Higher Performance of DSSC with Dyes from Cladophora sp. as Mixed Cosensitizer through Synergistic Effect.

Chlorophyll and xanthophyll dyes extracted from a single source of filamentous freshwater green algae (Cladophora sp.) were used to sensitize dye sensitized solar cells and their performances were investigated. A more positive interaction is expected as the derived dyes come from a single natural source because they work mutually in nature. Cell sensitized with mixed chlorophyll and xanthophyll showed synergistic activity with improved cell performance of 1.5- to 2-fold higher than that sensitized with any individual dye. The effect of temperature and the stability of these dyes were also investigated. Xanthophyll dye was found to be more stable compared to chlorophyll that is attributed in the ability of xanthophyll to dissipate extra energy via reversible structural changes. Mixing the dyes resulted to an increase in effective electron life time and reduced the process of electron recombination during solar cell operation, hence exhibiting a synergistic effect.

Kikuchi-Fujimoto's disease: a case series from Sri Lanka.

INTRODUCTION: Kikuchi's disease is a rare, benign, self-limiting disease, mainly involving the lymph nodes of young people. The etiology is unknown. Clinical symptoms and basic investigations may mimic lymphomas and chronic granulomatous conditions like tuberculosis. Lymph node biopsy shows characteristic diagnostic features. Even though described internationally, the local disease pattern or incidence has not been well studied. METHODS: We studied all patients who were diagnosed with Kikuchi's disease at Teaching Hospital, Peradeniya from January 2011 to April 2012. RESULTS: A total of 9 cases showed histopathological features of Kikuchi's disease. All patients were females, in the age group of 12-30 years having fever and lymphadenopathy. They carried a provisional diagnosis of lymphoma, tuberculosis or reactive lymphadenitis. CONCLUSIONS: Necrotising lymphadenitis has a predilection for cervical lymph nodes of females and is usually accompanied by fever. Clinical features can resemble tuberculous lymphadenitis or malignant lymphoma. Excision biopsy of the involved node is mandatory for the diagnosis.

The prevalence of symptoms of Post-Traumatic Stress Disorder among soldiers with amputation of a limb or spinal injury: a report from a rehabilitation centre in Sri Lanka.

Post-Traumatic Stress Disorder has been identified as one of the most commonly occurring mental illnesses in combatants. This study was conducted to determine the prevalence of Post-Traumatic Stress Disorder among soldiers who had undergone amputation of a lower or an upper limb or sustained a spinal cord injury in the battlefield, and to compare the prevalence among these categories. The research presented seeks to increase the awareness of this condition among those treating war casualties so that appropriate treatment choices could be made to address them. The study was carried out in 2009 at a rehabilitation centre for combatants of war. Data were collected from 96 male army veterans between the ages of 18-49 years using a pre-tested self-administered questionnaire based on the Diagnostic and Statistical Manual of Mental Disorders, the Impact of Event Scale and the PTSD symptom scale. Soldiers with injuries sustained at least four weeks prior to the study were selected by a convenience sampling technique. Soldiers with multiple injuries, head injuries or those diagnosed with psychiatric disorders were excluded. The results revealed that 41.7% of the study population was compatible with the diagnosis of Post-Traumatic Stress Disorder. Within the three groups, 42.5% of the lower limb amputees, 33.3% of the upper limb amputees and 45.7% of the participants with spinal cord injury had symptoms compatible with Post-Traumatic Stress Disorder. There was no difference between the prevalence among the different injury categories considered. This study highlights the need to pay more attention in providing psychological care as a part of the overall health management of injured combatants. Early preparation of soldiers for stressors of war and screening for and proper management of Post-Traumatic Stress Disorder will improve the overall outcome of rehabilitation.

Pollution of River Mahaweli and farmlands under irrigation by cadmium from agricultural inputs leading to a chronic renal failure epidemic among farmers in NCP, Sri Lanka.

