154,318 research outputs found
A possible mechanism of superconductivity in high-T-c cuprates
No full textThis paper derives a generic T-c formula by using the long-range phase coherence condition in quantum phase fluctuation of the order parameter. Taking the two-local-spin-mediated interaction (TLSMI) proposed by Liu and Chen [Phys. Rev. B 58 (1998) 8812] as a Cooper pair potential, and the T-c formula, this paper explains five basic experimental facts in high-T-c cuprates. The aim of this paper is to show that TLSMI is a possible pairing mechanism of superconductivity in high-T-c cuprates. (C) 2000 Elsevier Science B.V. All rights reserved.Physics, AppliedSCI(E)EI0ARTICLE4276-28434
Determination of the photolytic decomposition pathways of benzylchlorodiazirine by C60 probe technique
No full textBy employing C-60 as a chemical probe, the photolysis of benzylchlorodiazirine has been proposed to form carbene and the rearranged products via the excited state. (c) 2006 Elsevier Ltd. All rights reserved.PT: J; CR: AKASAKA T, 1999, ORG LETT, V1, P1509 AKASAKA T, 2000, J AM CHEM SOC, V122, P7134 FREY HM, 1965, J CHEM SOC, P1700 GRAHAM WH, 1965, J AM CHEM SOC, V87, P4396 HIRSCH A, 1993, CHEM BER, V126, P1061 ISHITSUKA MO, 2004, TETRAHEDRON LETT, V45, P6321 KORSHUNOVA GA, 2000, MOL BIOL+, V34, P823 LIU MTH, 1985, J CHEM SOC CHEM COMM, P982 LIU MTH, 1987, CHEM DIAZIRINES, V1 LIU MTH, 1987, CHEM DIAZIRINES, V2 LIU MTH, 1990, J AM CHEM SOC, V112, P3915 LIU MTH, 1992, J AM CHEM SOC, V114, P3604 LIU MTH, 2003, J ORG CHEM, V68, P7471 MODARELLI DA, 1992, J AM CHEM SOC, V114, P7034 NIGAM M, 1998, J AM CHEM SOC, V120, P8055 RICHARDS FM, 2000, PROTEIN SCI, V9, P2506 TOMIOKA H, 1984, J AM CHEM SOC, V106, P454 WAKAHARA T, 2002, J AM CHEM SOC, V124, P9465; NR: 18; TC: 0; J9: TETRAHEDRON LETT; PG: 3; GA: 130SPSource type: Electronic(1
Insertion of phenylchlorocarbenes in the C-H bonds of alkanes: measurement of the rate constants by laser flash photolysis
No full textPhenylchlorocarbenes, produced by photolysis of the parent diazirines, have a very limited lifetime in alkane solvents. The rate of disappearance of p-methyl- and p-chlorophenylchlorocarbenes has been measured in iso-octane, cyclohexane and n-hexane as well as in benzene for comparison. The rate constants of several processes (dimerization, addition to the diazirine, reaction with the solvent, etc. ) contributing to the disappearance of the phenylchlorocarbenes have been determined. The rate of reaction with the solvent, which is much lower in benzene than in alkanes and depends strongly on the nature of the alkane, is assumed to be an insertion of the carbene in the C-H bonds of the solvent. Consequences of this reaction on the chemistry of carbenes produced by continuous irradiation (or thermolysis) of