PURSE 1997

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Embryotoxic effect of plumeria rubra
(University of Peradeniya, 1997-11-22) Gunawardana, V. K.; Goonasekare, M. M.; Gunaherath, G. M. K. B.; Gunatillake, A. A. L.; Jayasena, K
Many plants are well known for their medicinal properties, and traditional medical practice based on plants, forms a substantial part of the health care system in many developing countries. Plumeria rubra, a native of Mexico is a deciduous tree with an abundance of sticky, milky latex. Ethnomedical reports indicate that it has been used as a febrifuge, a purgative, and in the treatment ofleprosy. It is also reported to have hypoglycaemic properties. However, the most widely reported usage of this plant appears to be an account of its activity on reproduction. The fruit, latex and other unspecified parts of the plants have been administered orally as abortifacients, while branches are reported to have been used intra-vaginally to produce abortion. Despite the Ethnomedical information available, studies on biological tests are limited. In this study, a bioassay using pregnant rats was used to verify Ethnomedical claims that Plumeria rubra is an abortifacient. The stem bark of Plumeria rubra collected from locations around Peradeniya was separately and exhaustively extracted with hot water and 95% ethanol, using soxhlet. Subsequently the stem bark was sequentially extracted with petroleum ether (PE), dichloromethane (DE) and methanol (ME). Proven fertile males and virgin female Sprague-Dawley rats were used for the bioassay. Females weighing 180 - 200g were individually housed and their vaginal smears examined daily to determine cyclicity. The females showing regular cycles were mated and the day on which sperms were present in the vaginal smear was designated day-l of pregnancy. Each extract suspended in polyvinyl pyrrolidone (pVP) was administered orally to pregnant rats from day 1 to day 10 of pregnancy. The dose was determined daily according to body weight (g/kg). A treatment group consisted of 10 rats, and a control group of 10 rats received PVP only. All animals were autopsied on day 16 of pregnancy, and the number of pregnant animals in the treated and control groups was noted. Additionally, the number of implantation sites, normal foetuses and corpora lutea were counted. The results were subjected to statistical analysis. In conformity' with the usual Ethnomedical practices, the preliminary studies were carried out with the hot aqueous extract and it was found to be toxic at a dose of3.l g/kg. Also, no antifertility activity was detected. A dose of2.0 g/kg showed equivocal antifertility activity and this prompted studies using other solvents. The hot ethanol extract was found to be significantly active although toxic at a dose of 1.5 g/kg. A lower dose of 0.75 g/kg also showed significant activity and only six of the ten animals were pregnant. In the control group all animals were pregnant and the difference was significant. The PE extract when administered orally at a dose 1 g/kg did not show any activity. The DE and ME extract at doses of 1.3 and 1.5 glkg respectively showed marked effects on pregnancy. At autopsy only one rat from the DE treated group was pregnant while five animals were pregnant in the ME treated group. All animals were pregnant in the control and PE treated groups. The reduction in the number of pregnant rats in the DE and ME treated groups was statistically significant. The results obtained with the DE and ME extracts were reproducible in repeat assays. 168 An off-white solid isolated from the DE extract contained the compound plumieride as the major constituent with some impurities. This compound which is an irridoid glycoside also showed significant activity. Six of the ten treated animals showed implantation sites, but only four of these showed normal foetuses. It was possible to identify a pure compound fulvoplumerin from the PE extract. This compound like the parent extract, was devoid of any activity on reproduction in the rat. Toxic symptoms observed in these experiments included reduced food intake, loss of body weight and diarrhoea. Two deaths were recorded in the DE treated group. The weight loss observed with some extracts which showed significant anti- fertility activity, varied from slight to moderate to large. It.was also observed that treated animals gained weight after dosing was stopped indicating that the toxic effects are reversible. Overall, the results indicate that the stem bark of Plumeria rubra is Embryotoxic causing foetal death and subsequent resorption. Further work should be carried out on Plumeria rubra to determine whether active constituents could be separated from the toxic constituents. In addition, investigations on plumieride are merited in order to determine its role in fertility regulation, and it is essential that an authentic sample of plumieride is tested for anti-fertility activity.
