PURSE 1996

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A Survey of Aphids and their Natural Enemies on Economic and other Plants
(University of Peradeniya, Peradeniya, 1996-08-10) Wjeratne, M. A. P.; Edirisinghe, J. P.
Aphids (Homoptera: Aphididae) are a group of insects that live on plants and feed on the plant sap. Thereby, they are able to transmit viral diseases in plants. Over 4000 species of aphids are known to be present in the world, of which 300 species are potential viral vectors. From neighbouring India, about 1000 species of aphids have been recorded and half of them are endemic to that country. About 72 species of aphids had been reported from Sri Lanka prior to this study and these had been collected either from a few economic crops or insect traps. The objectives of this study were to carry out a swvey to identifY the aphid species that are present in the country, record the host plants of these aphids and to identify the natural enemies of the aphid. The swvey was carried out in 25 selected areas that came under 6 agro-ecological regions of the country. In each area at several sites, the natural vegetation and the cultivated plants were closely examined for colonies of aphids. A few aphids were collected into 70% alcohol and were later slide mounted and identified. Aphid colonies were further examined for parasitized aphids and insects predatory on aphids. The plants on which aphids were present were examined for probable signs of viral infection. Over 1000 plant species were examined during the study and aphid were present only in 300 plant species belonging to 72 plant families. A total of 48 species of aphids in 28 genera were collected and identified. Aphid infested plants included vegetable and other food crops; weeds, grasses and non grass weeds, ornamental plants, medicinal plants and forest trees. Amongst them were 15 species of endemic plants. Vegetables and non-grass weeds harboured the largest number of aphid species. Among the aphids collected were 21 aphid species in 8 genera that had not been recorded from Sri Lanka previously. Among them were three rare species of aphids. Majority of the aphids collected were present on several species of plants (polyphagous), while about 15 aphid species were restricted to one or two plant species. Two of the 7 endemic species of aphids recorded for Sri Lanka were also collected during the survey. Among the aphids collected were 27 species of aphids that are well known potential viral vectors. Yet, only 40 species of plants infested by 12 species of aphids showed probable signs of viral infection. Natural enemies of aphids collected consisted of 21 species of predators (F Coccinellidae, Chrysomelidae, Syrphidae and Chrysopidae) and 4 species of parasitoids (F. Braconidae). These natural enemies were mostly associated with aphids on vegetables and non-grass weeds.
A. Preliminary Study on Worm Burden in the Gastrointestinal Tract of Goats and Its Association with the Packed Cell Volume Hemoglobin concentration, Total Protein and Eggs Per Gram of Faeces
(University of Peradeniya, Peradeniya, 1996-08-10) Hewawickrama, A. K. B.; Rajapakse, R. P. V. J.; Horadagoda, N. U.
Parasitic gastro-enteritis has been recognized as one of the major constraints to the development of the goat industry in Sri Lanka. Although some of the parasites responsible for the disease have been identified, the purpose of this study was to quantify relative numbers of each species in order to determine their significance in the usefulness of eggs per gram (EPG) of faeces and packed cell volume (PCV) and haemoglobin (Hb) percentage in the blood as indicators of the worm burden particularly blood sucking nematodes. Young goats (age-<18 months) brought mainly from dry zone to the Colombo municipal abattoir between January to July of 1996 were selected for this Study. Samples of blood were collected into EDT A for the estimation of PCV and Hb% and faeces were obtained directly from the rectum for determination of EPG. The gastrointestinal tracts were collected at the time of slaughter and the parasites in the contents of the abomasum, small and large intestines were identified and counted separately. The abomasum and small intestines were subjected to pepsin digestion in order to determine the presence of histrophic larvae. Nine species of helminths were identified in 124 of the 125 animals examined. One animal was parasite free. The nematodes present included Trichostrongylus colubriformis (78.72%), Oesophagostomum columbianum and Venulosum (89.36%), Haemonchus contortus (65.0%), Strongyloides papillosus (5.21%) Trichostrongylus axei (40.0%), Trichuris ovis (50.0%) and Bunostomum phlebotomum (2%). Moniezia benedine, a cestode was revealed in eleven animals (11.7%). The pepsin digested contents of the abomasum revealed larvae only in 11 animals (11.7%) and small intestines did not reveal any larvae. There was no association between the EPG, PCV and Hb% and the total worm burden. Conversely, the PCV and Hb% appeared to have a close relationship with the number of adult Haemonchus contortus present in the abomasum This research is an on going project and further the results would be evaluated in the near future.
Aging and Sexing of Skeletal finds
(University of Peradeniya, Peradeniya, 1996-08-10) Chandrasekara, M. S.; Wikramanayake, E. R.
