Showing papers by "University of Peradeniya published in 2008"

Are Women More Credit Constrained? Experimental Evidence on Gender and Microenterprise Returns

Abstract: This paper analyzes data from a randomized experiment on mean returns to capital in Sri Lankan micro-enterprises. The findings show greater returns among men than among women; indeed, returns were not different from zero for women. The authors explore different explanations for the lower returns among female owners, and find no evidence that the gender gap is explained by differences in ability, risk aversion, or entrepreneurial attitudes. Differential access to unpaid family labor and social constraints limiting sales to local areas are not important. However, there is evidence that women invested grants differently from men. A smaller share of the smaller grants remained in the female-owned enterprises, and men were more likely to spend the grant on working capital and women on equipment. The gender gap is largest when male-dominated sectors are compared with female-dominated sectors, although female returns are lower than male returns even for females working in the same industries as men. The authors examine the heterogeneity of returns to determine whether any group of businesses owned by women benefit from easing capital constraints. The results suggest there is a large group of high-return male owners and a smaller group of poor, high-ability, female owners who might benefit from more access to capital.

Assessing Evidence for a Pervasive Alteration in Tropical Tree Communities

Abstract: In Amazonian tropical forests, recent studies have reported increases in aboveground biomass and in primary productivity, as well as shifts in plant species composition favouring fast-growing species over slow-growing ones. This pervasive alteration of mature tropical forests was attributed to global environmental change, such as an increase in atmospheric CO2 concentration, nutrient deposition, temperature, drought frequency, and/or irradiance. We used standardized, repeated measurements of over 2 million trees in ten large (16–52 ha each) forest plots on three continents to evaluate the generality of these findings across tropical forests. Aboveground biomass increased at seven of our ten plots, significantly so at four plots, and showed a large decrease at a single plot. Carbon accumulation pooled across sites was significant (+0.24 MgC ha−1 y−1, 95% confidence intervals [0.07, 0.39] MgC ha−1 y−1), but lower than reported previously for Amazonia. At three sites for which we had data for multiple census intervals, we found no concerted increase in biomass gain, in conflict with the increased productivity hypothesis. Over all ten plots, the fastest-growing quartile of species gained biomass (+0.33 [0.09, 0.55] % y−1) compared with the tree community as a whole (+0.15 % y−1); however, this significant trend was due to a single plot. Biomass of slow-growing species increased significantly when calculated over all plots (+0.21 [0.02, 0.37] % y−1), and in half of our plots when calculated individually. Our results do not support the hypothesis that fast-growing species are consistently increasing in dominance in tropical tree communities. Instead, they suggest that our plots may be simultaneously recovering from past disturbances and affected by changes in resource availability. More long-term studies are necessary to clarify the contribution of global change to the functioning of tropical forests.

Chronic renal failure among farm families in cascade irrigation systems in Sri Lanka associated with elevated dietary cadmium levels in rice and freshwater fish ( Tilapia )

Abstract: Chronic renal failure (CRF), in the main agricultural region under reservoir based cascade irrigation in Sri Lanka has reached crisis proportion Over 5,000 patients in the region are under treatment for CRF The objective of this study is to establish the etiology of the CRF Concentrations of nine heavy metals were determined in sediments, soils of reservoir peripheries, water and Nelumbo nucifera (lotus) grown in five major reservoirs that supply irrigation water All five reservoirs carried higher levels of dissolved cadmium (Cd), iron (Fe) and lead (Pb) Dissolved Cd in reservoir water ranged from 003 to 006 mg/l Sediment Cd concentration was 178–245 mg/kg No arsenic (As) was detected Cd content in lotus rhizomes was 25382 mg/kg The Provisional Tolerable Weekly Intake (PTWI) of Cd based on extreme exposure of rice is 8702–15927 μg/kg body weight (BW) for different age groups, 5–50 years The PTWI of Cd due to extreme exposure of fish is 6773–12469 μg/kg BW The PTWI on a rice staple with fish is 15475–28396 μg/kg BW The mean urinary cadmium (UCd) concentration in CRF patients of age group 40–60 years was 758 μg Cd/g creatinine and in asymptomatic persons UCd was 1162 μg Cd/g creatinine, indicating a chronic exposure to Cd The possible source of Cd in reservoir sediments and water is Cd-contaminated agrochemicals The CRF prevalent in north central Sri Lanka is a result of chronic dietary intake of Cd, supported by high natural levels of fluoride in drinking water, coupled with neglecting of routine de-silting of reservoirs for the past 20 years

