361 research outputs found
Outer-sphere electron transfer reactions of aqua(5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane-1-aceta to) nickel(II) and (III).
No full textThe outer-sphere oxidation of the nickel(II) complex of the deprotonated pendant-arm macrocycle, 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane-1-acetate, [NiL1(OH2)](+) by bis-(1,4,7-triazacyclononane)nickel(III), [Ni(tacn)(2)](3+) has been studied in aqueous perchlorate media. The reaction displays reversible second-order behaviour and the kinetic study reveals the forward and reverse rate constants for the reaction: [Ni(tacn)(2)](3+) + [NiL1(OH2)](+) reversible arrow [Ni(tacn)(2)](2+) + [NiL1(OH2)](2+) The kinetics show the forward reaction to be acid dependent, a feature that is attributed to protonation of the acetato group of the nickel(II) complex. Using Marcus theory, the self-exchange rate for the [NiL1(OH2)](+/2+) couple has been calculated. The nickel(II/III) electron transfer is a reversible one electron process with Edegrees = 1.04 V (vs. S.H.E.). The formation of the authentic nickel(III) product has been confirmed by esr spectroscopy. The kinetics of reduction of the [NiL1(OH2)](2+) species by Fe2+(aq) exhibits a second-order rate law, the reaction being independent of acid. Using the calculated self-exchange rate for the nickel complex, its reaction with Fe2+(aq) has been examined in terms of an inner- versus outer-sphere mechanism.PT: J; CR: AIME S, 1995, J CHEM SOC DA, P2259 AIME S, 1999, COORDIN CHEM REV, V186, P321 BRODOVITCH JC, 1981, CAN J CHEM, V59, P1610 BRODOVITCH JC, 1981, INORG CHEM, V20, P1667 BRUNSCHWIG BS, 1982, FARADAY DISCUSS, V74, P113 CHOU M, 1977, J AM CHEM SOC, V99, P5615 COX JPL, 1989, J CHEM SOC CHEM COMM, P797 DUCOMMUN Y, 1980, INORG CHEM, V19, P3696 FAIRBANK MG, 1985, CAN J CHEM, V63, P2983 HAINES RI, 1981, COORDIN CHEM REV, V39, P77 HAINES RI, 2001, CAN J CHEM, V79, P54 HAINES RI, 2001, J INORG BIOCHEM, V85, P1 HUSH NS, 1961, T FARADAY SOC, V57, P557 JOLLEY WH, 1990, INORG CHEM, V29, P1948 JORDAN RB, 1991, REACTION MECH INORGA, P203 JORDAN RB, 1998, REACTION MECH INORGA, CH3 KIMURA E, 1985, J CHEM SOC CHEM COMM, P385 KING EL, 1982, INT J CHEM KINET, V14, P1285 LAPPIN AG, 1982, J CHEM SOC DA, P1861 LEMMA K, 2000, J CHEM SOC DALTON, P1167 LOVECCHIO FV, 1974, J AM CHEM SOC, V96, P3109 MACARTNEY DH, 1983, INORG CHEM, V22, P3530 MACARTNEY DH, 1985, INORG CHEM, V24, P307 MARCUS RA, 1964, ANNU REV PHYS CHEM, V15, P155 MARCUS RA, 1985, BIOCHIM BIOPHYS ACTA, V811, P265 MCAULEY A, 1982, J CHEM SOC CHEM COMM, P274 MCAULEY A, 1984, INORG CHEM, V23, P1938 MCAULEY A, 1984, INORG CHEM, V23, P2594 MORPHY JR, 1989, J CHEM SOC CHEM COMM, P792 PELIZZETTI E, 1979, INORG CHEM, V18, P583 SEARLE GH, 1984, AUST J CHEM, V37, P959 SHERRY AD, 1989, INORG CHEM, V28, P620 SPERANZINI RA, 1989, MATER PERFORMANCE, V28, P67 SUTIN N, 1982, ACCOUNTS CHEM RES, V15, P275 TACHIKAWA E, 1984, NUCL TECHNOL, V65, P138 WEAVER MJ, 1980, INORG CHEM, V19, P1936 XU JD, 1986, INORG CHIM ACTA, V111, P61; NR: 37; TC: 1; J9: CAN J CHEM; PG: 7; GA: 652JVSource type: Electronic(1
