Democracy Takes Another Step Forward in #GhanaDecides 2016

Kafui Tsekpo and Alexander Afram analyse the implications behind the 2016 general elections in Ghana

How poor public transit makes idiots of us all

America's mass transit systems are in a sorry state, and only a tiny minority of Americans makes use of them. For Kafui Attoh America's transit is "idiotic" in two ways: in the sense that it is stupid to have not invested more in it, and in the way it isolates those unable to use cars, excluding them from urban public ..

Mechanistic analysis and computer simulation of impact breakage of agglomerates: Effect of surface energy

Agglomerates are ubiquitous as intermediate or manufactured products in chemical, pharmaceutical and food industries. During handling and processing they may suffer breakage if they are weak. On the other hand, if they are too strong, their dispersion and disintegration could be difficult. The control of their mechanical strength is therefore highly desirable. However, the analysis of agglomerate strength is complex due to the large number of parameters that influence agglomerate behaviour, such as the primary particle size, density and elastic modulus, and the interparticle bond strength. A simple mechanistic model is presented here which relates the number of broken contacts in agglomerate due to impact velocity, interparticle adhesion energy and the particle properties of the particles forming the agglomerate. The model is based on the hypothesis that the energy used to break contacts during impact is proportional to the incident kinetic energy of the agglomerate. The damage ratio defined as the ratio of broken contacts to the initial number of bonds is shown to depend on the dimensionless group, Δ, in the form (ρV2D5/3E2/3)/ Γ5/3, where V is the impact velocity, E the elastic modulus, D the particle diameter, ρ the particle density and Γ the interface energy. This dimensionless group, Δ, incorporates the Weber number, (ρDV2/Γ), which was previously shown to be influential in agglomerate breakage, and may be presented in the form, Δ=WeIe2/3 , where Ie = ED/ Γ. The predicted dependency of the damage ratio on the surface energy has been tested using Distinct Element Method (DEM). Four different agglomerates have been formed and impacted against a target for three different values of the surface energy of the primary particles. The simulation results show that the effect of surface energy is better described by the above mechanistic model than by the Weber number alone, as previously used to characterise the impact strength of agglomerates

Options in human papillomavirus (HPV) detection for cervical cancer screening: comparison between full genotyping and a rapid qualitative HPV-DNA assay in Ghana.

BACKGROUND: Modern cervical cancer screening increasingly relies on the use of molecular techniques detecting high-risk oncogenic human papillomavirus (hr-HPV). A major challenge for developing countries like Ghana has been the unavailability and costs of HPV DNA-based testing. This study compares the performance of careHPV, a semi-rapid and affordable qualitative detection assay for 14 hr-HPV genotypes, with HPV genotyping, for the detection of cytological cervical squamous intraepithelial lesions (SIL). METHODS: A study comparing between frequency matched HIV-1 seropositive and HIV-seronegative women was conducted in the Cape Coast Teaching Hospital, Ghana. A systematic sampling method was used to select women attending clinics in the hospital. Cervical samples were tested for HPV by careHPV and Anyplex-II HPV28 genotyping assay, and by conventional cytology. RESULTS: A total of 175 paired results (94 from HIV-1 seropositive and 81 from HIV-seronegative women) were analyzed based on the ability of both tests to detect the 14 hr-HPV types included in the careHPV assay. The inter-assay concordance was 94.3% (95%CI: 89.7-97.2%, kappa = 0.88), similar by HIV serostatus. The careHPV assay was equally sensitive among HIV-1 seropositive and seronegative women (97.3% vs. 95.7%, p = 0.50) and slightly more specific among HIV-seronegative women (85.0% vs. 93.1%, p = 0.10). careHPV had good sensitivity (87.5%) but low specificity (52.1%) for the detection of low SIL or greater lesions, but its performance was superior to genotyping (87.5 and 38.8%, respectively). Reproducibility of careHPV, tested on 97 samples by the same individual was 82.5% (95%CI: 73.4-89.4%). CONCLUSIONS: The performance characteristics of careHPV compared to genotyping suggest that this simpler and cheaper HPV detection assay could offer a suitable alternative for HPV screening in Ghana

Pore-scale Modeling of Viscous Flow and Induced Forces in Dense Sphere Packings

We propose a method for effectively upscaling incompressible viscous flow in large random polydispersed sphere packings: the emphasis of this method is on the determination of the forces applied on the solid particles by the fluid. Pore bodies and their connections are defined locally through a regular Delaunay triangulation of the packings. Viscous flow equations are upscaled at the pore level, and approximated with a finite volume numerical scheme. We compare numerical simulations of the proposed method to detailed finite element (FEM) simulations of the Stokes equations for assemblies of 8 to 200 spheres. A good agreement is found both in terms of forces exerted on the solid particles and effective permeability coefficients

Chemical composition and antioxidant activities of different parts of Ficus sur

Introduction: Ficus sur is a plant widely used in traditional pharmacopoeia in Togo. So, this study aimed the assessment of antioxidant properties and identification of some compounds from the ethanolic extracts of different parts of the plant (leaves, fruits, roots, and barks). Methods: The phenolic and flavonoid contents of the ethanolic extracts of different organs of Ficus sur were assessed using conventional known methods. The DPPH radical scavenging and the ferric-reducing antioxidant power (FRAP) assays were used to highlight the antioxidant activities. The different extract samples were also analysed by liquid chromatography coupled to a quadrupole-time of flight mass detector (ESI-QTOF). Results: Total phenolic contents (TPCs) for 1 mg of dry extract ranged from 489.40 ± 7.48 μg GAE (gallic acid equivalents) for the bark to 62.34 ± 2.66 μg GAE for unripe fruits. The bark exhibited the highest flavonoid content, which was closed to 90.20 ± 3.72 μg QE (quercetin equivalents)/mg of dry extract. The radical scavenging activities of the bark and unripe fruits were 56.50 ± 0.29 and 7.3 ± 0.30 μg QE/mg of dry extract, respectively. In the same order, the FRAP values of the two organs were 104.57 ± 4.75 and 19.61 ± 0.22 μmol FeSO4 Eq/mg of dry extract. Many compounds including notoginsenoside R10; 4’,5,7-trihydroxyflavan-3-ol; catechin; and boviquinone 4 were identified. Conclusion: The various organs of Ficus sur are a source of bioactive compounds especially phenolic compounds and flavonoids with antioxidant activit