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- ItemMechanistic studies on Diels-Alder [4þ2] cycloaddition reactions ofa,b-substituted cyclobutenones: Role of substituents in regio- andstereoselectivity(Elsevier Ltd., 216-11-03) Fosu, Evans; Tia, Richard; Adei, EvansDiels-Alder reactions of substituted cyclobutenones with 6-methoxy-1-vinyl-3,4-dihydronaphthaleneand methoxy-substituted-1,3-butadiene have been studied with DFT. In the reactions of 6-methoxy-1-vinyl-3,4-dihydronaphthalene with cyclobutenone anda-bromocyclobutenone, the formation of themetaandorthoisomers have the same barriers, indicating that the two isomers might be formed in equalproportions, contrary to earlier reports. The regiochemistry of the reaction is mainly controlled by theketone functionality at C1 on the dienophiles. In the reactions of methoxy-substituted-1,3-butadienewith cyclobutenone anda,b-substituted cyclobutenones theortho/endoandpara/endostereo-isomericpathways are the most favorable pathways, changing toexoselectivity when OH, Br, CH3are placedon theb-carbon of the cyclobutenone, but still withorthoandpararegioselectivity. The stereoselectivityis independent of the bulkiness of substituents. The stability of substituted cycloadducts are lowercompared to unsubstituted adducts and this explains why thea-cyanoketones anda-bromoketoneproducts readily undergotrans-methylation and angular-alkylation as electrophiles.
- ItemOn-farm evaluation of biological nitrogen fixation potential and grain yield of Lablab and two soybean varieties in the northern Guinea savanna of Nigeria(Springer, 2005) Okogun J.A.; Sanginga N.; Abaidoo R. C; Dashiell K.E.; Diels J.; 0000-0002-1235-2252Several legumes with high biological nitrogen fixation (BNF) potentials have been studied in on-station trials. The processes involved in BNF and the benefits of these species to crop production need to be evaluated using farmers’ management practices in farmers’ fields. An on-farm trial with 20 farmers was conducted in the northern Guinea savanna (NGS) of Nigeria. The aims were to evaluate the BNF potentials of an improved soybean variety (TGx 1448-2E) and a local variety (Samsoy-2) when inoculated with Bradyrhizobium strains, and of Lablab in farmer-managed and researcher-managed soybean-maize and Lablab-maize crop rotation systems. The level of soil P was generally low with more than 50% of the fields having less than the critical P level. The plant available P content was statistically significantly (P = 0.05) correlated with P in grain (r = 0.60), P in the shoot (r = 0.68), grain yield (r = 0.40) and nodule weight (r = 0.35). Variations in plant parameters (nodulation, shoot dry matter, percentage nitrogen derived from the air [%Ndfa], grain yield, and nutrient uptake) among and within farmers’ fields were attributed to differences in soil fertility and crop management. About 60% of the fields were mod erately fertile, sufficient to support legume establishment, while about 30% of the farmers’ fields had a low fertility level. For farmers in the study area to benefit from the BNF potentials of the legumes, an external P fertilizer input was necessary as well as suitable crop management practices because all parameters mea sured in the researcher-managed plots were higher than in the farmer-managed plots.
