A Novel real-time dosimetry technique based on radiation-induced surface activation.

A novel real-time dosimetry technique based on radiation-induced surface activation (RISA) phenomenon has been proposed that is similar to ultraviolet surface activation known typically in anatase-type titanium dioxide. It has been found that the RISA phenomenon occurs on the surface of an oxidised semiconductor or oxidised metal film by radiation incidence. The RISA dosemeter has the following advantageous characteristics: (1) output of the RISA dosemeter is proportional to the dose equivalent rate in harsh environments, (2) fluctuation of output of the RISA dosemeter irradiated by (60)Co gamma-rays is <2.5% beyond the total dose equivalent of 1.8 MSv, (3) the transient current observed in simple insulators for a few seconds or more after onset of irradiation was not detected in the RISA dosemeter and (4) this dosemeter worked well even at high temperatures.

Hematological characteristics of rats spontaneously developing eosinophilia.

Hematological and genetic characteristics of newly found eosinophilic rats were studied. Hematologically, high blood eosinophil counts started at 6 weeks of age. Almost all 10-week-old rats had eosinophilia with individual counts above 500/microliter and 5 to 100 times the normal level. Proliferating eosinophils had normal morphology. An increase in lymphocyte counts was observed at 5 weeks of age, one week earlier than the onset of eosinophilosis. In bone marrow, proliferation of eosinophils was also observed at 8 weeks of age and thereafter progressed, suggesting a role in the pathogenesis of eosinophilia in this rat. The results of genetic cross experiments revealed the disease to be hereditary. The spontaneously eosinophilic rat therefore warrants attention as a model for studying the underlying mechanisms of human and animal eosinophilia.

Influence of powder characteristics of bulk substance with pharmaceutical processing.

The physicochemical properties of crystals can vary with the crystallization procedure employed in their isolation and purification. Moreover, the success of any direct-tableting procedure is directly effected by the quality of the crystals used in this process. We examined the conventional crystallization method employed in the isolation and purification of octotiamine crystals, the active component of the pharmaceutical compound Neuvita. Our objective was to determine under what crystallization conditions (i.e., supersaturation ratio [pH], temperature, impeller speed) octotiamine crystals with excellent direct-tableting potential could be obtained. Our results indicated that modifications in pH level (from 4.3 to 4.0), i.e., a reduction in the supersaturation ratio, and in impeller speed (from 100 to 78 rpm) are necessary to obtain octotiamine crystals with superior flowability and compressibility compared to the use of the conventional crystallization method. Thus, with these modifications in the conventional crystallization method, octotiamine crystals can be made that show dissolution rates similar to those of the conventionally made crystals, yet which can be manufactured into tablets using a simpler method (i.e., direct tableting). Also, the tableting powder made from the new crystal type proved to be less adhesive than the conventionally made crystal powder. This property attributed to the new crystal type will allow for more stable automated manufacturing than the conventional crystal type would allow.