evaluates the addition of solid phase oxygen, a magnesium peroxide (MgO(2)) formulation manufactured by Regenesis (oxygen-releasing compounds, ORC), to inhibit the production of hydrogen sulfide (H(2)S) in an SRB-enriched environment. The initial rate of release of oxygen by the ORC was determined over a short period by adding sodium sulfite (Na(2)SO(3)), which was a novel approach developed for this study. The ability of ORCs to control H(2)S by releasing oxygen was evaluated in a bench-scale column containing cultured sulfate reducing bacteria (SRB). After a series of batch tests, 0.4% ORC was found to be able to inhibit the formation of H(2)S for more than 40 days. In comparison, the concentration of H(2)S dropped from 20 mg S/L to 0.05 mg S/L immediately after 0.1% hydrogen peroxide (H(2)O(2)) was added, but began to recover just four days later. Thus, H(2)O(2) does not seem to be able to inhibit the production of sulfide for an extended period of time. By providing long-term inhibition of the SRB population, ORC provides a good alternative means of controlling the production of H(2)S in water. PMID:16439114

  14. Mechanism of formation of ultrashallow thermal donors in carbon-doped oxygen-rich monocrystalline silicon preannealed to introduce hydrogen

    NASA Astrophysics Data System (ADS)

    Hara, Akito; Awano, Teruyoshi

    2015-10-01

    We previously reported on ultrashallow thermal donors (USTDs) in carbon-doped oxygen-containing monocrystalline silicon (Czochralski-grown, CZ-Si) crystals that were preannealed to introduce hydrogen at 1300 °C, and then annealed at 480 °C. In this study, the formation mechanism of the USTDs was evaluated. It was observed that an increase in the intensity of UTSDs leads to a reduction in that of hydrogen-related shallow thermal donors [STD(H)s], and the sum of the area intensities of the lines in the transmission spectra of USTDs and STD(H)s is nearly constant when the silicon crystals are annealed for longer than 10 h at 480 °C. We also found some thermally activated processes linked to the formation of USTDs. We thus conclude that the mechanism is composed of the high-speed formation of STD(H)s in the first stage and carbon modulation of the electronic structure of STD(H)s in the second stage.

  15. Inhibitory Action Of Novel Hydrogen Sulfide Donors On Bovine Isolated Posterior Ciliary Arteries

    PubMed Central

    Kulkarni-Chitnis, Madhura; Njie-Mbye, Ya Fatou; Mitchell, Leah; Robinson, Jenaye; Whiteman, Mathew; Wood, Mark E.; Opere, Catherine A.; Ohia, Sunny E.

    2015-01-01

    In the present study, we investigate the inhibitory effect of novel H2S donors, AP67 and AP72 on isolated bovine posterior ciliary arteries (PCAs) under conditions of tone induced by an adrenoceptor agonist. Furthermore, we examined the possible mechanisms underlying the AP67- and AP72-induced relaxations. Isolated bovine PCA were set up for measurement of isometric tension in organ baths containing oxygenated Krebs solution. The relaxant action of H2S donors was studied on phenylephrine-induced tone in the absence or presence of enzyme inhibitors for the following pathways: cyclooxygenase (COX); H2S; nitric oxide and the ATP-sensitive K+ (KATP) channel. The H2S donors, NaHS (1 nM - 10 μM), AP67 (1 nM - 10 μM) and AP72 (10 nM -1 μM) elicited a concentration-dependent relaxation of phenylephrine-induced tone in isolated bovine PCA. While the COX inhibitor, flurbiprofen (3 μM) blocked significantly (p < 0.05) the inhibitory response elicited by AP67, it had no effect on relaxations induced by NaHS and AP72. Both aminooxyacetic acid (30 μM) and propargylglycine (1 mM), enzyme inhibitors of H2S biosynthesis caused significant (p < 0.05) rightward shifts in the concentration-response curve to AP67 and AP72. Furthermore, the KATP channel antagonist, glibenclamide (300 μM) and the NO synthase inhibitor, L-NAME (100 μM) significantly attenuated (p < 0.05) the relaxation effect induced by AP67 and AP72 on PCA. We conclude that H2S donors can relax pre-contracted isolated bovine PCA, an effect dependent on endogenous production of H2S. The inhibitory action of only AP67 on pre-contracted PCA may involve the production of inhibitory endogenous prostanoids. Furthermore, the observed inhibitory action of H2S donors on PCA may depend on the endogenous biosynthesis of NO and by an action of KATP channels. PMID:25845295

  16. The donor OH stretching-libration dynamics of hydrogen-bonded methanol dimers in cryogenic matrices.

    PubMed

    Heger, M; Andersen, J; Suhm, M A; Wugt Larsen, R

    2016-02-01

    FTIR spectra of the methanol dimer trapped in neon matrices are presented. The fundamental, overtone and combination bands involving the donor OH libration and stretching motions were observed in order to extract relevant anharmonicity constants. We find a stretching-libration coupling constant of +43(5) cm(-1) and a diagonal librational anharmonicity constant of -71(5) cm(-1). The spectra are compared to a number of VPT2 calculations and a torsionally localized monomer model in order to enhance previous explanations of the observable OH stretching red-shift upon dimerization. PMID:26763101

  17. Diamagnetic susceptibility of an off-center hydrogenic donor in pyramid-like and cone-like quantum dots

    NASA Astrophysics Data System (ADS)

    Avazzadeh, Z.; Bahramiyan, H.; Khordad, R.; Mohammadi, S. A.

    2016-04-01

    In this study, the diamagnetic susceptibility of an off-center hydrogenic donor impurity confined by pyramid and cone-like quantum dots has been investigated. To this end, the finite-element method and the Arnoldi algorithm are used to find energy eigenvalues and eigenvectors of the systems. Then, the effect of impurity position and dot size has been investigated on the diamagnetic susceptibility. We have found that the diamagnetic susceptibility has a maximum around the impurity position 4nm for two quantum dots. The diamagnetic susceptibility in the cone-like quantum dot is smaller than that in the pyramid quantum dot. Numerical studies reveal that the diamagnetic susceptibility depends strongly on the geometry of the dot.

  18. Rotating-frame nuclear magnetic resonance study of the distinct dynamics of hydrogen donors in ZnO

    NASA Astrophysics Data System (ADS)

    Kue Park, Jun; Won Lee, Kyu; Eui Lee, Cheol

    2013-07-01

    The rotating-frame spin-lattice relaxation of two types of the hydrogen donors was well distinguished in the 1H nuclear magnetic resonance measurements in a sol-gel prepared ZnO system, providing a unique opportunity to study the distinct proton dynamics. Our study indicates interconversion of the interstitial H (Hi). The population of the mobile Hi showed decrease above ˜370 K, apparently being trapping into the oxygen vacancies resulting in the more stable oxygen-substitutional H (HO). The activation barrier for migration of Hi and the binding energy of HO were found to be 0.27 eV and 0.51 eV, respectively.

  19. Hydrogen Sulfide Donor Protects Porcine Oocytes against Aging and Improves the Developmental Potential of Aged Porcine Oocytes

    PubMed Central

    Krejcova, Tereza; Smelcova, Miroslava; Petr, Jaroslav; Bodart, Jean-Francois; Sedmikova, Marketa; Nevoral, Jan; Dvorakova, Marketa; Vyskocilova, Alena; Weingartova, Ivona; Kucerova-Chrpova, Veronika; Chmelikova, Eva; Tumova, Lenka; Jilek, Frantisek

    2015-01-01

    Porcine oocytes that have matured in in vitro conditions undergo the process of aging during prolonged cultivation, which is manifested by spontaneous parthenogenetic activation, lysis or fragmentation of aged oocytes. This study focused on the role of hydrogen sulfide (H2S) in the process of porcine oocyte aging. H2S is a gaseous signaling molecule and is produced endogenously by the enzymes cystathionine-β-synthase (CBS), cystathionine-γ-lyase (CSE) and 3-mercaptopyruvate sulfurtransferase (MPST). We demonstrated that H2S-producing enzymes are active in porcine oocytes and that a statistically significant decline in endogenous H2S production occurs during the first day of aging. Inhibition of these enzymes accelerates signs of aging in oocytes and significantly increases the ratio of fragmented oocytes. The presence of exogenous H2S from a donor (Na2S.9H2O) significantly suppressed the manifestations of aging, reversed the effects of inhibitors and resulted in the complete suppression of oocyte fragmentation. Cultivation of aging oocytes in the presence of H2S donor positively affected their subsequent embryonic development following parthenogenetic activation. Although no unambiguous effects of exogenous H2S on MPF and MAPK activities were detected and the intracellular mechanism underlying H2S activity remains unclear, our study clearly demonstrates the role of H2S in the regulation of porcine oocyte aging. PMID:25615598

  20. Ab initio theoretical study of hydrogen and its interaction with boron acceptors and nitrogen donors in single-wall silicon carbide nanotubes

    NASA Astrophysics Data System (ADS)

    Gali, A.

    2007-02-01

    Silicon carbide nanotubes have a great potential for biological applications. It is of interest to explore the electronic properties of these nanotubes, and how those are modified in the presence of impurities. Hydrogen is a common impurity that can appear during the growth of silicon carbide nanotubes or in the environment. In this paper we studied the properties of one and two hydrogen atoms in armchair and zigzag silicon carbide nanotubes by ab initio supercell calculations beyond the standard density functional theory. We found that a single hydrogen atom is an amphoteric defect: it can act as a donor as well as an acceptor, depending on the adsorption site. However, both sites are nearly equally stable; therefore these defects compensate each other in SiC nanotube semiconductors. We found that hydrogen can absorb onto SiC nanotubes when atomic hydrogen is present in the environment. In addition, we investigated the incorporation of hydrogen by applying BH and NH molecules in the environment of SiC nanotubes. The simulations predict that boron dissolves into SiC nanotubes together with hydrogen; thus boron can be used to raise the concentration of hydrogen in SiC nanotubes. Nitrogen is also incorporated with hydrogen. We predict that the shallow boron acceptor and the nitrogen donor may be activated in these processes.

  1. Adaptation of a Small-Molecule Hydrogen-Bond Donor Catalyst to an Enantioselective Hetero-Diels–Alder Reaction Hypothesized for Brevianamide Biosynthesis

    PubMed Central

    2015-01-01

    Chiral diamine-derived hydrogen-bond donors were evaluated for their ability to effect stereocontrol in an intramolecular hetero-Diels–Alder (HDA) reaction hypothesized in the biosynthesis of brevianamides A and B. Collectively, these results provide proof of principle that small-molecule hydrogen-bond catalysis, if even based on a hypothetical biosynthesis construct, holds significant potential within enantioselective natural product synthesis. PMID:25697748

  2. Peroxide test strips detect added hydrogen peroxide in raw milk at levels affecting bacterial load.

    PubMed

    Martin, Nicole H; Friedlander, Adam; Mok, Allen; Kent, David; Wiedmann, Martin; Boor, Kathryn J

    2014-10-01

    Hydrogen peroxide (H2O2) has a long-established history of use as a preservative in milk worldwide. The use of H2O2 to activate the inherent lactoperoxidase enzyme system has dramatically improved the quality of raw dairy products in areas in which cooling is not widely available. In the United States, however, where refrigeration is widely available, the addition of H2O2 to milk is not permitted, with the exception of certain applications prior to cheesemaking and during the preparation of modified whey. Due to the relatively quick deterioration of H2O2 in fluid milk, the detection of raw milk adulterated with the compound can be challenging. In this study we evaluated (i) total aerobic bacterial counts and (ii) ability of peroxide test strips to detect H2O2 in raw milk with various concentrations (0, 100, 300, 500, 700, and 900 ppm) of added H2O2, incubated at both 6 and 21°C for 0, 24, and 48 h. Results showed that at both 6 and 21°C the H2O2 concentration and time had a significant effect on bacterial loads in raw milk. Additionally, commercially available test strips were able to detect H2O2 in raw milk, with predicted probability of >90%, immediately after addition and after 24 and 48 h for the higher concentrations used, offering a viable method for detecting raw milk adulteration with H2O2. PMID:25285503

  3. Ammonia synthesis using a stable electride as an electron donor and reversible hydrogen store

    NASA Astrophysics Data System (ADS)

    Kitano, Masaaki; Inoue, Yasunori; Yamazaki, Youhei; Hayashi, Fumitaka; Kanbara, Shinji; Matsuishi, Satoru; Yokoyama, Toshiharu; Kim, Sung-Wng; Hara, Michikazu; Hosono, Hideo

    2012-11-01

    Industrially, the artificial fixation of atmospheric nitrogen to ammonia is carried out using the Haber-Bosch process, but this process requires high temperatures and pressures, and consumes more than 1% of the world's power production. Therefore the search is on for a more environmentally benign process that occurs under milder conditions. Here, we report that a Ru-loaded electride [Ca24Al28O64]4+(e-)4 (Ru/C12A7:e-), which has high electron-donating power and chemical stability, works as an efficient catalyst for ammonia synthesis. Highly efficient ammonia synthesis is achieved with a catalytic activity that is an order of magnitude greater than those of other previously reported Ru-loaded catalysts and with almost half the reaction activation energy. Kinetic analysis with infrared spectroscopy reveals that C12A7:e- markedly enhances N2 dissociation on Ru by the back donation of electrons and that the poisoning of ruthenium surfaces by hydrogen adatoms can be suppressed effectively because of the ability of C12A7:e- to store hydrogen reversibly.

  4. Ammonia synthesis using a stable electride as an electron donor and reversible hydrogen store.

    PubMed

    Kitano, Masaaki; Inoue, Yasunori; Yamazaki, Youhei; Hayashi, Fumitaka; Kanbara, Shinji; Matsuishi, Satoru; Yokoyama, Toshiharu; Kim, Sung-Wng; Hara, Michikazu; Hosono, Hideo

    2012-11-01

    Industrially, the artificial fixation of atmospheric nitrogen to ammonia is carried out using the Haber-Bosch process, but this process requires high temperatures and pressures, and consumes more than 1% of the world's power production. Therefore the search is on for a more environmentally benign process that occurs under milder conditions. Here, we report that a Ru-loaded electride [Ca(24)Al(28)O(64)](4+)(e(-))(4) (Ru/C12A7:e(-)), which has high electron-donating power and chemical stability, works as an efficient catalyst for ammonia synthesis. Highly efficient ammonia synthesis is achieved with a catalytic activity that is an order of magnitude greater than those of other previously reported Ru-loaded catalysts and with almost half the reaction activation energy. Kinetic analysis with infrared spectroscopy reveals that C12A7:e(-) markedly enhances N(2) dissociation on Ru by the back donation of electrons and that the poisoning of ruthenium surfaces by hydrogen adatoms can be suppressed effectively because of the ability of C12A7:e(-) to store hydrogen reversibly. PMID:23089869

  5. Complete bromate and nitrate reduction using hydrogen as the sole electron donor in a rotating biofilm-electrode reactor.

    PubMed

    Zhong, Yu; Li, Xin; Yang, Qi; Wang, Dongbo; Yao, Fubing; Li, Xiaoming; Zhao, Jianwei; Xu, Qiuxiang; Zhang, Chang; Zeng, Guangming

    2016-04-15

    Simultaneous reduction of bromate and nitrate was investigated using a rotating biofilm-electrode reactor (RBER) with graphite carbon (GC) rods as anode and activated carbon fiber (ACF) bonded with steel ring as cathode. In RBER, the community of denitrifying bacteria immobilized on the cathode surface could completely utilize hydrogen (H2) as the electron donor, which was internally produced by the electrolysis of water. The short-term test confirmed that the RBER system could reduce 150-800μg/L bromate to below 10μg/L under autotrophic conditions. The reduced bromate was considered to be roughly equivalent to the amount of bromide in effluent, indicating that bromate was completely reduced to bromide without accumulation of by-products. The long-term test (over 120 days) showed that the removal fluxes of bromate and nitrate could be improved by increasing the electric current and decreasing the hydraulic retention time (HRT). But nitrite in effluent was significantly accumulated when the electric current was beyond 10mA and the HRT was less than 6h. The maximum bromate reduction rate estimated by the Monod equation was 109.12μg/Lh when the electric current was 10mA and HRT was 12h. It was proposed that the electron transfer process in RBER produced H2 on the surface of the ACF cathode, and the microbial cultures attached closely on the cathode which could completely utilize H2 as electron donors for reduction of bromate and nitrate. PMID:26775102

  6. Predicting the Reactivity of Hydride Donors in Water: Thermodynamic Constants for Hydrogen

    SciTech Connect

    Connelly, Samantha J.; Wiedner, Eric S.; Appel, Aaron M.

    2015-01-01

    Chemical reactivity of hydride complexes can be predicted by comparing bond strengths for homolytic and heterolytic cleavage of bonds to hydrogen. To determine these bond strengths, thermodynamic constants for H+, H•, H–, and H2 are essential and need to be used uniformly to enable the prediction of reactivity and equilibria. One of the largest challenges is quantifying the stability of solvated H– in water, which is discussed. Due to discrepancies in the literature for the constants used in water, we propose the use of a set of self-consistent constants with convenient standard states. The work was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences & Biosciences.

  7. Effect of hydrogen addition on the deposition of titanium nitride thin films in nitrogen added argon magnetron plasma

    NASA Astrophysics Data System (ADS)

    Saikia, P.; Bhuyan, H.; Diaz-Droguett, D. E.; Guzman, F.; Mändl, S.; Saikia, B. K.; Favre, M.; Maze, J. R.; Wyndham, E.

    2016-06-01

    The properties and performance of thin films deposited by plasma assisted processes are closely related to their manufacturing techniques and processes. The objective of the current study is to investigate the modification of plasma parameters occurring during hydrogen addition in N2  +  Ar magnetron plasma used for titanium nitride thin film deposition, and to correlate the measured properties of the deposited thin film with the bulk plasma parameters of the magnetron discharge. From the Langmuir probe measurements, it was observed that the addition of hydrogen led to a decrease of electron density from 8.6 to 6.2  ×  (1014 m‑3) and a corresponding increase of electron temperature from 6.30 to 6.74 eV. The optical emission spectroscopy study reveals that with addition of hydrogen, the density of argon ions decreases. The various positive ion species involving hydrogen are found to increase with increase of hydrogen partial pressure in the chamber. The thin films deposited were characterized using standard surface diagnostic tools such as x-ray photoelectron spectroscopy (XPS), secondary ion mass spectrometry (SIMS), x-ray diffraction (XRD), Raman spectroscopy (RS), scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS). Although it was possible to deposit thin films of titanium nitride with hydrogen addition in nitrogen added argon magnetron plasma, the quality of the thin films deteriorates with higher hydrogen partial pressures.

  8. Molecular dynamics study of the encapsulation capability of a PCL-PEO based block copolymer for hydrophobic drugs with different spatial distributions of hydrogen bond donors and acceptors.

    PubMed

    Patel, Sarthak K; Lavasanifar, Afsaneh; Choi, Phillip

    2010-03-01

    Molecular dynamics simulation was used to study the potential of using a block copolymer containing three poly(epsilon-caprolactone) (PCL) blocks of equal length connected to one end of a poly(ethylene oxide) (PEO) block, designated as PEO-b-3PCL, to encapsulate two classes of hydrophobic drugs with distinctively different molecular structures. In particular, the first class of drugs consisted of two cucurbitacin drugs (CuB and CuI) that contain multiple hydrogen bond donors and acceptors evenly distributed on their molecules while the other class of drugs (fenofibrate and nimodipine) contain essentially only clustered hydrogen bond acceptors. In the case of cucurbitacin drugs, the results showed that PEO-b-3PCL lowered the Flory-Huggins interaction parameters (chi) considerably (i.e., increased the drug solubility) compared to the linear di-block copolymer PEO-b-PCL with the same PCL/PEO (w/w) ratio of 1.0. However, the opposite effect was observed for fenofibrate and nimodipine. Analysis of the intermolecular interactions indicates that the number of hydrogen bonds formed between the three PCL blocks and cucurbitacin drugs is significantly higher than that of the linear di-block copolymer. On the other hand, owing to the absence of hydrogen bond donors and the clustering of the hydrogen bond acceptors on the fenofibrate and nimodipine molecules, this significantly reduces the number of hydrogen bonds formed in the multi-PCL block environment, leading to unfavourable chi values. The findings of the present work suggest that multi-hydrophobic block architecture could potentially increase the drug loading for hydrophobic drugs with structures containing evenly distributed multiple hydrogen bond donors and acceptors. PMID:19962756

  9. Pine Pyrolysis Vapor Phase Upgrading Over ZSM-5 Catalyst: Effect of Temperature, Hot Gas Filtration, and Hydrogen Donor Molecule on the Rate of Deactivation of Catalyst

    SciTech Connect

    Mukarakate, C.; Zhang, X.; Nimlos, M.; Robichaud, D.; Donohoe, B.

    2013-01-01

    The conversion of primary vapors from pine pyrolysis over a ZSM-5 catalyst was characterized using a micro-reactor coupled to a molecular beam mass spectrometer (MBMS) to allow on-line measurement of the upgraded vapors. This micro-reacor-MBMS system was used to investigate the effects of hot gas filtration, temperature and hydrogen donor molecules on the rate of deactivation of the UPV2 catalyst. Our results show that the life of catalyst is significantly improved by using better filtration. Temperature had an effect on both product distribution and catalyst deactivation. The hydrogen donor molecules (HDM) used in this study show better reduction in catalyst deactivation rates at high temperatures.

  10. Tetrahydroxydiboron-Mediated Palladium-Catalyzed Transfer Hydrogenation and Deuteriation of Alkenes and Alkynes Using Water as the Stoichiometric H or D Atom Donor.

    PubMed

    Cummings, Steven P; Le, Thanh-Ngoc; Fernandez, Gilberto E; Quiambao, Lorenzo G; Stokes, Benjamin J

    2016-05-18

    There are few examples of catalytic transfer hydrogenations of simple alkenes and alkynes that use water as a stoichiometric H or D atom donor. We have found that diboron reagents efficiently mediate the transfer of H or D atoms from water directly onto unsaturated C-C bonds using a palladium catalyst. This reaction is conducted on a broad variety of alkenes and alkynes at ambient temperature, and boric acid is the sole byproduct. Mechanistic experiments suggest that this reaction is made possible by a hydrogen atom transfer from water that generates a Pd-hydride intermediate. Importantly, complete deuterium incorporation from stoichiometric D2O has also been achieved. PMID:27135185

  11. Organocatalytic asymmetric Henry reaction of 1H-pyrrole-2,3-diones with bifunctional amine-thiourea catalysts bearing multiple hydrogen-bond donors.

    PubMed

    Zhang, Ming-Liang; Yue, Deng-Feng; Wang, Zhen-Hua; Luo, Yuan; Xu, Xiao-Ying; Zhang, Xiao-Mei; Yuan, Wei-Cheng

    2016-01-01

    For the first time, a catalytic asymmetric Henry reaction of 1H-pyrrole-2,3-diones was achieved with a chiral bifunctional amine-thiourea as a catalyst possessing multiple hydrogen-bond donors. With this developed method, a range of 3-hydroxy-3-nitromethyl-1H-pyrrol-2(3H)-ones bearing quaternary stereocenters were obtained in acceptable yield (up to 75%) and enantioselectivity (up to 73% ee). PMID:26977188

  12. NAD(P)H-Independent Asymmetric C=C Bond Reduction Catalyzed by Ene Reductases by Using Artificial Co-substrates as the Hydrogen Donor

    PubMed Central

    Winkler, Christoph K; Clay, Dorina; Entner, Marcello; Plank, Markus; Faber, Kurt

    2014-01-01

    To develop a nicotinamide-independent single flavoenzyme system for the asymmetric bioreduction of C=C bonds, four types of hydrogen donor, encompassing more than 50 candidates, were investigated. Six highly potent, cheap, and commercially available co-substrates were identified that (under the optimized conditions) resulted in conversions and enantioselectivities comparable with, or even superior to, those obtained with traditional two-enzyme nicotinamide adenine dinucleotide phosphate (NAD(P)H)-recycling systems. PMID:24382795

  13. Organocatalytic asymmetric Henry reaction of 1H-pyrrole-2,3-diones with bifunctional amine-thiourea catalysts bearing multiple hydrogen-bond donors

    PubMed Central

    Zhang, Ming-Liang; Yue, Deng-Feng; Wang, Zhen-Hua; Luo, Yuan; Zhang, Xiao-Mei

    2016-01-01

    Summary For the first time, a catalytic asymmetric Henry reaction of 1H-pyrrole-2,3-diones was achieved with a chiral bifunctional amine-thiourea as a catalyst possessing multiple hydrogen-bond donors. With this developed method, a range of 3-hydroxy-3-nitromethyl-1H-pyrrol-2(3H)-ones bearing quaternary stereocenters were obtained in acceptable yield (up to 75%) and enantioselectivity (up to 73% ee). PMID:26977188

  14. A Comparative PCET Study of a Donor-Acceptor Pair Linked by Ionized and Non-ionized Asymmetric Hydrogen-Bonded Interfaces

    PubMed Central

    Young, Elizabeth R.; Rosenthal, Joel; Hodgkiss, Justin M.

    2012-01-01

    A Zn(II) porphyrin-amidinium is the excited state electron donor (D) to a naphthalene diimide acceptor (A) appended with either a carboxylate or sulfonate functionality. The two-point hydrogen bond (---[H+]---) formed between the amidinium and carboxylate or sulfonate establishes a proton-coupled electron transfer (PCET) pathway for charge transfer. The two D---[H+]---A assemblies differ only by the proton configuration within the hydrogen bonding interface. Specifically, the amidinium transfers a proton to the carboxylate to form a non-ionized amidine-carboxylic acid two-point hydrogen network whereas the amidinium maintains both protons when bound to the sulfonate functionality forming an ionized amidinium-sulfonate two-point hydrogen network. These two interface configurations within the dyads thus allow for a direct comparison of PCET kinetics for the same donor and acceptor juxtaposed by an ionized and non-ionized hydrogen-bonded interface. Analysis of PCET kinetics ascertained from transient absorption and transient emission spectroscopy reveal that the ionized interface is more strongly impacted by the local solvent environment, thus establishing that the initial static configuration of the proton interface is a critical determinant to the kinetics of PCET. PMID:19489645

  15. Chemistry of ruthenium(II) monohydride and dihydride complexes containing pyridyl donor ligands including catalytic ketone H2-hydrogenation.

    PubMed

    Abdur-Rashid, Kamaluddin; Abbel, Robert; Hadzovic, Alen; Lough, Alan J; Morris, Robert H

    2005-04-01

    In this study we determine the changes to the properties of dihydride catalysts for ketone H2-hydrogenation by successively replacing the amine donors in the known dach complex RuH2(PPh3)2(dach) (2a), dach = 1,2-(R,R)-diaminocyclohexane, with one pyridyl group in the corresponding 2-(aminomethyl)pyridine (ampy) complexes RuH2(PPh3)2(ampy) (2b) and with two pyridyl groups in the complexes RuH2(PPh3)2(bipy) (2c) and RuH2(PPh3)2(phen) (2d). The ruthenium monohydride complex, (OC-6-54)-RuHCl(PPh3)2(ampy), (1b with Cl trans to H) was prepared by the addition of 1 equiv of ampy to RuHCl(PPh3)3 in THF. Treatment of the monohydride complex with K[BH(sec-Bu)3] in THF or KOtBu/H2 in toluene resulted in the formation of a mixture of at least two isomers of the highly reactive, air-sensitive ruthenium dihydride complex 2b. One is the cis dihydride (OC-6-14)-2b or more simply c,t-2b with trans PPh3 groups and another is the cis dihydride c,c-2b (OC-6-42) that has PPh3 trans to H and PPh3 trans to N(pyridyl). The isomer c,c-2b slowly converts to c,t-2b in solution. The reaction of 1b with KOtBu under Ar results in the formation of a mixture that includes a complex with an imino ligand HN=CH-2-py while the same reaction under H2 leads to c,c-2b and then c,t-2b. The dach complex c,t-2a, reacts with ampy, 2,2'-bipyridine (bipy), and 1,10-phenanthroline (phen) in refluxing THF to form the substituted cis-dihydride complexes c,t-2b, (OC-6-13)-RuH2(PPh3)2(bipy) (c,t-2c with trans PPh3 groups) and (OC-6-13)-RuH2(PPh3)2(phen), c,t-2d, respectively. The dihydrides containing amino groups and cis-PPh3 groups, i.e., c,c-2a or c,c-2b, are active precatalysts for the H2-hydrogenation of acetophenone (neat or in benzene) under mild reaction conditions, whereas those with trans-PPh3 groups, c,t-2a and c,t-2b are much less active. The combination of ampy complex 1b and KOtBu also provides a catalyst in benzene that is more active than the corresponding dach system. The complexes without amino

  16. Reactivity studies of oxo-Mo(IV) complexes containing potential hydrogen-bond acceptor/donor phenolate ligands.

    PubMed

    Ng, Victor Wee Lin; Taylor, Michelle K; Young, Charles G

    2012-03-01

    Reactivity studies of oxo-Mo(IV) complexes, Tp(iPr)MoO{2-OC(6)H(4)C(O)R-κ(2)O,O'} (R = Me, Et, OMe, OEt, OPh, NHPh), containing chelated hydrogen-bond donor/acceptor phenolate ligands are reported. Hydrolysis/oxidation of Tp(iPr)MoO(2-OC(6)H(4)CO(2)Ph-κ(2)O,O') in the presence of methanol yields tetranuclear [Tp(iPr)MoO(μ-O)(2)MoO](2)(μ-OMe)(2) (1), while condensation of Tp(iPr)MoO{2-OC(6)H(4)C(O)Me-κ(2)O,O'} and methylamine gives the chelated iminophenolate complex, Tp(iPr)MoO{2-OC(6)H(4)C(Me)NMe-κ(2)O,N} (2), rather than the aqua complex, Tp(iPr)MoO{2-OC(6)H(4)C(Me)NMe-κO}(OH(2)). The oxo-Mo(IV) complexes are readily oxidized by dioxygen or hydrogen peroxide to the corresponding cis-dioxo-Mo(VI) complexes, Tp(iPr)MoO(2){2-OC(6)H(4)C(O)R}; in addition, suitable one-electron oxidants, e.g., [FeCp(2)]BF(4) and [N(C(6)H(4)Br)(3)][SbCl(6)], oxidize the complexes to their EPR-active (g(iso) ≈ 1.942) molybdenyl counterparts (3, 4). Molybdenyl complexes such as Tp(iPr)MoOCl{2-OC(6)H(4)C(O)R} (5) and Tp(iPr)MoOCl(2) also form when the complexes react with chlorinated solvents. The ester derivatives (R = OMe, OEt, OPh) react with propylene sulfide to form cis-oxosulfido-Mo(VI) complexes, Tp(iPr)MoOS{2-OC(6)H(4)C(O)R}, that crystallize as dimeric μ-disulfido-Mo(V) species, [Tp(iPr)MoO{2-OC(6)H(4)C(O)R}](2)(μ-S(2)) (6-8). The crystal structures of [Tp(iPr)MoO(μ-O)(2)MoO](2)(μ-OMe)(2), Tp(iPr)MoO{2-OC(6)H(4)C(Me)NMe}, Tp(iPr)MoOCl{2-OC(6)H(4)C(O)NHPh}·{2-HOC(6)H(4)C(O)NHPh}, and [Tp(iPr)MoO{2-OC(6)H(4)C(O)R}](2)(μ-S(2)) (R = OMe, OEt) are reported. PMID:22356251

  17. Exogenous administration of thiosulfate, a donor of hydrogen sulfide, attenuates angiotensin II-induced hypertensive heart disease in rats

    PubMed Central

    Snijder, P M; Frenay, A R; de Boer, R A; Pasch, A; Hillebrands, J L; Leuvenink, H G D; van Goor, H

    2015-01-01

    Background and Purpose Hypertension is an important mediator of cardiac damage and remodelling. Hydrogen sulfide (H2S) is an endogenously produced gasotransmitter with cardioprotective properties. However, it is not yet in clinical use. We, therefore, investigated the protective effects of sodium thiosulfate (STS), a clinically applicable H2S donor substance, in angiotensin II (Ang II)-induced hypertensive cardiac disease in rats. Experimental Approach Male Sprague Dawley rats were infused with Ang II (435 ng kg min−1) or saline (control) for 3 weeks via s.c. placed osmotic minipumps. During these 3 weeks, rats received i.p. injections of either STS, NaHS or vehicle (0.9% NaCl). Key Results Compared with controls, Ang II infusion caused an increase in systolic and diastolic BP with associated cardiac damage as evidenced by cardiac hypertrophy, an increase in atrial natriuretic peptide (ANP) mRNA, cardiac fibrosis and increased oxidative stress. Treatment with NaHS and STS prevented the development of hypertension and the increase in ANP mRNA levels. Furthermore, the degree of cardiac hypertrophy, the extent of histological fibrosis in combination with the expression of profibrotic genes and the levels of oxidative stress were all significantly decreased. Conclusions and Implications Ang II-induced hypertensive cardiac disease can be attenuated by treatment with STS and NaHS. Although BP regulation is the most plausible mechanism of cardiac protection, the antifibrotic and antioxidant properties of released sulfide may also contribute to their effects. Our data show that H2S might be a valuable addition to the already existing antihypertensive and cardioprotective therapies. Linked Articles This article is part of a themed section on Pharmacology of the Gasotransmitters. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue-6 PMID:24962324

  18. Microwave and Quantum Chemical Study of the Hydrazino Group as Proton Donor in Intramolecular Hydrogen Bonding of (2-Fluoroethyl)hydrazine (FCH2CH2NHNH2).

    PubMed

    Møllendal, Harald; Samdal, Svein; Guillemin, Jean-Claude

    2015-09-01

    The microwave spectrum of (2-fluoroethyl)hydrazine (FCH2CH2NHNH2) was studied in the 11-123 GHz spectral region to investigate the ability of the hydrazino group to form intramolecular hydrogen bonds acting as a proton donor. This group can participate both in five-member and in six-member internal hydrogen bonds with the fluorine atom. The spectra of four conformers were assigned, and the rotational and centrifugal distortion constants of these rotameric forms were determined. Two of these conformers have five-member intramolecular hydrogen bonds, while the two other forms are without this interaction. The internal hydrogen bonds in the two hydrogen-bonded forms are assumed to be mainly electrostatic in origin because the N-H and C-F bonds are nearly parallel and the associated bond moments are antiparallel. This is the first example of a gas-phase study of a hydrazine where the hydrazino functional group acts as a proton donor in weak intramolecular hydrogen bonds. Extensive quantum chemical calculations at the B3LYP/cc-pVTZ, MP2/cc-pVTZ, and CCSD/cc-pVQZ levels of theory accompanied and guided the experimental work. These calculations predict the existence of no less than 18 conformers, spanning a CCSD internal energy range of 15.4 kJ/mol. Intramolecular hydrogen bonds are predicted to be present in seven of these conformers. Three of these forms have six-member hydrogen bonds, while four have five-member hydrogen bonds. The three lowest-energy conformers have five-member internal hydrogen bonds. The spectrum of the conformer with the lowest energy was not assigned because it has a very small dipole moment. The CCSD relative energies of the two hydrogen-bonded rotamers whose spectra were assigned are 1.04 and 1.62 kJ/mol, respectively, whereas the relative energies of the two conformers with assigned spectra and no hydrogen bonds have relative energies of 6.46 and 4.89 kJ/mol. PMID:26258892

  19. Controlled energy transfer between isolated donor-acceptor molecules intercalated in thermally self-ensemble two-dimensional hydrogen bonding cages

    NASA Astrophysics Data System (ADS)

    Al Attar, Hameed A.; Monkman, Andrew P.

    2012-12-01

    Thermally assembled hydrogen bonding cages which are neither size nor guest specific have been developed using a poly (vinyl alcohol) (PVA) host. A water-soluble conjugated polymer poly(2,5-bis(3-sulfonatopropoxy)-1,4-phenylene, disodium salt-alt-1,4-phenylene) (PPP-OPSO3) as a donor and tris(2,2-bipyridyl)- ruthenium(II) [Ru(bpy)32+] as an acceptor have been isolated and trapped in such a PVA matrix network. This is a unique system that shows negligible exciton diffusion and the donor and acceptor predominantly interact by a direct single step excitation transfer process (DSSET). Singlet and triplet exciton quenching have been studied. Time-resolved fluorescence lifetime measurement at different acceptor concentrations has enabled us to determine the dimensionality of the energy-transfer process within the PVA scaffold. Our results reveal that the PVA hydrogen bonding network effectively isolates the donor-acceptor molecules in a two-dimensional layer structure (lamella) leading to the condition where a precise control of the energy and charge transfer is possible.

  20. A cadmium hydroxide complex of a N3S-donor ligand containing two hydrogen bond donors: synthesis, characterization, and CO2 reactivity.

    PubMed

    Allred, Russell A; Huefner, Sara A; Rudzka, Katarzyna; Arif, Atta M; Berreau, Lisa M

    2007-01-21

    Treatment of the ebnpa (N-2-(ethylthio)ethyl-N,N-bis((6-neopentylamino-2-pyridyl)methyl)amine) ligand with a molar equivalent amount of Cd(ClO(4))(2).5H(2)O in CH(3)CN followed by the addition of [Me(4)N]OH.5H(2)O yielded the cadmium hydroxide complex [(ebnpaCd)(2)(mu-OH)(2)](ClO(4))(2) (1). Complex 1 has a binuclear cation in the solid-state with secondary hydrogen-bonding and CH/pi interactions involving the ebnpa ligand. In acetonitrile, 1 forms a binuclear/mononuclear equilibrium mixture. The formation of a mononuclear species has been confirmed by conductance measurements of 1 at low concentrations. Variable temperature studies of the binuclear/mononuclear equilibrium provided the standard enthalpy and entropy associated with the formation of the monomer as DeltaH degrees = +31(2) kJ mol(-1) and DeltaS degrees = +108(8) J mol(-1) K(-1), respectively. Enhanced secondary hydrogen-bonding interactions involving the terminal Cd-OH moiety may help to stabilize the mononuclear complex. Treatment of 1 with CO(2) in acetonitrile results in the formation of a binuclear cadmium carbonate complex, [(ebnpaCd)(2)(mu-CO(3))](ClO(4))(2) (2). PMID:17200755

  1. Comparison of lactate, formate, and propionate as hydrogen donors for the reductive dehalogenation of trichloroethene in a continuous-flow column

    NASA Astrophysics Data System (ADS)

    Azizian, Mohammad F.; Marshall, Ian P. G.; Behrens, Sebastian; Spormann, Alfred M.; Semprini, Lewis

    2010-04-01

    A continuous-flow column study was conducted to analyze the reductive dehalogenation of trichloroethene (TCE) with aquifer material with high content of iron oxides. The column was bioaugmented with the Point Mugu (PM) culture, which is a mixed microbial enrichment culture capable of completely transforming TCE to ethene (ETH). We determined whether lactate, formate, or propionate fermentation resulted in more effective dehalogenation. Reductive dehalogenation, fermentation, and sulfate, Fe(III), and Mn(IV) reduction were all exhibited within the column. Different steady-states of dehalogenation were achieved based on the concentration of substrates added, with effective transformation to ETH obtained when ample electron donor equivalents were provided. Most of the metabolic reducing equivalents were channeled to sulfate, Fe(III), and Mn(IV) reduction. When similar electron reducing equivalents were added, the most effective dehalogenation was achieved with formate, with 14% of the electron equivalents going towards dehalogenation reactions, compared to 6.5% for lactate and 9.6% for propionate. Effective dehalogenation was maintained over 1000 days of column operation. Over 90% of electron equivalents added could be accounted for by the different electron accepting processes in the column, with 50% associated with soluble and precipitated Fe(II) and Mn(II). Bulk Fe(III) and Mn(IV) reduction was rather associated with lactate and propionate addition than formate addition. Sulfate reduction was a competing electron acceptor reaction with all three electron donors. DNA was extracted from solid coupon samples obtained during the course of the experiment and analyzed using 16S rRNA gene clone libraries and quantitative PCR. Lactate and propionate addition resulted in a significant increase in Geobacter, Spirochaetes, and Desulfitobacterium phylotypes relative to " Dehalococcoides" when compared to formate addition. Results from the molecular biological analyses support

  2. Expression of human myoglobin in H9c2 cells enhances toxicity to added hydrogen peroxide

    SciTech Connect

    Witting, Paul K. . E-mail: pwitting@anzac.edu.au; Liao Wenqiang; Harris, Matthew J.; Neuzil, Jiri

    2006-09-22

    Hydrogen peroxide (H{sub 2}O{sub 2}) is implicated in cardiac myocyte (CM) damage during myocardial ischemia-reperfusion (IR) injury. Myoglobin (Mb) is present in CM at significant concentrations and reacts with H{sub 2}O{sub 2} to yield one- and two-electron oxidants that may promote myocardial injury. Paradoxically, hearts from mice lacking Mb are more susceptible to H{sub 2}O{sub 2}-induced dysfunction than the corresponding controls [U. Flogel, A. Godecke, L.O. Klotz, J. Schrader, Role of myoglobin in the anti-oxidant defense of the heart, FASEB J. 18 (2004) 1156-1158]. We have overexpressed wild-type or Y103F variant of human Mb in cultured CMs to test whether Mb protects against H{sub 2}O{sub 2} insult. Contrary to expectation, cells expressing WT or the Y103F Mb show increased mitochondrial dysfunction and apoptosis, and decreased ATP in response to H{sub 2}O{sub 2} that follows the order native < Y103F Mb < WT human Mb consistent with the increasing pro-oxidant activity for these proteins. These data indicate that (i) Mb promotes oxidative damage to cultured CM and (ii) Mb may be a useful target for the design of inhibitors of myocardial IR injury.

  3. Expression of human myoglobin in H9c2 cells enhances toxicity to added hydrogen peroxide.

    PubMed

    Witting, Paul K; Liao, Wen-Qiang; Matthew J Harris; Neuzil, Jiri

    2006-09-22

    Hydrogen peroxide (H2O2) is implicated in cardiac myocyte (CM) damage during myocardial ischemia-reperfusion (IR) injury. Myoglobin (Mb) is present in CM at significant concentrations and reacts with H2O2 to yield one- and two-electron oxidants that may promote myocardial injury. Paradoxically, hearts from mice lacking Mb are more susceptible to H2O2-induced dysfunction than the corresponding controls [U. Flogel, A. Godecke, L.O. Klotz, J. Schrader, Role of myoglobin in the anti-oxidant defense of the heart, FASEB J. 18 (2004) 1156-1158]. We have overexpressed wild-type or Y103F variant of human Mb in cultured CMs to test whether Mb protects against H2O2 insult. Contrary to expectation, cells expressing WT or the Y103F Mb show increased mitochondrial dysfunction and apoptosis, and decreased ATP in response to H2O2 that follows the order native < Y103F Mb < WT human Mb consistent with the increasing pro-oxidant activity for these proteins. These data indicate that (i) Mb promotes oxidative damage to cultured CM and (ii) Mb may be a useful target for the design of inhibitors of myocardial IR injury. PMID:16887098

  4. Added-value from a multi-criteria selection of donor catchments in the prediction of continuous streamflow series at ungauged pollution control-sites

    NASA Astrophysics Data System (ADS)

    Drogue, Gilles; Ben Khediri, Wiem; Conan, Céline

    2016-05-01

    We explore the potential of a multi-criteria selection of donor catchments in the prediction of continuous streamflow series by the spatial proximity method. Three criteria have been used: (1) spatial proximity; (2) physical similarity; (3) stream gauging network topology. An extensive assessment of our spatial proximity method variant is made on a 149 catchment-data set located in the Rhine-Meuse catchment. The competitiveness of the method is evaluated against spatial interpolation of catchment model parameters with ordinary kriging. We found that the spatial proximity approach is more efficient than ordinary kriging. When distance to upstream/downstream stream gauge stations is considered as a second order criterion in the selection of donor catchments, an unprecedented level of efficiency is reached for nested catchments. Nevertheless, the spatial proximity method does not take advantage from physical similarity between donor catchments and receiver catchments because catchments that are the most hydrologically similar to each catchment poorly match with the catchments that are the most physically similar to each catchment.

  5. B4H4 and B4(CH3)4 as Unique Electron Donors in Hydrogen-Bonded and Halogen-Bonded Complexes.

    PubMed

    Del Bene, Janet E; Alkorta, Ibon; Elguero, José

    2016-07-21

    Ab initio MP2/aug'-cc-pVTZ calculations have been carried out on B4H4 and B4(CH3)4 to investigate the base properties of these molecules with Td symmetry. Each face of the tetrahedral structure of B4H4 and B4(CH3)4 is stabilized by a two-electron, three-center B-B-B bond. The face uses these two electrons to act uniquely as an electron-pair donor for the formation of stable hydrogen-bonded and halogen-bonded complexes with C3v symmetry. The hydrogen-bonded complexes are B4H4:HY and B4(CH3)4:HY, with HY = HNC, HF, HCl, HCN, and HCCH; the halogen-bonded complexes are B4H4:ClY and B4(CH3)4:ClY, with ClY = ClF, ClCl, ClNC, ClCN, ClCCH, and ClH. The absolute values of the binding energies of the hydrogen-bonded complexes B4(CH3)4:HY and of the halogen-bonded complexes B4(CH3)4:ClY are significantly greater than the binding energies of the corresponding complexes with B4H4. The binding energies of each series correlate with the distance from the hydrogen-bonded H atom or halogen-bonded Cl atom to the centroid of the interacting face. Charge transfer stabilizes all complexes and occurs from the B2-B3-B4 orbital of the face to the antibonding H-X orbital of HY in hydrogen-bonded complexes and to the antibonding Cl-X orbital of ClY in halogen-bonded complexes, with X being the atom of Y that is directly bonded to either H or Cl. For fixed HY, EOM-CCSD spin-spin coupling constants J(X-B1) are greater than J(X-Bn) for complexes B4H4:HY, even though the X-B1 distances are longer. B1 and Bn are the atoms at the apex and in the interacting face, respectively. Similarly, for complexes B4H4:ClY, J(Cl-B1) is greater than J(Cl-Bn). In the halogen-bonded complexes, both coupling constants correlate with the corresponding distances. PMID:27399838

  6. Dependence on membrane components of methanogenesis from methyl-CoM with formaldehyde or molecular hydrogen as electron donors.

    PubMed

    Deppenmeier, U; Blaut, M; Gottschalk, G

    1989-12-01

    Methane formation from 2-(methylthio)-ethanesulfonate (methyl-CoM) and H2 by the soluble fraction from the methanogenic bacterium strain Gö1 was stimulated up to tenfold by the addition of the membrane fraction. This stimulation was observed with membranes from various methanogenic species belonging to different phylogenetic families, but not with membranes from Escherichia coli or Acetobacterium woodii. Treatment of the membranes with strong oxidants, i.e. O2 and K3[Fe(CN)6], or with SH reagents, i.e. Ag+, p-chloromercuribenzoate or iodoacetamide, caused an irreversible decrease or loss in stimulatory activity, as did heat treatment at temperatures above 78 degrees C. Methanogenesis from methyl-CoM with formaldehyde instead of H2 as electron donor depended similarly on the membrane fraction. With membranes, 1 mol HCHO was oxidized to 1 mol CO2 and allowed the formation of 2 mol CH4 from 2 mol CH3-CoM. Without membranes, per mol of HCHO oxidized 1 mol H2 was formed and 1 mol CH4 was produced from CH3-CoM; the rate was 10-20% of that in the presence of membranes. When methyl-CoM was replaced by an artificial electron acceptor system consisting of methylviologen and metronidazole, the formaldehyde-oxidizing activity was no longer stimulated by the membrane fraction. These results demonstrate for the first time an essential function of membrane components in methanogenic electron transfer. PMID:2513188

  7. Denitrification by Pseudomonas stutzeri coupled with CO2 reduction by Sporomusa ovata with hydrogen as an electron donor assisted by solid-phase humin.

    PubMed

    Xiao, Zhixing; Awata, Takanori; Zhang, Dongdong; Katayama, Arata

    2016-09-01

    A co-culture system comprising an acetogenic bacterium, Sporomusa ovata DSMZ2662, and a denitrifying bacterium, Pseudomonas stutzeri JCM20778, enabled denitrification using H2 as the sole external electron donor and CO2 as the sole external carbon source. Acetate produced by S. ovata supported the heterotrophic denitrification of P. stutzeri. A nitrogen balance study showed the reduction of nitrate to nitrogen gas without the accumulation of nitrite and nitrous oxide in the co-culture system. S. ovata did not show nitrate reduction to ammonium in the co-culture system. Significant proportions of the consumed H2 were utilized for denitrification: 79.9 ± 4.6% in the co-culture system containing solid-phase humin and 62.9±11.1% in the humin-free co-culture system. The higher utilization efficiency of hydrogen in the humin-containing system was attributed to the higher denitrification activity of P. stutzeri under the acetate deficient conditions. The nitrogen removal rate of the humin-containing co-culture system reached 0.19 kg NO3(-)-N·m(-3)·d(-1). Stable denitrification activity for 61 days of successive sub-culturing suggested the robustness of this co-culture system. This study provides a novel strategy for the in situ enhancement of microbial denitrification. PMID:26975755

  8. The Effects of Added Hydrogen on Noble Gas Discharges Used as Ambient Desorption/Ionization Sources for Mass Spectrometry.

    PubMed

    Ellis, Wade C; Lewis, Charlotte R; Openshaw, Anna P; Farnsworth, Paul B

    2016-09-01

    We demonstrate the effectiveness of using hydrogen-doped argon as the support gas for the dielectric barrier discharge (DBD) ambient desorption/ionization (ADI) source in mass spectrometry. Also, we explore the chemistry responsible for the signal enhancement observed when using both hydrogen-doped argon and hydrogen-doped helium. The hydrogen-doped argon was tested for five analytes representing different classes of molecules. Addition of hydrogen to the argon plasma gas enhanced signals for gas-phase analytes and for analytes coated onto glass slides in positive and negative ion mode. The enhancements ranged from factors of 4 to 5 for gas-phase analytes and factors of 2 to 40 for coated slides. There was no significant increase in the background. The limit of detection for caffeine was lowered by a factor of 79 using H2/Ar and 2 using H2/He. Results are shown that help explain the fundamental differences between the pure-gas discharges and those that are hydrogen-doped for both argon and helium. Experiments with different discharge geometries and grounding schemes indicate that observed signal enhancements are strongly dependent on discharge configuration. Graphical Abstract ᅟ. PMID:27380389

  9. The Effects of Added Hydrogen on Noble Gas Discharges Used as Ambient Desorption/Ionization Sources for Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Ellis, Wade C.; Lewis, Charlotte R.; Openshaw, Anna P.; Farnsworth, Paul B.

    2016-09-01

    We demonstrate the effectiveness of using hydrogen-doped argon as the support gas for the dielectric barrier discharge (DBD) ambient desorption/ionization (ADI) source in mass spectrometry. Also, we explore the chemistry responsible for the signal enhancement observed when using both hydrogen-doped argon and hydrogen-doped helium. The hydrogen-doped argon was tested for five analytes representing different classes of molecules. Addition of hydrogen to the argon plasma gas enhanced signals for gas-phase analytes and for analytes coated onto glass slides in positive and negative ion mode. The enhancements ranged from factors of 4 to 5 for gas-phase analytes and factors of 2 to 40 for coated slides. There was no significant increase in the background. The limit of detection for caffeine was lowered by a factor of 79 using H2/Ar and 2 using H2/He. Results are shown that help explain the fundamental differences between the pure-gas discharges and those that are hydrogen-doped for both argon and helium. Experiments with different discharge geometries and grounding schemes indicate that observed signal enhancements are strongly dependent on discharge configuration.

  10. The Effects of Added Hydrogen on Noble Gas Discharges Used as Ambient Desorption/Ionization Sources for Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Ellis, Wade C.; Lewis, Charlotte R.; Openshaw, Anna P.; Farnsworth, Paul B.

    2016-07-01

    We demonstrate the effectiveness of using hydrogen-doped argon as the support gas for the dielectric barrier discharge (DBD) ambient desorption/ionization (ADI) source in mass spectrometry. Also, we explore the chemistry responsible for the signal enhancement observed when using both hydrogen-doped argon and hydrogen-doped helium. The hydrogen-doped argon was tested for five analytes representing different classes of molecules. Addition of hydrogen to the argon plasma gas enhanced signals for gas-phase analytes and for analytes coated onto glass slides in positive and negative ion mode. The enhancements ranged from factors of 4 to 5 for gas-phase analytes and factors of 2 to 40 for coated slides. There was no significant increase in the background. The limit of detection for caffeine was lowered by a factor of 79 using H2/Ar and 2 using H2/He. Results are shown that help explain the fundamental differences between the pure-gas discharges and those that are hydrogen-doped for both argon and helium. Experiments with different discharge geometries and grounding schemes indicate that observed signal enhancements are strongly dependent on discharge configuration.

  11. An exogenous hydrogen sulphide donor, NaHS, inhibits the apoptosis signaling pathway to exert cardio-protective effects in a rat hemorrhagic shock model

    PubMed Central

    Xu, Yanjie; Dai, Xiongwei; Zhu, Danxia; Xu, Xiaoli; Gao, Cao; Wu, Changping

    2015-01-01

    Hydrogen sulfide (H2S) has been reported to be interwined in multiple systems, specifically in the cardiovascular system. However, the mechanisms underlying remain controversial. In the present study, we assessed the cardio-protective effects of H2S in the rat hemorrhagic shock model. Hemorrhagic shock was induced in adult male Sprague-Dawley rats by drawing blood from the femoral artery to maintain the mean arterial pressure at 35-40 mmHg for 1.5 h. The rats were assigned to four groups and the H2S donor, NaHS (28 μmol/kg, i.p.), was injected before the resuscitation in certain groups. After resuscitation the animals were observed and then killed to harvest the hearts. The morphological investigation and ultrastructural analyses were done and apoptotic cells were detected. The levels of relevant proteins were examined using Western blotting and immunohistochemical analyses. Resuscitated hemorrhagic shock induced heart injury and significantly increased the levels of serum myocardial enzymes, creatine kinase (CK) and lactate dehydrogenase (LDH) levels. Furthermore, it caused marked increase of apoptotic cells in heart tissue. Moreover, the expression of death receptor Fas and Fas-ligand, as well as the expression of apoptosis-relevant proteins active-caspase 3 and active-caspase 8 were markedly increased. Administration of NaHS significantly ameliorated hemorrhagic shock caused hemodynamic deterioration, decreased myocardial enzymes elevation, protected myocardial ultrastructure, and inhibited the expression of apoptosis-relevant proteins. It suggested that H2S might exert its cardio-protective roles via both the extrinsic Fas/FasL/caspase-8/caspase-3 pathway and the intrinsic mitochondria-involved pathways. PMID:26261501

  12. Binding energy of the ground and first few excited states of hydrogenic donor impurity in a rectangular GaAs quantum dot in the presence of electric field

    NASA Astrophysics Data System (ADS)

    Wang, Sheng; Kang, Yun; Li, Xian-Li

    2014-12-01

    Within the quasi-one-dimensional effective potential model and effective mass approximation, we calculate the ground and the first 9 excited-state binding energies of a hydrogenic donor impurity in a rectangular quantum dot (RQD) in the presence of electric field. The analytical form of the quasi-one-dimensional effective potential replacing the three-dimensional Coulomb potential in our model is derived by Fourier transforms. We discuss detailedly dependence of the binding energies on the impurity positions and electric fields. For the ground-state binding energy, our results qualitatively agree with that of Mendoza et al. (2005) in which they only calculated the ground-state binding energies in cubic quantum dots by variational method. However, for first 9 excited-state binding energies, such dependence has complex manner since there are two or three peaks in the electronic probability density distribution curves. The strengths and positions of these peaks in RQD affect the interaction potential between electron and impurity, which appears to be the critical control on the binding energies of impurity. The applied electric field pushes the positions of these peaks downwards, and the strengths of peaks located at the upper half of RQD increase while the strengths of lower peaks firstly decrease, then increase with increasing electric field. The high peak strength can lead to increase of the binding energy while the large distance between the position of peak and impurity center results in reduce of the energy, which is an interesting competition. This competition is more obvious for excited-state binding energies of off-central impurity.

  13. Hyperfine and Nuclear Quadrupole Tensors of Nitrogen Donors in the QA Site of Bacterial Reaction Centers: Correlation of the Histidine Nδ Tensors with Hydrogen Bond Strength

    PubMed Central

    2015-01-01

    X- and Q-band pulsed EPR spectroscopy was applied to study the interaction of the QA site semiquinone (SQA) with nitrogens from the local protein environment in natural abundance 14N and in 15N uniformly labeled photosynthetic reaction centers of Rhodobacter sphaeroides. The hyperfine and nuclear quadrupole tensors for His-M219 Nδ and Ala-M260 peptide nitrogen (Np) were estimated through simultaneous simulation of the Q-band 15N Davies ENDOR, X- and Q-band 14,15N HYSCORE, and X-band 14N three-pulse ESEEM spectra, with support from DFT calculations. The hyperfine coupling constants were found to be a(14N) = 2.3 MHz, T = 0.3 MHz for His-M219 Nδ and a(14N) = 2.6 MHz, T = 0.3 MHz for Ala-M260 Np. Despite that His-M219 Nδ is established as the stronger of the two H-bond donors, Ala-M260 Np is found to have the larger value of a(14N). The nuclear quadrupole coupling constants were estimated as e2Qq/4h = 0.38 MHz, η = 0.97 and e2Qq/4h = 0.74 MHz, η = 0.59 for His-M219 Nδ and Ala-M260 Np, respectively. An analysis of the available data on nuclear quadrupole tensors for imidazole nitrogens found in semiquinone-binding proteins and copper complexes reveals these systems share similar electron occupancies of the protonated nitrogen orbitals. By applying the Townes–Dailey model, developed previously for copper complexes, to the semiquinones, we find the asymmetry parameter η to be a sensitive probe of the histidine Nδ–semiquinone hydrogen bond strength. This is supported by a strong correlation observed between η and the isotropic coupling constant a(14N) and is consistent with previous computational works and our own semiquinone-histidine model calculations. The empirical relationship presented here for a(14N) and η will provide an important structural characterization tool in future studies of semiquinone-binding proteins. PMID:25026433

  14. Pharmacological actions of the slow release hydrogen sulfide donor GYY4137 on phenylephrine-induced tone in isolated bovine ciliary artery.

    PubMed

    Chitnis, Madhura Kulkarni; Njie-Mbye, Ya Fatou; Opere, Catherine A; Wood, Mark E; Whiteman, Matthew; Ohia, Sunny E

    2013-11-01

    Hydrogen sulfide (H2S), a colorless gas characterized by its pungent odor of rotten eggs has been reported to elicit relaxation effects on basal and pre-contracted non-ocular smooth muscles of several mammalian species. In the present study, we investigated the pharmacological actions of a H2S donor, GYY4137 on isolated bovine posterior ciliary artery after contraction with the adrenergic receptor agonist, phenylephrine. Furthermore, we studied the underlying mechanism of inhibitory action of GYY4137 on the posterior ciliary arteries. Isolated bovine posterior ciliary arteries were mounted in oxygenated organ baths and changes in isometric tension were measured with a Grass FT03 transducer connected to a recorder using a Grass Polyview Software. The relaxant actions of GYY4137 on phenylephrine pre-contracted arteries were observed in the absence and presence of an inhibitor of cyclo-oxygenase, flurbiprofen. Furthermore, the inhibitory effects of GYY4137 were studied in the absence or presence of inhibitors/activators of biosynthetic enzymes for H2S and nitric oxide production, as well as specific ion channel blockers. In the concentration range, 100 nM to 100 μM, GYY4137 elicited a concentration-dependant relaxation of phenylephrine-induced tone in isolated posterior ciliary arteries, with IC50 value of 13.4 ± 1.9 μM (n = 6). The cyclo-oxygenase inhibitor, flurbiprofen, significantly (p < 0.01) enhanced the relaxation induced by GYY4137 yielding IC50 value of 0.13 ± 0.08 μM (n = 6). Both the inhibitors of cystathionine β-synthase (aminooxyacetic acid, AOAA, 30 μM) and cystathionine γ-lyase (propargylglycine, PAG, 1 mM) caused significant (p < 0.05) rightward shifts in the concentration-response curve to GYY4137. Furthermore, the KATP channel antagonist, glibenclamide (100 μM) significantly (p < 0.01) attenuated the relaxant action induced by GYY4137 on bovine ciliary artery. Conversely, the activator of cystathionine β-synthase, SAM (100 μM) and an

  15. Mechanochemical hydrogenation of coal

    DOEpatents

    Yang, Ralph T.; Smol, Robert; Farber, Gerald; Naphtali, Leonard M.