Initial state and transition-state solvation effects in the cobaltotungstate oxidation of iodide in binary aqueous solvent mixtures
No full textPT: J; CR: AMJAD Z, 1977, CAN J CHEM, V55, P3581 BAKER LCW, 1956, J AM CHEM SOC, V78, P4503 BECK MT, 1968, COORDIN CHEM REV, V3, P91 BLANDAMER MJ, UNPUB CAN J CHEM BLANDAMER MJ, 1978, J CHEM SOC CHEM COMM, P963 BLANDAMER MJ, 1979, PURE APPL CHEM, V51, P2087 BLANDAMER MJ, 1980, COORDIN CHEM REV, V31, P93 BLANDAMER MJ, 1980, J CHEM SOC DA, P1 BLANDAMER MJ, 1980, J CHEM SOC DA, P2442 BRODOVITCH JC, UNPUB BURGESS J, 1968, J CHEM SOC A, P2571 BURGESS J, 1970, J CHEM SOC A, P2111 BURGESS J, 1970, J CHEM SOC A, P2351 BURGESS J, 1972, INORGANIC REACTION M, V2, P127 BURGESS J, 1973, J CHEM SOC A, P825 BURGESS J, 1974, INORGANIC REACTION M, V3, P142 BURGESS J, 1977, INORGANIC REACTION M, V5, P158 BURGESS J, 1979, INORGANIC REACTION M, V6, P168 COX BG, 1974, ANN REP CHEM SOC A, V71, P249 COX BG, 1979, J CHEM SOC F1, V75, P1780 COX BG, 1979, J CHEM SOC FARAD T 1, V75, P86 DELIGNY CL, 1965, RECL TRAV CHIM PAY B, V84, P81 ELLIS KJ, 1973, J CHEM SOC DA, P1533 GRUNWALD E, 1948, J AM CHEM SOC, V70, P846 KANEMAQUIRE LAP, 1975, J CHEM SOC DA, P1890 KEPERT DL, 1978, J CHEM SOC DA, P137 MARCUS RA, 1968, J PHYS CHEM-US, V72, P891 PELIZZETTI E, 1976, INORG CHEM, V15, P2898 SUBHANI MS, 1978, REV ROUMAINE CHIM, V23, P719 UDOVENKO VV, 1977, RUSS J INORG CHEM, V22, P168 WELLS CF, 1973, J CHEM SOC FARAD T 1, V69, P984 WELLS PR, 1968, LINEAR FREE ENERGY R, CH4; NR: 32; TC: 14; J9: TRANSIT METAL CHEM; PG: 4; GA: NG073Source type: Electronic(1
International political economy (IPE) and the demand for political philosophy in an era of globalisation
No full textRecent years have seen international political economy (IPE) become an increasingly bifurcated field of inquiry. On the one hand deductive, rational choice driven analysis has taken IPE increasingly in the direction of economic analysis toute courte. This has especially been the case in the United States. On the other hand, driven more by the largely inductive tradition in the non-economic social sciences, IPE, especially in a European and 'southern' context has become more, indeed as some would argue excessively, 'reflexive' in direction. One approach asserts its social scientific status while the other asserts its normative imperatives. This bifurcation is undesirable and, this paper argues, unsustainable in the contemporary era. The need to understand and explain globalisation should, in both theory and practice, make this bifurcation redundant. Fortunately there are elements of an evolving IPE that is increasingly historically and empirically grounded, analytically sophisticated and in search of tighter, less indulgent, more policy relevant, normative purchase on key issues of IPE such as justice, equality and development. It is doing this by paying close attention to work on these issues by normative political philosophers. Similarly, political philosophers are recognising the need to come to terms with the research agendas of IPE. This coming together is not an easy process. Indeed it is in its formative stages. But it is an important scholarly project, and one which should cast larger policy shadows over the global order, which is likely to gather momentum over the next few years
