1126
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Yu X, Duxbury PM, Jeffers G, Dubson MA. Coalescence and percolation in thin metal films. PHYSICAL REVIEW. B, CONDENSED MATTER 1991; 44:13163-13166. [PMID: 9999516 DOI: 10.1103/physrevb.44.13163] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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1127
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Yu X. [A clinical study of 100 cases of AIDS in Africa]. ZHONGHUA YI XUE ZA ZHI 1991; 71:674-5, 46. [PMID: 1667369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
In this article, 100 cases of AIDS observed in Africa by the Chinese Medical Team are reported. The general clinical data were analyzed and studied, and the changes in the oral cavity and on the skin (Kaposi's sarcoma) are described. The results showed that oral mycotic infection and Kaposi's sarcoma are the strong evidences of this immunity deficiency and may be regarded as the early stage clinical manifestations of AIDS in Africa.
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1128
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Yu X, Zhou W. [The investigation of intrahospital infection in cardiovascular surgery and its nursing strategy]. ZHONGHUA HU LI ZA ZHI = CHINESE JOURNAL OF NURSING 1991; 26:482-5. [PMID: 1782699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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1129
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Carroll S, Skarmeta JG, Yu X, Collins KD, Inesi G. Interdependence of ryanodine binding, oligomeric receptor interactions, and Ca2+ release regulation in junctional sarcoplasmic reticulum. Arch Biochem Biophys 1991; 290:239-47. [PMID: 1898095 DOI: 10.1016/0003-9861(91)90615-p] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
We have examined ryanodine binding to its receptor (RR) and compared its effect on Ca2+ release to the Ca2+ release triggered by Ca2+ plus ATP, using vesicular fragments of junctional terminal cisternae (JTC) obtained from skeletal muscle. Ryanodine binding is slow (taking hours or days to complete) and is highly temperature (Q10 = 4) and Ca2+ dependent. At equilibrium, the extent of binding increases as the concentration of ryanodine is raised above 10(-9) M, exhibiting negative cooperativity and reaching the stoichiometry of the 560,000-Da RR chains near 10(-5) M ryanodine. The specificity of the high affinity binding is demonstrated by competitive binding of ryanodine analogs. Kinetic studies using rapid filtration show that, in the absence of ryanodine, rapid (k = 15 s-1) release of Ca2+ follows a triggering exposure of loaded JTC vesicles to perfusion media containing Ca2+ plus ATP. Induction of this release has no lag period and displays minimal temperature dependence. In contrast, prolonged exposure of JTC vesicles to low (10(-7) M) ryanodine concentrations changes the JTC to a state permitting slow (k = 1 s-1) release of Ca2+ even in the absence of the Ca2+ plus ATP trigger. Higher (greater than microM) concentrations of ryanodine do not allow any Ca2+ release and prevent even the release normally triggered by Ca2+ plus ATP. Our data suggest that ryanodine binds to the open state of the tetrameric RR, inducing protein conformational changes and altered oligomeric interactions. Binding of the first molecule of ryanodine to one of the four binding sites on the receptor produces a partially closed and low conductance state of the Ca2+ release channel and reduces the ryanodine binding affinity of the remaining sites. Ryanodine occupancy of all four binding sites on the receptor completes closure of the Ca2+ channel and blocks the triggering action of Ca2+ plus ATP. The tetrameric association of the RR chains is demonstrated by crosslinking with bifunctional reagents, generating crosslinked tetramers that retain ryanodine binding and Ca2+ release functions.