diazirines in alkanes are briefly discussed.PT: J; CR: BENSASSON R, 1971, T FARADAY SOC, V67, P1904 BONNEAU R, 1986, NOUV J CHIM, V10, P425 BONNEAU R, 1991, PURE APPL CHEM, V63, P289 DOYLE MP, 1988, TETRAHEDRON LETT, V29, P5863 GOULD IR, 1985, TETRAHEDRON, V41, P1587 GRAHAM WH, 1965, J AM CHEM SOC, V87, P4396 LIU MTH, 1987, CHEM DIAZIRINES LIU MTH, 1990, J CHEM SOC CHEM COMM, P1482 LIU MTH, 1992, J AM CHEM SOC, V114, P3604 LIU MTH, 1992, J ORG CHEM, V57, P2483 LIU MTH, 1992, J PHOTOCH PHOTOBIO A, V63, P115 LUTZ H, 1973, J PHYS CHEM-US, V77, P1758 MORGAN S, 1991, J AM CHEM SOC, V113, P2782 MOSS RA, 1990, J AM CHEM SOC, V112, P5642 MOSS RA, 1990, KINETICS SPECTROSCOP; NR: 15; TC: 11; J9: J PHOTOCHEM PHOTOBIOL A-CHEM; PG: 10; GA: JQ196Source type: Electronic(1
A nonspectroscopic method to determine the photolytic decomposition pathways of 3-chloro-3-alkyldiazirine: Carbene, diazo and rearrangement in excited state
No full textC-60 acts as a mechanistic probe for the formation of carbene, diazo compound, and for the rearranged product via the excited state in the photolysis of 3-chloro-3-isopropyldiazirine and 3-chloro-3-chloromethyldiazirine. The carbene adds to C-60 to form methanofullerene, whereas the diazo compound adds to C-60 to form fulleroid. The olefin product arises as a result of the rearrangement in the excited state.PT: J; CR: AKASAKA T, 1999, J ORG CHEM, V64, P566 AKASAKA T, 1999, ORG LETT, V1, P1509 AKASAKA T, 2000, J AM CHEM SOC, V122, P7134 ARENAS JF, 2002, J AM CHEM SOC, V124, P1728 BECKE AD, 1988, PHYS REV A, V38, P3098 BECKE AD, 1993, J CHEM PHYS, V98, P5648 BONNEAU R, 1996, J AM CHEM SOC, V118, P3829 BONNEAU R, 1996, J AM CHEM SOC, V118, P7229 BRINKER U, 1994, ADV CARBENE CHEM, V1 BRINKER U, 1998, ADV CARBENE CHEM, V2 FRISCH MJ, 1998, GAUSSIAN 98 GRAHAM WH, 1965, J AM CHEM SOC, V87, P4396 HIRSCH A, 1993, CHEM BER, V126, P1061 JACKSON JE, 1988, J AM CHEM SOC, V110, P595 LAVILLA JA, 1989, J AM CHEM SOC, V111, P6877 LAVILLA JA, 1989, J AM CHEM SOC, V111, P712 LEE C, 1988, PHYS REV B, V37, P785 LIU MTH, 1987, CHEM DIAZIRINES, V1 LIU MTH, 1987, CHEM DIAZIRINES, V2 LIU MTH, 1996, J AM CHEM SOC, V118, P8098 MARTIN N, 1998, CHEM REV, V98, P2527 MODARELLI DA, 1992, J AM CHEM SOC, V114, P7034 PIETRO WJ, 1982, J AM CHEM SOC, V104, P5039 PLATZ MS, 1994, RES CHEM INTERMEDIAT, V20, P175 SCHICK G, 1998, TETRAHEDRON, V54, P4283 WHITE WR, 1992, J ORG CHEM, V57, P2841; NR: 26; TC: 8; J9: J AM CHEM SOC; PG: 4; GA: 582NTSource type: Electronic(1
Reaction of 3-chloro-3-methyldiazirines with hydrogen atoms
