114 research outputs found

    A Low Cost Synthesis and Characterization of CuO Nanoparticles for Photovoltaic Applications

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    A simple low cost chemical route has been used to synthesize cupric oxide nanoparticles. The synthesized CuO nanoparticles were characterized using XRD, TEM and UV-absorption. X-ray diffraction analysis showed the synthesized nanoparticles to be a pure cupric oxide. EDAX analysis showed the presence of copper and Oxygen in the as prepared CuO nano particles, with the AAS indicating that Cu2+ represented 53.5% of the sample. The particle size and particle size distribution of the cupric oxide nanoparticles were obtained by transmission electron microscopy (TEM) whereas the crystallite size and crystallite size distribution were obtained by X-ray diffraction. The particle size was found to be between 20 nm and 60 nm. The particle size distribution obtained from cumulative percentage frequency plots features a log-normal function. Absorbance measurements and analysis showed that the material has an absorbance peak at 314 nm and energy bandgap of 1.48 eV, making it a good candidate for photovoltaic applications

    Integration of genetics into a systems model of electrocardiographic traits using humanCVD BeadChip

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    <p>Background—Electrocardiographic traits are important, substantially heritable determinants of risk of arrhythmias and sudden cardiac death.</p> <p>Methods and Results—In this study, 3 population-based cohorts (n=10 526) genotyped with the Illumina HumanCVD Beadchip and 4 quantitative electrocardiographic traits (PR interval, QRS axis, QRS duration, and QTc interval) were evaluated for single-nucleotide polymorphism associations. Six gene regions contained single nucleotide polymorphisms associated with these traits at P<10−6, including SCN5A (PR interval and QRS duration), CAV1-CAV2 locus (PR interval), CDKN1A (QRS duration), NOS1AP, KCNH2, and KCNQ1 (QTc interval). Expression quantitative trait loci analyses of top associated single-nucleotide polymorphisms were undertaken in human heart and aortic tissues. NOS1AP, SCN5A, IGFBP3, CYP2C9, and CAV1 showed evidence of differential allelic expression. We modeled the effects of ion channel activity on electrocardiographic parameters, estimating the change in gene expression that would account for our observed associations, thus relating epidemiological observations and expression quantitative trait loci data to a systems model of the ECG.</p> <p>Conclusions—These association results replicate and refine the mapping of previous genome-wide association study findings for electrocardiographic traits, while the expression analysis and modeling approaches offer supporting evidence for a functional role of some of these loci in cardiac excitation/conduction.</p&gt

    Investigating associations between the built environment and physical activity among older people in 20 UK towns.

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    BACKGROUND: Policy initiatives such as WHO Age Friendly Cities recognise the importance of the urban environment for improving health of older people, who have both low physical activity (PA) levels and greater dependence on local neighbourhoods. Previous research in this age group is limited and rarely uses objective measures of either PA or the environment. METHODS: We investigated the association between objectively measured PA (Actigraph GT3x accelerometers) and multiple dimensions of the built environment, using a cross-sectional multilevel linear regression analysis. Exposures were captured by a novel foot-based audit tool that recorded fine-detail neighbourhood features relevant to PA in older adults, and routine data. RESULTS: 795 men and 638 women aged 69-92 years from two national cohorts, covering 20 British towns, were included in the analysis. Median time in moderate to vigorous PA (MVPA) was 27.9 (lower quartile: 13.8, upper quartile: 50.4) minutes per day. There was little evidence of associations between any of the physical environmental domains (eg, road and path quality defined by latent class analysis; number of bus stops; area aesthetics; density of shops and services; amount of green space) and MVPA. However, analysis of area-level income deprivation suggests that the social environment may be associated with PA in this age group. CONCLUSIONS: Although small effect sizes cannot be discounted, this study suggests that older individuals are less affected by their local physical environment and more by social environmental factors, reflecting both the functional heterogeneity of this age group and the varying nature of their activity spaces

    Genotypic and phenotypic characterisation of three local chicken ecotypes of Ghana based on principal component analysis and body measurements

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    This study was to characterise three Ghanaian local chicken ecotypes, namely, Interior Savannah, Forest and Coastal Savannah ecotypes, based on morphological data and single nucleotide polymorphism (SNP) genotypes. Morphological data including shank length, body girth, back length, thigh length, beak length, comb length and wattle length were collected. Blood samples were also obtained for SNP genotyping with Affymetrix chicken 600k SNP chip. Principal component analysis showed that Forest and Coastal Savannah birds were closely related. Generally, all three ecotypes seemed very diverse especially birds from the Interior Savannah zone. Morphological characterisation showed ecotype, sex and pen had significant effect on body weights (p0.05). Very few of the phenotypes reported to be associated with heat resistance – frizzle (2%) and naked neck (1.6%) – were found in the current study. It is concluded that the three local ecotypes are genetically diverse but with similar morphological features

    Performance of three local chicken ecotypes of Ghana naturally exposed to velogenic Newcastle disease virus

