1001
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Ma C, Liu S. Simplified analysis and structural design for ridge mos optical waveguides. APPLIED OPTICS 1990; 29:4435-4440. [PMID: 20577406 DOI: 10.1364/ao.29.004435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
A simplified method is presented for analyzing the optical characteristics of ridge MOS optical waveguides. Equations are derived for calculating the effective refractive indices and the absorption loss coefficients of the E(x)(pq) modes. The computations are performed for air-Au-air/SiO(2)/GaAs/AlGaAs ridge MOS waveguides. To achieve single-mode propagation with low absorption loss, appropriate selection of the structural parameters for this kind of waveguide is discussed.
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1002
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Frambach DA, Ma C, Liggett PE. Modified tubing connections for vitrectomy can be dangerous. ARCHIVES OF OPHTHALMOLOGY (CHICAGO, ILL. : 1960) 1990; 108:781. [PMID: 2350276 DOI: 10.1001/archopht.1990.01070080023017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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1003
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Ma C, Simons RW. The IS10 antisense RNA blocks ribosome binding at the transposase translation initiation site. EMBO J 1990; 9:1267-74. [PMID: 1691097 PMCID: PMC551804 DOI: 10.1002/j.1460-2075.1990.tb08235.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Transposase (tnp) expression from insertion sequence IS10 is controlled, in part, by an antisense RNA, RNA-OUT, which pairs to the translation initiation region of the tnp mRNA, RNA-IN. Genetic experiments suggest that control occurs post-transcriptionally. Here, we present evidence that bears on the control mechanism. Specific ribosome binding at the tnp translation initiation site is demonstrated in vitro. Two mutations that alter tnp translation in vivo are shown to have corresponding effects in vitro. Most importantly, RNA-OUT/RNA-IN pairing is shown to block ribosome binding. In conjunction with the work described in the accompanying paper, we propose that inhibition of ribosome binding also occurs in vivo, and that it is sufficient to account for control. Implications for translational control in analogous systems are discussed.
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1004
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Ma C, Leu TH, Hamlin JL. Multiple origins of replication in the dihydrofolate reductase amplicons of a methotrexate-resistant chinese hamster cell line. Mol Cell Biol 1990; 10:1338-46. [PMID: 2320001 PMCID: PMC362235 DOI: 10.1128/mcb.10.4.1338-1346.1990] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
We recently showed that replication initiates in the early S period at two closely spaced zones in the 240-kilobase (kb) dihydrofolate reductase (DHFR) amplicon of the methotrexate-resistant Chinese hamster ovary cell line CHOC 400. Both of these initiation loci (ori-beta and ori-gamma) have previously been cloned in a recombinant cosmid. In this study, we identified a third early-firing initiation locus (ori-alpha) in the much larger DHFR amplicon of the independently isolated methotrexate-resistant Chinese hamster cell line DC3F-A3/4K (A3/4K). We describe the molecular cloning of this newly identified locus and demonstrate by chromosomal walking that ori-alpha lies approximately 240 kb upstream from ori-beta. Using overlapping cosmid clones for more than 450 kb of DNA sequence from this region of the DHFR domain, we have monitored the replication pattern of the amplicons in synchronized A3/4K cells. These studies suggest that ori-alpha, ori-beta, and ori-gamma are the only early-firing initiation sites in this 450-kb sequence. In addition, we have been able to roughly localize the termini between ori-alpha and ori-beta and between ori-alpha and the next origin in the 5' direction. Thus, we have now isolated the equivalent of three early-firing replicons (including their origins) from a well-characterized chromosomal domain. With these tools, it should be possible to determine those properties that are shared by the origins and termini of different replicons and which are therefore likely to be functionally significant.
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1005
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Zhao J, Liu Z, Ma C, Deng D. [A study on pathogen antigen and serodiagnosis of Malleus and Melioidosis with McAbs]. WEI SHENG WU XUE BAO = ACTA MICROBIOLOGICA SINICA 1990; 30:63-9. [PMID: 2343587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A study on pathogen antigen and serodiagnosis of Malleus and Mlioidosis was made with McAbs which are against Ps. mallei or Ps. pseudomallei. The results showed that (1) Ps. mallei and Ps. pseudomallei express different surface antigen types respectively, and there are antigen overlapping in some degree between them; (2) Epitope 2D4 is common to Ps. mallei and Ps. pseudomallei; (3) The antibody which is similar to McAbs 4D4 or 1A9 might be a common serum antibody of Malleus and Melioidosis; and (4) McAb 3A1 is a high specific one which reacts with Ps. pseudomallei only, and with it, it is possible to resolve the immunological problem of distinguishing diagnosis between Malleus and Melioidosis.
