Stability of a strongly anisotropic thin epitaxial film in a wetting interaction with elastic substrate

The linear dispersion relation for longwave surface perturbations, as derived by Levine et al. Phys. Rev. B 75, 205312 (2007) is extended to include a smooth surface energy anisotropy function with a variable anisotropy strength (from weak to strong, such that sharp corners and slightly curved facets occur on the corresponding Wulff shape). Through detailed parametric studies it is shown that a combination of a wetting interaction and strong anisotropy, and even a wetting interaction alone results in complicated linear stability characteristics of strained and unstrained films. PACS: 68.55.J, Morphology of films; 81.15.Aa, Theory and models of film growth; 81.16.Dn, Self-assembly.Comment: Accepted in EPL (http://epljournal.edpsciences.org

Electrocatalytic reduction of oxygen at vapor phase polymerized poly(3,4-ethylene- dioxidethiophene) modified glassy carbon electrode

We successfully polymerized poly(3,4-ethylenedioxidethiophene) by vapor phase polymerization technique on rotating glassy carbon disk electrode. The catalytic activity of this electrode towards oxygen reduction reaction was investigated and showed remarkable activity. Rotating disk voltammetry was used to study the kinetics of oxygen reduction reaction by plotting Levich, Koutecky Levich and Tafel plots. It was found that the reduction was mixed diffusion and kinetic controlled. The O2 reduction underwent through four electron transfer reaction. The Tafel slope was obtained as 55 mV/dec. The limiting current density was higher by a factor of more than 103 times the exchange current density.KEYWORDS: Poly(3,4-ethylenedioxidethiophene), Vapor phase polymerization, Oxygen reduction, Glassy carbon electrode Bull. Chem. Soc. Ethiop. 2012, 26(3), 449-454.DOI: http://dx.doi.org/10.4314/bcse.v26i3.1

Dirty hands on troubled waters: Sanitation, access to water and child health in Ethiopia

In this paper, we investigate the impact of access to drinking water sources and sanitation facilities on the incidence of diarrheal diseases among children below 5 years of age in Ethiopia using the propensity score matching technique with a polychotomous treatment variable. We find that among the water sources traditionally considered as improved, only water piped into dwelling, yard or plot leads to a large percentage point reduction in diarrhea incidence. The other water sources, generally believed as clean, are not effective in reducing diarrhea even compared with some of the unimproved water sources. We also find that some unimproved water sources and sanitation facilities are less inferior than they are believed to be. These results suggest that the traditional way of categorizing different types of improved and unimproved water sources and sanitation facilities into a dichotomous variable, “improved” or “unimproved”, could be misleading as it masks the heterogeneous effects of the water sources and the sanitation facilities

Slurry nebulization ICP-OES for the determination of Cu, Fe, Mg, Mn and Zn

A method that involves analysis of bovine liver by slurry nebulization and ICP-OES has been developed. This method permits rapid and accurate determination of Cu, Fe, Mg, Mn and Zn in bovine liver. Aliquots of freeze-dried and powdered bovine liver sample were dispersed in 2.0 M HNO3 and sonicated to homogenize the resulting slurries. Bovine liver samples were also microwave digested or subjected to aqueous extraction for comparison of analytical results. Concentrations of Cu, Fe, Mg, Mn and Zn in aqueous slurries, the digests, and aqueous extracts were determined by the ICP-OES using external calibration curves. A student’s t-test showed that the results obtained using the slurry method were in good agreement at 95 % confidence level (CL) with those of microwave digestion or aqueous extraction techniques, except for Fe. To check the accuracy and precision of the slurry method, a bovine liver CRM was analyzed and good agreement was achieved with the certified values at 95 % CL. The results demonstrate inefficiency of aqueous extraction technique for complete removal of Fe in bovine liver sample. KEY WORDS: Bovine liver, ICP-OES, Slurry nebulization, Cu, Fe, Mg, Mn, Zn   Bull. Chem. Soc. Ethiop. 2008, 22(3), 313-321.

Traditional medicinal plant knowledge and use by local healers in Sekoru District, Jimma Zone, Southwestern Ethiopia

Abstract The knowledge and use of medicinal plant species by traditional healers was investigated in Sekoru District, Jimma Zone, Southwestern Ethiopia from December 2005 to November 2006. Traditional healers of the study area were selected randomly and interviewed with the help of translators to gather information on the knowledge and use of medicinal plants used as a remedy for human ailments in the study area. In the current study, it was reported that 27 plant species belonging to 27 genera and 18 families were commonly used to treat various human ailments. Most of these species (85.71%) were wild and harvested mainly for their leaves (64.52%). The most cited ethnomedicinal plant species was Alysicarpus quartinianus A. Rich., whose roots and leaves were reported by traditional healers to be crushed in fresh and applied as a lotion on the lesions of patients of Abiato (Shererit). No significant correlation was observed between the age of traditional healers and the number of species reported and the indigenous knowledge transfer was found to be similar. More than one medicinal plant species were used more frequently than the use of a single species for remedy preparations. Plant parts used for remedy preparations showed significant difference with medicinal plant species abundance in the study area.</p

