Diabetes in Sub Saharan Africa 1999-2011: Epidemiology and Public Health Implications. A Systematic Review.

Diabetes prevalence is increasing globally, and Sub-Saharan Africa is no exception. With diverse health challenges, health authorities in Sub-Saharan Africa and international donors need robust data on the epidemiology and impact of diabetes in order to plan and prioritise their health programmes. This paper aims to provide a comprehensive and up-to-date review of the epidemiological trends and public health implications of diabetes in Sub-Saharan Africa. We conducted a systematic literature review of papers published on diabetes in Sub-Saharan Africa 1999-March 2011, providing data on diabetes prevalence, outcomes (chronic complications, infections, and mortality), access to diagnosis and care and economic impact. Type 2 diabetes accounts for well over 90% of diabetes in Sub-Saharan Africa, and population prevalence proportions ranged from 1% in rural Uganda to 12% in urban Kenya. Reported type 1 diabetes prevalence was low and ranged from 4 per 100,000 in Mozambique to 12 per 100,000 in Zambia. Gestational diabetes prevalence varied from 0% in Tanzania to 9% in Ethiopia. Proportions of patients with diabetic complications ranged from 7-63% for retinopathy, 27-66% for neuropathy, and 10-83% for microalbuminuria. Diabetes is likely to increase the risk of several important infections in the region, including tuberculosis, pneumonia and sepsis. Meanwhile, antiviral treatment for HIV increases the risk of obesity and insulin resistance. Five-year mortality proportions of patients with diabetes varied from 4-57%. Screening studies identified high proportions (> 40%) with previously undiagnosed diabetes, and low levels of adequate glucose control among previously diagnosed diabetics. Barriers to accessing diagnosis and treatment included a lack of diagnostic tools and glucose monitoring equipment and high cost of diabetes treatment. The total annual cost of diabetes in the region was estimated at US$67.03 billion, or US$8836 per diabetic patient. Diabetes exerts a significant burden in the region, and this is expected to increase. Many diabetic patients face significant challenges accessing diagnosis and treatment, which contributes to the high mortality and prevalence of complications observed. The significant interactions between diabetes and important infectious diseases highlight the need and opportunity for health planners to develop integrated responses to communicable and non-communicable diseases

Knudsen gas provides nanobubble stability

We provide a model for the remarkable stability of surface nanobubbles to bulk dissolution. The key to the solution is that the gas in a nanobubble is of Knudsen type. This leads to the generation of a bulk liquid flow which effectively forces the diffusive gas to remain local. Our model predicts the presence of a vertical water jet immediately above a nanobubble, with an estimated speed of $\sim3.3\,\mathrm{m/s}$, in good agreement with our experimental atomic force microscopy measurement of $\sim2.7\,\mathrm{m/s}$. In addition, our model also predicts an upper bound for the size of nanobubbles, which is consistent with the available experimental data

Plasmonic Bubbles in n-Alkanes

In this paper we study the formation of microbubbles upon the irradiation of an array of plasmonic Au nanoparticles with a laser in n-alkanes ($C_{n}H_{2n+2}$, with n = 5-10). Two different phases in the evolution of the bubbles can be distinguished. In the first phase, which occurs after a delay time {\tau}d of about 100 {\mu}s, an explosive microbubble, reaching a diameter in the range from 10 {\mu}m to 100 {\mu}m, is formed. The exact size of this explosive microbubble barely depends on the carbon chain length of the alkane, but only on the laser power $P_l$. With increasing laser power, the delay time prior to bubble nucleation as well as the size of the microbubble both decrease. In the second phase, which sets in right after the collapse of the explosive microbubble, a new bubble forms and starts growing due to the vaporization of the surrounding liquid, which is highly gas rich. The final bubble size in this second phase strongly depends on the alkane chain length, namely it increases with decreasing number of carbon atoms. Our results have important implications for using plasmonic heating to control chemical reactions in organic solvents

Surface bubble nucleation phase space

Recent research has revealed several different techniques for nanoscopic gas nucleation on submerged surfaces, with findings seemingly in contradiction with each other. In response to this, we have systematically investigated the occurrence of surface nanobubbles on a hydrophobised silicon substrate for various different liquid temperatures and gas concentrations, which we controlled independently. We found that nanobubbles occupy a distinct region of this phase space, occurring for gas concentrations of approximately 100-110%. Below the nanobubble phase we did not detect any gaseous formations on the substrate, whereas micropancakes (micron wide, nanometer high gaseous domains) were found at higher temperatures and gas concentrations. We moreover find that supersaturation of dissolved gases is not a requirement for nucleation of bubbles.Comment: 4 pages, 4 figure

Universal mechanism for air entrainment during liquid impact

When a mm-sized liquid drop approaches a deep liquid pool, both the interface of the drop and the pool deform before the drop touches the pool. The build up of air pressure prior to coalescence is responsible for this deformation. Due to this deformation, air can be entrained at the bottom of the drop during the impact. We quantify the amount of entrained air numerically, using the Boundary Integral Method (BIM) for potential flow for the drop and the pool, coupled to viscous lubrication theory for the air film that has to be squeezed out during impact. We compare our results to various experimental data and find excellent agreement for the amount of air that is entrapped during impact onto a pool. Next, the impact of a rigid sphere onto a pool is numerically investigated and the air that is entrapped in this case also matches with available experimental data. In both cases of drop and sphere impact onto a pool the numerical air bubble volume V_b is found to be in agreement with the theoretical scaling V_b/V_{drop/sphere} ~ St^{-4/3}, where St is the Stokes number. This is the same scaling that has been found for drop impact onto a solid surface in previous research. This implies a universal mechanism for air entrainment for these different impact scenarios, which has been suggested in recent experimental work, but is now further elucidated with numerical results

Concurrent TNFRSF1A R92Q and pyrin E230K mutations in a child with multiple sclerosis

We report a 16-year-old female patient with a severe course of multiple sclerosis and concomitant symptoms suggestive of a hereditary autoinflammatory disease. Genetic analyses revealed that she inherited a TNFRSF1A R92Q mutation from her mother and a pyrin E230K mutation from her father. To our knowledge, this is the first report of a patient with severe childhood multiple sclerosis and mutations in two genes which predispose to hereditary autoinflammatory disorders. We speculate that these mutations contribute to early multiple sclerosis manifestation and enhance the inflammatory damage inflicted by the autoimmune response