Electron probe microanalysis of carious and noncarious cementum - a preliminary study
(University of Peradeniya, 1997-11-22) Ratnaweera, P. M.; Mendis, B. R. R. N.
In order to compare the distribution of elements in normal and carious cementum with the morphology of the lesions, electron probe microanalysis (EPMA) was carried out. Freshly extracted premolar teeth from subject's aged 40 - 48 years were fixed in 10010formal saline. Six ground sections 100J.Unin thickness were then prepared parallel to the long axis of the tooth. These ground sections contained one or more localised carious lesions of early root surface (cemental) caries. Some sections contained large lesions extending up to dentine. Sections with intact cementum served as controls. For EPMA the sections were covered with a thin layer of gold and subsequently examined in an electron probe operated at 20kv and 18 mA. In several areas of each specimen analysis were carried out for Ca, P, Mg, S, F and Na using K emission of each element. Distribution profiles were obtained from linear scans across the cementum and into the dentine at approximately right angle to the root surface. The electron probe was equipped with three spectrometers (diffracting crystals ADP and RAP) and two elements were usually recorded simultaneously. Results showed that in noncarious cementum Ca and P concentration profiles appear as largely horizontal lines with minor secondary depressions. The Mg profiles ascended gradually from the surface of the cementum to cemnto-dentinal junction. In carious cementum the Ca and P values were larger than in intact cementum (n=2). The concentration in the sub-surface lesions in the cementum varied widely but in most instances the concentrations were lower than in non-carious cementum (n=3). A highly mineralized surface zone or a highly mineralized zone adjacent to the advancing carious front of the cemental carious lesions was not found in this study.
Cow milk allergy
(University of Peradeniya, 1997-11-22) Perera, M. P.; Horadagoda, A; De Silva, C. E.
Cow milk, one of the first foreign proteins encountered by many infants, is one of the most common food allergens. Its mixture of more than 20 protein components have been implicated in a number of possible immunologically mediated reactions. This study was undertaken to determine the prevalence of cow milk allergy among Sri Lankans and to identify the nature of allergic reactions manifested by them. A detailed questionnaire was administered to 3461 fresh cow milk consumers from 17 districts. In this study 386 people (11.6%) who claimed to have shown clinical symptoms which subsided on withdrawal of milk from the diet were considered to be allergic to cow milk. Hypersensitivity reactions to cow milk were reported to provoke symptoms associated with the respiratory system (n=188), gastrointestinal system (n=117), nervous system (n=80), skin (n=46) and the cardiovascular system (n=3). One individual was reported to have shown anaphylactic reactions. In one instance an exclusively breastfed infant was reported to have developed respiratory distress when the mother consumed cow milk and clinical signs have subsided when the mother discontinued cow milk consumption. A total of 334 individuals (86.5%) claimed to have developed allergies within 24 hours after consumption of fresh cow's milk suggesting the prevalence of immediate type hypersensitivity reactions. Fifty-two persons (13.5%) reported that they developed the signs after 2 - 7 days of consumption indicating delayed type hypersensitivity reactions. When compared to results of similar studies carried out in western countries, the prevalence of cow milk allergy is high among Sri Lankans. The nature of the allergic reactions reported and the higher prevalence of immediate type hypersensitivity reactions among Sri Lankans are comparable with other countries.
Changes of microbial biomass in soil after incorporation of rice straw
(University of Peradeniya, 1997-11-22) Nandasena, K. A.; Kumara, L. S. C.