The aging and sexing of two 12th century skeletons excavated in 1993 in Alahana Pirivena site in Polonnaruwa form the basis of the study. Skeleton No. 1 was of an individual of 5' 1/2" in length as measured in situ. Epiphyseal lines were seen in the partly fused upper and lower ends of the upper ann and forearm bones. The spheno-occipital synchondrosis was present. All maxillary and mandibular teeth were present with partly erupted third molars. With this, the age range can be limited to 16 - 18 years for a female and 18 - 20 years for a male. The muscle markings on the bones were not prominent. The sacrum showed the auricular surface extending up to 2 112segments suggesting that it is more likely to be a male. Skeleton No.2 was that of a heavily built individual. The saggital and coronal sutures of the skull were fused but the occipital and temporal sutures were partly fused. The premolar and molar teeth in both jaws showed attrition and exposure of dentine. From this data, the age of this individual was estimated to be around 55 years or more. Both the prominent muscle markings on bones and the prominent superciliary ridges indicate that this individual is a male.
An Alternating Method of Soaking Paddy for Parboling
(University of Peradeniya, Peradeniya, 1996-08-10) Ariyaratne, A. R.; Kathirgamu, K.
Poor quality parboiled rice is a resuh of improper soaking practices. Some farmers practice soaking paddy in running water to obtain higher quality parboiled rice. Based on this practice, an improved soaking method was designed and tested in this study to overcome the problems encountered in commercial level rice processing. Instead of submerged soaking in cold or hot water, spraying of cold water for different durations with varying idle times were applied to soak paddy samples. The spraying was done in 5, 10 and 15 minute durations. The interval between these sprays were varied by 30,60 and 90 minutes. These treatments were tested for 30, 36, 42 and 48 hours of total soaking periods. The soaked samples were steamed for 20 minutes under atmospheric pressure. Parboiled paddy samples were oven dried at 4SoC until moisture content reached 14- IS%. Milling was done in a rubber roll sheller and polished to remove 6% of bran by weight. The percentage of milling turnout, head rice yield and broken percentages were obtained from the samples. In addition, number of grains with white bellies were counted. Cooking quality was observed by sensory evaluation. Milling turnout was not significantly different among treatments at a given total soaking duration. The highest milling turnout was observed at the 48 hour total soaking duration. The percentage of white bellies decreased significantly with the increase in soaking period. In 48 hour soaking period, grains reached the 30% moisture content which is the required minimum for complete gelatinization of starch. In any soaking duration spraying resulted in less white bellies than the continuous soaking. The broken percentage in all treatments decreased with the increase in soaking duration. Treatments in spray soaking indicated significantly lower brokens than the continuous soaking treatments. In all the treatments, paddy samples soaked for 48 hours were cooked and taken for sensory evaluation. Colour, flavor, smell and general acceptability showed significant differences among treatments, and there was no significant difference in texture and stickiness at S% level. Paddy sprayed for IS minutes with 30 minute idling time for a total period of 48 hours scored highest in the sensory evaluation. The spray soaking of paddy can be used to improve the quality of parboiled paddy. The experimentation has to be conducted at commercial scale to develop the suitable design criteria.
Anthropometry of Veddas of Dambana
(University of Peradeniya, Peradeniya, 1996-08-10) Wikramanayake, E. R.; Chandrasekara, M. S.
Fourteen anthropometric measurements were made of the Veddas of Dambana in 1994/1995 using the same standard equipment and the same observers as in the study of the Hennanigala Veddas in 1993/1994. The results of the young adults of both sexes of the age range 22 - 35 years from the two studies were compared. No significant differences were found in twelve of the measurements in the females and ten in the males although all measurements were larger in the Dambana Veddas. Head circumference and sitting height were significantly different in the females (p <0.001 and p <0.05 respectively.) Head circumference, foot length, span and bicondylar diameter were significantly different in the males (p <0.05, P <0.02, P <0.01 and p <0.05 respectively). The results obtained for Dambana Veddas of both sexes were compared with 7 anthropometric measurements of Sinhalese undergraduates done in 1992. The differences in all parameters - height, sitting height, head length, head breadth, head circumference, bicondylar diameter and facial height were highly significant in the males (p <0.001). In the females, height, sitting height and facial height were not significantly different. The significant differences in morphometric traits between the Sinhalese and Veddas as reported from data of the National Ethnological Survey of 1936/1937 were still observed.
Antifertility Activity of Carica Papaya
(University of Peradeniya, Peradeniya, 1996-08-10) Nawarathnam, M.; Gunawardana, V. K.; Wimalasiri, W. R.; Pakiarajah, P.; Goonasekara, M. M.