Who Are the Microenterprise Owners? Evidence from Sri Lanka on Tokman v. de Soto

Abstract: Is the vast army of the self-employed in low income countries a source of employment generation? This paper uses data from surveys in Sri Lanka to compare the characteristics of own account workers (non-employers) with wage workers and with owners of larger firms. The authors use a rich set of measures of background, ability, and attitudes, including lottery experiments measuring risk attitudes. Consistent with the International Labor Organization's views of the self employed (represented by Tokman), the analysis finds that two-thirds to three-quarters of the own account workers have characteristics which are more like wage workers than larger firm owners. This suggests the majority of the own account workers are unlikely to become employers. Using a two and a half year panel of enterprises, the authors show that the minority of own account workers who are more like larger firm owners are more likely to expand by adding paid employees. The results suggest that finance is not the sole constraint to growth of microenterprises, and provides an explanation for the low rates of growth of enterprises supported by microlending.

Effect of plasticizers (EC or PC) on the ionic conductivity and thermal properties of the (PEO)9LiTf: Al2O3 nanocomposite polymer electrolyte system

Abstract: A new plasticized nanocomposite polymer electrolyte based on poly (ethylene oxide) (PEO)-LiTf dispersed with ceramic filler (Al2O3) and plasticized with propylene carbonate (PC), ethylene carbonate (EC), and a mixture of EC and PC (EC+PC) have been studied for their ionic conductivity and thermal properties. The incorporation of plasticizers alone will yield polymer electrolytes with enhanced conductivity but with poor mechanical properties. However, mechanical properties can be improved by incorporating ceramic fillers to the plasticized system. Nanocomposite solid polymer electrolyte films (200-600 mu m) were prepared by common solvent-casting method. In present work, we have shown the ionic conductivity can be substantially enhanced by using the combined effect of the plasticizers as well as the inert filler. It was revealed that the incorporating 15 wt.% Al2O3 filler in to PEO: LiTf polymer electrolyte significantly enhanced the ionic conductivity [sigma(RT) (max)= 7.8 x 10(-6) S cm(-1)]. It was interesting to observe that the addition of PC, EC, and mixture of EC and PC to the PEO: LiTf: 15 wt.% Al2O3 CPE showed further conductivity enhancement. The conductivity enhancement with EC is higher than PC. However, mixture of plasticizer (EC+PC) showed maximum conductivity enhancement in the temperature range interest, giving the value [sigma(RT) (max)= 1.2 x 10(-4) S cm(-1)]. It is suggested that the addition of PC, EC, or a mixture of EC and PC leads to a lowering of glass transition temperature and increasing the amorphous phase of PEO and the fraction of PEO-Li+ complex, corresponding to conductivity enhancement. Al2O3 filler would contribute to conductivity enhancement by transient hydrogen bonding of migrating ionic species with O-OH groups at the filler grain surface. The differential scanning calorimetry thermograms points towards the decrease of T-g, crystallite melting temperature, and melting enthalpy of PEO: LiTf: Al2O3 CPE after introducing plasticizers. The reduction of crystallinity and the increase in the amorphous phase content of the electrolyte, caused by the filler, also contributes to the observed conductivity enhancement.

Frequent and potentially fatal envenoming by hump-nosed pit vipers (Hypnale hypnale and H. nepa) in Sri Lanka: lack of effective antivenom

Abstract: In a prospective study of snake bites involving 10 hospitals in Sri Lanka, 302 (35%) of 860 patients with bites by identified snakes proved to have been bitten by hump-nosed pit vipers (301 by Hypnale hypnale and 1 by H. nepa). Most victims were males aged between 11 years and 50 years who had been bitten on their feet or ankles while walking at night close to their homes. There was local swelling in 276 (91%) and local necrosis in 48 (16%). Eleven (4%) required amputation of fingers or toes and 12 (4%) received skin grafts. In 117 patients (39%) blood incoagulability was first detected between 15 min and 48 h after the bite, and in 116 of them this was present on admission to hospital. Spontaneous systemic bleeding was observed in 55 patients (18%). Acute renal failure developed in 10%, five of whom died to give an overall case fatality rate of 1.7%. Thus, bites by hump-nosed pit vipers can cause debilitating local and fatal systemic envenoming. In Sri Lanka and southwestern India where bites by these snakes are common, the only available antivenoms (raised against cobra, krait, Russell's viper and saw-scaled viper venoms) are ineffective and carry a high risk of reactions.

