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220 result(s) for "Jayasinghe, R"
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First genetic and morphological records of Balloon Alfonsin, Beryx mollis egg and larvae
Despite the importance of the commercially harvested benthopelagic fish Beryx mollis, little information is available on their adult phase and reproduction. This is likely due to the low abundance of this species compared to Beryx splendens and Beryx decadactylus as well as misidentification of Beryx spp. In this study, early life stages of B. mollis were found in the southwest region off Sri Lanka during a survey with research vessel Dr Fridtjof Nansen in 2018, coinciding with the southwest monsoon period. As morphological characteristics of eggs and larval stages of the three Beryx spp. are very similar, visual identification to differentiate to species level has always been challenging. Therefore, in this study, DNA barcoding was carried out targeting the mitochondrial COI gene. Molecular analysis confirmed that the collected egg and larvae belonged to the B. mollis species due to their high identity (>99%) with reference to previously submitted adult B. mollis sequences in the GenBank. Phylogenetic analysis showed a closer evolutionary relationship among B. mollis and B. splendens than with B. decadactylus. To the best of our knowledge this is the first genetic and morphological confirmation of B. mollis egg and larvae worldwide and suggests the southwest coastal area in Sri Lanka, in the north central Indian Ocean, as a potential spawning ground for this species.
Composition and diversity of larval fish in the Indian Ocean using morphological and molecular methods
Although vital in fisheries management, no comprehensive studies on ichthyoplankton have been conducted in Sri Lankan waters in the north central Indian Ocean hitherto. Hence, this study is the first detailed account of diversity and species composition of larval fish based on samples collected during the southwest monsoon in 2018. In total, 80 species belonging to 69 families were identified using morphological and molecular methods targeting the COI gene. The larval fish diversity varied significantly between regions: east (North East, Central East, and South East) and west (North West, South West, and South). In their larval stages, mesopelagic families were associated with the offshore waters whereas demersal and pelagic families were related with shelf regions in the South, South East, and Central East. The larvae of pelagic families are likely dispersed by the South Monsoon Current from the west to the east regions, while demersal fish seem to be confined to the same area as conspecific adults. The most abundant larval species observed were Selar crumenophthalmus, Cubiceps pauciradiatus, and Dipterygonotus balteatus. High abundances of several commercially important larval tuna species were found in the South East, Central East, and South regions indicating that these waters could be important nursery grounds. Furthermore, Callionymus simplicicornis was recorded for the first time in the Indian Ocean, and seven additional species were found new to Sri Lankan waters. The results from this study also highlight the importance of using combined morphological and molecular methods and the need for strengthening fish nucleotide databases in poorly studied areas of the Indian Ocean.
CTCF genetic alterations in endometrial carcinoma are pro-tumorigenic
CTCF is a haploinsufficient tumour suppressor gene with diverse normal functions in genome structure and gene regulation. However the mechanism by which CTCF haploinsufficiency contributes to cancer development is not well understood. CTCF is frequently mutated in endometrial cancer. Here we show that most CTCF mutations effectively result in CTCF haploinsufficiency through nonsense-mediated decay of mutant transcripts, or loss-of-function missense mutation. Conversely, we identified a recurrent CTCF mutation K365T, which alters a DNA binding residue, and acts as a gain-of-function mutation enhancing cell survival. CTCF genetic deletion occurs predominantly in poor prognosis serous subtype tumours, and this genetic deletion is associated with poor overall survival. In addition, we have shown that CTCF haploinsufficiency also occurs in poor prognosis endometrial clear cell carcinomas and has some association with endometrial cancer relapse and metastasis. Using shRNA targeting CTCF to recapitulate CTCF haploinsufficiency, we have identified a novel role for CTCF in the regulation of cellular polarity of endometrial glandular epithelium. Overall, we have identified two novel pro-tumorigenic roles (promoting cell survival and altering cell polarity) for genetic alterations of CTCF in endometrial cancer.