    1981-01-01

    Hydrogenation of coal is improved through the use of a mechanical force to reduce the size of the particulate coal simultaneously with the introduction of gaseous hydrogen, or other hydrogen donor composition. Such hydrogen in the presence of elemental tin during this one-step size reduction-hydrogenation further improves the yield of the liquid hydrocarbon product.

  16. Removal of carbon monoxide from hydrogen-rich fuels by selective low-temperature oxidation over base metal added platinum catalysts

    NASA Astrophysics Data System (ADS)

    Suh, Dong Jin; Kwak, Chan; Kim, Jin-Hong; Kwon, Se Mann; Park, Tae-Jin

    Various catalysts containing different catalytic materials, supports, and additives were tested for the preferential oxidation (PROX) of carbon monoxide from a hydrogen-rich gas stream. The results were analyzed based on three reactions involved in the PROX: oxidation of carbon monoxide, H 2-O 2 reaction, and methanation. The PROX reactions were performed in two reaction systems, one for catalyst screening and kinetic study and the other for simulation of the catalytic performance under real reaction conditions. The performances of PROX on different catalysts, varying active components, supports, and additives, were ranked in terms of carbon monoxide conversion and hydrogen consumption. Base metal added platinum catalysts exhibited excellent ability for the carbon monoxide removal. TPR results indicated that a new active species was formed resulting in the enhancement of catalytic activity. PtCo/Al 2O 3 was tested with a simulated steam-reformed fuel for confirmation of its high activity. The effect of operating conditions was analyzed on the PtCo/Al 2O 3, and the optimum conditions for PROX were obtained.

  17. AP39, a Mitochondria-Targeted Hydrogen Sulfide Donor, Supports Cellular Bioenergetics and Protects against Alzheimer's Disease by Preserving Mitochondrial Function in APP/PS1 Mice and Neurons.

    PubMed

    Zhao, Feng-Li; Fang, Fang; Qiao, Pei-feng; Yan, Ning; Gao, Dan; Yan, Yong

    2016-01-01

    Increasing evidence suggests that mitochondrial functions are altered in AD and play an important role in AD pathogenesis. It has been established that H2S homeostasis is balanced in AD. The emerging mitochondrial roles of H2S include antioxidation, antiapoptosis, and the modulation of cellular bioenergetics. Here, using primary neurons from the well-characterized APP/PS1 transgenic mouse model, we studied the effects of AP39 (a newly synthesized mitochondrially targeted H2S donor) on mitochondrial function. AP39 increased intracellular H2S levels, mainly in mitochondrial regions. AP39 exerted dose-dependent effects on mitochondrial activity in APP/PS1 neurons, including increased cellular bioenergy metabolism and cell viability at low concentrations (25-100 nM) and decreased energy production and cell viability at a high concentration (250 nM). Furthermore, AP39 (100 nM) increased ATP levels, protected mitochondrial DNA, and decreased ROS generation. AP39 regulated mitochondrial dynamics, shifting from fission toward fusion. After 6 weeks, AP39 administration to APP/PS1 mice significantly ameliorated their spatial memory deficits in the Morris water maze and NORT and reduced Aβ deposition in their brains. Additionally, AP39 inhibited brain atrophy in APP/PS1 mice. Based on these results, AP39 was proposed as a promising drug candidate for AD treatment, and its anti-AD mechanism may involve protection against mitochondrial damage. PMID:27057285

  18. AP39, a Mitochondria-Targeted Hydrogen Sulfide Donor, Supports Cellular Bioenergetics and Protects against Alzheimer's Disease by Preserving Mitochondrial Function in APP/PS1 Mice and Neurons

    PubMed Central

    Zhao, Feng-li; Fang, Fang; Qiao, Pei-feng; Yan, Ning; Gao, Dan; Yan, Yong

    2016-01-01

    Increasing evidence suggests that mitochondrial functions are altered in AD and play an important role in AD pathogenesis. It has been established that H2S homeostasis is balanced in AD. The emerging mitochondrial roles of H2S include antioxidation, antiapoptosis, and the modulation of cellular bioenergetics. Here, using primary neurons from the well-characterized APP/PS1 transgenic mouse model, we studied the effects of AP39 (a newly synthesized mitochondrially targeted H2S donor) on mitochondrial function. AP39 increased intracellular H2S levels, mainly in mitochondrial regions. AP39 exerted dose-dependent effects on mitochondrial activity in APP/PS1 neurons, including increased cellular bioenergy metabolism and cell viability at low concentrations (25–100 nM) and decreased energy production and cell viability at a high concentration (250 nM). Furthermore, AP39 (100 nM) increased ATP levels, protected mitochondrial DNA, and decreased ROS generation. AP39 regulated mitochondrial dynamics, shifting from fission toward fusion. After 6 weeks, AP39 administration to APP/PS1 mice significantly ameliorated their spatial memory deficits in the Morris water maze and NORT and reduced Aβ deposition in their brains. Additionally, AP39 inhibited brain atrophy in APP/PS1 mice. Based on these results, AP39 was proposed as a promising drug candidate for AD treatment, and its anti-AD mechanism may involve protection against mitochondrial damage. PMID:27057285

  19. Tuning the tetrahedrality of the hydrogen-bonded network of water: Comparison of the effects of pressure and added salts

    NASA Astrophysics Data System (ADS)

    Prasad, Saurav; Chakravarty, Charusita

    2016-06-01

    Experiments and simulations demonstrate some intriguing equivalences in the effect of pressure and electrolytes on the hydrogen-bonded network of water. Here, we examine the extent and nature of equivalence effects between pressure and salt concentration using relationships between structure, entropy, and transport properties based on two key ideas: first, the approximation of the excess entropy of the fluid by the contribution due to the atom-atom pair correlation functions and second, Rosenfeld-type excess entropy scaling relations for transport properties. We perform molecular dynamics simulations of LiCl-H2O and bulk SPC/E water spanning the concentration range 0.025-0.300 molefraction of LiCl at 1 atm and pressure range from 0 to 7 GPa, respectively. The temperature range considered was from 225 to 350 K for both the systems. To establish that the time-temperature-transformation behaviour of electrolyte solutions and water is equivalent, we use the additional observation based on our simulations that the pair entropy behaves as a near-linear function of pressure in bulk water and of composition in LiCl-H2O. This allows for the alignment of pair entropy isotherms and allows for a simple mapping of pressure onto composition. Rosenfeld-scaling implies that pair entropy is semiquantitatively related to the transport properties. At a given temperature, equivalent state points in bulk H2O and LiCl-H2O (at 1 atm) are defined as those for which the pair entropy, diffusivity, and viscosity are nearly identical. The microscopic basis for this equivalence lies in the ability of both pressure and ions to convert the liquid phase into a pair-dominated fluid, as demonstrated by the O-O-O angular distribution within the first coordination shell of a water molecule. There are, however, sharp differences in local order and mechanisms for the breakdown of tetrahedral order by pressure and electrolytes. Increasing pressure increases orientational disorder within the first

  20. Tuning the tetrahedrality of the hydrogen-bonded network of water: Comparison of the effects of pressure and added salts.

    PubMed

    Prasad, Saurav; Chakravarty, Charusita

    2016-06-21

    Experiments and simulations demonstrate some intriguing equivalences in the effect of pressure and electrolytes on the hydrogen-bonded network of water. Here, we examine the extent and nature of equivalence effects between pressure and salt concentration using relationships between structure, entropy, and transport properties based on two key ideas: first, the approximation of the excess entropy of the fluid by the contribution due to the atom-atom pair correlation functions and second, Rosenfeld-type excess entropy scaling relations for transport properties. We perform molecular dynamics simulations of LiCl-H2O and bulk SPC/E water spanning the concentration range 0.025-0.300 molefraction of LiCl at 1 atm and pressure range from 0 to 7 GPa, respectively. The temperature range considered was from 225 to 350 K for both the systems. To establish that the time-temperature-transformation behaviour of electrolyte solutions and water is equivalent, we use the additional observation based on our simulations that the pair entropy behaves as a near-linear function of pressure in bulk water and of composition in LiCl-H2O. This allows for the alignment of pair entropy isotherms and allows for a simple mapping of pressure onto composition. Rosenfeld-scaling implies that pair entropy is semiquantitatively related to the transport properties. At a given temperature, equivalent state points in bulk H2O and LiCl-H2O (at 1 atm) are defined as those for which the pair entropy, diffusivity, and viscosity are nearly identical. The microscopic basis for this equivalence lies in the ability of both pressure and ions to convert the liquid phase into a pair-dominated fluid, as demonstrated by the O-O-O angular distribution within the first coordination shell of a water molecule. There are, however, sharp differences in local order and mechanisms for the breakdown of tetrahedral order by pressure and electrolytes. Increasing pressure increases orientational disorder within the first

  1. Solution chemistry of a water-soluble eta2-H2 ruthenium complex: evidence for coordinated H2 acting as a hydrogen bond donor.

    PubMed

    Szymczak, Nathaniel K; Zakharov, Lev N; Tyler, David R

    2006-12-13

    The ability of an eta2-H2 ligand to participate in intermolecular hydrogen bonding in solution has long been an unresolved issue. Such species are proposed to be key intermediates in numerous important reactions such as the proton-transfer pathway of H2 production by hydrogenase enzymes. We present the synthesis of several new water-soluble ruthenium coordination complexes including an eta2-H2 complex that is surprisingly inert to substitution by water. The existence of dihydrogen hydrogen bonding (DHHB) was experimentally probed by monitoring the chemical shift of H-bonded Ru-(H2) complexes using NMR spectroscopy, by UV-visible spectroscopy, and by monitoring the rotational dynamics of a hydrogen-bonding probe molecule. The results provide strong evidence that coordinated H2 can indeed participate in intermolecular hydrogen bonding to bulk solvent and other H-bond acceptors. PMID:17147394

  2. Introducing a Hydrogen-Bond Donor into a Weakly Nucleophilic Brønsted Base: Alkali Metal Hexamethyldisilazides (MHMDS, M=Li, Na, K, Rb and Cs) with Ammonia.

    PubMed

    Neufeld, Roman; Michel, Reent; Herbst-Irmer, Regine; Schöne, Ralf; Stalke, Dietmar

    2016-08-22

    Alkali metal 1,1,1,3,3,3-hexamethyldisilazide (MHMDSs) are one of the most utilised weakly nucleophilic Brønsted bases in synthetic chemistry and especially in natural product synthesis. Like lithium organics, they aggregate depending on the employed donor solvents. Thus, they show different reactivity and selectivity as a function of their aggregation and solvation state. To date, monomeric LiHMDS with monodentate donor bases was only characterised in solution. Since the first preparation of LiHMDS in 1959 by Wannagat and Niederprüm, all efforts to crystallise monomeric LiHMDS in the absence of chelating ligands failed. Herein, we present ammonia adducts of LiHMDS, NaHMDS, KHMDS, RbHMDS and CsHMDS with unprecedented aggregation motifs: 1) The hitherto missing monomeric key compound in the LiHMDS aggregation architectures. Monomeric crystal structures of trisolvated LiHMDS (1) and NaHMDS (2), showing unique intermolecular hydrogen bonds, 2) the unprecedented tetrasolvated KHMDS (3) and RbHMDS (4) dimers and 3) the disolvated CsHMDS (5) dimer with very close intermolecular Si-CH3 ⋅⋅⋅Cs s-block "agostic" interactions have been prepared and characterised by single-crystal X-ray structure analysis. PMID:27457218

  3. QALE analysis of CO dissociative kinetics of Ru(CO)4L (L = P-donor ligands): accelerating effects of hydrogen in PHnR(3 - n) ligands (n = 1-2).

    PubMed

    Babij, Claudia; Chen, Lezhan; Koshevoy, Igor O; Poë, Anthony J

    2004-03-01

    Studies of CO-dissociative substitution reactions of the complexes Ru(CO)4L (L = a wide variety of P-donor ligands) have been extended and analysis of the results by the QALE methodology has been refined (QALE = quantitative analysis of ligand effects). Rates increase substantially with increasing size of L, mainly as a consequence of increasingly favourable activation entropies. These can be associated with increasing Ru-CO bond breaking that is compensated enthalpically by increasing Ru-P bond making allowed by release of steric strain. Explicit allowance for pi-acidity shows that these effects are just significant while sigma-donor and aryl effects are negligible. However, pendent hydrogen atoms, attached directly to the phosphorus atoms, have a pronounced and unique positive effect on the rates, with significant kinetic isotope effects (KIE). This is associated with the novel occurrence of direct Ru-H or incipient Ru-(eta2-P-H) agostic bond making as the CO ligand departs. PMID:15252507

  4. New organic donor-acceptor-π-acceptor sensitizers for efficient dye-sensitized solar cells and photocatalytic hydrogen evolution under visible-light irradiation.

    PubMed

    Li, Xing; Cui, Shicong; Wang, Dan; Zhou, Ying; Zhou, Hao; Hu, Yue; Liu, Jin-Gang; Long, Yitao; Wu, Wenjun; Hua, Jianli; Tian, He

    2014-10-01

    Two organic donor-acceptor-π-acceptor (D-A-π-A) sensitizers (AQ and AP), containing quinoxaline/pyrido[3,4-b]pyrazine as the auxiliary acceptor, have been. Through fine-tuning of the auxiliary acceptor, a higher designed and synthesized photoelectric conversion efficiency of 6.02% for the AQ-based dye-sensitized solar cells under standard global AM1.5 solar conditions was achieved. Also, it was found that AQ-Pt/TiO2 photocatalysts displayed a better rate of H2 evolution under visible-light irradiation (420 nm<λ<780 nm) because of the stability of the oxidized states and the lower rates of electron recombination. Importantly, sensitizers AQ and AP-Pt/TiO2 showed strong photocatalytic activity during continuous light soaking for 10 h with methanol as the sacrificial electron donor. Additionally, the processes of their intermolecular electron transfer were further investigated theoretically by using time-dependent DFT. The calculated results indicate that the auxiliary acceptor plays the role of an electron trap and results in broad spectral responses. PMID:25154958

  5. Modeling the syn disposition of nitrogen donors in non-heme diiron enzymes. Synthesis, characterization, and hydrogen peroxide reactivity of diiron(III) complexes with the syn N-donor ligand H2BPG2DEV.

    PubMed

    Friedle, Simone; Kodanko, Jeremy J; Morys, Anna J; Hayashi, Takahiro; Moënne-Loccoz, Pierre; Lippard, Stephen J

    2009-10-14

    contrast to hydrogen peroxide reactions of diiron(III) complexes that lack a dinucleating ligand, the intermediates generated here could be re-formed in significant quantities after a second addition of H(2)O(2), as observed spectroscopically and by mass spectrometry. PMID:19757795

  6. Thermodynamics of the hydrogen bonding of nitrogen-containing cyclic and aromatic compounds with proton donors: The structure-property relationship

    NASA Astrophysics Data System (ADS)

    Rakipov, I. T.; Varfolomeev, M. A.; Kirgizov, A. Yu.; Solomonov, B. N.

    2014-12-01

    Enthalpies of dissolution are measured at infinite dilution of nitrogen-containing cyclic (pyrrolidine, piperidine) and aromatic compounds (aniline, N-methylaniline, N,N-dimethylaniline, N-methylimidazole, pyridine, 2-, 3-, 4-methylpyridine, pyrrole, N-methylpyrrole) in chloroform and dichloromethane, and vice versa ( T = 298.15 K). The enthalpies of hydrogen bonds in the above systems are calculated. Relationships between resulting thermochemical data and the structure of nitrogen-containing cyclic and aromatic compounds are explored.

  7. Solicited kidney donors: Are they coerced?

    PubMed

    Serur, David; Bretzlaff, Gretchen; Christos, Paul; Desrosiers, Farrah; Charlton, Marian

    2015-12-01

    Most non-directed donors (NDDs) decide to donate on their own and contact the transplant centre directly. Some NDDs decide to donate in response to community solicitation such as newspaper ads or donor drives. We wished to explore whether subtle coercion might be occurring in such NDDs who are part of a larger community. One successful organization in a community in Brooklyn, NY, provides about 50 NDDs per year for recipients within that community. The donors answer ads in local papers and attend donor drives. Herein, we evaluated the physical and emotional outcomes of community-solicited NDDs in comparison to traditional NDDs who come from varied communities and are not responding to a specific call for donation. An assessment of coercion was used as well. PMID:26511772

  8. Relationship of Hydrogen Bioavailability to Chromate Reduction in Aquifer Sediments

    PubMed Central

    Marsh, Tamara L.; McInerney, Michael J.

    2001-01-01

    Biological Cr(VI) reduction was studied in anaerobic sediments from an aquifer in Norman, Okla. Microcosms containing sediment and mineral medium were amended with various electron donors to determine those most important for biological Cr(VI) reduction. Cr(VI) (about 340 μM) was reduced with endogenous substrates (no donor), or acetate was added. The addition of formate, hydrogen, and glucose stimulated Cr(VI) reduction compared with reduction in unamended controls. From these sediments, an anaerobic Cr(VI)-utilizing enrichment was obtained that was dependent upon hydrogen for both growth and Cr(VI) reduction. No methane was produced by the enrichment, which reduced about 750 μM Cr(VI) in less than six days. The dissolved hydrogen concentration was used as an indicator of the terminal electron accepting process occurring in the sediments. Microcosms with sediments, groundwater, and chromate metabolized hydrogen to a concentration below the detection limits of the mercury vapor gas chromatograph. In microcosms without chromate, the hydrogen concentration was about 8 nM, a concentration comparable to that under methanogenic conditions. When these microcosms were amended with 500 μM Cr(VI), the dissolved hydrogen concentration quickly fell below the detection limits. These results showed that the hydrogen concentration under chromate-reducing conditions became very low, as low as that reported under nitrate- and manganese-reducing conditions, a result consistent with the free energy changes for these reactions. The utilization of formate, lactate, hydrogen, and glucose as electron donors for Cr(VI) reduction indicates that increasing the availability of hydrogen results in a greater capacity for Cr(VI) reduction. This conclusion is supported by the existence of an enrichment dependent upon hydrogen for growth and Cr(VI) reduction. PMID:11282599

  9. The roles of methanogens and acetogens in dechlorination of trichloroethene using different electron donors.

    PubMed

    Wen, Li-Lian; Zhang, Yin; Pan, Ya-Wei; Wu, Wen-Qi; Meng, Shao-Hua; Zhou, Chen; Tang, Youneng; Zheng, Ping; Zhao, He-Ping

    2015-12-01

    We evaluated the effects of methanogens and acetogens on the function and structure of microbial communities doing reductive dechlorination of trichloroethene (TCE) by adding four distinct electron donors: lactate, a fermentable organic; acetate, a non-fermentable organic; methanol, a fermentable 1-C (carbon) organic; and hydrogen gas (H2), the direct electron donor for reductive dechlorination by Dehalococcoides. The fermentable electron donors had faster dechlorination rates, more complete dechlorination, and higher bacterial abundances than the non-fermentable electron donors during short-term tests. Phylotypes of Dehalococcoides were relatively abundant (≥9%) for the cultures fed with fermentable electron donors but accounted for only ~1-2% of the reads for the cultures fed by the non-fermentable electron donors. Routing electrons to methanogenesis and a low ratio of Dehalococcoides/methanogenesis (Dhc/mcrA) were associated with slow and incomplete reductive dechlorination with methanol and H2. When fermentable substrates were applied as electron donors, a Dhc/mcrA ratio ≥6.4 was essential to achieve fast and complete dechlorination of TCE to ethene. When methanogenesis was suppressed using 2-bromoethanesulfonate (BES), achieving complete dechlorination of TCE to ethane required a minimum abundance of the mcrA gene. Methanobacterium appeared to be important for maintaining a high dechlorination rate, probably by providing Dehalococcoides with cofactors other than vitamin B12. Furthermore, the presence of homoacetogens also was important to maintain a high dechlorination rate, because they provided acetate as Dehalococcoides's obligatory carbon source and possibly cofactors. PMID:26233753

  10. Progress in donor assisted coal liquefaction: Hydroaromatic compound formation

    SciTech Connect

    Kottenstette, R.J.; Stephens, H.P.

    1993-12-31

    The role of hydrogen donor compounds in coal liquefaction has been extensively investigated since the mid 1960`s using model compounds and process derived hydrogen donor solvents. Our recent research and that of other investigators have shown that two model compounds in particular have great efficacy in solvating low rank coals. 1,2,3,10b tetrahydrofluoranthene (H{sub 4}Fl) and 1,2,3,6,7,8 hexahydropyrene (H{sub 6}Py) have been used to dissolve Wyodak coal to > 95% soluble material as measured by tetrahydrofuran (THF). Although these hydrogen donors are very effective, they may not be found in any significant concentrations in actual liquefaction process recycle solvents. Therefore, studies with process derived recycle materials are necessary to understand donor solvent chemistry. The objective of this paper is to present results of solvent hydrogenation experiments using heavy distillate solvents produced during testing at the Wilsonville Advanced Coal Liquefaction Test Facility. We evaluated the impact of hydrogenation conditions upon hydrogen donor formation in process derived distillates and compared these process derived solvents with the highly effective H{sub 4}Fl and H{sub 6}Py donors in coal liquefaction tests. This paper presents data on reaction conditions used for distillate hydrotreating and subsequent coal liquefaction, with an aim toward understanding the relationship between reaction conditions and donor solvent quality in recycle distillates.

  11. Program PROTEUS for adding hydrogens to a protein structure and electrostatic field across carotenoids in light harvesting complexes and reaction centers from bacterial sources

    NASA Astrophysics Data System (ADS)

    Lipovaca, Samir

    The hydrogen construction method presented in the program PROTEUS treats hydrogens depending on their torsional degrees of freedom. The positions of hydrogens with restricted torsional degrees of freedom are completely determined by the heavy atoms positions in the structure. The hydroxyl and water hydrogens are the only hydrogens that PROTEUS accepts as movable hydrogens (having rotational degrees of freedom). Their positions are determined by the interactions with neighboring atoms. PROTEUS interaction energy corresponds to a view that the hydrogen bond is affected, besides electrostatic effects and steric constraints of neighboring groups, by an inherent energy barrier that opposes free rotation of the hydroxyl hydrogen. For the water hydrogens that barrier is zero. The hydroxyl and water hydrogens are minimized within a short distance using the Threshold Accepting (TA) energy minimization method. PROTEUS can provide reasonable positions of movable hydrogens and a good initial protein structure for further investigations. We applied the program PROTEUS to place hydrogens in several resolved three-dimensional crystal structures of light harvesting complexes (LHCs) and reaction centers (RCs) from bacterial sources. Using program DelPhi we calculated the local electrostatic field across carotenoid generated by the protein's charges. In each structure we identified amino acids responsible for the field. Much of the field is generated by the charged residues. There are different ways that a RC or LHC uses charged residues. A nearby dipole consisting of the charged residues which are ionized in the physiological pH range (like Arg-Asp), is often used. Clusters of charged residues or scattered isolated charged residues around the carotenoid molecule also contribute. The polarizable field is not necessarily along the carotenoid molecule principal axis. For soluble LHCs the contribution of polar residues to the field cannot be neglected. Our calculations indicate an

  12. Cobalt(III) Werner Complexes with 1,2-Diphenylethylenediamine Ligands: Readily Available, Inexpensive, and Modular Chiral Hydrogen Bond Donor Catalysts for Enantioselective Organic Synthesis

    PubMed Central

    2015-01-01

    In the quest for new catalysts that can deliver single enantiomer pharmaceuticals and agricultural chemicals, chemists have extensively mined the “chiral pool”, with little in the way of inexpensive, readily available building blocks now remaining. It is found that Werner complexes based upon the D3 symmetric chiral trication [Co(en)3]3+ (en = 1,2-ethylenediamine), which features an earth abundant metal and cheap ligand type, and was among the first inorganic compounds resolved into enantiomers 103 years ago, catalyze a valuable carbon–carbon bond forming reaction, the Michael addition of malonate esters to nitroalkenes, in high enantioselectivities and without requiring inert atmosphere conditions. The title catalysts, [Co((S,S)-dpen)3]3+ ((S,S)-33+) 3X–, employ a commercially available chiral ligand, (S,S)-1,2-diphenylethylenediamine. The rates and ee values are functions of the configuration of the cobalt center (Λ/Δ) and the counteranions, which must be lipophilic to solubilize the trication in nonaqueous media. The highest enantioselectivities are obtained with Λ and 2Cl–BArf–, 2BF4–BArf–, or 3BF4– salts (BArf– = B(3,5-C6H3(CF3)2)4–). The substrates are not activated by metal coordination, but rather by second coordination sphere hydrogen bonding involving the ligating NH2 groups. Crystal structures and NMR data indicate enthalpically stronger interactions with the NH moieties related by the C3 symmetry axis, as opposed to those related by the C2 symmetry axes; rate trends and other observations suggest this to be the catalytically active site. Both Λ- and Δ-(S,S)-33+ 2Cl–BArf– are effective catalysts for additions of β-ketoesters to RO2CN=NCO2R species (99–86% yields, 81–76% ee), which provide carbon–nitrogen bonds and valuable precursors to α-amino acids. PMID:27162946

  13. Cobalt(III) Werner Complexes with 1,2-Diphenylethylenediamine Ligands: Readily Available, Inexpensive, and Modular Chiral Hydrogen Bond Donor Catalysts for Enantioselective Organic Synthesis.

    PubMed

    Lewis, Kyle G; Ghosh, Subrata K; Bhuvanesh, Nattamai; Gladysz, John A

    2015-03-25

    In the quest for new catalysts that can deliver single enantiomer pharmaceuticals and agricultural chemicals, chemists have extensively mined the "chiral pool", with little in the way of inexpensive, readily available building blocks now remaining. It is found that Werner complexes based upon the D3 symmetric chiral trication [Co(en)3](3+) (en = 1,2-ethylenediamine), which features an earth abundant metal and cheap ligand type, and was among the first inorganic compounds resolved into enantiomers 103 years ago, catalyze a valuable carbon-carbon bond forming reaction, the Michael addition of malonate esters to nitroalkenes, in high enantioselectivities and without requiring inert atmosphere conditions. The title catalysts, [Co((S,S)-dpen)3](3+) ((S,S)-3 (3+)) 3X(-), employ a commercially available chiral ligand, (S,S)-1,2-diphenylethylenediamine. The rates and ee values are functions of the configuration of the cobalt center (Λ/Δ) and the counteranions, which must be lipophilic to solubilize the trication in nonaqueous media. The highest enantioselectivities are obtained with Λ and 2Cl(-)BArf (-), 2BF4 (-)BArf (-), or 3BF4 (-) salts (BArf (-) = B(3,5-C6H3(CF3)2)4 (-)). The substrates are not activated by metal coordination, but rather by second coordination sphere hydrogen bonding involving the ligating NH2 groups. Crystal structures and NMR data indicate enthalpically stronger interactions with the NH moieties related by the C3 symmetry axis, as opposed to those related by the C2 symmetry axes; rate trends and other observations suggest this to be the catalytically active site. Both Λ- and Δ-(S,S)-3 (3+) 2Cl(-)BArf (-) are effective catalysts for additions of β-ketoesters to RO2CN=NCO2R species (99-86% yields, 81-76% ee), which provide carbon-nitrogen bonds and valuable precursors to α-amino acids. PMID:27162946

  14. Cardioprotective effects and pharmacokinetic properties of a controlled release formulation of a novel hydrogen sulfide donor in rats with acute myocardial infarction

    PubMed Central

    Tran, Ba Hieu; Huang, Chengrong; Zhang, Qiuyan; Liu, Xu; Lin, Shizhou; Liu, Hongrui; Wang, Shujun; Zhu, Yi Zhun

    2015-01-01

    We previously reported that S-propargyl-cysteine (SPRC) exerts cardioprotective effects by elevating H2S levels via the CSE/H2S pathway. In the present study, we investigated the cardioprotective effects and pharmacokinetic properties of a controlled release formulation of SPRC (CR-SPRC) in an in vivo rat model of myocardial infarction (MI). Rats were randomly assigned to seven groups that were pre-treated with CR-SPRC daily for 7 days prior to ligation of the left anterior descending coronary artery to induce MI. Cardiac function and infarct size were determined after MI, and we examined the activity of antioxidant enzymes, expression of anti-inflammation proteins and hydrogen sulfide levels. Mixed-mode, reversed-phase and cation-exchange HPLC–MS/MS were used to compare the pharmacokinetic properties of CR-SPRC and SPRC. CR-SPRC significantly reduced infarct size and creatine kinase (CK) and lactate dehydrogenase (LDH) leakage and it preserved cardiac function during MI. CR-SPRC displayed antioxidant properties, preserving glutathione (GSH), catalase (CAT) and superoxide dismutase (SOD) levels whereas reducing malondialdehyde (MDA) levels. Moreover, CR-SPRC significantly reduced the protein levels of inflammatory biomarkers (phospho-NF-κB p65/NF-κB p65, TNF-α) and increased cystathionine-γ-lyase (CSE) and Iκ-Bα protein levels. CR-SPRC had better pharmacokinetic properties than SPRC, with a reduced concentration peak (Cmax), prolonged time to reach peak concentration (Tmax), prolonged mean residence time (MRTinf) and increased AUC0–t. CR-SPRC showed protective effects against MI via the CSE/H2S pathway and demonstrated better cardioprotective effects than SPRC by prolonging the release of endogenous H2S. PMID:26182378

  15. Donor Tag Game

    MedlinePlus

    ... Cross chapter closest to you. Can't Donate Blood? A financial donation can also help save lives. Donate Now Find ... Donation Student Donors Donation Process Eligibility Blood FAQs Blood Donor Community Learn About Blood Blood Facts and Statistics ...

  16. Becoming a Donor

    MedlinePlus

    ... by Organ and Gender. > U.S. Waiting List Candidate Data HOW TO BECOME A DONOR The most important thing to do is to sign up as an organ and tissue donor in your state's donor registry. To cover all bases, it's also helpful to: Designate your decision on ...

  17. Hydrogen Bibliography

    SciTech Connect

    Not Available

    1991-12-01

    The Hydrogen Bibliography is a compilation of research reports that are the result of research funded over the last fifteen years. In addition, other documents have been added. All cited reports are contained in the National Renewable Energy Laboratory (NREL) Hydrogen Program Library.

  18. Donor corneal tissue evaluation.

    PubMed

    Saini, J S; Reddy, M K; Sharma, S; Wagh, S

    1996-03-01

    Proper evaluation of donor cornea is critical to the success of corneal transplantation. Attention must be paid to the cause of death and ocular condition as several general and ocular diseases constitute contraindications for donor corneal usage. Death to enucleation time should be noted. Gross examination and slit lamp biomicroscopy are mandatory for the evaluation of the donor eye while specular microscopy adds another useful dimension to information regarding donor cornea. This article provides a comprehensive review of all the aspects of donor corneal evaluation as practised today worldwide. PMID:8828299

  19. [Altruism and the donor].

    PubMed

    Langlois, A

    1991-08-01

    On December 20, 1988, the government of France passed a law to protect people who voluntarily participate in biomedical research. This article makes extensive reference to a major study, titled From Biology to Ethics, by Jean Bernard, a well-respected authority in the field of bioethics. The author looks at models proposed by Bernard, as examples for health volunteers, in particular, the blood donor and the self-experimenter. To set the tone of the article, she recalls the concept of altruism, as first proposed by Auguste Comte, then makes a linkage between his philosophy and Bernard's point of view. By trial and error, in their discussions, various ethics committees and the French State Council have agreed upon what constitutes fair compensation under the law. Unlike their Canadian counterparts, medical researchers in France have free access to volunteers who are not in perfect health--e.g., the elderly, people suffering from kidney deficiency, cirrhosis of the liver, etc.--but these "experimental subjects" receive no monetary compensation. Thus, healthy and less-than-healthy volunteers do not receive equal treatment under the law. This inequity, added to the fear of what amounts to a tax on the human body and the difficulty of ensuring just compensation, is giving rise to a great deal of uncertainty. PMID:1878857

  20. Laparoscopic live donor nephrectomy.

    PubMed

    Hasan, Waleed A; Al-Akraa, Mahmoud M

    2005-07-01

    With the number of patients presently awaiting renal transplantation exceeding the number of cadaveric organs available, there is an increasing reliance on live renal donation. Of the 11,869 renal transplants performed in 2002 in the US, 52.6% were living donors from the United Network for Organ Sharing Registry. Renal allografts from living donors provide: superior immediate long-term function; require less waiting time and are more cost-effective than those from cadaveric donors. However, anticipation of postoperative pain and temporary occupational disability may dissuade many potential donors. Additionally, some recipients hesitate to accept a living donor kidney due to suffering that would be endured by the donor. It is a unique medical situation when a young, completely healthy donor undergoes a major surgical procedure to provide an organ for transplantation. It is mandatory to offer a surgical technique, which is safe and with minimal complications. It is also obvious for any organ transplantation, that the integrity of the organ remain intact, thus, enabling its successful transplantation into the recipient. An acceptably short ischemia time and adequate lengths of ureter and renal vasculature are favored. Many centers are performing laparoscopic live donor nephrectomy in an effort to ease convalescence of renal donors. This may encourage the consideration of live donation by recipients and potential donors. PMID:16047050

  1. Lung donor selection criteria

    PubMed Central

    Chaney, John; Suzuki, Yoshikazu; Cantu, Edward

    2014-01-01

    The criteria that define acceptable physiologic and social parameters for lung donation have remained constant since their empiric determination in the 1980s. These criteria include a donor age between 25-40, a arterial partial pressure of oxygen (PaO2)/FiO2 ratio greater than 350, no smoking history, a clear chest X-ray, clean bronchoscopy, and a minimal ischemic time. Due to the paucity of organ donors, and the increasing number of patients requiring lung transplant, finding a donor that meets all of these criteria is quite rare. As such, many transplants have been performed where the donor does not meet these stringent criteria. Over the last decade, numerous reports have been published examining the effects of individual acceptance criteria on lung transplant survival and graft function. These studies suggest that there is little impact of the historical criteria on either short or long term outcomes. For age, donors should be within 18 to 64 years old. Gender may relay benefit to all female recipients especially in male to female transplants, although results are mixed in these studies. Race matched donor/recipients have improved outcomes and African American donors convey worse prognosis. Smoking donors may decrease recipient survival post transplant, but provide a life saving opportunity for recipients that may otherwise remain on the transplant waiting list. No specific gram stain or bronchoscopic findings are reflected in recipient outcomes. Chest radiographs are a poor indicator of lung donor function and should not adversely affect organ usage aside for concerns over malignancy. Ischemic time greater than six hours has no documented adverse effects on recipient mortality and should not limit donor retrieval distances. Brain dead donors and deceased donors have equivalent prognosis. Initial PaO2/FiO2 ratios less than 300 should not dissuade donor organ usage, although recruitment techniques should be implemented with intent to transplant. PMID:25132970

  2. Lung donor selection criteria.

    PubMed

    Chaney, John; Suzuki, Yoshikazu; Cantu, Edward; van Berkel, Victor

    2014-08-01

    The criteria that define acceptable physiologic and social parameters for lung donation have remained constant since their empiric determination in the 1980s. These criteria include a donor age between 25-40, a arterial partial pressure of oxygen (PaO2)/FiO2 ratio greater than 350, no smoking history, a clear chest X-ray, clean bronchoscopy, and a minimal ischemic time. Due to the paucity of organ donors, and the increasing number of patients requiring lung transplant, finding a donor that meets all of these criteria is quite rare. As such, many transplants have been performed where the donor does not meet these stringent criteria. Over the last decade, numerous reports have been published examining the effects of individual acceptance criteria on lung transplant survival and graft function. These studies suggest that there is little impact of the historical criteria on either short or long term outcomes. For age, donors should be within 18 to 64 years old. Gender may relay benefit to all female recipients especially in male to female transplants, although results are mixed in these studies. Race matched donor/recipients have improved outcomes and African American donors convey worse prognosis. Smoking donors may decrease recipient survival post transplant, but provide a life saving opportunity for recipients that may otherwise remain on the transplant waiting list. No specific gram stain or bronchoscopic findings are reflected in recipient outcomes. Chest radiographs are a poor indicator of lung donor function and should not adversely affect organ usage aside for concerns over malignancy. Ischemic time greater than six hours has no documented adverse effects on recipient mortality and should not limit donor retrieval distances. Brain dead donors and deceased donors have equivalent prognosis. Initial PaO2/FiO2 ratios less than 300 should not dissuade donor organ usage, although recruitment techniques should be implemented with intent to transplant. PMID:25132970

  3. Value Added?

    ERIC Educational Resources Information Center

    UCLA IDEA, 2012

    2012-01-01

    Value added measures (VAM) uses changes in student test scores to determine how much "value" an individual teacher has "added" to student growth during the school year. Some policymakers, school districts, and educational advocates have applauded VAM as a straightforward measure of teacher effectiveness: the better a teacher, the better students…

  4. Rich Donors, Poor Countries

    ERIC Educational Resources Information Center

    Thomas, M. A.

    2012-01-01

    The shifting ideological winds of foreign aid donors have driven their policy towards governments in poor countries. Donors supported state-led development policies in poor countries from the 1940s to the 1970s; market and private-sector driven reforms during the 1980s and 1990s; and returned their attention to the state with an emphasis on…

  5. Donor Telomere Length SAA

    Cancer.gov

    A new NCI study has found that, among patients with severe aplastic anemia who received a hematopoietic cell transplant from an unrelated donor, those whose donor white blood cells had longer telomeres had higher survival rates five-years after transplant

  6. Donor selection and management.

    PubMed

    Snell, Gregory I; Paraskeva, Miranda; Westall, Glen P

    2013-06-01

    This article reviews recent developments in the selection, assessment, and management of the potential lung donor, which aim to increase donor organ use. The scarcity of suitable donor organs continues to limit lung transplantation, but the situation is changing. An expanded donor pool, including the now widespread use of donation after cardiac death (DCD) lungs; the use of extended donor lungs; and the ability of ex vivo lung perfusion (EVLP) to evaluate and improve donor lungs are key initiatives. These strategies have substantially lifted donor lung utilization rates from historically low levels of less than 15% to rates greater than 50%. Indeed, since 2004 there has been an accelerated year-on-year increase in the number of lungs transplanted globally. Intermediate-term studies are now confirming that long-term outcomes are not being significantly compromised and that more individuals with terminal, symptomatic lung disease are being transplanted. It is now quite clear that many of the historical factors used to define a lung as "extended" do not actually produce significantly inferior outcomes. There has been a dramatic increase in research and clinical interest in donor lung assessment, management, and novel therapeutic strategies. The lessons learned are now being applied widely beyond the lung as researchers aim to increase availability and optimize other solid organs for transplantation. PMID:23821510

  7. A brown dwarf mass donor in an accreting binary.

    PubMed

    Littlefair, S P; Dhillon, V S; Marsh, T R; Gänsicke, Boris T; Southworth, John; Watson, C A

    2006-12-01

    A long-standing and unverified prediction of binary star evolution theory is the existence of a population of white dwarfs accreting from substellar donor stars. Such systems ought to be common, but the difficulty of finding them, combined with the challenge of detecting the donor against the light from accretion, means that no donor star to date has a measured mass below the hydrogen burning limit. We applied a technique that allowed us to reliably measure the mass of the unseen donor star in eclipsing systems. We were able to identify a brown dwarf donor star, with a mass of 0.052 +/- 0.002 solar mass. The relatively high mass of the donor star for its orbital period suggests that current evolutionary models may underestimate the radii of brown dwarfs. PMID:17158322

  8. Adding Value.

    ERIC Educational Resources Information Center

    Orsini, Larry L.; Hudack, Lawrence R.; Zekan, Donald L.

    1999-01-01

    The value-added statement (VAS), relatively unknown in the United States, is used in financial reports by many European companies. Saint Bonaventure University (New York) has adapted a VAS to make it appropriate for not-for-profit universities by identifying stakeholder groups (students, faculty, administrators/support personnel, creditors, the…

  9. Living Donor Liver Transplantation

    MedlinePlus

    ... around the scar. The bulges can usually be fixed with surgery. During your medical exam, ask the ... to find out if the donor's blood type matches the recipient’s blood type. Next, the transplant team ...

  10. DIS in AdS

    NASA Astrophysics Data System (ADS)

    Albacete, Javier L.; Kovchegov, Yuri V.; Taliotis, Anastasios

    2009-03-01

    We calculate the total cross section for the scattering of a quark-anti-quark dipole on a large nucleus at high energy for a strongly coupled N = 4 super Yang-Mills theory using AdS/CFT correspondence. We model the nucleus by a metric of a shock wave in AdS5. We then calculate the expectation value of the Wilson loop (the dipole) by finding the extrema of the Nambu-Goto action for an open string attached to the quark and antiquark lines of the loop in the background of an AdS5 shock wave. We find two physically meaningful extremal string configurations. For both solutions we obtain the forward scattering amplitude N for the quark dipole-nucleus scattering. We study the onset of unitarity with increasing center-of-mass energy and transverse size of the dipole: we observe that for both solutions the saturation scale Qs is independent of energy/Bjorken-x and depends on the atomic number of the nucleus as Qs˜A1/3. Finally we observe that while one of the solutions we found corresponds to the pomeron intercept of αP = 2 found earlier in the literature, when extended to higher energy or larger dipole sizes it violates the black disk limit. The other solution we found respects the black disk limit and yields the pomeron intercept of αP = 1.5. We thus conjecture that the right pomeron intercept in gauge theories at strong coupling may be αP = 1.5.

  11. Laparoscopic donor nephrectomy.

    PubMed

    Deger, S; Giessing, M; Roigas, J; Wille, A H; Lein, M; Schönberger, B; Loening, S A

    2005-01-01

    Laparoscopic live donor nephrectomy (LDN) has removed disincentives of potential donors and may bear the potential to increase kidney donation. Multiple modifications have been made to abbreviate the learning curve while at the same time guarantee the highest possible level of medical quality for donor and recipient. We reviewed the literature for the evolution of the different LDN techniques and their impact on donor, graft and operating surgeon, including the subtleties of different surgical accesses, vessel handling and organ extraction. We performed a literature search (PubMed, DIMDI, medline) to evaluate the development of the LDN techniques from 1995 to 2003. Today more than 200 centres worldwide perform LDN. Hand-assistance has led to a spread of LDN. Studies comparing open and hand-assisted LDN show a reduction of operating and warm ischaemia times for the hand-assisted LDN. Different surgical access sites (trans- or retroperitoneal), different vessel dissection approaches, donor organ delivery techniques, delivery sites and variations of hand-assistance techniques reflect the evolution of LDN. Proper techniques and their combination for the consecutive surgical steps minimize both warm ischaemia time and operating time while offering the donor a safe minimally invasive laparoscopic procedure. LDN has breathed new life into the moribund field of living kidney donation. Within a few years LDN could become the standard approach in living kidney donation. Surgeons working in this field must be trained thoroughly and well acquainted with the subtleties of the different LDN techniques and their respective advantages and disadvantages. PMID:16754618

  12. Live-donor nephrectomy.

    PubMed

    Rocca, Juan P; Davis, Eric; Edye, Michael

    2012-01-01

    Six decades after its first implementation, kidney transplantation remains the optimal therapy for end-stage renal disease requiring dialysis. Despite the incontrovertible mortality reduction and cost-effectiveness of kidney transplantation, the greatest remaining barrier to treatment of end-stage renal disease is organ availability. Although the waiting list of patients who stand to benefit from kidney transplantation grows at a rate proportional to the overall population and proliferation of diabetes and hypertension, the pool of deceased-donor organs available for transplantation experiences minimal to no growth. Because the kidney is uniquely suited as a paired organ, the transplant community's answer to this shortage is living donation of a healthy volunteer's kidney to a recipient with end-stage renal disease. This review details the history and evolution of living-donor kidney transplantation in the United States as well as advances the next decade promises. Laparoscopic donor nephrectomy has overcome many of the obstacles to living donation in terms of donor morbidity and volunteerism. Known donor risks in terms of surgical and medical morbidity are reviewed, as well as the ongoing efforts to delineate and mitigate donor risk in the context of accumulating recipient morbidity while on the waiting list. PMID:22678857

  13. Absence of beta-amyloid in cortical cataracts of donors with and without Alzheimer's disease.

    PubMed

    Michael, Ralph; Rosandić, Jurja; Montenegro, Gustavo A; Lobato, Elvira; Tresserra, Francisco; Barraquer, Rafael I; Vrensen, Gijs F J M

    2013-01-01

    Eye lenses from human donors with and without Alzheimer's disease (AD) were studied to evaluate the presence of amyloid in cortical cataract. We obtained 39 lenses from 21 postmortem donors with AD and 15 lenses from age-matched controls provided by the Banco de Ojos para Tratamientos de la Ceguera (Barcelona, Spain). For 17 donors, AD was clinically diagnosed by general physicians and for 4 donors the AD diagnosis was neuropathologically confirmed. Of the 21 donors with AD, 6 had pronounced bilateral cortical lens opacities and 15 only minor or no cortical opacities. As controls, 7 donors with pronounced cortical opacities and 8 donors with almost transparent lenses were selected. All lenses were photographed in a dark field stereomicroscope. Histological sections were analyzed using a standard and a more sensitive Congo red protocol, thioflavin staining and beta-amyloid immunohistochemistry. Brain tissue from two donors, one with cerebral amyloid angiopathy and another with advanced AD-related changes and one cornea with lattice dystrophy were used as positive controls for the staining techniques. Thioflavin, standard and modified Congo red staining were positive in the control brain tissues and in the dystrophic cornea. Beta-amyloid immunohistochemistry was positive in the brain tissues but not in the cornea sample. Lenses from control and AD donors were, without exception, negative after Congo red, thioflavin, and beta-amyloid immunohistochemical staining. The results of the positive control tissues correspond well with known observations in AD, amyloid angiopathy and corneas with lattice dystrophy. The absence of staining in AD and control lenses with the techniques employed lead us to conclude that there is no beta-amyloid in lenses from donors with AD or in control cortical cataracts. The inconsistency with previous studies of Goldstein et al. (2003) and Moncaster et al. (2010), both of which demonstrated positive Congo red, thioflavin, and beta

  14. Distinctive Characteristics of Educational Donors

    ERIC Educational Resources Information Center

    James, Russell N., III.

    2008-01-01

    Examining the charitable behavior of 56,663 US households, this paper evaluates the distinctive characteristics of educational donors as compared with donors to noneducational charitable organizations and with nondonors. In general, educational donors had significantly greater income, wealth, and education than other donors. Educational donors…

  15. Systems of donor transfer.

    PubMed

    de Charro, F T; Akveld, H E; Hessing, D J

    1993-10-01

    The development of medical knowledge has resulted in a demand in society for donor organs, but the recruitment of donor organs for transplantation is difficult. This paper aims to provide some general insights into the complex interaction processes involved. A laissez-faire policy, in which market forces are relied on, is not acceptable from an ethical and legal point of view in most western European countries. Especially at the demand side of the exchange of donor organs, commercialism is to be opposed. We judge the use of commercial incentives at the supply side less unacceptable in theory but not feasible in western European countries. Since market forces are deemed unacceptable as instruments for coordinating demand and supply of donor organs, donor procurement has to be considered as a collective good, and therefore governments are faced with the responsibility of making sure that alternative interaction and distribution mechanisms function. The role of organ procurement agencies (OPAs) in societal interaction concerning postmortem organ donation is described using a two-dimensional conceptualisation scheme. Medical aspects of living organ donation are described. An international comparative description of legal systems to regulate living organ donation in western European countries completes this survey. PMID:10129766

  16. Independent donor ethical assessment: aiming to standardize donor advocacy.

    PubMed

    Choudhury, Devasmita; Jotterand, Fabrice; Casenave, Gerald; Smith-Morris, Carolyn

    2014-06-01

    Living organ donation has become more common across the world. To ensure an informed consent process, given the complex issues involved with organ donation, independent donor advocacy is required. The choice of how donor advocacy is administered is left up to each transplant center. This article presents the experience and process of donor advocacy at University of Texas Southwestern Medical Center administered by a multidisciplinary team consisting of physicians, surgeons, psychologists, medical ethicists and anthropologists, lawyers, a chaplain, a living kidney donor, and a kidney transplant recipient. To ensure that advocacy remains fair and consistent for all donors being considered, the donor advocacy team at University of Texas Southwestern Medical Center developed the Independent Donor Ethical Assessment, a tool that may be useful to others in rendering donor advocacy. In addition, the tool may be modified as circumstances arise to improve donor advocacy and maintain uniformity in decision making. PMID:24919733

  17. Managing finances of shipping living donor kidneys for donor exchanges.

    PubMed

    Mast, D A; Vaughan, W; Busque, S; Veale, J L; Roberts, J P; Straube, B M; Flores, N; Canari, C; Levy, E; Tietjen, A; Hil, G; Melcher, M L

    2011-09-01

    Kidney donor exchanges enable recipients with immunologically incompatible donors to receive compatible living donor grafts; however, the financial management of these exchanges, especially when an organ is shipped, is complex and thus has the potential to impede the broader implementation of donor exchange programs. Representatives from transplant centers that utilize the National Kidney Registry database to facilitate donor exchange transplants developed a financial model applicable to paired donor exchanges and donor chain transplants. The first tenet of the model is to eliminate financial liability to the donor. Thereafter, it accounts for the donor evaluation, donor nephrectomy hospital costs, donor nephrectomy physician fees, organ transport, donor complications and recipient inpatient services. Billing between hospitals is based on Medicare cost report defined costs rather than charges. We believe that this model complies with current federal regulations and effectively captures costs of the donor and recipient services. It could be considered as a financial paradigm for the United Network for Organ Sharing managed donor exchange program. PMID:21831153

  18. DIS in AdS

    SciTech Connect

    Albacete, Javier L.; Kovchegov, Yuri V.; Taliotis, Anastasios

    2009-03-23

    We calculate the total cross section for the scattering of a quark-anti-quark dipole on a large nucleus at high energy for a strongly coupled N = 4 super Yang-Mills theory using AdS/CFT correspondence. We model the nucleus by a metric of a shock wave in AdS{sub 5}. We then calculate the expectation value of the Wilson loop (the dipole) by finding the extrema of the Nambu-Goto action for an open string attached to the quark and antiquark lines of the loop in the background of an AdS{sub 5} shock wave. We find two physically meaningful extremal string configurations. For both solutions we obtain the forward scattering amplitude N for the quark dipole-nucleus scattering. We study the onset of unitarity with increasing center-of-mass energy and transverse size of the dipole: we observe that for both solutions the saturation scale Q{sub s} is independent of energy/Bjorken-x and depends on the atomic number of the nucleus as Q{sub s}{approx}A{sup 1/3}. Finally we observe that while one of the solutions we found corresponds to the pomeron intercept of {alpha}{sub P} = 2 found earlier in the literature, when extended to higher energy or larger dipole sizes it violates the black disk limit. The other solution we found respects the black disk limit and yields the pomeron intercept of {alpha}{sub P} = 1.5. We thus conjecture that the right pomeron intercept in gauge theories at strong coupling may be {alpha}{sub P} = 1.5.

  19. Bubbling AdS3

    NASA Astrophysics Data System (ADS)

    Martelli, Dario; Morales, Jose F.

    2005-02-01

    In the light of the recent Lin, Lunin, Maldacena (LLM) results, we investigate 1/2-BPS geometries in minimal (and next to minimal) supergravity in D = 6 dimensions. In the case of minimal supergravity, solutions are given by fibrations of a two-torus T2 specified by two harmonic functions. For a rectangular torus the two functions are related by a non-linear equation with rare solutions: AdS3 × S3, the pp-wave and the multi-center string. ``Bubbling'', i.e. superpositions of droplets, is accommodated by allowing the complex structure of the T2 to vary over the base. The analysis is repeated in the presence of a tensor multiplet and similar conclusions are reached, with generic solutions describing D1D5 (or their dual fundamental string-momentum) systems. In this framework, the profile of the dual fundamental string-momentum system is identified with the boundaries of the droplets in a two-dimensional plane.

  20. Evaluation of the donor ability of coal liquefaction solvents

    SciTech Connect

    Bockrath, B.C.; Noceti, R.P.

    1981-03-29

    A test was devised to evaluate the donor ability of coal liquefaction solvents. This test embodies the main features of the free radical mechanism of coal liquefaction. Benzyl radicals generated by the thermolysis of a convenient precursor at relatively low temperatures behave like the free radicals generated by the thermolysis of coal at liquefaction temperatures. As precursors for this test, dibenzyldiazene and dibenzylmercury were selected. When benzyl radicals are generated in a donor solvent, the relative amounts of toluene and bibenzyl produced reflect the relative ability of the solvent to donate hydrogen and to prevent recombination. A variable amount of benzyl radical is also lost, which presumably represents that amount which adds to or combines with the solvent. Experimental evidences have shown that an additional mode of action of donor solvent is that of free radical scavenger by combination and addition reactions. Accordingly, three indices were devised to compare donor solvents: the donor, the scavenger, and combined index. The three solvent indices were determined for the decomposition of dibenzylmercury for several solvent mixtures made from different amounts of tetralin (solvent) in t-butyl benzene. The data show that the donor index increases with increasing tetralin concentration. A series of model compounds were evaluated using dibenzyldiazene as the source of benzyl radical, and results are tabulated. Another table is presented which show the donor indices obtained for several coal-derived liquefaction solvents. Taken together, these data indicate that there is good qualitative agreement between liquefaction performance and the donor index of solvents.

  1. Dialing for Donors

    ERIC Educational Resources Information Center

    Schaffhauser, Dian

    2012-01-01

    When times get tough, grown children often turn to their parents for help--for some extra cash, even somewhere to stay. For colleges and universities, that role is filled by alumni donors. In 2011, with education budgets slashed across the country, giving accounted for 6.5 percent of college expenditures, according to the Council for Aid to…

  2. Understanding donors' motivations: a study of unrelated bone marrow donors.

    PubMed

    Switzer, G E; Dew, M A; Butterworth, V A; Simmons, R G; Schimmel, M

    1997-07-01

    Medical advances in bone marrow transplantation techniques and immunosuppressive medications have dramatically increased the number of such transplants performed each year, and consequently, the demand for bone marrow from unrelated donors. Although physiological aspects of bone marrow donation have been thoroughly investigated, very few studies have examined psychosocial factors that may impact individuals' donation decisions and outcomes. To examine one particular set of donor psychosocial issues, this study investigated motives for bone marrow donation among 343 unrelated bone marrow donors who donated through the National Marrow Donor Program. Six distinct types of donor motives were identified from open-ended questionnaire responses. Donors most frequently reported motives reflecting some awareness of both the costs (to themselves) and potential benefits (to themselves and the recipient) of donation. A desire to act in accordance with social or religious precepts, expected positive feelings about donating, empathy for the recipient, and the simple desire to help another person were also commonly cited reasons for donating. Among a series of donor background characteristics, donors' gender was the variable most strongly associated with motive type; women were most likely to cite expected positive feelings, empathy, and the desire to help someone. Central study findings indicated that donor motives predicted donors reactions to donation even after the effects of donor background characteristics (including gender) were controlled. Donors who reported exchange motives (weighing costs and benefits) and donors who reported simple (or idealized) helping motives experienced the donation as less positive in terms of higher predonation ambivalence and negative postdonation psychological reactions than did remaining donors. Donors who reported positive feeling and empathy motives had the most positive donation reactions in terms of lower ambivalence, and feeling like

  3. Being a Living Donor: Risks

    MedlinePlus

    ... surgical risks and long term complications: Long-Term Organ Specific Donor Complications Kidney Hypertension Kidney failure Proteinuria Lung Intra- ... Vancouver Forum on the care of the live organ donor: lung, liver, pancreas, and intestine data and medical ...

  4. Hyperfine Stark effect of shallow donors in silicon

    NASA Astrophysics Data System (ADS)

    Pica, Giuseppe; Wolfowicz, Gary; Urdampilleta, Matias; Thewalt, Mike L. W.; Riemann, Helge; Abrosimov, Nikolai V.; Becker, Peter; Pohl, Hans-Joachim; Morton, John J. L.; Bhatt, R. N.; Lyon, S. A.; Lovett, Brendon W.

    2014-11-01

    We present a complete theoretical treatment of Stark effects in bulk doped silicon, whose predictions are supported by experimental measurements. A multivalley effective mass theory, dealing nonperturbatively with valley-orbit interactions induced by a donor-dependent central cell potential, allows us to obtain a very reliable picture of the donor wave function within a relatively simple framework. Variational optimization of the 1 s donor binding energies calculated with a new trial wave function, in a pseudopotential with two fitting parameters, allows an accurate match of the experimentally determined donor energy levels, while the correct limiting behavior for the electronic density, both close to and far from each impurity nucleus, is captured by fitting the measured contact hyperfine coupling between the donor nuclear and electron spin. We go on to include an external uniform electric field in order to model Stark physics: with no extra ad hoc parameters, variational minimization of the complete donor ground energy allows a quantitative description of the field-induced reduction of electronic density at each impurity nucleus. Detailed comparisons with experimental values for the shifts of the contact hyperfine coupling reveal very close agreement for all the donors measured (P, As, Sb, and Bi). Finally, we estimate field ionization thresholds for the donor ground states, thus setting upper limits to the gate manipulation times for single qubit operations in Kane-like architectures: the Si:Bi system is shown to allow for A gates as fast as ≈10 MHz.

  5. Donor commitment and patient needs.

    PubMed

    Bakken, R; van Walraven, A-M; Egeland, T

    2004-01-01

    The article discusses views and recommendations of the World Marrow Donor Association concerning ethical issues related to the donation of hematopoietic stem cell products with respect to recruitment, evaluation, workup, and follow-up of unrelated donors. Particular emphasis is placed upon commitment of individual donors, in particular, with respect to the needs of patients to find HLA-matched donors, who may be asked to donate stem cell and other cell products more than once for given patients. PMID:14628078

  6. Why Minority Donors Are Needed

    MedlinePlus

    ... Español Search Register with your state as an Organ Donor Home Why Donate Becoming a Donor About Donation & ... Why Donate RELATED INFORMATION Minority Focused Grantee Publications Organ Donation Process Enrolling as a Donor Trying to Save a Life Testing for Brain ...

  7. Biological hydrogen photoproduction

    SciTech Connect

    Nemoto, Y.

    1995-09-01

    Following are the major accomplishments of the 6th year`s study of biological hydrogen photoproduction which were supported by DOE/NREL. (1) We have been characterizing a biological hydrogen production system using synchronously growing aerobically nitrogen-fixing unicellular cyanobacterium, Synechococcus sp. Miami BG 043511. So far it was necessary to irradiate the cells to produce hydrogen. Under darkness they did not produce hydrogen. However, we found that, if the cells are incubated with oxygen, they produce hydrogen under the dark. Under 80% argon + 20% oxygen condition, the hydrogen production activity under the dark was about one third of that under the light + argon condition. (2) Also it was necessary so far to incubate the cells under argon atmosphere to produce hydrogen in this system. Argon treatment is very expensive and should be avoided in an actual hydrogen production system. We found that, if the cells are incubated at a high cell density and in a container with minimum headspace, it is not necessary to use argon for the hydrogen production. (3) Calcium ion was found to play an important role in the mechanisms of protection of nitrogenase from external oxygen. This will be a clue to understand the reason why the hydrogen production is so resistant to oxygen in this strain. (4) In this strain, sulfide can be used as electron donor for the hydrogen production. This result shows that waste water can be used for the hydrogen production system using this strain.

  8. Confidentiality and American semen donors.

    PubMed

    Karow, A M

    1993-01-01

    Most American donor insemination programs include a policy of complete confidentiality concerning the donor of the semen. This is the result of a long legal tradition of American constitutional law. However, some slight abridgement of this body of legal decisions might be very much in the best interests of children arising from donor insemination, and even--in most cases, in fact--the donors themselves. With regard to the children, the factors involved are both those of genetic counseling, should the need arise, and psychological development. Of course, as at present, the donor must be relieved of all responsibility, both legal and financial. PMID:8348162

  9. Blood Donor Management in China

    PubMed Central

    Shi, Ling; Wang, Jingxing; Liu, Zhong; Stevens, Lori; Sadler, Andrew; Ness, Paul; Shan, Hua

    2014-01-01

    Summary Despite a steady increase in total blood collections and voluntary non-remunerated blood donors, China continues to have many challenges with its blood donation system. The country's donation rate remains low at 9%o, with over 60% of donors being first-time donors. Generally there is a lack of adequate public awareness about blood donation. The conservative donor selection criteria, the relatively long donation interval, and the small donation volume have further limited blood supply. To ensure a sufficient and safe blood supply that meets the increasing clinical need for blood products, there is an urgent need to strengthen the country's blood donor management. This comprehensive effort should include educating and motivating more individuals especially from the rural areas to be involved in blood donation, developing rational and evidence-based selection criteria for donor eligibility, designing a donor follow-up mechanism to encourage more future donations, assessing the current donor testing strategy, improving donor service and care, building regional and national shared donor deferral database, and enhancing the transparency of the blood donation system to gain more trust from the general public. The purpose of the review is to provide an overview of the key process of and challenges with the blood donor management system in China. PMID:25254023

  10. Blood donor management in china.

    PubMed

    Shi, Ling; Wang, Jingxing; Liu, Zhong; Stevens, Lori; Sadler, Andrew; Ness, Paul; Shan, Hua

    2014-07-01

    Despite a steady increase in total blood collections and voluntary non-remunerated blood donors, China continues to have many challenges with its blood donation system. The country's donation rate remains low at 9%o, with over 60% of donors being first-time donors. Generally there is a lack of adequate public awareness about blood donation. The conservative donor selection criteria, the relatively long donation interval, and the small donation volume have further limited blood supply. To ensure a sufficient and safe blood supply that meets the increasing clinical need for blood products, there is an urgent need to strengthen the country's blood donor management. This comprehensive effort should include educating and motivating more individuals especially from the rural areas to be involved in blood donation, developing rational and evidence-based selection criteria for donor eligibility, designing a donor follow-up mechanism to encourage more future donations, assessing the current donor testing strategy, improving donor service and care, building regional and national shared donor deferral database, and enhancing the transparency of the blood donation system to gain more trust from the general public. The purpose of the review is to provide an overview of the key process of and challenges with the blood donor management system in China. PMID:25254023

  11. Hydrogen-bonding interactions in adrenaline-water complexes: DFT and QTAIM studies of structures, properties, and topologies.

