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Item Sorghum, its proteins and Thai LIME Shouldn’t the Use of Kaffir, Kafir, Kaffirin and Kafirin as Common Nouns be Discontinued?(International Journal of CRITICAL DIVERSITY STUDIES 5.2, 2022) Komeine, NantangaIt is trite that most Indigenous food resources in former politically colonised nations have been given English or some other Western common or trivial names. The oppressed people especially in southern Africa were not spared from derogatory and/or racist names such as Kaffir or Kafir, a derogatory reference name equivalent to Nigga or Negro that was used in America. Over time and as political freedom and independence were gained through liberation struggles between the colonisers and the colonised, the use of derogatory and/or racist names against the formerly oppressed people became legally actionable. It is almost forgotten that the offensive, derogatory and/or racist names were not limited to the oppressed people. The natural environments, land and other resources such as Indigenous plants, fruits, rivers, serene spaces and animals were also apparently named by the colonisers and Western botanists or those who allegedly discovered these resources, even though the Indigenous names for such resources existed before the arrival of different agents of colonialisation.Item The photon‐electrical conversion efficiency of dye‐sensitivesolar cells fabricated using a highly conductive silver‐nanoparticle/titania photocathode(Wiley‐VCH GmbH, 2023) Daniel, Likius S.; Kaffer, Rocha T.; Kalipi, Loini M.; Rahman, Ateeq; Kalengay, Mbela; Uahengo, VeikkoThe TiO2 thin film, Ag NP and three Ag‐NP/TiO2 composite thin films (COMP‐Agn; n = 20, 50, and 75 Ag mol%) were successfully fabricated on quartz glass. The optical properties of the composite electrodes were investigated, and the results indicate a surface plasmonic resonance peak at 410 nm while the electrical resistivity of the composite thin films improved up to 6.9 × 10−5 Ω cm. The photo‐response threshold of the Ag‐NP/TiO2 composite thin films was enhanced and shifted into the visible and near‐infrared when the chlorophyll dye was adsorbed onto them. The hall effect was performed on the fabricated thin films and the charge carrier concentrate value confirmed that the Ag/TiO2 with Ag concentrate >45% are found to be p‐type. The n‐types were observed till the Ag content in TiO2 was increased up to 45 mol%. COMP‐Ag75 has a charge carrier concentration of 1.3 × 10−19 cm−3 as a p‐type electrode was then employed to construct a p‐DSSC. Such enhancement on photovoltaic activity can be attributed to the generated Z‐scheme system in the anatase/rutile phase‐junction Ag/TiO2 photocathode enhances the separation, diffusion, and transformation of electron/hole pairs inside the structure. This p‐DSSC exhibits a photon‐electrical conversion efficiency (PCE) of 0.37%. The PCE recorded is equal to or greater than those of traditional high‐efficiency n‐DSSCs. This allows the creation of a new generation of photocathodic p‐DSSCs with previously unheard‐of unprecedentedly high concentrations of Ag (up to 80 mol%) evenly scattered in a TiO2 matrix, and this efficacy is the highest ever reported for a p‐type working Ag/TiO2/chlorophyll/iodine electrode. This may enable the use of this electrode as a component of photosensitizer tandem devices.Item Mass spectrometric analysis of cucurbitacins and dihydrocucurbitacins from the tuber of citrullus naudinianus(MDPI, 2023) Moritz, Benka; Görlitz, Kristof; Schöttgen, Michael C.; Lagies, Simon; Mohl, Daniel A.; Kather, Michel; Du Preez-Bruwer, Lwanette; Mumbengegwi, Davis; Teufel, Robin; Kowarschik, Stefanie; Huber, Roman; Plattner, Dietmar A.; Kammerer, BerndThe vast pool of structurally and functionally distinct secondary metabolites (i.e., natural products (NPs)) is constantly being expanded, a process also driven by the rapid progress in the development of analytical techniques. Such NPs often show potent biological activities and are therefore prime candidates for drug development and medical applications. The ethyl acetate extract of the tuber of Citrullus naudinianus (C. naudinianus), an African melon with edible fruits and seeds, shows in vitro immunomodulatory activity presumably elicited by cucurbitacins that are known major constituents of this plant. Further potentially immunomodulatory cucurbitacins or cucurbitacin derivatives were assumed to be in the tuber. Given the typically high content of cucurbitacins with similar physicochemical features but often distinct