Even though, the microbial biomass in soil is a relatively small fraction, it plays a crucial role in various nutrient transformation processes, which control overall nutrient cycling in the soil-plant system. Mineral nutrients in soil are temporarily trapped and immobilised in soil microbial biomass. Subsequently, decaying microbial biomass releases immobilised nutrients such as C, N, P and S to the labile pool of nutrients in soil. The immobilisation and release of nutrients in a given soil is therefore, dependent upon the nature - quality and quantity - of microbial biomass present in soil. The quality and quantity of microbial biomass is affected by various environmental factors such as available oxygen and decomposable organic matter contents in soil. Main objective of this experiment is to study the effects of organic matter addition (rice straw) on microbial biomass development in soil maintained under arable and flooded conditions. Reddish brown Earth (RBE) soil collected from Mahailuppallama was used. Soil was amended with finely ground rice straw at the rate of 1-% w/w basis. One set of sample was maintained aerobically and other set of sample was maintained in flooded condition to give anaerobic condition. All soil-straw samples filled in glass jars were triplicated and incubated at room temperature in the dark. Sampling was done at 1st day, 2nd, 4th and 8th weeks after incubation. Moist soil equivalent to 20g air died basis from each set of soil samples were analysed for microbial biomass Carbon (C) and Nitrogen (N) by using Fumigation-Extraction method (Brookes et ai, 1985 Vance et at, 1987). During the experimental period, C02 evolution from the soil samples was also measured after absorption to NaOH solution. The changes of microbial biomas were monitored in this experiment by determining biomassC and N. Results showed that the application of rice straw markedly increased soil biomass C over the control soil irrespective to the aerobic and anaerobic conditions. Aerobic and anaerobic conditions imposed in this experiment had no affect on biomass C significantly. However, overall increase of biomass C in straw amended soil can be attributed to the supply of carbon source to the microbial biomass. Biomass N also behaved in a similar manner. Only aerobically maintained, rice straw amended soil samples showed a significant increase of biomass N. This means perhaps, in aerobic condition the quality of biomass (in terms of nitrogen) has changed over the anaerobic treatment. It may be due to the development of low C: N ratio biomass components in soil maintained under aerobic condition. Further, microbial activity was measured by C02 evolution. In this study, microbial activity has been increased substantially in rice straw amended soils irrespective to both aerobic and anaerobic conditions. However, the increase of microbial activity was more prominent in the rice straw amended soil, which maintained aerobically. It can be concluded that the addition of organic matter such as rice straw substantially increase the microbial biomass C and N in the early stages of straw decomposition. The aerobic conditions, in contrast to the anaerobic, may also have an affect on the quality of microbial biomass and the activity in the soil.
Bacterium host cell interaction : effect of Haemophilus somnus on phagocytosis, nitric oxide production and chemiluminescence response of bovine mononuclear phagocytes
(University of Peradeniya, 1997-11-22) Gomis, S.; Godson, D.; Wobeser, G.; Potter, A.
The interaction between bovine mononuclear phagocytes (BMP) and Haemophilus somnus are known to be complex. Using a flow cytometric phagocytosis assay, it was found that logarithmically growing H somnus significantly inhibited the phagocytosis of opsonized S. aureus by bovine alveolar macrophages (BAM) obtained both from healthy calves and from cattle experimentally infected with H somnus. However, neither heat- nor formalin-killed, logarithmically growing neither H somnus nor in vitro passaged H somnus showed any effect on the phagocytic activity of these cells. In contrast to BAM, bovine blood monocytes (BBM), had a significant increase in their phagocytic activity following in vitro exposure to logarithmically growing H somnus. The bactericidal ability of bovine mononuclear phagocytes in interaction with H somnus was studied using two in vitro assay systems measuring nitric oxide (NO) production and chemiluminescence response. H somnus rapidly inhibited the Luminol- dependent chemiluminescence (LDCL) of BBM, and of BAM costimulated with opsonized Staphylococcus aureus. Inhibition of the LDCL response of BBM and BAM was abrogated with either opsonized or killed H somnus. In contrast to inhibition LDCL of BMP, both BBM and BAM infected with H somnus had stimulated production of NO. Using a calorimetric bactericidal assay, it was found that: (1) H somnus was able to survive within BBM in vitro and the kinetics of its survival were similar to that seen in BBM isolated from experimentally infected cattle; (2) treatment of BBM with varying concentrations of (Formula) and E. coli LPS had no effect on the survival of H somnus. Moreover, using ultrastructural studies, and 3H_ uracil incorporation into nucleic acids, it was possible to demonstrate the survival of H somnus in BMP. These results indicate that the ability of H somnus to modulate microbicidal activity of BMP would, in turn, assist the intracellular survival and immunopathogenesis of bovine haemophilosis.