- ItemMINERAL NUTRIENT UPTAKE AND REMOVAL BY COWPEA, SOYBEAN AND MAIZE CULTIVARS IN WEST AFRICA, AND IMPLICATIONS FOR CARBON CYCLE EFFECTS ON SOIL ACIDIFICATION(Cambridge University Press, 2006) RANDALL P. J; Abaidoo R. C; HOCKING P. J.; SANGINGA N.A field study of cowpea, soybean and maize was made at Ibadan, Nigeria, to determine the uptake of mineral nutrients and quantities removed in crop residues and seed. Concentrations of N, the major cations (K, Ca, Mg and Na) and major anions (P, S and Cl), and the micronutrients (Fe, Mn, Zn and Cu) were determined in shoots harvested at flowering and maturity. Concentrations of excess cations in shoots at flowering were 135 cmolc kg−1 for soybean, 158 cmolc kg−1 for cowpea and 58 cmolc kg−1 for maize. In crop residues and seed at maturity, the values decreased to 75 and 56 cmolc kg−1 respectively for soybean, 68 and 27 cmolc kg−1 respectively for cowpea, and 52 and 10 cmolc kg−1 respectively for maize. Nutrient and excess cation concentrations were also measured in 13 soybean and eight cowpea lines grown in replicated field trials at Fashola in the derived savanna zone and Shika in the northern Guinea savanna zone of Nigeria to assess the variation within these species. Maize, mucuna and lablab were included at these sites. The results are discussed in the context of soil nutrient depletion due to removal of nutrient elements in harvested seed and stover. The contribution of seed and stover removal to the proton (H+) budget and acidification of the soil is also discussed. It is estimated that the quantity of lime required to neutralize the acidity resulting from the removal of 1 t seed is 28 kg for soybean, 14 kg for cowpea and 5 kg for maize. The corresponding values for stover were soybean 35, cowpea 24 and maize 26 kg lime t−1 stover. Given the soil pH buffer capacity at the Ibadan site for the surface 16 cm, the yields obtained and assuming that seed and crop residues are removed, carbon cycle acidification would lead to a fall of 1 pH unit after 75 crops for soybean, 114 crops for cowpea and 68 crops for maize. The inclusion of legumes in cropping systems to increase N supply, and the use of P fertilizer to maximize N-fixation by legumes will raise production, but will inevitably accelerate removal of alkalinity and nutrients in harvested products, and the consequent decline in soil fertility. The data presented in this paper can be used in estimating the lime and fertilizer nutrients needed to maintain soil fertility and sustain yields
- ItemGenotypic variation for phosphorus uptake and dinitrogen fixation in cowpea on low-phosphorus soils of southern Cameroon(Wiley, 2006) Jemo Martin; Abaidoo R. C; Nolte Christian; Horst Walter J.In cowpea, efficient N2-fixing genotypes are being selected to promote sustainable cropping systems in southern Came roon (SC). However, N2 fixation and growth of these geno types are largely hampered by low levels of soil plant-avail able P. To evaluate the genotypic variation in N2 fixation and P uptake among cowpea (Vigna unguiculata L.) genotypes, field experiments were conducted over two years on two acid soils low in available P. The experiments were laid out in a split-block design with four replications on typic (TK) and rhodic (RK) Kandiudult soils with seven cowpea genotypes. Phosphorus (P) fertilizers were applied on the main plots with 0 kg P, 30 kg P ha–1 as triple superphosphate (TSP) and 90 kg P ha–1 as Togo phosphate rock (PR). Nodule dry matter(DM), shoot DM, grain yield, and P uptake of cowpea significantly varied with site, P application, and genotype (p < 0.05). The N2 fixation of the cowpea genotypes ranged from 29 to 51 kg N ha–1 on both TK and RK soils and was sig nificantly increased with P application. Significant genotypic variations in N2 fixation were observed with superior ability of the genotypes IT89KD-391 and IT90K-59 to fix N2. The harvest index (HI) did not significantly differ between soils and P application levels (p > 0.05). Four genotypes were selected to investigate root mechanisms responsible for effi cient P acquisition in pot experiments. The results suggest that a better root infection by arbuscular mycorrhizal fungi (AMF) in genotype IT90K-59 and root morphological and phy siological characteristics in IT89KD-391 were the most impor tant factors for inc
- ItemIrrigated urban vegetable production in Ghana: microbiological contamination in farms and markets and associated consumer risk groups(IWA Publishing, 2007) Amoah P.; Drechsel P.; Abaidoo R. C; Henseler M.Ghana is a typical low-income sub-Saharan African country facing significant sanitation challenges. In Ghana, fresh salads are not part of the normal diet, but have become a common supplement to urban fast food served in streets, canteens and restaurants. In Accra, about 200 000 people consume from such supplements every day. The figure also describes the size of the risk group from contamination, which comprises all income classes including the poor and children. The purpose of this study was to investigate widespread water pollution in urban and peri-urban areas, where 95% of the lettuce consumed in the city is produced. Over 12 months (April 2004– June 2005), lettuce samples from the same production sites in two cities were followed and analyzed along the “farm to fork” pathway for total and faecal coliform (FC) and helminth egg numbers. Questionnaire surveys were conducted among producers, sellers and consumers to quantify lettuce flows to the final risk group. The study identified the farm as the main point of lettuce contamination. Besides the irrigation water, contamination was also attributed to manure application and already contaminated soil. Despite poor sanitary conditions in markets, post-harvest handling and marketing did not further increase the farm-gate contamination levels. To reduce the health risk associated with the consumption of contaminated lettuce; safer farming and irrigation practices are required while the remaining risk could best be addressed where lettuce is prepared for consumption.
