South African Journal of Science最新文献_第7页

Binary and ternary metals adsorption from greywater using spent green tea as a novel adsorbent 用废绿茶作为新型吸附剂吸附灰水中的二元和三元金属

IF 2.4 4区综合性期刊

South African Journal of Science Pub Date : 2023-08-08 DOI: 10.17159/sajs.2023/13352

Raphael Boaka Hlordze Gameli, E. H. Alhassan, Abudu Ballu Duwiejuah, E. D. Abarike, Abdul-Aziz Bawa

{"title":"Binary and ternary metals adsorption from greywater using spent green tea as a novel adsorbent","authors":"Raphael Boaka Hlordze Gameli, E. H. Alhassan, Abudu Ballu Duwiejuah, E. D. Abarike, Abdul-Aziz Bawa","doi":"10.17159/sajs.2023/13352","DOIUrl":"https://doi.org/10.17159/sajs.2023/13352","url":null,"abstract":"Adsorption is one of the most easy-to-operate, less costly, efficient and, most importantly, environmentally friendly methods of removing toxic metals from aqueous environments. We used spent Impra Green Tea Ginseng Flavoured to recover mercury (Hg2+), lead (Pb2+) and cadmium (Cd2+) in binary and ternary systems from greywater. We undertook this study in binary and ternary systems at adsorbent dosages with a corresponding 100 mL varied initial metal concentrations of the greywater. The adsorption efficiency at varied concentrations and dosages in the binary systems by the spent tea waste ranged from 38.5% to 100% for lead, 11.50% to 100% for cadmium and was 100% for mercury. In the ternary system, the adsorption efficiency of toxic metals ranged from 28.91% to 72.85% for cadmium and was 100% for mercury and lead. The maximum adsorption capacity (Qe) for toxic metals in the binary system ranged from 38.46 to 81.97 mg/g for Pb2+ and 12.64 to 56.82 mg/g for Cd2+. The Langmuir adsorption isotherm model was the best fit for the adsorption of toxic metals by Impra Green Tea Ginseng Flavoured. The pH under which the experiments were conducted showed very high removal efficiency for lead and mercury but lower removal efficiencies for cadmium. Spent Impra Green Tea Ginseng Flavoured can be used as an effective and low-cost adsorbent of toxic metals from greywater or wastewater. Based on our findings, further studies should be conducted to determine the effects of varying the contact time, temperature and elevated metal concentrations in the greywater or other wastewater.","PeriodicalId":21928,"journal":{"name":"South African Journal of Science","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43440884","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Toward an open access genomics database of South Africans: Legal considerations 建立南非开放获取基因组数据库的法律考虑

IF 2.4 4区综合性期刊

South African Journal of Science Pub Date : 2023-08-08 DOI: 10.17159/sajs.2023/15069

D. Thaldar, Amy Gooden, D. Donnelly

引用次数: 0

Construction and testing of a low-cost device for the collection of rainfall samples destined for stable isotope analysis 用于收集稳定同位素分析的降雨样本的低成本装置的建造和测试

IF 2.4 4区综合性期刊

South African Journal of Science Pub Date : 2023-08-08 DOI: 10.17159/sajs.2023/14914

J. Holmes, J. Fitchett

{"title":"Construction and testing of a low-cost device for the collection of rainfall samples destined for stable isotope analysis","authors":"J. Holmes, J. Fitchett","doi":"10.17159/sajs.2023/14914","DOIUrl":"https://doi.org/10.17159/sajs.2023/14914","url":null,"abstract":"Oxygen- and hydrogen-isotope ratios in rainfall provide important hydroclimatic information, yet despite a global network of rainfall isotope measurements, significant geographical gaps exist in data coverage, with only three long-term stations spanning the southern African region. Project-based, ad hoc collections of rainfall for isotope analysis can improve this coverage. However, all rainfall samples that are destined for stable isotope analysis must be collected in such a way to avoid evaporation and resultant isotope fractionation. While such rainwater collectors are available commercially, both the product and shipping are prohibitively costly. We describe the construction of a simple rainfall collector using a design from the literature and materials that are readily available in South African hardware stores. Our rainwater collector can be constructed for the much lower cost of just under ZAR820 in comparison with the cost of ZAR9300 inclusive of shipping from commercial outlets (2022 prices). Our design modifications have the added advantage of portability, with the rainwater collector housed in a bucket with a handle. The device was tested by comparing its performance, in terms of evaporative water loss and isotopic fractionation, with that of an open bottle, using tap water in both cases. Testing confirmed that the collector prevented evaporation over a one-week period, indicating that it is suitable for weekly or more frequent sampling of rainfall. Although the design described was based on materials procured in South Africa, it could easily be adapted for construction elsewhere.","PeriodicalId":21928,"journal":{"name":"South African Journal of Science","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46165667","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