Chronic renal failure (CRF) associated with elevated dietary cadmium (Cd) among farming communities in the irrigated agricultural area under the River Mahaweli diversion scheme has reached a significantly higher level of 9,000 patients. Cadmium, derived from contaminated phosphate fertilizer, in irrigation water finds its way into reservoirs, and finally to food, causing chronic renal failure among consumers. Water samples of River Mahaweli and its tributaries in the upper catchment were analyzed to assess the total cadmium contamination of river water and the possible source of cadmium. Except a single tributary (Ulapane Stream, 3.9 µg Cd/l), all other tested tributaries carried more than 5 µg Cd/l, the maximum concentration level accepted to be safe in drinking water. Seven medium-sized streams carrying surface runoff from tea estates had 5.1-10 µg Cd/l. Twenty larger tributaries (Oya), where the catchment is under vegetable and home garden cultivation, carried 10.1-15 µg Cd/l. Nine other major tributaries had extremely high levels of Cd, reaching 20 µg Cd/l. Using geographic information system (GIS), the area in the catchment of each tributary was studied. The specific cropping system in each watershed was determined. The total cadmium loading from each crop area was estimated using the rates and types of phosphate fertilizer used by the respective farmers and the amount of cadmium contained in each type of fertilizer used. Eppawala rock phosphate (ERP), which is mostly used in tea estates, caused least pollution. The amount of cadmium in tributaries had a significant positive correlation with the cadmium loading of the cropping system. Dimbula Tea Estate Stream had the lowest Cd loading (495.9 g/ha/year), compared with vegetable-growing areas in Uma Oya catchment with 50,852.5 g Cd/ha/year. Kendall's τ rank correlation value of total Cd loading from the catchment by phosphate fertilizer used in all crops in the catchment to the Cd content in the tributaries was +0.48. This indicated a major contribution by the cropping system in the upper catchment area of River Mahaweli to the eventual Cd pollution of river water. Low soil pH (4.5-5.2), higher organic matter content (2-3%), and 18-20 cmol/kg cation exchange capacity (CEC) in upcountry soil have a cumulative effect in the easy release of Cd from soil with the heavy surface runoff in the upcountry wet zone. In view of the existing water conveyance system from upcountry to reservoirs in North Central Province (NCP) through diversion of River Mahaweli, in addition to their own nonpoint pollution by triple superphosphate fertilizer (TSP), this demands a change in overall upper catchment management to minimize Cd pollution through agriculture inputs to prevent CRF due to elevated dietary cadmium among NCP farmers.

High efficacy of bolus methylprednisolone in severe leptospirosis: a descriptive study in Sri Lanka.

BACKGROUND: In 2008, an outbreak of leptospirosis caused high mortality in Sri Lanka. The General Hospital, Peradeniya recorded nine deaths in May, which prompted the medical staff to change the treatment protocol. Addition of intravenous methylprednisolone (MP) to the treatment regimen of severely ill patients was implemented on the basis of immune mediated pathogenesis of the disease to reduce mortality. METHODS: The day MP commenced (25 May 2008), the study period was divided into a 'pre-MP period' and an 'MP period'. A clinical score ranging from 0-6 was applied to assess the severity of the infection. A score ≥2 was considered severe. Thus, 62 patients received bolus MP 500 mg intravenously for 3 days, followed by oral 8 mg for 5 days (MP given). Ten patients to whom MP was withheld were included in the MP period severe group (n=72). The same score was applied to pre-MP periods and 60 cases were identified as the historical control group (pre-MP period severe). RESULTS: There were 78 and 149 cases of leptospirosis in the pre-MP period and MP period, respectively. Of these cases, 17 and 16 patients died, with case death rates of 21.8% and 10.7%, respectively; the difference was significant (p=0.025). The survival rate at score 4 in the MP period severe group was 100% (16 of 16), compared to 38% (5 of 13) in pre-MP period severe group; this difference was highly significant (p<0.001). Six patients who died despite MP therapy had a clinical score of 5 or 6; four were alcohol consumers, and two had heart disease and hypertension. CONCLUSION: MP may reduce mortality in patients with severe leptospirosis, except in cases with established multiple organ dysfunction and comorbidities. Therefore, early administration of MP seems advisable.

Remediation of cadmium contaminated irrigation and drinking water: a large scale approach.

Cadmium is one of the most troublesome toxic heavy metals. It accumulates in the water reservoirs and agricultural soil as a result of intensive use of Cd contaminated phosphate fertilizers, e.g. in agriculture in the North Central Province (NCP) of Sri Lanka. The hyper-accumulator Thlaspi caerulescens, accumulates up to 1000 ppm Cd in shoots without exhibiting toxicity symptoms. The storage rhizomes of year old Nelumbo nucifera (lotus) natural vegetation in water reservoirs in NCP accumulated 253+/-12 mg Cd/kg. Seedlings of lotus grown in 5% Hoagland's solution at 0.75, 1.0 and 1.25 ppm cadmium sulphate showed a significant increase in Cd removal of 0.0334-0.121 ppm/week. However the removal rate of Cd from water failed to increase any further at higher concentrations of Cd in water. The slow growth rate and low rate of phytoextraction demands a more effective but an affordable method of remediation in order to combat the prevailing elevated cadmium levels in NCP that causes chronic renal failure (CRF). We have developed a large scale filtering device using rice husk. We have achieved successful results in sequestering Cd using raw rice husk as well as amorphous silica derived from rice husk.