bioactivities, an efficient and reliable separation process is a prerequisite for their detailed characterization and assessment in terms of bioactivity. We therefore developed a detection method to screen and differentiate cucurbitacins via high-performance liquid chromatography/quadrupole-time-of-flight tandem mass spectrometry (HPLC-QTOF-MS/MS). In order to confirm the identification, the fragmentation patterns of two cucurbitacins and one 23,24-dihydrocucurbitacin were also investigated. Six characteristic fragments were identified and three of them were employed for the identification of cucurbitacins and 23,24- dihydrocucurbitacins in the extract. As a result, in addition to eight previously reported cucurbitacins from this plant four distinct 23,24-dihydrocucurbitacins (B, D, E, and I) were putatively identified and newly found in the ethyl acetate extract of the tuber of C. naudinianus. The established methodology enables rapid and efficient LC-MS-based analysis and identification of cucurbitacins and 23,24- dihydrocucurbitacins in plant extracts.Item Baseline characterization of entomological drivers of malaria transmission in Namibia(MBC, 2023) Lukubwe, Ophilia; Mwema, Tabeth; Joseph, Rosalia; Maliti, Deodatus; Litula, Litula; Katokele, Stark; Uusiku, Petrina; Walusimbi, Dennis; Ogoma, Sheila B.; Gueye, Cara S.; Vajda, Elodie; Tatarsky, Allison; Thomsen, Edward; Tambo, Munya; Mumbengegwi, Davis; Lobo, Neil F.Background Namibia’s focus on the elimination of malaria requires an evidence-based strategy directed at understanding and targeting the entomological drivers of malaria transmission. In 2018 and 2019, the Namibia National Vector-borne Diseases Control Program (NVDCP) implemented baseline entomological surveillance based on a question-based approach outlined in the Entomological Surveillance Planning Tool (ESPT). In the present study, we report on the findings of the ESPT-based NVDCP on baseline vector species composition and bionomic traits in malaria endemic regions in northern Namibia, which has the aim of generating an evidence base for programmatic decision-making.Methods Nine representative sentinel sites were included in the 2018 entomological surveillance program (Kunene, Omusati, Oshana, Ohangwena, Oshikoto, Otjozondjupa, Kavango West, Kavango East and Zambezi); the number was reduced to four sites in 2019 due to limited funding (Ohangwena, Kavango West, Kavango East, and Zambezi). In the 2018 baseline collections, multiple sampling methods (human landing catches, pyrethroid spray catches, U.S. Centers for Disease Control and Prevention light traps [CDC-LTs], resting boxes [RBs] and larval sampling) were utilized to evaluate indoor/outdoor human biting rates, resting behaviors and insecticide resistance (IR). CDC-LTs and RBs were not used in 2019 due to low and non-representative sampling efcacies. Results Overall, molecular evidence demonstrated the presence of three primary mosquito vectors, namely Anopheles arabiensis, rediscovered Anopheles gambiae sensu stricto and Anopheles funestus sensu stricto, alongside Anopheles squamosus and members of the Anopheles coustani complex. Vectors were found to bite throughout the night (1800 hours 0600 hours) both indoors and outdoors, with An. arabiensis having the highest biting rates outdoors. Low numbers of indoor resting Anopheles point to possible low indoor residual spraying (IRS) efcacy—with An. arabiensis found to be the major vector species resting indoors. The IR tests demonstrated varying country-wide resistance levels to the insecticide deltamethrin, with the resistance levels confrmed to have increased in 2019, evidence that impacts national programmatic decision-making. Vectors demonstrated susceptibility to the insecticides dichlorodiphenyltrichloroethane, bendiocarb and Actellic 300CS in 2018, with mosquitoes from only one site (Kavango West) demonstrating possible resistance to DDT. Targeted and question-based entomological surveillance enabled a rapid and focused evidence base to be built, showing where and when humans were being bitten and providing entomological data on long-lasting insecticidal nets, IRS efcacy and insecticide resistance, which the Ministry of Health and Social Services-Namibia can use to further build a monitoring and evaluation framework for understanding the drivers of transmission. Conclusion Identifcation and characterization of species-specifc bionomic traits allows for an understanding of where and when vector human contact may occur as well as the potential impact of interventions. Low indoor resting rates as well as the presence of insecticide resistance (and the increase in its frequency) point to the need for mosquito-behavior-directed and appropriate interventions as well as the requirement for a resistance mitigation strategy. The ESPT-based question- and minimal essential indicator-based operational research strategy provides programs with directed and focused data for facilitating decision-making while requiring limited funding and capacity. Keywords Entomological drivers, Malaria, NamibiaItem The production of activated carbon from Acacia erioloba seedpods via phosphoric acid activation method for the removal of methylene blue from water.