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1006
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Ma C, Sauber JM, Bell LJ, Clark TA, Gordon D, Himwich WE, Ryan JW. Measurement of horizontal motions in Alaska using very long baseline interferometry. ACTA ACUST UNITED AC 1990. [DOI: 10.1029/jb095ib13p21991] [Citation(s) in RCA: 134] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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1007
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Liu WF, Shih JH, Lee JD, Ma C, Lee SF, Lin CH. Effect of the radioprotector WR-2721 on operant behavior in the rat. Neurotoxicol Teratol 1989; 11:199-204. [PMID: 2547148 DOI: 10.1016/0892-0362(89)90059-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The effect of WR-2721 on performance maintained by a fixed-ratio 20 (FR-20) schedule for water reinforcement was studied in male Sprague-Dawley rats. Graded doses of WR-2721 (range 25-100 mg/kg) were administered IP immediately prior to a 60 min test session. WR-2721 had a dose dependent monotonic disruptive effect on FR responding, with significant effects at doses of 50, 75 and 100 mg/kg. WR-2721 also decreased postsession water consumption, but only one significant effect at the highest dose (100 mg/kg). Both slopes of the dose-response regression line are parallel in effect. These data indicate that WR-2721 may affect drinking motivation, which could disrupt operant performance, and WR-2721 affects motor behavior at lower doses than those that depress "motivation" to drink. The log dose-probit analysis on the all-or-none disruptive pattern of pause of responding observed from cumulative records disclosed that the slope of this regression line (s = 1.11) was also almost identical to that of reinforcer decrement analyzed from graded dose-response relationship (s = 1.14) and shared the same estimated ED50's (58.5 and 55.6 mg/kg, respectively). A preliminary study using a variety of pharmacological interventions was also carried out to ascertain if the general functional gastrointestinal disorders produced by WR-2721 may subserve the behavioral deficits. Subcutaneous pretreatments with various selective, peripherally active, gastroprotective drugs [cimetidine (30 and 60 mg/kg), pirenzepine (5 and 10 mg/kg) and domperidone (1, 5 and 10 mg/kg)] 30 min prior to challenge with WR-2721 at dose of 100 mg/kg, demonstrated that these drugs did not yield any apparent significant attenuative effects.(ABSTRACT TRUNCATED AT 250 WORDS)
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1008
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Liu WF, Wei YC, Lee JD, Ma C, Lin CH. Ortho-iodosobenzoic acid: its acute toxicity and neurobehavioral effects in mice. Toxicol Lett 1989; 45:289-98. [PMID: 2919407 DOI: 10.1016/0378-4274(89)90020-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
o-Iodosobenzoic acid (IBA), in a surfactant micellar medium, is a rapid and efficient catalyst for the hydrolysis of organophosphate (OP) esters. Since little is known about the toxicity of IBA, a primary screen of neurobehavioral toxicity was evaluated in male ICR mice. IBA was administered intraperitoneally in a pH 7.4 phosphate buffer solution containing 8% dimethylformamide. The predominant overt signs of toxicity included an immediate and transient writhing reflex and/or persistent spasmodic myotwitching of the abdomen, and conspicuous suppression of orienting/exploratory behavior and emotional defecation. The dose ranges for ED50 of writhing response, suppression of rearing and spontaneous motor activity overlapped at levels of about one-tenth the acute LD50, 742 (633-856) mumol/kg, being 94.9 (74.5-122.5), 69.8 (47.9-105.4) and 71.1 (49.9-101.3) mumol/kg, respectively; the dose ranges for ED50 of abdominal myotwitching and depression of emotional defecation in a novel environment also overlapped but at levels of about one-fifth the acute LD50, being 138.4 (115.3-167.2) and 146.2 (110.7-196.3) mumol/kg, respectively. Morphine (1.25-10 mg/kg s.c.) antagonized the IBA-induced writhing response and abdominal myotwitching in a dose-dependent manner, with a PD50 of 4.2 and 4.9 mg/kg, respectively. The present report demonstrates that acute intraperitoneal administration of IBA produces an intriguing, non-specific behavioral syndrome, probably resulting from nociceptive stimulation. This implies that IBA might be irritating to the skin and mucosa.
