PhD

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    A Case study of selected locations regarding the reasons for school non-attendance and the implications for agricultural development in Sri Lanka
    (University of Peradeniya, 1982) Ranmuthugala, Janaki Devi
    This case study of selected locations regarding the reasons for school non-attendance and the implications for agricultural development in Sri Lanka, has been dealt with under three main headings: 1. The influence of farmer education level on the adoption of modern farming practices. 2. The influence of schooling on children's attitudes towards agriculture, measured by job preference, the studying of agriculture as a subject in school and knowledge of agriculture. 3. Reasons for school non-attendance. All tests were run in respect of schooling, location and sex separately. The findings and recommendations presented here are limited to this case study only and should not be considered as conclusive or general. Data, tests and analysis have revealed four significant relationships which led to the investigation into the reasons for school non-attendance. The relationships are: 1. A positive relation between correct adoption of modern farming practices and farmer education level. 2. A positive relation between dropping out of school and preference for agricultural occupations. 3. A positive relation between dropping out of school and the studying of agriculture in school. 4. A positive relation between schooling and knowledge of agriculture. The indications are that school non-attendance will have a negative effect on farmer education level, which in turn will have a negative effect on the future of agriculture in the country. Therefore an investigation into the reasons for school non-attendance is justified. In this study the statistical tool used to assess the statistical significance of the data was the chi square test. As regards recommendations the two broad objectives are: 1. To improve the status and quality of the school agriculture programme 2. To minimise dropping out of school in Sri Lanka, It is hoped that while attempting to achieve these objectives the long range objective of attempting to achieve agricultural development in Sri Lanka could be somewhat met. Fig. 1 MAP OF SRI LANKA SHOWING STUDY LOCATIONS
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    A Classification method for optical phenomena of cat's - eyes and stars in minerals
    (University of Peradeniya, 2011) Kumaratilake, W. L. D. R. A.
    In gemstones, needle-like inclusions originate by crystallization of exsolved impurities which occupy structurally favourable specific crystallographic directions in the host mineral during cooling. Countless sub-microscopic needle inclusions near the surface of a cabochon-cut gemstone scatters and reflects light and forms an image that can be described as an optical-loop called a Cat’s-eye. Two or more optical-loops cross each other and form a star effect or a network of stars in gemstones. Cat's-eyes and formation of stars and star networks are phenomena that are least explored areas in gemmology. Objective of this study is to develop a classification method of cat’s-eye and star phenomena applicable to all gem minerals, revealing the effects in profound detail. The study introduces quantitative and qualitative classifications to aid systematic study of cat's-eyes and stars. The quantitative approach (a) reduced the gamut of least explored cat's-eyes and stars into mere eighty nine types, a stereogram and a code visually illustrating complex star-networks analytically and the stereogram enabling the decoding of codes, (b) surfaced many missing links of cat's-eyes and stars laying a platform for new discoveries like sinhalite cat’s-eye. The qualitative comparison scale portrays the quality of a cat’s-eye/star from a commercial standpoint and determines the subjective value addition of the stone. Both quantitative and qualitative research methodology was utilised to devise the classifications. Hypothesis test was carried out from observational study of needle inclusions including those given in previous literature. The result is significant that needles orient parallel to each other and parallel to symmetry-axes-of-rotation of the host crystal and form the optical-loops perpendicular to those even in rough gemstones. In a fashioned cabochon (sphere) an optical-loop moulds into a circular loop-plane, and | hovers above the surface of the stone at a specific distance. This hovering-distance (d) is determined by the Wuthrich’s equation d = 1/2(n-1) mm which relates to the radius of the sphere (r) and the host refractive index (n). Several symmetry-axes-of-rotation produce angled loop-planes which crisscross to form a star-network. To better understand the effect, the study utilized the relation of cat’s-eye and star phenomena to the host crystal symmetry. The quantitative model developed here used this relation and incorporated the loop-plane as an extra symmetry element in the host stereogram. Model’s parameter is the formation of loop-planes perpendicular to symmetry-axes-of- rotation and the variable is the component symmetry-axes-of-rotation, one hundred and six in total within the ¢hirty two symmetry classes. The symmetry-axes-of-rotation are categorized into stand-alones (e.g. Ag), sets (e.g. 6A), and combinations (e.g. A42Az, 6A24A33A4). The stand-alones produce twenty seven cat’s-eyes, and both the sets and combinations yield sixty two star-networks, which is an exhaustive number for entire range of minerals. The total of eighty nine cat’s-eye and star effects has been uniquely identified and a code has been developed to document and classify each one of those on the basis of component symmetry-axes-of-rotation producing the effect. Thus, a four- level and four/eight/twelve-digit code has been proposed in the classification. Many gemstone examples were fitted into the coded classification and this included speculations. However, Sri Lankan star sapphire showed some inconsistency and additional data had to be gathered to improve it. Certain twin crystals display symmetries which deviate from their simple crystals and the new classification scheme is consistent with:such compound crystals too. New scheme was also applied to star sapphires showing polyasterism to uncover the details of displaced sections of those crystals produced by deformation. The classification was finally applied on man-made fibre-optic cat’s-eye material (amorphous) to learn the commercial manufacture of the star stones. A qualitative-model was developed to compare qualities of cat’s-eye/star phenomena. The parameter is the hovering distance d of the phenomena whilst keeping constant the radius (r) of the stones under comparison. Subjective variables were the three quality factors of the comparing phenomena - intensity, definition and colour. To represent qualities of entire range of known phenomena a sample of twenty eight cat’s- eye/star species were selected with radius r = 5mm. The quality factors of seven commercially accepted species were benchmarked and the benchmarks were utilized to develop a comparison scale. Comparison scale demonstrates relative position of a given cat's eye/star with respect to a benchmark.
