Matabola K.P.,UNISA |
Van Der Merwe E.M.,University of Pretoria |
Strydom C.A.,North West University South Africa |
Labuschagne F.J.W.,University of Pretoria
Journal of Chemical Technology and Biotechnology | Year: 2010
BACKGROUND: The influence of different hydrating agents on the pH of the hydrating solutions, rate of hydration of MgO to Mg(OH)2 and product surface area was studied as a function of temperature of hydration. Hydrating agents used were aqueous solutions of ammonium chloride, magnesium acetate, magnesium nitrate, nitric acid, acetic acid, magnesium chloride, sodium acetate and hydrochloric acid and distilled water as control. These were chosen to determine either the effect of addition of a common ion, the effect of changing the solution pH or due to the presence of an acetate ion, found earlier to have a beneficial effect on the hydration of MgO. RESULTS: There was no significant difference in the hydration behaviour of the hydrating agents up to 50 °C, where less than 10% of magnesium hydroxide was formed. The amount of hydroxide increased at temperatures above 60 °C. When compared with the hydration in water, all the hydrating agents, with the exception of sodium acetate, showed a significant increase in the degree of hydration. Sodium acetate formed the lowest amount of magnesium hydroxide, ranging between 1.2 and 12.2% magnesium hydroxide. The largest percentage (56.7%) of magnesium hydroxide was formed from hydration in magnesium acetate. CONCLUSION: It seems that MgO hydration is a dissolution-precipitation process controlled by the dissolution of MgO. The increased degree of hydration in magnesium acetate is possibly due to the presence of acetate and Mg2+ ions. © 2010 Society of Chemical Industry.
Sivaramakrishna A.,Vellore Institute of Technology |
Clayton H.S.,UNISA |
Muralikrishna U.,Andhra University
Journal of Coordination Chemistry | Year: 2011
This review provides an overview of the synthetic pathways, structures, and reactivity of various nickel(IV) complexes. The complexes are classified according to the various ligand types including sulfur, oxygen, nitrogen, and phosphorus donors. The main emphasis is on different ligand systems which stabilize Ni in higher oxidation state in the solid state and solution. The structural aspects of the complexes are briefly discussed. The possible applications of these nickel(IV) complexes are reviewed and future prospects are also highlighted. © 2011 Taylor & Francis.
Ramudzuli M.R.,University of Pretoria |
South African Journal of Science | Year: 2014
Arsenic-based compounds have been used for cattle dipping for about half a century to combat East Coast Fever in cattle in South Africa. The government introduced a compulsory dipping programme in communal areas to eradicate the disease in 1911. Concern has been raised regarding the ecological legacy of the use of arsenic-basedcompounds in these areas. We investigated the incidence of arsenic residue in soil at 10 dip sites in the Vhembe district of Limpopo Province, South Africa. We found high levels of arsenic contamination at a depth of 300 mm at some sites. Control samples indicated that these high arsenic levels are the result of the application of inorganic arsenic. Variation of arsenic concentrations is attributed to duration of exposure to the chemical, soil properties and distance from the dip tank. Concerns are raised regarding the structural condition of the dip tanks, encroaching villages and possible health threats to the human population in the area. © 2014. The Authors. Published under a Creative Commons Attribution Licence.
Curationis | Year: 2010
The aftermath of the HIV and AIDS pandemic has resulted in great suffering in terms of loss of income, poor quality of life, morbidity and mortality, with children being destitute and orphaned at an alarming rapid rate. Families and communities are currently unable to cope with the effects of HIV and AIDS with special emphasis on the care and support of the affected orphans and vulnerable children, who as a result have been compelled to look after themselves giving rise to a new type of family, the child-headed household. The emergence of this type of family requires government's response in terms of care and support. The purpose of this study was to provide a broad picture of the location, prevalence, composition, functions, needs and challenges of child-headed households in South Africa, and explore available and required services, resources and safety nets for children in child-headed households. An exploratory and descriptive design was used for the purpose. The sample consisted of children heading households and those living in the households that are headed by children; government departments responsible for child welfare, such as, the Departments of Social Development, Health, Education and Agriculture; non-profit organisations and communities where these households are predominant. From the data collected, it was found that the rights of the affected children were compromised. Those heading the households were often not at school and were responsible for domestic chores. The households needed food, clothes, money, shelter, and education. Government in attempting to address these needs required clear policies which will provide a distinction between orphaned and vulnerable children and child-headed households. The study recommended a collaborative approach as it was shown that there was no single model of best practice to appropriately and effectively address the needs of child-headed households.
Deribew A.,Jimma University |
Deribe K.,Brighton and Sussex Medical School |
Reda A.A.,Haromaya University |
Tesfaye M.,Jimma University |
And 2 more authors.
BMC Psychiatry | Year: 2013
Background: The relationship between TB/HIV co-infection and common mental disorders (CMD) is not well investigated. A follow up study was conducted to assess the change in CMD over a 6-months period and its predictors among TB/HIV co-infected and HIV patients without TB in Ethiopia.Methods: A longitudinal study was conducted in 2009. A total of 465 HIV/AIDS patients without TB and 124 TB/HIV co-infected patients from four antiretroviral treatment (ART) centers in Ethiopia were recruited to assess CMD and quality of life (QoL). CMD and QoL were assessed at baseline and at six month using the Kessler-10 scale and the short Amharic version of the World Health Organization Quality of Life Instrument for HIV clients (WHOQOL HIV-Bref) respectively. Multivariate analysis was conducted using generalized estimating equations (GEE) using STATA to assess change in CMD and its predictors.Results: At the 6 month, 540 (97 TB/HIV co-infected and 455 HIV/AIDS patients without TB) patients completed the follow up and 8.6% (21% among TB/HIV co-infected and 2.2% among HIV patients without TB) lost to follow-up.At baseline, 54.4% of TB/HIV co-infected patients had mild to severe mental disorder compared to 41.2% among HIV patients without TB. At the six month follow up, 18.1% of TB/HIV co-infected patients had mild to severe mental disorder compared to 21.8% among HIV patients without TB. The decline of the prevalence of any form of metal disorder was 36.3% among TB/HIV co-infected patients compared to 19.4% among HIV patients without TB (P<0.001).QoL was strongly associated with CMD in TB/HIV co-infected patients and HIV patients without TB (β = -0.04, P<0.001) after controlling the effect of several confounding variables such as sex, income, WHO disease stage, duration on ART, CD4 lymphocyte count, adherence to ART and social support.Conclusion: The prevalence of CMD has significantly reduced particularly among TB/HIV co-infected patients over a 6 months period. Poor QoL is the major independent predictors of CMD. We recommend integration of mental health services in TB/HIV programs. Training of health care providers at TB/HIV clinics could help to screen and treat CMD among TB/HIV co-infected patients. © 2013 Deribew et al.; licensee BioMed Central Ltd.