Improvement in survival after paraquat ingestion following introduction of a new formulation in Sri Lanka.

Abstract: BACKGROUND: Pesticide ingestion is a common method of self-harm in the rural developing world In an attempt to reduce the high case fatality seen with the herbicide paraquat, a novel formulation (INTEON) has been developed containing an increased emetic concentration, a purgative, and an alginate that forms a gel under the acid conditions of the stomach, potentially slowing the absorption of paraquat and giving the emetic more time to be effective We compared the outcome of paraquat self-poisoning with the standard formulation against the new INTEON formulation following its introduction into Sri Lanka METHODS AND FINDINGS: Clinical data were prospectively collected on 586 patients with paraquat ingestion presenting to nine large hospitals across Sri Lanka with survival to 3 mo as the primary outcome The identity of the formulation ingested after October 2004 was confirmed by assay of blood or urine samples for a marker compound present in INTEON The proportion of known survivors increased from 76/297 with the standard formulation to 103/289 with INTEON ingestion, and estimated 3-mo survival improved from 271% to 367% (difference 95%; 95% confidence interval [CI] 20%-171%; p = 0002, log rank test) Cox proportional hazards regression analyses showed an approximately 2-fold reduction in toxicity for INTEON compared to standard formulation A higher proportion of patients ingesting INTEON vomited within 15 min (38% with the original formulation to 55% with INTEON, p < 0001) Median survival time increased from 23 d (95% CI 12-34 d) with the standard formulation to 69 d (95% CI 33-107 d) with INTEON ingestion (p = 0002, log rank test); however, in patients who did not survive there was a comparatively smaller increase in median time to death from 09 d (interquartile range [IQR] 05-34) to 15 d (IQR 05-55); p = 002 CONCLUSIONS: The survey has shown that INTEON technology significantly reduces the mortality of patients following paraquat ingestion and increases survival time, most likely by reducing absorption Language: en

The spectrum of intermediate syndrome following acute organophosphate poisoning: a prospective cohort study from Sri Lanka.

Abstract: Background Intermediate syndrome (IMS) is a major cause of death from respiratory failure following acute organophosphate poisoning. The objective of this study was to determine repetitive nerve stimulation (RNS) predictors of IMS that would assist in patient management and clinical research. Methods and Findings Seventy-eight consenting symptomatic patients with organophosphate poisoning were assessed prospectively with daily physical examination and RNS. RNS was done on the right and left median and ulnar nerves at 1, 3, 10, 15, 20, and 30 Hz. The study was conducted as a prospective observational cohort study in the Central Province, Sri Lanka. IMS was diagnosed in ten out of 78 patients using a priori clinical diagnostic criteria, and five of them developed respiratory failure. All ten patients showed progressive RNS changes correlating with the severity of IMS. A decrement-increment was observed at intermediate and high frequencies preceding the onset of clinical signs of IMS. As the patient developed clinical signs of IMS, decrement-increment was progressively noted at low and intermediate frequencies and a combination of decrement-increment and repetitive fade or severe decrement was noted at high frequencies. Severe decrement preceded respiratory failure in four patients. Thirty patients developed forme fruste IMS with less severe weakness not progressing to respiratory failure whose RNS was characterized by decrement-increment or a combination of decrement-increment and repetitive fade but never severe decrements. Conclusions Characteristic changes in RNS, preceding the development of IMS, help to identify a subgroup of patients at high risk of developing respiratory failure. The forme fruste IMS with the characteristic early changes on RNS indicates that IMS is a spectrum disorder. RNS changes are objective and precede the diagnosis and complications of IMS. Thus they may be useful in clinical management and research.