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    A Comparative study on the concept of sukhavatibhumi in sukhavativyuha sutra
    (University of Peradeniya, 2006) Sankichcha, Rev. Nepalaye
    This dissertation consists of four chapters. 1. Aspecial study on Sukhavativytha Sitra. 2. A comparative study on Sukhavati-Bhimi and the Nibbanic concept in Theravada tradition. 3. A comparative study on Sukhavati-Bhumi and the concept of the final goal of Madhyamika sect or Nihilism. . 4. Summary and conclusion The first chapter examines the background that led to the emergence of "Sukhavatibhimi” (the land of bliss) and "Amitabha Buddha" concepts. Then it discusses the summaries of Mahasukhavati (Larger Sukhavati), Culasukhavati (Smaller Sukhavati) and Amitayur-dhyana (meditation on Amitayur) Sutras which are the main sources of Sukhavati tradition and their editions, commentaries, Chinese and Tibetan translations. Thereafter, it compares larger and smaller Sukhavativythas; discusses the history of Sukhavati sects that prevailed in China and Japan; includes information of pure and impure worlds, the land of bliss as described in the Sukhavativythas, critical analysis of the land of bliss, the concepts of devotion and rebirth as depicted in the Sukhavativythas and the land of bliss mentioned as the ultimate goal in other Mahayana Sitras beside the Sukhavativytihas. Here a special attention is given to the description of the land of bliss. Also I stress upon its modern interpretations as the metaphorical depiction of the mental development by Suzuki (a Japanese scholar) and master Hui- Neng (the sixth patriarch of Chinese Chan sect). The second chapter especially discusses Nibbanic concept of Theravada Pali tradition besides dealing with the concept of Nibbana (emancipation) in Mahayana tradition in India and other sects connected to it. Besides, this chapter contains the theories of various scholars on Nibbana and the path leading to Nibbana. Moreover, it also compares the concepts of ‘the land of bliss' and ‘Nibbana’ and the concepts on paths leading to Nibbana as depicted in these two traditions. Here it is asserted that being born in the land of bliss is similar to acquiring the mental development through Anagami fruition, the third stage on the way to Nibbana as described in Theravada. First part of the third chapter deals with the main points of Madhyamika philosophy and then it is compared with the concept of the final goal as described in Sukhavati tradition. Accordingly, the chapter comprises of the critical discussions on Nagarjuna (the founder of Madhyamika school), the history of this tradition that prevailed in India, China, Tibet, Japan and Korea, the method used by Nagarjuna to express the theory of emptiness, Svatantrika and Prasangika interpretations of Madhyamika, the modern interpretations of these two modes, logical form of catuskoti, the religious and philosophical meaning of emptiness, the forms of emptiness, the idea of emptiness in Yogacara school, the emptiness in Madhyamika that prevailed in China and Japan. The emptiness, discussed here is understood according to the theory of Paticcasamutpada (the theory of dependent arising) and it needs to be realized through the wisdom (Praja) and realizing emptiness is as attaining Nibbana in Madhyamika tradition. The final chapter contains the summaries of each chapters and their conclusions arrived with a thorough analysis. Last but not least, it also compares all concepts of the ultimate goal as depicted in these three traditions.
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    a Complete and balanced fertilizer recommendation based on a systemic approach for cauliflower (Brassica Oleracea L. Var. Botrytis)
    (University of Peradeniya, 2006) Kirthisinghe, J. P.
    Site-specific fertilizer management is a modern approach used with the intention of increasing the fertilizer use efficiency, maximizing profitability and minimizing negative environmental impacts. The commonly used general fertilizer recommendations for vegetable crops in Sri Lanka are based on crop response experiments, which do not consider the variability of soil fertility, and are often limited to the supply of N , P and K. T h e soil-test based fertilizer recommendation introduced by the Department of Agriculture (DOA) does not include secondary and micronutrients. In the above context, the objectives of the present study were to: a) evaluate the fertility parameters and nutrient status through a systematic approach combining soil analysis, fixation studies and greenhouse nutrient surveys and, (b) formulate and test a site- specific fertilizer recommendation for cauliflower (hybrid variety 'Fuji') in three experimental sites. Demand for cauliflower as a vegetable has increased over the last decade. The average yield of cauliflower, however, has come to a plateau even after introducing new high yielding varieties to Sri Lanka. Low productivity due to low fertility of soils and the unbalanced fertilization arc some of the identified reasons for the yield stagnation of vegetable crops. The experimental sites were located in the dry zone at Pclwehera (Reddish Brown Earth; Alfisol), the intermediate zone at Dodangolla (Immature Brown Loams; Inceptisol) and the wet zone at Gannoruwa (Immature Brown Loams; Insceptisol) of Sri Lanka. Soils were analysed using a three-step extraction method to evaluate the available nutrient status; ASI solution extraction for P , K, Cu, Fe, Mn and Zn, 1 MKC\ extraction , Mg and Na, and extraction for B and S contents. Nutrient contents were compared with the established optimum and critical values to identify deficiencies. Fixation studies conducted for P, K, Cu, Zn, Fe, Mn, S and B were used to identify the fixation capacity of the soils for these nutrients and to calculate the amount of additional fertilizer to b e supplemented when fixed or unavailable. An optimum fertilizer recommendation was formulated for each soil and was tested in the greenhouse using a modified missing element technique using Sorghum as the indicator plant, and in the field using cauliflower variety 'Fuji' as the crop. The initial soil analysis indicated deficient levels of N, P, K in all three locations; deficient levels of Ca, S, B, Mn, Mo at Dodangolla site and deficient levels of Ca, B, Zn, M o at Gannoruwa site. The optimum recommendation formulated for each soil consisted of t h e deficient nutrients at rates adjusted based on the fixation capacities for nutrients. T h e optimum treatment gave the highest dry matter yield while the low "N, low P, or low K fertilizer treatments gave significantly (p<0.05) lower yields in the greenhouse experiment in all three soils. In the field, the average cauliflower curd yield varied between 129.8-263.7 g per plant (5.19-10.55 mt ha'1 ) with the optimum treatment, which was significantly higher ii (p<0,05) than the other corresponding fertilizer treatments. The results indicated that the K influenced the curd yield than any other single nutrient. The results of field experiments therefore indicate the importance of diagnosing of nutrient problems in soils prior to cultivation and site-specific fertilizer management for cauliflower. Benefit Cost Ratio analysis indicated a higher profit of Rs.903,018 at Pelwehera, Rs.602,091 at Dodangolla and Rs.935,576 at Gannoruwa with the optimum fertiliser treatment than any other treatment. T h e results of this study confirm that the systematic approach for site-specific fertilizer recommendation is an effective and reliable method to evaluate soil fertility status and nutrient limiting factors to recommend fertilizers and to refine the presently used recommendations for vegetable crops in Sri Lanka. A balanced fertilizer consisting of 200, 180, 400, 2 kg ha'1 o f N , P, K, Mo for Pelwehera, 200, 150, 400, 500, 160, 1, 5, 2 kg ha'1 of N , P, K, Ca, S, B, Mn, Mo for Dodangolla and , 200, 170, 180, 600, 1, I, 2 kg ha'1 N , P, K, Ca, B, Zn, Mo for Gannoruwa respectively, can be recommended for Cauliflower (Brassica oleracea L.) based on a systemic approach
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    A Critical edition and an annotated translation of the Dhatvatthavannana. vol I
    (University of Peradeniya, 2010) Indarathana, Rev. Muthukeliyawe
    The Thesis is based on the Dhatvatthavannana, the graphic description of pali etymology. principally; it is a critical edition with an annotated translation. This study is made in basically three parts such as introduction, edited text and its annotated translation. The introduction deals with general introduction to the Dhatvatthavannana, what is the root, the characteristic features of the Dhatvatthavannana, comment on the method of graphic description of Pali roots, the roots that were questionable and the utilized editing method. The edited text is made in seven chapters including one thousand eight hundred and nineteen roots with the addition of twenty three new roots. And the next part of the thesis is the graphic description of the Pali etymology. It also dealt with same seven chapters, which are an annotated translation of the edited text. Forth chapter is the conclusion of the entire thesis. Additionally there is an index of the roots.
