Characteristic X-ray spectra are inherently accompanied by the tail spectra in the low energy side when X-rays are detected with a semiconductor X ray detector. The tail spectra of Mg, Al, Si, P, S, Cl, K, Ca, Ti, Cr and Mn KX rays have been observed using two different Si (Li) X-ray detectors. An annular source of55Fe has been used to excite the Mg (1.25 ke V) to Ti (4.5 keV) KX-rays, and54Mn and55Fe sources have been used for the detection of Cr (5.4 keV) and Mn (5.9 keV) KX rays, respectively. Observed intensity ratios of the tail area Nt to the Gaussian X ray peak area Np have exhibited to change remarkably at the Si-K adsorption edge energy 1.84 keV. When X-ray spectra detected with diferent Si (Li) detectors are compared at some specific characteristic X ray, diferent values of Nt/Np intensity ratios as well as different line shapes of tail spectra have been observed. Using a simple model, the thickness of Si layer which generates the tail spectrum has been estimated, i.e., the thicknesses are about 0.05μm for one detector and 0.09μm for the other detector. The generation of the tail spectrum is known to be partially due to the escape of ect of photoelectrons or Auger electrons from the intrinsic region. In this paper, in addition to the above effect, it is proposed that the carrier difusion effect is also an important origin for the appearance of the tail spectrum. Model calculation has been performed for the carrier difusion process, and comparison has been done between the calculation and the observed results with respect to the tail spectral line shape as well as Nt/Np intensity ratio.
Effect of dissolved amino acid on the adsorption behavior of radiozinc to cation exchange resin and montmorillonite was studied in the artificial seawater. The adsorption of radiozinc showed a tendency to decrease in the order of magnitude of the stability constant of zinc-amino acid complex. On the other hand, the adsorption of radiozinc in the presence of alanine on the montmorillonite was increased, presumably because the methyl group which was independent of the coordination of alanine with Zn2+ion had maintained the interaction 'with the surf ace hydroxyl group of montmorillonite.
Using Insulin RIA Kit (double antibody method, Dainabot Co., Ltd.), individual components of error due to pipetting of reagents, bound-free separation and counting were evaluated experimentally and theoretically. They were statistically synthesized to get the total response error relationship (RER) . The resulting RER agreed well with the pooled RER obtained by the method reported previously. This good agreement indicates that individual components of error were reasonably and precisely estimated. Based on this result, contribution rates of individual components of error to the total response error were evaluated. The averaged contribution rates over the range to measure, when pipetting precision, C. V. (coefficient of variation) =0.005, were 64% for counting error, 24% for bound free separation error, and the error related with reagent delivery was only 12%. When C. V.=0.01, however, which is considered normal pipetting precision, the contribution rate for the latter went up to 35%. Effect of poor precision in pipetting on final assay results is so great that much more attention than we usually think of should be paid to pipettes and pipetting techniques.
Distribution and excretion of DL-2- (4- (2-thienylcarbonyl) phenyl) propionic acid (suprofen) were evaluated in male and female rats following intravenous (iv.) injection, of labeled suprofen. The radiometric findings following i.v. administration of 2 mg/kg of3H-suprofen to male and female rats showed similar patterns of blood level and excretion of the radioactivity. Elimination, of3H-suprofen from the blood was rapid; most of the radioactivity Was excreted in the urine and, a portion, inn the feces within 24h nftee injection. After Brats with btliary fistulas were givenn an i.v, dose of 2mg/kg of3H-suprofen, approximately half of the, dose was excreted in the bile during 48 h. The only tissues with concentrations higher than that in they plasma were those involved in metabolism and excretion (liver end kidney) ; other tissue, levels were all very low and there was no evidence of accumulation of drug-related pnateral in any tissue.
Model experiments for a simple and effective trapping device of volatile iodine that is generated during radioiodination of biomacromolecules were performed using an activated carbon fiber filler. Over 99.9% of the radioactivity was trappe4 by the first sheet, when a stream of the volatile radioactive iodine was passed through the layer consisting of several sheets of carbon fiber filter of pore-size 2nm preceded by two or three sheets of urethane foam filter to eliminate the water vapor, Since the carbon fiber filter has very little resistance to the gas flow, the device seems applicable to the small filter chamber for the radioiodination hood.
Liquid (toluene and dioxane) scintillation cocktail containing (methyl-3H) thymidine as a radioactive material was distilled by a rotary evaporator after storage for 0 to 12 months. The solvent obtained by distillation was then purified by several treatments, and the3H-concentration in the solvent after each treatment was determined accurately. The3H-concentration in the rotary evaporatordistillate of the cocktails reached about 0.2% of that of the original scintillation cocktails when they were stored for 12 months. But these radioactive materials could be removed completely from each solvent by several refining treatments: washing with water followed by dehydration with molecular sieves in case of toluene scintillation cocktail, and desiccation by adding excess amount of KOH in case of dioxane scintillation cocktail. It was concluded that the distillation followed by several simple refining treatments was useful to regenerate the refined solvent available for the preparation of liquid scintillation cocktail and also as a preliminary step to dispose of the waste scintillation cocktail.