Multiple insecticide resistance mechanisms involving metabolic changes and insensitive target sites selected in anopheline vectors of malaria in Sri Lanka

Abstract: The current status of insecticide resistance and the underlying resistance mechanisms were studied in the major vector of malaria, Anopheles culicifacies, and the secondary vector, Anopheles subpictus in five districts (Anuradhapura, Kurunegala, Moneragala, Puttalam and Trincomalee) of Sri Lanka. Eight other anophelines, Anopheles annularis, Anopheles barbirostris, Anopheles jamesii, Anopheles nigerrimus, Anopheles peditaeniatus, Anopheles tessellatus, Anopheles vagus and Anopheles varuna from Anuradhapura district were also tested. Adult females were exposed to the WHO discriminating dosages of DDT, malathion, fenitrothion, propoxur, λ-cyhalothrin, cyfluthrin, cypermethrin, deltamethrin, permethrin and etofenprox. The presence of metabolic resistance by esterase, glutathione S-transferase (GST) and monooxygenase-based mechanisms, and the sensitivity of the acetylcholinesterase target site were assessed using synergists, and biochemical, and metabolic techniques. All the anopheline species had high DDT resistance. All An. culicifacies and An. subpictus populations were resistant to malathion, except An. culicifacies from Kurunegala, where there was no malathion carboxylesterase activity. Kurunegala and Puttalam populations of An. culicifacies were susceptible to fenitrothion. All the An. culicifacies populations were susceptible to carbamates. Both species were susceptible to the discriminating dosages of cypermethrin and cyfluthrin, but had different levels of resistance to other pyrethroids. Of the 8 other anophelines, only An. nigerrimus and An. peditaeniatus were resistant to all the insecticides tested, probably due to their high exposure to the insecticides used in agriculture. An. vagus showed some resistance to permethrin. Esterases, GSTs and monooxygenases were elevated in both An. culicifacies and An. subpictus. AChE was most sensitive to insecticides in Kurunegala and Trincomalee An. culicifacies populations and highly insensitive in the Trincomalee An. subpictus population. The complexity of the resistance segregating in these field populations underlines the need for new molecular tools to identify the genomic diversity, differential upregulation and different binding specificities of resistance conferring genes, and the presence of different subspecies with different vectorial capacities.

Heavy metal poisoning from Ayurvedic traditional medicines: an emerging problem?

Abstract: The use of Ayurvedic medicines is common in both adults and children and is increasing in many areas of the world. This paper will discuss the risks of heavy metal poisoning associated with the use of Ayurvedic medicines and illustrate this with some cases managed by the authors. Many Ayurvedic medicines contain heavy metals, including lead, mercury and arsenic, and there have been numerous reports of clinically significant heavy metal poisoning related to their use. However, there have been few studies that allow quantification of the incidence of this problem. There is limited regulation of these products in most areas of the world. Recent European legislation may help to improve safety of products bought in shops, but it is likely to have a relatively limited overall impact as it will not cover personal imports or products prescribed by traditional medicine practitioners. There is an urgent need for studies to quantify the frequency and potential risk of heavy metal poisoning from Ayurvedic medicines and for culturally appropriate education to inform the public of the potential for toxicity associated with these products.

Reproduction in domestic buffalo.

Abstract: The domestic buffalo is an indispensable livestock resource to millions of smallholder farmers in developing countries, particularly in Asia. Although its reproductive biology is basically similar to that of cattle, there are important differences and unique characteristics that need to be considered in order to apply modern reproductive technologies to improve its productivity. Under most smallholder production systems, the reproductive efficiency of buffalo is compromised by factors related to climate, management, nutrition and diseases. However, when managed and fed properly, buffalo can have good fertility and provide milk, calves and draught power over a long productive life. The basic technical problems associated with artificial insemination in buffalo were largely overcome two decades ago, but the technology has not had the expected impact in some developing countries, because largely of infrastructural and logistic problems. Approaches involving the use of hormones for treating anoestrus and for synchronizing oestrus have had varying rates of success, depending on the protocols used and the incidence of underlying problems that cause infertility. Embryo technologies such as multiple ovulation embryo transfer, in vitro embryo production, cryopreservation and cloning are being intensively studied but have had far lower success rates than in cattle. Improving the productivity of buffalo requires an understanding of their potential and limitations under each farming system, development of simple intervention strategies to ameliorate deficiencies in management, nutrition and healthcare, followed by judicious application of reproductive technologies that are sustainable with the resources available to buffalo farmers.