Chronic renal failure in Sri Lanka caused by elevated dietary cadmium: Trojan horse of the green revolution.

The endemic of chronic renal failure (CRF) emerged in 2002 in the farming provinces of Sri Lanka. An estimate of dietary cadmium intake was between 15 and 28 microg/kg body weight per week. The mean urinary cadmium in patients diagnosed with stage 5 kidney failure was 7.6 microg/g creatinine and 11.6 microg/g for asymptomatic persons. The agrochemical triple superphosphate (TSP) fertilizer containing 23.5-71.7 mg Cd/kg was the source of cadmium added to soils. Mean Cd content in cultivated vs. uncultivated soils in Anuradhapura district was 0.02 +/- 0.01 vs. 0.11 +/- 0.19 mg/kg while in Polonnaruwa district, it was 0.005 +/- 0.004 vs. 0.016 +/- 0.005 mg/kg. Prior to the Green Revolution, the amount of fertilizer used in rice cultivation in 1970 was 32,000 metric tons (Mts) rising to 74,000 Mts in 1975. Up to 68.9 Mts of Cd could have entered into the rice-cascade reservoir environment from TSP use since 1973. Diversion of the Mahaweli River in 1970-1980 further increased cadmium input. Cadmium transfer from Upper Mahaweli water to Polgolla was 72.13 kg/day. Cadmium content of the sediments from reservoirs collecting cadmium from irrigated TSP fertilized crop fields (rice and vegetables) was 1.8-2.4 mg/kg.

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).

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 0.03 to 0.06 mg/l. Sediment Cd concentration was 1.78-2.45 mg/kg. No arsenic (As) was detected. Cd content in lotus rhizomes was 253.82 mg/kg. The Provisional Tolerable Weekly Intake (PTWI) of Cd based on extreme exposure of rice is 8.702-15.927 microg/kg body weight (BW) for different age groups, 5-50 years. The PTWI of Cd due to extreme exposure of fish is 6.773-12.469 microg/kg BW. The PTWI on a rice staple with fish is 15.475-28.396 microg/kg BW. The mean urinary cadmium (UCd) concentration in CRF patients of age group 40-60 years was 7.58 microg Cd/g creatinine and in asymptomatic persons UCd was 11.62 microg 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.

Highly stable CuO incorporated TiO(2) catalyst for photo-catalytic hydrogen production from H(2)O.

A CuO incorporated TiO(2) catalyst was found to be an active photo-catalyst for the reduction of H(2)O under sacrificial conditions. The catalytic activity originates from the photogeneration of excited electrons in the conduction bands of both TiO(2) and CuO resulting in a build-up of excess electrons in the conduction band of CuO. Consequently, the accumulation of excess electrons in CuO causes a negative shift in the Fermi level of CuO. The efficient inter-particle charge transfer leads to a higher catalytic activity and the formation of highly reduced states of TiO(2)/CuO, which are stable even under oxygen saturated condition. Negative shift in the Fermi level of CuO of the catalyst TiO(2)/CuO gains the required over-voltage necessary for efficient water reduction reaction. The function of CuO is to help the charge separation and to act as a water reduction site. The amount of CuO and crystalline structure were found to be crucial for the catalytic activity and the optimum CuO loading was ca. approximately 5-10%(w/w).

Photocatalytic storing of O2 as H2O2 mediated by high surface area CuO. Evidence for a reductive-oxidative interfacial mechanism.

CuO powders with a high specific surface area are shown to be able to produce H(2)O(2) in aqueous solution under simulated light irradiation. The highest rate of peroxide production was observed under mild experimental conditions using O(2) and a large surface area photocatalyst CuO irradiated with a solar simulator having light intensities between 60 and 90 mW/cm(2). The CuO employed had a specific surface area (SSA) of 64.8-70.1 m(2)/g and was prepared in a tubular furnace by controlled thermal decomposition of precipitated copper oxalate. The CuO particles produced were 1 mum cubes with primary particles around 15 nm. No peroxide was produced under the same conditions with commercial CuO, with SSA 200 times lower. The CuO synthesized during this work was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), specific surface area [Brunauer-Emmett-Teller (BET)], porosity, and X-ray photoelectron spectroscopy (XPS). From XPS, it was observed that only Cu(II) was present in the unused and used CuO. This indicates that the redox transient species involving other Cu oxidation states disappear very fast during the reaction, regenerating Cu(II) during H(2)O(2) production. Diverse experiments provided some evidence for the possible interfacial reaction mechanism leading to H(2)O(2), following the initial step of O(2)(-)(.) formation on the CuO surface under irradiation with photons, with energies exceeding the band gap of CuO. A photocatalyzed degradation of a concentrated 4-chlorophenol (4-CP) solution was observed under solar-simulated light in the presence of CuO.