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1009
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Starkey JT, Ma C, Ma PF. A study of adenosine deaminase and its conversion factor in human serum. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1989; 253B:65-9. [PMID: 2610146 DOI: 10.1007/978-1-4684-5676-9_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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1010
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Looney JE, Ma C, Leu TH, Flintoff WF, Troutman WB, Hamlin JL. The dihydrofolate reductase amplicons in different methotrexate-resistant Chinese hamster cell lines share at least a 273-kilobase core sequence, but the amplicons in some cell lines are much larger and are remarkably uniform in structure. Mol Cell Biol 1988; 8:5268-79. [PMID: 3244355 PMCID: PMC365629 DOI: 10.1128/mcb.8.12.5268-5279.1988] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
We have previously cloned and characterized two different dihydrofolate reductase amplicon types from a methotrexate-resistant Chinese hamster ovary cell line (CHOC 400). The largest of these (the type I amplicon) is 273 kilobases (kb) in length. In the present study, we utilized clones from the type I amplicon as probes to analyze the size and variability of the amplified DNA sequences in five other independently isolated methotrexate-resistant Chinese hamster cell lines. Our data indicated that the predominant amplicon types in all but one of these cell lines are larger than the 273-kb type I sequence. In-gel renaturation experiments as well as hybridization analysis of large SfiI fragments separated by pulse-field gradient gel electrophoresis showed that two highly resistant cell lines (A3 and MK42) have amplified very homogeneous core sequences that are estimated to be at least 583 and 653 kb in length, respectively. Thus, the sizes of the major amplicon types can be different in different drug-resistant Chinese hamster cell lines. However, there appears to be less heterogeneity in size and sequence arrangement within a given methotrexate-resistant Chinese hamster cell line than has been reported for several other examples of DNA sequence amplification in mammalian systems.
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1011
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Ma C, Bonham RA. Secondary-electron production cross section for 800-eV electron-impact ionization of carbon monoxide. PHYSICAL REVIEW. A, GENERAL PHYSICS 1988; 38:2160-2162. [PMID: 9900616 DOI: 10.1103/physreva.38.2160] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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1012
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1013
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Ma C, Looney JE, Leu TH, Hamlin JL. Organization and genesis of dihydrofolate reductase amplicons in the genome of a methotrexate-resistant Chinese hamster ovary cell line. Mol Cell Biol 1988; 8:2316-27. [PMID: 2841578 PMCID: PMC363429 DOI: 10.1128/mcb.8.6.2316-2327.1988] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
We have recently isolated overlapping recombinant cosmids that represent the equivalent of two complete dihydrofolate reductase (dhfr) amplicon types from the methotrexate-resistant Chinese hamster ovary (CHO) cell line CHOC 400. In the work described in this report, we used pulse-field gradient gel electrophoresis to analyze large SfiI restriction fragments arising from the amplified dhfr domains. The junction between the 260-kilobase type I amplicons (which are arranged in head-to-tail configurations in the genome) has been localized, allowing the construction of a linear map of the parental dhfr locus. We also show that the 220-kilobase type II amplicons are arranged as inverted repeat structures in the CHOC 400 genome and arose from the type I sequence relatively early in the amplification process. Our data indicate that there are a number of minor amplicon types in the CHOC 400 cell line that were not detected in previous studies; however, the type II amplicons represent ca. 75% of all the amplicons in the CHOC 400 genome. Both the type I and type II amplicons are shown to be composed entirely of sequences that were present in the parental dhfr locus. Studies of less resistant cell lines show that initial amplicons can be larger than those observed in CHOC 400. Once established, a given amplicon type appears to be relatively stable throughout subsequent amplification steps. We also present a modification of an in-gel renaturation method that gives a relatively complete picture of the size and variability of amplicons in the genome.
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1014
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Folk JC, Ma C, Blodi CF, Han DP. Occlusion of bridging or avulsed retinal vessels by repeated photocoagulation. Ophthalmology 1987; 94:1610-3. [PMID: 3431831 DOI: 10.1016/s0161-6420(87)33242-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
A technique is described for occlusion of bridging vessels associated with retinal breaks, and recurring vitreous hemorrhage. Argon laser photocoagulation, applied around and to the vessel in repeated sessions, produces scarring and progressive thinning of the retina until laser energy absorbed in the deep pigmented layers can reach the vessel and occlude it. Seventeen patients presenting with vitreous hemorrhage from bridging vessels were treated. Vitreous hemorrhage recurred in only two patients, one of whom had not returned for completion of treatment. The authors conclude that repeated argon laser photocoagulation is a safe, simple, and effective method for preventing recurrent vitreous hemorrhage from bridging vessels.
