The design of an instrument to measure physical science teachers' topic specific pedagogical content knowledge in electrochemistry.

Research has ranked electrochemistry as one of the more difficult topics to teach and learn. Examiners in South Africa have complained about the poor performance in electrochemistry related concepts in Grade 12 public exams. This may suggest that the physical science teachers may not be teaching it very well. Accomplished teachers use specialized knowledge to transform their knowledge of subject matter into a form that can easily be understood by learners, known as pedagogical content knowledge (PCK). Little is known about the quality of PCK of teachers within this topic and currently there is no instrument to measure quality of topic specific PCK of practicing physical science teachers. The main purpose of the study was to design and validate an instrument that could be used to measure the quality of topic specific PCK of practicing physical science teachers in electrochemistry. The study was a methodology study which used a Mixed Methods (MM) approach. MM were used because the design of the instrument requires both qualitative and quantitative methods in the various steps towards its creation. The topic specific PCK (TSPCK) theoretical framework guided the design of the instrument. TSPCK comprises of 5 components namely: (i) Learners’ Prior Knowledge including misconceptions; (ii) Curricular Saliency; (iii) What makes topic easy or difficult to understand; (iv) Representations or models; and (v) Conceptual teaching Strategies that enables transformation of content knowledge into its teachability. The new instrument was designed to elucidate TSPCK in electrochemistry according to these five components which each component represented a test item. The design process followed these steps chronologically: (i) Conceptualization of test items, (ii) construction of the instrument and judgment of items, (iii) piloting and construction of the actual instrument and finally validation of the instrument. After its conceptualization and development, the instrument was validated with a convenience sample of 21 practicing physical science teachers in Johannesburg schools, Gauteng province, South Africa. A topic specific PCK rubric was used to score the teachers’ responses on a 4 point scale-from 1 “limited” to 4 “Exemplary” Topic Specific PCK. The Rasch Winsteps program analysed the teachers’ scores and ascertained the validity of the instrument through statistics of goodness of fit. In addition, the Rasch 2 model determined the hierarchy difficulty of topic specific PCK components as well as instrument reliability. Both the items and persons’ responses fell within an acceptable conventional range of -2 and +2 Infit/outfit statistics. The item and person reliability indices of the developed instrument were 0.97 and 0.89 respectively. The results show that it is possible to design an instrument that is valid and reliable instrument. Data on content knowledge of teachers was collected using the Content Knowledge test. It was found that a high concentration of teachers possessed a sound knowledge of electrochemistry but with a corresponding low topic specific PCK. This is likely the reason of poor performance of grade 12 learners in exams on electrochemistry related topics. Furthermore, a positive statistically significant linear relationship was found to exist between Content knowledge and the measured teachers’ topic specific PCK. The findings suggest that TSPCK instrument might be used for teaching purposes so as to boost the practicing teachers’ TSPCK on electrochemistry. In addition, the findings suggest that the instrument might be incorporated as a training tool in inservice teacher workshops

Phytochemical profiling and isolation of bioactive compounds from Leucosidea sericea (Rosaceae)

In the study, ultra-performance liquid chromatography–quadrupole time-of-flight–mass spectrometry analysis of Leucosidea sericea leaf and stem extracts led to the identification of various classes of compounds. Further chromatographic purifications resulted in the isolation of 22 compounds that consisted of a new triterpenoid named leucosidic acid A (1), an acetophenone derivative 2, a phloroglucinol derivative 3, three chromones 4–6, seven pentacyclic triterpenoids 7–13, a phytosterol glucoside 14, a flavonoid 15, and seven flavonoid glycosides 16–22. Nineteen of these compounds including the previously undescribed triterpenoid 1 are isolated for the first time from L. sericea. The structures of the isolated compounds were assigned based on their high-resolution mass spectrometry and nuclear magnetic resonance data. Some of the isolated triterpenoids were evaluated for inhibitory activity against α-amylase, α-glucosidase, and pancreatic lipase. Of the tested compounds, 1-hydroxy-2-oxopomolic acid (7) and pomolic acid (13) showed higher potency on α-glucosidase than acarbose, which is used as a positive control in this study. The two compounds inhibited α-glucosidase with IC50 values of 192.1 ± 13.81 and 85.5 ± 6.87 μM, respectively.National Research Foundation of South Africa, University of Pretoria and South African Nuclear Energy Corporation Ltd.http://pubs.acs.org/journal/acsodfBiochemistryChemistryGeneticsMicrobiology and Plant Patholog