- ItemEffect of soaking, autoclaving and repeated boiling on oligosaccharides in cowpea.(Nigerian Food Journal, 2007) Agbenorhevi, Jacob K.; Oduro, Ibok N.; Ellis, William Otoo; Abodakpi, V. D.; Eleblu, S. E.; 0000-0002-8516-7656; 0000-0003-3731-2684Oligosaccharidesin beans are known to be the major cause of flatulence associated with beans consumption. The effects of soaking, autoclaving and repeated boiling on the oligosaccharide levels in ten cowpea varieties were studied. The oligosaccharides were extracted in 70% aqueous ethanol and separated by thin layer chromatography(TLC) method. The quantitation was done using the spectrophotometer. The results showed that the total oligosaccharide content varies among the cowpea varieties; 0.197 - 0.918g/100g. IT93K-596 had the lowest oligosaccharide content (0.197g/100g) and IT94K-410-2 the highest (0.918g/100g). Autoclaving, soaking and repeated boiling had a reductive effect on the total oligosaccharides content in the cowpeas used.Autoclaving reduced raffinose level by 23-68%,stachyose level by 12-81% and total oligosaccharides level by 23- 74%. Repeated boiling reduced the raffinose level by 23-61%; stachyose, 20-58% and total oligosaccharide by 15-55%. The loss of raffinose and stachyose after soaking ranged from 18.2-53.6% and 20.4-75.1% respectively and the total oligosaccharide loss, 25.1-63.9%. These treatments are therefore recommended for oligosaccharide reduction in cowpeas however their efficiency is variety dependent. These processing methods promise improved utilization or consumption of cowpea in the sense of curbing flatulence associated with beans meal.
- ItemBarriers to Condom use among the Youth in a Municipal Town in Ghana(Journal of the Ghana Science Association, 2007-01-09) Abdul-Kabir, M.; Otupiri, Easmon; Opare, D.; 0000-0001-8986-1648Condom-use has been identified as one way to reduce the spread of HIV/AIDS but the prevalence of consistent condom-use remains low, especially in West Africa. An analytical cross-sectional survey was conducted in the Sunyani Municipality in the Brong-Ahafo to identify barriers to condom-use among young people. The association between study variables were tested and quantified. Two hundred and twenty (220) sexually active individuals aged 15-24 years were interviewed using a questionnaire to elicit information on their sexual history and behaviour, condom-use history and the extent to which certain behavoiurs and experiences impede condom-use in their sexual relationships. Condom-use at last intercourse was reported by only 37.5% of males and 38.9% of females (p<0.832). Age, education and marital status were significantly associated with condom-use (p<0.001, p<0.005, p<0.030). Partner trust, non-availability of condoms, not achieving the desired sexual satisfaction and embarrassment of condom purchase were the main barriers to condom-use. Prevention strategies based on perceived severity or adequate knowledge about HIV/AIDS may not be sufficient to induce condom-use. Reproductive health services to young people should emphasize personal vulnerability to HIV and other sexually transmitted infections to encourage condom-use among sexually active young people.
