ABSTRACT In times of fossil fuel shortage, increasing crude oil prices, as well as rejection of conventional energy sources (e.g. coal or nuclear power plants), sustainable energy forms become more and more the focus of attention. One of several offered solutions is to develop a photovoltaic device (solar cells), since solar energy is abundant. Especially, Namibia receives solar radiation of 5.8 to 6.4 KWh per square meter per day – one of the highest in the world. With 8 to 11 average hou...
Abstract Gold extraction from different type of ores is largely driven by elemental compositions and gold particle size and distribution. Another major factor that contribute to inaccurate gold analysis/ estimation is the nugget effect (presence of gold particulates in different sizes and shapes). Therefore the purpose of the study was to quantify and evaluate the effect of different elements on gold extraction/analysis, establish gold particle size distribution and determine the most suitab...
Abstract To study the optical and photocatalytic properties of zinc oxide (ZnO or zincite), thin films doped with metallic silver-nanoparticles (Ag-NPs), with various amounts of Ag (20 mol% ≤ n ≤ 80 mol%), were fabricated on a quartz glass substrate at 600°C in air using the molecular precursor method (MPM). The fabricated thin films were analysed and X-ray diffraction (XRD) patterns of Ag nanoparticles, zinc oxide, and composite AgNP/ZnO films were measured using an X-ray diffractomete...
ABSTRACT Access to clean and safe water for everyday use is needed for a healthy society. Water treatment and recovery of precious metals is a serious challenge particularly for developing countries since the current technologies are not attractive because they are often expensive and not environmentally friendly. Precious metals such as gold, palladium, and platinum are valuable and hence crucial for any economy. Coagulants used in the treatment and recovery of precious metals have setbacks...
ABSTRACT Plants have long been used to treat ailments such as headaches, stomach-ache, diarrhoea, tumours, wounds and sexually transmitted diseases, just to mention a few. Ziziphus mucronata, Heliotropium ciliatum and Gnidia polycephala are traditionally used to treat tumours and wound-related illnesses. Tumours and persistent wounds can be a sign of cancer. Microbial wound infections can also bring fatal consequences if unattended. This study evaluates the antioxidant, anticancer and antimi...
Abstract The occurrence and distribution of mercury (Hg) and other co-occurring heavy metals in the mining towns of Berg Aukas and Tsumeb in northern Namibia were studied Different forms of Hg and other heavy metals were characterized in soils, water and plants collected in these areas. Total metal concentration was determined using ICP–OES and total Hg was determined using the DMA 80 mercury analyser. Fractionation of Hg and other heavy metals were determined by performing a four step seq...
ABSTRACT The objective of this research was to discover new drug leads from Namibian marine algae. Plocamium extracts were screened and their phytochemical contents were quantified. Both the antioxidant activity and the antimicrobial activity of the crude extracts were determined, as well as the dose-response relationship for Plocamium extracts in BALB/c mice. This was done by using acute and sub-acute toxicity parameters. In addition, the structural elucidation of the major metabolite found...
ABSTRACT In recent years, there has been an increase in fatal road accidents in Namibia claiming many lives each year. Traffic accidents are often related to the use of alcohol, illegal drugs or psychoactive medicines. A rapid low volume dispersive liquid-liquid microextraction (DLLME) method in combination with gas chromatography-mass spectrometry (GC-MS) detection was developed for the simultaneous determination of illicit psychoactive drugs in blood (those used most commonly in Namibia: c...
Abstract Metal nanoparticles are endowed with optical, electrical physical and chemical properties and have become attractive materials for commercialization applications in optical spectroscopies, electrical devices and catalytic applications. Among them, silver nanoparticles (Ag-NPs) have distinctive physico-chemical and biological properties such as antimicrobial, chemical stability and catalytic properties. Namibia, a semi-arid country, relies on man-made dams to obtain water for potable...
ABSTRACT Tephrosia lupinifolia is used traditionally for the treatment of malaria, diarrhea, toothache and tuberculosis. Two flavonoids, lupinifolin and lupinifolinol were previously isolated from the hexane root extract of T. lupinifolia, but there are no reports on phytochemical and pharmacological studies conducted on the stems and leaves of the plant. The purpose of this study was to prepare and fractionate crude extracts from the leaves and stems of T. lupinifolia, and to evaluate their...
ABSTRACT Marine-derived endophytic fungi isolated from mangrove plants are an important and novel resource of natural bioactive compounds with their potential applications in medicine, agriculture and food industry. There are many instances that seem to suggest that, some of the novel metabolites previously isolated from certain species of marine plants and invertebrates are actually metabolites of marine-derived endophytic fungi. In this project, chemical screening of mangrove plantsConocarp...
ABSTRACT There is an ever-growing interest in the Paenibacillus genus as a result of reports that strains belonging to this genus have several important properties. These properties include promotion of plant growth, bioremediation and the biosynthesis of structurally intriguing molecules with unrivalled biological activities and mechanisms of action. However, the agricultural applications of the aforementioned molecules far outweigh their use in medicine. In this current report, a novel Paen...
ABSTRACT Non-ribosomal peptides (NRPs) are currently receiving considerable interests for possible development as effective alternatives to clinically failing conventional small molecule antibiotics. Particularly, NRPs produced by the genus Streptomyces have attracted considerable attention given the antibiotic production history of the genus. In this current report, a novel Ghanaian Streptomyces sp. strain DE2E isolated from the high biodiversity rich wetlands of the Brong-Ahafo Region of Gh...
Abstract Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), is one of the leading causes of death globally, especially in low and middle-income countries. TB is primarily a curable disease, with chemotherapy predicated on a combination of four drugs. The increase in multiple forms of drugresistant TB is a major cause for concern, underpinning the importance of a continuous pipeline of new anti-TB agents. Drug repositioning – that is, the optimization of existing drugs for new th...
ABSTRACT There is an urgent need for new antimalarials following the emergence of Plasmodium falciparum strains with reduced sensitivity to the currently used artemisinin combination therapies. Classical aminoquinoline-based drugs inhibit the formation of haemozoin (HZ) thereby causing parasite death from the cellular accumulation of toxic ‘free’ haem. Coincidentally, this immutable pathway also exists in Schistosoma mansoni, and presents a vulnerable target for drug design in these haema...