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    a Genetic analysis of non-restorer lines in Sorghum (Sorghum Bicolor (L) Moench)
    (University of Peradeniya, 1983) Nath, Bhola
    A genetic analysis of malntainers of sterility in the milo-kafir cytoplasmic genetic system was undertaken at the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru, Andhra Pradesh, India during 1981-83, to study divergence, combining ability, heterosis and variance components of important characters through a 15xl5 dialle and lIne x tester cross analyses in sorghum . Results indicated high variabilIity in the non-restorer collection. Additive genetic varieance component was predominant In controlling important agronomic characters. Heritability estimates for all characters were high. High heteros is was observed for grain yield, panicle yield, biomass production, plant height and grain number. The expression of heteros is in yield was attributed to cumulative effects of yield components. Heteros is was not related to genetic, geographic or taxonomic diversity. All the high yielding crosses involved at least one parent with a high gca effect. Based on results, good prospect of Improving female parents for hybridization programme were envisaged, primarily due to the contribution of new variability from the population derived lines developed at ICRISAT. It was suggested to Initially screen parents on the basis of their perse performance and then evaluate their combining ability for optimal use of resources in a breeding program. A mass selection scheme subsequently followed by reciprocal recurrent selection for gca was recommended for the improvement of parental populations. A line, Rs/R-Z0768Z-5-1 recessive for the two genes (b1b1b2b2) determining. testa in sorghum grain, was discovered. The line would produce white grained sorghum hybrids with any poll inator parent and would be useful in breeding programmes on a global basis.
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    A Histological immunohistochemical and experimental study of obliterative arterial diseases of limbs. with special references to thromboangiitis obliterans
    (University of Peradeniya, 1986) Ratnatunga, N.V.I.
    Occlusive arterial disease of limbs, in the young patient is a common surgical problem in Kandy, Sri Lanka. The progressive ischaemia to the tissues of the limbs, often necessitates amputation, with resultant disability to the patient. A similar disease seen in other countries, is now designated as thromboangiitis obliterans or Buerger's disease after the original description of the disease, by the latter author in 1908. However the pathology seen in the patients from Kandy, Sri Lanka, with the clinical features referred to above has not been elucidated . The etiology of this obliterative vascular disease remains obscure. The present investigation was aimed at, 1. establishing the pathology seen in the blood vessels, of young patients with occlusive arterial disease, clinically resembling Buerger's disease 2. determining the etiology and pathogenesis of the pathological lesions observed. 3. designing an experimental model, to study the effects of tobacco on the vascular system by using the vessels of Tilapia mossambica fish, for this purpose. Amputated lower limbs and digits, and endarterectomy specimens were examined in this study. Histological, histochemical and immunohistochemical techniques were used for staining the tissue sections, made from this material. An experimental model was developed for investigation of effects of tobacco extracts, on the vascular system of the Tilapia mossarrbica fish. The results of this investigation show' that 1. a disease entity causing ischaemia to the lower limbs of young adult smokers, similar to that described by Buerger, (1908), exists in Sri Lanka. 2. in this condition focal disease of the intima is a possibility 3. deposition of either immune complexes containing IgG or antibodies to the vessel wall consisting of IgG, are present in the vasa vasorum of the arteries, and small blood vessels of the neurovascular bundle. 4. a vasculitis affecting small blood vessels of the thrombus, vasa vasorum of the artery, and small blood vessels of the nerve bundle, and connective tissues, had developed and that this appeared to be mediated by B lymphocytes and was possibly of immunological origin. The results of the experimental studies, indicate, that constituents of tobacco, possibly has the ability to sensitize mononuclear cells, in the Tilapia mossarrbica fish, and cause occlusion of small blood vessels in these animals. Future investigations should include serum studies of patients suffering from thromboangiitis obliterans, in order to detect antibodies to the arterial wall, and circulating immune complexes. The presence of complement in the arterial wall should also be looked for. The HLA pattern of affected individuals must be established. The patients should also be investigated for hypercoagulable states, of the blood. Investigations should also be carried out, in order to detect sensitization of lymphocytes, to tobacco and vascular antigens. Experimental studies to detect the effect of tobacco on the vascular system of mammals is a vista for future investigations.
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    A Lymphoscintigraphic study of the pattern of lymphatic flow in parients with lower limb lymphoedema in Kandy, Sri Lanka
    (University of Peradeniya, 2001) Udugama, J. M. Chandraguptha
    Increasing numbers of patients with unilateral or bilateral below or above knee lymphoedema with no apparent secondary cause have sought medical help in Kandy, Sri Lanka Radionuclide Lymphoscintigraphy has emerged in recent years as the Standard procedure for the visualization of the lymphatic system in patients with peripheral lymphoedema. Scintigraphic studies using radionuclides to examine the status of the lymphatic system of lower limbs in patients who suffer from lymphoedema in Sri Lanka using an available radiopharmaceutical have not been published. This study explains reasons for different levels of clinical lymphoedema found with each location of lymphoscintigraphic obstruction and compensatory mechanisms responsible for these differences based on lymphoscintigraphic findings. It also documents the prevalence and possible aetiology of lower limb lymphoedema if inthis group of patients. This study was done on eighty consecutive patients with lymphoedema of lower limbs with no apparent secondary cause, referred from Vascular Clinic of Teaching Hospital, Peradeniya. To asses the main compensatory mechanisms that control the _ extent of lymphoedema in these patients, the hypothesis of possible lymphovenous shunting was explored by studying the percentage and rate of liver uptake on scintigraphy. Lymphoscintigraphy was performed by injecting 148 MBq. of ”™Tc Sulfur Colloid according to a standard protocol using a Gamma camera with a dedicated computer system. Visual assessments of appearance of lymph vessels, nodes and tracer in the liver in each category over time intervals were carried out. The liver uptake percentages were recorded and quantified using a standard formula. To evaluate the compensatory mechanisms taking place to control the progression of lymphoedema at different levels of blocks, possible evidence for collateral flows and lymphovenous shunting was studied. Based on the demographic structure of this group of patients, it is apparent that lymphoedema in lower extremities were common in young females in 21 — 40 years age group with female dominance (F: M = 30:9) and a family predisposition. A female dominance was found in all levels of lymphoscintigraphic obstruction. These findings would strongly suggest the presence of primary lymphoedema in this group. Non visualization of lymphatics proximally but visualization of lymph nodes more distally suggests distal hypoplasia. Therefore I would suggest that the evidence of obstruction in the medial lymphatics in patients is due to primary lymphoedema in this group and may be an appearance caused by hypoplastic lymphatics or hypoplastic and fibrotic nodes often visualized in this group of lymph nodes. This hypoplastic and fibrotic nodal obstruction was considered the main cause for lymphatic obstruction. Other possibilities included stenosis of the lymphatics or lymph nodal channels consequent to perilymphangitis or lymphadenitis caused by secondary sepsis. It may be speculated in the clay soil, the aluminum and silica may play a role in the fibrotic process in this country as well and needs to be further studied. Percentage liver uptake in each of the clinical presentation of lymphoedema revealed a distinct pattern. Patients with unilateral below knee lymphoedema with popliteal nodal block, blocks in the lymphatics on the medial, side of the knee and lower vertical set of inguinal nodes showed a different pattern. These groups had significantly higher liver uptake values than even the control groups (p = 0.001, 0.0002 and 0.0001), suggestive of lymphovenous or lymphnodovenous shunting. This could possibly account for the lower level of clinical lymphoedema in those with blocks in the inguinal nodes. Since the collateral flow was observed, this would suggest the presence of collateral circulation to minimize the extent of lymphoedema. The fact that increased liver uptake were seen in patients with unilateral lymphoedema presenting with lymphatic blocks in the popliteal, medial side of the knee and lower vertical set of the inguinal nodes when compared to control normal limbs clearly suggest early diversion of tracer through into the systemic circulation. This is a strong argument to suggest the presence of lymphovenous shunts or lymphnodovenous shunts. It also suggests that such shunting may be responsible for the varying levels of lymphoedema in these patients.