- ItemGenetic variation and genotype × environment interaction in yams (Dioscorea spp.) for root colonization by arbuscular mycorrhiza(Journal of Food, Agriculture & Environment, 2008) Dare M. Olajire; Abaidoo R. C; Fagbola Olajire; Asiedu RobertRoot colonization by arbuscular mycorrhiza (AM) enhances nutrient acquisition by plants and could benefit the production of yam (Dioscorea spp.). The variation in AM colonization in yam genotypes was evaluated in two experiments at four locations (Ibadan, Onne, Abuja and Ubiaja) in different agroecologies of Nigeria in 2004 and 2005. Twenty-seven genotypes of D. rotundata and 28 of D. alata were investigated in a randomized complete block design with three replicates. Arbuscular mycorrhizal fungi colonized all yam genotypes. Root length colonization ranged from 24 to 95% in D. rotundata and from 21 to 95% in D. alata. Colonization was observed to be high in locations with lower soil available P but was not precluded by relatively high soil acidity. Highly significant (P< 0.001) effects were observed in D. rotundata for genotype and location, as well as genotype × location, location × year and in D. alata for genotype, location and year. The location × genotype × year interaction was significant (P < 0.05) in both experiments. The broad sense heritability estimates for AM colonization were 0.60 in D. rotundata and 0.87 in D. alata. Further analysis of genotype × environment interactions using a GGE biplot for the two-year data showed that the most stable genotypes for AM colonization across locations were TDr 93-32 (D. rotundata) and TDa 98/01183 (D. alata). The highest percentage AM colonization mean were found in TDr 93-32 (D. rotundata) and TDa 01/00204 in (D. alata). Generally, the highest mean colonization values were obtained at Abuja and Ubiaja. The results of this study reveal that AM colonization in yam is host-dependent and influenced by the environment.
- ItemGenotype effects of cowpea and soybean on nodulation, N2-fixation and N-balance in the Northern Guinea Savanna of Nigeria(Journal of Agronomy, 2008) Yusuf, A. A.; Abaidoo, R. C.; Iwuafor, E.N.O.; Olufajo, O. O.This study was designed to evaluate N2-fixation and N balance of improved cowpea and soybean genotypes in the NGS of Nigeria. Field experiments were conducted in 2003 and 2004 to assess .........
- ItemDietary intake of organophosphorus pesticide residues through vegetables from Kumasi, Ghana(Food and Chemical Toxicology, 2008-09-22) Darko, Godfred; Osei, Akoto; 0000-0001-7157-646XContamination and health risk hazards of organophosphorus pesticides residues in vegetables were studied. Ethyl-chlorpyrifos, observed at an average level of 0.211 ± 0.010 mg kg1 in 42% of tomato, 0.096 ± 0.035 mg kg1 in 10% of eggplant and 0.021 ± 0.013 mg kg1 in 16% of pepper was below the 0.5 mg kg1 MRL. Dichlorvos was the most frequently detected residue in all the samples analyzed. Levels of malathion in tomatoes (0.120 ± 0.101 mg kg1) and pepper (0.143 ± 0.042 mg kg1) exceeded the MRL of 0.1 mg kg1. Health risks were found to be associated with methyl-chlorpyrifos, ethyl-chlorpyrifos, and omethioate in tomatoes and methyl-chlorpyrifos, ethyl-chlorpyrifos, dichlorvos, monocrotophos and omethioate in eggplant. Routine monitoring of these pollutants in food items is required to prevent, control and reduce the pollution and to minimize health risks.
- ItemRheological and microstructural investigation of oat -glucan isolates varying in molecular weight(International Journal of Biological Macromolecules, 2011) Agbenorhevi, Jacob K.; Kontogiorgos, Vassilis; Kirby, Andrew R.; Morris, Victor J.; Tosh, Susan M.; 0000-0002-8516-7656The rheological properties and microstructure of aqueous oat -glucan solutions varying in molecular weight were investigated. The structural features and molecular weights (MW) were characterized by 13C NMR spectroscopy and high performance size-exclusion chromatography (HPSEC), respectively. The microstructure of the -glucans dispersions was also examined by atomic force microscopy (AFM). The samples with -glucan content between 78 and 86% on a dry weight basis had MW, intrinsic viscosity ([ ]) and critical concentration (c*) in the range of 142–2800 × 103 g/mol, 1.7–7.2 dl/g and 0.25–1.10 g/dl, respectively. The flow and viscoelastic behaviour was highly dependent on MW and on the concentration of the -glucans dispersions. Pseudoplastic behaviour was exhibited at high concentrations and Newtonian behaviour was evident at low concentrations. At the same concentration,the viscosity was higher for higher MW samples. The Cox–Merz rule was applicable for the lower molecular weight samples at higher concentrations whereas the high molecular weight sample deviated at concentrations greater than 1.0%, w/v. The mechanical spectra with variation of both MW and concentration were typical of entangled biopolymer solutions. AFM images revealed the formation of clusters or aggregates linked via individual polymer chains scattered heterogeneously throughout the system. The aggregate size increased with the molecular weight of the samples investigated and has been linked to the rheological behaviour of the samples