Association between hyperhomocysteinaemia and ischaemic heart disease in Sri Lanka
(University of Peradeniya, 1997-11-22) Mendis, Shanthi; Athauda, S. B. P.; Kenji, T.
The objective of this study was to examine the relation between hyperhomocysteinaemia and ischaemic heart disease in a cohort of Sri Lankan patients with ischaemic heart disease. Serum homocysteine, cysteine and cysteinylglyceine were measured in 54 patients with a definite diagnosis of ischaemic heart disease and compared with those of an age and sex matched control group. Patients with coronary ischaemia had significantly higher mean concentrations of homocysteine and its metabolite cysteine (p <0.01). Of the 54 patients with ischaemic heart disease, 14 (35%) had fasting homocysteine concentrations above the 90th percentile of the controls (odds ratio 3.2, 95% CL l.0- 11.3). Hyperhomocysteinaemia is associated with a three-fold increase in coronary risk
Alveolar bone loss related to age and naturally occurring chronic inflammatory periodontal disease in the Sprague Dawley rat
(University of Peradeniya, 1997-11-22) Arudchelvan, Y; Mendis, B. R. R. N.; Pitigala Arachchi, A. J.; Thattil, R. O.
There has been an increased emphasis on the age changes of the periodontium (Severson et al, 1978). Suitable animal models have been used to study age changes in the periodontium (lve et a1, 1980). An important quantifiable parameter for chronic inflammatory periodontal disease (CIPO) is the loss of alveolar bone (Rowe & Bradley, 1981). The main objective of the present study is to measure the histological loss of the interdental septal alveolar bone height with advancing age and naturally occurring CIPO in the Sprague Dawley rat. Thirty each of three months old, one year old and two year old male Sprague Dawley rats (total = 90) were sacrificed and the interdental area between the right mandibular first molar tooth and the right mandibular second molar tooth was examined with the light microscope using an eye piece graticule. The distance from the cemento-enamel junction (CEl) to the crest of the interdental septal alveolar bone was measured in millimetres. The distance (X±SO) between the CEJ and the alveolar crest in the three months old, one year old and two years old rats were 0.79 nun ± O.Ommm, 0.88 mm ± 0.29 mm and 1.14 mm ± 0.54 mm respectively. There was a positive (r=O.34) linear (y=O.17x + 0.59) and significant (p>O.OI) correlation between the advancing age and the distance between the CEJ and the interdental septal alveolar bone crest. It could be concluded that, the height of the crest of the interdental septal alveolar bone decreases with advancing age. It is similar to the observations of Belting et al. 1953 and Wennstrom et al. 1980 among others. Further, it could be expected that CIPO contributes in some extent to the decrease in the height of the interdental septal alveolar bone. Except for three rats who showed histopathological evidence of vasodilatation of the supracrestal connective tissue, the histopathological preparations of the remainder of the two year old rats showed some degree of disorientation in the arrangement of the supracrestal transeptal fibre bundle groups only. There was no fibre bundle disorientation in the three months old rats and in one-year-old rats.
Aesthetic Restoration of Fractured Anterior Teeth Using Original Tooth Fragment
(University of Peradeniya, 1997-11-22) Vijayakumaran, V.
The purpose of this study is to evaluate the success rate for the restoration of fractured anterior teeth, using the original tooth fragment. This treatment procedure was carried out on patients who visited the Dental Clinic, bringing with them the fractured and detached portion of the anterior tooth. Three patients visited the clinic with the fractured incisal half of the upper central incisor. The other three patients visited the clinic with the fractured full crown of the central incisor tooth (two patients) and the lateral incisor tooth. The incisal half of the original tooth fragment was placed in the correct position, and an internal V-shaped notch bevel preparation was performed within the enamel, on both the incisal edge and the remaining portion of the tooth. All the beveled areas were etched with acid and dried with air. After applying the bonding agent, the light cure composite filling material was placed on the etched area all round. The fractured incisal edge was placed on the remaining part of the fractured ‘tooth in the correct position over the composite material carefully and held firmly during the polymerization of the resin. The other three patients visited the clinic with the fractured full crown of the upper central and lateral incisors. In these patients all fractured teeth were treated endodonticaly in the first stage. In the second stage, a ready made stainless steel post was cemented into the root canal and the fractured original crown was fitted in the correct position using glass ionomer cement (GIC). In the third stage the fracture line was filled with composite as mentioned earlier. The three-year follow-up study showed that this type of treatment was successful in both groups of patients.
