2076
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Sette F, Wertheim GK, Ma Y, Meigs G, Modesti S, Chen CT. Lifetime and screening of the C 1s photoemission in graphite. PHYSICAL REVIEW. B, CONDENSED MATTER 1990; 41:9766-9770. [PMID: 9993353 DOI: 10.1103/physrevb.41.9766] [Citation(s) in RCA: 63] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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2077
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Ma Y, Rudolf P, Chaban EE, Chen CT, Meigs G, Sette F. Multiple sulfur sites in the Cu(100)p(2 x 2)-S surface structure. PHYSICAL REVIEW. B, CONDENSED MATTER 1990; 41:5424-5427. [PMID: 9994414 DOI: 10.1103/physrevb.41.5424] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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2078
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Wang Y, Zhao A, Ma Y, Yu M, Zhang Y, Dai J, Li S. [Studies on ultraweak luminescence of bacteria]. WEI SHENG WU XUE BAO = ACTA MICROBIOLOGICA SINICA 1990; 30:58-62. [PMID: 2111603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Ultraweak luminescence of Escherichia coli, Bacillus subtilis and Brevibacterium ammoniagenes was measured with high sensitive single photon counting equipment (Made in China). The results obtained from ultraweak luminescence of as above three bacterial strains were as follows: spectral distribution curves, photon emission kinetic curves or emission intensity and its qualitative relationship between intensity and bacterial counts.
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2079
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Ma Y, Marks LD. Bloch waves and multislice in transmission and reflection diffraction. Acta Crystallogr A 1990. [DOI: 10.1107/s0108767389009141] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The consistency between Bloch-wave and multislice approaches to calculating high-energy electron diffraction is investigated in both transmission and reflection cases, the emphasis being upon the latter. It is first shown, in more detail than previously published, that in transmission the two yield identical results. Next, the Bloch-wave approach for reflection is shown to yield a stationary solution in multislice, except for a small effect from the surface truncation. It is pointed out that the multislice approach can be exploited to solve exactly for the reflected wave for an arbitrary surface potential by using it as a Picard iteration solution of the Schrödinger equation. The surface potential scattering is not incidence-angle related and is not significant as might be expected. The introduction of absorption improves the consistency between the two methods. Finally, the stationary solutions are compared with solutions obtained using a top-hat incident wave. The latter approach leads to partially stationary solutions, although it is very hard to identify these.
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2080
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Sette F, Chen CT, Ma Y, Modesti S, Smith NV. Magnetic circular dichroism studies with soft x-rays. ACTA ACUST UNITED AC 1990. [DOI: 10.1063/1.39818] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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2081
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Shattuck MD, Ma Y, Itoh M, Shields H. An ESR Study of Radical Kinetics in L-α-Amino-n-Butyric Acid Hydrochloride Containing L-Cysteine Hydrochloride. Radiat Res 1989. [DOI: 10.2307/3577794] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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2082
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Shattuck MD, Ma Y, Itoh YM, Shields H. An ESR study of radical kinetics in L-alpha-amino-n-butyric acid hydrochloride containing L-cysteine hydrochloride. Radiat Res 1989; 120:430-41. [PMID: 2556732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
On annealing at temperatures near 100 degrees C, carbon-centered radicals migrate to sulfur-centered radicals in X-irradiated crystals of L-alpha-amino-n-butyric acid hydrochloride, CH3CH2CH(NH3-Cl)COOH, containing L-cysteine hydrochloride, SHCH2CH(NH3Cl)COOH. Samples containing 0, 0.5, 1.0, and 1.5% L-cysteine hydrochloride were studied. When no cysteine is present, the carbon-centered radical formed by X irradiation, CH3CH2CHOOH, decays according to a second-order diffusion-controlled rate equation. In samples containing cysteine, the same carbon-centered radicals are formed, but on annealing, they migrate to cysteine, where a perithiyl radical, RSS, is formed. The transfer of carbon-centered radicals to perthiyl radicals follows a pseudo first-order rate equation with an activation energy of 1.15 eV. A decrease in the initial concentration of the carbon-centered radicals or an increase in the initial concentration of cysteine results in an increase in the transfer efficiency. The rate of growth of the perthiyl radical depends on both the initial concentration of cysteine and the initial concentration of carbon-centered radicals. The pseudo first-order rate constant increases when either the initial carbon-centered radical concentration increases or the initial cysteine concentration increases. The mechanism by which radicals move from one lattice site to another in the crystalline material is most likely hydrogen abstraction from a neighboring molecule.
