Assessment of radiological hazard indices from surface soil to individuals from major markets at Sagamu Ogun State, Nigeria

Assessment of radioactivity concentrations of 40K, 238U and 232Th insurface soil samples of major markets at Sagamu, Ogun State in Nigeriahad been determined by gamma spectrometry using Sodium IodideThallium doped NaI (TI) detector coupled with a pre-amplifier base to amultiple channel analyzer (MCA). 10 samples each were collected fromthree major markets: Falawo, Awolowo and Sabo. Highest radioactivityconcentrations of 40K, and 238U were obtained from Falawo market soilsamples with values 1274.26 ± 4.26 Bq/kg and 40.72 ± 3.12 Bq/kgrespectively while that of 232Th was obtained from Sabo soil sample withvalue 115.62 ± 16.39 Bq/kg. The mean external hazard index (Hex) andmean internal hazard index (Hin) for all the soil samples from Falawomarket were calculated to be 0.616 Bq/kg and 0.691Bq/kg respectively,and that of Awolowo market were 0.566 Bq/kg and 0.634 Bq/kg respectively. Also for Sabo market the mean values were calculated to be0.594 Bq/kg and 0.658 Bq/kg respectively. All the values obtained wereless than 1.0 Bq/kg as recommended for safety and therefore have nonegative radiological health implication to the people within the marketsand their environs.Keywords: Radioactivity concentration, radionuclide, hazard index,surface soil

Determination of Radiological Hazard Associated with the use of Imayan River Sediment as Building Material

The radioactivity concentrations of 40K, 238U and 232Th in sediment samples of Imayan river at Odogbolu local government area, Ogun State in Nigeria were determined by gamma spectrometry using NaI (TI) detector coupled with a pre-amplifier base to a multiple channel analyzer (MCA), these were then used to determine the radiological indicators; radium equivalent activity, internal and external hazard indices, and absorbed dose rate which translated to the annual effective dose rate. 10 sediment samples were collected from the river. The highest radioactivity concentrations of 40K, 238U and 232Th obtained from the sediment samples were 110.34 ± 10.68Bqkg-1, 9.02 ± 3.16Bqkg-1 and 11.56 ± 4.23Bqkg-1 respectively. The mean external hazard index (Hex) and mean internal hazard index (Hin) for all the sediment samples were calculated to be 0.066 Bqkg- 1 and 0.081Bqkg-1 respectively, while the mean radium equivalent activity was obtained to be 24.62Bqkg-1. Absorbed dose rate mean value was calculated to be 17.41nGyhr-1 with mean annual effective dose rate of 0.022mSvyr-1The values of the radiological indicators were found to be within the limits recommended for safety, indicating that the use of the sediment of the river as building material does not have radiological health hazards to the occupants of the buildings. ©JASEM KEYWORDS: Concentration, radionuclide, radiological indicators, absorbed dose rat

Hydrogen Exchange Mass Spectrometry for Studying Protein-Ligand Interactions

Hydrogen deuterium exchange (HDX) coupled with mass spectrometry is widely used for probing protein structure and dynamics. Protein-ligand interactions usually induce a reduction in the measured HDX rates an effect that may be ascribed to stabilization of the protein structure. This work aims to improve the general understanding of the changes in HDX patterns associated with ligand binding. We initially applied HDX for studying differences between oxy-hemoglobin (Oxy-Hb) and aquomet-hemoglobin (Chapter 2). The results show that the α and β subunits respond differently to the oxy to aquomet transition with the heme binding pocket being destabilized in both cases. The results suggest that enhanced structural dynamics in the heme binding pocket may have adverse effects on heme-protein interactions. Chapter 3 focuses on the different scenarios that can be encountered in an HDX experiment upon ligand binding. Myoglobin and hemoglobin were used as model systems, focusing on the oxy and deoxy states of both proteins. Our results demonstrate that ligand binding can be stabilizing or destabilizing, leading to decreased or increased HDX rates respectively. In Chapters 4 HDX was used to probe the changes in structural dynamics of caseinolytic protease P (ClpP), an antibiotic drug target, after binding ADEP antibiotics. The mechanism of ADEP binding and the N-terminal structure of ClpP is not well understood with conflicting x-ray structures reported in literature. Our findings demonstrate that the N-terminus of ClpP remains quite unstructured after ADEP binding, while belt region undergoes tightening. Pin 1, a peptidyl prolyl isomerase, binding to a cyclic peptide inhibitor was studied in Chapter 5. Characterization of Pin1-CRYPEVEIC interactions by other techniques has been iv difficult. This study demonstrates that binding of the inhibitor triggers an overall stabilization of Pin 1. We identify a loop that interacts with basic sites of the ligand and that becomes destabilized upon ligand binding. This destabilization is ascribed to steric clashes between the peptide inhibitor and the protei