    PubMed

    Wang, Hongke; Huang, Zhengguo; Shen, Tingting; Guo, Lingfei

    2012-07-01

    ωB97XD/6-311++G(d,p) calculations were carried out to investigate the hydrogen-bonding interactions between adrenaline (Ad) and water. Six Ad-H(2)O complexes possessing various types of hydrogen bonds (H-bonds) were characterized in terms of their geometries, energies, vibrational frequencies, and electron-density topology. Natural bond orbital (NBO) and quantum theory of atoms in molecules (QTAIM) analyses were performed to elucidate the nature of the hydrogen-bonding interactions in these complexes. The intramolecular H-bond between the amino and carboxyl oxygen atom of Ad was retained in most of the complexes, and cooperativity between the intra- and intermolecular H-bonds was present in some of the complexes. H-bonds in which hydroxyls of Ad/water acted as proton donors were stronger than other H-bonds. Both hydrogen-bonding interactions and structural deformation play important roles in the relative stabilities of the complexes. The intramolecular H-bond was broken during the formation of the most stable complex, which indicates that Ad tends to break the intramolecular H-bond and form two new intermolecular H-bonds with the first water molecule. PMID:22212733

  12. Production of native donors in ZnO by annealing at high temperature in Zn vapor

    NASA Astrophysics Data System (ADS)

    Halliburton, L. E.; Giles, N. C.; Garces, N. Y.; Luo, Ming; Xu, Chunchuan; Bai, Lihai; Boatner, L. A.

    2005-10-01

    Zinc oxide crystals grown by the seeded chemical vapor transport method have been annealed in zinc vapor at 1100 °C for 30 min. These thermochemical reduction treatments produce a deep red coloration in the crystals and increase their n-type electrical conductivity. Electron paramagnetic resonance (EPR), optical absorption, and Hall measurements were used to monitor changes in the crystals. After an anneal, an intense optical absorption band is present that extends from the band edge out to approximately 550 nm, and the EPR signal near g =1.96 (due to shallow donors and/or conduction-band electrons), the free-carrier absorption, and the Hall electron concentration are all larger. Hydrogen was not present during these anneals, thus leaving oxygen vacancies and zinc interstitials as candidates for the added donors. Neutral oxygen vacancies are produced at high temperature by the additive-coloration mechanism, and are responsible for the broad near-edge absorption band. The observed increase in the number of free carriers is a result of either (1) the formation of zinc interstitials or (2) having the ground state of the neutral oxygen vacancy near the conduction band.

  13. Ubisemiquinone is the electron donor for superoxide formation by complex III of heart mitochondria.

    PubMed

    Turrens, J F; Alexandre, A; Lehninger, A L

    1985-03-01

    Much evidence indicates that superoxide is generated from O2 in a cyanide-sensitive reaction involving a reduced component of complex III of the mitochondrial respiratory chain, particularly when antimycin A is present. Although it is generally believed that ubisemiquinone is the electron donor to O2, little experimental evidence supporting this view has been reported. Experiments with succinate as electron donor in the presence of antimycin A in intact rat heart mitochondria, which contain much superoxide dismutase but little catalase, showed that myxothiazol, which inhibits reduction of the Rieske iron-sulfur center, prevented formation of hydrogen peroxide, determined spectrophotometrically as the H2O2-peroxidase complex. Similarly, depletion of the mitochondria of their cytochrome c also inhibited formation of H2O2, which was restored by addition of cytochrome c. These observations indicate that factors preventing the formation of ubisemiquinone also prevent H2O2 formation. They also exclude ubiquinol, which remains reduced under these conditions, as the reductant of O2. Since cytochrome b also remains fully reduced when myxothiazol is added to succinate- and antimycin A-supplemented mitochondria, reduced cytochrome b may also be excluded as the reductant of O2. These observations, which are consistent with the Q-cycle reactions, by exclusion of other possibilities leave ubisemiquinone as the only reduced electron carrier in complex III capable of reducing O2 to O2-. PMID:2983613

  14. Electric field control of donor pair diatomic molecules in silicon

    NASA Astrophysics Data System (ADS)

    Baena, Alejandra; Saraiva, Andre; Calderón, María J.; Koiller, Belita

    2015-03-01

    Single donors are well-established building blocks for engineering electronic properties of semiconductors, acting effectively as giant hydrogen atoms. Donor pairs, analogous to effective hydrogen molecules, were recently investigated in the strongly interacting regime in silicon. In this regime, electric field control renders timid results. Pairs that are more distant are more susceptible to external fields, and may harbour single electron charge control. Theoretically, the molecular quantum mechanics analogy between a donor pair and the H2 molecule in vacuum is not as straightforward as it may seem. A detailed understanding of the electronic structure of these molecular systems is a current challenge. We analyze the lowest energy states within effective mass theory, including central cell corrected donor potential effects and the conduction band multiplicity in Si. The spectrum of ionized donor pairs and its response to an external electric field will be presented. We contemplate possible advantages of heteropolar diatomic molecules, e.g, Sb -As pairs, as more efficient elements for such devices and applications.

  15. Oxygen, carbon, hydrogen and nitrogen in crystalline silicon

    SciTech Connect

    Mikkelsen, J.C.; Pearton, S.J.; Corbett, J.W.; Pennycook, S.J

    1986-01-01

    These proceedings collect papers on interstitial material in silicon. Topics include: hydrogen in crystalline silicon, low energy hydrogen ion bombarded silicon, oxygen in silicon, oxygen thermal donor formation, thermal donor generation and annihilation effects on oxygen precipitation oxygen effects on plastic flow during growth of dendrixic web silicon, nitrogen in silicon, off-center nitrogen and oxygen in silicon, and thermal donor hierarchies in silicon and germanium.

  16. The effect of a hydrogen sulfide releasing molecule (Na2S) on the cold storage of livers from cardiac dead donor rats. A study in an ex vivo model.

    PubMed

    Balaban, Cecilia Lucía; Rodríguez, Joaquín Valentín; Tiribelli, Claudio; Guibert, Edgardo Elvio

    2015-08-01

    Liver transplantation is currently the preferred treatment option for end-stage liver disease. Donation after cardiac death was a common practice in the early years of organ donation before brain death criteria were established. Those organs were subjected to variable periods of warm ischemia that might intensify cold ischemia/reperfusion injuries. In the present, shortage of brain dead donors has led to the reassessment of organ donation after cardiac death. Since many cytoprotective roles have been describe for H2S during ischemia/reperfusion on a variety of tissues, we hypothesized that graft exposure to this bioactive gas might improve preservation of non-heart beating donated organs. Therefore, to establish a rat model of donation post-cardiac arrest and using this approach to judge H2S delivery effects on graft hypothermic preservation, were the main objectives of this investigation. Cardiopulmonary arrest was induced in sedated rats by overload of potassium (K(+)). Livers were surgically removed and subsequently stored in HTK Solution (Histidine-tryptophan-ketoglutarate) at 0-4°C. After 24 h of hypothermic preservation, livers were rewarmed in an ex vivo model. Three experimental groups were established as follows: I--Livers procured before cardiac death and cold stored 24 h in HTK (BCD); II--Livers procured after cardiac death (45 min) and cold stored 24 h in HTK (ACD); III--Livers procured after cardiac death (45 min) and cold stored 24 h in HTK+10 μM Sodium Sulfide (Na2S) (ACD-SS). Data suggest that after 45 min of warm ischemia, viability parameters assessed during reperfusion in the ex vivo model were significantly impaired. Real time PCR revealed that after ex vivo reperfusion there is an increased expression of HO-1 and TNF-α and a modest drop in Bcl-2 mRNA, which could be interpreted as the cellular response to the hypoxic insult sustained during warm ischemia. On the other hand, warm ischemic livers exposed to H2S during cold storage, improved

  17. Alkyl Chlorides as Hydrogen Bond Acceptors

    SciTech Connect

    Nadas, Janos I; Vukovic, Sinisa; Hay, Benjamin

    2012-01-01

    To gain an understanding of the role of an alkyl chloride as a hydrogen bond acceptor, geometries and interaction energies were calculated at the MP2/aug-cc-pVDZ level of theory for complexes between ethyl chloride and representative hydrogen donor groups. The results establish that these donors, which include hydrogen cyanide, methanol, nitrobenzene, pyrrole, acetamide, and N-methylurea, form X-H {hor_ellipsis} Cl hydrogen bonds (X = C, N, O) of weak to moderate strength, with {Delta}E values ranging from -2.8 to -5.3 kcal/mol.

  18. Relationship between the broad OH stretching band of methanol and hydrogen-bonding patterns in the liquid phase.

    PubMed

    Ohno, Keiichi; Shimoaka, Takafumi; Akai, Nobuyuki; Katsumoto, Yukiteru

    2008-08-14

    The OH stretching (nu(OH)) band of methanol observed in condensed phase has been analyzed in terms of hydrogen-bonding patterns. Quantum chemical calculations for methanol clusters have revealed that broadening of the nu(OH) envelope is reasonably reproduced by considering nearest and next-nearest neighbor interactions through hydrogen bonding. Because the hydrogen bond formed between donor (D) and acceptor (A) is cooperatively strengthened or weakened by a newly formed hydrogen bond at D or A, we have proposed the following notation for hydrogen-bonding patterns of monohydric alcohols: a(D)DAd(A)a(A), where a is the number of protons accepted by D (a(D)) or A (a(A)), and d(A) is the number of protons donated by A. The indicator of the hydrogen-bond strength, which is given by M(OH) = a(D) + d(A) - a(A), is correlated well with the nu(OH) wavenumber of the methanol molecule D participating in the a(D)DAd(A)a(A) pattern. The correlation between M(OH) and the hydrogen-bonding energy of the a(D)DAd(A)a(A) pattern has also been deduced from the calculation results for the clusters. The nu(OH) bands of methanol measured in the CCl4 solution and pure liquid have been successfully analyzed by the method proposed here. PMID:18636720

  19. Organ Donor FAQ's: Who Can Be a Donor

    MedlinePlus

    ... citizens have been organ donors. Can non-resident aliens donate and receive organs? Non-resident aliens can both donate and receive organs in the ... the 12,375 organ donors were non-resident aliens. In this same year, 259 (1%) of the ...

  20. Polarised black holes in AdS

    NASA Astrophysics Data System (ADS)

    Costa, Miguel S.; Greenspan, Lauren; Oliveira, Miguel; Penedones, João; Santos, Jorge E.

    2016-06-01

    We consider solutions in Einstein-Maxwell theory with a negative cosmological constant that asymptote to global AdS 4 with conformal boundary {S}2× {{{R}}}t. At the sphere at infinity we turn on a space-dependent electrostatic potential, which does not destroy the asymptotic AdS behaviour. For simplicity we focus on the case of a dipolar electrostatic potential. We find two new geometries: (i) an AdS soliton that includes the full backreaction of the electric field on the AdS geometry; (ii) a polarised neutral black hole that is deformed by the electric field, accumulating opposite charges in each hemisphere. For both geometries we study boundary data such as the charge density and the stress tensor. For the black hole we also study the horizon charge density and area, and further verify a Smarr formula. Then we consider this system at finite temperature and compute the Gibbs free energy for both AdS soliton and black hole phases. The corresponding phase diagram generalizes the Hawking-Page phase transition. The AdS soliton dominates the low temperature phase and the black hole the high temperature phase, with a critical temperature that decreases as the external electric field increases. Finally, we consider the simple case of a free charged scalar field on {S}2× {{{R}}}t with conformal coupling. For a field in the SU(N ) adjoint representation we compare the phase diagram with the above gravitational system.

  1. Quantum Computing in Silicon with Donor Electron Spins

    NASA Astrophysics Data System (ADS)

    Simmons, Michelle

    2014-03-01

    Extremely long electron and nuclear spin coherence times have recently been demonstrated in isotopically pure Si-28 making silicon one of the most promising semiconductor materials for spin based quantum information. The two level spin state of single electrons bound to shallow phosphorus donors in silicon in particular provide well defined, reproducible qubits and represent a promising system for a scalable quantum computer in silicon. An important challenge in these systems is the realisation of an architecture, where we can position donors within a crystalline environment with approx. 20-50nm separation, individually address each donor, manipulate the electron spins using ESR techniques and read-out their spin states. We have developed a unique fabrication strategy for a scalable quantum computer in silicon using scanning tunneling microscope hydrogen lithography to precisely position individual P donors in a Si crystal aligned with nanoscale precision to local control gates necessary to initialize, manipulate, and read-out the spin states. During this talk I will focus on demonstrating electronic transport characteristics and single-shot spin read-out of precisely-positioned P donors in Si. Additionally I will report on our recent progress in performing single spin rotations by locally applying oscillating magnetic fields and initial characterization of transport devices with two and three single donors. The challenges of scaling up to practical 2D architectures will also be discussed.

  2. Dynamics of Homology Searching During Gene Conversion in Saccharomyces cerevisiae Revealed by Donor Competition

    PubMed Central

    Coïc, Eric; Martin, Joshua; Ryu, Taehyun; Tay, Sue Yen; Kondev, Jané; Haber, James E.

    2011-01-01

    One of the least understood aspects of homologous recombination is the process by which the ends of a double-strand break (DSB) search the entire genome for homologous templates that can be used to repair the break. We took advantage of the natural competition between the alternative donors HML and HMR employed during HO endonuclease-induced switching of the budding yeast MAT locus. The strong mating-type-dependent bias in the choice of the donors is enforced by the recombination enhancer (RE), which lies 17 kb proximal to HML. We investigated factors that improve the use of the disfavored donor. We show that the normal heterochromatic state of the donors does not impair donor usage, as donor choice is not affected by removing this epigenetic silencing. In contrast, increasing the length of homology shared by the disfavored donor increases its use. This result shows that donor choice is not irrevocable and implies that there are several encounters between the DSB ends and even the favored donor before recombination is accomplished. The increase by adding more homology is not linear; these results can be explained by a thermodynamic model that determines the energy cost of using one donor over the other. An important inference from this analysis is that when HML is favored as the donor, RE causes a reduction in its effective genomic distance from MAT from 200 kb to ∼20 kb, which we hypothesize occurs after the DSB is created, by epigenetic chromatin modifications around MAT. PMID:21954161

  3. Donor Preferences and Charitable Giving

    ERIC Educational Resources Information Center

    Williams, Stephanie Roderick

    2007-01-01

    This study aimed to learn more of the differences that may exist between the two most powerful groups of donors today, baby boomers (40-58 years old) and mature donors (59 and older), in an effort to help organizations improve fundraising efforts. Questions about the importance of organizational efficiency, program outcomes, and the desire for…

  4. AP39, a novel mitochondria-targeted hydrogen sulfide donor, stimulates cellular bioenergetics, exerts cytoprotective effects and protects against the loss of mitochondrial DNA integrity in oxidatively stressed endothelial cells in vitro.

    PubMed

    Szczesny, Bartosz; Módis, Katalin; Yanagi, Kazunori; Coletta, Ciro; Le Trionnaire, Sophie; Perry, Alexis; Wood, Mark E; Whiteman, Matthew; Szabo, Csaba

    2014-09-15

    The purpose of the current study was to investigate the effect of the recently synthesized mitochondrially-targeted H2S donor, AP39 [(10-oxo-10-(4-(3-thioxo-3H-1,2-dithiol-5yl)phenoxy)decyl) triphenylphosphonium bromide], on bioenergetics, viability, and mitochondrial DNA integrity in bEnd.3 murine microvascular endothelial cells in vitro, under normal conditions, and during oxidative stress. Intracellular H2S was assessed by the fluorescent dye 7-azido-4-methylcoumarin. For the measurement of bioenergetic function, the XF24 Extracellular Flux Analyzer was used. Cell viability was estimated by the combination of the MTT and LDH methods. Oxidative protein modifications were measured by the Oxyblot method. Reactive oxygen species production was monitored by the MitoSOX method. Mitochondrial and nuclear DNA integrity were assayed by the Long Amplicon PCR method. Oxidative stress was induced by addition of glucose oxidase. Addition of AP39 (30-300 nM) to bEnd.3 cells increased intracellular H2S levels, with a preferential response in the mitochondrial regions. AP39 exerted a concentration-dependent effect on mitochondrial activity, which consisted of a stimulation of mitochondrial electron transport and cellular bioenergetic function at lower concentrations (30-100 nM) and an inhibitory effect at the higher concentration of 300 nM. Under oxidative stress conditions induced by glucose oxidase, an increase in oxidative protein modification and an enhancement in MitoSOX oxidation was noted, coupled with an inhibition of cellular bioenergetic function and a reduction in cell viability. AP39 pretreatment attenuated these responses. Glucose oxidase induced a preferential damage to the mitochondrial DNA; AP39 (100 nM) pretreatment protected against it. In conclusion, the current paper documents antioxidant and cytoprotective effects of AP39 under oxidative stress conditions, including a protection against oxidative mitochondrial DNA damage. PMID:24755204

  5. The Lombardy Rare Donor Programme

    PubMed Central

    Revelli, Nicoletta; Villa, Maria Antonietta; Paccapelo, Cinzia; Manera, Maria Cristina; Rebulla, Paolo; Migliaccio, Anna Rita; Marconi, Maurizio

    2014-01-01

    Background In 2005, the government of Lombardy, an Italian region with an ethnically varied population of approximately 9.8 million inhabitants including 250,000 blood donors, founded the Lombardy Rare Donor Programme, a regional network of 15 blood transfusion departments coordinated by the Immunohaematology Reference Laboratory of the Ca’ Granda Ospedale Maggiore Policlinico in Milan. During 2005 to 2012, Lombardy funded LORD-P with 14.1 million euros. Materials and methods During 2005–2012 the Lombardy Rare Donor Programme members developed a registry of blood donors and a bank of red blood cell units with either rare blood group phenotypes or IgA deficiency. To do this, the Immunohaematology Reference Laboratory performed extensive serological and molecular red blood cell typing in 59,738 group O or A, Rh CCDee, ccdee, ccDEE, ccDee, K− or k− donors aged 18–55 with a record of two or more blood donations, including both Caucasians and ethnic minorities. In parallel, the Immunohaematology Reference Laboratory implemented a 24/7 service of consultation, testing and distribution of rare units for anticipated or emergent transfusion needs in patients developing complex red blood cell alloimmunisation and lacking local compatible red blood cell or showing IgA deficiency. Results Red blood cell typing identified 8,747, 538 and 33 donors rare for a combination of common antigens, negative for high-frequency antigens and with a rare Rh phenotype, respectively. In June 2012, the Lombardy Rare Donor Programme frozen inventory included 1,157 red blood cell units. From March 2010 to June 2012 one IgA-deficient donor was detected among 1,941 screened donors and IgA deficiency was confirmed in four previously identified donors. From 2005 to June 2012, the Immunohaematology Reference Laboratory provided 281 complex red blood cell alloimmunisation consultations and distributed 8,008 Lombardy Rare Donor Programme red blood cell units within and outside the region

  6. Electrochemical activation of a tetrathiafulvalene halogen bond donor in solution.

    PubMed

    Oliveira, R; Groni, S; Fave, C; Branca, M; Mavré, F; Lorcy, D; Fourmigué, M; Schöllhorn, B

    2016-06-21

    The halogen bond donor properties of iodo-tetrathiafulvalene (I-TTF) can be electrochemically switched and controlled via reversible oxidation in the solution phase. Interestingly the activation of only one single halogen bond yielded already a strong and selective interaction, quantified by cyclic voltammetry. The standard potentials of the redox couples I-TTF(0/1+) and I-TTF(1+/2+) were observed to shift upon the addition of halides. These anions selectively stabilize the cationic I-TTF species through halogen bonding in polar liquid electrolytes. The thermodynamic affinity constants for chloride and bromide binding to the oxidized species have been determined. Competition in halide binding between I-TTF(1+) and other halogen bond donors allowed for comparing the relative donor strength of the respective electrophilic species. Furthermore it has been shown that halogen bonding can prevail over hydrogen bonding in the investigated system. PMID:27231819

  7. Successful use of the "unacceptable" heart donor.

    PubMed

    Menkis, A H; Novick, R J; Kostuk, W J; Pflugfelder, P W; Powell, A M; Thomson, D; McKenzie, F N

    1991-01-01

    Chronic shortage of donor organs has heightened interest in new strategies for increasing donor availability. Unacceptable hearts for transplant have previously been characterized by donor age greater than 40 years, more than 20% donor/recipient weight mismatch, ischemic time more than 4 hours, and the presence of coronary artery disease. A series of 185 consecutive orthotopic heart transplants were retrospectively examined. A significant number of donor hearts used were unacceptable by one or more of the above criteria. Our current approach is to match donors to recipients using a wide range of criteria. Donors are now accepted from any location in North America. We have accepted donors more than 55 years of age and donors weighing less than 50% of the recipient's body weight. Because of the chronic shortage of donor organs, donor criteria have been effectively liberalized, thereby increasing the donor pool without compromising the overall results of heart transplantation. PMID:2007168

  8. Two-stage coal liquefaction without gas-phase hydrogen

    DOEpatents

    Stephens, H.P.

    1986-06-05

    A process is provided for the production of a hydrogen-donor solvent useful in the liquefaction of coal, wherein the water-gas shift reaction is used to produce hydrogen while simultaneously hydrogenating a donor solvent. A process for the liquefaction of coal using said solvent is also provided. The process enables avoiding the use of a separate water-gas shift reactor as well as high pressure equipment for liquefaction. 3 tabs.

  9. One-step versus stepwise mechanism in protonated amino acid-promoted electron-transfer reduction of a quinone by electron donors and two-electron reduction by a dihydronicotinamide adenine dinucleotide analogue. Interplay between electron transfer and hydrogen bonding.

    PubMed

    Yuasa, Junpei; Yamada, Shunsuke; Fukuzumi, Shunichi

    2008-04-30

    Semiquinone radical anion of 1-(p-tolylsulfinyl)-2,5-benzoquinone (TolSQ(*-)) forms a strong hydrogen bond with protonated histidine (TolSQ(*-)/His x 2 H(+)), which was successfully detected by electron spin resonance. Strong hydrogen bonding between TolSQ(*-) and His x 2 H(+) results in acceleration of electron transfer (ET) from ferrocenes [R2Fc, R = C5H5, C5H4(n-Bu), C5H4Me] to TolSQ, when the one-electron reduction potential of TolSQ is largely shifted to the positive direction in the presence of His x 2 H(+). The rates of His x 2 H(+)-promoted ET from R2Fc to TolSQ exhibit deuterium kinetic isotope effects due to partial dissociation of the N-H bond in His x 2 H(+) at the transition state, when His x 2 H(+) is replaced by the deuterated compound (His x 2 D(+)-d6). The observed deuterium kinetic isotope effect (kH/kD) decreases continuously with increasing the driving force of ET to approach kH/kD = 1.0. On the other hand, His x 2 H(+) also promotes a hydride reduction of TolSQ by an NADH analogue, 9,10-dihydro-10-methylacridine (AcrH2). The hydride reduction proceeds via the one-step hydride-transfer pathway. In such a case, a large deuterium kinetic isotope effect is observed in the rate of the hydride transfer, when AcrH2 is replaced by the dideuterated compound (AcrD2). In sharp contrast to this, no deuterium kinetic isotope effect is observed, when His x 2 H(+) is replaced by His x 2 D(+)-d6. On the other hand, direct protonation of TolSQ and 9,10-phenanthrenequinone (PQ) also results in efficient reductions of TolSQH(+) and PQH(+) by AcrH2, respectively. In this case, however, the hydride-transfer reactions occur via the ET pathway, that is, ET from AcrH2 to TolSQH(+) and PQH(+) occurs in preference to direct hydride transfer from AcrH2 to TolSQH(+) and PQH(+), respectively. The AcrH2(*+) produced by the ET oxidation of AcrH2 by TolSQH(+) and PQH(+) was directly detected by using a stopped-flow technique. PMID:18386924

  10. Adult living donor liver imaging

    PubMed Central

    Cai, Larry; Yeh, Benjamin M.; Westphalen, Antonio C.; Roberts, John P.; Wang, Zhen J.

    2016-01-01

    Adult living donor liver transplantation (LDLT) is increasingly used for the treatment of end-stage liver disease. The three most commonly harvested grafts for LDLT are left lateral segment, left lobe, and right lobe grafts. The left lateral segment graft, which includes Couinaud’s segments II and III, is usually used for pediatric recipients or small size recipients. Most of the adult recipients need either a left or a right lobe graft. Whether a left or right lobe graft should be harvested from the donors depends on estimated graft and donor remnant liver volume, as well as biliary and vascular anatomy. Detailed preoperative assessment of the potential donor liver volumetrics, biliary and vascular anatomy, and liver parenchyma is vital to minimize risks to the donors and maximize benefits to the recipients. Computed tomography (CT) and magnetic resonance imaging (MRI) are currently the imaging modalities of choice in the preoperative evaluation of potential donors. This review provides an overview of key surgical considerations in LDLT that the radiologists must be aware of, and imaging findings on CT and MRI that the radiologists must convey to the surgeons when evaluating potential donors for LDLT. PMID:26912106

  11. Adult living donor liver imaging.

    PubMed

    Cai, Larry; Yeh, Benjamin M; Westphalen, Antonio C; Roberts, John P; Wang, Zhen J

    2016-01-01

    Adult living donor liver transplantation (LDLT) is increasingly used for the treatment of end-stage liver disease. The three most commonly harvested grafts for LDLT are left lateral segment, left lobe, and right lobe grafts. The left lateral segment graft, which includes Couinaud's segments II and III, is usually used for pediatric recipients or small size recipients. Most of the adult recipients need either a left or a right lobe graft. Whether a left or right lobe graft should be harvested from the donors depends on estimated graft and donor remnant liver volume, as well as biliary and vascular anatomy. Detailed preoperative assessment of the potential donor liver volumetrics, biliary and vascular anatomy, and liver parenchyma is vital to minimize risks to the donors and maximize benefits to the recipients. Computed tomography (CT) and magnetic resonance imaging (MRI) are currently the imaging modalities of choice in the preoperative evaluation of potential donors. This review provides an overview of key surgical considerations in LDLT that the radiologists must be aware of, and imaging findings on CT and MRI that the radiologists must convey to the surgeons when evaluating potential donors for LDLT. PMID:26912106

  12. Living kidney donors and ESRD.

    PubMed

    Ross, Lainie Friedman

    2015-07-01

    There are more than 325 living kidney donors who have developed end-stage renal disease and have been listed on the Organ Procurement and Transplantation Network (OPTN)/United Network for Organ Sharing (UNOS) deceased donor kidney wait list. The OPTN/UNOS database records where these kidney donors are listed and, if they donated after April 1994, where that donation occurred. These 2 locations are often not the same. In this commentary, I examine whether a national living donor registry should be created and whether transplantation centers should be notified when one of their living kidney donors develops end-stage renal disease. I consider and refute 5 potential objections to center notification. I explain that transplantation centers should look back at these cases and input data into a registry to attempt to identify patterns that could improve donor evaluation protocols. Creating a registry and mining the information it contains is, in my view, our moral and professional responsibility to future patients and the transplantation endeavor. As individuals and as a community, we need to acknowledge the many unknown risks of living kidney donation and take responsibility for identifying these risks. We then must share information about these risks, educate prospective donors about them, and attempt to minimize them. PMID:25936672

  13. Production of dimethylfuran from hydroxymethylfurfural through catalytic transfer hydrogenation with ruthenium supported on carbon.

    PubMed

    Jae, Jungho; Zheng, Weiqing; Lobo, Raul F; Vlachos, Dionisios G

    2013-07-01

    RuC ees' transfer: Transfer hydrogenation using alcohols as hydrogen donors and supported ruthenium catalysts results in the selective conversion of hydroxymethylfurfural to dimethylfuran (>80% yield). During transfer hydrogenation, the hydrogen produced from alcohols is utilized in the hydrogenation of hydroxymethylfurfural. PMID:23754805

  14. Electron donor preference of a reductive dechlorinating consortium

    USGS Publications Warehouse

    Lorah, M.M.; Majcher, E.; Jones, E.; Driedger, G.; Dworatzek, S.; Graves, D.

    2005-01-01

    A wetland sediment-derived microbial consortium was developed by the USGS and propagated in vitro to large quantities by SiREM Laboratory for use in bioaugmentation applications. The consortium had the capacity to completely dechlorinate 1,1,2,2-tetrachloroethene, tetrachloroethylene, trichloroethylene, 1,1,2-trichloroethane, cis- and trans-1,2-dichoroethylene, 1.1-dichloroethylene, 1,2-dichloroethane, vinyl chloride, carbon tetrachloride and chloroform. A suite of electron donors with characteristics useful for bioaugmentation applications was tested. The electron donors included lactate (the donor used during WBC-2 development), ethanol, chitin (Chitorem???), hydrogen releasing compound (HRC???), emulsified vegetable oil (Newman Zone???), and hydrogen gas. Ethanol, lactate, and chitin were particularly effective with respect to stimulating, supporting, and sustaining reductive dechlorination of the broad suite of chemicals that WBC-2 biodegraded. Chitorem??? was the most effective "slow release" electron donor tested. This is an abstract of a paper presented at the Proceedings of the 8th International In Situ and On-Site Bioremediation Symposium (Baltimore, MD 6/6-9/2005).

  15. How to Motivate Whole Blood Donors to Become Plasma Donors

    PubMed Central

    2014-01-01

    This study tested the efficacy of interventions to recruit new plasma donors among whole blood donors. A sample of 924 donors was randomized to one of three conditions: control; information only by nurse; and information plus self-positive image message by nurse (SPI). Participants in the control condition only received a leaflet describing the plasma donation procedure. In the two experimental conditions the leaflet was explained face-to-face by a nurse. The dependent variables were the proportion of new plasma donors and the number of donations at six months. Overall, 141 (15.3%) new plasma donors were recruited at six months. There were higher proportions of new plasma donors in the two experimental conditions compared to the control condition (P < .001); the two experimental conditions did not differ. Also, compared to the control condition, those in the experimental conditions (all Ps < .001) gave plasma more often (information only by nurse:  d = .26; SPI: d = .32); the SPI intervention significantly outperformed (P < .05) the information only by nurse condition. The results suggest that references to feelings of SPI such as feeling good and being proud and that giving plasma is a rewarding personal experience favor a higher frequency of plasma donation. PMID:25530909

  16. Smeared antibranes polarise in AdS

    NASA Astrophysics Data System (ADS)

    Gautason, Fridrik Freyr; Truijen, Brecht; Van Riet, Thomas

    2015-07-01

    In the recent literature it has been questioned whether the local backreaction of antibranes in flux throats can induce a perturbative brane-flux decay. Most evidence for this can be gathered for D6 branes and D p branes smeared over 6 - p compact directions, in line with the absence of finite temperature solutions for these cases. The solutions in the literature have flat worldvolume geometries and non-compact transversal spaces. In this paper we consider what happens when the worldvolume is AdS and the transversal space is compact. We show that in these circumstances brane polarisation smoothens out the flux singularity, which is an indication that brane-flux decay is prevented. This is consistent with the fact that the cosmological constant would be less negative after brane-flux decay. Our results extend recent results on AdS7 solutions from D6 branes to AdS p+1 solutions from D p branes. We show that supersymmetry of the AdS solutions depend on p non-trivially.

  17. Quantum confined acceptors and donors in InSe nanosheets

    SciTech Connect

    Mudd, G. W.; Patanè, A. Makarovsky, O.; Eaves, L.; Kudrynskyi, Z. R.; Kovalyuk, Z. D.; Fay, M. W.; Zólyomi, V.; Falko, V.

    2014-12-01

    We report on the radiative recombination of photo-excited carriers bound at native donors and acceptors in exfoliated nanoflakes of nominally undoped rhombohedral γ-polytype InSe. The binding energies of these states are found to increase with the decrease in flake thickness, L. We model their dependence on L using a two-dimensional hydrogenic model for impurities and show that they are strongly sensitive to the position of the impurities within the nanolayer.

  18. AdS orbifolds and Penrose limits

    SciTech Connect

    Alishahiha, Mohsen; Sheikh-Jabbari, Mohammad M.; Tatar, Radu

    2002-12-09

    In this paper we study the Penrose limit of AdS{sub 5} orbifolds. The orbifold can be either in the pure spatial directions or space and time directions. For the AdS{sub 5}/{Lambda} x S{sup 5} spatial orbifold we observe that after the Penrose limit we obtain the same result as the Penrose limit of AdS{sub 5} x S{sup 5}/{Lambda}. We identify the corresponding BMN operators in terms of operators of the gauge theory on R x S{sup 3}/{Lambda}. The semi-classical description of rotating strings in these backgrounds have also been studied. For the spatial AdS orbifold we show that in the quadratic order the obtained action for the fluctuations is the same as that in S{sup 5} orbifold, however, the higher loop correction can distinguish between two cases.

  19. Donor states in inverse opals

    NASA Astrophysics Data System (ADS)

    Mahan, G. D.

    2014-09-01

    We calculate the binding energy of an electron bound to a donor in a semiconductor inverse opal. Inverse opals have two kinds of cavities, which we call octahedral and tetrahedral, according to their group symmetry. We put the donor in the center of each of these two cavities and obtain the binding energy. The binding energies become very large when the inverse opal is made from templates with small spheres. For spheres less than 50 nm in diameter, the donor binding can increase to several times its unconfined value. Then electrons become tightly bound to the donor and are unlikely to be thermally activated to the semiconductor conduction band. This conclusion suggests that inverse opals will be poor conductors.

  20. Donor states in inverse opals

    SciTech Connect

    Mahan, G. D.

    2014-09-21

    We calculate the binding energy of an electron bound to a donor in a semiconductor inverse opal. Inverse opals have two kinds of cavities, which we call octahedral and tetrahedral, according to their group symmetry. We put the donor in the center of each of these two cavities and obtain the binding energy. The binding energies become very large when the inverse opal is made from templates with small spheres. For spheres less than 50 nm in diameter, the donor binding can increase to several times its unconfined value. Then electrons become tightly bound to the donor and are unlikely to be thermally activated to the semiconductor conduction band. This conclusion suggests that inverse opals will be poor conductors.

  1. Being a Living Donor: Risks

    MedlinePlus

    ... for blood transfusions side effects associated with allergic reactions to the anesthesia death The best source of information about risks and expected donor outcomes is your transplant team. In addition, it’s important to take an active role in ...

  2. A model of willingness to become a potential organ donor.

    PubMed

    Horton, R L; Horton, P J

    1991-01-01

    This article presents two models of the decision to become a potential organ donor. In the first model the act of carrying or requesting an organ donor card is related to values and factual knowledge regarding organ donation, through intervening attitude and willingness constructs. A sample of 286 students is used to test this model via the LISREL computer program for modeling latent variables. All hypothesized relationships had the predicted sign and were significant. This model is extended by adding the variables attitude towards death, prior blood donation, and age of subject to the model. A second sample of 365 adults from the local community is used to test the second model via LISREL. With two exceptions in the adult sample, all hypothesized relationships had the predicted sign and were significant. Where the two models overlap the results are generally similar. Implications of the models for marketing the act of becoming a potential organ donor are discussed. PMID:1771431

  3. Motivations for Giving of Alumni Donors, Lapsed Donors and Non-Donors: Implications for Christian Higher Education

    ERIC Educational Resources Information Center

    Rugano, Emilio Kariuki

    2011-01-01

    This descriptive and causal comparative study sought to identify motivations for alumni donor acquisition and retention in Christian institutions of higher learning. To meet this objective, motivations for alumni donors, lapsed donors, and non-donors were analyzed and compared. Data was collected through an electronic survey of a stratified sample…

  4. [Non-heart-beating donors are ineligible].

    PubMed

    Heide, W

    2016-02-01

    The death of the donor is a mandatory prerequisite for organ transplantation (dead donor rule) worldwide. It is a medical, legal and ethical consensus to accept the concept of brain death, as first proposed in 1968 by the ad hoc committee of the Harvard Medical School, as a certain criterion of death. In isolated cases where the diagnosis of brain death was claimed to be wrong, it could be demonstrated that the diagnostic procedure for brain death had not been correctly performed. In March 2014 a joint statement by the German neuromedical societies emphasized that 1) the diagnosis of brain death is one of the safest diagnoses in medicine if performed according to accepted medical standards and criteria and 2) the concept of non-heart-beating donors (NHBD, i. e. organ donation after an arbitrarily defined duration of circulatory and cardiac arrest) practiced in some European countries must be absolutely rejected because it implicates a high risk of diagnostic error. According to the current literature it is unclear at what time cardiac and circulatory arrest is irreversible and leads to irreversible cessation of all functions of the entire brain including the brainstem, even though clinical signs of cessation of brain functions are always found after 10 min. Furthermore, is it often an arbitrary decision to exactly define the duration of cardiac arrest if continuous echocardiographic monitoring has not been carried out from the very beginning. Last but not least there are ethical concerns against the concept of NHBD because it might influence therapeutic efforts to resuscitate a patient with cardiac arrest. Therefore, the German Medical Council (BÄK) has repeatedly rejected the concept of NHBD for organ transplantation since 1995. PMID:26830897

  5. Analysis of Donor Motivations in Living Donor Liver Transplantation

    PubMed Central

    Abdeldayem, Hesham; Kashkoush, Samy; Hegab, Bassem Soliman; Aziz, Amr; Shoreem, Hany; Saleh, Shereef

    2014-01-01

    Objectives: The introduction of the living donor liver transplantation (LDLT) in Egypt as in elsewhere, has raised important psychological conflicts and ethical questions. The objective of this study was to get better understanding of the potential donors’ motives toward LDLT. Methods: This study was conducted on consecutive 193 living-liver donors who underwent partial hepatectomy as donors for LDLT during the period between April 2003 and January 2013, at the National Liver Institute Menoufeyia University, Egypt. Potential donors were thoroughly evaluated preoperatively through a screening questionnaire and interviews as regard their demographic data, relationship to the potential recipient, and motives toward proceeding to surgery. They were assured that the information shared between them and the transplant center is confidential. Results: The donors’ mean age was 25.53 ± 6.39 years with a range of 18–45 years. Males represented 64.7% and females were 35.3%. The most common donors (32.1%, n = 62) were sons and daughters to their parents (sons: n = 43, daughters: n = 19) while parents to their offsprings represent 15% (mothers: n = 21, fathers: n = 8). Brothers and sisters represent 16.5% (brothers: n = 22, sisters: n = 10). Nephews and nieces giving their uncles or aunts were 14%. The number of wives donating to their husbands was 11 (5.7%). Interestingly, there was no single husband who donated his wife. Among the remaining donors, there were 11 cousins and 1 uncle. Unrelated donors were 20 (10.4%). Several factors seemed to contribute to motivation for donation: the seriousness of the potential recipient condition, the relationship and personal history of the donor to the potential recipient, the religious beliefs, the trust in the health care system, and family dynamics and obligations. Conclusion: Absolute absence of coercion on the living-liver donor’s motives may not be realistic because of the serious

  6. Blood Donation by Elderly Repeat Blood Donors

    PubMed Central

    Zeiler, Thomas; Lander-Kox, Jutta; Alt, Timo

    2014-01-01

    Summary Background Upper age limits for blood donors are intended to protect elderly blood donors from donor reactions. However, due to a lack of data about adverse reactions in elderly blood donors, upper age limits are arbitrary and vary considerably between different countries. Methods Here we present data from 171,231 voluntary repeat whole blood donors beyond the age of 68 years. Results Blood donations from repeat blood donors beyond the age of 68 years increased from 2,114 in 2005 to 38,432 in 2012 (from 0,2% to 4.2% of all whole blood donations). Adverse donor reactions in repeat donors decreased with age and were lower than in the whole group (0.26%), even in donors older than 71 years (0.16%). However, from the age of 68 years, the time to complete recovery after donor reactions increased. Donor deferrals were highest in young blood donors (21.4%), but increased again in elderly blood donors beyond 71 years (12.6%). Conclusion Blood donation by regular repeat blood donors older than 71 years may be safely continued. However, due to a lack of data for donors older than 75 years, blood donation in these donors should be handled with great caution. PMID:25254019

  7. High-Affinity Proton Donors Promote Proton-Coupled Electron Transfer by Samarium Diiodide.

    PubMed

    Chciuk, Tesia V; Anderson, William R; Flowers, Robert A

    2016-05-10

    The relationship between proton-donor affinity for Sm(II) ions and the reduction of two substrates (anthracene and benzyl chloride) was examined. A combination of spectroscopic, thermochemical, and kinetic studies show that only those proton donors that coordinate or chelate strongly to Sm(II) promote anthracene reduction through a PCET process. These studies demonstrate that the combination of Sm(II) ions and water does not provide a unique reagent system for formal hydrogen atom transfer to substrates. PMID:27061351

  8. Hydrogen bonding tunes the early stage of hydrogen-atom abstracting reaction.

    PubMed

    Yang, Yang; Liu, Lei; Chen, Junsheng; Han, Keli

    2014-09-01

    The spontaneous and collision-assisted hydrogen-atom abstracting reaction (HA) dynamics of triplet benzil are investigated through the combination of transient absorption spectroscopy with TD-DFT calculations. HA dynamics exhibit a remarkable dependence on the hydrogen donor properties. The effects of the triplet-state hydrogen bonding on the reaction dynamics are illustrated. In particular, it is experimentally observed that strengthened triplet-state hydrogen bonding could accelerate the HA, whereas weakened triplet-state hydrogen bonding would postpone the HA. The triplet-state hydrogen bonding has great influences on the early stage of the HA reaction, while the bond dissociation energy of the hydrogen donors determines the subsequent reaction pathways. Protic solvents could sustain longer lifetimes of the excited-state intermediate formed after HA than non-protic solvents by 10 μs. This investigation provides insights into the HA dynamics and guidance to improve the product efficiency of photochemical reactions. PMID:25036436

  9. Donor Hemovigilance with Blood Donation

    PubMed Central

    Diekamp, Ulrich; Gneißl, Johannes; Rabe, Angela; Kießig, Stephan T.

    2015-01-01

    Background Reports on unexpected events (UEs) during blood donation (BD) inadequately consider the role of technical UEs. Methods Defined local and systemic UEs were graded by severity; technical UEs were not graded. On January 1, 2008, E.B.P.S.-Logistics (EBPS) installed the UE module for plasma management software (PMS). Donor room physicians entered UEs daily into PMS. Medical directors reviewed entries quarterly. EBPS compiled data on donors, donations, and UEs from January 1, 2008 to June 30, 2011. Results 6,605 UEs were observed during 166,650 BDs from 57,622 donors for a corrected incidence of 4.30% (0.66% local, 1.59% systemic, 2.04% technical UEs). 2.96% of BDs were accompanied by one UE and 0.45% by >1 UE (2-4). 6.3% of donors donating blood for their first time, 3.5% of those giving blood for their second time, and 1.9% of donors giving their third or more BD experienced UEs. Most common UEs were: discontinued collections due to venous access problems, repeated venipuncture, and small hematomas. Severe circulatory UEs occurred at a rate of 16 per 100,000 BDs. Conclusions Technical UEs were common during BD. UEs accompanied first and second donations significantly more often than subsequent donations. PMID:26195932

  10. Hydrogen production

    NASA Technical Reports Server (NTRS)

    England, C.; Chirivella, J. E.; Fujita, T.; Jeffe, R. E.; Lawson, D.; Manvi, R.

    1975-01-01

    The state of hydrogen production technology is evaluated. Specific areas discussed include: hydrogen production fossil fuels; coal gasification processes; electrolysis of water; thermochemical production of hydrogen; production of hydrogen by solar energy; and biological production of hydrogen. Supply options are considered along with costs of hydrogen production.

  11. [Living donor transplantation. Surgical complications].

    PubMed

    Karam, Georges

    2008-02-01

    Although nephrectomy by open surgery is the most used technique for the extraction of kidney transplants in the living donor, nephrectomy under laparaoscopy is increasingly practiced. Laparoscopic nephrectomy is less invasive and performed under videoscopy control, after insufflation of the peritoneal cavity. Three to four incisions are done in order to enter the surgical instruments. The kidney is extracted through a horizontal sus-pubic incision. The exposition is either exclusively transperitoneal, retroperitoneal or hand assisted. The advantages of laparoscopy are esthetical, financial due to a shorter hospitalisation and a quicker recovery, as well a confort for the donor. The disadvantages are a longer warm ischemia time and possibly a higher risk of delayed graft function. Randomised studies having compared laparoscopy and open surgery in the living donor have not find any significant difference regarding the per- and perioperative in the complications. PMID:18160357

  12. The AdS particle [rapid communication

    NASA Astrophysics Data System (ADS)

    Ghosh, Subir

    2005-09-01

    In this Letter we have considered a relativistic Nambu-Goto model for a particle in AdS metric. With appropriate gauge choice to fix the reparameterization invariance, we recover the previously discussed [S. Ghosh, P. Pal, Phys. Lett. B 618 (2005) 243, arxiv:hep-th/0502192] "exotic oscillator". The Snyder algebra and subsequently the κ-Minkowski spacetime are also derived. Lastly we comment on the impossibility of constructing a non-commutative spacetime in the context of open string where only a curved target space is introduced.

  13. Utilization of Deceased Donor Kidneys to Initiate Living Donor Chains.

    PubMed

    Melcher, M L; Roberts, J P; Leichtman, A B; Roth, A E; Rees, M A

    2016-05-01

    We propose that some deceased donor (DD) kidneys be allocated to initiate nonsimultaneous extended altruistic donor chains of living donor (LD) kidney transplants to address, in part, the huge disparity between patients on the DD kidney waitlist and available donors. The use of DD kidneys for this purpose would benefit waitlisted candidates in that most patients enrolled in kidney paired donation (KPD) systems are also waitlisted for a DD kidney transplant, and receiving a kidney through the mechanism of KPD will decrease pressure on the DD pool. In addition, a LD kidney usually provides survival potential equal or superior to that of DD kidneys. If KPD chains that are initiated by a DD can end in a donation of an LD kidney to a candidate on the DD waitlist, the quality of the kidney allocated to a waitlisted patient is likely to be improved. We hypothesize that a pilot program would show a positive impact on patients of all ethnicities and blood types. PMID:26833680

  14. The role of electron donors generated from UV photolysis for accelerating pyridine biodegradation.

    PubMed

    Tang, Yingxia; Zhang, Yongming; Yan, Ning; Liu, Rui; Rittmann, Bruce E

    2015-09-01

    Employing an internal circulation baffled biofilm reactor (ICBBR), we evaluated the mechanisms by which photolysis accelerated the biodegradation and mineralization of pyridine (C5 H5 N), a nitrogen-containing heterocyclic compound. We tested the hypothesis that pyridine oxidation is accelerated because a key photolysis intermediate, succinate, is as electron donor that promotes the initial mono-oxygenation of pyridine. Experimentally, longer photolysis time generated more electron-donor products (succinate), which stimulated faster pyridine biodegradation. This pattern was confirmed by directly adding succinate, and the stimulation effect occurred similarly with addition of the same equivalents of acetate and formate. Succinate, whether generated by UV photolysis or added directly, also accelerated mono-oxygenation of the first biodegradation intermediate, 2-hydroxyl pyridine (2HP). 2HP and pyridine were mutually inhibitory in that their mono-oxygenations competed for internal electron donor; thus, the addition of any readily biodegradable donor accelerated both mono-oxygenation steps, as well as mineralization. PMID:25854706

  15. Probing crunching AdS cosmologies

    NASA Astrophysics Data System (ADS)

    Kumar, S. Prem; Vaganov, Vladislav

    2016-02-01

    Holographic gravity duals of deformations of CFTs formulated on de Sitter spacetime contain FRW geometries behind a horizon, with cosmological big crunch singularities. Using a specific analytically tractable solution within a particular single scalar truncation of {N}=8 supergravity on AdS4, we first probe such crunching cosmologies with spacelike radial geodesics that compute spatially antipodal correlators of large dimension boundary operators. At late times, the geodesics lie on the FRW slice of maximal expansion behind the horizon. The late time two-point functions factorise, and when transformed to the Einstein static universe, they exhibit a temporal non-analyticity determined by the maximal value of the scale factor ã max. Radial geodesics connecting antipodal points necessarily have de Sitter energy Ɛ ≲ ã max, while geodesics with Ɛ > ã max terminate at the crunch, the two categories of geodesics being separated by the maximal expansion slice. The spacelike crunch singularity is curved "outward" in the Penrose diagram for the deformed AdS backgrounds, and thus geodesic limits of the antipodal correlators do not directly probe the crunch. Beyond the geodesic limit, we point out that the scalar wave equation, analytically continued into the FRW patch, has a potential which is singular at the crunch along with complex WKB turning points in the vicinity of the FRW crunch. We then argue that the frequency space Green's function has a branch point determined by ã max which corresponds to the lowest quasinormal frequency.

  16. Documented deaths of hepatic lobe donors for living donor liver transplantation.

    PubMed

    Trotter, James F; Adam, Rene; Lo, Chung Mau; Kenison, Jeremy

    2006-10-01

    The actual risk of death in hepatic lobe donors for living donor liver transplantation (LDLT) is unknown because of the lack of a comprehensive database. In the absence of a definitive estimate of the risk of donor death, the medical literature has become replete with anecdotal reports of donor deaths, many of which cannot be substantiated. Because donor death is one of the most important outcomes of LDLT, we performed a comprehensive survey of the medical and lay literature to provide a referenced source of worldwide donor deaths. We reviewed all published articles from the medical literature on LDLT and searched the lay literature for donor deaths from 1989 to February 2006. We classified each death as "definitely," "possibly," or "unlikely" related to donor surgery. We identified 19 donor deaths (and one additional donor in a chronic vegetative state). Thirteen deaths and the vegetative donor were "definitely," 2 were "possibly," and 4 were "unlikely" related to donor surgery. The estimated rate of donor death "definitely" related to donor surgery is 0.15%. The rate of donor death which is "definitely" or "possibly" related to the donor surgery is 0.20%. This analysis provides a source document of all identifiable living liver donor deaths, provides a better estimate of donor death rate, and may provide an impetus for centers with unreported deaths to submit these outcomes to the liver transplantation community. PMID:16952175

  17. Single-Donor Leukophoretic Technique

    NASA Technical Reports Server (NTRS)

    Eberhardt, R. N.

    1977-01-01

    Leukocyte separation-and-retrieval device utilizes granulocyte and monocyte property of leukoadhesion to glass surfaces as basis of their separation from whole blood. Device is used with single donor technique and has application in biological and chemical processing, veterinary research and clinical care.

  18. Physician Migration: Donor Country Impact

    ERIC Educational Resources Information Center

    Aluwihare, A. P. R.

    2005-01-01

    Physician migration from the developing to developed region of a country or the world occurs for reasons of financial, social, and job satisfaction. It is an old phenomenon that produces many disadvantages for the donor region or nation. The difficulties include inequities with the provision of health services, financial loss, loss of educated…

  19. Photoinduced hydrogen-bonding dynamics.

    PubMed

    Chu, Tian-Shu; Xu, Jinmei

    2016-09-01

    Hydrogen bonding dynamics has received extensive research attention in recent years due to the significant advances in femtolaser spectroscopy experiments and quantum chemistry calculations. Usually, photoexcitation would cause changes in the hydrogen bonding formed through the interaction between hydrogen donor and acceptor molecules on their ground electronic states, and such transient strengthening or weakening of hydrogen bonding could be crucial for the photophysical transformations and the subsequent photochemical reactions that occurred on a time scale from tens of femtosecond to a few nanoseconds. In this article, we review the combined experimental and theoretical studies focusing on the ultrafast electronic and vibrational hydrogen bonding dynamics. Through these studies, new mechanisms and proposals and common rules have been put forward to advance our understanding of the hydrogen bondings dynamics in a variety of important photoinduced phenomena like photosynthesis, dual fluorescence emission, rotational reorientation, excited-state proton transfer and charge transfer processes, chemosensor fluorescence sensing, rearrangements of the hydrogen-bond network including forming and breaking hydrogen bond in water. Graphical Abstract We review the recent advances on exploring the photoinduced hydrogen bonding dynamics in solutions through a joint approach of laser spectroscopy and theoretical calculation. The reviewed studies have put forward a new mechanism, new proposal, and new rule for a variety of photoinduced phenomena such as photosynthesis, dual fluorescence emission, rotational reorientation, excited-state proton transfer and charge transfer, chemosensor fluorescence sensing, and rearrangements of the hydrogen-bond network in water. PMID:27491849

  20. Enantioselective Claisen rearrangements with a hydrogen-bond donor catalyst.

    PubMed

    Uyeda, Christopher; Jacobsen, Eric N

    2008-07-23

    N,N'-Diphenylguanidinium ion associated with the noncoordinating BArF counterion is shown to be an effective catalyst for the [3,3]-sigmatropic rearrangement of a variety of substituted allyl vinyl ethers. Highly enantioselective catalytic Claisen rearrangements of ester-substituted allyl vinyl ethers are then documented using a new C2-symmetric guanidinium ion derivative. PMID:18576616

  1. AdS3: the NHEK generation

    NASA Astrophysics Data System (ADS)

    Bena, Iosif; Heurtier, Lucien; Puhm, Andrea

    2016-05-01

    It was argued in [1] that the five-dimensional near-horizon extremal Kerr (NHEK) geometry can be embedded in String Theory as the infrared region of an infinite family of non-supersymmetric geometries that have D1, D5, momentum and KK monopole charges. We show that there exists a method to embed these geometries into asymptotically- {AdS}_3× {S}^3/{{Z}}_N solutions, and hence to obtain infinite families of flows whose infrared is NHEK. This indicates that the CFT dual to the NHEK geometry is the IR fixed point of a Renormalization Group flow from a known local UV CFT and opens the door to its explicit construction.

  2. Shadows, currents, and AdS fields

    SciTech Connect

    Metsaev, R. R.

    2008-11-15

    Conformal totally symmetric arbitrary spin currents and shadow fields in flat space-time of dimension greater than or equal to four are studied. A gauge invariant formulation for such currents and shadow fields is developed. Gauge symmetries are realized by involving the Stueckelberg fields. A realization of global conformal boost symmetries is obtained. Gauge invariant differential constraints for currents and shadow fields are obtained. AdS/CFT correspondence for currents and shadow fields and the respective normalizable and non-normalizable solutions of massless totally symmetric arbitrary spin AdS fields are studied. The bulk fields are considered in a modified de Donder gauge that leads to decoupled equations of motion. We demonstrate that leftover on shell gauge symmetries of bulk fields correspond to gauge symmetries of boundary currents and shadow fields, while the modified de Donder gauge conditions for bulk fields correspond to differential constraints for boundary conformal currents and shadow fields. Breaking conformal symmetries, we find interrelations between the gauge invariant formulation of the currents and shadow fields, and the gauge invariant formulation of massive fields.

  3. Enantioselective Intramolecular C-H Insertion of Donor and Donor/Donor Carbenes by a Nondiazo Approach.

    PubMed

    Zhu, Dong; Ma, Jun; Luo, Kui; Fu, Hongguang; Zhang, Li; Zhu, Shifa

    2016-07-11

    The first enantioselective intramolecular C-H insertion and cyclopropanation reactions of donor- and donor/donor-carbenes by a nondiazo approach are reported. The reactions were conducted in a one-pot manner without slow addition and provided the desired dihydroindole, dihydrobenzofuran, tetrahydrofuran, and tetrahydropyrrole derivatives with up to 99 % ee and 100 % atom efficiency. PMID:27265896

  4. Hydrogen-Atom Transfer Reactions.

    PubMed

    Wang, Liang; Xiao, Jian

    2016-04-01

    The cascade [1,n]-hydrogen transfer/cyclization, recognized as the tert-amino effect one century ago, has received considerable interest in recent decades, and great achievements have been made. With the aid of this strategy, the inert C(sp(3))-H bonds can be directly functionalized into C-C, C-N, C-O bonds under catalysis of Lewis acids, Brønsted acids, as well as organocatalysts, and even merely under thermal conditions. Hydrogen can be transferred intramolecularly from hydrogen donor to acceptor in the form of hydride, or proton, followed by cyclization to furnish the cyclic products in processes featuring high atom economy. Methylene/methine adjacent to heteroatoms, e.g., nitrogen, oxygen, sulfur, can be exploited as hydride donor as well as methylene/methine without heteroatom assistance. Miscellaneous electrophilic subunits or intermediates, e.g., alkylidene malonate, carbophilic metal activated alkyne or allene, α,β-unsaturated aldehydes/ketone, saturated aldehydes/iminium, ketenimine/carbodiimide, metal carbenoid, electron-withdrawing groups activated allene/alkyne, in situ generated carbocation, can serve as hydride acceptors. This methodology has shown preeminent power to construct 5-, 6-, or 7-membered heterocyclic as well as carbon rings. In this chapter, various hydrogen donors and acceptors are adequately discussed. PMID:27573142

  5. Kinetics of catalytic transfer hydrogenation of soybean lecithin

    SciTech Connect

    Naglic, M.; Smidovnik, A.; Koloini, T.

    1997-12-01

    Catalytic transfer hydrogenation of soybean lecithin has been studied using aqueous sodium formate solution as hydrogen donor and palladium on carbon as catalyst. Kinetic constants and selectivity have been determined at intensive stirring. Hydrogenation reactions followed the first-order kinetics with respect to fatty acids. In addition to short reaction time, this method offers safe and easy handling. Hydrogenated soybean lecithin provides products with increased stability with respect to oxidation.

  6. Carbon related donor bound exciton transitions in ZnO nanowires

    SciTech Connect

    Mohammadbeigi, F.; Kumar, E. Senthil; Alagha, S.; Anderson, I.; Watkins, S. P.

    2014-08-07

    Several shallow donor bound exciton photoluminescence (PL) transitions are reported in ZnO nanowires doped with carbon. The emission energies are in the range of 3360.8–3361.9 meV, close to previously reported emission lines due to excitons bound to donor point defects, such as Ga, Al, In, and H. The addition of small amounts of hydrogen during growth results in a strong enhancement of the PL of these carbon related emission lines, yet PL and annealing measurements indicate no appreciable bulk hydrogen. The observation of two electron satellites for these emission lines enables the determination of the donor binding energies. The dependence of exciton localization energy on donor binding energy departs somewhat from the usual linear relationship observed for group III donors, indicating a qualitatively different central cell potential, as one would expect for a complex. Emission lines due to excitons bound to ionized donors associated with these defects are also observed. The dependence of the PL emission intensities on temperature and growth conditions demonstrates that the lines are due to distinct complexes and not merely excited states of each other.

  7. 21 CFR 630.6 - Donor notification.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... GENERAL REQUIREMENTS FOR BLOOD, BLOOD COMPONENTS, AND BLOOD DERIVATIVES § 630.6 Donor notification. (a) Notification of donors. You, an establishment that collects blood or blood components, must make reasonable... of donation of blood or blood components that the donor should not donate in the future; (3)...

  8. Reduced hydrogen permeability at high temperatures

    NASA Technical Reports Server (NTRS)

    Stephens, J. R.; Klopp, W. D.; Misencik, J. A.

    1981-01-01

    CO and CO2 reduce hydrogen loss through iron, nickel, and cobalt based alloy tubes. Method is based on concept that oxide film on metal surface reduces hydrogen permeability through metal; adding CO or CO2 forms oxide films continuously during operation, and hydrogen containment is improved. Innovation enhances prospects for Stirling engine system utilization.