(Elsevier, 2023) Rahman, Ateeq; Hamushembe, Mirjam N.; Kapolo, Paulus; Daniel, Likius S.; Uahengo, Veikko; Jonnalagadda, Sreekantha B.Wastewater treatment requires a lot of granular activated carbon to absorb the dissolved organic components. This article describes a low-cost process for making highly active adsorption activated carbons from biomass, which could be used for wastewater treatment. A one-step carbonization and chemical activation with phosphoric acid at 500 ◦C produced low-cost acacia-derived porous activated carbons. The activated carbons’ moisture, ash, volatile matter, and fixed carbon content were determined using proximate analysis. The activated carbon’s adsorption qualities were also determined by studying its bulk density, surface morphology, power of hydrogen, iodine number, and methylene blue number index. To test the produced activated carbons for water treatment, batch adsorption dynamics were performed at room temperature for the removal of methylene blue from aqueous solution. Compared to activation using H2SO4, H3PO4 proves superior in generating welldeveloped pores, leading to a mesoporosity and microporosity structure with a larger surface area and high adsorption capacity. Brunauer–Emmett–Teller determined the sample’s specific surface area, which was found to be 387 m2 /g. The iodine number for 50, 100, and 200 μm activated carbon particles size was 620, 592, and 632 mg/g, respectively. The adsorption of MB on AC material better fits with Langmuir’s adsorption isotherm; hence, particles are adsorbed on well-pronounced heterogeneous surfaces. The sips model is found to best represent the equilibrium data with R2 values of 0.994, suggesting the heterogeneous surface adsorption of MB on AC. Therefore, the adsorption of AC by MB involves physical and chemical processes. The produced AC hence appears to remove dissolved organic contaminants from raw water.Item Phase 3 evaluation of an innovative simple molecular test for the diagnosis of malaria in different endemic and health settings in sub Saharan Africa (DIAGMAL)(PLOS ONE, 2022) Kiemde, FrancoisRapid Diagnostic Tests (RDTs) have become the cornerstone for the management of malaria in many endemic settings, but their use is constrained for several reasons: (i) persistent malaria antigen (histidine-rich protein 2; HRP2) leading to false positive test results; (ii) hrp2 deletions leading to false negative PfHRP2 results; and (iii) limited sensitivity with a detection threshold of around 100 parasites/μl blood (pLDH- and HRP2-based) leading to false negative tests. Microscopy is still the gold standard for malaria diagnosis, and allows for species determination and quantitation, but requires trained microscopists, maintained microscopes and has detection limit issues. Consequently, there is a pressing need to develop and evaluate more sensitive and accurate diagnostic tests. To address this need we have developed a direct on blood mini PCR-NALFIA test that combines the benefits of molecular biology with low infrastructural requirements and extensive training. Methods This is a Phase 3 diagnostic evaluation in 5 African countries. Study sites (Sudan, Ethiopia, Burkina, Kenya and Namibia) were selected to ensure wide geographical coverage of Africa and to address various malaria epidemiological contexts ranging from high transmission to near elimination settings with different clinical scenarios and diagnostic challenges. Study participants will be enrolled at the study health facilities after obtaining written informed consent. Diagnostic accuracy will be assessed following the WHO/TDR guidelines for the evaluation of diagnostics and reported according to STARD principles. Due to the lack of a 100% specific and sensitive standard diagnostic test for malaria, the sensitivity and specificity of the new test will be compared to the available diagnostic practices in place at