- ItemMycolactone Diffuses into the Peripheral Blood of Buruli Ulcer Patients - Implications for Diagnosis and Disease Monitoring(PLoS Neglected Tropical Diseases, 2011-07-19) Sarfo, Fred Stephen; Chevalier, Fabien Le; Aka, N’Guetta; Phillips, Richard Odame; Amoako, Yaw; et. alBackground: Mycobacterium ulcerans, the causative agent of Buruli ulcer (BU), is unique among human pathogens in its capacity to produce a polyketide-derived macrolide called mycolactone, making this molecule an attractive candidate target for diagnosis and disease monitoring. Whether mycolactone diffuses from ulcerated lesions in clinically accessible samples and is modulated by antibiotic therapy remained to be established. Methodology/Principal Finding: Peripheral blood and ulcer exudates were sampled from patients at various stages of antibiotic therapy in Ghana and Ivory Coast. Total lipids were extracted from serum, white cell pellets and ulcer exudates with organic solvents. The presence of mycolactone in these extracts was then analyzed by a recently published, fieldfriendly method using thin layer chromatography and fluorescence detection. This approach did not allow us to detect mycolactone accurately, because of a high background due to co-extracted human lipids. We thus used a previously established approach based on high performance liquid chromatography coupled to mass spectrometry. By this means, we could identify structurally intact mycolactone in ulcer exudates and serum of patients, and evaluate the impact of antibiotic treatment on the concentration of mycolactone. Conclusions/Significance: Our study provides the proof of concept that assays based on mycolactone detection in serum and ulcer exudates can form the basis of BU diagnostic tests. However, the identification of mycolactone required a technology that is not compatible with field conditions and point-of-care assays for mycolactone detection remain to be worked out. Notably, we found mycolactone in ulcer exudates harvested at the end of antibiotic therapy, suggesting that the toxin is eliminated by BU patients at a slow rate. Our results also indicated that mycolactone titres in the serum may reflect a positive response to antibiotics, a possibility that it will be interesting to examine further through longitudinal studies.
- ItemAssessing and Strengthening African Universities’ Capacity for Doctoral Programmes(PLoS Medicine, 2011-09) Bates, Imelda; Phillips, Richard Odame; Martin-Peprah, Ruby; Kibiki, Gibson; Gaye, Oumar; et.alUniversities can make a major contribution to good policy-making by generating nationally relevant evidence, but little is known about how to strategically support universities in poorer countries to train and nurture sufficient internationally competitive researchers. N It is difficult for universities to develop a coherent strategy to identify and remedy deficiencies in their doctoral training programmes because there is currently no single process that can be used to evaluate all the components needed to make these programmes successful. N We have developed an evidence-based process for evaluating doctoral programmes from multiple perspectives that comprises an interview guide and a list of corroborating documents and facilities; we refined and validated this process by testing it in five diverse African universities. N The strategy and priority list that emerged from the evaluation process facilitated ‘‘buy-in’’ from internal and external agencies and enabled each university to lead the development, implementation, and monitoring of their own strategy for remedying doctoral programme deficiencies.
- ItemInvestigation into the Total Phenols and Antioxidant Activity during Storage of Fruit Smoothies(Journal of Food Science and Engineering, 2012) Agbenorhevi, Jacob K.; Marshall, Lisa J.; 0000-0002-8516-7656; 0000-0001-6057-5592In this study, the total phenols (TP) and antioxidant activity of three different fruit smoothies (Blackberries, Raspberry and Boysenberry (BRAB), Mango and Passion fruits (MAP) and Blackcurrant, Acerola cherries and Rosehips (BACAR)) were determined during storage by Folin-Ciocalteu and ferric reducing antioxidant power (FRAP) assays respectively. TP ranged from 1,943 to 2,692 mg L-1 gallic acid equivalent whereas FRAP from 43,217 to 126,125 µmol L-1 Trolox equivalent for the three smoothies on opening. BACAR had the highest TP and antioxidant activity. The smoothies showed significant decrease (P < 0.05) in TP during storage. The decrease in antioxidant activity was significant (P < 0.05) for BRAB and MAP only. However, the study revealed that the smoothies had high antioxidant activity even during shelf-life at 4 °C which implies that consumption of smoothies may give considerable antioxidant benefits. Correlation between TP and antioxidant activity was strong and highly significant (r = 0.890, P < 0.0001).