  9. Hydrogen sensor

    DOEpatents

    Duan, Yixiang; Jia, Quanxi; Cao, Wenqing

    2010-11-23

    A hydrogen sensor for detecting/quantitating hydrogen and hydrogen isotopes includes a sampling line and a microplasma generator that excites hydrogen from a gas sample and produces light emission from excited hydrogen. A power supply provides power to the microplasma generator, and a spectrometer generates an emission spectrum from the light emission. A programmable computer is adapted for determining whether or not the gas sample includes hydrogen, and for quantitating the amount of hydrogen and/or hydrogen isotopes are present in the gas sample.

  10. Hyperbilirubinemia in normal healthy donors

    PubMed Central

    Arora, Veena; Kulkarni, R. K.; Cherian, Susan; Pillai, Raji; Shivali, M.

    2009-01-01

    The present study was carried out in B.A.R.C. Hospital Blood Bank over a span of five years, and includes 2734 donors. All the bags were screened for HIV, HBsAg, HCV and VDRL and the plasma in the pilot tubes of the blood bags was observed to detect any abnormality in color. In 27 cases plasma was found to be icteric and liver function tests were carried out on these samples. Two donors showed higher SGPT level, and were excluded. No significant increases in liver enzymes were recorded in the others. Causes of icteric plasma in these apparently healthy donors are discussed. Differential diagnosis includes Gilbert’s disease, hemolytic anemia, drug-induced anemia and other hepatic causes of hyperbilirubinemia, of which Gilbert’s disease is most probable cause with a prevalence of 0.91% in our population. As there are no studies to document the safety of the recipients receiving such abnormal colored plasma as well as to document the hazards in its transfusion, the question arises whether to transfuse such units or not. This study highlights this dilemma. A reassessment of existing policies and regulations is merited. PMID:20808649

  11. Donor defects and small polarons on the TiO2(110) surface

    NASA Astrophysics Data System (ADS)

    Moses, P. G.; Janotti, A.; Franchini, C.; Kresse, G.; Van de Walle, C. G.

    2016-05-01

    The role of defects in the chemical activity of the rutile TiO2(110) surface remains a rich topic of research, despite the rutile (110) being one of the most studied surfaces of transition-metal oxides. Here, we present results from hybrid functional calculations that reconcile apparently disparate views on the impact of donor defects, such as oxygen vacancies and hydrogen impurities, on the electronic structure of the (110) rutile surface. We find that the bridging oxygen vacancy and adsorbed or substitutional hydrogen are actually shallow donors, which do not induce gap states. The excess electrons from these donor centers tend to localize in the form of small polarons, which are the factual cause of the deep states ˜1 eV below the conduction band, often observed in photoelectron spectroscopy measurements. Our results offer a new framework for understanding the surface electronic structure of TiO2 and related oxides.

  12. Changing Pattern of Donor Selection Criteria in Deceased Donor Liver Transplant: A Review of Literature

    PubMed Central

    Routh, Dronacharya; Naidu, Sudeep; Sharma, Sanjay; Ranjan, Priya; Godara, Rajesh

    2013-01-01

    During the last couple of decades, with standardization and progress in surgical techniques, immunosuppression and post liver transplantation patient care, the outcome of liver transplantation has been optimized. However, the principal limitation of transplantation remains access to an allograft. The number of patients who could derive benefit from liver transplantation markedly exceeds the number of available deceased donors. The large gap between the growing list of patients waiting for liver transplantation and the scarcity of donor organs has fueled efforts to maximize existing donor pool and identify new avenues. This article reviews the changing pattern of donor for liver transplantation using grafts from extended criteria donors (elderly donors, steatotic donors, donors with malignancies, donors with viral hepatitis), donation after cardiac death, use of partial grafts (split liver grafts) and other suboptimal donors (hypernatremia, infections, hypotension and inotropic support). PMID:25755521

  13. N-Heterocyclic carbene boranes are good hydride donors.

    PubMed

    Horn, Markus; Mayr, Herbert; Lacôte, Emmanuel; Merling, Everett; Deaner, Jordan; Wells, Sarah; McFadden, Timothy; Curran, Dennis P

    2012-01-01

    The nucleophilicity parameters (N) of 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene borane and 1,3-dimethylimidazol-2-ylidene borane are 9.55 and 11.88. This places N-heterocyclic carbene boranes (NHC-boranes) among the most nucleophilic classes of neutral hydride donors. Reductions of highly electron-poor C═N and C═C bonds provide hydrogenation products along with new, stable borylated products. The results suggest that NHC-boranes have considerable untapped potential as neutral organic reductants. PMID:22149270

  14. Hydrogenation apparatus

    DOEpatents

    Friedman, Joseph [Encino, CA; Oberg, Carl L [Canoga Park, CA; Russell, Larry H [Agoura, CA

    1981-01-01

    Hydrogenation reaction apparatus comprising a housing having walls which define a reaction zone and conduits for introducing streams of hydrogen and oxygen into the reaction zone, the oxygen being introduced into a central portion of the hydrogen stream to maintain a boundary layer of hydrogen along the walls of the reaction zone. A portion of the hydrogen and all of the oxygen react to produce a heated gas stream having a temperature within the range of from 1100.degree. to 1900.degree. C., while the boundary layer of hydrogen maintains the wall temperature at a substantially lower temperature. The heated gas stream is introduced into a hydrogenation reaction zone and provides the source of heat and hydrogen for a hydrogenation reaction. There also is provided means for quenching the products of the hydrogenation reaction. The present invention is particularly suitable for the hydrogenation of low-value solid carbonaceous materials to provide high yields of more valuable liquid and gaseous products.

  15. ADS pilot program Plan

    NASA Technical Reports Server (NTRS)

    Clauson, J.; Heuser, J.

    1981-01-01

    The Applications Data Service (ADS) is a system based on an electronic data communications network which will permit scientists to share the data stored in data bases at universities and at government and private installations. It is designed to allow users to readily locate and access high quality, timely data from multiple sources. The ADS Pilot program objectives and the current plans for accomplishing those objectives are described.

  16. Catalyzed borohydrides for hydrogen storage

    DOEpatents

    Au, Ming

    2012-02-28

    A hydrogen storage material and process is provided in which alkali borohydride materials are created which contain effective amounts of catalyst(s) which include transition metal oxides, halides, and chlorides of titanium, zirconium, tin, and combinations of the various catalysts. When the catalysts are added to an alkali borodydride such as a lithium borohydride, the initial hydrogen release point of the resulting mixture is substantially lowered. Additionally, the hydrogen storage material may be rehydrided with weight percent values of hydrogen at least about 9 percent.

  17. Donor solvent coal liquefaction with bottoms recycle at elevated pressure

    DOEpatents

    Bauman, Richard F.; Taunton, John W.; Anderson, George H.; Trachte, Ken L.; Hsia, Steve J.

    1982-01-01

    An improved process for liquefying solid carbonaceous materials wherein increased naphtha yields are achieved by effecting the liquefaction at a pressure within the range from about 1750 to about 2800 psig in the presence of recycled bottoms and a hydrogen-donor solvent containing at least 0.8 wt % donatable hydrogen. The liquefaction is accomplished at a temperature within the range from about 700.degree. to about 950.degree. F. The coal:bottoms ratio in the feed to liquefaction will be within the range from about 1:1 to about 5:1 and the solvent or diluent to total solids ratio will be at least 1.5:1 and preferably within the range from about 1.6:1 to about 3:1. The yield of naphtha boiling range materials increases as the pressure increases but generally reaches a maximum at a pressure within the range from about 2000 to about 2500 psig.

  18. Iridium-Catalyzed Hydrogen Transfer Reactions

    NASA Astrophysics Data System (ADS)

    Saidi, Ourida; Williams, Jonathan M. J.

    This chapter describes the application of iridium complexes to catalytic hydrogen transfer reactions. Transfer hydrogenation reactions provide an alternative to direct hydrogenation for the reduction of a range of substrates. A hydrogen donor, typically an alcohol or formic acid, can be used as the source of hydrogen for the reduction of carbonyl compounds, imines, and alkenes. Heteroaromatic compounds and even carbon dioxide have also been reduced by transfer hydrogenation reactions. In the reverse process, the oxidation of alcohols to carbonyl compounds can be achieved by iridium-catalyzed hydrogen transfer reactions, where a ketone or alkene is used as a suitable hydrogen acceptor. The reversible nature of many hydrogen transfer processes has been exploited for the racemization of alcohols, where temporary removal of hydrogen generates an achiral ketone intermediate. In addition, there is a growing body of work where temporary removal of hydrogen provides an opportunity for using alcohols as alkylating agents. In this chemistry, an iridium catalyst "borrows" hydrogen from an alcohol to give an aldehyde or ketone intermediate, which can be transformed into either an imine or alkene under the reaction conditions. Return of the hydrogen from the catalyst provides methodology for the formation of amines or C-C bonds where the only by-product is typically water.

  19. Critical Factors Associated With Missing Follow-Up Data for Living Kidney Donors in the United States.

    PubMed

    Schold, J D; Buccini, L D; Rodrigue, J R; Mandelbrot, D; Goldfarb, D A; Flechner, S M; Kayler, L K; Poggio, E D

    2015-09-01

    Follow-up care for living kidney donors is an important responsibility of the transplant community. Prior reports indicate incomplete donor follow-up information, which may reflect both donor and transplant center factors. New UNOS regulations require reporting of donor follow-up information by centers for 2 years. We utilized national SRTR data to evaluate donor and center-level factors associated with completed follow-up for donors 2008-2012 (n = 30 026) using multivariable hierarchical logistic models. We compared center follow-up compliance based on current UNOS standards using adjusted and unadjusted models. Complete follow-up at 6, 12, and 24 months was 67%, 60%, and 50% for clinical and 51%, 40%, and 30% for laboratory data, respectively, but have improved over time. Donor risk factors for missing laboratory data included younger age 18-34 (adjusted odds ratio [AOR] = 2.03, 1.58-2.60), black race (AOR = 1.17, 1.05-1.30), lack of insurance (AOR = 1.25, 1.15-1.36), lower educational attainment (AOR = 1.19, 1.06-1.34), >500 miles to center (AOR = 1.78, 1.60-1.98), and centers performing >40 living donor transplants/year (AOR = 2.20, 1.21-3.98). Risk-adjustment moderately shifted classification of center compliance with UNOS standards. There is substantial missing donor follow-up with marked variation by donor characteristics and centers. Although follow-up has improved over time, targeted efforts are needed for donors with selected characteristics and at centers with higher living donor volume. Adding adjustment for donor factors to policies regulating follow-up may function to provide more balanced evaluation of center efforts. PMID:25902877

  20. Hydrogen in anion vacancies of semiconductors

    SciTech Connect

    Du, Mao-Hua; Singh, David J

    2009-01-01

    Density functional calculations show that, depending on the anion size, hydrogen in anion vacancies of various II-VI semiconductors can be either two-fold or four-fold coordinated, and has either amphoteric or shallow donor character. In general, the multi-coordination of hydrogen in an anion vacancy is the indication of an anionic H, H { ion, in the relatively ionic environment. In more covalent semiconductors, H would form a single cation-H bond in the anion vacancy.

  1. Water's dual nature and its continuously changing hydrogen bonds.

    PubMed

    Henchman, Richard H

    2016-09-28

    A model is proposed for liquid water that is a continuum between the ordered state with predominantly tetrahedral coordination, linear hydrogen bonds and activated dynamics and a disordered state with a continuous distribution of multiple coordinations, multiple types of hydrogen bond, and diffusive dynamics, similar to that of normal liquids. Central to water's heterogeneous structure is the ability of hydrogen to donate to either one acceptor in a conventional linear hydrogen bond or to multiple acceptors as a furcated hydrogen. Linear hydrogen bonds are marked by slow, activated kinetics for hydrogen-bond switching to more crowded acceptors and sharp first peaks in the hydrogen-oxygen radial distribution function. Furcated hydrogens, equivalent to free, broken, dangling or distorted hydrogens, have barrierless, rapid kinetics and poorly defined first peaks in their hydrogen-oxygen radial distribution function. They involve the weakest donor in a local excess of donors, such that barrierless whole-molecule vibration rapidly swaps them between the linear and furcated forms. Despite the low number of furcated hydrogens and their transient existence, they are readily created in a single hydrogen-bond switch and free up the dynamics of numerous surrounding molecules, bringing about the disordered state. Hydrogens in the ordered state switch with activated dynamics to make the non-tetrahedral coordinations of the disordered state, which can also combine to make the ordered state. Consequently, the ordered and disordered states are both connected by diffusive dynamics and differentiated by activated dynamics, bringing about water's continuous heterogeneity. PMID:27447299

  2. Donor free radical explosive composition

    DOEpatents

    Walker, Franklin E. [15 Way Points Rd., Danville, CA 94526; Wasley, Richard J. [4290 Colgate Way, Livermore, CA 94550

    1980-04-01

    An improved explosive composition is disclosed and comprises a major portion of an explosive having a detonation velocity between about 1500 and 10,000 meters per second and a minor amount of a donor additive comprising an organic compound or mixture of organic compounds capable of releasing low molecular weight free radicals or ions under mechanical or electrical shock conditions and which is not an explosive, or an inorganic compound or mixture of inorganic compounds capable of releasing low molecular weight free radicals or ions under mechanical or electrical shock conditions and selected from ammonium or alkali metal persulfates.

  3. Gamete donors' expectations and experiences of contact with their donor offspring

    PubMed Central

    Kirkman, Maggie; Bourne, Kate; Fisher, Jane; Johnson, Louise; Hammarberg, Karin

    2014-01-01

    STUDY QUESTION What are the expectations and experiences of anonymous gamete donors about contact with their donor offspring? SUMMARY ANSWER Rather than consistently wanting to remain distant from their donor offspring, donors' expectations and experiences of contact with donor offspring ranged from none to a close personal relationship. WHAT IS KNOWN ALREADY Donor conception is part of assisted reproduction in many countries, but little is known about its continuing influence on gamete donors' lives. STUDY DESIGN, SIZE, DURATION A qualitative research model appropriate for understanding participants' views was employed; semi-structured interviews were conducted during January–March 2013. PARTICIPANTS/MATERIALS, SETTING, METHODS Before 1998, gamete donors in Victoria, Australia, were subject to evolving legislation that allowed them to remain anonymous or (from 1988) to consent to the release of identifying information. An opportunity to increase knowledge of donors' expectations and experiences of contact with their donor offspring recently arose in Victoria when a recommendation was made to introduce mandatory identification of donors on request from their donor offspring, with retrospective effect. Pre-1998 donors were invited through an advertising campaign to be interviewed about their views, experiences and expectations; 36 sperm donors and 6 egg donors participated. MAIN RESULTS AND THE ROLE OF CHANCE This research is unusual in achieving participation by donors who would not normally identify themselves to researchers or government inquiries. Qualitative thematic analysis revealed that most donors did not characterize themselves as parents of their donor offspring. Donors' expectations and experiences of contact with donor offspring ranged from none to a close personal relationship. LIMITATIONS, REASONS FOR CAUTION It is not possible to establish whether participants were representative of all pre-1998 donors. WIDER IMPLICATIONS OF THE FINDINGS Anonymous

  4. Quality improvement in the care of live liver donors: implementation of the Designated Donor Nurse Program.

    PubMed

    LaPointe Rudow, Dianne; Cabello, Charlotte C; Rivellini, Denise

    2010-12-01

    Publications on living donor liver transplant have focused on the medical aspects of donor selection, postoperative management, surgical procedures, and outcomes, but little attention has been given to the nursing implications for care of live liver donors during their inpatient stay. Donor advocates from various disciplines are involved during the initial education and evaluation, but most care after surgery is delivered by an inpatient medical team and bedside nursing staff who are not as familiar with the donor and concepts related to donor advocacy. In an effort to improve the overall donor experience and provide safe, high-quality care to patients undergoing elective partial hepatectomy, our academic medical center began a quality improvement project focused on improving the inpatient stay. Inpatient nursing standards and policies and procedures were developed to ensure that consistent care is delivered. However, the infrequency of living donor liver transplantation makes it nearly impossible to have all transplant program staff on a nursing unit be "experts" on donor care. Therefore, our center determined that, similar to the Independent Donor Advocacy Team, a transplant program needs live donor champions on the nursing unit to mirror the goals of the team. To that end, we developed the concept of the Designated Donor Nurse to care for and advocate for live liver donors during the inpatient stay and also to serve as a resource to their colleagues. PMID:21265291

  5. The living donor advocate: a team approach to educate, evaluate, and manage donors across the continuum.

    PubMed

    Rudow, Dianne LaPointe

    2009-03-01

    Living donor transplant has developed as a direct result of the critical shortage of deceased donors. Federal regulations require transplant programs to appoint an independent donor advocate to ensure safe evaluation and care of live donors. Ethical and pragmatic issues surround the donor advocate. These issues include the composition of a team versus an individual advocate, who appoints them, and the role that the advocate(s) play in the process. A team approach to donor advocacy is recommended. Common goals of the independent donor advocacy team should be protocol development, education, medical and psychosocial evaluation, advocacy, support, and documentation throughout the donation process. The team's involvement should not end with consent and donation but should continue through short- and long-term follow-up and management. Ultimately it is the goal of the independent donor advocacy team to assist donors to advocate for themselves. Once deemed medically and psychologically suitable, donors must determine for themselves what they wish to do and must be free to vocalize this to their team. The decision to donate or not affects the donor first. Optimal outcomes begin with prepared, educated, uncoerced, and motivated donors, and it is the team's goal to help donors reach this point. PMID:19341065

  6. Management of the inpatient canine blood donor.

    PubMed

    Hohenhaus, A E

    1992-12-01

    The availability of inpatient blood donors as a source for transfusion allows flexibility that is lacking in an outpatient program. Choosing the appropriate dog as a donor is essential to the success of a hospital blood bank. Once a dog becomes a blood donor, routine physical and clinicopathologic examinations are necessary to monitor the animal's health and to ensure the quality of blood products. PMID:1472767

  7. New supramolecular architectures using hydrogen bonding

    SciTech Connect

    Zimmerman, S.C.; Baloga, M.H.; Fenlon, E.E.; Murray, T.J.

    1993-12-31

    Heterocyclic compounds containing two and three adjacent hydrogen bond donor and acceptor sites in all possible arrangements have been synthesized. The strength and selectivity with which each compounds binds its complement has been determined. The incorporation of these heterocyclic subunits into large structures that form supramolecular assemblies will be described.

  8. The formation of shallow-donor distribution profiles in proton irradiation of silicon

    NASA Astrophysics Data System (ADS)

    Grekhov, I. V.; Kostina, L. S.; Lomasov, V. N.; Yusupova, Sh. A.; Belyakova, E. I.

    2014-12-01

    A study of the formation of shallow hydrogen-containing donors (hydrogen-related shallow thermal donors, STD(H)) in silicon under proton irradiation followed by annealing in a temperature range of 300-500°C is reported. The effect of postimplantation annealing regimes on the concentration distribution of shallow donors at various proton energies and fluences is examined. It is shown that the shape of the concentration profiles strongly varies with temperature and annealing duration when a fixed concentration of radiation defects is introduced and equally with energy and dose at a given annealing temperature. It is also shown that the process in which hydrogen-containing shallow donors are formed is accompanied by the appearance in n-type silicon of H-induced buried n'-layers, the formation of which near the pn junction in the high-resistivity n-base of diode structures allows the breakdown voltage of high-voltage pn junctions to be controlled. In the general case, this makes it possible to improve the characteristics of power silicon devices of various purposes.

  9. Innovations Without Added Costs

    ERIC Educational Resources Information Center

    Cereghino, Edward

    1974-01-01

    There is no question that we are in a tight money market, and schools are among the first institutions to feel the squeeze. Therefore, when a plan is offered that provides for innovations without added costs, its something worth noting. (Editor)

  10. What Value "Value Added"?

    ERIC Educational Resources Information Center

    Richards, Andrew

    2015-01-01

    Two quantitative measures of school performance are currently used, the average points score (APS) at Key Stage 2 and value-added (VA), which measures the rate of academic improvement between Key Stage 1 and 2. These figures are used by parents and the Office for Standards in Education to make judgements and comparisons. However, simple…

  11. Living-donor liver transplantation: current perspective.

    PubMed

    Lobritto, Steven; Kato, Tomoaki; Emond, Jean

    2012-11-01

    The disparity between the number of available deceased liver donors and the number of patients awaiting transplantation continues to be an ongoing issue predisposing to death on the liver transplant waiting list. Deceased donor shortage strategies including the use of extended donor-criteria deceased donor grafts, split liver transplants, and organs harvested after cardiac death have fallen short of organ demand. Efforts to raise donor awareness are ongoing, but the course has been arduous to date. Living donor transplantation is a means to access an unlimited donor organ supply and offers potential advantages to deceased donation. Donor safety remains paramount demanding improvements and innovations in both the donor and recipient operations to ensure superior outcomes. The specialty operation is best preformed at centers with specific expertise and shuttling of select patients to these centers supported by third party payers is critical. Training future surgeons at centers with this specific experience can help disseminate this technology to improve local availability. Ongoing research in immunosuppression minimization, withdrawal and tolerance induction may make living donation a desired first-line operation rather than a necessary albeit less-desirable option. This chapter summarizes the progress of living liver donation and its potential applications. PMID:23397534

  12. Living kidney donor experiences: implications for counselling.

    PubMed

    Walsh, A

    2004-01-01

    This study adds to previous, mostly quantitative, investigation into the experiences of living related kidney donors. Such investigation is important so that potential donors are supported effectively and donation programmes remain relevant and specific to need. Exploration takes place into donor decision-making processes and the most effective forms of professional support. A non-probability sampling technique highlighted eight living related kidney donors who were interviewed using a semi-structured interview format. Raw data was analysed through the qualitative technique of Interpretative Phenomenological Analysis. The decision to donate is made rapidly, decisively and rationally. Professional support provides reassurance to donors, particularly when experiencing acute psychological reaction. The need to provide support to the parents of living donors is specifically highlighted. A comprehensive range of Master Themes are generated through Interpretative Phenomenological Analysis and these reflect the complexity of the donation experience. This suggests donors are concerned with the management of psychological experience rather than with reviewing the appropriateness of an original decision to donate. Evidence indicates that concepts of attitude and self-efficacy belief can develop understanding of the psychological experience of being a living kidney donor. A counselling perspective, with Social Cognitive Theory at its core, is highlighted as a valid method for providing professional support to donors before and after surgery. PMID:15835410

  13. [Kidney transplant from living donors in children?].

    PubMed

    Ginevri, Fabrizio; Dello Strologo, Luca; Guzzo, Isabella; Belingheri, Mirco; Ghio, Luciana

    2011-01-01

    A living-donor kidney transplant offers a child at the terminal stages of renal disease better functional recovery and quality of life than an organ from a deceased donor. Before starting the procedure for a living-donor transplant, however, it is necessary to establish if it is really safe. There are diseases, such as focal segmental glomerulosclerosis, atypical HUS and membranoproliferative glomerulonephritis with dense deposits, for which living donation is not recommended given the high incidence of recurrence of the disease but also the frequent loss of the graft. Regarding the selection of the donor, an increased risk of acute rejection has been reported for donors older than 60-65 years and a worsening of the renal outcome if the donor's weight is equal to or less than the recipient's. Finally, it is necessary to take into consideration that complications may arise in the donor both in the perioperative period and in the long term. In conclusion, kidney transplant from a living donor is a natural choice within the pediatric setting. The parents, usually young and highly motivated to donate, are the ideal donors. However, although the risks associated with donation are minimal, they are not totally absent, and consequently it is mandatory to follow standardized procedures according to the guidelines issued by the Centro Nazionale Trapianti. PMID:21341241

  14. Introducing ADS Labs

    NASA Astrophysics Data System (ADS)

    Accomazzi, Alberto; Henneken, E.; Grant, C. S.; Kurtz, M. J.; Di Milia, G.; Luker, J.; Thompson, D. M.; Bohlen, E.; Murray, S. S.

    2011-05-01

    ADS Labs is a platform that ADS is introducing in order to test and receive feedback from the community on new technologies and prototype services. Currently, ADS Labs features a new interface for abstract searches, faceted filtering of results, visualization of co-authorship networks, article-level recommendations, and a full-text search service. The streamlined abstract search interface provides a simple, one-box search with options for ranking results based on a paper relevancy, freshness, number of citations, and downloads. In addition, it provides advanced rankings based on collaborative filtering techniques. The faceted filtering interface allows users to narrow search results based on a particular property or set of properties ("facets"), allowing users to manage large lists and explore the relationship between them. For any set or sub-set of records, the co-authorship network can be visualized in an interactive way, offering a view of the distribution of contributors and their inter-relationships. This provides an immediate way to detect groups and collaborations involved in a particular research field. For a majority of papers in Astronomy, our new interface will provide a list of related articles of potential interest. The recommendations are based on a number of factors, including text similarity, citations, and co-readership information. The new full-text search interface allows users to find all instances of particular words or phrases in the body of the articles in our full-text archive. This includes all of the scanned literature in ADS as well as a select portion of the current astronomical literature, including ApJ, ApJS, AJ, MNRAS, PASP, A&A, and soon additional content from Springer journals. Fulltext search results include a list of the matching papers as well as a list of "snippets" of text highlighting the context in which the search terms were found. ADS Labs is available at http://adslabs.org

  15. The interaction among donor characteristics, severity of liver disease and the cost of liver transplantation

    PubMed Central

    Salvalaggio, Paolo R.; Dzebisashvili, Nino; MacLeod, Kara E.; Lentine, Krista L.; Gheorghian, Adrian; Schnitzler, Mark A.; Hohmann, Samuel; Segev, Dorry L.; Gentry, Sommer E.; Axelrod, David A.

    2010-01-01

    Introduction Accurate assessment of the impact of donor quality on liver transplant (LT) costs has been limited by the lack of a large, multicenter study of detailed clinical and economic data. Methods A novel, retrospective database linking information from the University HealthSystem Consortium and the OPTN registry was analyzed using multivariate regression to determine the relationship between donor quality (assessed through the Donor Risk Index (DRI)), recipient illness severity, and total inpatient costs (transplant and all readmissions) for 1 year following LT. Results Cost data were available for 9,059 LT recipients. Increasing MELD score, higher DRI, simultaneous liver kidney transplant, female gender and prior liver transplant were associated with increasing cost of LT (P<0.05). MELD and DRI interact to synergistically increase the cost of LT (P<0.05). Donors in the highest DRI quartile added close to $12,000 to the cost of transplantation and nearly $22,000 to post-transplant costs in comparison to the lowest risk donors. Among the individual components of the DRI, donation after cardiac death (increased $20,769 vs. brain dead donors) had the greatest impact on transplant costs. Overall one year costs were increased in older donors, minority donors, nationally shared organs, and those with cold ischemic times 7–13 hours (p<0.05 for all) Conclusion Donor quality, as measured by the DRI, is an independent predictor of LT costs in the perioperative and post-operative periods. Centers in highly competitive regions who transplant higher MELD patients with high DRI livers may be particularly affected by the synergistic impact of these factors. PMID:21384505

  16. Hydrogen in semiconductors and metals

    SciTech Connect

    Nickel, N.H.; Jackson, W.B.; Bowman, R.C.; Leisure, R.G.

    1998-12-31

    Major highlights of the conference include further understanding of the structure of extended hydrogen clusters in semiconductors, switchable optical properties of metal-hydride films, reversible changes in the magnetic coupling in metallic superlattices, and increased lifetime of integrated circuits due to deuterium device passivation. Continued progress has also been achieved in understanding hydrogenation of defects in compound semiconductors and on surfaces. Total energy calculations in semiconductors have progressed sufficiently to predict energetics and vibration frequencies as measured by experiment. Similarly, electronic structure calculations of hydrogen-metal systems provide a deeper understanding of stability, bonding, and phase changes. Various nuclear techniques have been refined to yield important information regarding the concentration and transport of hydrogen in condensed matter. Finally, the interaction of hydrogen to create thermal donors has been used to create deep p-n junctions without the need for deep diffusion of dopants. The volume has been organized along the order of presentation within the conference. Similar methods and subjects have been grouped together. The authors have attempted to keep similar metal and semiconductor papers together in order to further promote cross-fertilization between the fields. Major categories include hydrogen on surfaces, theory and thermodynamics, hydrogen transport phenomena, nuclear characterization techniques, compound semiconductors, metal bulk, devices and applications, bulk silicon, and carbon and carbon-like materials. Separate abstracts were prepared for most papers.

  17. The end of donor anonymity: how genetic testing is likely to drive anonymous gamete donation out of business.

    PubMed

    Harper, Joyce C; Kennett, Debbie; Reisel, Dan

    2016-06-01

    Thousands of people worldwide have been conceived using donor gametes, but not all parents tell their children of their origin. Several countries now allow donor-conceived offspring to potentially know their genetic parent if they are informed of their donor-conceived status. At the same time, personal genetic testing is a rapidly expanding field. Over 3 million people have already used direct-to-consumer genetic testing to find information about their ancestry, and many are participating in international genetic genealogy databases that will match them with relatives. The increased prevalence of these technologies poses numerous challenges to the current practice of gamete donation. (i) Whether they are donating in a country that practices anonymous donation or not, donors should be informed that their anonymity is not guaranteed, as they may be traced if their DNA, or that of a relative, is added to a database. (ii) Donor-conceived adults who have not been informed of their status may find out that they are donor-conceived. (iii) Parents using donor conception need to be fully informed that their children's DNA will identify that they are not the biological parents and they should be encouraged to disclose the use of donor gametes to their children. Together, these concerns make urgent a wide-ranging societal conversation about how to best safeguard and promote the interests of donor-conceived offspring and protect the rights of donors. Specifically, there is a need to ensure that new genetic information is communicated in a way that promotes both the safety and the privacy rights of offspring and donors alike. All parties concerned must be aware that, in 2016, donor anonymity does not exist. PMID:27073260

  18. DGTI Register of Rare Donors

    PubMed Central

    Hustinx, Hein

    2014-01-01

    Summary For patients with antibodies against the most common blood groups a rapid and efficient supply of compatible erythrocyte concentrates is self-evident. But typically we have to make the greatest effort providing blood for these patients, which have made antibodies against common blood groups. There are however patients with antibodies against rare blood group antigens that need special blood. The supply of such blood can be very difficult and mostly time-consuming. For this reason we set up a database of blood donors with rare blood groups. Since 2005 the BTS SRC Berne Ltd. has run this database on behalf of the Swiss BTS SRC. After a reorganization and extension of the database, conducted during 2011/2012, the data file was renamed ‘DGTI Register of Rare Donors’ and is now run under the patronage of the German Society for Transfusion Medicine and Immunohematology (DGTI). PMID:25538534

  19. Nano-ferrites for Water Splitting: Unprecedented High Photocatalytic Hydrogen Production under Visible Light

    EPA Science Inventory

    In the present investigation, hydrogen production via water splitting by nano ferrites has been studied using ethanol as the sacrificial donor. The nano ferrite has shown great potential in hydrogen generation with hydrogen yield of 8275 9moles/h/ g of photocatalyst under visible...

  20. [Liver transplants from living donors].

    PubMed

    Rogiers, X; Danninger, F; Malagó, M; Knoefel, W T; Gundlach, M; Bassas, A; Burdelski, M; Broelsch, C E

    1996-03-01

    In this article the authors discuss the advantages of Living Related Liver Transplantation (LRLT), criteria for the selection of donors and the standard operation technique. Among a total of 241 liver transplantation (LTx), 42 LRLT were performed at the University of Hamburg between October 1, 1991 and December 19, 1994. The body weight of recipients for LRLT ranged from 4,6 to 39 kg, with 64,2% having less than 10 kg. The volume of the donor left lateral liver lobe ranged from 100 cc to 350 cc. The average one year survival rate among electively operated patients-status 3-4 (UNOS 1995 classification) was 86.7%, two year survival rate 83.3%. The main advantages of LRLT are consired the following: 1. Absence of mortality on the waiting list, 2. Optimal timing of the transplantation (elective procedure, patient in a good condition), 3. Excellent organ (no primary non function), 4. A possible immunologic advantage, 5. Relief of the waiting list for cadaveric organs, 6. Psychological benefit for the family, 7. Cost effectiveness. Potential candidates for living donation with more than one cardiovascular risk factors were excluded. Social and psychological reasons leading to rejection of candidates were as follows: unstable family structure, expected professional or financial difficulties after living donation or withdrawal from consent. LRLT gives parents of a child with TLD a chance to avoid the risk of death on the waiting list or primary non function of the graft. LRLT has therefore established an important place in pediatric liver transplantation. PMID:8768973

  1. Polarization of human donor corneas.

    PubMed

    Parekh, Mohit; Ruzza, Alessandro; Ferrari, Stefano; Salvalaio, Gianni; Elbadawy, Hossein; Ponzin, Diego; Lipari, Eugenio

    2016-06-01

    To investigate the de-orientation effect of DSAEK grafts by observing the cross patterns and polarization power of human donor corneas using a polarizing device (Lumaxis(®)). Forty human donor corneas were placed in small petri-plates with epithelial side facing up. Polarizing power (arbitrary unit) and crosses were monitored and recorded by the software. The tissue was marked at 'Superior' position to ensure that the base and the polarizer are in alignment with each other after the cut. The anterior lamellar cut was performed using microkeratome. The lenticule was placed back in the same position as marked to mimic the alignment. The tissue was further rotated by 45° ensuring that the base of the cornea and the polarizer were in alignment. The polarization power and 'crosses' were identified at each step. The average of forty corneas from pre-cut to post-45° angular change showed statistically significant difference (p < 0.05) in terms of polarizing power. The cross-shaped pattern deformed and lost the sharpness towards 45° angle. However, multiple variances in terms of 'cross-patterns' were observed throughout the study. Lumaxis(®) was able to determine the worst quality tissue in terms of polarization (no black zone and crosses). Despite the quality of cross pattern which can be used as an additional objective parameter to evaluate the optical properties of the corneal tissue, this preliminary study needs to be further justified in terms of clinical relevance whether polarization changes with oriented or de-oriented grafts have any effects and consequences on the visual acuity. PMID:26920874

  2. Hydrogen Production

    SciTech Connect

    2014-09-01

    This 2-page fact sheet provides a brief introduction to hydrogen production technologies. Intended for a non-technical audience, it explains how different resources and processes can be used to produce hydrogen. It includes an overview of research goals as well as “quick facts” about hydrogen energy resources and production technologies.

  3. Hydrogen sulfide prevents Abeta-induced neuronal apoptosis by attenuating mitochondrial translocation of PTEN.

    PubMed

    Cui, Weigang; Zhang, Yinghua; Yang, Chenxi; Sun, Yiyuan; Zhang, Min; Wang, Songtao

    2016-06-14

    Neuronal cell apoptosis is an important pathological change in Alzheimer's disease (AD). Hydrogen sulfide (H(2)S) is known to be a novel gaseous signaling molecule and a cytoprotectant in many diseases including AD. However, the molecular mechanism of the antiapoptosis activity of H(2)S in AD is not yet fully understood. The aim of the present study is to evaluate the inhibitory effects of H(2)S on Abeta (Aβ)-induced apoptosis and the molecular mechanisms underlying primary neuron cells. Our results showed that sodium hydrosulfide (NaHS), a donor of H(2)S, significantly ameliorated Aβ-induced cell apoptosis. NaHS also reversed the Aβ-induced translocation of the phosphatase and tensin homologs deleted on chromosome 10 (PTEN) from the cytosol to the mitochondria. Furthermore, H(2)S increased the level of p-AKT/AKT significantly. Interestingly, the antiapoptosis effects of H(2)S were blocked down by specific PI3K/AKT inhibitor wortmannin. In conclusion, these data indicate that H(2)S inhibits Aβ-induced neuronal apoptosis by attenuating mitochondrial translocation of PTEN and that activation of PI3K/AKT signaling pathway plays a critical role in H(2)S-mediated neuronal protection. Our findings provide a novel route into the molecular mechanisms of neuronal apoptosis in AD. PMID:27026591

  4. Reactivity of isomeric pyridinecarboxaldehydes in catalytic hydrogenation

    SciTech Connect

    Yansone, D.P.; Stonkus, V.V.; Leitis, L.Ya.

    1995-02-01

    It has been established by a quantum-chemical method (CNDO/2) that there are two possible mechanisms occurring in the vapor-phase hydrogenation of 2-, 3-, and 4-pyridinecarboxaldehydes in the presence of a copper-chromium catalyst at 180-300{degrees}C. One of these involves a donor-acceptor interaction of aldehyde with catalyst and the addition of hydrogen to the carbon atom of the carbonyl group at the first stage. The second possible mechanism is the synchronous addition of hydrogen to the carbon and oxygen of the carbonyl group of a weakly bound a aldehyde molecule with an unchanged electronic structure. 16 refs., 2 tabs.

  5. Advanced Hydrogen Liquefaction Process

    SciTech Connect

    Schwartz, Joseph; Kromer, Brian; Neu, Ben; Jankowiak, Jerome; Barrett, Philip; Drnevich, Raymond

    2011-09-28

    The project identified and quantified ways to reduce the cost of hydrogen liquefaction, and reduce the cost of hydrogen distribution. The goal was to reduce the power consumption by 20% and then to reduce the capital cost. Optimizing the process, improving process equipment, and improving ortho-para conversion significantly reduced the power consumption of liquefaction, but by less than 20%. Because the efficiency improvement was less than the target, the program was stopped before the capital cost was addressed. These efficiency improvements could provide a benefit to the public to improve the design of future hydrogen liquefiers. The project increased the understanding of hydrogen liquefaction by modeling different processes and thoroughly examining ortho-para separation and conversion. The process modeling provided a benefit to the public because the project incorporated para hydrogen into the process modeling software, so liquefaction processes can be modeled more accurately than using only normal hydrogen. Adding catalyst to the first heat exchanger, a simple method to reduce liquefaction power, was identified, analyzed, and quantified. The demonstrated performance of ortho-para separation is sufficient for at least one identified process concept to show reduced power cost when compared to hydrogen liquefaction processes using conventional ortho-para conversion. The impact of improved ortho-para conversion can be significant because ortho para conversion uses about 20-25% of the total liquefaction power, but performance improvement is necessary to realize a substantial benefit. Most of the energy used in liquefaction is for gas compression. Improvements in hydrogen compression will have a significant impact on overall liquefier efficiency. Improvements to turbines, heat exchangers, and other process equipment will have less impact.

  6. The Experience of Living Kidney Donors

    ERIC Educational Resources Information Center

    Brown, Judith Belle; Karley, Mary Lou; Boudville, Neil; Bullas, Ruth; Garg, Amit X.; Muirhead, Norman

    2008-01-01

    This article describes the experiences, feelings, and ideas of living kidney donors. Using a phenomenological, qualitative research approach, the authors interviewed 12 purposefully selected living kidney donors (eight men and four women), who were between four and 29 years since donation. Interviews were audiotaped, and transcribed verbatim, and…

  7. The value of living donor liver transplantation.

    PubMed

    Yang, Xiaoli; Gong, Junhua; Gong, JianPing

    2012-12-31

    Living donor liver transplantation (LDLT) is a very successful procedure that develops liver resources in case of worldwide shortages. As the technology has developed so much in the past 2 decades, LDLT has the same good prognosis as DDLT. However, LDLT still has lots of ethical & technical problems. It causes great psychiatric, physical and psychosocial harm to donors. Also, it has some negative effects on society by providing a platform for organ trade. Therefore, there is much controversy about the social value of LDLT. After review of recent papers, we find much progress can be made in inspiring the public to become organ donors and creating donation model new to improve the consent rate for solid organ donation from deceased donors. That is the key strategy for increasing the liver supply. With this serious shortage of organs, liver donor transplantation still has its advantages, but we should not place all our hopes on LDLT to increase the liver supply. We all need to try our best to increase donor awareness and promote organ donor registration--when cadaver organs could meet the needs for liver transplantation, living donor liver transplants would not be necessary. PMID:23274332

  8. Payment for donor kidneys: pros and cons.

    PubMed

    Friedman, E A; Friedman, A L

    2006-03-01

    Continuous growth of the end stage renal disease population treated by dialysis, outpaces deceased donor kidneys available, lengthens the waiting time for a deceased donor transplant. As estimated by the United States Department of Health & Human Services: '17 people die each day waiting for transplants that can't take place because of the shortage of donated organs.' Strategies to expand the donor pool--public relations campaigns and Drivers' license designation--have been mainly unsuccessful. Although illegal in most nations, and viewed as unethical by professional medical organizations, the voluntary sale of purchased donor kidneys now accounts for thousands of black market transplants. The case for legalizing kidney purchase hinges on the key premise that individuals are entitled to control of their body parts even to the point of inducing risk of life. One approach to expanding the pool of kidney donors is to legalize payment of a fair market price of about 40,000 dollars to donors. Establishing a federal agency to manage marketing and purchase of donor kidneys in collaboration with the United Network for Organ Sharing might be financially self-sustaining as reduction in costs of dialysis balances the expense of payment to donors. PMID:16482095

  9. 42 CFR 35.64 - Donors.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Donors. 35.64 Section 35.64 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES MEDICAL CARE AND EXAMINATIONS HOSPITAL AND STATION MANAGEMENT Contributions for the Benefit of Patients § 35.64 Donors. Authorized contributions...

  10. 42 CFR 35.64 - Donors.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Donors. 35.64 Section 35.64 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES MEDICAL CARE AND EXAMINATIONS HOSPITAL AND STATION MANAGEMENT Contributions for the Benefit of Patients § 35.64 Donors. Authorized contributions...

  11. 42 CFR 35.64 - Donors.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Donors. 35.64 Section 35.64 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES MEDICAL CARE AND EXAMINATIONS HOSPITAL AND STATION MANAGEMENT Contributions for the Benefit of Patients § 35.64 Donors. Authorized contributions...

  12. Recipients' views on payment of sperm donors.

    PubMed

    Ravelingien, An; Provoost, Veerle; Wyverkens, Elia; Buysse, Ann; De Sutter, Petra; Pennings, Guido

    2015-08-01

    The aim of this qualitative study was to explore how recipients viewed payment of sperm donors. The study was conducted in Belgium, where, as in many countries, sperm donors receive recompense for their time and expenses. Face-to-face semi-structured interviews were conducted with 34 heterosexual and lesbian couples who, at the time of data collection, had at least one donor-conceived child aged 7-10 years or who were undergoing donor conception treatment. Although participants commonly described the issue of financial compensation as something that did not really concern them, all supported the idea that some level of payment was acceptable or even necessary. The participants also identified several ways in which donor payment offered advantages to their own position as (future) parents. Although the idea is commonly rehearsed that sperm donation is a gift and that monetary transaction for conception is demeaning, the participants of this study did not generally share this view. To them, a small financial return served as a symbolic acknowledgement of the donor's contribution and helped secure the type of relationship they expected from their donor. There was clearly concern, however, over high payments and the risk of attracting the wrong kind of donor. PMID:26099446

  13. Negotiating boundaries: Accessing donor gametes in India

    PubMed Central

    Widge, A.; Cleland, J.

    2011-01-01

    Background: This paper documents how couples and providers access donor materials for conception in the Indian context and perceptions about using them. The objective is to facilitate understanding of critical issues and relevant concerns. Methods: A postal survey was conducted with a sample of 6000 gynaecologists and in-depth interviews were conducted with 39 gynaecologists in four cities. Results: Donor gametes are relatively more acceptable than a few years ago, especially if confidentiality can be maintained, though lack of availability of donor materials is sometimes an impediment to infertility treatment. Donor sperms are usually accessed from in-house or commercial sperm banks, pathology laboratories, IVF centres, professional donors, relatives or friends. There is scepticism about screening procedures of sperm banks. Donor eggs are usually accessed from voluntary donors, friends, relatives, egg sharing programmes, donation from other patients, advertising and commercial donors. There are several concerns regarding informed consent for using donated gametes, using relatives and friends gametes, the unregulated use of gametes and embryos, record keeping and documentation, unethical and corrupt practices and commercialisation. Conclusion: These issues need to be addressed by patients, providers and regulatory authorities by providing information, counselling, ensuring informed consent, addressing exploitation and commercialisation, ensuring monitoring, proper documentation and transparency. PMID:24753849

  14. Two Virasoro symmetries in stringy warped AdS3

    NASA Astrophysics Data System (ADS)

    Compère, Geoffrey; Guica, Monica; Rodriguez, Maria J.

    2014-12-01

    We study three-dimensional consistent truncations of type IIB supergravity which admit warped AdS3 solutions. These theories contain subsectors that have no bulk dynamics. We show that the symplectic form for these theories, when restricted to the non-dynamical subsectors, equals the symplectic form for pure Einstein gravity in AdS3. Consequently, for each consistent choice of boundary conditions in AdS3, we can define a consistent phase space in warped AdS3 with identical conserved charges. This way, we easily obtain a Virasoro × Virasoro asymptotic symmetry algebra in warped AdS3; two different types of Virasoro × Kač-Moody symmetries are also consistent alternatives.

  15. Chylous ascites secondary to laparoscopic donor nephrectomy.

    PubMed

    Shafizadeh, Stephen F; Daily, Patrick P; Baliga, Prabhakar; Rogers, Jeffrey; Baillie, G Mark; Rajagopolan, P R; Chavin, Kenneth D

    2002-08-01

    Live donor renal transplantation offers many significant advantages over cadaveric donor transplantation. Yet living donation continues to be underused, accounting for less than 30% of all donor renal transplants. In an attempt to remove the disincentives to live donation, Ratner et al. developed laparoscopic donor nephrectomy (LDN). LDN is gaining acceptance in the transplant community. The overriding concern must always be the safety and welfare of the donor. To this end, potential complications of LDN must be identified and discussed. We present a patient who developed the complication of chylous ascites from LDN. To improve the laparoscopic technique further, a discussion of its successes and complications needs to be encouraged. To this end, we present chylous ascites as a potential complication after LDN. We also offer suggestions to minimize the likelihood of this complication. PMID:12137847

  16. Non Heart-Beating Donors in England

    PubMed Central

    Chaib, Eleazar

    2008-01-01

    When transplantation started all organs were retrieved from patients immediately after cardio-respiratory arrest, i.e. from non-heart-beating donors. After the recognition that death resulted from irreversible damage to the brainstem, organ retrieval rapidly switched to patients certified dead after brainstem testing. These heart-beating-donors have become the principal source of organs for transplantation for the last 30 years. The number of heart-beating-donors are declining and this is likely to continue, therefore cadaveric organs from non-heart-beating donor offers a large potential of resources for organ transplantation. The aim of this study is to examine clinical outcomes of non-heart-beating donors in the past 10 years in the UK as an way of decreasing pressure in the huge waiting list for organs transplantation. PMID:18297216

  17. Kinetics of thermal donor generation in silicon

    NASA Technical Reports Server (NTRS)

    Mao, B.-Y.; Lagowski, J.; Gatos, H. C.

    1984-01-01

    The generation kinetics of thermal donors at 450 C in Czochralski-grown silicon was found to be altered by high-temperature preannealing (e.g., 1100 C for 30 min). Thus, when compared with as-grown Si, high-temperature preannealed material exhibits a smaller concentration of generated thermal donors and a faster thermal donor saturation. A unified mechanism of nucleation and oxygen diffusion-controlled growth (based on solid-state plate transformation theory) is proposed to account for generation kinetics of thermal donors at 450 C, in as-grown and high-temperature preannealed Czochralski silicon crystals. This mechanism is consistent with the main features of the models which have been proposed to explain the formation of oxygen thermal donors in silicon.

  18. Low severity coal conversion by ionic hydrogenation

    SciTech Connect

    Larsen, J.W.; Maioriello, J.; Cheng, J.C.

    1990-08-17

    The work accomplished in this project will be reported in two parts. Part one will focus on the development of catalytic ionic hydrogenation reactions utilizing a transition metal-H{sub 2} complex as the hydride donor and BF{sub 3}:H{sub 2}O as proton donor. This part reports the results of prelimiary work leading to the development of a new catalytic ionic hydrogenation system (MeCN){sub 2}PtCl{sub 2}/H{sub 2}/BF{sub 3}: H{sub 2}O. The results from some of this work have been published and the paper is included as the appendix. The second part focuses on the newly developed catalytic and other well characterized ionic hydrogenation reactions applied to lignites (Beulah-Zap), sub-bitumiuous (Wyodak), and bituminous coals (Pittsburgh {number sign}8). 19 refs., 10 tabs.

  19. Hydrogenation apparatus

    DOEpatents

    Friedman, J.; Oberg, C. L.; Russell, L. H.

    1981-06-23

    Hydrogenation reaction apparatus is described comprising a housing having walls which define a reaction zone and conduits for introducing streams of hydrogen and oxygen into the reaction zone, the oxygen being introduced into a central portion of the hydrogen stream to maintain a boundary layer of hydrogen along the walls of the reaction zone. A portion of the hydrogen and all of the oxygen react to produce a heated gas stream having a temperature within the range of from 1,100 to 1,900 C, while the boundary layer of hydrogen maintains the wall temperature at a substantially lower temperature. The heated gas stream is introduced into a hydrogenation reaction zone and provides the source of heat and hydrogen for a hydrogenation reaction. There also is provided means for quenching the products of the hydrogenation reaction. The present invention is particularly suitable for the hydrogenation of low-value solid carbonaceous materials to provide high yields of more valuable liquid and gaseous products. 2 figs.

  20. Formaldoxime hydrogen bonded complexes with ammonia and hydrogen chloride

    NASA Astrophysics Data System (ADS)

    Golec, Barbara; Mucha, Małgorzata; Sałdyka, Magdalena; Barnes, Austin; Mielke, Zofia

    2015-02-01

    An infrared spectroscopic and MP2/6-311++G(2d,2p) study of hydrogen bonded complexes of formaldoxime with ammonia and hydrogen chloride trapped in solid argon matrices is reported. Both 1:1 and 1:2 complexes between formaldoxime and ammonia, hydrogen chloride have been identified in the CH2NOH/NH3/Ar, CH2NOH/HCl/Ar matrices, respectively, their structures were determined by comparison of the spectra with the results of calculations. In the 1:1 complexes present in the argon matrices the OH group of formaldoxime acts as a proton donor for ammonia and the nitrogen atom acts as a proton acceptor for hydrogen chloride. In the 1:2 complexes ammonia or hydrogen chloride dimers interact both with the OH group and the nitrogen atom of CH2NOH to form seven membered cyclic structures stabilized by three hydrogen bonds. The theoretical spectra generally agree well with the experimental ones, but they seriously underestimate the shift of the OH stretch for the 1:1 CH2NOH⋯NH3 complex.

  1. The impact of the donors' and recipients' medical complications on living kidney donors' mental health.

    PubMed

    Timmerman, Lotte; Laging, Mirjam; Timman, Reinier; Zuidema, Willij C; Beck, Denise K; IJzermans, Jan N M; Betjes, Michiel G H; Busschbach, Jan J V; Weimar, Willem; Massey, Emma K

    2016-05-01

    A minority of living kidney donors (between 5-25%) have poor psychological outcomes after donation. There is mixed evidence on the influence of medical complications on these outcomes. We examined whether medical complications among donors and recipients predicted changes in donors' mental health (psychological symptoms and well-being) between predonation and 1 year postdonation. One-hundred and forty-five donors completed questionnaires on mental health predonation and 3 and 12 months postdonation. Number of recipient rehospitalizations and donor complications (none; minor; or severe) were obtained from medical records at 3 and 12 months after surgery. Multilevel regression analyses were used to examine the association between medical complications and changes in donors' mental health over time after controlling for sociodemographic characteristics. We found that donor complications (P = 0.003) and recipient rehospitalizations (P = 0.001) predicted an increase in donors' psychological symptoms over time. Recipient rehospitalizations also predicted a decrease in well-being (P = 0.005) over time; however, this relationship became weaker over time. We conclude that medical complications experienced by either the donor or recipient is a risk factor for deterioration in donors' mental health after living kidney donation. Professionals should monitor donors who experience medical complications and offer additional psychological support when needed. PMID:26895841

  2. Charge-Assisted Hydrogen-Bonded Networks

    NASA Astrophysics Data System (ADS)

    Ward, Michael D.

    The importance of hydrogen bonds is widely recognized because of their role in defining the structure and properties of many compounds, including water, proteins, DNA, and polymers. Hydrogen bonding also has emerged as a critical tool in solid-state chemistry, in which the versatility of organic synthesis has been combined with the structure-directing properties of hydrogen-bond donor-acceptor pairs to steer molecular assembly into networks that reflect the symmetries of their molecular constituents. Although these efforts have been largely empirical, the dominance of hydrogen bonding among the multitude of intermolecular forces often leads to predictable control of crystal structure. Although charge-assisted hydrogen bonds (donors and acceptors with ionic character that reinforce the electrostatic character of the hydrogen bond) have been recognized for decades, their use in network design, particularly for “crystal engineering,” has grown substantially in the past decade. The evidence suggests that charge-assisted hydrogen bonds introduce extraordinary robustness to molecular networks that reflects a combination of strong intermolecular forces and structural compliance, thus facilitating design of organic solid-state materials.

  3. Leading Change, Adding Value.

    PubMed

    Evans, Nick

    2016-09-12

    Essential facts Leading Change, Adding Value is NHS England's new nursing and midwifery framework. It is designed to build on Compassion in Practice (CiP), which was published 3 years ago and set out the 6Cs: compassion, care, commitment, courage, competence and communication. CiP established the values at the heart of nursing and midwifery, while the new framework sets out how staff can help transform the health and care sectors to meet the aims of the NHS England's Five Year Forward View. PMID:27615573

  4. [MODERN APPROACHES TO TREATMENT OF A DONOR'S WOUNDS IN THE INJURED PERSONS WITH THE BURNS].

    PubMed

    Pertsov, V I; Odnosteblytsya, O L; Ponomarenko, O V

    2016-03-01

    The impact of the treatment method proposed, using antioxidant therapy in patients, suffering the burns, on the speed and efficacy of the donor's wounds healing in their extremities was studied. In a control group of patients a standard treatment of the donor's wounds in extremities was conducted, while in the main group of patients the treatment was added with lymphotropic injection of antioxidant preparation Mexidol. Due to application of the method proposed, the wounds healing in the main group of the injured persons have had occurred significantly faster, than in the patients of a control group, and the complications of the wounds healing were absent. PMID:27514095

  5. Oocyte cryopreservation for donor egg banking.

    PubMed

    Cobo, Ana; Remohí, José; Chang, Ching-Chien; Nagy, Zsolt Peter

    2011-09-01

    Oocyte donation is an efficient alternative to using own oocytes in IVF treatment for different indications. Unfortunately, 'traditional' (fresh) egg donations are challenged with inefficiency, difficulties of synchronization, very long waiting periods and lack of quarantine measures. Given the recent improvements in the efficiency of oocyte cryopreservation, it is reasonable to examine if egg donation through oocyte cryopreservation has merits. The objective of the current manuscript is to review existing literature on this topic and to report on the most recent outcomes from two established donor cryobank centres. Reports on egg donation using slow freezing are scarce and though results are encouraging, outcomes are not yet comparable to a fresh egg donation treatment. Vitrification on the other hand appears to provide high survival rates (90%) of donor oocytes and comparable fertilization, embryo development, implantation and pregnancy rates to traditional (fresh) egg donation. Besides the excellent outcomes, the ease of use for both donors and recipients, higher efficiency, lower cost and avoiding the problem of synchronization are all features associated with the benefit of a donor egg cryobank and makes it likely that this approach becomes the future standard of care. Oocyte donation is one of the last resorts in IVF treatment for couples challenged with infertility problems. However, traditional (fresh) egg donation, as it is performed today, is not very efficient, as typically all eggs from one donor are given to only one recipient, it is arduous as it requires an excellent synchronization between the donor and recipient and there are months or years of waiting time. Because of the development of an efficient oocyte cryopreservation technique, it is now possible to cryo-store donor (as well as non-donor) eggs, maintaining their viability and allowing their use whenever there is demand. Therefore, creating a donor oocyte cryobank would carry many advantages

  6. Liver regeneration after living donor transplant

    PubMed Central

    Olthoff, Kim M.; Emond, Jean C.; Shearon, Tempie H.; Everson, Greg; Baker, Talia B.; Fisher, Robert A.; Freise, Chris E.; Gillespie, Brenda W.; Everhart, James E.

    2014-01-01

    Background & Aims Adult-to-adult living donors and recipients were studied to characterize patterns of liver growth and identify associated factors in a multicenter study. Methods 350 donors and 353 recipients in A2ALL (Adult to Adult Living Donor Liver Transplantation Cohort Study) transplanted between March 2003 and February 2010 were included. Potential predictors of 3-month liver volume included total and standard liver volumes (TLV, SLV), the model for end-stage liver disease (MELD) score (in recipients), remnant and graft size, remnant to donor and graft to recipient weight ratio (RDWR, GRWR), remnant/TLV, and graft/SLV. Results Among donors, 3-month absolute growth was 676±251g (mean± SD) and percent reconstitution was 80%±13%. Among recipients, GRWR was 1.3%±0.4% (8<0.8%). Graft weight was 60%±13% of SLV. Three-month absolute growth was 549±267g and percent reconstitution was 93%±18%. Predictors of greater 3-month liver volume included larger patient size (donors, recipients), larger graft volume (recipients), and larger TLV (donors). Donors with the smallest remnant/TLV ratios had larger than expected growth, but also had higher postoperative bilirubin and international normalized ratio at 7 and 30 days. In a combined donor-recipient analysis, donors had smaller 3-month liver volumes than recipients adjusted for patient size, remnant or graft volume, and TLV or SLV (p=0.004). Recipient graft failure in the first 90 days was predicted by poor graft function at day 7 (HR=4.50, p=0.001), but not by GRWR or graft fraction (p>0.90 for each). Conclusions Both donors and recipients had rapid yet incomplete restoration of tissue mass in the first 3 months, confirming previous reports. Recipients achieved a greater percentage of expected total volume. Patient size and recipient graft volume significantly influenced 3 month volumes. Importantly, donor liver volume is a critical predictor of the rate of regeneration, and donor remnant fraction impacts post

  7. The effect of an anti-hydrogen bond on Fermi resonance: A Raman spectroscopic study of the Fermi doublet ν1-ν12 of liquid pyridine

    NASA Astrophysics Data System (ADS)

    Li, Dong-Fei; Gao, Shu-Qin; Sun, Cheng-Lin; Li, Zuo-Wei

    2012-08-01

    The effects of an anti-hydrogen bond on the ν1-ν12 Fermi resonance (FR) of pyridine are experimentally investigated by using Raman scattering spectroscopy. Three systems, pyridine/water, pyridine/formamide, and pyridine/carbon tetrachloride, provide varying degrees of strength for the diluent-pyridine anti-hydrogen bond complex. Water forms a stronger anti-hydrogen bond with pyridine than with formamide, and in the case of adding non-polar solvent carbon tetrachloride, which is neither a hydrogen bond donor nor an acceptor and incapable of forming a hydrogen bond with pyridine, the intermolecular distance of pyridine will increase and the interaction of pyridine molecules will reduce. The dilution studies are performed on the three systems. Comparing with the values of the Fermi coupling coefficient W of the ring breathing mode ν1 and triangle mode ν12 of pyridine at different volume concentrations, which are calculated according to the Bertran equations, in three systems, we find that the solution with the strongest anti-hydrogen bond, water, shows the fastest change in the ν1-ν12 Fermi coupling coefficient W with the volume concentration varying, followed by the formamide and carbon tetrachloride solutions. These results suggest that the stronger anti-hydrogen bond-forming effect will cause a greater reduction in the strength of the ν1-ν12 FR of pyridine. According to the mechanism of the formation of an anti-hydrogen bond in the complexes and the FR theory, a qualitative explanation for the anti-hydrogen bond effect in reducing the strength of the ν1-ν12 FR of pyridine is given.

  8. Bright Solid-State Emission of Disilane-Bridged Donor-Acceptor-Donor and Acceptor-Donor-Acceptor Chromophores.

    PubMed

    Shimada, Masaki; Tsuchiya, Mizuho; Sakamoto, Ryota; Yamanoi, Yoshinori; Nishibori, Eiji; Sugimoto, Kunihisa; Nishihara, Hiroshi

    2016-02-01

    The development of disilane-bridged donor-acceptor-donor (D-Si-Si-A-Si-Si-D) and acceptor-donor-acceptor (A-Si-Si-D-Si-Si-A) compounds is described. Both types of compound showed strong emission (λem =ca. 500 and ca. 400 nm, respectively) in the solid state with high quantum yields (Φ: up to 0.85). Compound 4 exhibited aggregation-induced emission enhancement in solution. X-ray diffraction revealed that the crystal structures of 2, 4, and 12 had no intermolecular π-π interactions to suppress the nonradiative transition in the solid state. PMID:26822564

  9. Effects of different electron donor feeding patterns on TCE reductive dechlorination performance.

    PubMed

    Panagiotakis, I; Antoniou, K; Mamais, D; Pantazidou, M

    2015-03-01

    This study investigates how the feeding pattern of e(-) donors might affect the efficiency of enhanced in situ bioremediation in TCE-contaminated aquifers. A series of lab-scale batch experiments were conducted using butyrate or hydrogen gas (H2) as e(-) donor and a TCE-dechlorinating microbial consortium dominated by Dehalococcoides spp. The results of these experiments demonstrate that butyrate is similarly efficient for TCE dechlorination whether it is injected once or in doses. Moreover, the present work indicates that the addition of butyrate in great excess cannot be avoided, since it most likely provide, even indirectly, significant part of the H2 required. Furthermore, methanogenesis appears to be the major ultimate e(-) accepting process in all experiments, regardless the e(-) donor used and the feeding pattern. Finally, the timing of injection of H2 seems to significantly affect dechlorination performance, since the injection during the early stages improves VC-to-ETH dechlorination and reduce methanogenic activity. PMID:25613854

  10. Carbon Monoxide as an Electron Donor for the Biological Reduction of Sulphate

    PubMed Central

    Parshina, Sofiya N.; Sipma, Jan; Henstra, Anne Meint; Stams, Alfons J. M.