Antimicrobials as a contributory factor in oral candidosis – a brief overview

Abstract: The advent of the human immunodeficiency virus infection and the increasing prevalence of compromised individuals in the community due to modern therapeutic advances have resulted in a resurgence of opportunistic infections, including oral candidosis, which is by far the most common oral fungal infection in man. Broad-spectrum antibiotics used in the treatment of a wide range of disease conditions have also been attributed as a predisposing factor of oral candidosis. In this mini review we discuss the research findings on the relationship between antibiotics and oral candidosis and possible mechanisms of pathogenicity following such therapy.

Entrepreneurial Motivation in Developing Countries: What Does 'Necessity' and 'Opportunity' Entrepreneurship Really Mean?

Abstract: The paper examines the relationship between the state of necessity and entrepreneurial activity, through qualitative case studies from Uganda and Sri Lanka, and a survey of 1006 Ugandan adults. Questions are posed on the tenability of hypothesis that necessity is a primary motive for business start-up in poor countries. The relationship between necessity and business start-up, though significant, is in the opposite direction from that predicted by the "necessity hypothesis". Those with low incomes were much less likely to start a business, because they often became "trapped" by having to work long hours for just enough income to survive. Opportunistic diversification, however, flourished once resources improved. The results question recent attempts to classify countries on the basis of distinctive forms of entrepreneurship based on necessity and opportunity.

Increasing the dose of prednisolone during viral infections reduces the risk of relapse in nephrotic syndrome: a randomised controlled trial

Abstract: Background: Relapses of nephrotic syndrome are often triggered by viral upper respiratory tract infections (URTIs), possibly mediated by cytokine release. Objective: To test, in a randomised double-blind placebo-controlled crossover trial, the hypothesis that a small short-term increase in the dose of prednisolone will reduce the release of cytokines and thereby reduce the risk of relapse. Methods: Sequential patients receiving low-dose ( Results: 48 patients were recruited, and 40 completed the trial (29 male; 11 female). Age at entry ranged from 1.5 to 13.2 (median 5.3) years. The relapse rate after viral URTI was 19/40 (48%) in the placebo group and 7/40 (18%) in the prednisolone group (p = 0.014; two-sided probability using Fisher’s exact test). Conclusion: Prescribing prednisolone daily for 7 consecutive days at the same dose as that taken by the patient on an alternate-day basis at the onset of a presumed viral URTI significantly reduces the risk of relapse in children with steroid-dependent nephrotic syndrome.

Upregulation of HIF-1alpha in malignant transformation of oral submucous fibrosis.

Abstract: Background: Oral submucous fibrosis (OSF) is a precancerous condition showing extensive fibrosis of the submucosa and affects most parts of the oral cavity, including pharynx and upper third of the oesophagus. The molecules involved in the biological pathways of the fibrotic process appeared to be either down- or upregulated at different stages of the disease. Despite the precancerous nature, malignant transformation of the epithelium in the background of fibrosis has not been studied in detail. HIF-1 alpha is a known transcription factor that is induced by hypoxia. Aims: To test the hypothesis that hypoxia plays a role in malignant transformation and progression of OSF. Materials and Methods: We used both formalin-fixed and frozen samples of OSF and normal mucosa to investigate the relationship between HIF-1 alpha and epithelial dysplasia using immunohistochemistry and RT-PCR. Conclusions: Our data indicate that HIF-1 alpha is upregulated at both protein and mRNA levels in OSF and the correlation with epithelial dysplasia is statistically significant (P < 0.001). We propose that HIF-1 alpha may play a role in malignant transformation of OSF. Further, over-expression of HIF-1alpha may contribute to the progression of fibrosis. It may be possible to use HIF-1 alpha as a marker for malignant transformation of OSF.

