Cross River University of Technology

About: Cross River University of Technology is a education organization based out in Calabar, Nigeria. It is known for research contribution in the topics: Population & Exergy. The organization has 465 authors who have published 507 publications receiving 2705 citations.

Assessment of Interradiologist Agreement Regarding Mammographic Breast Density Classification Using the Fifth Edition of the BI-RADS Atlas

Abstract: Objective The objective of the present study was to assess interradiologist agreement regarding mammographic breast density assessment performed using the rating scale outlined in the fifth edition of the BI-RADS atlas of the American College of Radiology. Materials and methods Breast density assessments of 1000 cases were conducted by five radiologists from the same institution who together had recently undergone retraining in mammographic breast density classification based on the fifth edition of BI-RADS. The readers assigned breast density grades (A-D) on the basis of the BI-RADS classification scheme. Repeat assessment of 100 cases was performed by all readers 1 month after the initial assessment. A weighted kappa was used to calculate intrareader and interreader agreement. Results Intrareader agreement ranged from a kappa value of 0.86 (95% CI, 0.77-0.93) to 0.89 (95% CI, 0.81-0.95) on a four-category scale (categories A-D) and from 0.89 (95% CI, 0.86-0.92) to 0.94 (95% CI, 0.89-0.97) on a two-category scale (category A-B vs category C-D). Interreader agreement ranged from substantial (κ = 0.76; 95% CI, 0.73-0.78) to almost perfect (κ = 0.87; 95% CI, 0.86-0.89) on a four-category scale, and the overall weighted kappa value was substantial (0.79; 95% CI, 0.78-0.83). Interreader agreement on a two-category scale ranged from a kappa value of 0.85 (95% CI, 0.83-0.86) to 0.91 (95% CI, 0.90-0.92), and the overall weighted kappa was 0.88 (95% CI, 0.87-0.89). Conclusion Overall, with regard to mammographic breast density classification, radiologists had substantial interreader agreement when a four-category scale was used and almost perfect interreader agreement when a dichotomous scale was used.

Any l-state solutions of the Schrodinger equation interacting with Hellmann–Kratzer potential model

Abstract: The approximate analytical solutions of the radial Schrodinger equation have been obtained with a newly proposed potential called Hellmann–Kratzer potential. The potential is a superposition of Hellmann potential and modified Kratzer potential. The Hellmann–Kratzer potential actually comprises of three different potentials which include Yukawa potential, Coulomb potential and Kratzer potential. The aim of combining these potentials is to have a wide application. The energy eigenvalue and the corresponding wave function are calculated in a closed and compact form using the Nikiforov–Uvarov method. The energy equation for some potentials such as Kratzer, Hellmann, Yukawa and Coulomb potentials has also been obtained by varying some potential parameters. Our results excellently agree with the already existing literature. Some numerical results have been computed. We have plotted the behaviour of the energy eigenvalues with different potential parameters and also reported on the numerical result.

Diet, size and reproductive biology of the silver catfish, Chrysichthys nigrodigitatus (Siluformes: Bagridae) in the Cross River, Nigeria

Abstract: The silver catfish, Chrysichthys nigrodigitatus (Lacepede: 1803) is a highly valued food-fish included among the dominant commercial catches exploited in major rivers of Africa. To provide useful biological data for management, samples were collected monthly between January (2005) and December (2007) in three zones: I: Upper Cross River (grassland), II: Middle Cross River (mixed forest and grassland), and III: Lower Cross River (rainforest)) along 200 km length of the Cross River, Nigeria. Data from 1 248 specimens were processed using: allometric coefficient (b), gonado-somatic index, Fulton's condition factor and diversity indices. Male dominance was observed in all populations; C. nigrodigitatus reached maturity at 11.5cm (male) and 16.7cm (female) total length. Gonado-somatic index was higher for females with a peak in the early rains. The breeding period was between April and August with mean fecundity ranging between 4522 ±1924 eggs and 20321 ± 5543 eggs. This was directly related to total length and weight by the regression models: F = 2365.88 + 560.22 log L and F = 5025.81 +56.34 log W respectively. Exponential equations for length-weight relationships were Wt=- 1.997 Lt 2.206 (Zone I), W = -2.831 Lt 3.040 (Zone II) and Wt= -2.245 Lt 2.995 (Zone III). The mean allometric coef- ficient (b) showed significant departure from cubic value (negative allometry) for Zone I while Zones II and III showed no difference, indicating isometry. Dominant items in the diet were fish and fish parts constituting 21.6% with Food Richness and Gut Repletion Index of 18 and 100% respectively, in all zones. Diet Breadth of 0.802 (Zone I), 0.922 (Zone II) and 0.910 (Zone III) indicate a high trophic flexibility that enables switching from one diet to another according to availability. Mean condition factor for males varied from 0.718 ±0.117 minimum in Zone I to 0.996 ±0.062 maximum in Zone III. Forest inland wetlands (Zone II and III) of Cross River provided better condition for C. nigrodigitatus. Rev. Biol. Trop. 56 (4): 1785-1799. Epub 2008 December 12.

