12 research outputs found
Epidemiology of neurodegenerative diseases in sub-Saharan Africa: a systematic review
BACKGROUND:Sub-Saharan African (SSA) countries are experiencing rapid transitions with increased life expectancy. As a result the burden of age-related conditions such as neurodegenerative diseases might be increasing. We conducted a systematic review of published studies on common neurodegenerative diseases, and HIV-related neurocognitive impairment in SSA, in order to identify research gaps and inform prevention and control solutions. METHODS: We searched MEDLINE via PubMed, 'Banque de Donnees de Sante Publique' and the database of the 'Institut d'Epidemiologie Neurologique et de Neurologie Tropicale' from inception to February 2013 for published original studies from SSA on neurodegenerative diseases and HIV-related neurocognitive impairment. Screening and data extraction were conducted by two investigators. Bibliographies and citations of eligible studies were investigated. RESULTS: In all 144 publications reporting on dementia (n=49 publications, mainly Alzheimer disease), Parkinsonism (PD, n=20), HIV-related neurocognitive impairment (n=47), Huntington disease (HD, n=19), amyotrophic lateral sclerosis (ALS, n=15), cerebellar degeneration (n=4) and Lewy body dementia (n=1). Of these studies, largely based on prevalent cases from retrospective data on urban populations, half originated from Nigeria and South Africa. The prevalence of dementia (Alzheimer disease) varied between <1% and 10.1% (0.7% and 5.6%) in population-based studies and from <1% to 47.8% in hospital-based studies. Incidence of dementia (Alzheimer disease) ranged from 8.7 to 21.8/1000/year (9.5 to 11.1), and major risk factors were advanced age and female sex. HIV-related neurocognitive impairment's prevalence (all from hospital-based studies) ranged from <1% to 80%. Population-based prevalence of PD and ALS varied from 10 to 235/100,000, and from 5 to 15/100,000 respectively while that for Huntington disease was 3.5/100,000. Equivalent figures for hospital based studies were the following: PD (0.41 to 7.2%), ALS (0.2 to 8.0/1000), and HD (0.2/100,000 to 46.0/100,000). CONCLUSIONS: The body of literature on neurodegenerative disorders in SSA is large with regard to dementia and HIV-related neurocognitive disorders but limited for other neurodegenerative disorders. Shortcomings include few population-based studies, heterogeneous diagnostic criteria and uneven representation of countries on the continent. There are important knowledge gaps that need urgent action, in order to prepare the sub-continent for the anticipated local surge in neurodegenerative diseases
Psychometric Properties and Correlates of Precarious Manhood Beliefs in 62 Nations
Precarious manhood beliefs portray manhood, relative to womanhood, as a social status that is hard to earn, easy to lose, and proven via public action. Here, we present cross-cultural data on a brief measure of precarious manhood beliefs (the Precarious Manhood Beliefs scale [PMB]) that covaries meaningfully with other cross-culturally validated gender ideologies and with country-level indices of gender equality and human development. Using data from university samples in 62 countries across 13 world regions (N = 33,417), we demonstrate: (1) the psychometric isomorphism of the PMB (i.e., its comparability in meaning and statistical properties across the individual and country levels); (2) the PMB’s distinctness from, and associations with, ambivalent sexism and ambivalence toward men; and (3) associations of the PMB with nation-level gender equality and human development. Findings are discussed in terms of their statistical and theoretical implications for understanding widely-held beliefs about the precariousness of the male gender role
Bioaccumulation of copper, cadmium and nickel in Duckweed (Lemna trisulca)
Duckweeds are small free-floating plants often farming dense mats on the surface of stillor slow flowing water. Lemna trisulca (Duckweed) was examined for its ability to remove heavy metals. In laboratory conditions, plants were exposed to the copper, cadmium and nickel concentrations of 1.0,3.0,5.0 and 7.0 mg L-1 in certain periods (24,48,72 and 96 hours). The accumulation levels of metals in plants depending on different time and concentrations were investigated by using atomic absorption spectrometer. The results on bioaccumulation rates of Ni, Cd and Cu ions in Duckweed showed that the plant was able to remove the heavy metals. The maximum BCF values obtained were 541 for Cd, 848 for Cu and 1867 for Ni. Among the metals used, Ni was found to be accumulated at higher levels depending on the metal concentrations and time periods. © by PSP
Polymer supported humic acid for separation and preconcentration of thorium(IV)
The resin impregnating humic acid (HA) onto XAD-4 has been prepared to investigate adsorption behaviour of Th(IV). The characterization of the resulting resin has been carried out by infrared spectral data and sorption capacity. Maximum adsorption capacity of Th(IV) on the resin is found to be 1.51 X 10(-4) mol g(-1) at pH 4. The sorbent was found to possess a high selectivity for Th(IV) with an optimum extraction pH around 3-7. Recoveries for Th(IV) determined prior to breakthrough were found to be quantitative (96-99%). The resin exhibits good chemical stability, reuseability, and a faster rate of equilibration for Th(IV) determination. The influence of several ions as interferents is discussed. The method has been successfully applied for the separation of Th(IV) in synthetic mixtures
Preparation and characterization of polyoxometallates of molybdenum, tungsten and their salts
In this work, confirmation of the molecular formula and investigation of the structural stability of the prepared various types of heteropoly acids and their salts by TGA are reported. Specific surface areas of the samples were determined by the BET-single point N-2 adsorption method. Scanning electron microscopy (SEM) was used for the of surface topography of the samples in the sense of crystalline and amorphous states and the acidities of these solid samples were determined based on the color changes of suitable indicator solutions by the way of a butylamine titration method. Impurities, weight ratios and bonding states of the characteristic elements of the samples were determined from XRD, EDX and FTIR studies