62 research outputs found

    Accelerating Rural Growth Through Collective Action: Groups\u27 Activities and Determinants of Participation in Southwestern Nigeria

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    This study was conducted to investigate the types of activities promoted by cooperative groups and the determinants of participation intensity of members in cooperative activities in southwestern Nigeria. A multistage sampling approach was used to select 326 cooperators (45 groups). Data collected were analyzed using descriptive statistics, difference of means test, and Tobit regression.Cooperative groups engaged in farm and off-farm activities such as arable crop production, fish farming, agricultural products processing, and produce marketing, among others. Farm input procurements and access to market information (74 percent), cooperative credits and thrift (53 percent), social networking (37 percent), multipurpose commercial activities (21.6 percent), and political influence (17 percent) were given as reasons for interest and participation in groups\u27 activities. Income realized by cooperators was significantly and consistently higher than income of non-cooperators who engaged in the same economic activity. Participation intensity was influenced by gender, farm size cultivated, and the social status of members

    Visual Acuity Improvement When Switching From Ranibizumab To Aflibercept Is Not Sustained

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    PURPOSE: To assess whether visual benefits exist in switching to aflibercept in patients who have been chronically treated with ranibizumab for neovascular age-related macular degeneration. METHODS: A multicenter, national, electronic medical record database study was performed. Patients undergoing six continuous monthly ranibizumab injections and then switched to continuous aflibercept were matched to those on continuous ranibizumab therapy. Matching was performed in a 2:1 ratio and based on visual acuity 6 months before and at the time of the switch, and the number of previous ranibizumab injections. RESULTS: Patients who were switched to aflibercept demonstrated transiently significant improvement in visual acuity that peaked at an increase of 0.9 Early Treatment Diabetic Retinopathy Study letters 3 months after the switch, whereas control patients continued on ranibizumab treatment showed a steady decline in visual acuity. Visual acuity differences between the groups were significant (P < 0.05) at 2, 3, and 5 months after the switch. Beginning at 4 months after the switch, the switch group showed a visual acuity decline similar to the control group. CONCLUSION: Transient, nonsustained improvement in visual acuity occurs when switching between anti-vascular endothelial growth factor agents, which may have implications in treating patients on chronic maintenance therapy on one anti-vascular endothelial growth factor medication

    Assessment of different quantification metrics of [Âč⁞F]-NaF PET/CT images of patients with abdominal aortic aneurysm

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    Background: We aim to assess the spill-in effect and the benefit in quantitative accuracy for [18F]-NaF PET/CT imaging of abdominal aortic aneurysms (AAA) using the background correction (BC) technique. Methods: Seventy-two datasets of patients diagnosed with AAA were reconstructed with ordered subset expectation maximization algorithm incorporating point spread function (PSF). Spill-in effect was investigated for the entire aneurysm (AAA), and part of the aneurysm excluding the region close to the bone (AAAexc). Quantifications of PSF and PSF+BC images using different thresholds (% of max. SUV in target regions-of-interest) to derive target-to-background (TBR) values (TBRmax, TBR90, TBR70 and TBR50) were compared at 3 and 10 iterations. Results: TBR differences were observed between AAA and AAAexc due to spill-in effect from the bone into the aneurysm. TBRmax showed the highest sensitivity to the spill-in effect while TBR50 showed the least. The spill-in effect was reduced at 10 iterations compared to 3 iterations, but at the expense of reduced contrast-to-noise ratio (CNR). TBR50 yielded the best trade-off between increased CNR and reduced spill-in effect. PSF+BC method reduced TBR sensitivity to spill-in effect, especially at 3 iterations, compared to PSF (P-value ≀ 0.05). Conclusion: TBR50 is robust metric for reduced spill-in and increased CNR

    Iterative reconstruction incorporating background correction improves quantification of [18F]-NaF PET/CT images of patients with abdominal aortic aneurysm

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    Background A confounding issue in [18F]-NaF PET/CT imaging of abdominal aortic aneurysms (AAA) is the spill in contamination from the bone into the aneurysm. This study investigates and corrects for this spill in contamination using the background correction (BC) technique without the need to manually exclude the part of the AAA region close to the bone. Methods Seventy-two (72) datasets of patients with AAA were reconstructed with the standard ordered subset expectation maximization (OSEM) algorithm incorporating point spread function (PSF) modelling. The spill in effect in the aneurysm was investigated using two target regions of interest (ROIs): one covering the entire aneurysm (AAA), and the other covering the aneurysm but excluding the part close to the bone (AAAexc). ROI analysis was performed by comparing the maximum SUV in the target ROI (SUVmax(T)), the corrected cSUVmax (SUVmax(T) − SUVmean(B)) and the target-to-blood ratio (TBR = SUVmax(T)/SUVmean(B)) with respect to the mean SUV in the right atrium region. Results There is a statistically significant higher [18F]-NaF uptake in the aneurysm than normal aorta and this is not correlated with the aneurysm size. There is also a significant difference in aneurysm uptake for OSEM and OSEM + PSF (but not OSEM + PSF + BC) when quantifying with AAA and AAAexc due to the spill in from the bone. This spill in effect depends on proximity of the aneurysms to the bone as close aneurysms suffer more from spill in than farther ones. Conclusion The background correction (OSEM + PSF + BC) technique provided more robust AAA quantitative assessments regardless of the AAA ROI delineation method, and thus it can be considered as an effective spill in correction method for [18F]-NaF AAA studies
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