- ItemContraceptive Characteristics of Women Living with HIV in the Kumasi Metropolis, Ghana(International Journal of MCH and AIDS, 2013) Gyimah, Akosua A.; Nakua, Emmauel K.; Owusu-Dabo, Ellis; Otupiri, Easmon; 0000-0001-8986-1648Objectives: Contraceptive use among women living with HIV is important to prevent the transmission of the infection to their partners, prevent unintended pregnancies and prevent the mother-to-child transmission of the infection. The study sought to determine the contraceptive characteristics of women living with HIV in the Kumasi metropolis. Methods: A cross-sectional study was conducted from July to August 2012 at two HIV/AIDS clinics in the Kumasi Metropolis in the Ashanti Region, Ghana. Interviewer- administered questionnaires were used to collect data from two hundred and ninety five women. Data from one hundred and eighty three women living with HIV and who were sexually active were analyzed. Factors associated with contraceptive use were examined using logistic regression. Results: The overall contraceptive use was high; 84.7% were using a modern contraceptive method. The male condom was the commonest contraceptive method (77.0%) used and this was the main contraceptive method promoted at the HIV/AIDS clinic. Dual method usage was low (4.4%). Multivariate analysis showed that the significant predictor of contraceptive use was HIV status disclosure to partner (AOR = 0.25; 95% CI = 0.07-0.87; p = 0.03). Conclusions and Public Health Implications: The integration of family planning and HIV/AIDS services could stress dual method use and encourage HIV status disclosure to partner.
- ItemAssessing the performance of the grain legume marketing system in northern Ghana(Academia, 2013) Aidoo R.; Mensah J.O; Opoku A; Abaidoo R. CThe main objective of this study was to examine costs, returns and efficiency levels associated with the activities of key players in the grain legume marketing chain in northern Ghana. A total of 140 market participants comprising 93 retailers, 39 wholesalers and eight (8) assemblers/aggregators were selected from major and satellite markets in the three Northern Regions of Ghana through a multi-stage sampling approach. Data for the study was obtained through personal interviews with the use of structured questionnaire. In addition to descriptive statistics, gross marketing margin, net margin and marketing efficiency analyses were performed using field data. The study identified a long chain of greater than four different channels/pathways through which grain legumes moved from farm gate to final consumers. Marketing of grain legumes in the study Districts was found to be profitable, as only 18% of gross marketing margin was spent as marketing costs, with the remaining amount retained as net marketing margin. The study further showed that net marketing margins were not equitably distributed among different trading partners along the marketing chain. Generally, net marketing margin for assemblers/aggregators was far higher than that received by wholesalers and retailers. Marketing activities by all traders in the grain legume value chain were performed efficiently, with efficiency ratios far in excess of 100%. Trading in groundnut was far more profitable than trading in cowpea and soyabean. The main constraints identified by grain legume traders were limited access to credit, high cost of transportation, poor road network and inadequate storage facilities
- ItemPhase behaviour of oat b-glucan/sodium caseinate mixtures varying in molecular weight(Food Chemistry, 2013) Agbenorhevi, Jacob K.; Kontogiorgos,, Vassilis; Kasapis, Stefan; 0000-0002-8516-7656The isothermal phase behaviour at 5 C of mixtures of sodium caseinate and oat b-glucan isolates varying in molecular weight (MW) was investigated by means of phase diagram construction, rheometry, fluorescence microscopy and electrophoresis. Phase diagrams indicated that the compatibility of the b-glucan/ sodium caseinate system increases as b-glucan MW decreases. Images of mixtures taken at various biopolymer concentrations revealed phase separated domains. Results also revealed that at the state of thermodynamic equilibrium, lower MW samples yielded considerable viscosity in the mixture. At equivalent hydrodynamic volume of b-glucan in the mixtures, samples varying in molecular weight exhibited similar flow behaviour. A deviation dependent on the protein concentration was observed for the high MW sample in the concentrated regime due to the size of b-glucan aggregates formed. Results demonstrate that by controlling the structural features of b-glucan in mixtures with sodium caseinate, informed manipulation of rheological properties in these systems can be achieved.