Kinetics and mechanisms of the oxidation of ascorbic-acid and benzene diols by nickel(iii)tetraazamacrocycles in aqueous perchloric-acid
No full textPT: J; CR: AMJAD Z, 1977, CAN J CHEM, V55, P3581 BALL EG, 1937, J BIOL CHEM, V118, P219 BENCINI A, 1981, INORG CHEM, V20, P2544 BOSNICH B, 1965, INORG CHEM, V4, P1102 BOSNICH B, 1965, INORG CHEM, V4, P1109 BRODOVITCH JC, 1982, INORG CHEM, V21, P3442 BROWN GM, 1979, J AM CHEM SOC, V101, P883 CREUTZ C, 1981, INORG CHEM, V20, P4449 CURTIS NF, 1966, J CHEM SOC A, P1015 ELLIS KJ, 1973, J CHEM SOC DA, P1533 GAGNE RR, 1981, INORG CHEM, V20, P420 GUPTA RK, 1972, J MAGN RESON, V7, P66 HAINES RI, 1980, INORG CHEM, V19, P719 JAACOBI M, 1979, INORG CHEM, V18, P429 KIMURA M, 1982, J CHEM SOC DA, P423 KUSTIN K, 1972, INORG CHEM, V11, P1952 LAURENCE GS, 1972, J CHEM SOC DA, P1667 LOVECCHIO FV, 1974, J AM CHEM SOC, V96, P3109 MACARTNEY DH, 1981, CAN J CHEM, V59, P132 MARCUS RA, 1968, J PHYS CHEM-US, V72, P891 MARTELL AE, 1977, CRITICAL STABILITY C, V3, P264 MCAULEY A, 1982, J CHEM SOC CHEM COMM, P274 MEHROTRA US, 1969, J PHYS CHEM-US, V73, P1996 MENTASTI E, 1977, INT J CHEM KINET, V9, P215 OSWALD T, UNPUB PELIZZETTI E, 1976, INORG CHEM, V15, P2898 PELIZZETTI E, 1977, J CHEM SOC DA, P132 PELIZZETTI E, 1978, INORG CHEM, V17, P1181 PELIZZETTI E, 1978, INORG CHEM, V17, P1688 PELIZZETTI E, 1978, J CHEM SOC DA, P61 PELIZZETTI E, 1978, J CHEM SOC P2, P620 PHILLIPS J, 1980, INORG CHEM, V19, P76 RICHMAN RA, 1977, INORG CHEM, V16, P1570 RILLEMA DP, 1972, J AM CHEM SOC, V94, P394 RILLEMA DP, 1972, J AM CHEM SOC, V94, P8711 STEENKEN S, 1979, J PHYS CHEM-US, V83, P1134 TAQUIKHAN MM, 1968, J AM CHEM SOC, V90, P3386 WELLS CF, 1966, T FARADAY SOC, V62, P2815 WOODS M, 1978, J INORG NUCL CHEM, V40, P1907 ZEIGERSON E, 1979, J CHEM SOC CHEM COMM, P241 ZEIGERSON E, 1980, J CHEM SOC DA, P1243 ZEIGERSON E, 1981, INORG CHEM, V20, P3988; NR: 42; TC: 20; J9: CAN J CHEM; PG: 6; GA: QX881Source type: Electronic(1
Theoretical and experimental considerations of the critical current density of DI-BiSCCO superconducting tapes as a function of magnetic field, field orientation, temperature and strain
No full textThe critical current density (Jc) of DI-BiSCCO superconducting tapes was measured as a function of magnetic field (B), field orientation (θ), temperature (T) and strain (e) in a 15 T split-pair horizontal superconducting magnet using probes designed and built in-house. Strain was applied to samples using a modified bending beam apparatus with a copper beryllium springboard-shaped sample holder, which is capable of applying uniaxial strains of -1.4% < e < 1.0%. The temperature of the sample was controlled with the use of an inverted insulating cup with a temperature stability of +/-80 mK to +/-200 mK. The vapour-cooled brass critical-current leads (incorporating high-temperature superconducting tapes) were optimised to minimise helium consumption. Optimisation