Analysing the growth performance of Shores seedings transplanted at diffrent altitudes using anova technique
(University of Peradeniya, 1997-11-22) Gunatilaleke, E. R. M. R.; Wijekoon, P.; Gunatilleke, C. V. S.; Gunatilleke, I. A. U. N.
The relative growth performance of seven species of Shorea (S.affinis, S.cordifo/a, Sidisticba; S.gardneri, Smegistophylla; Strapezifolia and Sworthingtonii) were studied in 3 shade houses located at three altitudinally different sites, viz., Indikada mukalana (125m), Sinbaraja field station (58Om) and Suriyakanda (106Om). The experiment was carried out from 1989 to 1991. For each of the 21 treatments (3 sites? species) 4 replicates, each of 12 seedlings were assigned and they were arranged in a randomized design inside each shade house, under controlled conditions. Eight growth parameters were measured after two years of growth. For each growth parameter the best two-way ANOVA model with site and species (including interactions) as using statistical techniques fit independent variables. In each of these models significant interactions were found. Therefore, pairwise comparisons between treatment combinations were done by using the Tukey's studentized range test. According to these comparisons the final conclusions were made on the growth performance of each species in each site
Adsorption and movement of carbofuran in selected soils of Sri Lanka
(University of Peradeniya, 1997-11-22) Kumaragamage, D.; Gamage, D. A. S.; Samatha, M. M. S. S.; Rathnayake, J. I. L. B.
Carbofuran is an insecticide, which is readily adsorbed to soil particles. Adsorption of carbofuran is a key parameter controlling the extent to which it "ill leach through the soil to ground water. The main objective of this study was to investigate the adsorption and movement of carbofuran in major soil types of Sri Lanka. Carbofuran adsorption was studied in soil samples collected from 20 locations by equilibrating with a carbofuran solution. After equilibration. the supernatant was analyzed for carbofuran and the amount adsorbed was calculated. Movement of surface-applied carbofuran was studied in disturbed (packed) and in undisturbed soil columns.Carbofuran was applied to the surface, after which columns were leached with water and leachate samples were analyzed for carbofuran. 'The relationship between the amount of carbofuran leached and soil properties _was analyzed. Carbofuran adsorption did not show a significant relationship with cation exchange capacity, pH and clay content. A significant quadratic relationship was observed between carbofuran adsorption and organic matter, but the linear relationship was not significant. When regression analysis was conducted separately for soils with pH less than 5.5, the relationship between organic matter and carbofuran adsorption improved. In soils with pH greater than 5.5, such a relationship was not observed. The percentage of carbofuran leached showed a significant negative relationship with soil organic matter content and a significant positive relationship with soil pH. The results indicate that the adsorption of carbofuran is greater and leaching is less in strongly acidic soils with high organic matter contents. Thus, application of carbofuran to such soils. will reduce its effectiveness as a pesticide, but with less ground water pollution and therefore with less adverse effects on the environment
Insects pests and their arthopod natural enemies in a paddy field ecosystem
(University of Peradeniya, 1997-11-22) Bambaradeniya, C. N. B.; Edirisinghe, Jayanthi P.
