[en] The influence of chemical mutagens and ionising radiation on growth, regenerative capacity of rice callus culture and the effect o9f mutagens on frequency and spectrum of mutant regenerants, derived from calli and determination of approximate semi-lethal dose of each mutagen on rice calli was studied. Intact mature de-husked grains and pieces of primordial particles of four varieties were used as explants in the experiment. Organogenesis was induced using MS media supplemented with agar. After thirty days calluses were subjected to varying concentrations/dosage of mutagens. The effect of mutagens on growth of callus was stimulative in low concentration/doses at short exposure, but in higher concentration/doses at longer exposure it was oppressive. In x-radiation treatment all the studied doses showed only stimulative effect on growth. The effect of mutagenic treatment on regenerative capacity was negative. No specificity was found even between two chemical mutagens of their action on studied characters

[en] This study reports TL properties and the dosimetric properties of natural apatite mineral obtained from Eppawala Apatite ore in Sri Lanka. This mineral was used to study glow curve characteristics by using (a) the powder form of the raw mineral (b) sieved raw mineral and (c) the magnetically separated mineral. The glow curves of magnetically separated apatite showed two peaks. Low temperature peak at 120C, and a high temperature peak at 240C. The emission wavelength of the glow curve is 360 nm. The intensity of the 240C peak become stronger after annealing the mineral to about 180C. Apatite has glow peaks similar to other commonly used TL materials, such as synthetically prepared calcium sulphate:Dy and calcium sulphate:Tm show high intensity peak at 220C and low intensity peaks at 80C and 120C. However, the emission wavelengths of the main peaks are at 428nm and 452 nm for calcium sulphate:Dy and calcium sulphate: Tm respectively. Eppawala apatite mineral showed a linear response to both gamma and beta radiation doses. The results of this study show that there is a fare potential to develop a dosimetric material from Eppawala natural apatite mineral. However, further work has to be carried out to determine the energy response, linearity range of the dose response curve and fading. Finally, the apatite should be fabricated to a chip for use as a dosimeter

[en] Brief description of how nuclear power is used to generate electricity, advantages and disadvantages of nuclear power, and the main factors that should be taken into consideration in dividing to use nuclear power in Sri Lanka

[en] In this Article some of the applications of naturally occuring and artificial isotopes in the study of hydrological problems in Sri Lanka, are discussed. They are the water balance of a small catchment, origin of leakage to the graphite mines at Bogola in Sri Lanka, origin of thermal springs, origin of tropical monsoons and recharge study at Bandarakoswatte are discussed

[en] Laboratory diagnosis of dengue infection is important for the management of the patients. In this study igM capture ELISA using an inhouse method and commercially available kit (MRL diagnostics,USA) was compared to detect diagnostic capability of Inhouse IgM ELISA for provision of diagnostic facilities to the public at an affordable cost. Eighty acute and convalescent serum samples were collected from serologically confirmed dengue patients. Serological confirmation of patients were performed by Haemagglutination Inhibition (HI) assay, gold standard assay for dengue on paired serum samples. All collected acute and convalescent sera were tested by IgM ELISA using the inhouse method and MRL kit. Antigen and conjugate for the inhouse IgM method were prepared in the laboratory. A cocktail of four dengue antigens containing 25 Antigen ELISA units of each type was prepared and used as the assay antigen. Conjugate was prepared using a serum sample with high dengue Anti flavi IgG antibody titre conjugated with Horseradish peroxidase. A prospective study of both IgM ELISA assays were performed using 113 acute sera collected from dengue suspected cases. Overall results showed that 46% and 52% acute sera collected from dengue confirmed patients were positive by inhouse ELISA assay and MRL kits respectively. In the prospective study done using acute sera collected from dengue suspected patients showed that 44% and 52% were positive by inhouse ELISA assay and MRL kits. There was no significant difference in positivity between these two assays. (P=0.18). Inhouse IgM ELISA can be used for provision of laboratory diagnosis of dengue virus infection more than 5 days. The assay is 10 times less costly than using MRL kits as assay antigen and conjugate can be prepared easily in the laboratory

[en] 7 Sup Be and ¹³⁷Cs are two radionuclides present in soil as a result of atmospheric deposition. ¹³⁷Cs has a half-life of 30.2 years and has been extensively used in soil erosion studies. Although 7 Sup Be has a relatively short half-life of 53 days, the potential of using 7 sup Be in estimating erosion rates, associated with short periods of time or individual events has already been recognised. The objective of this study was to measure the activity concentration of these two isotopes in soil using High Purity Germanium gamma ray spectrometry. Thirty five soil samples from different locations in Sri Lanka have been analysed. MOst of these samples (29) were collected from the Western Province while the rest were from remote locations such as Nuwera Eliya, Wasgamuwa, Girithale and Knackles. The gamma counting wad done using cylindrical and Marrinelli beaker geometries and the spectra were analysed using the software package ANGES developed by the International Atomic Energy Agency (IAEA). The efficiency calibration of the system for the two geometries was carried out using the IAEA standards of different densities