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1015
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Liu WF, Shih JH, Liu RF, Ma C, Lin CH, Liu CY, Chang CL, Wu MT. Relationship between radioprotective and neuromotor effects of S-2(3-aminopropyl-amino)ethylphosphorothioate (WR-2721) in mice. Neurotoxicol Teratol 1987; 9:333-7. [PMID: 2826981 DOI: 10.1016/0892-0362(87)90027-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The radioprotective and neuromotor effects of WR-2721 were studied in male albino ICR strain mice. The protective activity was evaluated by graded doses of WR-2721 (50-400 mg/kg, IP) against whole body 60Co gamma irradiation at a single maximal lethal threshold dose rad (i.e., 1250 rad). The neuromotor effects of the drug were assayed by its action, at the same dose range as used in the protection assay, on spontaneous motor activity (SMA) and wire hanging performance (WHP). Drug doses were administered 30 min before radiation exposure and neurobehavioral testings. The results showed a dose-dependent increase in radioprotection and an inhibition in the neuromotor tasks. The radioprotective efficacy was seen at doses at which intrinsic neuromotor deficits were detected (100-400 mg/kg). A dose-related parallelism of protective efficacy and neurobehavioral toxicity (i.e., SMA inhibition and WHP disruption) was also observed. The present findings suggest that WR-2721 induces neuromotor dysfunctions along with its radioprotectivity.
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1016
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Peng Y, Guan CF, Xu SL, Lin Y, Tian YY, Ma C, Bao YQ, Wang CB, Ma JR. Effects of laser radiation and photobustion over zusanli on the blood immunoglobulin and lymphocyte ANAE of the healthy aged. J TRADIT CHIN MED 1987; 7:135-6. [PMID: 3448394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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1017
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Clark TA, Gordon D, Himwich WE, Ma C, Mallama A, Ryan JW. Determination of relative site motions in the western United States using Mark III Very Long Baseline Interferometry. ACTA ACUST UNITED AC 1987. [DOI: 10.1029/jb092ib12p12741] [Citation(s) in RCA: 91] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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1018
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Su CT, Wang PH, Liu RF, Shih JH, Ma C, Lin CH, Liu CY, Wu MT. Kinetic studies and structure-activity relationships of bispyridinium oximes as reactivators of acetylcholinesterase inhibited by organophosphorus compounds. FUNDAMENTAL AND APPLIED TOXICOLOGY : OFFICIAL JOURNAL OF THE SOCIETY OF TOXICOLOGY 1986; 6:506-14. [PMID: 3699334 DOI: 10.1016/0272-0590(86)90224-1] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The kinetics of the reactivation of acetylcholinesterase inhibited by isopropyl methylphosphonofluoridate was studied. The reactivators used include nine bispyridinium monooximes and three bispyridinium dioximes. The dissociation constant (Kd) and the rate constant (k2) of dephosphorylation of the complex formed from the organophosphorus acetylcholinesterase (OP-AChE) and the oxime were measured. The reactivation parameters obtained from the in vitro kinetic studies were used to elucidate the structure-activity relationships. The hydrophobic property of a nonoxime substituent at the 3-position on the pyridinium ring can exert a positive effect on their binding affinity to OP-AChE. However, the rate constants (k2) of the nucleophilic displacement of OP-AChE by oximes depend negatively on these physical and structural factors of the oximes. The correlations of the in vivo antidotal efficacy (ED50) of these bispyridinium oximes have been analyzed with their pharmacological properties, e.g., reactivation potency, antimuscarinic activities, and antinicotinic activities. However, no satisfactory correlations were observed. It may be concluded that the detoxication mechanism of poisoning by isopropyl methylphosphonofluoridate is different from those of pinacolyl methylphosphonofluoridate and paraoxon.