Prostaglandin F2α increases endothelial nitric oxide synthase in the periphery of the bovine corpus luteum: the possible regulation of blood flow at an early stage of luteolysis

Abstract: Prostaglandin F(2)(alpha) (PGF(2)(alpha)) released from the uterus causes alterations in luteal blood flow, reduces progesterone secretion, and induces luteolysis in the bovine corpus luteum (CL). We have recently discovered that luteal blood flow in the periphery of the mature CL acutely increases coincidently with pulsatile increases in a metabolite of PGF(2)(alpha) (PGFM). In this study, we characterized changes in regional luteal blood flow together with regional alterations in endothelial nitric oxide synthase (eNOS) expression during spontaneous luteolysis and in response to PGF(2)(alpha). Smooth muscle actin-positive blood vessels larger than 20 microm were observed mainly in the periphery of mature CL. PGF(2)(alpha) receptor was localized to luteal cells and large blood vessels in the periphery of mid-CL. PGF(2)(alpha) acutely stimulated eNOS expression in the periphery but not in the center of mature CL. Injection of the NO donor S-nitroso-N-acetylpenicillamine into CL induced an acute increase in luteal blood flow and shortened the estrous cycle. In contrast, injection of the NOS inhibitor l-NAME into CL completely suppressed the acute increase in luteal blood flow induced by PGF(2)(alpha) and delayed the onset of luteolysis. In conclusion, PGF(2)(alpha) has a site-restricted action depending on not only luteal phase but also the region in the CL. PGF(2)(alpha) stimulates eNOS expression, vasodilation of blood vessels, and increased luteal blood flow in periphery of mature CL. Furthermore, the increased blood flow is mediated by NO, suggesting that the acute increase in peripheral blood flow to CL is one of the first physiological indicators of NO action in response to PGF(2)(alpha).

The effect of tobacco smoking and of betel chewing with tobacco on the buccal mucosa: a cytomorphometric analysis.

Abstract: The effect of tobacco use on the buccal mucosa has been assessed by cytomorphometry. Cell and nuclear diameters (CD, ND) of exfoliated oral squames were measured in tobacco smokers (S), betel chewers with tobacco (C) and those with a combined habit (S+C). Non-users (NU) served as controls. The mean CD values in S, C, S+C and NU were: 50.8 (+/-0.47), 49.39 (+/-0.48), 49.12 (+/-0.47) and 51.87 (+/-0.76) microm, and the mean ND values were: 8.83 (+/-0.07), 8.61 (+/-0.08), 8.72 (+/-0.10) and 8.33 (-/+ 0.09) microm, respectively. The least significant difference procedure (LSD at P=0.05) showed a significant reduction for CD in C and S+C and an increase for ND in all three habit groups, compared to the controls. This study shows that the use of tobacco influences the cytomorphology of the normal buccal mucosa. Betel chewing with tobacco influences the ND and CD, while smoking influences only the ND.

Characterization of knockdown resistance in DDT- and pyrethroid-resistant Culex quinquefasciatus populations from Sri Lanka

Abstract: DDT and pyrethroid resistance in Culex quinquefasciatus have been previously reported in Sri Lanka, but the mechanisms involved have yet to be characterized. We report the presence of two mutant alleles of the sodium channel gene, the target site for both DDT and pyrethroid insecticides. Both mutations resulted in classic knockdown resistance (kdr) L1014F mutation because of either an A-to-T substitution or an A-to-C substitution. We developed two alternative assays to distinguish between the two mutations and used these to screen 214 individuals from nine geographic locations throughout Sri Lanka. Very high levels of kdr mutations were found throughout the country. A predominance of the A-to-C mutation was observed over the A-to-T with an average allele frequency of 50% and 2%, respectively. In addition to these non-synonymous kdr substitutions, we also found an indel (TCACA) in the intron downstream of the kdr mutation. After genotyping this indel in 136 individuals, we found no evident correlation between kdr genotypes and intronic indel. The presence of two alternative kdr mutations has implications for the reliance on single molecular diagnostics for detection of resistance in field populations. Furthermore, the high levels of these kdr mutations in C. quinquefasciatus populations throughout Sri Lanka are of concern for the future of pyrethroid-based control programmes on this island.