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2083
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Chen CT, Ma Y, Sette F. K-shell photoabsorption of the N2 molecule. PHYSICAL REVIEW. A, GENERAL PHYSICS 1989; 40:6737-6740. [PMID: 9902078 DOI: 10.1103/physreva.40.6737] [Citation(s) in RCA: 120] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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2084
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Ma Y, Sette F, Meigs G, Modesti S, Chen CT. Breaking of ground-state symmetry in core-excited ethylene and benzene. PHYSICAL REVIEW LETTERS 1989; 63:2044-2047. [PMID: 10040748 DOI: 10.1103/physrevlett.63.2044] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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2085
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Ma Y, Stern EA, Li X, Janot C. Patterson analysis of aperiodic crystals. PHYSICAL REVIEW. B, CONDENSED MATTER 1989; 40:8053-8056. [PMID: 9991253 DOI: 10.1103/physrevb.40.8053] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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2086
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Ma Y, Sonveaux E. The 9-fluorenylmethyloxycarbonyl group as a 5'-OH protection in oligonucleotide synthesis. Biopolymers 1989; 28:965-73. [PMID: 2742987 DOI: 10.1002/bip.360280505] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Oligo-DNAs are synthesized on a solid support using the 9-fluorenylmethyloxycarbonyl group as a 5'-OH base labile protection. The synthesis of the pure protected nucleotides, a relevant phosphoramidite-type strategy of coupling, and the optimization of the deprotection steps are described. This new synthetic method is an alternative to the standard protocol that avoids acidic conditions.
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2087
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2088
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Qian M, Stern EA, Ma Y, Ingalls R, Sarikaya M, Thiel B, Kurosky R, Han C, Hutter L, Aksay I. Nickel impurities in the Y-Ba-Cu-O 90-K superconductor. PHYSICAL REVIEW. B, CONDENSED MATTER 1989; 39:9192-9199. [PMID: 9947646 DOI: 10.1103/physrevb.39.9192] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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2089
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Abstract
The Bloch-wave method for reflection diffraction problems, primarily electron diffraction as in reflection high-energy electron diffraction (RHEED) and reflection electron microscopy (REM), is developed. The basic Bloch-wave approach for surfaces is reviewed, introducing the current flow concept which plays a major role both in understanding reflection diffraction and determining the allowed Bloch waves. This is followed by a brief description of the numerical methods for obtaining the results including specific results for GaAs near to the [010] zone axis. A number of other Bloch-wave phenomena are also discussed, namely resonance diffraction and its relationship to internal and external reflection and variations in the boundary conditions and Bloch-wave character, splitting of diffraction spots due to stepped surfaces, which can be completely explained, and the reflection equivalent of thickness fringes.
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2090
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Ma Y, Ma MH. [Current status of the laboratory diagnosis of tuberculous meningitis]. ZHONGHUA JIE HE HE HU XI ZA ZHI = ZHONGHUA JIEHE HE HUXI ZAZHI = CHINESE JOURNAL OF TUBERCULOSIS AND RESPIRATORY DISEASES 1989; 12:49-51. [PMID: 2500260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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2091
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Kwawer GN, Miller TJ, Mason MG, Tan Y, Brown FC, Ma Y. Angular distribution of photoelectrons from silver bromide and metallic silver through the Cooper minimum. PHYSICAL REVIEW. B, CONDENSED MATTER 1989; 39:1471-1477. [PMID: 9948356 DOI: 10.1103/physrevb.39.1471] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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2092
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Radosevich JA, Combs SG, Ma Y, Lee I, Gould VE, Thor A, Schlom J, Carney WP, Rosen ST. Expression of ras oncogene p21 during human fetal development as determined by monoclonal antibodies RAP-5, Y13-259, and DWP. VIRCHOWS ARCHIV. B, CELL PATHOLOGY INCLUDING MOLECULAR PATHOLOGY 1989; 56:337-44. [PMID: 2565631 DOI: 10.1007/bf02890035] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
In this report we describe the expression of the ras proto-oncogene p21 protein in various tissues during normal fetal development. Conventional, formalin fixed and paraffin-embedded sections of normal organs were examined from fetuses ranging 9 to 42 weeks of gestation. Immunohistochemical localization of ras p21 was accomplished using the broadly reactive, mouse monoclonal antibodies RAP-5 and Y13-259. The monoclonal antibody DWP, which is specific for a mutated form of ras p21 having a valine/cysteine at amino acid position 12, was also used. Detectable expression of the p21 protein was seen at different time periods during fetal development depending on the tissue. The expression of ras p21 (as detected by RAP-5 and Y13-259) was noted in a wide range of cell types and tissues; intense immunostaining was noted in epithelial cells of the gastrointestinal tract, exocrine and endocrine pancreas, renal tubules and transitional urotheliem, as well as in other tissues. This immunostaining generally, but not invariably, corresponded with patterns previously reported in benign and/or malignant neoplasms of adult tissues. In most instances ras p21 expression, when present, occurred during periods of rapid growth in given organ systems. However, some actively proliferating fetal tissues such as thymus and spleen, failed to express detectable ras p21 suggesting that factors other than cell cycle may influence its expression. No reactivity with DWP was noted in any of the tissues, suggesting that the mutated forms detected by this monoclonal antibody are not expressed during normal human embryogenesis. These data show that there is regulated expression, and broad distribution of this gene product in normal developing human fetal tissue.