There are widespread claims that certain plants have antifertility properties and the importance of plants as a source of antifertility drugs is well recognised (Farnsworth et al 1975). Such an agent would be useful particularly in the developing countries, since it would be cheaper. Also, a drug given in the form of a crude extract or semi-purified isolate would be more acceptable to rural people, in addition to being freely available. Carica papaya, the common papaw is a plant belonging to the family Caricacea. There are numerous reports from different parts of the world on the ethnomedical use of this plant as an anthelmintic, antibiotic, antipyretic and an insecticide. It has even been used as a substitute for tobacco in cigarettes. However, the most frequently cited uses of Carica papaya are on account of its activity on reproduction (Dhar et al 1978, Gopalakrishnan and Rajasekharasetty 1978). Oral administration of various parts of the plant, for example latex, fruit and seed, given as a water decoction is said to terminate pregnancy. In fact pregnant women in several countries such as Malaysia, India, Brazil and even in Sri Lanka are strictly prohibited from eating the fruit. There are also claims that the latex applied to the os uterus causes abortion. Despite these numerous reports the biological tests done on this plant are inadequate and inconclusive. Therefore the present work was undertaken to determine whether this plant has any activity which could cause termination of pregnancy. This investigation reports the potential antifertility activity of the seeds of Carica papaya. A bioassay routinely used in our laboratories to test plant extracts for antifertility activity was used in this study (Goonasekera et al 1995). An aqueous extract of sun-dried seed was prepared and yielded a dry weight equivalent of 40.6 g/kg when freeze dried. The dosage form was prepared by suspending the extract in distilled water, and the concentration was adjusted so that the maximum volume that could be administered to a rat did not exceed 0.2 ml. The rats used were of the Sprague-Dawley strain. The females were virgin rats 8-10 weeks of age and weighing 185-250 g. Their cyclicity was established by daily examination of vaginal smears. The males were less than 1 year of age, weighed 250-390 g and were proved fertile before use. The females were observed for two oestrus cycles and each female in proestrus was permitted access to a fertile male. Animals showing evidence of mating based on vaginal smears were divided into treated and control groups, each group consisting of ten rats. The extract was administered subcutaneously at a dose of 0.26 g/kg/day, for a period of ten days beginning on day 1 of pregnancy. The controls received distilled water. The vaginal smears and body weights were monitored daily. The females autopsied on day 16 revealed that although all rats were pregnant only three of the extract treated rats had normal foetuses. The mean number of foetuses in these three animals was 5.0 ± 2.6 compared to 9.5 ± 3.2 in the ten control rats. This difference was statistically significant. The number of implantation sites in the treated group was 8.25 ± 3.7 and that in the control group 9.7 ± 2.8. This difference was not statistically significant. The body weights of the rats in the control group showed a steady increase, but in the treated group although a gain in body weight was seen initially, this was not so after day 8 of pregnancy. The cessation of weight gain and the reduction in the number of normal foetuses suggest that the seeds of Carica papaya may have abortifacient activity in the rat. Further work aimed at determining the mode of action and the active ingredientls is continuing.
Antifungal Compounds in Freckle-Infected Bananas and Their Role in Anthracnose Development
(University of Peradeniya, Peradeniya, 1996-08-10) Abayasekara, C. L; Adikaram, N. K. B.
Freckle disease of banana caused by Phyllosticta musarum is widespread in Sri Lanka. While the disease continues to adversely affect the banana export industry, the freckled fruits are quite accepted by the local consumer. The disease is characterized by pin-head sized, restricted and isolated spots in the outer tissue layers of the fruit peel Freckles are rough to the touch and heavy infections may give a reddish-brown colour to the skin affecting the external appearance and lowering market quality (Abayasekara et all993). The infections that take place when the bunch is young do not expand into progressive rots during fruit ripening. The disease therefore does not result in quantitative losses. In contrast to freckle, the anthracnose disease (Colletotrichum musae) causes severe post harvest losses to ripe bananas in every banana growing region of the world . (Waller, 1992). The disease is generally controlled by post harvest treatment with fimgicides. In Sri Lanka too the anthracnose is the most damaging postharvest disease in banana, but no adequate control measures are practiced. The incidence of anthracnose disease was observed to be significantly less in freckle- infected fruits var. 