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1130
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Jones-Woodward CE, Beise EJ, Belz JE, Carr RW, Filippone BW, Lorenzon W, McKeown RD, Mueller BA, O'Neill TG, Dodson G, Dow K, Farkhondeh M, Kowalski S, Lee K, Makins N, Milner R, Thompson A, Tieger D, Young A, Yu X, Zumbro JD. Determination of the neutron electric form factor in quasielastic scattering of polarized electrons from polarized 3He. PHYSICAL REVIEW. C, NUCLEAR PHYSICS 1991; 44:R571-R574. [PMID: 9967486 DOI: 10.1103/physrevc.44.r571] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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1131
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Ma X, Yu X, Zheng Z, Mao J. Analytical supercritical fluid extraction of Chinese herbal medicines. Chromatographia 1991. [DOI: 10.1007/bf02262464] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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1132
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Yu X, Egelman EH. Removal of the RecA C-terminus results in a conformational change in the RecA-DNA filament. J Struct Biol 1991; 106:243-54. [PMID: 1804279 DOI: 10.1016/1047-8477(91)90074-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The Escherichia coli RecA protein catalyzes homologous recombination of DNA molecules, and the active form of the protein is a helical polymer that it forms around DNA. Previous image analysis of electron micrographs has revealed the RecA protein to be organized into two domains or lobes within the RecA-DNA filament. We have now been able to show that a small modification of the RecA protein by proteolysis results in a significant shift in the internal mass in the RecA filament. We have cleaved approximately 18 residues from the C-terminus of the RecA protein, producing a roughly 36K MW RecA core protein that binds DNA and polymerizes normally. A three-dimensional reconstruction of this complex has been computed, and has been compared with a previous reconstruction of the intact protein. The main difference is consistent with a 15 A outward movement of the lobe that was at an inner radius in the wild-type protein. These observations yield additional evidence about the conformational flexibility of the RecA filament, and will aid in understanding the structural mechanics and dynamics of the RecA filament.
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1133
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Morabito MA, Yu X, Barnstable CJ. Characterization of developmentally regulated and retina-specific nuclear protein binding to a site in the upstream region of the rat opsin gene. J Biol Chem 1991; 266:9667-72. [PMID: 1827795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
DNase I protection and gel retardation assays have identified a sequence 5' to the transcription start site of the rat opsin gene that interacts with nuclear proteins from mammalian retinas but not from a variety of other neural and non-neural tissues. Following sodium dodecyl sulfate-polyacrylamide gel electrophoresis and transfer to nitrocellulose the protein(s) responsible for this binding were identified with an oligonucleotide probe and were found to migrate with an apparent molecular size of 40 kilodaltons. The binding complex eluted from fast protein liquid chromatography gel filtration as a peak centered at 100 kilodaltons, suggesting the presence of more than one subunit. Binding activity could be detected in postnatal day 1 retinal extracts and increased over the next 2 weeks of development, a time course coincident with opsin gene expression and maturation of rod photoreceptors. Synthetic oligonucleotides with altered sequences showed that the binding was dependent upon residues in a CTAAT motif and was facilitated by surrounding GGCCCC sequences. The specificity of the binding interaction was measured by inhibition of complex formation in a gel retardation assay. The unaltered sequence was over 2 orders of magnitude more effective at inhibiting complex formation than either an unrelated DNA sequence or a concensus sequence corresponding to a known CCAAT box binding protein NF1.
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1134
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Morabito M, Yu X, Barnstable C. Characterization of developmentally regulated and retina-specific nuclear protein binding to a site in the upstream region of the rat opsin gene. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)92872-3] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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1135
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Woodward CE, Beise EJ, Belz JE, Carr RW, Filippone BW, Lorenzon WB, McKeown RD, Mueller B, O'Neill TG, Dodson G, Dow K, Farkhondeh M, Kowalski S, Lee K, Makins N, Milner R, Thompson A, Tieger D, Young A, Yu X, Zumbro J. Measurement of inclusive quasielastic scattering of polarized electrons from polarized 3He. PHYSICAL REVIEW LETTERS 1990; 65:698-700. [PMID: 10042996 DOI: 10.1103/physrevlett.65.698] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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1136
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Jiang B, Liao X, Jia X, Ye X, Ding J, Yu X, Wu Y. [Studies and comparisons on chemical components of essential oils from Clematis hexapetala Pall. and Inula nervosa Wall]. ZHONGGUO ZHONG YAO ZA ZHI = ZHONGGUO ZHONGYAO ZAZHI = CHINA JOURNAL OF CHINESE MATERIA MEDICA 1990; 15:488-90, 512. [PMID: 2093324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Chemical components of the essential oils from clematis hexapetala and Inula nervosa were analyzed by using GC-MS-DS. The result shows that the major components of the essential oil from Inula nervosa are thymol and thymol isobutyrate, while the major components of the essential oil from Clematis hexapetala are palmitic acid and 3-hydroxy-4-methoxyl benzaldehyde.