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1019
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Ryan JW, Clark TA, Coates RJ, Ma C, Wildes WT, Gwinn CR, Herring TA, Shapiro II, Corey BE, Counselman CC, Hinteregger HF, Rogers AEE, Whitney AR, Knight CA, Vandenberg NR, Pigg JC, Schupler BR, Rönnäng BO. Geodesy by radio interferometry: Determinations of baseline vector, Earth rotation, and solid earth tide parameters with the Mark I Very Long Baseline Radio Interferometry System. ACTA ACUST UNITED AC 1986. [DOI: 10.1029/jb091ib02p01935] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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1020
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Ma C, Su MW, Chang BY, Wu SM, Choo KB, Peng HW, Chong LL, Ng HT. Restriction fragment length polymorphism of the human beta-globin gene cluster: analysis of a beta-thalassemic family in Taiwan. PROCEEDINGS OF THE NATIONAL SCIENCE COUNCIL, REPUBLIC OF CHINA. PART B, LIFE SCIENCES 1986; 10:6-12. [PMID: 3012618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
We have analysed seven polymorphic restriction sites of the human beta-globin gene cluster of six members of a Chinese family with a beta +-thalassemic sibling. The seven polymorphic sites analysed are the HincII site at the 5'-end of the epsilon-globin gene, the HindIII sites in the two gamma-globin genes, two HincII sites within and at the 3'-end of the psi beta 1 pseudogene, the AvaII site in the beta-globin gene and the BamHI site located at the 3' side of the beta-globin gene. The beta thal chromosome has been identified to have a haplotype of +----++ with respect to these seven polymorphic sites. This is also the most predominant haplotype associated with beta +-thalassemia in Mediterranean and Chinese populations (Chen et al., 1984; Orkin et al., 1982). Of the seven sites analysed in this family, four will be useful in prenatal diagnosis of beta-thalassemia in subsequent pregnancies in the family.
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1021
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Herring TA, Shapiro II, Clark TA, Ma C, Ryan JW, Schupler BR, Knight CA, Lundqvist G, Shaffer DB, Vandenberg NR, Corey BE, Hinteregger HF, Rogers AEE, Webber JC, Whitney AR, Elgered G, Ronnang BO, Davis JL. Geodesy by radio interferometry: Evidence for contemporary plate motion. ACTA ACUST UNITED AC 1986. [DOI: 10.1029/jb091ib08p08341] [Citation(s) in RCA: 66] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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1022
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Wong KL, Bitter M, Hammett GW, Heidbrink W, Hendel H, Kaita R, Scott S, Strachan JD, Tait G, Bell MG, Budny R, Bush C, Chan A, Coonrod J, Efthimion PC, England AC, Eubank HP, Fredrickson E, Furth HP, Goldston RJ, Grek B, Grisham L, Hawryluk RJ, Hill KW, Johnson D, Kamperschroer J, Kugel H, Ma C, Mansfield D, Manos D, McCune DC, McGuire K, Medley SS, Mueller D, Nieschmidt E, Owens DK, Paré VK, Park H, Ramsey A, Rasmussen D, Roquemore AL, Schivell J, Sesnic S, Taylor G, Williams MD, Zarnstorff MC. Acceleration of beam ions during major-radius compression in the tokamak fusion test reactor. PHYSICAL REVIEW LETTERS 1985; 55:2587-2590. [PMID: 10032185 DOI: 10.1103/physrevlett.55.2587] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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1023
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Bloor BC, Fukunaga AF, Ma C, Flacke WE, Ritter J, Van Etten A, Olewine S. Myocardial hemodynamics during induced hypotension: a comparison between sodium nitroprusside and adenosine triphosphate. Anesthesiology 1985; 63:517-25. [PMID: 4051212 DOI: 10.1097/00000542-198511000-00007] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Adenosine triphosphate (ATP) has been reported to be a hypotensive agent similar in effect to sodium nitroprusside (SNP). The purpose of this study was to examine and compare the effects of both SNP and ATP on general coronary hemodynamics, myocardial O2 consumption, and circulating catecholamines. Twelve dogs were anesthetized with 1.0% halothane and given either SNP or ATP by controlled infusion to reduce their systemic blood pressure by 50% for a 2-h period followed by a (blood pressure) recovery period. The ATP-induced hypotension was rapid, easily controlled, not accompanied by tachyphylaxis over the 120 min studied, and resulted in an increase in coronary sinus blood flow (CSBF), which plateaued at 260% above control. The increase in CSBF was almost immediate and remained at this elevated level for the duration of the induced hypotension. During the ATP-induced hypotension, there was no change in heart rate or circulating catecholamines. A 60% reduction in myocardial O2 uptake was observed, presumably from the cardiac unloading. In contrast, SNP-induced hypotension required a marked increase in dose over time, did not significantly increase CSBF, did increase heart rate, and resulted in large increases in circulating plasma catecholamines. Neither agent affected cardiac output. ATP-induced hypotension resulted in no change in cardiac lactic acid uptake, while SNP caused lactic acid production, indicating possible cardiac ischemia or cyanide toxicity.
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1024
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Ma C, Smith MA. Physical and genetic mapping of safflower chloroplast DNA : Location of psbA, rbcL, atpA and rrnA. PLANT MOLECULAR BIOLOGY 1985; 4:385-388. [PMID: 24310941 DOI: 10.1007/bf02418260] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
A physical map of safflower (Carthamus tinctorius L.) chloroplast DNA has been generated using SalI, PstI, KpnI and HindIII restriction endonucleases. The circular plastid genome (151 kbp) has the usual inverted repeat. Heterologous probes containing psbA, rbcL, atpA or rrnA structural genes mapped colinearly with spinach and other chloroplast genomes.