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    A Novel approach to the control of aedes aegypti, a vector of dengue fever and pollution abatement by the use of porphyrin derivatives
    (University of Peradeniya, 2005) Herath, H. M. A. M. C.
    The discharge of hazardous chemicals by the activities of mankind has been a serious threat to the environment. Among the pollutants, pesticides, coloured dyes and heavy metals are significant in terms of their detrimental consequences to living organisms. Therefore, the development of efficient and reliable techniques for the removal of these pollutants from the environment is essential. In the pollution abatement studies, it was demonstrated that porphyrin derivatives such as haematoporphytin dihydrochloride (HPDHC) and protoporphyrin dimethylester (PPDME), in the presence of visible light and oxygen, could be utilized for the destruction of coloured organic dyes in aqueous media. The visible light irradiation of oxygenated aqueous solutions of coloured dyes magenta (MaG), crystal violet (CrV) and hematoxylin in the presence of HPDHC or PPDME showed complete colour bleaching after 12 hours. The rate of photobleaching was found to be sensitive to the medium pH. At low pH (pH = 3.2), a higher oxidative degradation rate for MaG was observed in comparison to the low rate at pH 6.0. Analysis of photoproducts of MaG and CrV in acidic as well as basic media showed the formation of micromolar levels of NO₃⁻ ions resulting from the destruction of amine moieties of the dyes. Photebleaching experiments were carried out in the presence of different quenchers such as 1,4-diazabicyclo[2.2.2]octane (DABCO) for singlet oxygen and 1,4- benzoquinone (BQ) for the superoxide anion O₂°⁻. Only BQ was able to stop photobleaching suggesting that the photooxidation of these dyes are mainly caused by O₂°⁻ , which is generated by an electron transfer from the excited sensitizer to ground state oxygen in the photosensitization process. The participation of singlet oxygen in dye destruction process is comparatively low. Solubility of porphyrins in water is an essential requirement when they are used in aqueous medium. Water soluble cationic porphyrin derivatives 5,10,15,20-tetrakis(4-N- pentyl- pyridyl) porphyrin, [(TPePyP)H)₂]⁴⁺, and its zinc analogue [(TPePyP)Zn¹¹]⁴⁺ were synthesized by introducing cationic pyridyl groups into the meso positions of the porphyrin core. Photobleaching studies carried out in aqueous solutions of varying pH show that, in the presence of oxygen, [(TPePyP)H)₂]⁴⁺ undergoes fast photodegradation when the solution is irradiated with 560 nm light. The steady-state singlet oxygen quantum yields (ɸ) measured in DMF for [(TPePyP)H)₂]⁴⁺ and it’s Zn analogue were 0.80 and 0.85, respectively. These values are in the same order of magnitude as those of well-known porphyrins such as HPDHC and PPDME. The aggressive and destructive nature of O₂°⁻ towards most of the organic materials is an important advantage in pollution abatement. A method generally employed to indirectly test for O₂°⁻ is the study of a O₂°⁻ driven reaction in the presence of a scavenger like superoxide dismutase or benzoquione. It was found that O₂°⁻ , was effectively quenched when 1,2,3-triketohydrindene hydrate (NHy) was added to an oxygen-saturated solution, where O₂°⁻ is electrochemically generated at a glassy carbon electrode by applying a potential of -0.75 V vs Ag/ApCI wire. The suppression of the oxidation peak of O₂°⁻ with the addition of NHy in cyclic voltammetry was in close agreement with the results obtained in rotating ring disk voltammetric experiments. It was revealed that the decolouration of MaG by the O₂°⁻ produced by HPDHC in the presence of light in DMF was retarded in the presence of NHy. The syntheses of porphyrin dyads in the combination of free-base and Zn porphyrin units with different redox potentials was attempted. In this respect, several porphyrin derivatives, meso-5-(4-hydroxyphenyl)-10,15,20-trisphenyl porphyrin (HPTrPP), meso-5- (4-hydroxyphenyl)-10,15,20- tris(4-methoxy phenyl)porphyrin (HPTrMPP), meso-5-(4- hydroxyphenyl)-10,15,20-tris(4-sulfonatophenylammonium porphyrin [NH₄]₄[HPTrSPP] and their Zn derivatives were synthesized and characterized by UV-Visible , 'H NMR spectroscopy and cyclic voltammetry. The porphyrin-sensitized photoinactivation of the 2ⁿᵈ and late 3ʳᵈ instar larvae of the urban dengue mosquito Ae. aegypti was investigated as a novel approach in controlling the mosquitoes. In this study it was revealed that haematoporphyrin dimethylester (HPDME), HPDHC, PPDME and haematoporphyrin (HP) caused a high level of phototoxicity to the 2ⁿᵈ and late 3ʳᵈ instar larvae of Ae. aegypti in Pyrex and clear plastic containers. In contrast, the mortality under natural conditions was less in coconut shells, tin caps and PVC gutters. Least larvicidal activity was observed in tires. These results suggest that the efficacy of mortality depends on the amount of light reaching the photosensitizer (this is maximum only in case of Pyrex glass and clear plastic containers), the nature of the surface of the container, the concentration of the sensitizer and unit volume per larvae. Out of four sensitizers tested, a high level of larvicidal activity was observed with aqueous solutions of HP which showed the highest phototoxic effect at 2.5 ppm in laboratory experiments. Field experiments set up inside and outside houses also showed that a high larvicidal activity with HP (160% mortality in four days) in the presence of light (outside). Conversely, the mortality was less inside the houses (36.79 %). The Phototoxic studies extended using HP and HPDHC towards other fresh water fauna, mayfly larvae, Poecilia reticulata (guppy) and Bufo melanostictus (tadpole) did not show any apparent toxic effect even after seven days at 100 ppm. This concentration is 40 times higher than that used in bringing about the effective killing of Ae. aegypti larvae. Based on field experiments as well as toxicity studies, both HP and HPDHC could be used effectively and safely to hasten the larval killing process, thus controlling the adult mosquito population.