the selected sites and to quantitative PCR as the reference test.Item The in-vivo dynamics of Plasmodium falciparum HRP2: Implications for the use of rapid diagnostic tests in malaria elimination(BMC, 2022) Marquart, LouiseAbstract Background: Rapid diagnostic tests (RDTs) that rely on the detection of Plasmodium falciparum histidine-rich protein 2 (PfHRP2) have become key tools for diagnosing P. falciparum infection. The utility of RDTs can be limited by PfHRP2 persistence, however it can be a potential benefit in low transmission settings where detection of persistent PfHRP2 using newer ultra-sensitive PfHRP2 based RDTs can serve as a surveillance tool to identify recent exposure. Better understanding of the dynamics of PfHRP2 over the course of a malaria infection can inform optimal use of RDTs. Methods: A previously published mathematical model was refined to mimic the production and decay of PfHRP2 during a malaria infection. Data from 15 individuals from volunteer infection studies were used to update the original model and estimate key model parameters. The refined model was applied to a cohort of patients from Namibia who received treatment for clinical malaria infection for whom longitudinal PfHRP2 concentrations were measured. et al. Malaria Journal (2022) 21:233 https://doi.org/10.1186/s12936-022-04245-z Malaria Journal Results: The refinement of the PfHRP2 dynamic model indicated that in malaria naïve hosts, P. falciparum parasites of the 3D7 strain produce 33.6 × 10−15 g (95% CI 25.0–42.1 × 10−15 g) of PfHRP2 in vivo per parasite replication cycle, with an elimination half-life of 1.67 days (95% CI 1.11–3.40 days). The refined model included these updated parameters and incorporated individualized body fluid volume calculations, which improved predictive accuracy when compared to the original model. The performance of the model in predicting clearance of PfHRP2 post treatment in clinical samples from six adults with P. falciparum infection in Namibia improved when using a longer elimination halflife of 4.5 days, with 14% to 67% of observations for each individual within the predicted range. Conclusions: The updated mathematical model can predict the growth and clearance of PfHRP2 during the production and decay of a mono-infection with P. falciparum, increasing the understanding of PfHRP2 antigen dynamics. This model can guide the optimal use of PfHRP2-based RDTs for reliable diagnosis of P. falciparum infection and re-infection in endemic settings, but also for malaria surveillance and elimination programmes in low transmission areas. Keywords: Rapid diagnostic tests, Plasmodium falciparum, Histidine rich protein, Antigen dynamics, Elimination and surveillanceItem The Namibian bioeconomy: Transformation to a sustainable society?(Springer, 2020) Hauser, Anne Heeren; Cheikhyoussef, Ahmad; Chimwamurombe, Percy M.Worldwide, bioeconomy is promoted as an ‘engine for sustainable development’. However, increasingly, the notion that ‘the bioeconomy’ will facilitate sustainable development per se is challenged. Based on the assumption that when leaving the relations between ‘nature’ and ‘society’ unquestioned, inherent inequalities are rather reproduced than overcome, we draw upon a social-ecological framework to analyse the societal relations to nature in the Namibian bioeconomy. In Namibia, with independence, an array of diferent beneft-sharing mechanisms have been developed to implement local participatory governance structure, which will be further streamlined under the newly introduced access and beneft-sharing law. Results show that despite eforts to facilitate a diversity-based bioeconomy, separating structures and trade-ofs are persistent. Images of ‘nature’, like the ‘eternal Namibian landscape’, that draw upon colonial notions are frequently used to market indigenous natural products. Institutions to ‘nature’ that guarantee fair and equitable terms of trade are often only short-term and/or small-scale, e.g. as shown at the case of Devil’s claw, Hoodia and Namibian Myrrh. Even when perspectives cannot be assigned in a stereotypical way between user and provider, and instead, all actors refer to biodiversity and traditional knowledge as ‘welfare of the people’, ‘cultural heritage’, ‘input for R&D’, ‘community beneft’, and ‘marketing tool’, a rational-instrumental reasoning tends to be favoured of a normative-ethical one. A more diversifed awareness towards the dialectics entailed in the conception, making, and management of ‘nature’ potentially inhibiting an inclusive sustainable development