A research project is currently in progress at Bathalagoda to assess the biological diversity in a paddy field ecosystem. This paper reports the insect pests of paddy and their arthropod predators and parasitoids present during the different phases of the paddy field and growth stages of the paddy plant and in relation to the use of biocides. Insects on vegetation were sampled using a sweep net, a quadrate, a Blower vac suction device and a light trap, while aquatic insects were sampled using a dipper. A total of 43 species of pest insects belonging to 20 families and 7 orders, 94 species of arthropod predators belonging to 34 families and 8 orders together with 27 species of insect parasitoids in 12 families and 2 orders were recorded during four consecutive paddy cultivation cycles. The pest insects were dominated by Hemipteran bugs (18 species in 6 families) followed by Lepidopterans (7 species in 4 families), Orthopterans (6 species in 2 families), Co!eopterans (6 species, 2 families), Dipterans (4 species, 4 families), Thysanopterans (1 species in 1 families) and Hymenopterans (1 species in 1 families). The predatory arthropods were dominated by 48 species of spiders in 11 families followed by Coleopterans (14 species in 6 families), Hemipterans (11 species in 8 families), Odonates (11 species in 3 families). Hymenopterans (5 species in 1 families). Orthopterans (3 species in 2 families). Dermapterans (l species in 1 family) and Phasmids (l species). The insect parasitoids collected consisted of Hymenopterans (25 species, 10 families) and Dipterans (2 species in 1 family). Sampling at 2 week intervals during a paddy cycle indicated that the vegetative stage of the plant harboured the most number of pests, while the grain ripening stage harboured more predators. Application ofbiocides affected both pests and predators and the latter more drastically.
Human pain and kindness: a tract on Buddhist Psychology
(University of Peradeniya, 1997-11-22) Kalansuriya, A. D. P.
According to conceptual categories in current analytical philosophy, the concept of perception is entwined with such other empirical ones as sensation, belief, noticing, truth and knowledge. Nevertheless, in Buddhism, the technique appears to be to move from psychological concepts to ethical values envisioning a qualitative difference in comparison with ethical reasoning in analytical philosophy comprising an analysis of the nature of value words, value terms and value statements. This poster highlights this point.
Fractals in ion conducting polymers
(University of Peradeniya, 1997-11-22) Seneviratne, V. A.; Senadeera, G. K. R.; Careem, M. A.
The concept of fractals, introduced by Mandelbrot applies to many physical, technological and biological processes. Fractal patterns can be seen in nature, for example, in mountains, clouds, branches of trees, etc. Examples for fractals in physical systems are disordered crystals, electrodeposition of ions, and those formed in ion conducting polymers and composite materials. There has been considerable interest on the study of fractals. However, experimental fractals (particularly large size fractals) under laboratory controllable conditions are limited in number. In this experiment the main objective was to grow large size fractals in ion conducting polymers. polymer electrolytes were used to observe the fractal growth. The ionic conductivity and fractal growth of these electrolytes were measured, using samples with different ratios and different amounts of . The growth of clusters in polymer salt complexes can be described by the Diffusion Limited Aggregates model (DLA). Iodine particles form the fractal pattern in the polymer, humidity, and appropriate amounts of and salt act as a main role in the fractal growth phenomena. Fractal growth has also been shown to introduce changes in mechanical, structural and transport properties of the electrolyte
Hypolipidaemic activity of some medicinal plants of Sri Lanka
(University of Peradeniya, 1997-11-22) Wimalasiri, W. R.; Fernando, P. H. P.
Hyperlipidaemia, especially hypercholesterolaemia, causing the deposition of cholesterol in the arterial walls, is a predisposing factor for coronary heart disease (CHD). High Density Lipoproteins (HDL), in contrast, could scavenge the deposited cholesterol and prevent predisposition to CHD. Hence, it is advantageous to lower the serum total: HDL cholesterol ratio by therapeutic or dietary intervention. In this study, two independent experiments were carried out where Allum sativum bulbs, Murrya koenigii leaves, Sida acuta roots, Tinosporacordifolia stems were studied in the first study, and Aegle marmelos roots, A marmelos, Allium sativum bulbs, Murrya koengii leaves and Sida acuta roots in the second study, were investigated for any possible hypocholesterolaemic activity. Hyperlipidaemic male Sprague-Dawley rats were treated with aqueous extracts of above plants, 200 mg/kg orally in the first experiment, and 1 g/kg orally in the second experiment, for six weeks, and bled following a 14 h fast, and the sera were analysed for the lipid profiles using "Randox" cholesterol assay kits. The data were analysed by the t-test. In the first experiment, the total and the HDL cholesterol levels of the control group were 71.04 ± 6.58 and 38.76 ± 3.09 mg/dl, respectively (Total: HDL = 1.83). The test groups administered with the extracts of A. sativum, M koenigii, S. acuta and T. cordifalia displayed total: HDL Ratios of l.63, l. 76, 1.45, 1.70 respectively. In the second experiment, the total and HDL cholesterol levels of the control group were 102.93 ± 42.02 and 32.86 ± 8.23 mg/dl, respectively. (Total: HDL = 3.13). The test groups dosed with the extracts of A. marme/os roots, a marme/os leaves. A sativum bulbs, M konigii leaves and S. acuta roots displaced Total: HDL ratio of l.31, 3.54, 6.70, 1.73 and 1.92 respectively. This studies showed that among the plants tested S acuta roots and marme/os roots were most effective in the reduction in the total: HDL, cholesterol ratio and thereby relieve the risk of CHD.