Physicochemical Properties of Starches from Sri Lankan Rice Varieties

Abstract: Physico-chemical properties; amylose content, swelling power, pasting properties by Rapid Visco Analyzer (RVA), thermal properties by Differential Scanning Calorimeter (DSC), and enzymatic digestibility of starches isolated from 19 different Sri Lankan rice varieties were analyzed. Significant variation was shown in all the tested properties among tested varieties in which the amylose content varied from 16.0% to 34.7%. Amylose content appears to be the major factor controlling almost all physico-chemical properties of rice starch, as it showed significant correlations to all other properties tested. It correlated negatively to the peak and breakdown viscosities by RVA and enzyme digestibility but positively to all other tested properties. The peak and onset gelatinization temperatures and enzyme digestibility correlated to all properties except enthalpy for starch gelatinization. The peak and onset gelatinization temperatures, as well as the blue value, showed negative correlations to the peak and breakdown viscosities, indicating the importance of low amylose for easy starch pasting. According to our results, low amylose starches started to gelatinize at lower temperatures. During heating and cooling, such starch slurry showed higher peak and breakdown viscosities, but resulted in a softer gel. Low amylose starch was also easily digestible by enzymes. These properties are probably associated with the reduced compactness in the amorphous area of starch granules. Due to lower amylose in the amorphous area, loosely packed starch granules result in higher swelling power and disorganization with heating.

Psychological autopsy study of suicide in three rural and semi-rural districts of Sri Lanka

Abstract: Background Knowledge concerning the epidemiology of suicide in Sri Lanka is limited despite its suicide rates being amongst the highest in the world.

PEDOT and PPy conducting polymer bilayer and trilayer actuators

Abstract: Actuators based on conducting polymers are attracting increasing interest due to their desirable features such as large mechanical stress generated, sufficient maximum strain values, high reversibility, good safety properties and the possibility of precise control using small voltages. Many attempts have been made to improve the actuator performance. We report electromechanical measurements on actuators of bilayer and trilayer free standing films prepared with polypyrrole (PPy) and poly(3,4-ethylenedioxythiophene) (PEDOT) conducting polymers. Both types of conducting polymer are pre-doped during synthesis with dodecyl benzenesulfonate (DBS). These multilayer films were prepared electrochemically so that the PEDOT layer is very thin compared to that of the PPy layer. In the trilayer film, the PEDOT layer is sandwiched between two PPy layers. The films were characterized electromechanically and the results compared with those of PPy single layer film. Bilayer films show a significant increase in the strain measured at higher scan rates (>100 mV s −1 ). The force difference generated between the reduced and oxidized states is much higher for trilayer films and higher for bilayer films than that in a single layer of PPy. Trilayer films are both stronger and faster than a single layer PPy film of half the thickness.

Impact of harvesting on constructed wetlands performance - a comparison between Scirpus grossus and Typha angustifolia.

Abstract: Three units of free water surface (FWS) constructed wetlands treating domestic wastewater under tropical conditions were examined in terms of water quality and biomass characteristics. One unit (L2) was planted with Scirpus grossus, one with Typha angustifolia (L3), and the unplanted third (L1) served as control. Influent and effluent quality parameters: biological oxygen demand (BOD5), nitrate (NO3 −-N), ammonium (NH4 +-N), phosphorus (P), total suspended solids (TSS) and fecal coliforms were regularly measured. The average BOD5 reductions were 37.0%, 58.5%, and 53.8% for units L1, L2, and L3, respectively. The planted units removed pollutants more effectively although there was no significant difference between the Scirpus grossus and Typha angustifolia units. Plant growth was monitored in marked quadrats by measuring shoot height and other growth parameters. The above-ground organs in L2 and L3 was harvested whenever the shoots reached maximum shoot height and formed flowers. Scirpus grossus had sustai...

Self-poisoning in rural Sri Lanka: small-area variations in incidence

Abstract: Self-poisoning is one of the most common methods of suicide worldwide. The intentional ingestion of pesticides is the main contributor to such deaths and in many parts of rural Asia pesticide self-poisoning is a major public health problem. To inform the development of preventive measures in these settings, this study investigates small-area variation in self-poisoning incidence and its association with area-based socioeconomic and agricultural factors. Ecological analysis of intentional self-poisoning in a rural area (population 267,613) of Sri Lanka in 2002. The geographic distribution of cases was mapped to place of residence. Using administrative division (GN), median population size 1416, as unit of analysis, associations with socioeconomic and agricultural indicators were explored using negative binomial regression models. The overall incidence of intentional self-poisoning in the study area was 315 per 100,000 (range: 0 – 2168 per 100,000 across GNs). Socioeconomic disadvantage, as indexed by poor housing quality (p = 0.003) and low levels of education (p < 0.001) but not unemployment (p = 0.147), was associated with a low self-poisoning incidence. Areas where a high proportion of the population worked in agriculture had low overall levels of self-poisoning (p = 0.002), but a greater proportion of episodes in these areas involved pesticides (p = 0.01). An association with extent of cultivated land was found only for non-pesticide poisoning (p = 0.01). Considerable small-area variation in incidence rates of intentional self-poisoning was found. The noteworthy concentration of cases in certain areas and the inverse association with socioeconomic deprivation merit attention and should be investigated using individual-level exposure data.