'Ambul" (Mysoor, AAB group) than those without freckles. A negative correlation was observed between the density of freckle infections and the severity of anthracnose lesions that develop during fruit ripening. A similar trend was observed when unripe bananas having varied freckle spots were artificially inoculated with Cmusae where significantly lesser anthracnose lesion development occurred in heavily freckled fruits than those with lesser freckles. However, the anthracnose fimgus, C.musae, could be isolated more frequently from the surface-sterilized peel of freckled fruits than non-freckled fruits showing that more latent infections are found in the freckled fruit skin. This investigation has further shown that the freckle infection is associated with the accumulation of at least three phytoalexins in the peel tissues of unripe bananas. Peel tissues were excised from freckled and non-freckled unripe banana fruits separately and extracted in ethyl acetate by vacuum infiltration for 4 hours. The extracts were concentrated and bioassayed on thin layer chromatography plates using conidia of Cladosporium cladospoeioides or Cmusae. The extracts obtained from freckled fruit peel produced three antifungal zones. The most prominent antifimgal zone was at Rf 0.60, which was present in peels with low, moderate or high levels of freckling. The other two antifungal zones were observed only when freckling was moderate or high in the fruit peel, one being more prominent (RfO.3l) than the other. In general the total antifungal activity was greater in the heavily freckled bananas than those with moderate or low freckle infection. The extracts of healthy banana peels did not show any antifungal activity. Freckle- infected fruit peels continued to show antifungal activity during the ripening process. The antifungal activity could be detected even in fruits that are infected by the freckle fimgus at a very early stage of maturity. The results of the investigation indicate that the accumulation of antifungal substances in response to freckle infection may be a major factor that makes the banana fruits resistant to anthracnose disease. In order to chemically separate the antifungal compounds, a large scale extraction was carried out using 100 g of freckled peel tissue. The extract was fractionated by flash chromatography at the Department of Chemistry, the active fractions were identified by lLC- bioassay. The purification of antifungal constituents from the active fractions is at present in progress. This is the first record of accumulation of phytoalexins in response to freckle infection of banana fruit peel Earlier Mulvana et al, (1968) showed that ethanolic extracts from healthy, green Cavendish banana were antifungal and suggested that this might restrict the growth of C. musae in vivo. However, Muirhead (1981) found no evidence of a preformed antifungal compound that restricts the growth of C. musae. He attributed the antifungal activity to oxidation products formed during extraction from the phenolic compound, dopamine. In another investigation unripe bananas were inoculated with conidia of C. musae and the necrotic spots resuhed beneath the inoculum droplet, when bioassayed, contained five fungitoxic compounds. These compounds were not present in healthy tissues (Brown and Swinburne, 1980). The compounds produced in infected tissues apparently disappear with fruit ripening. There were no reports of any follow up work on these fungitoxic compounds. Induction of resistance has been shown to be an effective way of protecting plants from pathogen attack (Wilson et aI1994). Non-pathogenic or less aggressive microorganisms and mild strains of pathogens have been used to induce resistance in fruits and vegetables against postharvest pathogens. Strains of Penicillium funiculosum non-pathogenic to pineapple have been used to protect the fruits from pathogenic strains of this fungus (Lim and Rohrbach 1980). The present investigations have clearly indicated that the freckling induces fruit resistance to anthracnose through accunmIation of phytoalexins. Many Sri Lankans believe that the freckled banana fruits are more tastier than the non-freckled ones. Freckling appears to offer yet another advantage by naturally suppressing anthracnose disease. It is possible that the development of a strain of the freckle fungus or an elicitor, capable of inducing similar phytoalexin response without inflicting freckle symptoms, may help protect banana fruits from anthracnose.
Changes in Postharvest Disease Development and Ripening of 'Ambul' Bananas Treated with Acid and Alkaline Substances Compared to a Benlate Treatment
(University of Peradeniya, Peradeniya, 1996-08-10) Perera, N.; Karunaratne, A. M.
Some non-pesticidal postharvest treatments were tested on Ambul bananas to compare their effects with that of a commercial fungicide. Since it was found that the pH value of peels of Ambul bananas reduced from 5 to 4, with ripening, acid and alkaline substances were dissolved in distilled water separately, and were infiltrated into harvested fruits under pressure (4.3 x 10-3 Kg m-2) for 5 min. When a 0.4% NaHC03 solution was used, ripening and disease development were delayed by a day. When different concentrations of acetic acid were used, 0.2% acetic acid caused over 70% reduction of total disease, a 4 days' delay in disease appearance and a 2 days' delay in ripening. Dipping in Ben1ate (1.2g in II) for 10 min. eliminated diseases significantly, but the fruits ripened a day earlier than the controls. A 0.1% citric acid solution caused disease appearance to advance by a day. When conidia of Colletotrichum musae were inoculated on to a series of acidified Cook's No.2 broth cultures, the fungus did not grow below a pH of 4.0. Work is proceeding to determine the biochemical basis of these treatments.
Chemical Variations of Uncaria Ellipitca
(University of Peradeniya, Peradeniya, 1996-08-10) Chandrasena, W. D.; Diyabalanage, T. K. K.; Wannigama, G. P.