The biomedical significance of the phytochemical, proximate and mineral compositions of the leaf, stem bark and root of Jatropha curcas

Abstract: Objective To analyse the phytochemical contents of leaf, stem bark and root of Jatropha curcas (J. curcas) in four solvent extracts and their proximate and mineral compositions. Methods Standard analytical procedures were used for the determination of phytochemicals, proximate and mineral compositions of the leaf, stem bark and root extracts of J. curcas. Results Results of the analysis showed the presence of polyphenols, flavonoids, alkaloids, cardiac glycosides, coumarins, saponins, terpenoids, steroids, triterpenoid saponins, carotenoids, phlobatannins and tannins in the leaf, stem bark and root of all the solvent extracts. Flavonoids were present in the highest amount in the ethyl acetate extracts of the leaf (7.35% ± 0.02%), stem bark (4.12% ± 0.01%) and root (3.35% ± 0.02%) followed by polyphenols in the methanol extracts of leaf (4.62% ± 0.02%), stem bark (2.77% ± 0.05%) and root (2.49% ± 0.02%). Poly-acetylated compounds were absent in all the solvent extracts of the leaf, stem bark and root. However, some anti-nutritional agents such as oxalates, phytates and cyanates were present in all the solvent extracts of the leaf, stem bark and root except the ethyl acetate. Phytates were high in the aqueous solvent of the leaf (6.12% ± 0.00%) but low in the stem bark (1.00% ± 0.05%) and root (0.89% ± 0.03%). Proximate composition showed appreciable amounts of total carbohydrate (36.33% ± 0.72%), crude protein (26.00% ± 0.47%) and reducing sugars (5.87% ± 0.14%) in the leaf, while crude fat was more in the stem bark (16.70% ± 0.30%). There was corresponding substantial energy in the leaf [(1514.77 ± 20.87) kJ/100 g] and stem bark [(907.00 ± 8.52) kJ/100 g]. Moisture and ash contents of the leaf, stem bark and root were within acceptable limits for the use in drugs formulation. The mineral composition showed substantial amounts of important elements such as Fe, Ca, Na, Mg and Zn. Others were P, K and Se. Conclusions The outcome of this study suggests that the leaf, stem bark and root of J. curcas have very good medicinal potentials, meet the standard requirements for drug formulation and serve as good sources of energy and nutrients except for the presence of some anti-nutritional elements predominant in the leaf.

Toxicity of Lead to Freshwater Invertebrates (Water fleas; Daphnia magna and Cyclop sp ) in Fish Ponds in a Tropical Floodplain

Abstract: Acute toxicity of Pb to the water flea; (Daphnia sp) and Copepod, (Cyclop sp) both important component of zooplankton diet of fish was determined by static assay. A positive relationship between percentage mortality and exposure concentration was found in all tests. Mean 24-h LC50, 48-h LC50 and 96-h LC50 values were 2.51 ± 0.0.04 mg l−1, 1.88 ± 0.06 mg l−1 and 1.65 ± 0.19 mg l−1 for Daphnia spp and 3.11 ± 0.03 mg l−1, 2.97 ± 0.05 mg l−1 and 2.61 ± 0.09 mg l−1 for Cyclop spp, respectively. For all tested species did the LC50 values decrease with time; the decrease was more marked for Daphnia spp. Observed symptoms include spiral movement followed by change of body colour to white and rapid disintegration of the skin. The Daphnia spp. appear to be more sensitive to Pb poison than Cyclop spp. The results showed that concentrations of Lead (Pb) in excess of 0.19 mg l−1 and 0.30 mg l−1 can be potentially harmful to Daphnia magna and Cyclop spp respectively.