No full textPT: J; CR: BINGHAM RC, 1975, J AM CHEM SOC, V97, P1285 BRADLEY GF, 1977, J CHEM SOC P2, P1214 BRASLAVSKY S, 1977, CHEM REV, V77, P473 CHADWELL HM, 1933, J AM CHEM SOC, V55, P1363 CLARK DT, 1969, T FARADAY SOC, V62, P393 CLARK DT, 1969, T FARADAY SOC, V62, P399 CLARK DT, 1969, T FARADAY SOC, V62, P405 CLOUGH PN, 1970, CAN J CHEM, V48, P2919 DYKSTRA CE, 1978, J AM CHEM SOC, V100, P1378 FIGUERA JM, 1978, J CHEM SOC F1, P809 FREY HM, 1966, ADV PHOTOCHEM, V4, P225 FREY HM, 1977, J CHEM SOC F1, P2010 GILBERT JC, 1979, TETRAHEDRON LETT, P4619 GRAHAM WH, 1965, J AM CHEM SOC, V87, P4306 JAMIESON JWS, 1970, CAN J CHEM, V48, P3619 JENNINGS BM, 1976, J AM CHEM SOC, V98, P6416 JONES M, 1973, CARBENES, V1 JONES WE, CHEM BIOMED ENV INST JONES WE, 1973, CHEM REV, V73, P407 JONES WE, 1978, J CHEM SOC F2, V74, P831 LAU A, 1964, SPECTROCHIM ACTA, V20, P97 LIU MTH, UNPUBLISHED LIU MTH, 1973, CAN J CHEM, V51, P2393 LIU MTH, 1977, CAN J CHEM, V55, P3596 MAEDA Y, 1979, J AM CHEM SOC, V101, P837 MARTIN LR, 1979, INT J CHEM KINET, V11, P543 MEIER H, 1977, ANGEW CHEM INT EDIT, V16, P835 MOFFAT JB, 1978, CHEM DIAZONIUM DIA 1 MOSS RA, 1978, J CHEM SOC CHEM COMM, P775 SCHMITZ E, 1964, ANGEW CHEM INT EDIT, V3, P333 SCHMITZ E, 1971, 23RD INT C PUR ALL C, V2, P283 SCOTT PM, 1969, J PHYS CHEM-US, V73, P1513 SMITH NP, 1979, J CHEM SOC P2, P213 WITTER RA, 1973, J ORG CHEM, V38, P484; NR: 34; TC: 3; J9: J AMER CHEM SOC; PG: 2; GA: JN379Source type: Electronic(1
Tracking Virus-Specific CD4+ T Cells during and after Acute Hepatitis C Virus Infection
Full text linkBackground. CD4+ T cell help is critical in maintaining antiviral immune responses and such help has been shown to be sustained in acute resolving hepatitis C. In contrast, in evolving chronic hepatitis C CD4+ T cell helper responses appear to be absent or short-lived, using functional assays. Methodology/Prencipal Findings. Here we used a novel HLA-DR1 tetramer containing a highly targeted CD4+ T cell epitope from the hepatitis C virus non-structural protein 4 to track number and phenotype of hepatitis C virus specific CD4+ T cells in a cohort of seven HLA-DR1 positive patients with acute hepatitis C in comparison to patients with chronic or resolved hepatitis C. We observed peptide-specific T cells in all seven patients with acute hepatitis C regardless of outcome at frequencies up to 0.65% of CD4+ T cells. Among patients who transiently controlled virus replication we observed loss of function, and/or physical deletion of tetramer+ CD4+ T cells before viral recrudescence. In some patients with chronic hepatitis C very low numbers of tetramer+ cells were detectable in peripheral blood, compared to robust responses detected in spontaneous resolvers. Importantly we did not observe escape mutations in this key CD4+ T cell epitope in patients with evolving chronic hepatitis C. Conclusions/Significance. During acute hepatitis C a CD4+ T cell response against this epitope is readily induced in most, if not all, HLA-DR1 + patients. This antiviral T cell population becomes functionally impaired or is deleted early in the course of disease in those where viremia persists