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    This study was to evaluate the performance of three Ghanaian local ecotypes that were exposed to a natural velogenic Newcastle Disease Virus (NDV) challenge. The birds at four weeks of age had been challenged with a lentogenic (vaccine) form of the virus and later exposed to velogenic NDV when their anti-NDV antibody titres had fallen below 1000. All the birds lost weight over the 21 days of exposure to the virus, with the Coastal Savannah ecotype showing the fastest weight loss albeit not significant (p\u3e0.05). Lesion scores for all ecotypes were low and similar across ecotypes suggesting that the challenge was not severe. Heritability was zero for the lesion scores and low (0.01) for post-challenge growth rate across ecotypes. Hence, not much progress can be made in selection to improve post infection growth rate

    Investigation of Genetic Resistance to Newcastle Disease in Local Chickens in Tanzania using Natural Challenge by Field Velogenic NDV Strains

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    Genetic resistance to Newcastle disease among three ecotypes of Tanzanian local chickens, Ching’wekwe, Kuchi and Morogoro MEDIUM was investigated by natural challenge with endemic velogenic strains of Newcastle disease virus (vNDV). The study was designed to determine variations in susceptibility and response to NDV among the three ecotypes. Naturally NDV-infected seeders were introduced into flocks of susceptible chickens under a controlled environment. For each bird, body weights were measured at 0, 7, 9, 11, 13, 15, 17, and 25 days post-exposure. Flock mortality was assessed every 8 hours for the first three days and then every 12 hours thereafter until 29 days post-exposure. Date and time of death was recorded, and post-mortem examinations performed for each dead chicken. Lesions on the trachea, proventriculus, intestines, and caecal tonsils were scored for severity ranging from 0 to 3. Linear models were used for survival days, post-exposure growth rate and average lesion score. Preliminary results indicate that post-exposure weight reduction in Ching’wekwe was significantly less than in Morogoro Medium and Kuchi. No significant differences were observed in the lesion scores and survival times among the three ecotypes after exposure. More data is being collected for more comprehensive analysis

    Phenotypic and genotypic diversity of selected Free Range Local Chickens in Tanzania

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    Free range local chickens are an important source of protein as meat and eggs in Tanzania. Few studies have been done to improve their productivity. To this end, this paper focuses on characterizing three common Tanzanian local chicken ecotypes. Morphologic and genetic diversity studies show that the Kuchi have relatively higher body dimension measures than Ching’wekwe and Morogoro medium and that the Ching’wekwe ecotype is genetically more related to Morogoro medium than to the Kuchi ecotype. These differences indicate variation in traits that call for further research and opportunities to improve productivity of free range local chickens

    Genetic parameters and genomic regions associated with growth rate and response to Newcastle disease in local chicken ecotypes in Ghana and Tanzania

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    Local chicken breeds play an important role in the livelihoods of people in both rural and urban areas of Africa. One of the main constraints to the poultry sector in many sub-Saharan countries is disease, with Newcastle disease (ND) being the most important. Because vaccination does not adequately control ND, selective breeding offers an effective complement, provided there is genetic variation in resistance, tolerance and/or response to ND. We investigated this topic by challenging 6 local ecotypes from Ghana and Tanzania with a lentogenic (vaccine) strain of Newcastle disease virus (NDV), then measuring growth, anti-NDV antibody levels, and viral load from hatch to 38 days of age. We estimated variance components and performed a genome-wide association study using 2800 birds genotyped with the 600K Affymetrix chicken genotyping array. Heritabilities were moderate to high (0.14 – 0.55) for all the traits studied, which indicates that selection to improve these breeds for resistance to ND can be feasible. GWAS also revealed several genomic regions that explained ≥0.5% of the genetic variance, including a candidate gene region for antibody response on GGA1. We conclude that all traits investigated in this study appear to be highly polygenic in nature. Future studies will characterize differences between the breeds/ecotypes, determine if large breed-specific quantitative trait loci can be identified, and evaluate the response of the same birds to endemic, velogenic NDV strains

    Discovery and replication of SNP-SNP interactions for quantitative lipid traits in over 60,000 individuals

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    Background The genetic etiology of human lipid quantitative traits is not fully elucidated, and interactions between variants may play a role. We performed a gene-centric interaction study for four different lipid traits: low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), total cholesterol (TC), and triglycerides (TG). Results Our analysis consisted of a discovery phase using a merged dataset of five different cohorts (n = 12,853 to n = 16,849 depending on lipid phenotype) and a replication phase with ten independent cohorts totaling up to 36,938 additional samples. Filters are often applied before interaction testing to correct for the burden of testing all pairwise interactions. We used two different filters: 1. A filter that tested only single nucleotide polymorphisms (SNPs) with a main effect of p < 0.001 in a previous association study. 2. A filter that only tested interactions identified by Biofilter 2.0. Pairwise models that reached an interaction significance level of p < 0.001 in the discovery dataset were tested for replication. We identified thirteen SNP-SNP models that were significant in more than one replication cohort after accounting for multiple testing. Conclusions These results may reveal novel insights into the genetic etiology of lipid levels. Furthermore, we developed a pipeline to perform a computationally efficient interaction analysis with multi-cohort replication
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