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    A Political economy perspective on South Asian regionalism
    (University of Peradeniya, 2008-08) Perera, Welgamage Lalith Prasanna
    The study provides a comprehensive analysis of South Asian regionalism. Although economic integration holds many benefits for developing states, in South Asia regional integration is still at an early stage. By examining the main propositions of several theories: orthodox theory, new regionalism and theories on the political economy of regionalism, the study addresses the question of whether the South Asian countries benefit adequately from a regional integration under the SAARC framework. Many of the recent studies on South Asia attempt to capture the effects of regionalism by applying quantitative methods, utilizing exceedingly limited frameworks. The present study juxtaposes formal and informal economic, political and social aspects, presenting a multi-dimensional approach to South Asian regionalism. Hence, the study offers a political economic perspective, which is critical to the growth of existing views on regionalism and its effects on South Asian economies, Both quantitative and qualitative analyses are used to examine primary and secondary data related to economic, political and social aspects of the study. An investigation en present strategies of South Asian economic relations is conducted by evaluating the South Asian Preferential Trading Agreement (SAPTA) and South Asia Free Trade Agreement (SAFTA). The study calculates indexes such as Export and Import Intensity Indexes, Anti-Regional Trade Bias Index and Trade Balance Index using formal data. The research also tests some of the common characteristics of successful regional arrangements. Next, a time series regression model is used to test whether there is a significant impact of regional integration on intra-regional trade flows for three member countries in the region: India, Pakistan and Sri Lanka. The study also employs a commodity group analysis to recognize the South Asian intra regional dommaadily trade under 6 digit level of Harmonized System classification. A primary survey to understand the nature of informal trade and its characteristics in Sri Lanka was also conducted. Data on political and social dimensions such as issues of security and conflict for the region were extensively examined. In general, the data is framed within a literature review on existing academic material on regionalism, South Asian regionalism, political economy and other related topics. The study finds that the SAPTA/SAFTA initiatives have had impact on trade patterns in the region, with more benefits to the larger economies. India is considered to be the net-exporter to the region. This asymmetry is reflected in the Anti-regional Biased index as well, revealing that India and Pakistan are more outside.biased in international trade. Interestingly, the regression analysis proved that with the implementation of SAPTA and SAFTA, intra-regional trade flows of member countries with partner countries have increased. This implies that regional trading arrangements have positively contributed to stimulate intra-regional trade. The top 20-commodity analysis found that the SAARC region should focus on agricultural and manufacturing commodities. The findings further suggest that Sri Lanka would benefit from promoting tea, rubber, coconut, diamonds and gems within the region. Importantly, the study found that when informal trade in the region is taken into consideration intra-regional trade among the SAARC members is much higher than the recorded official trade. One reason for higher informal trade may be higher regional trade impediments. The case study survey undertaken in the study demonstrates the extensive level of informal trade between Sri Lanka and India. The research also finds that due to the slow advancement and other impediment to regionalism, member countries have opted for bilateral relations. When comparing with other regional blocs the rapid movement to free trade agreements is a weakness in the existing regional integration framework. The prevalence of various levels of conflict is identified by the study as a serious hindrance to the regionalism in South Asia. Regional cooperation may also be necessary for resolving those conflicts. Economic regionalism cannot be sustained without political dialogue and support among group members. In conclusion, it should be noted that although the study focuses on the South Asian regional framework, much of the findings of the study have wider application in regionalism in relation to developing countries across the globe. This detailed study of economic integration under the SAARC framework with political economic perspective, is a timely need for policy and decision- making in the region. This study exposes economic, political and social aspects, presenting a much needed multi-dimensional approach to South Asian regionalism.
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    A Preliminary analytical study of the historical archeology of inscriptions located in the middle and upper valleys of Deduru Oya system: B.C.3 century to 3 century A.D.
    (University of Peradeniya, 1997) Senanayake, A.M. Piyathissa
    The Primary source material in this study are found in the early and later Brahmi inscriptions, that have a chronological context extending from 3rd Century B.C. to 3rd Century A.D.. In addition, the internal evidence from archaeological and literary source have been utilized as substantiating evidence in this study. The scientific basis of historical conjectures have been further strengthened with the induction of geological and other environmental data into this study. Similarly, various other ficlds in the social science and the humanities have been utilized for a better understanding of the above mentioned sources. This study therefore is carried out from a multi and interdisciplinary perspective. The primary objective of this study is to have an understanding of early socio - economic formations in the Deduru Oya system. For this purpose the distribution pattern of the Brahmi inscriptions was undertaken as the primary study. The pattern of distribution and its multi faceted features have been evaluated in terms of quality, quantity and in the context of vertical and horizontal dynamics. Several micro studies were carried out on the locational features of natural resources and techno - cultural communities. On this basis it was possible to hypothesise the production - distribution and the route network inter linking the montane region with the plains. This study has a focus on specific ecological zones within the Deduru Oya system. This indicated that socio - economic forces associated with communities in the upper valley system progressed at a relatively rapid pace over those in the middle valley. During the pre Christian period, socio - economic units under the leadership of pre state lineage chieftains had evolved at several locations in the Upper valley. However, by the Ist and 2nd centuries A.D., these units show institutional formations influenced by the state system. The latter represented the logical conclusion of early historic institutional formations in the upper valley system. This also represents a period when there was a synthesis of early micro - eco zones into lager unites and finally leading to the emergence of intermediary transitional productions distribution ecological zones
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    A Re-assessment of the bacteriological clinical and immunological features of typhoid in Sri Lanka
    (University of Peradeniya, 1981) Thevanesam, V.