is relevant at any theory–practice interface, including development project-management and environmental policy-making.Item Chapter 4 - Clove (Syzygium aromaticum) polysaccharides(Elsevier, 2022) Cheikhyoussef, AhmadClove (Syzygium aromaticum (L.) Merr. & Perry) is an essential herb with well-documented health benefits. Carbohydrates were detected in the ethanolic bud extract of S. aromaticum. Two antithrombotic polysaccharides were isolated from the flower buds of clove by anion-exchange chromatography, hydrophobic interaction column chromatography, and size exclusion chromatography with molecular weight ranging from ca. 34,000 to ca. 103,000 Da. Clove polysaccharides have the backbone of type I rhamnogalacturonan, and the side chain of arabinan with the sulfate is being positioned at 6 of 3-linked galactosyl residues. Although polysaccharides from cloves have an antithrombotic ability, their activities in vitro are lower than that of heparin. Sulfated polysaccharides from cloves show a slightly lower salt concentration due to their relatively low sulfate/sugar ratio, which gives distinctive structural characteristics compared to other polysaccharides such as algae polysaccharides. The anticoagulation action with no toxicity in vivo of low molecular weight sulfated polysaccharide may represent a valuable and safe antithrombotic agent. This chapter gives an overview of polysaccharides from S. aromaticum, their characteristics, and their potential applications.Item Clove (Syzygium aromaticum) phenolics: Extraction, compositions, and biological activities(Elsevier, 2022) Cheikhyoussef, AhmadClove (Syzygium aromaticum L.) is a dried flower bud belonging to the Myrtaceae family indigenous to Indonesia. Recently, it has been farmed in different places worldwide with potential food and nutraceutical applications. Clove volatile compounds contribute to the smell and unique aroma; meanwhile, nonvolatile compounds in the clove are mainly responsible for the taste. Clove is well known for its high level of antioxidants because of the flavonoids, hydroxy benzenes, phenylpropanoids, and other reducing substances. Clove phenolics comprise between 8% and 12% (w/w) gallic acid equivalents and are mainly composed of hydrolyzable tannins, phenolic acids, flavonoids, and eugenol, major bioactive molecules in this valuable herb. Gallic acid is the highest among the phenolic acids in clove and other gallic acid derivatives such as hydrolyzable tannins, which are also present in higher concentrations. Other phenolic acids found in the clove are ellagic, ferulic, caffeic, and salicylic acids. In addition, flavonoids such as quercetin and kaempferol were reported. This chapter will focus on clove phenolics’ structure, composition, and biological activities.Item Kalahari Truffle: An underprized delicacy(Agricuture Economy and Rular development, 2022) Hainghumbi, Tukuna AMushrooms can be edible and are used as food and nutraceuticals. they are mostly collected from the wild and sold as is. Buyers wash and cook them before consumption. This piece assessed the prices of Kalahari truffles mostly at the largest open market where, when they are in season in Namibia, a high concentration of truffles sales occurs. It intelligently argues for the creation of veld food supply chains to improve rular development. The prices of truffles increased toward the end of the growing season. In Namibia & Botswana, the ICT are sold in the informal markets at €4.75 per kg in Namibia, which is significantly lower than €1496.5 per kg in developed nations. the Kalahari Truffles value should be unleashed to enhance the incomes of rural communities via the developments of veld food supply chainsItem Towards the use of undervalued African truffle and pearl millet to modulate glucose release in crackers(2022) Uukule, ErickIndigenous and underutilized food resources can play a role in nutrition. Pearl millet, an underutilized cereal, has slowly digestible starch. However, it hardly features in many diets possibly due to its limited diversified use in high-value convenience food products. some mushrooms also improve postprandial glycaemic responses. this study investigates the effect of compositing Kalahari truffle (KT) with fermented pearl millet and bread wheat flour on the nutrient and in vitro starch digestibility of the crackers. Fermented whole grain pearl millet flour was mixed with bread wheat flour (1:1). KT powder was added to comprise 5, 10 and 15% of the composite flours. KT incorporation significantly increased the cracker's protein and