Uncaria elliptica is a woody climber, widely distributed in South and South East Asia. The species collected in Thailand and the species collected in Malaysia show chemical variations. This investigation reports chemical variations of the species within Sri Lanka itself Samples of the species were collected from the Kanneliya (KN) and Udawattakelle (UK) forest reserves. The KN plant and the UK plant showed minor differences in their triterpenoid compositions. The alkaloids of the two plants showed more striking differences. The KN plant gave ajmalicine, incorporating one molecule of tryptamine and one molecule of secologanin. The UK plant gave no ajmalicine, but gave the roxburghines, incorporating two molecules of tryptamine and one molecule of secologanin. The roxburghines are unique to the genus and among its 34 species, are found only in Uncaria elliptica.
Construction of an Improved Automatic Burette
(University of Peradeniya, Peradeniya, 1996-08-10) Tennakoon, D. T. B.; Bandara, H. M. N.; Chandrasena, W. D.; Ilangantilake, A. N.
We have previously described the construction of an automatic burette with the ability to detect the colour change at the end point. An ordinary burette modified for the purpose was used to control the addition of the titrant and the vohune was read visually. This instrument is now improved and the burette is replaced with a motor-driven plastic syringe. Once calibrated, the instrument is able to add and measure the vohune of the titrant with a high degree of accuracy. The process is fully computer controlled.
Controversies on the Aetiology of Endemic Goitre in Sri Lanka
(University of Peradeniya, Peradeniya, 1996-08-10) Areseculeratne, Y. M.; Reginald, G. J.; Hemawardana, D. M.; Weerasekara, G. A. B.; Tammita, A.
Endemic goitre is widely prevalent in the wet zone en Sri Lanka. The exact aetiology of endemic goitre has not been fully understood though iodine deficiency has been thought to be the commonest cause. This study involved the investigation of hundred and eleven euthyroid goitrous female patients with regard to their thyroid status. The gland was assessed according to the classification endorsed by the WHO and the International Council for the Control of Iodine Deficiency Disorders (lCCIDD), and categorised into 3 grades. The tests included measurement of total serum thyroxine, triiodothyronine and thyroid stimulating hormone levels and 2 and 24 hour iodine uptakes following the administration of a tracer dose of radioactive iodine. Thyroid hormone levels were found to be within the specified 'normal' ranges, but a trend was observed whereby an increase in goitre size was associated with a fall in total serum thyroxine levels, which was not significant, a rise in total triiodothyronine, being significant between grades 2 & 3 (p < 0.05), and a significant fall in serum thyroid stimulating hormone levels between grades 1 & 2 (p < 0.03), as well as between grades 2 & 3 (p < 0.05). The radioactive iodine uptakes at both 2 & 24 hours showed a rise with increase in the size of the gland, the uptakes between grades 2 & 3 were significant in both instances, (p < 0.01) and (p < 0.05) respectively. The biochemical picture seen in these patients is not in keeping with that seen in patients from areas en confirmed iodine deficiency.
Design and construction of a Digital vote counter
(University of Peradeniya, Peradeniya, 1996-08-10) Gammampila, S. P.; Uduwawala, K. R.; Sivakumar, V.; Premaratne, K.; Kareem, M. A.
In the present conventional voting procedure, each voter is expected to draw a cross in the cage against the name or the symbol of the candidate of his choice in the ballet paper provided to him Strict roles on the validity of a poll card such as the fact that the cross should not touch the adjoining cages, leads to a large percentage of invalid votes especially in countries like ours. It is also well known that some voters cast more than one vote using various illegal techniques. In this work we have designed and constructed digital vote counter with the aim that some of these difficulties could be overcome. This counter mainly consists of a receiving unit, logic system, and a result output unit. Here on the ballet card there is a hole for each candidate or his assigned symbol and the hole is covered by a sticker. The voter is expected to remove the sticker corresponding to the candidate of his choice and insert the card into the machine. If more than one sticker is removed or if no sticker is removed the logic system counts it as a rejected vote. Once the data is logically stored they are directed into the out put of the logic system Then the relays function in accordance with data and relevant data is shown in the seven segment display. The voter is not allowed to vote more than once since the machine rejects the second attempt till he or she leaves the place. As the counting is done electronically the results will be accurate and they can be released within a short time. Therefore, the use of such a machine in voting would be convenient, reliable and economical.
Determination of Iron Status in a Rural Population in Sri Lanka: Prevalence of Anaemia and Oral manifestations
(University of Peradeniya, Peradeniya, 1996-08-10) Ranasinghe, A. W.; Cuncheer, S.