    2010-01-01

    Several strains of Gram-negative and Gram-positive sulphate-reducing bacteria (SRB) are able to use carbon monoxide (CO) as a carbon source and electron donor for biological sulphate reduction. These strains exhibit variable resistance to CO toxicity. The most resistant SRB can grow and use CO as an electron donor at concentrations up to 100%, whereas others are already severely inhibited at CO concentrations as low as 1-2%. Here, the utilization, inhibition characteristics, and enzymology of CO metabolism as well as the current state of genomics of CO-oxidizing SRB are reviewed. Carboxydotrophic sulphate-reducing bacteria can be applied for biological sulphate reduction with synthesis gas (a mixture of hydrogen and carbon monoxide) as an electron donor. PMID:20628586

  11. Donor deactivation in silicon nanostructures

    NASA Astrophysics Data System (ADS)

    Björk, Mikael T.; Schmid, Heinz; Knoch, Joachim; Riel, Heike; Riess, Walter

    2009-02-01

    The operation of electronic devices relies on the density of free charge carriers available in the semiconductor; in most semiconductor devices this density is controlled by the addition of doping atoms. As dimensions are scaled down to achieve economic and performance benefits, the presence of interfaces and materials adjacent to the semiconductor will become more important and will eventually completely determine the electronic properties of the device. To sustain further improvements in performance, novel field-effect transistor architectures, such as FinFETs and nanowire field-effect transistors, have been proposed as replacements for the planar devices used today, and also for applications in biosensing and power generation. The successful operation of such devices will depend on our ability to precisely control the location and number of active impurity atoms in the host semiconductor during the fabrication process. Here, we demonstrate that the free carrier density in semiconductor nanowires is dependent on the size of the nanowires. By measuring the electrical conduction of doped silicon nanowires as a function of nanowire radius, temperature and dielectric surrounding, we show that the donor ionization energy increases with decreasing nanowire radius, and that it profoundly modifies the attainable free carrier density at values of the radius much larger than those at which quantum and dopant surface segregation effects set in. At a nanowire radius of 15 nm the carrier density is already 50% lower than in bulk silicon due to the dielectric mismatch between the conducting channel and its surroundings.

  12. Hydrogen Optical Fiber Sensors

    SciTech Connect

    Lieberman, Robert A.; Beshay, Manal; Cordero, Steven R.

    2008-07-28

    Optically-based hydrogen sensors promise to deliver an added level of safety as hydrogen and fuel cell technologies enter the mainstream. More importantly, they offer reduced power consumption and lower cost, which are desirable for mass production applications such as automobiles and consumer appliances. This program addressed two of the major challenges previously identified in porous optrode-based optical hydrogen sensors: sensitivity to moisture (ambient humidity), and interference from the oxygen in air. Polymer coatings to inhibit moisture and oxygen were developed in conjunction with newer and novel hydrogen sensing chemistries. The results showed that it is possible to achieve sensitive hydrogen detection and rapid response with minimal interference from oxygen and humidity. As a result of this work, a new and more exciting avenue of investigation was developed: the elimination of the porous optrode and deposition of the sensor chemistry directly into the polymer film. Initial results have been promising, and open up a wider range of potential applications from extended optical fiber sensing networks, to simple plastic "stickers" for use around the home and office.

  13. Donor research in australia: challenges and promise.

    PubMed

    Masser, Barbara; Smith, Geoff; Williams, Lisa A

    2014-07-01

    Donors are the key to the core business of Blood Collection Agencies (BCAs). However, historically, they have not been a focus of research undertaken by these organizations. This model is now changing, with significant donor research groups established in a number of countries, including Australia. Donor research in the Australian Red Cross Blood Service (Blood Service) is concentrated in the Donor and Community Research (DCR) team. Cognizant of the complex and ever-changing landscape with regard to optimal donor management, the DCR team collaborates with academics located at universities around Australia to coordinate a broad program of research that addresses both short- and-long term challenges to the blood supply. This type of collaboration is not, however, without challenges. Two major collaborative programs of the Blood Service's research, focusing on i) the recruitment and retention of plasmapheresis donors and ii) the role of the emotion pride in donor motivation and return, are showcased to elucidate how the challenges of conducting collaborative BCA research can be met. In so doing, these and the other research programs described herein demonstrate how the Blood Service supports and contributes to research that not only revises operational procedures but also contributes to advances in basic science. PMID:25254025

  14. Donor Research in Australia: Challenges and Promise

    PubMed Central

    Masser, Barbara; Smith, Geoff; Williams, Lisa A.

    2014-01-01

    Summary Donors are the key to the core business of Blood Collection Agencies (BCAs). However, historically, they have not been a focus of research undertaken by these organizations. This model is now changing, with significant donor research groups established in a number of countries, including Australia. Donor research in the Australian Red Cross Blood Service (Blood Service) is concentrated in the Donor and Community Research (DCR) team. Cognizant of the complex and ever-changing landscape with regard to optimal donor management, the DCR team collaborates with academics located at universities around Australia to coordinate a broad program of research that addresses both short- and-long term challenges to the blood supply. This type of collaboration is not, however, without challenges. Two major collaborative programs of the Blood Service's research, focusing on i) the recruitment and retention of plasmapheresis donors and ii) the role of the emotion pride in donor motivation and return, are showcased to elucidate how the challenges of conducting collaborative BCA research can be met. In so doing, these and the other research programs described herein demonstrate how the Blood Service supports and contributes to research that not only revises operational procedures but also contributes to advances in basic science. PMID:25254025

  15. Dirac operator on fuzzy AdS2

    NASA Astrophysics Data System (ADS)

    Fakhri, Hossein; Imaanpur, Ali

    2003-03-01

    In this article we construct the chirality and Dirac operators on noncommutative AdS2. We also derive the discrete spectrum of the Dirac operator which is important in the study of the spectral triple associated to AdS2. It is shown that the degeneracy of the spectrum present in the commutative AdS2 is lifted in the noncommutative case. The way we construct the chirality operator is suggestive of how to introduce the projector operators of the corresponding projective modules on this space.

  16. An xp model on AdS2 spacetime

    NASA Astrophysics Data System (ADS)

    Molina-Vilaplana, Javier; Sierra, Germán

    2013-12-01

    In this paper we formulate the xp model on the AdS2 spacetime. We find that the spectrum of the Hamiltonian has positive and negative eigenvalues, whose absolute values are given by a harmonic oscillator spectrum, which in turn coincides with that of a massive Dirac fermion in AdS2. We extend this result to generic xp models which are shown to be equivalent to a massive Dirac fermion on spacetimes whose metric depend of the xp Hamiltonian. Finally, we construct the generators of the isometry group SO(2,1) of the AdS2 spacetime, and discuss the relation with conformal quantum mechanics.

  17. Living donor liver transplantation in Egypt

    PubMed Central

    Marwan, Ibrahim

    2016-01-01

    In Egypt there is no doubt that chronic liver diseases are a major health concern. Hepatitis C virus (HCV) prevalence among the 15−59 years age group is estimated to be 14.7%. The high prevalence of chronic liver diseases has led to increasing numbers of Egyptian patients suffering from end stage liver disease (ESLD), necessitating liver transplantation (LT). We reviewed the evolution of LT in Egypt and the current status. A single center was chosen as an example to review the survival and mortality rates. To date, deceased donor liver transplantation (DDLT) has not been implemented in any program though Egyptian Parliament approved the law in 2010. Living donor liver transplantation (LDLT) seemed to be the only logical choice to save many patients who are in desperate need for LT. By that time, there was increase in number of centers doing LDLT (13 centers) and increase in number of LDLT cases [2,400] with improvement of the results. Donor mortality rate is 1.66 per 1,000 donors; this comprised four donors in the Egyptian series. The exact recipient survival is not accurately known however, and the one-year, three-year and five-year survival were 73.17%, 70.83% and 64.16% respectively in the International Medical Center (IMC) in a series of 145 adult to adult living donor liver transplantation (AALDLT) cases. There was no donor mortality in this series. LDLT are now routinely and successfully performed in Egypt with reasonable donor and recipient outcomes. Organ shortage remains the biggest hurdle facing the increasing need for LT. Although LDLT had reasonable outcomes, it carries considerable risks to healthy donors. For example, it lacks cadaveric back up, and is not feasible for all patients. The initial success in LDLT should drive efforts to increase the people awareness about deceased organ donation in Egypt. PMID:27115003

  18. Living donor liver transplantation in Egypt.

    PubMed

    Amer, Khaled E; Marwan, Ibrahim

    2016-04-01

    In Egypt there is no doubt that chronic liver diseases are a major health concern. Hepatitis C virus (HCV) prevalence among the 15-59 years age group is estimated to be 14.7%. The high prevalence of chronic liver diseases has led to increasing numbers of Egyptian patients suffering from end stage liver disease (ESLD), necessitating liver transplantation (LT). We reviewed the evolution of LT in Egypt and the current status. A single center was chosen as an example to review the survival and mortality rates. To date, deceased donor liver transplantation (DDLT) has not been implemented in any program though Egyptian Parliament approved the law in 2010. Living donor liver transplantation (LDLT) seemed to be the only logical choice to save many patients who are in desperate need for LT. By that time, there was increase in number of centers doing LDLT (13 centers) and increase in number of LDLT cases [2,400] with improvement of the results. Donor mortality rate is 1.66 per 1,000 donors; this comprised four donors in the Egyptian series. The exact recipient survival is not accurately known however, and the one-year, three-year and five-year survival were 73.17%, 70.83% and 64.16% respectively in the International Medical Center (IMC) in a series of 145 adult to adult living donor liver transplantation (AALDLT) cases. There was no donor mortality in this series. LDLT are now routinely and successfully performed in Egypt with reasonable donor and recipient outcomes. Organ shortage remains the biggest hurdle facing the increasing need for LT. Although LDLT had reasonable outcomes, it carries considerable risks to healthy donors. For example, it lacks cadaveric back up, and is not feasible for all patients. The initial success in LDLT should drive efforts to increase the people awareness about deceased organ donation in Egypt. PMID:27115003

  19. Complications in 100 living-liver donors.

    PubMed Central

    Grewal, H P; Thistlewaite, J R; Loss, G E; Fisher, J S; Cronin, D C; Siegel, C T; Newell, K A; Bruce, D S; Woodle, E S; Brady, L; Kelly, S; Boone, P; Oswald, K; Millis, J M

    1998-01-01

    OBJECTIVE: A review of 100 living-liver donors was performed to evaluate the perisurgical complications of the procedure and thus to help quantify the risks to the donor. SUMMARY BACKGROUND DATA: Despite the advantages of living-donor liver transplantation (LDLT), the procedure has received criticism for the risk it imposes on healthy persons. A paucity of data exists regarding the complications and relative safety of the procedure. METHODS: One hundred LDLTs performed between November 1989 and November 1996 were reviewed. Donor data were obtained by chart review, anesthesia records, and the computerized hospital data base. Patient variables were compared by Fisher's exact test and the Student's t test. RESULTS: There were 57 women and 43 men with a median age of 29. Donors were divided into two groups: group A (first 50 donors), and group B (last 50 donors). There were 91 left lateral segments and 9 left lobes. There were no deaths. Fourteen major complications occurred in 13 patients; 9 occurred in group A and 5 in group B. Biliary complications consisted of five bile duct injuries (group A = 4, group B = 1) and two cut edge bile leaks. Complications were more common in left lobe resections (55%) than in left lateral segment grafts (10%). Minor complications occurred in 20% of patients. A significant reduction in overall complications (major and minor) was observed between the groups (group A, n = 24 [45%] vs. group B, n = 10 [20%]). In addition, surgical time and hospital stay were both significantly reduced. CONCLUSIONS: Although the procedure is safe, many LDLT donors have a perisurgical complication. Surgical experience and technical modifications have resulted in a significant reduction in these complications, however. To minimize the risks for these healthy donors, LDLT should be performed at institutions with extensive experience. PMID:9712567

  20. Catalytic hydrogenation of polyaromatic compounds using coke-oven gas instead of pure hydrogen

    SciTech Connect

    Braekman-Danheux, C.E.; Fontana, A.H.; Laurent, Ph.M.; Lolivier, Ph.

    1995-12-31

    In order to improve the economy of the conversion process of polyaromatic molecules to their hydroaromatics analogs, catalytic hydrogenation of phenanthrene has been carried out under pressure of different simulated coke-oven gases instead of pure hydrogen. The influence of reaction time, temperature and pressure on the hydrogenation yields and on the nature of the obtained products has been studied. Comparisons have been made with reaction with pure hydrogen in the same conditions. The influence of the different components of a real coke-oven gas has also been pointed out. The results indicate that coke-oven gas can be used if the goal is not to obtain perhydroaromatics compounds for a thermal cracking, but to give partly hydrogenated compounds to be used as hydrogen donor solvent in a coal liquefaction process. The results have been applied to coal-tar highly aromatic fractions.

  1. Hydrogen Generator

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Another spinoff from spacecraft fuel cell technology is the portable hydrogen generator shown. Developed by General Electric Company, it is an aid to safer operation of systems that use hydrogen-for example, gas chromatographs, used in laboratory analysis of gases. or flame ionization detectors used as $ollution monitors. The generator eliminates the need for high-pressure hydrogen storage bottles, which can be a safety hazard, in laboratories, hospitals and industrial plants. The unit supplies high-purity hydrogen by means of an electrochemical process which separates the hydrogen and oxygen in distilled water. The oxygen is vented away and the hydrogen gas is stored within the unit for use as needed. GE's Aircraft Equipment Division is producing about 1,000 of the generators annually.

  2. Reassessing Medical Risk in Living Kidney Donors

    PubMed Central

    Kumar, Vineeta; Matas, Arthur J.

    2015-01-01

    The short- and long-term effects of unilateral nephrectomy on living donors have been important considerations for 60 years. Short-term risk is well established (0.03% mortality and <1% risk of major morbidity), but characterization of long-term risk is evolving. Relative to the general population, risk of mortality, ESRD, hypertension, proteinuria, and cardiovascular disease is comparable or lower. However, new studies comparing previous donors with equally healthy controls indicate increased risk of metabolic derangements (particularly involving calcium homeostasis), renal failure, and possibly, mortality. We discuss how these results should be interpreted and their influence on the practice of living donor kidney transplantation. PMID:25255922

  3. Granulocyte kinetics in donors undergoing filtration leukapheresis.

    PubMed

    Rubins, J M; MacPherson, J L; Nusbacher, J; Wiltbank, T

    1976-01-01

    Normal blood donors undergoing filtration leukapheresis (FL) have a profound transient neutropenia early in the procedure which is followed by a "rebound" neutrophilia. This phenomenon occurs in unstimulated donors as well as in donors pretreated with either prednisone or dexamethasone. The mechanism for development of the neutropenia was investigated in volunteers throug a nylon filter at 37 C, a significant but transient neutropenia was observed. Plasma rendered cell and stroma-free achieved the same result indicating that plasma alone, when exposed to nylon fibers, is capable of producing neutropenia. PMID:1251458

  4. Interventional radiology in living donor liver transplant

    PubMed Central

    Cheng, Yu-Fan; Ou, Hsin-You; Yu, Chun-Yen; Tsang, Leo Leung-Chit; Huang, Tung-Liang; Chen, Tai-Yi; Hsu, Hsien-Wen; Concerjero, Allan M; Wang, Chih-Chi; Wang, Shih-Ho; Lin, Tsan-Shiun; Liu, Yueh-Wei; Yong, Chee-Chien; Lin, Yu-Hung; Lin, Chih-Che; Chiu, King-Wah; Jawan, Bruno; Eng, Hock-Liew; Chen, Chao-Long

    2014-01-01

    The shortage of deceased donor liver grafts led to the use of living donor liver transplant (LDLT). Patients who undergo LDLT have a higher risk of complications than those who undergo deceased donor liver transplantation (LT). Interventional radiology has acquired a key role in every LT program by treating the majority of vascular and non-vascular post-transplant complications, improving graft and patient survival and avoiding, in the majority of cases, surgical revision and/or re-transplant. The aim of this paper is to review indications, diagnostic modalities, technical considerations, achievements and potential complications of interventional radiology procedures after LDLT. PMID:24876742

  5. Oxidation of Molecular Hydrogen by a Chemolithoautotrophic Beggiatoa Strain

    PubMed Central

    2016-01-01

    ABSTRACT A chemolithoautotrophic strain of the family Beggiatoaceae, Beggiatoa sp. strain 35Flor, was found to oxidize molecular hydrogen when grown in a medium with diffusional gradients of oxygen, sulfide, and hydrogen. Microsensor profiles and rate measurements suggested that the strain oxidized hydrogen aerobically when oxygen was available, while hydrogen consumption under anoxic conditions was presumably driven by sulfur respiration. Beggiatoa sp. 35Flor reached significantly higher biomass in hydrogen-supplemented oxygen-sulfide gradient media, but hydrogen did not support growth of the strain in the absence of reduced sulfur compounds. Nevertheless, hydrogen oxidation can provide Beggiatoa sp. 35Flor with energy for maintenance and assimilatory purposes and may support the disposal of internally stored sulfur to prevent physical damage resulting from excessive sulfur accumulation. Our knowledge about the exposure of natural populations of Beggiatoaceae to hydrogen is very limited, but significant amounts of hydrogen could be provided by nitrogen fixation, fermentation, and geochemical processes in several of their typical habitats such as photosynthetic microbial mats and submarine sites of hydrothermal fluid flow. IMPORTANCE Reduced sulfur compounds are certainly the main electron donors for chemolithoautotrophic Beggiatoaceae, but the traditional focus on this topic has left other possible inorganic electron donors largely unexplored. In this paper, we provide evidence that hydrogen oxidation has the potential to strengthen the ecophysiological plasticity of Beggiatoaceae in several ways. Moreover, we show that hydrogen oxidation by members of this family can significantly influence biogeochemical gradients and therefore should be considered in environmental studies. PMID:26896131

  6. Feelings of living donors about adult-to-adult living donor liver transplantation.

    PubMed

    Kusakabe, Tomoko; Irie, Shinji; Ito, Naomi; Kazuma, Keiko

    2008-01-01

    This study investigated the feelings of living donors about adult-to-adult liver transplantation. We interviewed 18 donors about their feelings before and after transplantation using semistructured interviews and then conducted a content analysis of their responses. Before transplantation, many donors reported that they wanted recipients to live for the donor or his or her family, and there was no one else to donate. Many donors were not anxious, did not feel coerced, and did not consider donation dangerous. Some reported being excited at facing a new experience. Some said they would not mind whatever happens. Others were anxious or unsure about the operation. Diagnostic testing and preoperative blood banking were painful. Donors experienced increasing stress just before the operation. After transplantation, some donors verbalized feeling more grateful to others and that they gained maturity. Throughout the process, donors were concerned about their recipients. Our results suggest that donors might act for themselves or their family. It is important to recognize the varied responses of donors' feelings toward liver transplant recipients. PMID:18708830

  7. Donor Retention in Online Crowdfunding Communities: A Case Study of DonorsChoose.org

    PubMed Central

    Althoff, Tim; Leskovec, Jure

    2016-01-01

    Online crowdfunding platforms like DonorsChoose.org and Kick-starter allow specific projects to get funded by targeted contributions from a large number of people. Critical for the success of crowdfunding communities is recruitment and continued engagement of donors. With donor attrition rates above 70%, a significant challenge for online crowdfunding platforms as well as traditional offline non-profit organizations is the problem of donor retention. We present a large-scale study of millions of donors and donations on DonorsChoose.org, a crowdfunding platform for education projects. Studying an online crowdfunding platform allows for an unprecedented detailed view of how people direct their donations. We explore various factors impacting donor retention which allows us to identify different groups of donors and quantify their propensity to return for subsequent donations. We find that donors are more likely to return if they had a positive interaction with the receiver of the donation. We also show that this includes appropriate and timely recognition of their support as well as detailed communication of their impact. Finally, we discuss how our findings could inform steps to improve donor retention in crowdfunding communities and non-profit organizations. PMID:27077139

  8. ADS Development in Japan

    NASA Astrophysics Data System (ADS)

    Kikuchi, Kenji

    2010-06-01

    Accelerator driven nuclear transmutation system has been pursued to have a clue to the solution of high-level radioactive waste management. The concept consists of super conducting linac, sub-critical reactor and the beam window. Reference model is set up to 800MW thermal power by using 1.5GeV proton beams with considerations multi-factors such as core criticality. Materials damage is simulated by high-energy particle transport codes and so on. Recent achievement on irradiation materials experiment is stated and the differences are pointed out if core burn-up is considered or not. Heat balance in tank-type ADS indicates the temperature conditions of steam generator, the beam widow and cladding materials. Lead-bismuth eutectics demonstration has been conducted. Corrosion depth rate was shown by experiments.

  9. Supersymmetric warped AdS in extended topologically massive supergravity

    NASA Astrophysics Data System (ADS)

    Deger, N. S.; Kaya, A.; Samtleben, H.; Sezgin, E.

    2014-07-01

    We determine the most general form of off-shell N=(1,1) supergravity field configurations in three dimensions by requiring that at least one off-shell Killing spinor exists. We then impose the field equations of the topologically massive off-shell supergravity and find a class of solutions whose properties crucially depend on the norm of the auxiliary vector field. These are spacelike-squashed and timelike-stretched AdS3 for the spacelike and timelike norms, respectively. At the transition point where the norm vanishes, the solution is null warped AdS3. This occurs when the coefficient of the Lorentz-Chern-Simons term is related to the AdS radius by μℓ=2. We find that the spacelike-squashed AdS3 can be modded out by a suitable discrete subgroup of the isometry group, yielding an extremal black hole solution which avoids closed timelike curves.

  10. Analysis of Hybrid Hydrogen Systems: Final Report

    SciTech Connect

    Dean, J.; Braun, R.; Munoz, D.; Penev, M.; Kinchin, C.

    2010-01-01

    Report on biomass pathways for hydrogen production and how they can be hybridized to support renewable electricity generation. Two hybrid systems were studied in detail for process feasibility and economic performance. The best-performing system was estimated to produce hydrogen at costs ($1.67/kg) within Department of Energy targets ($2.10/kg) for central biomass-derived hydrogen production while also providing value-added energy services to the electric grid.

  11. Non-organ donors' attitudes toward incentives.

    PubMed

    Tumin, Makmor; Noh, Abdillah; Chong, Chin-Sieng; Lim, Soo-Kun; Abdullah, Nawi; Ng, Kok-Peng

    2013-01-01

    Malaysians indicating that they did not intend to become organ donors upon their death were surveyed regarding interest in non-fungible financial incentives to be granted to surviving family members. Among the 730 (56% of the total sample of 1311) indicating unwillingness to be donors, 29.6% (216/730) subsequently indicated that they would be willing donors if the government introduced policies that, upon their death, "rewarded your (their) family with incentives for your (their) deeds." Among the 69% (504/730) who insisted that they would not become organ donor even with incentive, nearly 80% (404/501) of them were able to identify relevant incentives they thought should be provided by the state to those who make organ donations upon death. The majority of both groups preferred the state provide medical benefits to a surviving family member, suggesting this may be an attractive policy option for the state to raise the deceased organ donation pool. PMID:23600843

  12. Living donor liver transplantation in the USA

    PubMed Central

    Testa, Giuliano

    2016-01-01

    Living donor liver transplant (LDLT) accounts for a small volume of the transplants in the USA. Due to the current liver allocation system based on the model for end-stage liver disease (MELD), LDLT has a unique role in providing life-saving transplantation for patients with low MELD scores and significant complications from portal hypertension, as well as select patients with hepatocellular carcinoma (HCC). Donor safety is paramount and has been a topic of much discussion in the transplant community as well as the general media. The donor risk appears to be low overall, with a favorable long-term quality of life. The latest trend has been a gradual shift from right-lobe grafts to left-lobe grafts to reduce donor risk, provided that the left lobe can provide adequate liver volume for the recipient. PMID:27115007

  13. KSC CENTER DIRECTOR ACCEPTS PLAQUE FOR RECORD-SETTING BONE MARROW DONOR REGISTRATION DRIVE

    NASA Technical Reports Server (NTRS)

    1996-01-01

    Kennedy Space Center's Bone Marrow Donor Registration Drive Chairman Dr. George A. Martin and Center Director Jay Honeycutt (left to right) accept a plaque from the Leukemia Society of America's Associate Executive Director Martin Bernstine and the American Red Cross' Southeast Regional Director Jeff Koenreich. Representatives from the American Red Cross and the Leukemia Society of America came to KSC to honor those involved in the record-setting Bone Marrow Donor Registration Drive held here earlier this year. Over 900 potential donors were added to the National Bone Marrow Registry as a result of the KSC drive. The drive established a new record for the most people registered in a single day for the American Red Cross in the three state region of which Florida is a part.

  14. The role of exogenous electron donors for accelerating 2,4,6-trichlorophenol biotransformation and mineralization.

    PubMed

    Yan, Ning; Li, Rongjie; Xu, Hua; Li, Ling; Yang, Lihui; Zhang, Yongming; Liu, Rui; Rittmann, Bruce E

    2016-06-01

    2,4,6-Trichlorophenol (TCP) is a biologically recalcitrant compound, but its biodegradation via reductive dechlorination can be accelerated by adding an exogenous electron donor. In this work, acetate and formate were evaluated for their ability to accelerate TCP reductive dechlorination, as well to accelerate mono-oxygenation of TCP's reduction product, phenol. Acetate and formate accelerated TCP reductive dechlorination, and the impact was proportional to the number of electron equivalents released by oxidation of the donor: 8 e(-) equivalents per mol for acetate, compared to 2 e(-) eq per mol for formate. The acceleration phenomenon was similar for phenol mono-oxygenation, and this increased the rate of TCP mineralization. Compared to endogenous electron equivalents generated by phenol mineralization, the impact of exogenous electron donor was stronger on a per-equivalent basis. PMID:27084768

  15. Utilization of Expanded Criteria Donors in Liver Transplantation

    PubMed Central

    Saidi, Reza F.

    2013-01-01

    Improvements in surgical techniques, immunosuppression, and post-transplantation patient care have led to the optimization of liver transplantation outcomes. However, the waiting list for liver transplantation is increasing at a greater pace. The large gap between the growing pool of patients waiting for liver transplantation and the scarcity of donor organs has fueled efforts to maximize existing donors and identify new sources. This article will be focused on the current state of liver transplantation using grafts from extended criteria donors (elderly donors, steatotic donors, donors with malignancies, donors with viral hepatitis) and from donation after cardiac death (DCD), as well as the use of partial grafts (split grafts and living-donor liver transplantation) and other suboptimal donors (donors with hypernatremia, infections, hypotension and inotropic support). Overall, broadened criteria for acceptable donor livers appear to lessen graft survival rates somewhat compared with rates for standard criteria organs. PMID:25013654

  16. Liver-specific deceased donor risk indices.

    PubMed

    Wang, Zifa; Hisatake, Garrett; Yang, Libin

    2014-02-01

    In order to assess the quality of the donor liver, procuring surgeons should accurately evaluate not only general donor risk indices, such as donor age, causes of brain death and cold ischemic time, but also consider the specific donor risk indices. In this review, we focus on liver-specific deceased donor risk indices, including liver steatosis, anti-hepatitis B core (HBc) positive or hepatitis C virus (HCV) positive donors, hypernatremia and anatomical variations. Liver steatosis is strongly associated with poor graft function after liver transplantation. Liver with more than 40-50% macrosteatosis should not be used. However, at present the quantity of fatty livers lack accepted standards. The computerized image analysis programs should be used to automate the determination of fat content in liver biopsy specimens. Liver grafts from anti-HBc positive donors can be safely used, preferentially in hepatitis B surface antigen (HBsAg) positive or anti-HBc/anti-HBs positive recipients. HCV positive allografts free from fibrosis or severe inflammation are a safe option for HCV positive recipients. The procurement team should consider liver biopsy to evaluate these HCV positive allografts. Donor serum sodium over 150 mm may predict a higher rate of graft primary non-functions. Recently, however, some investigators reported the sodium level likely has little clinical impact on post-transplant liver function. The incidence of hepatic artery variations has been reported to be approximately 30%. To avoid injuries, it is very important to know and identify these variations with precision at the time of organ procurement. PMID:24033790

  17. Denitrification potential in stream sediments impacted by acid mine drainage: effects of pH, various electron donors, and iron.

    PubMed

    Baeseman, J L; Smith, R L; Silverstein, J

    2006-02-01

    Acid mine drainage (AMD) contaminates thousands of kilometers of stream in the western United States. At the same time, nitrogen loading to many mountain watersheds is increasing because of atmospheric deposition of nitrate and increased human use. Relatively little is known about nitrogen cycling in acidic, heavy-metal-laden streams; however, it has been reported that one key process, denitrification, is inhibited under low pH conditions. The objective of this research was to investigate the capacity for denitrification in acidified streams. Denitrification potential was assessed in sediments from several Colorado AMD-impacted streams, ranging from pH 2.60 to 4.54, using microcosm incubations with fresh sediment. Added nitrate was immediately reduced to nitrogen gas without a lag period, indicating that denitrification enzymes were expressed and functional in these systems. First-order denitrification potential rate constants varied from 0.046 to 2.964 day(-1). The pH of the microcosm water increased between 0.23 and 1.49 pH units during denitrification. Additional microcosm studies were conducted to examine the effects of initial pH, various electron donors, and iron (added as ferrous and ferric iron). Decreasing initial pH decreased denitrification; however, increasing pH had little effect on denitrification rates. The addition of ferric and ferrous iron decreased observed denitrification potential rate constants. The addition of glucose and natural organic matter stimulated denitrification potential. The addition of hydrogen had little effect, however, and denitrification activity in the microcosms decreased after acetate addition. These results suggest that denitrification can occur in AMD streams, and if stimulated within the environment, denitrification might reduce acidity. PMID:16463131

  18. Denitrification potential in stream sediments impacted by acid mine drainage: Effects of pH, various electron donors, and iron

    USGS Publications Warehouse

    Baeseman, J.L.; Smith, R.L.; Silverstein, J.

    2006-01-01

    Acid mine drainage (AMD) contaminates thousands of kilometers of stream in the western United States. At the same time, nitrogen loading to many mountain watersheds is increasing because of atmospheric deposition of nitrate and increased human use. Relatively little is known about nitrogen cycling in acidic, heavy-metal-laden streams; however, it has been reported that one key process, denitrification, is inhibited under low pH conditions. The objective of this research was to investigate the capacity for denitrification in acidified streams. Denitrification potential was assessed in sediments from several Colorado AMD-impacted streams, ranging from pH 2.60 to 4.54, using microcosm incubations with fresh sediment. Added nitrate was immediately reduced to nitrogen gas without a lag period, indicating that denitrification enzymes were expressed and functional in these systems. First-order denitrification potential rate constants varied from 0.046 to 2.964 day-1. The pH of the microcosm water increased between 0.23 and 1.49 pH units during denitrification. Additional microcosm studies were conducted to examine the effects of initial pH, various electron donors, and iron (added as ferrous and ferric iron). Decreasing initial pH decreased denitrification; however, increasing pH had little effect on denitrification rates. The addition of ferric and ferrous iron decreased observed denitrification potential rate constants. The addition of glucose and natural organic matter stimulated denitrification potential. The addition of hydrogen had little effect, however, and denitrification activity in the microcosms decreased after acetate addition. These results suggest that denitrification can occur in AMD streams, and if stimulated within the environment, denitrification might reduce acidity. ?? Springer Science+Business Media, Inc. 2006.

  19. No-drain DIEP Flap Donor-site Closure Using Barbed Progressive Tension Sutures

    PubMed Central

    Nagarkar, Purushottam; Lakhiani, Chrisovalantis; Cheng, Angela; Lee, Michael; Teotia, Sumeet

    2016-01-01

    Background: The use of progressive tension sutures has been shown to be comparable to the use of abdominal drains in abdominoplasty. However, the use of barbed progressive tension sutures (B-PTSs) in deep inferior epigastric artery perforator (DIEP) flap donor-site closure has not been investigated. Methods: A retrospective chart review was performed on patients with DIEP flap reconstruction in a 3-year period at 2 institutions by 2 surgeons. Patients were compared by method of DIEP donor-site closure. Group 1 had barbed running progressive tension sutures without drain placement. Group 2 had interrupted progressive tension closure with abdominal drain placement (PTS-AD). Group 3 had closure with only abdominal drain placement (AD). Data collected included demographics, perioperative data, and postoperative outcomes. Results: Seventy-five patients underwent DIEP reconstruction (25 B-PTS, 25 PTS-AD, and 25 AD). Patient characteristics—age, body mass index, comorbidities, smoking status, and chemotherapy—were not significantly different between groups. Rate of seroma was 1.3% (B-PTS = 0%, PTS-AD = 4%, AD = 0%), wound dehiscence 16% (B-PTS = 8%, PTS-AD = 16%, AD = 24%), and umbilical necrosis 5.3% (B-PTS = 0%, PTS-AD = 0%, AD = 16%). No hematomas were observed in any patients. No statistically significant difference was found between complication rates across groups. Conclusions: Use of B-PTSs for abdominal closure after DIEP flap harvest can obviate the need for abdominal drains. Complication rates following this technique are not significantly different from closure using progressive tension suture and abdominal drain placement. This practice can prevent the use of abdominal drains, which can promote patient mobility, increase independence upon discharge, and contribute to patient satisfaction. PMID:27200234

  20. Molecular characterization of GYPB and RH in donors in the American Rare Donor Program.

    PubMed

    Vege, S; Westhoff, C M

    2006-01-01

    Transfusion of patients with sickle cell disease (SCD) has been a challenge in clinical transfusion medicine, especially when the required donor RBCs must be U- and negative for high-prevalence Rh phenotypes (hr(B), hr(S)). It is now possible to genotype donors to identify or confirm Uvar and U- phenotypes, as well as Rh hr(B)- and hrS- phenotypes, and to characterize the different RH backgrounds found in these donors. In a preliminary study of donors registered in the American Rare Donor Program, twelve different RH backgrounds were identified in eighteen hr(B)- or hr(S)- donors. These results, summarized in the current report, confirm the heterogeneous nature of these phenotypes and are relevant for selection of donor units for patients with antibodies to high-prevalence Rh antigens. Not all phenotypically similar units will be compatible, and matching the Rh genotype of the donor to the patient is important to prevent further Rh sensitization. Most donors referred were hr(B)- and carry at least one hybrid RHD-CE(3-7)-D gene that encodes a variant C antigen linked to RHCE*ceS that encodes the VS+V- phenotype. Surprisingly, the majority of donors were heterozygous, some even carrying conventional alleles, suggesting that the loss of expression of the hr(B) epitopes on RBCs is a dominant phenotype. Although antigen-matching of patients with SCD with donors for C, E, and K antigens has decreased the incidence of alloimmunization, some patients still become immunized to Rh antigens, indicating the units were not truly matched. RH genotyping can identify those patients with SCD who carry RH alleles that encode altered C, e, or D who are at risk for production of "apparent auto" and alloantibodies to Rh antigens. RH genotyping of alloimmunized patients with SCD, partnered with genotyping of donors, can identify compatible units that would also eliminate the risk of further Rh alloimmunization. PMID:17105364

  1. Predictors of donor follow-up after living donor liver transplantation.

    PubMed

    Brown, Robert S; Smith, Abigail R; Dew, Mary Amanda; Gillespie, Brenda W; Hill-Callahan, Peg; Ladner, Daniela P

    2014-08-01

    Donor safety in living liver donation is of paramount importance; however, information on long-term outcomes is limited by incomplete follow-up. We sought to ascertain factors that predicted postdonation follow-up in 456 living liver donors in the Adult-to-Adult Living Donor Liver Transplantation Cohort Study. Completed donor follow-up was defined as physical, phone, or laboratory contact at a given time point. Univariate and multivariate mixed effects logistic regression models, using donor and recipient demographic and clinical data and donor quality-of-life data, were developed to predict completed follow-up. Ninety percent of the donors completed their follow-up in the first 3 months, and 83% completed their follow-up at year 1; rates of completed follow-up ranged from 57% to 72% in years 2 to 7 and from 41% to 56% in years 8 to 10. The probability of completed follow-up in the first year was higher for white donors [odds ratio (OR) = 3.27, 95% confidence interval (CI) = 1.25-8.58] but lower for donors whose recipients had hepatitis C virus or hepatocellular carcinoma (OR = 0.34, 95% CI = 0.17-0.69). After the first year, an older age at donation predicted more complete follow-up. There were significant center differences at all time points (OR range = 0.29-10.11), with center variability in both returns for in-center visits and the use of phone/long-distance visits. Donor follow-up in the first year after donation was excellent but decreased with time. Predictors of follow-up varied with the time since donation. In conclusion, adapting best center practices (enhanced through the use of telephones and social media) to maintain contact with donors represents a significant opportunity to gain valuable information about long-term donor outcomes. PMID:24824858

  2. Recent advance in living donor liver transplantation.

    PubMed

    Hashikura, Yasuhiko; Kawasaki, Seiji; Miyagawa, Shinichi; Terada, Masaru; Ikegami, Toshihiko; Nakazawa, Yuichi; Urata, Koichi; Chisuwa, Hisanao; Ogino, Shiro; Makuuchi, Masatoshi

    2002-02-01

    Living donor liver transplantation (LDLT)has been performed in more than 2000 cases around the world. This procedure is considered to have certain advantages over cadaveric liver transplantation, because detailed preoperative evaluation of the donor liver is possible and superior graft quality is available. The indication has recently been widened to include adult patients. The results of LDLT have been reported to be very good. In this article,several considerations on LDLT,including living donor selection and application to adult patients, are discussed. Between June 1990 and March 2001, 143 patients underwent LDLT at Shinshu University Hospital. During this period, 160 patients were determined to be candidates for liver transplantation in our institution, and 185 candidates were evaluated as potential donors for these patients. Thirty-eight of 185 donor candidates were excluded for reasons including liver dysfunction and withdrawal of consent. The recipients included 60 adults, 50 (83%) of whom are currently alive. Taking into account the worldwide shortage of cadaveric organ donation,the importance of LDLT will probably never diminish. This procedure should be established on the basis of profound consideration of donor safety as well as accumulated expertise of hepatobiliary surgery. PMID:11865355

  3. Living donor transplant: wider selection criteria.

    PubMed

    Splendiani, G; Cipriani, S; Valeri, M; Torlone, N; Vega, A; Tullio, T; Condò, S; Dominijanni, S; Casciani, C U

    2004-04-01

    The availability of cadaveric donor organs is insufficient for actual needs. The organ demand increases by 20% per year. Living donor transplant (LDT) may be a valid therapeutical alternative provided one uses proper criteria. LDT provides many advantages, like improved patient and organ survival, short waiting time, and the possibility to carefully plan the procedure. Potential risks include perioperative mortality and renal dysfunction in the kidney donor. At present, kidney LDTs in Italy represent 8% of the total, with an organ survival rate of 97% after 1 year (vs 93% for cadaveric transplants) and donors mortality rate of almost null. Most LDTs are performed from kinsmen. Presently, law no. 458, 26 June 1967, is in force in Italy for kidney LDT and law no. 453, 16 December 1999, for liver LDT. The foundations of LDT are, of course, the recipient's condition, the donor's motivation, and the altruism of the donation. It is desirable that in the future an increasing number of LDT be performed, supported by a careful, widespread health education regarding organ donation from living subjects and by the possibility to obtain insurance for the donor, which has been considered but never provided by actual laws. PMID:15110560

  4. Donor identification 'kills gamete donation'? A response.

    PubMed

    Allan, Sonia

    2012-12-01

    Two Australian government inquiries have recently called for the release of information to donor-conceived people about their gamete donors. A national inquiry, recommended 'as a matter of priority' that uniform legislation to be passed nationwide. A state-based inquiry argued that all donor-conceived people should have access to information and called for the enactment of retrospective legislation that would override donor anonymity. This paper responds to an opinion piece published in Human Reproduction in October 2012 by Professor Pennings in which he criticized such recommendations and questioned the motives of people that advocate for information release. I answer the arguments of Pennings, and argue that all parties affected by donor conception should be considered, and a compromise reached. The contact veto system is one such compromise. I discuss the education and support services recommended by the Victorian government and question Pennings' assertions that legislation enabling information release will lead to a decrease in gamete donation. Finally, I rebut Pennings' assertion that there is a 'hidden agenda' behind the call for information release. There is no such agenda in my work. If there is from others, then it is their discriminatory views that need to be addressed, not the move toward openness and honesty or the call for information by donor-conceived people. PMID:23034154

  5. Improved performance in coprocessing through fundamental and mechanistic studies in hydrogen transfer and catalysis. Final report, September 26, 1989--March 31, 1993

    SciTech Connect

    Curtis, C.W.

    1993-12-31

    The key results obtained from this research project are given: (1) Hydrogen transfer from naphthenes to aromatics, coal and resid occurred at coprocessing temperatures and in a N{sub 2} atmosphere; (2) Hydrogen donors ranked in reactivity as cyclic olefins (nonaromatic hydroaromatic compounds) > hydroaromatic compounds > naphthenes. This ranking held regardless of the type of atmosphere, hydrogen or nitrogen, used; (3) Resids reduced by the Birch method transferred substantially more hydrogen to the aromatic acceptor than did the parent resids under coprocessing conditions; (4) Hydropretreatment of resids resulted in enhanced coal conversion compared to the parent resid; (5) Addition of hydrogen donors such as cyclic olefins or hydroaromatic donors increased the amount of coal conversion during coprocessing. Cyclic olefins and the active hydroaromatic donor, dihydroanthracene, showed the highest level of hydrogen donability. Tetralin and octahydroanthracene showed low reactivity; (6) Reduced resids were more effective in coprocessing than the parent resids, in terms of enhanced coal conversion; (7) Thermal and catalytic reactivity of cyclic olefins under nitrogen and hydrogen atmospheres was much higher than conventional hydroaromatic donors when no aromatic acceptor was present; (8) Reactivity of hydrogen donors was dependent upon the reactivity of the acceptor as well as that of the donors; (9) Three-ring hydrogen donors, dihydroanthracene and hexahydroanthracene, were most effective for transferring hydrogen to the Argonne coals while octahydroanthracene was the least reactive; (10) The kinetics data obtained for thermal and catalytic reactions involving cyclic olefins and hydroaromatic donors were adequately modeled by pseudo-first order kinetics; and (11) {Delta}G values calculated for cyclic olefins and hydroaromatic donors based on kinetics data adequately represented the reactivity observed experimentally.

  6. Selecting suitable solid organ transplant donors: Reducing the risk of donor-transmitted infections

    PubMed Central

    Jr, Christopher S Kovacs; Koval, Christine E; van Duin, David; de Morais, Amanda Guedes; Gonzalez, Blanca E; Avery, Robin K; Mawhorter, Steven D; Brizendine, Kyle D; Cober, Eric D; Miranda, Cyndee; Shrestha, Rabin K; Teixeira, Lucileia; Mossad, Sherif B

    2014-01-01

    Selection of the appropriate donor is essential to a successful allograft recipient outcome for solid organ transplantation. Multiple infectious diseases have been transmitted from the donor to the recipient via transplantation. Donor-transmitted infections cause increased morbidity and mortality to the recipient. In recent years, a series of high-profile transmissions of infections have occurred in organ recipients prompting increased attention on the process of improving the selection of an appropriate donor that balances the shortage of needed allografts with an approach that mitigates the risk of donor-transmitted infection to the recipient. Important advances focused on improving donor screening diagnostics, using previously excluded high-risk donors, and individualizing the selection of allografts to recipients based on their prior infection history are serving to increase the donor pool and improve outcomes after transplant. This article serves to review the relevant literature surrounding this topic and to provide a suggested approach to the selection of an appropriate solid organ transplant donor. PMID:25032095

  7. Selecting suitable solid organ transplant donors: Reducing the risk of donor-transmitted infections.

    PubMed

    Jr, Christopher S Kovacs; Koval, Christine E; van Duin, David; de Morais, Amanda Guedes; Gonzalez, Blanca E; Avery, Robin K; Mawhorter, Steven D; Brizendine, Kyle D; Cober, Eric D; Miranda, Cyndee; Shrestha, Rabin K; Teixeira, Lucileia; Mossad, Sherif B

    2014-06-24

    Selection of the appropriate donor is essential to a successful allograft recipient outcome for solid organ transplantation. Multiple infectious diseases have been transmitted from the donor to the recipient via transplantation. Donor-transmitted infections cause increased morbidity and mortality to the recipient. In recent years, a series of high-profile transmissions of infections have occurred in organ recipients prompting increased attention on the process of improving the selection of an appropriate donor that balances the shortage of needed allografts with an approach that mitigates the risk of donor-transmitted infection to the recipient. Important advances focused on improving donor screening diagnostics, using previously excluded high-risk donors, and individualizing the selection of allografts to recipients based on their prior infection history are serving to increase the donor pool and improve outcomes after transplant. This article serves to review the relevant literature surrounding this topic and to provide a suggested approach to the selection of an appropriate solid organ transplant donor. PMID:25032095

  8. Sperm donors describe the experience of contact with their donor-conceived offspring.

    PubMed

    Hertz, R; Nelson, M K; Kramer, W

    2015-01-01

    This study explores the attitudes and experiences of 57 sperm donors who responded to a survey posted online in the United States and indicated that they had had contact with their donor-conceived offspring or the parents of their donor-conceived offspring. On average, 18 years had elapsed since the respondents donated sperm. In the interim between donating and having contact with offspring, most had become curious about their offspring. Most made contact through a bank or online registry. Most respondents had communicated with at least one offspring at least once and most had exchanged photos with offspring. Approximately two-thirds had met in person once; the same proportion had communicated over email or text. Other forms of communication were less common. Almost half of the respondents now considered their donor-conceived offspring to be like a family member. At the same time, donors are respectful of the integrity of the family in which their offspring were raised. Donors with contact are open to having their partners and children know their donor-conceived offspring. Although contact is generally positive, donors report that establishing boundaries and defining the relationship can be very difficult. Some donors also urge those who are thinking of donating to consider the consequences and some suggest avoiding anonymity. There were no significant differences in attitudes and experiences between those who donated anonymously and those who had been identity-release for their offspring when they turned 18. PMID:26175887

  9. Expanding the live kidney donor pool: ethical considerations regarding altruistic donors, paired and pooled programs.

    PubMed

    Patel, Shaneel Rajendra; Chadha, Priyanka; Papalois, Vassilios

    2011-06-01

    In renal transplant, there is a well-known deficiency in organ supply relative to demand. Live donation provides superior results when compared with deceased donation including a better rate of graft success and fewer immunologic complications. This deficiency in organs leads to significant morbidity and mortality rates. Alternative avenues have been extensively explored that may expand the live donor pool. They include altruistic donation as well as paired and pooled exchange programs. Altruistic donation is a truly selfless act from a donor unknown to the recipient. Kidney paired donation involves 2 incompatible donor-recipient pairs swapping donors to produce compatibility. Pooled donation involves at least 2 pairs, and can take the form of domino chains in which altruistic input sets up a chain of transplants, in which each recipient's incompatible donor makes a donation for the next recipient. Despite application of these various methods, there lie extensive ethical issues surrounding them. Misconceptions frequently occur; for instance, the perceived benefit that donating an organ to a loved one is greater for a related donor than for an altruistic one. Additionally, it is frequently believed that immunologic incompatibility offers coerced donors liberation from surgery, and that overcoming these barriers by introducing exchange programs provides vulnerable donors less protection. This article explores these and other complex ethical issues surrounding the various methods of expanding the donor pool. The authors offer opinions that challenge the ethical issues and attempt to overcome those views that hinder progress in the field. PMID:21649566

  10. Sperm donors describe the experience of contact with their donor-conceived offspring

    PubMed Central

    Hertz, R.; Nelson, M.K.; Kramer, W.

    2015-01-01

    This study explores the attitudes and experiences of 57 sperm donors who responded to a survey posted online in the United States and indicated that they had had contact with their donor-conceived offspring or the parents of their donor-conceived offspring. On average, 18 years had elapsed since the respondents donated sperm. In the interim between donating and having contact with offspring, most had become curious about their offspring. Most made contact through a bank or online registry. Most respondents had communicated with at least one offspring at least once and most had exchanged photos with offspring. Approximately two-thirds had met in person once; the same proportion had communicated over email or text. Other forms of communication were less common. Almost half of the respondents now considered their donor-conceived offspring to be like a family member. At the same time, donors are respectful of the integrity of the family in which their offspring were raised. Donors with contact are open to having their partners and children know their donor-conceived offspring. Although contact is generally positive, donors report that establishing boundaries and defining the relationship can be very difficult. Some donors also urge those who are thinking of donating to consider the consequences and some suggest avoiding anonymity. There were no significant differences in attitudes and experiences between those who donated anonymously and those who had been identity-release for their offspring when they turned 18. PMID:26175887

  11. How Organ Donors are Different from Non-donors: Responsibility, Barriers, and Religious Involvement.

    PubMed

    Range, Lillian M; Brazda, Geoffrey F

    2015-12-01

    To see if religious involvement, previously linked to various health behaviors, was linked to organ donation, 143 ethnically diverse undergraduates stated whether they were registered donors (53% were), and completed measures of organ donation attitudes and religious involvement. Compared with non-donors, donors reported fewer barriers, more family responsibility, and more willingness to receive donor organs, but were not different in religious involvement. Even in 2014, when being a "good Samaritan" by agreeing to organ donation is as easy as checking one box on a driver's license application, religious involvement does not seem to be a factor in checking this box. PMID:25524413

  12. Hydrogen energy.

    PubMed

    Edwards, P P; Kuznetsov, V L; David, W I F

    2007-04-15

    The problem of anthropogenically driven climate change and its inextricable link to our global society's present and future energy needs are arguably the greatest challenge facing our planet. Hydrogen is now widely regarded as one key element of a potential energy solution for the twenty-first century, capable of assisting in issues of environmental emissions, sustainability and energy security. Hydrogen has the potential to provide for energy in transportation, distributed heat and power generation and energy storage systems with little or no impact on the environment, both locally and globally. However, any transition from a carbon-based (fossil fuel) energy system to a hydrogen-based economy involves significant scientific, technological and socio-economic barriers. This brief report aims to outline the basis of the growing worldwide interest in hydrogen energy and examines some of the important issues relating to the future development of hydrogen as an energy vector. PMID:17272235

  13. Value Added in English Schools

    ERIC Educational Resources Information Center

    Ray, Andrew; McCormack, Tanya; Evans, Helen

    2009-01-01

    Value-added indicators are now a central part of school accountability in England, and value-added information is routinely used in school improvement at both the national and the local levels. This article describes the value-added models that are being used in the academic year 2007-8 by schools, parents, school inspectors, and other…

  14. Per aspirin ad astra...

    PubMed

    Hartung, Thomas

    2009-12-01

    Taking the 110th anniversary of marketing of aspirin as starting point, the almost scary toxicological profile of aspirin is contrasted with its actual use experience. The author concludes that we are lucky that, in 1899, there was no regulatory toxicology. Adding, for the purpose of this article, a fourth R to the Three Rs, i.e. Realism, three reality-checks are carried out. The first one comes to the conclusion that the tools of toxicology are hardly adequate for the challenges ahead. The second one concludes that, specifically, the implementation of the EU REACH system is not feasible with these tools, mainly with regard to throughput. The third one challenges the belief that classical alternative methods, i.e. replacing animal test-based tools one by one, is actually leading to a new toxicology - it appears to change only patches of the patchwork, but not to overcome any inherent limitations other than ethical ones. The perspective lies in the Toxicology for the 21st Century initiatives, which aim to create a new approach from the scratch, by an evidence-based toxicology and a global "Human Toxicology Programme". PMID:20105011

  15. Day-of-surgery rejection of donors in living donor liver transplantation

    PubMed Central

    Hegab, Bassem; Abdelfattah, Mohamed Rabei; Azzam, Ayman; Mohamed, Hazem; Hamoudi, Waleed Al; Alkhail, Faisal Aba; Bahili, Hamad Al; Khalaf, Hatem; Sofayan, Mohammed Al; Sebayel, Mohammed Al

    2012-01-01

    AIM: To study diagnostic laparoscopy as a tool for excluding donors on the day of surgery in living donor liver transplantation (LDLT). METHODS: This study analyzed prospectively collected data from all potential donors for LDLT. All of the donors were subjected to a three-step donor evaluation protocol at our institution. Step one consisted of a clinical and social evaluation, including a liver profile, hepatitis markers, a renal profile, a complete blood count, and an abdominal ultrasound with Doppler. Step two involved tests to exclude liver diseases and to evaluate the donor’s serological status. This step also included a radiological evaluation of the biliary anatomy and liver vascular anatomy using magnetic resonance cholangiopancreatography and a computed tomography (CT) angiogram, respectively. A CT volumetric study was used to calculate the volume of the liver parenchyma. Step three included an ultrasound-guided liver biopsy. Between November 2002 and May 2009, sixty-nine potential living donors were assessed by open exploration prior to harvesting the planned part of the liver. Between the end of May 2009 and October 2010, 30 potential living donors were assessed laparoscopically to determine whether to proceed with the abdominal incision to harvest part of the liver for donation. RESULTS: Ninety-nine living donor liver transplants were attempted at our center between November 2002 and October 2010. Twelve of these procedures were aborted on the day of surgery (12.1%) due to donor findings, and eighty-seven were completed (87.9%). These 87 liver transplants were divided into the following groups: Group A, which included 65 transplants that were performed between November 2002 and May 2009, and Group B, which included 22 transplants that were performed between the end of May 2009 and October 2010. The demographic data for the two groups of donors were found to match; moreover, no significant difference was observed between the two groups of donors with

  16. Supergravity at the boundary of AdS supergravity

    NASA Astrophysics Data System (ADS)

    Amsel, Aaron J.; Compère, Geoffrey

    2009-04-01

    We give a general analysis of AdS boundary conditions for spin-3/2 Rarita-Schwinger fields and investigate boundary conditions preserving supersymmetry for a graviton multiplet in AdS4. Linear Rarita-Schwinger fields in AdSd are shown to admit mixed Dirichlet-Neumann boundary conditions when their mass is in the range 0≤|m|<1/2lAdS. We also demonstrate that mixed boundary conditions are allowed for larger masses when the inner product is “renormalized” accordingly with the action. We then use the results obtained for |m|=1/lAdS to explore supersymmetric boundary conditions for N=1 AdS4 supergravity in which the metric and Rarita-Schwinger fields are fluctuating at the boundary. We classify boundary conditions that preserve boundary supersymmetry or superconformal symmetry. Under the AdS/CFT dictionary, Neumann boundary conditions in d=4 supergravity correspond to gauging the superconformal group of the three-dimensional CFT describing M2-branes, while N=1 supersymmetric mixed boundary conditions couple the CFT to N=1 superconformal topologically massive gravity.

  17. Chemochromic Hydrogen Sensors

    NASA Technical Reports Server (NTRS)

    Wiggins, Bryan C.

    2007-01-01

    As fossil fuel supplies decline, hydrogen is quickly becoming an increasingly important fuel source. Currently hydrogen is the prime fuel of today's space vehicles (e.g., Space Shuttle) and featured as a fuel for some prototype vehicles such as the BMW seven series model. Hydrogen is a colorless, odorless gas with a 4% lower explosive limit which makes leak detection a priority. In an effort to support the use of hydrogen, a chemochromic (color changing) sensor was developed that is robust, simple to use, and does not require active operation. It can be made into a thin tape which can be conveniently used for leak detection at flanges, valves, or outlets. Chemochromic sensors can be either reversible or irreversible; however, irreversible chemochromic sensors will be analyzed in this report. The irreversible sensor is useful during hazardous operations when personnel cannot be present. To actively monitor leaks, testing of the irreversible sensor against environmental effects was completed and results indicated this material is suitable for outdoor use in the harsh beachside environment of Kennedy Space Center. The experiments in this report will give additional results to the environmental testing by adding solid rocket booster residue as a variable. The primary motivation for these experiments is to prepare the sensors for the launch pad environment at the Kennedy Space Center. In an effort to simulate the atmosphere at the pads before and after launch, the chemochromic sensors are exposed to solid rocket residue under various conditions.

  18. Donor Deferral Rates after the Implementation of a New German Blood Donor Questionnaire

    PubMed Central

    Müller-Steinhardt, Michael; Weidmann, Christian; Wiesneth, Markus; Weck, Eberhard; Seifried, Erhard; Brade, Joachim; Klüter, Harald

    2012-01-01

    Background The implementation of a new national German blood donor questionnaire was proposed to improve donor and recipient safety. Methods We compared deferral/exclusion rates of whole blood donors before (May 2010, n = 64,735) and after (May 2011, n = 71,687) the implementation of a new blood donor questionnaire. Considering seasonal variations, analysis was performed with respect to collection site (mobile vs. fixed), sex, donor status (first-time vs. repeat), age, and the frequencies of sexual risk behavior and other reasons for deferral. Results We observed a statistically significant increase (p < 0.001) of the overall deferral/exclusion rate from 6.2 to 8.1%, irrespective of type of collection site (fixed: from 6.0 to 8.5%; mobile: from 6.2 to 8.0%), sex (females: from 7.5 to 9.9%; males: from 5.1 to 6.6%), donor status (first-time donors: from 19.7 to 24.7%; repeat donors: from 4.6 to 6.3%) or age (18–29 years: from 9.1 to 11.7%; 60–71 years: from 5.1 to 6.6%). Confidential self-exclusion increased from 0.08 to 0.14% (p < 0.001). Besides risk behavior, various medical reasons could be identified that explain this increase. Conclusions The new blood donor questionnaire resulted in an increased deferral/exclusion of all donor groups. Thus the impact on future blood supply must be considered carefully, and long-term studies and investigation of donor acceptance will be needed. PMID:22896762

  19. The willed body donor interview project: medical student and donor expectations.

    PubMed

    Bohl, Michael; Holman, Alexis; Mueller, Dean A; Gruppen, Larry D; Hildebrandt, Sabine

    2013-01-01

    The Anatomical Donations Program at the University of Michigan Medical School (UMMS) has begun a multiphase project wherein interviews of donors will be recorded and later shown to medical students who participate in the anatomical dissection course. The first phase of this project included surveys of both current UMMS medical students and donors concerning their perceptions of such a program. A five-question survey administered via Qualtrics software was electronically mailed to all current medical students at UMMS, and a survey was mailed to registered and potential donors requesting information from the UMMS on anatomical donations. A total of 224 medical student responses (response rate 33%) and 54 donor responses (response rate 27%) were received. Seventy-four percent of students and 81% of donors reported they would participate in this program if it existed. Students and donors supported the implementation of this program for varying reasons, though many felt strongly they would not want to participate in a donor interview program. These qualitative results support those of previous studies that show a majority of students desire a closer personal relationship with the donor, and these are the first results to be reported on donor perceptions of a donor interview program. Although many students and donors are in favor of instituting this program, others feel strongly that such an experience could be traumatic. The causes of these differing reactions need to be further explored, and the opinions of those who object to this study will be respected by maintaining voluntary participation in future phases of this study. PMID:23109299

  20. TT virus among blood donors in Alexandria.

    PubMed

    Hashish, Mona H; El-Barrawy, Mohamed A; Mahmoud, Ola A; Abdel Rahman, Nader W

    2005-01-01

    TTV is a non enveloped, single-stranded, circular- DNA virus that has been assigned to the Family Circiniviridae. The primary mode of TTV transmission was proposed to be transfusion (and hence its name). Little is known about the clinical significance and the natural history of TTV infection. Hence, responsibility of the virus for specific liver disease is still debated. In our study, we tested ninety five blood donors attending Kom EL-Decka regional blood bank in Alexandria for the presence of TTV DNA in their sera by PCR technique. The same samples were tested for ALT and AST levels by colorimetric technique and for HBsAg and anti-HCV by the ELISA technique. Out of the 95 blood donors, 46 (48.4%) had TTV DNA in their sera. None of the 95 blood donors included in this study was positive for HBsAg, while 22 (23.2%) were anti-HCV positive. Out of the 22 anti-HCV positive blood donors, 13 (59.1%) were TTV DNA positive, while out of the 73 anti-HCV negative blood donors, 33 (45.2%) had TTV DNA in their sera. There was no statistically significant difference between the prevalence of TTV DNA and anti-HCV in blood donors. No biochemical evidence of liver disease potentially linked to the TTV infection was observed in our blood donors who were TTV DNA positive. Furthermore, the occurrence of elevated serum AST and ALT was most often linked to HCV rather than TTV. PMID:17187747

  1. Evaluation of the medically complex living kidney donor.

    PubMed

    Caliskan, Yasar; Yildiz, Alaattin

    2012-01-01

    Due to organ shortage and difficulties for availability of cadaveric donors, living donor transplantation is an important choice for having allograft. Live donor surgery is elective and easier to organize prior to starting dialysis thereby permitting preemptive transplantation as compared to cadaveric transplantation. Because of superior results with living kidney transplantation, efforts including the usage of "Medically complex living donors" are made to increase the availability of organs for donation. The term "Complex living donor" is probably preferred for all suboptimal donors where decision-making is a problem due to lack of sound medical data or consensus guidelines. Donors with advanced age, obesity, asymptomatic microhematuria, proteinuria, hypertension, renal stone disease, history of malignancy and with chronic viral infections consist of this complex living donors. This medical complex living donors requires careful evaluation for future renal risk. In this review we would like to present the major issues in the evaluation process of medically complex living kidney donor. PMID:22655169

  2. Energies and wave functions of an off-centre donor in hemispherical quantum dot: Two-dimensional finite difference approach and ritz variational principle

    NASA Astrophysics Data System (ADS)

    Nakra Mohajer, Soukaina; El Harouny, El Hassan; Ibral, Asmaa; El Khamkhami, Jamal; Assaid, El Mahdi

    2016-09-01

    Eigenvalues equation solutions of a hydrogen-like donor impurity, confined in a hemispherical quantum dot deposited on a wetting layer and capped by an insulating matrix, are determined in the framework of the effective mass approximation. Conduction band alignments at interfaces between quantum dot and surrounding materials are described by infinite height barriers. Ground and excited states energies and wave functions are determined analytically and via one-dimensional finite difference approach in case of an on-center donor. Donor impurity is then moved from center to pole of hemispherical quantum dot and eigenvalues equation is solved via Ritz variational principle, using a trial wave function where Coulomb attraction between electron and ionized donor is taken into account, and by two-dimensional finite difference approach. Numerical codes developed enable access to variations of donor total energy, binding energy, Coulomb correlation parameter, spatial extension and radial probability density with respect to hemisphere radius and impurity position inside the quantum dot.