significantly reduce their in vitro starch digestibility.Item True Potatoes Seeds (TPS) as an alternative method for potato production in Namibia(Namibia Journal for Research Science and Technology, 2022) Horn, Lydia NPotato plays a great role in the human diet all over the world for the achievement of food security programs due to its popularity and ability to adapt to different environmental conditions as well as its yielding capacity. Production of potatoes in Namibia however is far less than in other countries due to constraints such as the unavailability of growing materials in the form of true potato seeds (TPS) or seed tubers. This situation is not only denying the opportunity for local farmers to produce potato crops but also limiting the opportunity for Agrobusiness and crop diversification in the country. Without a formal potato seed system, farmers will continue making use of varieties of unknown origin as no improved varieties are available to the majority of the farmers. Lack of awareness about the use of improved technology and practices has also impeded the adoption of potato technologies in Namibia. This review is aimed at summarizing challenges and constraints to potato Production and value chain in Namibia, and to provide baseline information on the potato for current and aspiring producers in Namibia or similar agro-ecologies in Sub-Saharan Africa (SSA)Item A ruthenium bipyridyl molecular dye sensitizer and an excited‑state intermolecular proton transfer‑active colorimetric probe for anions, with high affinity towards CN− in DMSO(2022) Naimhwaka, Johannes HA ruthenium bipyridyl-dye sensitizer (N) based on the naphthyl-thiazole anchoring-ancillary ligand was synthesized and characterized using spectroscopic methods of UV–Vis, 1H NMR, FTIR and fluorescence. The functional properties of N were investigated through its photoinduced and intramolecular based charge transfer mechanisms. Subsequently, N displayed interesting charge transfer-based properties (ESIPT) that are complementary to molecular photovoltaic and chemosensing properties. The properties were investigated and studied in dimethyl sulfoxide (DMSO), due to its polar nature and solubility of the dye. Dye sensitizer exhibitions were investigated through solvatochromism effect on the optoelectronic properties, while chemosensing abilities were inspected through colorimetric activities, upon molar addition of anions. Thus, it was established that a dual functional N is a potential dye sensitizer with optoelectronic properties displaying high molar extinction coefficients in acetone. In addition, it was found that N is a colorimetric and fluorometric probe selective and sensitive to biologically important anions of CN−, F−, OH− and AcO− through fluorescence enhancement, as a result of hydrogenbonding leading to deprotonation. The sensing probe, however, displayed more strongly association with CN−.Item Cost and cost effectiveness of reactive case detection (RACD), reactive focal mass drug administration (rfMDA) and reactive focal vector control (RAVC) to reduce malaria in the low endemic setting of Namibia: an analysis alongside a 2×2 factorial design cluster randomised controlled trial(MBJ, 2022) Ntuku, HenryObjectives To estimate the cost and cost effectiveness of reactive case detection (RACD), reactive focal mass drug administration (rfMDA) and reactive focal vector control (RAVC) to reduce malaria in a low endemic setting. Setting The study was part of a 2×2 factorial design cluster randomised controlled trial within the catchment area of 11 primary health facilities in Zambezi, Namibia. Participants Cost and outcome data were collected from the trial, which included 8948 community members that received interventions due to their residence within 500 m of malaria index cases. Ntuku H, et al. BMJ Open 2022;12:e049050. doi:10.1136/bmjopen-2021-049050 Outcome measures The primary outcome was incremental cost effectiveness ratio (ICER) per in incident case averted. ICER per prevalent case and per disability- adjusted life years (DALY) averted were secondary outcomes, as were per unit interventions costs and personnel time. Outcomes were compared as: (1) rfMDA versus RACD, (2) RAVC versus no RAVC and (3) rfMDA+RAVC versus RACD only. Results rfMDA cost 1.1x more than RACD, and RAVC cost 1.7x more than no RAVC. Relative to RACD only, the cost of rfMDA+RAVC was double ($3082 vs $1553 per event). The ICERs for rfMDA versus RACD only were $114, $1472 and $842, per incident case averted, respectively. Using prevalent infections and DALYs