The study was carried out using a randomly selected individuals from ten Grarna Sevaka divisions of Kadugannawa M 0 H division. A total of 339 patients were used in this study and a detailed questionnaire was administered to record socioeconomic and clinical data of the subjects. Intravenous blood was drawn to assess haemoglobin level, packed cell volume and the blood picture. The data analysis was done using a programme called EPI INFO Version 5. A total of 190 females and 149 of males were screened and their mean ages 49.2 + / - 14.1 and 46.5+ / - 15.6 years respectively. Only 2.7% of the patients were pure vegetarian and more than 85% of the patients consumed either fish. dry fish or chicken. However, around 50% of the group did not consume beef Only 8.3% of the patients gave a history of bleeding from the gastrointestinal tract, however, nearly 14% patients had menorrhgia Almost 50% of the study group had symptoms associated with anaemia. This high figure cannot be attributed purely to anaemia because some of these symptoms were common to anaemia as well as other disorders. e.g. angina. In contrast only 14% of the patients had signs of anaemia and females formed a higher percentage(78%) of this group compared to males(22%). Atrophy of the tongue was the commonest clinical abnormality(15%) followed by angular cheilitis(6.2%) and abnormalities like koilonychia and brittle nails were rare among the patients. Nearly 35.6% of the patients had a haemoglobin level less than 12 g/d1. however, when the cut-off point was lowered to 11 g/dl, the percentage of patients above this value rose to 81.9%. Even at this level nearly 20% of the population were anaemic which is a significant portion of the population and this data demonstrate the value of routine screening for anaemia in populations.
Discriminant anlysis of Cytomorphometric Measurements of oral epithelial cells in the Diagnosis of oral Premalignancy and Malignancy
(University of Peradeniya, Peradeniya, 1996-08-10) Ramaesh, T.; Mendis, B. R. R. N.; Rathnatunga, N. V. I.; Thattil, R. O.
The cytomorphometric measurements (nuclear diameter .and cell diameter) of oral epithelial cells were subjected to discriminant analysis for the diagnosis of oral premalignancy and malignancy. Of the group of oral premalignant diseases, leukoplakia was studied and the malignant group oral squamous cell carcinoma (OSCC) was studied. Smear and biopsy samples were collected from 136 lesions clinically diagnosed as oral leukoplakia or OSCC and 40 subjects with clinically normal buccal mucosa. The mean nuclear diameter (ND) and cell diameter (CD) values were obtained from the smears for each case. These samples were grouped according to the histopathological diagnosis. The study group is given below. When the discriminant analysis was carried out for nuclear and cell diameter values in between the groups, the discrimination was poor for group 2 and the normal samples whereas group 3 and group 4 were clearly discriminated from the normal samples (p < 0.05). The lesions with dysplasia (group 3) could be discriminated from lesions with hyperkeratosis, hyperplasia and acanthosis (group 2). Equations were obtained for discrimination between the groups in order to identify a new lesion as to which group it belongs. This shows that the discrimination of dysplastic lesions and squamous cell carcinoma from the normal and non-dysplastic lesions would be possible by cytomorphometric measurements of the oral smears.
Efect of Smoke Curing on some Foods in Sri Lanka
(University of Peradeniya, Peradeniya, 1996-08-10) Samarajeewa, U.; Wijeratne, M. C. P.; Rodrigo, M. C. P.; Karunaratne, G. D. D. P.
Foods are smoke cured for drying and to impart new organoleptic properties. The smoke produced during combustion and thermal decomposition of organic substances is a colloidal suspension of vapour, liquid droplets and solid particles. Chemically, the smoke contains organic acids, carbonyls, phenols and Polycyclic Aromatic Hydrocarbons (PAH). Some of the PAH are known carcinogens. Understanding of the presence and the mechanisms of contamination of foods by PAH is important from a health point of view and in processing offood. In Sri Lanka, copra and 'Maldive fish' are prepared by smoke curing. Eighty seven samples of coconut kernel products and twelve samples of 'Maldive fish' collected from the oil mills in the coconut triangle and markets in Kandy respectively were analyzed for PAH. The PAH from coconut samples were extracted in to hexane in Soxhlet and the 'Maldive fish' through dichloromethane using standard methods. The hexane extracts were purified by absorbing in to Sep-pak (Bond Elute LRC, Varian Inc.) cartridge and eluting with hexane-dichloromethane (3: 1). Estimation of PAH were done on Shimadzu model LC- 6A HPLC in reverse phase using a Chrompak Chrom Spher PAH glass cartridge, mobile phase of30 - 100% water:acetonitrile and a fluorescent detector. The mean total PAH concentrations observed in copra, coconut oil, copra meal and parings were 102 ± 184,359 ± 412, 68 ± 101 and 109 ± 164 mglkg respectively. More than 90% of the PAH detected were non-carcinogenic. Some of the sun-dried copra and desiccated coconuts did not contain PAR The concentrations ofPAH observed in Sri Lankan copra were much less than observed in copra in other countries of the region. The relatively low concentrations of PAH observed is probably associated with controlled combustion of shells practiced in 'Standard Ceylon Copra Kiln' which provides a relatively 'clean' supply of hot air. The distribution pattern of total PAH between oil and copra meal, compared to what is present in copra used to expel the oil indicate possible production of PAH during mechanical expulsion of oil in mills. The maldive fish contained mean total PAH concentration of 1083 ± 1332 mg/kg. The PAH concentrations in 'maldive fish' were 3 to 4 fold higher than what is reported in smoked salmon. However, the bulk of the PAH in 'maldive fish' were in the outer 2 mm crust which contained 60 to 90% of the PAH. The PAH in the innermost regions of the 'maldive fish' are probably either absorbed from smoke or produced due to heat. Both deposition and thermal generation ofPAH appear to occur in copra and 'maldive fish'. Preparation of regulatory limits for PAH in foods are still in an elementary stage. Germany has insisted on a regulatory limit of 25 mg/kg for total PAH and 5 mglkg for Benzo[ aJpyrene. In view of the concentrations observed in this study and else where it is more appropriate at this stage to classify food containing PAH to the following categories. Such a classification will enable the industries to reduce contamination by modification of smoke curing processes while meeting the day-to-day needs of the smoke cured foods.
