7226
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Banin A, Margulies L, Chen Y. Iron-montmorillonite: a spectral analog of Martian soil. JOURNAL OF GEOPHYSICAL RESEARCH 1985; 90 Suppl Pt 2:C771-4. [PMID: 11542022 DOI: 10.1029/jb090is02p0c771] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Light absorption and reflectance by smectite clays containing various adsorbed ions were measured in the UV, VIS, and NIR ranges and compared to Martian dust and surface soil spectra. Structural iron in the octahedral sheet of smectites is responsible for a characteristic absorption feature in the UV at 240-260 nm, resulting from an O2 --> Fe3+ charge transfer that is similar to one observed in the Martian spectrum. Adsorbed iron affects, via crystal field absorptions, the reflectance of montmorillonite in the VIS and NIR (to 1.3 micrometers), causing stronger absorption and higher opacity in the wavelength range 0.4-0.6 micrometer, without developing any specific pronounced absorption feature. In both general appearance and presence of, or lack of, spectral features, the iron-montmorillonite reflectance spectra in the VIS and NIR are similar to the Martian spectra. At present, however, spectral similarity cannot be used as the sole criterion for constraining Martian mineralogy since several other minerals, other than Fe-smectites, show sufficient similitude to the Martian spectra; other properties have to be explored and combined to obtain a definitive identification.
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7227
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Shi WX, Chen Y, Jin GZ. [Effect of l-stepholidine on rotational behavior in rats]. ZHONGGUO YAO LI XUE BAO = ACTA PHARMACOLOGICA SINICA 1984; 5:222-5. [PMID: 6242210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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7228
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Zhou M, Chen Y. [Glutathione peroxidase--an antioxidative enzyme]. SHENG LI KE XUE JIN ZHAN [PROGRESS IN PHYSIOLOGY] 1984; 15:348-351. [PMID: 6544521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
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7229
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Abstract
Examination of Monte Carlo kinetic simulations, based on a realistic set of microscopic rate constants that apply to the end of a microtubule with a GTP cap, suggests that the end of a microtubule alternates between two quasimacroscopic phases. In one phase, the microtubule end has a GTP cap that fluctuates in size; in the other phase, the GTP cap has been lost. These repeated phase changes take place at any given tubulin concentration in a wide range of concentrations. While in the first phase, the microtubule grows slowly; while in the second phase, it shortens rapidly and may disappear completely. These results are closely related to the recent experimental work of Mitchison and Kirschner [Mitchison, T. & Kirschner, M.W. (1984) Nature (London), in press].
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7230
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Zheng YF, Chen MQ, Chen Y, Zhang BZ. [Effect of excitation of the peripheral ends of the abdominal vagus on the release of spleen catecholamines in cats]. ZHONGGUO YI XUE KE XUE YUAN XUE BAO. ACTA ACADEMIAE MEDICINAE SINICAE 1984; 6:206-9. [PMID: 6241050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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7231
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Chen Y, Inbar Y, Raviv M, Dovrat A. THE USE OF SLURRY PRODUCED BY METHANOGENIC FERMENTATION OF COW MANURE AS A PEAT SUBSTITUTE IN HORTICULTURE - PHYSICAL AND CHEMICAL CHARACTERISTICS. ACTA ACUST UNITED AC 1984. [DOI: 10.17660/actahortic.1984.150.58] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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7232
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Carlier MF, Hill TL, Chen Y. Interference of GTP hydrolysis in the mechanism of microtubule assembly: an experimental study. Proc Natl Acad Sci U S A 1984; 81:771-5. [PMID: 6583675 PMCID: PMC344918 DOI: 10.1073/pnas.81.3.771] [Citation(s) in RCA: 130] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
This paper reports an experimental study of the interference of GTP hydrolysis in the mechanism of microtubule assembly, following the model and theory previously published [Hill, T. L. & Carlier, M.-F. (1983) Proc. Natl. Acad. Sci. USA 80, 7234-7238]. Results from dilution experiments show that microtubules depolymerize faster below the critical concentration than expected with a reversible polymerization model. The experimental plot of flux versus tubulin concentration exhibits a slope discontinuity at the critical concentration, in agreement with the theory. Theoretical points calculated by the Monte Carlo method can be fitted qualitatively to the data. A consequence of this peculiar dynamic behavior of microtubules is that the ratio of tubulin dissociation and association rate constants measured, respectively, below and above the critical concentration does not yield the true value of the critical concentration. It is emphasized that the presence of GTP at microtubule ends is necessary to maintain the stability of the polymer.
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7233
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Chen Y. [Cytogenetic study on Turner's syndrome]. ZHONGHUA FU CHAN KE ZA ZHI 1984; 19:18-22. [PMID: 6430656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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7234
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Chen Y, Sun CG, Sun GT, Li Y. [The dormancy types and characteristics of the seeds of medicinal plants]. YAO XUE XUE BAO = ACTA PHARMACEUTICA SINICA 1984; 19:69-75. [PMID: 6464770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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7235
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Boldú JL, Muñoz P. E, Chen Y, Abraham MM. EPR power pattern analysis for cubic sites of Fe3+ in MgO. J Chem Phys 1984. [DOI: 10.1063/1.446437] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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7236
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Chen Y, Hill TL. Use of Monte Carlo calculations in the study of microtubule subunit kinetics. Proc Natl Acad Sci U S A 1983; 80:7520-3. [PMID: 6584870 PMCID: PMC389983 DOI: 10.1073/pnas.80.24.7520] [Citation(s) in RCA: 36] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
GTP-tubulin forms a cap on microtubule ends during aggregation. The bulk of the microtubule is GDP-tubulin. This complicates the usual simple kinetic theory of subunit exchange at microtubule ends to such an extent that Monte Carlo calculations are needed to handle the complications, except in special cases. The Monte Carlo method is introduced here, for this problem, and illustrated with steady-state and transient examples. Monte Carlo transients are needed to simulate dilution experiments. Preliminary results (with M. F. Carlier) have been obtained applying these theoretical procedures to experimental data.