as outcomes, trends were similar. the median personnel time to implement rfMDA was 20% lower than for RACD (30 vs 38 min per person). The median personnel time for RAVC was 34 min per structure sprayed. Conclusion Implented alone or in combination, rfMDA and RAVC were cost effective in reducing malaria incidence and prevalence despite higher implementation costs in the intervention compared with control arms. compared with RACD, rfMDA was time saving. Cost and time requirements for the combined intervention culd be decreased by implementing rfMDA and RAVC simultaneously by single team. Trial registration number NCT02610400; Post resultsItem Assessment of microbiological properties, mycotoxins, and heavy metals in underprized raw Kalahari truffles sold in Namibia(Journal of Food Quality and Hazards Control, 2022) Hainghumbi, T.A.Kalahari truffle (Kalaharituber pfeilii) is found in the Kalahari desert and nearby regions (Africa). This study assessed the microbiological quality and safety, mycotoxins, and heavy metals contents of raw Kalahari truffle sold in Namibia. Methods: Batches of Kalahari truffles were purchased from informal markets and different vendors in Namibia. Total aerobic, coliform, yeast, and moulds counts, and Salmonella were assessed. Also, some mycotoxins and heavy metals were determined. Data were analyzed using SPSS Statistics Software, Version 25. Results: Total aerobic count of unwashed truffles ranged from 4.4 to 7.3 log Colony Forming Unit (CFU)/g. Total coliform counts detected in truffles were 6.0 log CFU/g. Salmonella was not detected. Doxynivalenol was the most prevalent mycotoxin. Fumonisin B1 levels ranged from 17.4 to 142.1 µg/kg. Ochratoxin A levels in unwashed truffles ranged from 0.1 to 48.5 µg/kg. Total aflatoxin levels were 26.3 to 27.5 µg/kg, while zearalenone levels ranged from 45.0 to 9,680 µg/kg. The iron content was up to 746.72 mg/kg. Cadmium and zinc were detected in the studied samples, but mercury and nickel were no detectable in any samples. Conclusion: The studied truffle samples were safe in terms of Salmonella, mercury, and nickel. However, some of the detected microorganisms, mycotoxins, and heavy metals in underprized Kalahari truffles may impair the safety, shelf life, and human health. Thus, they should be subjected to appropriate processing before consumption. © 2022, Shahid Sadoughi University of Medical Sciences. This is an open access article under the Creative Commons Attribution 4.0 International License.Item In vitro antimalarial properties and chemical composition of Diospyros chamaethamnus extracts(Elsevier, 2022) Du Preez, IwannetteDiospyros chamaethamnus, a low woody perennial, which is endemic to Namibia, Botswana, Angola, and Zambia, is used in the management of malaria. The current study aimed to assess the effectiveness of this plant against malaria parasites and to identify some of the compounds, which may be responsible for the therapeutic properties of this plant. Dried roots were macerated in dichloromethane-methanol (1:1 v/v) and water to isolate phytoconstituents, which were then screened for antimalarial activity using the P. falciparum chloroquine-sensitive strain, D10. Furthermore, the antioxidant activities of the plant extracts were deter-mined using the DPPH method. Lastly, the plant extracts were analyzed by gas chromatography-mass spectrometry. Moderate in vitro antiplasmodial activity (IC50 < 50 mg/ml) was observed for the D. chamae-thamnus organic (19.51 mg/mL) and aqueous (18.30 mg/mL) extracts. Antioxidant activity based on DPPH scavenging potential showed that D. chamaethamnus aqueous and organic extracts exhibited significant anti-oxidant activities with IC50 values of 7.63 and 10.74 mg/mL, respectively. Some of the biologically active com- pounds found in the extracts of D. chamaethamnus include lupeol, palmitic acid, stigmasterol, and pyrogallol. These findings support the use of D. chamaethamnus against malaria and/or malaria-associated symptoms and provide a foundation or guide for further studies of this plant as an alternative treatment option for malaria.Item Photocatalytic degradation of rhodamine B dye and hydrogen evolution by hydrothermally synthesized NaBH4-Spiked ZnS Nanostructures.