Composite tin and zinc oxide nanocrystalline particles for enhanced charge separation in sensitized degradation of dyes.

Composite ZnO/SnO2 catalyst has been studied for the sensitized degradation of dyes e.g. Eosin Y (2', 4', 5', 7'-tetrabromofluorescein disodium salt) in relation to efficient charge separation properties of the catalyst. Improved photocatalytic activity was observed in the case of ZnO/SnO2 composite catalyst compared to the catalytic activity of ZnO, SnO2 or TiO2 powder. The suppression of charge recombination in the composite ZnO/SnO2 catalyst led to higher catalytic activity for the degradation of Eosin Y. Degradation of Eosin follows concomitant formation of CO2 and formation of CO2 followed a pseudo-first-order rate. Photoelectrochemical cells constructed using SnO2, ZnO, ZnO/SnO2 sensitized with Eosin Y showed V(oc) of 175, 306, 512 mV/cm2 and I(sc) of 50, 70, 200 microA/cm2 respectively. A higher irreversible degradation of Eosin Y and higher V(oc) observed on composite ZnO/SnO2 than ZnO and SnO2 separately can be considered as a proof of enhanced charge separation of ZnO/SnO2 catalyst. Eosin Y showed a higher emission decreases on ZnO/SnO2 composite than on individual ZnO, SnO2 or TiO2 indicating dominance of the charge injection process. Photoinjected electrons are tunneled from ZnO to SnO2 particles accumulating injected electrons in the conduction bands allowing wider separation of excited carriers.

Interparticle Charge Transfer in Dye-Sensitized Films Composed of Two Kinds of Semiconductor Crystallites.

Interparticle charge transfer between different types of semiconductor crystallites in contact on band gap excitation or dye-sensitization is documented. The general consensus had been that electrons always transfer from particles of higher conduction band position to those with lower conduction band position. Observation on dye-sensitizated photoelectrochemical cells made from SnO(2)/ZnO films sensitized with different dyes suggests that the electron transfer could occur in either direction, that is from semiconductor of high band position to the semiconductor of the low band position or vice versa, depending on which surface adsorbs the dye more strongly. Copyright 2001 Academic Press.

Occurrence of aflatoxins in parboiled rice in Sri Lanka.

In Sri Lanka, rice is the main staple which is mostly processed into parboiled rice. The levels of aflatoxin B1 (AFB1) and aflatoxin G1 (AFG1) in parboiled and raw milled rice collected from major rice producing areas and rice consuming townships were estimated. In almost all the samples of parboiled rice examined, the AFB1 and AFG1 contents were significantly higher than in raw milled rice. The highest AFB1 content was 185 micrograms/kg and AFG1 content 963 micrograms/kg. These samples were collected from a major rice producing/milling district where the mean relative humidity is 78% and mean annual temperature 27 degrees C which is the highest amongst the rice growing areas in Sri Lanka. Raw rice was either free of aflatoxins or when toxins were detected, they occurred in less than 10% of the samples. The frequency of occurrence of surface fungal flora (Aspergillus/Penicillium) and aflatoxin content in market samples was closely related. Brownish or greenish moldly rice samples with fermented odour contained over 1000 micrograms/kg of AFB1.

Effect of parboiling and bran removal on aflatoxin levels in Sri Lankan rice.

Commercial parboiling of rice in Sri Lanka and many south Asian countries provides ideal conditions for the occurrence of aflatoxins because the rice is steeped (allowing fermentation) thus providing ideal conditions for growth of toxigenic Aspergillus species. However the traditional 'cottage' method of parboiling rice, which does not involve steeping, appears to reduce Aspergillus growth even after long storage periods. Preferential infection of parboiled rice by Aspergillus flavus was observed. Aflatoxin contents in inoculated rice produced by commercial parboiling (AFB1 60-92 mg/kg) were significantly higher than that in inoculated 'cottage' processed rice (AFB1 12-29 micrograms/kg). The steeping (precooking/soaking) process in commercial parboiling appears to increase the susceptibility of rice grains to fungal infection. Aflatoxin content in grains increased considerably with the increase in duration of soaking. However, the addition of 10 ppm calcium hypochlorite (bleach) to soaking water appreciably reduced A. flavus contamination and subsequent aflatoxin content in parboiled rice. No significant reduction in aflatoxin levels were observed after bran removal of contaminated rice.