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Page will reload when a filter is selected or excluded.- Nigeria 13 results 13
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- Hypertension is a public health challenge due to its high prevalence, and is a major risk factor for cardiovascular diseases. Hypertension is a complex disease resulting from an interaction of genes and environmental factors. Inconsistent association between polymorphisms of the renin angiotensin aldosterone, the atrial natriuretic peptide systems and hypertension has been reported among various ethnic groups, but not for the Efiks and Ibibios in south-south Nigeria. This study was designed to determine the frequency of gene polymorphisms of these two systems and their association with hypertension in Calabar and Uyo, Nigeria. A population-based case control design was used. A total of 1224 participants, 612 each of patients and controls were randomly recruited from hypertension clinics and the general population. Genotyping of the M235T allele of the angiotensinogen, Insertion/Deletion allele (I/D) of the angiotensinogen converting enzyme, A1166C allele of the angiotensin II type I receptor and C664G allele of the atrial natriuretic peptide genes to identify variants was performed using polymerase chain reaction and restriction enzyme digestion. The Hardy-Weinberg equation was used to calculate the allele and genotype frequencies. Plasma angiotensinogen levels were measured by Enzyme Linked Immunosorbent Assay. Hypertensinogenic factors such as age, familial history, physical exercise and drinking were assessed using questionnaires. Descriptive statistics, chi-square, multiple regression analysis and odds ratio were used to analyze the data. The frequency of the genotypes M235M, M235T, T235T of the M235T allele for the Efiks were 0.4, 7.7, 92 % in patients and 0, 6, 94 % in controls; for the Ibibios were 0.5, 1.2, 87 % in patients and 0, 7, 93 % in controls. The I/D genotypes II, ID, DD frequencies for the Efiks were 11, 44, 46 % in patients and 16, 45, 39 % in controls; for the Ibibios were 11, 40, 49 % in patients and 13, 49, 38 % in controls. The frequency of the A1166C carriers was 1 % while 99 % of the study population had the wild type A1166A genotype for the A1166C allele. Only the CC genotype was observed for the C664G allele. These frequencies did not conform to the Hardy-Weinberg assumptions. There were no significant differences between the genotype frequencies of patients and controls. Plasma angiotensinogen values were significantly higher in the patients with M235T allele than in the controls. Age was a positive predictor for systolic blood pressure (SBP, r = 0.60) in patients and diastolic blood pressure (DBP, r = 0.56) in controls. Other hypertensinogenic variables were not predictors for SBP and DBP in the population (p < 0.05). The Insertion/Deletion allele was a risk factor for hypertension, (O.R = 1.15). A high frequency was observed for the M235T allele and the Insertion/Deletion allele, which was associated with an increased risk for hypertension. The lack of association between the alleles of the M235T, A1166C and the C664G and hypertension suggests that other loci or environmental factors are involved in the disease outcome. 2 results 2
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- One of the major problems facing drilling operations is the performance of the drilling Bits. The ability of the Bit to crush the rock and the removal of the crushed rock from the wellbore effectively. It is necessary to understand the fundamental difference in Bit design for different rock textures because many variables tend to affect Bit optimization, particularly the type of formations, economics and Bit selection. However, the cost of drilling a well has a considerable effect on the selection and the design of a particular Bit, therefore this paper focuses on the development of a model that will predict future Bit performance and optimization for actual well design and construction. The variables to optimize Bit performance provide means of handling cost estimation hence the model becomes more realistic and dynamic in its application. The input variables and control factors for this model are stretched to minimize cost and maximize performance. The cost per foot and the break even calculations were done using data from the reference well X14 and also the evaluation well X35 from a field-X in the Niger Delta region. A Visual Basic dot Net program model was developed, tested and validated with the real field data to know its accuracy. The model interface shows the detailed application of the Bits in validating the data to provide the equivalent results for the five different Bits. Each set of the Bit record was ran separately on the software and the results for each application developed for comparison. In the software, data application were grouped into two distinct methods namely; rentals method and historical method. Under the rentals method, data were uploaded into the software and ran to generate results while the historical method was basically used for model prediction. The breakeven analysis provided a technique for calculating the performance required for an alternative Bit type to match the cost per foot of the current Bit. Based on the model results, Hughes Tungsten Carbide (HTC) Bit and Security Bit (SEC) used to drill well X14 and X35 were well optimized and should be encouraged in drilling wells within the area. 2 results 2
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