Triterpenoids from Protorhus longifolia exhibit hypocholesterolemic potential via regulation of cholesterol biosynthesis and stimulation of low-density lipoprotein uptake in HepG2 cells

The increasing incidence of hypercholesterolemia-related diseases even in the presence of the currently available cholesterol-lowering drugs indicates a need to discover new therapeutic drugs. This study aimed to investigate the hypocholesterolemic potential of two triterpenoids isolated from Protorhus longifolia stem bark. In silico techniques and in vitro enzyme assays were used to evaluate the potential inhibition of cholesterol esterase and HMGCoA reductase by the triterpenoids (ARM-2 and RA-5). The toxicity, modulation of low-density lipoprotein (LDL) uptake, and associated gene expression were determined in HepG2 hepatocytes. In silico molecular docking revealed that ARM-2 compared with RA-5 has a relatively stronger binding affinity for both enzymes. Both triterpenoids further demonstrated promising in silico drug-likeness properties and favorable ADMET profiles characterized by high intestinal absorption and lack of CYP450 enzyme inhibition. The compounds further showed, to varying degrees of efficacy, inhibition of cholesterol micellization as well as both cholesterol esterase and HMG-CoA reductase activities with IC50 values ranging from 16.4 to 41.1 μM. Moreover, enhanced hepatic cellular LDL uptake and the associated upregulation of the LDL-R and SREBP-2 gene expression were observed in the triterpenoid-treated HepG2 cells. It is evident that the triterpenoids, especially ARM-2, possess hypocholesterolemic properties, and these molecules can serve as leads or structural templates for the development of new hypocholesterolemic drugs.http://pubs.acs.org/journal/acsodfam2024AnatomyBiochemistryGeneticsMicrobiology and Plant PathologyNon

Reading tabloids in Zulu: a case study of Isolezwe

This article revolves around an analysis of the relationship between Isolezwe newspaper, a South African mass-market tabloid, and its consumers who are mainly Zulu-speaking black readers. In view of the decline in  newspaper readership in general, the phenomenal growth of Isolezwe in particular and the absence of scholarship that examines the relationship between Isolezwe and its consumers, the authors set out to explore why the newspaper has become and continues to be highly popular. To answer the question about the reason for its popularity, focus group interviews with readers were conducted to identify why readers chose to read the newspaper. The authors conclude that the comparative preference of Isolezwe over other newspapers in the market is influenced, in part, by mutually reinforcing factors such as social/cultural identity and cultural capital, semantic noise avoidance, language use, gratification of cognitive needs and the audiencecentred definition of news

BRICS journalists in global research

This chapter provides an introduction to international comparative research about journalists with a focus on the BRICS countries. It reports the early results of a study of BRICS journalists, from 2012 to 2016, which aims to scrutinize and understand the media systems of BRICS through the human dimension, taking a view from within, from the subjective world of the journalist-practitioners themselves. Each of the BRICS countries has its particular history of development of media and journalism, and of research about journalists. Attempts to classify media systems based on different criteria have long been part of the literature. The BRICS countries are among the top ten growing economies with the greatest share of investments in global advertising markets: China holds the second place, Brazil the third, Russia the fifth and India the ninth. Journalism is a popular profession in the BRICS countries, especially among the young, particularly in China and South Africa. This chapter provides an introduction to international comparative research about journalists with a focus on the BRICS countries. It reports the early results of a study of BRICS journalists, from 2012 to 2016, which aims to scrutinize and understand the media systems of BRICS through the human dimension, taking a view from within, from the subjective world of the journalist-practitioners themselves. Each of the BRICS countries has its particular history of development of media and journalism, and of research about journalists. Attempts to classify media systems based on different criteria have long been part of the literature. The BRICS countries are among the top ten growing economies with the greatest share of investments in global advertising markets: China holds the second place, Brazil the third, Russia the fifth and India the ninth. Journalism is a popular profession in the BRICS countries, especially among the young, particularly in China and South Africa

