University of Peradeniya

About: University of Peradeniya is a education organization based out in Kandy, Sri Lanka. It is known for research contribution in the topics: Population & Poison control. The organization has 5970 authors who have published 7388 publications receiving 197002 citations.

Anti-inflammatory effect of Ishige okamurae ethanolic extract via inhibition of NF-kappaB transcription factor in RAW 264.7 cells.

Abstract: Nowadays, much attention has been paid to the development of anti-inflammatory agents from marine natural resources. As a result of screening anti-inflammatory agents from marine algae using immunoassay, we found for the first time that ethanolic extract of Ishige okamurae (IO) classified into brown algae was effective in inhibiting the production of inflammatory mediators, such as tumor necrosis factor-alpha, interleukin-1beta, interleukin-6 and prostaglandin E(2), in RAW264.7 cells stimulated by lipopolysaccharide, compared with dexamethasone and aspirin used as positive control in this study. Moreover, transcriptional activation of NF-kappaB transcription factor that regulates the expression of these inflammatory mediators was also examined using reporter gene assay and western blot analysis. It was observed that IO extract exerted anti-inflammatory effect via inactivation of NF-kappaB transcription factor in macrophages. In addition, the expression and activity of matrix metalloproteinase-2 and 9 that play an important role in chronic inflammation were decreased in dose-dependent manner in the presence of IO extract in HT1080 cells. The above results suggest that IO extract can inhibit inflammation through inactivation of NF-kappaB transcription factor in macrophage.

Cyanobacteria: Pioneers of Planet Earth

Abstract: Cyanobacteria are among the earliest of inhabitants of Planet Earth and their existence can be traced back to 3.8 billion years. Their oxygenic photosynthesis led to the gradual conversion of the Earth‟s atmosphere from an anaerobic to an aerobic one. This change enabled the advent of aerobic organisms that eventually underwent rapid evolution and became the dominant, highly diverse members of the current global biodiversity. Cyanobacteria are ubiquitous in their distribution and are found in all the latitudes from Arctic and Anatarctic regions to the Tropical deserts perhaps reflecting their pioneering habitation of the primitive earth. They are also unique in their ability to simultaneously perform oxygenic photosynthesis and oxygen labile nitrogen fixation. Through these processes they make significant contributions to the Carbon and Nitrogen bio-geochemical cycles, particularly in the deep oceans. The ability of these organisms to fix N 2 either independently or in symbiosis with other organisms not only contributes to natural ecosystems but is applied in certain countries particularly for rice cultivation. Their ability to grow in highly polluted environments is also used in the treatment of sewage and industrial effluents. Cyanobacteria are the most efficient among all living organisms in the harvesting of solar energy and are currently looked at as highly attractive candidates for biofuel production. A few species are being used for the production of highly nutritive food supplements. On the negative side, some cyanobacteria form massive growths called „blooms‟ in water bodies and many of them produce toxins harmful to fish, digastric animals and are suspected to be responsible for certain human ailments. Having reviewed most of these aspects of cyanobacteria, it is concluded that knowledge on these little known organisms would be invaluable not only for students, scientists and environmentalists but also for industrialists and policy makers. Key words: cyanobacteria; blue-green algae; algal toxins; biofertilizers; biofuels DOI: http://dx.doi.org/10.4038/cjsbs.v40i2.3925 CJSBS 2011; 40(2): 71-88

Ergodic Capacity Comparison of Different Relay Precoding Schemes in Dual-Hop AF Systems With Co-Channel Interference

Abstract: In this paper, we analyze the ergodic capacity of a dual-hop amplify-and-forward relaying system, where the relay is equipped with multiple antennas and subject to co-channel interference and the additive white Gaussian noise. Specifically, we consider three heuristic precoding schemes, where the relay first applies the: 1) maximal-ratio combining (MRC); 2) zero-forcing (ZF); and 3) minimum mean-squared error (MMSE) principle to combine the signal from the source, and then steers the transformed signal toward the destination with the maximum ratio transmission (MRT) technique. For the MRC/MRT and MMSE/MRT schemes, we present new tight analytical upper and lower bounds for the ergodic capacity, while for the ZF/MRT scheme, we derive a new exact analytical ergodic capacity expression. Moreover, we make a comparison among all three schemes, and our results reveal that, in terms of the ergodic capacity performance, the MMSE/MRT scheme always has the best performance and the ZF/MRT scheme is slightly inferior, while the MRC/MRT scheme is always the worst one. Finally, the asymptotic behavior of ergodic capacity for the three proposed schemes are characterized in large N scenario, where N is the number of relay antennas. Our results reveal that, in the large N regime, both the ZF/MRT and MMSE/MRT schemes have perfect interference cancellation capability, which is not possible with the MRC/MRT scheme.

Mapping subnational HIV mortality in six Latin American countries with incomplete vital registration systems

Abstract: Background Human immunodeficiency virus (HIV) remains a public health priority in Latin America. While the burden of HIV is historically concentrated in urban areas and high-risk groups, subnational estimates that cover multiple countries and years are missing. This paucity is partially due to incomplete vital registration (VR) systems and statistical challenges related to estimating mortality rates in areas with low numbers of HIV deaths. In this analysis, we address this gap and provide novel estimates of the HIV mortality rate and the number of HIV deaths by age group, sex, and municipality in Brazil, Colombia, Costa Rica, Ecuador, Guatemala, and Mexico. Methods We performed an ecological study using VR data ranging from 2000 to 2017, dependent on individual country data availability. We modeled HIV mortality using a Bayesian spatially explicit mixed-effects regression model that incorporates prior information on VR completeness. We calibrated our results to the Global Burden of Disease Study 2017. Results All countries displayed over a 40-fold difference in HIV mortality between municipalities with the highest and lowest age-standardized HIV mortality rate in the last year of study for men, and over a 20-fold difference for women. Despite decreases in national HIV mortality in all countries—apart from Ecuador—across the period of study, we found broad variation in relative changes in HIV mortality at the municipality level and increasing relative inequality over time in all countries. In all six countries included in this analysis, 50% or more HIV deaths were concentrated in fewer than 10% of municipalities in the latest year of study. In addition, national age patterns reflected shifts in mortality to older age groups—the median age group among decedents ranged from 30 to 45 years of age at the municipality level in Brazil, Colombia, and Mexico in 2017. Conclusions Our subnational estimates of HIV mortality revealed significant spatial variation and diverging local trends in HIV mortality over time and by age. This analysis provides a framework for incorporating data and uncertainty from incomplete VR systems and can help guide more geographically precise public health intervention to support HIV-related care and reduce HIV-related deaths.