  3. Asymptotically AdS spacetimes with a timelike Kasner singularity

    NASA Astrophysics Data System (ADS)

    Ren, Jie

    2016-07-01

    Exact solutions to Einstein's equations for holographic models are presented and studied. The IR geometry has a timelike cousin of the Kasner singularity, which is the less generic case of the BKL (Belinski-Khalatnikov-Lifshitz) singularity, and the UV is asymptotically AdS. This solution describes a holographic RG flow between them. The solution's appearance is an interpolation between the planar AdS black hole and the AdS soliton. The causality constraint is always satisfied. The entanglement entropy and Wilson loops are discussed. The boundary condition for the current-current correlation function and the Laplacian in the IR is examined. There is no infalling wave in the IR, but instead, there is a normalizable solution in the IR. In a special case, a hyperscaling-violating geometry is obtained after a dimensional reduction.

  4. All AdS7 solutions of type II supergravity

    NASA Astrophysics Data System (ADS)

    Apruzzi, Fabio; Fazzi, Marco; Rosa, Dario; Tomasiello, Alessandro

    2014-04-01

    In M-theory, the only AdS7 supersymmetric solutions are AdS7 × S 4 and its orbifolds. In this paper, we find and classify new supersymmetric solutions of the type AdS7 × M 3 in type II supergravity. While in IIB none exist, in IIA with Romans mass (which does not lift to M-theory) there are many new ones. We use a pure spinor approach reminiscent of generalized complex geometry. Without the need for any Ansatz, the system determines uniquely the form of the metric and fluxes, up to solving a system of ODEs. Namely, the metric on M 3 is that of an S 2 fibered over an interval; this is consistent with the Sp(1) R-symmetry of the holographically dual (1,0) theory. By including D8 brane sources, one can numerically obtain regular solutions, where topologically M 3 ≅ S 3.

  5. Worldsheet scattering in AdS3/CFT2

    NASA Astrophysics Data System (ADS)

    Sundin, Per; Wulff, Linus

    2013-07-01

    We confront the recently proposed exact S-matrices for AdS 3/ CFT 2 with direct worldsheet calculations. Utilizing the BMN and Near Flat Space (NFS) expansions for strings on AdS 3 × S 3 × S 3 × S 1 and AdS 3 × S 3 × T 4 we compute both tree-level and one-loop scattering amplitudes. Up to some minor issues we find nice agreement in the tree-level sector. At the one-loop level however we find that certain non-zero tree-level processes, which are not visible in the exact solution, contribute, via the optical theorem, and give an apparent mismatch for certain amplitudes. Furthermore we find that a proposed one-loop modification of the dressing phase correctly reproduces the worldsheet calculation while the standard Hernandez-Lopez phase does not. We also compute several massless to massless processes.

  6. Detailed ultraviolet asymptotics for AdS scalar field perturbations

    NASA Astrophysics Data System (ADS)

    Evnin, Oleg; Jai-akson, Puttarak

    2016-04-01

    We present a range of methods suitable for accurate evaluation of the leading asymptotics for integrals of products of Jacobi polynomials in limits when the degrees of some or all polynomials inside the integral become large. The structures in question have recently emerged in the context of effective descriptions of small amplitude perturbations in anti-de Sitter (AdS) spacetime. The limit of high degree polynomials corresponds in this situation to effective interactions involving extreme short-wavelength modes, whose dynamics is crucial for the turbulent instabilities that determine the ultimate fate of small AdS perturbations. We explicitly apply the relevant asymptotic techniques to the case of a self-interacting probe scalar field in AdS and extract a detailed form of the leading large degree behavior, including closed form analytic expressions for the numerical coefficients appearing in the asymptotics.

  7. New massive gravity and AdS(4) counterterms.

    PubMed

    Jatkar, Dileep P; Sinha, Aninda

    2011-04-29

    We show that the recently proposed Dirac-Born-Infeld extension of new massive gravity emerges naturally as a counterterm in four-dimensional anti-de Sitter space (AdS(4)). The resulting on-shell Euclidean action is independent of the cutoff at zero temperature. We also find that the same choice of counterterm gives the usual area law for the AdS(4) Schwarzschild black hole entropy in a cutoff-independent manner. The parameter values of the resulting counterterm action correspond to a c=0 theory in the context of the duality between AdS(3) gravity and two-dimensional conformal field theory. We rewrite this theory in terms of the gauge field that is used to recast 3D gravity as a Chern-Simons theory. PMID:21635026

  8. Phases of global AdS black holes

    NASA Astrophysics Data System (ADS)

    Basu, Pallab; Krishnan, Chethan; Subramanian, P. N. Bala

    2016-06-01

    We study the phases of gravity coupled to a charged scalar and gauge field in an asymptotically Anti-de Sitter spacetime ( AdS 4) in the grand canonical ensemble. For the conformally coupled scalar, an intricate phase diagram is charted out between the four relevant solutions: global AdS, boson star, Reissner-Nordstrom black hole and the hairy black hole. The nature of the phase diagram undergoes qualitative changes as the charge of the scalar is changed, which we discuss. We also discuss the new features that arise in the extremal limit.

  9. International rare donor panels: a review.

    PubMed

    Nance, S; Scharberg, E A; Thornton, N; Yahalom, V; Sareneva, I; Lomas-Francis, C

    2016-04-01

    International rare blood donor panels or registries are important in the consistent availability of rare blood for patients who need this scarce resource. In countries where it has been possible to commit resources to this effort and often where the need is great, donors have been entered into a registry. The ISBT leadership recognized the importance of this very challenging inventory management activity and created a Working Party to support it. Individual countries support the WHO International Rare Donor Panel by submitting their donors' phenotype or genotype information to be catalogued into the database. It is extremely important that this database be cultivated and grown. The contributing countries keep their list updated and supply the blood product as they can when requested. It is known that some blood types are extremely scarce worldwide and requests for these are particularly difficult to fulfil. Thus, it is important to have a protocol to identify and recruit donors with rare blood types. It is equally or perhaps more important to ensure that the patients who need the rare blood are being managed appropriately in the presence and absence of rare blood products being available. PMID:26689301

  10. The Effect of Donor Age on Corneal Transplantation Outcome: Results of the Cornea Donor Study

    PubMed Central

    2009-01-01

    Objective To determine whether graft survival over a 5-year follow-up period using corneal tissue from donors older than 65 years of age is similar to graft survival using corneas from younger donors. Design Multi-center prospective, double-masked, controlled clinical trial Participants 1090 subjects undergoing corneal transplantation for a moderate risk condition (principally Fuchs’ dystrophy or pseudophakic corneal edema); 11 subjects with ineligible diagnoses were not included Methods 43 participating eye banks provided corneas from donors in the age range of 12 to 75 with endothelial cell densities of 2300 to 3300 cells/mm2, using a random approach without respect to recipient factors. The 105 participating surgeons at 80 sites were masked to information about the donor cornea including donor age. Surgery and post-operative care were performed according to the surgeons’ usual routines. Subjects were followed for five years. Main Outcome Measures Graft failure, defined as a regraft or a cloudy cornea that was sufficiently opaque as to compromise vision for a minimum of three consecutive months. Results The 5-year cumulative probability of graft survival was 86% in both the <66.0 donor age group and the ≥66.0 donor age group (difference = 0%, upper limit of one-sided 95% confidence interval = 4%). In a statistical model with donor age as a continuous variable, there was not a significant relationship between donor age and outcome (P=0.11). Three graft failures were due to primary donor failure, 8 to uncorrectable refractive error, 48 to graft rejection, 46 to endothelial decompensation (23 of which had a prior, resolved episode of probable or definite graft rejection), and 30 to other causes. The distribution of the causes of graft failure did not differ between donor age groups. Conclusions Five-year graft survival for cornea transplants at moderate risk for failure is similar using corneas from donors ≥ 66.0 years and donors < 66.0 years. Surgeons and

  11. Hydrogen Effect against Hydrogen Embrittlement

    NASA Astrophysics Data System (ADS)

    Murakami, Yukitaka; Kanezaki, Toshihiko; Mine, Yoji

    2010-10-01

    The well-known term “hydrogen embrittlement” (HE) expresses undesirable effects due to hydrogen such as loss of ductility, decreased fracture toughness, and degradation of fatigue properties of metals. However, this article shows, surprisingly, that hydrogen can have an effect against HE. A dramatic phenomenon was found in which charging a supersaturated level of hydrogen into specimens of austenitic stainless steels of types 304 and 316L drastically improved the fatigue crack growth resistance, rather than accelerating fatigue crack growth rates. Although this mysterious phenomenon has not previously been observed in the history of HE research, its mechanism can be understood as an interaction between hydrogen and dislocations. Hydrogen can play two roles in terms of dislocation mobility: pinning (or dragging) and enhancement of mobility. Competition between these two roles determines whether the resulting phenomenon is damaging or, unexpectedly, desirable. This finding will, not only be the crucial key factor to elucidate the mechanism of HE, but also be a trigger to review all existing theories on HE in which hydrogen is regarded as a dangerous culprit.

  12. The Psychosocial and Independent Living Donor Advocate Evaluation and Post-surgery Care of Living Donors.

    PubMed

    Rudow, Dianne LaPointe; Swartz, Kathleen; Phillips, Chelsea; Hollenberger, Jennifer; Smith, Taylor; Steel, Jennifer L

    2015-09-01

    Solid organ transplantation as a treatment for end stage organ failure has been an accepted treatment option for decades. Despite advances in medicine and technology, and increased awareness of organ donation and transplantation, the gap between supply and demand continues to widen. Living donation has been an option that has increased the number of transplants despite the continued shortage of deceased organs. In the early 2000s live donor transplantation reached an all-time high in the United States. As a result, a consensus meeting was convened in 2000 to increase the oversight of living donor transplantation. Both the Centers for Medicare and Medicaid Services and the United Network for Organ Sharing developed regulations that transplant programs performing live donor transplantation. These regulations and guidelines involve the education, evaluation, informed consent process and living donor follow-up care. Two areas in which had significant changes included the psychosocial and the independent living donor advocate (ILDA) evaluation. The purpose of this paper was to outline the current regulations and guidelines associated with the psychosocial and ILDA evaluation as well as provide further recommendations for the administration of a high quality evaluation of living donors. The goals and timing of the evaluation and education of donors; qualifications of the health care providers performing the evaluation; components of the evaluation; education provided to donors; documentation of the evaluation; participation in the selection committee meeting; post-decline and post-donation care of donors is described. Caveats including the paired donor exchange programs and non-directed and directed donation are also considered. PMID:26293351

  13. The forecaster's added value

    NASA Astrophysics Data System (ADS)

    Turco, M.; Milelli, M.

    2009-09-01

    skill scores of two competitive forecast. It is important to underline that the conclusions refer to the analysis of the Piemonte operational alert system, so they cannot be directly taken as universally true. But we think that some of the main lessons that can be derived from this study could be useful for the meteorological community. In details, the main conclusions are the following: - despite the overall improvement in global scale and the fact that the resolution of the limited area models has increased considerably over recent years, the QPF produced by the meteorological models involved in this study has not improved enough to allow its direct use, that is, the subjective HQPF continues to offer the best performance; - in the forecast process, the step where humans have the largest added value with respect to mathematical models, is the communication. In fact the human characterisation and communication of the forecast uncertainty to end users cannot be replaced by any computer code; - eventually, although there is no novelty in this study, we would like to show that the correct application of appropriated statistical techniques permits a better definition and quantification of the errors and, mostly important, allows a correct (unbiased) communication between forecasters and decision makers.

  14. Hydrogen Tunneling in Enzymes and Biomimetic Models

    SciTech Connect

    Layfield, Joshua P.; Hammes-Schiffer, Sharon

    2013-12-20

    Hydrogen transfer reactions play an important role throughout chemistry and biology. In general, hydrogen transfer reactions encompass proton and hydride transfer, which are associated with the transfer of a positively or negatively charged species, respectively, and proton-coupled electron transfer (PCET), which corresponds to the net transfer of one electron and one proton in the simplest case. Such PCET reactions can occur by either a sequential mechanism, in which the proton or electron transfers first, or a concerted mechanism, in which the electron and proton transfer in a single kinetic step with no stable intermediate. Furthermore, concerted PCET reactions can be subdivided into hydrogen atom transfer (HAT), which corresponds to the transfer of an electron and proton between the same donor and acceptor (i.e., the transfer of a predominantly neutral species), and electron-proton transfer (EPT), which corresponds to the transfer of an electron and proton between different donors and acceptors, possibly even in different directions. In all of these types of hydrogen transfer reactions, hydrogen tunneling could potentially play a signficant role. The theoretical development portion of this Review was supported by the National Science Foundation under CHE-10-57875. The biological portion of this Review was funded by NIH Grant No. GM056207. The biomimetic portion was supported as part of the Center for Molecular Electro-catalysis, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences.

  15. Hydrogen Tunneling in Enzymes and Biomimetic Models

    SciTech Connect

    Layfield, Joshua P.; Hammes-Schiffer, Sharon

    2014-04-09

    Hydrogen transfer reactions play an important role throughout chemistry and biology. In general, hydrogen transfer reactions encompass proton and hydride transfer, which are associated with the transfer of a positively or negatively charged species, respectively, and proton-coupled electron transfer (PCET), which corresponds to the net transfer of one electron and one proton in the simplest case. Such PCET reactions can occur by either a sequential mechanism, in which the proton or electron transfers first, or a concerted mechanism, in which the electron and proton transfer in a single kinetic step with no stable intermediate. Furthermore, concerted PCET reactions can be subdivided into hydrogen atom transfer (HAT), which corresponds to the transfer of an electron and proton between the same donor and acceptor (i.e., the transfer of a predominantly neutral species), and electron-proton transfer (EPT), which corresponds to the transfer of an electron and proton between different donors and acceptors, possibly even in different directions. In all of these types of hydrogen transfer reactions, hydrogen tunneling could potentially play a significant role. The biomimetic portion was supported as part of the Center for Molecular Electrocatalysis, an Energy Frontier Research Center funded by the U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences.

  16. Reactivity of coal in direct hydrogenation processes: Technical progress report, September-November 1987

    SciTech Connect

    Baldwin, R.M.; Miller, R.L.

    1987-01-01

    Research focused on two facets of the reactivity studies. First, a series of experimental runs aimed at investigation of the role of hydrogen in direct liquefaction were completed. A model compound system consisting of dibenzyl in aromatic (non-donor) or hydroaromatic (hydrogen donor) vehicles was hydrogenated to determine the effect of molecular hydrogen and hydrogen from donor molecules in the radical quenching and bond scission reactions. Special attention was paid to the role of hydrogen as an active bond cleavage agent. These data show the relative participation of hydrogen from both sources at conditions relevant to the reactivity data and provide support for the role of hydrogen acting directly to promote bond cleavage. Maintenance of a ''pool'' of hydrogen atoms was found to be of great importance in terms of promoting hydrogenolysis and hydrocracking reactions of dibenzyl. Five bituminous coals from the Argonne premium coal collection were liquefied at conditions similar to those employed in the model compound study. The general findings relative to the activity of molecular hydrogen determined from the model compound experiments were evidenced in the coal liquefaction data. Additionally, the presence of aliphatic hydrodgen in the coal itself was found to be a highly significant factor in determining the sensitivity of coal conversion to the presence of gas phase molecular hydrogen. 8 refs., 6 figs., 8 tabs.

  17. Characteristics, attitudes and personalities of AI donors.

    PubMed

    Nicholas, M K; Tyler, J P

    1983-03-01

    The first 50 men recruited to an artificial insemination by donor (AID) programme have been assessed for their attitudes and characteristics using a basic questionnaire and a standard well evaluated personality inventory. The results have shown that donors can be characterized as stable and moderately extroverted people who come from a wide range of occupations. Their marital and parental status had no particular relationship to their desire to donate and most of them volunteered for altruistic reasons, financial remuneration being a poor inducement. Most subjects lived within the close environs of the Westmead Centre and preferred to donate during normal working hours. The inconvenience of donating appeared to be the most important factor in considering new approaches to recruiting semen donors. PMID:6640474

  18. Mystery cloud of AD 536

    NASA Technical Reports Server (NTRS)

    Stothers, R. B.

    1984-01-01

    The possible cause of the densest and most persistent dry fog on record, which was observed in Europe and the Middle East during AD 536 and 537, is discussed. The fog's long duration toward the south and the high sulfuric acid signal detected in Greenland in ice cores dated around AD 540 support the theory that the fog was due to the explosion of the Rabaul volcano, the occurrence of which has been dated at about AD 540 by the radiocarbon method.

  19. Hydrogen bond dynamics in bulk alcohols

    SciTech Connect

    Shinokita, Keisuke; Cunha, Ana V.; Jansen, Thomas L. C.; Pshenichnikov, Maxim S.

    2015-06-07

    Hydrogen-bonded liquids play a significant role in numerous chemical and biological phenomena. In the past decade, impressive developments in multidimensional vibrational spectroscopy and combined molecular dynamics–quantum mechanical simulation have established many intriguing features of hydrogen bond dynamics in one of the fundamental solvents in nature, water. The next class of a hydrogen-bonded liquid—alcohols—has attracted much less attention. This is surprising given such important differences between water and alcohols as the imbalance between the number of hydrogen bonds, each molecule can accept (two) and donate (one) and the very presence of the hydrophobic group in alcohols. Here, we use polarization-resolved pump-probe and 2D infrared spectroscopy supported by extensive theoretical modeling to investigate hydrogen bond dynamics in methanol, ethanol, and isopropanol employing the OH stretching mode as a reporter. The sub-ps dynamics in alcohols are similar to those in water as they are determined by similar librational and hydrogen-bond stretch motions. However, lower density of hydrogen bond acceptors and donors in alcohols leads to the appearance of slow diffusion-controlled hydrogen bond exchange dynamics, which are essentially absent in water. We anticipate that the findings herein would have a potential impact on fundamental chemistry and biology as many processes in nature involve the interplay of hydrophobic and hydrophilic groups.

  20. Donor-recipient matching: myths and realities.

    PubMed

    Briceño, Javier; Ciria, Ruben; de la Mata, Manuel

    2013-04-01

    Liver transplant outcomes keep improving, with refinements of surgical technique, immunosuppression and post-transplant care. However, these excellent results and the limited number of organs available have led to an increasing number of potential recipients with end-stage liver disease worldwide. Deaths on waiting lists have led liver transplant teams maximize every organ offered and used in terms of pre and post-transplant benefit. Donor-recipient (D-R) matching could be defined as the technique to check D-R pairs adequately associated by the presence of the constituents of some patterns from donor and patient variables. D-R matching has been strongly analysed and policies in donor allocation have tried to maximize organ utilization whilst still protecting individual interests. However, D-R matching has been written through trial and error and the development of each new score has been followed by strong discrepancies and controversies. Current allocation systems are based on isolated or combined donor or recipient characteristics. This review intends to analyze current knowledge about D-R matching methods, focusing on three main categories: patient-based policies, donor-based policies and combined donor-recipient systems. All of them lay on three mainstays that support three different concepts of D-R matching: prioritarianism (favouring the worst-off), utilitarianism (maximising total benefit) and social benefit (cost-effectiveness). All of them, with their pros and cons, offer an exciting controversial topic to be discussed. All of them together define D-R matching today, turning into myth what we considered a reality in the past. PMID:23104164

  1. AdS Branes from Partial Breaking of Superconformal Symmetries

    SciTech Connect

    Ivanov, E.A.

    2005-10-01

    It is shown how the static-gauge world-volume superfield actions of diverse superbranes on the AdS{sub d+1} superbackgrounds can be systematically derived from nonlinear realizations of the appropriate AdS supersymmetries. The latter are treated as superconformal symmetries of flat Minkowski superspaces of the bosonic dimension d. Examples include the N = 1 AdS{sub 4} supermembrane, which is associated with the 1/2 partial breaking of the OSp(1|4) supersymmetry down to the N = 1, d = 3 Poincare supersymmetry, and the T-duality related L3-brane on AdS{sub 5} and scalar 3-brane on AdS{sub 5} x S{sup 1}, which are associated with two different patterns of 1/2 breaking of the SU(2, 2|1) supersymmetry. Another (closely related) topic is the AdS/CFT equivalence transformation. It maps the world-volume actions of the codimension-one AdS{sub d+1} (super)branes onto the actions of the appropriate Minkowski (super)conformal field theories in the dimension d.

  2. Risks for donors in uterus transplantation.

    PubMed

    Kisu, Iori; Mihara, Makoto; Banno, Kouji; Umene, Kiyoko; Araki, Jun; Hara, Hisako; Suganuma, Nobuhiko; Aoki, Daisuke

    2013-12-01

    Uterus transplantation (UTx) is an alternative to gestational surrogacy and adoption for patients with absolute uterine infertility. Studies have been conducted in animals, and UTx is now within the reach of clinical application in humans. Procedures in humans have been published, but many medical, ethical, and social problems and risks of UTx require discussion prior to widespread clinical application, from the perspectives of donors, recipients, families, and newborns. In this article, we summarize the burdens and risks of UTx, with a focus on donors who provide the uterus. PMID:23793471

  3. AdS5 backgrounds with 24 supersymmetries

    NASA Astrophysics Data System (ADS)

    Beck, S.; Gutowski, J.; Papadopoulos, G.

    2016-06-01

    We prove a non-existence theorem for smooth AdS 5 solutions with connected, compact without boundary internal space that preserve strictly 24 supersymmetries. In particular, we show that D = 11 supergravity does not admit such solutions, and that all such solutions of IIB supergravity are locally isometric to the AdS 5 × S 5 maximally supersymmetric background. Furthermore, we prove that (massive) IIA supergravity also does not admit such solutions, provided that the homogeneity conjecture for massive IIA supergravity is valid. In the context of AdS/CFT these results imply that if gravitational duals for strictly mathcal{N}=3 superconformal theories in 4-dimensions exist, they are either singular or their internal spaces are not compact.

  4. Entanglement temperature and perturbed AdS3 geometry

    NASA Astrophysics Data System (ADS)

    Levine, G. C.; Caravan, B.

    2016-06-01

    Generalizing the first law of thermodynamics, the increase in entropy density δ S (x ) of a conformal field theory (CFT) is proportional to the increase in energy density, δ E (x ) , of a subsystem divided by a spatially dependent entanglement temperature, TE(x ) , a fixed parameter determined by the geometry of the subsystem, crossing over to thermodynamic temperature at high temperatures. In this paper we derive a generalization of the thermodynamic Clausius relation, showing that deformations of the CFT by marginal operators are associated with spatial temperature variations, δ TE(x ) , and spatial energy correlations play the role of specific heat. Using AdS/CFT duality we develop a relationship between a perturbation in the local entanglement temperature of the CFT and the perturbation of the bulk AdS metric. In two dimensions, we demonstrate a method through which direct diagonalizations of the boundary quantum theory may be used to construct geometric perturbations of AdS3 .

  5. Water’s dual nature and its continuously changing hydrogen bonds

    NASA Astrophysics Data System (ADS)

    Henchman, Richard H.

    2016-09-01

    A model is proposed for liquid water that is a continuum between the ordered state with predominantly tetrahedral coordination, linear hydrogen bonds and activated dynamics and a disordered state with a continuous distribution of multiple coordinations, multiple types of hydrogen bond, and diffusive dynamics, similar to that of normal liquids. Central to water’s heterogeneous structure is the ability of hydrogen to donate to either one acceptor in a conventional linear hydrogen bond or to multiple acceptors as a furcated hydrogen. Linear hydrogen bonds are marked by slow, activated kinetics for hydrogen-bond switching to more crowded acceptors and sharp first peaks in the hydrogen-oxygen radial distribution function. Furcated hydrogens, equivalent to free, broken, dangling or distorted hydrogens, have barrierless, rapid kinetics and poorly defined first peaks in their hydrogen-oxygen radial distribution function. They involve the weakest donor in a local excess of donors, such that barrierless whole-molecule vibration rapidly swaps them between the linear and furcated forms. Despite the low number of furcated hydrogens and their transient existence, they are readily created in a single hydrogen-bond switch and free up the dynamics of numerous surrounding molecules, bringing about the disordered state. Hydrogens in the ordered state switch with activated dynamics to make the non-tetrahedral coordinations of the disordered state, which can also combine to make the ordered state. Consequently, the ordered and disordered states are both connected by diffusive dynamics and differentiated by activated dynamics, bringing about water’s continuous heterogeneity.

  6. Reactions of hydrogen with V-Cr-Ti alloys

    SciTech Connect

    DiStefano, J.R.; DeVan, J.H.; Chitwood, L.D.; Roehrig, D.H.

    1998-09-01

    In the absence of increases in oxygen concentration, additions of up to 400 ppm hydrogen to V-4 Cr-4 Ti did not result in significant embrittlement as determined by room temperature tensile tests. However, when hydrogen approached 700 ppm after exposure at 325 C, rapid embrittlement occurred. In this latter case, hydride formation is the presumed embrittlement cause. When oxygen was added during or prior to hydrogen exposure, synergistic effects led to significant embrittlement by 100 ppm hydrogen.

  7. A multidisciplinary program to educate and advocate for living donors.

    PubMed

    Sites, Anita K; Freeman, Jason R; Harper, Michael R; Waters, David B; Pruett, Timothy L

    2008-12-01

    Education is critical in decision making and the informed consent process in prospective living donors. Little has been written about how and what living donors should be taught. This article describes a multidisciplinary program for living donor education at the University of Virginia. The goals of the program are to impart information needed for prospective donors to make an informed decision and to independently evaluate donors' medical and psychosocial suitability. A partnership between the transplant department and an independent donor advocacy team establishes an environment conducive to education. By embracing independence, transparency, partnership, and advocacy, our program permits bidirectional education. This partnership facilitates unbiased understanding and appreciation of this education and considers each individual's unique circumstances when making informed decisions. Likewise, prospective donors educate the team about their circumstances, which helps the team safeguard the prospective donor and may enhance the safety of prospective donors and the perceived integrity of living organ donation. PMID:19186581

  8. 2509 living donor nephrectomies, morbidity and mortality, including the UK introduction of laparoscopic donor surgery.

    PubMed

    Hadjianastassiou, V G; Johnson, R J; Rudge, C J; Mamode, N

    2007-11-01

    The worldwide expansion of laparoscopic, at the expense of open, donor nephrectomy (DN) has been driven on the basis of faster convalescence for the donor. However, concerns have been expressed over the safety of the laparoscopic procedure. The UK Transplant National Registry collecting mandatory information on all living kidney donations in the country was analyzed for donations between November 2000 (start of living donor follow-up data reporting) to June 2006 to assess the safety of living DN, after the recent introduction of the laparoscopic procedure in the United Kingdom. Twenty-four transplant units reported data on 2509 donors (601 laparoscopic, 1800 open and 108 [4.3%] unspecified); 46.5% male; mean donor age: 46 years. There was one death 3 months postdischarge and a further five deaths beyond 1 year postdischarge. The mean length of stay was 1.5 days less for the laparoscopic procedure (p < 0.001). The risk of major morbidity for all donors was 4.9% (laparoscopic = 4.5%, open = 5.1%, p = 0.549). The overall rate of any morbidity was 14.3% (laparoscopic = 10.3%, open = 15.7%, p = 0.001). Living donation has remained a safe procedure in the UK during the learning curve of introduction of the laparoscopic procedure. The latter offers measurable advantages to the donor in terms of reduced length of stay and morbidity. PMID:17868058

  9. When 'sperm' becomes 'donor': transitions in parents' views of the sperm donor.

    PubMed

    Indekeu, Astrid; D'Hooghe, Thomas; Daniels, Ken R; Dierickx, Kris; Rober, Peter

    2014-12-01

    Abstract Little is known about recipients' views of their sperm donor. This study aimed to examine the possible transitions or consistencies in donor sperm recipients' (DSRs') view on the sperm donor over time. A longitudinal qualitative study of 19 Belgian heterosexual DSRs was undertaken. Interviews took place with both partners of the couple during pregnancy, at birth and 1.5-2 years after birth, and were analysed using a grounded theory approach. Recipients who intended to disclose exhibited a transition in their awareness of the donor from being of minimal importance to one who was increasingly seen as part of their family narrative. This was partly triggered by the offspring's life, remarks about resemblance and the socio-cultural context. The perceived position of the donor changed for most recipients from a threatening rival to a 'distractor'. This change was supported by the emerging father-child bond and the confidence that stemmed from it. These observations were applicable to those recipients who intended to disclose their donor conception; for those recipients who intended not to disclose, little or no transition was observed. This study describes and analyses the transitions and consistencies in recipients' views of the donor over different stages of the family life-cycle (pregnancy, birth, toddler stage) and could help the fertility clinics tailor their counselling to the specific stages of parenthood. PMID:24851674

  10. Use of the donor specific transfusion protocol in living-unrelated donor-recipient combinations.

    PubMed Central

    Sollinger, H W; Kalayoglu, M; Belzer, F O

    1986-01-01

    The scarcity of suitable cadaver or living-related kidneys remains the major problem in renal transplantation. The use of the donor-specific transfusion protocol (DST) has allowed for the expansion of the donor pool to one- and two-haplotype mismatched living-related donor-recipient combinations. This study deals with the use of DST in living-unrelated donor-recipient combinations (LURD). The following 34 LURD combinations were entered: husband to wife; wife to husband; friend to friend; stepfather; brother-in-law and sister-in-law. Donor-specific sensitization occurred in 21%. Actuarial graft survival at 4 years is 92.6%, and patient survival is 100%. It is concluded that this study indicates that the results with the use of LURDs equal the results with living-related donors and, therefore, it is suggested that the use of LURDs can be considered in situations when a medically and ethically acceptable unrelated donor is available. PMID:3530155

  11. Related hematopoietic cell donor care: is there a role for unrelated donor registries?

    PubMed

    Anthias, C; van Walraven, S M; Sørensen, B S; de Faveri, G N; Fechter, M; Cornish, J; Bacigalupo, A; Müller, C; Boo, M; Shaw, B E

    2015-05-01

    In almost half of allogeneic hematopoietic progenitor cell (HPC) transplants, a related donor (RD) is used, yet a lack of standardized guidelines means that their care is heterogeneous. Changes to regulatory standards aim to improve uniformity, but adherence to these regulations can prove logistically difficult for the transplant centers (TCs) managing RDs. Discussion has ensued around possible alternative models of related donor care and a session at the European Society for Blood and Marrow Transplantation (EBMT) annual meeting in 2013 debated the question of whether a role exists for unrelated donor registries in the management of 'related' donors. In this overview, we discuss the issues raised at this debate and the pros and cons of donor registry involvement in various aspects of RD management. By examining existing models of related donor care that have been adopted by members of the World Marrow Donor Association (WMDA), we look for ways to enhance and homogenize RD care, while also enabling transplant centers to meet standards required for mandatory accreditation. PMID:25730182

  12. ALTERNATIVE DONORS EXTEND TRANSPLANTATION FOR PATIENTS WITH LYMPHOMA WHO LACK AN HLA MATCHED DONOR

    PubMed Central

    Bachanova, Veronika; Burns, Linda J.; Wang, Tao; Carreras, Jeanette; Gale, Robert Peter; Wiernik, Peter H.; Ballen, Karen K.; Wirk, Baldeep; Munker, Reinhold; Rizzieri, David A.; Chen, Yi-Bin; Gibson, John; Akpek, Görgün; Costa, Luciano J.; Kamble, Rammurti T.; Aljurf, Mahmoud D.; Hsu, Jack W.; Cairo, Mitchell S.; Schouten, Harry C.; Bacher, Ulrike; Savani, Bipin N.; Wingard, John R.; Lazarus, Hillard M.; Laport, Ginna G.; Montoto, Silvia; Maloney, David G.; Smith, Sonali M.; Brunstein, Claudio; Saber, Wael

    2015-01-01

    Alternative donor transplantation is increasingly used for high risk lymphoma patients. We analyzed 1593 transplant recipients (2000 to 2010) and compared transplant outcomes in recipients of 8/8 allele human leukocyte antigen (HLA)-A, -B, -C, and DRB1 matched unrelated donors (MUD; n=1176), 7/8 allele HLA-matched unrelated donors (MMUD; n=275) and umbilical cord blood donors (1 or 2 units UCB; n=142). Adjusted 3-year non-relapse mortality of MMUD (44%) was higher as compared to MUD (35%; p=0.004), but similar to UCB recipients (37%; p=0.19), although UCB had lower rates of neutrophil and platelet recovery compared to unrelated donor groups. With a median follow-up of 55 months, 3-year adjusted cumulative incidence of relapse was lower after MMUD compared with MUD (25% vs 33%, p=0.003) but similar between UCB and MUD (30% vs 33%; p=0.48). In multivariate analysis UCB recipients had lower risks of acute and chronic graft versus host disease compared with adult donor groups (UCB vs MUD: HR=0.68, p=0.05; HR=0.35; p<0.001). Adjusted 3-year overall survival was comparable (43% MUD, 37% MMUD and 41% UCB). Data highlight that patients with lymphoma have acceptable survival after alternative donor transplantation. MMUD and UCB can expand the curative potential of allotransplant to patients who lack suitable HLA-matched sibling or MUD. PMID:25402415

  13. Donor Hemodynamics as a Predictor of Outcomes After Kidney Transplantation From Donors After Cardiac Death.

    PubMed

    Allen, M B; Billig, E; Reese, P P; Shults, J; Hasz, R; West, S; Abt, P L

    2016-01-01

    Donation after cardiac death is an important source of transplantable organs, but evidence suggests donor warm ischemia contributes to inferior outcomes. Attempts to predict recipient outcome using donor hemodynamic measurements have not yielded statistically significant results. We evaluated novel measures of donor hemodynamics as predictors of delayed graft function and graft failure in a cohort of 1050 kidneys from 566 donors. Hemodynamics were described using regression line slopes, areas under the curve, and time beyond thresholds for systolic blood pressure, oxygen saturation, and shock index (heart rate divided by systolic blood pressure). A logistic generalized estimation equation model showed that area under the curve for systolic blood pressure was predictive of delayed graft function (above median: odds ratio 1.42, 95% confidence interval [CI] 1.06-1.90). Multivariable Cox regression demonstrated that slope of oxygen saturation during the first 10 minutes after extubation was associated with graft failure (below median: hazard ratio 1.30, 95% CI 1.03-1.64), with 5-year graft survival of 70.0% (95%CI 64.5%-74.8%) for donors above the median versus 61.4% (95%CI 55.5%-66.7%) for those below the median. Among older donors, increased shock index slope was associated with increased hazard of graft failure. Validation of these findings is necessary to determine the utility of characterizing donor warm ischemia to predict recipient outcome. PMID:26361242

  14. Tissue banking: relationship with blood donor and organ donor card status.

    PubMed

    McKenzie, Kenneth D; Fitzpatrick, Patricia E; Sheehan, John D

    2012-01-01

    Understanding the relationships among altruistic health acts may serve to aid therapeutic research advances. In this paper, we report on the links between two such behaviours-donating blood and carrying an organ donor card-and willingness to donate urological tissue to a tissue bank. Reasons for the differential willingness to do so are examined in this paper. A systematic sample of 259 new and returning attendees at a tertiary urology referral clinic in Ireland completed a self-report questionnaire in an outpatient setting. In addition to demographic details, details of known diagnosis of malignancy and family history of cancer; attitudes to tissue donation for research purposes were gauged using a 5-point Likert scale. Both blood donors and organ donor card carriers were more likely to be willing to donate tissue for research purposes. Blood donors were more likely want to know their overall results in comparison to nonblood donors and want their samples to be used for nonprofit research. Our hypothesis that being a blood donor would be a better predictor to donate urological tissue than being an organ donor card carrier borne out by the trends reported above. PMID:22567418

  15. Enhancement by dimethyl myleran of donor type chimerism in murine recipients of bone marrow allografts

    SciTech Connect

    Lapidot, T.; Terenzi, A.; Singer, T.S.; Salomon, O.; Reisner, Y. )

    1989-05-15

    A major problem in using murine models for studies of bone marrow allograft rejection in leukemia patients is the narrow margin in which graft rejection can be analyzed. In mice irradiated with greater than 9 Gy total body irradiation (TBI) rejection is minimal, whereas after administration of 8 Gy TBI, which spares a significant number of clonable T cells, a substantial frequency of host stem cells can also be detected. In current murine models, unlike in humans, bone marrow allograft rejection is generally associated with full autologous hematopoietic reconstitution. In the present study, we investigated the effect of the myeloablative drug dimethyl myleran (DMM) on chimerism status following transplantation of T cell-depleted allogenic bone marrow (using C57BL/6 donors and C3H/HeJ recipients, conditioned with 8 Gy TBI). Donor type chimerism 1 to 2 months post-transplant of 1 to 3 x 10(6) bone marrow cells was markedly enhanced by using DMM one day after TBI and prior to transplantation. Conditioning with cyclophosphamide instead of DMM, in combination with 8 Gy TBI, did not enhance engraftment of donor type cells. Artificial reconstitution of T cells, after conditioning with TBI plus DMM, by adding mature thymocytes, or presensitization with irradiated donor type spleen cells 1 week before TBI and DMM, led to strong graft rejection and consequently to severe anemia. The anti-donor responses in these models were proportional to the number of added T cells and to the number of cells used for presensitization, and they could be neutralized by increasing the bone marrow inoculum.

  16. General model of electrochemical hydrogen absorption into metals

    SciTech Connect

    Lasia, A.; Gregoire, D.

    1995-10-01

    A general model for the hydrogen adsorption and hydrogen absorption into metals has been proposed. It includes reactions of hydrogen evolution M+H{sub 2}O+e=MH{sub ads}+OH{sup {minus}}; MH{sub ads}+H{sub 2}O+e=M+H{sub 2}+OH{sup {minus}}; and 2MH{sub ads}+2M+H{sub 2}; hydrogen absorption MH{sub ads}+MH{sub abs}; and hydrogen diffusion into metal. This problem leads to a system of differential equations which was solved using the differential algebraic equations method. Solutions were obtained for constant potential and constant current charging/discharging in the case of semi-infinite and finite length diffusion for planar, spherical, and cylindrical diffusion. Numerical solutions give new information about the reaction mechanism and may be useful in the determination of the kinetics of these processes.

  17. Storing Hydrogen

    SciTech Connect

    Kim, Hyun Jeong; Karkamkar, Abhijeet J.; Autrey, Thomas; Chupas, Peter; Proffen, Thomas E.

    2010-05-31

    Researchers have been studying mesoporous materials for almost two decades with a view to using them as hosts for small molecules and scaffolds for molding organic compounds into new hybrid materials and nanoparticles. Their use as potential storage systems for large quantities of hydrogen has also been mooted. Such systems that might hold large quantities of hydrogen safely and in a very compact volume would have enormous potential for powering fuel cell vehicles, for instance. A sponge-like form of silicon dioxide, the stuff of sand particles and computer chips, can soak up and store other compounds including hydrogen. Studies carried out at the XOR/BESSRC 11-ID-B beamline at the APS have revealed that the nanoscopic properties of the hydrogenrich compound ammonia borane help it store hydrogen more efficiently than usual. The material may have potential for addressing the storage issues associated with a future hydrogen economy. Pacific Northwest National Laboratory is operated by Battelle for the US Department of Energy.

  18. Hydrogen storage material and process using graphite additive with metal-doped complex hydrides

    DOEpatents

    Zidan, Ragaiy; Ritter, James A.; Ebner, Armin D.; Wang, Jun; Holland, Charles E.

    2008-06-10

    A hydrogen storage material having improved hydrogen absorbtion and desorption kinetics is provided by adding graphite to a complex hydride such as a metal-doped alanate, i.e., NaAlH.sub.4. The incorporation of graphite into the complex hydride significantly enhances the rate of hydrogen absorbtion and desorption and lowers the desorption temperature needed to release stored hydrogen.

  19. Lorentzian AdS geometries, wormholes, and holography

    SciTech Connect

    Arias, Raul E.; Silva, Guillermo A.; Botta Cantcheff, Marcelo

    2011-03-15

    We investigate the structure of two-point functions for the quantum field theory dual to an asymptotically Lorentzian Anti de Sitter (AdS) wormhole. The bulk geometry is a solution of five-dimensional second-order Einstein-Gauss-Bonnet gravity and causally connects two asymptotically AdS spacetimes. We revisit the Gubser-Klebanov-Polyakov-Witten prescription for computing two-point correlation functions for dual quantum field theories operators O in Lorentzian signature and we propose to express the bulk fields in terms of the independent boundary values {phi}{sub 0}{sup {+-}} at each of the two asymptotic AdS regions; along the way we exhibit how the ambiguity of normalizable modes in the bulk, related to initial and final states, show up in the computations. The independent boundary values are interpreted as sources for dual operators O{sup {+-}} and we argue that, apart from the possibility of entanglement, there exists a coupling between the degrees of freedom living at each boundary. The AdS{sub 1+1} geometry is also discussed in view of its similar boundary structure. Based on the analysis, we propose a very simple geometric criterion to distinguish coupling from entanglement effects among two sets of degrees of freedom associated with each of the disconnected parts of the boundary.

  20. Self-dual warped AdS3 black holes

    NASA Astrophysics Data System (ADS)

    Chen, Bin; Ning, Bo

    2010-12-01

    We study a new class of solutions of three-dimensional topological massive gravity. These solutions can be taken as nonextremal black holes, with their extremal counterparts being discrete quotients of spacelike warped AdS3 along the U(1)L isometry. We study the thermodynamics of these black holes and show that the first law is satisfied. We also show that for consistent boundary conditions, the asymptotic symmetry generators form only one copy of the Virasoro algebra with central charge cL=(4νℓ)/(G(ν2+3)), with which the Cardy formula reproduces the black hole entropy. We compute the real-time correlators of scalar perturbations and find a perfect match with the dual conformal field theory (CFT) predictions. Our study provides a novel example of warped AdS/CFT correspondence: the self-dual warped AdS3 black hole is dual to a CFT with nonvanishing left central charge. Moreover, our investigation suggests that the quantum topological massive gravity asymptotic to the same spacelike warped AdS3 in different consistent ways may be dual to different two-dimensional CFTs.

  1. Compliance with donor age recommendations in oocyte donor recruitment advertisements in the USA.

    PubMed

    Alberta, Hillary B; Berry, Roberta M; Levine, Aaron D

    2013-04-01

    IVF using donated oocytes offers benefits to many infertile patients, yet the technique also raises a number of ethical concerns, including worries about potential physical and psychological risks to oocyte donors. In the USA, oversight of oocyte donation consists of a combination of federal and state regulations and self-regulatory guidelines promulgated by the American Society for Reproductive Medicine. This study assesses compliance with one of these self-regulatory guidelines - specifically, ASRM's preferred minimum age for donors of 21. To assess compliance, 539 oocyte donor recruitment advertisements from two recruitment channels (Craigslist and college newspapers) were collected and evaluated. Of these, 61% in the Craigslist dataset and 43% in the college newspaper dataset listed minimum ages between 18 and 20, which is inconsistent with ASRM's preferred minimum age recommendation of 21. Advertisements placed by oocyte donor recruitment agencies were more likely than advertisements placed by clinics to specify minimum ages between 18 and 20. These results indicate that ASRM should evaluate and consider revising its donor age guidelines. IVF using donated human eggs can help many patients who have difficulty having children. However, the technique also raises ethical concerns, including concerns about potential physical and psychological harms to egg donors. In the USA, oversight of egg donation relies on a combination of federal and state regulation and professional self-regulation. Governmental regulations address only limited aspects of egg donation, such as the potential spread of infectious diseases and the reporting of success rates, leaving voluntary guidelines developed by an association of medical professionals to address most issues, including ethical concerns raised by the practice. One of these voluntary guidelines recommends that egg donors should be at least 21 years of age. In this article, we analysed 539 egg donor recruitment advertisements

  2. The Summer of Hydrogen

    NASA Technical Reports Server (NTRS)

    Weber, Philip

    2008-01-01

    Ground crew veterans at Kennedy Space Center still talk about what they call "the summer of hydrogen"-the long, frustrating months in 1990 when the shuttle fleet was grounded by an elusive hydrogen leak that foiled our efforts to fill the orbiter's external fuel tank. Columbia (STS-35) was on Launch Pad A for a scheduled May 30 launch when we discovered the hydrogen leak during - tanking. The external fuel tank is loaded through the orbiter. Liquid hydrogen flows through a 17-inch umbilical between the orbiter and the tank. During fueling, we purge the aft fuselage with gaseous nitrogen to reduce the risk of fire, and we have a leak-detection system in the mobile launch platform, which samples (via tygon tubing) the atmosphere in and around the vehicle, drawing it down to a mass spectrometer that analyzes its composition. When we progressed to the stage of tanking where liquid hydrogen flows through the vehicle, the concentration of hydrogen approached four percent-the limit above which it would be dangerously flammable. We had a leak. We did everything we could think of to find it, and the contractor who supplied the flight hardware was there every day, working alongside us. We did tanking tests, which involved instrumenting the suspected leak sources, and cryo-loaded the external tank to try to isolate precisely where the leak originated. We switched out umbilicals; we replaced the seals between the umbilical and the orbiter. We inspected the seals microscopically and found no flaws. We replaced the recirculation pumps, and we found and replaced a damaged teflon seal in a main propulsion system detent cover, which holds the prevalve-the main valve supplying hydrogen to Space Shuttle Main Engine 3 -in the open position. The seal passed leak tests at ambient temperature but leaked when cryogenic temperatures were applied. We added new leak sensors-up to twenty at a time and tried to be methodical in our placements to narrow down the possible sources of the problem

  3. Hydrogen program overview

    SciTech Connect

    Gronich, S.

    1997-12-31

    This paper consists of viewgraphs which summarize the following: Hydrogen program structure; Goals for hydrogen production research; Goals for hydrogen storage and utilization research; Technology validation; DOE technology validation activities supporting hydrogen pathways; Near-term opportunities for hydrogen; Market for hydrogen; and List of solicitation awards. It is concluded that a full transition toward a hydrogen economy can begin in the next decade.

  4. Hydrogen local vibrational modes in semiconductors

    SciTech Connect

    McCluskey, M D

    1997-06-01

    Following, a review of experimental techniques, theory, and previous work, the results of local vibrational mode (LVM) spectroscopy on hydrogen-related complexes in several different semiconductors are discussed. Hydrogen is introduced either by annealing in a hydrogen ambient. exposure to a hydrogen plasma, or during growth. The hydrogen passivates donors and acceptors in semiconductors, forming neutral complexes. When deuterium is substituted for hydrogen. the frequency of the LVM decreases by approximately the square root of two. By varying the temperature and pressure of the samples, the microscopic structures of hydrogen-related complexes are determined. For group II acceptor-hydrogen complexes in GaAs, InP, and GaP, hydrogen binds to the host anion in a bond-centered orientation, along the [111] direction, adjacent to the acceptor. The temperature dependent shift of the LVMs are proportional to the lattice thermal energy U(T), a consequence of anharmonic coupling between the LVM and acoustical phonons. In the wide band gap semiconductor ZnSe, epilayers grown by metalorganic chemical vapor phase epitaxy (MOCVD) and doped with As form As-H complexes. The hydrogen assumes a bond-centered orientation, adjacent to a host Zn. In AlSb, the DX centers Se and Te are passivated by hydrogen. The second, third, and fourth harmonics of the wag modes are observed. Although the Se-D complex has only one stretch mode, the Se-H stretch mode splits into three peaks. The anomalous splitting is explained by a new interaction between the stretch LVM and multi-phonon modes of the lattice. As the temperature or pressure is varied, and anti-crossing is observed between LVM and phonon modes.

  5. Solid state and solution studies of lithium tris(n-butyl)magnesiates stabilised by Lewis donors.

    PubMed

    Zaragoza-Calero, Silvia; Francos, Javier; Kennedy, Alan R; O'Hara, Charles T

    2015-04-28

    Several Lewis base adducts of the synthetically important lithium tris(n-butyl)magnesiate LiMg((n)Bu)3 have been prepared and structurally characterised. The complexes were prepared by a co-complexation approach i.e., by combining the monometallic (n)BuLi and (n)Bu2Mg reagents in hydrocarbon solution before adding a molar equivalent of a donor molecule (a bidentate amine, tridentate amine or cyclic ether). The lithium magnesiates all adopt variants of the "Weiss motif" structure, i.e., contacted ion pair dimers with a linear arrangement and metals connected by butyl anions, where tetrahedral magnesium ions are in the central positions and the lithiums occupy the outer region, solvated by a neutral Lewis donor [(donor)Li(μ-(n)Bu)2Mg(μ-(n)Bu)2Mg(μ-(n)Bu)2Li(donor)]. When TMPDA, PMDETA or (R,R)-TMCDA [TMPDA = N,N,N'N'-tetramethylpropanediamine; PMDETA = N,N,N',N'',N''-pentamethyldiethylenetriamine; and (R,R)-TMCDA = (R,R)-N,N,N',N'-tetramethylcyclohexane-1,2-diamine], are employed, dimeric tetranuclear lithium magnesiates are produced. Due to the tridentate nature of the ligand, the PMDETA-containing structure (2) has an unusual 'open'-motif. When TMEDA (TMEDA = N,N,N',N'-tetramethylethylenediamine) is employed, a n-butoxide-containing complex [(TMEDA)Li(μ-(n)Bu)(μ-O(n)Bu)Mg2((n)Bu)2(μ-(n)Bu)(μ-O(n)Bu)Li(donor)] has been serendipitously prepared and adopts a ladder conformation which is commonly observed in lithium amide chemistry. This complex has also been prepared using a rational methodology. When 1,4-dioxane is employed, the donor stitches together a polymeric array of tetranuclear dimeric units (6). The hydrocarbon solution structures of the compounds have been characterised by (1)H, (7)Li, (13)C NMR spectroscopy; 2 has been studied by variable temperature and DOSY NMR. PMID:25791270

  6. DONOR-ACCEPTOR INTERACTIONS OF NITROGEN*

    PubMed Central

    Kimura, J. E.; Szent-Györgyi, A.

    1969-01-01

    The nitrogen atoms of organic molecules readily enter into donor-acceptor interactions, giving off an electron from their lone pair. Under favorable conditions the acceptor can form free radicals. S and O atoms behave likewise but less intensely. PMID:4306047

  7. Electron Donor Acceptor Interactions. Final Progress Report

    SciTech Connect

    2002-08-16

    The Gordon Research Conference (GRC) on Electron Donor Acceptor Interactions was held at Salve Regina University, Newport, Rhode Island, 8/11-16/02. Emphasis was placed on current unpublished research and discussion of the future target areas in this field.

  8. Case 1: chronic infected donor site.

    PubMed

    2016-03-01

    Following a coronary bypass surgery, a vein donor site became infected and failed to heal despite use of antibiotics and a variety of topical treatments. Octenilin Wound Gel not only helped to promote healing, but also increased the patient's ability to tolerate dressing changes. PMID:26949845

  9. Electron shuttling in phosphorus donor qubit systems

    NASA Astrophysics Data System (ADS)

    Jacobson, N. Tobias; Gamble, John King; Nielsen, Erik; Muller, Richard P.; Witzel, Wayne M.; Montano, Ines; Carroll, Malcolm S.

    2014-03-01

    Phosphorus donors in silicon are a promising qubit architecture, due in large part to their long nuclear coherence times and the recent development of atomically precise fabrication methods. Here, we investigate issues related to implementing qubits with phosphorus donors in silicon, employing an effective mass theory that non-phenomenologically takes into account inter-valley coupling. We estimate the significant sources of decoherence and control errors in this system to compute the fidelity of primitive gates and gate timescales. We include the effects of valley repopulation during the process of shuttling an electron between a donor and nearby interface or between neighboring donors, evaluating the control requirements for ensuring adiabaticity with respect to the valley sector. This work was supported in part by the LDRD program at Sandia National Labs, a multi-program laboratory managed and operated by Sandia Corp, a wholly owned subsidiary of Lockheed Martin Corp, for the U.S. DOE NNSA under contract DE-AC04-94AL85000.

  10. Warped AdS3/dipole-CFT duality

    NASA Astrophysics Data System (ADS)

    Song, Wei; Strominger, Andrew

    2012-05-01

    String theory contains solutions with {{SL}}( {{2},{R}} ){{R}} × {{U}}{( {1} )_L} -invariant warped AdS3 (WAdS3) factors arising as continuous deformations of ordinary AdS3 factors. We propose that some of these are holographically dual to the IR limits of nonlocal dipole-deformed 2D D-brane gauge theories, referred to as "dipole CFTs". Neither the bulk nor boundary theories are currently well-understood, and consequences of the proposed duality for both sides is investigated. The bulk entropy-area law suggests that dipole CFTs have (at large N) a high-energy density of states which does not depend on the deformation parameter. Putting the boundary theory on a spatial circle leads to closed timelike curves in the bulk, suggesting a relation of the latter to dipole-type nonlocality.

  11. New boundary conditions for AdS3

    NASA Astrophysics Data System (ADS)

    Compère, Geoffrey; Song, Wei; Strominger, Andrew

    2013-05-01

    New chiral boundary conditions are found for quantum gravity with matter on AdS3. The associated asymptotic symmetry group is generated by a single right-moving U(1) Kac-Moody-Virasoro algebra with {c_R}={3ℓ}/2G . The Kac-Moody zero mode generates global left-moving translations and equals, for a BTZ black hole, the sum of the total mass and spin. The level is positive about the global vacuum and negative in the black hole sector, corresponding to ergosphere formation. Realizations arising in Chern-Simons gravity and string theory are analyzed. The new boundary conditions are shown to naturally arise for warped AdS3 in the limit that the warp parameter is taken to zero.

  12. Observing quantum gravity in asymptotically AdS space

    NASA Astrophysics Data System (ADS)

    Emelyanov, Slava

    2015-12-01

    The question is studied of whether an observer can discover quantum gravity in the semiclassical regime. It is shown that it is indeed possible to probe a certain quantum gravity effect by employing an appropriately designed detector. The effect is related to the possibility of having topologically inequivalent geometries in the path-integral approach at the same time. A conformal field theory (CFT) state which is expected to describe the eternal anti-de Sitter (AdS) black hole in the large-N limit is discussed. It is argued under certain assumptions that the black hole boundary should be merely a patch of the entire AdS boundary. This leads then to a conclusion that that CFT state is the ordinary CFT vacuum restricted to that patch. If existent, the bulk CFT operators can behave as the ordinary semiclassical quantum field theory in the large-N limit in the weak sense.

  13. Semiclassical Virasoro blocks from AdS3 gravity

    NASA Astrophysics Data System (ADS)

    Hijano, Eliot; Kraus, Per; Perlmutter, Eric; Snively, River

    2015-12-01

    We present a unified framework for the holographic computation of Virasoro conformal blocks at large central charge. In particular, we provide bulk constructions that correctly reproduce all semiclassical Virasoro blocks that are known explicitly from conformal field theory computations. The results revolve around the use of geodesic Witten diagrams, recently introduced in [1], evaluated in locally AdS3 geometries generated by backreaction of heavy operators. We also provide an alternative computation of the heavy-light semiclassical block — in which two external operators become parametrically heavy — as a certain scattering process involving higher spin gauge fields in AdS3; this approach highlights the chiral nature of Virasoro blocks. These techniques may be systematically extended to compute corrections to these blocks and to interpolate amongst the different semiclassical regimes.

  14. Hepatitis C virus infection in the asymptomatic British blood donor.

    PubMed

    Mutimer, D J; Harrison, R F; O'Donnell, K B; Shaw, J; Martin, B A; Atrah, H; Ala, F A; Skidmore, S; Hubscher, S G; Neuberger, J M

    1995-01-01

    Blood donor screening for hepatitis C virus (HCV) antibodies is now routine. Most blood transfusion services recommend that seropositive donors are referred for further investigation. Southern European studies suggest that many asymptomatic seropositive donors have clinically significant liver disease. Seropositive donors in areas of high prevalence may not, however, be representative of British donors. We have prospectively examined the prevalence and severity of HCV infection in a British volunteer blood donor population. During a 14 month period, only 0.35% (999/287,332) of all donors in the West Midlands were anti-HCV (screening assay) positive. Only 5% (52/999) of these were confirmed true seropositive. Nearly 80% (41/52) of seropositive donors were referred to the Queen Elizabeth Hospital Liver Unit for further investigation. Most underwent complete investigation, including liver biopsy. Forty of forty-one donors had biochemical, histological, or virological evidence of persistent viral infection. Histological changes were generally mild and none was cirrhotic. Covertly infected patients had less severe disease than those with an overt risk factor for HCV exposure. In the British Midlands, the prevalence of blood donor seropositivity is low. In contrast with seropositive Southern European donors, the British donor is more likely to belong to an at-risk group for parenteral exposure and is less likely to have severe histological changes. This study highlights the importance of developing locally relevant guidelines for the counselling and investigation of anti-HCV-positive blood donors. PMID:7493294

  15. Achieving donor repetition and motivation by block leaders among current blood donors.

    PubMed

    Martín-Santana, Josefa D; Beerli-Palacio, Asunción

    2012-12-01

    This paper presents an explicative model on the recommendation of donating blood made to relatives and friends by current donors. This model establishes satisfaction and intention to return as direct antecedents, and the quality perceived in the donation process and the existence of inhibitors as indirect antecedents. The results show that (1) the perceived quality has a positive influence on satisfaction and intention to return; (2) the intention to donate again depends positively on satisfaction, but negatively on the existence of internal and external inhibitors; and lastly (3) the recommendation to donate depends on donor satisfaction and their intention to return to donate, this being the most influential factor. At the same time, we contrasted how the model does not vary, whether it is a first-time donor or a repeat donor. PMID:22683233

  16. The personality and motivation of semen donors: a comparison with oocyte donors.

    PubMed

    Schover, L R; Rothmann, S A; Collins, R L

    1992-04-01

    Seventeen consecutively recruited candidates for semen donation were evaluated by a psychologist with testing and a structured interview. Most men (71%) were motivated by financial compensation. Only 29% would donate semen if records were open to potential offspring. Fifty-nine per cent of the men were rated as excellent candidates from a psychological perspective and 35% were rated as acceptable with slight reservations. One was excluded as a donor. Psychological testing revealed mildly abnormal subscale scores for 35% of donors. Forty-seven per cent had histories of minor depressive or anxiety episodes and 35% had had periods of heavy alcohol use. Compared to oocyte donors at the same institution, the men were less altruistic, more affluent, and more likely to have abused alcohol. Women had more traumatic family and reproductive histories. Psychological evaluation can be a valuable tool in gamete donor selection. PMID:1522206

  17. Hydrogen Embrittlement Susceptibility and Hydrogen-Induced Additive Stress of 7050 Aluminum Alloy Under Various Aging States

    NASA Astrophysics Data System (ADS)

    Qi, W. J.; Song, R. G.; Qi, X.; Li, H.; Wang, Z. X.; Wang, C.; Jin, J. R.