In vitro cytotoxic and apoptotic activity of the Mauritian marine sponge Neopetrosia exigua 毛里求斯海绵体Neopetrosia exigua的体外细胞毒性和凋亡活性

IF 2.4 4区综合性期刊

South African Journal of Science Pub Date : 2023-08-08 DOI: 10.17159/sajs.2023/13745

R. Beesoo, R. Bhagooli, T. Bahorun, V. Neergheen

{"title":"In vitro cytotoxic and apoptotic activity of the Mauritian marine sponge Neopetrosia exigua","authors":"R. Beesoo, R. Bhagooli, T. Bahorun, V. Neergheen","doi":"10.17159/sajs.2023/13745","DOIUrl":"https://doi.org/10.17159/sajs.2023/13745","url":null,"abstract":"Marine sponges belonging to the genus Neopetrosia represent a quasi-inexhaustible source of novel cytotoxic compounds. Yet studies delineating their molecular mechanisms of action in cancer cells remain scarce. We investigated the cytotoxic and apoptosis inducing potential of the Mauritian marine sponge Neopetrosia exigua derived crude extract, hexane and ethyl acetate fraction. Their cytotoxic activity was screened against four cancer cell lines and two non-malignant cell lines via the Alamar Blue metabolic assay. The level of intracellular reactive oxygen species (ROS) production, endogenous antioxidant enzyme activity (catalase and superoxide dismutase) and mitochondrial membrane potential were determined. The ability of the active extract to induce apoptosis in cancer cells and modulate the expression levels of apoptotic markers (caspases and polyADP-ribose polymerase (PARP)) was further evaluated via western blot. The ethyl acetate fraction (NEEAF) displayed the highest inhibitory effect with an IC50 of 6.87 μg/mL against the liver hepatocellular carcinoma cell line (HepG2). Mechanistically, NEEAF induced morphological hallmarks characteristic of apoptosis, increased ROS production, decreased catalase and superoxide dismutase activity and mitochondrial membrane depolarisation in a concentration-dependent manner compared to the control (p<0.05). In addition, NEEAF induced the activation of caspase-9, -7, -3 and cleavage of PARP. Overall, this study provides biochemical evidence for oxidative stress-mediated cytotoxicity and apoptosis in HepG2 cells by NEEAF. Further in-depth investigations are needed to isolate the active constituents, which may potentially lead to the development of novel anticancer therapeutics.","PeriodicalId":21928,"journal":{"name":"South African Journal of Science","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43180136","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A timely, deeper, and complex analysis of dysfunctionality in South African public universities 对南非公立大学功能失调的及时、深入和复杂的分析

IF 2.4 4区综合性期刊

South African Journal of Science Pub Date : 2023-08-08 DOI: 10.17159/sajs.2023/16073

N. Madondo

引用次数: 0

Repurposing research data for commercial use: POPIA, a foil or a facilitator? 将研究数据重新用于商业用途:POPIA，陪衬还是推动者?