Experimenting with a household composter
(University of Peradeniya, 1997-11-22) Ariyaratna, S. M. W. T. P. K.; Ketharaswari, P.; Shanthini, R.; Walgama, K. S.
Fabrication, installation, start-up and the consequent execution of a household composting unit occupying only about one square-foot of land space have been experimented. The composter was fed with kitchen wastes from a real household. The method of feeding and the maintenance of the composter required to reach high temperatures in the range of 55°C to 60°C within the composter are reported. Such high temperatures ensured good control on odour nuisance and fly breeding. It also reduces the amount of pathogens and the weed seeds present in the composting mass. The final product of the composting operation can readily be added to the soil to order in enrich the soil properties
Insecticidal compounds from Aglaia species
(University of Peradeniya, 1997-11-22) Kumar, Vijaya
In our continuing programme of screening Sri Lankan plants for insecticidal activity. plant extracts are screened at Peradeniya and at Basle, Switzerland and where activity is observed, bioactivity directed fractionation is undertaken to isolate the active Compound. Our work on Ag/aia apiocarpa, a Meliaceae growing in the Knuckles range led to the isolation of a cyclopentanotetrahydrobenzofuran rocaglamide which showed high insecticidal and herbicidal activity. Studies on a more common species of Ag/aia, A.e/aeagnidea showed it to contain roclagamide as well as four other related compounds of high activity. These compounds have shown activity against a wide range of insect> at low concentration and represent the best results of our screening programme so far. Extracts from this plant could be used for pest control by Sri Lankan farmers and the activity of the compounds themselves indicate that they have the potential for commercial exploitation by the plant protection industry.
In-vitro treatment of polluted water by sawdust
(University of Peradeniya, 1997-11-22) Priyantha, N.; Abeysinghe, T. P.; Keerthiratne, S.
Investigation of the potential ability of economical and readily available naturally occurring substances Such as saw-dust for treatment of poUuted water is performed. In-vitro treatment of water samples with added poUutants, that are found in many polluted waters, reveals that the saw-dust of Albizia Odoratissima ("mara" in SinhaIa) is able to remove many metal ions such as magnesium, calcium, chromium, manganese, iron, cobalt, copper, zinc, cadmium and lead from polluted waters. However, water samples treated with mara saw-dust for colour removal is not clear enough to be discharged into surface water without further treatment. Nevertheless, such methodology offers unique advantages of treatment of polluted water in developing countries.
Morphometry of the Permanent Maxillary Incisors using Clinical and Radiological Methods- A Preliminary Study
(University of Peradeniya, 1997-11-22) Jayawardena, J. A. C. K.; Chandrasekare, M. S.
Morphometric studies using clinical and radiological methods were carried out in the maxillary central and lateral incisors of adult females ranging in age from 25 to 65 years. The teeth were collected from the Dental Clinics during routine dental extractions at the Peradeniya and Kandy General Hospitals. The height (TH) of the individuals was measured at the time of tooth extraction. The study sample consisted of 20 permanent maxillary central incisors and 20 permanent maxillary lateral incisors. The measurements taken were the total tooth length (ITL), crown length (CL), root length (RL) and the width of the pulp. Periapical radiographs of all teeth were taken using the standard technique. Both clinical and radiological methods were used in the measurement of the central incisors and onJy the clinical method was used in the measurement of the lateral incisors. A dental venire calliper and an eyepiece micrometer graticule fitted to a microscope were used in these measurements. The data collected were analysed to find out the relationship between the CL and RL; ITL and TH; and RL and TH. The clinical method showed a relationship of 1:1.1 and 1:1.4 in the crown length and root length ratios for the central and lateral incisors respectively. A ratio of 1:125 was observed in the RL and TH of both incisors and CL and TH of central incisors. The ratio of CL and TH in the lateral incisors was 1:143. The ratio of TTL and TH for the central and lateral incisors was 1:63 and 1:67 respectively. The measurement of the clinical and radiological methods did not show a significant difference in the RL. The width of the pulp chamber measured at 3 .levels in the radiographs showed a gradual reduction from the 25 - 35 years to 36 - 45 years. The data observed in this study will be useful in the assessment of the size of the root canals in incisors in endodontic treatment planning.