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7237
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Chen Y. [Physiological and pathological research in microcirculation in hyperbaric medicine]. SHENG LI KE XUE JIN ZHAN [PROGRESS IN PHYSIOLOGY] 1983; 14:359-361. [PMID: 6678491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
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7238
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Abstract
Acute torticollis has occurred in epidemics in eastern and northern China since 1975, but has not yet been reported in other countries. A general account of this disease, including its terminology, epidemiology, clinical features, laboratory findings, diagnosis, differential diagnosis, and treatment, is presented. The etiology, though highly suggestive of a virus infection, remains to be determined.
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7239
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Chen Y, Zeeck A, Chen Z, Zähner H. Metabolic products of microorganisms. 222. beta-Oxotryptamine derivatives isolated from Streptomyces ramulosus. J Antibiot (Tokyo) 1983; 36:913-5. [PMID: 6885642 DOI: 10.7164/antibiotics.36.913] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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7240
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7241
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Zhang XZ, Zhou FX, Chen Y. [X-ray study on congenital gonadal dysgenesis (Turner's syndrome)]. ZHONGGUO YI XUE KE XUE YUAN XUE BAO. ACTA ACADEMIAE MEDICINAE SINICAE 1983; 5:43-6. [PMID: 6226385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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7242
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Gonzalez R, Abraham MM, Boatner LA, Chen Y. The correlation of hydrogen diffusion with the relative concentrations of cubic and axial Fe3+ sites in KTaO3. J Chem Phys 1983. [DOI: 10.1063/1.444808] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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7243
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Chen Y, Zheng Z, Hu B, Zhang H, Yang L, Ye W. Study on hereditary variations induced by silkworm DNA--mutagenecity of Attacus cynthia ricini by B. mori DNA. SCIENTIA SINICA. SERIES B, CHEMICAL, BIOLOGICAL, AGRICULTURAL, MEDICAL & EARTH SCIENCES 1982; 25:141-51. [PMID: 7100894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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7244
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Chen Y, Hwang LT, Heller P. Immunosuppression in plasmacytoma: induction of suppressor cells. Clin Exp Immunol 1982; 47:191-6. [PMID: 6212173 PMCID: PMC1536353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Immunosuppression in BALB/c mice with plasmacytomas (PC) is, at least in part, due to increased suppressor activity of splenic adherent cells. A PC subcellular fraction rich in intracisternal A particles, previously shown to have an immunosuppressive effect in normal BALB/c mice, is now shown to exert this effect through the development of splenic suppressor cells. The splenic suppressor cells induced with this subcellular fraction were found to be radioresistant adherent macrophages that suppressed the immune response of normal splenic cells to sheep erythrocytes through a diffusible factor, but did not influence their polyclonal IgM secretion ater LPS stimulation in vitro. These characteristics are identical to those of the naturally occurring suppressor macrophages in mice with PC. Whether the induction of suppressor cells is due to the intracisternal A particles themselves or a factor co-purified with them, remains to be established.
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7245
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Chen Y, Heller P. The mode of action of splenic suppressor cells in murine plasmacytoma. Clin Exp Immunol 1981; 45:514-22. [PMID: 6461449 PMCID: PMC1537407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Polyclonal IgM secretion after LPS stimulation and antigen-dependent antibody production by splenic cells of BALB/c mice with plasmacytoma were found to be markedly reduced. The former occurred without mediation of suppressor cells, probably as the result of a quantitative reduction of mitogen-responsive B lymphocytes. On the other hand, the reduction in the generation of antibodies to sheep erythrocytes in vitro, as determined by the number of PFC, was found to be dependent on the activity of suppressor cells which had the functional characteristics of macrophages. The targets of these suppressor cells were found to be normal macrophages, B and T lymphocytes which were all independently suppressed. A diffusible factor appeared to be responsible for the suppressive effect of the suppressor macrophages interfering mainly with those early stages of the immune response involving antigen-triggered B cell activation.
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7246
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Chen Y. [Pharmacological studies of Cinnamomum cassia bark. Part I. Effects on the blood and cardiovascular system (author's transl)]. ZHONG YAO TONG BAO (BEIJING, CHINA : 1981) 1981; 6:32-4. [PMID: 6210452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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7247
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Hou XD, Chen Y. Amaurotic family idiocy in china. Chin Med J (Engl) 1981; 94:477-82. [PMID: 6791888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
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7248
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Thompson J, Sekula S, Chen Y. Magnetic properties of Ni in MgO; Ni+2 ions and magnetically ordered precipitates. ACTA ACUST UNITED AC 1981. [DOI: 10.1016/0378-4363(81)90350-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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7249
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Zhang Z, Chen Y. On the relationship between the population structure and national economic development in China. SOCIAL SCIENCES IN CHINA 1981; 2:55-83. [PMID: 12312519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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7250
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Tang ZJ, Lao AN, Chen Y, Zhang XX, Wang CG, Zhong FD. [Studies on the active principles fo neuromuscular blocking actions of Cyclea barbata (Wall.) Miers (author's transl)]. YAO XUE XUE BAO = ACTA PHARMACEUTICA SINICA 1980; 15:506-8. [PMID: 7211396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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