Evaluation of a Malaria Antibody Elisa as a Malaria Screening Test for Blood Donors
(University of Peradeniya, Peradeniya, 1996-08-10) Wijesundera, M. De S.; Ranaweera, R. L. A. R.; Voller, A.; Bidwell, D. E.
A PI Antibody ELISA was validated for local use in screening blood donors from blood banks at Kandy, Peradeniya and Matale. A total of 1181 donors were screened. The pooled results of Kandy-Peradeniya showed a 9.5% positivity and for Matale it was 28.2%. Of 62 antibody positive sera tested for PI antigen carriage, 49(19"10) were found positive. All donors from Peradeniya were negative for parasites on blood films. Results indicate a need for routine serological screening of donors to limit the risk of transfusion malaria.
Factors Affecting the In-Situ conductivity of electronically conducting Polymers
(University of Peradeniya, Peradeniya, 1996-08-10) Vidanapathirana, K. P.; Senadeera, G. K. R.; Guanratne, L. M. W. K.; Kareem, A. M.; Dissanayake, M. A. K. L.
In recent years the discovery of doped organic polymers with high electronic conductivities has generated substantial research interest among physicists and chemists. Conjugated polymers such as polyacetylene, polypyrrole, polythiophene, polyparaphenylene with doped derivatives reported to have conductivities larger than 1 S/cm. The films obtained in organic media exhibit superior characteristics in favour of their conductivity and mechanical properties. However, the use of organic solvent is costly and hazardous. Hence the use of water as a solvent for the polymerization is evidently advantageous. Therefore, in this study, investigations have been carried out to find the effect of pH of the electrolyte, effect of the size of the dopant ion, effect of the electrolyte concentration and the effect of the current density used in the polymerization on the in-situ conductivity of poly N methyl pyrrole in aqueous media. The polymerization current density has the largest influence on the conductivity. The conductivity increase with the decreasing current density. pH of the electrolyte also effects the conductivity. The films formed using higher acidic media seems to have high conductivity. As seen in the non aqueous media, the conductivity changes with the size of the anion and the concentration of electrolyte.
Fodder Biomass Yield, Feeding Value and Palatabilty of Shrub Fodder Species Grown in Marginal Lands in the Mid Contry of Sri Lanka
(University of Peradeniya, Peradeniya, 1996-08-10) Perera, A. N. F.
Marginal lands in the mid country region are steep, heavily eroded and highly acidic. In most of these lands the top soil is limited to a very thin layer or completely cb;ent. Therefore, this study was conducted' to evaluate the potential of different shrub species for fodder biomass production. feeding value and preference by ruminants. This will provide an opportunity to introduce a profitable livestock. production system to generate a successful income source for the resource poor farmers in the mid country region. Legumes; Gliricidia sepium, Calliandra calothyrsus, Erythrina verigeta, Desmodium ransonii, F1emingia macrophylla and non legumes ; Tithonia diversifolia, Morus alba were established in double raw hedges, 7 meters apart. Leaf dry matter yields (LDMY) were estimated for 100m. linear lengths, with a lopping cycle of 16 weeks for a period of 1 year. Highest LDMY was observed in E. Verigeta (276±23 kg. DMIyear) and the lowest was in D. ransonii (86±12 kg. DMIyear). G. sepium, L. leucocephala, C. calothyrsus and F. macrophylla produced a LDMY of 205±17, 188±18, 165±10 and lOO±15 kglyear, respectively. Tithonia diversifolia and M .alba yielded 146±22 and 143±16 kgIyear, respectively. The Crude Protein (CP) content of leguminous shrub species ranged from 210±21 gIkg (F. macrophylla) to 270±21 gIkg (c. calothyrsus). In non leguminous species, T. diversifolia had a higher CP content (180±26 g/kg) than M alba (120±32 . lY'kg). Acid Detergent Fibre (ADF) in all fodder species were above 300±21 g/kg., and the highest . was in F. macrophylla (480±63 g/kg.), Lignin content was highly variable between species, from as low as 81±14 g/kg, (D. ransonii) to as high as 284±26 g/kg, (F. macrophyllay. The In Vitro dry matter digestibility (IVDMD) was above 500 gIkg. in all fodder species, except for F. macrophylla (466±124 g/kg.). The highest rapidly degradable fraction (a) was in G. sepium (42.0"10)and lowest in F macrophylla (24.4%). The potential degradability (a+b) was highest in T. diversifolia (79.4%). The highest soluble .fraction of nitrogen were in G. sepium and E. verigeta (59.1 % and 52.6%, respectively). All fodder species, except F. macrophyl/a and C. calothyrsus consist a potential degradable nitrogen (a+b), above 80%. The most preferred fodder species was M alba and the least preferred was F. macrophy/la (720 and 300 g. DMldIhead). This study suggest that the legwninous and non leguminous fodder species performed successfully in marginal lands and open an avenue for ruminant livestock production through providing quality fodder biomass for feeding.
