Radiation effects, plasma

Pulsed plasmas containing hydrogen isotopes can produce bursts of alpha particles and neutrons as a consequence of nuclear reactions. The neutrons are useful for radiation-effects testing and for other materials research. A dense plasma focus filled with deuterium at low pressure has produced 10 neutrons in a single pulse (76) (see Deuterium AND TRITIUM). Intense neutron fluxes also are expected from thermonuclear fusion research devices employing either magnetic or inertial confinement. 

Low-pressure plasma discharges are able to provide significant UV radiation in the range of wavelengths effective in sterilization. It explains the important contribution of UV radiation in plasma sterilization at low pressnres, which has been discnssed in Section... 

Goldman M., and L. Pruitt. 1998. A comparison of the effects of gamma radiation and plasma sterilization on the molecular structure, fatigue resistance, and wear behavior of UHMWPE. / Biomed Mat Res 40 378-384. 

IEEE Nuclear Standards http //www.ieee.org/publications standards/index.html (accessed August 25th, 2010). The IEEE has over 130 standards related to nuclear and plasma science, accelerator technology, fusion, nuclear instruments, plasma science and applications, radiation effects, and reactor instruments and controls. 

In applications where coupling agents are not effective, other methods can be used to modify surfaces. Nonpolar surfaces can be converted to polar surfaces by chemical, radiation, and plasma-induced oxidations, or... 

Nouh, S. A. and Abutalib, M. M., Effect of fast neutron irradiation on the structural and optical properties of Makrofol DE 1-1 CC polycarbonate, Radiation Effects and Defects in Solids Incorporating Plasma Science and Plasma Technology, 165 (11), 845-856 (2010) DOI 10.1080/10420150.2010.481672. 

Microwaves may be used to ionize gases when sufficient power is apphed, but only through the intermediate process of classical acceleration of plasma electrons. The electrons must have energy values exceeding the ioniza tion potential of molecules in the gas (see Plasma technology). Ionizing radiation exhibits more biological-effect potential whatever the power flux levels (2). 

High power pulsed lasers are used to produce plasmas and thus to sample and excite the surfaces of soHds. Improvements in minimum detectable limits and decreases in background radiation and in interelement interference effects result from the use of two lasers (99) (see Surface and interface analysis). 

A 2-h incubation with another PGE2 analogue, nocloprost (9P-chloro-DMPG) protects normal human fibroblasts but has no effect on the survival of colon adenocarcinoma cells exposed to 10 Gy (1000 rad) (218). Nocloprost protects against radiation-induced DSBs in normal cells but not in tumor cells. Moreover, incubation using nocloprost for 2 h after irradiation enhances the rate of DSB rejoining in fibroblasts but not in adenocarcinoma cells. These data possibly reflect a different distribution of PG receptors on the plasma membrane of the two cell types. 

The rates of these reactions bodr in the gas phase and on the condensed phase are usually increased as the temperature of die process is increased, but a substantially greater effect on the rate cati often be achieved when the reactants are adsorbed on die surface of a solid, or if intense beams of radiation of suitable wavelength and particles, such as electrons and gaseous ions with sufficient kinetic energies, can be used to bring about molecular decomposition. It follows drat the development of lasers and plasmas has considerably increased die scope and utility of drese thermochemical processes. These topics will be considered in the later chapters. 

Plasma digoxin levels may decrease when the drug is administered with bleomycin. When bleomycin is used witii cisplatin, there is an increased risk of bleomycin toxicity Pulmonary toxicity may occur when bleomycin is administered with other antineoplastic drugs. Plicamycin, mitomycin, mitoxantrone, and dactino-mycin have an additive bone marrow depressant effect when administered with other antineoplastic drugs. In addition, mitomycin, mitoxantrone, and dactinomycin decrease antibody response to live virus vaccines. Dactinomycin potentiates or reactivates skin or gastrointestinal reactions of radiation therapy There is an increased risk of bleeding when plicamycin is administered witii aspirin, warfarin, heparin, and the NSAIDs. 

Additive bone marrow depressive effects occur when the miotic inhibitor drugs are administered with other anti-neoplastic dragp or radiation therapy. Administration of vincristine with digoxin results in a decreased therapeutic effect of tlie digoxin and decreased plasma digoxin levels. There is a decrease in serum concentrations of phenytoin when administered widi vinblastine... 

---