Exponential Tracking Control Using Backstepping Approach for Voltage-Based Control of a Flexible Joint Electrically Driven Robot

This paper addresses the design of exponential tracking control using backstepping approach for voltage-based control of a flexible joint electrically driven robot (EFJR), to cope with the difficulty introduced by the cascade structure in EFJR dynamic model, to deal with flexibility in joints, and to ensure fast tracking performance. Backstepping approach is used to ensure global asymptotic stability and its common algorithm is modified such that the link position and velocity errors converge to zero exponentially fast. In contrast with the other backstepping controller for electrically driven flexible joint robot manipulators control problem, the proposed controller is robust with respect to stiffness uncertainty and allows tracking fast motions. Simulation results are presented for both single link flexible joint electrically driven manipulator and 2-DOF flexible joint electrically driven robot manipulator. These simulations show very satisfactory tracking performances and the superiority of the proposed controller to those performed in the literature using simple backstepping methodology

Crossed Fused Renal Ectopia: A Rare Malformation Diagnosed in Context of Pyelonephritis in Yaounde – Cameroon

The authors report a case of crossed renal ectopia with fusion of the upper renal poles, a rare congenital anomaly of the urinary system in which one of the two kidneys is on the contralateral side, the ureter of the ectopic kidney crosses the midline to plug into the bladder on the normal side. For this 8-year-old male patient, radiological exploration was performed for periumbilical and hypogastric abdominal pain with fever and dysuria caused by a pyelonephritis. Some cases of crossed-renal ectopia remain asymptomatic and the diagnosis is often incidental. Abdominal ultrasound is the first-line imaging technique for the diagnosis which is confirmed by the CT-scan. The interest of this case is both epidemiological, diagnostic and didactic because it is very rare and the medical imaging plays an important role to underpin this diagnosis

Crossed Fused Renal Ectopia: A Rare Malformation Diagnosed in Context of Pyelonephritis in Yaounde – Cameroon

The authors report a case of crossed renal ectopia with fusion of the upper renal poles, a rare congenital anomaly of the urinary system in which one of the two kidneys is on the contralateral side, the ureter of the ectopic kidney crosses the midline to plug into the bladder on the normal side. For this 8-year-old male patient, radiological exploration was performed for periumbilical and hypogastric abdominal pain with fever and dysuria caused by a pyelonephritis. Some cases of crossed-renal ectopia remain asymptomatic and the diagnosis is often incidental. Abdominal ultrasound is the first-line imaging technique for the diagnosis which is confirmed by the CT-scan. The interest of this case is both epidemiological, diagnostic and didactic because it is very rare and the medical imaging plays an important role to underpin this diagnosis

Dementia and cognitive impairment in French-speaking Sub-Saharan Africa: a comprehensive review on moving out of the shadows of neglect

Dementia is a global public health problem with increasing prevalence and incidence worldwide. The African continent is expected to bear the biggest brunt of the burden of dementia by 2050 because of the rapid demographic changes, including rapid population growth, an increase in life expectancy, and ageing. However, French-speaking Sub-Saharan African (FS-SSA) countries are underrepresented in research on dementia in Africa. While the reasons are diverse and complex, linguistic and cultural barriers to research, disproportionately affect these countries and may be significant factors. Any efforts, therefore, to redress the burden of dementia in Africa must consider the specific demographic, cultural, and linguistic characteristics of FS-SSA countries. This scoping review explores the current state of knowledge in dementia and cognitive impairment in Sub-Saharan Africa, highlighting research gaps and specific patterns unique to FS-SSA Africa. We identify pathways for research to bridge the knowledge gaps on dementia in FS-SSA as part of the global endeavor to tackle dementia worldwide

Adaptive Algorithms for Performance Improvement of a Class of Continuum Manipulators

International audienc

HIV-Infected or -Exposed Children Exhibit Lower Immunogenicity to Hepatitis B Vaccine in Yaoundé, Cameroon: An Appeal for Revised Policies in Tropical Settings?

<div><p>Background</p><p>Since 2005, anti-hepatitis B virus (anti-HBV) vaccine is part of the Expanded Program on Immunization (EPI) for infants born in Cameroon, with 99% anti-HBV coverage. In a context of generalized HIV epidemiology, we assessed paediatric anti-HBV vaccine response according to HIV status, feeding option and age in a tropical context.</p><p>Methodology</p><p>Prospective, observational and cross-sectional study conducted among 82 children (27 [IQR: 9–47] months, min-max: 6–59), after complete anti-HBV vaccination (Zilbrix Hepta: 10μg AgHBs) at the Essos Health Centre in Yaounde, Cameroon, classified as group-A: HIV unexposed (28), group-B: HIV-exposed/uninfected (29), group-C: HIV-infected (25). Quantitative anti-HBs ELISA was interpreted as “no”, “low-” or “protective-response” with <1, 1–10, or ≥10 IU/L respectively; with p-value<0.05 considered significant.</p><p>Results</p><p>Children were all HBV-unexposed (AcHBc-negative) and uninfected (HBsAg-negative). Response to anti-HBV vaccine was 80.49% (66/82), with only 45.12% (37/82) developed a protective-response (≥10IU/L). According to HIV status, 60.71% (17/28) developed a protective-response in group-A, vs. 51.72% (15/29) and 20% (5/25) in group-B and group-C respectively, Odds Ratio (OR): 2.627 [CI_95% 0.933–7.500], p = 0.041. According to feeding option during first six months of life, 47.67% (21/45) developed a protective-response on exclusive breastfeeding vs. 43.24% (16/37) on mixed or formula feeding, OR: 1.148 [CI_95% 0.437–3.026], p = 0.757. According to age, protective-response decreased significantly as children grow older: 58.33% (28/48) <24 months vs. 26.47% (9/34) ≥24 months, OR: 3.889 [CI_95% 1.362–11.356], p = 0.004; and specifically 67.65% (23/34) ≤6 months vs. 0%, (0/5) 33–41 months, p = 0.008.</p><p>Conclusions</p><p>Anti-HBV vaccine provides low rate of protection (<50%) among children in general, and particularly if HIV-exposed, infected and/or older children. Implementing policies for early vaccination, specific immunization algorithm for HIV-exposed/infected children, and monitoring vaccine response would ensure effective protection in tropical settings, pending extensive/confirmatory investigations.</p></div

Anti-HBV vaccine response in HIV-infected vs. HIV-uninfected children.

<p>In red are the highest rates of response after anti-HBV vaccination in each category of children.</p