Development of a multi-color gas puff imaging diagnostic on HL-2A tokamak

A Multi-Color (MC) gas puff imaging diagnostic has been developed on HL-2A tokamak. This diagnostic can simultaneously measure two-dimensional (2D, radial, and poloidal) electron density and temperature distributions with a good spatial resolution of 2.5 × 2.5 mm² and a temporal resolution of about 100 µs at best in edge plasmas. The 2D electron density and temperature distributions are inferred from the ratios of intensities of three different neutral helium emission lines; therefore, it is also referred to as helium beam probe or beam emission spectroscopy on thermal helium. A compact light splitter is used to split the inlet visible emission beam into four channels, and the specific neutral helium lines of the wavelengths λ₁ = 587.6 nm, λ₂ = 667.8 nm, λ₃ = 706.5 nm, and λ₄ = 728.1 nm are measured, respectively. This MC diagnostic has been experimentally tested and calibrated on a linear magnetic confinement device Peking University Plasma Test device, and the measured 2D electron density and temperature distributions are compared with the Langmuir probe measurements.

Development of beam emission spectroscopy diagnostic on EAST

Beam Emission Spectroscopy (BES) diagnostic based on Neutron Beam Injection (NBI) on the Experimental Advanced Superconducting Tokamak has been developed. This system consists of 16 × 8 channels which can diagnose the density fluctuation in a rectangular area of about 20 × 10 cm² in the cross section, whose radial position is adjustable from the core to edge just by means of changing the angle of the rotation mirror. The spatial resolution is about 1-3 cm according to the diagnosed radial position. The temporal resolution is 1 μs. Space calibration of the diagnostic system is done based on the reversibility of the optical path. The NBI modulation experiment shows the success of BES development.

Biological activity of cadeguomycin. Inhibition of tumor growth and metastasis, immunostimulation, and potentiation of 1-beta-D-arabinofuranosylcytosine

Cadeguomycin retarded growth of sc solid IMC carcinoma in CDF1 mice, and pulmonary metastasis of Lewis lung carcinoma in C57BL/6 mice. The antibiotic enhanced phagocytic activity of murine peritoneal macrophages and IL-1 production by P388D1 cells. Delayed type hypersensitivity was stimulated and interferon was induced by the drug. The results suggest that cadeguomycin inhibits tumor growth and metastasis in association with modification of the immune system. The cytotoxicity of arabinosylcytosine to K562 and YAC-1 cells was markedly enhanced by cadeguomycin in culture. The combined administration of arabinosylcytosine and cadeguomycin displayed potentiation in the inhibition of growth of ip-implanted P388 leukemia and metastasis of sc-implanted P388 leukemia to the regional lymph nodes. Cadeguomycin showed low toxicity for mice.

Inhibition of tumor growth and metastasis in association with modification of immune response by novel organic germanium compounds

The effects of two novel organic germanium compounds, 1-phenyl-2-carbamoylethylgermanium sesquisulfide (PCAGeS) and 1-phenyl-2-carbamoylethylgermanium sequioxide (PCAGeO), on transplantable murine tumors and immune responses were studied. Both drugs showed low toxicity for mice. In culture, neither substance displayed significant cytotoxicity against murine tumor cells L1210 leukemia, L5178Y lymphoma, or IMC carcinoma. Growth of subcutaneously transplanted IMC carcinoma or Meth-A fibrosarcoma was markedly reduced by oral administration of PCAGeS. PCAGeO exhibited a similar but smaller effect on the tumor growth. Pulmonary metastasis of Lewis lung carcinoma was inhibited by oral or intraperitoneal treatment with PCAGeS. The activity of cyclophosphamide or Adriamycin against L1210 leukemia was significantly potentiated by oral administration of PCAGeS. PCAGeS enhanced the delayed-type hypersensitivity response to sheep red blood cells (SRBC) of mice or restored the response suppressed by ascitic IMC carcinoma, but did not significantly affect the formation of antibody to SRBC. PCAGeO similarly stimulated the DTH reaction. Phagocytic activity of peritoneal macrophages was enhanced by oral treatment of mice with PCAGeS. The results suggest that PCAGeS and PCAGeO display tumor-inhibitory activity by modification of the immune mechanism.

Studies on antineoplastic activity of naphthomycin, a naphthalenic ansamycin, and its mode of action

An antibiotic, identical with naphthomycin, was isolated from a soil Streptomyces. The antibiotic displayed significant therapeutic activity by ip administration against murine tumors: Ehrlich carcinoma and IMC carcinoma implanted ip. The maximum increase of life-span was more than 169% in Ehrlich carcinoma, and 128% in IMC carcinoma. The antibiotic exhibited a potent cytotoxicity against murine leukemic cells: P388, L1210, and L5178Y. IC50 was 0.4-1.3 microgram/ml in culture. The activity of naphthomycin was reversed by SH compounds: 2-mercaptoethanol, dithiothreitol, and glutathione. DNA and RNA syntheses were more markedly inhibited by naphthomycin than protein synthesis in L5178Y cells. Approximately 50% inhibition of nucleic acid syntheses was observed at an antibiotic concentration of 2 micrograms/ml. Naphthomycin blocked alkaline phosphodiesterase obtained from L5178Y cells: IC50 was ca. 7.6 micrograms/ml. The antibiotic neither caused metaphase arrest nor prevented tubulin polymerization. The results suggest that the mechanism of cytotoxicity of naphthomycin is the inhibition of various SH enzymes, particularly those involved in nucleic acid biosynthesis. The mode of action is unique in the ansamycin group of antibiotics.