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Elhassan N.,University of Khartoum | Gebremeskel E.I.,University of Khartoum | Gebremeskel E.I.,Eritrea Institute of Technology | Elnour M.A.,University of Khartoum | And 7 more authors.
PLoS ONE | Year: 2014

Human genetic variation particularly in Africa is still poorly understood. This is despite a consensus on the large African effective population size compared to populations from other continents. Based on sequencing of the mitochondrial Cytochrome C Oxidase subunit II (MT-CO2), and genome wide microsatellite data we observe evidence suggesting the effective size (Ne) of humans to be larger than the current estimates, with a foci of increased genetic diversity in east Africa, and a population size of east Africans being at least 2-6 fold larger than other populations. Both phylogenetic and network analysis indicate that east Africans possess more ancestral lineages in comparison to various continental populations placing them at the root of the human evolutionary tree. Our results also affirm east Africa as the likely spot from which migration towards Asia has taken place. The study reflects the spectacular level of sequence variation within east Africans in comparison to the global sample, and appeals for further studies that may contribute towards filling the existing gaps in the database. The implication of these data to current genomic research, as well as the need to carry out defined studies of human genetic variation that includes more African populations; particularly east Africans is paramount. © 2014 Elhassan et al. Source

Aseervatham G.S.B.,Bharathidasan University | Sivasudha T.,Bharathidasan University | Sasikumar J.M.,Eritrea Institute of Technology | Christabel P.H.,Karpagam University | And 2 more authors.
Journal of Physiology and Biochemistry | Year: 2014

Pouteria campechiana (Kunth) Baehni. is used as a remedy for coronary trouble, liver disorders, epilepsy, skin disease, and ulcer. Therefore, the present study aims to investigate the antioxidant and hepatoprotective effect of polyphenolic-rich P. campechiana fruit extract against acetaminophen- intoxicated rats. Total phenolic and flavonoid contents of egg fruit were estimated followed by the determination of antioxidant activities. Treatment with P. campechiana fruit extract effectively scavenged the free radicals in a concentration-dependent manner within the range of the given concentrations in all antioxidant models. The presence of polyphenolic compounds were confirmed by high-performance thin-layer chromatography (HPTLC). The animals were treated with acetaminophen (250 mg/kg body weight; p.o.) thrice at the interval of every 5 days after the administration of P. campechiana aqueous extract and silymarin (50 mg/kg). Acetaminophen treatment was found to trigger an oxidative stress in liver, leading to an increase of serum marker enzymes. However, treatment with P. campechiana fruit extract significantly reduced the elevated liver marker enzymes (aspartate transaminase, alanine transaminase, and alkaline phosphatase) and increased the antioxidant enzymes (viz., superoxide dismutase and catalase) and glutathione indicating the effect of the extract in restoring the normal functional ability of hepatocytes. These results strongly suggest that P. campechiana fruit extract has strong antioxidant and significant hepatoprotective effect against acetaminophen-induced hepatotoxicity. © 2013 University of Navarra. Source

Gebremeskel E.I.,University of Khartoum | Gebremeskel E.I.,Eritrea Institute of Technology | Ibrahim M.E.,University of Khartoum
European Journal of Human Genetics | Year: 2014

Archeological and paleontological evidences point to East Africa as the likely area of early evolution of modern humans. Genetic studies also indicate that populations from the region often contain, but not exclusively, representatives of the more basal clades of mitochondrial and Y-chromosome phylogenies. Most Y-chromosome haplogroup diversity in Africa, however, is present within macrohaplogroup E that seem to have appeared 21 000-32 000 YBP somewhere between the Red Sea and Lake Chad. The combined analysis of 17 bi-allelic markers in 1214 Y chromosomes together with cultural background of 49 populations displayed in various metrics: network, multidimensional scaling, principal component analysis and neighbor-joining plots, indicate a major contribution of East African populations to the foundation of the macrohaplogroup, suggesting a diversification that predates the appearance of some cultural traits and the subsequent expansion that is more associated with the cultural and linguistic diversity witnessed today. The proto-Afro-Asiatic group carrying the E-P2 mutation may have appeared at this point in time and subsequently gave rise to the different major population groups including current speakers of the Afro-Asiatic languages and pastoralist populations.European Journal of Human Genetics advance online publication, 26 March 2014; doi:10.1038/ejhg.2014.41. Source

Thompson D.A.,University of Aberdeen | Thompson D.A.,University of Leeds | Thompson D.A.,University of Bristol | Hammond J.O.S.,Imperial College London | And 8 more authors.
Geochemistry, Geophysics, Geosystems | Year: 2015

The mechanisms that drive the upwelling of chemical heterogeneity from the lower to upper mantle (e.g., thermal versus compositional buoyancy) are key to our understanding of whole mantle convective processes. We address these issues through a receiver function study on new seismic data from recent deployments located on the Afar Triple Junction, a location associated with deep mantle upwelling. The detailed images of upper mantle and mantle transition zone structure illuminate features that give insights into the nature of upwelling from the deep Earth. A seismic low-velocity layer directly above the mantle transition zone, interpreted as a stable melt layer, along with a prominent 520 km discontinuity suggest the presence of a hydrous upwelling. A relatively uniform transition zone thickness across the region suggests a weak thermal anomaly (<100 K) may be present and that upwelling must be at least partly driven by compositional buoyancy. The results suggest that the lower mantle is a source of volatile rich, chemically distinct upwellings that influence the structure of the upper mantle, and potentially the chemistry of surface lavas. © 2015. The Authors. Source

Sivakumar R.,Eritrea Institute of Technology
Iranian Journal of Radiation Research | Year: 2010

Background: Decay products of radon and thoron present in indoor environment are the most important sources of radiation from natural sources which affect human beings, since general public spend at lest 80% of their time in indoor. Materials and Methods: Air samples were collected for measuring the concentration of radon and thoron daughter products from various indoor environments during four different seasons of the year from the Gudalore taluk of Nilgiri Biosphere using high volume air sampler. The concentration of decay products of radon and thoron were estimated using an alpha counter. Results: Studies have revealed that the annual average potential alpha energy concentrations of radon and thoron progeny in dwellings of Gudalore were recorded as 3.54 and 2.65 mWL respectively. It was also observed that the potential alpha energy concentration (PAEC) values for radon progeny undergo dramatic change with the change of season perhaps due to different aerosol contents in the air. The maximum 222Rn (3.93 mWL) and 220Rn (3.10 mWL) progeny concentrations were observed during winter months and the minimum values (222Rn 3.14 mWL and 220Rn 2.20 mWL) were observed during summer. Conclusion: Studies have shown that the dwelling with mud wall registered high value of radon and thoron progenies (5.49 mWL and 3.88 mWL). While low values were observed in dwellings with vinyl floor. High concentrations of radon and thoron progeny were observed between 3.00 to 5.00 Hrs, while low values were observed at 14.00 hrs. Studies suggest that radiation emission from radon and thoron daughter in the study area were remained well below the recommended level. Source

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