    2015-09-01

    Hydrogen embrittlement susceptibility of 7050 aluminum alloy under various aging states has been investigated by means of cathodic hydrogen permeation, slow strain rate test, hydrogen determinator, x-ray diffraction, and scanning electron microscope, and effect of hydrogen on atomic binding force of charged alloy has been calculated by free electron theory in this paper. Simultaneously, hydrogen-induced additive stress (σad) of 7050 aluminum alloy hydrogen charged with different current densities under various aging states have been investigated by flowing stress differential method. The results showed that hydrogen concentration of examined alloy increased with increasing charging time or current density under the same aging state. Hydrogen segregation occurred at grain boundaries which enlarged the crystal lattice constant, meanwhile, it reduced the average bonding energy and interatomic bonding force of the grain boundary atoms, thus resulting in hydrogen embrittlement; moreover, σad of 7050 aluminum alloy increased linearly with increasing hydrogen concentration under the same aging state, i.e., under aged: σad = -1.61 + 9.93 × 105 C H, peak aged: σad = -1.55 + 9.67 × 105 C H, over aged: σad = -0.16 + 9.35 × 105 C H, correspondingly, σad increased the susceptibility to hydrogen embrittlement ( I HE) further. Under the same charging condition, aging states had a great influence on σad and I HE, the under-aged state alloy was of the highest, the over-aged state alloy was of the lowest, and peak-aged was in the middle.

  18. Treponema pallidum hemagglutination assay seroreactivity among healthy Indian donors and its association with other transfusion transmitted diseases

    PubMed Central

    Pahuja, Sangeeta; Gupta, Santosh Kumar; Pujani, Mukta; Jain, Manjula

    2014-01-01

    seropositivity correlated with higher HIV and HCV seropositivity and the same correlation has been observed by several other studies also. In view of these observations, we propose that testing for syphilis by more sensitive and specific treponemal markers like TPHA rather than VDRL, rapid plasma reagin tests; as TPHA also has the added advantage of picking up all the high risk donors, whereas, VDRL picks up only currently infected donors. Moreover, TPHA should be continued as a marker of high risk behavior especially in high prevalence areas like India where we don’t have universal access to markers like nucleic acid amplification technique. PMID:25161350

  19. Alday-Maldacena Duality and AdS Plateau Problem

    NASA Astrophysics Data System (ADS)

    Morozov, A.

    A short summary of approximate approach to the study of minimal surfaces in AdS, based on solving Nambu-Goto equations iteratively. Today, after partial denunciation of the BDS conjecture, this looks like the only constructive approach to understanding the ways of its possible modification and thus to saving the Alday-Maldacena duality. Numerous open technical problems are explicitly formulated throughout the text.

  20. Hydrogenation of coal liquid utilizing a metal carbonyl catalyst

    DOEpatents

    Feder, Harold M.; Rathke, Jerome W.

    1979-01-01

    Coal liquid having a dissolved transition metal, catalyst as a carbonyl complex such as Co.sub.2 (CO.sub.8) is hydrogenated with hydrogen gas or a hydrogen donor. A dissociating solvent contacts the coal liquid during hydrogenation to form an immiscible liquid mixture at a high carbon monoxide pressure. The dissociating solvent, e.g. ethylene glycol, is of moderate coordinating ability, while sufficiently polar to solvate the transition metal as a complex cation along with a transition metal, carbonyl anion in solution at a decreased carbon monoxide pressure. The carbon monoxide pressure is reduced and the liquids are separated to recover the hydrogenated coal liquid as product. The dissociating solvent with the catalyst in ionized form is recycled to the hydrogenation step at the elevated carbon monoxide pressure for reforming the catalyst complex within fresh coal liquid.

  1. Donor liver dysfunction: application of a new scoring system to identify the marginal donor.

    PubMed

    Ferraz-Neto, B H; Zurstrassen, M P V C; Hidalgo, R; Fonseca, L E P; Motta, T D B; Pandullo, F L; Rezende, M B; Meira-Filho, S P; Sá, J R; Afonso, R C

    2007-10-01

    Livers from marginal donors are increasingly used for transplantation due to the shortage of donor organs. The definition of a marginal donor remains unclear; prediction of organ function is a challenge. In the literature the use of steatotic livers has been associated with poor liver function or even primary dysfunction of the allograft. Tekin et al created a scoring system that classifies a donor as marginal or nonmarginal, using a mathematical model based on donor age and steatosis degree. The aims of this study were to apply the Tekin method to identify marginal and nonmarginal donors and evaluate the influence of the cold ischemia time (CIT) on allograft evolution. We retrospectively reviewed deceased donor liver transplantations performed from October 1995 to March 2006, namely, 177 adult liver transplantations in 163 patients. Fifty-five were excluded due to retransplantation (14) or insufficient data (41). Donor age and macrovesicular steatosis were evaluated according to the mathematical formula proposed by Tekin et al, classifying the donors as marginal versus nonmarginal. The authors also analyzed the CIT, 3-month mortality, and development of primary nonfunction or primary dysfunction. The median donor age was 38.9 years (range, 6-71). The postreperfusion biopsy specimen showed moderate to intense steatosis (>30%) in 14.75% of specimens, with no steatosis or mild steatosis in 85.25%. Sixty-one grafts (50%) developed primary graft dysfunction (PGD): 10 grafts, with primary nonfunction (PNF); and 51 with initial poor function (IPF). Using the criteria provided by Tekin et al, we obtained 41 marginal and 81 nonmarginal allografts. The marginal group showed 61.9% PGD, compared with 59.2% of PGD by the nonmarginal group. The CIT was greater than 12 hours in 5 marginal group transplants and 4 PGD cases (80%). Of the nonmarginal allografts, the CIT was greater than 12 hours in 29.6%, with 75% PGD. The 3-month graft survival rate was 80% in the marginal group

  2. On information loss in AdS3/CFT2

    NASA Astrophysics Data System (ADS)

    Fitzpatrick, A. Liam; Kaplan, Jared; Li, Daliang; Wang, Junpu

    2016-05-01

    We discuss information loss from black hole physics in AdS3, focusing on two sharp signatures infecting CFT2 correlators at large central charge c: `forbidden singularities' arising from Euclidean-time periodicity due to the effective Hawking temperature, and late-time exponential decay in the Lorentzian region. We study an infinite class of examples where forbidden singularities can be resolved by non-perturbative effects at finite c, and we show that the resolution has certain universal features that also apply in the general case. Analytically continuing to the Lorentzian regime, we find that the non-perturbative effects that resolve forbidden singularities qualitatively change the behavior of correlators at times t ˜ S BH , the black hole entropy. This may resolve the exponential decay of correlators at late times in black hole backgrounds. By Borel resumming the 1 /c expansion of exact examples, we explicitly identify `information-restoring' effects from heavy states that should correspond to classical solutions in AdS3. Our results suggest a line of inquiry towards a more precise formulation of the gravitational path integral in AdS3.

  3. Supersymmetric giant graviton solutions in AdS3

    NASA Astrophysics Data System (ADS)

    Mandal, Gautam; Raju, Suvrat; Smedbäck, Mikael

    2008-02-01

    We parametrize all classical probe brane configurations that preserve four supersymmetries in (a) the extremal D1-D5 geometry, (b) the extremal D1-D5-P geometry, (c) the smooth D1-D5 solutions proposed by Lunin and Mathur, and (d) global AdS3×S3×T4/K3. These configurations consist of D1 branes, D5 branes, and bound states of D5 and D1 branes with the property that a particular Killing vector is tangent to the brane world volume at each point. We show that the supersymmetric sector of the D5-brane world volume theory may be analyzed in an effective 1+1 dimensional framework that places it on the same footing as D1 branes. In global AdS and the corresponding Lunin-Mathur solution, the solutions we describe are “bound” to the center of AdS for generic parameters and cannot escape to infinity. We show that these probes only exist on the submanifold of moduli space where the background BNS field and theta angle vanish. We quantize these probes in the near-horizon region of the extremal D1-D5 geometry and obtain the theory of long strings discussed by Seiberg and Witten.

  4. Molecular assembly of amino acid interlinked, topologically symmetric, π-complementary donor-acceptor-donor triads.

    PubMed

    Avinash, M B; Sandeepa, K V; Govindaraju, T

    2013-01-01

    Amino acid interlinked pyrene and naphthalenediimide (NDI) based novel donor-acceptor-donor (D-A-D) triads are designed to exploit their topological symmetry and complementary π-character for facile charge-transfer complexation. Consequently, free-floating high-aspect-ratio supercoiled nanofibres and hierarchical helical bundles of triads are realized by modulating the chemical functionality of interlinking amino acids. PMID:23946856

  5. Direct Spectroscopic Observation of a Shallow Hydrogenlike Donor State in Insulating SrTiO3

    NASA Astrophysics Data System (ADS)

    Salman, Z.; Prokscha, T.; Amato, A.; Morenzoni, E.; Scheuermann, R.; Sedlak, K.; Suter, A.

    2014-10-01

    We present a direct spectroscopic observation of a shallow hydrogenlike muonium state in SrTiO3 which confirms the theoretical prediction that interstitial hydrogen may act as a shallow donor in this material. The formation of this muonium state is temperature dependent and appears below ˜70 K. From the temperature dependence we estimate an activation energy of ˜50 meV in the bulk and ˜23 meV near the free surface. The field and directional dependence of the muonium precession frequencies further supports the shallow impurity state with a rare example of a fully anisotropic hyperfine tensor. From these measurements we determine the strength of the hyperfine interaction and propose that the muon occupies an interstitial site near the face of the oxygen octahedron in SrTiO3. The observed shallow donor state provides new insight for tailoring the electronic and optical properties of SrTiO3-based oxide interface systems.

  6. Hydrogen chloride

    Integrated Risk Information System (IRIS)

    Hydrogen chloride ; CASRN 7647 - 01 - 0 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogeni

  7. Hydrogen sulfide

    Integrated Risk Information System (IRIS)

    Hydrogen sulfide ; 7783 - 06 - 4 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Effec

  8. Donor-Specific HLA Antibodies in Living Versus Deceased Donor Liver Transplant Recipients.

    PubMed

    Levitsky, J; Kaneku, H; Jie, C; Walsh, R C; Abecassis, M; Tambur, A R

    2016-08-01

    With less ischemia, improved donor selection and controlled procedures, living donor liver transplantation (LDLT) might lead to less HLA donor-specific antibody (DSA) formation or fewer adverse outcomes than deceased donor liver transplantation (DDLT). Using the multicenter A2ALL (Adult-to-Adult Living Donor Liver Transplantation Cohort Study) biorepository, we compared the incidence and outcomes of preformed and de novo DSAs between LDLT and DDLT. In total, 129 LDLT and 66 DDLT recipients were identified as having serial samples. The prevalence of preformed and de novo DSAs was not different between DDLT and LDLT recipients (p = 0.93). There was no association between patient survival and the timing (preformed vs. de novo), class (I vs. II) and relative levels of DSA between the groups; however, preformed DSA was associated with higher graft failure only in DDLT recipients (p = 0.01). De novo DSA was associated with graft failure regardless of liver transplant type (p = 0.005) but with rejection only in DDLT (p = 0.0001). On multivariate analysis, DSA was an independent risk factor for graft failure regardless of liver transplant type (p = 0.017, preformed; p = 0.002, de novo). In conclusion, although similar in prevalence, DSA may have more impact in DDLT than LDLT recipients. Although our findings need further validation, future research should more robustly test the effect of donor type and strategies to mitigate the impact of DSA. PMID:26896194

  9. Donor biopsy in living donor liver transplantation: is it still relevant in a developing country?

    PubMed

    Dorwal, P; Gautam, D; Sharma, D; Singh, D R; Raina, V

    2015-04-01

    Liver transplantation is an important modality of treatment for end-stage liver disease. Liver biopsy evaluation has been an important aspect of the donor evaluation protocol. With the advent of newer modalities of donor evaluation such as high resolution CT scan, fibroscan and NMR spectroscopy, the relevance of the liver biopsy appears to be diminishing. We investigated the usefulness of donor liver biopsy evaluation in patients who had been cleared by radiological investigations. We evaluated 184 donor liver biopsies performed over a one-year period and found that 18% showed >5% steatosis and around 40% showed portal inflammation, which was, however, minimal to mild. Fibrosis was detected in 10 cases (5.4%), 7 being in stage 1 and 3 in stage 2. Donors with these findings were not considered for transplantation. We conclude that the liver biopsy still continues to be relevant especially in a developing country and does add additional information to the diagnostic work-up of a liver donor. PMID:25890612

  10. Easy come, easy go. Retention of blood donors.

    PubMed

    van Dongen, A

    2015-08-01

    Retention of blood donors has benefits over recruitment of new blood donors. Retention is defined as preventing donors from lapsing and eventually becoming inactive. This review paper discusses literature on the importance of efforts to retain donors, specifically new donors, since lapsing is most common before the fifth donation. Studies have found that intention to donate, attitudes towards blood donation and self-efficacy (does one feel capable of donating blood) are predictors of blood donation. Feelings of 'warm glow' predict donation behaviour better than altruism. The existing literature further suggests that first time donors can be retained by paying extra attention to adverse events (vasovagal reactions and fatigue). These events could be reduced by drinking water and muscle tension exercises. Feelings of anxiety (in regular donors) and stress can further prevent donors from returning. Planning donations amongst busy lives can help retention, and suggestions are given on which interventions might be helpful. PMID:26399971

  11. Alternative donor transplant of benign primary hematologic disorders

    PubMed Central

    Tolar, J; Sodani, P; Symons, H

    2015-01-01

    Hematopoietic SCT is currently the only curative therapy for a range of benign inherited and acquired primary hematologic disorders in children, including BM failure syndromes and hemoglobinopathies. The preferred HLA-matched sibling donor is available for only about 25% of such children. However, there has been substantial progress over the last four decades in the use of alternative donors for those without a matched sibling—including HLA-matched unrelated donors, HLA-haploidentical related donors and unrelated-donor umbilical cord blood—so that it is now possible to find a donor for almost every child requiring an allograft. Below, we summarize the relative merits and limitations of the different alternative donors for benign hematologic conditions, first generally, and then in relation to specific disorders, and suggest recommendations for selecting such an alternative donor. PMID:25665040

  12. 21 CFR 660.31 - Suitability of the donor.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...) BIOLOGICS ADDITIONAL STANDARDS FOR DIAGNOSTIC SUBSTANCES FOR LABORATORY TESTS Reagent Red Blood Cells § 660.31 Suitability of the donor. Donors of peripheral blood for Reagent Red Blood Cells shall meet...

  13. 21 CFR 660.31 - Suitability of the donor.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...) BIOLOGICS ADDITIONAL STANDARDS FOR DIAGNOSTIC SUBSTANCES FOR LABORATORY TESTS Reagent Red Blood Cells § 660.31 Suitability of the donor. Donors of peripheral blood for Reagent Red Blood Cells shall meet...

  14. 21 CFR 640.12 - Suitability of donor.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... ADDITIONAL STANDARDS FOR HUMAN BLOOD AND BLOOD PRODUCTS Red Blood Cells § 640.12 Suitability of donor. The source blood for Red Blood Cells shall be obtained from a donor who meets the criteria for...

  15. 21 CFR 640.12 - Suitability of donor.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... ADDITIONAL STANDARDS FOR HUMAN BLOOD AND BLOOD PRODUCTS Red Blood Cells § 640.12 Suitability of donor. The source blood for Red Blood Cells shall be obtained from a donor who meets the criteria for...

  16. 21 CFR 640.12 - Suitability of donor.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... ADDITIONAL STANDARDS FOR HUMAN BLOOD AND BLOOD PRODUCTS Red Blood Cells § 640.12 Suitability of donor. The source blood for Red Blood Cells shall be obtained from a donor who meets the criteria for...

  17. 21 CFR 640.12 - Suitability of donor.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... ADDITIONAL STANDARDS FOR HUMAN BLOOD AND BLOOD PRODUCTS Red Blood Cells § 640.12 Suitability of donor. The source blood for Red Blood Cells shall be obtained from a donor who meets the criteria for...

  18. 21 CFR 660.31 - Suitability of the donor.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...) BIOLOGICS ADDITIONAL STANDARDS FOR DIAGNOSTIC SUBSTANCES FOR LABORATORY TESTS Reagent Red Blood Cells § 660.31 Suitability of the donor. Donors of peripheral blood for Reagent Red Blood Cells shall meet...

  19. 21 CFR 660.31 - Suitability of the donor.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...) BIOLOGICS ADDITIONAL STANDARDS FOR DIAGNOSTIC SUBSTANCES FOR LABORATORY TESTS Reagent Red Blood Cells § 660.31 Suitability of the donor. Donors of peripheral blood for Reagent Red Blood Cells shall meet...

  20. Detroit Commuter Hydrogen Project

    SciTech Connect

    Brooks, Jerry; Prebo, Brendan

    2010-07-31

    luggage. By collecting fuel use data for the two H2ICE buses, with both written driver logs and onboard telemetry devices, and for two conventional propane-gasoline powered buses in the same service, comparisons of operating efficiency and maintenance requirements were completed. Public opinion about the concept of hydrogen fuel was sampled with a rider survey throughout the demonstration. The demonstration was very effective in adding to the understanding of the application of hydrogen as a transportation fuel. The two 9 passenger H2ICE buses accumulated nearly 50,000 miles and carried 14,285 passengers. Data indicated the H2ICE bus fuel economy to be 9.4 miles/ gallon of gasoline equivalent (m/GGE) compared to the 10 passenger propane-gasoline bus average of 9.8 m/GGE over 32,400 miles. The 23- passenger bus averaged 7.4 m/GGE over 40,700 miles. Rider feedback from 1050 on-board survey cards was overwhelmingly positive with 99.6% indicating they would ride again on a hydrogen powered vehicle. Minimal maintenance was required for theses buses during the demonstration project, but a longer duration demonstration would be required to more adequately assess this aspect of the concept.

  1. Metallic Hydrogen

    NASA Astrophysics Data System (ADS)

    Silvera, Isaac; Zaghoo, Mohamed; Salamat, Ashkan

    2015-03-01

    Hydrogen is the simplest and most abundant element in the Universe. At high pressure it is predicted to transform to a metal with remarkable properties: room temperature superconductivity, a metastable metal at ambient conditions, and a revolutionary rocket propellant. Both theory and experiment have been challenged for almost 80 years to determine its condensed matter phase diagram, in particular the insulator-metal transition. Hydrogen is predicted to dissociate to a liquid atomic metal at multi-megabar pressures and T =0 K, or at megabar pressures and very high temperatures. Thus, its predicted phase diagram has a broad field of liquid metallic hydrogen at high pressure, with temperatures ranging from thousands of degrees to zero Kelvin. In a bench top experiment using static compression in a diamond anvil cell and pulsed laser heating, we have conducted measurements on dense hydrogen in the region of 1.1-1.7 Mbar and up to 2200 K. We observe a first-order phase transition in the liquid phase, as well as sharp changes in optical transmission and reflectivity when this phase is entered. The optical signature is that of a metal. The mapping of the phase line of this transition is in excellent agreement with recent theoretical predictions for the long-sought plasma phase transition to metallic hydrogen. Research supported by the NSF, Grant DMR-1308641, the DOE Stockpile Stewardship Academic Alliance Program, Grant DE-FG52-10NA29656, and NASA Earth and Space Science Fellowship Program, Award NNX14AP17H.

  2. Hydrolysis reactor for hydrogen production

    SciTech Connect

    Davis, Thomas A.; Matthews, Michael A.

    2012-12-04

    In accordance with certain embodiments of the present disclosure, a method for hydrolysis of a chemical hydride is provided. The method includes adding a chemical hydride to a reaction chamber and exposing the chemical hydride in the reaction chamber to a temperature of at least about 100.degree. C. in the presence of water and in the absence of an acid or a heterogeneous catalyst, wherein the chemical hydride undergoes hydrolysis to form hydrogen gas and a byproduct material.

  3. Ethical perspectives on living donor organ transplantation in Asia.

    PubMed

    Concejero, Allan M; Chen, Chao-Long

    2009-12-01

    Live donors are a continuing source of organ grafts for solid organ transplantation in Asia. Ethical issues surrounding the development of living donor organ transplantation in Eastern countries are different from those in Western countries. Donor safety is still the paramount concern in any donor operation. Issues on organ trafficking remain societal concerns in low-income nations. Religion, cultural background, economic prerogatives, and timely legislation contribute to the social acceptance and maturation of organ donation. PMID:19938130

  4. Imaging in Lung Transplantation: Surgical Considerations of Donor and Recipient.

    PubMed

    Backhus, Leah M; Mulligan, Michael S; Ha, Richard; Shriki, Jabi E; Mohammed, Tan-Lucien H

    2016-03-01

    Modifications in recipient and donor criteria and innovations in donor management hold promise for increasing rates of lung transplantation, yet availability of donors remains a limiting resource. Imaging is critical in the work-up of donor and recipient including identification of conditions that may portend to poor posttransplant outcomes or necessitate modifications in surgical technique. This article describes the radiologic principles that guide selection of patients and surgical procedures in lung transplantation. PMID:26896228

  5. Bending AdS waves with new massive gravity

    NASA Astrophysics Data System (ADS)

    Ayón-Beato, Eloy; Giribet, Gaston; Hassaïne, Mokhtar

    2009-05-01

    We study AdS-waves in the three-dimensional new theory of massive gravity recently proposed by Bergshoeff, Hohm, and Townsend. The general configuration of this type is derived and shown to exhibit different branches, with different asymptotic behaviors. In particular, for the special fine tuning m2 = ±1/(2l2), solutions with logarithmic fall-off arise, while in the range m2 > -1/(2l2), spacetimes with Schrödinger isometry group are admitted as solutions. Spacetimes that are asymptotically AdS3, both for the Brown-Henneaux and for the weakened boundary conditions, are also identified. The metric function that characterizes the profile of the AdS-wave behaves as a massive excitation on the spacetime, with an effective mass given by meff2 = m2-1/(2l2). For the critical value m2 = -1/(2l2), the value of the effective mass precisely saturates the Breitenlohner-Freedman bound for the AdS3 space where the wave is propagating on. The analogies with the AdS-wave solutions of topologically massive gravity are also discussed. Besides, we consider the coupling of both massive deformations to Einstein gravity and find the exact configurations for the complete theory, discussing all the different branches exhaustively. One of the effects of introducing the Chern-Simons gravitational term is that of breaking the degeneracy in the effective mass of the generic modes of pure New Massive Gravity, producing a fine structure due to parity violation. Another effect is that the zoo of exact logarithmic specimens becomes considerably enlarged.

  6. Coal liquefaction and hydrogenation: Processes and equipment. (Latest citations from the US Patent database). Published Search

    SciTech Connect

    Not Available

    1993-07-01

    The bibliography contains citations of selected patents concerning methods, processes, and apparatus for coal liquefaction and hydrogenation. Included are patents for catalytic two-stage, catalytic single-step, fixed-bed, hydrogen-donor, internal heat transfer, and multi-phase processes. Topics also include catalyst production, catalyst recovery, desulfurization, pretreatment of coals, energy recovery processes, solvent product separation, hydrogenating gases, and pollution control. (Contains 250 citations and includes a subject term index and title list.)

  7. ADS/CFT and QCD

    SciTech Connect

    Brodsky, Stanley J.; de Teramond, Guy F.; /Costa Rica U. /SLAC

    2007-02-21

    The AdS/CFT correspondence between string theory in AdS space and conformal .eld theories in physical spacetime leads to an analytic, semi-classical model for strongly-coupled QCD which has scale invariance and dimensional counting at short distances and color confinement at large distances. Although QCD is not conformally invariant, one can nevertheless use the mathematical representation of the conformal group in five-dimensional anti-de Sitter space to construct a first approximation to the theory. The AdS/CFT correspondence also provides insights into the inherently non-perturbative aspects of QCD, such as the orbital and radial spectra of hadrons and the form of hadronic wavefunctions. In particular, we show that there is an exact correspondence between the fifth-dimensional coordinate of AdS space z and a specific impact variable {zeta} which measures the separation of the quark and gluonic constituents within the hadron in ordinary space-time. This connection allows one to compute the analytic form of the frame-independent light-front wavefunctions, the fundamental entities which encode hadron properties and allow the computation of decay constants, form factors, and other exclusive scattering amplitudes. New relativistic lightfront equations in ordinary space-time are found which reproduce the results obtained using the 5-dimensional theory. The effective light-front equations possess remarkable algebraic structures and integrability properties. Since they are complete and orthonormal, the AdS/CFT model wavefunctions can also be used as a basis for the diagonalization of the full light-front QCD Hamiltonian, thus systematically improving the AdS/CFT approximation.

  8. Denitrification in Streams Impacted by Acid Mine Drainage: Effects of Iron, pH, and Potential Electron Donors

    NASA Astrophysics Data System (ADS)

    Baeseman, J. L.; Smith, R. L.; Silverstein, J.

    2003-12-01

    Acid mine drainage (AMD) contaminates between 8,000 and 16,000 km of streams on U.S. Forest Service land in the Western United States and more than 7,000 km of stream in the Eastern U.S. Relatively little is known about nitrogen cycling in these acidic, heavy metal laden streams, however, denitrification can be inhibited under low pH conditions. The objective of this research was to examine AMD sediments for bacteria capable of denitrification. The process of denitrification is known to increase pH, which may be particularly important in acidic environments. Denitrification potential was assessed in AMD sediments from several Colorado AMD impacted streams ranging from pH 2.6 to 4.91, using microcosm incubations with fresh sediments. Added nitrate was immediately reduced to nitrogen gas without any lag period, indicating that denitrification was actively occurring in these environments. Rates varied from 0.33 to 2.52 umoles NO3-N/ g-sediment/ day depending on the site. The pH of the microcosms increased between 0.23 to 1.49 pH units in 5 days, depending on the site. Additional microcosm studies were conducted to examine the effects of iron concentrations (Fe2+ and Fe3+), initial pH conditions, and several potential electron donors. Addition of iron above ambient concentrations seemed to have little effect on denitrification rates, whereas rates increased with increasing initial pH. The addition of carbon and hydrogen stimulated denitrification rates, which in turn increased the rise in pH. These results suggest that not only is denitrification possible in AMD streams, it may also be a useful remediation option, if suitable methods can be found to stimulate activity.

  9. Polymer formulations for gettering hydrogen

    DOEpatents

    Shepodd, Timothy J.; Even, Jr., William R.

    2000-01-01

    A novel method for preparing a hydrogenation composition comprising organic polymer molecules having carbon--carbon double bonds, for removing hydrogen from the atmosphere within enclosed spaces and particularly from atmospheres within enclosed spaces that contain air, water vapor, oxygen, carbon dioxide or ammonia. The organic polymers molecules containing carbon--carbon double bonds throughout their structures, preferably polybutadiene, polyisoprene and derivatives thereof, intimately mixed with an insoluble noble metal catalyst composition. High molecular weight polymers may be added to the organic polymer/catalyst mixture in order to improve their high temperature performance. The hydrogenation composition is prepared by dispersing the polymers in a suitable solvent, forming thereby a solution suspension, flash-freezing droplets of the solution in a liquid cryogen, freeze-drying the frozen droplets to remove frozen solvent incorporated in the droplets, and recovering the dried powder thus formed.

  10. 21 CFR 640.63 - Suitability of donor.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... ADDITIONAL STANDARDS FOR HUMAN BLOOD AND BLOOD PRODUCTS Source Plasma § 640.63 Suitability of donor. (a) Method of determining. The suitability of a donor for Source Plasma shall be determined by a qualified... year. (2)(i) A donor who is to be immunized for the production of high-titer plasma shall be...

  11. 21 CFR 640.63 - Suitability of donor.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... ADDITIONAL STANDARDS FOR HUMAN BLOOD AND BLOOD PRODUCTS Source Plasma § 640.63 Suitability of donor. (a) Method of determining. The suitability of a donor for Source Plasma shall be determined by a qualified... year. (2)(i) A donor who is to be immunized for the production of high-titer plasma shall be...

  12. 21 CFR 640.63 - Suitability of donor.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... ADDITIONAL STANDARDS FOR HUMAN BLOOD AND BLOOD PRODUCTS Source Plasma § 640.63 Suitability of donor. (a) Method of determining. The suitability of a donor for Source Plasma shall be determined by a qualified... year. (2)(i) A donor who is to be immunized for the production of high-titer plasma shall be...

  13. 21 CFR 640.63 - Suitability of donor.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... ADDITIONAL STANDARDS FOR HUMAN BLOOD AND BLOOD PRODUCTS Source Plasma § 640.63 Suitability of donor. (a) Method of determining. The suitability of a donor for Source Plasma shall be determined by a qualified... year. (2)(i) A donor who is to be immunized for the production of high-titer plasma shall be...

  14. 21 CFR 640.63 - Suitability of donor.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... ADDITIONAL STANDARDS FOR HUMAN BLOOD AND BLOOD PRODUCTS Source Plasma § 640.63 Suitability of donor. (a) Method of determining. The suitability of a donor for Source Plasma shall be determined by a qualified... year. (2)(i) A donor who is to be immunized for the production of high-titer plasma shall be...

  15. Ultraviolet asymptotics and singular dynamics of AdS perturbations

    NASA Astrophysics Data System (ADS)

    Craps, Ben; Evnin, Oleg; Vanhoof, Joris

    2015-10-01

    Important insights into the dynamics of spherically symmetric AdS-scalar field perturbations can be obtained by considering a simplified time-averaged theory accurately describing perturbations of amplitude ɛ on time-scales of order 1/ ɛ 2. The coefficients of the time-averaged equations are complicated expressions in terms of the AdS scalar field mode functions, which are in turn related to the Jacobi polynomials. We analyze the behavior of these coefficients for high frequency modes. The resulting asymptotics can be useful for understanding the properties of the finite-time singularity in solutions of the time-averaged theory recently reported in the literature. We highlight, in particular, the gauge dependence of this asymptotics, with respect to the two most commonly used gauges. The harsher growth of the coefficients at large frequencies in higher-dimensional AdS suggests strengthening of turbulent instabilities in higher dimensions. In the course of our derivations, we arrive at recursive relations for the coefficients of the time-averaged theory that are likely to be useful for evaluating them more efficiently in numerical simulations.

  16. Hydrogen environment embrittlement.

    NASA Technical Reports Server (NTRS)

    Gray, H. R.

    1972-01-01

    Hydrogen embrittlement is classified into three types: internal reversible hydrogen embrittlement, hydrogen reaction embrittlement, and hydrogen environment embrittlement. Characteristics of and materials embrittled by these types of hydrogen embrittlement are discussed. Hydrogen environment embrittlement is reviewed in detail. Factors involved in standardizing test methods for detecting the occurrence of and evaluating the severity of hydrogen environment embrittlement are considered. The effects of test technique, hydrogen pressure, purity, strain rate, stress concentration factor, and test temperature are discussed.

  17. Transuranic drum hydrogen explosion tests

    SciTech Connect

    Dykes, K.L.; Meyer, M.L.

    1991-06-01

    Radiolysis of transuranic (TRU) waste can produce flammable ({gt}4%) mixtures of hydrogen gas in 55 gallon vented waste storage drums. Explosion testing was conducted at the E. I. duPont Explosion Hazards Laboratory to determine the minimum concentration at which a drum lid removal occurs. A secondary objective was to investigate the maximum pressure and rate of pressure rise as a function of hydrogen concentration. Prior to beginning any drum explosion tests, small-scale pressure vessel tests and drum mixing tests were completed. The pressure vessel tests established a relationship between hydrogen concentration and the maximum pressure and pressure rise. These small-scale tests were used to establish the concentration range over which a drum lid removal might occur. Mixing tests were also conducted to determine the equilibration times for two different hydrogen-air mixtures in a TRU drum. Nine successful drum explosion tests were conducted over a hydrogen concentration range of 13--36% (v/v), test results suggest total integrity failure via drum lid removal will not occur below 15% (v/v). Controlled small-scale pressure vessel tests were conducted over a range of 5--50% (v/v) to determine the pressure and pressure rise as a function of hydrogen concentration. No similar relationship could be established for the drum explosion tests due to the variability in drum lid sealing and retaining ring closure. Mixing tests conducted at 5% and 25% (v/v) indicate adding pure hydrogen to the middle of a drum causes some initial stratification along the drum length, but the air and hydrogen become well-mixed after 50 minutes. 4 refs., 11 figs., 2 tabs.

  18. Noble Metals Would Prevent Hydrogen Embrittlement

    NASA Technical Reports Server (NTRS)

    Paton, N. E.; Frandsen, J. D.

    1987-01-01

    According to proposal, addition of small amounts of noble metals makes iron- and nickel-based alloys less susceptible to embrittlement by hydrogen. Metallurgists demonstrated adding 0.6 to 1.0 percent by weight of Pd or Pt eliminates stress/corrosion cracking in type 4130 steel. Proposal based on assumption that similar levels (0.5 to 1.0 weight percent) of same elements effective against hydrogen embrittlement.

  19. Antidiffusive velocities for multipass donor cell advection

    SciTech Connect

    Margolin, L.; Smolarkiewicz, P.K.

    1999-01-01

    Multidimensional positive definite advection transport algorithm (MPDATA) is an iterative process for approximating the advection equation, which uses a donor cell approximation to compensate for the truncation error of the originally specified donor cell scheme. This step may be repeated an arbitrary number of times, leading to successfully more accurate solutions to the advection equation. In this paper, the authors show how to sum the successive approximations analytically to find a single antidiffusive velocity that represents the effects of an arbitrary number of passes. The analysis is first done in one dimension to illustrate the method and then is repeated in two dimensions. The existence of cross terms in the truncation analysis of the two-dimensional equations introduces an extra complication into the calculation. The authors discuss the implementation of the antidiffusive velocities and provide some examples of applications, including a third-order accurate scheme.

  20. Antidiffusive velocities for multipass donor cell advection

    SciTech Connect

    Margolin, L.G. ); Smolarkiewicz, P.K. )

    1989-12-01

    Smolarkiewicz describes an iterative process for approximating the advection equation. Basically, he uses a donor cell approximation to correct for the truncation error of the originally specified donor cell scheme. This step may be repeated an arbitrary number of times leading to successively more accurate solutions to the advection equation. In this report, we show how to sum the successive approximations analytically to find a single antidiffusive velocity that represents the effects of an arbitrary number of passes. The analysis is first done dimension to illustrate the method. The analysis is then repeated in two dimensions. The existence of cross terms in the truncation analysis of the two-dimensional equations introduces an extra complication into the calculation. We discuss the implementation of our new antidiffusive velocities and provide some examples of applications. 6 refs., 5 figs., 4 tabs.

  1. Living donor liver transplantation in Europe

    PubMed Central

    Capobianco, Ivan; Panaro, Fabrizio; Di Francesco, Fabrizio; Troisi, Roberto; Sainz-Barriga, Mauricio; Muiesan, Paolo; Königsrainer, Alfred; Testa, Giuliano

    2016-01-01

    Living donor liver transplantation (LDLT) sparked significant interest in Europe when the first reports of its success from USA and Asia were made public. Many transplant programs initiated LDLT and some of them especially in Germany and Belgium became a point of reference for many patients and important contributors to the advancement of the field. After the initial enthusiasm, most of the European programs stopped performing LDLT and today the overall European activity is concentrated in a few centers and the number of living donor liver transplants is only a single digit fraction of the overall number of liver transplants performed. In this paper we analyse the present European activities and highlight the European contribution to the advancement of the field of LDLT. PMID:27115011

  2. Psychiatric Aspects of Artificial Insemination (Donor)

    PubMed Central

    Watters, W. W.; Sousa-Poza, J.

    1966-01-01

    Artificial insemination (donor) [A.I.D.] in humans is a medical procedure that has been carried out for roughly 50 years. Its legal status has not yet been established; its moral implications are still hotly contested, and its psychological and psychiatric implications are only now coming under scientific scrutiny. The use of this procedure in couples who are psychologically unsuited for it can have unfortunate consequences. The obstetrician should seek the assistance of a dynamically oriented psychiatrist in screening couples who ask for artificial insemination (donor). Parenthood, in line with psychoanalytic ego psychology, is seen as a phase of ego development. The potential for mothering and fathering children is a later stage in growth than the capacity to conceive and sire them. It is the psychiatrist's role to assess the couple's motivation for A.I.D. in the light of the extent to which they have achieved this degree of ego development. PMID:20328602

  3. Living-donor kidney transplantation: a review of the current practices for the live donor.

    PubMed

    Davis, Connie L; Delmonico, Francis L

    2005-07-01

    The first successful living-donor kidney transplant was performed 50 yr ago. Since then, in a relatively brief period of medical history, living kidney transplantation has become the preferred treatment for those with ESRD. Organ replacement from either a live or a deceased donor is preferable to dialysis therapy because transplantation provides a better quality of life and improved survival. The advantages of live versus deceased donor transplantation now are readily apparent as it affords earlier transplantation and the best long-term survival. Live kidney donation has also been fostered by the technical advance of laparoscopic nephrectomy and immunologic maneuvers that can overcome biologic obstacles such as HLA disparity and ABO or cross-match incompatibility. Congressional legislation has provided an important model to remove financial disincentives to being a live donor. Federal employees now are afforded paid leave and coverage for travel expenses. Candidates for renal transplantation are aware of these developments, and they have become less hesitant to ask family members, spouses, or friends to become live kidney donors. Living donation as practiced for the past 50 yr has been safe with minimal immediate and long-term risk for the donor. However, the future experience may not be the same as our society is becoming increasingly obese and developing associated health problems. In this environment, predicting medical futures is less precise than in the past. Even so, isolated abnormalities such as obesity and in some instances hypertension are no longer considered absolute contraindications to donation. These and other medical risks bring additional responsibility in such circumstances to track the unknown consequences of a live-donor nephrectomy. PMID:15930096

  4. Taking a Step Forward in Laparoscopic Donor Nephrectomy: Transvaginal Retrieval of Donor's Kidney.

    PubMed

    Tan, Ying Hao; Lim, Yu Ming Joel; Ng, Ying Woo; Tiong, Ho Yee

    2016-09-01

    Laparoscopic donor nephrectomy has been broadly recognized as the gold standard for kidney procurement used in kidney transplantation where it is not uncommon for donors to experience discomfort and aesthetic dissatisfaction over larger incision site. Natural orifice transluminal endoscopic surgery is a surgical approach that allows scarless intraabdominal operations through natural orifices, such as the vagina. In this case report, we describe the first case of transvaginal retrieval of donor's kidney at the National University Hospital, Singapore. A 51-year-old Malay lady with no significant medical history volunteered to a living-related kidney donor. Perioperative antibiotics were administered. A 12 mm Excel port was placed over the left iliac fossa with camera insertion. Two additional ports were inserted over the left rectus sheath edge and left costal margin under direct vision. An additional 5 mm port at the left loin was placed for lateral retraction. A vaginal probe was then inserted to facilitate posterior colpotomy and transection of the left uterosacral ligament. Pneumoperitoneum was subsequently maintained with a LiNA McCartney(®) Tube. A 15 mm Endocatch(®) bag was inserted for retrieval of the kidney. The left kidney was placed in the Endocatch bag after transection of the hilar vessels where the kidney was retrieved vaginally with ease. Colpotomy was closed vaginally using Vicryl-0 continuous suture. Total blood loss was noted as 50 mL with warm ischemia time being 7 minutes and the entire retrieval taking totally 20 minutes. Postoperative recovery was uneventful and the donor was discharged stable 3 days postoperation. The transplanted kidney retained normal graft function. Colpotomy retrieval for donor nephrectomy presents an innovative method for specimen retrieval with minimal disruption of donor anatomy. Doing away with laparotomy for kidney retrieval has indeed shown a reduction in recovery time, reduced postoperative pain, and

  5. [The protocol for multi organ donor management].

    PubMed

    Kucewicz, Ewa; Wojarski, Jacek; Zegleń, Sławomir; Saucha, Wojciech; Maciejewski, Tomasz; Pacholewicz, Jerzy; Przybylski, Roman; Knapik, Piotr; Zembala, Marian

    2009-01-01

    Identification and preparation of a potential organ donor requires careful and meticulous intensive care, so that the organs may be harvested in the best possible condition for transplantation. The protocol consists of three key elements: (1) monitoring and haemodynamicstabilisation, (2) hormonal therapy, and (3) adequate mechanical ventilation and nosocomial pneumonia prophylaxis. Standard haemodynamic monitoring should consist of a 12 lead EGG, and direct monitoring of arterial and central venous pressures. Pulmonary artery catheterisation is indicated in donors with a left ventricular ejection fraction (LVEF) below 45%. PCWP should be kept at around 12 mm Hg, Cl at greater than 2.4 L m(-2), and SVR between 800 and 1200 dyn s(-1) cm(-5). When a vasopressor is necessary, vasopressin should be used as the drug of choice. If vasopressin is not available, noradrenaline or adrenaline may be used. Haemoglobin concentration should be maintained between 5.5-6.2 mmol L(-1). In a potential heart donor, troponin concentration should be checked daily. Neutral thermal conditions should be maintained using a warm air blower. A brain dead patient cannot maintain adequate pituitary function, therefore hormone replacement therapy with methylprednisolone, thyroxin and desmopressin is indicated. Glucose concentrations should be kept within the normal range, using insulin if necessary. The lung harvesting protocol should be similarto ARDS treatment guidelines (optimal PEEP, low tidal volumes). Lung recruitment manoeuvres, and aggressive prevention and treatment of nosocomial infection are essential. PMID:20201348

  6. Successful Treatment of Chronic Donor Site Pain

    PubMed Central

    Yanow, Jennifer H; Lorenzo, Luigi Di; Worosilo, Sharon C; Pappagallo, Marco

    2015-01-01

    Introduction: This is a case presentation of a 45-year-old male with chronic donor site pain following autologous iliac crest bone harvest successfully treated with superior cluneal nerve blockade. Donor site pain following autologous bone harvest is a common postoperative complication of lumbar fusion procedures that can cause significant morbidity and diminish quality of life, even in the context of an otherwise successful surgery. Dysfunction of the superior cluneal nerves is an etiology of this chronic pain. The patient’s medical history, attempted treatments, and literature were reviewed. Case Presentation: A 45-year-old male with a six year history of severe pain over the right iliac crest following an otherwise successful lumbar laminectomy and fusion underwent two sets of superior cluneal nerve blocks, with sustained relief of more than 80% at seven months follow up. Conclusions: Donor site pain following autologous iliac crest bone harvest is a common surgical complication that is often resistant to conservative treatments such as physical therapy and oral medications. Blockade of the superior cluneal nerves is a safe and technically simple procedure that may result in long-term pain relief, obviating the need to consider more invasive options. PMID:26587399

  7. New Features in ADS Labs

    NASA Astrophysics Data System (ADS)

    Accomazzi, Alberto; Kurtz, M. J.; Henneken, E. A.; Grant, C. S.; Thompson, D.; Di Milia, G.; Luker, J.; Murray, S. S.

    2013-01-01

    The NASA Astrophysics Data System (ADS) has been working hard on updating its services and interfaces to better support our community's research needs. ADS Labs is a new interface built on the old tried-and-true ADS Abstract Databases, so all of ADS's content is available through it. In this presentation we highlight the new features that have been developed in ADS Labs over the last year: new recommendations, metrics, a citation tool and enhanced fulltext search. ADS Labs has long been providing article-level recommendations based on keyword similarity, co-readership and co-citation analysis of its corpus. We have now introduced personal recommendations, which provide a list of articles to be considered based on a individual user's readership history. A new metrics interface provides a summary of the basic impact indicators for a list of records. These include the total and normalized number of papers, citations, reads, and downloads. Also included are some of the popular indices such as the h, g and i10 index. The citation helper tool allows one to submit a set of records and obtain a list of top 10 papers which cite and/or are cited by papers in the original list (but which are not in it). The process closely resembles the network approach of establishing "friends of friends" via an analysis of the citation network. The full-text search service now covers more than 2.5 million documents, including all the major astronomy journals, as well as physics journals published by Springer, Elsevier, the American Physical Society, the American Geophysical Union, and all of the arXiv eprints. The full-text search interface interface allows users and librarians to dig deep and find words or phrases in the body of the indexed articles. ADS Labs is available at http://adslabs.org

  8. The AdS central charge in string theory

    NASA Astrophysics Data System (ADS)

    Troost, Jan

    2011-11-01

    We evaluate the vacuum expectation value of the central charge operator in string theory in an AdS3 vacuum. Our calculation provides a rare non-zero one-point function on a spherical worldsheet. The evaluation involves the regularization both of a worldsheet ultraviolet divergence (associated to the infinite volume of the conformal Killing group), and a space-time infrared divergence (corresponding to the infinite volume of space-time). The two divergences conspire to give a finite result, which is the classical general relativity value for the central charge, corrected in bosonic string theory by an infinite series of tree level higher derivative terms.

  9. Small black holes in global AdS spacetime

    NASA Astrophysics Data System (ADS)

    Jokela, Niko; Pönni, Arttu; Vuorinen, Aleksi

    2016-04-01

    We study the properties of two-point functions and quasinormal modes in a strongly coupled field theory holographically dual to a small black hole in global anti-de Sitter spacetime. Our results are seen to smoothly interpolate between known limits corresponding to large black holes and thermal AdS space, demonstrating that the Son-Starinets prescription works even when there is no black hole in the spacetime. Omitting issues related to the internal space, the results can be given a field theory interpretation in terms of the microcanonical ensemble, which provides access to energy densities forbidden in the canonical description.

  10. Entanglement entropy and duality in AdS4

    NASA Astrophysics Data System (ADS)

    Bakas, Ioannis; Pastras, Georgios

    2015-07-01

    Small variations of the entanglement entropy δS and the expectation value of the modular Hamiltonian δE are computed holographically for circular entangling curves in the boundary of AdS4, using gravitational perturbations with general boundary conditions in spherical coordinates. Agreement with the first law of thermodynamics, δS = δE, requires that the line element of the entangling curve remains constant. In this context, we also find a manifestation of electric-magnetic duality for the entanglement entropy and the corresponding modular Hamiltonian, following from the holographic energy-momentum/Cotton tensor duality.

  11. Fake gaps in AdS3/CFT2

    NASA Astrophysics Data System (ADS)

    Belin, Alexandre; Castro, Alejandra; Hung, Ling-Yan

    2015-11-01

    We discuss properties of interpolating geometries in three dimensional gravity in the presence of a chiral anomaly. This anomaly, which introduces an unbalance between left and right central charges, is protected under RG flows. For this simple reason it is impossible to gap a system with such an anomaly. Our goal is to discuss how holography captures this basic and robust feature. We demonstrate the absence of a mass gap by analysing the linearized spectrum and holographic entanglement entropy of these backgrounds in the context of AdS3/CFT2.

  12. Pure Spinors in AdS and Lie Algebra Cohomology

    NASA Astrophysics Data System (ADS)

    Mikhailov, Andrei

    2014-10-01

    We show that the BRST cohomology of the massless sector of the Type IIB superstring on AdS5 × S 5 can be described as the relative cohomology of an infinite-dimensional Lie superalgebra. We explain how the vertex operators of ghost number 1, which correspond to conserved currents, are described in this language. We also give some algebraic description of the ghost number 2 vertices, which appears to be new. We use this algebraic description to clarify the structure of the zero mode sector of the ghost number two states in flat space, and initiate the study of the vertices of the higher ghost number.

  13. Internal structure of charged AdS black holes

    NASA Astrophysics Data System (ADS)

    Bhattacharjee, Srijit; Sarkar, Sudipta; Virmani, Amitabh

    2016-06-01

    When an electrically charged black hole is perturbed, its inner horizon becomes a singularity, often referred to as the Poisson-Israel mass inflation singularity. Ori constructed a model of this phenomenon for asymptotically flat black holes, in which the metric can be determined explicitly in the mass inflation region. In this paper we implement the Ori model for charged AdS black holes. We find that the mass function inflates faster than the flat space case as the inner horizon is approached. Nevertheless, the mass inflation singularity is still a weak singularity: Although spacetime curvature becomes infinite, tidal distortions remain finite on physical objects attempting to cross it.

  14. Hydrogen scavengers

    SciTech Connect

    Carroll, David W.; Salazar, Kenneth V.; Trkula, Mitchell; Sandoval, Cynthia W.

    2002-01-01

    There has been invented a codeposition process for fabricating hydrogen scavengers. First, a .pi.-bonded allylic organometallic complex is prepared by reacting an allylic transition metal halide with an organic ligand complexed with an alkali metal; and then, in a second step, a vapor of the .pi.-bonded allylic organometallic complex is combined with the vapor of an acetylenic compound, irradiated with UV light, and codeposited on a substrate.

  15. High Resolution Structures of the Human ABO(H) Blood Group Enzymes in Complex with Donor Analogs Reveal That the Enzymes Utilize Multiple Donor Conformations to Bind Substrates in a Stepwise Manner.

    PubMed

    Gagnon, Susannah M L; Meloncelli, Peter J; Zheng, Ruixiang B; Haji-Ghassemi, Omid; Johal, Asha R; Borisova, Svetlana N; Lowary, Todd L; Evans, Stephen V

    2015-11-01

    Homologous glycosyltransferases α-(1→3)-N-acetylgalactosaminyltransferase (GTA) and α-(1→3)-galactosyltransferase (GTB) catalyze the final step in ABO(H) blood group A and B antigen synthesis through sugar transfer from activated donor to the H antigen acceptor. These enzymes have a GT-A fold type with characteristic mobile polypeptide loops that cover the active site upon substrate binding and, despite intense investigation, many aspects of substrate specificity and catalysis remain unclear. The structures of GTA, GTB, and their chimeras have been determined to between 1.55 and 1.39 Å resolution in complex with natural donors UDP-Gal, UDP-Glc and, in an attempt to overcome one of the common problems associated with three-dimensional studies, the non-hydrolyzable donor analog UDP-phosphono-galactose (UDP-C-Gal). Whereas the uracil moieties of the donors are observed to maintain a constant location, the sugar moieties lie in four distinct conformations, varying from extended to the "tucked under" conformation associated with catalysis, each stabilized by different hydrogen bonding partners with the enzyme. Further, several structures show clear evidence that the donor sugar is disordered over two of the observed conformations and so provide evidence for stepwise insertion into the active site. Although the natural donors can both assume the tucked under conformation in complex with enzyme, UDP-C-Gal cannot. Whereas UDP-C-Gal was designed to be "isosteric" with natural donor, the small differences in structure imposed by changing the epimeric oxygen atom to carbon appear to render the enzyme incapable of binding the analog in the active conformation and so preclude its use as a substrate mimic in GTA and GTB. PMID:26374898

  16. Double-donor complex in vertically coupled quantum dots in a threading magnetic field.

    PubMed

    Manjarres-García, Ramón; Escorcia-Salas, Gene Elizabeth; Manjarres-Torres, Javier; Mikhailov, Ilia D; Sierra-Ortega, José

    2012-01-01

    We consider a model of hydrogen-like artificial molecule formed by two vertically coupled quantum dots in the shape of axially symmetrical thin layers with on-axis single donor impurity in each of them and with the magnetic field directed along the symmetry axis. We present numerical results for energies of some low-lying levels as functions of the magnetic field applied along the symmetry axis for different quantum dot heights, radii, and separations between them. The evolution of the Aharonov-Bohm oscillations of the energy levels with the increase of the separation between dots is analyzed. PMID:23013550

  17. Seeded on-surface supramolecular growth for large area conductive donor-acceptor assembly.

    PubMed

    Goudappagouda; Chithiravel, Sundaresan; Krishnamoorthy, Kothandam; Gosavi, Suresh W; Babu, Sukumaran Santhosh

    2015-07-01

    Charge transport features of organic semiconductor assemblies are of paramount importance. However, large-area extended supramolecular structures of donor-acceptor combinations with controlled self-assembly pathways are hardly accessible. In this context, as a representative example, seeded on-surface supramolecular growth of tetrathiafulvalene and tetracyano-p-quinodimethane (TTF-TCNQ) using active termini of solution-formed sheaves has been introduced to form an extended assembly. We demonstrate for the first time, the creation of a large-area donor-acceptor assembly on the surface, which is practically very tedious, using a seeded, evaporation-assisted growth process. The excellent molecular ordering in this assembly is substantiated by its good electrical conductivity (~10⁻² S cm⁻¹). The on-surface assembly via both internally formed and externally added sheaf-like seeds open new pathways in supramolecular chemistry and device applications. PMID:26036616

  18. Transport through a single donor in p-type silicon

    NASA Astrophysics Data System (ADS)

    Miwa, J. A.; Mol, J. A.; Salfi, J.; Rogge, S.; Simmons, M. Y.

    2013-07-01

    Single phosphorus donors in silicon are promising candidates as qubits in the solid state. Here, we present low temperature scanning probe microscopy and spectroscopy measurements of individual phosphorus dopants deliberately placed in p-type silicon ˜1 nm below the surface. The ability to image individual dopants combined with scanning tunnelling spectroscopy allows us to directly study the transport mechanism through the donor. We show that for a single P donor, transport is dominated by a minority carrier recombination process with the surrounding p-type matrix. The understanding gained will underpin future studies of atomically precise mapping of donor-donor interactions in silicon.

  19. Introducing ADS 2.0

    NASA Astrophysics Data System (ADS)

    Accomazzi, Alberto; Kurtz, M. J.; Henneken, E. A.; Grant, C. S.; Thompson, D.; Luker, J.; Chyla, R.; Murray, S. S.

    2014-01-01

    In the spring of 1993, the Smithsonian/NASA Astrophysics Data System (ADS) first launched its bibliographic search system. It was known then as the ADS Abstract Service, a component of the larger Astrophysics Data System effort which had developed an interoperable data system now seen as a precursor of the Virtual Observatory. As a result of the massive technological and sociological changes in the field of scholarly communication, the ADS is now completing the most ambitious technological upgrade in its twenty-year history. Code-named ADS 2.0, the new system features: an IT platform built on web and digital library standards; a new, extensible, industrial strength search engine; a public API with various access control capabilities; a set of applications supporting search, export, visualization, analysis; a collaborative, open source development model; and enhanced indexing of content which includes the full-text of astronomy and physics publications. The changes in the ADS platform affect all aspects of the system and its operations, including: the process through which data and metadata are harvested, curated and indexed; the interface and paradigm used for searching the database; and the follow-up analysis capabilities available to the users. This poster describes the choices behind the technical overhaul of the system, the technology stack used, and the opportunities which the upgrade is providing us with, namely gains in productivity and enhancements in our system capabilities.

  20. Pediatric donor cell leukemia after allogeneic hematopoietic stem cell transplantation in AML patient from related donor.

    PubMed

    Bobadilla-Morales, Lucina; Pimentel-Gutiérrez, Helia J; Gallegos-Castorena, Sergio; Paniagua-Padilla, Jenny A; Ortega-de-la-Torre, Citlalli; Sánchez-Zubieta, Fernando; Silva-Cruz, Rocio; Corona-Rivera, Jorge R; Zepeda-Moreno, Abraham; González-Ramella, Oscar; Corona-Rivera, Alfredo

    2015-01-01

    Here we present a male patient with acute myeloid leukemia (AML) initially diagnosed as M5 and with karyotype 46,XY. After induction therapy, he underwent a HLA-matched allogeneic hematopoietic stem cell transplantation, and six years later he relapsed as AML M1 with an abnormal karyotype //47,XX,+10[2]/47,XX,+11[3]/48,XX,+10,+11[2]/46,XX[13]. Based on this, we tested the possibility of donor cell origin by FISH and molecular STR analysis. We found no evidence of Y chromosome presence by FISH and STR analysis consistent with the success of the allogeneic hematopoietic stem cell transplantation from the female donor. FISH studies confirmed trisomies and no evidence of MLL translocation either p53 or ATM deletion. Additionally 28 fusion common leukemia transcripts were evaluated by multiplex reverse transcriptase-polymerase chain reaction assay and were not rearranged. STR analysis showed a complete donor chimerism. Thus, donor cell leukemia (DCL) was concluded, being essential the use of cytological and molecular approaches. Pediatric DCL is uncommon, our patient seems to be the sixth case and additionally it presented a late donor cell leukemia appearance. Different extrinsic and intrinsic mechanisms have been considered to explain this uncommon finding as well as the implications to the patient. PMID:25674158

  1. 76 FR 65735 - Draft Guidance for Industry: Implementation of Acceptable Abbreviated Donor History Questionnaire...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-24

    ... Abbreviated Donor History Questionnaire and Accompanying Materials for Use in Screening Frequent Donors of... entitled ``Guidance for Industry: Implementation of Acceptable Abbreviated Donor History Questionnaire and.... The draft guidance document recognizes the abbreviated donor history questionnaire and...

  2. 21 CFR 1271.50 - How do I determine whether a donor is eligible?

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... HUMAN CELLS, TISSUES, AND CELLULAR AND TISSUE-BASED PRODUCTS Donor Eligibility § 1271.50 How do I... document the eligibility of a cell or tissue donor. (b) Eligible donor. A donor is eligible under...

  3. 21 CFR 1271.50 - How do I determine whether a donor is eligible?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... HUMAN CELLS, TISSUES, AND CELLULAR AND TISSUE-BASED PRODUCTS Donor Eligibility § 1271.50 How do I... document the eligibility of a cell or tissue donor. (b) Eligible donor. A donor is eligible under...

  4. Gettering of donor impurities by V in GaAs and the growth of semi-insulating crystals

    NASA Technical Reports Server (NTRS)

    Ko, K. Y.; Lagowski, J.; Gatos, H. C.

    1989-01-01

    Vanadium added to the GaAs melt getters shallow donor impurities (Si and S) and decreases their concentration in the grown crystals. This gettering is driven by chemical reactions in the melt rather than in the solid. Employing V gettering, reproducibly semi-insulating GaAs were grown by horizontal Bridgman and liquid-encapsulated Czochralski techniques, although V did not introduce any midgap energy levels. The compensation mechanism in these crystals was controlled by the balance between the native midgap donor EL2 and residual shallow acceptors. Vanadium gettering contributed to the reduction of the concentration of shallow donors below the concentration of acceptors. The present findings clarify the long-standing controversy on the role of V in achieving semi-insulating GaAs.

  5. Computer applications in the search for unrelated stem cell donors.

    PubMed

    Müller, Carlheinz R

    2002-08-01

    The majority of patients which are eligible for a blood stem cell transplantation from an allogeneic donor do not have a suitable related donor so that an efficient unrelated donor search is a prerequisite for this treatment. Currently, there are over 7 million volunteer donors in the files of 50 registries in the world and in most countries the majority of transplants are performed from a foreign donor. Evidently, computer and communication technology must play a crucial role in the complex donor search process on the national and international level. This article describes the structural elements of the donor search process and discusses major systematic and technical issues to be addressed in the development and evolution of the supporting telematic systems. The theoretical considerations are complemented by a concise overview over the current state of the art which is given by describing the scope, relevance, interconnection and technical background of three major national and international computer appliances: The German Marrow Donor Information System (GERMIS) and the European Marrow Donor Information System (EMDIS) are interoperable business-to-business e-commerce systems and Bone Marrow Donors World Wide (BMDW) is the basic international donor information desk on the web. PMID:12216954

  6. Critical gravity on AdS2 spacetimes

    NASA Astrophysics Data System (ADS)

    Myung, Yun Soo; Kim, Yong-Wan; Park, Young-Jai

    2011-09-01

    We study the critical gravity in two-dimensional anti-de Sitter (AdS2) spacetimes, which was obtained from the cosmological topologically massive gravity (TMGΛ) in three dimensions by using the Kaluza-Klein dimensional reduction. We perform the perturbation analysis around AdS2, which may correspond to the near-horizon geometry of the extremal Banados, Teitelboim, and Zanelli (BTZ) black hole obtained from the TMGΛ with identification upon uplifting three dimensions. A massive propagating scalar mode δF satisfies the second-order differential equation away from the critical point of K=l, whose solution is given by the Bessel functions. On the other hand, δF satisfies the fourth-order equation at the critical point. We exactly solve the fourth-order equation, and compare it with the log gravity in two dimensions. Consequently, the critical gravity in two dimensions could not be described by a massless scalar δFml and its logarithmic partner δFlog⁡4th.