An altered keratinocyte phenotype in oral submucous fibrosis: correlation of keratin K17 expression with disease severity

Abstract: Oral submucous fibrosis (OSF) is characterized by abnormal collagen metabolism in the submucosal connective tissue. Its influence on the overlying epithelium is not known but about 14% of OSF cases undergo malignant transformation to squamous cell carcinoma indicating association with abnormality of the epithelium. Here, we have defined the keratin expression profile, by immunohistochemistry and quantitative image analysis, using a panel of 22 anti-keratin monoclonal antibodies on 28 OSF samples. We observed an increase of K1 and K10 in the suprabasal layers, induction of K6 in the basal layer and complete loss of K19 in the epithelium. Furthermore, there was increased K17 expression in the suprabasal layers, which correlated with disease severity. In a subset of the most severe OSF cases (14%), K17 expression was completely lost in the basal layer which might define them to be at most risk to undergo malignant transformation. There was no detectable expression of K8, K18, K7 and K9 and the expression of K4, K13, K14, K15 and K16 did not change in OSF. We propose that the altered keratin profiles could be useful as histological diagnostic markers and provide important insights into the pathogenesis of the disease and its predisposition to malignancy.

Androgenic potential in coconut ( Cocos nucifera L.)

Abstract: Conditions for induction of androgenesis in coconut cv. Sri Lanka Tall were studied. Anthers collected from inflorescences at four maturity stages were given heat (38°C) or cold (4°C) pretreatments for 1, 3, 6 and 14 days, either prior to or post inoculation. Three different basal media and different anther densities were also tested. Androgenesis was observed only in anthers collected from inflorescences 3 weeks before splitting (WBS) and after a heat pretreatment at 38°C for 6 days. Modified Eeuwens Y3 liquid medium supplemented with 100 μM 2,4-dichlorophenoxyacetic acid (2,4-d), 0.1% activated charcoal and 9% sucrose was effective in inducing an androgenic response. The lowest anther density tested, 10 per petri plate, was found to be the optimal density. When androgenic calli or embryos were subcultured to Y3 medium containing 66 μM 2,4-d, followed by transfer to Y3 medium without plant growth regulators and finally to Y3 medium containing 5 μM 6-benzyladenine (BA) and 0.35 μM gibberellic acid (GA3), plantlets regenerated at a frequency of 7%. Histological study indicated that the calli and embryos originated from the inner tissues of the anthers. Ploidy analysis of calli and embryos showed that they were haploid. This is the first report of successful androgenesis yielding haploid plants from coconut anthers.

Spatial and temporal changes of hydrogeochemistry in ancient tank cascade systems in Sri Lanka : evidence for a constructed wetland

Abstract: The tank cascade system (TCS) in Sri Lanka is one of the most advanced water-conveyance mechanisms among the medieval hydraulic civilizations in the world. In this study, temporal and spatial variations of the hydrogeochemistry of a small cascade system were investigated. A cascade system at Malagane in the Deduru Oya basin, located in the north-west of Sri Lanka, was selected. Measurements of pH, electrical conductivity (EC), nitrates, nitrites, phosphates, sulphates, alkalinity, chloride, Na, K, Ca, Mg, Fe and Mn were carried out fortnightly throughout the year, to understand the nutrient dynamics in TCSs. Most parameters show a decreasing trend when water passes through ‘Thaulla’, which is located in the upper peripheral region of the tank. However, phosphate behaves differently, probably due to human activities that dominated along the tank bund. The results suggested that Thaulla, which abounds with numerous hydrophytes, acts as an active ‘constructed wetland’ and efficiently removes pollutants in order to sustain the system. The water quality monitoring described in this paper provides evidence for the wetland function of Thaulla in the ancient irrigation hydraulic system in Sri Lanka.