THE DETECTION OF HEPATITIS C VIRAL NS3-4A PROTEASE AND PROSTATE SPECIFIC ANTIGEN USING ELECTROCHEMICAL TECHNIQUES

This work attempts to detect hepatitis C viral (Hep CV) NS3-4A protease and prostate specific antigen (PSA) proteins using electrochemical methods. The sensing probes used in detecting these biological markers are their inhibitory peptides. The inhibitory peptide for the hepatitis C viral NS3-4A protease is Asp-Glu-Ile-Val-Pro-Nva with an IC50of 7.5 pM and the inhibitory peptide for prostate specific antigen is the peptide Ser-Lys-Ser- Lys-Ser-Lys-Ser-Cys-Val-Phe-Ala-His-Asn-Tyr-Asp-Tyr-Leu-Val-Cys with a K, of 0.8 pM. The steps involved in the fabrication of the sensor surface include the formation of a self assembled monolayer (SAM) using a thioctic acid modified ferrocene compound. The use of a thioctic acid labelled compound facilitates the chemisorption of the ferrocene probe to the electrode surface. The SAM is then diluted using an ethanolic solution of hexanethiol. This will help backfill the films and remove physisorbed molecules from the electrode surface. The sensing probes are then covalently attached to the surface and are used for subsequent studies with either NS3-4A protease or PSA. Our studies show that the Hep CV NS3-4A protease can be detected using the biosensor approach at very low concentrations and this sensor approach is also very specific in the presence of high concentrations of human serum albumin (HSA). The changes in sensor surface can be directly correlated to the concentration o f the protease. Studies using this approach with PSA also show similar result

Assessment of radioactivity concentrations and effective of radionuclides in selected fruits from major markets at Ijebu – Ode in Ogun State, southwest of Nigeria

Natural Radionuclides are elements that are found in the air, water and soil. They find their ways in to the plants through the leaves and absorption of nutrients and water from the soil through the roots. Intake of fruits is very essential for human beings as part of balance diet. The concentrations of natural radionuclides in some fruits from three major markets at Ijebu- Ode town in Nigeria were determined and annual committed effective dose to the consumers was also determined. The gamma spectrometry method was used for the analysis. The highest concentrations of 40K, 238U and 232Th were from pineapple of value 102.36 ± 10.81Bqkg-1, orange of value 12.18 ± 4.36Bqkg-1 and mango of value 8.01 ± 3.25 Bqkg-1 respectively. The average annual committed effective dose of the natural radionuclides to the consumers was calculated to be 0.11mSvyr-1, which is below the limit of 0.3mSvyr-1 recommended globally. This indicates that the ingestion of these radionuclides through the consumption of these fruits has no radiological health hazard to the consumers.Keywords: Fruit, radionuclides, concentration, dose, gamma spectrometr

Breast feeding, bottle feeding and caries experience in children aged 6 months to 5 years in Lagos state, Nigeria

Objective: To determine the relationship between breast feeding, bottle feeding pattern and caries experience in young children. Methods: Children aged 6 months – 5 years from 3 randomly selected local governments in Lagos State were examined intraorally. Structured questionnaire were administered to the mothers to inquire about the feeding pattern of their children. Results: The prevalence of dental caries amongst the children was 10.5%. The group most affected with caries was among the predominantly exclusively breast fed (14.6%) compared to 9.4% of those who were exclusively breast fed. No cause and effect relationship was established between the duration of breast-feeding and dental caries, however the longer the duration of breast-feeding the higher the caries prevalence among them. The prevalence of caries also increased with the longer duration of bottle feeding till 18 months after which it declined. Mode of putting child to sleep rather than the bottle content was statistically associated with caries prevalence. (p < 0.05) Conclusion: The multifactorial nature involved in cariogenesis is further demonstrated. The mode of putting the child to sleep is a strong factor in the caries process in young children.Key words: Breast-feeding, bottle-feeding, carie

Annual Committed Effective Doses of Primordial Radionuclides and Excess Lifetime Cancer Risk to the Consumers of Some Foodstuffs in Lagos, Southwest of Nigeria

Food plays vital role in the survival of man as it provides necessary nutrients to the body in orderto carry out the daily activities and also to be in good health. Activity concentrations of 40K,238Uand 232Th in some foodstuffs from three highly rated markets in Lagos, Southwest of Nigeriahave been determined by gamma spectrometry method using NaI (TI) detector coupled with a preamplifierbase to a multiple channel analyzer (MCA). Fifteen (15) samples of maize flour, yamflour, beans, cassava flour and rice were randomly purchased from the markets: Ketu, Oyingboand Ikeja. The highest activity concentrations for 40K, 238U and 232Th were 153.47 ± 10.34 Bqkg−1, 9.26 ± 2.17 Bq kg−1 and 15.36 ± 4.05 Bq kg−1, respectively, all from yam flour. The meanconcentrations of 40K for all the samples were obtained to be 102.33 ± 7.04 Bq kg−1, 5.79 ± 1.35Bq kg˗1 for 238U and 9.15 ± 2.36 Bq kg−1 for 232Th. The average annual committed effective doseof all the natural radionuclides to the consumers of the foodstuffs was determined to be 0.144 mSvyr−1 and average excess lifetime cancer risk to the consumers was determined to be 0.503 x 104.The values obtained were below the worldwide limits of 1 mSv yr−1 and 0.29 x 10−3,respectively, which indicated that consumption of the foodstuffs had no significant negativeradiological health risks to the consumers. Keywords: Radionuclide; Activity concentration; Foodstuff; Dose; Gamma spectrometry

