Authors:M. Kweon, L. Haynes, L. Slade, and H. Levine
Thermal analysis was used to deduce the mechanism of resistance to enzymatic digestion by starches and to account for the extent of resistance at different enzymolysis reaction temperatures. Thermalanalysis was also used to determine the most productive treatment temperature for exploration of the effects of heat-moisture treatment of starches on their subsequent chemical and physical behavior, including enzyme digestibility. The starches were selected according to an experimental design based on a nontraditional description of genetically varied corn starches. As a result, each functional response to heat moisture treatments of the starches adjusted to different moisture contents could be assigned to the relevant causative structural factor in the experimental design.
The effect of various temperature treatments on TL response characteristics of CaSO4: Dy has been investigated for its reusability when the phosphor has been previously irradiated to increasingly higher gamma doses. In practice, annealing at a standard temperature, namely 400 °C, usually precedes the use or reuse of the phosphor. However, the study demonstrates that the phosphor with a previous history of high accumulated doses does not completely retain its original TL response characteristics with 400 °C treatment unless the phosphor is treated at an elevated temperature, namely 650 °C.
Authors:G. Weber, D. David, L. Quaglia, J. Pauwels, and J. Vanaudenhove
Surface treatment on non-ferrous metals are proposed in order to minimize or determine quantitatively the interference of
gaseous contamination. These proposals result from a large number of determinations of superficial contamination on several
materials using microanalysis by nuclear reactions. This work is included in a larger program which aims the certification
of standard materials in their oxygen, nitrogen and carbon contents.
Authors:Marcela Soares, Juliana Mattos, Priscila Pujatti, Alexandre Leal, Wagner dos Santos, and Raquel dos Santos
The proposal of this work was to investigate the effect of the radioactive (NH3)2PtCl2, cis-diamminedichloroplatinum (II) or CDDP* on malignant glioma cells and verify if the low-dose continuous internal radio-chemotherapy
would be able to produce additive effects. The antitumoral activity of CDDP* and the non labeled cisplatin, CDDP, were evaluated
in glioblastoma. Cisplatin was cytotoxic for glioblastoma cells in a dose dependent manner. Treatment with CDDP*, (IC50 = 1.75 ± 0.07 μM), proved to be more potent than using just CDDP, (IC50 = 4.96 ± 0.40 μM). These results suggest that cisplatin is a very potent radiosensitizer evoking a supra additive effect.
Internal radio-chemotherapy treatment based on CDDP* may be useful alternative to reduce the drug concentration required for
effective inhibition of glioblastoma growth.
In-vivo neutron activation analysis (IVNAA) has been used in this laboratory, approximately for the past twenty years, to determine the bone status of humans. For this purpose, the total body calcium (TBCa) is assayed and that is indicative of the bone mineral concentration of the individual. We have effectively used this method to diagnose, understand and monitor the treatment of osteoporosis among elderly women, particularly in post-menopausal women. This paper summarizes the technique and our experience in dealing with osteoporosis.
Authors:Julen Ibarretxe, Gabriël Groeninckx, and Vincent B. F. Mathot
difference in crystallinity ( dashed line ), final result after correction ( dashed-dotted line ), and zero level indicator ( dotted line )
Figure 9 presents the results of the same treatment applied to
Authors:M. Vasilchenko, T. Shakhtshneider, D. Naumov, and V. Boldyrev
Topochemistry of the initial stages of evaporation and dissolution of monoclinic single crystals of paracetamol and phenacetin was studied. Thermal treatment of these crystals showed that the morphology of etch pits depicts the symmetry of etched planes. The shapes of pits formed during chemical etching of the cleavage plane of a paracetamol crystal by different etchants were not similar to each other. The chemical etching of the cleavage plane of a phenacetin crystal resulted in the formation of pits stretched along the same direction, independently of the chosen solvent. An interpretation of this result is suggested, based on the analysis of the anisotropy of the crystal structure and presence of steric hindrance.
Authors:R. C. Eerlingen, H. Jacobs, H. Van Win, and J. A. Delcour
Gelatinisation temperatures as a function of moisture content were determined for potato starch. The native starch was then hydrothermally treated at a temperature 3% (Kelvin degrees) below the gelatinisation peak temperature and at moisture levels varying from 20 to 67% (by weight). Gelatinisation temperatures, temperature ranges and enthalpy values were affected for all treated samples. However, two sample populations could be distinguished: those samples treated under ‘limited’ moisture conditions and other samples treated in the presence of ‘extragranular’ moisture. A two-step hydrothermal treatment further increased the gelatinisation temperature, but the effect of the second step was small in comparison to that of the first.
A locally produced mordenite type synthetic zeolite and its modified form obtained by the treatment with dilute hydrochloric
acid were tested for their cesium uptake characteristics. The two zeolites were compared with other commercially available
synthetic zeolites with respect to their ability to sorb radiocesium from dilute nitric acid solution. The effects of the
changes in the composition of the solution including the concentration of nitric acid, sodium and cesium on the uptake of
cesium were investigated. The results can be used in the removing processor radiocesium from different types of nuclear plant
effluents by these zeolites.
Authors:A. P. Ribeiro, A. M. G. Figueiredo, and J. B. Sígolo
Instrumental neutron activation analysis (INAA) was used to determine metals (Ba, Co, Cr, Cs, Fe, Hf, Rb, Sc, Zn), semi-metals (As, Sb), actinides (U, Th) and rare earth elements (La, Ce, Nd, Sm, Eu, Tb, Yb and Lu) in bottom sediments from one of the ponds of the Sewage Treatment Plant (STP) in São Paulo, Brazil. The results obtained were compared with the concentration determined in a soil profile and in a rock sample, in natura, representing the lithologies of the region, and indicated that only As, Cr and Zn can have their origin associated with the residues disposed around the pond.