Delay in initiating tuberculosis treatment and factors associated among pulmonary tuberculosis patients in East Wollega, Western Ethiopia

Background: Delay in treatment is also likely to be associated with a greater number of secondary cases per index case. Objective: to assess the length of patient and health system delays; and identify factors influencing these delays among pulmonary tuberculosis patients. Methods: We conducted a cross-sectional study in 13 selected government health facilities that provide both diagnostic and treatment services using Directly Observed Treatment Short course (DOTS) program. Data were collected from pulmonary TB patients aged 15 years and above during their intensive phase of DOTS treatment using a semi-structured questionnaire. Results: The median total delay was 90 days; with 28 days patient delay and 42 days health system delay. A large proportion (63%) of the overall total delay was contributed by health system delay. Patients from urban areas were 46% more likely to present to health care providers than patients from rural areas, adjusted hazard ratio (AHR) of 1.46 (95% CI: 1.10 - 1.95). Patients from urban areas were 54% more likely to be diagnosed and start treatment earlier than patients from rural areas, AHR of 1.54 (95% CI: 1.15-2.07). Female patients were more delayed to present to health providers than their male counterparts with AHR of 0.63 (95%CI: 0.47–0.84) but had shorter health system delay than male patients with AHR of 1.51 (95% CI: 1.1-22.04). Conclusion: A greater proportion of the overall total delay was contributed by health system delay. The health system should be more accessible for the unmet need. New approaches to make health services more accessible to those in greatest need (rural and women) should be designed and developed.The Ethiopian Journal of Health Development Vol. 21 (2) 2007: pp. 148-15

Laparoscopy in management of appendicitis in high-, middle-, and low-income countries: a multicenter, prospective, cohort study.

BACKGROUND: Appendicitis is the most common abdominal surgical emergency worldwide. Differences between high- and low-income settings in the availability of laparoscopic appendectomy, alternative management choices, and outcomes are poorly described. The aim was to identify variation in surgical management and outcomes of appendicitis within low-, middle-, and high-Human Development Index (HDI) countries worldwide. METHODS: This is a multicenter, international prospective cohort study. Consecutive sampling of patients undergoing emergency appendectomy over 6 months was conducted. Follow-up lasted 30 days. RESULTS: 4546 patients from 52 countries underwent appendectomy (2499 high-, 1540 middle-, and 507 low-HDI groups). Surgical site infection (SSI) rates were higher in low-HDI (OR 2.57, 95% CI 1.33-4.99, p = 0.005) but not middle-HDI countries (OR 1.38, 95% CI 0.76-2.52, p = 0.291), compared with high-HDI countries after adjustment. A laparoscopic approach was common in high-HDI countries (1693/2499, 67.7%), but infrequent in low-HDI (41/507, 8.1%) and middle-HDI (132/1540, 8.6%) groups. After accounting for case-mix, laparoscopy was still associated with fewer overall complications (OR 0.55, 95% CI 0.42-0.71, p < 0.001) and SSIs (OR 0.22, 95% CI 0.14-0.33, p < 0.001). In propensity-score matched groups within low-/middle-HDI countries, laparoscopy was still associated with fewer overall complications (OR 0.23 95% CI 0.11-0.44) and SSI (OR 0.21 95% CI 0.09-0.45). CONCLUSION: A laparoscopic approach is associated with better outcomes and availability appears to differ by country HDI. Despite the profound clinical, operational, and financial barriers to its widespread introduction, laparoscopy could significantly improve outcomes for patients in low-resource environments. TRIAL REGISTRATION: NCT02179112

The State of Addis Ababa 2021: Towards a Healthier City

The 'State of Addis Vol. II: Toward a healthier city' was written by an international multidisciplinary team, as the pandemic was unfolding. The report assesses the relationship between urban form and function and the spread of the COVID-19 pandemic, in Addis Ababa. It explores what is meant by a healthy city, and why planning for and investing in a healthy city, matters to Addis Ababa. It goes on to investigate the state of health, urban infrastructure and social services in the city. The socio-economic and health impacts of the pandemic are also explored further, together with the institutional response to the public health emergency. The findings provide insights on the role of urban form and infrastructure to urban health and urban resilience. Finally, the authors highlight a post-pandemic agenda for a healthier, more resilient city