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1025
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Ma C, Smith MA. The chloroplast genome of Carthamus tinctorius. Mol Cell Biochem 1985; 68:139-50. [PMID: 3001501 DOI: 10.1007/bf00219378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
A physical map of safflower (Carthamus tinctorius L.) chloroplast DNA has been generated using SalI, PstI, KpnI and HindIII restriction endonucleases. Southern blots to single and double digests by these enzymes were hybridized with 32P-dCTP nick-translated KpnI probes, which were individually isolated from agarose gels. The plastid genome was found to be circular (151 kbp), to contain a repeated sequence of about 25 kbp, and to have small and large single copy regions of approximately 20 and 81 kbp, respectively. Heterologous probes from spinach and Euglena containing psbA, rbcL, atpA or rrnA structural genes were also hybridized with such single and double restriction enzyme digests and mapped on this circular chloroplast genome. The genetic map was found to be co-linear with that of spinach and many other higher plants.
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1026
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Ma C, Smith MA. Construction and mapping of safflower chloroplast DNA recombinants and location of selected gene markers. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 1985; 70:620-627. [PMID: 24253119 DOI: 10.1007/bf00252287] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/1985] [Accepted: 01/22/1985] [Indexed: 06/02/2023]
Abstract
DNA was isolated and purified from chloroplasts of safflower (Carthamus tinctorius L.), digested with HindIII restriction endonuclease, and ligated into the HindIII site of the plasmid pUC9. Recombinant DNAs were isolated from ampicillin resistant white colonies which grew in the presence of the appropriate indicator, digested with HindIII, and then identified by comparison of agarose gel electrophoretic mobilities. HindIII digests of chloroplast DNA were used as a standard. Such recombinants were radiolabeled and hybridized with Southern blots of PstI, SalI, KpnI, and HindIII single and double digests of safflower chloroplast DNA. A physical map was subsequently generated showing the location of each recombinant on the circular plastid genome. Recombinants containing heterologous chloroplast gene markers from spinach or Euglena were also radiolabeled and mapped. The relative mapping positions of these genes are in good agreement with those which have previously been published for spinach and several other higher plants.
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1027
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Smith MA, Ma C. Restriction endonuclease cleavage site map of safflower (Carthamus tinctorius L.) chloroplast DNA. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 1985; 70:32-41. [PMID: 24254111 DOI: 10.1007/bf00264479] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/1984] [Accepted: 09/21/1984] [Indexed: 06/02/2023]
Abstract
The restriction endonucleases SalI, PstI, KpnI and HindIII have been used to construct a physical map of safflower (Carthamus tinctorius L.) chloroplast DNA. This was accomplished by hybridizing Southern blots of single and double digested chloroplast DNA with (32)P-dCTP nick-translated SalI, KpnI and HindIII probes which were individually isolated from agarose gels. The chloroplast DNA was found to be circular and to contain approximately 151 kbp. In common with many other higher plant chloroplast DNAs a sequence of about 25 kbp is repeated in an inverted orientation. The small and large single copy regions separating the two repeated segments contain about 20 kbp and 81 kbp, respectively. The rRNA structural genes were also mapped by Southern blot hybridization and are co-linear with several other plant species.
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1028
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Gelman E, Ma C, Resener M. Farewell to fringe benefits? NEWSWEEK 1985; 105:70-1. [PMID: 10269610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
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1029
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Murad SH, Tabsh KM, Shilyanski G, Kapur PA, Ma C, Lee C, Conklin KA. Effects of verapamil on uterine blood flow and maternal cardiovascular function in the awake pregnant ewe. Anesth Analg 1985; 64:7-10. [PMID: 3966654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Calcium entry blocking drugs may have a role in the treatment of maternal and fetal tachyarrhythmias, as well as for treatment of premature labor. This study was undertaken to assess the hemodynamic effects of verapamil in the awake pregnant ewe. Verapamil, 0.2 mg/kg administered intravenously over 3 min, resulted in the following maternal cardiovascular changes: transient (2 min) but significant decreases in systolic, diastolic, and mean blood pressures, and significant but equally transient increases in central venous pressure and mean pulmonary arterial pressure. Pulmonary capillary wedge pressure increased for 5 min. These results are consistent with the negative inotropic and peripheral vasodilating effects of verapamil. Cardiac output, systemic vascular resistance, and pulmonary vascular resistance were unaffected. Uterine blood flow decreased 25% at 2 min and remained significantly (7-18%) below control levels for 30 min after drug injection. The effects of verapamil on uterine blood flow suggest that it should be used with caution in cases where uteroplacental perfusion is compromised.