[en] Several experiments have been conducted in the 1960's using radioactive phosphorous to study the physiological and growth process of the coconut palm. As a result valuable information on the effective root system and the uptake of fertilizer of the coconut palm, have been obtained. Accordingly precise recommendations on the placement and application of fertilizers were made. Investigations conducted by using stable carbon isotopes have shown the possibility to screen palms for high yield and water-use efficiency. Root water extraction pattern of coconut palms under different soil types and climatic conditions was studied by using neutron moisture probe

[en] The development of SMPRs could make it possible for countries with small electrical grids to use nuclear power. SMPRs are still in the developing stages and none of them have the capability of good plant performance. Most of the SMPRs are in the 300 MWe range and a grid capacity of at least 2000 MWe would be required before such a power plant can be connected to the grid. There is a possibility that SMPRs could generate electricity cheaper coal plants requiring desulphurization. An unexpected increase in coal price and adverse environmental effects could make it necessary to use nuclear power in the future. Qualified manpower is required to plan, build and properly operate a nuclear power plant; and the availability of qualified manpower is a pre-condition for deciding to use nuclear power. There is a possibility that Sri Lanka would be able to use nuclear power in the next 15-20 years and a total dependence upon foreign expertise is neither possible nor desirable. Therefore pre-project activities should be considering such things as teaching nuclear science and engineering in the universities and retraining existing professionals, say from the coal power industry. Adequate emphasis must be given to manpower development and to the need to scheduling this development

[en] Museums, libraries and archives around the world and in Sri Lanka consist of billions of books, textiles, wooden artefacts, etc., whose chemical composition is mainly of cellulose. These artefacts possess high rarity and cultural value and sometimes serve as the keys to uncover ancient knowledge and civilization, Being exposed to climate changes, humidity and atmospheric conditions, insect and fungal attacks over the time, the material tends to deteriorate, posing a threat to their existence for future generations. Gamma irradiation is a well-established technique for both biocidal treatment and remedial conservation by radiation curing with more than 5 decades of application history in cultural heritage, Application of radiation technology for safeguarding of cultural heritage is unprecedented in Sri Lankan context, apart from the radiometric dating, radiographic and nuclear analytical techniques. So the present study is focused on the development of gamma radiation curable chemical formulation to seize the deterioration processes and reinforce the structure of cellulosic cultural heritage artefacts. Considering the possibility of expansion to broad range of cellulosic artefacts, naturally aged paper was selected as substrate material. Chemical formulations containing variable concentrations of alkyd resin, were prepared by mixing it separately with two types of monomers, methyl methacrylate and styrene. The curing was achieved by gamma itrndiation with a dose selected to minimize radiation damage simultaneously with complete curing. The polymer deposition yield was determined by gravimetric measurements and visually examined to identify any alterations to paper material. Adopted samples were advanced to characterization by Scanning Electron Microscopy (SEM) and physical property testing. A positive correlation was observed between the polymer deposition yield and the resin concentration, irrespective of the type of monomer. In comparison to the control, morphological changes indicating the success of curing process was observed in the SEM images and the formulations containing 20% of resin, were proceeded to the physical property testing, based on visual examination. Comparison of tensile strength indicated a significant improvement in the treated samples, with respect to the control. The tearing resistance remained unchanged. With subjected to complementary studies, gamma radiation curable alkyd resin formulations possess a great potential in paper conservation. (author)

[en] Well documented baseline information is indispensable for emergency situations such as nuclear accidents, when an isotopic source is lost, or dealing with debris of reactor powered satellites. Maps of cosmic terrestrial natural and artificial radiation can be constructed by assembling different datasets such as ground and airborne gamma spectrometry, direct dose rate measurements and soil rock samples. In this study an attempt was made to set up baseline radioactivity concentration of Cs-137, U-238 and Th-232 (radionuclides) in soil and grass using gamma spectrometry. Continuous soil and grass sampling was done at two sites in Colombo and one site in Ranpokunugama Housing Scheme for a period of six months. The samples were analyzed for the above three radionuclides using gamma ray spectrometry. The activity concentration of Cs-137, U- 238 and Th- 232 in soil ranged from 0.6- 5.5 Bq per kg, 11.5- 34.9 Bq per kg and 6.4 to 34.2 Bq per kg respectively. The activity concentration of Cs-137 in grass ranged from 5.6- 12.4 Bq per kg