Electrochemical behavior of diazirines
No full textPT: J; CR: ENGEL PS, 1980, CHEM REV, V80, P99 FRY AJ, 1973, J ORG CHEM, V38, P2620 KITAJEV JP, 1965, COLLECT CZECH CHEM C, V30, P4178 LIU MTH, 1981, J CHEM SOC P2, P53 LUND H, 1966, COLLECT CZECH CHEM C, V31, P4175 MALACHESKY PA, 1969, ANAL CHEM, V41, P1493 MOFFAT JB, 1978, CHEM DIAZONIUM DIA 1 NICHOLSON RS, 1964, ANAL CHEM, V36, P706 SCHWARZ WM, 1965, J PHYS CHEM-US, V69, P30; NR: 9; TC: 2; J9: J CHEM SOC CHEM COMMUN; PG: 2; GA: NJ399Source type: Electronic(1
Pyrolysis of trifluoroacetaldehyde, initiated by di-tertiary-butyl peroxide decomposition
No full textPT: J; CR: ARTHUR NL, 1965, AUST J CHEM, V18, P1561 AYSCOUGH PB, 1956, J CHEM PHYS, V24, P994 BATT L, 1977, INT J CHEM KINET, V9, P141 COME GM, 1968, REV I R PETROLE, V23, P1365 COX DL, 1966, J CHEM SOC B, P245 DODD RE, 1957, J CHEM SOC, P1465 FERGUSON JM, 1965, J CHEM SOC, P4416 GRAY P, 1971, CHEM REV, V71, P247 HIATT R, 1972, INT J CHEM KINET, V4, P479 HIATT R, 1978, INT J CHEM KINET, V10, P185 HOOPER DG, 1975, J CHEM EDUC, V52, P131 LIU MH, 1973, CAN J CHEM, V51, P2292 LIU MTH, 1968, CAN J CHEM, V46, P479 LIU MTH, 1977, INT J CHEM KINET, V9, P589 MORRIS ER, 1967, T FARADAY SOC, V63, P2470 MORRIS ER, 1968, T FARADAY SOC, V64, P3027 PEARCE C, 1971, J CHEM SOC CHEM COMM, P1464 SHAW DH, 1968, CAN J CHEM, V46, P2721 SHEPP A, 1956, J CHEM PHYS, V24, P939 WIJNEN MHJ, 1960, J AM CHEM SOC, V82, P1847 YEEQUEE MJ, 1968, J PHYSICAL CHEMISTRY, V72, P2824 YEEQUEE MJ, 1968, T FARADAY SOC, V64, P1296; NR: 22; TC: 10; J9: CAN J CHEM; PG: 10; GA: HN360Source type: Electronic(1
A verification of the photolytic decomposition pathways of 3-tert-butyl-3-chlorodiazirine based on the application of the C-60 probe technique
No full textC-60 acts as a mechanistic probe for the formation of carbene and for the rearranged product via the excited state in the photolysis of 3-t-butyl-3-chlorodiazirine. (C) 2004 Published by Elsevier Ltd.PT: J; CR: AKASAKA T, 2000, J AM CHEM SOC, V122, P7134 BONNEAU R, 2000, J PHYS CHEM A, V104, P4115 DIEDERICH F, 1994, CHEM SOC REV, V1, P243 GRAHAM WH, 1965, J AM CHEM SOC, V87, P4396 HIRSH A, 1999, FULLERENES RELATED S KORSHUNOVA GA, 2000, MOL BIOL+, V34, P823 LIU MTH, 1996, J AM CHEM SOC, V118, P8098 MODARELLI DA, 1992, J AM CHEM SOC, V114, P7034 MODARELLI DA, 1993, J AM CHEM SOC, V115, P470 MOSS RA, 1990, J AM CHEM SOC, V112, P5642 MOSS RA, 1993, J CHEM SOC CHEM COMM, P1597 RICHARDS FM, 2000, PROTEIN SCI, V9, P2506 WAKAHARA T, 2002, J AM CHEM SOC, V124, P9465 WHITE WR, 1992, J ORG CHEM, V57, P2841; NR: 14; TC: 2; J9: TETRAHEDRON LETT; PG: 2; GA: 843UMSource type: Electronic(1
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