IF 2.4 4区综合性期刊

South African Journal of Science Pub Date : 2023-08-08 DOI: 10.17159/sajs.2023/15075

B. Townsend, Amy Gooden, M. Botes, D. Thaldar

引用次数: 0

Land cover change in marginalised landscapes of South Africa (1984–2014): Insights into the influence of socio-economic and political factors 南非边缘景观的土地覆盖变化(1984-2014):对社会经济和政治因素影响的见解

IF 2.4 4区综合性期刊

South African Journal of Science Pub Date : 2023-08-08 DOI: 10.17159/sajs.2023/10709

Buster Mogonong, J. Fisher, D. Furniss, Debbie Jewitt

{"title":"Land cover change in marginalised landscapes of South Africa (1984–2014): Insights into the influence of socio-economic and political factors","authors":"Buster Mogonong, J. Fisher, D. Furniss, Debbie Jewitt","doi":"10.17159/sajs.2023/10709","DOIUrl":"https://doi.org/10.17159/sajs.2023/10709","url":null,"abstract":"Rural landscapes in South Africa experience high conversion rates due to intense land use; however, the changes are site specific and depend on the socio-economic and political history of the area. Land cover change (LCC) was assessed in response to socio-economic and political factors in uThukela Municipal District, KwaZulu-Natal, using Landsat imagery from 1984 to 2014, while making comparisons to other studies in South Africa. Socio-economic/political data were used to gain insights into the observed LCC patterns. Land cover was classified using a random forest classifier, and accuracies ranging from 87% to 92% were achieved. Systematic and intensity analysis methods were used to describe patterns, rates, and transitions of LCC in Imbabazane (ILM) and Okhahlamba (OLM) local municipalities. The results showed a reduced rate of change intensity from 3.4% to 0.9% in ILM and from 3.1% to 1.1% in OLM between 1984 and 2014. Grassland was persistent, covering over 70% in both local municipalities between 1984 and 2014. Although persistent, grassland experienced respective losses of 3.7% and 14.3% in both observation periods in ILM and of 10.2% and 13.3% in OLM. During the analysis period, settlements and cropland gained actively in both local municipalities. The changes represent a degree of population, local authority, and people’s perception as influencers of land use and LCC. It is therefore argued that socio-economic and political changes can potentially influence land use and LCC; however, natural ecosystems can persist under those conditions, and this requires more research efforts.","PeriodicalId":21928,"journal":{"name":"South African Journal of Science","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44236255","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Barry Dwolatzky (1952–2023): In memoriam 巴里·德沃拉茨基（1952–2023）：纪念

IF 2.4 4区综合性期刊

South African Journal of Science Pub Date : 2023-08-08 DOI: 10.17159/sajs.2023/16358

D. Limebeer

引用次数: 0

Exploring the dynamics of the relationship between South Africa and southern Mozambique 探讨南非与莫桑比克南部关系的动态

IF 2.4 4区综合性期刊

South African Journal of Science Pub Date : 2023-08-08 DOI: 10.17159/sajs.2023/15840

Bárbara Direito

引用次数: 0

Future climate change in the Agulhas system and its associated impact on South African rainfall 未来阿古拉斯系统的气候变化及其对南非降雨的相关影响

IF 2.4 4区综合性期刊

South African Journal of Science Pub Date : 2023-08-08 DOI: 10.17159/sajs.2023/13733

Houraa Daher, B. Kirtman

{"title":"Future climate change in the Agulhas system and its associated impact on South African rainfall","authors":"Houraa Daher, B. Kirtman","doi":"10.17159/sajs.2023/13733","DOIUrl":"https://doi.org/10.17159/sajs.2023/13733","url":null,"abstract":"South African climate variability has been linked to changes in both the Agulhas system and external forcing (i.e. CO2 and ozone). We analysed future climate change in the Agulhas system volume transport and its associated impacts on South Africa’s precipitation using the Community Climate System Model version 4 as part of the Coupled Model Intercomparison Project, phase 5. Output from one historical and three future greenhouse gas emission scenarios were examined to project various climate storylines. We found that the Agulhas Current volume transport decreases across all three scenarios and that the current displays a strong baroclinic component with an increase in transport at the surface and decrease at intermediate depths. Agulhas leakage was found to increase with historical emissions. Additionally, an east-west dipole pattern for convective precipitation was found over South Africa, with an increase over the eastern region related to an increase in greenhouse gas emissions and a decrease in the western region linked to the location of Hadley cell edge latitude. Moving into the 21st century, future predictions in regional climate variability are shown to be dependent on the intensity of greenhouse gas emissions and are extremely important for South Africa, a region prone to drought and flooding and home to a large population dependent on rain-fed agriculture.","PeriodicalId":21928,"journal":{"name":"South African Journal of Science","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44117571","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0