- ItemA density functional theory study of the mechanisms of oxidation of ethylene by rhenium oxide complexes†(Elsevier, 2013-04-01) Aniagyei, Albert; Tia, Richard; Adei, EvansThe oxo complexes of group VII B are of great interest for their potential toward epoxidation and dihy-droxylation. In this work, the mechanisms of oxidation of ethylene by rhenium-oxo complexes of thetype LReO3(L = O−, Cl, CH3, OCH3, Cp, NPH3) have been explored at the B3LYP/LACVP* level of theory.The activation barriers and reaction energies for the stepwise and concerted addition pathways involvingmultiple spin states have been computed. In the reaction of LReO3(L = O−, Cl, CH3, OCH3, Cp, NPH3) withethylene, it was found that the concerted [3 + 2] addition pathway on the singlet potential energy sur-faces leading to the formation of a dioxylate intermediate is favored over the [2 + 2] addition pathwayleading to the formation of a metallaoxetane intermediate and its re-arrangement to form the dioxylate.The activation barrier for the formation of the dioxylate on the singlet PES for the ligands studied isfound to follow the order O−>CH3> NPH3>CH3O−>Cl−> Cp and the reaction energies follow theorder CH3>O−> NPH3>CH3O−>Cl−> Cp. On the doublet PES, the [2 + 2] addition leading to the for-mation the metallaoxetane intermediate is favored over dioxylate formation for the ligands L = CH3,CH3O−,Cl−. The activation barriers for the formation of the metallaoxetane intermediate are found toincrease for the ligands in the order CH3
- ItemPrevalence and Risk Factors for Hypertension in Adansi South, Ghana: A Case for Health Promotion(SAGE Open, 2013-10) Duah, Amos F.; Werts, Niya; Hutton-Rogers, Laurencia; Amankwa, David; Otupiri, Easmon; 0000-0001-8986-1648Hypertension continues to emerge globally as one of the most dangerous cardiovascular disease risk factors. The toll of hypertension as a chronic disease on population health and the resultant impact on the often already stressed medical systems of developing nations is a serious concern. Shifting existing paradigm and resources from communicable to chronic disease prevention continues to be a formidable task. This article presents the results of a cross-section analysis of Adansi South, Ghana, residents (N = 539) 5 years and older to investigate the blood pressure status and select hypertension risk factors across all age groups. Approximately a third of Adansi South respondents (27.1%) were identified as hypertensive. While the largest percent of the hypertensive subset was in the 40 to 59 age group, of concern was the emerging pattern among young and adolescent respondents who were either identified as hypertensive and/or having modifiable risk factors for hypertension like elevated body mass index (BMI). A rationale for expanding adolescent health education and health promotion is offered, and alternative methods for deploying health promotion activities in resource-limited areas are proposed and discussed.
- ItemConcentrations and Health Risk Assessments of Heavy Metals in Fish from the Fosu Lagoon(Int. J. Environ. Res., 2014) Akoto,O; Eshun, Bismark F.; Darko, Godfred; Adei, E.; 0000-0001-7157-646XConcentrations of Cu, Pb, Cr, Cd, Mn, Ni, Fe and Zn were determined in the muscle samples of Sarotherodon melanotheron from the Fosu Lagoon in Cape Coast using atomic absorption spectrophotometer. The results showed that, metal concentration in the fish muscle was in the order Mn > Zn > Fe > Pb > Ni > Cd > Cu > Cr. Mean concentrations of Pb and Cd in the fish exceeded the maximum tolerable limit set by the European Union. Although the mean concentrations of some metals exceeded this limit, their estimated daily intakes were below their oral reference dose recommended by the international regulatory bodies. Health risk assessment of consumers from the intake of metal contaminated in the muscle of S. melanotheron from the lagoon was evaluated by using Health Risk Index (HRI) calculations. In this study, the total HRI through consumption of fish calculated by adding the individual HRIs was less than 1, indicating that there is no significant potential health risk associated with the consumption of fish from the Fosu Lagoon.