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1137
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Yu X, Raisanen A, Haugstad G, Ceccone G, Troullier N, Franciosi A. Low-temperature photoemission measurements of valence-band discontinuities at buried heterojunctions. PHYSICAL REVIEW. B, CONDENSED MATTER 1990; 42:1872-1875. [PMID: 9995627 DOI: 10.1103/physrevb.42.1872] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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1138
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Shaviv R, Westrum EF, Brown RJC, Sayer M, Yu X, Weir RD. The heat capacity and derived thermophysical properties of the high TC superconductor YBa2Cu3O7−δ from 5.3 to 350 K. J Chem Phys 1990. [DOI: 10.1063/1.458266] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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1139
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Franciosi A, Raisanen A, Haugstad G, Ceccone G, Yu X. Probing island growth and coalescence at metal-semiconductor interfaces. PHYSICAL REVIEW. B, CONDENSED MATTER 1990; 41:7914-7917. [PMID: 9993102 DOI: 10.1103/physrevb.41.7914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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1140
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Yu X. [Genic localization of an epitope of HPV 16 E7 ORF]. ZHONGHUA YI XUE ZA ZHI 1990; 70:229. [PMID: 1697215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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1141
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Yu X. [Isolation and identification of penicillin-resistant Neisseria gonorrhoeae in Chongqing District]. ZHONGHUA YI XUE ZA ZHI 1990; 70:151-3. [PMID: 2163742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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1142
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Abstract
The Escherichia coli RecA protein catalyzes homologous genetic recombination by forming helical polymers around DNA molecules. These polymers have an ATPase activity, which is essential for the movement of strands between two DNA molecules. One obstacle to structural studies of the RecA filament has been that the ATPase results in a dynamical polymer containing a mixture of states with respect to the bound ATP and its hydrolytic products. We have formed filaments which are trapped in the ADP-Pi state by substituting AIF4- for the Pi, and have used these stable filaments to generate a three-dimensional reconstruction from electron micrographs. The resolution of the reconstruction is sufficient to resolve the 38-k RecA subunit into two nearly equal domains. This reconstruction provides the most detailed view yet of the RecA protein, and serves as a framework within which existing biochemical data on RecA can be understood.
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1143
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Reed I, Yu X. Adaptive multiple-band CFAR detection of an optical pattern with unknown spectral distribution. ACTA ACUST UNITED AC 1990. [DOI: 10.1109/29.60107] [Citation(s) in RCA: 1019] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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1144
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Abstract
The helical filament that the RecA protein of Escherichia coli forms around DNA is the active apparatus in protein-catalyzed homologous genetic recombination. The actual position of DNA within this complex has been unknown. Image analysis has been performed on electron micrographs of filaments of RecA on double-stranded DNA and on single-stranded DNA to visualize a difference that is consistent with one strand of the double-stranded DNA. This localization of the DNA gives additional information about the unusual structure of DNA in the complex with RecA protein.
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1145
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Li C, Yu X, Speckhard TA, Cooper SL. Synthesis and properties of polycyanoethylmethylsiloxane polyurea urethane elastomers: A study of segmental compatibility. ACTA ACUST UNITED AC 1988. [DOI: 10.1002/polb.1988.090260209] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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1146
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Shaviv R, Westrum EF, Sayer M, Yu X, Brown RJC, Heyding RD, Weir RD. Specific heat of a high‐Tc perovskite superconductor YBa2Cu3O8−δ. J Chem Phys 1987. [DOI: 10.1063/1.452821] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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1147
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Yu X, Nagarajan MR, Li C, Gibson PE, Cooper SL. Poly(chloropropylmethyl-dimethylsiloxane)–polyurethane elastomers: Synthesis and properties of segmented copolymers and related zwitterionomers. ACTA ACUST UNITED AC 1986. [DOI: 10.1002/polb.1986.090241207] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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1148
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Yu X, Du CL, Li ZL. [Determination of total cranial blood flow with the electrical bioimpedance method]. ZHONGHUA NEI KE ZA ZHI 1986; 25:518-20, 574. [PMID: 3803068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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1149
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Yu X, Nagarajan MR, Li C, Speckhard TA, Cooper SL. Properties of ultraviolet cured polydimethylsiloxane–urea acrylates. J Appl Polym Sci 1985. [DOI: 10.1002/app.1985.070300527] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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1150
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Cui GG, Yu X. Traditional Chinese views on geriatric mental health. Chin Med J (Engl) 1984; 97:291-4. [PMID: 6434261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
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