Physical geodetic survey of the Nigeria landmass was undertaken with the aim of furnishing engineers and scientists with vital geodetic information which have not been adequately available but required for the development of a standard national economic framework. The basic data used for the study were the absolute gravity field values, and the recorded coordinates and elevations at the Primary Gravity Network of Nigeria (PGNN) base stations. The absolute gravity data were processed using the appropriate mathematical and computational procedures to deduce geodetic information which include geoid undulation, height above the geoid, deflections of the vertical, distance from the earth’s centre of mass to the reference ellipsoid and geoid, and the gravity potential value at the geoid. Comparison was also made between the WGS’84 and the geoid in the study area. Geoid undulations were found to range from 16.53 to 28.35 m and the deflections of the vertical ranged between 0.738685 to 10.28328 arc second. Height above the topography ranged from -16.38 m in Warri to +1257.13 in Jos. The distance from the earth’s centre of mass to the WGS’84 reference ellipsoidal surface was maximum at Oron (6377988.04 m) and least at Illela (6376941.31 m). Similarly, the distance from the earth’s centre of mass to the geoid was also maximum at Oron (6378008.39 m) and minimum in Illela (6376961.659 m). The interpolation of the distances from the earth’s centre of mass to the spheroidal surface at each base station gave the definition of the WGS’84 ellipsoid over the continental Nigeria landmass while the interpolation of the distances from the earth’s centre of mass to the geoidal surface gave the definition of the geoid over the continental Nigeria landmass. The average gravity potential at the geoid was evaluated as 62375050.41 m2s-2. The geoid over the continental Nigeria landmass was found to be comparably smooth as the WGS’84 ellipsoid over the region though they differ in terms of vertical separation. The quantitative difference in mGal corresponding to the vertical separation between the WGS’84 reference ellipsoid and the geoid was computed as 6.8042 mGal. The values of the deflections of the vertical at each station of the PGNN gave the angular correction to be applied when combining satellite-based ellipsoidal measurements and geoid-based physical geodetic measurement. Based on the significant range of the deflections of the vertical across the continental area of Nigeria, it was concluded that the physical structure of the lithosphere beneath the study area must be highly complex and heterogeneous.
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Comparative anti-diabetic study of the leaf, stem, and root bark extracts of Xylopia aethiopica (A. Dunal) RichAuthors: Famuyiwa, S. O.*, Ayoola M. D., Faloye, K. O. and Okewale, F. O.
A medicinal plant is any plant containing substances that are effective therapeutically or are precursors for drug manufacture in one or more of its organs. This work was a comparative study of the hypoglycaemic and hyperglycaemia-lowering activities of the methanol extracts of the leaf, stem, and root barks of Xylopia aethiopica used folklorically in the management of type 2 diabetes mellitus with the view of determining its most active morphological part. The pulverized leaves, stem and root barks of the plant were separately subjected to cold extraction using methanol to obtain leaf, stem and root barks extracts respectively. The hypoglycaemic and antihyperglycaemic effects of the extracts were carried out on normoglycaemic and glucose-induced hyperglycaemic rats, respectively at 100, 200 and 400 mg/kg using glibenclamide (5 mg/kg) as positive control. The most effective antihyperglycaemic doses of the extracts were used to determine its anti-diabetic activity on streptozotocin-induced diabetic rats. The results obtained from the study were subjected to analysis of variance (ANOVA), followed by Student–Newman-Keuls post hoc tests and p< 0.05 was considered significant. The results of the study showed that the root bark extract of X. aethiopica did not cause hypoglycaemia in rats at all the tested doses while hypoglycaemia was obtained at 400 mg/kg of the leaf and stem bark extracts. In the hyperglycaemia-lowering experiment using glucose loaded rats’ model, the leaf, stem and root bark extracts gave 10, 13, 10, 29; 35, 36, 38, 41 and 25, 27, 33, 44 % blood glucose levels reduction at 0.5, 1, 2 and 4 h, respectively which showed the stem bark as the most active plant part especially at 0.5-2 h. In the streptozotocin-induced hyperglycaemic rats experiment, the order of antihyperglycaemic effect of the morphological parts of X. aethiopica is, stem bark extract > leaf extract > root bark extract. It was concluded from the results obtained from the study that the stem bark extract of Xylopia aethiopica was the most active plant part both in glucose and streptozotocin-induced hyperglycaemia and it does not cause hypoglycaemia at low doses.
A study on the biocidal potentials of stem bark extract of Leucaena leucocephala (Lam.) on some selected bacterial strainsAuthors: Okanlawon, T. S.*, Ogundele, T.V., Omojoyegbe, R.T., Duduyemi, O. P and Agbaje, I. S.
Leucaena leucocephala is a fast-growing leguminous plant this is used in the treatment of intestinal diseases and as birth control. This work was geared toward investigating the phytochemical attributes and the antimicrobial actions of methanol and distilled water crude extracts from the stem bark of Leucaena leucocephala in the ratio of 3:2 on nineteen bacterial species. The antimicrobial activity of the plant extract was done with the use of the agar diffusion technique in line with the National Committee for Clinical Laboratory Standards. The extract was located to be energetic against sixteen bacterial traces at a concentration of 35 mg/mL except for Bacillus anthracis, Clostridium sporogenes, andPseudomonas fluorescens. The zones of inhibition exhibited by means of the extract towards the organisms ranged from 10.00 mm to 20.00 mm. The MIC exhibited by the extract ranged from 2.19 mg/ml to 8.75mg/ml while the MBC ranged from 4.38 mg/ml to 17.5 mg/ml. The effects of the extract on bacterial species were compared with the use of selected antibiotics such as streptomycin, and ampicillin. The phytochemical parts of the extract include tannins, glycosides, alkaloids, phenols, and terpenoids. Results from this research confirmed that the stem bark extract of Leucaena leucocephala exhibited antimicrobial activity against the selected bacteria and support the usefulness of this plant in folklore treatments.
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