includes consideration of the maximum safe temperature of the current leads and the effects of duty cycle and static helium boil-off. The optimised helium consumption of the leads is a factor of two lower than standard current leads optimised for magnets. Jc(B,T,θ,e) data of the DI-BiSCCO tapes were characterised based on the superconducting-normal-superconducting Josephson junction model where Jc is determined by flux flow along the grain boundaries (or the normal junctions). It was found that grain boundaries in the DI-BiSCCO tapes are thick (several tens of nanometre) and exhibit semiconducting behaviour. The degree of misalignment has been included into the anisotropy analysis of Jc and the correlation between the effective anisotropy and texturing of the sample obtained. Analysis of three different samples (Nb3Sn, YBCO and BiSCCO) is presented where the average local properties of the grain boundaries were extracted from magnetisation and the transport Jc data
Delta(3)-1,3,4-oxadiazolines: Photochemical precursors to diazoalkanes and sec-alkanediazonium ions in acidic solution
No full textPT: J; CR: ADAM W, 1990, TETRAHEDRON LETT, V31, P863 ALBERY WJ, 1972, J CHEM SOC P2, P2206 BELL RP, 1973, PROTON CHEM BROSCH D, 1991, J ORG CHEM, V56, P907 BROSCH D, 1993, J ORG CHEM, V58, P1118 BROWN HC, 1957, TETRAHEDRON, V1, P214 BROWN HC, 1957, TETRAHEDRON, V1, P221 BUNSE M, 1993, CHEM BER, V126, P1499 CHIANG Y, 1995, J AM CHEM SOC, V117, P9165 CHIANG Y, 1996, J AM CHEM SOC, V118, P4366 COLLINS CJ, 1971, ACCOUNTS CHEM RES, V4, P315 FINNEMAN JI, 1993, J AM CHEM SOC, V115, P3016 FINNEMAN JI, 1994, J ORG CHEM, V59, P6251 FINNEMAN JI, 1995, J AM CHEM SOC, V117, P4228 GOLD B, 1984, J AM CHEM SOC, V106, P2072 HO J, 1994, J AM CHEM SOC, V116, P6611 HOVINEN J, 1992, J AM CHEM SOC, V114, P10321 HUISGEN R, 1955, ANGEW CEHM, V67, P273 IZUTSU K, 1990, IUPAC CHEM DATA SERI, V35 KAZANIS S, 1991, J PHYS CHEM-US, V95, P4430 KIRMSE W, 1976, ANGEW CHEM INT EDIT, V15, P251 KRESGE AJ, 1973, CHEM SOC REV, V2, P475 KRESGE AJ, 1975, PROTON TRANSFER REAC, CH7 KRESGE AJ, 1986, J ORG CHEM, V51, P819 KRESGE AJ, 1986, J ORG CHEM, V51, P822 LAALI K, 1986, REV CHEM INTERMED, V6, P237 LARSON JW, 1987, J AM CHEM SOC, V109, P6230 LAWSON T, 1988, CARCINOGENESIS, V9, P1007 LEUNG KH, 1984, CHEM-BIOL INTERACT, V48, P169 LIBERATO DJ, 1989, CHEM RES TOXICOL, V2, P307 LIJINSKY W, 1992, CHEM BIOL N NITROSO MAJCHRZAK MW, 1989, J ORG CHEM, V54, P1842 MARCUS RA, 1968, J PHYS CHEM-US, V72, P891 MCGARRITY JF, 1980, J AM CHEM SOC, V102, P7303 MOSS RA, 1974, ACCOUNTS CHEM RES, V7, P421 MURRAY CJ, 1990, J AM CHEM SOC, V112, P1880 OFERRALL RAM, 1967, ADV PHYS ORG CHEM, V5, P331 WAGNER BD, UNPUB WASHABAUGH MW, 1988, BIOCHEMISTRY-US, V27, P5044 WASHABAUGH MW, 1989, J AM CHEM SOC, V111, P674 WHITTAKER D, 1978, CHEM DIAZONIUM DIAZO, P617 YOUNG JC, 1975, CAN J CHEM, V53, P2530 ZOLLINGER H, 1995, DIAZO CHEM, V1; NR: 43; TC: 11; J9: J AMER CHEM SOC; PG: 2; GA: WJ097Source type: Electronic(1
Hiperplasia congênita de supra-renal por deficiência da 21-hidroxilase: altura final de 17 pacientes com a forma clássica.