<b>Smart monitoring of sewage infrastructure to alleviate environmental pollution</b>

The problem of environmental pollution resulting from sewage spillage is a significant concern in South Africa, a country with aging infrastructure. Municipalities, particularly local municipalities located in rural and semi-rural areas, are tasked with the collection and treatment of household sewage. Manual monitoring methods currently in use are labour-intensive, prone to inaccuracies, and lack real-time data capabilities. This study investigates the feasibility of deploying intelligent monitoring technology to address sewage-related pollution issues. The proposed intelligence involves the utilization of sensors capable of real-time data collection and feedback, aimed at preventing sewage spillage and addressing it promptly. The research is conducted within a local municipality in semi-rural South Africa, serving as a worst-case scenario with findings applicable to more developed regions within the country. The envisioned system leverages advanced technologies and adheres to IEEE standards such as IEEE 1451 for sensor interoperability and IEEE 802.11 for wireless communication. Its primary objectives are real-time monitoring, early pollution detection, and rapid intervention to prevent sewage spillage. A comprehensive literature review highlights the shortcomings of manual sewage monitoring and explores the potential of smart sensors and data-driven solutions in mitigating sewage pollution. The research involves the development of monitoring models and data analytics using MATLAB, with a specific focus on the pump station and sump section of the sewer network. The implementation of this smart sensor and data-driven sewage monitoring system enhances resource allocation efficiency, enables targeted maintenance, and ensures timely responses. The integration of electrical and automation technologies further enhances the reliability, accuracy, and scalability of sewage monitoring operations. The study's findings contribute to the formulation of effective pollution management strategies, inform policy-making decisions, and provide guidance for the implementation of smart monitoring systems in municipalities. These outcomes contribute to sustainable development efforts and a cleaner, healthier environment in South Africa, offering a transferable solution applicable to regions worldwide facing similar challenges.</p

Molecular basis of the anti-hyperglycemic activity of RA-3 in hyperlipidemic and streptozotocin-induced type 2 diabetes in rats

Abstract Background Insulin resistance is a hallmark of type 2 diabetes mellitus (T2DM) and the underlying cause of various metabolic changes observed in type 2 diabetic patients. This study investigated the molecular basis of the anti-hyperglycemic activity of the lanosteryl triterpene (RA-3), from Protorhus longifolia stem bark, in hyperlipidemic and streptozotocin (STZ)-induced T2DM in rats. Methods The high-fat diet fed (HFD) and STZ-induced T2DM in rat model was used to evaluate the anti-hyperglycemic activity of RA-3. The hyperlipidemic rats received a single intraperitoneal injection of STZ (35 mg/kg body weight) to induce T2DM. The experimental animals received a daily oral single dose of RA-3 (100 mg/kg body) for a period of 28 days, whiles the control group received distilled water only. The animals were euthanized, and skeletal muscle was collected for protein (IRS-1, AKT, GSK and GLUT 4) expression analysis. Western blot confirmed expression of the proteins. Results Treatment of the diabetic animals with the RA-3 showed marked reduction in fasting plasma glucose levels in comparison to the untreated diabetic group animals. A significant decrease in p-GSK-3β and p-AKT expression was observed, whereas the expression of IRS-1ser307 were increased when compared to the diabetic control group. This effect was ablated upon treatment with RA-3 and this was concomitant to an observed increase in GLUT 4 expression. Conclusions The results obtained in the present study strongly suggested that the anti-hyperglycemic effect of RA-3 could partly be associated with its ability to improve cellular glucose uptake in muscle tissue from T2DM

δ¹⁵N and δ¹³C descriptive statistics for two species in shared and non-shared ponds.

<p>These statistics were evaluated from original isotopic values (without specific diet discrimination correction).</p><p>δ¹⁵N and δ¹³C descriptive statistics for two species in shared and non-shared ponds.</p

Coverage of the Russia-Ukraine war by television news

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