Radioactivity Assessment of 40K, 238U and 232Th in Surface Soil Samples of Igbokoda, Southwest of Nigeria

Natural radionuclides are found in soil and are capable of disintegrating leading to the release of ionizing radiations that can have harmful effects on individuals exposed to them most especially when exceeding the recommended global limits of radiological parameters. Assessment of activity  concentrations of 40K, 238U and 232Th in surface soil samples from different locations  at Igbokoda where crude oil exploration was taking place, at Ondo State in Nigeria, had been determined by gamma spectrometry using NaI (TI) detector coupled with a pre-amplifier base connected to a multiple channel analyzer (MCA) which was used to calculate the radiological indicators. 10 samples were collected from the study area putting into consideration the densely populated parts where crude oil exploration and drilling its wells were taking place. The mean activity  concentrations of 40K,  238U and 232Th obtained from the soil samples were 494.64 ± 10.46 , 19.76 ± 3.09 and 31.98 ± 5.10 Bq kg–1,respectively. The mean external hazard index (Hex) and mean internal hazard index (Hin) for all the soil samples were 0.2836 and 0.3370, respectively, while the mean radium equivalent activity was 104.92 Bq kg–1. The mean absorbed dose rate value was 49.68 nGy hr–1 with mean annual effective dose equivalent of 0.0610 mSv yr–1. The mean excess lifetime cancer risk for outdoor exposure was 0.2132 x 10–3. The values of the radiological parameters: mean external and internal hazard indices, mean radium equivalent activity, mean absorbed dose rate, mean annual effective dose equivalent and mean excess lifetime cancer risk were within the recommended limits of 1.0 Bq kg–1, 370 Bq kg–1, 55.00 nGy hr–1, 1.0 mSv yr–1 and 1.45 x 10–3, respectively.Keywords:  Activity concentration, Exposure, Health implication, surface soi

Evaluation of radiological hazard indices and excess lifetime cancer risk associated with the use of Ogun River sediment as building material

The radioactivity concentrations of 40K, 238U and 232Th in sediment samples of Ogun river at Abeokuta, Ogun State in Nigeria were evaluated by gamma spectrometry using NaI (TI) detector coupled with a pre-amplifier base to a multiple channel analyzer (MCA), these were then used to determine the radiological indicators; radium equivalent activity, internal and external hazard indices, and absorbed dose rate which translated to the annual effective dose rate. 10 sediment samples were collected from the river. The values of the radiological indicators and excess lifetime cancer risk were found to be within the limits recommended, indicating that the use of the sediment of the river as building material does not have radiological health hazards to the occupants of the buildings.Keywords: Concentration, Radionuclide, Radiological Indicators, Cancer Ris

Evaluation of Primordial Radionuclides in Ocimum gratissimum and health Risk to the Consumers at Ewekoro Southwest of Nigeria

Primordial radionuclides are transported in to the plants through the leaves and roots. Medicinal plants are widely used in Africa for prevention and treatment of diseases. Ocimum Gratissimum is medicinal plant that is so used in southwest of Nigeria due to its multifunctional traditional medicinal health uses and as spice in cooking. The research is to determine the radiological health risk of these primordial radionuclides to the&nbsp; consumers of Ocimum Gratissimum in the study area. Fresh leaves of the medicinal plant were plucked from ten (10) different locations at Ewekoro where mining of limestone had been taking place in Ogun State, southwest of Nigeria, been the part of the plant that was commonly used. The concentrations of 40K, 238U and 232Th in the fresh leaves were determined using gamma spectrometry method, and average annual committed effective dose to the adult consumers was determined. No artificial radionuclide was detected. The highest annual committed effective doses of 40K, 238U and 232Th to the consumers of Ocimum Gratissimum were obtained to be 0.00133mSvy-1, 0.00147mSvy-1 and 0.00336mSvy-1 respectively. The highest excess lifetime cancer risk of 40K, 238U and 232Th to the consumers were calculated to be 0.0211 x 10-3, 0.0136 x 10-3 and 0.1434 x 10-3 respectively. The average annual committed effective dose and average excess lifetime cancer risk of the radionuclides to the consumers were calculated to be 0.0109mSvy-1 and 0.0379 x 10-3 respectively. The values were below the limits of 0.3mSvy-1 and 0.29 x 10-3 respectively,&nbsp; recommended globally. The consumers of the medicinal plant do not have significant radiological health risk. Furthermore, the results obtained can serve as reference data for future studies in the study area and its environs. Keywords: Primordial Radionuclide, Medicinal plant, Dose, Cance