    Typhoid fever, caused by Salmonella typhi, is endemic in many parts of the technologically underdeveloped world including Sri Lanka; it results in high morbidity with a mortality of 2 - 3per cent. The diagnosis of typhoid depends on the recognition of its clinical features, serological tests and definitively, on the isolation of Salmonella typhi from body fluids or tissues. A change in the clinical presentation of typhoid has recently been reported. This study of the clinical features in patients with bacteriologically proven typhoid showed that a mild febrile illness with headache, intestinal symptoms (especially diarrhoea)occurred frequently. Rigors were not uncommon and should therefore not exclude a diagnosis of typhoid. Hepatosplenomegaly were the only physical signs which were detected with any constancy. Unusual presentations were not seen in our patients. The clinical picture of typhoid was however not sufficiently distinctive to permit of a definite clinical diagnosis. Complications were uncommon. Isolation of Salmonella typhi from patients' blood by both clot and whole blood culture gave comparable results. Isolation rates from blood and faeces in patients with a tentative diagnosis of typhoid (on clinical features and serological reactions) were low. Strains isolated from our cases confirmed with the typical morphological, cultural, biochemical and antigenic properties described for the species. Fifty percent of the Vi + strains were of phage type E1 with approximately 25per cent of Vi or with degraded Vi, suggesting that phage typing would not be of much value in epidemiological studies. All the strains were sensitive to chlora~ph8nicol by the disc diffusion method, with MIC values in the tube dilution tests ranging from 2.5 to 10ug/ ml,(values reported from other studies lie between 0.75 5ug/ml). The serological diagnosis of typhoid is useful in the diagnosis of typhoid fever particularly in countries with inadequate facilities for the isolation of Salmonella tvphi. A study of the '0' and 'H' antibody titres in patients with bacteriologically proven typhoid and in control subjects (healthy volunteers and patients with non-typhoidal illnesses) showed that antibo dy titres are significantly higher in patients with typhoid. '0' antibody titres of over 1:240 could be used with 92per cent confidence as a diagnostic criterion of typhoid if either blood culture is either not available or negative. The 'H' antibody titres were less helpful, false negative results having been obtained in approximately 30i.0f patients. Basal antibody titres were found to vary considerably between the healthy volunteers, normal blood donors and conservancy labourers although these subjects were from the same geographical area. A study of the Cell Mediated Immune Response (CMIR) to Salmonella tvphi antigens in patients with typhoid fever was done using the leucocyte migration inhibition test and a crude extract of antigens from Salmonella tvphi. An antityphoid CMIR developed a significant number of patients with bacteriologically proven typhoid fever. The duration of the clinical illness and occurrence of complications could not be correlated with the development or absence of a CMIR. There was also no correlation between the '0', 'H' and 'Vi' agglutinin titres and the development of an antityphoid CMIR in the typhoid patients. Two groups of control subjects (healthy volunteers from the general population and conservancy labourers) were also studied concurrently with the patients for their humoral and Cell Mediated Immune Response to Salmonella tvphi. Patients with typhoid had a significantly higher incidence of an antityphoid CMIR than healthy volunteers but no difference was found between the positivity rate in patients and in conservancy labourers, probably on account of the latter's occupational exposure to human faeces which may have contained Salmonella tvphi. The Humoral Immune Response (HIR) and CMIR were also studied in two groups of normal volunteers (members of the general public and conservancy labourers who had no previous history of typhoid or antityphoid vaccination), before and after subcutaneous (SO) and intradermal (ID) immunisation with heat killed - tricresol preserved TAB vaccine to determine the efficiency of the vaccine in inducing an antityphoid CMIR. In the first study, a significant antityphoid CMIR was demonstrable in both se and ID vaccinated subjects though here was no significant difference between the two groups. The liability of the CMIR inducing antigen(s) was suggested by the reduction of the rate of CMIR induction with ageing of the vaccine. In the second study done with a fresh vaccine over a shorter period of time, the development of a significant antityphoid eMIR was confirmed. Post immunisation energy in the Cell Mediated I~~une Response was seen after both SC and ID immunisation, in both studies and may partly explain the development of provocation typhoid.
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    a Site specific fertilizer recommendation for Rice (oryza Sativa L.) using a systematic approach to soil fertility evaluation
    (University of Peradeniya, 2006) Bandara, W. M. J.
    Rice (Oryza saliva L.) is one of the oldest crops cultivated and the staple food in Sri Lanka. To feed the nation in future, the present average yield has to be increased up to 4.5 t ha~! even though it is presently stagnated at 4.0 t ha"1 . Therefore, the main objectives of this study were to identify soil fertility limiting factors in three rice growing soil series in the Low Country Intermediate and Dry zones of Sri Lanka using a systematic approach combining soil analysis, fixation studies and greenhouse nutrient survey and to formulate a fertilizer recommendation for the three soils and finally to test the validity of these recommendations by conducting field experiments at the respective sites. Three rice growing soil series viz Galwewa soil series (Alfisols) at Aralaganwila, Agricultural Research and Development Centre, Elayapattuwa soil series (alfisols) at MahaIlluppalama, Seed Farm in Low Country Dry Zone and Kurunegala soil series (Ultisols) at Batalagoda, Rice Research and Development Institute in Low Country Intermediate Zone were used. Representative composite soil samples (0-20 cm) were analyzed for physical and chemical properties under dry conditions as well as submerged conditions using standard methods. Both under dry and submerged conditions, available nutrient status was determined by a three step extraction method; extraction with ASI solution (0.25 M NaHC03 + 0.01 M /EDTA+0.01 M NH4F ) for P, K, Cu, Fe, Mn and Zn, 1 M KCI extraction for NH4 -N, Ca, Mg, Na and active acidity and 0.08 M CaH2 ( H2P04 ) 2 . H20 extraction for B and S. A fixation study was conducted to identify the fixation capacity of these soils for P, K, Cu, Zn, Fe, Mn, S and B under both dry and submerged conditions. The amount of fertilizer to be supplemented was calculated based on the initial nutrient values and, when deficient, the rates of P, K, Cu, Zn, Fe, Mn, S and B were adjusted based on the fixation capacity. The optimum fertilizer recommendations formulated based on dry and submerged soils were tested in the greenhouse using a modified missing element technique. These recommendations were tested in Fields where soils were sampled using rice (variety Bg 352) for two seasons; Yala followed by Maha. The routine soil analysis showed deficient levels of N, P, K, S, Mg, B, Cu, Mn and Zn in Galwewa soils under dry soil analysis basis while Mn was sufficient when soil was analyzed after submergence. Nitrogen, P, K, Mg, S and Zn were deficient in Elayapattuwa and Kurunegala soil series under both dry and submerge conditions. However, availability of N, P, K, Fe and Mn was increased while S, Zn and Cu were decreased with the submergence of soils. The greenhouse nutrient survey confirmed the deficiencies of nutrients identified through soil analysis. Responses to nutrients were clearly indicated, with significantly low dry mater yields (p<0.05) in most treatments that provided one nutrient at a deficient level, as compared to the optimum, which provided all nutrients at adequate levels. Nutrients formulated under dry soil analysis gave high biomass yield than that formulated under submerged soil analysis in both Galwewa and Kurunegala soil series but in Elayapattuwa series it was vice versa. The results of the greenhouse studies therefore, indicate that analysis of air-dry soils is equally effective or even better than analysis under submerged conditions to predict deficiencies, toxicities and other nutrient problems for rice grown on submerged soils. Considering the grain yields obtained in different fertilizer treatments, following fertilizer recommendations could be suggested for the three soils: 175 kg N, 40 kg P, 100 kg K, 40 kg S, 25 kg Mg, 0.5 kg B, 0.5 kg Cu, 2 kg Zn and 2 Kg Mn for Galwewa series, 175 kg N, 65 kg P, 60 kg K, 50 kg S, 25 kg Mg and 2 kg Zn for Elayapattuwa series, and 160 kg N, 60 kg P, 120 kg K, 25 kg S, 30 kg Mg and 2 kg Zn rates for Kurunegala soil series. Cost benefit analysis clearly indicated that the suggested recommendations for the three soil series were more economical. Therefore, providing nutrients to the soil based on systematic approach was beneficial in terms of rice yield and profit.