No full textTrabalho de Conclusão de Curso - Universidade Federal de Santa Catarina. Curso de Medicina. Departamento de Pediatria
A53T-alpha-synuclein-overexpression in the mouse nigrostriatal pathway leads to early increase of 14-3-3 epsilon and late increase of GFAP
No full textParkinson’s disease (PD) is a neurodegenerative disorder frequent at old age characterized by atrophy of the nigrostriatal projection. Overexpression and A53T-mutation of the presynaptic, vesicle-associated chaperone alpha-synuclein are known to cause early-onset autosomal dominant PD. We previously generated mice with transgenic overexpression of human A53T-alpha-synuclein (A53T-SNCA) in dopaminergic substantia nigra neurons as a model of early PD. To elucidate the early and late effects of A53T-alpha-synuclein on the proteome of dopaminergic nerve terminals in the striatum, we now investigated expression profiles of young and old mice using two-dimensional fluorescence difference in gel electrophoresis (2D-DIGE) and mass spectrometry. In total, 15 proteins were upregulated and 2 downregulated. Mice before the onset of motor anomalies showed an upregulation of the spot containing 14-3-3 proteins, in particular the epsilon isoform, as well as altered levels of chaperones, vesicle trafficking and bioenergetics proteins. In old mice, the persistent upregulation of 14-3-3 proteins was aggravated by an increase of glial fibrillary acidic protein (GFAP) suggesting astrogliosis due to initial neurodegeneration. Independent immunoblots corroborated GFAP upregulation and 14-3-3 upregulation for the epsilon isoform, and also detected significant eta and gamma changes. Only for 14-3-3 epsilon a corresponding mRNA increase was observed in midbrain, suggesting it is transcribed in dopaminergic perikarya and accumulates as protein in presynapses, together with A53T-SNCA. 14-3-3 proteins associate with alpha-synuclein in vitro and in pathognomonic Lewy bodies of PD brains. They act as chaperones in signaling, dopamine synthesis and stress response. Thus, their early dysregulation probably reflects a response to alpha-synuclein toxicity.
Electronic supplementary material: The online version of this article (doi:10.1007/s00702-011-0717-3) contains supplementary material, which is available to authorized users
Systemic medications and other risk factors of open-angle glaucoma
No full textHet onderzoek in dit proefschrift is ontworpen om de werking van sommige systemische geneesmiddelen te ontcijferen en een aantal andere risicofactoren van open-kamerhoek glaucoom (OKG) te onderzoeken.