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1030
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Ma C, Tyrawska D, Smith MA. Isolation and characterization of safflower (Carthamus tinctorius L.) chloroplast DNA. Mol Cell Biochem 1985; 65:181-8. [PMID: 3982399 DOI: 10.1007/bf00221101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Safflower (Carthamus tinctorius L.) chloroplasts were isolated and purified with the aid of commercially available nylon mesh, differential centrifugation, and DNase I treatment. These chloroplasts were free of nuclei as determined by light microscopy of aceto orcein stained preparations, and similar to those observed by electron microscopy in spinach and many other higher plants, being bounded by a double membrane layer and characterized by the presence of a lamellar system surrounded by embedding matrix, and stacked membranes or grana lamallae. DNA was isolated and purified from such chloroplasts, and characterized with respect to cesium chloride density gradient isopycnic centrifugation, denaturation, renaturation kinetics and restriction enzyme analysis. These studies show that safflower chloroplast DNA is similar to many other higher plant DNAs having a density of 1.700 g/cm3 (G + C = 40.8%), a Tm of 86 degrees C (G + C = 40.7%) and a molecular complexity and genome size of about 10(8) daltons.
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1031
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Liu WF, Hu NW, Chian TF, Ma C, Lin CH, Liu CY, Wu MT. Adverse behavioral effects of the anticholinesterase poisoning protector pralidoxime methanesulfonate. PROCEEDINGS OF THE NATIONAL SCIENCE COUNCIL, REPUBLIC OF CHINA. PART B, LIFE SCIENCES 1984; 8:341-6. [PMID: 6571596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Pralidoxime methanesulfonate (P2S) has anticholinesterase protective properties, but it also has an array of gastrointestinal (GI) symptoms. Because such a symptom would be disadvantageous to occupational workers who handled and used organophosphorus anticholinesterase continuously, and to soldiers who have had oral pretreatment in a situation where anticholinesterase agent poisoning is a possibility, this question was investigated in rats using three behavioral paradigms to evaluate the feasibility of the oral prophylactic regimen. These are: (1) conditioned taste aversion (CTA), (2) operant behavior and (3) spontaneous locomotor activity (SMA); these three behavioral parameters are analogous to toxicant-induced gastrointestinal (GI) disturbances, performance of learned tasks and behavioral arousal, respectively. Dose-response studies of P2S in dose levels of 0.2, 0.4, 0.8 and 1.6 gm/kg (P.O.) were evaluated. The results consistently demonstrated that only the highest dose significantly produced marked decreases in consumption of flavored solution associated with its ingestion, suppressed keypress response maintained under a 20-response fixed-ratio schedule of water presentation, and inhibited SMA. By inference, if CTA, operant behavior and SMA are appropriate paradigms, P2S, on an acute single oral high dose level, would cause GI disturbances, impair task performance and induce sedation in man.
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1032
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Ma C, Mortimer RK. Empirical equation that can be used to determine genetic map distances from tetrad data. Mol Cell Biol 1983; 3:1886-7. [PMID: 6227810 PMCID: PMC370050 DOI: 10.1128/mcb.3.10.1886-1887.1983] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
An empirical equation has been developed that can be used to calculate genetic map distances from tetrad data with good accuracy for distances of up to at least 120 centimorgans.
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1033
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Su CT, Tang CP, Ma C, Shih YS, Liu CY, Wu MT. Quantitative structure-activity relationships and possible mechanisms of action of bispyridinium oximes as antidotes against pinacolyl methylphosphonofluoridate. FUNDAMENTAL AND APPLIED TOXICOLOGY : OFFICIAL JOURNAL OF THE SOCIETY OF TOXICOLOGY 1983; 3:271-7. [PMID: 6628889 DOI: 10.1016/s0272-0590(83)80139-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The antidotal efficacy of bispyridinium oximes against the poisoning by pinacolyl methylphosphonofluoridate can be correlated well with their physicochemical parameters. Good correlation was observed between the efficacy of antagonism against pinacolyl methylphosphonofluoridate and antinicotinic action of these oximes. X-ray structural analysis showed that these oximes possessed structural similarity to nicotine and acetylcholine of nicotinic conformation. A new model of antidotal action, other than reactivation, against the poisoning by pinacolyl methylphosphonofluoridate was proposed for these bispyridinium oximes through nicotinic receptor binding. The antagonistic efficacy of these antidotes against pinacolyl methylphosphonofluoridate may be attributed to their direct antagonism at nicotinic receptor as well as reactivation of inhibited acetylcholinesterase.