Impact of the Chemical Composition of Oil for Biodiesel Production to Reduce Environmental Pollution
The primary motivation for researching biofuels is to meet the world’s energy requirements. Demand for fossil fuels is rising significantly due to population expansion. Biodiesel is a promising renewable energy source that, if implemented effectively, has the potential to reduce the dependency on fossil fuels. Because biodiesel is a cleaner fuel that requires no engine modification, its implementation is not complicated. It can directly be used in diesel engines or as a blended diesel with fossil diesel. Seven different vegetable oils were utilized to replicate restaurant waste cooking oil in the laboratory to make biodiesel. The qualities of biodiesel produced were investigated and compared to determine how they vary depending on the chemical composition of the oil source. The physical appearance of biodiesel varies slightly depending on the oil source. Density, kinematic viscosity, flash point, and acid levels, on the other hand, are all within acceptable biodiesel criteria for all types of oil sources used.
A late presentation of acute iatrogenic aortic dissection following percutaneous coronary intervention: A case report
Acute iatrogenic aortic dissection following percutaneous coronary intervention is a rare but sinister cause of post-procedure morbidity and mortality. Delayed diagnosis increases the mortality significantly. We present a case of a 52-year-old male who presented with an iatrogenic aortic dissection following percutaneous coronary intervention for an inferior ST-elevation myocardial infarction. Although the diagnosis was initially missed by conventional imaging for a period of 5 months, it was later diagnosed assisted by cardiac computed tomography. The patient underwent aortic repair with a Dacron graft and had an uneventful recovery. The case highlights the importance of early diagnosis and selection of appropriate imaging for this rare but serious iatrogenic sequel following percutaneous coronary intervention to minimize morbidity.
Distribution and Abundance of the Blue Whale (Balaenoptera musculus indica) off Sri Lanka during the Southwest Monsoon 2018
Blue whales Balaenoptera musculus are the most abundant and widely distributed cetacean species in Sri Lankan waters. A vessel-based opportunistic line transect survey focusing on marine mammals was conducted in Sri Lankan waters between 24 June to 12 July 2018, while an ecosystem survey was performed by the R/V Dr. Fridtjof Nansen. The entire transect length was 2090 km within an area of 3895 km2. Overall, 72% (n = 57) of blue whale observations were group assemblages ranging between 1 and 5 individuals out of a total of 79 sightings. The largest aggregations of blue whales were recorded at the intersection of the submarine canyon off the coastline of Mirissa and busy shipping lanes between Dondra Head and Galle, where previous ship strikes were recorded. Overall, the average observed group size was 2.64 (CV, 12.34%; 95% CI, 2.07–3.38), the average group density was 0.0029 km−2 (CV, 35.96%; 95% CI, 0.00145–0.00610), and the total blue whale abundance within the survey area was 513 individuals (CV, 38.02%; 95% CI, 243–1083). These survey results fill vital knowledge gaps regarding the abundance and distribution of blue whales in Sri Lanka, which is essential for the establishment of management and conservation strategies.
Biodiesel-Alkaline Transesterification Process for Methyl Ester Production
The world needs to increase renewable and alternative fuel sources such as Biomass, Bioethanol, and Biodiesel to compete with fossil fuels. Biodiesel is an important renewable fuel source since it can be used in regular diesel vehicles without requiring engine modifications. Conventional biodiesel production takes around 90 min of reaction time. A longer reaction time is not suitable for commercial production. Furthermore, traditional products such as oil react with biodiesel methoxide to produce a maximum of 90% biodiesel yield. As the catalyst is not involved with the reaction, pure methanol and methoxide (methanol with KOH catalyst) are separately added to the system to enhance the pre-reaction step. By changing the methanol to methoxide ratio, biodiesel is produced, and yield is calculated. The highest yield, which is 95%, is obtained with a 5:15% methanol to methoxide ratio. The total reaction time with the new experimental procedure is only 20 min. That is a significant reduction by saving operating costs such as energy consumption. Produced biodiesel show similar properties to that of standard biodiesel.