High Ion Conducting 3D Network Poly(Ethylene Oxide)
(University of Peradeniya, Peradeniya, 1996-08-10) Perera, K. S.; Dissanayake, M. A. K. L.; Bandaranayake, P. W. S. K.
Studies of ionic conductivity in polymers complexed with divalent or trivalent cations are useful for understanding the parameters related to conductivity in polymers. In the present work a calcium salt has been selected since it is less hygroscopic than corresponding alkaline salts when dissolved in poly (ethylene oxide) network. The polycondensation between ex, ro - diol-poly (ethylene glycol), H(OCH2CH2).,OH with average MW 1000 and 3-chloro-2- chloromethyl-l-propane was done in the presence of excess KOH. The average molecular weight of the linear polycondensate determined by gel permeation chromatography was about 20,000. Cross-linking of linear polycondensate was done by free-radical polymerization using dibenzoyl peroxide as initiator to obtain a thin film of 3D network polymer. Membranes of 11 mm diameter were cut from the completely dried films. To prepare samples of different O/Ca ratio, calcium trifluoromethyl-sulphonate Ca(CF3S03h salt was dissolved in a small amount of acetonitrile and the membrane was put to absorb the whole solution. It was possible to prepare sample with O/Ca ratio from 8 to 100. Then the membranes were dried under vacuum at 90°C for one day. The electrical conductivity of membranes was measured under vacuum by a complex impedance technique in the temperature range from 90°C to room temperature. The maximum conductivity was obtained for O/Ca=25 which is about 2.0 x }O"4 S em" at 75°C and 1.0 x 10.5 S em" at room temperature. Polymers synthesized in this method have glass transition temperatures below room temperature and hence, give a very high ionic conductivity and have very good mechanical properties due to three dimensional link
Histopathological Changes in the Nervous System of Goats Affected with Enterotoxaemia
(University of Peradeniya, Peradeniya, 1996-08-10) De Silva, D. D. N.; Gunawardena, S. P. G. De S.
Enterotoxaemia caused by the toxins of Clostridium perfringens type D is an important disease of sheep and goats with a world wide distribution. The clinical manifestation of this condition is often associated with signs characteristic of nervous system disorders. Therefore, this investigation is aimed at studying the lesions in the nervous system of the goats affected with enterotoxaemia. Four Beetal goats with neurological manifestations, and belonging to the Nikaweratiya farm were included in this study. The animals aged between 2-4 years started showing neurological signs such as opisthotonus, ataxia, salivation, circling and nystagmus with a variable degree of paresis. Two of the animals were quadriplegic and showed excessive salivation, rapid breathing and hyperaesthesia. These severely affected animals succumbed to the condition within 36 hours after the onset of signs. Detailed necropsy and histopathological examinations were performed on the two dead animals and one animal which was sacrificed. Urine analysis and a toxicological study using intestinal contents for mouse inoculation were also performed. Necropsy revealed congestion and oedema of the lungs, hyperaemia 'and petechial haemorrhages in the small intestines and pulp like consistency of kidneys. Urine analysis revealed presence of glucose and protein. Presence of clostridial toxins in the intestines was demonstrated by the mouse inoculation test. Histological lesions were seen in the brain of all affected animals. These cerebral lesions were characterized by symmetrical focal areas of encephalomalacia. The early lesions showed oedema and the leakage of plasma and red blood cells from the veinules and capillaries in the affected areas. These lesions are characteristic of Enterotoxaemia and are useful in differentiating Enterotoxaemia from other neurological diseases in goats such as cerebrospinal nematodiasis and hypocalcaemia

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