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    A study of deviance in context of Sri Lankan schools from an interactionist perspective
    (University of Peradeniya, 2005) Attanayake, R. P.
    Deviance is a phenomenon that occurs mostly at secondary school level, when students are in their adolescence. Studies have indicated a relationship between perceived negative social reactions towards leading to negative self — concepts and their deviant behaviour. Thus labelling theory argues that school authorities use rules to access students and staff and that the individuals who do not abide by these rules or conform to expected norms are labelled as deviant. Accordingly, deviance is not an inherent characteristic of an individual but rather a response to the social reaction towards an individual's behaviour. Even though a large number of studies on deviance have been conducted in the developed world, very few such studies have been carried out in Sri Lanka on deviance. Deviance in context of Sri Lankan schools from an interactonist perspective is an attempt to use an appropriate methodology for the study of deviance. The sample for the study comprises students of seventh and eleventh grades and their teachers in two selected schools in the Central Province. The research methodology used is the ethnographic method, which is effective in identifying the incidence and causes of deviance among these students. Participant observation and informal discussions are thus used for data collection. The study identifies several issues related to deviance in schools and also the factors contributing to deviance. These factors are the attitude of these teachers, attention given to methods practiced by school authorities in monitoring student behaviour., social background of students, the school environment and the community in which the school is located. The study also finds that while certain student groups in the school community are seen as law - abiding others are seen as law— braking. At times, social misbehaviour extended to drug addiction, smuggling, watching of pornographic films and CD's by a limited number of students. The most serious problem identifies is sexual misbehaviour among a few students. The study makes several remedial measures that can be taken to reduce deviance in schools and suggests area for further research A student-based problem solving process is a need to identify and sort out certain students as being deviants and for reducing deviance in schools. The most frequent explanation of deviance in schools is seems to be that the students referred to diverge from norm from normal, expected behaviour. An important question concerning this phenomenon is of course how the school defines normal and deviance respectively. The rules and regulations governing the school must be presented io all parties concerned and interested in the welfare of the school in such a clear — out manner to give definite and exact meanings, so that no misinterpretations can be made. Society including educational administrators school counselors, school authorities, teachers and parents should participate in this so called process. In order to meet new approaches e.g. the fruitfulness of applying modified labelling theory to deviance in schools, doing quantitative research on deviance in schools deviance in girl’s schools and boys schools separately, further studies seems necessary.
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    A Study of early buddhist meditation: a comaparative study based on the pali nikayasa and Chinese agamas
    (University of Peradeniya, 2005) Herng, Toong
    This dissertation attempts an examination of forms of meditation prevalent during the time of the Buddha and the newly discovered forms of meditation in Buddhism resulting in immediate attainment of nibbana here and now. Modern scholarship shows a difference in the understanding of the meditations that were known in the Buddhist tradition, the Theravada tradition in particular. Some maintain that the meditations are of wholly Buddhist origin; others who are opposed to that view maintain that they were borrowed from Brahmanism; some suggest that they were a combination of the Buddhist and the non-Buddhist methods. Some even radically deny the function of meditation in the path of liberation by contending that the merit of insight alone is sufficient for the attainment of final liberation. The present study seeks to show that some of the meditations were re-examined by the Buddha and some others were originally taught by the Buddha. These meditations, either re-evaluated or newly discovered were meant to lead the adept effectively to the attainment of final liberation. The inquiry of this dissertation has been mostly limited to the Pali Nikayas and the Chinese Agamas considering that these canonical traditions, for the most part, preserve authentic sayings of the Buddha connected with the topic under investigation. I demonstrate in three fundamental ways the contribution of Gotama Buddha towards the enduring achievement of ending suffering by means of meditation. First, I have examined the attitude of the Buddha towards the then known nine samapattis thereby showing the attainment of nibbana can be achieved by using any of the nine samapattis as a base. Second, I have examined the threefold samadhi as methods of overcoming the limitations of the methods of meditation of the ascetics and as leading to the attainment of nibbana giving the opportunity for a person to abide in nibbanic life. Third, I have shown that andapanasati is a practice leading anyone to nibbana regardless of whether he had experienced any form of meditation.
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    A study of internal browning of two cultivars of pineapple with special reference to heat shock treatment as a control measure
    (University of Peradeniya, 2002) Weerahewa, Hewa Lunuwilage Darshani
    Internal browning, commonly encountered in pineapple during prolonged cold storage, is a major obstacle to long distance export of fruit under sea freight. In the present study, the internal browning of fruit of two pineapple cultivars was investigated with the view of establishing suitable postharvest physical treatments that induce tolerance to the disorder. Three-week storage trials were conducted simulating the sea freight export conditions at 10°C and 85% RH. In Mauritius, the internal browning symptoms appeared within a week of storage at 10°C initially in the marginal core tissue which subsequently spread to the surrounding flesh. But in Kew, the symptoms commenced only after 2-3 weeks of storage as isolated patches in the tissue surrounding the core. There was a clear difference in the time of incidence and pattern of symptom development between the two cultivars. The cv. Mauritius showed comparatively faster ripening and respiratory rates and greater accumulation of acids during cold storage, than the cv, Kew. In both cultivars the tissues undergoing browning displayed greater PPO, peroxidase activity and electrolyte leakage. Harvesting fruit early at 100% green stage reduced the incidence and severity of internal browning in both cultivars. Several postharvest physical treatments were tried out to induce cold tolerance of fruit. Heat shock treatment in the form of hot water dip immediately after harvest was found to induce fruit tolerance to internal browning in both cultivars and the best temperature-time combination was 38°C for 60 minutes. The treated fruit developed 75% and 50% lesser browning in the flesh and core region respectively. The overall reduction of internal browning was about 55-60%. The results obtained from different temperature-time combinations suggested that an internal tissue temperature of 36-38°C is a prerequisite for induction of fruit tolerance. Although heat treatment significantly reduced internal browning, it slowed down fruit ripening and associated changes and increased water loss compared to untreated controls. However, provision of modified atmosphere conditions to heat-treated fruit during cold storage enhanced cold tolerance by another 10% and resulted in lesser water loss, hence better appearance. The mechanism of induction of fruit tolerance following heat treatment appeared to be through production of heat shock proteins. It is possible that the cellular repair mechanisms following cold injury may be taking place more rapidly in treated fruit. A cold shock at 4°C for 60 minutes, preceded or followed by heat treatment, also - effectively reduced the internal browning of cv. Mauritius. Here the treated fruit remained firmer and showed lesser cell damage than the fruit provided with heat shock treatment alone or heat shock followed by MA. Intermittent warming of fruit during the cold storage regime also reduced internal browning cv, Mauriti
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    A study of prosody & rhetorics of pali poetry
    (University of Peradeniya, 1997) Jayasena, K.L.A.D.