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2093
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Shields H, Haven Y, Hamrick PJ, Ma Y. An ESR study of the radicals in X-irradiated L-alpha-amino-n-butyric acid HCl containing 1.5% L-cysteine HCl. Radiat Res 1988; 116:373-8. [PMID: 2849778] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
After X-irradiation at room temperature, the radicals in L-alpha-amino-n-butyric acid HCl are CH3CH2CHCOOH. The beta- and alpha-hyperfine constants are typical of those found in amino acid radicals. On annealing at temperatures near 100 degrees C this carbon-centered radical in samples containing 1.5% cysteine converts to a perthiyl radical, RCH2S(1)S(2). The g-values for the perithiyl radical are 2.0024, 2.0257, and 2.0557. When the field is in the minimum g-value direction, the hyperfine splittings are 50 G for 33S(2) and 32 G for 33S(1).
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2094
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Combs SG, Hidvegi DF, Ma Y, Rosen ST, Radosevich JA. Pleomorphic carcinoma of the pancreas with osteoclast-like giant cells expressing an epithelial-associated antigen detected by monoclonal antibody 44-3A6. Diagn Cytopathol 1988; 4:316-22. [PMID: 3254809 DOI: 10.1002/dc.2840040409] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
This article describes a case of pleomorphic adenocarcinoma of the pancreas, metastatic to the adrenal glands and liver, that has unique cytological and histological features. Cytology demonstrated numerous mononuclear and multinucleated tumor giant cells as well as numerous osteoclast-like giant cells. These features were also seen in the histological sections, as were numerous clear cells. Electron microscopy demonstrated features suggesting an epithelial origin of the epulis cells. Prominent immunoreactivity with the monoclonal antibody (MCA) 44-3A6 of these cellular constituents was seen in the aspirate and in the tissue sections. These data provide further evidence to support the epithelial origin of these cellular components.
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2095
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Radosevich JA, Gould VE, Ma Y, Lee I, Thor A, Carney WP, Warren WH, Schlom J, Rosen ST. Immunohistochemical analysis of normal and mutated ras oncogene p21 expression in human pulmonary and pleural neoplasms. VIRCHOWS ARCHIV. B, CELL PATHOLOGY INCLUDING MOLECULAR PATHOLOGY 1988; 56:377-83. [PMID: 2567085 DOI: 10.1007/bf02890040] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
In this study we examined 214 cases of primary human pulmonary neoplasms for the expression of a mutated form of the ras oncogene p21 product, recognized by the monoclonal antibody (MCA) DWP. Adjacent serial sections from these same cases had previously been used to demonstrate the frequency of ras p21 expression using the broadly reactive anti-ras p21 MCA RAP-5. Confirmation of the increased expression of p21 was accomplished using MCA Y13-259. The use of adjacent tissue sections from these cases allows the direct comparison of the expression of the mutated and non-mutated forms of ras p21. If reactivity with DWP would prove to be significantly more restrictive than that of the "pan" ras MCAs, RAP-5 and Y13-259, it would lend support to the possibility that DWP (and similar MCAs which detect other specific mutations) could be used to define subsets of these neoplasms based on their specific ras p21 phenotype. Since one would anticipate that the valine/cysteine substitution at position 12 of the ras p21 would occur at only low frequencies in human tumors, our results with DWP are consistent with this hypothesis. As previously reported, RAP-5 reacted with a high proportion of lung tumors (100/214 or 47%). In this report, we demonstrate the selective expression of the mutation recognized by the MCA DWP in only 5% of these same tumors (13/214), and that the expression of this mutated form is not restricted to any of the conventional histological subclasses of pulmonary neoplasms.
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2096
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Ma Y. [The multipotentiality in differentiation and heterogeneity of lung carcinoma cells: analysis of 62 cases of primary lung carcinoma]. ZHONGHUA BING LI XUE ZA ZHI = CHINESE JOURNAL OF PATHOLOGY 1988; 17:176-8. [PMID: 3228906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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2097
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Ma Y, Stern EA. Comment on "Observation of substitutional site preference in a quasicrystal and implication on local structure". PHYSICAL REVIEW LETTERS 1988; 61:901. [PMID: 10039462 DOI: 10.1103/physrevlett.61.901] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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2098
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Ma Y, Stern EA. Short-range structure of Al-Mn and Al-Mn-Si aperiodic alloys. PHYSICAL REVIEW. B, CONDENSED MATTER 1988; 38:3754-3765. [PMID: 9946745 DOI: 10.1103/physrevb.38.3754] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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2099
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Ma Y, Varadan VV, Varadan VK. Scattered intensity of a wave propagating in a discrete random medium. APPLIED OPTICS 1988; 27:2469-2477. [PMID: 20531779 DOI: 10.1364/ao.27.002469] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The present paper aims at a computational scheme to obtain numerical results for the second moment (average intensity) of a wave field propagating in a medium consisting of randomly distributed scatterers, not necessarily simple in shape. A formalism is presented that parallels the diagram method and shows the approximations made in the intensity computation of anisotropic scattering whenever finite size scatterers with a considerable concentration are considered. The back and forth scattering between a pair of scatterers, which has been neglected in the ladder approximation, automatically appears in our formalism taking into account all the multiple scattering between two particles through the pair statistics. Sample numerical results for average intensity scattered by particles are presented and compared to some microwave and optical measurements.
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2100
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