De studies gepresenteerd in de eerste drie hoofdstukken zijn gebaseerd op het Erasmus Rotterdam Gezondheids Onderzoek (ERGO/ Rotterdamstudie), een prospectief populatie-gebaseerde cohort studie van ouderdomgerelateerde aandoeningen. Onze studie populatie bestaat uit 3939 van de oorspronkelijke 7983 deelnemers van 55 jaar en ouder uit het Rotterdamse onderzoek. In hoofdstuk een hebben we onderzocht of het gebruik van cholesterol- verlagende geneesmiddelen geassocieerd is met een verlaagd risico op (OKG). We hebben de relatie tussen het gebruik van corticosteroïden en incident OKG onderzocht in hoofdstuk twee. In hoofdstuk 3 is onderzocht of antitrombotica het risico van OKG kan verminderen.
Het centrale thema van de hoofdstukken 4, 5 en 6 is het gebruik van statistische methodologie, systematische review en meta-analyse om andere risicofactoren van OKG te verhelderen. Hoofdstuk 4 beschrijft de risico's die samenhangen met visuele veldprogressie in OKG door het vergelijken van verschillende statistische benaderingen in de Groningen Longitudinal Glaucoma Study (GLGS), een prospectieve cohort studie in een klinische setting. Hoofdstuk 5 presenteert in een systematische review en meta-analyse de relatie tussen bijziendheid en OKG. Hoofdstuk 6 biedt een overzicht van de huidige stand van kennis van het effect van systemische geneesmiddelen op OKG.
The research presented in this thesis was designed to decipher the effect of some systemic medications and some other risk factors of OAG. The studies presented in the first three chapters are based on the Rotterdam Study, a prospective population-based cohort study of age related disorders in the elderly. Our study population comprised of 3939 of the original 7983 participants aged 55 years and older from the Rotterdam study. In chapter 1 we studied whether the use of cholesterol-lowering drugs is associated with a reduced risk of OAG. In chapter 2 we explored the association between corticosteroid use and incident OAG. In chapter 3 we studied whether antithrombotics could reduce the risk of OAG.
The central theme of chapters 4, 5 and 6 is the use of statistical methodology, systematic review and meta-analysis to elucidate other risk factors of OAG. Chapter 4 describes the risk factors associated with visual field progression in OAG by comparing different statistical approaches in the Groningen Longitudinal Glaucoma Study (GLGS), a prospective cohort study in a clinical setting. Chapter 5 presents a systematic review and meta-analysis to examine the association between myopia and OAG. Chapter 6 reviews the current state of knowledge of the effect of systemic medications on OAG.
Controls on gut phosphatisation : the trilobites from the Weeks Formation Lagerstätte (Cambrian; Utah)
No full textDespite being internal organs, digestive structures are frequently preserved in Cambrian Lagerstätten. However, the reasons for their fossilisation and their biological implications remain to be thoroughly explored. This is particularly true with arthropods--typically the most diverse fossilised organisms in Cambrian ecosystems--where digestive structures represent an as-yet underexploited alternative to appendage morphology for inferences on their biology. Here we describe the phosphatised digestive structures of three trilobite species from the Cambrian Weeks Formation Lagerstätte (Utah). Their exquisite, three-dimensional preservation reveals unique details on trilobite internal anatomy, such as the position of the mouth and the absence of a differentiated crop. In addition, the presence of paired pygidial organs of an unknown function is reported for the first time. This exceptional material enables exploration of the relationships between gut phosphatisation and the biology of organisms. Indeed, soft-tissue preservation is unusual in these fossils as it is restricted to the digestive structures, which indicates that the gut played a central role in its own phosphatisation. We hypothesize that the gut provided a microenvironment where special conditions could develop and harboured a source of phosphorus. The fact that gut phosphatization has almost exclusively been observed in arthropods could be explained by their uncommon ability to store ions (including phosphorous) in their digestive tissues. However, in some specimens from the Weeks Formation, the phosphatisation extends to the entire digestive system, suggesting that trilobites might have had some biological particularities not observed in modern arthropods. We speculate that one of them might have been an increased capacity for ion storage in the gut tissues, related to the moulting of their heavily-mineralised carapace
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