    Abstract is attached
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    A study of some aspects of the micobacterioses in Ceylon
    (University of Peradeniya, 1974) Pinto, D.D.M.R.M.
    In this work an attempt has been made to study some aspects ot the "Mycobacterioses" in Ceylon. The mycobacterioses are infections Produced by the genus Mycobacterium. Mycobacterioses are seen allover the world and many aspects ot these are as yet not investigated or are poorly investigated. These infections pose (special problems in the tropical and developing countries, but the information on these from the latter countries is scarce. The literature on any aspect of the mycobacterial infections in Ceylon is very scanty. The mycobacterioses like any other infections may be examined from two main points ot View: 1.The reaction of the host to the parasite, and 2. The parasite. The reaction of the host to the parasite is embodied in the host's immunological responses to the parasite. These immunological responses may be of the cell mediated component and the humoral component. In this study the cell mediated response has been investigated using the differential (or comparative) tuberculin test, and the humoral response, using Takahashi's antitubercle phosphatide kaolin agglutination test for antiphosphatide antibodies. The differential tuberculin test was done on several population groups in Ceylon, viz. a) Persons of the general. population from rural areas who were not BCG vaccinated, b) Tuberculosis patients, c) BCG vaccinated persons in the general population, and d) Leprosy patients. The test was carried out in all groups using six different PPD antigens derived from Myco. tuberculosis (PPD-S), kansasii (PPD-Y, Runyon's Group I), Myco. scrofulaceum (PPD,Runyon's Group II), Myco. avium (PPD-A) and Myco. batteyii (PPD-B, both of Runyon's Group III) and Myco. fortuitum (PPD-F, Runyon's Group IV). The test technique used was the WHO Standard Tuberculin Test (Mantoux Test), each subject usually being given four PPD antigens. The investigation in the unvaccinated general. population showed that nontuberculous mycobacterial sensitisation and hence infection, was very common in Ceylon, and more common than tuberculous sensitisation. Marked differences in the degree and incidence of nontuberculous sensitisation were found to occur with altitude (the population investigated being at 3 different altitudes, 6,500 feet, 1,500 feet and at sea level), being lowest at high altitude and highest at sea level. No differences in pattern of sensitisation appeared to occur with increase of age (those tested being 12 years of age and above) and in the different sexes, at sea level and at mid altitude, but appeared to occur at the highest altitude. It was seen that at an elevation of 6,500 feet the incidence and degree of mycobacterial sensitisation appeared to increase with age and was greater in males than in females. Differences in pattern of sensitisation were also observed between Sinhalese and Tamils at midaltitude. It was suggested that differences in occupation was probably the cause of the higher degree and incidence of sensitisation seen in Sinhalese, viz. paddy cultivation by the latter. Evidence was produced from the veterinary field, from studies in cattle and buffaloes, in Kenya and Ceylon to support this finding. It was found that sensitisation among the Ceylonese populations tested was commonest to PPDs derived from Runyon's Group II and III organisms and least with Group I and IV organisms. The tuberculosis patients investigated were mostly from mid altitude areas similar to that described for. the general population. It was found that there were both similarities and differences in the distributions of reactions to nontuberculous PPDs between the tuberculosis patients and the general population, from the mid altitude area studied. The possible causes for these are discussed. With PPD-S, the pattern of distribution seen in tuberculosis patients is markedly different from that of the general population group, but similar to that found in tuberculosis patients elsewhere in the world. No differences were found in the distributions of tuberculosis patients of different ages, sexes and of different races. Examination of the pattern of reactions to the different antigens shown by tuberculosis patients showed that clearly larger (dominant) reactions to PPD from Myco.tuberculosis was seen only in 60 percent of pateints.Thus it was concluded that the differential test did not always identifythe mycobacterial infection in tuberculosis patients. Comparison of.............
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    A Study of the uterotonic and anti-implantation activities of some selected plant extracts and products
    (University of Peradeniya, 1991) Goonasekara, M.M.
    Sixty one plants reputed to have anti-fertility activity were tested on female Sprague-Dawley rats, in order to isolate active compounds with a potential for use in human fertility regulation. The experiments were carried out with crude plant extracts in the first instance. If any activity was present, the extracts were fractionated. Two bioassay methods were utilized in these investigations. The extracts were assessed for Possible abortifacient effects by an in vitro method of testing for uterotonic activity. In this method the isotonic contractions of the isolated uterine horn of the oestrogenised rat were observed in the presence of various plant extracts. A total of forty two extracts, one fraction and two pure compounds were tested in the in vitro system and thirty extracts gave Positive results. An in vivo method was utilized in order to determine any anti- implantation, early abortifacient and/or foetal resorption effects of these extracts. One hundred and thirty extracts as well as one hundred fractions and seven pure compounds were tested by the in vivo method. The rats were administered the extracts from day 1-10post- coitally and the anti- fertility effect was assessed on the sixteenth day at autopsy. Five plants, namely, calotropis gigantea calotropis procera, plumeria rubra, Juniperus sabina and Jatropha curcas were identified as highly promising leads from which anti-fertility compounds may be isolated. Since several plant extracts resulted in a loss of appetite ,the effect of a reduced feed intake on reproduction in laboratory animals was also investigated. The tests demonstrated the need to monitor the feed intake when using laboratory animals for anti fertility tests
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    A study of the uterotonic and anti-implantation activities of some selected plant extracts and products
    (University of Peradeniya, 1991-01) Gunasekare, Manel Mawalagedera
    Sixty one plants reputed to have anti-fertility activity were tested on female Sprague-Dawley rats, in order to isclate active compounds with a potential for use in human fertility regulation. The experiments were carried out with crude plant extracts in the first instance. If any activity was present, the extracts were fractionated. Two bioassay methods were utilized in these investigations. The extracts were assessed for. possible abortifacient effects by an ir vitre method of testing for uterctonic activity. In +this method the isotonic contractions of the isolated uterine horn of the oestrogenised rat were observed in the presence of various plant extracts. A total of fogty two extracts, one fraction and two pure compounds were tested in the in system and thirty extracts gave positive results. An ir vive method was utilized in order to determine any anti-implantation, early abortifacient and/or foetal resorption effects of these extracts. One hundred and thirty extracts as well as one hundred fractions and seven pure compounds were tested by the im vive method. The rats were administered the extracts from day 1-10 post-coitally and the anti-fertility effect was assessed on the sixteenth day at autopsy. Five plants, namely, Calotreopis gigantea, Calotropis precera, #Flumeria rubra, Juniperus sabina and Jatropha curcas were identified as highly promising leads from which anti-fertility compounds may be isolated. Since several plant extracts resulted in a loss of appetite, the effect of a reduced feed intake on reproduction in laboratory animals was also investigated. The tests demonstrated the need to monitor the feed intake when using laboratory animals for anti-fertility tests.