Periodical changes in soil reaction due to incorporation of green manure to a degraded tea soil of the mid-country of Sri Lanka
(University of Peradeniya, 1997-11-22) Jayakody, A. N.
Some of the lands under tea in the mid-country of Sri Lanka were abandoned since three decades as marginaUdegraded lands due to their poor performances. Soil acidity has been identified as a decisive factor for low soil fertility. For reclamation of such lands, application of liming is frequently advocated. However, as much of these lands are allocated to poor settlers , the procedure of liming is less appropriate. This study has attempted to evaluate the effect of green manures in reducing the acidity of a degraded tea soil in view of reducing the cost of liming. A pot incubation experiment was conducted by treating the soil separately with Cao, Ipil-Ipil (Leucaena /eucocepha/a) , Gliricidia (Gltricidia sepium) and WiJdsunflower (Tithonia diversifolia) green manure at a rate representing 5 t ha -1. The duration of the incubation was 12 weeks and soil samples were drawn at 1Sl, 2nd, 3rd, 4th ,8th and 12th week sub~uent to incorporation of materials.The samples were checked for pH. W- and Al +- saturations as well as pH buffering fluctuations. Based on the results it could be concluded that the green manures used have made a significant contribution in reducing the acidity of the soil including the Al3+-saturation. However, there were hardly differences between the green manures. No change was recorded pertaining to the pH buffering behavior of the soil as well. The overall effect in increasing the pH by green manure was around 1 unit where as the effect by Cao was 1.6 units. Hence there is a possibility of partial substitution of liming materials with appropriate green manures. It is useful to study the effectiveness of such combinations in the future.
A preliminary study on epidemiology of gastrointestinal nematodeasis in goats managed under village conditions in the dry zone of Sri Lanka
(University of Peradeniya, 1997-11-22) Paranagama, W. D.; Rajapakse, R. P. V. J.; Faizal, A. C. M.; Horadagoda, N. U.
Gastrointestinal nematode infection is identified as a major constraint to the development of the goat industry in tropical and subtropical countries including Sri Lanka. Strategies such as chemoprophylaxis and grazing management based on parasite epidemiology are used in the control of the infection. In this presentation, we describe the findings of an ongoing epidemiological study on gastrointestinal nematode infection in goats in the dry zone of Sri Lanka aimed at developing a strategic anthelmintic protocol to control the infection as an alternative to the ad hoc treatment practised currently. Two herds of goats managed under extensive system in the North Central Province were used for this study. The farms were visited monthly from May 1996 to February 1997, and on each visitthe animals were examined clinically and samples were collected for haematology and for the determination of faecal egg counts. The pasture contamination was assessed by considering the worm burdens of the tracer animals. The body weight of the animals was also measured during these visits. During the period under study, the faecal egg counts remained at a very low level during the months of May and June, then gradually increased in the subsequent months to show a significant rise from October that peaked in November. This was followed by a marginal decline in December. It was also noted that the trend in the faecal egg count during may to December mirrored the rainfall pattern for this period in the experimental area. Further, the increase in the faecal egg count was associated with decline in the haemoglobin and packed cell volume, indicating a chronic blood loss due to the parasitic infection. The worm burdens indicate a distinct seasonality in the availability of pasture larvae where low contamination was observed in June followed by a significant increase in the availability during October and November. Three genera of nematodes namely, Trichostrongylus, Oesophagostomum and Haemonchus were identified, with predominance of the latter genus.

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