(Frontiers, 2022) Amakali, TeopolinaMetal sulphides, including zinc sulphide (ZnS), are semiconductor photocatalysts that have been investigated for the photocatalytic degradation of organic pollutants as well as their activity during the hydrogen evolution reaction and water splitting. However, devising ZnS photocatalysts with a high overall quantum efficiency has been a challenge due to the rapid recombination rates of charge carriers. Various strategies, including the control of size and morphology of ZnS nanoparticles, have been proposed to overcome these drawbacks. In this work, ZnS samples with different morphologies were prepared from zinc and sulphur powders via a facile hydrothermal method by varying the amount of sodium borohydride used as a reducing agent. The structural properties of the ZnS nanoparticles were analysed by X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) techniques. All-electron hybrid density functional theory calculations were employed to elucidate the effect of sulphur and zinc vacancies occurring in the bulk as well as (220) surface on the overall electronic properties and absorption of ZnS. Considerable differences in the defect level positions were observed between the bulk and surface of ZnS while the adsorption of NaBH4 was found to be highly favourable but without any significant effect on the band gap of ZnS. The photocatalytic activity of ZnS was evaluated for the degradation of rhodamine B dye under UV irradiation and hydrogen generation from water. The ZnS nanoparticles photo-catalytically degraded Rhodamine B dye effectively, with the sample containing 0.01 mol NaBH4 being the most efficient. The samples also showed activity for hydrogen evolution, but with less H2 produced compared to when untreated samples of ZnS were used. These findings suggest that ZnS nanoparticles are effective photocatalysts for the degradation of rhodamine B dyes as well as the hydrogen evolution, but rapid recombination of charge carriers remains a factor that needs future optimization.Item Characterization of schinziophyton rautanenii (Manketti) nut oil from Namibia rich in conjugated fatty acids and tocopherol(Elsevier, 2018) Cheikhyoussef, NataschaThe Schinziophyton rautanenii tree is an important food source for many communities of the African continent. Oil extracted from the Manketti nut is of great economic value, due to its unique composition and properties. In this study, the physical and chemical characteristics of the oil obtained from three extraction methods – cold pressed, traditional and Soxhlet extraction – were investigated and compared. Oil yield of the nut was found to be 42.6 ± 0.84%. Good quality characteristics, including saponification values (184–189 mg KOH/g), iodine values (120–131 g/100 g), acid values (0.959–2.44 mg KOH/g) and peroxide values (1.80–3.98 meqO2/kg) were found for the Manketti nut oil. The total tocopherol content was in the range of 144–206 mg/100 g of oil, with γtocopherol as the dominant tocopherol. The oil was rich in conjugated fatty acids, α-eleostearic (9Z,11E,13Eoctadecatrienoic acid) (24–36%) and linoleic acid (9Z,12Z-octadeca-9,12-dienoic acid) (31–32%), making it a potential candidate in the nutraceutical and cosmetics industry.Item A ruthenium bipyridyl molecular dye sensitizer and an excited‑state intermolecular proton transfer‑active colorimetric probe for anions, with high afnity towards CN− in DMSO(Springer, 2021) Naimhwaka, Johannes HAbstract A ruthenium bipyridyl-dye sensitizer (N) based on the naphthyl-thiazole anchoring-ancillary ligand was synthesized and characterized using spectroscopic methods of UV–Vis, 1 H NMR, FTIR and fuorescence. The functional properties of N were investigated through its photoinduced and intramolecular based charge transfer mechanisms. Subsequently, N displayed interesting charge transfer-based properties (ESIPT) that are complementary to molecular photovoltaic and chemosensing properties. The properties were investigated and studied in dimethyl sulfoxide (DMSO), due to its polar nature and solubility of the dye. Dye sensitizer exhibitions were investigated through solvatochromism efect on the optoelectronic properties, while chemosensing abilities were inspected through colorimetric activities, upon molar addition of anions. Thus, it was established that a dual functional N is a potential dye sensitizer with optoelectronic properties displaying high molar extinction coefcients in acetone. In addition, it was found that N is a colorimetric and fuorometric probe selective and sensitive to biologically important anions of CN−, F−, OH− and AcO− through fuorescence enhancement, as a result of hydrogenbonding leading to deprotonation. The sensing probe, however, displayed more strongly association with CN−. Keywords Molecular photovoltaic · Ruthenium dye sensitizer · Colorimetric probe · Solvatochromism · CN− sensor