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1034
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Ding YL, Pu SS, Wu DZ, Ma C, Pan ZL, Lu X, Miro SG, Yao ZX. Clinical and histological observations on the application of intermingled auto- and porcine-skin heterografts in third degree burns. Burns 1983; 9:381-6. [PMID: 6351972 DOI: 10.1016/0305-4179(83)90100-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Escharectomy and skin grafting with both homograft and porcine skin has become an effective method in treating massive third degree burns. Seventeen patients and 21 operations of intermingled transplantation of auto- and fresh porcine skin heterografts after escharectomy of the severe burn wounds have been carried out since March 1973. Clinical and histological data are summarized, among which we observed the 'fusing phenomena' of auto- and porcine skin heterografts in 6 patients. Vascularization, 'turning red', viability and rejection as well as ways to improve the results of the grafting method are discussed. No vascular communication between fresh porcine skin and the host wound has been observed during the early postoperative period. The cause of 'turning red' is a reddish transudation between the graft and the host wound seen through the thin porcine skin. Based on histological observations, porcine skin is viable after transplantation. With nutritional support apparently coming from the underlying plasma and tissue fluid. Eventually the process of rejection is similar to that of homograft Better results are found with porcine skin grafts 0.4-0.5 mm in thickness placed 0.5-0.75 cm apart. In order to avoid large sloughing wound surfaces less than 20 per cent area of porcine skin coverage is advisable.
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1035
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Rogers AE, Cappallo RJ, Hinteregger HF, Levine JI, Nesman EF, Webber JC, Whitney AR, Clark TA, Ma C, Ryan J, Corey BE, Counselman CC, Herring TA, Shapiro II, Knight CA, Shaffer DB, Vandenberg NR, Lacasse R, Mauzy R, Rayhrer B, Schupler BR, Pigg JC. Very-Long-Baseline Radio Interferometry: The Mark III System for Geodesy, Astrometry, and Aperture Synthesis. Science 1983; 219:51-4. [PMID: 17734328 DOI: 10.1126/science.219.4580.51] [Citation(s) in RCA: 132] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The Mark III very-long-baseline interferometry (VLBI) system allows recording and later processing of up to 112 megabits per second from each radio telescope of an interferometer array. For astrometric and geodetic measurements, signals from two radio-frequency bands (2.2 to 2.3 and 8.2 to 8.6 gigahertz) are sampled and recorded simultaneously at all antenna sites. From these dual-band recordings the relative group delays of signals arriving at each pair of sites can be corrected for the contributions due to the ionosphere. For many radio sources for which the signals are sufficiently intense, these group delays can be determined with uncertainties under 50 picoseconds. Relative positions of widely separated antennas and celestial coordinates of radio sources have been determined from such measurements with 1 standard deviation uncertainties of about 5 centimeters and 3 milliseconds of arc, respectively. Sample results are given for the lengths of baselines between three antennas in the United States and three in Europe as well as for the arc lengths between the positions of six extragalactic radio sources. There is no significant evidence of change in any of these quantities. For mapping the brightness distribution of such compact radio sources, signals of a given polarization, or of pairs of orthogonal polarizations, can be recorded in up to 28 contiguous bands each nearly 2 megahertz wide. The ability to record large bandwidths and to link together many large radio telescopes allows detection and study of compact sources with flux densities under 1 millijansky.
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1036
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Herring TA, Corey BE, Counselman CC, Shapiro II, Rönnäng BO, Rydbeck OEH, Clark TA, Coates RJ, Ma C, Ryan JW, Vandenberg NR, Hinteregger HF, Knight CA, Rogers AEE, Whitney AR, Robertson DS, Schupler BR. Geodesy by radio interferometry: Intercontinental distance determinations with subdecimeter precision. ACTA ACUST UNITED AC 1981. [DOI: 10.1029/jb086ib03p01647] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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1037
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Ma C, Ray WJ. Structural comparisons among the central complexes in the phosphoglucomutase system by means of spectral techniques. Biochemistry 1980; 19:751-9. [PMID: 6444518 DOI: 10.1021/bi00545a022] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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1038
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Ma C. [The sodium hypochlorite method for the photometric determination of berberine]. YAO XUE XUE BAO = ACTA PHARMACEUTICA SINICA 1966; 13:50-4. [PMID: 5952720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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