  7. Conserved charges in timelike warped AdS3 spaces

    NASA Astrophysics Data System (ADS)

    Donnay, L.; Fernández-Melgarejo, J. J.; Giribet, G.; Goya, A.; Lavia, E.

    2015-06-01

    We consider the timelike version of warped anti-de Sitter space (WAdS), which corresponds to the three-dimensional section of the Gödel solution of four-dimensional cosmological Einstein equations. This geometry presents closed timelike curves (CTCs), which are inherited from its four-dimensional embedding. In three dimensions, this type of solution can be supported without matter provided the graviton acquires mass. Here, among the different ways to consistently give mass to the graviton in three dimensions, we consider the parity-even model known as new massive gravity (NMG). In the bulk of timelike WAdS3 space, we introduce defects that, from the three-dimensional point of view, represent spinning massive particlelike objects. For this type of source, we investigate the definition of quasilocal gravitational energy as seen from infinity, far beyond the region where the CTCs appear. We also consider the covariant formalism applied to NMG to compute the mass and the angular momentum of spinning particlelike defects and compare the result with the one obtained by means of the quasilocal stress tensor. We apply these methods to special limits in which the WAdS3 solutions coincide with locally AdS3 and locally AdS2×R spaces. Finally, we make some comments about the asymptotic symmetry algebra of asymptotically WAdS3 spaces in NMG.

  8. Primordial fluctuations from complex AdS saddle points

    NASA Astrophysics Data System (ADS)

    Hertog, Thomas; van der Woerd, Ellen

    2016-02-01

    One proposal for dS/CFT is that the Hartle-Hawking (HH) wave function in the large volume limit is equal to the partition function of a Euclidean CFT deformed by various operators. All saddle points defining the semiclassical HH wave function in cosmology have a representation in which their interior geometry is part of a Euclidean AdS domain wall with complex matter fields. We compute the wave functions of scalar and tensor perturbations around homogeneous isotropic complex saddle points, turning on single scalar field matter only. We compare their predictions for the spectra of CMB perturbations with those of a different dS/CFT proposal based on the analytic continuation of inflationary universes to real asymptotically AdS domain walls. We find the predictions of both bulk calculations agree to first order in the slow roll parameters, but there is a difference at higher order which, we argue, is a signature of the HH state of the fluctuations.

  9. Transplantation and differentiation of donor cells in the cloned pigs

    SciTech Connect

    Shimada, Arata; Tomii, Ryo; Kano, Koichiro; Nagashima, Hiroshi . E-mail: hnagas@isc.meiji.ac.jp

    2006-06-02

    The application of nuclear transfer technology is an interesting approach to investigate stem and progenitor cell transplantation therapy. If stem cells are used as a nuclear donor, donor cells can engraft into cloned animals without histocompatible problems. However, it is still uncertain whether donor cells can engraft to cloned animal and differentiate in vivo. To address this problem, we transplanted donor cells to dermal tissues of cloned pigs developed by using preadipocytes as donor cells. Preadipocytes are adipocytic progenitor which can differentiate to mature adipocytes in vitro. We showed that the donor preadipocytes were successfully transplanted into the cloned pigs without immune rejection and they differentiated into mature adipocytes in vivo 3 weeks after transplantation. In contrast, allogenic control preadipocytes, which can differentiate in vitro, did not differentiate in vivo. These results indicate that donor progenitor cells can differentiate in cloned animal.

  10. Overextended Criteria Donors: Experience of an Italian Transplantation Center.

    PubMed

    Nure, E; Lirosi, M C; Frongillo, F; Bianco, G; Silvestrini, N; Fiorillo, C; Sganga, G; Agnes, S

    2015-09-01

    The increasing gap between the number of patients who could benefit from liver transplantation and the number of available donors has fueled efforts to maximize the donor pool using marginal grafts that usually were discarded for transplantation. This study included data of all patients who received decreased donor liver grafts between January 2004 and January 2013 (n = 218) with the use of a prospectively collected database. Patients with acute liver failure, retransplantation, pediatric transplantation, and split liver transplantation were excluded. Donors were classified as standard donor (SD), extended criteria donor (ECD), and overextended criteria donor (OECD). The primary endpoints of the study were early allograft primary dysfunction (PDF), primary nonfunction (PNF), and patient survival (PS), whereas incidence of major postoperative complications was the secondary endpoint. In our series we demonstrated that OECD have similar outcome in terms of survival and incidence of complication after liver transplantation as ideal grafts. PMID:26361653

  11. Hydrogen environment embrittlement

    NASA Technical Reports Server (NTRS)

    Gray, H. R.

    1972-01-01

    Hydrogen embrittlement is classified into three types: internal reversible hydrogen embrittlement, hydrogen reaction embrittlement, and hydrogen environment embrittlement. Characteristics of and materials embrittled by these types of hydrogen embrittlement are discussed. Hydrogen environment embrittlement is reviewed in detail. Factors involved in standardizing test methods for detecting the occurrence of and evaluating the severity of hydrogen environment embrittlement are considered. The effect of test technique, hydrogen pressure, purity, strain rate, stress concentration factor, and test temperature are discussed. Additional research is required to determine whether hydrogen environment embrittlement and internal reversible hydrogen embrittlement are similar or distinct types of embrittlement.

  12. Intramolecular Hydrogen Bonding in Substituted Aminoalcohols.

    PubMed

    Lane, Joseph R; Schrøder, Sidsel D; Saunders, Graham C; Kjaergaard, Henrik G

    2016-08-18

    The qualifying features of a hydrogen bond can be contentious, particularly where the hydrogen bond is due to a constrained intramolecular interaction. Indeed there is disagreement within the literature whether it is even possible for an intramolecular hydrogen bond to form between functional groups on adjacent carbon atoms. This work considers the nature of the intramolecular interaction between the OH (donor) and NH2 (acceptor) groups of 2-aminoethanol, with varying substitution at the OH carbon. Gas-phase vibrational spectra of 1-amino-2-methyl-2-propanol (BMAE) and 1-amino-2,2-bis(trifluoromethyl)-2-ethanol (BFMAE) were recorded using Fourier transform infrared spectroscopy and compared to literature spectra of 2-aminoethanol (AE). Based on the experimental OH-stretching frequencies, the strength of the intramolecular hydrogen bond appears to increase from AE < BMAE ≪ BFMAE. Non-covalent interaction analysis shows evidence of an intramolecular hydrogen bond in all three molecules, with the order of the strength of interaction matching that of experiment. The experimental OH-stretching vibrational frequencies were found to correlate well with the calculated kinetic energy density, suggesting that this approach can be used to estimate the strength of an intramolecular hydrogen bond. PMID:27447952

  13. Influence of coagulation factor x on in vitro and in vivo gene delivery by adenovirus (Ad) 5, Ad35, and chimeric Ad5/Ad35 vectors.

    PubMed

    Greig, Jenny A; Buckley, Suzanne Mk; Waddington, Simon N; Parker, Alan L; Bhella, David; Pink, Rebecca; Rahim, Ahad A; Morita, Takashi; Nicklin, Stuart A; McVey, John H; Baker, Andrew H

    2009-10-01

    The binding of coagulation factor X (FX) to the hexon of adenovirus (Ad) 5 is pivotal for hepatocyte transduction. However, vectors based on Ad35, a subspecies B Ad, are in development for cancer gene therapy, as Ad35 utilizes CD46 (which is upregulated in many cancers) for transduction. We investigated whether interaction of Ad35 with FX influenced vector tropism using Ad5, Ad35, and Ad5/Ad35 chimeras: Ad5/fiber(f)35, Ad5/penton(p)35/f35, and Ad35/f5. Surface plasmon resonance (SPR) revealed that Ad35 and Ad35/f5 bound FX with approximately tenfold lower affinities than Ad5 hexon-containing viruses, and electron cryomicroscopy (cryo-EM) demonstrated a direct Ad35 hexon:FX interaction. The presence of physiological levels of FX significantly inhibited transduction of vectors containing Ad35 fibers (Ad5/f35, Ad5/p35/f35, and Ad35) in CD46-positive cells. Vectors were intravenously administered to CD46 transgenic mice in the presence and absence of FX-binding protein (X-bp), resulting in reduced liver accumulation for all vectors. Moreover, Ad5/f35 and Ad5/p35/f35 efficiently accumulated in the lung, whereas Ad5 demonstrated poor lung targeting. Additionally, X-bp significantly reduced lung genome accumulation for Ad5/f35 and Ad5/p35/f35, whereas Ad35 was significantly enhanced. In summary, vectors based on the full Ad35 serotype will be useful vectors for selective gene transfer via CD46 due to a weaker FX interaction compared to Ad5. PMID:19603000

  14. Donor-dependent Extent of Uranium Reduction for Bioremediation of Contaminated Sediment Microcosms

    SciTech Connect

    Palumbo, Anthony Vito; Ravel, Bruce; Phelps, Tommy Joe; Schadt, Christopher Warren; Brandt, Craig C

    2009-01-01

    Bioremediation of uranium was investigated in microcosm experiments containing contaminated sediments from Oak Ridge, Tennessee to explore the importance of electron donor selection for uranium reduction rate and extent. In these experiments, all of the electron donors, including ethanol, glucose, methanol, and methanol with added humic acids, stimulated the reduction and immobilization of aqueous uranium by the indigenous microbial community. Uranium loss from solution began after the completion of nitrate reduction but essentially concurrent with sulfate reduction. When electron donor concentrations were normalized for their equivalent electron donor potential yield, the rates of uranium reduction were nearly equivalent for all treatments (0.55-0.95 {micro}mol L{sup -1} d{sup -1}). Uranium reduction with methanol proceeded after a 15-d longer lag time relative to that of ethanol or glucose. Significant differences were not found with the inclusion of humic acids. The extent of U reduction in sediment slurries measured by XANES at various time periods after the start of the experiment increased in the order of ethanol (5-7% reduced at 77 and 153 d), glucose (49% reduced at 53 d), and methanol (93% reduced at 90 d). The microbial diversity of ethanol- and methanol-amended microcosms in their late stage of U reduction was analyzed with 16S rRNA gene amplification. Members of the Geobacteraceae were found in all microcosms as well as other potential uranium-reducing organisms, such as Clostridium and Desulfosporosinus. The effectiveness of methanol relative to ethanol at reducing aqueous and sediment-hosted uranium suggests that bioremediation strategies that encourage fermentative poising of the subsurface to a lower redox potential may be more effective for long-term uranium immobilization as compared with selecting an electron donor that is efficiently metabolized by known uranium-reducing microorganisms.

  15. Donor-dependent Extent of Uranium Reduction for Bioremediation of Contaminated Sediment Microcosms

    SciTech Connect

    Madden, Andrew S.; Palumbo, Anthony V.; Ravel, Bruce; Vishnivetskaya, Tatiana A.; Phelps, Tommy J.; Schadt, Christopher W.; Brandt, Craig C.

    2009-03-16

    Bioremediation of uranium was investigated in microcosm experiments containing contaminated sediments from Oak Ridge, Tennessee to explore the importance of electron donor selection for uranium reduction rate and extent. In these experiments, all of the electron donors, including ethanol, glucose, methanol, and methanol with added humic acids, stimulated the reduction and immobilization of aqueous uranium by the indigenous microbial community. Uranium loss from solution began after the completion of nitrate reduction but essentially concurrent with sulfate reduction. When electron donor concentrations were normalized for their equivalent electron donor potential yield, the rates of uranium reduction were nearly equivalent for all treatments (0.55-0.95 {micro}mol L{sup -1} d{sup -1}). Uranium reduction with methanol proceeded after a 15-d longer lag time relative to that of ethanol or glucose. Significant differences were not found with the inclusion of humic acids. The extent of U reduction in sediment slurries measured by XANES at various time periods after the start of the experiment increased in the order of ethanol (5-7% reduced at 77 and 153 d), glucose (49% reduced at 53 d), and methanol (93% reduced at 90 d). The microbial diversity of ethanol- and methanol-amended microcosms in their late stage of U reduction was analyzed with 16S rRNA gene amplification. Members of the Geobacteraceae were found in all microcosms as well as other potential uranium-reducing organisms, such as Clostridium and Desulfosporosinus. The effectiveness of methanol relative to ethanol at reducing aqueous and sediment-hosted uranium suggests that bioremediation strategies that encourage fermentative poising of the subsurface to a lower redox potential may be more effective for long-term uranium immobilization as compared with selecting an electron donor that is efficiently metabolized by known uranium-reducing microorganisms.

  16. Plasmid Transfer between Spatially Separated Donor and Recipient Bacteria in Earthworm-Containing Soil Microcosms

    PubMed Central

    Daane, L. L.; Molina, J.; Sadowsky, M. J.

    1997-01-01

    Most gene transfer studies have been performed with relatively homogeneous soil systems in the absence of soil macrobiota, including invertebrates. In this study we examined the influence of earthworm activity (burrowing, casting, and feeding) on transfer of plasmid pJP4 between spatially separated donor (Alcaligenes eutrophus) and recipient (Pseudomonas fluorescens) bacteria in nonsterile soil columns. A model system was designed such that the activity of earthworms would act to mediate cell contact and gene transfer. Three different earthworm species (Aporrectodea trapezoides, Lumbricus rubellus, and Lumbricus terrestris), representing each of the major ecological categories (endogeic, epigeic, and anecic), were evaluated. Inoculated soil microcosms, with and without added earthworms, were analyzed for donor, recipient, and transconjugant bacteria at 5-cm-depth intervals by using selective plating techniques. Transconjugants were confirmed by colony hybridization with a mer gene probe. The presence of earthworms significantly increased dispersal of the donor and recipient strains. In situ gene transfer of plasmid pJP4 from A. eutrophus to P. fluorescens was detected only in earthworm-containing microcosms, at a frequency of (symbl)10(sup2) transconjugants per g of soil. The depth of recovery was dependent on the burrowing behavior of each earthworm species; however, there was no significant difference in the total number of transconjugants among the earthworm species. Donor and recipient bacteria were recovered from earthworm feces (casts) of all three earthworm species, with numbers up to 10(sup6) and 10(sup4) bacteria per g of cast, respectively. A. trapezoides egg capsules (cocoons) formed in the inoculated soil microcosms contained up to 10(sup7) donor and 10(sup6) recipient bacteria per g of cocoon. No transconjugant bacteria, however, were recovered from these microhabitats. To our knowledge, this is the first report of gene transfer between physically

  17. Attitudes towards disclosure and relationship to donor offspring among a national cohort of identity-release oocyte and sperm donors

    PubMed Central

    Lampic, C.; Skoog Svanberg, A.; Sydsjö, G.

    2014-01-01

    STUDY QUESTION What are oocyte donors and sperm donors' attitudes towards disclosure and relationship to donor offspring? SUMMARY ANSWER Oocyte and sperm donors in an identity-release donor programme support disclosure to donor offspring and have overall positive or neutral attitudes towards future contact with offspring. WHAT IS KNOWN ALREADY There is a global trend towards open-identity gamete donation with an increasing number of countries introducing legislation allowing only identifiable donors. While women and men who enrol in identity-release donor programmes accept that they may be contacted by donor offspring, there is limited knowledge of their attitudes towards disclosure to donor offspring and how they perceive their relationship to potential donor offspring. STUDY DESIGN, SIZE AND DURATION The present study is part of the ‘Swedish study on gamete donation’, a prospective cohort study including donors at all fertility clinics performing donation treatment in Sweden. During a 3-year period (2005–2008), donors were recruited consecutively and a total of 157 oocyte donors and 113 sperm donors (who did not donate to a specific ‘known’ couple) were included prior to donation. Participants in the present study include 125 female (80%) and 80 male donors (71%) that completed two follow-up assessments. PARTICIPANTS/MATERIALS, SETTINGS AND METHODS Participants completed two postal questionnaires 2 months after donation and 14 months after donation. Attitudes towards disclosure to donor offspring were assessed with an established instrument. Perceptions of involvement with donor offspring and need for counselling was assessed with study-specific instruments. Statistical analyses were performed with non-parametric tests. MAIN RESULTS AND THE ROLE OF CHANCE A majority of oocyte and sperm donors supported disclosure to donor offspring (71–91%) and had positive or neutral attitudes towards future contact with offspring (80–87%). Sperm donors reported a

  18. Hydrogen permeation through coated and uncoated WASPALOY

    NASA Astrophysics Data System (ADS)

    Perng, T. P.; Johnson, M. J.; Altstetter, C. J.

    1988-05-01

    Hydrogen permeability, diffusivity, and solubility have been measured for a Ni-base superalloy, WASPALOY,* over the temperature range of 200 to 560 °C. Measurements were made with various surface conditions. The hydrogen diffusivity and permeability values for Pd-coated WASPALOY were between those for pure nickel and for austenitic stainless steel. Hydrogen in uncoated WASPALOY had consistently lower effective diffusivity and permeability than in the Pd-coated condition. Gold-plating on WASPALOY or adding H2O to H2 gas substantially reduced both transport parameters, presumably due to slower surface or interface kinetics and lower permeability of hydrogen in the gold layer. Independently measured hydrogen solubility determined by equilibration of bulk specimens with H2 gas was roughly 60 pct of the solubility obtained by dividing the effective diffusivity into the permeation constant. This is discussed on the basis of internal trapping, which reduced the effective diffusivity and resulted in a higher apparent solubility.

  19. Adding value to your work.

    PubMed

    Chambers, D W

    1998-01-01

    Dentists and many staff enjoy characteristics of work associated with high levels of satisfaction and performance. Although value can be added to oral health care professionals' jobs through enlargement, enrichment, rotations, and autonomous work groups, there are limits to these techniques. Controlling work performance by means of rewards is risky. Probably the most effective means of adding value to jobs is through the Quality of Work Life approach, concentrating on job design and placement to make work meaningful and autonomous and to provide feedback. PMID:9697373

  20. Biomimetic Production of Hydrogen

    NASA Astrophysics Data System (ADS)

    Gust, Devens

    2004-03-01

    The basic reaction for hydrogen generation is formation of molecular hydrogen from two electrons and two protons. Although there are many possible sources for the protons and electrons, and a variety of mechanisms for providing the requisite energy for hydrogen synthesis, the most abundant and readily available source of protons and electrons is water, and the most attractive source of energy for powering the process is sunlight. Not surprisingly, living systems have evolved to take advantage of these sources for materials and energy. Thus, biology provides paradigms for carrying out the reactions necessary for hydrogen production. Photosynthesis in green plants uses sunlight as the source of energy for the oxidation of water to give molecular oxygen, protons, and reduction potential. Some photosynthetic organisms are capable of using this reduction potential, in the form of the reduced redox protein ferredoxin, to reduce protons and produce molecular hydrogen via the action of an hydrogenase enzyme. A variety of other organisms metabolize the reduced carbon compounds that are ultimately the major products of photosynthesis to produce molecular hydrogen. These facts suggest that it might be possible to use light energy to make molecular hydrogen via biomimetic constructs that employ principles similar to those used by natural organisms, or perhaps with hybrid "bionic" systems that combine biomimetic materials with natural enzymes. It is now possible to construct artificial photosynthetic systems that mimic some of the major steps in the natural process.(1) Artificial antennas based on porphyrins, carotenoids and other chromophores absorb light at various wavelengths in the solar spectrum and transfer the harvested excitation energy to artificial photosynthetic reaction centers.(2) In these centers, photoinduced electron transfer uses the energy from light to move an electron from a donor to an acceptor moiety, generating a high-energy charge-separated state

  1. Universal prediction of intramolecular hydrogen bonds in organic crystals.

    PubMed

    Galek, Peter T A; Fábián, László; Allen, Frank H

    2010-04-01

    A complete exploration of intramolecular hydrogen bonds (IHBs) has been undertaken using a combination of statistical analyses of the Cambridge Structural Database and computation of ab initio interaction energies for prototypical hydrogen-bonded fragments. Notable correlations have been revealed between computed energies, hydrogen-bond geometries, donor and acceptor chemistry, and frequencies of occurrence. Significantly, we find that 95% of all observed IHBs correspond to the five-, six- or seven-membered rings. Our method to predict a propensity for hydrogen-bond occurrence in a crystal has been adapted for such IHBs, applying topological and chemical descriptors derived from our findings. In contrast to intermolecular hydrogen bonding, it is found that IHBs can be predicted across the complete chemical landscape from a single optimized probability model, which is presented. Predictivity of 85% has been obtained for generic organic structures, which can exceed 90% for discrete classes of IHB. PMID:20305358

  2. Hydrogen bonding of water-ethanol in alcoholic beverages.

    PubMed

    Nose, Akira; Hojo, Masashi

    2006-10-01

    An alcoholic beverage is a type of water-ethanol solution with flavor and taste. The properties of the hydrogen bonding of water-ethanol in alcoholic beverages have not been clarified sufficiently. We investigated factors that could affect the hydrogen-bonding structure of water-ethanol on the basis of proton nuclear magnetic resonance (1H NMR) chemical shifts of the OH of water-ethanol and Raman OH stretching spectra. Not only acids (H+ and HA: undissociated acids) but also bases (OH- and A-: conjugate-base anions from weak acids) strengthened the hydrogen-bonding structure of water-ethanol. It was also demonstrated that the hydrogen bonding is strengthened by chemical components in alcoholic beverages (whiskey, Japanese sake, shochu). It can be suggested that hydrogen-bonding donors as well as acceptors in alcohol beverages, which exist as the initial components or are gained later on, should cause the tight association between water and ethanol molecules. PMID:17116572

  3. Hydrogen sulfide and translational medicine

    PubMed Central

    Guo, Wei; Cheng, Ze-yu; Zhu, Yi-zhun

    2013-01-01

    Hydrogen sulfide (H2S) along with carbon monoxide and nitric oxide is an important signaling molecule that has undergone large numbers of fundamental investigations. H2S is involved in various physiological activities associated with the regulation of homeostasis, vascular contractility, pro- and anti-inflammatory activities, as well as pro- and anti-apoptotic activities etc. However, the actions of H2S are influenced by its concentration, reaction time, and cell/disease types. Therefore, H2S is a signaling molecule without definite effect. The use of existing H2S donors is limited because of the instant release and short lifetime of H2S. Thus, translational medicine involving the sustained and controlled release of H2S is of great value for both scientific and clinical uses. H2S donation can be manipulated by different ways, including where H2S is given, how H2S is donated, or the specific structures of H2S-releasing drugs and H2S donor molecules. This review briefly summarizes recent progress in research on the physiological and pathological functions of H2S and H2S-releasing drugs, and suggests hope for future investigations. PMID:24096643

  4. Blood donors on teratogenic drugs and donor deferral periods in a clinical situation.

    PubMed

    Shin, S Y; Shin, Y H; Lee, S W; Shin, J Y; Kim, C H

    2012-05-01

    Deferral of blood donors taking teratogenic drugs is critical. From March 2008 to January 2009, we analysed stored blood specimens from donors who had taken teratogenic drugs and whose blood was transfused to women of childbearing age to determine the plasma concentration at the time of donation using high-performance liquid chromatography. In total, 167 specimens were examined. The numbers of specimens exceeding the quantification limit were 7, 39, 4, 2 and 1 for finasteride, isotretinoin, acitretin, etretinate and dutasteride, respectively. Finasteride was beyond the recommended drug deferral period in one specimen. These results may help create practical deferral policies. PMID:22211799

  5. Hydrogen detector

    DOEpatents

    Kanegae, Naomichi; Ikemoto, Ichiro

    1980-01-01

    A hydrogen detector of the type in which the interior of the detector is partitioned by a metal membrane into a fluid section and a vacuum section. Two units of the metal membrane are provided and vacuum pipes are provided independently in connection to the respective units of the metal membrane. One of the vacuum pipes is connected to a vacuum gauge for static equilibrium operation while the other vacuum pipe is connected to an ion pump or a set of an ion pump and a vacuum gauge both designed for dynamic equilibrium operation.

  6. Photocatalytic decomposition of humic acids in anoxic aqueous solutions producing hydrogen, oxygen and light hydrocarbons.

    PubMed

    Klauson, Deniss; Budarnaja, Olga; Beltran, Ignacio Castellanos; Krichevskaya, Marina; Preis, Sergei

    2014-01-01

    Photocatalytic water splitting for hydrogen and oxygen production requires sacrificial electron donors, for example, organic compounds. Titanium dioxide catalysts doped with platinum, cobalt, tungsten, copper and iron were experimentally tested for the production of hydrogen, oxygen and low molecular weight hydrocarbons from aqueous solutions of humic substances (HS). Platinum-doped catalyst showed the best results in hydrogen generation, also producing methane, ethene and ethane, whereas the best oxygen production was exhibited by P25, followed by copper--and cobalt-containing photocatalysts. Iron-containing photocatalyst produced carbon monoxide as a major product. HS undergoing anoxic photocatalytic degradation produce hydrogen with minor hydrocarbons, and/or oxygen. It appears that better hydrogen yield is achieved when direct HS splitting takes place, as opposed to HS acting as electron donors for water splitting. PMID:25145176

  7. Donor Rejection Before Living Donor Liver Transplantation: Causes and Cost Effective Analysis in an Egyptian Transplant Center.

    PubMed Central

    El-Meteini, Mahmoud; Dabbous, Hany; Sakr, Mohammad; Ibrahim, Amany; Fawzy, Iman; Bahaa, Mohamed; Abdelaal, Amr; Fathy, Mohamed; Said, Hany; Rady, Mohamed; El-Dorry, Ahmed

    2014-01-01

    Background: In the living donor liver transplant setting, the preoperative assessment of potential donors is important to ensure the donor safety. Objectives: The aim of this study was to identify causes and costs of living liver-donors rejection in the donation process. Materials and Methods: From June 2010 to June 2012, all potential living liver donors for 66 liver transplant candidates were screened at the Ain Shams Center for Organ Transplantation. Potential donors were evaluated in 3 phases, and their data were reviewed to determine the causes and at which phase the donors were rejected. Results: One hundred and ninety two potential living liver donors, including 157 (81.7%) males, were screened for 66 potential recipients. Of these, 126 (65.6%) were disqualified for the donation. The causes of rejection were classified as surgical (9.5 %) or medical (90.5 %). Five donors (3.9 %) were rejected due to multiple causes. Factor V Leiden mutation was detected in 29 (23 %) rejected donors (P = 0.001), 25 (19.8 %) donors had positive results for hepatitis serology (P = 0.005), and 16 (12.7 %) tested positive for drug abuse. Portal vein trifurcation (n = 9, 7.1%) and small size liver graft estimated by CT volumetric analysis (n = 6, 4.8 %) were the main surgical causes which precluded the donation. Conclusions: Among potential Egyptian living liver donors, Factor V Leiden mutation was a significant cause for live donor rejection. A stepwise approach to donor assessment was found to be cost-effective. PMID:24497879

  8. Nutritional management of the donor cow.

    PubMed

    Santos, J E P; Cerri, R L A; Sartori, R

    2008-01-01

    Nutrition of the donor cow can influence oocyte and embryo quality, which can affect the success of embryo transfer. Severe undernutrition compromised ovarian follicular development, with implications for superovulatory response and embryo quality. In postpartum lactating cows, undernutrition or inability to consume sufficient nutrients delayed resumption of ovulation, reduced the number of follicles, and compromised oocyte quality. Moderate undernutrition of nonlactating cows was unlikely to affect embryo quality; conversely, nonlactating animals on maintenance diets usually had better superovulatory responses and improved oocyte competence and embryo quality. The negative effects of overfeeding are thought to be mediated by alterations in endocrine cues, such as hyperinsulinemia and increased glucose and IGF-I, which may interfere with glucose transport in the embryo and increase apoptosis. Manipulating energy sources such as carbohydrates and fatty acids (FA) may influence embryo viability, but the effects of FA were not consistent in vitro; increasing concentrations of unsaturated FA in follicular and embryonic cells usually improved embryo viability and resistance to cryopreservation. Excess protein intake and increased urea and ammonia in body fluids can be toxic to embryos, impairing their development; these effects seemed to be associated with alterations in uterine pH and granulosa cell function. Likewise, toxins in feeds (e.g. gossypol), reduced embryo development and increased pregnancy losses. Diet of donor cows should be formulated to optimize the supply of nutrients to meet needs; however, manipulating energy intake, source of FA and protein content of donor diets, particularly moderate underfeeding in nonlactating cows, may further optimize responses. PMID:17959235

  9. Dissociation between peripheral blood chimerism and tolerance to hindlimb composite tissue transplants: preferential localization of chimerism in donor bone

    PubMed Central

    Rahhal, Dina N.; Xu, Hong; Huang, Wei-Chao; Wu, Shengli; Wen, Yujie; Huang, Yiming; Ildstad, Suzanne T.

    2009-01-01

    Background Mixed chimerism induces donor-specific tolerance to composite tissue allotransplants (CTA). In the present studies, we used a nonmyeloablative conditioning approach to establish chimerism and promote CTA acceptance. Methods WF (RT1Au) rats were conditioned with 600-300 cGy total body irradiation (TBI, day-1), 100 × 106 T cell-depleted ACI (RT1Aabl) bone marrow cells were transplanted day 0, followed by a 11-day course of tacrolimus and one dose of anti-lymphocyte serum (day 10). Heterotopic osteomyocutaneous flap transplantation was performed 4-6 weeks after bone marrow transplantation. Results Mixed chimerism was initially achieved in almost all recipients, but long-term acceptance of CTA was only achieved in rats treated with 600 cGy TBI. When anti-αβ-TCR mAb (day-3) was added into the regimens, donor chimerism was similar to recipients preconditioned without anti-αβ-TCR mAb. However, the long-term CTA survival was significantly improved in chimeras receiving ≥ 300 cGy TBI plus anti-αβ-TCR mAb. Higher levels of donor chimerism were associated with CTA acceptance. The majority of flap-acceptors lost peripheral blood (PB) chimerism within 6 months. However, donor chimerism persisted in transplanted bone at significantly higher levels compared to other hematopoietic compartments. The compartment donor chimerism may be responsible for the maintenance of tolerance to CTA. Long-term acceptors were tolerant to a donor skin graft challenge even in the absence of PB chimerism. Conclusions Mixed chimerism established by nonmyeloablative conditioning induces long-term acceptance of CTA which is associated with persistent chimerism preferentially in transplanted donor bone. PMID:19920776

  10. Hydrogen production from salt water by Marine blue green algae and solar radiation

    NASA Technical Reports Server (NTRS)

    Mitsui, A.; Rosner, D.; Kumazawa, S.; Barciela, S.; Phlips, E.

    1985-01-01

    Two marine bluegreen algae, Oscillatoria sp. Miami BG 7 and Synechococcus sp Miami 041511 have been selected as the result of over 10 years continuous and intensive effort of isolation, growth examination, and the screening of hydrogen photoproduction capability in this laboratory. Both strains photoproduced hydrogen for several days at high rates and a quantity of hydrogen was accumulated in a closed vessel. Overall hydrogen donor substance of the hydrogen photoproduction was found to be salt water. Using strain Miami BG 7, a two step method of hydrogen photoproduction from salt water was successfully developed and this was recycled several times over a one month period using both free cells and immobilized cells in both indoor and outdoor under natural sunlight. According to these experiments, a prototype floating hydrogen production system was designed for further development of the biosolar hydrogen production system.

  11. The role of hydrogen in semi-insulating InP

    SciTech Connect

    Han, Y.; Liu, X.; Jiao, J.; Qian, J.; Chen, Y.; Wang, Z.; Lin, L.

    1998-12-31

    Complexes of vacancy at indium site with one to four hydrogen atoms and isolated hydrogen or hydrogen dimer and other infrared absorption lines, tentatively be assigned to hydrogen related defects were investigated by FTIR. Hydrogen can passivate imperfections, thereby eliminating detrimental electronic states from the energy bandgap. Incorporated hydrogen can introduce extended defects and generate electrically-active defects. Hydrogen also can act as an actuator for creating antistructure defects. Isolated hydrogen related defects (e.g., H{sub 2}{sup *}) may play an important role in the conversion of the annealed wafers from semiconducting to the semi-insulating behavior. H{sub 2}{sup *} may be a deep donor, whose energy level is very near the iron deep acceptor level in the energy gap.

  12. Comparison of Epidemiological Methods for Estimation of Hepatitis B Incidence and Residual Risk for Blood Donors in Southern Brazil

    PubMed Central

    Kupek, Emil; Petry, Andrea

    2011-01-01

    Background and Objective. The objective of this work was to compare three methods for estimating hepatitis B virus (HBV) incidence and residual risk. Methods. Computerized blood donor records in southern Brazil were examined for the period 2004–2006. The methods for estimating HBV incidence included stand-alone HBsAg, HBsAg yield method, and an extension of the latter which added recent anti-HBc seroconversions as incident HBV cases. Results. HBV incidences for the above methods were 9.91, 20.09, and 22.93 per 100000 repeat donors, respectively. In the same order, corresponding residual risks were 1 : 62482, 1 : 30821, and 1 : 47559, respectively. First-time donors had 52 higher HBV incidence compared to repeat donors. Conclusion. Although the three methods compared produced overlapping 95% confidence intervals, their variation was considerably lower for the method which included recent anti-HBc seroconversions. First-time donors are primary cause for concern regarding HBV transmission via blood transfusion in southern Brazil. PMID:25346858

  13. Higher-derivative superparticle in AdS3 space

    NASA Astrophysics Data System (ADS)

    Kozyrev, Nikolay; Krivonos, Sergey; Lechtenfeld, Olaf

    2016-03-01

    Employing the coset approach we construct component actions for a superparticle moving in AdS3 with N =(2 ,0 ), D =3 supersymmetry partially broken to N =2 , d =1 . These actions may contain higher time-derivative terms, which are chosen to possess the same (super)symmetries as the free superparticle. In terms of the nonlinear-realization superfields, the component actions always take a simpler form when written in terms of covariant Cartan forms. We also consider in detail the reduction to the nonrelativistic case and construct the corresponding action of a Newton-Hooke superparticle and its higher-derivative generalizations. The structure of these higher time-derivative generalizations is completely fixed by invariance under the supersymmetric Newton-Hooke algebra extended by two central charges.

  14. Aspects of warped AdS3/CFT2 correspondence

    NASA Astrophysics Data System (ADS)

    Chen, Bin; Zhang, Jia-Ju; Zhang, Jian-Dong; Zhong, De-Liang

    2013-04-01

    In this paper we apply the thermodynamics method to investigate the holographic pictures for the BTZ black hole, the spacelike and the null warped black holes in three-dimensional topologically massive gravity (TMG) and new massive gravity (NMG). Even though there are higher derivative terms in these theories, the thermodynamics method is still effective. It gives consistent results with the ones obtained by using asymptotical symmetry group (ASG) analysis. In doing the ASG analysis we develop a brute-force realization of the Barnich-Brandt-Compere formalism with Mathematica code, which also allows us to calculate the masses and the angular momenta of the black holes. In particular, we propose the warped AdS3/CFT2 correspondence in the new massive gravity, which states that quantum gravity in the warped spacetime could holographically dual to a two-dimensional CFT with {c_R}={c_L}=24 /{Gm{β^2√{{2( {21-4{β^2}} )}}}}.

  15. Thermodynamics of charged Lovelock: AdS black holes

    NASA Astrophysics Data System (ADS)

    Prasobh, C. B.; Suresh, Jishnu; Kuriakose, V. C.

    2016-04-01

    We investigate the thermodynamic behavior of maximally symmetric charged, asymptotically AdS black hole solutions of Lovelock gravity. We explore the thermodynamic stability of such solutions by the ordinary method of calculating the specific heat of the black holes and investigating its divergences which signal second-order phase transitions between black hole states. We then utilize the methods of thermodynamic geometry of black hole spacetimes in order to explain the origin of these points of divergence. We calculate the curvature scalar corresponding to a Legendre-invariant thermodynamic metric of these spacetimes and find that the divergences in the black hole specific heat correspond to singularities in the thermodynamic phase space. We also calculate the area spectrum for large black holes in the model by applying the Bohr-Sommerfeld quantization to the adiabatic invariant calculated for the spacetime.

  16. Vortex hair on AdS black holes

    NASA Astrophysics Data System (ADS)

    Gregory, Ruth; Gustainis, Peter C.; Kubizňák, David; Mann, Robert B.; Wills, Danielle

    2014-11-01

    We analyse vortex hair for charged rotating asymptotically AdS black holes in the abelian Higgs model. We give analytical and numerical arguments to show how the vortex interacts with the horizon of the black hole, and how the solution extends to the boundary. The solution is very close to the corresponding asymptotically flat vortex, once one transforms to a frame that is non-rotating at the boundary. We show that there is a Meissner effect for extremal black holes, with the vortex flux being expelled from sufficiently small black holes. The phase transition is shown to be first order in the presence of rotation, but second order without rotation. We comment on applications to holography.

  17. An investigation of AdS2 backreaction and holography

    NASA Astrophysics Data System (ADS)

    Engelsöy, Julius; Mertens, Thomas G.; Verlinde, Herman

    2016-07-01

    We investigate a dilaton gravity model in AdS2 proposed by Almheiri and Polchinski [1] and develop a 1d effective description in terms of a dynamical boundary time with a Schwarzian derivative action. We show that the effective model is equivalent to a 1d version of Liouville theory, and investigate its dynamics and symmetries via a standard canonical framework. We include the coupling to arbitrary conformal matter and analyze the effective action in the presence of possible sources. We compute commutators of local operators at large time separation, and match the result with the time shift due to a gravitational shockwave interaction. We study a black hole evaporation process and comment on the role of entropy in this model.

  18. Potential donor segregation to promote blood donation.

    PubMed

    Martín-Santana, Josefa D; Beerli-Palacio, Asunción

    2008-04-01

    This work is set in the field of social marketing and more specifically in the context of blood donation. Its principal objective focuses on segregating potential donors by using the inhibitors or barriers to a blood donation behaviour as criteria. Moreover, an analysis of the predisposition to donate blood, the intrinsic and extrinsic motivations for donating blood, and the incentives that may stimulate their donation conduct was conducted for each of the four identified groups. The results reveal that the four segments differ significantly in their predisposition to donate, in their motivations and in the incentives that encourage them to donate blood. PMID:18343199

  19. Embryo Transfer (Techniques, Donors, and Recipients).

    PubMed

    Phillips, Patrick E; Jahnke, Marianna M

    2016-07-01

    Commercial embryo transfer has evolved as an art and as a science since the early 1970s. Today's multiple ovulation embryo transfer is a widely used reproductive tool on many farms and is performed by veterinarians throughout the world. Propagation of the female genomes of select donors, through embryo transfer, has allowed a rapid progression of genetic gain in many breeds, much like what happened with artificial insemination since the 1940s. Advancement of this technology is migrating to in vitro fertilization technology today, allowing a higher volume of offspring to be produced with sex selection in the laboratory. PMID:27140299

  20. Polymerization Initiated by Organic Electron Donors.

    PubMed

    Broggi, Julie; Rollet, Marion; Clément, Jean-Louis; Canard, Gabriel; Terme, Thierry; Gigmes, Didier; Vanelle, Patrice

    2016-05-10

    Polymerization reactions with organic electron donors (OED) as initiators are presented herein. The metal-free polymerization of various activated alkene and cyclic ester monomers was performed in short reaction times, under mild conditions, with small amounts of organic reducing agents, and without the need for co-initiators or activation by photochemical, electrochemical, or other methods. Hence, OED initiators enabled the development of an efficient, rapid, room-temperature process that meets the technical standards expected for industrial processes, such as energy savings, cost-effectiveness and safety. Mechanistic investigations support an electron-transfer initiation pathway that leads to the reduction of the monomer. PMID:27061743

  1. How important is donor age in liver transplantation?

    PubMed

    Lué, Alberto; Solanas, Estela; Baptista, Pedro; Lorente, Sara; Araiz, Juan J; Garcia-Gil, Agustin; Serrano, M Trinidad

    2016-06-01

    The age of liver donors has been increasing in the past several years because of a donor shortage. In the United States, 33% of donors are age 50 years or older, as are more than 50% in some European countries. The impact of donor age on liver transplantation (LT) has been analyzed in several studies with contradictory conclusions. Nevertheless, recent analyses of the largest databases demonstrate that having an older donor is a risk factor for graft failure. Donor age is included as a risk factor in the more relevant graft survival scores, such as the Donor Risk Index, donor age and Model for End-stage Liver Disease, Survival Outcomes Following Liver Transplantation, and the Balance of Risk. The use of old donors is related to an increased rate of biliary complications and hepatitis C virus-related graft failure. Although liver function does not seem to be significantly affected by age, the incidence of several liver diseases increases with age, and the capacity of the liver to manage or overcome liver diseases or external injuries decreases. In this paper, the importance of age in LT outcomes, the role of donor age as a risk factor, and the influence of aging on liver regeneration are reviewed. PMID:27275089

  2. How important is donor age in liver transplantation?

    PubMed Central

    Lué, Alberto; Solanas, Estela; Baptista, Pedro; Lorente, Sara; Araiz, Juan J; Garcia-Gil, Agustin; Serrano, M Trinidad

    2016-01-01

    The age of liver donors has been increasing in the past several years because of a donor shortage. In the United States, 33% of donors are age 50 years or older, as are more than 50% in some European countries. The impact of donor age on liver transplantation (LT) has been analyzed in several studies with contradictory conclusions. Nevertheless, recent analyses of the largest databases demonstrate that having an older donor is a risk factor for graft failure. Donor age is included as a risk factor in the more relevant graft survival scores, such as the Donor Risk Index, donor age and Model for End-stage Liver Disease, Survival Outcomes Following Liver Transplantation, and the Balance of Risk. The use of old donors is related to an increased rate of biliary complications and hepatitis C virus-related graft failure. Although liver function does not seem to be significantly affected by age, the incidence of several liver diseases increases with age, and the capacity of the liver to manage or overcome liver diseases or external injuries decreases. In this paper, the importance of age in LT outcomes, the role of donor age as a risk factor, and the influence of aging on liver regeneration are reviewed. PMID:27275089

  3. Systematics of Coupling Flows in AdS Backgrounds

    SciTech Connect

    Goldberger, Walter D.; Rothstein, Ira Z.

    2003-03-18

    We give an effective field theory derivation, based on the running of Planck brane gauge correlators, of the large logarithms that arise in the predictions for low energy gauge couplings in compactified AdS}_5 backgrounds, including the one-loop effects of bulk scalars, fermions, and gauge bosons. In contrast to the case of charged scalars coupled to Abelian gauge fields that has been considered previously in the literature, the one-loop corrections are not dominated by a single 4D Kaluza-Klein mode. Nevertheless, in the case of gauge field loops, the amplitudes can be reorganized into a leading logarithmic contribution that is identical to the running in 4D non-Abelian gauge theory, and a term which is not logarithmically enhanced and is analogous to a two-loop effect in 4D. In a warped GUT model broken by the Higgs mechanism in the bulk,we show that the matching scale that appears in the large logarithms induced by the non-Abelian gauge fields is m_{XY}^2/k where m_{XY} is the bulk mass of the XY bosons and k is the AdS curvature. This is in contrast to the UV scale in the logarithmic contributions of scalars, which is simply the bulk mass m. Our results are summarized in a set of simple rules that can be applied to compute the leading logarithmic predictions for coupling constant relations within a given warped GUT model. We present results for both bulk Higgs and boundary breaking of the GUT gauge

  4. Holography beyond conformal invariance and AdS isometry?

    SciTech Connect

    Barvinsky, A. O.

    2015-03-15

    We suggest that the principle of holographic duality be extended beyond conformal invariance and AdS isometry. Such an extension is based on a special relation between functional determinants of the operators acting in the bulk and on its boundary, provided that the boundary operator represents the inverse propagators of the theory induced on the boundary by the Dirichlet boundary value problem in the bulk spacetime. This relation holds for operators of a general spin-tensor structure on generic manifolds with boundaries irrespective of their background geometry and conformal invariance, and it apparently underlies numerous O(N{sup 0}) tests of the AdS/CFT correspondence, based on direct calculation of the bulk and boundary partition functions, Casimir energies, and conformal anomalies. The generalized holographic duality is discussed within the concept of the “double-trace” deformation of the boundary theory, which is responsible in the case of large-N CFT coupled to the tower of higher-spin gauge fields for the renormalization group flow between infrared and ultraviolet fixed points. Potential extension of this method beyond the one-loop order is also briefly discussed.

  5. Holography beyond conformal invariance and AdS isometry?

    NASA Astrophysics Data System (ADS)

    Barvinsky, A. O.

    2015-03-01

    We suggest that the principle of holographic duality be extended beyond conformal invariance and AdS isometry. Such an extension is based on a special relation between functional determinants of the operators acting in the bulk and on its boundary, provided that the boundary operator represents the inverse propagators of the theory induced on the boundary by the Dirichlet boundary value problem in the bulk spacetime. This relation holds for operators of a general spin-tensor structure on generic manifolds with boundaries irrespective of their background geometry and conformal invariance, and it apparently underlies numerous O( N 0) tests of the AdS/CFT correspondence, based on direct calculation of the bulk and boundary partition functions, Casimir energies, and conformal anomalies. The generalized holographic duality is discussed within the concept of the "double-trace" deformation of the boundary theory, which is responsible in the case of large- N CFT coupled to the tower of higher-spin gauge fields for the renormalization group flow between infrared and ultraviolet fixed points. Potential extension of this method beyond the one-loop order is also briefly discussed.

  6. Islands of stability and recurrence times in AdS

    NASA Astrophysics Data System (ADS)

    Green, Stephen R.; Maillard, Antoine; Lehner, Luis; Liebling, Steven L.

    2015-10-01

    We study the stability of anti-de Sitter (AdS) spacetime to spherically symmetric perturbations of a real scalar field in general relativity. Further, we work within the context of the "two time framework" (TTF) approximation, which describes the leading nonlinear effects for small amplitude perturbations, and is therefore suitable for studying the weakly turbulent instability of AdS—including both collapsing and noncollapsing solutions. We have previously identified a class of quasiperiodic (QP) solutions to the TTF equations, and in this paper we analyze their stability. We show that there exist several families of QP solutions that are stable to linear order, and we argue that these solutions represent islands of stability in TTF. We extract the eigenmodes of small oscillations about QP solutions, and we use them to predict approximate recurrence times for generic noncollapsing initial data in the full (non-TTF) system. Alternatively, when sufficient energy is driven to high-frequency modes, as occurs for initial data far from a QP solution, the TTF description breaks down as an approximation to the full system. Depending on the higher order dynamics of the full system, this often signals an imminent collapse to a black hole.

  7. Dynamic Kinetic Resolution Approach for the Asymmetric Synthesis of Tetrahydrobenzodiazepines Using Transfer Hydrogenation by Chiral Phosphoric Acid.

    PubMed

    Horiguchi, Kosaku; Yamamoto, Eri; Saito, Kodai; Yamanaka, Masahiro; Akiyama, Takahiko

    2016-06-01

    Asymmetric synthesis of tetrahydrobenzodiazepines was achieved by transfer hydrogenation of dihydrobenzodiazepines with benzothiazoline having a hydrogen-bonding donor substituent by means of a newly synthesized chiral phosphoric acid. This method was applicable to various racemic dihydrobenzodiazepines to give the corresponding products in good yields with excellent diastereoselectivities and enantioselectivities taking advantage of the dynamic kinetic resolution. Furthermore, the effect of bulky substituent at 3,3'-position on the catalyst and hydrogen-bonding donor substituent on benzothiazoline was fully elucidated by the theoretical study. PMID:27150449

  8. The father of Soviet Hydrogen Bomb

    NASA Astrophysics Data System (ADS)

    Romanov, Yu. A.

    1990-08-01

    The creation of Soviet Hydrogen bomb has been described.The main participants to the Physical and Computational parts of the projects were shown. The "Sloika " part of the Project, concerned to neutrons kinetic has been discussed. The contribution by A.D. Sakharov to main achievements has been ponted out.

  9. The Willed Body Donor Interview Project: Medical Student and Donor Expectations

    ERIC Educational Resources Information Center

    Bohl, Michael; Holman, Alexis; Mueller, Dean A.; Gruppen, Larry D.; Hildebrandt, Sabine

    2013-01-01

    The Anatomical Donations Program at the University of Michigan Medical School (UMMS) has begun a multiphase project wherein interviews of donors will be recorded and later shown to medical students who participate in the anatomical dissection course. The first phase of this project included surveys of both current UMMS medical students and donors…

  10. Effect of Oligomer Length on Photophysical Properties of Platinum Acetylide Donor-Acceptor-Donor Oligomers.

    PubMed

    Cekli, Seda; Winkel, Russell W; Schanze, Kirk S

    2016-07-21

    We report a systematic study that explores how the triplet excited state is influenced by conjugation length in a series of benzothiadiazole units containing donor-acceptor-donor (DAD)-type platinum acetylide oligomers and polymer. The singlet and triplet excited states for the series were characterized by an array of photophysical methods including steady-state luminescence spectroscopy and femtosecond-nanosecond transient absorption spectroscopy. In addition to the experimental work, a computational study using density functional theory was conducted to gain more information about the structure, composition, and energies of the frontier molecular orbitals. It is observed that both the singlet and triplet excited states are mainly localized on a single donor-acceptor-donor unit in the oligomers. Interestingly, it is discovered that the intersystem crossing efficiency increases dramatically in the longer oligomers. The effect is attributed to an enhanced contribution of the heavy metal platinum in the frontier orbitals (HOMO and LUMO), an effect that leads to enhanced spin-orbit coupling. PMID:27291712

  11. 75 FR 58400 - Donor Management Research: Improvements in Clinical Management of Deceased Organ Donors

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-24

    ...The Health Resources and Services Administration (HRSA), Division of Transplantation, is soliciting input, feedback, and suggestions from researchers and interested parties within the organ donation and transplant community regarding guidance for a possible grant or contract that focuses on improvements in clinical management of deceased organ donors. Given the continued imbalance between the......

  12. Tuning the Rainbow: Systematic Modulation of Donor-Acceptor Systems through Donor Substituents and Solvent.

    PubMed

    Larsen, Christopher B; van der Salm, Holly; Shillito, Georgina E; Lucas, Nigel T; Gordon, Keith C

    2016-09-01

    A series of donor-acceptor compounds is reported in which the energy of the triarylamine donor is systematically tuned through para substitution with electron-donating methoxy and electron-withdrawing cyano groups. The acceptor units investigated are benzothiadiazole (btd), dipyridophenazine (dppz), and its [ReCl(CO)3(dppz)] complex. The effect of modulating donor energy on the electronic and photophysical properties is investigated using (1)H NMR spectroscopy, DFT calculations, electrochemistry, electronic absorption and emission spectroscopies, ground state and resonance Raman spectroscopy, and transient absorption spectroscopy. Qualitative correlations between the donor energy and the properties of interest are obtained using Hammett σ(+) constants. Methoxy and cyano groups are shown to destabilize and stabilize, respectively, the frontier molecular orbitals, with the HOMO affected more significantly than the LUMO, narrowing the HOMO-LUMO band gap as the substituent becomes more electron-donating-observable as a bathochromic shift in low-energy charge-transfer absorption bands. Charge-transfer emission bands are also dependent on the electron-donating/withdrawing nature of the substituent, and in combination with the highly solvatochromic nature of charge-transfer states, emission can be tuned to span the entire visible region. PMID:27500590

  13. Functionalized squaraine donors for nanocrystalline organic photovoltaics.

    PubMed

    Wei, Guodan; Xiao, Xin; Wang, Siyi; Sun, Kai; Bergemann, Kevin J; Thompson, Mark E; Forrest, Stephen R

    2012-01-24

    We study a family of functionalized squaraine (fSQ) donors for absorbing in the near-infrared (NIR) and green spectral regions. The NIR-absorbing materials are the symmetric molecules 2,4-bis[4-(N-phenyl-1-naphthylamino)-2,6-dihydroxyphenyl]squaraine (1-NPSQ), 2,4-bis[4-(N,N-diphenylamino)-2,6 dihydroxyphenyl]squaraine, and 2,4-bis[4-(N,N-dipropylamino)-2,6-dihydroxyphenyl]squaraine. The green light absorbing donors are asymmetric squaraines, namely, 2,4-bis[4-(N,N-diphenylamino)-2,6-dihydroxyphenyl]squaraine and 2-[4-(N,N-diisobutylamino)-2,6-dihydroxyphenyl]-4-diphenylamino]squaraine. Substitution of the arylamine groups enhances intermolecular packing, thereby increasing hole transport and the possibility of forming extended nanocrystalline junctions when annealed. Nanocrystalline solar cells based on fSQ and a C(60) acceptor have V(oc) = 1.0 V and fill factors 0.73 ± 0.01. Solar cells incorporating annealed 1-NPSQ films result in a power conversion efficiency of 5.7 ± 0.6% at 1 sun, AM1.5G illumination. PMID:22196154

  14. Evaluation of sustained release polylactate electron donors for removal of hexavalent chromium from contaminated groundwater

    SciTech Connect

    Brodie, E.L.; Joyner, D. C.; Faybishenko, B.; Conrad, M. E.; Rios-Velazquez, C.; Mork, B.; Willet, A.; Koenigsberg, S.; Herman, D.; Firestone, M. K.; Hazen, T. C.; Malave, Josue; Martinez, Ramon

    2011-02-15

    To evaluate the efficacy of bioimmobilization of Cr(VI) in groundwater at the Department of Energy Hanford site, we conducted a series of microcosm experiments using a range of commercial electron donors with varying degrees of lactate polymerization (polylactate). These experiments were conducted using Hanford Formation sediments (coarse sand and gravel) immersed in Hanford groundwater, which were amended with Cr(VI) and several types of lactate-based electron donors (Hydrogen Release Compound, HRC; primer-HRC, pHRC; extended release HRC) and the polylactate-cysteine form (Metal Remediation Compound, MRC). The results showed that polylactate compounds stimulated an increase in bacterial biomass and activity to a greater extent than sodium lactate when applied at equivalent carbon concentrations. At the same time, concentrations of headspace hydrogen and methane increased and correlated with changes in the microbial community structure. Enrichment of Pseudomonas spp. occurred with all lactate additions, and enrichment of sulfate-reducing Desulfosporosinus spp. occurred with almost complete sulfate reduction. The results of these experiments demonstrate that amendment with the pHRC and MRC forms result in effective removal of Cr(VI) from solution most likely by both direct (enzymatic) and indirect (microbially generated reductant) mechanisms.

  15. Scattering States in AdS/CFT

    SciTech Connect

    Fitzpatrick, A.Liam; Kaplan, Jared; /SLAC

    2012-02-14

    We show that suitably regulated multi-trace primary states in large N CFTs behave like 'in' and 'out' scattering states in the flat-space limit of AdS. Their transition matrix elements approach the exact scattering amplitudes for the bulk theory, providing a natural CFT definition of the flat space S-Matrix. We study corrections resulting from the AdS curvature and particle propagation far from the center of AdS, and show that AdS simply provides an IR regulator that disappears in the flat space limit.

  16. ADS's Dexter Data Extraction Applet

    NASA Astrophysics Data System (ADS)

    Demleitner, M.; Accomazzi, A.; Eichhorn, G.; Grant, C. S.; Kurtz, M. J.; Murray, S. S.

    The NASA Astrophysics Data System (ADS) now holds 1.3 million scanned pages, containing numerous plots and figures for which the original data sets are lost or inaccessible. The availability of scans of the figures can significantly ease the regeneration of the data sets. For this purpose, the ADS has developed Dexter, a Java applet that supports the user in this process. Dexter's basic functionality is to let the user manually digitize a plot by marking points and defining the coordinate transformation from the logical to the physical coordinate system. Advanced features include automatic identification of axes, tracing lines and finding points matching a template. This contribution both describes the operation of Dexter from a user's point of view and discusses some of the architectural issues we faced during implementation.

  17. Consequences of dietary methyl donor supplements: Is more always better?

    PubMed

    Shorter, Kimberly R; Felder, Michael R; Vrana, Paul B

    2015-07-01

    Epigenetic mechanisms are now recognized to play roles in disease etiology. Several diseases increasing in frequency are associated with altered DNA methylation. DNA methylation is accomplished through metabolism of methyl donors such as folate, vitamin B12, methionine, betaine (trimethylglycine), and choline. Increased intake of these compounds correlates with decreased neural tube defects, although this mechanism is not well understood. Consumption of these methyl donor pathway components has increased in recent years due to fortification of grains and high supplemental levels of these compounds (e.g. vitamins, energy drinks). Additionally, people with mutations in one of the enzymes that assists in the methyl donor pathway (5-MTHFR) are directed to consume higher amounts of methyl donors to compensate. Recent evidence suggests that high levels of methyl donor intake may also have detrimental effects. Individualized medicine may be necessary to determine the appropriate amounts of methyl donors to be consumed, particularly in women of child bearing age. PMID:25841986

  18. Spectroscopic identification of ethanol-water conformers by large-amplitude hydrogen bond librational modes.

    PubMed

    Andersen, J; Heimdal, J; Wugt Larsen, R

    2015-12-14

    The far-infrared absorption spectra have been recorded for hydrogen-bonded complexes of water with ethanol embedded in cryogenic neon matrices at 2.8 K. The partial isotopic H/D-substitution of the ethanol subunit enabled by a dual inlet deposition procedure enables the observation and unambiguous assignment of the intermolecular high-frequency out-of-plane and the low-frequency in-plane donor OH librational modes for two different conformations of the mixed binary ethanol/water complex. The resolved donor OH librational bands confirm directly previous experimental evidence that ethanol acts as the O⋯HO hydrogen bond acceptor in the two most stable conformations. In the most stable conformation, the water subunit forces the ethanol molecule into its less stable gauche configuration upon dimerization owing to a cooperative secondary weak O⋯HC hydrogen bond interaction evidenced by a significantly blue-shift of the low-frequency in-plane donor OH librational band origin. The strong correlation between the low-frequency in-plane donor OH librational motion and the secondary intermolecular O⋯HC hydrogen bond is demonstrated by electronic structure calculations. The experimental findings are further supported by CCSD(T)-F12/aug-cc-pVQZ calculations of the conformational energy differences together with second-order vibrational perturbation theory calculations of the large-amplitude donor OH librational band origins. PMID:26671383

  19. A molecular electrostatic potential analysis of hydrogen, halogen, and dihydrogen bonds.

    PubMed

    Mohan, Neetha; Suresh, Cherumuttathu H

    2014-03-01

    Hydrogen, halogen, and dihydrogen bonds in weak, medium and strong regimes (<1 to ∼ 60 kcal/mol) have been investigated for several intermolecular donor-acceptor (D-A) complexes at ab initio MP4//MP2 method coupled with atoms-in-molecules and molecular electrostatic potential (MESP) approaches. Electron density ρ at bond critical point correlates well with interaction energy (Enb) for each homogeneous sample of complexes, but its applicability to the entire set of complexes is not satisfactory. Analysis of MESP minimum (V(min)) and MESP at the nuclei (Vn) shows that in all D-A complexes, MESP of A becomes more negative and that of D becomes less negative suggesting donation of electrons from D to A leading to electron donor-acceptor (eDA) interaction between A and D. MESP based parameter ΔΔVn measures donor-acceptor strength of the eDA interactions as it shows a good linear correlation with Enb for all D-A complexes (R(2) = 0.976) except the strongly bound bridged structures. The bridged structures are classified as donor-acceptor-donor complexes. MESP provides a clear evidence for hydrogen, halogen, and dihydrogen bond formation and defines them as eDA interactions in which hydrogen acts as electron acceptor in hydrogen and dihydrogen bonds while halogen acts as electron acceptor in halogen bonds. PMID:24506527

  20. Spectroscopic identification of ethanol-water conformers by large-amplitude hydrogen bond librational modes

    SciTech Connect

    Andersen, J.; Wugt Larsen, R.; Heimdal, J.

    2015-12-14

    The far-infrared absorption spectra have been recorded for hydrogen-bonded complexes of water with ethanol embedded in cryogenic neon matrices at 2.8 K. The partial isotopic H/D-substitution of the ethanol subunit enabled by a dual inlet deposition procedure enables the observation and unambiguous assignment of the intermolecular high-frequency out-of-plane and the low-frequency in-plane donor OH librational modes for two different conformations of the mixed binary ethanol/water complex. The resolved donor OH librational bands confirm directly previous experimental evidence that ethanol acts as the O⋯HO hydrogen bond acceptor in the two most stable conformations. In the most stable conformation, the water subunit forces the ethanol molecule into its less stable gauche configuration upon dimerization owing to a cooperative secondary weak O⋯HC hydrogen bond interaction evidenced by a significantly blue-shift of the low-frequency in-plane donor OH librational band origin. The strong correlation between the low-frequency in-plane donor OH librational motion and the secondary intermolecular O⋯HC hydrogen bond is demonstrated by electronic structure calculations. The experimental findings are further supported by CCSD(T)-F12/aug-cc-pVQZ calculations of the conformational energy differences together with second-order vibrational perturbation theory calculations of the large-amplitude donor OH librational band origins.