DNA barcoding confirms the first record of a Desmodema polystictum (Ogilby, 1898) egg and all-time high adult catches in the Indian Ocean
The eggs of Polka-dot ribbonfish Desmodema polystictum have been recorded for the first time in the Indian Ocean. Although the only previous information on eggs from this species consists of line drawings from 1973 (Pacific Ocean), the identification was possible by combining morphological and molecular analyses. As far as we are aware, only few confirmed records of adult individuals have been previously reported from the Indian Ocean. We found eggs in the proximity of numerous adults (57 and 42 individuals at two stations) indicating that the Central Indian Ocean is potentially an important spawning ground of D. polystictum.
LENGTH-BASED STOCK ASSESSMENT OF OREOCHROMIS MOSSAMBICUS AND OREOCHROMIS NILOTICUS (ACTINOPTERYGII: PERCIFORMES: CICHLIDAE) IN MULTI-MESH GILLNET FISHERIES IN RESERVOIRS OF SRI LANKA
Gillnets of mesh sizes (6.9 to 12.7 cm) are used in individual boats in Sri Lankan reservoirs targeting exotic cichlid species, Oreochromis mossambicus (Peters, 1852) and Oreochromis niloticus (Linnaeus, 1758), which dominate the fisheries. The mesh composition of gillnets varies from boat to boat and from season to season making catch samples in individual boats are under the influence of different selectivity patterns. As such, the conventional procedure of correcting length frequency samples using the overall mean selectivity pattern in the fishery is not precise in estimating growth parameters. The presently reported study aimed at assessing cichlid stocks in three tropical reservoirs accounting for gillnet selectivity of individual sampled boats. Length frequency data obtained from each boat were corrected for the combined selectivity of the fleet of gillnets of different mesh sizes used in the boat during the sampling occasion. For predicting optimal fishing strategies using a yield-per-recruit approach, probabilities of capture determined from the array of fishing mortality in the length-structured virtual population analysis was incorporated. Length frequency data corrected for overall gillnet selectivity in sampled boats gave reliable estimates of von Bertalanffy growth parameters. Based on these estimates, mortality parameters were determined and the overall gear selection pattern was deduced from the array of fishing mortality in the length-structured virtual population analysis. Optimal fishing strategies were determined incorporating overall probabilities of capture in the relative yield-per-recruit (Y' × R-1) analysis. The overall gillnet selection pattern of a sampled boat offers a methodology for reliable estimation of growth parameters. Although both cichlid species are caught in gillnets simultaneously, Y' × R-1 analyses predicted increase of exploitation rate for one species while its decrease for the other species perhaps due to influence of other factors such as fish behaviour and fishers' choice of specific areas for fishing. This analysis provides a methodology of a more precise length-based stock assessment in future research.
Buzzing Wild Bee Visits Enhance Seed Set in Eggplant, Solanum melongena
Sixty percent of the angiosperms with poricidal anthers are buzz-pollinated by bees (Hymenoptera: Apoidea: Apiformes). Plant taxa with Solanum-type flowers have larger anthers and shorter filaments. Solanum melongena (Solanaceae) is more commonly and efficiently pollinated by buzz pollinators. The present study documented bees and their diurnal pattern of visitation to flowers, relationship between their handling time and flower age, and the effect of bee visits on fruit and seed set in S. melongena in two sites in Kandy District. Efficiency of buzz pollination over pollination in the absence of bees was determined using open buds and buds covered with pollinator exclusion bags. On average, 150 days were taken to complete the life cycle of Solanum melongena. Three buzzing bees and two nonbuzzing bees in site I and five buzzing bees and two nonbuzzing bees in site II were recorded. Handling time of Pachynomia sp. and Hoplonomia westwoodi indicates that bees spend more time at new flowers than at old flowers. Handling time is higher in the smaller bee, Pachynomia sp., than in the larger bee, H. westwoodi. Statistical data on pollinator exclusion experiment revealed that the fruit set and seed set of S. melongena are enhanced by buzz-pollinating bees.