ABSTRACT
There has been considerable discussion about the influence of high-frequency electromagnetic fields (HFEMF) on the human body. In particular, HFEMF used for mobile phones may be of great concern for human health. In order to investigate the properties of HFEMF, we have examined the effects of 2.45-GHz EMF on micronucleus (MN) formation in Chinese hamster ovary (CHO)-K1 cells. MN formation is induced by chromosomal breakage or inhibition of spindles during cell division and leads to cell damage. We also examined the influence of heat on MN formation, since HFEMF exposure causes a rise in temperature. CHO-K1 cells were exposed to HFEMF for 2 h at average specific absorption rates (SARs) of 5, 10, 20, 50, 100, and 200 W/kg, and the effects on these cells were compared with those in sham-exposed control cells. The cells were also treated with bleomycin alone as a positive control or with combined treatment of HFEMF exposure and bleomycin. Heat treatment was performed at temperatures of 37, 38, 39, 40, 41, and 42 degrees C. The MN frequency in cells exposed to HFEMF at a SAR of lower than 50 W/kg did not differ from the sham-exposed controls, while those at SARs of 100 and 200 W/kg were significantly higher when compared with the sham-exposed controls. There was no apparent combined effect of HFEMF exposure and bleomycin treatment. On heat treatment at temperatures from 38-42 degrees C, the MN frequency increased in a temperature-dependent manner. We also showed that an increase in SAR causes a rise in temperature and this may be connected to the increase in MN formation generated by exposure to HFEMF.
Subject(s)
CHO Cells/radiation effects , Electromagnetic Fields , Micronuclei, Chromosome-Defective/radiation effects , Microwaves/adverse effects , Animals , Bleomycin/pharmacology , CHO Cells/drug effects , Cell Line , Cricetinae , Hot Temperature/adverse effects , Micronuclei, Chromosome-Defective/drug effects , Micronucleus Tests/instrumentation , Micronucleus Tests/methods , Radiation Dosage , Radiation, Nonionizing/adverse effects , TemperatureABSTRACT
Magnetic Circular Dichroism (MCD) of Resonant Inelastic X-ray Scattering (RIXS) of 3d(5/2) --> 2p(3/2) decay (Ho Lalpha1) was measured at the Ho L(III)-edge in Ho3Fe5O12. The MCD-RIXS, in which the intermediate state has the 2p4f(n+1) configuration due to the quadrupolar transition of 2p --> 4f, was also observed at the pre-edge region of the Ho L(III)-edge. The obvious superposition of two peaks, which comes from the high-energy off-resonant Raman scattering and the fluorescence, could be found in both the RIXS and the MCD-RIXS when the energy of the incoming X-ray was 7eV higher than the white line. The dependence of the integration of the MCD-RIXS spectra on the incident x-ray energy could roughly reproduce the MCD of X-ray absorption spectra (XAS).
ABSTRACT
Theoretical and experimental analyses have been performed to examine the position resolution of a proportional counter with a 7-microm diameter carbon fiber as a resistive anode, which is used to encode one-dimensional positions of incident photons according to the charge-division method. These analyses have clearly shown that the carbon fiber is applicable to the position sensing of the order of 100-200 microm as long as the filled gas is pressurized at near 10 atm.
ABSTRACT
An on-line computer system for administration of the radioisotope use has been developed. This system consists of a multi-job type host computer and two sets of personal computers with identification card-readers. The personal computers are employed as terminal devices for radioisotope users. By the use of an identification card, entrance and leaving times are recorded automatically. Furthermore, an easy operation of the personal computer permits users to access to the information of their registered radioisotopes, such as nuclides, chemical forms, updated activities, storage locations, and history of usage. A recording sheet on which those data are printed is provided from the personal computer. After the use of radioisotopes, users can record their data on the recording sheets. These records are used as the input data to this system to update the data of the used radioisotopes. Owing to the concise format of the recording sheet and various sorting programs developed in present work, this system enables us to grasp the exact flow of the radioisotopes from purchase to disposal. Out-put data from high-speed kanji printer can provide many important books which are legally requested to be kept for administration of the radioisotope use.
